WorldWideScience

Sample records for sun mission epoxi

  1. Properties of an Earth-like planet orbiting a Sun-like star: Earth observed by the EPOXI mission.

    Science.gov (United States)

    Livengood, Timothy A; Deming, L Drake; A'hearn, Michael F; Charbonneau, David; Hewagama, Tilak; Lisse, Carey M; McFadden, Lucy A; Meadows, Victoria S; Robinson, Tyler D; Seager, Sara; Wellnitz, Dennis D

    2011-11-01

    NASA's EPOXI mission observed the disc-integrated Earth and Moon to test techniques for reconnoitering extrasolar terrestrial planets, using the Deep Impact flyby spacecraft to observe Earth at the beginning and end of Northern Hemisphere spring, 2008, from a range of ∼1/6 to 1/3 AU. These observations furnish high-precision and high-cadence empirical photometry and spectroscopy of Earth, suitable as "ground truth" for numerically simulating realistic observational scenarios for an Earth-like exoplanet with finite signal-to-noise ratio. Earth was observed at near-equatorial sub-spacecraft latitude on 18-19 March, 28-29 May, and 4-5 June (UT), in the range of 372-4540 nm wavelength with low visible resolving power (λ/Δλ=5-13) and moderate IR resolving power (λ/Δλ=215-730). Spectrophotometry in seven filters yields light curves at ∼372-948 nm filter-averaged wavelength, modulated by Earth's rotation with peak-to-peak amplitude of ≤20%. The spatially resolved Sun glint is a minor contributor to disc-integrated reflectance. Spectroscopy at 1100-4540 nm reveals gaseous water and carbon dioxide, with minor features of molecular oxygen, methane, and nitrous oxide. One-day changes in global cloud cover resulted in differences between the light curve beginning and end of ≤5%. The light curve of a lunar transit of Earth on 29 May is color-dependent due to the Moon's red spectrum partially occulting Earth's relatively blue spectrum. The "vegetation red edge" spectral contrast observed between two long-wavelength visible/near-IR bands is ambiguous, not clearly distinguishing between the verdant Earth diluted by cloud cover versus the desolate mineral regolith of the Moon. Spectrophotometry in at least one other comparison band at short wavelength is required to distinguish between Earth-like and Moon-like surfaces in reconnaissance observations. However, measurements at 850 nm alone, the high-reflectance side of the red edge, could be sufficient to

  2. The Sun Radio Imaging Space Experiment (SunRISE) Mission

    Science.gov (United States)

    Lazio, Joseph; Kasper, Justin; Maksimovic, Milan; Alibay, Farah; Amiri, Nikta; Bastian, Tim; Cohen, Christina; Landi, Enrico; Manchester, Ward; Reinard, Alysha; Schwadron, Nathan; Cecconi, Baptiste; Hallinan, Gregg; Hegedus, Alex; Krupar, Vratislav; Zaslavsky, Arnaud

    2017-04-01

    Radio emission from coronal mass ejections (CMEs) is a direct tracer of particle acceleration in the inner heliosphere and potential magnetic connections from the lower solar corona to the larger heliosphere. Energized electrons excite Langmuir waves, which then convert into intense radio emission at the local plasma frequency, with the most intense acceleration thought to occur within 20 RS. The radio emission from CMEs is quite strong such that only a relatively small number of antennas is required to detect and map it, but many aspects of this particle acceleration and transport remain poorly constrained. Ground-based arrays would be quite capable of tracking the radio emission associated with CMEs, but absorption by the Earth's ionosphere limits the frequency coverage of ground-based arrays (ν ≳ 15 MHz), which in turn limits the range of solar distances over which they can track the radio emission (≲ 3RS). The state-of-the-art for tracking such emission from space is defined by single antennas (Wind/WAVES, Stereo/SWAVES), in which the tracking is accomplished by assuming a frequency-to-density mapping; there has been some success in triangulating the emission between the spacecraft, but considerable uncertainties remain. We describe the Sun Radio Imaging Space Experiment (SunRISE) mission concept: A constellation of small spacecraft in a geostationary graveyard orbit designed to localize and track radio emissions in the inner heliosphere. Each spacecraft would carry a receiving system for observations below 25 MHz, and SunRISE would produce the first images of CMEs more than a few solar radii from the Sun. Part of this research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration.

  3. "Sunshine": mission to reignite the sun

    CERN Multimedia

    Ebert, Roger

    2007-01-01

    "As a permanent winter settles upon the Earth, a specaship is sent on a desperate mission to drop a nuclear device into the sick sn and "reignite" it. To name the ship "Icarus I" seems like asking for trouble in two ways, considering the fate of the original Icaru and the numeral that omniously leaves room for a sequel." (1 page)

  4. Disruption Tolerant Networking Flight Validation Experiment on NASA's EPOXI Mission

    Science.gov (United States)

    Wyatt, Jay; Burleigh, Scott; Jones, Ross; Torgerson, Leigh; Wissler, Steve

    2009-01-01

    In October and November of 2008, the Jet Propulsion Laboratory installed and tested essential elements of Delay/Disruption Tolerant Networking (DTN) technology on the Deep Impact spacecraft. This experiment, called Deep Impact Network Experiment (DINET), was performed in close cooperation with the EPOXI project which has responsibility for the spacecraft. During DINET some 300 images were transmitted from the JPL nodes to the spacecraft. Then they were automatically forwarded from the spacecraft back to the JPL nodes, exercising DTN's bundle origination, transmission, acquisition, dynamic route computation, congestion control, prioritization, custody transfer, and automatic retransmission procedures, both on the spacecraft and on the ground, over a period of 27 days. All transmitted bundles were successfully received, without corruption. The DINET experiment demonstrated DTN readiness for operational use in space missions. This activity was part of a larger NASA space DTN development program to mature DTN to flight readiness for a wide variety of mission types by the end of 2011. This paper describes the DTN protocols, the flight demo implementation, validation metrics which were created for the experiment, and validation results.

  5. Disruption Tolerant Networking Flight Validation Experiment on NASA's EPOXI Mission

    Science.gov (United States)

    Wyatt, Jay; Burleigh, Scott; Jones, Ross; Torgerson, Leigh; Wissler, Steve

    2009-01-01

    In October and November of 2008, the Jet Propulsion Laboratory installed and tested essential elements of Delay/Disruption Tolerant Networking (DTN) technology on the Deep Impact spacecraft. This experiment, called Deep Impact Network Experiment (DINET), was performed in close cooperation with the EPOXI project which has responsibility for the spacecraft. During DINET some 300 images were transmitted from the JPL nodes to the spacecraft. Then they were automatically forwarded from the spacecraft back to the JPL nodes, exercising DTN's bundle origination, transmission, acquisition, dynamic route computation, congestion control, prioritization, custody transfer, and automatic retransmission procedures, both on the spacecraft and on the ground, over a period of 27 days. All transmitted bundles were successfully received, without corruption. The DINET experiment demonstrated DTN readiness for operational use in space missions. This activity was part of a larger NASA space DTN development program to mature DTN to flight readiness for a wide variety of mission types by the end of 2011. This paper describes the DTN protocols, the flight demo implementation, validation metrics which were created for the experiment, and validation results.

  6. Solar probe mission: close encounter with the sun

    Science.gov (United States)

    Sittler, E. C., Jr.; McComas, D. J.; McNutt, R. L., Jr.; Stdt Team

    The Solar Probe Science and Technology Definition Team (STDT) recently completed a detailed study of the Solar Probe Mission based on an earliest launch date of October 2014. Solar Probe, when implemented, will be the first close encounter by a spacecraft with a star (i.e., 3 RS above the Sun's photosphere). The report and its executive summary were published by NASA (NASA/TM-2005-212786) in September 2005 and can be found at the website http://solarprobe.gsfc.nasa.gov/. A description of the science will appear in Reviews of Geophysics article led by D. J. McComas. For this talk, we presented the consensus view of the STDT including a brief description of the scientific goals, a description of the overall mission, including trajectory scenarios, spacecraft description and proposed scientific payload. We will discuss all these topics and the importance of flying the Solar Probe mission both with regard to understanding fundamental issues of solar wind acceleration and coronal heating near the Sun and Solar Probe's unique role in understanding the acceleration of Solar Energetic Particles (SEPs), which is critical to future Human Exploration.

  7. The Telemachus mission: dynamics of the polar sun and heliosphere

    Science.gov (United States)

    Roelof, E.

    Telemachus in Greek mythology was the faithful son of Ulysses. The Telemachus mission is envisioned as the next logical step in the exploration of the polar regions of the Sun and heliosphere so excitingly initiated by the ESA/NASA Ulysses mission. Telemachus is a polar solar-heliospheric mission described in the current NASA Sun-Earth Connections Roadmap (2003-2028) that has successfully undergone two Team X studies by NASA/JPL. The pioneering observations from Ulysses transformed our perception of the structure and dynamics of these polar regions through which flow the solar wind, magnetic fields and energetic particles that eventually populate most of the volume of the heliosphere. Ulysses carried only fields and particles detectors. Telemachus, in addition to modern versions of such essential in situ instruments, will carry imagers that will give solar astronomers a new viewpoint on coronal mass ejections and solar flares, as well as their first purely polar views of the photospheric magnetic field, thereby providing new helioseismology to probe the interior of the Sun. Unlike the RTG-powered Ulysses, the power for Telemachus will come simply from solar panels. Gravity assist encounters with Venus and Earth (twice) will yield ˜5 years of continuous in-ecliptic cruise science between 0.7 AU and 3.3 AU that will powerfully complement other contemporary solar-heliospheric missions. The Jupiter gravity assist, followed by a perihelion burn ˜8 years after launch, will place Telemachus in a permanent ˜0.2 AU by 2.5 AU heliographic polar orbit (inclination >80 deg) whose period will be 1.5 years. Telemachus will then pass over the solar poles at ˜0.4 AU (compared to 1.4 AU for Ulysses) and spend ˜2 weeks above 60 deg on each polar pass (alternating perihelions between east and west limbs as viewed from Earth). In 14 polar passes during a 10.5 year solar cycle, Telemachus would accumulate over half a year of polar science data. During the remainder of the time, it

  8. An Amateur-Professional International Observing Campaign for the EPOXI Mission: New Insights Into Comets

    Science.gov (United States)

    Meech, K. J.

    2012-06-01

    EPOXI spacecraft and the Arecibo radar observations (Harmon et al. 2011). The model indicates that like other comets, water-ice sublimation began to create an observable dust coma/tail near 4-4.4 AU as the comet approached the sun, but that near perihelion, strong CO2 outgassing in the form of jets (as seen by the spacecraft) was responsible for lifting large ice/dust grains from the surface. CO2 is likely a strong contributor to activity on the outbound leg of the orbit. The models show that the fractional active nucleus area is small for water production (typical of other comets) and that at perihelion most of the water production is likely from the ice grain halo. Sublimation from deeper CO2 reservoirs is likely an important driver of activity for this comet, including out to and beyond aphelion, and this may be a characteristic of unusually active comets - relating to differences in chemistry from either formation or subsequent evolution. This paper will present mission highlights, and emphasize the important role that the amateur observations has in understanding the behavior of this comet.

  9. Earth-Affecting Solar Causes Observatory (EASCO): a mission at the Sun-Earth L5

    DEFF Research Database (Denmark)

    Gopalswamy, Nat; Davila, Joseph M.; Auchère, Frédéric

    2011-01-01

    . The Earth-Affecting Solar Causes Observatory (EASCO) is a proposed mission to be located at the Sun-Earth L5 that overcomes these deficiencies. The mission concept was recently studied at the Mission Design Laboratory (MDL), NASA Goddard Space Flight Center, to see how the mission can be implemented...

  10. High-Performance Data Analysis Tools for Sun-Earth Connection Missions Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The Interactive Data Language (IDL) is a standard tool used by many researchers in observational fields. Present day Sun-Earth Connection missions like SOHO, or...

  11. High-Performance Data Analysis Tools for Sun-Earth Connection Missions Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The Interactive Data Language (IDL) is a standard tool used by many researchers in observational fields. Present day Sun-Earch Connection missions like RHESSI or...

  12. The Sun's Corona Observed by the Skylab Mission

    Science.gov (United States)

    1970-01-01

    The Sun's corona stretches far beyond the dense, irner corona seen in x-rays and ultraviolet light, and beyond the limits of what we normally see in the dark sky of a total solar eclipse. Its farthest reaches are delineated by tapered streamers that stretch into interplanetary space, extending the domain of our nearest star much farther than its visible disk. We see the outer corona briefly at total eclipses of the Sun, where it appears white and delicate against the starry background of a temporarily darkened, daytime sky. Even then, Earth's intervening atmosphere is bright enough to limit our view of the outer corona. At Skylab's orbital altitude, where almost no air was left and where the sky was starkly black, the outer corona was at last clearly seen. In the thousands of coronal portraits made by Skylab, in which the corona was observed more extensively than in all the centuries of humanity's interest in the Sun, the corona was constantly altering its form, ever adjusting to the shifting magnetic fields from the Sun's surface that so obviously gave it its distinctive shape. Skylab's coronagraph observations coupled with x-ray pictures of the inner corona helped establish the origin of the corona's varied forms and the important connection between coronal holes and high-speed streams in the solar wind.

  13. Early Mission Maneuver Operations for the Deep Space Climate Observatory Sun-Earth L1 Libration Point Mission

    Science.gov (United States)

    Roberts, Craig; Case, Sara; Reagoso, John; Webster, Cassandra

    2015-01-01

    The Deep Space Climate Observatory mission launched on February 11, 2015, and inserted onto a transfer trajectory toward a Lissajous orbit around the Sun-Earth L1 libration point. This paper presents an overview of the baseline transfer orbit and early mission maneuver operations leading up to the start of nominal science orbit operations. In particular, the analysis and performance of the spacecraft insertion, mid-course correction maneuvers, and the deep-space Lissajous orbit insertion maneuvers are discussed, com-paring the baseline orbit with actual mission results and highlighting mission and operations constraints..

  14. Skylab II - Seeing the sun in a different light. [mission equipment, experiments and observations

    Science.gov (United States)

    Green, W. D.

    1974-01-01

    The second Skylab mission continued the detailed investigation of man's interrelated physiological functions as they react to the novel situation of weightlessness in orbit. In general terms, the most important finding is that the increase in mission duration from 28 to 59 days failed to reveal any effects that would put a specific upper limit on the time that men can live in weightlessness. Observations of the sun during the second mission covered almost two full solar revolutions, yielding detailed data on the evolution of several active regions as they traversed the face of the sun, disappeared around the limb, then reappeared on the next cycle.

  15. Mission to the Gravitational Focus of the Sun: A Critical Analysis

    CERN Document Server

    Landis, Geoffrey A

    2016-01-01

    The gravitational field of the sun will focus light from a distant source to a focal point at a minimal distance of 500 Astronomical Units from the sun. A proposed mission to this gravitational focus could use the sun as a very large lens, allowing (in principle) a large amplification of signal from the target, and a very high magnification. This article discusses some of the difficulties involved in using the sun as such a gravitational telescope for a candidate mission, that of imaging the surface of a previously-detected exoplanet. These difficulties include the pointing and focal length, and associated high magnification; the signal to noise ratio associated with the solar corona, and the focal blur. In addition, a method to calculate the signal gain and magnification is derived using the first-order deflection calculation and classical optics, showing that the gain is finite for an on-axis source of non-zero area.

  16. The NASA EPOXI mission of opportunity to gather ultraprecise photometry of known transiting exoplanets

    CERN Document Server

    Christiansen, Jessie L; A'Hearn, Michael F; Deming, Drake; Holman, Matthew J; Ballard, Sarah; Weldrake, David T F; Barry, Richard K; Kuchner, Marc J; Livengood, Timothy A; Pedelty, Jeffrey; Schultz, Alfred; Hewagama, Tilak; Sunshine, Jessica M; Wellnitz, Dennis D; Hampton, Don L; Lisse, Carey M; Seager, Sara; Veverka, Joseph F

    2008-01-01

    The NASA Discovery mission EPOXI, utilizing the Deep Impact flyby spacecraft, comprises two phases: EPOCh (Extrasolar Planet Observation and Characterization) and DIXI (Deep Impact eXtended Investigation). With EPOCh, we use the 30-cm high resolution visible imager to obtain ultraprecise photometric light curves of known transiting planet systems. We will analyze these data for evidence of additional planets, via transit timing variations or transits; for planetary moons or rings; for detection of secondary eclipses and the constraint of geometric planetary albedos; and for refinement of the system parameters. Over a period of four months, EPOCh observed four known transiting planet systems, with each system observed continuously for several weeks. Here we present an overview of EPOCh, including the spacecraft and science goals, and preliminary photometry results.

  17. Orbit Determination Error Analysis Results for the Triana Sun-Earth L2 Libration Point Mission

    Science.gov (United States)

    Marr, G.

    2003-01-01

    Using the NASA Goddard Space Flight Center's Orbit Determination Error Analysis System (ODEAS), orbit determination error analysis results are presented for all phases of the Triana Sun-Earth L1 libration point mission and for the science data collection phase of a future Sun-Earth L2 libration point mission. The Triana spacecraft was nominally to be released by the Space Shuttle in a low Earth orbit, and this analysis focuses on that scenario. From the release orbit a transfer trajectory insertion (TTI) maneuver performed using a solid stage would increase the velocity be approximately 3.1 km/sec sending Triana on a direct trajectory to its mission orbit. The Triana mission orbit is a Sun-Earth L1 Lissajous orbit with a Sun-Earth-vehicle (SEV) angle between 4.0 and 15.0 degrees, which would be achieved after a Lissajous orbit insertion (LOI) maneuver at approximately launch plus 6 months. Because Triana was to be launched by the Space Shuttle, TTI could potentially occur over a 16 orbit range from low Earth orbit. This analysis was performed assuming TTI was performed from a low Earth orbit with an inclination of 28.5 degrees and assuming support from a combination of three Deep Space Network (DSN) stations, Goldstone, Canberra, and Madrid and four commercial Universal Space Network (USN) stations, Alaska, Hawaii, Perth, and Santiago. These ground stations would provide coherent two-way range and range rate tracking data usable for orbit determination. Larger range and range rate errors were assumed for the USN stations. Nominally, DSN support would end at TTI+144 hours assuming there were no USN problems. Post-TTI coverage for a range of TTI longitudes for a given nominal trajectory case were analyzed. The orbit determination error analysis after the first correction maneuver would be generally applicable to any libration point mission utilizing a direct trajectory.

  18. Sun

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    @@ Sun Microsystems, Inc. is committed to open standards,a standardization system, and sharing within the information tech nology field, focusing not only on technical innovation, but also on new ideas, practices and future development.

  19. Analysis of the flight dynamics of the Solar Maximum Mission (SMM) off-sun scientific pointing

    Science.gov (United States)

    Pitone, D. S.; Klein, J. R.; Twambly, B. J.

    1990-01-01

    Algorithms are presented which were created and implemented by the Goddard Space Flight Center's (GSFC's) Solar Maximum Mission (SMM) attitude operations team to support large-angle spacecraft pointing at scientific objectives. The mission objective of the post-repair SMM satellite was to study solar phenomena. However, because the scientific instruments, such as the Coronagraph/Polarimeter (CP) and the Hard X-ray Burst Spectrometer (HXRBS), were able to view objects other than the Sun, attitude operations support for attitude pointing at large angles from the nominal solar-pointing attitudes was required. Subsequently, attitude support for SMM was provided for scientific objectives such as Comet Halley, Supernova 1987A, Cygnus X-1, and the Crab Nebula. In addition, the analysis was extended to include the reverse problem, computing the right ascension and declination of a body given the off-Sun angles. This analysis led to the computation of the orbits of seven new solar comets seen in the field-of-view (FOV) of the CP. The activities necessary to meet these large-angle attitude-pointing sequences, such as slew sequence planning, viewing-period prediction, and tracking-bias computation are described. Analysis is presented for the computation of maneuvers and pointing parameters relative to the SMM-unique, Sun-centered reference frame. Finally, science data and independent attitude solutions are used to evaluate the larg-angle pointing performance.

  20. Analysis of the flight dynamics of the Solar Maximum Mission (SMM) off-sun scientific pointing

    Science.gov (United States)

    Pitone, D. S.; Klein, J. R.; Twambly, B. J.

    Algorithms are presented which were created and implemented by the Goddard Space Flight Center's (GSFC's) Solar Maximum Mission (SMM) attitude operations team to support large-angle spacecraft pointing at scientific objectives. The mission objective of the post-repair SMM satellite was to study solar phenomena. However, because the scientific instruments, such as the Coronagraph/Polarimeter (CP) and the Hard X-ray Burst Spectrometer (HXRBS), were able to view objects other than the Sun, attitude operations support for attitude pointing at large angles from the nominal solar-pointing attitudes was required. Subsequently, attitude support for SMM was provided for scientific objectives such as Comet Halley, Supernova 1987A, Cygnus X-1, and the Crab Nebula. In addition, the analysis was extended to include the reverse problem, computing the right ascension and declination of a body given the off-Sun angles. This analysis led to the computation of the orbits of seven new solar comets seen in the field-of-view (FOV) of the CP. The activities necessary to meet these large-angle attitude-pointing sequences, such as slew sequence planning, viewing-period prediction, and tracking-bias computation are described. Analysis is presented for the computation of maneuvers and pointing parameters relative to the SMM-unique, Sun-centered reference frame. Finally, science data and independent attitude solutions are used to evaluate the larg-angle pointing performance.

  1. Orbit Determination (OD) Error Analysis Results for the Triana Sun-Earth L1 Libration Point Mission and for the Fourier Kelvin Stellar Interferometer (FKSI) Sun-Earth L2 Libration Point Mission Concept

    Science.gov (United States)

    Marr, Greg C.

    2003-01-01

    The Triana spacecraft was designed to be launched by the Space Shuttle. The nominal Triana mission orbit will be a Sun-Earth L1 libration point orbit. Using the NASA Goddard Space Flight Center's Orbit Determination Error Analysis System (ODEAS), orbit determination (OD) error analysis results are presented for all phases of the Triana mission from the first correction maneuver through approximately launch plus 6 months. Results are also presented for the science data collection phase of the Fourier Kelvin Stellar Interferometer Sun-Earth L2 libration point mission concept with momentum unloading thrust perturbations during the tracking arc. The Triana analysis includes extensive analysis of an initial short arc orbit determination solution and results using both Deep Space Network (DSN) and commercial Universal Space Network (USN) statistics. These results could be utilized in support of future Sun-Earth libration point missions.

  2. Long Term Missions at the Sun-Earth Libration Point L1: ACE, SOHO, and WIND

    Science.gov (United States)

    Roberts, Craig E.

    2011-01-01

    Three heliophysics missions -- the Advanced Composition Explorer (ACE), Solar Heliospheric Observatory (SOHO), and the Global Geoscience WIND -- have been orbiting the Sun-Earth interior libration point L1 continuously since 1997, 1996, and 2004, respectively. ACE and WIND (both NASA missions) and SOHO (an ESA-NASA joint mission) are all operated from the NASA Goddard Space Flight Center (GSFC). While ACE and SOHO have been dedicated libration point orbiters since their launches, WIND has had also a remarkable 10-year career flying a deep-space, multiple lunar-flyby trajectory prior to 2004. That era featured 36 targeted lunar flybys with excursions to both L1 and L2 before its final insertion in L1 orbit. A figure depicts the orbits of the three spacecraft, showing projections of the orbits onto the orthographic planes of a solar rotating ecliptic frame of reference. The SOHO orbit is a quasi-periodic halo orbit, where the frequencies of the in-plane and out-of-plane motions are practically equal. Such an orbit is seen to repeat itself with a period of approximately 178 days. For ACE and WIND, the frequencies of the in-plane and out-of-plane motions are unequal, giving rise to the characteristic Lissajous motion. ACE's orbit is of moderately small amplitude, whereas WIND's orbit is a large-amplitude Lissajous of dimensions close to those of the SOHO halo orbit. As motion about the collinear points is inherently unstable, stationkeeping maneuvers are necessary to prevent orbital decay and eventual escape from the L1 region. Though the three spacecraft are dissimilar (SOHO is a 3-axis stabilized Sun pointer, WIND is a spin-stabilized ecliptic pole pointer, and ACE is also spin-stabilized with its spin axis maintained between 4 and 20 degrees of the Sun), the stationkeeping technique for the three is fundamentally the same. The technique consists of correcting the energy of the orbit via a delta-V directed parallel or anti-parallel to the Spacecraft-to-Sun line. SOHO

  3. Model for Cameron band emission in comets: A case for EPOXI mission target comet 103P/Hartley 2

    CERN Document Server

    Bhardwaj, Anil

    2010-01-01

    The CO2 production rate has been derived in comets using the Cameron band (a3Pi - X1Sigma) emission of CO molecule assuming that photodissociative excitation of CO2 is the main production mechanism of CO in a3Pi metastable state. We have devoloped a model for the production and loss of CO(a3Pi) which has been applied to comet 103P/Hartley 2: the target of EPOXI mission. Our model calculations show that photoelectron impact excitation of CO and dissociative excitation of CO2 can together contribute about 60-90% to the Cameron band emission. The modeled brightness of (0-0) Cameron band emission on comet Hartley 2 is consistent with Hubble Space Telescope observations for 3-5% CO2 (depending on model input solar flux) and 0.5% CO relative to water, where photoelectron impact contribution is about 50-75%. We suggest that estimation of CO2 abundances on comets using Cameron band emission may be reconsidered. We predict the height integrated column brightness of Cameron band of ~1300 R during EPOXI mission encounte...

  4. OBSERVATIONS OF INTENSITY FLUCTUATIONS ATTRIBUTED TO GRANULATION AND FACULAE ON SUN-LIKE STARS FROM THE KEPLER MISSION

    Energy Technology Data Exchange (ETDEWEB)

    Karoff, C. [Stellar Astrophysics Centre, Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, DK-8000 Aarhus C (Denmark); Campante, T. L. [Centro de Astrofisica and Faculdade de Ciencias, Universidade do Porto, Rua das Estrelas, 4150-762 Porto (Portugal); Ballot, J. [CNRS, Institut de Recherche en Astrophysique et Planetologie, 14 avenue Edouard Belin, F-31400, Toulouse (France); Kallinger, T. [Instituut voor Sterrenkunde, K. U. Leuven, Celestijnenlaan 200D, B-3001 Leuven (Belgium); Gruberbauer, M. [Institute for Computational Astrophysics, Department of Astronomy and Physics, Saint Mary' s University, B3H 3C3 Halifax (Canada); Garcia, R. A. [Laboratoire AIM, CEA/DSM-CNRS-Universit Paris Diderot, IRFU/SAp, Centre de Saclay, F-91191 Gif-sur-Yvette Cedex (France); Caldwell, D. A.; Christiansen, J. L. [SETI Institute/NASA Ames Research Center, Moffett Field, CA 94035 (United States); Kinemuchi, K., E-mail: karoff@phys.au.dk [Bay Area Environmental Research Inst./NASA Ames Research Center, Moffett Field, CA 94035 (United States)

    2013-04-10

    Sun-like stars show intensity fluctuations on a number of timescales due to various physical phenomena on their surfaces. These phenomena can convincingly be studied in the frequency spectra of these stars-while the strongest signatures usually originate from spots, granulation, and p-mode oscillations, it has also been suggested that the frequency spectrum of the Sun contains a signature of faculae. We have analyzed three stars observed for 13 months in short cadence (58.84 s sampling) by the Kepler mission. The frequency spectra of all three stars, as for the Sun, contain signatures that we can attribute to granulation, faculae, and p-mode oscillations. The temporal variability of the signatures attributed to granulation, faculae, and p-mode oscillations was analyzed and the analysis indicates a periodic variability in the granulation and faculae signatures-comparable to what is seen in the Sun.

  5. Preliminary Results on HAT-P-4, TrES-3, XO-2, and GJ 436 from the NASA EPOXI Mission

    CERN Document Server

    Ballard, Sarah; A'Hearn, Michael F; Deming, Drake; Holman, Matthew J; Christiansen, Jessie L; Weldrake, David T F; Barry, Richard K; Kuchner, Marc J; Livengood, Timothy A; Pedelty, Jeffrey; Schultz, Alfred; Hewagama, Tilak; Sunshine, Jessica M; Wellnitz, Dennis D; Hampton, Don L; Lisse, Carey M; Seager, Sara; Veverka, Joseph F

    2008-01-01

    EPOXI (EPOCh + DIXI) is a NASA Discovery Program Mission of Opportunity using the Deep Impact flyby spacecraft. The EPOCh (Extrasolar Planet Observation and Characterization) Science Investigation will gather photometric time series of known transiting exoplanet systems from January through August 2008. Here we describe the steps in the photometric extraction of the time series and present preliminary results of the first four EPOCh targets.

  6. High-Performance Data Analysis Tools for Sun-Earth Connection Missions

    Science.gov (United States)

    Messmer, Peter

    2011-01-01

    The data analysis tool of choice for many Sun-Earth Connection missions is the Interactive Data Language (IDL) by ITT VIS. The increasing amount of data produced by these missions and the increasing complexity of image processing algorithms requires access to higher computing power. Parallel computing is a cost-effective way to increase the speed of computation, but algorithms oftentimes have to be modified to take advantage of parallel systems. Enhancing IDL to work on clusters gives scientists access to increased performance in a familiar programming environment. The goal of this project was to enable IDL applications to benefit from both computing clusters as well as graphics processing units (GPUs) for accelerating data analysis tasks. The tool suite developed in this project enables scientists now to solve demanding data analysis problems in IDL that previously required specialized software, and it allows them to be solved orders of magnitude faster than on conventional PCs. The tool suite consists of three components: (1) TaskDL, a software tool that simplifies the creation and management of task farms, collections of tasks that can be processed independently and require only small amounts of data communication; (2) mpiDL, a tool that allows IDL developers to use the Message Passing Interface (MPI) inside IDL for problems that require large amounts of data to be exchanged among multiple processors; and (3) GPULib, a tool that simplifies the use of GPUs as mathematical coprocessors from within IDL. mpiDL is unique in its support for the full MPI standard and its support of a broad range of MPI implementations. GPULib is unique in enabling users to take advantage of an inexpensive piece of hardware, possibly already installed in their computer, and achieve orders of magnitude faster execution time for numerically complex algorithms. TaskDL enables the simple setup and management of task farms on compute clusters. The products developed in this project have the

  7. A Search for Additional Planets in Five of the Exoplanetary Systems Studied by the NASA EPOXI Mission

    CERN Document Server

    Ballard, Sarah; Charbonneau, David; Deming, Drake; Holman, Matthew J; A'Hearn, Michael F; Wellnitz, Dennis D; Barry, Richard K; Kuchner, Marc J; Livengood, Timothy A; Hewagama, Tilak; Sunshine, Jessica M; Hampton, Don L; Lisse, Carey M; Seager, Sara; Veverka, Joseph F

    2011-01-01

    We present time series photometry and constraints on additional planets in five of the exoplanetary systems studied by the EPOCh (Extrasolar Planet Observation and Characterization) component of the NASA EPOXI mission: HAT-P-4, TrES-3, TrES-2, WASP-3, and HAT-P-7. We conduct a search of the high-precision time series for photometric transits of additional planets. We find no candidate transits with significance higher than our detection limit. From Monte Carlo tests of the time series using putative periods from 0.5 days to 7 days, we demonstrate the sensitivity to detect Neptune-sized companions around TrES-2, sub-Saturn-sized companions in the HAT-P-4, TrES-3, and WASP-3 systems, and Saturn-sized companions around HAT-P-7. We investigate in particular our sensitivity to additional transits in the dynamically favorable 3:2 and 2:1 exterior resonances with the known exoplanets: if we assume coplanar orbits with the known planets, then companions in these resonances with HAT-P-4b, WASP-3b, and HAT-P-7b would b...

  8. A small mission concept to the Sun-Earth Lagrangian L5 point for innovative solar, heliospheric and space weather science

    Science.gov (United States)

    Lavraud, B.; Liu, Y.; Segura, K.; He, J.; Qin, G.; Temmer, M.; Vial, J.-C.; Xiong, M.; Davies, J. A.; Rouillard, A. P.; Pinto, R.; Auchère, F.; Harrison, R. A.; Eyles, C.; Gan, W.; Lamy, P.; Xia, L.; Eastwood, J. P.; Kong, L.; Wang, J.; Wimmer-Schweingruber, R. F.; Zhang, S.; Zong, Q.; Soucek, J.; An, J.; Prech, L.; Zhang, A.; Rochus, P.; Bothmer, V.; Janvier, M.; Maksimovic, M.; Escoubet, C. P.; Kilpua, E. K. J.; Tappin, J.; Vainio, R.; Poedts, S.; Dunlop, M. W.; Savani, N.; Gopalswamy, N.; Bale, S. D.; Li, G.; Howard, T.; DeForest, C.; Webb, D.; Lugaz, N.; Fuselier, S. A.; Dalmasse, K.; Tallineau, J.; Vranken, D.; Fernández, J. G.

    2016-08-01

    We present a concept for a small mission to the Sun-Earth Lagrangian L5 point for innovative solar, heliospheric and space weather science. The proposed INvestigation of Solar-Terrestrial Activity aNd Transients (INSTANT) mission is designed to identify how solar coronal magnetic fields drive eruptions, mass transport and particle acceleration that impact the Earth and the heliosphere. INSTANT is the first mission designed to (1) obtain measurements of coronal magnetic fields from space and (2) determine coronal mass ejection (CME) kinematics with unparalleled accuracy. Thanks to innovative instrumentation at a vantage point that provides the most suitable perspective view of the Sun-Earth system, INSTANT would uniquely track the whole chain of fundamental processes driving space weather at Earth. We present the science requirements, payload and mission profile that fulfill ambitious science objectives within small mission programmatic boundary conditions.

  9. CHANG'E-2 lunar escape maneuvers to the Sun-Earth L2 libration point mission

    Science.gov (United States)

    Liu, Lei; Liu, Yong; Cao, Jianfeng; Hu, Songjie; Tang, Geshi; Xie, Jianfeng

    2014-01-01

    This paper addresses lunar escape maneuvers of the first Chinese Sun-Earth L2 libration point mission by the CHANG'E-2 satellite, which is also the world's first satellite to reach the L2 point from a lunar orbit. The lunar escape maneuvers are heavily constrained by the remaining propellant and the condition of telemetry, track and command, among others. First, these constraints are analyzed and summarized to design a target L2 Lissajous orbit and an initial transfer trajectory. Second, the maneuver mathematical models are studied. The multilevel maneuver schemes which consist of phasing maneuvers and a final lunar escape maneuver are designed for actual operations. Based on the scheme analysis and comparison, the 2-maneuver scheme with a 5.3-h-period phasing orbit is ultimately selected. Finally, the mission status based on the scheme is presented and the control operation results are discussed in detail. The methodology in this paper is especially beneficial and applicable to a future multi-mission instance in the deep space exploration.

  10. Mission to the Sun-Earth L5 Lagrangian Point: An Optimal Platform for Space Weather Research

    Science.gov (United States)

    Vourlidas, Angelos

    2015-04-01

    The Sun-Earth Lagrangian L5 point is a uniquely advantageous location for space weather research and monitoring. It covers the "birth-to-impact" travel of solar transients; it enables imaging of solar activity at least 3 days prior to a terrestrial viewpoint and measures the solar wind conditions 4-5 days ahead of Earth impact. These observations, especially behind east limb magnetograms, will be a boon for background solar wind models, which are essential for coronal mass ejection (CME) and shock propagation forecasting. From an operational perspective, the L5 orbit is the space weather equivalent to the geosynchronous orbit for weather satellites. Optimal for both research and monitoring, an L5 mission is ideal for developing a Research-to-Operations capability in Heliophysics.

  11. Energetic Phenomena on the Sun: The Solar Maximum Mission Flare Workshop. Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    Kundu, M.; Woodgate, B.

    1986-12-01

    The general objectives of the conference were as follows: (1) Synthesize flare studies after three years of Solar Maximum Mission (SSM) data analysis. Encourage a broader participation in the SMM data analysis and combine this more fully with theory and other data sources-data obtained with other spacecraft such as the HINOTORI, p78-1, and ISEE-3 spacecrafts, and with the Very Large Array (VLA) and many other ground-based instruments. Many coordinated data sets, unprecedented in their breadth of coverage and multiplicity of sources, had been obtained within the structure of the Solar Maximum Year (SMY). (2) Stimulate joint studies, and publication in the general scientific literature. The intended primary benefit was for informal collaborations to be started or broadened at the Workshops with subsequent publications. (3) Provide a special publication resulting from the Workshop.

  12. A black sun in a white mind: In memory of Sudan mission 1848–1858

    Directory of Open Access Journals (Sweden)

    Marko Frelih

    2009-12-01

    Full Text Available Ignacij Knoblehar (1819–1858 worked as a Catholic missionary in southern Sudan, in particular among the Bari people. He sent regular reports home about his work and many newspapers also published his letters. Above all, he became known when he sailed beyond 4° north latitude. He was the first European to carry out systematic measurements of the White Nile and his discoveries were reported in both Europe and America. While he lived there, Slovenians became acquainted for the first time in their history with a part of Africa. In 1850 he brought a large collection of diverse artifacts from the Nilotic peoples back to Ljubljana. These artifacts are preserved in the Slovene Ethnographic Museum today, and part of the collection was put on display in a temporary exhibition entitled “Sudan Mission 1848–1858” at the museum in May 2009. The arrival of a number of African children in Ljubljana arguably constituted the highpoint of this early Slovenian contact with Africa. Missionaries bought the children at a slave market and brought them back to Europe with the intention of training the boys to be priests and the girls to be nuns. However, the plan fell through because the children all died of pneumonia and tuberculosis. The public baptism of the African children and the relationship of the general public to them in the mid-nineteenth century helped shape stereotypical representations of Africans as well as certain forms of racial discrimination that are still present today.

  13. Vision Algorithm for the Solar Aspect System of the High Energy Replicated Optics to Explore the Sun Mission

    Science.gov (United States)

    Cramer, Alexander Krishnan

    2014-01-01

    This work covers the design and test of a machine vision algorithm for generating high- accuracy pitch and yaw pointing solutions relative to the sun on a high altitude balloon. It describes how images were constructed by focusing an image of the sun onto a plate printed with a pattern of small cross-shaped fiducial markers. Images of this plate taken with an off-the-shelf camera were processed to determine relative position of the balloon payload to the sun. The algorithm is broken into four problems: circle detection, fiducial detection, fiducial identification, and image registration. Circle detection is handled by an "Average Intersection" method, fiducial detection by a matched filter approach, and identification with an ad-hoc method based on the spacing between fiducials. Performance is verified on real test data where possible, but otherwise uses artificially generated data. Pointing knowledge is ultimately verified to meet the 20 arcsecond requirement.

  14. Lissajous Orbit Control for the Deep Space Climate Observatory Sun-Earth L1 Libration Point Mission

    Science.gov (United States)

    Roberts, Craig; Case, Sarah; Reagoso, John

    2015-01-01

    DSCOVR Lissajous Orbit sized such that orbit track never extends beyond 15 degrees from Earth-Sun line (as seen from Earth). Requiring delta-V maneuvers, control orbit to obey a Solar Exclusion Zone (SEZ) cone of half-angle 4 degrees about the Earth-Sun line. Spacecraft should never be less than 4 degrees from solar center as seen from Earth. Following Lissajous Orbit Insertion (LOI), DSCOVR should be in an opening phase that just skirts the 4-degree SEZ. Maximizes time to the point where a closing Lissajous will require avoidance maneuvers to keep it out of the SEZ. Station keeping maneuvers should take no more than 15 minutes.

  15. Epoxy resins.

    Science.gov (United States)

    Bray, P G

    1999-01-01

    Epoxy resins have an extraordinarily broad range of commercial applications, especially as protective surface coatings and adhesives. Epoxy resin systems include combinations of epoxy monomers, hardeners, reactive diluents, and/or a vast array of other additives. As a result, an epoxy resin system may have a number of chemical ingredients with the potential for attendant health hazards. Most, but not all, of these health hazards arise in the occupational setting. The most frequent adverse effects are irritation or allergic mechanisms involving the dermal and respiratory systems. Sensitization usually is caused by low molecular weight or short-chain compounds. This review discusses the diagnosis, treatment, and prevention of epoxy resin-related adverse health effects.

  16. OH Fluorescence and Prompt Emission in comet 103P/Hartley 2 observed by EPOXI mission and expected results for comet 67P/Churyumov-Gerasimenko observed by Rosetta/OSIRIS WAC camera

    Science.gov (United States)

    La Forgia, F.; A'Hearn, M. F.; Lazzarin, M.; Magrin, S.; Bodewits, D.; Bertini, I.; Pajola, M.; Barbier, C.; Sierks, H.

    2014-04-01

    The OH radical, observed in cometary comae, is the direct dissociation product of water. Given the strong A2∑ - X2II (0, 0) emission band in the near-UV at 308.5 nm due to resonance fluorescence, the OH radical has been used, for years, as a tracer of the water parent molecule. Specifically, the OH fluorescence band provides an immediate tool to monitor the water production rate and its variations with the comet's heliocentric distance, rotational period and possible activity changes. Photolysis of water in cometary comae gives rise, with a non negligible branching ratio, to OH fragments in the first electronically excited state (OH*). This state is very unstable, with a lifetime of about 10-6s (Becker and Haaks, 1973), therefore OH* molecules promptly decay to the ground state. This process, generally referred to as prompt emission (PE), is responsible for an emission band in the near-UV ranging approximatelly from 306 to 325 nm. Original studies and tentative detections of OH PE have been put forth by Bertaux (1986), Budzien and Feldman (1991), Bonev et al. (2004), A'Hearn et al. (2007) using ground and space observations. Both from the above mentioned works together with our analysis, this process is expected to be prominent at short distances from the nucleus, where there is high density of water molecules, requiring the need of spacecraft observations to reach the necessary resolution. The hyperactive Jupiter family comet 103P/Hartley 2 has been visited by EPOXI spacecraft on 4 November 2010 at a minimum distance of 694 km, when it was at 1.064 AU from the Sun (A'Hearn et al. 2011). We present the analysis of photometric observations in OH filter acquired by MRI camera onboard EPOXI used to investigate the spatial distribution of OH in the coma of Hartley 2. The data revealed a radial OH structure within 35 km from the nucleus, appearing to be coming directly from the nucleus, in the region of the central waist. A theoretical computation evidencing a strong

  17. Cloud and Sun-Glint Statistics Derived from GOES and MODIS Observations Over the Intra-Americas Sea for GEO-CAPE Mission Planning

    Science.gov (United States)

    Feng, Lian; Hu, Chuanmin; Barnes, Brian B.; Mannino, Antonio; Heidinger, Andrew K.; Strabala, Kathleen; Iraci, Laura T.

    2017-01-01

    Knowledge of cloud cover, frequency, and duration is not only important to study cloud dynamics, but also critical in determining when and where to take ocean measurements from geostationary orbits such as the Geostationary Coastal and Air Pollution Events (GEO-CAPE) mission due to the challenges in achieving complete hemispheric coverage of coastal oceans, estuaries, and inland waters at hourly frequency. Using GOES hourly measurements at 4 km nadir resolution between 2006 and 2011, the number of cloud-free hourly observations per day (N(sub cf)) for solar zenith angle Theta(sub 0) less than 80 degrees was estimated for each 0.1 degree location of the Intra-Americas Sea. The number of Sun-glint-affected hourly observations per day [Ns(sub sg)] was also calculated based on the planned GEO-CAPE observation geometry and realistic wind speed. High-latitude and equatorial oceans showed the lowest N(sub cf) (less than 2.4) in all climatological months, and highest N(sub cf) was observed in the Gulf of Mexico (GoM) and Caribbean (greater than 4.5). Different regions showed differences in seasonality of cloud-free conditions and also showed differences in the hour of a day at which the satellite observations would have the maximal cloud-free and glint-free probability (Temperature maximum). Cloud cover from Moderate Resolution Imaging Spectroradiometer (MODIS) 1 km measurements are greater than 10 degrees higher than those from the MODIS 250 m measurements, supporting ocean color missions at subkilometer resolutions to enhance both spatial coverage and temporal frequency. These findings provide valuable information for GEO-CAPE mission planning to maximize its science value through minimizing the impacts of clouds and Sun glint.

  18. Epoxy sheathing

    National Research Council Canada - National Science Library

    1992-01-01

    ... their vessels using polyester resins. In May 1990, several fishermen applied to the Vessel Upgrading Program for assistance to fiberglass their vessels using epoxy resin for the purpose of extending fishing vessel life...

  19. Cloud and Sun-glint statistics derived from GOES and MODIS observations over the Intra-Americas Sea for GEO-CAPE mission planning

    Science.gov (United States)

    Feng, Lian; Hu, Chuanmin; Barnes, Brian B.; Mannino, Antonio; Heidinger, Andrew K.; Strabala, Kathleen; Iraci, Laura T.

    2017-02-01

    Knowledge of cloud cover, frequency, and duration is not only important to study cloud dynamics, but also critical in determining when and where to take ocean measurements from geostationary orbits such as the Geostationary Coastal and Air Pollution Events (GEO-CAPE) mission due to the challenges in achieving complete hemispheric coverage of coastal oceans, estuaries, and inland waters at hourly frequency. Using GOES hourly measurements at 4 km nadir resolution between 2006 and 2011, the number of cloud-free hourly observations per day (Ncf) for solar zenith angle θo oceans showed the lowest Ncf (4.5). Different regions showed differences in seasonality of cloud-free conditions and also showed differences in the hour of a day at which the satellite observations would have the maximal cloud-free and glint-free probability (Tmax). Cloud cover from Moderate Resolution Imaging Spectroradiometer (MODIS) 1 km measurements are >10% higher than those from the MODIS 250 m measurements, supporting ocean color missions at subkilometer resolutions to enhance both spatial coverage and temporal frequency. These findings provide valuable information for GEO-CAPE mission planning to maximize its science value through minimizing the impacts of clouds and Sun glint.

  20. Earth-Affecting Solar Causes Observatory (EASCO): A Potential International Living with a Star Mission from Sun-Earth L5

    Science.gov (United States)

    Gopalswamy, N.; Davila, J. M.; St Cyr, O. C.; Sittler, E. C.; Auchere, F.; Duvall, Jr. T. L.; Hoeksema, J. T.; Maksimovic, M.; MacDowall, R. J.; Szabo, A.; Collier, M. R.

    2011-01-01

    This paper describes the scientific rationale for an L5 mission and a partial list of key scientific instruments the mission should carry. The L5 vantage point provides an unprecedented view of the solar disturbances and their solar sources that can greatly advance the science behind space weather. A coronagraph and a heliospheric imager at L5 will be able to view CMEs broadsided, so space speed of the Earth-directed CMEs can be measured accurately and their radial structure discerned. In addition, an inner coronal imager and a magnetograph from L5 can give advance information on active regions and coronal holes that will soon rotate on to the solar disk. Radio remote sensing at low frequencies can provide information on shock-driving CMEs, the most dangerous of all CMEs. Coordinated helioseismic measurements from the Sun Earth line and L5 provide information on the physical conditions at the base of the convection zone, where solar magnetism originates. Finally, in situ measurements at L5 can provide information on the large-scale solar wind structures (corotating interaction regions (CIRs)) heading towards Earth that potentially result in adverse space weather.

  1. The Sun, Mercury, and Venus

    CERN Document Server

    Elkins-Tanton, Linda T

    2010-01-01

    The Messenger mission to Mercury opened a new window into the inner solar system. In 2008, this mission began a number of years of flybys, culminating in an orbital insertion around Mercury and producing unparalleled observations about this mysterious innermost planet. Mercury orbits so close to the Sun, from the point of view of Earth, that seeing it from the Earth against the Sun's glare is a great challenge. At the same time, the huge gravitational force of the Sun makes it a challenge to put a mission on Mercury without losing it into the Sun. Now, with heightened understanding of Mercury,

  2. Why Study the Sun?

    Indian Academy of Sciences (India)

    Arvind Bhatnagar

    2006-06-01

    In this presentation we briefly describe the Sun through large number of illustrations and pictures of the Sun taken from early times to the present day space missions. The importance of the study of the Sun is emphasized as it is the nearest star which presents unparallelled views of surface details and numerous phenomena. Our Sun offers a unique celestial laboratory where a large variety of phenomena take place, ranging in temporal domain from a few milliseconds to several decades, in spatial domain from a few hundred kilometers to thousands of kilometers, and in the temperature domain from a few thousand degrees to several million degrees. Its mass motion ranges from thousandths to thousands of kilometers per second. Such an object provides us with a unique laboratory to study the state of matter in the Universe. The existing solar ground-based and space missions have already revealed several mysteries of the outer environment of our Sun and much more is going to come in the near future from planned new sophisticated ground-based solar telescopes and Space missions. The new technique of helioseismology has unravelled many secrets of the solar interior and has put the Standard Solar Model (SSM) on firm footing. The long-standing problem of solar neutrinos has been recently sorted out, and even the ‘back side’ view of the Sun can be seen using the technique of holographic helioseismology.

  3. Attitude Determination and Control Subsystem (ADCS) Preparations for the EPOXI Flyby of Comet Haley 2

    Science.gov (United States)

    Luna, Michael E.; Collins, Stephen M.

    2011-01-01

    On November 4, 2010 the already "in-flight" Deep Impact spacecraft flew within 700km of comet 103P/Hartley 2 as part of its extended mission EPOXI, the 5th time to date any spacecraft visited a comet. In 2005, the spacecraft had previously imaged a probe impact comet Tempel 1. The EPOXI flyby marked the first time in history that two comets were explored with the same instruments on a re-used spacecraft-with hardware and software originally designed and optimized for a different mission. This made the function of the attitude determination and control subsystem (ADCS) critical to the successful execution of the EPOXI flyby. As part of the spacecraft team preparations, the ADCS team had to perform thorough sequence reviews, key spacecraft activities and onboard calibrations. These activities included: review of background sequences for the initial conditions vector, sun sensor coefficients, and reaction wheel assembly (RWA) de-saturations; design and execution of 10 trajectory correction maneuvers; science calibration of the two telescope instruments; a flight demonstration of the fastest turns conducted by the spacecraft between Earth and comet point; and assessment of RWA health (given RWA problems on other spacecraft).

  4. Attitude Determination and Control Subsystem (ADCS) Preparations for the EPOXI Flyby of Comet Haley 2

    Science.gov (United States)

    Luna, Michael E.; Collins, Stephen M.

    2011-01-01

    On November 4, 2010 the already "in-flight" Deep Impact spacecraft flew within 700km of comet 103P/Hartley 2 as part of its extended mission EPOXI, the 5th time to date any spacecraft visited a comet. In 2005, the spacecraft had previously imaged a probe impact comet Tempel 1. The EPOXI flyby marked the first time in history that two comets were explored with the same instruments on a re-used spacecraft-with hardware and software originally designed and optimized for a different mission. This made the function of the attitude determination and control subsystem (ADCS) critical to the successful execution of the EPOXI flyby. As part of the spacecraft team preparations, the ADCS team had to perform thorough sequence reviews, key spacecraft activities and onboard calibrations. These activities included: review of background sequences for the initial conditions vector, sun sensor coefficients, and reaction wheel assembly (RWA) de-saturations; design and execution of 10 trajectory correction maneuvers; science calibration of the two telescope instruments; a flight demonstration of the fastest turns conducted by the spacecraft between Earth and comet point; and assessment of RWA health (given RWA problems on other spacecraft).

  5. Epoxy resin

    Science.gov (United States)

    Wilson, Glenn R.; Salyer, Ival O.; Ball, III, George L.

    1976-07-13

    By mixing one part of a prepolymer containing a polyamine partially polymerized with an organic epoxide and subsequently reacted with a fatty acid containing from 8 to 32 carbon atoms, and then reacting this prepolymer mixture with 3 parts of an organic epoxide, a composition was obtained which made a gas frothable, shear-stable, room temperature curing, low density foam. A particularly advantageous prepolymer was prepared using a polyamine selected from the group consisting of diethylenetriamine, triethylenetetramine, and tetraethylenepentamine, partially polymerized with an organic epoxide having an average molecular weight of about 350 and having an epoxide equivalent of 185 to 192, and reacted with 2-10 weight percent linoleic acid. When one part of this prepolymer was reacted with about three parts of epoxy, and frothed by whipping in air or nitrogen an epoxy foam was produced which could be troweled onto surfaces and into corners or crevices, and subsequently cured, at near ambient temperature, to a strong dimensionally stable foam product.

  6. Sun Allergy

    Science.gov (United States)

    ... if you have unusual, bothersome skin reactions after exposure to sunlight. For severe or persistent symptoms, you may need ... m. when the sun is brightest. Avoid sudden exposure to lots of sunlight. Many people have sun allergy symptoms when they ...

  7. Evaluation of epoxy for use on NuSTAR optics

    DEFF Research Database (Denmark)

    An, H.; Christensen, Finn Erland; Doll, M.

    2009-01-01

    The Nuclear Spectroscopic Telescope Array (NuSTAR) is a NASA Small Explorer (SMEX) mission which employs two focusing optics. The optics are composed of stacks of thin mirror shells and spacers. Epoxy is used to bond the mirror shells to the spacers and is a crucial component in determining...... the structural and optical performance of the telescopes. We describe the epoxy selection for NuSTAR optics, emphasizing those epoxy characteristics essential to obtaining good optical performance....

  8. Radiation curing of epoxies

    Science.gov (United States)

    Dickson, Lawrence W.; Singh, Ajit

    The literature on radiation polymerization of epoxy compounds has been reviewed to assess the potential use of radiation for curing these industrially important monomers. Chemical curing of epoxies may proceed by either cationic or anionic mechanisms depending on the nature of the curing agent, but most epoxies polymerize by cationic mechanisms under the influence of high-energy radiation. Radiation-induced cationic polymerization of epoxy compounds is inhibited by trace quantities of water because of proton transfer from the chain-propagating epoxy cation to water. Several different methods with potential for obtaining high molecular weight polymers by curing epoxies with high-energy radiation have been studied. Polymeric products with epoxy-like properties have been produced by radiation curing of epoxy oligomers with terminal acrylate groups and mixtures of epoxies with vinyl monomers. Both of these types of resin have good potential for industrial-scale curing by radiation treatment.

  9. Sun-Earth Days

    Science.gov (United States)

    Thieman, J.; Ng, C.; Lewis, E.; Cline, T.

    2010-08-01

    Sun-Earth Day is a well-coordinated series of programs, resources and events under a unique yearly theme highlighting the fundamentals of heliophysics research and missions. A menu of activities, conducted throughout the year, inspire and educate participants. Sun-Earth Day itself can vary in date, but usually is identified by a celebration on or near the spring equinox. Through the Sun-Earth Day framework we have been able to offer a series of coordinated events that promote and highlight the Sun, its connection to Earth and the other planets. Sun-Earth Day events are hosted by educators, museums, amateur astronomers and scientists and occur at schools, community groups, parks, planetaria and science centers around the globe. Sun-Earth Day raises the awareness and knowledge of formal and informal education audiences concerning space weather and heliophysics. By building on the success of Sun-Earth Day yearly celebrations, we seek to affect people of all backgrounds and ages with the wonders of heliophysics science, discovery, and exploration in ways that are both tangible and meaningful to their lives.

  10. Attitude Determination and Control Subsystem (ADCS) Preparations for the EPOXI Flyby of Comet Hartley 2

    Science.gov (United States)

    Luna, Michael E.; Collins, Steven M.

    2011-01-01

    On November 4, 2010 the former "Deep Impact" spacecraft, renamed "EPOXI" for its extended mission, flew within 700km of comet 103P/Hartley 2. In July 2005, the spacecraft had previously imaged a probe impact of comet Tempel 1. The EPOXI flyby was the fifth close encounter of a spacecraft with a comet nucleus and marked the first time in history that two comet nuclei were imaged at close range with the same suite of onboard science instruments. This challenging objective made the function of the attitude determination and control subsystem (ADCS) critical to the successful execution of the EPOXI flyby.As part of the spacecraft flyby preparations, the ADCS operations team had to perform meticulous sequence reviews, implement complex spacecraft engineering and science activities and perform numerous onboard calibrations. ADCS contributions included design and execution of 10 trajectory correction maneuvers, the science calibration of the two telescopic instruments, an in-flight demonstration of high-rate turns between Earth and comet point, and an ongoing assessment of reaction wheel health. The ADCS team was also responsible for command sequences that included updates to the onboard ephemeris and sun sensor coefficients and implementation of reaction wheel assembly (RWA) de-saturations.

  11. Attitude Determination and Control Subsystem (ADCS) Preparations for the EPOXI Flyby of Comet Hartley 2

    Science.gov (United States)

    Luna, Michael E.; Collins, Steven M.

    2011-01-01

    On November 4, 2010 the former "Deep Impact" spacecraft, renamed "EPOXI" for its extended mission, flew within 700km of comet 103P/Hartley 2. In July 2005, the spacecraft had previously imaged a probe impact of comet Tempel 1. The EPOXI flyby was the fifth close encounter of a spacecraft with a comet nucleus and marked the first time in history that two comet nuclei were imaged at close range with the same suite of onboard science instruments. This challenging objective made the function of the attitude determination and control subsystem (ADCS) critical to the successful execution of the EPOXI flyby.As part of the spacecraft flyby preparations, the ADCS operations team had to perform meticulous sequence reviews, implement complex spacecraft engineering and science activities and perform numerous onboard calibrations. ADCS contributions included design and execution of 10 trajectory correction maneuvers, the science calibration of the two telescopic instruments, an in-flight demonstration of high-rate turns between Earth and comet point, and an ongoing assessment of reaction wheel health. The ADCS team was also responsible for command sequences that included updates to the onboard ephemeris and sun sensor coefficients and implementation of reaction wheel assembly (RWA) de-saturations.

  12. System parameters, transit times and secondary eclipse constraints of the exoplanet systems HAT-P-4, TrES-2, TrES-3 and WASP-3 from the NASA EPOXI Mission of Opportunity

    CERN Document Server

    Christiansen, Jessie L; Charbonneau, David; Deming, Drake; Holman, Matthew J; Madhusudhan, Nikku; Seager, Sara; Wellnitz, Dennis D; Barry, Richard K; Livengood, Timothy A; Hewagama, Tilak; Hampton, Don L; Lisse, Carey M; A'Hearn, Michael F

    2010-01-01

    As part of the NASA EPOXI Mission of Opportunity, we observed seven known transiting extrasolar planet systems in order to construct time series photometry of extremely high phase coverage and precision. Here we present the results for four "hot-Jupiter systems" with near-solar stars - HAT-P-4, TrES-3, TrES-2 and WASP-3. We observe ten transits of HAT-P-4, estimating the planet radius Rp = 1.332 \\pm 0.052 RJup, the stellar radius R \\star = 1.602 \\pm 0.061 R \\odot, the inclination i = 89.67 \\pm 0.30 degrees and the transit duration from first to fourth contact T = 255.6 \\pm 1.9 minutes. For TrES-3, we observe seven transits, and find Rp = 1.320 \\pm 0.057 RJup, R\\star = 0.817 \\pm 0.022 R\\odot, i = 81.99 \\pm 0.30 degrees and T = 81.9 \\pm 1.1 minutes. We also note a long term variability in the TrES-3 light curve, which may be due to star spots. We observe nine transits of TrES-2, and find Rp = 1.169 \\pm 0.034 RJup, R\\star = 0.940 \\pm 0.026 R\\odot, i = 84.15 \\pm 0.16 degrees and T = 107.3 \\pm 1.1 minutes. Finally...

  13. Aztec Suns

    Science.gov (United States)

    Petersen, Hugh

    2010-01-01

    The Aztec Sun Stone is a revered Mexican artifact. It is said to be perhaps the most famous symbol of Mexico, besides its flag. It primarily depicts the four great disasters that led to the migration of the Mexica people to modern-day Mexico City. The Aztec Sun Stone also contains pictographs depicting the way the Mexica measured time, and was…

  14. Aztec Suns

    Science.gov (United States)

    Petersen, Hugh

    2010-01-01

    The Aztec Sun Stone is a revered Mexican artifact. It is said to be perhaps the most famous symbol of Mexico, besides its flag. It primarily depicts the four great disasters that led to the migration of the Mexica people to modern-day Mexico City. The Aztec Sun Stone also contains pictographs depicting the way the Mexica measured time, and was…

  15. Sun L-Band Brightness Temperature Estimate from Soil Moisture and Ocean Salinity (SMOS) Mission: A Potential New Space Weather Applications for SMOS Data

    Science.gov (United States)

    Crapolicchio, Raffaele; Capolongo, Emiliano; Bigazzi, Alberto

    2016-08-01

    The paper presents the results of a validation study to assess the potentiality of the Level-1b (L1b) Soil Moisture and Ocean Salinity (SMOS) Sun Brightness Temperature (BT) as a valuable L-band radio signal useful in the space weather context. The validation exercise, done for both eruptive and quite/active Sun, focused on SMOS data availability, coverage and statistical analysis with respect to the United States Air Force (USAF) Radio Solar Telescope Network (RSTN) recorded data. In both cases the comparison of the two data sets has shown a strong timing correlation and an impressive burst amplitude correspondence. The paper also presents main advantages and some caveats in the use of the SMOS dataset. The results obtained encourage to pursue further studies both on the SMOS L1 processing algorithm refinement and on the usage of SMOS BT as an additional, independent and important source of information for space weather applications.

