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Sample records for earth hysteresis experiment

  1. Thermodynamic Analysis of Snowball Earth Hysteresis Experiment: Efficiency, Entropy Production, and Irreversibility

    NASA Astrophysics Data System (ADS)

    Lucarini, Valerio; Fraedrich, Klaus; Lunkeit, Frank

    2010-05-01

    We present an extensive thermodynamic analysis of a hysteresis experiment performed on a simplified yet Earth-like climate model. We slowly vary the solar constant by 20% around the present value and detect that for a large range of values of the solar constant the realization of snowball or of regular climate conditions depends on the history of the system. Using recent results on the global climate thermodynamics, we show that the two regimes feature radically different properties. The efficiency of the climate machine monotonically increases with decreasing solar constant in present climate conditions, whereas the opposite takes place in snowball conditions. Instead, entropy production is monotonically increasing with the solar constant in both branches of climate conditions, and its value is about four times larger in the warm branch than in the corresponding cold state. Finally, the degree of irreversibility of the system, measured as the fraction of excess entropy production due to irreversible heat transport processes, is much higher in the warm climate conditions, with an explosive growth in the upper range of the considered values of solar constants. Whereas in the cold climate regime a dominating role is played by changes in the meridional albedo contrast, in the warm climate regime changes in the intensity of latent heat fluxes are crucial for determining the observed properties. This substantiates the importance of addressing correctly the variations of the hydrological cycle in a changing climate. An interpretation of the climate transitions at the tipping points based upon macro-scale thermodynamic properties is also proposed. Our results support the adoption of a new generation of diagnostic tools based on the 2nd law of thermodynamics for auditing climate model and outline a set of parameterizations to be used in conceptual and intermediate complexity models or for the reconstruction of the past climate conditions

  2. Effect of Electron Energy Distribution on the Hysteresis of Plasma Discharge: Theory, Experiment, and Modeling

    PubMed Central

    Lee, Hyo-Chang; Chung, Chin-Wook

    2015-01-01

    Hysteresis, which is the history dependence of physical systems, is one of the most important topics in physics. Interestingly, bi-stability of plasma with a huge hysteresis loop has been observed in inductive plasma discharges. Despite long plasma research, how this plasma hysteresis occurs remains an unresolved question in plasma physics. Here, we report theory, experiment, and modeling of the hysteresis. It was found experimentally and theoretically that evolution of the electron energy distribution (EED) makes a strong plasma hysteresis. In Ramsauer and non-Ramsauer gas experiments, it was revealed that the plasma hysteresis is observed only at high pressure Ramsauer gas where the EED deviates considerably from a Maxwellian shape. This hysteresis was presented in the plasma balance model where the EED is considered. Because electrons in plasmas are usually not in a thermal equilibrium, this EED-effect can be regarded as a universal phenomenon in plasma physics. PMID:26482650

  3. Effect of Electron Energy Distribution on the Hysteresis of Plasma Discharge: Theory, Experiment, and Modeling

    NASA Astrophysics Data System (ADS)

    Lee, Hyo-Chang; Chung, Chin-Wook

    2015-10-01

    Hysteresis, which is the history dependence of physical systems, is one of the most important topics in physics. Interestingly, bi-stability of plasma with a huge hysteresis loop has been observed in inductive plasma discharges. Despite long plasma research, how this plasma hysteresis occurs remains an unresolved question in plasma physics. Here, we report theory, experiment, and modeling of the hysteresis. It was found experimentally and theoretically that evolution of the electron energy distribution (EED) makes a strong plasma hysteresis. In Ramsauer and non-Ramsauer gas experiments, it was revealed that the plasma hysteresis is observed only at high pressure Ramsauer gas where the EED deviates considerably from a Maxwellian shape. This hysteresis was presented in the plasma balance model where the EED is considered. Because electrons in plasmas are usually not in a thermal equilibrium, this EED-effect can be regarded as a universal phenomenon in plasma physics.

  4. Effect of Electron Energy Distribution on the Hysteresis of Plasma Discharge: Theory, Experiment, and Modeling.

    PubMed

    Lee, Hyo-Chang; Chung, Chin-Wook

    2015-10-20

    Hysteresis, which is the history dependence of physical systems, is one of the most important topics in physics. Interestingly, bi-stability of plasma with a huge hysteresis loop has been observed in inductive plasma discharges. Despite long plasma research, how this plasma hysteresis occurs remains an unresolved question in plasma physics. Here, we report theory, experiment, and modeling of the hysteresis. It was found experimentally and theoretically that evolution of the electron energy distribution (EED) makes a strong plasma hysteresis. In Ramsauer and non-Ramsauer gas experiments, it was revealed that the plasma hysteresis is observed only at high pressure Ramsauer gas where the EED deviates considerably from a Maxwellian shape. This hysteresis was presented in the plasma balance model where the EED is considered. Because electrons in plasmas are usually not in a thermal equilibrium, this EED-effect can be regarded as a universal phenomenon in plasma physics.

  5. Effect of Electron Energy Distribution on the Hysteresis of Plasma Discharge: Theory, Experiment, and Modeling

    NASA Astrophysics Data System (ADS)

    Lee, Hyo-Chang; Chung, Chin-Wook

    2016-09-01

    Hysteresis, which is the history dependence of physical systems, indicates that there are more-than-two stable points in a given condition, and it has been considered to one of the most important topics in fundamental physics. Recently, the hysteresis of plasma has become a focus of research because stable plasma operation is very important for fusion reactors, bio-medical plasmas, and industrial plasmas for nano-device fabrication process. Interestingly, the bi-stability characteristics of plasma with a huge hysteresis loop have been observed in inductive discharge plasmas Because hysteresis study in such plasmas can provide a universal understanding of plasma physics, many researchers have attempted experimental and theoretical studies. Despite long plasma research, how this plasma hysteresis occurs remains an unresolved question in plasma physics. Here, we report theory, experiment, and modeling of the hysteresis. It was found experimentally and theoretically that evolution of the electron energy distribution (EED) makes a strong plasma hysteresis. In Ramsauer and non-Ramsauer gas experiments, it was revealed that the plasma hysteresis is observed only at high pressure Ramsauer gas where the EED deviates considerably from a Maxwellian shape. This hysteresis was presented in the plasma balance model where the EED is considered. Because electrons in plasmas are usually not in a thermal equilibrium, this EED-effect can be regarded as a universal phenomenon in plasma physics. This research was partially supported by Korea Research Institute of Standard and Science.