  16. Sun meter

    Science.gov (United States)

    Younskevicius, Robert E.

    1978-01-01

    A simple, inexpensive device for measuring the radiation energy of the sun impinging on the device. The measurement of the energy over an extended period of time is accomplished without moving parts or tracking mechanisms.

  17. The Sun

    CERN Document Server

    Golub, Leon

    2017-01-01

    Essential for life on earth and a major influence on our environment, the Sun is also the most fascinating object in the daytime sky. Every day we feel the effect of its coming and going – literally the difference between day and night. But figuring out what the Sun is, what it’s made of, why it glows so brightly, how old it is, how long it will last – all of these take thought and observation. Leon Golub and Jay M. Pasachoff offer an engaging and informative account of what scientists know about the Sun, and the history of these discoveries. Solar astronomers have studied the Sun over the centuries both for its intrinsic interest and in order to use it as a laboratory to reveal the secrets of other stars. The authors discuss the surface of the Sun, including sunspots and their eleven-year cycle, as well as the magnetism that causes them; the Sun’s insides, as studied mainly from seismic waves that astronomers record on its surface; the outer layers of the Sun that we see from Earth only at eclipses ...

  18. Midnight sun

    Energy Technology Data Exchange (ETDEWEB)

    Brunger, A.P.; Lambert, S.B.; Gagnon, M.P.

    1990-09-01

    Midnight Sun, the University of Waterloo's solar-electric car, was designed and built by about 30 engineering, kinesiology and physics students for the GM Sunrayce USA held in July 1990. The car measures 2 m by 4.2 m, weighs 224 kg, can collect about 1000 W of solar electricity in full sun, and had a top speed of 79 km/h. The race took 11 days to cover the 1644 miles from the Epcot Center in Lake Buena Vista, Florida to the GM Technical Center in Warren, Michigan. Thirty-two cars, powered only by solar energy, competed in this race. Midnight Sun showed its potential during the race qualifying runs by completing the required qualifying course with the 12th fastest time of 52.83 seconds, and the 6th fastest trap speed of 63 km/h. During the Sunrayce, Midnight Sun came in second on day 1 of the race, tenth on day 6, and eighth on day 7, and was one of only 17 solar cars that were able to make it up the toughest hill in the race on day 8. The most serious problems encountered by the car were a weak rear suspension, power losses, and failure of bypass diodes in the photovoltaic array. Midnight Sun was in 17th place overall at the end of day 9. At about 11:00 am on day 10 in Ohio, the Waterloo car was moving at 60 km/h when it was bumped off the road by an out of control pickup truck. The solar car driver was not hurt. Despite the difficulties, the next day Midnight Sun was repaired and driven across the finish line at the ceremonial finish. After receiving time penalties for not completing the last day and a half of the race, Midnight Sun was awarded 24th place with an official cumulative time of 114 h 37 min 15 s. 4 figs., 4 tabs.

  19. Flame Retardant Epoxy Resins

    Science.gov (United States)

    Thompson, C. M.; Smith, J. G., Jr.; Connell, J. W.; Hergenrother, P. M.; Lyon, R. E.

    2004-01-01

    As part of a program to develop fire resistant exterior composite structures for future subsonic commercial aircraft, flame retardant epoxy resins are under investigation. Epoxies and their curing agents (aromatic diamines) containing phosphorus were synthesized and used to prepare epoxy formulations. Phosphorus was incorporated within the backbone of the epoxy resin and not used as an additive. The resulting cured epoxies were characterized by thermogravimetric analysis, propane torch test, elemental analysis and microscale combustion calorimetry. Several formulations showed excellent flame retardation with phosphorous contents as low as 1.5% by weight. The fracture toughness of plaques of several cured formulations was determined on single-edge notched bend specimens. The chemistry and properties of these new epoxy formulations are discussed.

  20. Little Sun

    DEFF Research Database (Denmark)

    Ebbesen, Toke Riis

    2017-01-01

    the ideas of Alfred Gell’s anthropology of art and the indicative framework derived from Argentinian semiotician Juan Pablo Bonta and Jørn Guldberg. The toy-like solar lamp Little Sun by Olafur Eliasson and Frederik Ottesen is used as case that blends the registers of social design and art......, and as an example of how designers attempt to determine meaning potentials through design in a complex interplay of different strategies. In the final analysis, what characterise objects like Little Sun is seldom that they communicate their meanings in themselves, but instead rely on forceful mediations to gain...

  1. Little sun

    DEFF Research Database (Denmark)

    Ebbesen, Toke Riis

    2017-01-01

    the ideas of Alfred Gell’s anthropology of art and the indicative framework derived from Argentinian semiotician Juan Pablo Bonta and Jørn Guldberg. The toy-like solar lamp Little Sun by Olafur Eliasson and Frederik Ottesen is used as case that blends the registers of social design and art......, and as an example of how designers attempt to determine meaning potentials through design in a complex interplay of different strategies. In the final analysis, what characterise objects like Little Sun is seldom that they communicate their meanings in themselves, but instead rely on forceful mediations to gain...

  2. Navigation of the EPOXI Spacecraft to Comet Hartley 2

    Science.gov (United States)

    Bhaskaran, Shyam; Abrahamson, Matt; Chesley, Steven; Chung, Min-Kun; Halsell, Allen; Haw, Robert; Helfrich, Cliff; Jefferson, David; Kennedy, Brian; McElrath, Tim; Owen, William; Rush, Brian; Smith, Jonathon; Wang, Tseng-Chan; Yen, Chen-Wan

    2011-01-01

    On November 4, 2010, the EPOXI spacecraft flew by the comet Hartley 2, marking the fourth time that a NASA spacecraft successfully captured high resolution images of a cometary nucleus. EPOXI is the extended mission of the Deep Impact mission, which delivered an impactor on comet Tempel-1 on July 4, 2005. EPOXI officially started in September 2007 and eventually took over 3 years of flight time and had 3 Earth gravity assists to achieve the proper encounter conditions. In the process, the mission was redesigned to accommodate a new comet as the target and changes in the trajectory to achieve better imaging conditions at encounter. Challenges in navigation of the spacecraft included precision targeting of several Earth flybys and the comet encounter, uncertainties in determining the ephemeris of the comet relative to the spacecraft, and the high accuracy trajectory knowledge needed to image the comet during the encounter. This paper presents an overview of the navigation process used for the mission.

  3. Sun Proof

    Centers for Disease Control (CDC) Podcasts

    2012-10-23

    In this podcast for kids, the Kidtastics talk about the harmful effects of the sun and how to protect yourself from it.  Created: 10/23/2012 by Centers for Disease Control and Prevention (CDC).   Date Released: 10/23/2012.

  4. Epoxy + liquid crystalline epoxy coreacted network

    Science.gov (United States)

    Punchaipetch, Prakaipetch

    2000-10-01

    Molecular reinforcement through in-situ polymerization of liquid crystalline epoxies (LCEs) and a non-liquid crystalline epoxy has been investigated. Three LCEs: diglycidyl ether of 4,4'-dihydroxybiphenol (DGE-DHBP) and digylcidyl ether of 4-hydroxyphenyl-4″-hydroxybiphenyl-4 '-carboxylate (DGE-HHC), were synthesized and blended with diglycidyl ether of bisphenol F (DGEBP-F) and subsequently cured with anhydride and amine curing agents. Curing kinetics were determined using differential scanning calorimetry (DSC). Parameters for autocatalytic curing kinetics of both pure monomers and blended systems were determined. The extent of cure for both monomers was monitored by using Fourier transform infrared spectroscopy (FT-IR). The glass transitions were evaluated as a function of composition using DSC and dynamic mechanical analysis (DMA). The results show that the LC constituent affects the curing kinetics of the epoxy resin and that the systems are highly miscible. The effects of molecular reinforcement of DGEBP-F by DGE-DHBP and DGE-HHC were investigated. The concentration of the liquid crystalline moiety affects mechanical properties. Tensile, impact and fracture toughness tests results are evaluated. Scanning electron microscopy of the fracture surfaces shows changes in failure mechanisms compared to the pure components. Results indicate that mechanical properties of the blended samples are improved already at low concentration by weight of the LCE added into epoxy resin. The improvement in mechanical properties was found to occur irrespective of the absence of liquid crystallinity in the blended networks. The mechanism of crack study indicates that crack deflection and crack bridging are the mechanisms in case of LC epoxy. In case of LC modified epoxy, the crack deflection is the main mechanism. Moreover, the effect of coreacting an epoxy with a reactive monomer liquid crystalline epoxy as a matrix for glass fiber composites was investigated. Mechanical

  5. Epoxy Adhesives for Stator Magnet Assembly in Stirling Radioisotope Generators (SRG)

    Science.gov (United States)

    Cater, George M.

    2004-01-01

    As NASA seeks to fulfill its goals of exploration and understanding through missions planned to visit the moons of Saturn and beyond, a number of challenges arise from the idea of deep space flight. One of the first problems associated with deep space travel is electrical power production for systems on the spacecraft. Conventional methods such as solar power are not practical because efficiency decreases substantially as the craft moves away from the Sun. The criterion for power generation during deep space missions are very specific, the main points requiring high reliability, low mass, minimal vibration and a long lifespan. A Stirling generator, although fairly old in concept, is considered to be a potential solution for electrical power generation for deep space flight. A Stirling generator works on the same electromagnetic principles of a standard generator, using the linear motion of the alternator through the stationary stator which produces electric induction. The motion of the alternator, however, is produced by the heating and cooling dynamics of pressurized gases. Essentially heating one end and cooling another of a contained gas will cause a periodic expansion and compression of the gas from one side to the other, which a displacer translates into linear mechanical motion. NASA needs to confirm that the materials used in the generator will be able to withstand the rigors of space and the life expectancy of the mission. I am working on the verification of the epoxy adhesives used to bond magnets to the steel lamination stack to complete the stator; in terms of in-service performance and durability under various space environments. Understanding the proper curing conditions, high temperature properties, and degassing problems as well as production difficulties are crucial to the long term success of the generator. system and steel substrate used in the stator. To optimize the curing conditions of the epoxies, modulated differential scanning calorimetry

  6. RESEARCH ON IMPROVED EPOXY RESINS.

    Science.gov (United States)

    another ’million-modulus’ epoxy resin. Cast resin properties from a series of epoxy resins hardened with several aromatic diamines are reported, but these data are sufficient to advance only speculative conclusions. (Author)

  7. Ra: The Sun for Science and Humanity

    Science.gov (United States)

    1996-01-01

    To guide the development of the Ra Strategic Framework, we defined scientific and applications objectives. For our primary areas of scientific interest, we choose the corona, the solar wind, the Sun's effect on the Earth, and solar theory and model development. For secondary areas of scientific interest, we selected sunspots, the solar constant, the Sun's gravitational field, helioseismology and the galactic cosmic rays. We stress the importance of stereoscopic imaging, observations at high spatial, spectral, and temporal resolutions, as well as of long duration measurements. Further exploration of the Sun's polar regions is also important, as shown already by the Ulysses mission. From an applications perspective, we adopted three broad objectives that would derive complementary inputs for the Strategic Framework. These were to identify and investigate: possible application spin-offs from science missions, possible solar-terrestrial missions dedicated to a particular application, and possible future applications that require technology development. The Sun can be viewed as both a source of resources and of threats. Our principal applications focus was that of threat mitigation, by examining ways to improve solar threat monitoring and early warning systems. We compared these objectives to the mission objectives of past, current, and planned international solar missions. Past missions (1962-1980) seem to have been focused on improvement of scientific knowledge, using multiple instrument spacecraft. A ten year gap followed this period, during which the results from previous missions were analyzed and solar study programmes were prepared in international organizations. Current missions (1990-1996) focus on particular topics such as the corona, solar flares, and coronal mass ejections. In planned missions, Sun/Earth interactions and environmental effects of solar activity are becoming more important. The corona is the centre of interest of almost all planned missions

  8. Cobalt ion-containing epoxies

    Science.gov (United States)

    Stoakley, D. M.; St.clair, A. K.

    1983-01-01

    Varying concentrations of an organometallic cobalt complex were added to an epoxy system currently used by the aerospace industry as a composite matrix resin. Methods for combining cobalt (III) acetylacetonate with a tetraglycidyl 4,4 prime - diaminodiphenylmethane-based epoxy were investigated. The effects of increasing cobalt ion concentration on the epoxy cure were demonstrated by epoxy gel times and differential scanning calorimetry cure exotherms. Analysis on cured cobalt-containing epoxy castings included determination of glass transition temperatures by thermomechanical analysis, thermooxidative stabilities by thermogravimetric analysis, and densities in a density gradient column. Flexural strength and stiffness were also measured on the neat resin castings.

  9. The STEREO Mission

    CERN Document Server

    2008-01-01

    The STEREO mission uses twin heliospheric orbiters to track solar disturbances from their initiation to 1 AU. This book documents the mission, its objectives, the spacecraft that execute it and the instruments that provide the measurements, both remote sensing and in situ. This mission promises to unlock many of the mysteries of how the Sun produces what has become to be known as space weather.

  10. NEW SUNS IN THE COSMOS?

    Energy Technology Data Exchange (ETDEWEB)

    De Freitas, D. B.; Leao, I. C.; Lopes, C. E. Ferreira; Paz-Chinchon, F.; Canto Martins, B. L.; Alves, S.; De Medeiros, J. R. [Departamento de Fisica, Universidade Federal do Rio Grande do Norte, 59072-970 Natal, RN (Brazil); Catelan, M. [Departamento de Astronomia y Astrofisica, Pontificia Universidad Catolica de Chile, Av. Vicuna Mackenna 4860, 782-0436 Macul, Santiago (Chile)

    2013-08-20

    The present work reports on the discovery of three stars that we have identified to be rotating Sun-like stars, based on rotational modulation signatures inferred from light curves from the CoRoT mission's Public Archives. In our analysis, we performed an initial selection based on the rotation period and position in the period-T{sub eff} diagram. This revealed that the stars CoRoT IDs 100746852, 102709980, and 105693572 provide potentially good matches to the Sun with a similar rotation period. To refine our analysis, we applied a novel procedure, taking into account the fluctuations of the features associated with photometric modulation at different time intervals and the fractality traces that are present in the light curves of the Sun and of these ''New Sun'' candidates alike. In this sense, we computed the so-called Hurst exponent for the referred stars, for a sample of 14 CoRoT stars with sub- and super-solar rotational periods, and for the Sun itself in its active and quiet phases. We found that the Hurst exponent can provide a strong discriminant of Sun-like behavior, going beyond what can be achieved with solely the rotation period itself. In particular, we find that CoRoT ID 105693572 is the star that most closely matches the solar rotation properties as far as the latter's imprints on light curve behavior are concerned. The stars CoRoT IDs 100746852 and 102709980 have significant smaller Hurst exponents than the Sun, notwithstanding their similarity in rotation periods.

  11. Contact allergy to epoxy hardeners.

    Science.gov (United States)

    Aalto-Korte, Kristiina; Suuronen, Katri; Kuuliala, Outi; Henriks-Eckerman, Maj-Len; Jolanki, Riitta

    2014-09-01

    Diglycidylether of bisphenol A resin is the most important sensitizer in epoxy systems, but a minority of patients develop concomitant or solitary contact allergy to epoxy hardeners. At the Finnish Institute of Occupational Health, several in-house test substances of epoxy hardeners have been tested in a special epoxy compound patch test series. To analyse the frequency and clinical relevance of allergic reactions to different epoxy hardeners. Test files (January 1991 to March 2013) were screened for contact allergy to different epoxy hardeners, and the clinical records of patients with allergic reactions were analysed for occupation, concomitant allergic reactions, and exposure. The most commonly positive epoxy hardeners were m-xylylenediamine (n = 24), 2,4,6-tris-(dimethylaminomethyl)phenol (tris-DMP; n = 14), isophorone-diamine (n = 12), and diethylenetriamine (n = 9). Trimethylhexamethylenediamine (n = 7), tetraethylenepentamine (n = 4), and triethylenetetramine (n = 2) elicited some reactions, although most patients were found to have no specific exposure. Allergic reactions to hexamethylenetetramine, dimethylaminopropylamine and ethylenediamine dihydrochloride were not related to epoxy products. Tris-DMP is an important sensitizer in epoxy hardeners, and should be included in the patch test series of epoxy chemicals. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  12. SunPy—Python for solar physics

    Science.gov (United States)

    SunPy Community; Mumford, Stuart J.; Christe, Steven; Pérez-Suárez, David; Ireland, Jack; Shih, Albert Y.; Inglis, Andrew R.; Liedtke, Simon; Hewett, Russell J.; Mayer, Florian; Hughitt, Keith; Freij, Nabil; Meszaros, Tomas; Bennett, Samuel M.; Malocha, Michael; Evans, John; Agrawal, Ankit; Leonard, Andrew J.; Robitaille, Thomas P.; Mampaey, Benjamin; Campos-Rozo, Jose Iván; Kirk, Michael S.

    2015-01-01

    This paper presents SunPy (version 0.5), a community-developed Python package for solar physics. Python, a free, cross-platform, general-purpose, high-level programming language, has seen widespread adoption among the scientific community, resulting in the availability of a large number of software packages, from numerical computation (NumPy, SciPy) and machine learning (scikit-learn) to visualization and plotting (matplotlib). SunPy is a data-analysis environment specializing in providing the software necessary to analyse solar and heliospheric data in Python. SunPy is open-source software (BSD licence) and has an open and transparent development workflow that anyone can contribute to. SunPy provides access to solar data through integration with the Virtual Solar Observatory (VSO), the Heliophysics Event Knowledgebase (HEK), and the HELiophysics Integrated Observatory (HELIO) webservices. It currently supports image data from major solar missions (e.g., SDO, SOHO, STEREO, and IRIS), time-series data from missions such as GOES, SDO/EVE, and PROBA2/LYRA, and radio spectra from e-Callisto and STEREO/SWAVES. We describe SunPy's functionality, provide examples of solar data analysis in SunPy, and show how Python-based solar data-analysis can leverage the many existing tools already available in Python. We discuss the future goals of the project and encourage interested users to become involved in the planning and development of SunPy.

  13. Process for epoxy foam production

    Science.gov (United States)

    Celina, Mathias C [Albuquerque, NM

    2011-08-23

    An epoxy resin mixture with at least one epoxy resin of between approximately 60 wt % and 90 wt %, a maleic anhydride of between approximately 1 wt % and approximately 30 wt %, and an imidazole catalyst of less than approximately 2 wt % where the resin mixture is formed from at least one epoxy resin with a 1-30 wt % maleic anhydride compound and an imidazole catalyst at a temperature sufficient to keep the maleic anhydride compound molten, the resin mixture reacting to form a foaming resin which can then be cured at a temperature greater than 50.degree. C. to form an epoxy foam.

  14. Sun and Sun Worship in Different Cultures

    Science.gov (United States)

    Farmanyan, S. V.; Mickaelian, A. M.

    2014-10-01

    The Sun symbol is found in many cultures throughout history, it has played an important role in shaping our life on Earth since the dawn of time. Since the beginning of human existence, civilisations have established religious beliefs that involved the Sun's significance to some extent. As new civilisations and religions developed, many spiritual beliefs were based on those from the past so that there has been an evolution of the Sun's significance throughout cultural development. For comparing and finding the origin of the Sun we made a table of 66 languages and compared the roots of the words. For finding out from where these roots came from, we also made a table of 21 Sun Gods and Goddesses and proved the direct crossing of language and mythology.

  15. Occupational exposure to epoxy resins

    NARCIS (Netherlands)

    Terwoert, J.; Kersting, K.

    2014-01-01

    Products based on epoxy resins as a binder have become popular in various settings, among which the construction industry and in windmill blade production, as a result of their excellent technical properties. However, due to the same properties epoxy products are a notorious cause of allergic skin d

  16. Occupational exposure to epoxy resins

    NARCIS (Netherlands)

    Terwoert, J.; Kersting, K.

    2014-01-01

    Products based on epoxy resins as a binder have become popular in various settings, among which the construction industry and in windmill blade production, as a result of their excellent technical properties. However, due to the same properties epoxy products are a notorious cause of allergic skin

  17. Sun's rap song

    Science.gov (United States)

    Hogan, M.; Lee, W.

    1995-07-01

    We present a rap song composed for the Sun, our star. This Sun's Rap Song can be utilized in classroom teaching to spark the students' interest and facilitate the students' learning of the relevant subjects.

  18. MedSun Reports

    Data.gov (United States)

    U.S. Department of Health & Human Services — The Medical Product Safety Network (MedSun) is an adverse event reporting program launched in 2002. The primary goal for MedSun is to work collaboratively with the...

  19. MedSun Reports

    Data.gov (United States)

    U.S. Department of Health & Human Services — The Medical Product Safety Network (MedSun) is an adverse event reporting program launched in 2002. The primary goal for MedSun is to work collaboratively with the...

  20. EPOXY RESIN TOUGHENED BY THERMOPLASTICS

    Institute of Scientific and Technical Information of China (English)

    FU Zengli; SUN Yishi

    1989-01-01

    Two kinds of tough ductile heatresisting thermoplastic, namely bisphenol A polysulfone (PSF) and polyethersulfone (PES) were used to toughen thermoset epoxy resin. A systematic study on the relationship between the molecular weight and the terminal group of the thermoplastic modifier and the fracture toughness of the modified resin was carried out. The morphology of PSF modified epoxy resin was surveyed. With the same kind of PSF the structure of the epoxy resin and the toughening effect of PSF was also investigated. The fractography of PSF, particle modified epoxy was examined in detail with SEM. The contribution of every possible energy absorption process has been discussed. Crack pinning mechanism seems to be the most important toughening mechanism for tough ductile thermoplastic PSF particle modified epoxy system.

  1. Curing Behavior of Epoxy Asphalt

    Institute of Scientific and Technical Information of China (English)

    YU Jianying; CONG Peiliang; WU Shaopeng; CHENG Songbo

    2009-01-01

    The curing process of epoxy asphalt was analyzed by Fourier transform infrared (FT-IR)spectroscopy.Effect of curing temperature on viscosity of epoxy asphalt,and changes of mechanical properties with curing time were investigated.The evolution of concentration of epoxy band was followed as a function of the applied curing process.The experimental results indicate that the curing reaction rate of epoxy asphalt is invariable before 70 min at 120℃,and it decreases when curing time exceeds 70 min.The viscosity of epoxy asphalt increases slowly with curing time at initial curing stage.But it increases quickly after initial curing stage and the initial curing time decreases as the curing temperature increases.The tensile strength increases slowly at incipient curing stage and increases rapidly when curing time is form 20 min to 70 min.The elongation at break shows a decrease with curing time,but it exceeds 200%after cured.

  2. Interaction of water with epoxy.

    Energy Technology Data Exchange (ETDEWEB)

    Powers, Dana Auburn

    2009-07-01

    The chemistries of reactants, plasticizers, solvents and additives in an epoxy paint are discussed. Polyamide additives may play an important role in the absorption of molecular iodine by epoxy paints. It is recommended that the unsaturation of the polyamide additive in the epoxy cure be determined. Experimental studies of water absorption by epoxy resins are discussed. These studies show that absorption can disrupt hydrogen bonds among segments of the polymers and cause swelling of the polymer. The water absorption increases the diffusion coefficient of water within the polymer. Permanent damage to the polymer can result if water causes hydrolysis of ether linkages. Water desorption studies are recommended to ascertain how water absorption affects epoxy paint.

  3. Seasons by the Sun

    Science.gov (United States)

    Stark, Meri-Lyn

    2005-01-01

    Understanding the Sun has challenged people since ancient times. Mythology from the Greek, Inuit, and Inca cultures attempted to explain the daily appearance and nightly disappearance of the Sun by relating it to a chariot being chased across the sky. While people no longer believe the Sun is a chariot racing across the sky, teachers are still…

  4. Personal, Seasonal Suns

    Science.gov (United States)

    Sutley, Jane

    2010-01-01

    This article presents an art project designed for upper-elementary students to (1) imagine visual differences in the sun's appearance during the four seasons; (2) develop ideas for visually translating their personal experiences regarding the seasons to their sun drawings; (3) create four distinctive seasonal suns using colors and imagery to…

  5. The Apsidal Precession for Low Earth Sun Synchronized Orbits

    Directory of Open Access Journals (Sweden)

    Shkelzen Cakaj

    2015-09-01

    Full Text Available By nodal regression and apsidal precession, the Earth flattering at satellite low Earth orbits (LEO is manifested. Nodal regression refers to the shift of the orbit’s line of nodes over time as Earth revolves around the Sun. Nodal regression is orbit feature utilized for circular orbits to be Sun synchronized. A sun¬-synchronized orbit lies in a plane that maintains a fixed angle with respect to the Earth-Sun direction. In the low Earth Sun synchronized circular orbits are suited the satellites that accomplish their photo imagery missions. Nodal regression depends on orbital altitude and orbital inclination angle. For the respective orbital altitudes the inclination window for the Sun synchronization to be attained is determined. The apsidal precession represents major axis shift, respectively the argument of perigee deviation. The apsidal precession simulation, for inclination window of sun synchronized orbital altitudes, is provided through this paper.

  6. Contact allergy to epoxy resin

    DEFF Research Database (Denmark)

    Bangsgaard, Nannie; Thyssen, Jacob Pontoppidan; Menné, Torkil

    2012-01-01

    . Objectives. To evaluate the prevalence of contact allergy to epoxy resin monomer (diglycidyl ether of bisphenol A; MW 340) among patients with suspected contact dermatitis and relate this to occupation and work-related consequences. Patients/methods. The dataset comprised 20 808 consecutive dermatitis...... in an educational programme. Conclusion. The 1% prevalence of epoxy resin contact allergy is equivalent to reports from other countries. The high occurrence of epoxy resin exposure at work, and the limited use of protective measures, indicate that reinforcement of the law is required....

  7. The Ulysses mission: An introduction

    Energy Technology Data Exchange (ETDEWEB)

    Marsden, R.G. [Space Science Dept. of ESA, Estec, Noordwijk (Netherlands)

    1996-11-01

    On 30 September 1995, Ulysses completed its initial, highly successful, survey of the polar regions of the heliosphere in both southern and northern hemispheres, thereby fulfilling its prime mission. The results obtained to date are leading to a revision of many earlier ideas concerning the solar wind and the heliosphere. Now embarking on the second phase of the mission, Ulysses will continue along its out-of-ecliptic flight path for another complete orbit of the Sun. In contrast to the high-latitude phase of the prime mission, which occurred near solar minimum, the next polar passes (in 2000 and 2001) will take place when the Sun is at its most active.

  8. Epoxy hydantoins as matrix resins

    Science.gov (United States)

    Weiss, J.

    1983-01-01

    Tensile strength and fracture toughness of castings of the hydantoin resins cured with methylenedianiline are significantly higher than MY 720 control castings. Water absorption of an ethyl, amyl hydantoin formulation is 2.1 percent at equilibrium and Tg's are about 160 C, approximately 15 deg below the final cure temperature. Two series of urethane and ester-extended hydantoin epoxy resins were synthesized to determine the effect of crosslink density and functional groups on properties. Castings cured with methylenedianiline or with hexahydrophthalic anhydride were made from these compounds and evaluated. The glass transition temperatures, tensile strengths and moduli, and fracture toughness values were all much lower than that of the simple hydantoin epoxy resins. Using a methylene bishydantoin epoxy with a more rigid structure gave brittle, low-energy fractures, while a more flexible, ethoxy-extended hydantoin epoxy resin gave a very low Tg.

  9. Synthesis of polyoxometalate-loaded epoxy composites

    Science.gov (United States)

    Anderson, Benjamin J

    2014-10-07

    The synthesis of a polyoxometalate-loaded epoxy uses a one-step cure by applying an external stimulus to release the acid from the polyoxometalate and thereby catalyze the cure reaction of the epoxy resin. Such polyoxometalate-loaded epoxy composites afford the cured epoxy unique properties imparted by the intrinsic properties of the polyoxometalate. For example, polyoxometalate-loaded epoxy composites can be used as corrosion resistant epoxy coatings, for encapsulation of electronics with improved dielectric properties, and for structural applications with improved mechanical properties.

  10. SunPy: Solar Physics in Python

    Science.gov (United States)

    Ryan, Daniel; Christe, Steven; Mumford, Stuart; Perez Suarez, David; Ireland, Jack; Shih, Albert Y.; Inglis, Andrew; Liedtke, Simon; Hewett, Russel

    2015-04-01

    SunPy is a community-developed open-source software library for solar physics. It is written in Python, a free, cross-platform, general-purpose, high-level programming language which is being increasingly adopted throughout the scientific community as well as further afield. This has resulted in a wide array of software packages useful for scientific computing, from numerical computation (NumPy, SciPy, etc.), to machine learning (scifitlearn), to visualization and plotting (matplotlib). SunPy aims to provide required specialised software for analysing solar and heliospheric datasets in Python. The current version is 0.5 with 0.6 expected to be released later this year. SunPy provides solar data access through integration with the Virtual Solar Observatory (VSO), the Heliophysics Event Knowledgebase (HEK), and the HELiophysics Integrated Observatory (HELIO) webservices. It supports common data types from major solar missions such as images (SDO/AIA, STEREO, PROBA2/SWAP etc.), time series (GOES/XRS, SDO/EVE, PROBA2/LYRA), and radio spectra (e-Callisto, STEREO/WAVES). SunPy’s code base is publicly available through github.com and can be contributed to by anyone. In this poster we demonstrate SunPy’s functionality and future goals of the project. We also encourage interested users to become involved in further developing SunPy.

  11. Paramagnetic epoxy resin

    Directory of Open Access Journals (Sweden)

    E. C. Vazquez Barreiro

    2017-01-01

    Full Text Available This work illustrates that macrocycles can be used as crosslinking agents for curing epoxy resins, provided that they have appropriate organic functionalities. As macrocycles can complex metal ions in their structure, this curing reaction allows for the introduction of that metal ion into the resin network. As a result, some characteristic physical properties of the metallomacrocycle could be transferred to the new material. The bisphenol A diglycidyl ether (BADGE, n = 0 and hemin (a protoporphyrin IX containing the Fe(III ion, and an additional chloride ligand have been chosen. The new material has been characterized by differential scanning calorimetry (DSC, thermogravimetric analysis (TGA, Fourier Transform Infrared (FT-IR, Nuclear Magnetic Resonance (NMR, Transmission Electron Microscopy (TEM, and magnetic susceptibility measurements. Fe(III remains in the high-spin state during the curing process and, consequently, the final material exhibits the magnetic characteristics of hemin. The loss of the chlorine atom ligand during the cure of the resin allows that Fe(III can act as Lewis acid, catalyzing the crosslinking reactions. At high BADGE n = 0/hemin ratios, the formation of ether and ester bonds occurs simultaneously during the process.

  12. The Prisma Hyperspectra Mission

    Science.gov (United States)

    Loizzo, R.; Ananasso, C.; Guarini, R.; Lopinto, E.; Candela, L.; Pisani, A. R.

    2016-08-01

    PRISMA (PRecursore IperSpettrale della Missione Applicativa) is an Italian Space Agency (ASI) hyperspectral mission currently scheduled for the lunch in 2018. PRISMA is a single satellite placed on a sun- synchronous Low Earth Orbit (620 km altitude) with an expected operational lifetime of 5 years. The hyperspectral payload consists of a high spectral resolution (VNIR-SWIR) imaging spectrometer, optically integrated with a medium resolution Panchromatic camera. PRISMA will acquire data on areas of 30 km Swath width and with a Ground Sampling Distance (GSD) of 30 m (hyperspectral) and of 5 m Panchromatic (PAN). The PRISMA Ground Segment will be geographically distributed between Fucino station and ASI Matera Space Geodesy Centre and will include the Mission Control Centre, the Satellite Control Centre and the Instrument Data Handling System. The science community supports the overall lifecycle of the mission, being involved in algorithms definition, calibration and validation activities, research and applications development.

  13. Sun and Sjogren's Syndrome

    Science.gov (United States)

    Patient Education Sheet The Sun and Sjögren’s Syndrome The SSF thanks Mona Z. Mofid, MD, FAAD, Diplomate, American Board of Dermatology, and Medical Director, American Melanoma Foundation, San Diego, California, ...

  14. The Sun and Earth

    Science.gov (United States)

    Gopalswamy, Natchimuthuk

    2012-01-01

    Thus the Sun forms the basis for life on Earth via the black body radiation it emits. The Sun also emits mass in the form of the solar wind and the coronal mass ejections (CMEs). Mass emission also occurs in the form of solar energetic particles (SEPs), which happens during CMEs and solar flares. Both the mass and electromagnetic energy output of the Sun vary over a wide range of time scales, thus introducing disturbances on the space environment that extends from the Sun through the entire heliosphere including the magnetospheres and ionospheres of planets and moons of the solar system. Although our habitat is located in the neutral atmosphere of Earth, we are intimately connected to the non-neutral space environment starting from the ionosphere to the magnetosphere and to the vast interplanetary space. The variability of the solar mass emissions results in the interaction between the solar wind plasma and the magnetospheric plasma leading to huge disturbances in the geospace. The Sun ionizes our atmosphere and creates the ionosphere. The ionosphere can be severely disturbed by the transient energy input from solar flares and the solar wind during geomagnetic storms. The complex interplay between Earth's magnetic field and the solar magnetic field carried by the solar wind presents varying conditions that are both beneficial and hazardous to life on earth. This seminar presents some of the key aspects of this Sun-Earth connection that we have learned since the birth of space science as a scientific discipline some half a century ago.

  15. The sun and space weather Second Edition

    CERN Document Server

    Hanslmeier, Arnold

    2007-01-01

    This second edition is a great enhancement of literature which will help the reader get deeper into the specific topics. There are new sections included such as space weather data sources and examples, new satellite missions, and the latest results. At the end a comprehensive index is given which will allow the reader to quickly find his topics of interest. The Sun and Space weather are two rapidly evolving topics. The importance of the Sun for the Earth, life on Earth, climate and weather processes was recognized long ago by the ancients. Now, for the first time there is a continuous surveillance of solar activity at nearly all wavelengths. These data can be used to improve our understanding of the complex Sun-Earth interaction. The first chapters of the book deal with the Sun as a star and its activity phenomena as well as its activity cycle in order to understand the complex physics of the Sun-Earth system. The reader will see that there are many phenomena but still no definite explanations and models exis...

  16. Damping Properties of Flexible Epoxy Resin

    Institute of Scientific and Technical Information of China (English)

    WANG Xiang; LIU Hanxing; OUYANG Shixi

    2008-01-01

    Amino-terminated polyethers and amino-terminated polyurethane were used as curing agent to cure the epoxy resin together and get a series of cured products. The damping properties of the composites were studied by DMA test at different measurement frequencies. Damping mechanical tests show that the flexible epoxy resin has higher loss factor than common epoxy. The highest loss factor reaches 1.57. Also the height and position of loss factor peak of the flexible epoxy resin varies by changing the content of amino-terminated polyethers. Results shows that the flexible epoxy resin can be used as damping polymer materials at room temperature or in common frequency range.

  17. [Epoxy resin systems and contact dermatitis].

    Science.gov (United States)

    Pietranek, Jolanta Eliza

    2007-01-01

    Contact dermatitis is the major chronic skin disease that represents a global health problem. Its prevalence has been significant increasing in the latest decades. Contact dermatitis substantially alters the social life of patients and affects their work productivity. Epoxy resin systems are a frequent cause of occupational allergic contact dermatitis. Epoxy resins have an extremely wide range of commercial applications. Epoxy resin systems include combinations of epoxy monomers, hardeners, reactive diluents, and/or a vast array of other additives. In occupational settings, sensitization occurs not only to resins, but also to hardeners and reactive diluents. In this article adverse effects of epoxy resin systems are discussed.

  18. Tailoring of epoxy material properties

    NARCIS (Netherlands)

    Nakka, J.S.

    2010-01-01

    This research work is aimed to understand the effect of resin chemistry on the physical properties (e.g. moduli, viscoelasticity, moisture uptake, coefficient of thermal expansion) of cured aromatic epoxy-amine thermoset resins. This understanding will result into a good first approximation of the f

  19. Lessons from the Sun

    Directory of Open Access Journals (Sweden)

    Robitaille P.-M.

    2011-07-01

    Full Text Available In this brief note, the implications of a condensed Sun will be examined. A celestial body composed of liquid metallic hydrogen brings great promise to astronomy, relative to understanding thermal emission and solar structure. At the same time, as an incom- pressible liquid, a condensed Sun calls into question virtually everything which is cur- rently believed with respect to the evolution and nature of the stars. Should the Sun be condensed, then neutron stars and white dwarfs will fail to reach the enormous densities they are currently believed to possess. Much of cosmology also falls into question, as the incompressibility of matter curtails any thought that a primordial atom once existed. Aging stars can no longer collapse and black holes will know no formative mechanism. A condensed Sun also hints that great strides must still be made in understanding the nature of liquids. The Sun has revealed that liquids possess a much greater potential for lattice order than previously believed. In addition, lessons may be gained with regards to the synthesis of liquid metallic hydrogen and the use of condensed matter as the basis for initiating fusion on Earth.

  20. Magnetohydrodynamics of the sun

    CERN Document Server

    Priest, Eric

    2014-01-01

    Magnetohydrodynamics of the Sun is a completely new up-to-date rewrite from scratch of the 1982 book Solar Magnetohydrodynamics, taking account of enormous advances in understanding since that date. It describes the subtle and complex interaction between the Sun's plasma atmosphere and its magnetic field, which is responsible for many fascinating dynamic phenomena. Chapters cover the generation of the Sun's magnetic field by dynamo action, magnetoconvection and the nature of photospheric flux tubes such as sunspots, the heating of the outer atmosphere by waves or reconnection, the structure of prominences, the nature of eruptive instability and magnetic reconnection in solar flares and coronal mass ejections, and the acceleration of the solar wind by reconnection or wave-turbulence. It is essential reading for graduate students and researchers in solar physics and related fields of astronomy, plasma physics and fluid dynamics. Problem sets and other resources are available at www.cambridge.org/9780521854719.

  1. The Sun's Supergranulation

    CERN Document Server

    Rieutord, Michel

    2010-01-01

    The Sun's supergranulation refers to a physical pattern covering the surface of the quiet Sun with a typical horizontal scale of approximately 30000km. Its most noticeable observable signature is as a fluctuating velocity field whose components are mostly horizontal. Supergranulation was discovered more than fifty years ago, however explaining why and how it originates still represents one of the main challenges of modern solar physics. A lot of work has been devoted to the subject over the years, but observational constraints, conceptual difficulties and numerical limitations have all concurred to prevent a detailed understanding of the supergranulation phenomenon so far. With the advent of 21st century supercomputing resources and the availability of unprecedented high-resolution observations of the Sun, the solar community has now reached a stage at which key progress can be made on this question. A unifying strategy between observations and modeling is more than ever required for this to be possible. The ...

  2. Sun, Earth and Sky

    Science.gov (United States)

    Lang, Kenneth R.

    1995-01-01

    The Sun is enveloped by a hot, tenuous million-degree corona that expands to create a continuous solar wind that sweeps past all the planets and fills the heliosphere. The solar wind is modulated by strong gusts that are initiated by powerful explosions on the Sun, including solar flares and coronal mass ejections. This dynamic, invisible outer atmosphere of the Sun is currently under observation with the soft X-ray telescope aboard the Yohkoh spacecraft, whose results are presented. We also show observations from the Ulysses spacecraft that is now passing over the solar pole, sampling the solar wind in this region for the first time. Two other spacecraft, Voyager 1 and 2, have recently detected the outer edge of the invisible heliosphere, roughly halfway to the nearest star. Magnetic solar activity, the total radiative output from the Sun, and the Earth's mean global surface temperature all vary with the 11-year sunspot cycle in which the total number of sunspots varies from a maximum to a minimum and back to a maximum again in about 11 years. The terrestrial magnetic field hollows out a protective magnetic cavity, called the magnetosphere, within the solar wind. This protection is incomplete, however, so the Sun feeds an unseen world of high-speed particles and magnetic fields that encircle the Earth in space. These particles endanger spacecraft and astronauts, and also produce terrestrial aurorae. An international flotilla of spacecraft is now sampling the weak points in this magnetic defense. Similar spacecraft have also discovered a new radiation belt, in addition to the familiar Van Allen belts, except fed by interstellar ions instead of electrons and protons from the Sun.

  3. Neptune as a Mirror for the Sun

    Science.gov (United States)

    Kohler, Susanna

    2017-01-01

    How would the Kepler mission see a star like the Sun? We now know the answer to this question due to a creative approach: a new study has used the Kepler K2 mission to detect signals from the Sun reflected off of the surface of Neptune.Asteroseismology uses different oscillation modes of a star to probe its internal structure and properties. [Tosaka]Information in OscillationsKeplers most glamorous work is in discovering new planets around other stars. To successfully do this, however, the spacecraft is also quietly doing a lot of very useful work in the background, characterizing the many stars in our vicinity that planets might be found around.One of the ways Kepler gets information about these stars is from oscillations of the stars intensities. In asteroseismology, we look at oscillatory modes that are caused by convection-driven pressure changes on the inside of the star. All stars with near-surface convection oscillate like this including the Sun and by measuring the oscillations in intensity of these stars, we can make inferences about the stars properties.A Planetary MirrorWe do this by first understanding our Suns oscillations especially well (made easier by the fact that its nearby!). Then we use asteroseimic scaling relations determined empirically that relate characteristics like mass and radius of other stars to those of the Sun, based on the relation between the stars oscillation properties to the Suns.The trouble is, those oscillation properties are difficult to measure, and different instruments often measure different values. For this reason, wed like to measure the Suns oscillations with the same instrument we use to measure other stars oscillations: Kepler.Top panel: Kepler K2 49-day light curve of Neptune. Bottom panel: power density spectrum as a function of frequency (grey). Neptunes rotation frequencies and harmonics appear toward the left side (blue); the excess power due to the solar modes is visible toward the bottom right. The green curve

  4. Piece of the sun

    CERN Document Server

    Wayne, Teddy

    2015-01-01

    Our rapidly industrialising world has an insatiable hunger for energy, and conventional sources are struggling to meet demand. Oil is running out, coal is damaging our climate, many nations are abandoning nuclear, yet solar, wind and water will never be a complete replacement. The solution, says Daniel Clery in this deeply researched and revelatory book, is to be found in the original energy source: the Sun itself. There, at its centre, the fusion of 630 million tonnes of hydrogen every second generates an unfathomable amount of energy. By replicating even a tiny piece of the Sun's power

  5. Near-Sun asteroids

    Science.gov (United States)

    Emel'yanenko, V. V.

    2017-01-01

    As follows from dynamical studies, in the course of evolution, most near-Earth objects reach orbits with small perihelion distances. Changes of the asteroids in the vicinity of the Sun should play a key role in forming the physical properties, size distribution, and dynamical features of the near-Earth objects. Only seven of the discovered asteroids are currently moving along orbits with perihelion distances q orbits farther from the Sun. In this study, we found asteroids that have been recently orbiting with perihelion distances q orbits for hundreds to tens of thousands of years. To carry out astrophysical observations of such objects is a high priority.

  6. The SUN S TRAVELS

    Institute of Scientific and Technical Information of China (English)

    Robert; Louis; Stevenson

    2005-01-01

    The sun is not a-bed, when I At night upon my pillow lie; Stilt round the earth his Way he takes, And morning after morning makes. White here at home, in shining day, We round the sunny garden play, Each tittle Indian sleepy - head Is being kissed and put to bed. And When at eve I rise from tea, Day dawns beyond the Atlantic Sea; And all the children in the West Are getting up and being dressed.The SUN'S TRAVELS@Robert Louis Stevenson

  7. The PROBA-3 Mission

    Science.gov (United States)

    Zhukov, Andrei

    2016-07-01

    PROBA-3 is the next ESA mission in the PROBA line of small technology demonstration satellites. The main goal of PROBA-3 is in-orbit demonstration of formation flying techniques and technologies. The mission will consist of two spacecraft together forming a giant (150 m long) coronagraph called ASPIICS (Association of Spacecraft for Polarimetric and Imaging Investigation of the Corona of the Sun). The bigger spacecraft will host the telescope, and the smaller spacecraft will carry the external occulter of the coronagraph. ASPIICS heralds the next generation of solar coronagraphs that will use formation flying to observe the inner corona in eclipse-like conditions for extended periods of time. The occulter spacecraft will also host the secondary payload, DARA (Davos Absolute RAdiometer), that will measure the total solar irradiance. PROBA-3 is planned to be launched in 2019. The scientific objectives of PROBA-3 will be discussed in the context of other future solar and heliospheric space missions.

  8. Effect of epoxy resin properties on the mechanical properties of carbon fiber/epoxy resin composites

    Energy Technology Data Exchange (ETDEWEB)

    He, Hong-Wei; Gao, Feng [Taiyuan Univ. of Technology (China). College of Materials Science and Engineering; Taiyuan Univ. of Technology (China). Key Laboratory of Interface Science and Engineering in Advanced Materials; Li, Kai-Xi [Chinese Academy of Sciences, Taiyuan, Shanxi (China). Key Laboratory of Carbon Materials

    2013-09-15

    Three kinds of epoxy resins, i.e. tetraglycidyl diaminodiphenyl methane (AG80), difunctional diglycidyl ether of bisphenol-A (E51) and novolac type epoxy resin (F46) were selected as matrices for carbon fiber/epoxy composites. The objective of this work is to study the mechanical properties of fiber/epoxy composites by using these three kinds of epoxy resins with different physical and chemical performance. The results show that the composites fabricated with AG80 present the best stiffness and the composites prepared with E5 1have the best toughness. The stiffness and toughness of the composites prepared with F46 are middle values located between those for AG80/epoxy and E51/epoxy composites. Thus, the mixed epoxy resin is a promising approach for industrial production. (orig.)

  9. Maximising the sun

    CSIR Research Space (South Africa)

    Conradie, Dirk CU

    2010-08-01

    Full Text Available South Africa is blessed with some of the best quality solar radiation in the world. In the light of this many exciting opportunities exist to utilize the sun to its full potential in the design of energy efficient buildings. Passive solar buildings...

  10. Sun Ultra 5

    CERN Multimedia

    1998-01-01

    The Sun Ultra 5 is a 64-bit personal computer based on the UltraSPARC microprocessor line at a low price. The Ultra 5 has been declined in several variants: thus, some models have a processor with less cache memory to further decrease the price of the computer.

  11. The Toboggan Sun

    NARCIS (Netherlands)

    Davidson, WPS; van der Werf, SY

    2005-01-01

    Special variants of the Novaya Zemlya effect may arise from localized temperature inversions that follow the height profile of hills or mountains. Rather than following its natural path, the rising or setting Sun may, under such circumstances, appear to slide along a distant mountain slope. We found

  12. Go Sun Smart

    Science.gov (United States)

    Scott, Michael D.; Buller, David B.; Walkosz, Barbara J.; Andersen, Peter A.; Cutter, Gary R.; Dignan, Mark B.

    2008-01-01

    This is the story of Go Sun Smart, a worksite wellness program endorsed by the North American Ski Area Association and funded by the National Cancer Institute. Between 2000 and 2002 we designed and implemented a large-scale worksite intervention at over 300 ski resorts in North America with the objective of reducing ski area employees and guests…

  13. Sun, Earth and Sky

    CERN Document Server

    Lang, Kenneth R

    2006-01-01

    This Second Edition of Sun, Earth and Sky updates the popular text by providing comprehensive accounts of the most recent discoveries made by five modern solar spacecraft during the past decade. Their instruments have used sound waves to peer deep into the Sun’s inner regions and measure the temperature of its central nuclear reactor, and extended our gaze far from the visible Sun to record energetic outbursts that threaten Earth. Breakthrough observations with the underground Sudbury Neutrino Observatory are also included, which explain the new physics of ghostly neutrinos and solve the problematic mismatch between the predicted and observed amounts of solar neutrinos. This new edition of Sun, Earth and Sky also describes our recent understanding of how the Sun’s outer atmosphere is heated to a million degrees, and just where the Sun’s continuous winds come from. As humans we are more intimately linked with our life-sustaining Sun than with any other astronomical object, and the new edition therefore p...

  14. Our Explosive Sun

    Science.gov (United States)

    Brown, D. S.

    2009-01-01

    The Sun's atmosphere is a highly structured but dynamic place, dominated by the solar magnetic field. Hot charged gas (plasma) is trapped on lines of magnetic force that can snap like an elastic band, propelling giant clouds of material out into space. A range of ground-based and space-based solar telescopes observe these eruptions, particularly…

  15. JPL Mission Design Software: Current Efforts to Support Low-Cost Missions

    Science.gov (United States)

    Fordyce, J.

    1994-01-01

    Over the last several decades, engineers at the Jet Propulsion Laboratory have developed a collection of analytical tools to design missions to Earth orbit, the moon, sun, planets and various other bodies in our solar system, and beyond.

  16. 日地平动点卫星两脉冲转移轨道设计%Two impulses transfer trajectory design for Sun-Earth libration point missions

    Institute of Scientific and Technical Information of China (English)

    李明涛; 郑建华; 于锡峥; 高东

    2009-01-01

    Two impulses transfer trajectory design based on the least differential corrections method was studied, differential correction equation with the altitude and the flight path angle constraints was concluded, and the convergence of the method was discussed. Halo orbit around the L_1 libration point of the Sun-Earth system was taken as the objective orbit, two impulses transfer trajectory was designed in the framework of the circular restricted three-body problem. Effect of Halo orbit insertion (HOI) point and amplitude was studied in a systematic way, a strategy for the selection of HOI point was given, and the fast transfer trajectory for e-mergency was also studied. Numerical simulation shows that the proposed method is very effective, and transfer trajectory with moderate flight time can be obtained by choosing points on the near Earth side of Halo orbit as HOI point.%研究基于最小二乘微分修正方法的平动点卫星两脉冲转移轨道设计,推导了考虑高度和航迹角约束的微分修正公式,讨论了该方法的收敛性.以日地L_1点附近的Halo轨道为目标轨道,在圆型限制性三体问题模型下设计了其转移轨道,系统地研究了HOI(Halo Orbit Insertion)点和Halo轨道幅值对转移轨道的影响,给出了HOI点的选择策略,并讨论了应急情况下快速转移轨道设计.数值仿真验证了方法的有效性,选择Halo轨道靠近地球侧的点作HOI点可以获得飞行时间适中的转移轨道.

  17. Flammability of Epoxy Resins Containing Phosphorus

    Science.gov (United States)

    Hergenrother, P. M.; Thompson, C. M.; Smith, J. G.; Connell, J. W.; Hinkley, J. A.

    2005-01-01

    As part of a program to develop fire-resistant exterior composite structures for future subsonic commercial and general aviation aircraft, flame-retardant epoxy resins are under investigation. Epoxies and their curing agents (aromatic diamines) containing phosphorus were synthesized and used to prepare epoxy formulations. Phosphorus was incorporated within the backbone of the epoxy resin and not used as an additive. The resulting cured neat epoxy formulations were characterized by thermogravimetric analysis, propane torch test, elemental analysis, microscale combustion calorimetry, and fire calorimetry. Several formulations showed excellent flame retardation with phosphorous contents as low as 1.5% by weight. The fracture toughness and compressive strength of several cured formulations showed no detrimental effect due to phosphorus content. The chemistry and properties of these new epoxy formulations are discussed.

  18. Epoxy resins in the construction industry.

    Science.gov (United States)

    Spee, Ton; Van Duivenbooden, Cor; Terwoert, Jeroen

    2006-09-01

    Epoxy resins are used as coatings, adhesives, and in wood and concrete repair. However, epoxy resins can be highly irritating to the skin and are strong sensitizers. Some hardeners are carcinogenic. Based on the results of earlier Dutch studies, an international project on "best practices,"--Epoxy Code--with epoxy products was started. Partners were from Denmark, Germany, the Netherlands, and the UK. The "Code" deals with substitution, safe working procedures, safer tools, and skin protection. The feasibility of an internationally agreed "ranking system" for the health risks of epoxy products was studied. Such a ranking system should inform the user of the harmfulness of different epoxies and stimulate research on less harmful products by product developers.

  19. Shelf Stable Epoxy Repair Adhesive

    Science.gov (United States)

    2015-02-01

    manufacturing operations are more efficient , discarding less expired film. Commercial and military aircraft repair operations at Boeing experience very similar...successfully encapsulated at concentrations greater than 50 wt% within four N N = CC Infoscitex Corporation Shelf Stable Epoxy Resin Adhesive WP-1763 8...affects the composition of the encapsulant , which in turn affects the ability of the encapsulant to wet the core phase, the barrier properties of the

  20. Graphite/Epoxy Deicing Heater

    Science.gov (United States)

    Hung, Ching-Cheh; Dillehay, Michael E.; Stahl, Mark

    1988-01-01

    Heat applied close to surface protected. One ply of highly electrically- and thermally-conductive brominated-graphite fiber composite laminated between two plies of electrically-insulating composite material, with michel foil making contact with end portions of graphite fibers. Part of foil exposed beyond composite to serve as electrical contact. Graphite/Epoxy composite heater developed to prevent and reverse formation of ice on advanced composite surfaces of aircraft.

  1. SunPy - Python for Solar Physics

    CERN Document Server

    Community, The SunPy; Christe, Steven; Pérez-Suárez, David; Ireland, Jack; Shih, Albert Y; Inglis, Andrew R; Liedtke, Simon; Hewett, Russell J; Mayer, Florian; Hughitt, Keith; Freij, Nabil; Meszaros, Tomas; Bennett, Samuel M; Malocha, Michael; Evans, John; Agrawal, Ankit; Leonard, Andrew J; Robitaille, Thomas P; Mampaey, Benjamin; Campos-Rozo, Jose Iván; Kirk, Michael S

    2015-01-01

    This paper presents SunPy (version 0.5), a community-developed Python package for solar physics. Python, a free, cross-platform, general-purpose, high-level programming language, has seen widespread adoption among the scientific community, resulting in the availability of a large number of software packages, from numerical computation (NumPy, SciPy) and machine learning (scikit-learn) to visualisation and plotting (matplotlib). SunPy is a data-analysis environment specialising in providing the software necessary to analyse solar and heliospheric data in Python. SunPy is open-source software (BSD licence) and has an open and transparent development workflow that anyone can contribute to. SunPy provides access to solar data through integration with the Virtual Solar Observatory (VSO), the Heliophysics Event Knowledgebase (HEK), and the HELiophysics Integrated Observatory (HELIO) webservices. It currently supports image data from major solar missions (e.g., SDO, SOHO, STEREO, and IRIS), time-series data from mis...

  2. Mechanical Properties of Heavy Duty Epoxy Coatings

    OpenAIRE

    Reinoso Rodríguez, Rosa

    2013-01-01

    In a first stage, the composition of epoxy coatings is discussed with special focus on the mechanism of curing and the chemistry of curing agents and their advantages and downturns in prospect to their use in the manufacture of epoxy resins. Then literature on the causes of increased brittleness, cracking and degradation of epoxy resins was studied, especially in relation to evolution of the resins in the glassy state, hydrothermal aging and also in relation to chemical aging. ...

  3. Functionalization of nanodiamond with epoxy monomer

    Institute of Scientific and Technical Information of China (English)

    Huan Huan Zhang; Ya Ting Liu; Rong Wang; Xiao Yan Yu; Xiong Wei Qu; Qing Xin Zhang

    2011-01-01

    A novel nanodiamond-epoxy derivative (ND-EP) was synthesized by grafting epoxy monomers onto the surface of nanodiamond (ND), and characterized by FTIR and TGA. The ratio of grafted epoxy groups was determined to be 32.5 wt% by TGA. The developed methodology provides an efficient method for the functionalization of nanodiamond material, which enables a variety of advanced engineering and biomedical applications of ND.

  4. Epoxy Resins Modified with Vegetable Oils

    Institute of Scientific and Technical Information of China (English)

    P.Czub

    2007-01-01

    1 Results The application of modified natural oils, nontoxic, biodegradable and renewable materials, for the modification and the synthesis of epoxy resins were presented. Firstly, the application of epoxidized vegetable oils (soybean, rapeseed, linseed and sunflower):as reactive diluents for epoxy resins was proposed and studied[1-2]. Viscosity reducing ability of epoxidized oils was tested in the compositions with Bisphenol A based low-molecular-weight epoxy resins. The rheological behaviour of the mi...

  5. Thermally activated, single component epoxy systems

    KAUST Repository

    Unruh, David A.

    2011-08-23

    A single component epoxy system in which the resin and hardener components found in many two-component epoxies are combined onto the same molecule is described. The single molecule precursor to the epoxy resin contains both multiple epoxide moieties and a diamine held latent by thermally degradable carbamate linkages. These bis-carbamate "single molecule epoxies" have an essentially infinite shelf life and access a significant range in curing temperatures related to the structure of the carbamate linkages used. © 2011 American Chemical Society.

  6. Stars resembling the Sun

    Science.gov (United States)

    Cayrel de Strobel, G.

    This review is primarily directed to the question whether photometric solar analogues remain such when subjected to detailed spectroscopic analyses and interpreted with the help of internal stucture models. In other words, whether the physical parameters: mass, chemical composition, age (determining effective temperature and luminosity), chromospheric activity, equatorial rotation, lithium abundance, velocity fields etc., we derive from the spectral analysis of a photometric solar analogue, are really close to those of the Sun. We start from 109 photometric solar analogues extracted from different authors. The stars selected had to satisfy three conditions: i) their colour index (B-V) must be contained in the interval: Δ (B-V) = 0.59-0.69, ii) they must possess a trigonometric parallax, iii) they must have undergone a high resolution detailed spectroscopic analysis. First, this review presents photometric and spectrophotometric researches on solar analogues and recalls the pionneering work on these stars by the late Johannes Hardorp. After a brief discussion on low and high resolution spectroscopic researches, a comparison is made between effective temperatures as obtained, directly, from detailed spectral analyses and those obtained, indirectly, from different photometric relations. An interesting point in this review is the discussion on the tantalilizing value of the (B-V)solar of the Sun, and the presentation of a new reliable value of this index. A short restatement of the kinematic properties of the sample of solar analogues is also made. And, finally, the observational ( T eff, M bol) diagram, obtained with 99 of the initially presented 109 analogues, is compared to a theoretical ( T eff, M bol) diagram. This latter has been constructed with a grid of internal structure models for which, (very important for this investigation), the Sun was used as gauge. In analysing the position, with respect to the Sun, of each star we hoped to find a certain number of

  7. A new perspective on quiet Sun magnetism

    Institute of Scientific and Technical Information of China (English)

    LITES; Bruce; William

    2009-01-01

    The Hinode mission has provided us with a new, quantitative view of the magnetism of the quiet Sun. It has revealed that the quiet internetwork areas are blanketed by horizontal fields that appear at first sight to have more flux than the vertical fields resolved on the same 0.3 size scale. These measurements point to the possibility that the horizontal fields might be the primary source of the "hidden turbulent flux" of the quiet Sun anticipated from Hanle effect depolarization. In this paper, evidence is presented suggesting that the "seething" horizontal fields observed by Harvey in 2007 and the horizontal fields revealed by Hinode are the same phenomenon. Because the seething fields appear to be of uniform fluctuation over the whole disk, the phenomenon is most likely not associated with the dynamo source of solar activity. Thus, the small-scale "hidden turbulent flux" lends support to the notion of a local solar dynamo acting on granular sizes and time scales.

  8. Curing of epoxy matrix composite in stratosphere

    Science.gov (United States)

    Kondyurin, Alexey; Kondyurina, Irina; Bilek, Marcela

    Large structures for habitats, greenhouses, space bases, space factories are needed for next stage of space exploitation. A new approach enabling large-size constructions in space relies on the use of the polymerization technology of fiber-filled composites with a curable polymer matrix applied in the free space environment. The polymerisation process is proposed for the material exposed to high vacuum, dramatic temperature changes, space plasma, sun irradiation and atomic oxygen (in low Earth orbit), micrometeorite fluence, electric charging and microgravitation. The stratospheric flight experiments are directed to an investigation of the curing polymer matrix under the stratospheric conditions on. The unique combination of low atmospheric pressure, high intensity UV radiation including short wavelength UV and diurnal temperature variations associated with solar irradiation strongly influences the chemical processes in polymeric materials. The first flight experiment with uncured composites was a part of the NASA scientific balloon flight program realised at the NASA stratospheric balloon station in Alice Springs, Australia. A flight cassette installed on payload was lifted with a “zero-pressure” stratospheric balloon filled with Helium. Columbia Scientific Balloon Facility (CSBF) provided the launch, flight telemetry and landing of the balloon and payload. A cassette of uncured composite materials with an epoxy resin matrix was exposed 3 days in the stratosphere (40 km altitude). The second flight experiment was realised in South Australia in 2012, when the cassette was exposed in 27 km altitude. An analysis of the chemical structure of the composites showed, that the space irradiations are responsible for crosslinking of the uncured polymers exposed in the stratosphere. The first prepreg in the world was cured successfully in stratosphere. The investigations were supported by Alexander von Humboldt Foundation, NASA and RFBR (12-08-00970) grants.