  6. A suite of user-friendly global climate models: Hysteresis experiments

    NASA Astrophysics Data System (ADS)

    Fraedrich, K.

    2012-05-01

    A hierarchy of global spectral circulation models is introduced ranging from the shallow-water system via the primitive-equation dynamical core of the atmosphere to the Planet Simulator as a Global Climate Model (GCM) of Intermediate Complexity (MIC) which can be used to run climate and paleo-climate simulations for time scales up to ten thousand years or more in an acceptable real time. The priorities in development are set to speed, easy handling and portability with a modular structure suitable for problem-dependent configuration. Adaptions exist for the planetary atmospheres of Mars and of Saturn's moon Titan and are being extended. Common coupling interfaces enable the addition of ocean, ice, vegetation models and more. An interactive mode with a Model Starter and a Graphical User Interface (GUI) is available to select a configuration from the available model suite, to set its parameters and inspect atmospheric fields while changing the models' parameters on the fly. This is especially useful for teaching, debugging and tuning of parameterizations. An updated overview of the model suite's features is presented based on the Earth-like climate model Planet Simulator with mixed-layer ocean introducing static and memory hysteresis in terms of a parameter sweep of the solar constant and CO2 concentrations. The static hysteresis experiment demonstrates that the solar constant varying by 20% reveals warm and snowball Earth climate regimes depending on the history of the system. This hysteresis subjected to a thermodynamic analysis shows the following features: i) Both climate regimes are characterized by global mean surface temperature and entropy growing with increasing solar constant. ii) The climate system's efficiency decreases (increases) with increasing solar constant in present-day warm (snowball) climate conditions. iii) Climate transitions near bifurcation points are characterized by high efficiency associated with the system's large distance from the stable

  7. Studies of earth simulation experiments

    NASA Technical Reports Server (NTRS)

    Hart, J. E.

    1976-01-01

    The low gravity environment of earth orbit offers the potential for performing experiments involving baroclinic Geophysical Fluid Dynamics (GFD) on spherical surfaces. These experiments in turn have the potential for providing deeper understanding of large scale planetary and solar circulations. However, to perform these experiments, one requires an experimental technique whereby a radially directed body force can be generated to simulate a radial gravitational force field. One viable technique is the use of dielectric fluids with temperature dependent dielectric permittivity in a radially directed electric field. Application of the Boussinesq approximation to the equations of motion for this system and restrictions on the size of certain electrodynamic terms in the energy equations yields a set of equations which are analogous to the equations of motions of geophysical systems like the earth's atmosphere on term by term basis. The theoretical design of GFD experiments for performance in earth orbit are described along with results of preliminary tests of a prototype.

  8. Hysteresis and Related Error Mechanisms in the NIST Watt Balance Experiment

    PubMed Central

    Schwarz, Joshua P.; Liu, Ruimin; Newell, David B.; Steiner, Richard L.; Williams, Edwin R.; Smith, Douglas; Erdemir, Ali; Woodford, John

    2001-01-01

    The NIST watt balance experiment is being completely rebuilt after its 1998 determination of the Planck constant. That measurement yielded a result with an approximately 1×10−7 relative standard uncertainty. Because the goal of the new incarnation of the experiment is a ten-fold decrease in uncertainty, it has been necessary to reexamine many sources of systematic error. Hysteresis effects account for a substantial portion of the projected uncertainty budget. They arise from mechanical, magnetic, and thermal sources. The new experiment incorporates several improvements in the apparatus to address these issues, including stiffer components for transferring the mass standard on and off the balance, better servo control of the balance, better pivot materials, and the incorporation of erasing techniques into the mass transfer servo system. We have carried out a series of tests of hysteresis sources on a separate system, and apply their results to the watt apparatus. The studies presented here suggest that our improvements can be expected to reduce hysteresis signals by at least a factor of 10—perhaps as much as a factor of 50—over the 1998 experiment. PMID:27500039

  9. Temperature-Salinity Oscillations, Sudden Transitions, and Hysteresis in Laboratory Experiments and Layered Models

    NASA Astrophysics Data System (ADS)

    Whitehead, J. A.; Te Raa, L.; Tozuka, T.

    2002-12-01

    Simplified box models of the cooling of a salt-stratified ocean have been constructed in the laboratory. A large isothermal basin of water has two layers with differing salinity. Beside this is a small basin connected to the large basin by horizontal tubes at the top, middle and bottom. Calculations indicate that there is a sudden transition and hysteresis between a shallow and a deep convection state if there is a relaxation temperature boundary condition and also if one tube has large flow resistance. Our laboratory studies to date do not clearly show hysteresis but have relatively sudden changes in properties for some parameters. The shallow state is frequently found as an oscillation, and the deep convection state is steady, although thermals produce small rapid fluctuations. Numerical models of the experiments produce qualitative agreement, but quantitative differences are large. In contrast, experiments with a cavity at the bottom of a fresh water reservoir, subjected to steady heating from below and steady salt-water inflow has two distinct states, and exhibits a hysteresis range. Oscillations and transitions like those seen in these experiments may exist in natural bodies with a layer of fresh water cooled from above such as fjords, polar bays, or larger polar regions. The oscillation periods are much greater than either the fresh water or the thermal time scale, making the oscillation mechanism a candidate for climate oscillations. (Much of this work was done at the GFD summer program).

  10. Saturation and hysteresis effects in ionospheric modification experiments observed by the CUTLASS and EISCAT radars

    NASA Astrophysics Data System (ADS)

    Wright, D. M.; Davies, J. A.; Yeoman, T. K.; Robinson, T. R.; Shergill, H.

    2006-03-01

    The results of high latitude ionospheric modification experiments utilising the EISCAT heating facility at Tromsø are presented. As a result of the interaction between the high power pump waves and upper hybrid waves in the ionosphere, field-aligned electron density irregularities are artificially excited. Observations of these structures with the CUTLASS coherent HF radars and the EISCAT incoherent UHF radar exhibit hysteresis effects as the heater output power is varied. These are explained in terms of the two-stage mechanism which leads to the growth of the irregularities. Experiments which involve preconditioning of the ionosphere also indicate that hysteresis could be exploited to maximise the intensity of the field-aligned irregularities, especially where the available heater power is limited.