  9. Solar flare leaves sun quaking

    Science.gov (United States)

    1998-05-01

    energy, and produce X-rays, microwaves and a shock wave that heats the solar surface. Kosovichev and Zharkova developed a theory that predicts the nature and magnitude of the shock waves that this beam of energetic electrons should create when they slam down into the solar atmosphere. Although their theory directed them to the right area to search for the seismic waves, the waves that they found were 10 times stronger than they had predicted. "They were so strong that you can see them in the raw data," Kosovichev says. The solar seismic waves appear to be compression waves like the "P" waves generated by an earthquake. They travel throughout the Sun's interior. In fact, the waves should recombine on the opposite side of the Sun from the location of the flare to create a faint duplicate of the original ripple pattern, Kosovichev predicts. Now that they know how to find them, the SOHO scientists say that the seismic waves generated by solar flares should allow them to verify independently some of the conditions in the solar interior that they have inferred from studying the pattern of waves that are continually ruffling the Sun's surface. SOHO is part of the International Solar-Terrestrial Physics (ISTP) program, a global effort to observe and understand our star and its effects on our environment. The ISTP mission includes more than 20 satellites, coupled with with ground-based observatories and modeling centers, that allow scientists to study the Sun, the Earth, and the space between them in unprecedented detail. ISTP is a joint program of NASA, ESA, Japan's Institute for Astronautical Science, and Russia's Space Research Institute. Still images of the solar quake can be found at the following internet address: FTP://PAO.GSFC.NASA.GOV/newsmedia/QUAKE/ For further information, please contact : ESA Public Relations Division Tel:+33(0)1.53.69.71.55 Fax: +33(0)1.53.69.76.90 3

  10. SCIENCE OF SUN PHOTOMETRY

    Directory of Open Access Journals (Sweden)

    Alexandru Dan Toma

    2013-07-01

    Full Text Available Typically, the total amount of gases and particles in a column of atmosphere cannot be determined from measurements just at Earth's surface, by a single measurement essentially at the bottom of the atmosphere column. Balloons, airplanes, and rockets are all used to perform direct measurements in the atmosphere at altitudes up to and beyond the stratosphere. Satellite-based instruments provide global views, but it is difficult to infer surface and column distributions from space-based measurements, so such measurements must still be supplemented by ground-based measurements. Sun photometry is an important way of probing the atmosphere from the ground to measure the effects of the atmosphere on Sun radiation crossing through the atmosphere to Earth's surface. These indirect technique provide information about the entire atmosphere above the observer, not just the atmosphere that can be sampled directly close to Earth's surface.

  11. How hot is the sun

    Institute of Scientific and Technical Information of China (English)

    刘超

    2001-01-01

    Do you know how hot thesun is? There are no solidsor liquids on the sun. Why not? The temperature onoutside the sun is more than 10, 000℃, and that at the centre is about 20, 000, 000℃.The sun is so hot that all thesolids and all the liquids havebeen turned into gases.

  12. The sun, our star

    Science.gov (United States)

    Noyes, R. W.

    Observational data, analytical models, and instrumentation used to study the sun and its evolution are detailed, and attention is given to techniques for converting solar energy to useful power on earth. The star ignited when the mutual gravitational attractions of dust and vapor in a primordial cloud in the Galaxy caused an in-rush of accelerating particles which eventually became dense enough to ignite. The heat grew until inward rushing matter was balanced by outward moving radiative forces. The planets formed from similar debris, and solar radiation is suggested to have triggered the chemical reactions giving rise to life on earth. Visual, spectroscopic, coronagraphic, and UV observations of the sun from the ground and from spacecraft, particularly Skylab, are described, together with features of the solar surface, magnetic field, sunspots, and coronal loops. Models for the processes that occur in the solar interior are explored, as are the causes of solar flares. Attention is given to solar cells, heliostat arrays, wind turbines, and water turbines as means to convert, either directly or indirectly, the earth-bound solar energy to electrical and thermal power. Finally, the life cycle of the sun, about 9 billion yr in duration, is summarized, noting the current status of midlife.

  13. Galileo Mission Science Briefing

    Science.gov (United States)

    1989-07-01

    The first of two tapes of the Galileo Mission Science press briefing is presented. The panel is moderated by George Diller from the Kennedy Space Center (KSC) Public Affairs Office. The participants are John Conway, the director of Payload and operations at Kennedy; Donald E. Williams, Commander of STS-43, the shuttle mission which will launch the Galileo mission; John Casani, the Deputy Assistant Director of Flight Projects at the Jet Propulsion Lab (JPL); Dick Spehalski, Galileo Project Manager at JPL; and Terrence Johnson, Galileo Project Scientist at JPL. The briefing begins with an announcement of the arrival of the Galileo Orbiter at KSC. The required steps prior to the launch are discussed. The mission trajectory and gravity assists from planetary and solar flybys are reviewed. Detailed designs of the orbiter are shown. The distance that Galileo will travel from the sun precludes the use of solar energy for heat. Therefore Radioisotope heater units are used to keep the equipment at operational temperature. A video of the arrival of the spacecraft at KSC and final tests and preparations is shown. Some of the many science goals of the mission are reviewed. Another video showing an overview of the Galileo mission is presented. During the question and answer period, the issue of the use of plutonium on the mission is broached, which engenders a review of the testing methods used to ensure the safety of the capsules containing the hazardous substance. This video has actual shots of the orbiter, as it is undergoing the final preparations and tests for the mission.

  14. Thermoset epoxy polymers from renewable resources

    Science.gov (United States)

    East, Anthony; Jaffe, Michael; Zhang, Yi; Catalani, Luiz H

    2009-11-17

    Novel thermoset epoxy polymers using the bisglycidyl ethers of anhydrosugars, such as isosorbide, isomannide, and isoidide, are disclosed. The bisglycidyl ethers are useful as substitutes for bisphenol A in the manufacture of thermoset epoxy ethers. The anhydrosugars are derived from renewable sources and the bisglycidyl ethers are not xenoestrogenic and the thermoset curing agents are likewise derived form renewable resources.

  15. [Delayed asthma bronchiale due to epoxy resin].

    Science.gov (United States)

    Authried, Georg; Al-Asadi, Haifaa; Møller, Ulla; Sherson, David Lee

    2013-10-28

    Epoxy resin is a low molecular weight agent, which can cause both acute and delayed allergic reactions. However, it is known causing skin reactions with direct or airborne contact. Rarely it can cause airway reactions like asthma bronchiale. We describe a case of a windmill worker who developed delayed asthma bronchiale due to airborne contact with epoxy resin.

  16. Astmatisk senreaktion efter kontakt med epoxy

    DEFF Research Database (Denmark)

    Authried, Georg; Al-Asadi, Haifaa; Møller, Ulla;

    2013-01-01

    Epoxy resin is a low molecular weight agent, which can cause both acute and delayed allergic reactions. However, it is known causing skin reactions with direct or airborne contact. Rarely it can cause airway reactions like asthma bronchiale. We describe a case of a windmill worker who developed...... delayed asthma bronchiale due to airborne contact with epoxy resin....

  17. Astmatisk senreaktion efter kontakt med epoxy

    DEFF Research Database (Denmark)

    Authried, Georg; Al-Asadi, Haifaa; Møller, Ulla

    2013-01-01

    Epoxy resin is a low molecular weight agent, which can cause both acute and delayed allergic reactions. However, it is known causing skin reactions with direct or airborne contact. Rarely it can cause airway reactions like asthma bronchiale. We describe a case of a windmill worker who developed...... delayed asthma bronchiale due to airborne contact with epoxy resin....

  18. Comparative properties of optically clear epoxy encapsulants

    Science.gov (United States)

    Edwards, Maury; Zhou, Yan

    2001-12-01

    Three epoxy systems were evaluated for physical dn optical properties. The three systems chosen for the study were selected on the basis of their optical clarity, color and chemistry. Three distinctly different chemistries were chosen, aromatic epoxy-amine cured. Aromatic epoxy- anhydride cured and cycloaliphatic epoxy-anhydride cured. All three systems remained optically clear and water-white after full cure. The three selected systems were tested for physical properties, adhesion and light transmission properties. Light transmission was measured after thermal and humidity exposure. Adhesion was measured after humidity exposure only. Both of the epoxy-anhydride systems performed well in optical properties but poorer in adhesion as compared to the epoxy-amine system. The aromatic epoxy- amine system discolored badly during thermal exposure at 100 C. Data generated from this work will be used in selecting clear encapsulating materials for photonics applications. No single system offers optimal performance in all areas. The best compromise material is the aromatic epoxy-anhydride system.

  19. KuaFu Mission

    Institute of Scientific and Technical Information of China (English)

    XIA Lidong; TU Chuanyi; Schwenn Rainer; Donovan Eric; Marsch Eckart; WANG Jingsong; ZHANG Yongwei; XIAO Zuo

    2006-01-01

    The KuaFu mission-Space Storms, Aurora and Space Weather Explorer-is an "L1+Polar" triple satellite project composed of three spacecraft: KuaFu-A will be located at L1 and have instruments to observe solar EUV and FUV emissions, and white-light Coronal Mass Ejections (CMEs), and to measure radio waves, the local plasma and magnetic field,and high-energy particles. KuaFuB1 and KuaFu- B2 will bein polar orbits chosen to facilitate continuous 24 hours a day observation of the north polar Aurora Oval. The KuaFu mission is designed to observe the complete chain of disturbances from the solar atmosphere to geospace, including solar flares, CMEs, interplanetary clouds, shock waves, and their geo-effects, such as magnetospheric sub-storms and magnetic storms, and auroral activities. The mission may start at the next solar maximum (launch in about 2012), and with an initial mission lifetime of two to three years. KuaFu data will be used for the scientific study of space weather phenomena, and will be used for space weather monitoring and forecast purposes. The overall mission design, instrument complement, and incorporation of recent technologies will target new fundamental science, advance our understanding of the physical processes underlying space weather, and raise the standard of end-to-end monitoring of the Sun-Earth system.

  20. Gas mission; Mission gaz

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-07-01

    This preliminary report analyses the desirable evolutions of gas transport tariffing and examines some questions relative to the opening of competition on the French gas market. The report is made of two documents: a synthesis of the previous report with some recommendations about the tariffing of gas transport, about the modalities of network access to third parties, and about the dissociation between transport and trade book-keeping activities. The second document is the progress report about the opening of the French gas market. The first part presents the European problem of competition in the gas supply and its consequences on the opening and operation of the French gas market. The second part presents some partial syntheses about each topic of the mission letter of the Ministry of Economics, Finances and Industry: future evolution of network access tariffs, critical analysis of contractual documents for gas transport and delivery, examination of auxiliary services linked with the access to the network (modulation, balancing, conversion), consideration about the processing of network congestions and denied accesses, analysis of the metering dissociation between the integrated activities of gas operators. Some documents are attached in appendixes: the mission letter from July 9, 2001, the detailed analysis of the new temporary tariffs of GdF and CFM, the offer of methane terminals access to third parties, the compatibility of a nodal tariffing with the presence of three transport operators (GdF, CFM and GSO), the contract-type for GdF supply, and the contract-type for GdF connection. (J.S.)

  1. Curing Reaction Model of Epoxy Asphalt Binder

    Institute of Scientific and Technical Information of China (English)

    QIAN Zhendong; CHEN Leilei; WANG Yaqi; SHEN Jialin

    2012-01-01

    In order to understand the strength developing law of the epoxy asphalt mixture,a curing reaction model of the epoxy asphalt binder was proposed based upon the thermokinetic analysis.Given some assumptions,the model was developed by applying the Kissinger law as well as Arrhenius equation,and the differential scanning calorimetry was performed for estimating the model parameters.To monitor the strength development of the epoxy asphalt mixture,a strength test program was employed and then results were compared to those produced from the proposed model.The comparative evaluation shows that a good consistency exists between the outputs from test program and the proposed model,indicating that the proposed model can be used effectively for simulating the curing reaction process for the epoxy asphalt binder and predicting the strength development for the epoxy asphalt mixture.

  2. Waterborne Epoxy Resin Modified by AMPS

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A stable epoxy emulsion was prepared with epoxy resin (EP) as raw material, 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS) as modifier and benzoyl peroxide as initiator. By criterion of yield of the copolymer AMPS-EP, water-solubility, change of the acid value and intrinsic viscosity [η] along with reaction time, the copolymerization course was deduced. It is found that during the process, AMPS takes part in both the grafting copolymerization with epoxy principal chain and the ring-opening polyaddition with epoxy group. It is also discovered that the yield of AMPS-EP and water dispersing varies with reaction time. When it reaches 1.5 h,AMPS-EP can obtain good water-solubility; but the water-solubility will go bad gradually ifit exceeds 3.5 h.( )R spectrum analysis indicates that partial epoxy group partially remains and the others create sulfonic ester.

  3. The ARTEMIS mission

    CERN Document Server

    Angelopoulos, Vassilis

    2014-01-01

    The ARTEMIS mission was initiated by skillfully moving the two outermost Earth-orbiting THEMIS spacecraft into lunar orbit to conduct unprecedented dual spacecraft observations of the lunar environment. ARTEMIS stands for Acceleration, Reconnection, Turbulence and Electrodynamics of the Moon's Interaction with the Sun. Indeed, this volume discusses initial findings related to the Moon’s magnetic and plasma environments and the electrical conductivity of the lunar interior. This work is aimed at researchers and graduate students in both heliophysics and planetary physics. Originally published in Space Science Reviews, Vol. 165/1-4, 2011.

  4. A method for lunar roving vehicle position determination from three landmark observations with a sun compass

    Science.gov (United States)

    Blucker, T. J.; Stimmel, G. L.

    1971-01-01

    A simplified method is described for determining the position of the lunar roving vehicle on the lunar surface during Apollo 15. The method is based upon sun compass azimuth measurements of three lunar landmarks. The difference between the landmark azimuth and the sun azimuth is measured and the resulting data are voice relayed to the Mission Control Center for processing.

  5. Imide modified epoxy matrix resins

    Science.gov (United States)

    Scola, D. A.

    1984-01-01

    The results of a program designed to develop tough imide modified epoxy resins cured by bisimide amine (BIA) hardeners are described. State-of-the-art epoxides MY720 and DER383 were used, and four bismide amines were evaluated. These were the BIA's derived from the 6F anhydride (4,4'-(hexafluoroisopropylidene) bis(phthalic anhydride) and the diamines 3,3'-diaminodiphynyl sulfone, 4,4'-oxygianiline, 4,4'-methylene dianiline, and 1,12-dodecane diamine. A key intermediate, designated 6F anhydride, is required for the synthesis of the bisimide amines. Reaction parameters to synthesize a precursor to the 6F anhydride (6FHC) in high yields were investigated. The catalyst trifluoromethane sulfonic acid was studied. Although small scale runs yielded the 6FHC in 50 percent yield, efforts to ranslate these results to a larger scale synthesis gave the 6FHC in only 9 percent yield. Results show that the concept of using bisimide amine as curing agents to improve the toughness properties of epoxies is valid.

  6. The Euclid mission design

    CERN Document Server

    Racca, Giuseppe D; Stagnaro, Luca; Salvignol, Jean Christophe; Alvarez, Jose Lorenzo; Criado, Gonzalo Saavedra; Venancio, Luis Gaspar; Short, Alex; Strada, Paolo; Boenke, Tobias; Colombo, Cyril; Calvi, Adriano; Maiorano, Elena; Piersanti, Osvaldo; Prezelus, Sylvain; Rosato, Pierluigi; Pinel, Jacques; Rozemeijer, Hans; Lesna, Valentina; Musi, Paolo; Sias, Marco; Anselmi, Alberto; Cazaubiel, Vincent; Vaillon, Ludovic; Mellier, Yannick; Amiaux, Jerome; Berthe, Michel; Sauvage, Marc; Azzollini, Ruyman; Cropper, Mark; Pottinger, Sabrina; Jahnke, Knud; Ealet, Anne; Maciaszek, Thierry; Pasian, Fabio; Zacchei, Andrea; Scaramella, Roberto; Hoar, John; Kohley, Ralf; Vavrek, Roland; Rudolph, Andreas; Schmidt, Micha

    2016-01-01

    Euclid is a space-based optical/near-infrared survey mission of the European Space Agency (ESA) to investigate the nature of dark energy, dark matter and gravity by observing the geometry of the Universe and on the formation of structures over cosmological timescales. Euclid will use two probes of the signature of dark matter and energy: Weak gravitational Lensing, which requires the measurement of the shape and photometric redshifts of distant galaxies, and Galaxy Clustering, based on the measurement of the 3-dimensional distribution of galaxies through their spectroscopic redshifts. The mission is scheduled for launch in 2020 and is designed for 6 years of nominal survey operations. The Euclid Spacecraft is composed of a Service Module and a Payload Module. The Service Module comprises all the conventional spacecraft subsystems, the instruments warm electronics units, the sun shield and the solar arrays. In particular the Service Module provides the extremely challenging pointing accuracy required by the sc...

  7. Mechanical and Thermoviscoelastic Behavior of Clay/Epoxy Nanocomposites

    Science.gov (United States)

    2003-01-01

    bisphenol A ( DGEBA ) epoxy of subambient glass transition temperature (Tg) with 5% weight of montmorillonite. The authors showed that no big improvements...reinforced polymers for structural applications. The epoxy system considered here is an anhydride-cured epoxy consisting of a DGEBA epoxy resin cross-linked

  8. Review - The Sun Rises

    Directory of Open Access Journals (Sweden)

    Mark Bender

    2012-12-01

    Full Text Available Review of: Blackburn, Stuart H. 2010. The Sun Rises: A Shaman's Chant, Ritual Exchange and Fertility in the Apatani Valley. Leiden: Brill. xvii+401. Color and black and white photographs, maps. ISBN: 9789-0041-7578-5 (hardcover, 97USD. The Sun Rises is a model study contextualizing an oral narrative tradition in the social and ritual fabric of a remote community in northeast India. In many ways a companion volume to Himalayan Tribal Tales (Blackburn 2008, the text presents the first substantial translation of a key ritual text of the Apantani Valley dwellers in Arunachal Pradesh, located on the contested border between China (Tibet and India. The Apatani speak a Tibeto-Burman language, practice intensive rice agriculture in carefully terraced fields, and number about 35,000. Their clans populate several centuries-old villages. Until recently, they were separated from the lowlands of Assam and surrounded only by peoples practicing various forms of shifting agriculture. The valley dwellers have increasingly encountered modernization over the last few decades, including Indian and global popular culture, and Christianity. The heart of this book is a chant of nineteen segments.

  9. Keeping Cool Close to the Sun

    Energy Technology Data Exchange (ETDEWEB)

    Hazi, A

    2006-01-13

    The germanium detector in the gamma-ray spectrometer (GRS) aboard the MESSENGER spacecraft is only the size and weight of a can of peaches but will play a critical role in investigating Mercury, the planet closest to the Sun. The MESSENGER (MErcury Surface, Space ENvironment, GEochemistry, and Ranging) spacecraft travels at about 38 kilometers per second and is named after the scientific goals of the mission. It is the first spacecraft to visit Mercury since 1975. MESSENGER must take an oblique route to approach Mercury so that it does not fly past the planet and fall directly into the Sun. The spacecraft will travel 7.9 billion kilometers, flying by Earth once, Venus twice, and Mercury three times before settling into orbit around this mysterious planet. Of all the terrestrial planets, which include Venus, Earth, and Mars, Mercury is the smallest and the densest; its days are 176 Earth days long, two complete orbits of the planet around the Sun. Temperatures range from a high of 450 C on the Sun side during its long day to a low of -185 C on its night side. By studying this extreme planet, scientists hope to better understand how Earth formed and evolved. The GRS, one of the seven lightweight scientific instruments on MESSENGER, will be used to help scientists determine the abundance of elements in Mercury's crust, including the materials that might be ice at its poles. Livermore engineer Norman Madden led the West Coast team effort to design and build the GRS in a collaboration led by Johns Hopkins University Applied Physics Laboratory (JHUAPL). The team included Lawrence Berkeley and Lawrence Livermore national laboratories as well as University of California at Berkeley (UCB) Space Sciences Laboratory (SSL). The JHUAPL MESSENGER project is a National Aeronautics and Space Administration (NASA) Discovery Mission. Because the detector needs to operate at very low temperatures and MESSENGER is close to the Sun, the thermal design to protect the detector was

  10. Eruptions from the Sun

    Science.gov (United States)

    Kohler, Susanna

    2015-11-01

    The Sun often exhibits outbursts, launching material from its surface in powerful releases of energy. Recent analysis of such an outburst captured on video by several Sun-monitoring spacecraft may help us understand the mechanisms that launch these eruptions.Many OutburstsSolar jets are elongated, transient structures that are thought to regularly release magnetic energy from the Sun, contributing to coronal heating and solar wind acceleration. Coronal mass ejections (CMEs), on the other hand, are enormous blob-like explosions, violently ejecting energy and mass from the Sun at incredible speeds.But could these two types of events actually be related? According to a team of scientists at the University of Science and Technology of China, they may well be. The team, led by Jiajia Liu, has analyzed observations of a coronal jet that they believe prompted the launch of a powerful CME.Observing an ExplosionGif of a movie of the CME, taken by the Solar Dynamics Observatorys Atmospheric Imaging Assembly at a wavelength of 304. The original movie can be found in the article. [Liu et al.]An army of spacecraft was on hand to witness the event on 15 Jan 2013 including the Solar Dynamics Observatory (SDO), the Solar and Heliospheric Observatory (SOHO), and the Solar Terrestrial Relations Observatory (STEREO). The instruments on board these observatories captured the drama on the northern limb of the Sun as, at 19:32 UT, a coronal jet formed. Just eight minutes later, a powerful CME was released from the same active region.The fact that the jet and CME occurred in the same place at roughly the same time suggests theyre related. But did the initial motions of the CME blob trigger the jet? Or did the jet trigger the CME?Tying It All TogetherIn a recently published study, Liu and collaborators analyzed the multi-wavelength observations of this event to find the heights and positions of the jet and CME. From this analysis, they determined that the coronal jet triggered the release

  11. Recognition of epoxy with phage displayed peptides.

    Science.gov (United States)

    Swaminathan, Swathi; Cui, Yue

    2013-07-01

    The development of a general approach for non-destructive chemical and biological functionalization of epoxy could expand opportunities for both fundamental studies and creating various device platforms. Epoxy shows unique electrical, mechanical, chemical and biological compatibility and has been widely used for fabricating a variety of devices. Phage display has emerged as a powerful method for selecting peptides that possess enhanced selectivity and binding affinity toward a variety of targets. In this letter, we demonstrate for the first time a powerful yet benign approach for identifying binding motifs to epoxy via comprehensively screened phage displayed peptides. Our results show that the epoxy can be selectively recognized with peptide-displaying phages. Further, along with the development of epoxy-based microstructures; recognition of the epoxy with phage displayed peptides can be specifically localized in these microstructures. We anticipate that these results could open up exciting opportunities in the use of peptide-recognized epoxy in fundamental biochemical recognition studies, as well as in applications ranging from analytical devices, hybrid materials, surface and interface, to cell biology. Copyright © 2013 Elsevier B.V. All rights reserved.

  12. Mechanical behaviors of hyberbranched epoxy toughened bisphenol F epoxy resin for cryogenic applications

    Science.gov (United States)

    Li, Jingwen; Wu, Zhixiong; Huang, Chuanjun; Huang, Rongjin; Li, Laifeng

    2014-01-01

    Epoxy resins have been widely employed in cryogenic engineering fields. In this work, bisphenol F epoxy resin was modified by an aromatic polyester hyperbranched epoxy resin (HTDE-2). Mechanical behaviors of the modified epoxy resins in terms of tensile properties and impact property were studied at both room and cryogenic temperatures. Moreover, the toughening mechanism was discussed by fracture surface morphology analysis. The results demonstrated that, the mechanical properties of composites initially increased until reaches the maximum value with increasing the mass content of the HTDE-2, and then decreased at both room temperature (RT) and 77K. Especially, the impact strength at 77 K was improved 40.7% compared with the pure epoxy matrix when 10 wt% HTDE-2 was introduced. The findings suggest that the HTDE-2 will be an effective toughener for the brittle bisphenol F epoxy resin for cryogenic applications.

  13. Synthesis and characterization of novel multifunctional epoxy resin

    Institute of Scientific and Technical Information of China (English)

    Jue Cheng; Jing Chen; Wan Tai Yang

    2007-01-01

    A novel multifunctional epoxy resin was synthesized by polyphenol and epichlorohydrin. The structure and molecular weight of the multifunctional epoxy were characterized by FTIR and ESI-MS. DSC and DMTA were used to investigate the thermal property of multifunctional epoxy cured by DDS. The thermal resistance of the synthesized multifunctional epoxy was much better than a standard diglycidyl ether of bisphenol-A epoxy.

  14. Advanced resin systems for graphite epoxy composites

    Science.gov (United States)

    Gilwee, W. J.; Jayarajan, A.

    1980-01-01

    The value of resin/carbon fiber composites as lightweight structures for aircraft and other vehicle applications is dependent on many properties: environmental stability, strength, toughness, resistance to burning, smoke produced when burning, raw material costs, and complexity of processing. A number of woven carbon fiber and epoxy resin composites were made. The epoxy resin was commercially available tetraglycidylmethylene dianiline. In addition, composites were made using epoxy resin modified with amine and carboxyl terminated butadiene acrylonitrile copolymer. Strength and toughness in flexure as well as oxygen index flammability and NBS smoke chamber tests of the composites are reported.

  15. Epoxy Foam Encapsulants: Processing and Dielectric Characterization

    Energy Technology Data Exchange (ETDEWEB)

    Linda Domeier; Marion Hunter

    1999-01-01

    The dielectric performance of epoxy foams was investigated to determine if such materials might provide advantages over more standard polyurethane foams in the encapsulation of electronic assemblies. Comparisons of the dielectric characteristics of epoxy and urethane encapsulant foams found no significant differences between the two resin types and no significant difference between as-molded and machined foams. This study specifically evaluated the formulation and processing of epoxy foams using simple methylhydrosiloxanes as the flowing agent and compared the dielectric performance of those to urethane foams of similar density.

  16. The validated sun exposure questionnaire

    DEFF Research Database (Denmark)

    Køster, B; Søndergaard, J; Nielsen, J B

    2017-01-01

    Few questionnaires used in monitoring sun-related behavior have been tested for validity. We established criteria validity of a developed questionnaire for monitoring population sun-related behavior. During May-August 2013, 664 Danes wore a personal electronic UV-dosimeter for one week...... that measured the outdoor time and dose of erythemal UVR exposure. In the following week, they answered a questionnaire on their sun-related behavior in the measurement week. Outdoor time measured by dosimetry correlated strongly with both outdoor time and the developed exposure scale measured....... The weekly sunburn fraction correlated strongly with the number of ambient sun hours (r=0.73, p

  17. The Sun's dusty interstellar environment

    Science.gov (United States)

    Sterken, Veerle

    2016-07-01

    The Sun's dusty interstellar environment Interstellar dust from our immediate interstellar neighborhood travels through the solar system at speeds of ca. 26 km/s: the relative speed of the solar system with respect to the local interstellar cloud. On its way, its trajectories are altered by several forces like the solar radiation pressure force and Lorentz force. The latter is due to the charged dust particles that fly through the interplanetary magnetic field. These trajectories differ per particle type and size and lead to varying fluxes and directions of the flow inside of the solar system that depend on location but also on phase in the solar cycle. Hence, these fluxes and directions depend strongly on the configuration of the inner regions and outer regions of the heliosphere. Several missions have measured this dust in the solar system directly. The Ulysses dust detector data encompasses 16 years of intestellar dust fluxes and approximate directions, Stardust captured returned to Earth a few of these particles sucessfully, and finally the Cassini dust detector allowed for compositional information to be obtained from the impacts on the instrument. In this talk, we give an overview of the current status of interstellar dust research through the measurements made inside of the solar system, and we put them in perspective to the knowledge obtained from more classical astronomical means. In special, we focus on the interaction of the dust with the interplanetary magnetic field, and on what we learn about the dust (and the fields) by comparing the available dust data to computer simulations of dust trajectories. Finally, we synthesize the different methods of observation, their results, and give a preview on new research opportunities in the coming year(s).

  18. Autonomous Sun-Direction Estimation Using Partially Underdetermined Coarse Sun Sensor Configurations

    Science.gov (United States)

    O'Keefe, Stephen A.

    In recent years there has been a significant increase in interest in smaller satellites as lower cost alternatives to traditional satellites, particularly with the rise in popularity of the CubeSat. Due to stringent mass, size, and often budget constraints, these small satellites rely on making the most of inexpensive hardware components and sensors, such as coarse sun sensors (CSS) and magnetometers. More expensive high-accuracy sun sensors often combine multiple measurements, and use specialized electronics, to deterministically solve for the direction of the Sun. Alternatively, cosine-type CSS output a voltage relative to the input light and are attractive due to their very low cost, simplicity to manufacture, small size, and minimal power consumption. This research investigates using coarse sun sensors for performing robust attitude estimation in order to point a spacecraft at the Sun after deployment from a launch vehicle, or following a system fault. As an alternative to using a large number of sensors, this thesis explores sun-direction estimation techniques with low computational costs that function well with underdetermined sets of CSS. Single-point estimators are coupled with simultaneous nonlinear control to achieve sun-pointing within a small percentage of a single orbit despite the partially underdetermined nature of the sensor suite. Leveraging an extensive analysis of the sensor models involved, sequential filtering techniques are shown to be capable of estimating the sun-direction to within a few degrees, with no a priori attitude information and using only CSS, despite the significant noise and biases present in the system. Detailed numerical simulations are used to compare and contrast the performance of the five different estimation techniques, with and without rate gyro measurements, their sensitivity to rate gyro accuracy, and their computation time. One of the key concerns with reducing the number of CSS is sensor degradation and failure. In

  19. The Rapidly Rotating Sun

    Science.gov (United States)

    Hanasoge, Shravan M.; Duvall, Thomas L., Jr.; Sreenivasan, Katepalli R.

    2012-01-01

    Convection in the solar interior is thought to comprise structures at a continuum of scales, from large to small. This conclusion emerges from phenomenological studies and numerical simulations though neither covers the proper range of dynamical parameters of solar convection. In the present work, imaging techniques of time-distance helioseismology applied to observational data reveal no long-range order in the convective motion. We conservatively bound the associated velocity magnitudes, as a function of depth and the spherical-harmonic degree l to be 20-100 times weaker than prevailing estimates within the wavenumber band l ux of a solar luminosity outwards? The Sun is seemingly a much faster rotator than previously thought, with advection dominated by Coriolis forces at scales l < 60.

  20. Sun light European Project

    Science.gov (United States)

    Soubielle, Marie-Laure

    2015-04-01

    2015 has been declared the year of light. Sunlight plays a major role in the world. From the sunbeams that heat our planet and feed our plants to the optical analysis of the sun or the modern use of sun particles in technologies, sunlight is everywhere and it is vital. This project aims to understand better the light of the Sun in a variety of fields. The experiments are carried out by students aged 15 to 20 in order to share their discoveries with Italian students from primary and secondary schools. The experiments will also be presented to a group of Danish students visiting our school in January. All experiments are carried out in English and involve teams of teachers. This project is 3 folds: part 1: Biological project = what are the mechanisms of photosynthesis? part 2: Optical project= what are the components of sunlight and how to use it? part 3: Technical project= how to use the energy of sunlight for modern devices? Photosynthesis project Biology and English Context:Photosynthesis is a process used by plants and other organisms to convert light energy, normally from the Sun, into chemical energy that can later fuel the organisms' activities. This chemical energy is stored in molecules which are synthesized from carbon dioxide and water. In most cases, oxygen is released as a waste product. Most plants perform photosynthesis. Photosynthesis maintains atmospheric oxygen levels and supplies all of the organic compounds and most of the energy necessary for life on Earth. Outcome: Our project consists in understanding the various steps of photosynthesis. Students will shoot a DVD of the experiments presenting the equipments required, the steps of the experiments and the results they have obtained for a better understanding of photosynthesis Digital pen project Electricity, Optics and English Context: Sunlight is a complex source of light based on white light that can be decomposed to explain light radiations or colours. This light is a precious source to create

  1. Physics of the sun

    CERN Document Server

    Holzer, Thomas; Mihalas, Dimitri; Ulrich, Roger

    1986-01-01

    This volume, together with its two companion volumes, originated in a study commis­ sioned by the United States National Academy of Sciences on behalf of the National Aeronautics and Space Administration. A committee composed of Tom Holzer, Dimitri Mihalas, Roger Ulrich and myself was asked to prepare a comprehensive review of current knowledge concerning the physics of the sun. We were fortunate in being able to persuade many distinguished scientists to gather their forces for the preparation of 21 separate chapters covering not only solar physics but also relevant areas of astrophysics and solar-terrestrial relations. It proved necessary to divide the chapters into three separate volumes that cover three different aspects of solar physics. Volumes 1 and 2 are concerned with 'The Solar Interior' and with 'The Solar Atmosphere'. This volume, devoted to 'Astrophysics and Solar-Terrestrial Relations', focuses on problems of solar physics from these two different but complementary perspectives. The emphasis thr...

  2. Structural/Radiation-Shielding Epoxies

    Science.gov (United States)

    Connell, John W.; Smith, Joseph G.; Hinkley, Jeffrey; Blattnig, Steve; Delozier, Donavon M.; Watson, Kent A.; Ghose, Sayata

    2009-01-01

    A development effort was directed toward formulating epoxy resins that are useful both as structural materials and as shielding against heavy-ion radiation. Hydrogen is recognized as the best element for absorbing heavy-ion radiation, and high-hydrogen-content polymers are now in use as shielding materials. However, high-hydrogen-content polymers (e.g. polyethylene) are typically not good structural materials. In contrast, aromatic polymers, which contain smaller amounts of hydrogen, often have the strength necessary for structural materials. Accordingly, the present development effort is based on the concept that an ideal structural/ heavy-ion-radiation-shielding material would be a polymer that contains sufficient hydrogen (e.g., in the form of aliphatic molecular groups) for radiation shielding and has sufficient aromatic content for structural integrity.

  3. Why the sun sucks - Architects versus the sun

    NARCIS (Netherlands)

    De Lange, N.; Niesten, J.; Taminiau, P.

    2014-01-01

    This "designers' manual" is made during the TIDO-course AR0531 Innovation and Sustainability This manual will show how not to design with the Sun. By showing examples how buildings have failed that have not taken the Sun and its effects in consideration, one should get a clearer picture of how you

  4. Why the sun sucks - Architects versus the sun

    NARCIS (Netherlands)

    De Lange, N.; Niesten, J.; Taminiau, P.

    2014-01-01

    This "designers' manual" is made during the TIDO-course AR0531 Innovation and Sustainability This manual will show how not to design with the Sun. By showing examples how buildings have failed that have not taken the Sun and its effects in consideration, one should get a clearer picture of how you

  5. A Community Python Library for Solar Physics (SunPy)

    Science.gov (United States)

    Christe, Steven; Shih, A. Y.; Ireland, J.; Perez-Suarez, D.; Mumford, S.; Hughitt, V. K.; Hewett, R.; Mayer, F.; SunPy Dev Team

    2013-07-01

    Python, a free, cross platform, general purpose, high-level programming language, has seen widespread adoption among the scientific community resulting in the availability of a large range of software, from numerical computation (NumPy, SciPy) and machine learning to spectral analysis and visualization (Matplotlib). SunPy is a data analysis toolkit specializing in providing the software necessary to analyze solar and heliospheric datasets in Python. It aims to provide a free and open-source alternative to the IDL-based SolarSoft (SSW) solar data analysis environment. We present the latest release of SunPy (0.3). This release includes a major refactor of the main SunPy code to improve ease of use for the user as well as a more consistent interface. SunPy provides downloading capability through integration with the Virtual Solar Observatory (VSO) and the the Heliophysics Event Knowledgebase (HEK). It can open image fits files from major solar missions (SDO/AIA, SOHO/EIT, SOHO/LASCO, STEREO) into WCS-aware maps. SunPy provides advanced time-series tools for data from mission such as GOES, SDO/EVE, and Proba2/LYRA as well as support for radio spectra (e.g. e-Callisto). We present examples of solar data analysis in SunPy, and show how Python-based solar data-analysis can leverage the many existing data analysis tools already available in Python. We discuss the future goals of the project and encourage interested users to become involved in the planning and development of SunPy.

  6. Ionic Liquid Epoxy Composite Cryotanks Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The objective of this work is to determine the optimal process for manufacturing lightweight linerless cryogenic storage tanks using ionic liquid epoxy composite...

  7. [Allergic contact eczema from epoxy resin].

    Science.gov (United States)

    Calzado, Leticia; Ortiz-de Frutos, Francisco J; del Prado Sánchez-Caminero, María; Galera, Carmen María; Valverde, Ricardo; Vanaclocha, Francisco

    2005-11-01

    Epoxy resins are plastics that are widely used as electrical insulation, in coatings, and as adhesives and paints. They have strong sensitizing power and are one of the main causes of allergic contact eczema, both in the workplace and elsewhere. We present the case of a worker at a plastics/chemical plant, who handled aeronautical components in the process of manufacturing fuselage parts. He consulted his physician because of eczematous lesions on his fingers, hands and forearms which had developed over a two-year period and were clearly related to his work. The standard battery of skin tests was performed, along with the plastics and adhesives series and tests using the products from his workplace. Positivity was shown to epoxy resins (standard battery) and to the products from his workplace, which included different fiberglass and carbon fiber sheets impregnated with epoxy resins and epoxy adhesives.

  8. Structure Property Relationships of Biobased Epoxy Resins

    Science.gov (United States)

    Maiorana, Anthony Surraht

    The thesis is about the synthesis, characterization, development, and application of epoxy resins derived from sustainable feedstocks such as lingo-cellulose, plant oils, and other non-food feedstocks. The thesis can be divided into two main topics 1) the synthesis and structure property relationship investigation of new biobased epoxy resin families and 2) mixing epoxy resins with reactive diluents, nanoparticles, toughening agents, and understanding co-curing reactions, filler/matrix interactions, and cured epoxy resin thermomechanical, viscoelastic, and dielectric properties. The thesis seeks to bridge the gap between new epoxy resin development, application for composites and advanced materials, processing and manufacturing, and end of life of thermoset polymers. The structures of uncured epoxy resins are characterized through traditional small molecule techniques such as nuclear magnetic resonance, high resolution mass spectrometry, and infrared spectroscopy. The structure of epoxy resin monomers are further understood through the process of curing the resins and cured resins' properties through rheology, chemorheology, dynamic mechanical analysis, tensile testing, fracture toughness, differential scanning calorimetry, scanning electron microscopy, thermogravimetric analysis, and notched izod impact testing. It was found that diphenolate esters are viable alternatives to bisphenol A and that the structure of the ester side chain can have signifi-cant effects on monomer viscosity. The structure of the cured diphenolate based epoxy resins also influence glass transition temperature and dielectric properties. Incorporation of reactive diluents and flexible resins can lower viscosity, extend gel time, and enable processing of high filler content composites and increase fracture toughness. Incorpora-tion of high elastic modulus nanoparticles such as graphene can provide increases in physical properties such as elastic modulus and fracture toughness. The synthesis

  9. Smart, passive sun facing surfaces

    Science.gov (United States)

    Hively, Lee M.

    1996-01-01

    An article adapted for selectively utilizing solar radiation comprises an absorptive surface and a reflective surface, the absorptive surface and the reflective surface oriented to absorb solar radiation when the sun is in a relatively low position, and to reflect solar radiation when the sun is in a relatively high position.

  10. Global Seismology of the Sun

    CERN Document Server

    Basu, Sarbani

    2016-01-01

    The seismic study of the Sun and other stars offers a unique window into the interior of these stars. Thanks to helioseismology, we know the structure of the Sun to admirable precision. In fact, our knowledge is good enough to use the Sun as a laboratory. We have also been able to study the dynamics of the Sun in great detail. Helioseismic data also allow us to probe the changes that take place in the Sun as solar activity waxes and wanes. The seismic study of stars other than the Sun is a fairly new endeavour, but we are making great strides in this field. In this review I discuss some of the techniques used in helioseismic analyses and the results obtained using those techniques. In this review I focus on results obtained with global helioseismology, i.e., the study of the Sun using its normal modes of oscillation. I also briefly touch upon asteroseismology, the seismic study of stars other than the Sun, and discuss how seismic data of others stars are interpreted.

  11. Vacuum impregnation with epoxy of large superconducting magnet structures

    Energy Technology Data Exchange (ETDEWEB)

    Green, M.A.; Coyle, D.E.; Miller, P.B.; Wenzel, W.F.

    1978-06-01

    The Lawrence Berkeley Laboratory (LBL) has been developing a new generation of superconducting magnets which have the helium cooling system as an integral part of the magnet structure. The LBL technique calls for large sections of the magnet structure to be vacuum impregnated with epoxy. The epoxy was chosen for its impregnation properties. Epoxies which have good impregnation characteristics are often subject to cracking when they are cooled to cryogenic temperatures. The cracking of such an epoxy can be controlled by: (1) minimizing the amount of epoxy in the structure; (2) reducing the size of unfilled epoxy spaces; and (3) keeping the epoxy in compression. The technique for using the epoxy is often more important than the formulation of the epoxy. The LBL vacuum impregnation and curing technique is described. Experimental measurements on small samples of coil sections are presented. Practical experience with large vacuum impregnation superconducting coils (up to two meters in dia) is also discussed.

  12. Reconnection on the Sun

    Science.gov (United States)

    Kohler, Susanna

    2016-05-01

    Because the Sun is so close, it makes an excellent laboratory to study processes we cant examinein distant stars. One openquestion is that of how solar magnetic fields rearrange themselves, producing the tremendous releases of energy we observe as solar flares and coronal mass ejections (CMEs).What is Magnetic Reconnection?Magnetic reconnection occurs when a magnetic field rearranges itself to move to a lower-energy state. As field lines of opposite polarity reconnect, magnetic energy is suddenly converted into thermal and kinetic energy.This processis believed to be behind the sudden releases of energy from the solar surface in the form of solar flares and CMEs. But there are many different models for how magnetic reconnection could occur in the magnetic field at the Suns surface, and we arent sure which one of these reconnection types is responsible for the events we see.Recently, however, several studies have been published presenting some of the first observational support of specific reconnection models. Taken together, these observations suggest that there are likely several different types of reconnection happening on the solar surface. Heres a closer look at two of these recent publications:A pre-eruption SDO image of a flaring region (b) looks remarkably similar to a 3D cartoon for typical breakout configuration (a). Click for a closer look! [Adapted from Chen et al. 2016]Study 1:Magnetic BreakoutLed by Yao Chen (Shandong University in China), a team of scientists has presented observations made by the Solar Dynamics Observatory (SDO) of a flare and CME event that appears to have been caused by magnetic breakout.In the magnetic breakout model, a series of loops in the Suns lower corona are confined by a surrounding larger loop structure called an arcade higher in the corona. As the lower loops push upward, reconnection occurs in the upper corona, removing the overlying, confining arcade. Without that extra confinement, the lower coronal loops expand upward

  13. Observing the Sun with NuSTAR

    Science.gov (United States)

    Kohler, Susanna

    2016-07-01

    The Nuclear Spectroscopic Telescope Array (NuSTAR) is a space telescope primarily designed to detect high-energy X-rays from faint, distant astrophysical sources. Recently, however, its occasionally been pointing much closer to home, with the goal of solving a few longstanding mysteries about the Sun.Intensity maps from an observation of a quiet-Sun region near the north solar pole and an active region just below the solar limb. The quiet-Sun data will be searched for small flares that could be heating the solar corona, and the high-altitude emission above the limb may provide clues about particle acceleration. [Adapted from Grefenstette et al. 2016]An Unexpected TargetThough we have a small fleet of space telescopes designed to observe the Sun, theres an important gap: until recently, there was no focusing telescope making solar observations in the hard X-ray band (above ~3 keV). Conveniently, there is a tool capable of doing this: NuSTAR.Though NuSTARs primary mission is to observe faint astrophysical X-ray sources, a team of scientists has recently conducted a series of observations in which NuSTAR was temporarily repurposed and turned to focus on the Sun instead.These observations pose an interesting challenge precisely because of NuSTARs extreme sensitivity: pointing at such a nearby, bright source can quickly swamp the detectors. But though the instrument cant be used to observe the bright flares and outbursts from the Sun, its the perfect tool for examining the parts of the Sun weve been unable to explore in hard X-rays before now such as faint flares, or the quiet, inactive solar surface.In a recently published study led by Brian Grefenstette (California Institute of Technology), the team describes the purpose and initial results of NuSTARs first observations of the Sun.Solar MysteriesWhat is NuSTAR hoping to accomplish with its solar observations? There are two main questions that hard X-ray observations may help to answer.How are particles accelerated in

  14. Effect of cure cycle on enthalpy relaxation and post shrinkage in neat epoxy and epoxy composites

    DEFF Research Database (Denmark)

    Jensen, Martin; Jakobsen, Johnny

    2016-01-01

    The effect of cure cycle on enthalpy relaxation and warpage is studied for both neat epoxy and glass/epoxy composites. An approach for determining the enthalpy relaxation in the matrix of composite materials combining modulated differential scanning calorimetry and thermogravimetry is presented...

  15. Molecular design of an epoxy for cryogenic temperatures

    Science.gov (United States)

    Sawa, Fumio; Nishijima, Shigehiro; Okada, Toichi

    The mechanical and thermal properties of several epoxy resins were measured to obtain guidelines for the molecular design of an epoxy resin for cryogenic temperatures. Two types of epoxy resin with different numbers of epoxy groups were mixed (with different mixing ratios) and cured. Fracture toughness, flexural strength and thermal contraction of the hybrid epoxy resins were measured down to cryogenic temperatures. The results suggest that epoxies with larger molecular weights between crosslinkings relaxed stress at the crack tip, even at cryogenic temperatures. Intermolecular forces and stress relaxation at the crack tip were found to be important for high fracture toughness.

  16. The Gaia mission

    Science.gov (United States)

    Gaia Collaboration; Prusti, T.; de Bruijne, J. H. J.; Brown, A. G. A.; Vallenari, A.; Babusiaux, C.; Bailer-Jones, C. A. L.; Bastian, U.; Biermann, M.; Evans, D. W.; Eyer, L.; Jansen, F.; Jordi, C.; Klioner, S. A.; Lammers, U.; Lindegren, L.; Luri, X.; Mignard, F.; Milligan, D. J.; Panem, C.; Poinsignon, V.; Pourbaix, D.; Randich, S.; Sarri, G.; Sartoretti, P.; Siddiqui, H. I.; Soubiran, C.; Valette, V.; van Leeuwen, F.; Walton, N. A.; Aerts, C.; Arenou, F.; Cropper, M.; Drimmel, R.; Høg, E.; Katz, D.; Lattanzi, M. G.; O'Mullane, W.; Grebel, E. K.; Holland, A. D.; Huc, C.; Passot, X.; Bramante, L.; Cacciari, C.; Castañeda, J.; Chaoul, L.; Cheek, N.; De Angeli, F.; Fabricius, C.; Guerra, R.; Hernández, J.; Jean-Antoine-Piccolo, A.; Masana, E.; Messineo, R.; Mowlavi, N.; Nienartowicz, K.; Ordóñez-Blanco, D.; Panuzzo, P.; Portell, J.; Richards, P. J.; Riello, M.; Seabroke, G. M.; Tanga, P.; Thévenin, F.; Torra, J.; Els, S. G.; Gracia-Abril, G.; Comoretto, G.; Garcia-Reinaldos, M.; Lock, T.; Mercier, E.; Altmann, M.; Andrae, R.; Astraatmadja, T. L.; Bellas-Velidis, I.; Benson, K.; Berthier, J.; Blomme, R.; Busso, G.; Carry, B.; Cellino, A.; Clementini, G.; Cowell, S.; Creevey, O.; Cuypers, J.; Davidson, M.; De Ridder, J.; de Torres, A.; Delchambre, L.; Dell'Oro, A.; Ducourant, C.; Frémat, Y.; García-Torres, M.; Gosset, E.; Halbwachs, J.-L.; Hambly, N. C.; Harrison, D. L.; Hauser, M.; Hestroffer, D.; Hodgkin, S. T.; Huckle, H. E.; Hutton, A.; Jasniewicz, G.; Jordan, S.; Kontizas, M.; Korn, A. J.; Lanzafame, A. C.; Manteiga, M.; Moitinho, A.; Muinonen, K.; Osinde, J.; Pancino, E.; Pauwels, T.; Petit, J.-M.; Recio-Blanco, A.; Robin, A. C.; Sarro, L. M.; Siopis, C.; Smith, M.; Smith, K. W.; Sozzetti, A.; Thuillot, W.; van Reeven, W.; Viala, Y.; Abbas, U.; Abreu Aramburu, A.; Accart, S.; Aguado, J. J.; Allan, P. M.; Allasia, W.; Altavilla, G.; Álvarez, M. A.; Alves, J.; Anderson, R. I.; Andrei, A. H.; Anglada Varela, E.; Antiche, E.; Antoja, T.; Antón, S.; Arcay, B.; Atzei, A.; Ayache, L.; Bach, N.; Baker, S. G.; Balaguer-Núñez, L.; Barache, C.; Barata, C.; Barbier, A.; Barblan, F.; Baroni, M.; Barrado y Navascués, D.; Barros, M.; Barstow, M. A.; Becciani, U.; Bellazzini, M.; Bellei, G.; Bello García, A.; Belokurov, V.; Bendjoya, P.; Berihuete, A.; Bianchi, L.; Bienaymé, O.; Billebaud, F.; Blagorodnova, N.; Blanco-Cuaresma, S.; Boch, T.; Bombrun, A.; Borrachero, R.; Bouquillon, S.; Bourda, G.; Bouy, H.; Bragaglia, A.; Breddels, M. A.; Brouillet, N.; Brüsemeister, T.; Bucciarelli, B.; Budnik, F.; Burgess, P.; Burgon, R.; Burlacu, A.; Busonero, D.; Buzzi, R.; Caffau, E.; Cambras, J.; Campbell, H.; Cancelliere, R.; Cantat-Gaudin, T.; Carlucci, T.; Carrasco, J. M.; Castellani, M.; Charlot, P.; Charnas, J.; Charvet, P.; Chassat, F.; Chiavassa, A.; Clotet, M.; Cocozza, G.; Collins, R. S.; Collins, P.; Costigan, G.; Crifo, F.; Cross, N. J. G.; Crosta, M.; Crowley, C.; Dafonte, C.; Damerdji, Y.; Dapergolas, A.; David, P.; David, M.; De Cat, P.; de Felice, F.; de Laverny, P.; De Luise, F.; De March, R.; de Martino, D.; de Souza, R.; Debosscher, J.; del Pozo, E.; Delbo, M.; Delgado, A.; Delgado, H. E.; di Marco, F.; Di Matteo, P.; Diakite, S.; Distefano, E.; Dolding, C.; Dos Anjos, S.; Drazinos, P.; Durán, J.; Dzigan, Y.; Ecale, E.; Edvardsson, B.; Enke, H.; Erdmann, M.; Escolar, D.; Espina, M.; Evans, N. W.; Eynard Bontemps, G.; Fabre, C.; Fabrizio, M.; Faigler, S.; Falcão, A. J.; Farràs Casas, M.; Faye, F.; Federici, L.; Fedorets, G.; Fernández-Hernández, J.; Fernique, P.; Fienga, A.; Figueras, F.; Filippi, F.; Findeisen, K.; Fonti, A.; Fouesneau, M.; Fraile, E.; Fraser, M.; Fuchs, J.; Furnell, R.; Gai, M.; Galleti, S.; Galluccio, L.; Garabato, D.; García-Sedano, F.; Garé, P.; Garofalo, A.; Garralda, N.; Gavras, P.; Gerssen, J.; Geyer, R.; Gilmore, G.; Girona, S.; Giuffrida, G.; Gomes, M.; González-Marcos, A.; González-Núñez, J.; González-Vidal, J. J.; Granvik, M.; Guerrier, A.; Guillout, P.; Guiraud, J.; Gúrpide, A.; Gutiérrez-Sánchez, R.; Guy, L. P.; Haigron, R.; Hatzidimitriou, D.; Haywood, M.; Heiter, U.; Helmi, A.; Hobbs, D.; Hofmann, W.; Holl, B.; Holland, G.; Hunt, J. A. S.; Hypki, A.; Icardi, V.; Irwin, M.; Jevardat de Fombelle, G.; Jofré, P.; Jonker, P. G.; Jorissen, A.; Julbe, F.; Karampelas, A.; Kochoska, A.; Kohley, R.; Kolenberg, K.; Kontizas, E.; Koposov, S. E.; Kordopatis, G.; Koubsky, P.; Kowalczyk, A.; Krone-Martins, A.; Kudryashova, M.; Kull, I.; Bachchan, R. K.; Lacoste-Seris, F.; Lanza, A. F.; Lavigne, J.-B.; Le Poncin-Lafitte, C.; Lebreton, Y.; Lebzelter, T.; Leccia, S.; Leclerc, N.; Lecoeur-Taibi, I.; Lemaitre, V.; Lenhardt, H.; Leroux, F.; Liao, S.; Licata, E.; Lindstrøm, H. E. P.; Lister, T. A.; Livanou, E.; Lobel, A.; Löffler, W.; López, M.; Lopez-Lozano, A.; Lorenz, D.; Loureiro, T.; MacDonald, I.; Magalhães Fernandes, T.; Managau, S.; Mann, R. G.; Mantelet, G.; Marchal, O.; Marchant, J. M.; Marconi, M.; Marie, J.; Marinoni, S.; Marrese, P. M.; Marschalkó, G.; Marshall, D. J.; Martín-Fleitas, J. M.; Martino, M.; Mary, N.; Matijevič, G.; Mazeh, T.; McMillan, P. J.; Messina, S.; Mestre, A.; Michalik, D.; Millar, N. R.; Miranda, B. M. H.; Molina, D.; Molinaro, R.; Molinaro, M.; Molnár, L.; Moniez, M.; Montegriffo, P.; Monteiro, D.; Mor, R.; Mora, A.; Morbidelli, R.; Morel, T.; Morgenthaler, S.; Morley, T.; Morris, D.; Mulone, A. F.; Muraveva, T.; Musella, I.; Narbonne, J.; Nelemans, G.; Nicastro, L.; Noval, L.; Ordénovic, C.; Ordieres-Meré, J.; Osborne, P.; Pagani, C.; Pagano, I.; Pailler, F.; Palacin, H.; Palaversa, L.; Parsons, P.; Paulsen, T.; Pecoraro, M.; Pedrosa, R.; Pentikäinen, H.; Pereira, J.; Pichon, B.; Piersimoni, A. M.; Pineau, F.-X.; Plachy, E.; Plum, G.; Poujoulet, E.; Prša, A.; Pulone, L.; Ragaini, S.; Rago, S.; Rambaux, N.; Ramos-Lerate, M.; Ranalli, P.; Rauw, G.; Read, A.; Regibo, S.; Renk, F.; Reylé, C.; Ribeiro, R. A.; Rimoldini, L.; Ripepi, V.; Riva, A.; Rixon, G.; Roelens, M.; Romero-Gómez, M.; Rowell, N.; Royer, F.; Rudolph, A.; Ruiz-Dern, L.; Sadowski, G.; Sagristà Sellés, T.; Sahlmann, J.; Salgado, J.; Salguero, E.; Sarasso, M.; Savietto, H.; Schnorhk, A.; Schultheis, M.; Sciacca, E.; Segol, M.; Segovia, J. C.; Segransan, D.; Serpell, E.; Shih, I.-C.; Smareglia, R.; Smart, R. L.; Smith, C.; Solano, E.; Solitro, F.; Sordo, R.; Soria Nieto, S.; Souchay, J.; Spagna, A.; Spoto, F.; Stampa, U.; Steele, I. A.; Steidelmüller, H.; Stephenson, C. A.; Stoev, H.; Suess, F. F.; Süveges, M.; Surdej, J.; Szabados, L.; Szegedi-Elek, E.; Tapiador, D.; Taris, F.; Tauran, G.; Taylor, M. B.; Teixeira, R.; Terrett, D.; Tingley, B.; Trager, S. C.; Turon, C.; Ulla, A.; Utrilla, E.; Valentini, G.; van Elteren, A.; Van Hemelryck, E.; van Leeuwen, M.; Varadi, M.; Vecchiato, A.; Veljanoski, J.; Via, T.; Vicente, D.; Vogt, S.; Voss, H.; Votruba, V.; Voutsinas, S.; Walmsley, G.; Weiler, M.; Weingrill, K.; Werner, D.; Wevers, T.; Whitehead, G.; Wyrzykowski, Ł.; Yoldas, A.; Žerjal, M.; Zucker, S.; Zurbach, C.; Zwitter, T.; Alecu, A.; Allen, M.; Allende Prieto, C.; Amorim, A.; Anglada-Escudé, G.; Arsenijevic, V.; Azaz, S.; Balm, P.; Beck, M.; Bernstein, H.-H.; Bigot, L.; Bijaoui, A.; Blasco, C.; Bonfigli, M.; Bono, G.; Boudreault, S.; Bressan, A.; Brown, S.; Brunet, P.-M.; Bunclark, P.; Buonanno, R.; Butkevich, A. G.; Carret, C.; Carrion, C.; Chemin, L.; Chéreau, F.; Corcione, L.; Darmigny, E.; de Boer, K. S.; de Teodoro, P.; de Zeeuw, P. T.; Delle Luche, C.; Domingues, C. D.; Dubath, P.; Fodor, F.; Frézouls, B.; Fries, A.; Fustes, D.; Fyfe, D.; Gallardo, E.; Gallegos, J.; Gardiol, D.; Gebran, M.; Gomboc, A.; Gómez, A.; Grux, E.; Gueguen, A.; Heyrovsky, A.; Hoar, J.; Iannicola, G.; Isasi Parache, Y.; Janotto, A.-M.; Joliet, E.; Jonckheere, A.; Keil, R.; Kim, D.-W.; Klagyivik, P.; Klar, J.; Knude, J.; Kochukhov, O.; Kolka, I.; Kos, J.; Kutka, A.; Lainey, V.; LeBouquin, D.; Liu, C.; Loreggia, D.; Makarov, V. V.; Marseille, M. G.; Martayan, C.; Martinez-Rubi, O.; Massart, B.; Meynadier, F.; Mignot, S.; Munari, U.; Nguyen, A.-T.; Nordlander, T.; Ocvirk, P.; O'Flaherty, K. S.; Olias Sanz, A.; Ortiz, P.; Osorio, J.; Oszkiewicz, D.; Ouzounis, A.; Palmer, M.; Park, P.; Pasquato, E.; Peltzer, C.; Peralta, J.; Péturaud, F.; Pieniluoma, T.; Pigozzi, E.; Poels, J.; Prat, G.; Prod'homme, T.; Raison, F.; Rebordao, J. M.; Risquez, D.; Rocca-Volmerange, B.; Rosen, S.; Ruiz-Fuertes, M. I.; Russo, F.; Sembay, S.; Serraller Vizcaino, I.; Short, A.; Siebert, A.; Silva, H.; Sinachopoulos, D.; Slezak, E.; Soffel, M.; Sosnowska, D.; Straižys, V.; ter Linden, M.; Terrell, D.; Theil, S.; Tiede, C.; Troisi, L.; Tsalmantza, P.; Tur, D.; Vaccari, M.; Vachier, F.; Valles, P.; Van Hamme, W.; Veltz, L.; Virtanen, J.; Wallut, J.-M.; Wichmann, R.; Wilkinson, M. I.; Ziaeepour, H.; Zschocke, S.

    2016-11-01

    Gaia is a cornerstone mission in the science programme of the EuropeanSpace Agency (ESA). The spacecraft construction was approved in 2006, following a study in which the original interferometric concept was changed to a direct-imaging approach. Both the spacecraft and the payload were built by European industry. The involvement of the scientific community focusses on data processing for which the international Gaia Data Processing and Analysis Consortium (DPAC) was selected in 2007. Gaia was launched on 19 December 2013 and arrived at its operating point, the second Lagrange point of the Sun-Earth-Moon system, a few weeks later. The commissioning of the spacecraft and payload was completed on 19 July 2014. The nominal five-year mission started with four weeks of special, ecliptic-pole scanning and subsequently transferred into full-sky scanning mode. We recall the scientific goals of Gaia and give a description of the as-built spacecraft that is currently (mid-2016) being operated to achieve these goals. We pay special attention to the payload module, the performance of which is closely related to the scientific performance of the mission. We provide a summary of the commissioning activities and findings, followed by a description of the routine operational mode. We summarise scientific performance estimates on the basis of in-orbit operations. Several intermediate Gaia data releases are planned and the data can be retrieved from the Gaia Archive, which is available through the Gaia home page. http://www.cosmos.esa.int/gaia

  17. Totality eclipses of the Sun

    CERN Document Server

    Littmann, Mark; Willcox, Ken

    2008-01-01

    A total eclipse of the Sun is the most awesome sight in the heavens. Totality: Eclipses of the Sun takes you to eclipses of the past, present, and future, and lets you see - and feel - why people travel to the ends of the Earth to observe them. - ;A total eclipse of the Sun is the most awesome sight in the heavens. Totality: Eclipses of the Sun takes you to eclipses of the past, present, and future, and lets you see - and feel - why people travel to the ends of the Earth to observe them. Totality: Eclipses of the Sun is the best guide and reference book on solar eclipses ever written. It explains: how to observe them; how to photograph and videotape them; why they occur; their history and mythology; and future eclipses - when and where to see them. Totality also tells the remarkable story of how eclipses shocked scientists, revealed the workings of the Sun, and made Einstein famous. And the book shares the experiences and advice of many veteran eclipse observers. Totality: Eclipses of the Sun is profusely ill...