    In addition, the saturation of the irregularity amplitude is considered. Although, the rate of irregularity growth becomes less rapid at high heater powers it does not seem to fully saturate, indicating that the amplification would continue beyond the capabilities of the Tromsø heater - currently the most powerful of its kind. It is shown that the CUTLASS radars are sensitive to irregularities produced by very low heater powers (effective radiated powers <4 MW). This fact is discussed from the perspective of a new heating facility, SPEAR, located on Spitzbergen and capable of transmitting high frequency radio waves with an effective radiated power ~10% of that of the Tromsø heater (28MW).

  11. Earth Radiation Budget Experiment - Preliminary seasonal results

    NASA Technical Reports Server (NTRS)

    Barkstrom, Bruce R.; Harrison, Edwin F.; Lee, Robert B., III

    1990-01-01

    Data from the Earth Radiation Budget Satellite (ERBS) and from the operational NOAA-9 satellite being placed in the archive of the earth Radiation Budget Experiment (ERBE) are discussed. The results of the ERBE data validation effort are reviewed along with ERBE solar constant observations and earth-viewing results. The latter include monthly average results for July 1985, annual average clear-sky fluxes, and annual average, zonal, and global results.

  12. ``An Earth-Shaking Experience''

    NASA Astrophysics Data System (ADS)

    Achenbach, Joel

    2005-03-01

    Last month's annual meeting of the American Geophysical Union in San Francisco drew an estimated 11,000 scientists, teachers, journalists and geophysics groupies. The schedule of talks could be found in a bound volume as thick as a phone book. You never see a geophysicist in ordinary life, but apparently the world is crawling with them. They came to talk about everything from the ozone layer to the big wad of iron at the center of the Earth. Also about other planets. And magnetic fields. Solar wind. Water on Mars. To be at this convention was to be immersed to the eyebrows in scientific knowledge. It is intellectually fashionable to fetishize the unknown, but at AGU, a person will get the opposite feeling-that science is a voracious, relentless and tireless enterprise, and that soon there may not remain on this Earth an unturned stone.

  13. Hysteresis in Muscle

    NASA Astrophysics Data System (ADS)

    Ramos, Jorgelina; Lynch, Stephen; Jones, David; Degens, Hans

    This paper presents examples of hysteresis from a broad range of scientific disciplines and demonstrates a variety of forms including clockwise, counterclockwise, butterfly, pinched and kiss-and-go, respectively. These examples include mechanical systems made up of springs and dampers which have been the main components of muscle models for nearly one hundred years. For the first time, as far as the authors are aware, hysteresis is demonstrated in single fibre muscle when subjected to both lengthening and shortening periodic contractions. The hysteresis observed in the experiments is of two forms. Without any relaxation at the end of lengthening or shortening, the hysteresis loop is a convex clockwise loop, whereas a concave clockwise hysteresis loop (labeled as kiss-and-go) is formed when the muscle is relaxed at the end of lengthening and shortening. This paper also presents a mathematical model which reproduces the hysteresis curves in the same form as the experimental data.

  14. Earth radiation budget experiment software development

    NASA Technical Reports Server (NTRS)

    Edmonds, W. L.

    1985-01-01

    Computer programming and analysis efforts were carried out in support of the Earth Radiation Budget Experiment (ERBE) at NASA/Langley. The Earth Radiation Budget Experiment is described as well as data acquisition, analysis and modeling support for the testing of ERBE instruments. Also included are descriptions of the programs developed to analyze, format and display data collected during testing of the various ERBE instruments. Listings of the major programs developed under this contract are located in an appendix.

  15. Fatigue Hysteresis Behavior of 2.5D Woven C/SiC Composites: Theory and Experiments

    NASA Astrophysics Data System (ADS)

    Hu, Xuteng; Sun, Zhigang; Yang, Fushu; Chen, Xihui; Song, Yingdong

    2017-02-01

    This paper presents an intriguing fatigue hysteresis behavior of 2.5 dimensional woven C/SiC composites via the integration tool of advanced experimental techniques with a multiscale theoretical model. Tension-tension fatigue experiment has been carried out to predict the fatigue hysteresis properties of 2.5D woven C/SiC composite at room temperature, accompanied with the fracture of specimens to investigate the mechanism of fatigue damage. Meanwhile, a multiscale fatigue model of 2.5D woven C/SiC composites, which encompasses a micro-scale model of fiber/matrix/porosity in fiber tows and a macro-scale model of unit-cell, has been proposed to provide a reliable validation of the experimental results based on fiber damages resulting from relative slip motion with respect to matrix at interfaces and the architecture of 2.5D woven C/SiC composites. The predicted hysteresis loop from theoretical model at room temperature holds great agreement with that from tension-tension fatigue experiments. Also, effects of fatigue load, braided structural parameters and material properties at micro scale on fatigue hysteresis behavior have been investigated.

  16. Hysteresis in a light bulb: connecting electricity and thermodynamics with simple experiments and simulations

    NASA Astrophysics Data System (ADS)

    Clauss, D. A.; Ralich, R. M.; Ramsier, R. D.

    2001-07-01

    A method for integrating energy conversion phenomena, nonlinear circuit behaviour and hysteresis into a simple laboratory activity is demonstrated. Current-voltage data for a flashlight bulb driven at various frequencies and amplitudes are measured and simulated. Non-ohmic behaviour and hysteresis are observed experimentally and reproduced numerically with a model that includes the temperature-dependent specific heat capacity and electrical resistivity of the filament. The phenomenological model and simple experimental design could be modified for a variety of audiences.

  17. The Earth Radiation Budget Experiment nonscanner instrument

    NASA Technical Reports Server (NTRS)

    Luther, M. R.; Cooper, J. E.; Taylor, G. R.

    1986-01-01

    Two Earth Radiation Budget Experiment (ERBE) nonscanner instruments are flying with companion scanner instruments to measure the earth's energy budget from low earth orbit. A third set of instruments will be launched in March 1986. This program is the first designed to make a comprehensive set of highly accurate measurements of the earth's energy budget on the spectral, spatial, and temporal scales specified by the scientific community for use in climatological research. The ERBE nonscanner combines the use of the highly accurate active cavity radiometer (ACR) detector with a comprehensive preflight calibration and characterization program and a design which includes operational flexibility and in-flight calibration checks to achieve and maintain, throughout its 2-year design life, a measurement accuracy capability not previously possible. This paper describes the ERBE nonscanner instrument, its operation, calibration, and mission profile.