  18. Sun, UV Radiation and Your Eyes

    Science.gov (United States)

    ... Patient Stories Español Eye Health / Tips & Prevention Your Eyes and the Sun Sections The Sun, UV Radiation ... Safety Infographic The Sun, UV Radiation and Your Eyes Written by: David Turbert Aug. 28, 2014 Keep ...

  19. Clustering of Sun Exposure Measurements

    DEFF Research Database (Denmark)

    Have, Anna Szynkowiak; Larsen, Jan; Hansen, Lars Kai

    2002-01-01

    In a medically motivated Sun-exposure study, questionnaires concerning Sun-habits were collected from a number of subjects together with UV radiation measurements. This paper focuses on identifying clusters in the heterogeneous set of data for the purpose of understanding possible relations between...... Sun-habits exposure and eventually assessing the risk of skin cancer. A general probabilistic framework originally developed for text and Web mining is demonstrated to be useful for clustering of behavioral data. The framework combines principal component subspace projection with probabilistic...

  20. Coronal Mass Ejections: From Sun to Earth

    Science.gov (United States)

    Patsourakos, S.

    2016-06-01

    Coronal Mass Ejections (CMEs) are gigantic expulsions of magnetized plasmas from the solar corona into the interplanetary (IP) space. CMEs spawn ~ 1015 gr of mass and reach speeds ranging between several hundred to a few thousand km/s (e.g., Gopalswamy et al. 2009; Vourlidas et al. 2010). It takes 1-5 days for a CME to reach Earth. CMEs are one of the most energetic eruptive manifestations in the solar system and are major drivers of space weather via their magnetic fields and energetic particles, which are accelerated by CME-driven shocks. In this review we give a short account of recent, mainly observational, results on CMEs from the STEREO and SDO missions which include the nature of their pre-eruptive and eruptive configurations and the CME propagation from Sun to Earth. We conclude with a discussion of the exciting capabilities in CME studies that will soon become available from new solar and heliospheric instrumentation.

  1. Magnetic Patches in Internetwork Quiet Sun

    Science.gov (United States)

    De Wijn, Alfred; Lites, B.; Berger, T.; Shine, R.; Title, A.; Katsukawa, Y.; Tsuneta, S.; Suematsu, Y.; Shimizu, T.; Hinode Team

    2007-05-01

    We study strong flux elements in the quiet sun in the context of the nature of quiet-sun magnetism, its coupling to chromospheric, transition-region and coronal fields, and the nature of a local turbulent dynamo. Strong, kilogauss flux elements show up intermittently as small bright points in G-band and Ca II H images. Although bright points have been extensively studied in the magnetic network, internetwork magnetism has only come under scrutiny in recent years. A full spectrum of field strengths seems to be ubiquitously present in the internetwork at small spatial scales, with the stronger elements residing in intergranular lanes. De Wijn et al. (2005) found that bright points in quiet sun internetwork areas appear recurrently with varying intensity and horizontal motion within long-lived patches that outline cell patterns on mesogranular scales. They estimate that the "magnetic patches" have a mean lifetime of nine hours, much longer than granular timescales. We use multi-hour sequences of G-band and Ca II H images as well as magnetograms recorded by the Hinode satellite to follow up on their results. The larger field of view, the longer sequences, the addition of magnetograms, and the absence of atmospheric seeing allows us to better constrain the patch lifetime, to provide much improved statistics on IBP lifetime, to compare IBPs to network bright points, and to study field polarity of IBPs in patches and between nearby patches. Hinode is an international project supported by JAXA, NASA, PPARC and ESA. We are grateful to the Hinode team for all their efforts in the design, build and operation of the mission.

  2. Interhelioprobe Mission for Solar and Heliospheric Studies

    Science.gov (United States)

    Kuznetsov, Vladimir; Zelenyi, Lev; Zimovets, Ivan

    2016-07-01

    A new concept has been adopted for the Interhelioprobe mission intended for studying the inner heliosphere and the Sun at short distances and from out-of-ecliptic positions. In accordance with this concept, two identical SC spaced by a quarter of a period on heliocentric orbits inclined to the ecliptic plane in different directions will orbit the Sun, thus ensuring continuous out-of-ecliptic solar observations and measurements in the heliosphere. The scientific payload will comprise instruments for remote observations of the Sun (Optical photometer, Magnetograph, Chemical Composition Analyzer, EUV Imager-Spectrometer, Coronagraph, X-ray Imager, Heliospheric Imager, X-ray Polarimeter, and Gamma-Spectrometers) and in-situ measurements in the heliosphere (Solar Wind Ion Analyzer, Solar Wind Electron Analyzer, Solar Wind Plasma Analyzers, Energetic Particle Telescope, Neutron Detector, Magnetic Wave Complex, Magnetometer, and Radio Spectrometer Detector). The instruments will study the structure and dynamics of the magnetic fields and plasma flows in the polar regions of the Sun, solar flares and mass ejections, the heating of the solar corona and solar wind acceleration, acceleration and propagation of energetic particles in the Sun and heliosphere, the solar wind, as well as disturbances and ejections that come from the Sun to the Earth and control space weather in the near-Earth space. The schedule of the mission and the development status of the instruments and the spacecraft are provided.

  3. A new perspective on quiet Sun magnetism

    Institute of Scientific and Technical Information of China (English)

    LITES Bruce William

    2009-01-01

    The Hinode mission has provided us with a new, quantitative view of the magnetism of the quiet Sun. It has revealed that the quiet internetwork areas are blanketed by horizontal fields that appear at first sight to have more flux than the vertical fields resolved on the same 0.3″ size scale. These measurements point to the possibility that the horizontal fields might be the primary source of the "hidden turbulent flux" of the quiet Sun anticipated from Hanle effect depolarization. In this paper, evidence is presented suggesting that the "seething" horizontal fields observed by Harvey in 2007 and the horizontal fields revealed by Hinode are the same phenomenon. Because the seething fields appear to be of uniform fluctuation over the whole disk, the phenomenon is most likely not associated with the dynamo source of solar activity. Thus, the small-scale "hidden turbulent flux" lends support to the notion of a local solar dynamo acting on granular sizes and time scales.

  4. Fluorinated Alkyl Ether Epoxy Resin Compositions and Applications Thereof

    Science.gov (United States)

    Wohl, Christopher J. (Inventor); Connell, John W. (Inventor); Smith, Joseph G. (Inventor); Siochi, Emilie J. (Inventor); Gardner, John M. (Inventor); Palmieri, Frank M. (Inventor)

    2017-01-01

    Epoxy resin compositions prepared using amino terminated fluoro alkyl ethers. The epoxy resin compositions exhibit low surface adhesion properties making them useful as coatings, paints, moldings, adhesives, and fiber reinforced composites.

  5. Testing Tensile and Shear Epoxy Strength at Cryogenic Temperatures

    Science.gov (United States)

    Alberts, S. J.; Doehne, C. J.; Johnson, W. L.

    2017-01-01

    This paper covers cryogenic, tensile testing and research completed on a number of epoxies used in cryogenic applications. Epoxies are used in many different applications; however, this research focused on the use of epoxy used to bond MLI standoffs to cryogenic storage tanks and the loads imparted to the tank through the MLI. To conduct testing, samples were made from bare stainless steel, aluminum and primed aluminum. Testing involved slowly cooling test samples with liquid nitrogen then applying gradually increasing tensile loads to the epoxy. The testing evaluated the strength and durability of epoxies at cryogenic temperatures and serves as a base for future testing. The results of the tests showed that some epoxies withstood the harsh conditions while others failed. The two epoxies yielding the best results were Masterbond EP29LPSP and Scotch Weld 2216. For all metal surfaces tested, both epoxies had zero failures for up to 11.81 kg of mass.

  6. Prototype of sun projector device

    Science.gov (United States)

    Ihsan; Dermawan, B.

    2016-11-01

    One way to introduce astronomy to public, including students, can be handled by solar observation. The widely held device for this purpose is coelostat and heliostat. Besides using filter attached to a device such as telescope, it is safest to use indirect way for observing the Sun. The main principle of the indirect way is deflecting the sun light and projecting image of the sun on a screen. We design and build a simple and low-cost astronomical device, serving as a supplement to increase public service, especially for solar observation. Without using any digital and intricate supporting equipment, people can watch and relish image of the Sun in comfortable condition, i.e. in a sheltered or shady place. Here we describe a design and features of our prototype of the device, which still, of course, has some limitations. In the future, this prototype can be improved for more efficient and useful applications.

  7. SOHO Mission Science Briefing

    Science.gov (United States)

    1995-01-01

    Footage shows the SOHO Mission Pre-Launch Science Briefing. The moderator of the conference is Fred Brown, NASA/GSFC Public Affairs, introduces the panel members. Included are Professor Roger Bonnet, Director ESA Science Program, Dr. Wesley Huntress, Jr., NASA Associate Administrator for Space Science and Dr. Vicente Domingo, ESA SOHO Project Scientist. Also present are several members from the SOHO Team: Dr. Richard Harrison, Art Poland, and Phillip Scherrer. The discussions include understanding the phenomena of the sun, eruption of gas clouds into the atmosphere, the polishing of the mirrors for the SOHO satellite, artificial intelligence in the telescopes, and the launch and operating costs. The panel members are also seen answering questions from various NASA Centers and Paris.

  8. Chromium Ions Improve Moisure Resistance of Epoxy Resins

    Science.gov (United States)

    St. Clair, A. K.; St. Clair, T. L.; Stoakley, D. M.; Singh, J. J.; Sprinkle, D. R.

    1986-01-01

    Broad spectrum of thermosetting epoxy resins used on commercial and military aircraft, primarily as composite matrices and adhesives. In new technique, chromium-ion containing epoxy with improved resistance to moisture produced where chromium ions believed to prevent absorption of water molecules by coordinating themselves to hydroxyl groups on epoxy chain. Anticipated that improved epoxy formulation useful as composite matrix resin, adhesive, or casting resin for applications on commercial and advanced aircraft. Improvement made without sacrifice in mechanical properties of polymer.

  9. Thermal properties of epoxy composites filled with boric acid

    Science.gov (United States)

    Visakh, P. M.; Nazarenko, O. B.; Amelkovich, Yu A.; Melnikova, T. V.

    2015-04-01

    The thermal properties of epoxy composites filled with boric acid fine powder at different percentage were studied. Epoxy composites were prepared using epoxy resin ED-20, boric acid as flame-retardant filler, hexamethylenediamine as a curing agent. The prepared samples and starting materials were examined using methods of thermal analysis, scanning electron microscopy and infrared spectroscopy. It was found that the incorporation of boric acid fine powder enhances the thermal stability of epoxy composites.

  10. STS-40 Mission Insignia

    Science.gov (United States)

    1990-01-01

    The STS-40 patch makes a contemporary statement focusing on human beings living and working in space. Against a background of the universe, seven silver stars, interspersed about the orbital path of Columbia, represent the seven crew members. The orbiter's flight path forms a double-helix, designed to represent the DNA molecule common to all living creatures. In the words of a crew spokesman, ...(the helix) affirms the ceaseless expansion of human life and American involvement in space while simultaneously emphasizing the medical and biological studies to which this flight is dedicated. Above Columbia, the phrase Spacelab Life Sciences 1 defines both the Shuttle mission and its payload. Leonardo Da Vinci's Vitruvian man, silhouetted against the blue darkness of the heavens, is in the upper center portion of the patch. With one foot on Earth and arms extended to touch Shuttle's orbit, the crew feels, he serves as a powerful embodiment of the extension of human inquiry from the boundaries of Earth to the limitless laboratory of space. Sturdily poised amid the stars, he serves to link scentists on Earth to the scientists in space asserting the harmony of efforts which produce meaningful scientific spaceflight missions. A brilliant red and yellow Earth limb (center) links Earth to space as it radiates from a native American symbol for the sun. At the frontier of space, the traditional symbol for the sun vividly links America's past to America's future, the crew states. Beneath the orbiting Shuttle, darkness of night rests peacefully over the United States. Drawn by artist Sean Collins, the STS 40 Space Shuttle patch was designed by the crewmembers for the flight.

  11. RADIATION EFFECTS ON EPOXY CARBON FIBER COMPOSITE

    Energy Technology Data Exchange (ETDEWEB)

    Hoffman, E

    2008-05-30

    Carbon fiber-reinforced bisphenol-A epoxy matrix composite was evaluated for gamma radiation resistance. The composite was exposed to total gamma doses of 50, 100, and 200 Mrad. Irradiated and baseline samples were tested for tensile strength, hardness and evaluated using FTIR (Fourier transform infrared) spectroscopy and DSC (differential scanning calorimetry) for structural changes. Scanning electron microscopy was used to evaluate microstructural behavior. Mechanical testing of the composite bars revealed no apparent change in modulus, strain to failure, or fracture strength after exposures. However, testing of only the epoxy matrix revealed changes in hardness, thermal properties, and FTIR results with increasing gamma irradiation. The results suggest the epoxy within the composite can be affected by exposure to gamma irradiation.

  12. Thermal Conductivity of Carbon Nanoreinforced Epoxy Composites

    Directory of Open Access Journals (Sweden)

    C. Kostagiannakopoulou

    2016-01-01

    Full Text Available The present study attempts to investigate the influence of multiwalled carbon nanotubes (MWCNTs and graphite nanoplatelets (GNPs on thermal conductivity (TC of nanoreinforced polymers and nanomodified carbon fiber epoxy composites (CFRPs. Loading levels from 1 to 3% wt. of MWCNTs and from 1 to 15% wt. of GNPs were used. The results indicate that TC of nanofilled epoxy composites increased with the increase of GNP content. Quantitatively, 176% and 48% increase of TC were achieved in nanoreinforced polymers and nanomodified CFRPs, respectively, with the addition of 15% wt. GNPs into the epoxy matrix. Finally, micromechanical models were applied in order to predict analytically the TC of polymers and CFRPs. Lewis-Nielsen model with optimized parameters provides results very close to the experimental ones in the case of polymers. As far as the composites are concerned, the Hashin and Clayton models proved to be sufficiently accurate for the prediction at lower filler contents.

  13. Unanticipated Effects of Epoxy Impregnating Transformers

    Energy Technology Data Exchange (ETDEWEB)

    SANCHEZ,ROBERT O.; ARCHER,WENDEL E.

    2000-08-23

    Many Sandia components for military applications are designed for a 20-year life. In order to determine if magnetic components meet that requirement, the parts are subjected to selected destructive tests. This paper reviews the re-design of a power transformer and the tests required to prove-in the re-design. The re-design included replacing the Epon 828/Mica/methylenedianiline (curing agent Z) epoxy encapsulant with a recent Sandia National Laboratory (SNL) developed epoxy encapsulant. The new encapsulant reduces the Environmental Safety and Health (ES and H) hazards. Life testing of this re-designed transformer generated failures; an open secondary winding. An experimental program to determine the cause of the broken wires and an improved design to eliminate the problem was executed. This design weakness was corrected by reverting to the hazardous epoxy system.

  14. Atomistic modeling of thermomechanical properties of SWNT/Epoxy nanocomposites

    Science.gov (United States)

    Fasanella, Nicholas; Sundararaghavan, Veera

    2015-09-01

    Molecular dynamics simulations are performed to compute thermomechanical properties of cured epoxy resins reinforced with pristine and covalently functionalized carbon nanotubes. A DGEBA-DDS epoxy network was built using the ‘dendrimer’ growth approach where 75% of available epoxy sites were cross-linked. The epoxy model is verified through comparisons to experiments, and simulations are performed on nanotube reinforced cross-linked epoxy matrix using the CVFF force field in LAMMPS. Full stiffness matrices and linear coefficient of thermal expansion vectors are obtained for the nanocomposite. Large increases in stiffness and large decreases in thermal expansion were seen along the direction of the nanotube for both nanocomposite systems when compared to neat epoxy. The direction transverse to nanotube saw a 40% increase in stiffness due to covalent functionalization over neat epoxy at 1 K whereas the pristine nanotube system only saw a 7% increase due to van der Waals effects. The functionalized SWNT/epoxy nanocomposite showed an additional 42% decrease in thermal expansion along the nanotube direction when compared to the pristine SWNT/epoxy nanocomposite. The stiffness matrices are rotated over every possible orientation to simulate the effects of an isotropic system of randomly oriented nanotubes in the epoxy. The randomly oriented covalently functionalized SWNT/Epoxy nanocomposites showed substantial improvements over the plain epoxy in terms of higher stiffness (200% increase) and lower thermal expansion (32% reduction). Through MD simulations, we develop means to build simulation cells, perform annealing to reach correct densities, compute thermomechanical properties and compare with experiments.

  15. 40 CFR 721.3140 - Vinyl epoxy ester.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Vinyl epoxy ester. 721.3140 Section... Substances § 721.3140 Vinyl epoxy ester. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance vinyl epoxy ester (PMN P-85-527) is subject to reporting under...

  16. Effect of Viscoelasticity on Adhesion of Bioinspired Micropatterned Epoxy Surfaces

    NARCIS (Netherlands)

    Castellanos, G.; Arzt, E.; Kamperman, M.M.G.

    2011-01-01

    The effect of viscoelasticity on adhesion was investigated for micropatterned epoxy surfaces and compared to nonpatterned surfaces. A two-component epoxy system was used to produce epoxy compositions with different viscoelastic properties. Pillar arrays with flat punch tip geometries were fabricated

  17. 40 CFR 721.3135 - Phosphorous modified epoxy resin (generic).

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Phosphorous modified epoxy resin... Specific Chemical Substances § 721.3135 Phosphorous modified epoxy resin (generic). (a) Chemical substance... phosphorous modified epoxy resin (PMNs P-00-992 and P-01-471) is subject to reporting under this section...

  18. 40 CFR 721.2752 - Epoxy resin containing phosphorus (generic).

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Epoxy resin containing phosphorus... Specific Chemical Substances § 721.2752 Epoxy resin containing phosphorus (generic). (a) Chemical substance... epoxy resin containing phosphorus (PMN P-00-912) is subject to reporting under this section for...

  19. Aluminum Rich Epoxy Primer for Ground and Air Vehicles

    Science.gov (United States)

    2017-03-01

    UNCLASSIFIED DOCUMENT Aluminum Rich Epoxy Primer for Ground and Air Vehicles Monthly Technical Report for the Period: January 20, 2017...Objective: To further develop the Aluminum Rich Epoxy Primer systems for Air and Ground Vehicles while addressing the objective requirements... Epoxy Primers in order to afford a lower initial viscosity allowing for better application properties; lower VOC; and the incorporation of various

  20. 40 CFR 721.10113 - Thioether epoxy (generic).

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Thioether epoxy (generic). 721.10113... Substances § 721.10113 Thioether epoxy (generic). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as thioether epoxy (PMN P-04-547) is subject to...

  1. Compatibility of the Radio Frequency Mass Gauge with Graphite-Epoxy Composite Tanks

    Science.gov (United States)

    Zimmerli, G. A.; Mueller, C. H.

    2015-01-01

    The radio frequency mass gauge (RFMG) is a low-gravity propellant quantity gauge being developed at NASA for possible use in long-duration space missions utilizing cryogenic propellants. As part of the RFMG technology development process, we evaluated the compatibility of the RFMG with a graphite-epoxy composite material used to construct propellant tanks. The key material property that can affect compatibility with the RFMG is the electrical conductivity. Using samples of 8552/IM7 graphite-epoxy composite, we characterized the resistivity and reflectivity over a range of frequencies. An RF impedance analyzer was used to characterize the out-of-plane electrical properties (along the sample thickness) in the frequency range 10 to 1800 MHZ. The resistivity value at 500 MHz was 4.8 ohm-cm. Microwave waveguide measurements of samples in the range 1.7 - 2.6 GHz, performed by inserting the samples into a WR-430 waveguide, showed reflectivity values above 98%. Together, these results suggested that a tank constructed from graphite/epoxy composite would produce good quality electromagnetic tank modes, which is needed for the RFMG. This was verified by room-temperature measurements of the electromagnetic modes of a 2.4 m diameter tank constructed by Boeing from similar graphite-epoxy composite material. The quality factor Q of the tank electromagnetic modes, measured via RF reflection measurements from an antenna mounted in the tank, was typically in the range 400 less than Q less than 3000. The good quality modes observed in the tank indicate that the RFMG is compatible with graphite-epoxy tanks, and thus the RFMG could be used as a low-gravity propellant quantity gauge in such tanks filled with cryogenic propellants.

  2. Control of pore size in epoxy systems.

    Energy Technology Data Exchange (ETDEWEB)

    Sawyer, Patricia Sue; Lenhart, Joseph Ludlow (North Dakota State University, Fargo, ND); Lee, Elizabeth (North Dakota State University, Fargo, ND); Kallam, Alekhya (North Dakota State University, Fargo, ND); Majumdar, Partha (North Dakota State University, Fargo, ND); Dirk, Shawn M.; Gubbins, Nathan; Chisholm, Bret J. (North Dakota State University, Fargo, ND); Celina, Mathias Christopher; Bahr, James (North Dakota State University, Fargo, ND); Klein, Robert J.

    2009-01-01

    Both conventional and combinatorial approaches were used to study the pore formation process in epoxy based polymer systems. Sandia National Laboratories conducted the initial work and collaborated with North Dakota State University (NDSU) using a combinatorial research approach to produce a library of novel monomers and crosslinkers capable of forming porous polymers. The library was screened to determine the physical factors that control porosity, such as porogen loading, polymer-porogen interactions, and polymer crosslink density. We have identified the physical and chemical factors that control the average porosity, pore size, and pore size distribution within epoxy based systems.

  3. Epoxy-based carbon nanotubes reinforced composites

    CSIR Research Space (South Africa)

    Kesavan Pillai, Sreejarani

    2011-04-01

    Full Text Available ). After curing the composite film system, the substrate was etched from the backside by deep reactive ion etching (DRIE) which left a circular thin film on the rigid substrate with a hole 8 mm in diameter. Extensive examination of the CNT... treatment or plasma oxidation to improve interfacial bonding and dispersion of nanotubes in the epoxy matrix. CVD-grown MWCNTs with average diameter of 13 nm and length of 10 ?m, epoxy resin (YD 128) and hardener (TH 432) were used in the study. The CNTs...

  4. High Temperature Epoxy Nanocomposites for Aerospace Applications

    Science.gov (United States)

    2009-06-10

    epoxy-clay nanocomposites were prepared by dispersing imidazolium- modified clays in diglycidyl ether of bisphenol A ( DGEBA ) mixture by performing...functionalized anionic clay was vigorously mixed for 2h with difunctional epoxy resin ( DGEBA ) that contained small fraction of reactive diluent 1,4...the neat DGEBA resin to increase from ~300°C to ~330°C in the 2 wt% NLDH nanocomposite at 10°C/min heating rate, while it increases from ~305°C in

  5. Kevlar 49/Epoxy COPV Aging Evaluation

    Science.gov (United States)

    Sutter, James K.; Salem, Jonathan L.; Thesken, John C.; Russell, Richard W.; Littell, Justin; Ruggeri, Charles; Leifeste, Mark R.

    2008-01-01

    NASA initiated an effort to determine if the aging of Kevlar 49/Epoxy composite overwrapped pressure vessels (COPV) affected their performance. This study briefly reviews the history and certification of composite pressure vessels employed on NASA Orbiters. Tests to evaluate overwrap tensile strength changes compared 30 year old samples from Orbiter vessels to new Kevlar/Epoxy pressure vessel materials. Other tests include transverse compression and thermal analyses (glass transition and moduli). Results from these tests do not indicate a noticeable effect due to aging of the overwrap materials.

  6. Luminous Efficient Compositions Based on Epoxy Resin

    Directory of Open Access Journals (Sweden)

    R.S. Palaiah

    2006-07-01

    Full Text Available Magnesium/sodium nitrate illuminating compositions with epoxy resin - E 605 have beenstudied for luminosity and luminous efficiency by varying fuel oxidizer ratio and binder content.The compositions have been evaluated for impact and friction sensitivities, burn rate, thermalcharacteristics, and mechanical properties. Flame temperature and combustion products areevaluated theoretically by using REAL program. Experimental results show that, luminosity,burn rate, and calorimetric value are higher for polyester resin-based compositions. The highluminous efficiency composition is achieved with magnesium/sodium nitrate ratio of 70/30 with4 per cent epoxy resin.

  7. Interphase tailoring in graphite-epoxy composites

    Science.gov (United States)

    Subramanian, R. V.; Sanadi, A. R.; Crasto, A. S.

    1988-01-01

    The fiber-matrix interphase in graphite fiber-epoxy matrix composites is presently modified through the electrodeposition of a coating of the polymer poly(styrene-comaleic anhydride), or 'SMA' on the graphite fibers; optimum conditions have been established for the achievement of the requisite thin, uniform coatings, as verified by SEM. A single-fiber composite test has shown the SMA coating to result in an interfacial shear strength to improve by 50 percent over commercially treated fibers without sacrifice in impact strength. It is suggested that the epoxy resin's superior penetration into the SMA interphase results in a tougher fiber/matrix interface which possesses intrinsic energy-absorbing mechanisms.

  8. STS-78 Mission Insignia

    Science.gov (United States)

    1996-01-01

    The STS-78 patch links past with present to tell the story of its mission and science through a design imbued with the strength and vitality of the 2-dimensional art of North America's northwest coast Indians. Central to the design is the space Shuttle whose bold lines and curves evoke the Indian image for the eagle, a native American symbol of power and prestige as well as the national symbol of the United States. The wings of the Shuttle suggest the wings of the eagle whose feathers, indicative of peace and friendship in Indian tradition, are captured by the U forms, a characteristic feature of Northwest coast Indian art. The nose of the Shuttle is the strong downward curve of the eagle's beak, and the Shuttle's forward windows, the eagle's eyes, represented through the tapered S forms again typical of this Indian art form. The basic black and red atoms orbiting the mission number recall the original NASA emblem while beneath, utilizing Indian ovoid forms, the major mission scientific experiment package LMS (Life and Materials Sciences) housed in the Shuttle's cargo bay is depicted in a manner reminiscent of totem-pole art. This image of a bird poised for flight, so common to Indian art, is counterpointed by an equally familiar Tsimshian Indian symbol, a pulsating sun with long hyperbolic rays, the symbol of life. Within each of these rays are now encased crystals, the products of this mission's 3 major, high-temperature materials processing furnaces. And as the sky in Indian lore is a lovely open country, home of the Sun Chief and accessible to travelers through a hole in the western horizon, so too, space is a vast and beckoning landscape for explorers launched beyond the horizon. Beneath the Tsimshian sun, the colors of the earth limb are appropriately enclosed by a red border representing life to the Northwest coast Indians. The Indian colors of red, navy blue, white, and black pervade the STS-78 path. To the right of the Shuttle-eagle, the constellation

  9. Hinode, the Sun, and public outreach

    Science.gov (United States)

    Yaji, K.; Tonooka, H.; Shimojo, M.; Tokimasa, N.; Suzuki, D.; Nakamichi, A.; Shimoikura, I.

    2015-03-01

    have continued various and constant EPO activities for the public use of Hinode data and have been giving intense impacts and high interest to the public. As the result, our activities contribute in further extension of Hinode Mission. Those are quite unique and would be reference of other similar ones. Hinode is now operating and solar activities might get more higher. As long as SUN RISE, we would GO FORWARD!!

  10. Solar composition from the Genesis Discovery Mission.

    Science.gov (United States)

    Burnett, D S; Team, Genesis Science

    2011-11-29

    Science results from the Genesis Mission illustrate the major advantages of sample return missions. (i) Important results not otherwise obtainable except by analysis in terrestrial laboratories: the isotopic compositions of O, N, and noble gases differ in the Sun from other inner solar system objects. The N isotopic composition is the same as that of Jupiter. Genesis has resolved discrepancies in the noble gas data from solar wind implanted in lunar soils. (ii) The most advanced analytical instruments have been applied to Genesis samples, including some developed specifically for the mission. (iii) The N isotope result has been replicated with four different instruments.

  11. SunShot Initiative Portfolio Book 2014

    Energy Technology Data Exchange (ETDEWEB)

    Solar Energy Technologies Office

    2014-05-01

    The 2014 SunShot Initiative Portfolio Book outlines the progress towards the goals outlined in the SunShot Vision Study. Contents include overviews of each of SunShot’s five subprogram areas, as well as a description of every active project in the SunShot’s project portfolio as of May 2014.

  12. Characterization of Epoxy Functionalized Graphite Nanoparticles and the Physical Properties of Epoxy Matrix Nanocomposites

    Science.gov (United States)

    Miller, Sandi G.; Bauer, Jonathan L.; Maryanski, Michael J.; Heimann, Paula J.; Barlow, Jeremy P.; Gosau, Jan-Michael; Allred, Ronald E.

    2010-01-01

    This work presents a novel approach to the functionalization of graphite nanoparticles. The technique provides a mechanism for covalent bonding between the filler and matrix, with minimal disruption to the sp2 hybridization of the pristine graphene sheet. Functionalization proceeded by covalently bonding an epoxy monomer to the surface of expanded graphite, via a coupling agent, such that the epoxy concentration was measured as approximately 4 wt.%. The impact of dispersing this material into an epoxy resin was evaluated with respect to the mechanical properties and electrical conductivity of the graphite-epoxy nanocomposite. At a loading as low as 0.5 wt.%, the electrical conductivity was increased by five orders of magnitude relative to the base resin. The material yield strength was increased by 30% and Young s modulus by 50%. These results were realized without compromise to the resin toughness.

  13. Effect of Liquid-Crystalline Epoxy Backbone Structure on Thermal Conductivity of Epoxy-Alumina Composites

    Science.gov (United States)

    Giang, Thanhkieu; Kim, Jinhwan

    2017-01-01

    In a series of papers published recently, we clearly demonstrated that the most important factor governing the thermal conductivity of epoxy-Al2O3 composites is the backbone structure of the epoxy. In this study, three more epoxies based on diglycidyl ester-terminated liquid-crystalline epoxy (LCE) have been synthesized to draw conclusions regarding the effect of the epoxy backbone structure on the thermal conductivity of epoxy-alumina composites. The synthesized structures were characterized by proton nuclear magnetic resonance (1H-NMR) and Fourier-transform infrared (FT-IR) spectroscopy. Differential scanning calorimetry, thermogravimetric analysis, and optical microscopy were also employed to examine the thermal and optical properties of the synthesized LCEs and the cured composites. All three LCE resins exhibited typical liquid-crystalline behaviors: clear solid crystalline state below the melting temperature ( T m), sharp crystalline melting at T m, and transition to nematic phase above T m with consequent isotropic phase above the isotropic temperature ( T i). The LCE resins displayed distinct nematic liquid-crystalline phase over a wide temperature range and retained liquid-crystalline phase after curing, with high thermal conductivity of the resulting composite. The thermal conductivity values ranged from 3.09 W/m-K to 3.89 W/m-K for LCE-Al2O3 composites with 50 vol.% filler loading. The steric effect played a governing role in the difference. The neat epoxy resin thermal conductivity was obtained as 0.35 W/m-K to 0.49 W/m-K based on analysis using the Agari-Uno model. The results clearly support the objective of this study in that the thermal conductivity of the LCE-containing networks strongly depended on the epoxy backbone structure and the degree of ordering in the cured network.

  14. The Gaia mission

    CERN Document Server

    ,

    2016-01-01

    Gaia is a cornerstone mission in the science programme of the European Space Agency (ESA). The spacecraft construction was approved in 2006, following a study in which the original interferometric concept was changed to a direct-imaging approach. Both the spacecraft and the payload were built by European industry. The involvement of the scientific community focusses on data processing for which the international Gaia Data Processing and Analysis Consortium (DPAC) was selected in 2007. Gaia was launched on 19 December 2013 and arrived at its operating point, the second Lagrange point of the Sun-Earth-Moon system, a few weeks later. The commissioning of the spacecraft and payload was completed on 19 July 2014. The nominal five-year mission started with four weeks of special, ecliptic-pole scanning and subsequently transferred into full-sky scanning mode. We recall the scientific goals of Gaia and give a description of the as-built spacecraft that is currently (mid-2016) being operated to achieve these goals. We...

  15. Adhesion between coating layers based on epoxy and silicone

    DEFF Research Database (Denmark)

    Svendsen, Jacob R.; Kontogeorgis, Georgios; Kiil, Søren

    2007-01-01

    The adhesion between a silicon tie-coat and epoxy primers, used in marine coating systems, has been studied in this work. Six epoxy coatings (with varying chain lengths of the epoxy resins), some of which have shown problems with adhesion to the tie-coat during service life, have been considered....... The experimental investigation includes measurements of the surface tension of the tie-coat and the critical surface tensions of the epoxies, topographic investigation of the surfaces of cured epoxy coatings via atomic force microscopy (AFM), and pull-off tests for investigating the strength of adhesion...... to the silicon/epoxy systems. Calculations for determining the roughness factor of the six epoxy coatings (based on the AFM topographies) and the theoretical work of adhesion have been carried out. The coating surfaces are also characterized based on the van Oss-Good theory. Previous studies on the modulus...

  16. Thermal expansion and swelling of cured epoxy resin used in graphite/epoxy composite materials

    Science.gov (United States)

    Adamson, M. J.

    1980-01-01

    The paper presents results of experiments in which the thermal expansion and swelling behavior of an epoxy resin system and two graphite/epoxy composite systems exposed to water were measured. It was found that the cured epoxy resin swells by an amount slightly less than the volume of the absorbed water and that the swelling efficiency of the water varies with the moisture content of the polymer. Additionally, the thermal expansion of cured epoxy resin that is saturated with water is observed to be more than twice that of dry resin. Results also indicate that cured resin that is saturated with 7.1% water at 95 C will rapidly increase in moisture content to 8.5% when placed in 1 C water. The mechanism for this phenomenon, termed reverse thermal effect, is described in terms of a slightly modified free-volume theory in conjunction with the theory of polar molecule interaction. Nearly identical behavior was observed in two graphite/epoxy composite systems, thus establishing that this behavior may be common to all cured epoxy resins.

  17. Development and characterization of epoxy syntactic foam filled with epoxy hollow spheres

    Directory of Open Access Journals (Sweden)

    2011-07-01

    Full Text Available The present study focuses on the development and characterization of epoxy syntactic foam filled with epoxy hollow spheres (ESF/EHoS. The epoxy syntactic foam (ESF was produced by embedding epoxy hollow spheres (EHoS into a mixture of epoxy-hardener and 3% KOH solution. An innovative approach and simple procedure was implemented in the preparation of the EHoS where expanded polystyrene (EPS beads were used as initiation material. The EPS beads were coated with the epoxy resin and these coated EPS beads were later cured and post-cured at high temperature which will also shrink the EPS beads thus producing a hollow structure. The physical and compressive properties of the developed ESF were characterized. The progressive collapse of the syntactic foam was monitored in real-time with respect to percentage of strain during a compression test. Results also indicated that the (ESF/EHoS showed similar deformation pattern with other types of syntactic foams which exhibited the common three regions of deformations.

  18. Synthesis and application of epoxy starch derivatives

    NARCIS (Netherlands)

    Huijbrechts, A.M.L.; Haar, ter R.; Schols, H.A.; Franssen, M.C.R.; Boeriu, C.G.; Sudhölter, E.J.R.

    2010-01-01

    Epoxy starch derivatives were synthesized by epoxidation of allylated starch. The reaction was performed with low substituted 1-allyloxy-2-hydroxypropyl-waxy maize starch (AHP-WMS; degree of substitution (DS) of 0.23) using hydrogen peroxide and acetonitrile Via a two step spectrophotometric assay,

  19. Synthesis and application of epoxy starch derivatives

    NARCIS (Netherlands)

    Huijbrechts, A.M.L.; Haar, ter R.; Schols, H.A.; Franssen, M.C.R.; Boeriu, C.G.; Sudhölter, E.J.R.

    2010-01-01

    Epoxy starch derivatives were synthesized by epoxidation of allylated starch. The reaction was performed with low substituted 1-allyloxy-2-hydroxypropyl-waxy maize starch (AHP-WMS; degree of substitution (DS) of 0.23) using hydrogen peroxide and acetonitrile Via a two step spectrophotometric assay,

  20. Epoxy adhesive plays crucial role at CERN

    CERN Multimedia

    2006-01-01

    "Epoxy adhesives are set to play a vital role in Europe's biggest-ever scientific experiment at the European Centre for Nuclear Research (CERN) in Geneva, Switzerland, thereby helping scientists gain a better understanding of the origins of the universe." (1 page)

  1. Epoxy adhesive plays crucial role at CERN

    CERN Multimedia

    2007-01-01

    "Epoxy adhesives are set to play a vital role in Europe's biggest-ever scientific experiment at the European Centrefor Nuclear Research (CERN) in Geneva, Switzerland, thereby helping scientists gain a better understanding of the origins of the universe." (1/2 page)

  2. Earth's Heat Source - The Sun

    CERN Document Server

    Manuel, Oliver K

    2009-01-01

    The Sun encompasses planet Earth, supplies the heat that warms it, and even shakes it. The United Nation Intergovernmental Panel on Climate Change (IPCC) assumed that solar influence on our climate is limited to changes in solar irradiance and adopted the consensus opinion of a Hydrogen-filled Sun, the Standard Solar Model (SSM). They did not consider the alternative solar model and instead adopted another consensus opinion: Anthropogenic greenhouse gases play a dominant role in climate change. The SSM fails to explain the solar wind, solar cycles, and the empirical link of solar surface activity with Earth changing climate. The alternative solar model, that was molded from an embarrassingly large number of unexpected observations revealed by space-age measurements since 1959, explains not only these puzzles but also how closely linked interactions between the Sun and its planets and other celestial bodies induce turbulent cycles of secondary solar characteristics that significantly affect Earth climate.

  3. KEPLER Mission: development and overview.

    Science.gov (United States)

    Borucki, William J

    2016-03-01

    The Kepler Mission is a space observatory launched in 2009 by NASA to monitor 170,000 stars over a period of four years to determine the frequency of Earth-size and larger planets in and near the habitable zone of Sun-like stars, the size and orbital distributions of these planets, and the types of stars they orbit. Kepler is the tenth in the series of NASA Discovery Program missions that are competitively-selected, PI-directed, medium-cost missions. The Mission concept and various instrument prototypes were developed at the Ames Research Center over a period of 18 years starting in 1983. The development of techniques to do the 10 ppm photometry required for Mission success took years of experimentation, several workshops, and the exploration of many 'blind alleys' before the construction of the flight instrument. Beginning in 1992 at the start of the NASA Discovery Program, the Kepler Mission concept was proposed five times before its acceptance for mission development in 2001. During that period, the concept evolved from a photometer in an L2 orbit that monitored 6000 stars in a 50 sq deg field-of-view (FOV) to one that was in a heliocentric orbit that simultaneously monitored 170,000 stars with a 105 sq deg FOV. Analysis of the data to date has detected over 4600 planetary candidates which include several hundred Earth-size planetary candidates, over a thousand confirmed planets, and Earth-size planets in the habitable zone (HZ). These discoveries provide the information required for estimates of the frequency of planets in our galaxy. The Mission results show that most stars have planets, many of these planets are similar in size to the Earth, and that systems with several planets are common. Although planets in the HZ are common, many are substantially larger than Earth.

  4. Rosetta mission operations for landing

    Science.gov (United States)

    Accomazzo, Andrea; Lodiot, Sylvain; Companys, Vicente

    2016-08-01

    The International Rosetta Mission of the European Space Agency (ESA) was launched on 2nd March 2004 on its 10 year journey to comet Churyumov-Gerasimenko and has reached it early August 2014. The main mission objectives were to perform close observations of the comet nucleus throughout its orbit around the Sun and deliver the lander Philae to its surface. This paper describers the activities at mission operations level that allowed the landing of Philae. The landing preparation phase was mainly characterised by the definition of the landing selection process, to which several parties contributed, and by the definition of the strategy for comet characterisation, the orbital strategy for lander delivery, and the definition and validation of the operations timeline. The definition of the landing site selection process involved almost all components of the mission team; Rosetta has been the first, and so far only mission, that could not rely on data collected by previous missions for the landing site selection. This forced the teams to include an intensive observation campaign as a mandatory part of the process; several science teams actively contributed to this campaign thus making results from science observations part of the mandatory operational products. The time allocated to the comet characterisation phase was in the order of a few weeks and all the processes, tools, and interfaces required an extensive planning an validation. Being the descent of Philae purely ballistic, the main driver for the orbital strategy was the capability to accurately control the position and velocity of Rosetta at Philae's separation. The resulting operations timeline had to merge this need of frequent orbit determination and control with the complexity of the ground segment and the inherent risk of problems when doing critical activities in short times. This paper describes the contribution of the Mission Control Centre (MOC) at the European Space Operations Centre (ESOC) to this

  5. MIOSAT Mission Scenario and Design

    Science.gov (United States)

    Agostara, C.; Dionisio, C.; Sgroi, G.; di Salvo, A.

    2008-08-01

    MIOSAT ("Mssione Ottica su microSATellite") is a low-cost technological / scientific microsatellite mission for Earth Observation, funded by Italian Space Agency (ASI) and managed by a Group Agreement between Rheinmetall Italia - B.U. Spazio - Contraves as leader and Carlo Gavazzi Space as satellite manufacturer. Several others Italians Companies, SME and Universities are involved in the development team with crucial roles. MIOSAT is a microsatellite weighting around 120 kg and placed in a 525 km altitude sun-synchronuos circular LEO orbit. The microsatellite embarks three innovative optical payloads: Sagnac multi spectral radiometer (IFAC-CNR), Mach Zehender spectrometer (IMM-CNR), high resolution pancromatic camera (Selex Galileo). In addition three technological experiments will be tested in-flight. The first one is an heat pipe based on Marangoni effect with high efficiency. The second is a high accuracy Sun Sensor using COTS components and the last is a GNSS SW receiver that utilizes a Leon2 processor. Finally a new generation of 28% efficiency solar cells will be adopted for the power generation. The platform is highly agile and can tilt along and cross flight direction. The pointing accuracy is in the order of 0,1° for each axe. The pointing determination during images acquisition is definition, highlighting trade-offs for mission implementation. MIOSAT mission design has been constrained from challenging requirements in terms of satellite mass, mission lifetime, instrument performance, that have implied the utilization of satellite agility capability to improve instruments performance in terms of S/N and resolution. The instruments provide complementary measurements that can be combined in effective ways to exploit new applications in the fields of atmosphere composition analysis, Earth emissions, antropic phenomena, etc. The Mission is currently in phase B and the launch is planned for 2011.

  6. The Sun: Our Nearest Star

    Science.gov (United States)

    Adams, M. L.; Six, N. Frank (Technical Monitor)

    2002-01-01

    We have in our celestial backyard, a prime example of a variable star. The Sun, long thought to be "perfect" and unvarying, began to reveal its cycles in the early 1600s as Galileo Galilei and Christoph Scheiner used a telescope to study sunspots. For the past four hundred years, scientists have accumulated data, showing a magnetic cycle that repeats, on average, every eleven (or twenty-two) years. In addition, modern satellites have shown that the energy output at radio and x-ray wavelengths also varies with this cycle. This talk will showcase the Sun as a star and discuss how solar studies may be used to understand other stars.

  7. SunPy - Python for Solar Physics, Version 0.4

    Science.gov (United States)

    Christe, Steven; Mumford, Stuart; Perez-Suarez, David; Ireland, Jack; Shih, Albert Y.; Inglis, Andrew; Liedtke, Simon; Hewett, Russel

    2014-06-01

    We presents version 0.4 of SunPy, a community-developed Python package for solar physics. Python, a free, cross-platform, general-purpose, high-level programming language, has seen widespread adoption among the scientific community, resulting in the availability of a large number of software packages, from numerical computation NumPy, SciPy and machine learning (scikit-learn) to visualisation and plotting (matplotlib).SunPy is a data-analysis environment specialising in providing the software necessary to analyse solar and heliospheric datasets in Python. SunPy is open-source software (BSD licence) and has an open and transparent development workflow that anyone can contribute to. SunPy provides access to solar data through integration with the Virtual Solar Observatory (VSO), the Heliophysics Event Knowledgebase (HEK), and the HELiophysics Integrated Observatory (HELIO) webservices. It currently supports image data from major solar missions (e.g., SDO, SOHO, STEREO, and IRIS), time-series data from missions such as GOES, SDO/EVE, and PROBA2/LYRA, and radio spectra from e-Callisto and STEREO/SWAVES. We describe SunPy's functionality, provide examples of solar data analysis in SunPy, and show how Python-based solar data-analysis can leverage the many existing tools already available in Python. We discuss the future goals of the project and encourage interested users to become involved in the planning and development of SunPy.

  8. Kepler planet-detection mission

    DEFF Research Database (Denmark)

    Borucki...[], William J.; Koch, David; Buchhave, Lars C. Astrup

    2010-01-01

    The Kepler mission was designed to determine the frequency of Earth-sized planets in and near the habitable zone of Sun-like stars. The habitable zone is the region where planetary temperatures are suitable for water to exist on a planet’s surface. During the first 6 weeks of observations, Kepler...... is one of the lowest-density planets (~0.17 gram per cubic centimeter) yet detected. Kepler-5b, -6b, and -8b confirm the existence of planets with densities lower than those predicted for gas giant planets....

  9. Challenges for asteroseismic analysis of Sun-like stars

    CERN Document Server

    Chaplin, W J; Appourchaux, T; Elsworth, Y; New, R; Toutain, T

    2008-01-01

    Asteroseismology of Sun-like stars is undergoing rapid expansion with, for example, new data from the CoRoT mission and continuation of ground-based campaigns. There is also the exciting upcoming prospect of NASA's Kepler mission, which will allow the asteroseismic study of several hundred Sun-like targets, in some cases for periods lasting up to a few years. The seismic mode parameters are the input data needed for making inference on stars and their internal structures. In this paper we discuss the ease with which it will be possible to extract estimates of individual mode parameters, dependent on the mass, age, and visual brightness of the star. Our results are generally applicable; however, we look at mode detectability in the context of the upcoming Kepler observations. To inform our discussions we make predictions of various seismic parameters. To do this we use simple empirical scaling relations and detailed pulsation computations of the stochastic excitation and damping characteristics of the Sun-like...

  10. Energy Input Flux in the Global Quiet-Sun Corona

    Science.gov (United States)

    Mac Cormack, Cecilia; Vásquez, Alberto M.; López Fuentes, Marcelo; Nuevo, Federico A.; Landi, Enrico; Frazin, Richard A.

    2017-07-01

    We present first results of a novel technique that provides, for the first time, constraints on the energy input flux at the coronal base (r ˜ 1.025 R ⊙) of the quiet Sun at a global scale. By combining differential emission measure tomography of EUV images, with global models of the coronal magnetic field, we estimate the energy input flux at the coronal base that is required to maintain thermodynamically stable structures. The technique is described in detail and first applied to data provided by the Extreme Ultraviolet Imager instrument, on board the Solar TErrestrial RElations Observatory mission, and the Atmospheric Imaging Assembly instrument, on board the Solar Dynamics Observatory mission, for two solar rotations with different levels of activity. Our analysis indicates that the typical energy input flux at the coronal base of magnetic loops in the quiet Sun is in the range ˜0.5-2.0 × 105 (erg s-1 cm-2), depending on the structure size and level of activity. A large fraction of this energy input, or even its totality, could be accounted for by Alfvén waves, as shown by recent independent observational estimates derived from determinations of the non-thermal broadening of spectral lines in the coronal base of quiet-Sun regions. This new tomography product will be useful for the validation of coronal heating models in magnetohydrodinamic simulations of the global corona.

  11. Day the sun went out

    CERN Multimedia

    2007-01-01

    "A new british sci-fi movie envisages the death of the sun not in billions of years, but in decades. And, amazingly, the film's scientific adviser says this may not be so far from the truth..." (1/2 page)

  12. Effects of Early Sun Exposure

    Science.gov (United States)

    ... can be harmful. It can lead to:Skin changes. Some skin cells with melanin can form a clump. This creates freckles and moles. Over time, these can develop cancer.Early aging. Time spent in the sun makes your skin age faster than normal. Signs of this are wrinkled, tight, or leathery ...

  13. Tracking Planets around the Sun

    Science.gov (United States)

    Riddle, Bob

    2008-01-01

    In earlier columns, the celestial coordinate system of hour circles of right ascension and degrees of declination was introduced along with the use of an equatorial star chart (see SFA Star Charts in Resources). This system shows the planets' motion relative to the ecliptic, the apparent path the Sun follows during the year. An alternate system,…

  14. How Bright Is the Sun?

    Science.gov (United States)

    Berr, Stephen

    1991-01-01

    Presents a sequence of activities designed to allow eighth grade students to deal with one of the fundamental relationships that govern energy distribution. Activities guide students to measure light bulb brightness, discover the inverse square law, compare light bulb light to candle light, and measure sun brightness. (two references) (MCO)

  15. Tracking Planets around the Sun

    Science.gov (United States)

    Riddle, Bob

    2008-01-01

    In earlier columns, the celestial coordinate system of hour circles of right ascension and degrees of declination was introduced along with the use of an equatorial star chart (see SFA Star Charts in Resources). This system shows the planets' motion relative to the ecliptic, the apparent path the Sun follows during the year. An alternate system,…

  16. Modification of (DGEBA epoxy resin with maleated depolymerised natural rubber

    Directory of Open Access Journals (Sweden)

    2008-04-01

    Full Text Available In this work, diglycidyl ether of bisphenol A (DEGBA type epoxy resin has been modified with maleated depolymerised natural rubber (MDPR. MDPR was prepared by grafting maleic anhydride onto depolymerised natural rubber. MDPR has been characterized by Fourier transform infrared (FT-IR spectroscopy and nuclear magnetic resonance spectroscopy. MDPR was blended with epoxy resin at three different ratios (97/3, 98/2 and 99/1, by keeping the epoxy resin component as the major phase and maleated depolymerised natural rubber component as the minor phase. The reaction between the two blend components took place between the acid/anhydride group in the MDPR and the epoxide group of the epoxy resin. The proposed reaction schemes were supported by the FT-IR spectrum of the uncured Epoxy/MDPR blends. The neat epoxy resin and Epoxy/MDPR blends were cured by methylene dianiline (DDM at 100°C for three hours. Thermal, morphological and mechanical properties of the neat epoxy and the blends were investigated. Free volume studies of the cured, neat epoxy and Epoxy/MDPR blends were correlated with the morphological and mechanical properties of the same systems using Positron Annihilation Lifetime Studies.

  17. Contact allergy to epoxy resin: risk occupations and consequences.

    Science.gov (United States)

    Bangsgaard, Nannie; Thyssen, Jacob Pontoppidan; Menné, Torkil; Andersen, Klaus Ejner; Mortz, Charlotte G; Paulsen, Evy; Sommerlund, Mette; Veien, Niels Kren; Laurberg, Grete; Kaaber, Knud; Thormann, Jens; Andersen, Bo Lasthein; Danielsen, Anne; Avnstorp, Christian; Kristensen, Berit; Kristensen, Ove; Vissing, Susanne; Nielsen, Niels Henrik; Johansen, Jeanne Duus

    2012-08-01

    Epoxy resin monomers are strong skin sensitizers that are widely used in industrial sectors. In Denmark, the law stipulates that workers must undergo a course on safe handling of epoxy resins prior to occupational exposure, but the effectiveness of this initiative is largely unknown. To evaluate the prevalence of contact allergy to epoxy resin monomer (diglycidyl ether of bisphenol A; MW 340) among patients with suspected contact dermatitis and relate this to occupation and work-related consequences. The dataset comprised 20 808 consecutive dermatitis patients patch tested during 2005-2009. All patients with an epoxy resin-positive patch test were sent a questionnaire. A positive patch test reaction to epoxy resin was found in 275 patients (1.3%), with a higher proportion in men (1.9%) than in women (1.0%). The prevalence of sensitization to epoxy resin remained stable over the study period. Of the patients with an epoxy resin-positive patch test, 71% returned a questionnaire; 95 patients had worked with epoxy resin in the occupational setting, and, of these, one-third did not use protective gloves and only 50.5% (48) had participated in an educational programme. The 1% prevalence of epoxy resin contact allergy is equivalent to reports from other countries. The high occurrence of epoxy resin exposure at work, and the limited use of protective measures, indicate that reinforcement of the law is required. © 2012 John Wiley & Sons A/S.

  18. Mission design for LISA Pathfinder

    CERN Document Server

    Landgraf, M; Kemble, S

    2004-01-01

    Here we describe the mission design for SMART-2/LISA Pathfinder. The best trade-off between the requirements of a low-disturbance environment and communications distance is found to be a free-insertion Lissajous orbit around the first co-linear Lagrange point of the Sun-Earth system L1, 1.5x 10^6 km from Earth. In order to transfer SMART-2/LISA Pathfinder from a low Earth orbit, where it will be placed by a small launcher, the spacecraft carries out a number of apogee-raise manoeuvres, which ultimatively place it to a parabolic escape trajectory towards L1. The challenges of the design of a small mission are met, fulfilling the very demanding technology demonstration requirements without creating excessive requirements on the launch system or the ground segment.

  19. EPOXY RESINS TOUGHENED WITH CARBOXYL TERMINATED POLYETHERS

    Institute of Scientific and Technical Information of China (English)

    YU Yunchao; LI Yiming

    1983-01-01

    Carboxyl terminated polyethers, the adducts of hydroxyl terminated polytetrahydrofuran and maleic anhydride, were used as toughener for epoxy resins. The morphology of the toughened resins was investigated by means of turbidity measurement, dynamic mechanical testing and scanning electron microscope observation. It turned out that the molecular weight and the carboxyl content of the polyether and the cure conditions are important factors, which affect the particle size of the polyether-rich domains and, in turn, the mechanical properties of the cured resin. Carboxyl terminated polytetrahydrofurans have a low glass transition temperature, and in appropriate amount they do not affect the thermal resistance of the resin. These advantages make them preferable as toughener for epoxy resins.

  20. Cycloaliphatic epoxy resin coating for capillary electrophoresis.

    Science.gov (United States)

    Shah, Roopa S; Wang, Qinggang; Lee, Milton L

    2002-04-05

    Coating the interior surface of a fused-silica capillary with a polymeric material has long been used in capillary electrophoresis (CE) to reduce or eliminate electroosmotic flow and suppress adsorption. A cycloaliphatic epoxide-based resin was bonded to silane treated capillaries and crosslinked with a curing agent. The epoxy resin coating significantly reduced electroosmotic flow over a pH range of 3-10. This coating was sufficiently hydrophilic to suppress protein adsorption. The epoxy resin coated capillary was used to separate several acidic and basic proteins and peptides. Separation efficiencies greater than 400,000 theoretical plates were achieved. The relative standard deviations in migration times for proteins were methods.

  1. Investigations of toughening mechanisms of epoxy resins

    Science.gov (United States)

    Koenig, T.

    1986-01-01

    Composite material technology was applied to the solid rocket booster by the development of a carbon filament-epoxy resin case which yields a net increase of 4000 lbs. in payload in the shuttle. The question of reusability of the new composite tanks has not yet been answered and will depend on the toughness of the matrix resin. The present study was aimed at providing conditions whereby test specimens of the epoxy resin (EPON/85) and curing agents of systematically varied structures could be produced in a controlled manner. Three sets of conditions were found that might allow the isolation of the structural effects on toughness from the cure effects. The kinetic methods leading to the determination of these conditions are described.

  2. Permeability measurement and control for epoxy composites

    Science.gov (United States)

    Chang, Tsun-Hsu; Tsai, Cheng-Hung; Wong, Wei-Syuan; Chen, Yen-Ren; Chao, Hsien-Wen

    2017-08-01

    The coupling of the electric and magnetic fields leads to a strong interplay in materials' permittivity and permeability. Here, we proposed a specially designed cavity, called the mu cavity. The mu cavity, consisting of a mushroom structure inside a cylindrical resonator, is exclusively sensitive to permeability, but not to permittivity. It decouples materials' electromagnetic properties and allows an accurate measurement of the permeability. With the help of an epsilon cavity, these two cavities jointly determine the complex permeability and permittivity of the materials at microwave frequencies. Homemade epoxy-based composite materials were prepared and tested. Measurement and manipulation of the permeability and permittivity of the epoxy composites will be shown. The results will be compared with the effective medium theories.

  3. Epoxy thermoset networks derived from vegetable oils and their blends

    Science.gov (United States)

    Ryu, Chang; Ravalli, Matthew

    2015-03-01

    Epoxidized vegetable oils (EVOs), such as epoxidized soybean oil and linseed oils were prepared by the partial oxidation of the unsaturated double bonds in vegetable oils and used as monomers for preparing epoxy thermoset materials based on the cationic polymerization. These EVOs have been used to prepare epoxy thermosets of different network densities by cationic polymerization using onium salt catalyst. The crosslinked epoxy thermosets provide an ideal platform to study the structure-property-relationships of networked polymers. In particular, rheological studies on the epoxidized vegetable oil thermosets have been performed to measure the molecular weights between crosslinks (Mx) in the epoxy thermosets and to ultimately elucidate the role of functionality of epoxy groups in EVO on the mechanical and thermophysical properties of the epoxy thermoset materials. NSF DMR POLYMERS 1308617.

  4. Biobased Epoxy Nanocomposites Derived from Lignin-Based Monomers.

    Science.gov (United States)

    Zhao, Shou; Abu-Omar, Mahdi M

    2015-07-13

    Biobased epoxy nanocomposites were synthesized based on 2-methoxy-4-propylphenol (dihydroeugenol, DHE), a molecule that has been obtained from the lignin component of biomass. To increase the content of hydroxyl groups, DHE was o-demethylated using aqueous HBr to yield propylcatechol (DHEO), which was subsequently glycidylated to epoxy monomer. Optimal conditions in terms of yield and epoxy equivalent weight were found to be 60 °C with equal NaOH/phenolic hydroxyl molar ratio. The structural evolution from DHE to cured epoxy was followed by (1)H NMR and Fourier transform infrared spectroscopy. The nano-montmorillonite modified DHEO epoxy exhibited improved storage modulus and thermal stability as determined from dynamic mechanical analysis and thermogravimetric analysis. This study widens the synthesis routes of biobased epoxy thermosets from lignin-based molecules.

  5. Tanel Padar & The Sun veab õhukitarri

    Index Scriptorium Estoniae

    2008-01-01

    Õhukitarri Eesti meistrivõistlustest 19. apr. Tallinnas Rock Cafés (võistluste eestvedajaks on ansambel Tanel Padar & The Sun, kes samas esitleb oma esimest ingliskeelset albumit "Here Comes The Sun")

  6. Tanel Padar & The Sun veab õhukitarri

    Index Scriptorium Estoniae

    2008-01-01

    Õhukitarri Eesti meistrivõistlustest 19. apr. Tallinnas Rock Cafés (võistluste eestvedajaks on ansambel Tanel Padar & The Sun, kes samas esitleb oma esimest ingliskeelset albumit "Here Comes The Sun")

  7. Rubber-Modified Epoxies: Transitions and Morphology.

    Science.gov (United States)

    1980-09-01

    temperatures used for cure (i.e. Tso > Tcure). A low molecular weight liquid diglycidyl ether of bisphenol A ( DGEBA ) epoxy resin, Epon 828, Shell Chemical Co...the rubber damping peak always occurs at or below the Tg of unreacted CTBN even though CTBN is capped with DGEBA (see Ref. 5 which also shows that the...depression of RTg decreases with increasing amounts of rubber modifier in the formulations). DGEBA and CTBN must be incorporated in the domains since

  8. Epoxy-based carbon nanotubes reinforced composites

    CSIR Research Space (South Africa)

    Kesavan Pillai, Sreejarani

    2011-04-01

    Full Text Available blocks for 24 h at 60?C. Low and high magnification transmission electron microscopy (TEM) images of the thin slices cut from the composite showed that the thinner and longer nanotubes were preferentially oriented along the cutting direction, though... in Epon 828 epoxy resin matrix. The composites were cured with triethylene tetraamine hardener by gelling overnight at room temperature (RT) and curing at 100?C for 2 h. The micro-structural analysis of the composite using scanning electron microscopy...

  9. Solar sail mission design

    Energy Technology Data Exchange (ETDEWEB)

    Leipold, M.

    2000-02-01

    The main subject of this work is the design and detailed orbit transfer analysis of space flight missions with solar sails utilizing solar pressure for primary propulsion. Such a sailcraft requires ultra-light weight, gossamer-like deployable structures and materials in order to effectively utilize the transfer of momentum of solar photons. Different design concepts as well as technological elements for solar sails are considered, and an innovative design of a deployable sail structure including new methods for sail folding and unfolding is presented. The main focus of this report is on trajectory analysis, simulation and optimization of planetocentric as well as heliocentric low-thrust orbit transfers with solar sails. In a parametric analysis, geocentric escape spiral trajectories are simulated and corresponding flight times are determined. In interplanetary space, solar sail missions to all planets in our solar system as well as selected minor bodies are included in the analysis. Comparisons to mission concepts utilizing chemical propulsion as well as ion propulsion are included in order to assess whether solar sailing could possibly enhance or even enable this mission. The emphasis in the interplanetary mission analysis is on novel concepts: a unique method to realize a sun-synchronous Mercury orbiter, fast missions to the outer planets and the outer heliosphere applying a ''solar photonic assist'', rendezvous and sample return missions to asteroids and comets, as well as innovative concepts to reach unique vantage points for solar observation (''Solar Polar Orbiter'' and ''Solar Probe''). Finally, a propellant-less sailcraft attitude control concept using an external torque due to solar pressure is analyzed. Examples for sail navigation and control in circular Earth orbit applying a PD-control algorithm are shown, illustrating the maneuverability of a sailcraft. (orig.) [German] Gegenstand dieser

  10. Safe epoxy encapsulant for high voltage magnetics

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez, R.O.; Archer, W.E.

    1998-01-01

    This paper describes the use of Formula 456, an aliphatic amine cured epoxy for impregnating coils and high voltage transformers. Sandia has evaluated a number of MDA-free epoxy encapsulants which relied on either anhydride or other aromatic amine curing agents. The use of aliphatic amine curing agents was more recently evaluated and has resulted in the definition of Formula 456 resin. Methylene dianiline (MDA) has been used for more than 20 years as the curing agent for various epoxy formulations throughout the Department of Energy and much of industry. Sandia National Laboratories began the process of replacing MDA with other formulations because of regulations imposed by OSHA on the use of MDA. OSHA has regulated MDA because it is a suspect carcinogen. Typically the elimination of OSHA-regulated materials provides a rare opportunity to qualify new formulations in a range of demanding applications. It was important to take full advantage of that opportunity, although the associated materials qualification effort was costly. Small high voltage transformers are one of those demanding applications. The successful implementation of the new formulation for high reliability transformers will be described. The test results that demonstrate the parts are qualified for use in DOE weapon systems will be presented.

  11. Caddo Sun Accounts across Time and Place

    Science.gov (United States)

    Gerona, Carla

    2012-01-01

    Billy Day, a Tunica/Biloxi, recently described the significance of the sun for Caddoan people. Day quoted an "old Caddo relative" of his who said: "I used to go outside and hold my hands up and bless myself with the sun--'a'hat.' Well, I can't do that anymore because they say we are sun worshipers. We didn't worship the sun. We worshiped what was…

  12. Prediction of brittle fracture of epoxy-aluminum flanging

    Directory of Open Access Journals (Sweden)

    Korbel J.

    2010-07-01

    Full Text Available This paper presents a fracture mechanical approach for estimation of critical bending load of different types of aluminum-epoxy flanging and comparison with experimental measurements. For this purpose, several designs of the flanges were investigated. The flanges were glued to the epoxy bars and adhesive-epoxy interface was considered as a bi-material notch. Prediction of the failure is based on generalized stress intensity factor and generalized fracture toughness.

  13. Thermal properties of epoxy composites filled with boric acid

    OpenAIRE

    Visakh, P. M.; Nazarenko, Olga Bronislavovna; Amelkovich, Yuliya Alexandrovna; Melnikova, T. V.

    2015-01-01

    The thermal properties of epoxy composites filled with boric acid fine powder at different percentage were studied. Epoxy composites were prepared using epoxy resin ED-20, boric acid as flame-retardant filler, hexamethylenediamine as a curing agent. The prepared samples and starting materials were examined using methods of thermal analysis, scanning electron microscopy and infrared spectroscopy. It was found that the incorporation of boric acid fine powder enhances the thermal stability of ep...

  14. Multiscale Modeling of Graphite/CNT/Epoxy Hybrid Composites

    Science.gov (United States)

    2016-03-09

    AFRL-AFOSR-VA-TR-2016-0154 Multiscale Modeling of Graphite/CNT/Epoxy Hybrid Composites Gregory Odegard MICHIGAN TECHNOLOGICAL UNIVERSITY Final Report...SUBTITLE Multiscale Modeling of Graphite/CNT/Epoxy Hybrid Composites 5a. CONTRACT NUMBER 5b. GRANT NUMBER FA9550-13-1-0030 5c. PROGRAM ELEMENT NUMBER...DISTRIBUTION A: Distribution approved for public release. Final Report Multiscale Modeling of Graphite/CNT/Epoxy Hybrid Composites Grant FA9550-13-1-0030 PI

  15. Adding Effects of Reactive Oligomers for Epoxy Resin

    OpenAIRE

    山田, 英介; 稲垣, 慎二; 岡本, 弘

    1991-01-01

    Reactive oligomers with both functional end groups were prepared by the radical telomerization and the effect of oligomers added to bisphenol-A-glycidylehter type epoxy resin was investigated by measuring mechanical properties, adhesive properties and dynamic viscoelasticities. These oligomers were high viscous liquid except the one prepared from methyl methacrylate, therefore the blend of oligomers with epoxy resin is easy. Adding oligomers, the cured epoxy resins showed the lower glass-tran...

  16. Global Warming Blame the Sun

    CERN Document Server

    Calder, N

    1997-01-01

    Concern about climate change reaches a political peak at a UN conference in Kyoto, 1-10 December, but behind the scenes the science is in turmoil. A challenge to the hypothesis that greenhouse gases are responsible for global warming comes from the discovery that cosmic rays from the Galaxy are involved in making clouds (Svensmark and Friis-Christensen, 1997). During the 20th Century the wind from the Sun has grown stronger and the count of cosmic rays has diminished. With fewer clouds, the EarthÕs surface has warmed up. This surprising mechanism explains the link between the Sun and climate change that astronomers and geophysicists have suspected for 200 years.

  17. Selective Clay Placement Within a Silicate-Clay Epoxy Blend Nanocomposite

    Science.gov (United States)

    Miller, Sandi G (Inventor)

    2013-01-01

    A clay-epoxy nanocomposite may be prepared by dispersing a layered clay in an alkoxy epoxy, such as a polypropylene oxide based epoxide before combining the mixture with an aromatic epoxy to improve the nanocomposite's thermal and mechanical properties.

  18. Rate dependent response and failure of a ductile epoxy and carbon fiber reinforced epoxy composite

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Eric N [Los Alamos National Laboratory; Rae, Philip J [Los Alamos National Laboratory; Dattelbaum, Dana M [Los Alamos National Laboratory; Stahl, David B [Los Alamos National Laboratory

    2010-01-01

    An extensive characterization suite has been performed on the response and failure of a ductile epoxy 55A and uniaxial carbon fiber reinforced epoxy composite of IM7 fibers in 55A resin from the quasistatic to shock regime. The quasistatic and intermediate strain rate response, including elastic modulus, yield and failure have are characterized by quasistatic, SHPB, and DMA measurements as a function of fiber orientation and temperature. The high strain rate shock effect of fiber orientation in the composite and response of the pure resin are presented for plate impact experiments. It has previously been shown that at lower impact velocities the shock velocity is strongly dependent on fiber orientation but at higher impact velocity the in-plane and through thickness Hugoniots converge. The current results are compared with previous studies of the shock response of carbon fiber composites with more conventional brittle epoxy matrices. The spall response of the composite is measured and compared with quasistatic fracture toughness measurements.

  19. Total eclipses of the sun.

    Science.gov (United States)

    Zirker, J B

    1980-12-19

    Total eclipses of the sun offer research opportunities in a variety of sciences. Some of the advances in solar physics resulting from eclipse observations are discussed. Experiments at the total eclipse of 16 February 1980 in India are also described. These included a test of general relativity, studies in coronal physics, investigations of solar prominences, diameter measurements, a search for interplanetary dust, a study of the gravity waves in the earth's atmosphere, and experiments on the biological effects on animals and humans.

  20. Revisiting SU(N) integrals

    CERN Document Server

    Zuber, Jean-Bernard

    2016-01-01

    In this note, I revisit integrals over $\\SU(N)$ of the form $ \\int DU\\, U_{i_1j_1}\\cdots U_{i_pj_p}\\Ud_{k_1l_1}\\cdots \\Ud_{k_nl_n}$. While the case $p=n$ is well known, it seems that explicit expressions for $p=n+N$ had not appeared in the literature. Similarities and differences, in particular in the large $N$ limit, between the two cases are discussed

  1. LISA Pathfinder: mission and status

    Science.gov (United States)

    Antonucci, F.; Armano, M.; Audley, H.; Auger, G.; Benedetti, M.; Binetruy, P.; Boatella, C.; Bogenstahl, J.; Bortoluzzi, D.; Bosetti, P.; Caleno, M.; Cavalleri, A.; Cesa, M.; Chmeissani, M.; Ciani, G.; Conchillo, A.; Congedo, G.; Cristofolini, I.; Cruise, M.; Danzmann, K.; De Marchi, F.; Diaz-Aguilo, M.; Diepholz, I.; Dixon, G.; Dolesi, R.; Dunbar, N.; Fauste, J.; Ferraioli, L.; Fertin, D.; Fichter, W.; Fitzsimons, E.; Freschi, M.; García Marin, A.; García Marirrodriga, C.; Gerndt, R.; Gesa, L.; Gilbert, F.; Giardini, D.; Grimani, C.; Grynagier, A.; Guillaume, B.; Guzmán, F.; Harrison, I.; Heinzel, G.; Hewitson, M.; Hollington, D.; Hough, J.; Hoyland, D.; Hueller, M.; Huesler, J.; Jeannin, O.; Jennrich, O.; Jetzer, P.; Johlander, B.; Killow, C.; Llamas, X.; Lloro, I.; Lobo, A.; Maarschalkerweerd, R.; Madden, S.; Mance, D.; Mateos, I.; McNamara, P. W.; Mendes, J.; Mitchell, E.; Monsky, A.; Nicolini, D.; Nicolodi, D.; Nofrarias, M.; Pedersen, F.; Perreur-Lloyd, M.; Perreca, A.; Plagnol, E.; Prat, P.; Racca, G. D.; Rais, B.; Ramos-Castro, J.; Reiche, J.; Romera Perez, J. A.; Robertson, D.; Rozemeijer, H.; Sanjuan, J.; Schleicher, A.; Schulte, M.; Shaul, D.; Stagnaro, L.; Strandmoe, S.; Steier, F.; Sumner, T. J.; Taylor, A.; Texier, D.; Trenkel, C.; Tombolato, D.; Vitale, S.; Wanner, G.; Ward, H.; Waschke, S.; Wass, P.; Weber, W. J.; Zweifel, P.

    2011-05-01

    LISA Pathfinder, the second of the European Space Agency's Small Missions for Advanced Research in Technology (SMART), is a dedicated technology demonstrator for the joint ESA/NASA Laser Interferometer Space Antenna (LISA) mission. The technologies required for LISA are many and extremely challenging. This coupled with the fact that some flight hardware cannot be fully tested on ground due to Earth-induced noise led to the implementation of the LISA Pathfinder mission to test the critical LISA technologies in a flight environment. LISA Pathfinder essentially mimics one arm of the LISA constellation by shrinking the 5 million kilometre armlength down to a few tens of centimetres, giving up the sensitivity to gravitational waves, but keeping the measurement technology: the distance between the two test masses is measured using a laser interferometric technique similar to one aspect of the LISA interferometry system. The scientific objective of the LISA Pathfinder mission consists then of the first in-flight test of low frequency gravitational wave detection metrology. LISA Pathfinder is due to be launched in 2013 on-board a dedicated small launch vehicle (VEGA). After a series of apogee raising manoeuvres using an expendable propulsion module, LISA Pathfinder will enter a transfer orbit towards the first Sun-Earth Lagrange point (L1). After separation from the propulsion module, the LPF spacecraft will be stabilized using the micro-Newton thrusters, entering a 500 000 km by 800 000 km Lissajous orbit around L1. Science results will be available approximately 2 months after launch.

  2. Coherent States with SU(N) Charges

    CERN Document Server

    Mathur, M; Mathur, Manu; Paul, Samir K.

    2003-01-01

    We define coherent states carrying SU(N) charges by exploiting generalized Schwinger boson representation of SU(N) Lie algebra. These coherent states are defined on $2 (2^{N - 1} - 1)$ complex planes. They satisfy continuity property and provide resolution of identity. We also exploit this technique to construct the corresponding non-linear SU(N) coherent states.

  3. The Sun Rises on the Solar Sector

    OpenAIRE

    Ahmad, Reyaz A.

    2009-01-01

    Energy from the sun is abundant and free. Solar energy is in essence electromagnetic radiation emitted from the sun. Earth's climate, hydrologic systems, and ecosystems all derive from the sun. Other forms of renewable power such as wind, wave, biomass, and hydro are an indirect function of solar radiation.

  4. The Sun A User's Manual

    CERN Document Server

    Vita-Finzi, Claudio

    2008-01-01

    The Sun is an account of the many ways in which our nearest star affects our planet, how its influence has changed over the last few centuries and millennia, and the extent to which we can predict its future impact. The Sun's rays foster the formation of Vitamin D by our bodies, but it can also promote skin cancer, cataracts, and mutations in our DNA. Besides providing the warmth and light essential to most animal and plant life, solar energy contributes substantially to global warming. Although the charged particles of the solar wind shield us from harmful cosmic rays, solar storms may damage artificial satellites and cripple communication systems and computer networks. The Sun is the ideal renewable energy source, but its exploitation is still bedevilled by the problems of storage and distribution. Our nearest star, in short, is a complex machine which needs to be treated with caution, and this book will equip every reader with the knowledge that is required to understand the benefits and dangers it can bri...

  5. The faint young Sun problem

    CERN Document Server

    Feulner, Georg

    2012-01-01

    For more than four decades, scientists have been trying to find an answer to one of the most fundamental questions in paleoclimatology, the `faint young Sun problem'. For the early Earth, models of stellar evolution predict a solar energy input to the climate system which is about 25% lower than today. This would result in a completely frozen world over the first two billion years in the history of our planet, if all other parameters controlling Earth's climate had been the same. Yet there is ample evidence for the presence of liquid surface water and even life in the Archean (3.8 to 2.5 billion years before present), so some effect (or effects) must have been compensating for the faint young Sun. A wide range of possible solutions have been suggested and explored during the last four decades, with most studies focusing on higher concentrations of atmospheric greenhouse gases like carbon dioxide, methane or ammonia. All of these solutions present considerable difficulties, however, so the faint young Sun prob...

  6. Cobalt Ions Improve the Strength of Epoxy Resins

    Science.gov (United States)

    Stoakley, D. M.; St. Clair, A. K.

    1986-01-01

    Technique developed for improving mechanical strength of epoxy resins by adding cobalt ions in form of tris(acetylacetonato)cobalt (III) complex. Solid cast disks prepared from cobalt ion-containing epoxy resins tested for flexural strength and stiffness. Incorporation of cobalt ions into epoxies increased flexural strength of resins by 10 to 95 percent. Suitable resins for this technique include any liquid or solid TGMDA resins. Improved epoxy formulation proves useful as composite matrix resin, adhesive, or casting resin for applications on commercial and advanced aircraft.

  7. THE POLYMERIZATION OF ROOM TEMPERATURE CURING EPOXY RESINS

    Science.gov (United States)

    EPOXY RESINS , *PLASTICS, *POLYMERIZATION, AGING (PHYSIOLOGY), CHEMICAL BONDS, ELECTRICAL PROPERTIES, EMBEDDING SUBSTANCES, MONITORS, POLYMERS, RESISTANCE (ELECTRICAL), STORAGE, STRUCTURES, TEMPERATURE, TEST METHODS, VOLUME

  8. Persistent photosensitivity after allergic contact dermatitis to epoxy resin.

    Science.gov (United States)

    Kwok, Tiffany; Rosen, Cheryl F; Storrs, Frances J; Lobel, Edmund; DeKoven, Joel G

    2013-01-01

    Persistent photosensitivity after allergic contact dermatitis (ACD) to epoxy resin has rarely been described. The aim of this study was to create awareness that ACD to epoxy may be a trigger for persistent photosensitivity. We present a series of 5 patients who developed ACD to epoxy resin and later a photodistributed eczematous eruption when exposed to sunlight, with a documented decrease in minimal erythema dose to UVA and UVB. The age of patients ranged from 34 to 71 years, and there were 3 men and 2 women. Each patient had occupational exposure to epoxy. Symptoms of epoxy ACD preceded photosensitivity by 5 months to 12 years in 3 cases and occurred simultaneously in 2 cases. Patch testing to epoxy resin was positive in all patients. Phototesting revealed a decreased minimal erythema dose to UVA and UVB in each of the 3 patients who were phototested. Photopatch testing was positive for epoxy resin in 1 of the 2 patients tested. All patients remained photosensitive for at least 2 years after diagnosis, with only 1 case of photosensitivity resolving with extended avoidance of epoxy. There is an association between ACD to epoxy resin and development of persistent photosensitivity. Possible mechanisms to explain the relationship between the 2 phenomena are discussed.

  9. Effect of the hardener to epoxy monomer ratio on the water absorption behavior of the DGEBA/TETA epoxy system

    Directory of Open Access Journals (Sweden)

    Ayrton Alef Castanheira Pereira

    2016-02-01

    Full Text Available Abstract The water absorption behavior of the DGEBA/TETA epoxy system was evaluated as a function of the epoxy monomer to amine hardener ratio. Weight gain versus immersion time curves were obtained and the experimental points were fitted using Fickian and Non-Fickian diffusion models. The results obtained showed that for all epoxy monomer to hardener ratios analyzed water diffusion followed non-Fickian behavior. It was possible to correlate the water absorption behavior to the macromolecular structure developed when the epoxy/ hardener ratio was varied. All epoxy/hardener ratios present a two-phase macromolecular structure, composed of regions with high crosslink density and regions with lower crosslinking. Epoxy rich systems have a more open macromolecular structure with a lower fraction of the dense phase than the amine rich systems, which present a more compact two-phase structure.

  10. Sun Savvy Students: Free Teaching Resources from EPA's SunWise Program

    Science.gov (United States)

    Hall-Jordan, Luke

    2008-01-01

    With summer in full swing and the sun is naturally on our minds, what better time to take advantage of a host of free materials provided by the U.S. Environmental Protection Agency's Sun Wise program. Sun Wise aims to teach students and teachers about the stratospheric ozone layer, ultraviolet (UV) radiation, and how to be safe while in the Sun.…

  11. Swarm: Recent Progress in Analysis of the Sun Induced Magnetic Disturbance

    DEFF Research Database (Denmark)

    Tøffner-Clausen, Lars; Lesur, Vincent; Brauer, Peter

    The ESA Earth Observation Magnetic Mission Swarm carries high precision vector and scalar magnetometers. Careful analyses have revealed s smaller, Sun driven magnetic disturbance of the vector magnetometer. This disturbance have been imperically mapped and corrected since mid 2015. This work...

  12. Swarm: Recent Progress in Analysis of the Sun Induced Magnetic Disturbance

    DEFF Research Database (Denmark)

    Tøffner-Clausen, Lars; Lesur, Vincent; Brauer, Peter

    The ESA Earth Observation Magnetic Mission Swarm carries high precision vector and scalar magnetometers. Careful analyses have revealed s smaller, Sun driven magnetic disturbance of the vector magnetometer. This disturbance have been imperically mapped and corrected since mid 2015. This work...

  13. SOHO reveals violent action on the quiet Sun

    Science.gov (United States)

    1996-05-01

    and rearranges itself, sunspots multiply and huge explosions become commonplace. "Everyone is impressed by SOHO's performance," says Roger Bonnet, the European Space Agency's Director of Science. "By the end of the mission we shall know the Sun far better than we do now. Then we shall understand the stars better too, because the Sun is the star we see with most clarity. And we shall be able to comment with much more confidence on important but puzzling aspects of solar behaviour that affect our lives on the Earth, whether in short-lived magnetic storms or long-lasting changes of climate."

  14. Exoplanet Searches by Future Deep Space Missions

    Directory of Open Access Journals (Sweden)

    Maccone C.

    2011-02-01

    Full Text Available The search for exoplanets could benefit from gravitational lensing if we could get to 550 AU from the Sun and beyond. This is because the gravitational lens of the Sun would highly intensify there any weak electromagnetic wave reaching the solar system from distant planets in the Galaxy (see Maccone 2009. The gravitational lens of the Sun, however, has a drawback: the solar Corona. Electrons in the Corona make electromagnetic waves diverge and this pushes the focus out to distances higher than 550 AU. Jupiter is the second larger mass in the solar system after the Sun, but in this focal game not only the mass matters: rather, what really matters is the ratio between the radius of the body squared and the mass of the body. In this regard, Jupiter qualifies as the second best choice for a space mission, requiring the spacecraft to reach 6,077 AU. In this paper, we study the benefit of exoplanet searches by deep space missions.

  15. Atomistic Modeling of Thermal Conductivity of Epoxy Nanotube Composites

    Science.gov (United States)

    Fasanella, Nicholas A.; Sundararaghavan, Veera

    2016-05-01

    The Green-Kubo method was used to investigate the thermal conductivity as a function of temperature for epoxy/single wall carbon nanotube (SWNT) nanocomposites. An epoxy network of DGEBA-DDS was built using the `dendrimer' growth approach, and conductivity was computed by taking into account long-range Coulombic forces via a k-space approach. Thermal conductivity was calculated in the direction perpendicular to, and along the SWNT axis for functionalized and pristine SWNT/epoxy nanocomposites. Inefficient phonon transport at the ends of nanotubes is an important factor in the thermal conductivity of the nanocomposites, and for this reason discontinuous nanotubes were modeled in addition to long nanotubes. The thermal conductivity of the long, pristine SWNT/epoxy system is equivalent to that of an isolated SWNT along its axis, but there was a 27% reduction perpendicular to the nanotube axis. The functionalized, long SWNT/epoxy system had a very large increase in thermal conductivity along the nanotube axis (~700%), as well as the directions perpendicular to the nanotube (64%). The discontinuous nanotubes displayed an increased thermal conductivity along the SWNT axis compared to neat epoxy (103-115% for the pristine SWNT/epoxy, and 91-103% for functionalized SWNT/epoxy system). The functionalized system also showed a 42% improvement perpendicular to the nanotube, while the pristine SWNT/epoxy system had no improvement over epoxy. The thermal conductivity tensor is averaged over all possible orientations to see the effects of randomly orientated nanotubes, and allow for experimental comparison. Excellent agreement is seen for the discontinuous, pristine SWNT/epoxy nanocomposite. These simulations demonstrate there exists a threshold of the SWNT length where the best improvement for a composite system with randomly oriented nanotubes would transition from pristine SWNTs to functionalized SWNTs.

  16. Thermal Expansion and Swelling of Cured Epoxy Resin Used in Graphite/Epoxy Composite

    Science.gov (United States)

    Adamson, M. J.

    1979-01-01

    The thermal expansion and swelling of resin material as influenced by variations in temperature during moisture absorption is discussed. Comparison measurements using composites constructed of graphite fibers and each of two epoxy resin matrices are included. Polymer theory relative to these findings is discussed and modifications are proposed.

  17. Epoxy-resin adhesive and method for bonding using such an epoxy resin adhesive

    NARCIS (Netherlands)

    Bhowmik, S.; Poulis, J.A.; Benedictus, R.

    2008-01-01

    The invention relates to an epoxy resin adhesive comprising a dotation of nano-substances, wherein the nano- substances are selected from the group comprising carbon-fibre nanotubes, carbon nano-fibres, silicate nano powders, and wherein the nano-substances are dispersed in the adhesive with a weigh

  18. Epoxy-resin adhesive and method for bonding using such an epoxy resin adhesive

    NARCIS (Netherlands)

    Bhowmik, S.; Poulis, J.A.; Benedictus, R.

    2008-01-01

    The invention relates to an epoxy resin adhesive comprising a dotation of nano-substances, wherein the nano- substances are selected from the group comprising carbon-fibre nanotubes, carbon nano-fibres, silicate nano powders, and wherein the nano-substances are dispersed in the adhesive with a

  19. Micro technology based sun sensor

    DEFF Research Database (Denmark)

    Hales, Jan Harry; Pedersen, Martin; Fléron, René

    2003-01-01

    There is increasing interest among universities in the scientific and educational possibilities of picosatellites base on the CubeSat 5 concept. Due to sever mass and dimension constraints place on this type of satellites, new approaches and ideas regarding different systems arises to accommodate...... DTUsat sun sensors are needed along with a magnetometer to obtain unambiguous attitude determination for the ACDS and the payloads - an electrodynamic tether and a camera. The accuracy needed was not obtainable by employing conventional attitude sensors. Hence a linear slit sensor was designed...

  20. Suspended microstructures of epoxy based photoresists fabricated with UV photolithography

    DEFF Research Database (Denmark)

    Hemanth, Suhith; Anhøj, Thomas Aarøe; Caviglia, Claudia

    2017-01-01

    In this work we present an easy, fast, reliable and low cost microfabrication technique for fabricating suspended microstructures of epoxy based photoresistswith UV photolithography. Two different fabrication processes with epoxy based resins (SU-8 and mr-DWL) using UV exposures at wavelengths of...

  1. Microstructural Design & Optimization of Highly Filled Epoxy Based Composites

    Science.gov (United States)

    2009-11-01

    particle concentration and decreasing the particle size were found to increase the stress at 4% strain [5]. A study of aluminum filled epoxy ( DGEBA ...to increase the strength corresponding to 4% plastic strain [5]. A study of aluminum filled epoxy ( DGEBA /MTHPA) composites has found that a small

  2. The training in epoxy-impregnated superconducting coils

    Energy Technology Data Exchange (ETDEWEB)

    Fujita, H.; Bobrov, E.S.; Iwasa, Y.; Takaghi, T.; Tsukamoto, O.

    1985-03-01

    The authors have investigated the training of epoxy-impregnated superconducting coils. It has been observed that the boundary conditions at the coil ends have a crucial effect on shear-stress-induced epoxy cracks in the winding and consequently on the coil training. The results were quantified using acoustic emission data.

  3. Positron Annihilation in a Rubber Modified Epoxy Resin

    DEFF Research Database (Denmark)

    Mogensen, O. E.; Jacobsen, F. M.; Pethrick, R. A.

    1979-01-01

    Positron annihilation data is reported on a rubber-modified epoxy resin. Studies of the temperature dependence of the o-positronium lifetime indicated the existence of three distinct regions; the associated transition temperatures by comparison with dilatometric data can be ascribed respectively...... to be glass transition of the epoxy phase and to that of a mixed acrylonitrile—epoxy—butadiene interfacial region....

  4. The Durability of Epoxy Resin Coating

    Institute of Scientific and Technical Information of China (English)

    ZHAO Fujun; BA Hengjing; GAO Xiaojian

    2008-01-01

    The durability of epoxy resin coating was studied under environments with relative humidity(RH) of 98%-100%, at 55 ℃ for 900 h, at 65℃ for 700 h and at 75 ℃ for 400 h, respectively. Peel strength test, dynamical mechanical thermal analysis (DMTA), infrared spectroscopy (IR) and energy dispersive X-ray spectroscopy (EDX) were employed for measurements. Peel strength indicated the development of adhesive property of the coating, DMTA indicated the development of physical property, IR revealed the development of chemical structure, and EDX showed surface element change of the coating. All these results show a good time-temperature equivalence characteristic between humidity aging time and temperature.

  5. Nonlinear time dependent behaviour of epoxy resins

    Science.gov (United States)

    Marotzke, C.; Feldmann, T.

    2016-07-01

    The nonlinear behaviour of epoxy resins is studied on standard tensile tests. A strain field measurement system is applied (Aramis) in order to monitor local strains. The residual strain is measured by recovering the specimens for up to 68 hours after unloading. The time span the specimen is exposed to load has a large influence on the creeping process and the residual strain after recovering. This is studied by comparison of instantaneous unloading with keeping the specimen under permanent load for thirty minutes. It is shown that moderate differences in the initial strain can lead to large differences in the creep behaviour as well as in the residual strain.

  6. RHEOLOGICAL BEHAVIOR OF EPOXY RESIN WATERBORNE DISPERSIONS

    Institute of Scientific and Technical Information of China (English)

    Zhen-zhong Yang; Yuan-ze Xu; De-lu Zhao

    2001-01-01

    The waterborne dispersions of epoxy resin were prepared by the phase inversion emulsification technique.Rheological behavior and its relationship with the structural change of the systems were studied. It was shown that the concentrated dispersions were highly viscoelastic and pseudoplastic, which was attributed to the formation of a physical network among the waterborne particles via hydrogen bond. The dilute dispersions were Newtonian fluids. The discrete clusters composed of small waterborne particles were found in diluted dispersions. With increasing solid content, there existed a structural transition via percolation through a cluster-cluster aggregation mode to form the physical network, which was qualitatively evidenced by the TEM morphologies.``

  7. Dielectric properties of nanosilica filled epoxy nanocomposites

    Indian Academy of Sciences (India)

    M G VEENA; N M RENUKAPPA; KUNIGAL N SHIVAKUMAR; S SEETHARAMU

    2016-04-01

    This paper presents the development of epoxy-silica nanocomposites and characterized for dielectric properties. The effect of nanosilica loading (0–20 wt%), frequency, temperature and sea water aging on these properties was studied. Transmission electron microscopy (TEM) analysis of the samples showed an excellent dispersion. However, at higher silica loading TEM showed inter-contactity of the particles. The dielectric constant (υ') increased with silica loading and reached an optimum at about 10 wt%. The υ' of the nanocomposites showed linear decrease with frequency whereas AC conductivity (σac) increases. The σac and υ' increased marginally with temperature and sea water aging.

  8. Epoxy Pipelining Composition and Method of Manufacture.

    Science.gov (United States)

    1994-12-14

    resin such as DGEBA (the diglycidyl ether of bisphenol A; see infra page 38) 16 and/or DGEBF (the diglycidyl ether of bisphenol F; see infra page 38...acid and 1,2 DCH, 20 about 22.4 mole % of the benzyl alcohol (i.e. the exemplary reactive diluent), and about 21 6.26 mole % of the DGEBA wherein x = 0...of the part A epoxy resin 5 ( DGEBA : Epon° 828, and/or Araldite XU Bis F GY° 281) containing optional 6 pigments such as Titanium Oxide (TiO 2 R-960

  9. Thermomechanical stability of graphite/epoxy composites.

    Science.gov (United States)

    Goggin, W R

    1974-02-01

    Results are reported on an investigation to evaluate the usefulness of selected graphite/epoxy composite structures for applications requiring precision tolerancing and dimensional stability. Thornel 75S/ELRB 4617 and Modmor 1/ELRB 4617 laminate composites in a six-ply design were tested, as well as a honeycomb design having two Thornel/ELRB faceplates bonded to an aluminum honeycomb core. Measurements were made of thermal expansion coefficient and its directional variations, microyielding and microcreep behavior, thermal and temporal stabilities. Data, discussion of results, and recommendations for applicable areas are given for the specific material and design types tested.

  10. Toughening of epoxy resins by epoxidized soybean oil

    Energy Technology Data Exchange (ETDEWEB)

    Frischinger, I.; Dirlikov, S. [Eastern Michigan Univ., Ypsilanti, MI (United States)

    1993-12-31

    Homogeneous mixtures of a liquid rubber based on prepolymers of epoxidized soybean oil with amines, diglycidyl ether of bisphenol A epoxy resins, and commercial diamines form, under certain conditions, two-phase thermosetting materials that consist of a rigid epoxy matrix and randomly distributed small rubbery soybean particles (0.1-5 {mu}m). These two-phase thermosets have improved toughness, similar to that of other rubber-modified epoxies, low water absorption, and low sodium content. In comparison to the unmodified thermosets, the two-phase thermosets exhibit slightly lower glass-transition temperatures and Young`s moduli, but their dielectric properties do not change. The epoxidized soybean oil is available at a price below that of commercial epoxy resins and appears very attractive for epoxy toughening on an industrial scale. 15 refs., 17 figs., 6 tabs.

  11. Physical aging of linear and network epoxy resins

    Science.gov (United States)

    Kong, E. S.-W.; Wilkes, G. L.; Mcgrath, J. E.; Banthia, A. K.; Mohajer, Y.; Tant, M. R.

    1981-01-01

    Network and linear epoxy resins principally based on the diglycidyl ether of bisphenol-A and its oligomers are prepared and studied using diamine and anhydride crosslinking agents. Rubber modified epoxies and a carbon fiber reinforced composite are also investigated. All materials display time-dependent changes when stored at temperatures below the glass transition temperature after quenching (sub-T/g/ annealing). Solvent sorption experiments initiated after different sub-T(g) annealing times demonstrate that the rate of solvent uptake can be indirectly related to the free volume of the epoxy resins. Residual thermal stresses and water are found to have little effect on the physical aging process, which affects the sub-T(g) properties of uniaxial carbon fiber reinforced epoxy material. Finally, the importance of the recovery phenomenon which affects the durability of epoxy glasses is considered.

  12. Insights into Epoxy Network Nanostructural Heterogeneity Using AFM-IR.

    Science.gov (United States)

    Morsch, Suzanne; Liu, Yanwen; Lyon, Stuart B; Gibbon, Simon R

    2016-01-13

    The first direct observation of a chemically heterogeneous nanostructure within an epoxy resin is reported. Epoxy resins comprise the matrix component of many high performance composites, coatings and adhesives, yet the molecular network structure that underpins the performance of these industrially essential materials is not well understood. Internal nodular morphologies have repeatedly been reported for epoxy resins analyzed using SEM or AFM, yet the origin of these features remains a contentious subject, and epoxies are still commonly assumed to be chemically homogeneous. Uniquely, in this contribution we use the recently developed AFM-IR technique to eliminate previous differences in interpretation, and establish that nodule features correspond to heterogeneous network connectivity within an epoxy phenolic formulation.

  13. Biobased Epoxy Resins from Deconstructed Native Softwood Lignin.

    Science.gov (United States)

    van de Pas, Daniel J; Torr, Kirk M

    2017-08-14

    The synthesis of novel epoxy resins from lignin hydrogenolysis products is reported. Native lignin in pine wood was depolymerized by mild hydrogenolysis to give an oil product that was reacted with epichlorohydrin to give epoxy prepolymers. These were blended with bisphenol A diglycidyl ether or glycerol diglycidyl ether and cured with diethylenetriamine or isophorone diamine. The key novelty of this work lies in using the inherent properties of the native lignin in preparing new biobased epoxy resins. The lignin-derived epoxy prepolymers could be used to replace 25-75% of the bisphenol A diglycidyl ether equivalent, leading to increases of up to 52% in the flexural modulus and up to 38% in the flexural strength. Improvements in the flexural strength were attributed to the oligomeric products present in the lignin hydrogenolysis oil. These results indicate lignin hydrogenolysis products have potential as sustainable biobased polyols in the synthesis of high performance epoxy resins.

  14. Method for epoxy foam production using a liquid anhydride

    Science.gov (United States)

    Celina, Mathias [Albuquerque, NM

    2012-06-05

    An epoxy resin mixture with at least one epoxy resin of between approximately 50 wt % and 100 wt %, an anhydride cure agent of between approximately 0 wt % and approximately 50 wt %, a tert-butoxycarbonyl anhydride foaming agent of between proximately 0.1-20 wt %, a surfactant and an imidazole or similar catalyst of less than approximately 2 wt %, where the resin mixture is formed from at least one epoxy resin with a 1-10 wt % tert-butoxycarbonyl anhydride compound and an imidazole catalyst at a temperature sufficient to keep the resin in a suitable viscosity range, the resin mixture reacting to form a foaming resin which in the presence of an epoxy curative can then be cured at a temperature greater than 50.degree. C. to form an epoxy foam.

  15. Impact Resistance of Short Fibre/Particle Reinforced Epoxy

    Science.gov (United States)

    Chang, L.; Zhang, Z.; Breidt, C.

    2004-01-01

    The influence of temperature on the fracture behaviour of epoxy-based composites was studied using an instrumented Charpy impact approach. A series of epoxy reinforced with short carbon fibres (SCF) and additionally filled with various amounts of PTFE and graphite particles was considered in this study. Unnotched specimens were tested at -196°C, 20°C, and 70°C, respectively. It was found that, for specimens with the same matrix content, a proper hybridisation of composites was possible to achieve a better impact performance compared to single-filler/epoxy. For example, 10 vol.%PTFE+10 vol.%SCF/epoxy exhibited a higher impact resistance than that of 20 vol.%SCF/epoxy at all measured temperatures. Failure mechanisms at different temperatures were discussed with SEM fractography.

  16. Designing of epoxy resin systems for cryogenic use

    Science.gov (United States)

    Ueki, T.; Nishijima, S.; Izumi, Y.

    2005-02-01

    The mechanical and thermal properties of several types of epoxy systems were designed based on the chemical structure, network structure and morphology aiming at cryogenic application. In this research di-epoxies or multifunctional epoxies were cured by several kinds of hardeners such as anhydride, amine or phenol and were blended with polycarbonate, carboxyl-terminated butadiene acrylonitrile copolymer or phenoxy. The mechanical properties and thermal properties of these cured epoxies were measured at room and liquid nitrogen temperature. It was found that the two-dimensional network structured linear polymer shows high performance even at cryogenic temperature. It was concluded that the controls of the structures are very important to optimize epoxy systems for cryogenic application.

  17. Seismology of the Wounded Sun

    CERN Document Server

    Cally, Paul S

    2013-01-01

    Active regions are open wounds in the Sun's surface. Seismic oscillations from the interior pass through them into the atmosphere, changing their nature in the process to fast and slow magneto-acoustic waves. The fast waves then partially reflect and partially mode convert to upgoing and downgoing Alfv\\'en waves. The reflected fast and downgoing Alfv\\'en waves then re-enter the interior through the active regions that spawned them, infecting the surface seismology with signatures of the atmosphere. Using numerical simulations of waves in uniform magnetic fields, we calculate the upward acoustic and Alfv\\'enic losses in the atmosphere as functions of field inclination and wave orientation as well as the Time-Distance `travel time' perturbations, and show that they are related. Travel time perturbations relative to quiet Sun can exceed 40 seconds in 1 kG magnetic field. It is concluded that active region seismology is indeed significantly infected by waves leaving and re-entering the interior through magnetic w...

  18. The Sun's New Exotic Neighbour

    Science.gov (United States)

    2006-03-01

    Using ESO's Very Large Telescope in Chile, an international team of researchers [1] discovered a brown dwarf belonging to the 24th closest stellar system to the Sun. Brown dwarfs are intermediate objects that are neither stars nor planets. This object is the third closest brown dwarf to the Earth yet discovered, and one of the coolest, having a temperature of about 750 degrees Celsius. It orbits a very small star at about 4.5 times the mean distance between the Earth and the Sun. Its mass is estimated to be somewhere between 9 and 65 times the mass of Jupiter. At a time when astronomers are peering into the most distant Universe, looking at objects as far as 13 billion light-years away, one may think that our close neighbourhood would be very well known. Not so. Astronomers still find new star-like objects in our immediate vicinity. Using ESO's VLT, they just discovered a brown dwarf companion to the red star SCR 1845-6357, the 36th closest star to the Sun. ESO PR Photo 11/06 ESO PR Photo 11a/06 New Brown Dwarf in the Solar Neighbourhood (Artist's Impression) "This newly found brown dwarf is a valuable object because its distance is well known, allowing us to determine with precision its intrinsic brightness", said team member Markus Kasper (ESO). "Moreover, from its orbital motion, we should be able in a few years to estimate its mass. These properties are vital for understanding the nature of brown dwarfs." To discover this brown dwarf, the team used the high-contrast adaptive optics NACO Simultaneous Differential Imager (SDI [2]) on ESO's Very Large Telescope, an instrument specifically developed to search for extrasolar planets. The SDI camera enhances the ability of the VLT and its adaptive optics system to detect faint companions that would normally be lost in the glare of the primary star. In particular, the SDI camera provides additional, often very useful spectral information which can be used to determine a rough temperature for the object without follow

  19. Sun-earth connection education through modern views of ancient

    Science.gov (United States)

    Thieman, J. R.

    The NASA Sun-Earth Connection Education Forum (SECEF) has the responsibility of using the latest science results from the study of solar physics, space physics, and aeronomy to inspire students in the classroom and to inform the public in general. SECEF works with NASA's Sun-Earth Connection spaceflight missions to accomplish this goal. Each year the missions and SECEF combine to promote their science through a major event designed to attract the attention of all. In late 2004 and 2005 the event will be the study of solar observatories created by ancient peoples and a comparison of their knowledge and culture to present understanding. Two solar observatory sites will be featured, Chaco Canyon in the U.S. and Chichen Itza in Mexico. There are many other places throughout the world that could also be featured as solar observatories and some of these may be described on the SECEF web site or used in future occurrences. Special emphasis is placed on events associated with the solstice and equinox dates. It is hoped that there will be happenings around the world on these days and SECEF will work with many museums, science centers, and other groups to help make this happen. Plans for the 2005 Ancient Observatories event and possible future events on the same subject will be described.

  20. Here comes the sun...; Here comes the sun...

    Energy Technology Data Exchange (ETDEWEB)

    Best, Robert [Centro de Investigacion en Energia (CIE) de la UNAM, Temixco, Morelos (Mexico)

    2010-07-01

    It sounds a bit strange that you can use solar energy to maintain or refrigerate products or spaces below the ambient temperature, because we know that something that makes the sun is heating; but yes indeed, the sun can produce cold, and in addition without polluting, and without consuming conventional energy. In this document are mentioned the various research projects on solar cooling that have been made in the Energy Research Center at the Universidad Nacional Autonoma de Mexico such as the thermo-chemical intermittent refrigerator, the geothermal cooling demonstration system in Mexicali, B.C., the GAX system for air conditioning, the ice producer intermittent solar refrigerator, the continuous solar refrigerator, the refrigeration by ejection-compression. It also mentions the functioning of heat pumps and the process of solar drying applications in agricultural products. [Spanish] Suena un poco extrano que se pueda utilizar la energia solar para mantener o refrigerar productos o espacios por debajo de la temperatura ambiente, ya que sabemos que algo que hace el sol es calentar; pero si, el sol puede producir frio, y ademas sin contaminar y sin consumir energia convencional. En este documento se mencionan las diferentes investigaciones sobre refrigeracion solar que se han realizado en el Centro de Investigacion en Energia de la Universidad Nacional Autonoma de Mexico como el refrigerador termoquimico intermitente, el sistema demostrativo de refrigeracion geotermico en Mexicali, B.C., el sistema GAX para aire acondicionado, el refrigerador solar intermitente productor de hielo, el refrigerador continuo solar, la refrigeracion por eyecto-compresion. Tambien se menciona el funcionamiento de las bombas de calor y el proceso de secado solar de aplicacion en productos agropecuarios.

  1. A Tale of 2 Missions (And Hopefully 2 Different Landings)

    Energy Technology Data Exchange (ETDEWEB)

    Wiens, Roger C. [Los Alamos National Laboratory

    2012-07-19

    This talk, to be given at the LANL IGPP Annual Review dinner in Santa Fe, NM on July 17, 2012, highlights two important NASA missions LANL played a key role in: The Genesis mission was the first to return to Earth from beyond the Moon, bearing solar particles to help understand the composition of the Sun; and Curiosity, a 1-ton Mars rover launched to the red planet in 2011 with a suite of instruments from LANL called ChemCam.

  2. Comparison of structural health assessment capabilities in epoxy – carbon black and epoxy – carbon nanotube nanocomposites

    Directory of Open Access Journals (Sweden)

    F. Inam

    2014-01-01

    Full Text Available A novel method for comparing structural health of different types of brittle epoxy nanocomposites filled with carbon nanostructured fillers is presented. Epoxy – 0.2 vol% carbon black (CB and epoxy – 0.2 vol% carbon nanotube (CNT nanocomposite bars were prepared by calendering and thermal curing. Nanocomposite bars were subjected to Vickers diamond indentation to produce sub-surface damage. Electrical conductivities were analysed by 4-point method to estimate the structural damage caused by indentation. For comprehensive comparison, fracture toughness and percolation threshold were analysed as well. Because of the systematically induced indentation damage, a sharp decrease of 89% was observed in the electrical conductivity of epoxy – CNT nanocomposite as compared to 25% in the electrical conductivity of epoxy – CB nanocomposite. CNTs impart superior damage sensing capability in brittle nanocomposite structures, in comparison to CB, due to their high aspect ratio (fibrous nature and high electrical conductivity.

  3. Epoxy Sol-Gel Hybrid Thermosets

    Directory of Open Access Journals (Sweden)

    Angels Serra

    2016-02-01

    Full Text Available Sol-gel methodologies are advantageous in the preparation of hybrid materials in front of the conventional addition of nanoparticles, because of the fine dispersion of the inorganic phase that can be reached in epoxy matrices. In addition, the use of organoalkoxysilanes as coupling agents allows covalent linkage between organic and inorganic phases, which is the key point in the improvement of mechanical properties. The sol-gel process involves hydrolysis and condensation reactions under mild conditions, starting from hydrolysable metal alkoxides, generally alkoxy silanes. Using the sol-gel procedure, the viscosity of the formulation is maintained, which is an important issue in coating applications, whereas the transparency of the polymer matrix is also maintained. However, only the proper combination of the chemistries and functionalities of both organic and inorganic structures leads to thermosets with the desired characteristics. The adequate preparation of hybrid epoxy thermosets enables their improvement in characteristics such as mechanical properties (modulus, hardness, scratch resistance, thermal and flame resistance, corrosion and antimicrobial protection, and even optical performance among others.

  4. Multiwall carbon nanotubes reinforced epoxy nanocomposites

    Science.gov (United States)

    Chen, Wei

    The emergence of carbon nanotubes (CNTs) has led to myriad possibilities for structural polymer composites with superior specific modulus, strength, and toughness. While the research activities in carbon nanotube reinforced polymer composites (NRPs) have made enormous progress towards fabricating next-generation advanced structural materials with added thermal, optical, and electrical advantages, questions concerning the filler dispersion, interface, and CNT alignment in these composites remain partially addressed. In this dissertation, the key technical challenges related to the synthesis, processing, and reinforcing mechanics governing the effective mechanical properties of NRPs were introduced and reviewed in the first two chapters. Subsequently, issues on the dispersion, interface control, hierarchical structure, and multi-functionality of NRPs were addressed based on functionalized multi-walled carbon nanotube reinforced DGEBA epoxy systems (NREs). In chapter 3, NREs with enhanced flexural properties were discussed in the context of improved dispersion and in-situ formation of covalent bonds at the interface. In chapter 4, NREs with controlled interface and tailored thermomechanical properties were demonstrated through the judicious choice of surface functionality and resin chemistry. In chapter 5, processing-condition-induced CNT organization in hierarchical epoxy nanocomposites was analyzed. In Chapter 6, possibilities were explored for multi-functional NREs for underwater acoustic structural applications. Finally, the findings of this dissertation were concluded and future research was proposed for ordered carbon nanotube array reinforced nanocomposites in the last chapter. Four journal publications resulted from this work are listed in Appendix.

  5. Solar Probe Plus: Mission design challenges and trades

    Science.gov (United States)

    Guo, Yanping

    2010-11-01

    NASA plans to launch the first mission to the Sun, named Solar Probe Plus, as early as 2015, after a comprehensive feasibility study that significantly changed the original Solar Probe mission concept. The original Solar Probe mission concept, based on a Jupiter gravity assist trajectory, was no longer feasible under the new guidelines given to the mission. A complete redesign of the mission was required, which called for developing alternative trajectories that excluded a flyby of Jupiter. Without the very powerful gravity assist from Jupiter it was extremely difficult to get to the Sun, so designing a trajectory to reach the Sun that is technically feasible under the new mission guidelines became a key enabler to this highly challenging mission. Mission design requirements and challenges unique to this mission are reviewed and discussed, including various mission scenarios and six different trajectory designs utilizing various planetary gravity assists that were considered. The V 5GA trajectory design using five Venus gravity assists achieves a perihelion of 11.8 solar radii ( RS) in 3.3 years without any deep space maneuver (DSM). The V 7GA trajectory design reaches a perihelion of 9.5 RS using seven Venus gravity assists in 6.39 years without any DSM. With nine Venus gravity assists, the V 9GA trajectory design shows a solar orbit at inclination as high as 37.9° from the ecliptic plane can be achieved with the time of flight of 5.8 years. Using combined Earth and Venus gravity assists, as close as 9 RS from the Sun can be achieved in less than 10 years of flight time at moderate launch C3. Ultimately the V 7GA trajectory was chosen as the new baseline mission trajectory. Its design allowing for science investigation right after launch and continuing for nearly 7 years is unprecedented for interplanetary missions. The redesigned Solar Probe Plus mission is not only feasible under the new guidelines but also significantly outperforms the original mission concept

  6. TRIGONOMETRIC SU(N) GAUDIN MODEL

    Institute of Scientific and Technical Information of China (English)

    曹俊鹏; 侯伯宇; 岳瑞宏

    2001-01-01

    In this paper, we obtain the eigenstates and the eigenvalues of the Hamiltonians of the trigonometric SU(N) Gaudin model based on the quasi-classical limit of the trigonometric SU(N) chain with the periodic boundary condition.By using the quantum inverse scattering method, we also obtain the eigenvalues of the generating function of the trigonometric SU(N) Gaudin model.

  7. The summer sun shone round me

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The summer sun shone round me, The folded valley lay In a stream of sun and odour, That sultry summer day. The tall trees stood in the sunlight As still as still could be, But the deep grass sighed and rustled And bowed and beckoned me. The deep grass moved and whispered And bowed and brushed my face. It whis pered in the sunshine: The winter comes apdce.”The summer sun shone round me

  8. Sun awareness in Maltese secondary school students.

    Science.gov (United States)

    Aquilina, S; Gauci, A Amato; Ellul, M; Scerri, L

    2004-11-01

    Studies indicate that reducing exposure to ultraviolet light during childhood and adolescence decreases the risk of skin cancer. From a young age, children need to be educated about the sun's harmful effects on the skin and how best to protect themselves. To help in the design of school-based interventions to raise sun awareness, a school survey was carried out to identify students' stereotypes and misconceptions. A total of 965 students attending Maltese secondary schools in forms 1, 2 and 3 were surveyed in May 2002, using a structured questionnaire designed to examine students' sun-related attitudes and knowledge. A high level of sun awareness among students was demonstrated, with high scores on knowledge of the effects of the sun on the skin, knowledge of skin cancer and knowledge of sun protection. Girls were clearly more knowledgeable than boys. However, of all the students surveyed, 55% thought that a suntan made them look better and 70% thought that their friends would desire a tan. These views were commoner among the older students. Skin type and hair or eye colour had no bearing on attitudes towards tanning or sun-related knowledge. The commonest misconceptions were that 'the sun is bad for your skin only when you get sunburnt' and that 'you cannot get too much sun on a cloudy day'. Deliberate suntanning was more frequently reported by girls than by boys and by students in the higher forms. Attitude change lags behind knowledge. Future school sun awareness interventions need to take into account gender and age differences in students' attitudes and perspectives. They should aim at motivating attitude change and preventive behaviour through consistent and repeated sun-education messages that are supported by a sun-conscious school environment.

  9. Sun Jingxia Devotes Herself to Nursing Work

    Institute of Scientific and Technical Information of China (English)

    1995-01-01

    "I really didn’t expect that at my advanced age, I would be awarded the highest honor in international nursing circles," said Mme. Sun Jingxia, 81, who had just returned from Beijing where she received the Nightingale Medal. Wearing a light yellow suit, with a collar bordered in red, Sun is inhigh spirits, reminding people of the beauty of the setting sun. It is clear that Sun Jingxia has deep feelings as she looks at the medal which shows a relief of Florence Nightingale’s head. She spoke in her usual soft voice but with some excitement, "President Jiang

  10. SmartSat Experiment for the L5 Mission

    Science.gov (United States)

    Nagatsuma, T.; Akioka, M.; Ohtaka, K.; Miyake, W.; Goka, T.; Matsumoto, H.; Koshiishi, H.

    2004-12-01

    We have planned the L5 mission for space weather research and operational forecasting experiment. In this mission, a spacecraft will be deployed at the L5 point of the Sun - Earth system for remote sensing of the Sun and the interplanetary space, and for in-situ measurements of the solar wind plasma and high energy particles. For this mission, NICT and JAXA develop wide field imager for tracking CME propagation from the Sun to the Earth and advanced high-energy particle sensor for monitoring of solar particle events, respectively. Before proceeding the L5 mission, we are planning orbital demonstration in GTO using a platform of small satellite, called "SmartSat". The SmartSat program is a collaborative program of government agencies (NICT and JAXA), and a private company (Mitsubishi Heavy Industry) in Japan. The wide field coronal imager (WCI) and space environment data acquisition experiment (SEDA) will be tested by this program as the space weather experiment, since both of the instruments will be principal components of the L5 mission. The SmartSat is planned to be launched by 2007, about 1 year after the launch of STEREO spacecrafts. Therefore, we are expecting the coordinated observation with STEREO mission. In this paper, we will report an overview of the space weather experiment in SmartSat program.

  11. ULYSSES comes full circle, before revisiting the Sun's poles

    Science.gov (United States)

    1998-04-01

    From its unique perspective, Ulysses has provided scientists with the very first all-round map of the heliosphere, the huge bubble in space filled by the Sun's wind. The Earth swims deep inside the heliosphere, and gusts and shocks in the solar wind can harm satellites, power supplies and ommunications. They may also affect our planet's weather. A better grasp of the solar weather in the heliosphere is therefore one of the major aims of ESA's science programme. In a project of international cooperation between ESA and NASA, Ulysses was launched towards Jupiter in October 1990 by the US space shuttle Discovery. Arriving in February 1992, Ulysses stole energy from the giant planet in a slingshot manoeuvre and was propelled back towards the Sun in an elongated orbit almost at right angles to the ecliptic plane, where the Earth and other planets circle the Sun. "This month Ulysses returns to the point in space where its out-of-ecliptic journey began, but Jupiter isn't there," explains Richard Marsden, ESA's project scientist for Ulysses. "Following its own inexorable path around the Sun, Jupiter is far away on the opposite side of the Solar System. So Ulysses' course will not be changed a second time. The spacecraft is now in effect a man-made comet, forever bound into a 6-year polar orbit around the Sun." Ulysses now starts its second orbit. It will travel over the poles of the Sun in 2000-2001 just as the count of dark sunspots is expected to reach a maximum. With its operational life extended for the Ulysses Solar Maximum Mission, the spacecraft will find the heliosphere much stormier than during its first orbit. Discoveries so far Like its mythical namesake, Ulysses has already had an eventful voyage of discovery. Its unique trajectory has provided the scientific teams with a new perspective, from far out in space and especially in the previously unknown regions of the heliosphere over the Sun's poles. Passing within 9.8 degrees of the polar axis, the highly

  12. Progress toward Making Epoxy/Carbon-Nanotube Composites

    Science.gov (United States)

    Tiano, Thomas; Roylance, Margaret; Gassner, John; Kyle, William

    2008-01-01

    A modicum of progress has been made in an effort to exploit single-walled carbon nanotubes as fibers in epoxy-matrix/fiber composite materials. Two main obstacles to such use of carbon nanotubes are the following: (1) bare nanotubes are not soluble in epoxy resins and so they tend to agglomerate instead of becoming dispersed as desired; and (2) because of lack of affinity between nanotubes and epoxy matrices, there is insufficient transfer of mechanical loads between the nanotubes and the matrices. Part of the effort reported here was oriented toward (1) functionalization of single-walled carbon nanotubes with methyl methacrylate (MMA) to increase their dispersability in epoxy resins and increase transfer of mechanical loads and (2) ultrasonic dispersion of the functionalized nanotubes in tetrahydrofuran, which was used as an auxiliary solvent to aid in dispersing the functionalized nanotubes into a epoxy resin. In another part of this effort, poly(styrene sulfonic acid) was used as the dispersant and water as the auxiliary solvent. In one experiment, the strength of composite of epoxy with MMA-functionalized-nanotubes was found to be 29 percent greater than that of a similar composite of epoxy with the same proportion of untreated nanotubes.

  13. All Sky Survey Mission Observing Scenario Strategy

    CERN Document Server

    Spangelo, Sara C; Unwin, Stephen C; Bock, Jamie J

    2014-01-01

    This paper develops a general observing strategy for missions performing all-sky surveys, where a single spacecraft maps the celestial sphere subject to realistic constraints. The strategy is flexible such that targeted observations and variable coverage requirements can be achieved. This paper focuses on missions operating in Low Earth Orbit, where the thermal and stray-light constraints due to the Sun, Earth, and Moon result in interacting and dynamic constraints. The approach is applicable to broader mission classes, such as those that operate in different orbits or that survey the Earth. First, the instrument and spacecraft configuration is optimized to enable visibility of the targeted observations throughout the year. Second, a constraint-based high-level strategy is presented for scheduling throughout the year subject to a simplified subset of the constraints. Third, a heuristic-based scheduling algorithm is developed to assign the all-sky observations over short planning horizons. The constraint-based...

  14. Mathematical SETI Statistics, Signal Processing, Space Missions

    CERN Document Server

    Maccone, Claudio

    2012-01-01

    This book introduces the Statistical Drake Equation where, from a simple product of seven positive numbers, the Drake Equation is turned into the product of seven positive random variables. The mathematical consequences of this transformation are demonstrated and it is proven that the new random variable N for the number of communicating civilizations in the Galaxy must follow the lognormal probability distribution when the number of factors in the Drake equation is allowed to increase at will. Mathematical SETI also studies the proposed FOCAL (Fast Outgoing Cyclopean Astronomical Lens) space mission to the nearest Sun Focal Sphere at 550 AU and describes its consequences for future interstellar precursor missions and truly interstellar missions. In addition the author shows how SETI signal processing may be dramatically improved by use of the Karhunen-Loève Transform (KLT) rather than Fast Fourier Transform (FFT). Finally, he describes the efforts made to persuade the United Nations to make the central part...

  15. Development and Characterization of Novel Interpenetrating Network (IPN Foams from Epoxy Ester and Aliphatic Epoxy Resin

    Directory of Open Access Journals (Sweden)

    Kanuprasad Patel

    2009-01-01

    Full Text Available Diglycidyl ether of bisphenol-A (DGEBA was reacted with acrylate monomer at variable molar ratios. The reaction between glycerine and epichlorohydrine form glycidyl ether of polyol aliphatic epoxy resin. The resultant resins were characterized duly. Both the resins were mixed at different ratios with constant high shear stirring. The obtained mixture and suitable additives were heated at 150oC for one and half hour. The so called Interpenetrating Network (IPN transformed into foams. The performance of foams was evaluated by testing for compression in both parallel and perpendicular to rise direction. The tests were carried out at room temperature and at the elevated temperature. The compression properties showed a decreasing trend for increasing amounts of glycerine resin. The density and thermal properties of epoxy foams were also evaluated. The relation between the composition, density and properties of the foam was analyzed.

  16. Invariant Manifolds, Lagrangian Trajectories and Space Mission Design

    Science.gov (United States)

    Belló, Miguel; Gómez, Gerard; Masdemont, Josep J.

    The last 30 years have produced an explosion in the capabilities of designing and managing libration point missions. The starting point was the ground-breaking mission of the third International Sun-Earth Explorer spacecraft (ISEE-3). The ISEE-3 was launched August 12, 1978 to pursue studies of the Earth-Sun interactions, in a first step of what now is known as Space Weather. After a direct transfer of the ISEE-3 to the vicinity of the Sun-Earth Lagrange point, it was inserted into a nearly-periodic halo orbit, in order to monitor the solar wind about 1 h before it reached the Earth's magneto-sphere as well as the ISEE-1 and 2 spacecraft (which where in an elliptical orbit around the Earth).

  17. Sample Return Missions Where Contamination Issues are Critical: Genesis Mission Approach

    Science.gov (United States)

    Allton, Judith H.; Stansbery E. K.

    2011-01-01

    The Genesis Mission, sought the challenging analytical goals of accurately and precisely measuring the elemental and isotopic composition of the Sun to levels useful for planetary science, requiring sensitivities of ppm to ppt in the outer 100 nm of collector materials. Analytical capabilities were further challenged when the hard landing in 2004 broke open the canister containing the super-clean collectors. Genesis illustrates that returned samples allow flexibility and creativity to recover from setbacks.