  18. Earth environment and Closed Ecology Experiment Facilities.

    PubMed

    Nitta, K

    1994-07-01

    The Closed Ecology Experiment Facilities, CEEF, one of the Environmental Time Machine, is now planning to be constructed in the northern part of Japan with an eye to study the effect of atomic power industries on the local environment. This CEEF can be used not only for investigating the environmental problems related with atomic power industries but also for various environmental problems such as the habitation in lunar & Mars bases and the development of mathematical model to predict the change and change rate of earth parameters. Researches on earth environment and earth system science are discussed with use of CEEF. Preliminary experiments using a small growth chamber showed different results from those estimated by Simple Biosphere Model being used in the climate estimation.

  19. Earth Radiation Budget Experiment - Preliminary seasonal results

    NASA Technical Reports Server (NTRS)

    Barkstrom, Bruce R.; Harrison, Edwin F.; Lee, Robert B., III

    1990-01-01

    Over the previous four years the Earth Radiation Budget Experiment (ERBE) instruments have been gathering data on two satellites, the Earth Radiation Budget Satellite and the the operational NOAA-9 satellite. The ERBE science team recently completed the validation of an initial sampling of these data involving intensive examination of data in four months during 1985 and 1986. The data being placed in the National Space Science Data Center to acquaint the scientific community with their availability are discussed. The ERBE archival data products are also presented.

  20. Earth observations and photography experiment MA-136

    NASA Technical Reports Server (NTRS)

    El-Baz, F.; Mitchell, D. A.

    1976-01-01

    The primary objectives of the earth observations and photography experiment of the Apollo Soyuz Test Project were to photograph various terrestrial structures and to use the capabilities of man as a trained observer in visually studying earth features and phenomena. Man's special capabilities include the sensitivity of the eye to subtle color variations and the speed with which the eye/brain system can interpret what is seen and select targets for photography. Real time astronaut observations constitute a useful complement to orbital photographs and greatly aid in their interpretation. Targets for mapping and hand held photography were selected on the basis of their value to specialists in the earth sciences including geology, oceanography, desert study, hydrology, meteorology, and environmental science.

  1. Earth Observations: Experiences from Various Communication Strategies

    NASA Astrophysics Data System (ADS)

    Lilja Bye, Bente

    2015-04-01

    With Earth observations and the Group of Earth Observations as the common thread, a variety of communication strategies have been applied showcasing the use of Earth observations in geosciences such as climate change, natural hazards, hydrology and more. Based on the experiences from these communication strategies, using communication channels ranging from popular articles in established media, video production, event-based material and social media, lessons have been learned both with respect to the need of capacity, skills, networks, and resources. In general it is not difficult to mobilize geoscientists willing to spend some time on outreach activities. Time for preparing and training is however scarce among scientists. In addition, resources to cover the various aspects of professional science outreach is far from abundant. Among the challenges is the connection between the scientific networks and media channels. Social media competence and capacity are also issues that needs to be addressed more explicitly and efficiently. An overview of the experiences from several types of outreach activities will be given along with some input on possible steps towards improved communication strategies. Steady development of science communication strategies continuously integrating trainging of scientists in use of new outreach tools such as web technology and social innovations for more efficient use of limited resources will remain an issue for the scientific community.

  2. Inverted hysteresis loops in magnetically coupled bilayers with uniaxial competing anisotropies: Theory and experiments

    NASA Astrophysics Data System (ADS)

    Valvidares, S. M.; Álvarez-Prado, L. M.; Martín, J. I.; Alameda, J. M.

    2001-10-01

    The magnetization reversal processes in magnetic bilayers with individual uniaxial anisotropies have been studied, both theoretically and experimentally, to analyze the possible existence of inverted hysteresis loops, that is, with negative remanent magnetization (Mr). Kerr effect measurements in amorphous YCo2/YCo2 bilayers and alternating gradient magnetometry in polycrystalline FeNi/FeNi samples reveal that Mr<0 can be observed for certain directions of the applied magnetic field in the sample plane. This property has also been found in CoNbZr films annealed under an applied field. Our theoretical approach shows that the behavior of these magnetic heterogeneous systems with two coupled uniaxial anisotropies can be understood in terms of two competing effective anisotropies, one biaxial (with Kbiax) and one uniaxial (with Kuniax). In particular, a phase diagram has been deduced for the conditions on Kbiax and Kuniax that can produce negative remanence. This description indicates that, under those anisotropy conditions, inverted hysteresis loops can be observed for an applied field close to the hard axis of the effective uniaxial anisotropy, when magnetization reversal is driven by rotations and not by domain nucleation and wall movement. To consider the real situation in a YCo2/YCo2 bilayer sample, the predictions of this phenomenological model have been further improved by micromagnetic calculations, which are in very good agreement with the magneto-optical measurements.

  3. The Earth's velocity for direct detection experiments

    SciTech Connect

    McCabe, Christopher

    2014-02-01

    The Earth's velocity relative to the Sun in galactic coordinates is required in the rate calculation for direct detection experiments. We provide a rigorous derivation of this quantity to first order in the eccentricity of the Earth's orbit. We also discuss the effect of the precession of the equinoxes, which has hitherto received little explicit discussion. Comparing with other expressions in the literature, we confirm that the expression of Lee, Lisanti and Safdi is correct, while the expression of Lewin and Smith, the de facto standard expression, contains an error. For calculations of the absolute event rate, the leading order expression is sufficient while for modulation searches, an expression with the eccentricity is required for accurate predictions of the modulation phase.

  4. Parity Violation Experiments with Rare Earth Atoms

    NASA Astrophysics Data System (ADS)

    Budker, Dmitry

    1997-10-01

    Since the first suggestions (V. A. Dzuba, V. V. Flambaum, and I. B. Khriplovich, Z. Phys. D1, 243 (1986).), (A. Gongora and P. G. H. Sandars, J. Phys. B 19, L291 (1986).) to search for parity violation in the rare earth atoms, experiments have been carried out by groups in Novosibirsk, Oxford, Hiroshima and Berkeley with Sm, Yb and Dy. The status of these experiments will be reviewed, with some details given on recent Berkeley Dy results ( A.-T. Nguyen, D. Budker, D. DeMille, and M. Zolotorev, Submitted to Phys. Rev. A.). Progress of the Berkeley Yb experiment ( D. DeMille, Phys. Rev. Lett. 74, 4165 (1995).), ( C.J. Bowers, D. Budker, E.D. Commins, D. DeMille, S.J. Freedman, A.-T. Nguyen, S.-Q. Shang, and M. Zolotorev, Phys. Rev. A 53, 3103-9(1996). ) will be described elsewhere at this meeting by C. J. Bowers et al.