  18. Effect of Glass Reinforced Epoxy (GRE) pipe filled with Geopolymer Materials for Piping Application: Compression Properties

    OpenAIRE

    2016-01-01

    The aim of this paper is to achieve the highest compressive strength of glass reinforced epoxy pipe with the geopolymer filler content of weight percentage that were used in glass reinforced epoxy pipe. The samples were prepared by using the filament winding method. The effect of weight percentage of geopolymer materials in epoxy hardener was studied under mechanical testing, which is using the compression test. A series of glass reinforced epoxy pipe and glass reinforced epoxy pipe filled wi...

  19. Deep Space Networking Experiments on the EPOXI Spacecraft

    Science.gov (United States)

    Jones, Ross M.

    2011-01-01

    NASA's Space Communications & Navigation Program within the Space Operations Directorate is operating a program to develop and deploy Disruption Tolerant Networking [DTN] technology for a wide variety of mission types by the end of 2011. DTN is an enabling element of the Interplanetary Internet where terrestrial networking protocols are generally unsuitable because they rely on timely and continuous end-to-end delivery of data and acknowledgments. In fall of 2008 and 2009 and 2011 the Jet Propulsion Laboratory installed and tested essential elements of DTN technology on the Deep Impact spacecraft. These experiments, called Deep Impact Network Experiment (DINET 1) were performed in close cooperation with the EPOXI project which has responsibility for the spacecraft. The DINET 1 software was installed on the backup software partition on the backup flight computer for DINET 1. For DINET 1, the spacecraft was at a distance of about 15 million miles (24 million kilometers) from Earth. During DINET 1 300 images were transmitted from the JPL nodes to the spacecraft. Then, they were automatically forwarded from the spacecraft back to the JPL nodes, exercising DTN's bundle origination, transmission, acquisition, dynamic route computation, congestion control, prioritization, custody transfer, and automatic retransmission procedures, both on the spacecraft and on the ground, over a period of 27 days. The first DINET 1 experiment successfully validated many of the essential elements of the DTN protocols. DINET 2 demonstrated: 1) additional DTN functionality, 2) automated certain tasks which were manually implemented in DINET 1 and 3) installed the ION SW on nodes outside of JPL. DINET 3 plans to: 1) upgrade the LTP convergence-layer adapter to conform to the international LTP CL specification, 2) add convergence-layer "stewardship" procedures and 3) add the BSP security elements [PIB & PCB]. This paper describes the planning and execution of the flight experiment and the

  20. Deep Space Networking Experiments on the EPOXI Spacecraft

    Science.gov (United States)

    Jones, Ross M.

    2011-01-01

    NASA's Space Communications & Navigation Program within the Space Operations Directorate is operating a program to develop and deploy Disruption Tolerant Networking [DTN] technology for a wide variety of mission types by the end of 2011. DTN is an enabling element of the Interplanetary Internet where terrestrial networking protocols are generally unsuitable because they rely on timely and continuous end-to-end delivery of data and acknowledgments. In fall of 2008 and 2009 and 2011 the Jet Propulsion Laboratory installed and tested essential elements of DTN technology on the Deep Impact spacecraft. These experiments, called Deep Impact Network Experiment (DINET 1) were performed in close cooperation with the EPOXI project which has responsibility for the spacecraft. The DINET 1 software was installed on the backup software partition on the backup flight computer for DINET 1. For DINET 1, the spacecraft was at a distance of about 15 million miles (24 million kilometers) from Earth. During DINET 1 300 images were transmitted from the JPL nodes to the spacecraft. Then, they were automatically forwarded from the spacecraft back to the JPL nodes, exercising DTN's bundle origination, transmission, acquisition, dynamic route computation, congestion control, prioritization, custody transfer, and automatic retransmission procedures, both on the spacecraft and on the ground, over a period of 27 days. The first DINET 1 experiment successfully validated many of the essential elements of the DTN protocols. DINET 2 demonstrated: 1) additional DTN functionality, 2) automated certain tasks which were manually implemented in DINET 1 and 3) installed the ION SW on nodes outside of JPL. DINET 3 plans to: 1) upgrade the LTP convergence-layer adapter to conform to the international LTP CL specification, 2) add convergence-layer "stewardship" procedures and 3) add the BSP security elements [PIB & PCB]. This paper describes the planning and execution of the flight experiment and the

  1. Thermomechanical Behavior of High Performance Epoxy/Organoclay Nanocomposites

    Directory of Open Access Journals (Sweden)

    Artur Soares Cavalcanti Leal

    2014-01-01

    Full Text Available Nanocomposites of epoxy resin containing bentonite clay were fabricated to evaluate the thermomechanical behavior during heating. The epoxy resin system studied was prepared using bifunctional diglycidyl ether of bisphenol A (DGEBA, crosslinking agent diaminodiphenylsulfone (DDS, and diethylenetriamine (DETA. The purified bentonite organoclay (APOC was used in all experiments. The formation of nanocomposite was confirmed by X-ray diffraction analysis. Specimens of the fabricated nanocomposites were characterized by dynamic mechanical analysis (DMA. According to the DMA results a significant increase in glass transition temperature and storage modulus was evidenced when 1 phr of clay is added to epoxy resin.

  2. Realtime 3D stress measurement in curing epoxy packaging

    DEFF Research Database (Denmark)

    Richter, Jacob; Hyldgård, A.; Birkelund, Karen;

    2007-01-01

    This paper presents a novel method to characterize stress in microsystem packaging. A circular p-type piezoresistor is implemented on a (001) silicon chip. We use the circular stress sensor to determine the packaging induced stress in a polystyrene tube filled with epoxy. The epoxy curing process...... is monitored by stress measurements. From the stress measurements we conclude that the epoxy cures in 8 hours at room temperature. We find the difference in in-plane normal stresses to be sigmaxx-sigmayy=6.7 MPa and (sigmaxx+sigmayy-0.4sigmazz)=232 MPa....

  3. Wear behaviour of epoxy resin filled with hard powders

    Science.gov (United States)

    Formisano, A.; Boccarusso, L.; Minutolo, F. Capece; Carrino, L.; Durante, M.; Langella, A.

    2016-10-01

    The development of high performance materials based on epoxy resin finds a growing number of applications in which high wear resistance is required. One major drawback in many of these applications is the relatively poor wear resistance of the epoxy resin. Therefore, in order to investigate on the possibility of increasing wear resistance of thermoset polymers filled with hard powders, sliding tests are carried out by means of a pin on disc apparatus. In particular, composite resins, constituted by an epoxy resin filled with different contents and sizes of Silicon Carbide powder, are analyzed; the wear resistance, in terms of volume loss, is measured for different abrasive counterfaces and loads.

  4. Hansen solubility parameters for a carbon fiber/epoxy composite

    DEFF Research Database (Denmark)

    Launay, Helene; Hansen, Charles M.; Almdal, Kristoffer

    2007-01-01

    In this study, the physical affinity between an epoxy matrix and oxidized, unsized carbon fibers has been evaluated using Hansen solubility (cohesion) parameters (HSP). A strong physical compatibility has been shown, since their respective HSP are close. The use of a glassy carbon substrate...... as a model for unsized carbon fiber has been demonstrated as appropriate for the study of interactions between the materials in composite carbon fiber-epoxy systems. The HSP of glassy carbon are similar to those of carbon fibers and epoxy matrix. (C) 2007 Elsevier Ltd. All rights reserved....

  5. LISA Pathfinder: mission and status

    Energy Technology Data Exchange (ETDEWEB)

    Antonucci, F; Cavalleri, A; Congedo, G [Dipartimento di Fisica, Universita di Trento and INFN, Gruppo Collegato di Trento, 38050 Povo, Trento (Italy); Armano, M [European Space Astronomy Centre, European Space Agency, Villanueva de la Canada, 28692 Madrid (Spain); Audley, H; Bogenstahl, J; Danzmann, K [Albert-Einstein-Institut, Max-Planck-Institut fuer Gravitationsphysik und Universitaet Hannover, 30167 Hannover (Germany); Auger, G; Binetruy, P [APC UMR7164, Universite Paris Diderot, Paris (France); Benedetti, M [Dipartimento di Ingegneria dei Materiali e Tecnologie Industriali, Universita di Trento and INFN, Gruppo Collegato di Trento, Mesiano, Trento (Italy); Boatella, C [CNES, DCT/AQ/EC, 18 Avenue Edouard Belin, 31401 Toulouse, Cedex 9 (France); Bortoluzzi, D; Bosetti, P; Cristofolini, I [Dipartimento di Ingegneria Meccanica e Strutturale, Universita di Trento and INFN, Gruppo Collegato di Trento, Mesiano, Trento (Italy); Caleno, M; Cesa, M [European Space Technology Centre, European Space Agency, Keplerlaan 1, 2200 AG Noordwijk (Netherlands); Chmeissani, M [IFAE, Universitat Autonoma de Barcelona, E-08193 Bellaterra, Barcelona (Spain); Ciani, G [Department of Physics, University of Florida, Gainesville, FL 32611-8440 (United States); Conchillo, A [ICE-CSIC/IEEC, Facultat de Ciencies, E-08193 Bellaterra, Barcelona (Spain); Cruise, M, E-mail: Paul.McNamara@esa.int [Department of Physics and Astronomy, University of Birmingham, Birmingham (United Kingdom)

    2011-05-07

    LISA Pathfinder, the second of the European Space Agency's Small Missions for Advanced Research in Technology (SMART), is a dedicated technology demonstrator for the joint ESA/NASA Laser Interferometer Space Antenna (LISA) mission. The technologies required for LISA are many and extremely challenging. This coupled with the fact that some flight hardware cannot be fully tested on ground due to Earth-induced noise led to the implementation of the LISA Pathfinder mission to test the critical LISA technologies in a flight environment. LISA Pathfinder essentially mimics one arm of the LISA constellation by shrinking the 5 million kilometre armlength down to a few tens of centimetres, giving up the sensitivity to gravitational waves, but keeping the measurement technology: the distance between the two test masses is measured using a laser interferometric technique similar to one aspect of the LISA interferometry system. The scientific objective of the LISA Pathfinder mission consists then of the first in-flight test of low frequency gravitational wave detection metrology. LISA Pathfinder is due to be launched in 2013 on-board a dedicated small launch vehicle (VEGA). After a series of apogee raising manoeuvres using an expendable propulsion module, LISA Pathfinder will enter a transfer orbit towards the first Sun-Earth Lagrange point (L1). After separation from the propulsion module, the LPF spacecraft will be stabilized using the micro-Newton thrusters, entering a 500 000 km by 800 000 km Lissajous orbit around L1. Science results will be available approximately 2 months after launch.

  6. The Suess-Urey mission (return of solar matter to Earth).

    Science.gov (United States)

    Rapp, D; Naderi, F; Neugebauer, M; Sevilla, D; Sweetnam, D; Burnett, D; Wiens, R; Smith, N; Clark, B; McComas, D; Stansbery, E

    1996-01-01

    The Suess-Urey (S-U) mission has been proposed as a NASA Discovery mission to return samples of matter from the Sun to the Earth for isotopic and chemical analyses in terrestrial laboratories to provide a major improvement in our knowledge of the average chemical and isotopic composition of the solar system. The S-U spacecraft and sample return capsule will be placed in a halo orbit around the L1 Sun-Earth libration point for two years to collect solar wind ions which implant into large passive collectors made of ultra-pure materials. Constant Spacecraft-Sun-Earth geometries enable simple spin stabilized attitude control, simple passive thermal control, and a fixed medium gain antenna. Low data requirements and the safety of a Sun-pointed spinner, result in extremely low mission operations costs.

  7. Regina vs Hubbs: Determining the Sun's Position

    CERN Document Server

    Samra, Raminder Singh

    2012-01-01

    Here I determined the Sun's position as an expert witness for crown counsel. From my calculations I found the Sun's location in the sky was such that it could not impede the driver's vision, as a result it could not have been the reason for the accused to be involved in a motor vehicle accident.

  8. Modelling UV sky for future UV missions

    Science.gov (United States)

    Sreejith, A. G.; Safanova, M.; Mohan, R.; Murthy, Jayant

    Software simulators are now widely used in all areas of science, especially in application to astronomical missions: from instrument design to mission planning, and to data interpretation. We present a simulator to model the diffuse ultraviolet sky, where the different contributors are separately calculated and added together to produce a sky image of the size specified by the instrument requirements. Each of the contributors to the background, instrumental dark current, airglow, zodiacal light and diffuse galactic light, is dependent on various factors. Airglow is dependent on the time of day, zodiacal light on the time of year, angle from the Sun and from the ecliptic, and diffuse UV emission depends on the look direction. To provide a full description of any line of sight, we have also added stars. The diffuse UV background light can dominate in many areas of the sky and severely impact space telescopes viewing directions due to over brightness. The simulator, available as a downloadable package and as a simple web-based tool, can be applied to separate missions and instruments. For demonstration, we present the example used for two UV missions: the UVIT instrument on the Indian ASTROSAT mission to be launched in the next year and a prospective wide-field mission to search for transients in the UV.

  9. Contactless optoelectronic technique for monitoring epoxy cure.

    Science.gov (United States)

    Cusano, A; Buonocore, V; Breglio, G; Calabrò, A; Giordano, M; Cutolo, A; Nicolais, L

    2000-03-01

    We describe a novel noninvasive optical technique to monitor the refractive-index variation in an epoxy-based resin that is due to the polymerization process. This kind of resin is widely used in polymer matrix composites. It is well known that the process of fabricating a thermoset-based composite involves mass and heat transfer coupled with irreversible chemical reactions that induce physical changes. To improve the quality and the reliability of these materials, monitoring the cure and optimization of the manufacturing process are of key importance. We discuss the basic operating principles of an optical system based on angle deflection measurements and present typical cure-monitoring results obtained from optical characterization. The method provides a flexible, high-sensitivity, material-independent, low-cost, noninvasive tool for monitoring real-time refractive-index variation.

  10. Epoxy resins used to seal brachytherapy seed

    Energy Technology Data Exchange (ETDEWEB)

    Ferreira, Natalia Carolina Camargos; Ferraz, Wilmar Barbosa; Reis, Sergio Carneiro dos; Santos, Ana Maria Matildes dos, E-mail: nccf@cdtn.br, E-mail: ferrazw@cdtn.br, E-mail: reissc@cdtn.br, E-mail: amms@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, BH (Brazil)

    2013-07-01

    Prostate cancer treatment with brachytherapy is recommended for patients with cancer at an early stage. In this treatment, small radioactive seeds are implanted directly in the prostate gland. These seeds are composed at least of one radionuclide carrier and an X-ray marker enclosed within a metallic tube usually sealed by laser process. This process is expensive and, furthermore, it can provoke a partial volatilization of the radionuclide and change the isotropy in dose distribution around the seed. In this paper, we present a new sealing process using epoxy resin. Three kinds of resins were utilized and characterized by scanning electron microscopy (SEM), energy dispersive X ray (EDS) and by differential scanning calorimetry (DSC) after immersion in simulated body fluid (SBF) and in sodium iodine solution (NaI). The sealing process showed excellent potential to replace the sealing laser usually employed. (author)

  11. Organic fiber/epoxy pressure vessels

    Science.gov (United States)

    Chiao, T. T.; Hamstad, M. A.; Marcon, M. A.

    1974-01-01

    We evaluated the performance of an organic fiber in an epoxy matrix by winding 20-cm diam spherical and cylindrical pressure vessels of various designs. For the spherical vessels, we used soft aluminum liners 0.76 mm thick for a double boss design and 2 mm thick for a single boss design. For the cylindrical vessels, we used both 0.5-mm rubber liners and 0.76-mm soft aluminum liners. Vessels of both types were tested for burst pressure and cyclic fatigue at room temperature and liquid hydrogen temperature. The effects of temperature and vessel shape on the vessel performance factor were negligible. Our vessel fatigue data were marred by premature failure of the liners.

  12. Mitochondrial DNA deletion percentage in sun exposed and non sun exposed skin.

    Science.gov (United States)

    Powers, Julia M; Murphy, Gillian; Ralph, Nikki; O'Gorman, Susan M; Murphy, James E J

    2016-12-01

    The percentages of mitochondrial genomes carrying the mtDNA(3895) and the mtDNA(4977) (common) deletion were quantified in sun exposed and non sun exposed skin biopsies, for five cohorts of patients varying either in sun exposure profile, age or skin cancer status. Non-melanoma skin cancer diagnoses are rising in Ireland and worldwide [12] but most risk prediction is based on subjective visual estimations of sun exposure history. A quantitative objective test for pre-neoplastic markers may result in better adherence to sun protective behaviours. Mitochondrial DNA (mtDNA) is known to be subject to the loss of a significant proportion of specific sections of genetic code due to exposure to ultraviolet light in sunlight. Although one such deletion has been deemed more sensitive, another, called the mtDNA(4977) or common deletion, has proved to be a more useful indicator of possible risk in this study. Quantitative molecular analysis was carried out to determine the percentage of genomes carrying the deletion using non sun exposed and sun exposed skin biopsies in cohorts of patients with high or low sun exposure profiles and two high exposure groups undergoing treatment for NMSC. Results indicate that mtDNA deletions correlate to sun exposure; in groups with high sun exposure habits a significant increase in deletion number in exposed over non sun exposed skin occurred. An increase in deletion percentage was also seen in older cohorts compared to the younger group. The mtDNA(3895) deletion was detected in small amounts in exposed skin of many patients, the mtDNA(4977) common deletion, although present to some extent in non sun exposed skin, is suggested to be the more reliable and easily detected marker. In all cohorts except the younger group with relatively lower sun exposure, the mtDNA(4977) deletion was more frequent in sun exposed skin samples compared to non-sun exposed skin.

  13. Gravitational Lensing Characteristics of the Transparent Sun

    CERN Document Server

    Patla, Bijunath

    2007-01-01

    The transparent Sun is modeled as a spherically symmetric and centrally condensed gravitational lens using recent Standard Solar Model (SSM) data. The Sun's minimum focal length is computed to a refined accuracy of 23.5 +/- 0.1 AU, just beyond the orbit of Uranus. The Sun creates a single image of a distant point source visible to observers inside this minimum focal length and to observers sufficiently removed from the line connecting the source through the Sun's center. Regions of space are mapped where three images of a distant point source are created, along with their associated magnifications. Solar caustics, critical curves, and Einstein rings are computed and discussed. Extremely high gravitational lens magnifications exist for observers situated so that an angularly small, unlensed source appears near a three-image caustic. Types of radiations that might undergo significant solar lens magnifications as they can traverse the core of the Sun, including neutrinos and gravitational radiation, are discusse...

  14. Vibration Based Sun Gear Damage Detection

    Science.gov (United States)

    Hood, Adrian; LaBerge, Kelsen; Lewicki, David; Pines, Darryll

    2013-01-01

    Seeded fault experiments were conducted on the planetary stage of an OH-58C helicopter transmission. Two vibration based methods are discussed that isolate the dynamics of the sun gear from that of the planet gears, bearings, input spiral bevel stage, and other components in and around the gearbox. Three damaged sun gears: two spalled and one cracked, serve as the focus of this current work. A non-sequential vibration separation algorithm was developed and the resulting signals analyzed. The second method uses only the time synchronously averaged data but takes advantage of the signal/source mapping required for vibration separation. Both algorithms were successful in identifying the spall damage. Sun gear damage was confirmed by the presence of sun mesh groups. The sun tooth crack condition was inconclusive.

  15. Sun Safe Mode Controller Design for LADEE

    Science.gov (United States)

    Fusco, Jesse C.; Swei, Sean S. M.; Nakamura, Robert H.

    2015-01-01

    This paper presents the development of sun safe controllers which are designed to keep the spacecraft power positive and thermally balanced in the event an anomaly is detected. Employed by NASA's Lunar Atmosphere and Dust Environment Explorer (LADEE), the controllers utilize the measured sun vector and the spacecraft body rates for feedback control. To improve the accuracy of sun vector estimation, the least square minimization approach is applied to process the sensor data, which is proven to be effective and accurate. To validate the controllers, the LADEE spacecraft model engaging the sun safe mode was first simulated and then compared with the actual LADEE orbital fight data. The results demonstrated the applicability of the proposed sun safe controllers.

  16. Missions and Moral Judgement.

    Science.gov (United States)

    Bushnell, Amy Turner

    2000-01-01

    Addresses the history of Spanish-American missions, discussing the view of missions in church history, their role in the Spanish conquest, and the role and ideas of Herbert E. Bolton. Focuses on differences among Spanish borderlands missions, paying particular attention to the Florida missions. (CMK)

  17. Curing of Epoxy Resin Induced by Femtosecond Laser Pulse

    Institute of Scientific and Technical Information of China (English)

    LI Yubin; ZHANG Zuoguang

    2005-01-01

    The possibility of curing of epoxy resin induced by femtosecond laser beam was explored through choosing different initiators . Absorption spectroscopy, infrared spectroscopy (IR), stereomicroscopy and scanning electron microscopy (SEM) were applied to analyze the structure of epoxy resin systems after irradiation with a femtosecond laser beam. The experimental results show that the epoxy resin systems containing diaryliodonium salts can be cured by irradiation of Jemtosecond laser pulse, while the systems containing benzoin can not be cured. It is found that diaryliodonium salts decompose under the irradiation of femtosecond laser pulse through multi ( two ) -photon absorption, initiating the ring-opening polymerization of epoxy resin. And the appearance of cured area has a sheet structure consisting of many tiny lamellar structures.

  18. Dispersion and reinforcing mechanism of carbon nanotubes in epoxy nanocomposites

    Indian Academy of Sciences (India)

    Smrutisikha Bal

    2010-02-01

    Carbon nanotube based epoxy composites have been fabricated at room temperature and refrigeration process using sonication principle. Flexural moduli, electrical conductivity, glass transition temperature of epoxy resin as well as nanocomposite samples have been determined. Distribution behaviour of carbon nanotubes in the epoxy matrix was examined through scanning electron microscopy. Composite samples showed better properties than resin samples due to strengthening effect of the filled nanotubes. Refrigerated nanocomposites obtained increasing mechanical property because of better dispersion due to low temperature settlement of polymers. Improvement of electrical conductivity was due to the fact that aggregated phases form a conductive three-dimensional network throughout the whole sample. The increasing glass transition temperature was indicative of restricting movement of polymer chains that ascribe strong interaction presented between carbon nanotubes and epoxy chains that was again supplemented by Raman study and SEM.

  19. Autonomic healing of carbon fiber/epoxy interfaces.

    Science.gov (United States)

    Jones, Amanda R; Cintora, Alicia; White, Scott R; Sottos, Nancy R

    2014-05-14

    A maximum of 91% recovery of interfacial shear strength (IFSS) is achieved for carbon fiber/epoxy interfaces functionalized with capsules containing reactive epoxy resin and ethyl phenyl acetate (EPA). We find a binder is necessary to improve the retention of capsules on the carbon fiber surface. Two different methods for applying the binder to the carbon fiber surface are investigated. Healing efficiency is assessed by recovery of IFSS of a single functionalized fiber embedded in a microdroplet of epoxy. Debonding of the fiber/matrix interface ruptures the capsules, releasing resin and EPA solvent into the crack plane. The solvent swells the matrix, initiating transport of residual amine functionality from the matrix for further curing with the epoxy resin delivered to the crack plane. The two binder protocols produce comparable results, both yielding higher recovery of IFSS than samples prepared without a binder.

  20. Epoxy resin developments for large superconducting magnets impregnation

    Science.gov (United States)

    Rey, J. M.; Gallet, B.; Kircher, F.; Lottin, J. C.

    The future detectors ATLAS and CMS of the Large Hadron Collider at CERN will use two huge superconducting magnets. Both are now under design, and their electrical insulation could be realized using epoxy resin and a wet impregnation technique. Because of their large dimensions, and the indirect cooling of the superconductor, the strengths of the resin and of the resin/conductor interface are of major importance. A new generation of epoxy resins for vacuum/pressure impregnation methods has been tested, and compared with some classical and well-known epoxy resins used in impregnation techniques. In order to understand the mechanical behaviour at 4 K, the complete evolution from liquid state to low temperature service condition is considered. The paper will present some results on the mechanical properties, the density and the chemical shrinkage occurring during the polymerization and the thermal contraction between room temperature and 4 K for these different types of epoxy resins.

  1. Electrical and Mechanical Characteristics of Epoxy-Nanoclay Composite

    Science.gov (United States)

    Noh, Hyun-Ji; Nam, Sung-Pill; Lee, Sung-Gap; Ahn, Byeong-Lib; Won, Woo-Sik; Woo, Hyoung-Gwan; Park, Sang-Man

    In this study, we investigated the effects of nanoclay additives on the electrical and mechanical properties of diglycidyl ether of bisphenol A (DGEBA) epoxy resin. Epoxy-clay nanocomposites were synthesized using organically modified two montmorillonite clays (MMT) with different interlamellar spacing (31.5 Å and 18.5 Å). The electrical and mechanical properties of epoxy-clay nanocopomosites were measured with variation of the amount and type of clay. The nanocomposites were found to be homogenous materials although the nanocomposites still have clay aggregates with increasing nanoclay contents. The dielectric constant showed between 3.2 ~ 3.5 and the dielectric loss showed between 3.2 ~ 5.7% in all nanocoposites. The dielectric strength and tensile strength of the 5 wt% Cloisite 15A added epoxy-oclay nanocomposite were 23.9 kV/mm and 86.7 MPa, respectively.

  2. Waterborne Epoxy Nanocoatings Modified by Nanoemulsions and Nanoparticles

    National Research Council Canada - National Science Library

    Zhenyu Wang Enhou Han Fuchun Liu Zhouhai Qian Liwei Zhu

    2014-01-01

    .... In the present investigation electrically conductive nanocoatings were prepared by the incorporation of graphite, nano-SiO2 concentrate, acrylic nanoemulsion and fluorocarbon emulsion onto the waterborne epoxy polymer...

  3. Lipase catalyzed synthesis of epoxy-fatty acids

    Institute of Scientific and Technical Information of China (English)

    CHEN, Qian; LI, Zu-Yi

    2000-01-01

    Lipase catalyzed synthesis of epoxy-fatty acidas from unsaturated carboxylic acids was investigated.Under mild conditions unsaturated arboxylic acids were convcveed to peroxide,then the unsaturated peroxycarboxylic acids epoxidised the C=C bond of themselves

  4. Glass-ceramics and epoxy-composites for radiation imaging

    Energy Technology Data Exchange (ETDEWEB)

    Williams, G.V.M. [MacDiarmid Institute, Industrial Research, P.O. Box 31310, Lower Hutt (New Zealand)], E-mail: G.Williams@irl.cri.nz; Bittar, A. [MacDiarmid Institute, Industrial Research, P.O. Box 31310, Lower Hutt (New Zealand); Dotzler, C. [MacDiarmid Institute, Industrial Research, P.O. Box 31310, Lower Hutt (New Zealand); School of Chemical and Physical Sciences, Victoria University, P.O. Box 600, Wellington (New Zealand); Beaudin, A. [MacDiarmid Institute, Industrial Research, P.O. Box 31310, Lower Hutt (New Zealand); Varoy, C. [School of Chemical and Physical Sciences, Victoria University, P.O. Box 600, Wellington (New Zealand); Dunford, C. [MacDiarmid Institute, Industrial Research, P.O. Box 31310, Lower Hutt (New Zealand)

    2007-04-15

    We report the results of optical, photo-luminescence and spatial resolution measurements on glass-ceramic and epoxy-composite X-ray storage phosphors. We find that the optical extinction coefficient at the stimulation and emission wavelengths is dominated by scattering for all the samples studied. However, the extinction coefficient is at least an order of magnitude lower in ZBLAN:BaCl{sub 2}:Eu{sup 2+} glass-ceramics when compared with the epoxy/BaCl{sub 2}:Eu{sup 2+} composites. Significantly reduced scattering is found in a epoxy/KBr:Eu{sup 2+} composite due to the better match between the refractive indices of the epoxy and crystallite. We show that the spatial resolution using a confocal microscope readout in a ZBLAN:BaCl{sub 2}:Eu{sup 2+} glass-ceramic is below 10{mu}m and hence this glass-ceramic has potential applications in high resolution radiation imaging.

  5. Method of making superhydrophobic/superoleophilic paints, epoxies, and composites

    Energy Technology Data Exchange (ETDEWEB)

    Simpson, John T.; Hunter, Scott Robert

    2016-05-10

    Superhydrophobic paints and epoxies comprising superoleophilic particles and surfaces and methods of making the same are described. The superoleophilic particles can include porous particles having a hydrophobic coating layer deposited thereon. superoleophilic particles.

  6. Finite Element Analysis Of Epoxy-Graphite Powder, Epoxy-Ms Powder, Epoxy- Ms Lathe Scrap(Ms Flakes Filled In A Circular Hollow Aluminium Column

    Directory of Open Access Journals (Sweden)

    Dr.M.AnandaRao

    2014-09-01

    Full Text Available Main objective of this paper is to prepare composite material filled hollow Al columns and test them for their compressive strengths and compare the results with Rankine’s columnar theory and Finite Element Analysis using Ansys 2014. The idea of filling the particulate polymer composite material in an aluminium tube is taken from a research paper presented at 14th international conference on computing in civil and building engineering in Moscow, Russia (27-29 June 2012 by Feng Zhou and Ben Young, in which they filled the Al tube with concrete and conducted Finite Elemental Analysis. The composites used in the project are Epoxy-graphite, Epoxy-MS powder, Epoxy-MS flakes, all these three samples are taken in a hollow Al CHS tube. Another two specimens were prepared by using epoxy-graphite powder and epoxy-MS powder without using Al tube. These specimens were subjected to crushing force and the readings obtained were compared with the results obtained by conducting Finite elemental analysis in ANSYS. The applications include columns in buildings, columns of bridges, and as columns in earthquake zones as the outer hollow metal has the capability to withstand heavy loads and dampens the vibrations.

  7. Rubber-Modified Epoxies. II. Morphology, Transitions, and Mechanical Properties.

    Science.gov (United States)

    1984-11-01

    tetrafunctional aromatic diamine-cured diglycidyl ether of bisphenol A ( DGEBA )-type epoxy resin was selected as the neat system because of its high ETgm (1670C...was a DGEBA -type epoxy resin (DER 331, Dow Chemical Co.) cured with tri- methylene glycol di-p-aminobenzoate (ITMABO, i.e. Polacure 740M, Polaroid...Chemical "o.) with excess of DGEBA resin. The second system, denoted DTAxl6, was iodified with a commercial amino-terminated butadiene-acrylonitrile

  8. Adherend Surface Effects on Epoxy Cure by NMR

    Science.gov (United States)

    1994-05-11

    questions. 3 2. Summary of results. The structure and dynamics of the cure of the epoxy resin system based on the diglycidyl ether of bisphenol-A ( DGEBA ) is... DGEBA ), obtained from Dow Chemical Co. (der 332) was heated in the oven at temperature 160 OC until completely melted. The sample was cooled and at the...epoxy to ether conversion with the NMR analysis. (b) Results and Interpretation. The mixture of DGEBA with DDS was studied at temperature 1600C. The

  9. Exit Presentation: Infrared Thermography on Graphite/Epoxy

    Science.gov (United States)

    Comeaux, Kayla

    2010-01-01

    This slide presentation reports on the internship project that was accomplished during the summer of 2010. The objectives of the project were to: (1) Simulate Flash Thermography on Graphite/Epoxy Flat Bottom hole Specimen and thin void specimens, (2) Obtain Flash Thermography data on Graphite/Epoxy flat bottom hole specimens, (3) Compare experimental results with simulation results, Compare Flat Bottom Hole Simulation with Thin Void Simulation to create a graph to determine size of IR Thermography detected defects

  10. Properties of Graphene Oxide/Epoxy Resin Composites

    OpenAIRE

    Jijun Tang; Haijun Zhou; Yunxia Liang; Xinlan Shi; Xin Yang; Jiaoxia Zhang

    2014-01-01

    The graphene oxide (GO) was obtained by pressurized oxidation method using natural graphite as raw materials. Then the GO/epoxy resin composites were prepared by casting. The mechanical and damping properties of composites were studied. As a result, the impact intensity of GO/epoxy resin composites was prominently improved with the content of the graphene oxide increasing. The glass transition temperature decreased and the damping capacity is improved.

  11. Microstructure, elastic and electromagnetic properties of epoxy-graphite composites

    OpenAIRE

    Bellucci, S.; Micciulla, F.; V. M. Levin; Yu. S. Petronyuk; Chernozatonskii, L. A.; Kuzhir, P. P.; Paddubskaya, A. G.; Macutkevic, J.; M. A. Pletnev; Fierro, V.; A. Celzard

    2015-01-01

    A set of epoxy resin-based composites filled with 0.25 – 2.0 wt.% of commercially available exfoliated graphite (EG) and thick graphene (TG), prepared by suspending EG particles in cyclohexane, and submitting the suspension to a series of grinding and ultrasonic dispersion steps, was produced. The microstructure of such epoxy-graphite composites has been studied by the impulse acoustic microscopy technique. According to acoustic microscopy data, exfoliated graphite microparticles have been we...

  12. Properties of Graphene Oxide/Epoxy Resin Composites

    OpenAIRE

    Jijun Tang; Haijun Zhou; Yunxia Liang; Xinlan Shi; Xin Yang; Jiaoxia Zhang

    2014-01-01

    The graphene oxide (GO) was obtained by pressurized oxidation method using natural graphite as raw materials. Then the GO/epoxy resin composites were prepared by casting. The mechanical and damping properties of composites were studied. As a result, the impact intensity of GO/epoxy resin composites was prominently improved with the content of the graphene oxide increasing. The glass transition temperature decreased and the damping capacity is improved.

  13. Properties of Graphene Oxide/Epoxy Resin Composites

    Directory of Open Access Journals (Sweden)

    Jijun Tang

    2014-01-01

    Full Text Available The graphene oxide (GO was obtained by pressurized oxidation method using natural graphite as raw materials. Then the GO/epoxy resin composites were prepared by casting. The mechanical and damping properties of composites were studied. As a result, the impact intensity of GO/epoxy resin composites was prominently improved with the content of the graphene oxide increasing. The glass transition temperature decreased and the damping capacity is improved.

  14. Bio-Based Aromatic Epoxy Monomers for Thermoset Materials.

    Science.gov (United States)

    Ng, Feifei; Couture, Guillaume; Philippe, Coralie; Boutevin, Bernard; Caillol, Sylvain

    2017-01-18

    The synthesis of polymers from renewable resources is a burning issue that is actively investigated. Polyepoxide networks constitute a major class of thermosetting polymers and are extensively used as coatings, electronic materials, adhesives. Owing to their outstanding mechanical and electrical properties, chemical resistance, adhesion, and minimal shrinkage after curing, they are used in structural applications as well. Most of these thermosets are industrially manufactured from bisphenol A (BPA), a substance that was initially synthesized as a chemical estrogen. The awareness on BPA toxicity combined with the limited availability and volatile cost of fossil resources and the non-recyclability of thermosets implies necessary changes in the field of epoxy networks. Thus, substitution of BPA has witnessed an increasing number of studies both from the academic and industrial sides. This review proposes to give an overview of the reported aromatic multifunctional epoxide building blocks synthesized from biomass or from molecules that could be obtained from transformed biomass. After a reminder of the main glycidylation routes and mechanisms and the recent knowledge on BPA toxicity and legal issues, this review will provide a brief description of the main natural sources of aromatic molecules. The different epoxy prepolymers will then be organized from simple, mono-aromatic di-epoxy, to mono-aromatic poly-epoxy, to di-aromatic di-epoxy compounds, and finally to derivatives possessing numerous aromatic rings and epoxy groups.

  15. Bio-Based Aromatic Epoxy Monomers for Thermoset Materials

    Directory of Open Access Journals (Sweden)

    Feifei Ng

    2017-01-01

    Full Text Available The synthesis of polymers from renewable resources is a burning issue that is actively investigated. Polyepoxide networks constitute a major class of thermosetting polymers and are extensively used as coatings, electronic materials, adhesives. Owing to their outstanding mechanical and electrical properties, chemical resistance, adhesion, and minimal shrinkage after curing, they are used in structural applications as well. Most of these thermosets are industrially manufactured from bisphenol A (BPA, a substance that was initially synthesized as a chemical estrogen. The awareness on BPA toxicity combined with the limited availability and volatile cost of fossil resources and the non-recyclability of thermosets implies necessary changes in the field of epoxy networks. Thus, substitution of BPA has witnessed an increasing number of studies both from the academic and industrial sides. This review proposes to give an overview of the reported aromatic multifunctional epoxide building blocks synthesized from biomass or from molecules that could be obtained from transformed biomass. After a reminder of the main glycidylation routes and mechanisms and the recent knowledge on BPA toxicity and legal issues, this review will provide a brief description of the main natural sources of aromatic molecules. The different epoxy prepolymers will then be organized from simple, mono-aromatic di-epoxy, to mono-aromatic poly-epoxy, to di-aromatic di-epoxy compounds, and finally to derivatives possessing numerous aromatic rings and epoxy groups.

  16. Thermo-curable epoxy systems for nanoimprint lithography

    Science.gov (United States)

    Wu, Chun-Chang; Lien-Chung Hsu, Steve

    2010-01-01

    In this work, we have used solvent-free thermo-curable epoxy systems for low-pressure and moderate-temperature nanoimprint lithography (NIL). The curing kinetic parameters and conversion of diglycidyl ether of bisphenol A (DGEBA) resin with different ambient-cure 930 and 954 hardeners were studied by the isothermal DSC technique. They are useful for the study of epoxy resins in the imprinting application. The DGEBA/930 and DGEBA/954 epoxy resists can be imprinted to obtain high-density nano- and micro-scale patterns on a flexible indium tin oxide/poly(ethylene terephthalate) (ITO/PET) substrate. The DGEBA/930 epoxy resin is not only suitable for resist material, but also for plastic mold material. Highly dense nanometer patterns can be successfully imprinted using a UV-curable resist from the DGEBA/930 epoxy mold. Using the replicated DGEBA/930 epoxy mold instead of the expensive master can prevent brittle failure of the silicon molds in the NIL.

  17. Microstructure, elastic and electromagnetic properties of epoxy-graphite composites

    Science.gov (United States)

    Bellucci, S.; Micciulla, F.; Levin, V. M.; Petronyuk, Yu. S.; Chernozatonskii, L. A.; Kuzhir, P. P.; Paddubskaya, A. G.; Macutkevic, J.; Pletnev, M. A.; Fierro, V.; Celzard, A.

    2015-06-01

    A set of epoxy resin-based composites filled with 0.25 - 2.0 wt.% of commercially available exfoliated graphite (EG) and thick graphene (TG), prepared by suspending EG particles in cyclohexane, and submitting the suspension to a series of grinding and ultrasonic dispersion steps, was produced. The microstructure of such epoxy-graphite composites has been studied by the impulse acoustic microscopy technique. According to acoustic microscopy data, exfoliated graphite microparticles have been well dispersed in the epoxy matrix. TG nanoflakes demonstrated persistent tendency to clustering and formation of agglomerates. The addition of graphite particles in small amount (0.25 - 2.0 wt.%) did not influence the bulk elastic properties of epoxy-graphite composite materials. Being extremely lightweight, 0.003 g cm-3, EG had a lower percolation threshold than TG, at the level of 1-1.5 wt.% against 2.1-3.2 wt.%, respectively. As a result, epoxy composites filled with 1.0-2.0 wt.% EG provided high electromagnetic (EM) interference shielding both at microwave and THz frequencies. In contrast, no significant influence of TG loading was observed at low weight fraction (up to 2 wt.%) on the EM performance of epoxy composites.

  18. Microstructure, elastic and electromagnetic properties of epoxy-graphite composites

    Directory of Open Access Journals (Sweden)

    S. Bellucci

    2015-06-01

    Full Text Available A set of epoxy resin-based composites filled with 0.25 – 2.0 wt.% of commercially available exfoliated graphite (EG and thick graphene (TG, prepared by suspending EG particles in cyclohexane, and submitting the suspension to a series of grinding and ultrasonic dispersion steps, was produced. The microstructure of such epoxy-graphite composites has been studied by the impulse acoustic microscopy technique. According to acoustic microscopy data, exfoliated graphite microparticles have been well dispersed in the epoxy matrix. TG nanoflakes demonstrated persistent tendency to clustering and formation of agglomerates. The addition of graphite particles in small amount (0.25 – 2.0 wt.% did not influence the bulk elastic properties of epoxy-graphite composite materials. Being extremely lightweight, 0.003 g cm−3, EG had a lower percolation threshold than TG, at the level of 1-1.5 wt.% against 2.1-3.2 wt.%, respectively. As a result, epoxy composites filled with 1.0-2.0 wt.% EG provided high electromagnetic (EM interference shielding both at microwave and THz frequencies. In contrast, no significant influence of TG loading was observed at low weight fraction (up to 2 wt.% on the EM performance of epoxy composites.

  19. Characterization of Epoxy Composites Reinforced with Wax Encapsulated Microcrystalline Cellulose

    Directory of Open Access Journals (Sweden)

    Yuanfeng Pan

    2016-11-01

    Full Text Available The effect of paraffin wax encapsulated microcrystalline cellulose (EMC particles on the mechanical and physical properties of EMC/epoxy composites were investigated. It was demonstrated that the compatibility between cellulose and epoxy resin could be maintained due to partial encapsulation resulting in an improvement in epoxy composite mechanical properties. This work was unique because it was possible to improve the physical and mechanical properties of the EMC/epoxy composites while encapsulating the microcrystalline cellulose (MCC for a more homogeneous dispersion. The addition of EMC could increase the stiffness of epoxy composites, especially when the composites were wet. The 1% EMC loading with a 1:2 ratio of wax:MCC demonstrated the best reinforcement for both dry and wet properties. The decomposition temperature of epoxy was preserved up to a 5% EMC loading and for different wax:MCC ratios. An increase in wax encapsulated cellulose loading did increase water absorption but overall this absorption was still low (<1% for all composites.

  20. Interface and properties of epoxy resin modified by elastomeric nano-particles

    Institute of Scientific and Technical Information of China (English)

    HUANG Fan; LIU Yiqun; ZHANG Xiaohong; GAO Jianming; SONG Zhihai; TANG Banghui; WEI Genshuan; QIAO Jinliang

    2005-01-01

    Study on a new composite of epoxy resin/elastomeric nano-particles (ENP) is reported in this paper, which shows that, in comparison with pure epoxy resin and epoxy toughened with CTBN, the composites of epoxy resin/carboxylic nitrile-butadiene ENP and epoxy resin/styrene butadiene vinyl-pyridine ENP possess both higher toughness and heat resistance. Both ENPs used in the study have an average size of less than 100 nm. Study on the epoxy network's morphology and interface properties suggests that due to the chemical reaction between ENP and epoxy resin and more hydrogen bonds between nitrile groups of the rubber and hydroxyl groups of the epoxy resin, stronger interaction at the larger interface may lead to the observed excellent properties of the epoxy resin toughened with ENP.

  1. The First Focused Hard X-Ray Images of the Sun With NuSTAR

    DEFF Research Database (Denmark)

    Grefenstette, Brian W.; Glesener, Lindsay; Krucker, Sam

    2016-01-01

    We present results from the the first campaign of dedicated solar observations undertaken by the Nuclear Spectroscopic Telescope ARray (NuSTAR) hard X-ray (HXR) telescope. Designed as an astrophysics mission, NuSTAR nonetheless has the capability of directly imaging the Sun at HXR energies (>3 ke......V) with an increase in sensitivity of at least two magnitude compared to current non-focusing telescopes. In this paper we describe the scientific areas where NuSTAR will make major improvements on existing solar measurements. We report on the techniques used to observe the Sun with NuSTAR, their limitations......, and full-disk HXR images of the Sun....

  2. The First Focused Hard X-Ray Images of the Sun With NuSTAR

    DEFF Research Database (Denmark)

    Grefenstette, Brian W.; Glesener, Lindsay; Krucker, Sam

    2016-01-01

    We present results from the the first campaign of dedicated solar observations undertaken by the Nuclear Spectroscopic Telescope ARray (NuSTAR) hard X-ray (HXR) telescope. Designed as an astrophysics mission, NuSTAR nonetheless has the capability of directly imaging the Sun at HXR energies (>3 ke......V) with an increase in sensitivity of at least two magnitude compared to current non-focusing telescopes. In this paper we describe the scientific areas where NuSTAR will make major improvements on existing solar measurements. We report on the techniques used to observe the Sun with NuSTAR, their limitations......, and full-disk HXR images of the Sun....

  3. The Sun and How to Observe It

    CERN Document Server

    Jenkins, Jamey L

    2009-01-01

    Without the Sun, all life on Earth would perish. But what exactly do we know about this star that lights, heats, and powers Earth? Actually, we know quite a lot, thanks mainly to a host of eager solar observers. Looking directly at the Sun is EXTREMELY hazardous. But many astronomers, both professional and amateur, have found ways to view the Sun safely to learn about it. You, too, can view the Sun in all of its glorious detail. Some of the newest, most exciting telescopes on the market are affordable to amateur astronomers or even just curious sky watchers, and with this guide to what the Sun has to offer, including sunspots, prominences, and flares, plus reviews of the latest instruments for seeing and capturing images of the Sun, you can contribute to humankind’s knowledge of this immense ball of glowing gases that gives us all life. For a complete guide to Sun viewing, see also Total Solar Eclipses and How to Observe Them (2007) by Martin Mobberley in this same series.

  4. Sun-synchronous satellite orbit determination

    Science.gov (United States)

    Ma, Der-Ming; Zhai, Shen-You

    2004-02-01

    The linearized dynamic equations used for on-board orbit determination of Sun-synchronous satellite are derived. Sun-synchronous orbits are orbits with the secular rate of the right ascension of the ascending node equal to the right ascension rate of the mean sun. Therefore the orbit is no more a closed circle but a tight helix about the Earth. In the paper, instead of treating the orbit as a closed circle, the actual helix orbit is taken as nominal trajectory. The details of the linearized equations of motion for the satellite in the Sun-synchronous orbit are derived. The linearized equations are obtained by perturbing the Keplerian motion with the J2 correction and the effect of sun's attraction being neglected. Combined with the GPS navigation equations, the Kalman filter formulation is given. The particular application considered is the circular Sun-synchronous orbit with the altitude of 800 km and inclination of 98.6°. The numerical example simulated by MATLAB® shows that only the pseudo-range data used in the algorithm still gives acceptable results. Based on the simulation results, we can use the on-board GPS receivers' signal only as an alternative to determine the orbit of Sun-Synchronous satellite and therefore circumvents the need for extensive ground support.

  5. Effect of carbon nanotube addition on the wear behavior of basalt/epoxy woven composites.

    Science.gov (United States)

    Kim, M T; Rhee, K Y; Lee, B H; Kim, C J

    2013-08-01

    The effect of acid-treated carbon nanotube (CNT) addition on the wear and dynamic mechanical thermal properties of basalt/epoxy woven composites was investigated in this study. Basalt/CNT/epoxy composites were fabricated by impregnating woven basalt fibers into epoxy resin mixed with 1 wt% CNTs which were acid-treated. Wear and DMA (dynamic mechanical analyzer) tests were performed on basalt/epoxy composites and basalt/CNT/epoxy composites. The results showed that the addition of the acid-treated CNTs improved the wear properties of basalt/epoxy woven composites. Specifically, the friction coefficient of the basalt/epoxy composite was stabilized in the range of 0.5-0.6 while it fell in the range of 0.3-0.4 for basalt/CNT/epoxy composites. The wear volume loss of the basalt/CNT/epoxy composites was approximately 68% lower than that of the basalt/epoxy composites. The results also showed that the glass transition temperature of basalt/CNT/epoxy composites was higher than that of basalt/epoxy composites. The improvement of wear properties of basalt/epoxy composites by the addition of acid-treated CNTs was caused by the homogeneous load transfer between basalt fibers and epoxy matrix due to the reinforcement of CNTs.

  6. Anisotropic microstructure near the sun

    Science.gov (United States)

    Coles, W. A.; Grall, R. R.; Spangler, S. R.; Sakurai, T.; Harmon, J. K.

    1996-07-01

    Radio scattering observations provide a means of measuring a two-dimensional projection of the three-dimensional spatial spectrum of electron density, i.e., in the plane perpendicular to the line of sight. Earlier observations have shown that the microstructure at scales of the order of 10 km becomes highly field-aligned inside of 10 Rsolar [Armstrong et al., 1990]. Earlier work has also shown that density fluctuations at scales larger than 1000 km have a Kolmogorov spectrum, whereas the smaller scale structure has a flatter spectrum and is considerably enhanced above the Kolmogorov ``background'' [Coles et al., 1991]. Here we present new observations made during 1990 and 1992. These confirm the earlier work, which was restricted to one source on a few days, but they suggest that the anisotropy changes abruptly near 6 Rsolar which was not clear in the earlier data. The axial ratio measurements are shown on Figure 1 below. The new observations were made with a more uniform sampling of the spatial plane. They show that contours of constant correlation are elliptical. This is apparently inconsistent with the spatial correlation of the ISEE-3 magnetic field which shows a ``Maltese Cross'' shape [Matthaeus et al., 1990]. However this inconsistency may be only apparent: the magnetic field and density correlations need not have the same shape; the scale of the magnetic field correlations is at least 4 orders of magnitude larger; they are much further from the sun; and they are point measurements whereas ours are path-integrated. We also made two simultaneous measurements, at 10 Rsolar, of the anisotropy on scales of 200 to 4000 km. Significant anisotropy was seen on the smaller scales, but the larger scale structure was essentially isotropic. This suggests that the process responsible for the anisotropic microstructure is independent of the larger scale isotropic turbulence. It is then tempting to speculate that the damping of this anisotropic process inside of 6 Rsolar

  7. Perspectives on the Interior of the Sun

    Indian Academy of Sciences (India)

    S. Μ. Chitre

    2000-09-01

    The interior of the Sun is not directly accessible to observations. Nonetheless, it is possible to infer the physical conditions inside the Sun with the help of structure equations governing its equilibrium and with the powerful observational tools provided by the neutrino fluxes and oscillation frequencies. The helioseismic data show that the internal constitution of the Sun can be adequately represented by a standard solar model. It turns out that a cooler solar core is not a viable solution for the measured deficit of neutrino fluxes, and the resolution of the solar neutrino puzzle should be sought in the realm of particle physics.

  8. The Jovian period in the Sun?

    Science.gov (United States)

    Kotov, V. A.

    2015-09-01

    The 41-year measurements of the Doppler effect of the photosphere performed at the Crimean Astrophysical Observatory, discovered two periods of global oscillations of the Sun: 9600.606(12) s and 9597.929(15) s. Their beat period, 398.4(2.9) d, well agrees with a synodic orbital period of Jupiter, PJ = 398.9 d, raising a new problem for solar physics, cosmogony and cosmology. A hypothesis is advanced that the PJ beating of the Sun is induced by gravitation of Jupiter, revolving in a privileged reference system "the Sun - the Earth".

  9. Semiautomatic sun shots with the WIDIF DIflux

    Science.gov (United States)

    Rasson, Jean L.; Hendrickx, Olivier; Marin, Jean-Luc

    2017-07-01

    The determination of magnetic declination angle entails finding two directions: geographic north and magnetic north. This paper deals with the former. The known way to do it by using the sun's calculable orientation in the sky is improved by using a device based on a WIDIF DIflux theodolite and split photocells positioned on its telescope ocular. Given the WIDIF accurate timing and location provided by the onboard GPS receiver, an astronomical computation can be effected to accurately and quickly determine the sun's azimuth and an auxiliary mark's azimuth. The precise sun's crossing of the split photocell, amplified by the telescope's magnification, allows azimuth accuracies of a few seconds of arc.

  10. Temperature restrictions for materials used in aerospace industry for the near-sun orbits

    CERN Document Server

    Ancona, Elena

    2016-01-01

    For near-Sun missions, the spacecraft approaches very close to the Sun and space environmental effects become relevant. Strong restrictions on how much close it can get derive from the maximum temperature that the used materials can stand, in order not to compromise the spacecraft's activity and functionalities. In other words, the minimum perihelion distance of a given mission can be determined based on the materials' temperature restrictions. The temperature of an object in space depends on its optical properties: reflectivity, absorptivity, transmissivity, and emissivity. Usually, it is considered as an approximation that the optical properties of materials are constant. However, emissivity depends on temperature. The consideration of the temperature dependence of emissivity and conductivity of materials used in the aerospace industry leads to the conclusion that the temperature dependence on the heliocentric distance is different from the case of constant optical properties [1]. Particularly, taking into ...

  11. Fatigue life extension of epoxy materials using ultrafast epoxy-SbF5 healing system introduced by manual infiltration

    Directory of Open Access Journals (Sweden)

    X. J. Ye

    2015-03-01

    Full Text Available The present paper is devoted to the verification of the capability of epoxy-SbF5 system as a healing chemistry for rapidly retarding and/or arresting fatigue cracks in epoxy materials at room temperature. Owing to the very fast curing speed of epoxy catalyzed by SbF5, epoxy monomer and the hardener (ethanol solution of SbF5–ethanol complex are successively infiltrated into the fracture plane under cyclic loading during the tension-tension fatigue test. As a result, the mechanisms including hydrodynamic pressure crack tip shielding, polymeric wedge and adhesive bonding of the healing agent are revealed. It is found that the healing agent forms solidified wedge at the crack tip within 20 s after start of polymerization of the epoxy monomer, so that the highest healing effect is offered at the moment. The epoxy-SbF5 system proves to be effective in rapidly obstructing fatigue crack propagation (despite that its cured version has lower fracture toughness than the matrix, and satisfies the requirement of constructing fast self-healing polymeric materials.

  12. Design and Analysis of Drive Shaft using Kevlar/Epoxy and Glass/Epoxy as a Composite Material

    Science.gov (United States)

    Karthikeyan, P.; Gobinath, R.; Kumar, L. Ajith; Jenish, D. Xavier

    2017-05-01

    In automobile industry drive shaft is one of the most important components to transmit power form the engine to rear wheel through the differential gear. Generally steel drive shaft is used in automobile industry, nowadays they are more interested to replace steel drive shaft with that of composite drive shaft. The overall objective of this paper is to analyze the composite drive shaft using to find out the best replacement for conventional steel drive shaft. The uses of advanced composite materials such as Kevlar, Graphite, Carbon and Glass with proper resins ware resulted in remarkable achievements in automobile industry because of its greater specific strength and specific modulus, improved fatigue and corrosion resistances and reduction in energy requirements due to reduction in weight as compared to steel shaft. This paper is to presents, the modeling and analysis of drive shaft using Kevlar/Epoxy and Glass/Epoxy as a composite material and to find best replacement for conventional steel drive shafts with an Kevlar/epoxy or Glass/Epoxy resin composite drive shaft. Modeling is done using CATIA software and Analysis is carried out by using ANSYS 10.0 software for easy understanding. The composite drive shaft reduces the weight by 81.67 % for Kevlar/Epoxy and 72.66% for Glass/Epoxy when compared with conventional steel drive shaft.

  13. Mission design options for human Mars missions

    Science.gov (United States)

    Wooster, Paul D.; Braun, Robert D.; Ahn, Jaemyung; Putnam, Zachary R.

    Trajectory options for conjunction-class human Mars missions are examined, including crewed Earth-Mars trajectories with the option for abort to Earth, with the intent of serving as a resource for mission designers. An analysis of the impact of Earth and Mars entry velocities on aeroassist systems is included, and constraints are suggested for interplanetary trajectories based upon aeroassist system capabilities.

  14. DISPERSION OF GRAPHENE OXIDE AND ITS FLAME RETARDANCY EFFECT ON EPOXY NANOCOMPOSITES

    Institute of Scientific and Technical Information of China (English)

    Zhou Wang; Xiu-zhi Tang; Zhong-zhen Yu; Peng Guo; Huai-he Song; Xu-sheng Du

    2011-01-01

    Grraphene oxide was prepared by ultrasonication of completely oxidized graphite and used to improve the flame retardancy of epoxy. The epoxy/graphene oxide nanocomposite was studied in terms of exfoliation/dispersion, thermal stability and flame retardancy. X-ray diffraction and transmission electron microscopy confirmed the exfoliation of the graphene oxide nanosheets in epoxy matrix. Cone calorimeter measurements showed that the time to ignition of the epoxy/graphene oxide nanocomposite was longer than that of neat epoxy. The heat release rate curve of the nanocomposite was broadened compared to that of neat epoxy and the peak heat release rate decreased as well.

  15. Experimental design applied optimization of a state in epoxy clay dispersion; Planejamento de experimentos aplicado a otimizacao do estado de dispersao de argilas em epoxi

    Energy Technology Data Exchange (ETDEWEB)

    Paz, Juliana D' Avila; Bertholdi, Jonas; Folgueras, Marilena Valadares; Pezin, Sergio Henrique; Coelho, Luiz Antonio Ferreira, E-mail: julianadpaz@yahoo.com.b [Universidade do Estado de Santa Catarina (UDESC), Joinville, SC (Brazil). Centro de Ciencias Tecnologicas

    2010-07-01

    This paper presents some analysis showed that the exfoliation / intercalation of a montmorillonite clay in epoxy resin such as viscosity, X-ray diffraction (XRD), scanning electron microscopy (SEM) and thermogravimetry (TG). Increasing the viscosity of epoxy resin diglycidyl ether bisphenol A with the addition of clay associated with the sonification system at the time of dispersion is a good indication of exfoliation. The X-ray diffraction already cured composite shows a decrease of crystallinity of clay and EDS microanalysis of SEM, non-uniform dispersion of clay in epoxy resin. Thermal analysis TG composite clay / epoxy shows an increase in thermal stability relative to pure epoxy. (author)

  16. Adhesion of PBO Fiber in Epoxy Composites

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The high mechanical and thermal performance of poly p-phenylene- 2, 6-benzobisoxazole ( PBO ) fiber provides great potential applications as reinforcement fibers for composites. A composite of PBO fiber and epoxy resin has excellent electrical insulation properties, therefore, it is considered to be the best choice for the reinforcement in high magnetic field coils for pulsed magnetic fields up to 100 T.However, poor adhesion between PBO fiber and matrix is found because of the chemically inactive and/or relatively smooth surface of the reinforcement fiber preventing efficient chemical bonding in the interface, which is a challenging issue to improve mechanical properties. Here, we report the surface modification of PBO fibers by ultraviolet (UV)irradiation, O2 and NH3 plasma, as well as acidic treatments. The interfacial adhesion strength values of all the treatments show the similar level as determined for aramid fibers by pull-out tests, a significant impact on fibermatrix-adhesion was not achieved. The surface free energy and roughness are increased for both sized and extracted fibers after plasma treatments together with maleic anhydride grafting. The sized fiber shows marginal improvement in adhesion strength and no change in fiber tensile strength because of the barrier effect of the finish.For the extracted fiber, different surface treatments either show no apparent effect or cause reduction in adhesion strength. Atomic force microscopy (AFM) topography analysis of the fracture surfaces proved adhesive failure at the fiber surface. The fiber surface roughness is increased and more surface flaws are induced, which could result in coarse interface structures when the treated fiber surface has no adequate wetting and functional groups. The adhesion failure is further confirmed by similar adhesion strength and compression shear strength values when the fiber was embedded in various epoxy resins with different temperature behavior. The tensile strength of fiber

  17. Innovations in mission architectures for exploration beyond low Earth orbit.

    Science.gov (United States)

    Cooke, D R; Joosten, B J; Lo, M W; Ford, K M; Hansen, R J

    2003-01-01

    Through the application of advanced technologies and mission concepts, architectures for missions beyond Earth orbit have been dramatically simplified. These concepts enable a stepping stone approach to science driven; technology enabled human and robotic exploration. Numbers and masses of vehicles required are greatly reduced, yet the pursuit of a broader range of science objectives is enabled. The scope of human missions considered range from the assembly and maintenance of large aperture telescopes for emplacement at the Sun-Earth libration point L2, to human missions to asteroids, the moon and Mars. The vehicle designs are developed for proof of concept, to validate mission approaches and understand the value of new technologies. The stepping stone approach employs an incremental buildup of capabilities, which allows for future decision points on exploration objectives. It enables testing of technologies to achieve greater reliability and understanding of costs for the next steps in exploration.

  18. Magnetic Flux Ropes from the Sun to 1 AU*

    Science.gov (United States)

    Krall, J.; Yurchyshyn, V. B.; St. Cyr, O. C.; Chen, J.