  5. Nimbus-6 earth radiation budget experiment.

    PubMed

    Smith, W L; Hickey, J; Howell, H B; Jacobowitz, H; Hilleary, D T; Drummond, A J

    1977-02-01

    This paper describes the Nimbus-6 earth radiation budget experiment including its prelaunch calibration and in-flight performance. A preliminary assessment of the data shows the ERB measurement of the solar constant to be 1392 W/m(2) which is 1.6% higher than the expected value of 1370 W/m(2). Both values are traceable to the cavity radiometer scale. There is a disagreement between the fixed wide-angle and scanning narrow-angle measurements of planetary outgoing longwave radiation flux. Since the scanning channels are calibrated in-flight and show good agreement with previous observations of the Nimbus-3 satellite, the discrepancy is believed to be due to erroneous wide-angle flux estimates. The erroneous estimates may be caused by the misinterpretation of the transfer function for the wide-angle-earth-flux sensing thermopile detectors when viewing the earth which, unlike the prelaunch calibration source, does not fill the field of view of the detector and is not an isotropic radiation source. A field of view factor for the wide-angle channels is determined using an in-flight calibration procedure using the night-time scanning channel longwave radiation flux measurements as the absolute standard. The planetary global albedoes, longwave radiation fluxes, and net radiation are about 30%, 240 W/m(2), and -4 W/m(2) for the months of July and August 1975, which is in good agreement with previous Nimbus-3 estimates.

  6. Earth Radiation Budget Experiment (ERBE) validation

    NASA Technical Reports Server (NTRS)

    Barkstrom, Bruce R.; Harrison, Edwin F.; Smith, G. Louis; Green, Richard N.; Kibler, James F.; Cess, Robert D.

    1990-01-01

    During the past 4 years, data from the Earth Radiation Budget Experiment (ERBE) have been undergoing detailed examination. There is no direct source of groundtruth for the radiation budget. Thus, this validation effort has had to rely heavily upon intercomparisons between different types of measurements. The ERBE SCIENCE Team chose 10 measures of agreement as validation criteria. Late in August 1988, the Team agreed that the data met these conditions. As a result, the final, monthly averaged data products are being archived. These products, their validation, and some results for January 1986 are described. Information is provided on obtaining the data from the archive.

  7. Hysteresis and drift of spiral waves near heterogeneities: From chemical experiments to cardiac simulations

    NASA Astrophysics Data System (ADS)

    Nakouzi, Elias; Totz, Jan Frederik; Zhang, Zhihui; Steinbock, Oliver; Engel, Harald

    2016-02-01

    Dissipative patterns in excitable reaction-diffusion systems can be strongly affected by spatial heterogeneities. Using the photosensitive Belousov-Zhabotinsky reaction, we show a hysteresis effect in the transition between free and pinned spiral rotation. The latter state involves the rotation around a disk-shaped obstacle with an impermeable and inert boundary. The transition is controlled by changes in light intensity. For permeable heterogeneities of higher excitability, we observe spiral drift along both linear and circular boundaries. Our results confirm recent theoretical predictions and, in the case of spiral drift, are further reproduced by numerical simulations with a modified Oregonator model. Additional simulations with a cardiac model show that orbital motion can also exist in anisotropic and three-dimensional systems.

  8. Hysteresis and drift of spiral waves near heterogeneities: From chemical experiments to cardiac simulations.

    PubMed

    Nakouzi, Elias; Totz, Jan Frederik; Zhang, Zhihui; Steinbock, Oliver; Engel, Harald

    2016-02-01

    Dissipative patterns in excitable reaction-diffusion systems can be strongly affected by spatial heterogeneities. Using the photosensitive Belousov-Zhabotinsky reaction, we show a hysteresis effect in the transition between free and pinned spiral rotation. The latter state involves the rotation around a disk-shaped obstacle with an impermeable and inert boundary. The transition is controlled by changes in light intensity. For permeable heterogeneities of higher excitability, we observe spiral drift along both linear and circular boundaries. Our results confirm recent theoretical predictions and, in the case of spiral drift, are further reproduced by numerical simulations with a modified Oregonator model. Additional simulations with a cardiac model show that orbital motion can also exist in anisotropic and three-dimensional systems.

  9. Virtual Synchrotron Experiments for Deep Earth Studies

    NASA Astrophysics Data System (ADS)

    Jackson, J. M.; Alp, E.; Alatas, A.; Zhao, J.; Sturhahn, W.

    2010-12-01

    National facilities offer one-of-a-kind opportunities to apply state-of-the-art experimental techniques to the pressing scientific problems of today. Yet, few students are able to experience research projects at national facilities due to limited accessibility caused in part by limited involvement in the local academic institution, constrained working areas at the experimental stations, and/or travel costs. We present a virtual beam-line for deep Earth mineral physics studies using nuclear resonant and inelastic x-ray scattering methods at Sector 3 of the Advanced Photon Source at Argonne National Laboratory. Off-site students have the capability of controlling their measurements via secure internet connections and webcams. Students can access a 'view only mode' for ease of interaction and safety-control. More experienced users have exclusive control of the experiment and can remotely change variables within the experimental setup.

  10. Virtual synchrotron experiments for deep Earth studies

    NASA Astrophysics Data System (ADS)

    Jackson, J. M.; Alp, E. E.; Zhao, J.; Alatas, A.; Sturhahn, W.

    2011-12-01

    National facilities offer one-of-a-kind opportunities to apply state-of-the-art experimental techniques to the pressing scientific problems of today. Yet, few students are able to experience research projects at national facilities due to limited accessibility caused in part by limited involvement in the local academic institution, constrained working areas at the experimental stations, and/or travel costs. We present a virtual and remote beam-line for deep Earth mineral physics studies using nuclear resonant and inelastic x-ray scattering methods at Sector 3 of the Advanced Photon Source at Argonne National Laboratory. Off-site students have the capability of controlling their measurements via secure internet connections and webcams. Students can access a 'view only mode' for ease of interaction and safety-control. More experienced users have exclusive control of the experiment and can remotely change variables within the experimental setup.

  11. Earth to Orbit Beamed Energy Experiment

    NASA Technical Reports Server (NTRS)

    Johnson, Les; Montgomery, Edward E.

    2017-01-01

    As a means of primary propulsion, beamed energy propulsion offers the benefit of offloading much of the propulsion system mass from the vehicle, increasing its potential performance and freeing it from the constraints of the rocket equation. For interstellar missions, beamed energy propulsion is arguably the most viable in the near- to mid-term. A near-term demonstration showing the feasibility of beamed energy propulsion is necessary and, fortunately, feasible using existing technologies. Key enabling technologies are large area, low mass spacecraft and efficient and safe high power laser systems capable of long distance propagation. NASA is currently developing the spacecraft technology through the Near Earth Asteroid Scout solar sail mission and has signed agreements with the Planetary Society to study the feasibility of precursor laser propulsion experiments using their LightSail-2 solar sail spacecraft. The capabilities of Space Situational Awareness assets and the advanced analytical tools available for fine resolution orbit determination now make it possible to investigate the practicalities of an Earth-to-orbit Beamed Energy eXperiment (EBEX) - a demonstration at delivered power levels that only illuminate a spacecraft without causing damage to it. The degree to which this can be expected to produce a measurable change in the orbit of a low ballistic coefficient spacecraft is investigated. Key system characteristics and estimated performance are derived for a near term mission opportunity involving the LightSail-2 spacecraft and laser power levels modest in comparison to those proposed previously. While the technology demonstrated by such an experiment is not sufficient to enable an interstellar precursor mission, if approved, then it would be the next step toward that goal.

  12. Hysteresis in a superfluid atom circuit

    SciTech Connect

    Song, Tieling; Zhou, D.L.

    2016-09-15

    We study a hysteresis phenomenon in a rotating BEC with a weak link in a quasi-one-dimensional torus by proposing a microscopic theoretical model including a dissipation bath. By analyzing the role of dissipation and the decay rates of all the energy levels, we are able to give a microscopic interpretation of hysteresis recently observed in the experiment and confirm that the hysteresis is the result of the presence of metastable state. In particular, we obtain the hysteresis loops in a quench process just as that in the experiment. We also find that the shape and size of the hysteresis loop change drastically with the strength of the link.

  13. Patterns in Crew-Initiated Photography of Earth from ISS - Is Earth Observation a Salutogenic Experience?

    NASA Technical Reports Server (NTRS)

    Robinson, Julie A.; Slack, Kelley; Olson, V.; Trenchard, M.; Willis, K.; Baskin, P.

    2006-01-01

    This viewgraph presentation asks the question "Is the observation of earth from the ISS a positive (salutogenic) experience for crew members?"All images are distributed to the public via the "Gateway to Astronaut Photography of Earth at http://eol.jsc.nasa.gov. The objectives of the study are (1) Mine the dataset of Earth Observation photography--What can it tell us about the importance of viewing the Earth as a positive experience for the crewmembers? (2) Quantify extent to which photography was self-initiated (not requested by scientists) (3) Identify patterns photography activities versus scientific requested photography.

  14. Skylab experiments. Volume 2: Remote sensing of earth resources

    NASA Technical Reports Server (NTRS)

    1973-01-01

    This volume covers the broad area of earth resources in which Skylab experiments will be performed. A brief description of the Skylab program, its objectives, and vehicles is included. Section 1 introduces the concept and historical significance of remote sensing, and discusses the major scientific considerations involved in remotely sensing the earth's resources. Sections 2 through 6 provide a description of the individual earth resource sensors and experiments to be performed. Each description includes a discussion of the experiment background and scientific objectives, the equipment involved, and a discussion of significant experiment performance areas.

  15. [Mathematical models of hysteresis

    SciTech Connect

    Mayergoyz, I.D.

    1991-01-01

    The research described in this proposal is currently being supported by the US Department of Energy under the contract Mathematical Models of Hysteresis''. Thus, before discussing the proposed research in detail, it is worthwhile to describe and summarize the main results achieved in the course of our work under the above contract. Our ongoing research has largely been focused on the development of mathematical models of hysteretic nonlinearities with nonlocal memories''. The distinct feature of these nonlinearities is that their current states depend on past histories of input variations. It turns out that memories of hysteretic nonlinearities are quite selective. Indeed, experiments show that only some past input extrema leave their marks upon future states of hysteretic nonlinearities. Thus special mathematical tools are needed in order to describe nonlocal selective memories of hysteretic nonlinearities. Our research has been primarily concerned with Preisach-type models of hysteresis. All these models have a common generic feature; they are constructed as superpositions of simplest hysteretic nonlinearities-rectangular loops. Our study has by and large been centered around the following topics: various generalizations and extensions of the classical Preisach model, finding of necessary and sufficient conditions for the representation of actual hysteretic nonlinearities by various Preisach type models, solution of identification problems for these models, numerical implementation and experimental testing of Preisach type models. Although the study of Preisach type models has constituted the main direction of the research, some effort has also been made to establish some interesting connections between these models and such topics as: the critical state model for superconducting hysteresis, the classical Stoner-Wohlfarth model of vector magnetic hysteresis, thermal activation type models for viscosity, magnetostrictive hysteresis and neural networks.

  16. Clouds and the Earth's Radiant Energy System (CERES) experiment

    NASA Technical Reports Server (NTRS)

    Cooper, John E.; Barkstrom, Bruce R.; Kopia, Leonard P.

    1992-01-01

    The Clouds and the Earth's Radiant Energy System (CERES) experiment will play a major role in NASA's planned multi-instrument multi-satellite Earth Observing System (EOS) program to observe and study the total Earth System on a global scale. The CERES experiment will provide EOS with a consistent data base of accurately known fields of radiation and of clouds; and will investigate the important question of the impact of clouds upon the radiative energy flow through the earth-atmosphere system. The CERES instruments will be an improved version of the Earth Radiation Budget Experiment (ERBE) broadband scanning radiometer instruments flown by NASA in the 1980s. This paper describes the CERES experiment approach and the current CERES instrument design status.

  17. Clouds and the Earth's Radiant Energy System (CERES) experiment

    NASA Technical Reports Server (NTRS)

    Cooper, John E.; Barkstrom, Bruce R.; Kopia, Leonard P.