    2004-12-01

    Any practical model of the dynamics of a coronal mass ejection (CME) and its interplanetary counterpart (ICME) must conform to available observational constraints from sun and to the earth; the upcoming STEREO mission will add significantly to those constraints. We present model/data comparisons for specific CME/ICME events near the sun (using coronagraph image data) and in the heliosphere (using in situ measurements) to show that the flux rope model of Chen and Krall[1-2] provides an accurate physics-based characterization of flux-rope CMEs over this range. We further show that quantitative results, such as the field energy required for eruption, depend on specific aspects of the flux rope geometry, such as the ratio (length/width) of the elliptical shape traced out by the flux-rope axis. It is this geometry that will be determined, for the first time, by STEREO. [1] Chen, J. 1996, JGR, 101, 27499 [2] Krall, J. et al., 2000, ApJ, 539, 964 *Work supported by ONR, NASA and NSF

  19. A new view of the Sun from space

    CERN Document Server

    Bonnet, Roger Maurice

    2001-01-01

    Artificial Satellites are providing new tools for the observation of our star. The European Space Agency, ESA, in cooperation with NASA has programmed and developed three important space missions: SOHO, ULYSSES, and CLUSTER which offer new opportunities to study the Sun and how it influences the Earth's environment. SOHO in particular, thanks to an unprecedented stability together with a very complete set of instruments, has responded to several of the most fundamental questions concerning the behaviour and the running of our star. It is now possible to probe its interior down to the very core where the thermonuclear reactions occur and to deduce the physical conditions which exist therein. It is also possible to understand better the origin of the solar wind and why is the solar corona so hot. These two questions have been at the core of a large number of observations and theoretical studies for a long time. Thanks to ULYSSES which observes the Sun from a unique vantage point, outside the ecliptic plane wher...

  20. Predicting UV sky for future UV missions

    Science.gov (United States)

    Safonova, M.; Mohan, R.; Sreejith, A. G.; Murthy, Jayant

    2013-02-01

    Software simulators are now widely used in all areas of science, especially in application to astronomical missions: from instrument design to mission planning, and to data interpretation. We present a simulator to model the diffuse ultraviolet sky, where the different contributors are separately calculated and added together to produce a sky image of the size specified by the instrument requirements. Each of the contributors to the background, instrumental dark current, airglow, zodiacal light and diffuse Galactic light, depends on different factors. Airglow is dependent on the time of day; zodiacal light depends on the time of year, angle from the Sun and from the ecliptic; diffuse UV emission depends on the line of sight. To provide a full description of the sky along any line of sight, we have also added stars. The UV background light can dominate in many areas of the sky and severely limit viewing directions due to overbrightness. The simulator, available as a downloadable package and as a web-based tool, can be applied to preparation of real space missions and instruments. For demonstration, we present the example use for the two near-future UV missions: UVIT instrument on the Indian Astrosat mission and a new proposed wide-field (∼1000 square degrees) transient explorer satellite.

  1. Finding the lost siblings of the Sun

    Science.gov (United States)

    Liu, Cheng; Feltzing, Sofia; Ruchti, Gregory

    2014-01-01

    We have performed a spectral analysis on 18 stars solar sibling candidate. We found that only one one of the candidateshas solar metallicity and at the same time might have an age comparable to that of the Sun.

  2. Sun and Other Types of Radiation

    Science.gov (United States)

    ... What Causes Cancer? Sun and Other Types of Radiation Learn about the different types of radiation and ... other diseases. Learn more here. Other Types of Radiation Exposure Not all types of radiation have been ...

  3. Sun behaviour after cutaneous malignant melanoma

    DEFF Research Database (Denmark)

    Idorn, L W; Datta, P; Heydenreich, J

    2013-01-01

    Background  It has been reported that patients with cutaneous malignant melanoma (CMM) can lower their risk of a second primary melanoma by limiting recreational sun exposure. Previous studies based on questionnaires and objective surrogate measurements indicate that before their diagnosis......, patients with CMM are exposed to higher ultraviolet radiation (UVR) doses than controls, followed by a reduction after diagnosis. Objectives  In a prospective, observational case-control study, we aimed to assess sun exposure after diagnosis of CMM by objective measurements to substantiate advice about sun...... months and 6 years before the start of the study. During a summer season participants filled in sun exposure diaries daily and wore personal electronic UVR dosimeters in a wristwatch that continuously measured time-stamped UVR doses in standard erythema dose. Results  The UVR dose of recently diagnosed...

  4. UV Photography Shows Hidden Sun Damage

    Science.gov (United States)

    ... mcat1=de12", ]; for (var c = 0; c UV photography shows hidden sun damage A UV photograph gives ... developing skin cancer and prematurely aged skin. Normal photography UV photography 18 months of age: This boy's ...

  5. Nilaja Sun's "No Child...": Reflections on Success

    Science.gov (United States)

    Sun, Nilaja; Alexander, Phillip; Huldeen, Branden; Russell, Ron; Friedman, Melissa

    2007-01-01

    This article describes Nilaja Sun's groundbreaking one-woman show about a TA, her students, and her school, and includes interviews with the author/performer, an excerpt of the work, and a discussion of the organization behind it.

  6. The Sun murrab Baltimaadesse ja Soome

    Index Scriptorium Estoniae

    2008-01-01

    Aprillis andis ansambel Tanel Padar & The Sun Soomes, Lätis, Leedus ja Eestis üksteist kontserti. Heliplaadi "Here Gomes The Sun" lugu "Hopelessness You" on Soome raadiote tipp 300s neljakümnendal kohal, lugu "Learn the game" on Leedu FM99 raadios 33 enim mängitava loo seas, laul "One of those days" saavutas Läti raadio SWH rokkmuusika edetabelis teise koha.

  7. Optimal control of sun tracking solar concentrators

    Science.gov (United States)

    Hughes, R. O.

    1979-01-01

    Application of the modern control theory to derive an optimal sun tracking control for a point focusing solar concentrator is presented. A standard tracking problem converted to regulator problem using a sun rate input achieves an almost zero steady state tracking error with the optimal control formulation. However, these control techniques are costly because optimal type algorithms require large computing systems, thus they will be used mainly as comparison standards for other types of control algorithms and help in their development.

  8. The Sun murrab Baltimaadesse ja Soome

    Index Scriptorium Estoniae

    2008-01-01

    Aprillis andis ansambel Tanel Padar & The Sun Soomes, Lätis, Leedus ja Eestis üksteist kontserti. Heliplaadi "Here Gomes The Sun" lugu "Hopelessness You" on Soome raadiote tipp 300s neljakümnendal kohal, lugu "Learn the game" on Leedu FM99 raadios 33 enim mängitava loo seas, laul "One of those days" saavutas Läti raadio SWH rokkmuusika edetabelis teise koha.

  9. Dynamics and mission design near libration points

    CERN Document Server

    Gómez, G; Simo, C; Masdemont, J

    2001-01-01

    This book studies several problems related to the analysis of planned or possible spacecraft missions. It is divided into four chapters. The first chapter is devoted to the computation of quasiperiodic solutions for the motion of a spacecraft near the equilateral points of the Earth-Moon system. The second chapter gives a complete description of the orbits near the collinear point, L 1 , between the Earth and the Sun in the restricted three-body problem (RTBP) model. In the third chapter, methods are developed to compute the nominal orbit and to design and test the control strategy for the qua

  10. Cubesat Gravity Field Mission

    Science.gov (United States)

    Burla, Santoshkumar; Mueller, Vitali; Flury, Jakob; Jovanovic, Nemanja

    2016-04-01

    CHAMP, GRACE and GOCE missions have been successful in the field of satellite geodesy (especially to improve Earth's gravity field models) and have established the necessity towards the next generation gravity field missions. Especially, GRACE has shown its capabilities beyond any other gravity field missions. GRACE Follow-On mission is going to continue GRACE's legacy which is almost identical to GRACE mission with addition of laser interferometry. But these missions are not only quite expensive but also takes quite an effort to plan and to execute. Still there are few drawbacks such as under-sampling and incapability of exploring new ideas within a single mission (ex: to perform different orbit configurations with multi satellite mission(s) at different altitudes). The budget is the major limiting factor to build multi satellite mission(s). Here, we offer a solution to overcome these drawbacks using cubesat/ nanosatellite mission. Cubesats are widely used in research because they are cheaper, smaller in size and building them is easy and faster than bigger satellites. Here, we design a 3D model of GRACE like mission with available sensors and explain how the Attitude and Orbit Control System (AOCS) works. The expected accuracies on final results of gravity field are also explained here.

  11. Solar winds surfs waves in the Sun's atmosphere!

    Science.gov (United States)

    1999-07-01

    The fact that this electrified plasma speeds up to almost 3 million kilometres per hour as it leaves the Sun - twice as fast as originally predicted - has been known for years. The interpretation of how it happens is the real and surprising novelty: "The waves in the Sun's atmosphere are produced by vibrating solar magnetic field lines, which give solar wind particles a push just like an ocean wave gives a surfer a ride" said Dr John Kohl, principal investigator for the Ultraviolet Coronal Spectrometer (UVCS) - the instrument among the 12 aboard SOHO which gathered the data - and for the Spartan 201 mission. The outermost solar atmosphere, or corona, is only seen from Earth during a total eclipse of the Sun, when it appears as a shimmering, white veil surrounding the black lunar disc. The corona is an extremely tenuous, electrically charged gas, known as plasma, that flows throughout the solar system as the solar wind. The waves are formed by rapidly vibrating magnetic fields in the coronal plasma. They are called magneto - hydro - dynamic (MHD) waves and are believed to accelerate the solar wind. The solar wind is made up of electrons and ions, electrically charged atoms that have lost electrons. The electric charge of the solar wind particles forces them to travel along invisible lines of magnetic force in the corona. The particles spiral around the magnetic field lines as they rush into space. "The magnetic field acts like a violin string: when it's touched, it vibrates. When the Sun's magnetic field vibrates with a frequency equal to that of the particle spiraling around the magnetic field, it heats it up, producing a force that accelerates the particle upward and away from the Sun," says Dr. Ester Antonucci, an astronomer at the observatory of Turin, Italy, and co-investigator for SOHO's UVCS an instrument developed with considerable financial support by the Italian Space Agency, ASI. In a way this is similar to what happens if two people hold a string at

  12. Viscoelastic properties of graphene-based epoxy resins

    Science.gov (United States)

    Nobile, Maria Rossella; Fierro, Annalisa; Rosolia, Salvatore; Raimondo, Marialuigia; Lafdi, Khalid; Guadagno, Liberata

    2015-12-01

    In this paper the viscoelastic properties of an epoxy resin filled with graphene-based nanoparticles have been investigated in the liquid state, before curing, by means of a rotational rheometer equipped with a parallel plate geometry. Exfoliated graphite was prepared using traditional acid intercalation followed by a sudden treatment at high temperature (900°C). The percentage of exfoliated graphite was found to be 56%. The epoxy matrix was prepared by mixing a tetrafunctional precursor with a reactive diluent which produces a significant decrease in the viscosity of the epoxy precursor so that the dispersion step of nanofillers in the matrix can easily occur. The hardener agent, the 4,4-diaminodiphenyl sulfone (DDS), was added at a stoichiometric concentration with respect to all the epoxy rings. The inclusion of the partially exfoliated graphite (pEG) in the formulated epoxy mixture significantly modifies the rheological behaviour of the mixture itself. The epoxy mixture, indeed, shows a Newtonian behaviour while, at 3 wt % pEG content, the complex viscosity of the nanocomposite clearly shows a shear thinning behaviour with η* values much higher at the lower frequencies. The increase in complex viscosity with the increasing of the partially exfoliated graphite content was mostly caused by a dramatic increase in the storage modulus. All the graphene-based epoxy mixtures were cured by a two-stage curing cycles: a first isothermal stage was carried out at the lower temperature of 125°C for 1 hour while the second isothermal stage was performed at the higher temperature of 200°C for 3 hours. The mechanical properties of the cured nanocomposites show high values in the storage modulus and glass transition temperature.

  13. How to Observe the Sun Safely

    CERN Document Server

    Macdonald, Lee

    2012-01-01

    How to Observe the Sun Safely, Second Edition gives all the basic information and advice the amateur astronomer needs to get started in observing our own ever-fascinating star. Unlike many other astronomical objects, you do not need a large telescope or expensive equipment to observe the Sun. And it is possible to take excellent pictures of the Sun with today's low-cost digital cameras! This book surveys what is visible on the Sun and then describes how to record solar features and measure solar activity levels. There is also an account of how to use H-alpha and Calcium-K filters to observe and record prominences and other features of the solar chromosphere, the Sun's inner atmosphere. Because we are just entering a period of high activity on the Sun, following a long, quiet period, this is a great time to get involved with solar observing. Still emphasizing safety first, this Second Edition reflects recent and exciting advances in solar observing equipment. Chapters 6 through 8 have been completely revised ...

  14. Orientation in birds. The sun compass.

    Science.gov (United States)

    Schmidt-Koenig, K; Ganzhorn, J U; Ranvaud, R

    1991-01-01

    The sun compass was discovered by G. Kramer in caged birds showing migratory restlessness. Subsequent experiments with caged birds employing directional training and clock shifts, carried out by Hoffman and Schmidt-Koenig, showed that the sun azimuth is used, and the sun altitude ignored. In the laboratory, McDonald found the accuracy to be +/- 3 degrees(-)+/- 5 degrees. According to Hoffmann and Schmidt-Koenig, caged birds trained at medium northern latitudes were able to allow for the sun's apparent movement north of the arctic circle, but not in equatorial and trans-equatorial latitudes. In homing experiments, and employing clock shifts, Schmidt-Koenig demonstrated that the sun compass is used by homing pigeons during initial orientation. This finding is the principal evidence for the existence of a map-and-compass navigational system. Pigeons living in equatorial latitudes utilize the sun compass even under the extreme solar conditions of equinox, achieving angular resolution of about 3 degrees in homing experiments. According to preliminary analyses, the homing pigeons' ephemerides are retarded by several weeks (Ranvaud, Schmidt-Koenig, Ganzhorn et al.).

  15. Photometric Variability in Kepler Target Stars: The Sun Among Stars -- A First Look

    CERN Document Server

    Basri, Gibor; Batalha, Natalie; Gilliland, Ronald L; Jenkins, Jon; Borucki, William J; Koch, David; Caldwell, Doug; Dupree, Andrea K; Latham, David W; Meibom, Soeren; Howell, Steve; Brown, Tim

    2010-01-01

    The Kepler mission provides an exciting opportunity to study the lightcurves of stars with unprecedented precision and continuity of coverage. This is the first look at a large sample of stars with photometric data of a quality that has heretofore been only available for our Sun. It provides the first opportunity to compare the irradiance variations of our Sun to a large cohort of stars ranging from vary similar to rather different stellar properties, at a wide variety of ages. Although Kepler data is in an early phase of maturity, and we only analyze the first month of coverage, it is sufficient to garner the first meaningful measurements of our Sun's variability in the context of a large cohort of main sequence stars in the solar neighborhood. We find that nearly half of the full sample is more active than the active Sun, although most of them are not more than twice as active. The active fraction is closer to a third for the stars most similar to the Sun, and rises to well more than half for stars cooler t...

  16. The third mission

    OpenAIRE

    Francisco José GARCÍA-PEÑALVO

    2016-01-01

    The editorial of this first issue of volume 17, corresponding to 2016, is devoted to the university-business-society relationships that is usually known as Third Mission of the University or the knowledge transfer mission.

  17. Sun-Earth Day: Growth and Impact of NASA E/PO Program

    Science.gov (United States)

    Hawkins, I.; Thieman, J.

    2004-12-01

    Over the past six years, the NASA Sun-Earth Connection Education Forum has sponsored and coordinated education public outreach events to highlight NASA Sun-Earth Connection research and discoveries. Our strategy involves using celestial phenomena, such as total solar eclipses and the Transit of Venus to celebrate Sun-Earth Day, a popular Education and Public Outreach international program. Sun-Earth Day also focuses attention on Equinoxes and Solstices to engage K-12 schools and the general public in space science activities, demonstrations, and interactions with space scientists. In collaboration with partners that include the Exploratorium, Maryland Science Center, NASA Connect, Sun-Earth Connection missions, Ideum, and others, we produce webcasts, other multi-media, and print resources for use by school and informal educators nation-wide. We provide training and professional development to K-12 educators, museum personnel, amateur astronomers, Girl Scout leaders, etc., so they can implement their own outreach programs taking advantage of our resources. A coordinated approach promotes multiple programs occurring each year under a common theme. We will report lessons learned from several years of experience, and strategies for growth and sustainability. We will also share our plans for "Ancient Observatories - Timeless Knowledge" our theme for Sun-Earth Day 2005, which will feature solar alignments at ancient sites that mark the equinoxes and/or solstices. The video and webcast programming will feature several sites including: Chaco Canyon (New Mexico), Hovenweep (Utah), and Chichen Itza (Mexico). Many of these sites present unique opportunities to develop authentic cultural connections to Native Americans, highlighting the importance of the Sun across the ages.

  18. Mission of Librarian

    Directory of Open Access Journals (Sweden)

    Reşit Sarıgül

    2013-11-01

    Full Text Available This article is a review of the book titled “Mission of Librarian” authored by Jose Ortega y Gasset and translated into Turkish by M. Turker Acaroğlu. The book, which is published by  İstanbul Branch of Turkish Librarians’ Association, explains mission, professional mission and mission of librarian in the future. The book also includes an interview with M. Turker Acaroğlu.

  19. Bisphenol-A epoxy resin reinforced and toughened by hyperbranched epoxy resin

    Institute of Scientific and Technical Information of China (English)

    ZHANG Daohong; JIA Demin; HUANG Xianbo

    2007-01-01

    The study on toughening and reinforcing of bisphenol-A epoxy resin is one of important developmental direction in the field.This paper reports a one-pot synthesis of aromatic polyester hyperbranched epoxy resin HTDE-2,an effect of HTDE-2 content on the mechanical and thermal performance of the bisphenol-A (E51)/HTDE-2 hybrid resin in detail.Fourier transform infrared (FT-IR) spectrometer,scanning electronic microscopy (SEM),differential scanning calorimetry (DSC),thermogravimetric analysis (TGA),dynamic mechanical thermal analysis (DMA) and molecular simulation technology are used to study the structure of HTDE-2,performance and toughening and reinforcing mechanism of the HTDE-2/E51 hybrid resin.It has been shown that the content of HTDE-2 has an important effect on the performance of the hybrid resin,and the performance of the HTDE-2/E51 blends has maximum with the increase in HTDE-2 content.The impact strength and fracture toughness of the hybrid resin with 9 wt-% HTDE-2 are almost 3.088 and 1.749 times of E51 performance respectively,furthermore,the tensile and flexural strength can also be enhanced about 20.7% and 14.2%,respectively.The glass transition temperature and thermal degradation temperature,however,are found to decrease to some extent.

  20. Design of Automobile Driveshaft using Carbon/Epoxy and Kevlar/Epoxy Composites

    Directory of Open Access Journals (Sweden)

    R. Srinivasa Moorthy

    2013-10-01

    Full Text Available Use of advanced composites has resulted in remarkable achievements in many fields including aviation, marine and automobile engineering, medicine, prosthetics and sports, in terms of improved fatigue and corrosion resistances, high specific strength and specific modulus and reduction in energy requirements owing to reduction in weight. The aim of this work is to replace the conventional steel driveshaft of automobiles with an appropriate composite driveshaft. The conventional driveshafts are made in two pieces for reducing the bending natural frequency, whereas the composite shafts can be made as single-piece shafts, thus reducing the overall weight. Carbon/Epoxy and Kevlar/Epoxy composites were designed and analysed for their appropriateness in terms of torsional strength, bending natural frequency and torsional buckling by comparing them with the conventional steel driveshaft under the same grounds of design constraints and the best-suited composite was recommended. Light has been thrown upon the aspects like mass saving, number of plies and ply distribution.

  1. Self-Healing Photocurable Epoxy/thiol-ene Systems Using an Aromatic Epoxy Resin

    Directory of Open Access Journals (Sweden)

    Ricardo Acosta Ortiz

    2016-01-01

    Full Text Available A rapid and efficient method to obtain self-healing epoxy resins is discussed. This method is based on the use of a thiol-disulfide oligomer obtained by partial oxidation of a multifunctional thiol using a hypervalent iodine (III compound as oxidant. The oligomer was characterized by Fourier transform infrared spectroscopy (FTIR, Raman and nuclear magnetic resonance spectroscopies, and gel permeation chromatography (GPC. The oligomer was a joint component of the thiol-ene system along with a tetra-allyl-functionalized curing agent. The kinetics of the photopolymerization of diglycidylether of bisphenol A (DGEBA revealed that conversions of the epoxy groups as high as 80% were achieved in only 15 minutes by increasing the concentration of the thiol-ene system in the formulation. The disulfide bonds introduced in the copolymer using the thiol-disulfide oligomer allowed the repairing of the test specimens in as little as 10 minutes when the specimens were heated at 80°C or for 500 minutes at room temperature. The analysis of the mechanical properties using dynamic mechanical analysis (DMA showed that the specimens displayed a healing efficiency up to 111% compared with the unhealed specimens, depending on the amount of polythioethers present in the copolymer.

  2. Threads of Mission Success

    Science.gov (United States)

    Gavin, Thomas R.

    2006-01-01

    This viewgraph presentation reviews the many parts of the JPL mission planning process that the project manager has to work with. Some of them are: NASA & JPL's institutional requirements, the mission systems design requirements, the science interactions, the technical interactions, financial requirements, verification and validation, safety and mission assurance, and independent assessment, review and reporting.

  3. Mission operations management

    Science.gov (United States)

    Rocco, David A.

    1994-01-01

    Redefining the approach and philosophy that operations management uses to define, develop, and implement space missions will be a central element in achieving high efficiency mission operations for the future. The goal of a cost effective space operations program cannot be realized if the attitudes and methodologies we currently employ to plan, develop, and manage space missions do not change. A management philosophy that is in synch with the environment in terms of budget, technology, and science objectives must be developed. Changing our basic perception of mission operations will require a shift in the way we view the mission. This requires a transition from current practices of viewing the mission as a unique end product, to a 'mission development concept' built on the visualization of the end-to-end mission. To achieve this change we must define realistic mission success criteria and develop pragmatic approaches to achieve our goals. Custom mission development for all but the largest and most unique programs is not practical in the current budget environment, and we simply do not have the resources to implement all of our planned science programs. We need to shift our management focus to allow us the opportunity make use of methodologies and approaches which are based on common building blocks that can be utilized in the space, ground, and mission unique segments of all missions.

  4. Toughening Mechanisms in Silica-Filled Epoxy Nanocomposites

    Science.gov (United States)

    Patel, Binay S.

    Epoxies are widely used as underfill resins throughout the microelectronics industry to mechanically couple and protect various components of flip-chip assemblies. Generally rigid materials largely surround underfill resins. Improving the mechanical and thermal properties of epoxy resins to better match those of their rigid counterparts can help extend the service lifetime of flip-chip assemblies. Recently, researchers have demonstrated that silica nanoparticles are effective toughening agents for lightly-crosslinked epoxies. Improvements in the fracture toughness of silica-filled epoxy nanocomposites have primarily been attributed to two toughening mechanisms: particle debonding with subsequent void growth and matrix shear banding. Various attempts have been made to model the contribution of these toughening mechanisms to the overall fracture energy observed in silica-filled epoxy nanocomposites. However, disparities still exist between experimental and modeled fracture energy results. In this dissertation, the thermal, rheological and mechanical behavior of eight different types of silica-filled epoxy nanocomposites was investigated. Each nanocomposite consisted of up to 10 vol% of silica nanoparticles with particle sizes ranging from 20 nm to 200 nm, with a variety of surface treatments and particle structures. Fractographical analysis was conducted with new experimental approaches in order to accurately identify morphological evidence for each proposed toughening mechanism. Overall, three major insights into the fracture behavior of real world silica-filled epoxy nanocomposites were established. First, microcracking was observed as an essential toughening mechanism in silica-filled epoxy nanocomposites. Microcracking was observed on the surface and subsurface of fractured samples in each type of silica-filled epoxy nanocomposite. The additional toughening contribution of microcracking to overall fracture energy yielded excellent agreement between experimental

  5. Epoxy nanocomposites based on high temperature pyridinium-modified clays.

    Science.gov (United States)

    Zhang, Qingxin; Naito, Kimiyoshi; Qi, Ben; Kagawa, Yutaka

    2009-01-01

    Polymer/clay nanocomposites are generally fabricated by thermal curing or melt compounding at elevated temperatures, however the thermal stability of common alkyl ammonium treated clays is poor and decomposition occurs inevitably during high temperature processing. In this study, we modified clays with an aromatic pyridinium salt. Thermogravimetric analysis (TGA) showed that the onset degradation temperature (Td(onset)) and maximum decomposition temperature (Td(max)) of the pyridinium treatment clays was up to 310 and 457 degrees C respectively implying high thermal stability. The thermal decomposition behaviour of the pyridinium modified clays was discussed. A series of epoxy/clay nanocomposites were synthesized using a diglycidyl ether of bisphenol A (DGEBA) epoxy and diethyltoluene diamine (DETDA). The morphology of epoxy/clay nanocomposites was characterized with wide angle X-ray diffraction (WAXD) and transmission electron microscope (TEM), and intercalated structures were observed. The storage modulus of epoxy was increased but glass transition temperature was decreased with clay incorporation. The effects of clays on glass transition temperature (Tg) of epoxy were also discussed.

  6. Preparation and properties of lignin-epoxy resin composite

    Directory of Open Access Journals (Sweden)

    Quanfu Yin

    2012-11-01

    Full Text Available A cross-linked biomass-polymer composite with a lignin content of up to 60% was prepared by blending lignin with an epoxy resin and polyamine using a hot press molding process. The characteristics of the curing reaction of lignin with epoxy resin were studied using DSC and FTIR analysis. The effect of molding temperature and molding pressure on the mechanical properties and microstructure of the lignin/epoxy resin composite was also studied by SEM, DMA, and TG analyses. The results showed that the epoxy resin can be cured by lignin, and the curing temperature for the blends can be reduced by the introduction of a polyamine cure agent. The properties of the composite, such as bending strength, impact strength, glass-transition temperature, and thermal stability, were evidently influenced by the molding process. A good interfacial combination was formed between lignin and epoxy resin. Increasing the molding temperature and pressure proved beneficial to achieve a better interfacial combination for the composite, and the degree of ductile fracture was increased in the fracture surface of the composite.

  7. SYNTHESIS AND CHARACTERIZATION OF KRAFT LIGNIN-BASED EPOXY RESINS

    Directory of Open Access Journals (Sweden)

    Nour Eddine El Mansouri

    2011-05-01

    Full Text Available Epoxidization is an interesting way to develop a new application of lignin and therefore to improve its application potential. In this work, kraft lignin-based epoxy resins were obtained by the epoxidization reaction, using the kraft lignin recovered directly from pulping liquor and modified by a methylolation reaction. The methylolated lignins were obtained by the reaction of original kraft lignin with formaldehyde and glyoxal, which is a less volatile and less toxic aldehyde. 1H-NMR spectroscopy showed that methylolated kraft lignin has more hydroxymethyl groups than glyoxalated kraft lignin. For the epoxidization reaction we studied the influence of the lignin:NaOH (w/w ratio, temperature, and time of the reaction on the properties of the prepared epoxidized lignins. The structures of lignin-based epoxy resins were followed by epoxy index test and FTIR spectroscopy. Optimal conditions were obtained for lignin-based epoxy resin produced at lignin/NaOH = 1/3 at 70 ºC for 3h. Thermogravimetry analysis (TGA revealed that the epoxidization enhances the thermal stability of lignins and may allow a wider temperature range for applications with lignin epoxy-PF blends.

  8. New Thermal and Microbial Resistant Metal-Containing Epoxy Polymers

    Directory of Open Access Journals (Sweden)

    Tansir Ahamad

    2010-01-01

    Full Text Available A series of metal-containing epoxy polymers have been synthesized by the condensation of epichlorohydrin (1-chloro-2,3-epoxy propane with Schiff base metal complexes in alkaline medium. Schiff base was initially prepared by the reaction of 2,6 dihydroxy 1-napthaldehyde and o-phenylenediamine in 1  :  2 molar ratio and then with metal acetate. All the synthesized compounds were characterized by elemental, spectral, and thermal analysis. The physicochemical properties, viz., epoxy value, hydroxyl content, and chlorine content [mol/100 g] were measured by standard procedures. The antimicrobial activities of these metal-containing epoxy polymers were carried out by using minimum inhibitory concentration (MIC and minimum bactericidal concentration (MBC methods against S. aureus, B. subtilis (Gram-positive bacteria, and E. coli, P. aeruginosa (Gram-negative bacteria. It was found that the ECu(II showed higher antibacterial activity than other metal-chelated epoxy resin while EMn(II exhibited reduced antibacterial activity against all bacteria.

  9. Morphological and Thermal Properties of Cellulose Nanofibrils Reinforced Epoxy Nanocomposites

    Directory of Open Access Journals (Sweden)

    Deniz Aydemir

    2015-04-01

    Full Text Available Epoxy resins have gained attention as important adhesives because they are structurally stable, inert to most chemicals, and highly resistant to oxidation. Different particles can be added to adhesives to improve their properties. In this study, cellulose nanofibrils (CNFs, which have superior mechanical properties, were used as the reinforcing agent. Cellulose nanofi brils were added to epoxy in quantities of 1 %, 2 % and 3 % by weight to prepare nanocomposites. Morphological characterization of the composites was done with scanning electron microscopy (SEM. Thermal properties of the nanocomposites were investigated with Thermogravimetric Analyzer (TGA/DTG and Differential Scanning Calorimeter (DSC. SEM images showed that the cellulose nanofibrils were dispersed partially homogenous throughout the epoxy matrix for 1 % CNF. However, it was observed that the cellulose nanofibrils were aggregated (especially for 2 and 3 % CNFs in some parts of the SEM images, and the ratios of the aggregated parts increased as the loading rate of the cellulose nanofi brils increased. The TGA curve showed that DTG and decomposition temperature of pure epoxy was higher than that of the nanocomposites. The DSC curve showed that the glass transition temperature (Tg value of pure epoxy was found to be similar with Tg of the nanocomposites.

  10. Fiber-Reinforced Reactive Nano-Epoxy Composites

    Science.gov (United States)

    Zhong, Wei-Hong

    2011-01-01

    An ultra-high-molecular-weight polyethylene/ matrix interface based on the fabrication of a reactive nano-epoxy matrix with lower surface energy has been improved. Enhanced mechanical properties versus pure epoxy on a three-point bend test include: strength (25 percent), modulus (20 percent), and toughness (30 percent). Increased thermal properties include higher Tg (glass transition temperature) and stable CTE (coefficient of thermal expansion). Improved processability for manufacturing composites includes faster wetting rates on macro-fiber surfaces, lower viscosity, better resin infusion rates, and improved rheological properties. Improved interfacial adhesion properties with Spectra fibers by pullout tests include initial debonding force of 35 percent, a maximum pullout force of 25 percent, and energy to debond at 65 percent. Improved mechanical properties of Spectra fiber composites (tensile) aging resistance properties include hygrothermal effects. With this innovation, high-performance composites have been created, including carbon fibers/nano-epoxy, glass fibers/nano-epoxy, aramid fibers/ nano-epoxy, and ultra-high-molecularweight polyethylene fiber (UHMWPE).

  11. Liquid crystalline epoxy nanocomposite material for dental application.

    Science.gov (United States)

    Tai, Yun-Yuan; Hsu, Sheng-Hao; Chen, Rung-Shu; Su, Wei-Fang; Chen, Min-Huey

    2015-01-01

    Novel liquid crystalline epoxy nanocomposites, which exhibit reduced polymerization shrinkage and effectively bond to tooth structures, can be applied in esthetic dentistry, including core and post systems, direct and indirect restorations, and dental brackets. The purposes of this study were to investigate the properties of liquid crystalline epoxy nanocomposites including biocompatibility, microhardness, and frictional forces of bracket-like blocks with different filler contents for further clinical applications. In this study, we evaluated liquid crystalline epoxy nanocomposite materials that exhibited various filler contents, by assessing their cell activity performance using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and their microhardness with or without thermocycling. We also evaluated the frictional force between bracket-like duplicates and commercially available esthetic bracket systems using Instron 5566. The liquid crystalline epoxy nanocomposite materials showed good biocompatibility. The materials having high filler content demonstrated greater microhardness compared with commercially available bracket materials, before and after the thermocycling treatment. Thus, manufacturing processes are important to reduce frictional force experienced by orthodontic brackets. The microhardness of the bracket-like blocks made by our new material is superior to the commercially available brackets, even after thermocycling. Our results indicate that the evaluated liquid crystalline epoxy nanocomposite materials are of an appropriate quality for application in dental core and post systems and in various restorations. By applying technology to refine manufacturing processes, these new materials could also be used to fabricate esthetic brackets for orthodontic treatment. Copyright © 2014. Published by Elsevier B.V.

  12. Homogeneous Liquid Phase Transfer of Graphene Oxide into Epoxy Resins.

    Science.gov (United States)

    Amirova, Lyaysan; Surnova, Albina; Balkaev, Dinar; Musin, Delus; Amirov, Rustem; Dimiev, Ayrat M

    2017-04-05

    The quality of polymer composite materials depends on the distribution of the filler in the polymer matrix. Due to the presence of the oxygen functional groups, graphene oxide (GO) has a strong affinity to epoxy resins, providing potential opportunity for the uniform distribution of GO sheets in the matrix. Another advantage of GO over its nonoxidized counterpart is its ability to exfoliate to single-atomic-layer sheets in water and in some organic solvents. However, these advantages of GO have not yet been fully realized due to the lack of the methods efficiently introducing GO into the epoxy resin. Here we develop a novel homogeneous liquid phase transfer method that affords uniform distribution, and fully exfoliated condition of GO in the polymer matrix. The most pronounced alteration of properties of the cured composites is registered at the 0.10%-0.15% GO content. Addition of as little as 0.10% GO leads to the increase of the Young's modulus by 48%. Moreover, we demonstrate successful introduction of GO into the epoxy matrix containing an active diluent-modifier; this opens new venues for fabrication of improved GO-epoxy-modifier composites with a broad range of predesigned properties. The experiments done on reproducing the two literature methods, using alternative GO introduction techniques, lead to either decrease or insignificant increase of the Young's modulus of the resulting GO-epoxy composites.

  13. ETV Program Report: Coatings for Wastewater Collection Systems - Standard Cement Materials, Epoxy Coating 4553

    Science.gov (United States)

    The Standard Cement Materials, Inc. Standard Epoxy Coating 4553™ (SEC 4553) epoxy coating used for wastewater collection system rehabilitation was evaluated by EPA’s Environmental Technology Verification Program under laboratory conditions at the Center for Innovative Grouting Ma...

  14. ETV Program Report: Coatings for Wastewater Collection Systems - Standard Cement Materials, Epoxy Coating 4553

    Science.gov (United States)

    The Standard Cement Materials, Inc. Standard Epoxy Coating 4553™ (SEC 4553) epoxy coating used for wastewater collection system rehabilitation was evaluated by EPA’s Environmental Technology Verification Program under laboratory conditions at the Center for Innovative Grouting Ma...

  15. Engineering the magnetic properties of zigzag graphene nanoribbon by epoxy chains

    Science.gov (United States)

    Pu, H. H.; Rhim, S. H.; Gajdardziksa-Josifovska, M.; Hirschmugl, C. J.; Weinert, M.; Chen, J. H.

    2017-08-01

    The magnetic properties of zigzag graphene nanoribbon (ZGNR) oxidized by either two single epoxy or one epoxy pair chains were investigated here. The results show that the epoxy pair chain essentially produces finite spin moment for both the antiferromagnetic (AFM) and the ferromagnetic (FM) coupling between the ribbon edges, while the two single epoxy chains oxidized ZGNR and pure ZGNR show the trivial moment for the AFM coupling. The total spin moment has a weak dependence on the position of single epoxy and epoxy pair chains inside the ZGNR and on the width of ZGNR. In addition, the ZGNR oxidized by one epoxy pair chain transitions from a half metal to a semiconductor via tuning the Fermi level when the chain shifts inwards from the ribbon edge. Our results suggest the potential for designing graphene-based spintronics by introducing epoxy pair chains.

  16. Mechanical properties of uniaxial natural fabric Grewia tilifolia reinforced epoxy based composites: Effects of chemical treatment

    CSIR Research Space (South Africa)

    Jayaramudu, J

    2014-07-01

    Full Text Available The effects of chemical treatment on the mechanical, morphological, and chemical resistance properties of uniaxial natural fabrics, Grewia tilifolia/epoxy composites, were studied. In order to enhance the interfacial bonding between the epoxy matrix...

  17. A new double layer epoxy coating for corrosion protection of Petroleum Equipments

    Directory of Open Access Journals (Sweden)

    Maher A. El Sockarya

    2014-11-01

    Full Text Available Homogeneous epoxy coating containing polymer nanocomposite (PNC was successfully synthesized and applied on carbon steel substrates by room temperature curing of fully mixed epoxy slurry. (PNC containing both ZNO nanoparticles and epoxy hyper branched polymer (EHBP, a new double layer thin film which comprises ZNO-epoxy as a primer coat and ZNO-EHBP-epoxy as a top coat offers better corrosion protection compared to the purely inorganic ZNO-epoxy coating and hybrid ZNO-EHBP-epoxy coating. Chemical structures of synthesized compounds were confirmed by FTIR, H1NMR spectroscopy and GPC. The surface morphology and phase structure of the produced Zno nanoparticles were characterized by scanning electron microscopy SEM, transmission electron microscopy TEM and X-ray diffraction. Chemical resistance of theses coatings to NaOH and HCL was investigated. The effect of incorporating polymer nanocomposite and new double layer coating on corrosion resistance of epoxy coated steel was investigated by salt spray test.

  18. Graphite/Ultra-High Modulus Polyethylene Hybrid Fiber Composites with Epoxy and Polyethylene Matrices for Cosmic Radiation Shielding

    Science.gov (United States)

    2003-01-01

    One of the most significant technical challenges in long-duration space missions is that of protecting the crew from harmful radiation. Protection against such radiation on a manned Mars mission will be of vital importance both during transit and while on the surface of the planet. The development of multifunctional materials that serve as integral structural members of the space vehicle and provide the necessary radiation shielding for the crew would be both mission enabling and cost effective. Additionally, combining shielding and structure could reduce total vehicle mass. Hybrid laminated composite materials having both ultramodulus polyethylene (PE) and graphite fibers in epoxy and PE matrices could meet such mission requirements. PE fibers have excellent physical properties, including the highest specific strength of any known fiber. Moreover, the high hydrogen (H) content of polyethylene makes the material an excellent shielding material for cosmic radiation. When such materials are incorporated into an epoxy or PE matrix a very effective shielding material is expected. Boron (B) may be added to the matrix resin or used as a coating to further increase the shielding effectiveness due to B s ability to slow thermal neutrons. These materials may also serve as micrometeorites shields due to PE s high impact energy absorption properties. It should be noted that such materials can be fabricated by existing equipment and methods. It is the objective of this work therefore to: (a) perform preliminary analysis of the radiation transport within these materials; (b) fabricate panels for mechanical property testing before and after radiation exposure. Preliminary determination on the effectiveness of the combinations of material components on both shielding and structural efficiency will be made.

  19. Graphite/Ultra-High Modulus Polyethylene Hybrid Fiber Composites with Epoxy and Polyethylene Matrices for Cosmic Radiation Shielding

    Science.gov (United States)

    2003-01-01

    One of the most significant technical challenges in long-duration space missions is that of protecting the crew from harmful radiation. Protection against such radiation on a manned Mars mission will be of vital importance both during transit and while on the surface of the planet. The development of multifunctional materials that serve as integral structural members of the space vehicle and provide the necessary radiation shielding for the crew would be both mission enabling and cost effective. Additionally, combining shielding and structure could reduce total vehicle mass. Hybrid laminated composite materials having both ultramodulus polyethylene (PE) and graphite fibers in epoxy and PE matrices could meet such mission requirements. PE fibers have excellent physical properties, including the highest specific strength of any known fiber. Moreover, the high hydrogen (H) content of polyethylene makes the material an excellent shielding material for cosmic radiation. When such materials are incorporated into an epoxy or PE matrix a very effective shielding material is expected. Boron (B) may be added to the matrix resin or used as a coating to further increase the shielding effectiveness due to B s ability to slow thermal neutrons. These materials may also serve as micrometeorites shields due to PE s high impact energy absorption properties. It should be noted that such materials can be fabricated by existing equipment and methods. It is the objective of this work therefore to: (a) perform preliminary analysis of the radiation transport within these materials; (b) fabricate panels for mechanical property testing before and after radiation exposure. Preliminary determination on the effectiveness of the combinations of material components on both shielding and structural efficiency will be made.

  20. New Views of the Sun: STEREO and Hinode

    Science.gov (United States)

    Luhmann, Janet G.; Tsuneta, Saku; Bougeret, J.-L.; Galvin, Antoinette; Howard, R. A.; Kaiser, Michael; Thompson, W. T.

    The twin-spacecraft STEREO mission has now been in orbit for 1.5 years. Although the main scientific objective of STEREO is the origin and evolution of Coronal Mass Ejections (CMEs) and their heliospheric consequences, the slow decline of the previous solar cycle has provided an extraordinary opportunity for close scrutiny of the quiet corona and solar wind, including suprathermal and energetic particles. However, STEREO has also captured a few late cycle CMEs that have given us a taste of the observations and analyses to come. Images from the SECCHI investigation afforded by STEREO's separated perspectives and the heliospheric imager have already allowed us to visibly witness the origins of the slow solar wind and the Sun-to-1 AU transit of ICMEs. The SWAVES investigation has monitored the transit of interplanetary shocks in 3D while the PLASTIC and IMPACT in-situ measurements provide the 'ground truth' of what is remotely sensed. New prospects for space weather forecasting have been demonstrated with the STEREO behind spacecraft, a successful proof-of-concept test for future space weather mission designs. The data sets for the STEREO investigations are openly available through a STEREO Science Center web interface that also provides supporting information for potential users from all communities. Comet observers and astronomers, interplanetary dust researchers and planetary scientists have already made use of this resource. The potential for detailed Sun-to-Earth CME/ICME interpretations with sophisticated modeling efforts are an upcoming STEREO-Hinode partnering activity whose success we can only anticipate at this time. Since its launch in September 2006, Hinode has sent back solar images of unprecedented clarity every day. The primary purpose of this mission is a systems approach to understanding the generation, transport and ultimate dissipation of solar magnetic fields with a well-coordinated set of advanced telescopes. Hinode is equipped with three

  1. STUDY ON COPOLYMER EPOXY RESIN MATRIX WITHOUT SHRINKAGE PART I VOLUME CHANGE DURING CURE PROCESSES

    Institute of Scientific and Technical Information of China (English)

    HE Pingsheng; ZHOU Zhiqiang; WANG Gengchao; PAN Caiyuan; WU Renjie

    1988-01-01

    The volume change of the copolymer epoxy resins can be controlled by copolymerizing epoxy resin E51 with 3,9-di (5-norbornene-2, 2)-1, 5, 7, 11-tetraoxaspiro [5, 5] undecane (NSOC). During curing,the volume changes of copolymer epoxy resins with various amounts of NSOC were measured with a dilatometer. Cure process does not produce volume change when epoxy resin E51: NSOC is 5.88: 1 in equivalent.

  2. STUDY ON THE EPOXY RESIN TOUGHENED BY HYDROXY-TERMINATED BUTADIENE-ACRYLONITRILE COPOLYMER

    Institute of Scientific and Technical Information of China (English)

    HAN Xiaozu; LI Shaoying; ZHANG Qingyu

    1990-01-01

    Toughened epoxy resin with excellent properties was obtained by adding organic acid anhydride curing agent and hydroxy-terminated butadiene-acrylonitrile copolymer (HTBN), which is cheaper than CTBN. The anhydride reacts with both epoxy groups on epoxy resin and hydroxyl groups on HTBN. As a result the soft long chains of HTBN and the rigid chain of epoxy resin form one network, giving the resin toughness. Two-phase structure of the toughened resin was observed by SEM and TEM.

  3. Modification of epoxy resins with thermoplastic segmented polycarbonate-based polyurethanes

    OpenAIRE

    Pavličević Jelena; Jovičić Mirjana; Simendić Vesna; Bera Oskar; Radičević Radmila; Špírková Milena

    2014-01-01

    In this work, epoxy hybrid materials were synthesized by addition of thermoplastic segmented aliphatic polyurethanes with good elastic properties. The modified epoxy samples were obtained by curing of previously homogenized mixture of prepared polyurethane melts, epoxy resin and crosslinking agent Jeffamine D-2000. The influence of different weight content of polyurethanes (5, 10 and 15 wt. % compared to pure epoxy resin) as well the influence of different ...

  4. PREPARATION, CHARACTERIZATION AND THERMAL BEHAVIOR OF ALKYL SUBSTITUTED PHENOLIC EPOXY RESIN

    OpenAIRE

    Jyoti Chaudhary*, Supriya Dadhich, Giriraj Tailor

    2017-01-01

    The present article deals with the synthesis of phenolic epoxy resin by the reaction of phenolic resin and epichlorohydrin. The synthesis of phenolic resin was carried out by using p-ethylphenol, formaldehyde and naphthol. The structures of phenolic and epoxy resins were confirmed by spectroscopic analysis. The synthesized epoxy resin showed solubility in polar solvents like DMF, dioxane, acetone, DMSO, THF, ethyl acetate, and chloroform. Thermal characterization of epoxy resin was monitored ...

  5. The Solar Dynamics Observatory: Your eye on the Sun

    Science.gov (United States)

    Pesnell, William

    The Solar Dynamics Observatory (SDO) was launched on February 11, 2010 into partly cloudy skies over Cape Canaveral, Florida. SDO has since moved into a 28 degree inclined geosyn-chronous orbit over the longitude of the ground station in New Mexico. SDO is the first Space Weather Mission in NASA's Living With a Star Program. SDO's main goal is to understand and predict those solar variations that influence life on Earth and our technological systems. The SDO science investigations will determine how the Sun's magnetic field is generated and structured, how this stored magnetic energy is released into the heliosphere and geospace as the solar wind, energetic particles, and variations in the solar irradiance. The SDO mission consists of three scientific investigations (AIA, EVE, and HMI), a spacecraft bus, and a ded-icated Ka-band ground station to handle the 150 Mbps data flow. Science teams at LMSAL, LASP, and Stanford are responsible for processing, analyzing, distributing, and archiving the science data. We will talk about the building of SDO, its launch, and the data and science it will provide to NASA.

  6. Degradation of epoxy coatings under gamma irradiation

    Science.gov (United States)

    Djouani, F.; Zahra, Y.; Fayolle, B.; Kuntz, M.; Verdu, J.

    2013-01-01

    Epoxy networks based on Diglycidyl ether of bisphenol A (DGEBA) and cured with Jeffamine® (POPA) or polyamidoamine (PAA) were gamma irradiated at 25 °C in air. Dose rates of 50, 200 or 2000 Gy h-1 for doses up 100 kGy were used. Structural changes were monitored by IR spectrophotometry, DSC and sol-gel analysis. Both networks display some common features: for I≥200 Gy h-1, reaction products grow proportionally to time and the rate is a decreasing function of dose rate. The simplest explanation is that peroxy radicals are the main precursors of these products (in the dose rate domain under study), through a unimolecular rearrangement of which an hypothetical mechanism is proposed. DGEBA-POPA are more reactive then DGEBA-PAA networks (according to IR criteria), that can be attributed to the high reactivity of tertiary CH bands in polyoxypropylene segments. The oxidation of these sites leads to methyl ketones. A simple kinetic model in which methyl ketones result from rearrangements of tertiary peroxyls and from tertiary alkoxyls was proposed. It leads to an expression of the radiochemical yield of methyl ketones (G(MK)) of the form G(MK)=a+bI where a and b are parameters depending of elementary rate constants. Experimental G(MK) values are reasonably well fitted by this equation. In DGEBA-PAA networks, a wide variety of oxidation products, among which amides predominate, can be observed. In these networks, chain scissions predominate over crosslinking, whereas a slight predominance of crosslinking was observed, at least for the lowest dose rate, in DGEBA-POPA.

  7. Acrylate Copolymers as Impact Modiifer for Epoxy Resin

    Institute of Scientific and Technical Information of China (English)

    WANG Tao; WANG Jun; CHEN Wei; DUAN Huajun; YANG Shuang; CHEN Xi; ZHANG Bin

    2015-01-01

    P(BA-GMA) (PBG), having various molecular weights, was synthesized by in situ polymerization of butyl acrylate (BA) and glycidyl methacrylate (GMA), and further used as a modifier to improve the comprehensive properties of the epoxy curing system. The copolymers were characterized by gel permeation chromatography (GPC). The effects of various molecular weights of copolymers on the mechanical properties, thermal performance, and phase behavior of the curing system were carefully evaluated. The experimental results of differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) showed that glass transition temperature decreased and the tan δ peak shifted to a lower temperature with decreasing molecular weight of copolymer. Mechanical properties analysis of curing films showed that the impact strength and fracture toughness increased significantly upon the addition of PBG, indicating good toughness of the modified epoxy resins. From scanning electron microscopy (SEM) studies of the fracture surfaces of ER/PBG systems, the fracture behavior of epoxy matrix was changed from brittleness to toughness.

  8. ensile and Compressive Properties of Kaolin Rienforced Epoxy

    Directory of Open Access Journals (Sweden)

    Jabbar Hussein Mohmmed

    2015-09-01

    Full Text Available The toughening of epoxy resins with the addition of organic or inorganic compounds is of great interest nowadays, considering their large scale of applications. In the present work, composites of epoxy are synthesized with kaolin particles having different particle sizes as reinforcement. Composites of epoxy with varying concentration (0 to 40 weight % of kaolin was prepared by using hand lay method. The variation of mechanical properties such as modulus of elasticity, yield, tensile, and compressive strength with filler content was evaluated. The composite showed improved modulus of elasticity and compressive properties on addition of filler. In contrast, the tensile and yield strength of the composites decreases with rising kaolin content. It is also observed that mechanical properties increase with decrease in particle size in all cases.

  9. On sample preparation and dielectric breakdown in nanostructured epoxy resins

    Energy Technology Data Exchange (ETDEWEB)

    Reading, M; Xu, Z; Lewin, P L; Vaughan, A S, E-mail: asv@ecs.soton.ac.uk [Tony Davies High Voltage Laboratory, University of Southampton (United Kingdom)

    2011-08-12

    There are many methods available to achieve a good dispersion of fillers within a polymeric matrix. This investigation considered several methods of dispersing three chosen fillers within an epoxy resin; the same processes were also performed on unfilled materials to investigate any effects they may have on the host material. For this investigation, the epoxy system (EP) was combined with sodium montmorillonite (MMT), micrometric silicon dioxide (SD) or nanometric silicon dioxide (NSD) as fillers. The effect of the different sample preparation routes on breakdown behaviour was then evaluated. While more thorough mixing protocols were found to lead to improved breakdown behaviour in the case of the various filled systems, surprisingly, an entirely equivalent form of behaviour was also seen in the unfilled epoxy. The influence of changes in sample geometry on the breakdown strength was established.

  10. Dielectric properties of inorganic fillers filled epoxy thin film

    Energy Technology Data Exchange (ETDEWEB)

    Norshamira, A., E-mail: myra.arshad@gmail.com; Mariatti, M., E-mail: mariatti@usm.my [School of Materials and Mineral Resources Engineering, Engineering Campus, Universiti Sains Malaysia, 14300 Nibong Tebal, Pulau Pinang (Malaysia)

    2015-07-22

    The demand on the small size and high performance electronics has driven changes in the electronic packaging requirements from discrete capacitor to embedded capacitor. Embedded capacitor can improve electrical performance compared with discrete capacitor. This study aimed to achieve high dielectric of epoxy thin film composite that were targeted for application as embedded capacitor. In this study, inorganic fillers such as Calcium Copper Titanate (CCTO), Iron(III) Oxide (Fe{sub 2}O{sub 3}) and Titanium Dioxide (TiO{sub 2}) were loaded in epoxy system at 5 and 20vol%. Morphology and dielectric properties were investigated to identify the effect of fillers loading and types of fillers on the properties of epoxy thin film composite. Based on the study, CCTO with 20vol% loading was found to have good dielectric properties compared to other type of fillers.

  11. Synthesis and characterization of rubbery epoxy/organoclay hectorite nanocomposites

    Directory of Open Access Journals (Sweden)

    2007-12-01

    Full Text Available The present research investigates the morphology, the mechanical, and the viscoelastic properties of rubbery epoxy/clay nanocomposites synthesized by in situ polymerisation of a prepolymer diglycidyl ether of bisphenol-A crosslinked with an aliphatic diamine based on a polyoxypropylene backbone. The inorganic phase was hectorite, exchanged with octadecylammonium ions in order to give organophilic properties to the phyllosilicate. An ultrasonicator was used to disperse the silicate clay layer into epoxy-amine matrix. The morphology of epoxy-hectorite nanocomposites examined by transmission electron microscopy (TEM showed that mixed delamination or intercalation or microdispersion could occur depending on type of organoclay. Moreover, the mechanical and viscoelastic properties were found to be improved with only the treated hectorite.

  12. DEGRADATION OF MAGNET EPOXY AT NSLS X-RAY RING.

    Energy Technology Data Exchange (ETDEWEB)

    HU,J.P.; ZHONG,Z.; HAAS,E.; HULBERT,S.; HUBBARD,R.

    2004-05-24

    Epoxy resin degradation was analyzed for NSLS X-ring magnets after two decades of 2.58-2.8 GeV continuous electron-beam operation, based on results obtained from thermoluminescent dosimeters irradiated along the NSLS ring and epoxy samples irradiated at the beamline target location. A Monte Carlo-based particle transport code, MCNP, was utilized to verify the dose from synchrotron radiation distributed along the axial- and transverse-direction in a ring model, which simulates the geometry of a ring quadrupole magnet and its central vacuum chamber downstream of the bending-magnet photon ports. The actual life expectancy of thoroughly vacuum baked-and-cured epoxy resin was estimated from radiation tests on similar polymeric materials using a radiation source developed for electrical insulation and mechanical structure studies.

  13. Reinforcement of Epoxies Using Single Walled Carbon Nanotubes

    Science.gov (United States)

    Krishnamoorti, Ramanan; Sharma, Jitendra; Chatterjee, Tirtha

    2008-03-01

    The reinforcement of bisphenol-A and bisphenol-F epoxies using single walled carbon nanotubes has been approached experimentally by understanding the nature of interactions between the matrices and nanotubes. Unassisted dispersions of single walled carbon nanotubes in epoxies were studied by a combination of radiation scattering (elastic small angle scattering and inelastic scattering), DSC based glass transition determination, melt rheology and solid-state mechanical testing in order to understand and correlate changes in local and global dynamics to the tailoring of composite mechanical properties. Significant changes in the glass transition temperature of the matrix can successfully account for changes in the viscoelastic properties of the epoxy dispersions for concentrations below the percolation threshold, while above the percolation threshold the network superstructure formed by the nanotubes controls the viscoelastic properties.

  14. Epoxy-silicate nanocomposites: Cure monitoring and characterization

    Energy Technology Data Exchange (ETDEWEB)

    Hussain, Farzana [Aerospace Manufacturing Technology Center (AMTC), Institute for Aerospace Research (IAR), National Research Council Canada - NRC, Montreal, QC (Canada)]. E-mail: farzssain@gmail.com; Chen, Jihua [Aerospace Manufacturing Technology Center (AMTC), Institute for Aerospace Research (IAR), National Research Council Canada -NRC, Montreal, QC (Canada); Hojjati, Mehdi [Aerospace Manufacturing Technology Center (AMTC), Institute for Aerospace Research (IAR), National Research Council Canada - NRC, Montreal, QC (Canada)

    2007-02-15

    Epoxy-clay nanocomposites were prepared with organically modified layered clay with varying clay contents (1-8 wt.%). Neat resin and nanocomposite were characterized using different techniques. At first, the effect of nanoclay concentration on the cure behaviour was investigated using an on-line dielectric cure monitoring technique. Differential scanning calorimetry (DSC) was used to verify the dielectric measurement results. Furthermore, mechanical and thermal properties were studied using tensile test and Dynamic Mechanical Analysis (DMA), respectively. Experimental results showed that properties of the epoxy were changed evidently because of the nanoclay loading. The tensile modulus of the nanocomposites increased by 47%, however, no improvement in tensile strength and glass transition temperature (T {sub g}) was observed. Fracture surface of the tensile samples were analyzed by Scanning Electron Microscope (SEM). The nanocomposites structures were characterized with Wide Angle X-Ray Diffraction (WAXD) and Transmission Electron Microscopy (TEM), which revealed the intercalated morphology of clay layers in the epoxy resin systems.

  15. Formation of a metal/epoxy resin interface

    Energy Technology Data Exchange (ETDEWEB)

    Kanzow, J.; Horn, P. Schulze; Kirschmann, M.; Zaporojtchenko, V.; Dolgner, K.; Faupel, F.; Wehlack, C.; Possart, W

    2005-01-15

    Interfaces between cross-linked polymers and metals play a significant role in fields like splicing and coating, metallization of plastics, microelectronics, micro system technology and nanotechnology. In this paper, we present investigations on the interface formation due to metallization (Au, Ag, Cu and Al) by evapouration of the highly cured epoxy resin system diglycidilether of bisphenol a (DGEBA)-diethylene triamine (DETA) with the focus on the structure formation at the interface. A combination of X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), atomic force microscopy (AFM) and a radiotracer technique was used to analyze the metal/epoxy interface. While a strong metal/epoxy interaction was found for Al, the noble metals Au, Ag and Cu grow in a Volmer-Weber mode due to an interplay of surface diffusion and metal cluster growth. Nevertheless, polymer bulk diffusion of these metals is negligible.

  16. Multiple welding of long fiber epoxy vitrimer composites.

    Science.gov (United States)

    Chabert, Erwan; Vial, Jérôme; Cauchois, Jean-Pierre; Mihaluta, Marius; Tournilhac, François

    2016-05-25

    Vitrimers appear as a new class of polymers that exhibit mechanical strength and are insoluble even at high temperatures, like thermosets, and yet, like thermoplastics, they are heat processable, recyclable and weldable. The question arises whether this welding property is maintained in composite materials made of more than 50 vol% of reinforcing fibers. In this paper, we quantitatively analyze the bond strength of epoxy vitrimer-based composite plates made by resin transfer molding and compare them to their non-vitrimer counterparts made of a standard thermoset epoxy. It is demonstrated that only epoxy vitrimer samples show substantial bond strength and the ability to be repeatedly welded thanks to the exchange reactions, which promote improved surface conformity and chemical bonding between the adherands at the joint interface. This opens the way towards joining composite parts without adhesives nor mechanical fasteners.

  17. Thermal Measurements on Polymeric Epoxy-Expandable Graphite Material

    Directory of Open Access Journals (Sweden)

    Joseph Asante

    2016-01-01

    Full Text Available Combustion measurements, such as heat release rate, critical flux, time-to-ignition, ignition temperature, thermal inertia, and kinematics—activation energy as well as preexponential factor—on epoxy polymer (Prime™ 20LV with expandable graphite (EG inorganic filler of different weight percentage composites, are conducted using the Dual Cone Calorimeter, the thermogravimetric analysis (TGA, and Linseis (Germany THB100 Transient Hot Bridge thermal conductivity analyser. The results indicate that increasing the amount of EG in polymer composite leads to reduction in the critical flux, the time-to-ignition, the ignition temperature, the thermal inertia, the average thermal conductivity, and the activation energy (from 159.1 ± 2.3 to 145.9 ± 3.1 kJ/mol for neat epoxy to 3 wt.% EG-epoxy of the composite samples. There is, however, an increase in the heat of gasification with increasing EG content.

  18. Mechanical properties of rice husk flour reinforced epoxy biocomposite

    Directory of Open Access Journals (Sweden)

    Neeraj Bisht

    2015-06-01

    Full Text Available A bio-composite reinforced with rice husk flour in epoxy resin has been developed. The effect of fibre treatment and weight percentage of rice husk on the mechanical properties was studied and compared with wood dust reinforced epoxy composite. It was observed that addition of rice husk as filler is detrimental to almost all the mechanical properties. About 51% and 26.8% decrease in ultimate strength and Young’s Modulus for 40 wt% untreated rice husk reinforcement was observed. The corresponding decrease in flexural strength and flexural modulus was 51%. Similar trend was also observed in hardness and impact strength. However the mechanical properties of rice husk reinforced biocomposites are found to be superior than wood dust reinforced epoxy composite. SEM microscopy was also done to corroborate the results.

  19. Low-temperature mechanical properties of glass/epoxy laminates

    Science.gov (United States)

    Reed, R. P.; Madhukar, M.; Thaicharoenporn, B.; Martovetsky, N. N.

    2014-01-01

    Selected mechanical properties of glass/epoxy laminate candidates for use in the electrical turn and ground insulation of the ITER Central solenoid (CS) modules were measured. Short-beam shear and flexural tests have been conducted on various E-glass cloth weaves/epoxy laminates at 295 and 77 K. Types of glass weave include 1581, 7500, 7781, and 38050, which represent both satin and plain weaves. The epoxy, planned for use for vacuum-pressure impregnation of the CS module, consists of an anhydride-cured bisphenol F resin system. Inter-laminar shear strength, flexural elastic modulus, and flexural strength have been measured. The data indicate that these properties are dependent on the volume percent of glass. Short-beam shear strength was measured as a function of the span-to-thickness ratio for all laminates at 77 K. Comprehensive fractography was conducted to obtain the failure mode of each short-beam shear test sample.