    1992-01-01

    The Clouds and the Earth's Radiant Energy System (CERES) experiment will play a major role in NASA's planned multi-instrument multi-satellite Earth Observing System (EOS) program to observe and study the total Earth System on a global scale. The CERES experiment will provide EOS with a consistent data base of accurately known fields of radiation and of clouds; and will investigate the important question of the impact of clouds upon the radiative energy flow through the earth-atmosphere system. The CERES instruments will be an improved version of the Earth Radiation Budget Experiment (ERBE) broadband scanning radiometer instruments flown by NASA in the 1980s. This paper describes the CERES experiment approach and the current CERES instrument design status.

  18. Mach stem hysteresis: Experiments addressing a novel explanation of clumpy astrophysical jet emission

    NASA Astrophysics Data System (ADS)

    Yirak, K.; Foster, J. M.; Hartigan, P.; Wilde, B. H.; Douglas, M. R.; Paguio, R.; Blue, B. E.; Martinez, D.; Farley, D.; Rosen, P. A.; Frank, A.

    2013-06-01

    Recent time-series observations of shock waves in stellar jets taken with the Hubble Space Telescope reveal localized bright knots that persist over nearly 15 years. While some of these features represent shock fronts caused by variable velocities in the flow, others appear at the intersection points between distinct bow shocks. Theoretically, when the angle between two intersecting shocks exceeds a certain critical value, a third shock (Mach stem) should form. Because Mach stems form perpendicular to the direction of flow, incoming particles encounter a normal shock instead of an oblique one, which results in brighter emission at this location. To study this phenomenon in a controlled laboratory setting, we have carried out experiments on the Omega laser aimed at understanding the formation, growth, and destruction of Mach stems in the warm dense plasma regime. Our experimental results indicate how the growth rate depends upon included angle, and numerical simulations indicate that it may be possible to stabilize an already-formed Mach stem below the critical angle when certain conditions are satisfied.

  19. Developing Authentic Research Experiences Using EarthScope Data

    NASA Astrophysics Data System (ADS)

    Hall-Wallace, M. K.

    2003-12-01

    EarthScope, a decade-long experiment to understand the formation, structure, and evolution of the North American continent, will carry-out active investigations in nearly every county in the US. The excitement of a huge science experiment in one's own backyard piques interest, but teachers need resources and professional development experiences to capitalize upon this excitement and create opportunities for their students' learning. The EarthScope Education and Outreach Network will provide the interface to make EarthScope science, and the advanced technology and modern approaches used to understand Earth, relevant and beneficial to K-16 educators vested in advancing Earth science education. Three obstacles must be overcome for success in carrying out authentic EarthScope research in the classroom. First, scientists and teachers must work together to identify relevant and developmentally appropriate research questions for the target audience. Second, teachers will need professional development experiences that engage them in authentic research and that provide support for introducing a similar research experience in their own classroom. Third, the outcome of the research experience must have value to the scientist, teacher and student to motivate sustained participation by all. The dense array of seismometers being deployed in the USArray component of EarthScope will permit students and the public to see first-hand Earth's dynamic response to both human and natural events in their hometown and around the country. Targeted local experiments will make EarthScope's scientific investigations and discoveries relevant for educational efforts on a region-by-region basis. Combining the real-time seismic data streams from USArray with data and instrumentation from the growing US Educational Seismic Network (USESN) opens up endless possibilities for student-centered research. In this paper, I will discuss the lessons learned from eight years of leading a high school

  20. Observations from the NASA multisatellite Earth Radiation Budget Experiment

    NASA Technical Reports Server (NTRS)

    Harrison, Edwin F.

    1990-01-01

    Satellite measurements from the Earth Radiation Budget Experiment (ERBE) are providing new insights into the earth radiation balance. The ERBE results indicate that clouds have more of a cooling effect than a greenhouse warming effect on the earth-atmosphere system. The largest net-radiation cooling appears over the midlatitude oceans in the summer hemisphere where maximum sunlight and maximum cloud cover occur. The ERBE data also have shown that many areas of the earth exhibit significant diurnal variations in both longwave and shortwave radiation. In order to assess future global climatic changes, a follow-on experiment to ERBE, called Clouds and Earth's Radiant Energy System (CERES), has been selected to fly on the Earth Observing System in the the 1990's.

  1. Observations from the NASA multisatellite Earth Radiation Budget Experiment

    NASA Technical Reports Server (NTRS)

    Harrison, Edwin F.

    1990-01-01

    Satellite measurements from the Earth Radiation Budget Experiment (ERBE) are providing new insights into the earth radiation balance. The ERBE results indicate that clouds have more of a cooling effect than a greenhouse warming effect on the earth-atmosphere system. The largest net-radiation cooling appears over the midlatitude oceans in the summer hemisphere where maximum sunlight and maximum cloud cover occur. The ERBE data also have shown that many areas of the earth exhibit significant diurnal variations in both longwave and shortwave radiation. In order to assess future global climatic changes, a follow-on experiment to ERBE, called Clouds and Earth's Radiant Energy System (CERES), has been selected to fly on the Earth Observing System in the the 1990's.

  2. Celebrating the Earth: Stories, Experiences, and Activities.

    ERIC Educational Resources Information Center

    Livo, Norma J.

    Young learners are invited to learn about the natural world through engaging activities that encourage the observation, exploration, and appreciation of nature. Weaving together a stimulating tapestry of folktales, personal narratives, and hands-on activities, this book teaches children about the earth and all of its creatures--birds, plants,…

  3. Celebrating the Earth: Stories, Experiences, and Activities.

    ERIC Educational Resources Information Center

    Livo, Norma J.

    Young learners are invited to learn about the natural world through engaging activities that encourage the observation, exploration, and appreciation of nature. Weaving together a stimulating tapestry of folktales, personal narratives, and hands-on activities, this book teaches children about the earth and all of its creatures--birds, plants,…

  4. Shock Tube Experiments for Earth and Mars Entry Conditions

    DTIC Science & Technology

    2009-09-01

    RTO-EN-AVT-162 13 - 1 Shock Tube Experiments for Earth and Mars Entry Conditions David W. Bogdanoff ELORET Corporation 465 S. Mathilda...Ave., Suite 103 Sunnyvale, CA 94086 USA David.W.Bogdanoff@nasa.gov ABSTRACT This seminar describes how radiative heating for earth and Mars entry...data acquistion system and representative spectra are presented for earth and Mars entry conditions. 1.0 INTRODUCTION The motivations for the

  5. Radiometric calibrations for the Earth radiation budget experiment.

    PubMed

    Hickey, J R; Karoli, A R

    1974-03-01

    The earth radiation budget (ERB) experiment is scheduled to be flown aboard the NIMBUS F satellite that is to be launched in mid-1974. This experiment includes channels, to measure solar radiation, earth-reflected radiation (albedo), and earth-emitted long-wave radiation. The calibration techniques and the standards employed are included in the topics of this paper. Problems associated with achieving the desired levels of confidence for a multifaceted, high accuracy satellite experiment are discussed and some results of preliminary calibrations are presented.