  20. The Sun Sense Study: An Intervention to Improve Sun Protection in Children

    Science.gov (United States)

    Glasser, Alice; Shaheen, Magda; Glenn, Beth A.; Bastani, Roshan

    2010-01-01

    Objectives: To assess the effect of a multicomponent intervention on parental knowledge, sun avoidance behaviors, and sun protection practices in children 3-10 years. Methods: A randomized trial at a pediatric clinic recruited 197 caregiver-child pairs (90% parents). Intervention included a brief presentation and brochure for the parent and…

  1. After the Bell: Developing Sun Sense--Learning about Protection from the Sun's Rays

    Science.gov (United States)

    Farenga, Stephen J.; Ness, Daniel

    2008-01-01

    The American Academy of Dermatology (2008) reports that our students will experience 80% of their lifetime exposure to the Sun by the time they are 18. Further, research has demonstrated that continued exposure to the Sun's ultraviolet rays can lead to skin aging, sunburn, immune suppression, ocular melanoma, cataracts, corneal burns, and even…

  2. Research on fracture performance of epoxy asphalt concrete based on double-K fracture criterion

    Science.gov (United States)

    Zhang, M.; Qian, Z. D.; Xue, Y. C.

    2017-01-01

    After cracks appear on steel bridge deck epoxy asphalt concrete pavement, cracks propagate fast under vehicle load. This paper studied the fracture performance of epoxy asphalt concrete, utilized single edge notched beam (SEB) three-point bending test, measured the load (P) exerted on epoxy asphalt SEB; utilized digital camera to record the fracture process of epoxy asphalt SEB, extracted the images according to the required sampling frequency and utilized Image-Pro Plus to measure the crack mouth opening displacement (CMOD) of epoxy asphalt SEB on the extracted images; calculated the double-K fracture parameters according to the P-CMOD curve. Results indicate that of epoxy asphalt concrete is 1.11 MPa and of epoxy asphalt concrete is 2.31 MPa at -15°C of epoxy asphalt concrete is 1.02 MPa and of epoxy asphalt concrete is 1.83 MPa at -5°C of epoxy asphalt concrete is 0.77 MPa and of epoxy asphalt concrete is 1.82 MPa at 5°C. The double-K fracture parameters of epoxy asphalt concrete increase slightly when the temperature decreases at the scope of -15°C to 5°C. The relation of and is .

  3. 40 CFR 721.1850 - Toluene sulfonamide bis-phe-nol A epoxy adduct.

    Science.gov (United States)

    2010-07-01

    ... epoxy adduct. 721.1850 Section 721.1850 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Specific Chemical Substances § 721.1850 Toluene sulfonamide bis-phe-nol A epoxy adduct. (a) Chemical... as toluene sulfonamide bisphenol A epoxy adduct (PMN P-90-113) is subject to reporting under...

  4. Processing of Clay/Epoxy Nanocomposites with a Three-Roll Mill Machine

    Science.gov (United States)

    2003-01-01

    diglycidyl ether of bisphenol A ( DGEBA ) epoxy resin cured with methyl tetrahydrophthalic anhydride hardener from Vantico was used as the matrix. 1...34) was used to disperse and exfoliate the nanoclay particles in the epoxy matrix. First, the epoxy resin ( DGEBA ) was placed between the feed and center

  5. Influence of hydroxypropyl cellulose on molecular relaxations of epoxy-amine networks

    Directory of Open Access Journals (Sweden)

    Maria Inez G. Miranda

    2013-01-01

    Full Text Available A dynamic mechanical analysis (DMTA study was conducted on epoxy-amine networks crosslinked in the presence of low contents of hydroxypropyl cellulose (HPC. The epoxy resin chosen was diglycidylether of bisphenol-A (DGEBA and the crosslinker was 4,4'-diaminodiphenylmethane (DDM. In the glassy region, primary (α and secondary (β, γ relaxations originating from the epoxy and HPC components were well detected. Two primary relaxations of neat epoxy and epoxy/HPC systems, referred to as αepoxy and α'epoxy, could be detected, showing a particular glassy behavior for the systems studied in comparison with systems cured in bulk. The main relaxation temperature Tα (at the peak of αepoxy relaxation of the epoxy systems increased slightly with the addition of HPC. The activation energy for this transition (Tα of the epoxy-amine networks was determined both from tan δ and the peak temperatures for the loss modulus measured at various frequencies. The activation energy of the αepoxy relaxation determined from the loss modulus was more reliable than that based on tan δ. The addition of HPC lowered the activation energy of this αepoxy relaxation.

  6. A molecular dynamics study on the interaction between epoxy and functionalized graphene sheets

    DEFF Research Database (Denmark)

    Melro, Liliana Sofia S. F. P.; Pyrz, Ryszard; Jensen, Lars Rosgaard

    2016-01-01

    The interaction between graphene and epoxy resin was studied using molecular dynamics simulations. The interfacial shear strength and pull out force were calculated for functionalised graphene layers (carboxyl, carbonyl, and hydroxyl) and epoxy composites interfaces. The influence of functional...... and epoxy resin increases....

  7. Toughening mechanism in elastomer-modified epoxy resins, part 2

    Science.gov (United States)

    Yee, A. F.; Pearson, R. A.

    1984-01-01

    The role of matrix ductility on the toughenability and toughening mechanism of elastomer-modified DGEBRA epoxies was investigated. Matrix ductility was varied by using epoxide resins of varying epoxide monomer molecular weights. These epoxide resins were cured using 4,4' diaminodiphenyl sulfone (DDS) and, in some cases, modified with 10% HYCAR(r)CTBN 1300X8. Fracture roughness values for the neat epoxies were found to be almost independent on the monomer molecular weight of the epoxide resin used. However, it was found that the fracture toughness of the elastomer-modified epoxies was very dependent upon the epoxide monomer molecular weight. Tensile dilatometry indicated that the toughening mechanism, when present, is similar to the mechanisms found for the piperidine cured epoxies in Part 1. SEM and OM corroborate this finding. Dynamic mechanical studies were conducted to shed light on the toughenability of the epoxies. The time-dependent small strain behavior of these epoxies were separated into their bulk and shear components. The bulk component is related to brittle fracture, whereas the shear component is related to yielding. It can be shown that the rates of shear and bulk strain energy buildup for a given stress are uniquely determined by the values of Poisson's ratio, nu. It was found that nu increases as the monomer molecular weight of the epoxide resin used increases. This increase in nu can be associated with the low temperature beta relaxation. The effect of increasing cross-link density is to shift the beta relaxation to higher temperatures and to decrease the magnitude of the beta relaxation. Thus, increasing cross-link density decreases nu and increases the tendency towards brittle fracture.

  8. Understanding the strength of epoxy/polyimide interfaces

    Science.gov (United States)

    Hoontrakul, Patraporn

    Polyimides are commonly used as organic passivation layers for microelectronic devices due to their unique combination of low dielectric constant, high thermal stability, and excellent mechanical properties. Polyimides are well known to have poor adhesion to epoxy resins. Many surface treatment methods have been developed to increase epoxy-polyimide adhesion. These include various ion beam and plasma treatments as well as wet chemical methods. Our research goal is to understand the strength of epoxy-polyimide interfaces by studying the effect of polyimide chemical structure on epoxy-polyimide adhesion. Four polyimides that were chosen in this study were commonly used in microelectronic industries: poly (pyromellitic dianhydride-oxydianiline [PMDA-ODA], poly (3,3',4,4'-biphenyltetracarboxylic dianhydride-phenylene diamine [BPDA-PDA], poly (hexafluoroisopropylidene-diphthalic anhydride-oxydianiline) [6FDA-ODA], and 5(6)-Amino-1-(4-aminophenyl)-1,3,3, trimethylindanbenzophenonetetacarboxylic dianhydride copolymer [BTDA-DAPI). The adhesive strengths between an epoxy resin and these various polyimides were characterized using interfacial fracture mechanics and the critical interfacial strain energy release rates were found to be in the range of 20 J/m 2 to 179 J/m2. The locus of failure for fractured epoxy-polyimide interfaces were analyzed using scanning electron microscopy (SEM), X-ray Photoelectron Spectroscopy (XPS), and Fourier Transform Infrared Spectroscopy (FT-IR) and found to be at the interphase region for all four interfaces. The surface reactivity was analyzed using flow microcalorimetry (FMC), FT-IR, and the contact angles. Interestingly, the strength of the interfaces appeared to be related to the predicted interfacial widths from solubility parameter theory.

  9. Los cambios de temperatura en los revestimientos epoxi II

    Directory of Open Access Journals (Sweden)

    Fernández Cánovas, M.

    1970-04-01

    Full Text Available This article is the second part of a previous paper published by the author in no. 189 of this magazine. It describes the tests carried out to check the theoretical results published in the earlier article. The tests have consisted in submitting concrete slabs covered with a layer of epoxi mortar to certain thermal conditions, to check the behaviour of the covering in the face of thermal changes. In all the tests, described in detail in the article, the epoxi layer has behaved extremely well, and no bonding failure has been observed, nor failures in the concrete base or in the epoxi layer.Este artículo es la segunda parte de un trabajo publicado por el autor en el número 189 de esta revista, y en él se realiza una descripción de los ensayos prácticos llevados a cabo para complementar el estudio teórico publicado en aquella primera parte. Los ensayos han consistido en someter a placas de hormigón revestidas de una Kipa de mor tero epoxi a determinadas condiciones térmicas, con el fin de poder comprobar el comportamiento del revestimiento frente a los cambios de temperatura. En todos los ensayos realizados y que, con detalle, están descritos en este artículo, el comportamiento de los revestimientos de mortero epoxi ha sido excelente, no habiéndose notado ningún fallo de adherencia, ni roturas en la base de hormigón, ni en la capa de mortero epoxi.

  10. Thermoset Blends of an Epoxy Resin and Polydicyclopentadiene

    Energy Technology Data Exchange (ETDEWEB)

    Rohde, Brian J.; Le, Kim Mai; Krishnamoorti, Ramanan; Robertson, Megan L.

    2016-12-13

    The mechanical properties of two chemically distinct and complementary thermoset polymers were manipulated through development of thermoset blends. The thermoset blend system was composed of an anhydride-cured diglycidyl ether of bisphenol A (DGEBA)-based epoxy resin, contributing high tensile strength and modulus, and polydicyclopentadiene (PDCPD), which has a higher toughness and impact strength as compared to other thermoset polymers. Ultra-small-angle and small-angle X-ray scattering analysis explored the morphology of concurrently cured thermoset blends, revealing a macroscopically phase separated system with a surface fractal structure across blended systems of varying composition. The epoxy resin rich and PDCPD rich phases exhibited distinct glass transitions (Tg’s): the Tg observed at higher temperature was associated with the epoxy resin rich phase and was largely unaffected by the presence of PDCPD, whereas the PDCPD rich phase Tg systematically decreased with increasing epoxy resin content due to inhibition of dicyclopentadiene ring-opening metathesis polymerization. The mechanical properties of these phase-separated blends were in reasonable agreement with predictions by the rule of mixtures for the blend tensile strength, modulus, and fracture toughness. Scanning electron microscopy analysis of the tensile and fracture specimen fracture surfaces showed an increase in energy dissipation mechanisms, such as crazing, shear banding, and surface roughness, as the fraction of the more ductile component, PDPCD, increased. These results present a facile method to tune the mechanical properties of a toughened thermoset network, in which the high modulus and tensile strength of the epoxy resin can be largely retained at high epoxy resin content in the blend, while increasing the fracture toughness.

  11. 77 FR 34122 - Application of Sun Air Express, LLC, d/b/a Sun Air International for Commuter Authority

    Science.gov (United States)

    2012-06-08

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF TRANSPORTATION Office of the Secretary Application of Sun Air Express, LLC, d/b/a Sun Air International for Commuter... to show cause why it should not issue an order finding Sun Air Express, LLC d/b/a Sun...

  12. Toughness improvement of epoxy thermosets by adding dendritic structures

    OpenAIRE

    Flores Guillén, Marjorie Yusneiry

    2013-01-01

    Las resinas epoxi se encuentran entre los materiales termoestables más importantes utilizados en un gran abanico de aplicaciones tales como adhesivos, matrices para materiales compuestos, recubrimientos de superficies y encapsulamiento de componentes electrónicos. La principal razón de su amplio uso es la buena combinación entre resistencia a la tracción y a la corrosión, rigidez y buenas propiedades eléctricas. Sin embargo, debido a su elevado grado de entrecruzamiento, las resinas epoxi tie...

  13. Interlaminar fracture in woven carbon/epoxy laminates

    Directory of Open Access Journals (Sweden)

    Paulo N.B. Reis

    2014-10-01

    Full Text Available This paper describes an experimental study developed to characterize the mode I and mode II fracture toughness of carbon/epoxy woven composites, using DCB and ENF tests, respectively. The laminates were manufactured using an epoxy resin and twelve woven balanced bi-directional layers of carbon fibres, all of them with the same orientation (0/90º. Significant instantaneous delaminations were observed particularly for the DCB specimen, which were responsible for an oscillatory behaviour of GI versus crack length. The maximum values obtained for GIC and GIIC were 281 and 1800 J/m2, respectively.

  14. SYNTHESIS OF AN EPOXY-TERMINATED HYPERBRANCHED AROMATIC POLYESTER

    Institute of Scientific and Technical Information of China (English)

    Xia Wang; W.J. Feast

    2002-01-01

    An epoxy-terminated hyperbranched aromatic polyester (P3) was synthesized from a hyperbranched aromaticpolyester containing carboxylic acid end groups (P1), which was derived from the condensation polymerization of the AB2monomer, 5-acetoxyisophthalic acid. Polymer P1 was converted into the polymeric acid chloride by reaction with thionylchloride. The acid chloride was reacted with ethanol and glycidol to form a poly(ethyl ester) (P2) and an epoxy terminatedmaterial (P3), respectively. The reaction conditions in each step of these processes had to be controlled very carefully toavoid unwanted cross-linking reactions. The characterization of products and intermediates, including molecular weightdistributions and thermal properties, are reported.

  15. Epoxy composites based on inexpensive tire waste filler

    Science.gov (United States)

    Ahmetli, Gulnare; Gungor, Ahmet; Kocaman, Suheyla

    2014-05-01

    Tire waste (TW) was recycled as raw material for the preparation of DGEBA-type epoxy composite materials. The effects of filler amount and epoxy type on the mechanical properties of the composites were investigated. Tensile strength and Young's modulus of the composites with NPEL were generally higher than composites with NPEF. The appropriate mass level for TW in both type composites was found to be 20 wt%. The equilibrium water sorption of NPEL/TW and NPEF/TW composites for 14-day immersion was determined as 0.10 % and 0.21 %, respectively. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) were used for characterization of the composites.

  16. Chemical Interpretation of the Relaxed Permittivity during Epoxy Resin Cure.

    Science.gov (United States)

    1984-11-30

    contributions of other polar groups and their time variation are included. The isothermal cure of a stoichiometric mixture of a DGEBA epoxy resin, EPON 825. with...the DGEBA molecule, and since it contains only a single epoxide. this material does not crosslink. At low temperatures and at all frequencies, the...ratios of DGEBA and DDS gave an epoxy dipole moment of 8.SE-30 C-u and an amine dipole moment of 19.8E-30 C-m [10]. The experimental data and the curves

  17. PROGRESS IN PHASE INVERSION EMULSIFICATION FOR EPOXY RESIN WATERBORNE DISPERSIONS

    Institute of Scientific and Technical Information of China (English)

    Zhen-zhong Yang

    2007-01-01

    In this review,our recent work in phase inversion emulsification (PIE)for polymer(especially epoxy resin) waterborne dispersions is summarized.Based on experimental results about PIE process,the physical model is proposed which Can guide the synthesis of the waterborne dispersions such as polymer/nanoparticle composite dispersion.In the presence of a latent curing catalyst,PIE can give a crosslinkable epoxy resin waterborne dispersion.The dispersions can form cured transparent coatings with some unique properties such as UV shielding.They are promising in functional coatings,waterborne resin matrices for composites,and sizing for high performance fibers.

  18. Adhesion between Epoxy-Polysulfone Blends and Fibers

    Science.gov (United States)

    Brantseva, T. V.; Gorbatkina, Yu. A.; Kerber, M. L.

    2001-01-01

    The adhesive strength of a fiber-polymer interface is determined, where epoxy resin blends and linear heat-resistant thermoplastics - polysulfone (PSF) and polyetherimide (Ultem) - are used as matrices. Steel wire and polyamide (nylon-6) fibers are taken as reinforcing fillers. It is shown that the addition of PSF to epoxy resin results in a maximum on the concentration curve corresponding to a 10% PSF content. It is also found that the adhesive strength of the ED-20+Ultem-steel wire interface is practically independent of the modifier content under low (up to 10%) Ultem concentrations.

  19. Fracture behavior of silica nanoparticle filled epoxy resin

    Science.gov (United States)

    Dittanet, Peerapan

    This dissertation involves the addition of silica nanoparticles to a lightly crosslinked, model epoxy resin and investigates the effect of nanosilica content and particle size on glass transition temperature (Tg), coefficient of thermal expansion (CTE), Young's modulus (E), yield stress, and fracture toughness. This study aims to understand the influence of silica nanoparticle size, bimodal particle size distribution and silica content on the toughening behavior. The toughening mechanisms were determined using scanning electron microscopy (SEM), transmission electron microscopy (TEM) and transmission optical microscopy (TOM). The approach identifies toughening mechanisms and develops a toughening model from unimodal-particle size systems first, then extends these concepts to various mixtures micron- and nanometer-size particles in a similar model epoxy. The experimental results revealed that the addition of nanosilica did not have a significant effect on Tg or the yield stress of epoxy resin, i.e. the yield stress and Tg remained constant regardless of nanosilica particle size. As expected, the addition of nanosilica had a significant impact on CTE, modulus and fracture toughness. The CTE values of nanosilica-filled epoxies were found to decrease with increasing nanosilica content, which can be attributed to the much lower CTE of the nanosilica fillers. Interestingly, the decreases in CTE showed strong particle size dependence. The Young's modulus was also found to significantly improve with addition of nanosilica and increase with increasing filler content. However, the particle size did not exhibit any effect on the Young's modulus. Finally, the fracture toughness and fracture energy showed significant improvements with the addition of nanosilica, and increased with increasing filler content. The effect of particle size on fracture toughness was negligible. Observation of the fracture surfaces using SEM and TOM showed evidence of debonding of nanosilica particles

  20. A sun holiday is a sunburn holiday

    DEFF Research Database (Denmark)

    Petersen, Bibi; Thieden, Elisabeth; Philipsen, Peter Alshede

    2013-01-01

    Many people take holidays in sunny locations with the express aim of sunbathing. This may result in sunburn, which is a risk factor for skin cancer. We investigated 25 Danish sun seekers during a week's holiday in the Canary Islands. The percentage of body surface area with sunburn was determined......-specific UVR doses after adjustment for sun protection factor. Remarkably, we found that all volunteers sunburned at some point. The risk of sunburn correlated significantly with the adjusted body site-specific UVR dose. Furthermore, there was also a significant relationship between the daily UVR dose...... and percentage of body surface area with sunburn. Our study shows that holiday UVR exposure results in a high risk of sunburn, which potentially increases the risk of skin cancer. Possible protection by melanogenesis is insufficient to protect against sunburn during a 1-week sun holiday. Finally, our data...

  1. Precise nuclear physics for the sun

    Energy Technology Data Exchange (ETDEWEB)

    Bemmerer, Daniel

    2012-07-01

    For many centuries, the study of the Sun has been an important testbed for understanding stars that are further away. One of the first astronomical observations Galileo Galilei made in 1612 with the newly invented telescope concerned the sunspots, and in 1814, Joseph von Fraunhofer employed his new spectroscope to discover the absorption lines in the solar spectrum that are now named after him. Even though more refined and new modes of observation are now available than in the days of Galileo and Fraunhofer, the study of the Sun is still high on the agenda of contemporary science, due to three guiding interests. The first is connected to the ages-old human striving to understand the structure of the larger world surrounding us. Modern telescopes, some of them even based outside the Earth's atmosphere in space, have succeeded in observing astronomical objects that are billions of light-years away. However, for practical reasons precision data that are important for understanding stars can still only be gained from the Sun. In a sense, the observations of far-away astronomical objects thus call for a more precise study of the closeby, of the Sun, for their interpretation. The second interest stems from the human desire to understand the essence of the world, in particular the elementary particles of which it consists. Large accelerators have been constructed to produce and collide these particles. However, man-made machines can never be as luminous as the Sun when it comes to producing particles. Solar neutrinos have thus served not only as an astronomical tool to understand the Sun's inner workings, but their behavior on the way from the Sun to the Earth is also being studied with the aim to understand their nature and interactions. The third interest is strictly connected to life on Earth. A multitude of research has shown that even relatively slight changes in the Earth's climate may strongly affect the living conditions in a number of densely

  2. The Spectrum of Darkonium in the Sun

    CERN Document Server

    Kouvaris, Chris; Nielsen, Niklas Grønlund

    2016-01-01

    Dark matter that gets captured in the Sun may form positronium-like bound states if it self-interacts via light dark photons. In this case, dark matter can either annihilate to dark photons or recombine in bound states which subsequently also decay to dark photons. The fraction of the dark photons that leave the Sun without decaying to Standard Model particles have a characteristic energy spectrum which is a mixture of the direct annihilation process, the decays of ortho- and para- bound states and the recombination process. The ultimate decay of these dark photons to positron-electron pairs (via kinetic mixing) outside the Sun creates a distinct signal that can either identify or set strict constraints on dark photon models.

  3. The spectrum of darkonium in the Sun

    Science.gov (United States)

    Kouvaris, Chris; Langæble, Kasper; Grønlund Nielsen, Niklas

    2016-10-01

    Dark matter that gets captured in the Sun may form positronium-like bound states if it self-interacts via light dark photons. In this case, dark matter can either annihilate to dark photons or recombine in bound states which subsequently also decay to dark photons. The fraction of the dark photons that leave the Sun without decaying to Standard Model particles have a characteristic energy spectrum which is a mixture of the direct annihilation process, the decays of ortho- and para- bound states and the recombination process. The ultimate decay of these dark photons to positron-electron pairs (via kinetic mixing) outside the Sun creates a distinct signal that can either identify or set strict constraints on dark photon models.

  4. The sun since the Bronze Age

    Science.gov (United States)

    Eddy, J. A.

    1976-01-01

    An investigation is conducted concerning the behavior of the sun during the last 7000 years. The C-14 content in carbonaceous fossil material can be used as an indicator regarding the level of solar activity at the time when the carbon was assimilated in the process of photosynthesis. Living trees, such as the bristlecone pine, provide a solar activity record to about 3000 B.C. The record can be extended with the aid of well-preserved dead wood to beyond 5000 B.C. The results of an analysis of solar activity levels as a function of time on the basis of C-14 contents are presented in a graph. Attention is given to the Maunder Minimum, a history of the sun in the last 5000 years, an interpretation of the major C-14 excursions, and the sun and climate history.

  5. 'My Sun' and 'Guided by the Moon'

    Directory of Open Access Journals (Sweden)

    Rebecca Baillie

    2013-07-01

    Full Text Available My Sun and Guided by the Moon (2012 show the heavily pregnant artist with her swollen belly covered in gold and silver leaf. The work is suggestive that the connectivity experienced by an expectant mother, extends outwards, even as far as her relationship with the cosmos. The 'sun' portrait was taken on a bright September morning, and its partner image, the following October, on the night of a full moon. Female cycles and the importance of time passing during a pregnancy are referenced. Interestingly, bearing in mind that the artist gave birth to a son in November, creating the 'moon' portrait felt like a familiar, empowering and yet isolated expression of selfhood, whilst the 'sun/son' version exuded the energy of a collaboration, and stimulated feelings of joy, liberation and potentiality. By seeming contradiction, the boy was born on a full moon, exactly a month to the day that Guided by the Moon was taken.

  6. Semiautomatic sun shots with the WIDIF DIflux

    Directory of Open Access Journals (Sweden)

    J. L. Rasson

    2017-07-01

    Full Text Available The determination of magnetic declination angle entails finding two directions: geographic north and magnetic north. This paper deals with the former. The known way to do it by using the sun's calculable orientation in the sky is improved by using a device based on a WIDIF DIflux theodolite and split photocells positioned on its telescope ocular. Given the WIDIF accurate timing and location provided by the onboard GPS receiver, an astronomical computation can be effected to accurately and quickly determine the sun's azimuth and an auxiliary mark's azimuth. The precise sun's crossing of the split photocell, amplified by the telescope's magnification, allows azimuth accuracies of a few seconds of arc.

  7. Enhanced thermal and mechanical properties of epoxy composites by mixing thermotropic liquid crystalline epoxy grafted graphene oxide

    Directory of Open Access Journals (Sweden)

    B. Qi

    2014-07-01

    Full Text Available Graphene oxide (GO sheets were chemically grafted with thermotropic liquid crystalline epoxy (TLCP. Then we fabricated composites using TLCP-g-GO as reinforcing filler. The mechanical properties and thermal properties of composites were systematically investigated. It is found that the thermal and mechanical properties of the composites are enhanced effectively by the addition of fillers. For instance, the composites containing 1.0 wt% of TLCP-g-GO present impact strength of 51.43 kJ/m2, the tensile strength of composites increase from 55.43 to 80.85 MPa, the flexural modulus of the composites increase by more than 48%. Furthermore, the incorporation of fillers is effective to improve the glass transition temperature and thermal stability of the composites. Therefore, the presence of the TLCP-g-GO in the epoxy matrix could make epoxy not only stronger but also tougher.

  8. Study of of epoxy polymers aging under irradiation; Etude du vieillissement sous irradiation de polymeres epoxy

    Energy Technology Data Exchange (ETDEWEB)

    Longieras, N

    2004-01-01

    This work concerns the mechanisms of aging under irradiation of epoxy polymers. As epoxy network are insoluble, physicochemical characterisation is difficult to achieve and the interpretation is complex. Thus, we investigated first the degradation of a linear phenoxy polymer which contains DGEBA moiety as a repeat unit. Results obtained on this polymer were then used to study the more complex DGEBA/TETA network. In order to assess the role of oxygen on the aging mechanism, both radiolysis under helium and radio-oxidation under pure oxygen were carried out. The study of radiolysis under helium of phenoxy polymer shows a chain scission mechanism. This result was confirmed by the increase of molecular mobility measured by T{sub 2} and T{sub 1{rho}} NMR relaxation times. Identification of the degradation products were carried out using NMR and FTIR spectrometries. From the quantitative correlation of the whole experimental results, it was possible to determine the main polymer degradation mechanism: each chain scission is followed by the formation of two phenolic terminations, a loss of the intermediate aliphatic chain and the formation of acetone and isopropanol. Radio-oxidation displays a sharp degradation profile of oxidation products including formiate, ester and carboxylic acid groups. Like phenoxy polymer, DGEBA/TETA exhibits a chain scission mechanism. This result was confirmed by a net increase of NMR relaxation times. Dipolar spectra measured from 2DWISE solid state NMR two-dimensional sequence indicate that chain scission occur mainly at methylene amine site. Phenolic termination and acetone are not produced during aging of DGEBA/TETA network as in phenoxy polymer but new products are identified such as unsaturation, isopropyl alcohol, aldehyde, ketone, methide with two hetero-atom. Oxygen effect during irradiation leads mainly to amide formation and to carboxylic acid and ester. (author)

  9. Ongoing Mars Missions: Extended Mission Plans

    Science.gov (United States)

    Zurek, Richard; Diniega, Serina; Crisp, Joy; Fraeman, Abigail; Golombek, Matt; Jakosky, Bruce; Plaut, Jeff; Senske, David A.; Tamppari, Leslie; Thompson, Thomas W.; Vasavada, Ashwin R.

    2016-10-01

    Many key scientific discoveries in planetary science have been made during extended missions. This is certainly true for the Mars missions both in orbit and on the planet's surface. Every two years, ongoing NASA planetary missions propose investigations for the next two years. This year, as part of the 2016 Planetary Sciences Division (PSD) Mission Senior Review, the Mars Odyssey (ODY) orbiter project submitted a proposal for its 7th extended mission, the Mars Exploration Rover (MER-B) Opportunity submitted for its 10th, the Mars Reconnaissance Orbiter (MRO) for its 4th, and the Mars Science Laboratory (MSL) Curiosity rover and the Mars Atmosphere and Volatile Evolution (MVN) orbiter for their 2nd extended missions, respectively. Continued US participation in the ongoing Mars Express Mission (MEX) was also proposed. These missions arrived at Mars in 2001, 2004, 2006, 2012, 2014, and 2003, respectively. Highlights of proposed activities include systematic observations of the surface and atmosphere in twilight (early morning and late evening), building on a 13-year record of global mapping (ODY); exploration of a crater rim gully and interior of Endeavour Crater, while continuing to test what can and cannot be seen from orbit (MER-B); refocused observations of ancient aqueous deposits and polar cap interiors, while adding a 6th Mars year of change detection in the atmosphere and the surface (MRO); exploration and sampling by a rover of mineralogically diverse strata of Mt. Sharp and of atmospheric methane in Gale Crater (MSL); and further characterization of atmospheric escape under different solar conditions (MVN). As proposed, these activities follow up on previous discoveries (e.g., recurring slope lineae, habitable environments), while expanding spatial and temporal coverage to guide new detailed observations. An independent review panel evaluated these proposals, met with project representatives in May, and made recommendations to NASA in June 2016. In this

  10. The Sun in Time: Activity and Environment

    Directory of Open Access Journals (Sweden)

    Güdel Manuel

    2007-12-01

    Full Text Available The Sun's magnetic activity has steadily declined during its main-sequence life. While the solar photospheric luminosity was about 30% lower 4.6 Gyr ago when the Sun arrived on the main sequence compared to present-day levels, its faster rotation generated enhanced magnetic activity; magnetic heating processes in the chromosphere, the transition region, and the corona induced ultraviolet, extreme-ultraviolet, and X-ray emission about 10, 100, and 1000 times, respectively, the present-day levels, as inferred from young solar-analog stars. Also, the production rate of accelerated, high-energy particles was orders of magnitude higher than in present-day solar flares, and a much stronger wind escaped from the Sun, permeating the entire solar system. The consequences of the enhanced radiation and particle fluxes from the young Sun were potentially severe for the evolution of solar-system planets and moons. Interactions of high-energy radiation and the solar wind with upper planetary atmospheres may have led to the escape of important amounts of atmospheric constituents. The present dry atmosphere of Venus and the thin atmosphere of Mars may be a product of early irradiation and heating by solar high-energy radiation. High levels of magnetic activity are also inferred for the pre-main sequence Sun. At those stages, interactions of high-energy radiation and particles with the circumsolar disk in which planets eventually formed were important. Traces left in meteorites by energetic particles and anomalous isotopic abundance ratios in meteoritic inclusions may provide evidence for a highly active pre-main sequence Sun. The present article reviews these various issues related to the magnetic activity of the young Sun and the consequent interactions with its environment. The emphasis is on the phenomenology related to the production of high-energy photons and particles. Apart from the activity on the young Sun, systematic trends applicable to the entire

  11. The sun and heliosphere at solar maximum.

    Science.gov (United States)

    Smith, E J; Marsden, R G; Balogh, A; Gloeckler, G; Geiss, J; McComas, D J; McKibben, R B; MacDowall, R J; Lanzerotti, L J; Krupp, N; Krueger, H; Landgraf, M

    2003-11-14

    Recent Ulysses observations from the Sun's equator to the poles reveal fundamental properties of the three-dimensional heliosphere at the maximum in solar activity. The heliospheric magnetic field originates from a magnetic dipole oriented nearly perpendicular to, instead of nearly parallel to, the Sun's rotation axis. Magnetic fields, solar wind, and energetic charged particles from low-latitude sources reach all latitudes, including the polar caps. The very fast high-latitude wind and polar coronal holes disappear and reappear together. Solar wind speed continues to be inversely correlated with coronal temperature. The cosmic ray flux is reduced symmetrically at all latitudes.

  12. Haloes around the Moon and the Sun

    Science.gov (United States)

    Gaina, Alex; Gaina, Danielle A.

    2008-10-01

    The authors observations of the Haloes around the Moon and the Sun during few last years are reported. A Historical review of the phenomenon is given since the observations by Benvenuto Cellini and Gaston Tissandier is given. A photograph (from eight available) of the Halo around the Sun observed in Chisinau on 21 May 2007 is included. The Halo from 21 May 2007 occured after a very fast increasing of the air temperature during one day by more than 15 Deg. The authors consider, that the phenomenon is due to scattering of light on Cirri clouds(7 km altitude), present on the sky during that day. They formed due to very fast heating.

  13. SunShot Initiative Fact Sheet

    Energy Technology Data Exchange (ETDEWEB)

    DOE Solar Energy Technologies Office

    2015-04-01

    The U.S. Department of Energy (DOE) SunShot Initiative is a collaborative national effort launched in 2011 that aggressively drives innovation to make solar energy fully cost competitive with traditional energy sources before the end of the decade. The SunShot fact sheet outlines goals and successes of the program as it works with private companies, universities, non-profit organizations, state and local governments, and national laboratories to drive down the cost of solar electricity to $0.06 per kilowatt-hour, without incentives, by the year 2020.

  14. Radio emission of the sun and planets

    CERN Document Server

    Zheleznyakov, V V

    1970-01-01

    International Series of Monographs in Natural Philosophy, Volume 25: Radio Emission of the Sun and Planets presents the origin of the radio emission of the planets. This book examines the outstanding triumphs achieved by radio astronomy of the solar system. Comprised of 10 chapters, this volume begins with an overview of the physical conditions in the upper layers of the Sun, the Moon, and the planets. This text then examines the three characteristics of radio emission, namely, the frequency spectrum, the polarization, and the angular spectrum. Other chapters consider the measurements of the i

  15. Cassini Operational Sun Sensor Risk Management During Proximal Orbit Saturn Ring Plane Crossings

    Science.gov (United States)

    Bates, David M.

    2016-01-01

    NASA's Cassini Spacecraft, launched on October 15th, 1997 which arrived at Saturn on June 30th, 2004, is the largest and most ambitious interplanetary spacecraft in history. As the first spacecraft to achieve orbit at Saturn, Cassini has collected science data throughout its four-year prime mission (2004–08), and has since been approved for a first and second extended mission through 2017. As part of the final extended missions, Cassini will begin an aggressive and exciting campaign of high inclination, low altitude flybys within the inner most rings of Saturn, skimming Saturn’s outer atmosphere, until the spacecraft is finally disposed of via planned impact with the planet. This final campaign, known as the proximal orbits, requires a strategy for managing the Sun Sensor Assembly (SSA) health, the details of which are presented in this paper.

  16. Mission interplanetary: Using radioisotope power to explore the solar system

    Energy Technology Data Exchange (ETDEWEB)

    Bennett, Gary L., E-mail: UserSg4282@aol.com

    2008-03-15

    The exploration of space both by humans and robots has been greatly enhanced and, in many cases, enabled by the use of radioisotope power sources (RPSs) to power and/or heat scientific instruments. Radioisotope power sources have enabled such breakthrough missions as the Pioneer flights to Jupiter, Saturn and beyond; the Voyager flights to Jupiter, Saturn, Uranus, Neptune, and beyond; the Apollo lunar surface experiments; the Viking Lander studies of Mars; the Galileo spacecraft that orbited Jupiter; the Ulysses mission to study the polar regions of the Sun; the Cassini spacecraft orbiting Saturn; and the recently launched New Horizons spacecraft to Pluto. Radioisotope heater units have enhanced or enabled the Apollo Early Scientific Experiment Package and the Mars exploration rover missions (Sojourner, Spirit and Opportunity). Since 1961, the United States has successfully flown 41 radioisotope thermoelectric generators (RTGs) to provide electrical power for 23 space missions.

  17. Full Mission Astronaut Radiation Exposure Assessments for Long Duration Lunar Surface Missions

    Science.gov (United States)

    Adamczyk, Anne M.; Clowdsley, Martha S.; Qualls, Garry D.; Blattnig, Steve B.; Lee, Kerry T.; Fry, Dan J.; Stoffle, Nicholas N.; Simonsen, Lisa C.; Slaba, Tony C.; Walker, Steven A.; Zapp, Edward N.

    2010-01-01

    Risk to astronauts due to ionizing radiation exposure is a primary concern for missions beyond Low Earth Orbit (LEO) and will drive mission architecture requirements, mission timelines, and operational practices. Both galactic cosmic ray (GCR) and solar particle event (SPE) environments pose a risk to astronauts for missions beyond LEO. The GCR environment, which is made up of protons and heavier ions covering a broad energy spectrum, is ever present but varies in intensity with the solar cycle, while SPEs are sporadic events, consisting primarily of protons moving outward through the solar system from the sun. The GCR environment is more penetrating and is more difficult to shield than SPE environments, but lacks the intensity to induce acute effects. Large SPEs are rare, but they could result in a lethal dose, if adequate shielding is not provided. For short missions, radiation risk is dominated by the possibility of a large SPE. Longer missions also require planning for large SPEs; adequate shielding must be provided and operational constraints must allow astronauts to move quickly to shielded locations. The dominant risk for longer missions, however, is GCR exposure, which accumulates over time and can lead to late effects such as cancer. SPE exposure, even low level SPE exposure received in heavily shielded locations, will increase this risk. In addition to GCR and SPE environments, the lunar neutron albedo resulting mainly from the interaction of GCRs with regolith will also contribute to astronaut risk. Full mission exposure assessments were performed for proposed long duration lunar surface mission scenarios. In order to accomplish these assessments, radiation shielding models were developed for a proposed lunar habitat and rover. End-to-End mission exposure assessments were performed by first calculating exposure rates for locations in the habitat, rover, and during extra-vehicular activities (EVA). Subsequently, total mission exposures were evaluated for

  18. JPL Mission Bibliometrics

    Science.gov (United States)

    Coppin, Ann

    2013-01-01

    For a number of years ongoing bibliographies of various JPL missions (AIRS, ASTER, Cassini, GRACE, Earth Science, Mars Exploration Rovers (Spirit & Opportunity)) have been compiled by the JPL Library. Mission specific bibliographies are compiled by the Library and sent to mission scientists and managers in the form of regular (usually quarterly) updates. Charts showing publications by years are periodically provided to the ASTER, Cassini, and GRACE missions for supporting Senior Review/ongoing funding requests, and upon other occasions as a measure of the impact of the missions. Basically the Web of Science, Compendex, sometimes Inspec, GeoRef and Aerospace databases are searched for the mission name in the title, abstract, and assigned keywords. All get coded for journal publications that are refereed publications.

  19. Structural and electrical properties of functionalized multiwalled carbon nanotube/epoxy composite

    Science.gov (United States)

    Gantayat, S.; Rout, D.; Swain, S. K.

    2016-05-01

    The effect of the functionalization of multiwalled carbon nanotube on the structure and electrical properties of composites was investigated. Samples based on epoxy resin with different weight percentage of MWCNTs were prepared and characterized. The interaction between MWCNT & epoxy resin was noticed by Fourier transform infrared spectroscopy (FTIR). The structure of functionalized multiwalled carbon nanotube (f-MWCNT) reinforced epoxy composite was studied by field emission scanning electron microscope (FESEM). The dispersion of f-MWCNT in epoxy resin was evidenced by high resolution transmission electron microscope (HRTEM). Electrical properties of epoxy/f-MWCNT nanocomposites were measured & the result indicated that the conductivity increased with increasing concentration of f-MWCNTs.

  20. Structural and electrical properties of functionalized multiwalled carbon nanotube/epoxy composite

    Energy Technology Data Exchange (ETDEWEB)

    Gantayat, S., E-mail: subhra-gantayat@rediffmail.com; Rout, D. [School of Applied Sciences, KIIT University, Bhubaneswar-751024, Odisha (India); Swain, S. K. [Department of Chemistry, Veer Surendra Sai University of Technology, Burla, Sambalpur-768018, Odisha (India)

    2016-05-23

    The effect of the functionalization of multiwalled carbon nanotube on the structure and electrical properties of composites was investigated. Samples based on epoxy resin with different weight percentage of MWCNTs were prepared and characterized. The interaction between MWCNT & epoxy resin was noticed by Fourier transform infrared spectroscopy (FTIR). The structure of functionalized multiwalled carbon nanotube (f-MWCNT) reinforced epoxy composite was studied by field emission scanning electron microscope (FESEM). The dispersion of f-MWCNT in epoxy resin was evidenced by high resolution transmission electron microscope (HRTEM). Electrical properties of epoxy/f-MWCNT nanocomposites were measured & the result indicated that the conductivity increased with increasing concentration of f-MWCNTs.

  1. PHASE STRUCTURE AND PROPERTIES OF EPOXY RESIN MODIFIED BY POLYSILOXANE BEARING PENDANT AMINO GROUPS

    Institute of Scientific and Technical Information of China (English)

    Bing Zhang; Xiang-luan Liu; Ying Huang

    2000-01-01

    Polysiloxane-modified epoxy resins were prepared through the reaction of epoxy resin with polydimethylsiloxanes bearing pendant N-(β-aminoethyl)-γ-aminopropyl groups. The morphology and properties of the cured epoxy resins modified by the polysiloxanes were investigated. It was found that the phase structure and properties of the cured epoxy resins depend mainly on the amino group content in the polydimethylsiloxane and the level of the modifier. The change of phase structure in the cured epoxy resin systems was responsible for the dramatic change in their mechanical and surface properties.

  2. Mission design for the infrared astronomical satellite /IRAS/

    Science.gov (United States)

    Lundy, S. A.; Mclaughlin, W. I.; Pouw, A.

    1979-01-01

    IRAS, a joint United States, Netherlands, United Kingdom astronomical satellite, is scheduled to be launched early in 1981 with the purpose of completing an all-sky survey in the infrared wavelengths from 8 to 120 microns and to observe objects of special interest. The mission design is driven by thermal constraints primarily determined by the Sun and Earth; the orbit and survey strategy must be chosen so as to satisfy the mission requirements before the cryogenic system is depleted of its liquid helium. Computer graphics help the designer choose valid survey strategies and evaluate resulting sky coverage.

  3. BcSUN1, a B. cinerea SUN-Family Protein, Is Involved in Virulence

    Science.gov (United States)

    Pérez-Hernández, Alicia; González, Mario; González, Celedonio; van Kan, Jan A. L.; Brito, Nélida

    2017-01-01

    BcSUN1 is a glycoprotein secreted by Botrytis cinerea, an important plant pathogen that causes severe losses in agriculture worldwide. In this work, the role of BcSUN1 in different aspects of the B. cinerea biology was studied by phenotypic analysis of Bcsun1 knockout strains. We identified BcSUN1 as the only member of the Group-I SUN family of proteins encoded in the B. cinerea genome, which is expressed both in axenic culture and during infection. BcSUN1 is also weakly attached to the cellular surface and is involved in maintaining the structure of the cell wall and/or the extracellular matrix. Disruption of the Bcsun1 gene produces different cell surface alterations affecting the production of reproductive structures and adhesion to plant surface, therefore reducing B. cinerea virulence. BcSUN1 is the first member of the SUN family reported to be involved in the pathogenesis of a filamentous fungus. PMID:28163701

  4. Sun exposure and sun protection practices of children and their parents.

    LENUS (Irish Health Repository)

    Kiely, A D

    2009-05-01

    The primary aims of this study were: to estimate sun exposure in hours of children in Cork during the summer months; to examine sun protection measures used by children and their parents and to explore parental knowledge of sun exposure and protection. A cross-sectional study, using a semi-structured questionnaire, was conducted in June 2006 in primary schools, pre-schools and creches throughout Cork City and County. Parents of 250 children aged less than 12 years were sampled. Mean sun exposure of Cork children was 40.9 hours per week in the summer months, with 77 (46.1%) children developing sunburn. 59.3% of the studied children were of skin type 1 or 2. 95 (57%) children on weekdays and 137 (82%) children at weekends were exposed to the sun between 11 am and 3 pm. Sunscreen and hats\\/caps were the most common protection measures used. A minority used protective clothing, sunglasses or sought shade. Thirty one (30.5%) children had sunscreen reapplied every 2 hours. Knowledge of sun protection was considerable among Irish parents. However the frequency of sunburn among Irish children suggests we are not providing them with adequate sun protection.

  5. Earth as an Extrasolar Planet: Earth Model Validation Using EPOXI Earth Observations

    Science.gov (United States)

    Robinson, Tyler D.; Meadows, Victoria S.; Crisp, David; Deming, Drake; A'Hearn, Michael F.; Charbonneau, David; Livengood, Timothy A.; Seager, Sara; Barry, Richard; Hearty, Thomas; hide

    2011-01-01

    The EPOXI Discovery Mission of Opportunity reused the Deep Impact flyby spacecraft to obtain spatially and temporally resolved visible photometric and moderate resolution near-infrared (NIR) spectroscopic observations of Earth. These remote observations provide a rigorous validation of whole disk Earth model simulations used to better under- stand remotely detectable extrasolar planet characteristics. We have used these data to upgrade, correct, and validate the NASA Astrobiology Institute s Virtual Planetary Laboratory three-dimensional line-by-line, multiple-scattering spectral Earth model (Tinetti et al., 2006a,b). This comprehensive model now includes specular reflectance from the ocean and explicitly includes atmospheric effects such as Rayleigh scattering, gas absorption, and temperature structure. We have used this model to generate spatially and temporally resolved synthetic spectra and images of Earth for the dates of EPOXI observation. Model parameters were varied to yield an optimum fit to the data. We found that a minimum spatial resolution of approx.100 pixels on the visible disk, and four categories of water clouds, which were defined using observed cloud positions and optical thicknesses, were needed to yield acceptable fits. The validated model provides a simultaneous fit to the Earth s lightcurve, absolute brightness, and spectral data, with a root-mean-square error of typically less than 3% for the multiwavelength lightcurves, and residuals of approx.10% for the absolute brightness throughout the visible and NIR spectral range. We extend our validation into the mid-infrared by comparing the model to high spectral resolution observations of Earth from the Atmospheric Infrared Sounder, obtaining a fit with residuals of approx.7%, and temperature errors of less than 1K in the atmospheric window. For the purpose of understanding the observable characteristics of the distant Earth at arbitrary viewing geometry and observing cadence, our validated

  6. Kepler: NASA's First Mission Capable of Finding Earth-Size Planets

    Science.gov (United States)

    Borucki, William J.

    2009-01-01

    Kepler, a NASA Discovery mission, is a spaceborne telescope designed to search a nearby region of our galaxy for Earth-size planets orbiting in the habitable zone of stars like our sun. The habitable zone is that region around a start where the temperature permits water to be liquid on the surface of a planet. Liquid water is considered essential forth existence of life. Mission Phases: Six mission phases have been defined to describe the different periods of activity during Kepler's mission. These are: launch; commissioning; early science operations, science operations: and decommissioning

  7. Can simultaneous contact allergies to phenyl glycidyl ether and epoxy resins of the bisphenol A/F-types be explained by contamination of the epoxy resins?

    Science.gov (United States)

    Pontén, Ann; Zimerson, Erik; Bruze, Magnus

    2008-11-01

    Simultaneous contact allergies to epoxy resins based on diglycidyl ether of bisphenol A (DGEBA-R) or epoxy resins of the bisphenol F-type and the reactive diluent phenyl glycidyl ether (PGE) have been reported. The reason might be cross-reactivity, exposure to an epoxy resin system with PGE as a component, or contamination by PGE in the epoxy resin. To study contamination by PGE, 20 commercial epoxy resins were analysed for the presence of PGE. To study contact allergy to PGE and its relation to epoxy resins by inserting PGE in the standard series. Among 2227 patients, 7 reacted to PGE. Of 23 (30%) patients, 7 with contact allergy to DGEBA-R and 7/19 (37%) with contact allergy to an epoxy resin of the bisphenol F-type reacted to PGE. All 7 patients with contact allergy to PGE reacted both to the DGEBA-R and to the epoxy resin of the bisphenol F-type. PGE was found in 90% of the investigated resins. The amounts of PGE ranged between 0.004% w/w and 0.18% w/w. Most probably, the presence of PGE as a contaminant in epoxy resins is of minor importance for the sensitization, but possibly the contamination of PGE might elicit contact dermatitis in individuals with a high reactivity to PGE.

  8. Ulysses returns to the Sun's south pole and encounters blustery solar weather

    Science.gov (United States)

    2000-09-01

    Conditions are very different from those Ulysses encountered during its first south polar pass in 1994 when solar activity, which is related to the magnetic behaviour of the Sun, was very low. Then, the solar wind at high latitudes was fast, but steady. This latest polar pass gives scientists the opportunity to learn just how different the polar regions of the Sun are at solar maximum compared with minimum. After spending four months above 70o south, Ulysses will swing towards the equator early next year to turn its attention to the northern hemisphere, beginning its passage over the north pole on 3 September 2001. Although it will be travelling the same path it followed six years ago, conditions will be quite different and new discoveries are eagerly awaited. Since launch in October 1990, Ulysses has already proved one of the most successful interplanetary missions ever. A joint ESA/NASA mission, it is the first spacecraft ever to be launched into an orbit outside the ecliptic, the plane in which the planets orbit the Sun. From this unique vantage point, it has changed our view of the heliosphere, the region of space filled by the solar wind and over which our Sun exerts its influence. At solar minimum, instruments on board Ulysses found that the fast solar wind, emanating from the Sun's poles, blows at a steady 750 km/s and fills a large fraction of the heliosphere. The state-of-the-art instruments were also able to show that the boundary between the fast wind and the slower, more variable wind from the equatorial regions, is surprisingly sharp. Another surprise was that the effects of collisions, occurring at low latitudes between fast and slow wind streams, continue to be felt all the way up to the poles. Ulysses discoveries, however, have not been confined to the Sun and heliosphere. Instruments on board the spacecraft also made the first ever measurements of dust particles and neutral helium atoms originating outside the solar system. These findings have

  9. Epoxy-acrylic core-shell particles by seeded emulsion polymerization.

    Science.gov (United States)

    Chen, Liang; Hong, Liang; Lin, Jui-Ching; Meyers, Greg; Harris, Joseph; Radler, Michael

    2016-07-01

    We developed a novel method for synthesizing epoxy-acrylic hybrid latexes. We first prepared an aqueous dispersion of high molecular weight solid epoxy prepolymers using a mechanical dispersion process at elevated temperatures, and we subsequently used the epoxy dispersion as a seed in the emulsion polymerization of acrylic monomers comprising methyl methacrylate (MMA) and methacrylic acid (MAA). Advanced analytical techniques, such as scanning transmission X-ray microscopy (STXM) and peak force tapping atomic force microscopy (PFT-AFM), have elucidated a unique core-shell morphology of the epoxy-acrylic hybrid particles. Moreover, the formation of the core-shell morphology in the seeded emulsion polymerization process is primarily attributed to kinetic trapping of the acrylic phase at the exterior of the epoxy particles. By this new method, we are able to design the epoxy and acrylic polymers in two separate steps, and we can potentially synthesize epoxy-acrylic hybrid latexes with a broad range of compositions.

  10. Thermal and Mechanical Characteristics of Polymer Composites Based on Epoxy Resin, Aluminium Nanopowders and Boric Acid

    Science.gov (United States)

    Nazarenko, O. B.; Melnikova, T. V.; Visakh, P. M.

    2016-01-01

    The epoxy polymers are characterized by low thermal stability and high flammability. Nanoparticles are considered to be effective fillers of polymer composites for improving their thermal and functional properties. In this work, the epoxy composites were prepared using epoxy resin ED-20, polyethylene polyamine as a hardener, aluminum nanopowder and boric acid fine powder as flame-retardant filler. The thermal characteristics of the obtained samples were studied using thermogravimetric analysis and differential scanning calorimetry. The mechanical characteristics of epoxy composites were also studied. It was found that an addition of all fillers enhances the thermal stability and mechanical characteristics of the epoxy composites. The best thermal stability showed the epoxy composite filled with boric acid. The highest flexural properties showed the epoxy composite based on the combination of boric acid and aluminum nanopowder.

  11. Influences of carbon nanofillers on mechanical performance of epoxy resin polymer

    Science.gov (United States)

    Singh, Shraddha; Srivastava, V. K.; Prakash, Rajiv

    2015-03-01

    The influence of multi-walled carbon nanotubes (MWCNTs) and graphene nanoplatelets (GnPs) on epoxy resin was investigated to compare their mechanical properties. MWCNT/epoxy resin and GnP/epoxy resin composites were compared with each other for their tensile strength, compressive strength, Charpy Impact and Izod impact energy with the variation of weight percentage ratio of nanofiller ranging from 0.5, 1.0, 2.0 and 3.0, respectively. The result shows that GnP/epoxy resin composite gave better tensile and compressive strength compared to MWCNT/epoxy resin composite whereas Izod impact energy, Charpy impact energy and dynamic fracture toughness of MWCNT/epoxy resin composite resulted in better impact resistance than the GnP/epoxy resin composite. Thermal stability and microstructural properties of composites were measured using Thermogravimetric analysis (TGA), transmission electron microscope (TEM) and scanning electron microscope (SEM).

  12. Thermal expansion of an epoxy-glass microsphere composite

    Science.gov (United States)

    Price, H. L.; Burks, H. D.

    1977-01-01

    The thermal expansion of a composite of epoxy (diglycidyl ether of bisphenol A) and solid glass microspheres was investigated. The microspheres had surfaces which were either untreated or treated with a silicone release agent, an epoxy coupling agent, or a general purpose silane coupling agent. Both room temperature (about 300 K) and elevated temperature (about 475 K) cures were used for the epoxy. Two microsphere size ranges were used, about 50 microns, which is applicable in filled moldings, and about 125 microns, which is applicable as bond line spacers. The thermal expansion of the composites was measured from 300 to 350 K or from 300 to 500 K, depending on the epoxy cure temperature. Measurements were made on composites containing up to .6 volume fraction microspheres. Two predictive models, which required only the values of thermal expansion of the polymer and glass and their specific gravities, were tested against the experimental data. A finite element analysis was made of the thermal strain of a composite cell containing a single microsphere surrounded by a finite-thickness interface.

  13. Synchrotron Radiation Investigation in Epoxy Resin Modified with Polysiloxane System

    Science.gov (United States)

    Gan, Wenjun; Li, Weizhen; Ding, Jindian; Gu, Xiaodan; Wang, Cheng

    2014-03-01

    Epoxy resins are one of the most important classes of thermosetting polymers. Epoxy resin modified with polysiloxane is expected that the siloxane moiety may exert its qualities of thermal stability, impact toughness and surface-modification properties. Our group tried to introduce polysiloxane into epoxy resin by blending diglycidyl-ether of bisphenol-A with epoxypropoxypropyl terminated polydimethyl-siloxane and polyetherimide-siloxane in different proportion. These polysiloxane modified epoxy resins have been investigated using a combination of small- and wide angle X-ray scatterings (SAXS and WAXS) and scanning transmission soft X-ray microscopy (STXM). Nano- to micro-scale domain size, distribution and chemical composition were observed with spatial and spectroscopic sensitivities offered by both hard and soft x-ray scattering/microscopy. In-situ SAXS experiments were performed to understand the mechanism of microphase separation and dynamics of nanostructure evolution. Acknowledgment: The authors thank Shanghai Municipal Education Commission (Overseas Visiting Scholar Program 2012) and Shanghai University of Engineering Science (2011xz04) for financial supports.

  14. Development of Partial Discharge Sensing Device for Epoxy Resin Bushing

    Science.gov (United States)

    Mutakamihigashi, Tatsuya; Kawasaki, Makoto; Hashiba, Yasuhito

    For the electric power equipment and the cables, prevention of accident is very important. And in substations, a lot of solid insulations using epoxy resin are introduced into cubicle-type switchgears because of its high insulation reliability and down-sizing ability. We know a phenomenon that partial discharge occur when electric installation have degraded. When void or crack exist in the polymer insulating materials or interface of conductor, partial discharge is caused and finally results in breakdown. In recent years, the feature is seen in the partial discharge generated in the epoxy resin before and after the progress of electric tree by our research. Electro-magnetic wave spectra radiated from partial discharge have specific frequency region from 200MHz to 450MHz. We developed the sensing device that can detect the electric discharge by receiving the signal by mobile antenna. We proved the performance of this equipment in operating substations; As a result, partial discharge in epoxy resin was detected by electro-magnetic wave. And then, we removed epoxy resin bushing from the cubicle and measured partial discharge by discharging current, we confirmed that presumed level is correct.

  15. Mechanisms of Interactions of Energetic Electrons with Epoxy Resins

    Science.gov (United States)

    Gupta, A.; Coulter, D. R.; Tsay, F. D.; Moacanin, J.

    1982-01-01

    The mechanism of deactivation of energy of excitation in a resin system was investigated on optical excitation as well as excitation by high energy electrons. This mechanism involves formation of excited state complexes, known as exciplexes which have a considerable charge transfer character. This mechanism will be used to develop a degradation model for epoxy matrix materials deployed in a space environment.

  16. Novel Epoxy Activated Hydrogels for Solving Lactose Intolerance

    Directory of Open Access Journals (Sweden)

    Magdy M. M. Elnashar

    2014-01-01

    Full Text Available “Lactose intolerance” is a medical problem for almost 70% of the world population. Milk and dairy products contain 5–10% w/v lactose. Hydrolysis of lactose by immobilized lactase is an industrial solution. In this work, we succeeded to increase the lactase loading capacity to more than 3-fold to 36.3 U/g gel using epoxy activated hydrogels compared to 11 U/g gel using aldehyde activated carrageenan. The hydrogel’s mode of interaction was proven by FTIR, DSC, and TGA. The high activity of the epoxy group was regarded to its ability to attach to the enzyme’s –SH, –NH, and –OH groups, whereas the aldehyde group could only bind to the enzyme’s –NH2 group. The optimum conditions for immobilization such as epoxy chain length and enzyme concentration have been studied. Furthermore, the optimum enzyme conditions were also deliberated and showed better stability for the immobilized enzyme and the Michaelis constants, Km and Vmax, were doubled. Results revealed also that both free and immobilized enzymes reached their maximum rate of lactose conversion after 2 h, albeit, the aldehyde activated hydrogel could only reach 63% of the free enzyme. In brief, the epoxy activated hydrogels are more efficient in immobilizing more enzymes than the aldehyde activated hydrogel.

  17. ELASTOMERIC REACTIVE MICROGELS AS TOUGHENER FOR EPOXY ADHESIVES

    Institute of Scientific and Technical Information of China (English)

    ZHU Zheng; XUE Ruilan; YU Yunchao

    1987-01-01

    Elastomeric reactive microgels were evaluated as toughener for epoxy adhesives. It turned out that elastomeric microgels can improve lap shear strength and peel strength greatly. The glass transition temperature of the resin matrix was not affected by the presence of dispersed microgel particles, and thus the microgel-toughened adhesives have a good bond strength at elevated temperatures.

  18. Characterization of fracture toughness of epoxy resin after hygrothermal aging

    KAUST Repository

    Quispe, Gustavo Q.

    2013-07-01

    Characterization of fracture toughness of epoxy resin after hygrothermal ageing Gustavo Quino Quispe The aim of this work is to characterize the e ects of hygrothermal aging in the plain strain fracture toughness of the epoxy system composed by cycloaliphatic epoxy resin and diglycidyl ether of bisphenol-A (DGEBA). For this, after having been under hygrothermal aging in a climatic chamber, epoxy samples were studied using ASTM D5045 fracture toughness test, and micrography and roughness measurements of the fracture surface. It is reported a rapid decrease of GIc and KIc during the rst 2 days. Moreover, a numerical model [13] was used to simulate and see with more detail the water absorption in the aged samples. From that, it was observed the heterogeneous distribution of water. Accordingly, it was proposed that the results should be correlated with the water content at the vicinity of the crack tip. Consequently, it was possible to obtain, by quasi-static simulations, the ideal load-displacement curves of crack propagation in the heterogeneous samples. Finally, another contribution of this work is the study of the fracture surface, that gives a clue of the relationship among the fracture energy, the appearance of microcracks in the fracture surface, and the roughness (Ra).

  19. Piezoelectric and mechanical properties of structured PZT-epoxy composites

    NARCIS (Netherlands)

    James, N.K.; Ende, D.A. van den; Lafont, U.; Zwaag, S. van der; Groen, W.A.

    2013-01-01

    Structured lead zirconium titanate (PZT)-epoxy composites are prepared by dielectrophoresis. The piezoelectric and dielectric properties of the composites as a function of PZT volume fraction are investigated and compared with the corresponding unstructured composites. The effect of poling voltage o

  20. Piezoelectric and mechanical properties of structured PZT–epoxy composites

    NARCIS (Netherlands)

    Kunnamkuzhakkal James, N.; Van den Ende, D.; Lafont, U.; Van der Zwaag, S.; Groen, W.A.

    2013-01-01

    Structured lead zirconium titanate (PZT)–epoxy composites are prepared by dielectrophoresis. The piezoelectric and dielectric properties of the composites as a function of PZT volume fraction are investigated and compared with the corresponding unstructured composites. The effect of poling voltage o