  6. Hysteresis phenomena in hydraulic measurement

    NASA Astrophysics Data System (ADS)

    Ran, H. J.; Luo, X. W.; Chen, Y. L.; Xu, H. Y.; Farhat, M.

    2012-11-01

    Hysteresis phenomena demonstrate the lag between the generation and the removal of some physical phenomena. This paper studies the hysteresis phenomena of the head-drop in a scaled model pump turbine using experiment test and CFD methods. These lag is induced by complicated flow patterns, which influenced the reliability of rotating machine. Keeping the same measurement procedure is concluded for the hydraulic machine measurement.

  7. Skylab earth resources experiment package /EREP/ - Sea surface topography experiment

    NASA Technical Reports Server (NTRS)

    Vonbun, F. O.; Marsh, J. G.; Mcgoogan, J. T.; Leitao, C. D.; Vincent, S.; Wells, W. T.

    1976-01-01

    The S-193 Skylab radar altimeter was operated in a round-the-world pass on Jan. 31, 1974. The main purpose of this experiment was to test and 'measure' the variation of the sea surface topography using the Goddard Space Flight Center (GSFC) geoid model as a reference. This model is based upon 430,000 satellite and 25,000 ground gravity observations. Variations of the sea surface on the order of -40 to +60 m were observed along this pass. The 'computed' and 'measured' sea surfaces have an rms agreement on the order of 7 m. This is quite satisfactory, considering that this was the first time the sea surface has been observed directly over a distance of nearly 35,000 km and compared to a computed model. The Skylab orbit for this global pass was computed using the Goddard Earth Model (GEM 6) and S-band radar tracking data, resulting in an orbital height uncertainty of better than 5 m over one orbital period.

  8. Apollo experience report: Earth landing system

    NASA Technical Reports Server (NTRS)

    West, R. B.

    1973-01-01

    A brief discussion of the development of the Apollo earth landing system and a functional description of the system are presented in this report. The more significant problems that were encountered during the program, the solutions, and, in general, the knowledge that was gained are discussed in detail. Two appendixes presenting a detailed description of the various system components and a summary of the development and the qualification test programs are included.

  9. Characterizations of the Earth Radiation Budget Experiment (ERBE) scanning radiometers

    NASA Technical Reports Server (NTRS)

    Lee, Robert B., III; Barkstrom, Bruce R.; Avis, Lee M.; Halyo, Nesim; Gibson, Michael A.

    1989-01-01

    NASA's Earth Radiation Budget Experiment employs the Earth Radiation Budget Satellite and the NOAA 9 and 10 spacecraft to obtain absolute measurements of incoming solar radiation, shortwave earth-reflected solar radiation, and longwave earth-emitted radiation, using both scanning and nonscanning radiometers. Each of the three remote-sensing spacecraft carry narrow FOV scanning radiometers whose detection sensors are thermistor bolometers. Attention is presently given to the calibration models and methods employed in characterizing the scanning radiometers' output signals; the design features of the scanners and flight calibration systems are presented.

  10. The Earth is flat when personally significant experiences with the sphericity of the Earth are absent.

    PubMed

    Carbon, Claus-Christian

    2010-07-01

    Participants with personal and without personal experiences with the Earth as a sphere estimated large-scale distances between six cities located on different continents. Cognitive distances were submitted to a specific multidimensional scaling algorithm in the 3D Euclidean space with the constraint that all cities had to lie on the same sphere. A simulation was run that calculated respective 3D configurations of the city positions for a wide range of radii of the proposed sphere. People who had personally experienced the Earth as a sphere, at least once in their lifetime, showed a clear optimal solution of the multidimensional scaling (MDS) routine with a mean radius deviating only 8% from the actual radius of the Earth. In contrast, the calculated configurations for people without any personal experience with the Earth as a sphere were compatible with a cognitive concept of a flat Earth. 2010 Elsevier B.V. All rights reserved.

  11. Magneto-Optical Experiments on Rare Earth Garnet Films.

    ERIC Educational Resources Information Center

    Tanner, B. K.

    1980-01-01

    Describes experiments in which inexpensive or standard laboratory equipment is used to measure several macroscopic magnetic properties of thin rare earth garnet films used in the manufacture of magnetic bubble devices. (Author/CS)

  12. Magneto-Optical Experiments on Rare Earth Garnet Films.

    ERIC Educational Resources Information Center

    Tanner, B. K.

    1980-01-01

    Describes experiments in which inexpensive or standard laboratory equipment is used to measure several macroscopic magnetic properties of thin rare earth garnet films used in the manufacture of magnetic bubble devices. (Author/CS)

  13. The magnetization process: Hysteresis

    NASA Technical Reports Server (NTRS)

    Balsamel, Richard

    1990-01-01

    The magnetization process, hysteresis (the difference in the path of magnetization for an increasing and decreasing magnetic field), hysteresis loops, and hard magnetic materials are discussed. The fabrication of classroom projects for demonstrating hysteresis and the hysteresis of common magnetic materials is described in detail.

  14. Passive exposure of Earth radiation budget experiment components (A0147)

    NASA Technical Reports Server (NTRS)

    Hickey, J. R.; Griffin, F. J.

    1984-01-01

    In-flight calibration for the solr and Earth flux channels was examined. Earth Radiation on Budget (ERB) channel components were exposed to the space environment and then retrieved and resubmitted to radiometric calibration after exposure. It is suggested that corrections may be applied to ERB results and information will be obtained to aid in the selection of components for future operational solar and Earth radiation budget experiments. To assure that these high accuracy devices are measuring real variations and are not responding to changes induced by the space environment, it is desirable to test such devices radiometrically after exposure to the best approximation of the orbital environment.

  15. Passive exposure of Earth radiation budget experiment components (A0147)

    NASA Astrophysics Data System (ADS)

    Hickey, J. R.; Griffin, F. J.

    1984-02-01

    In-flight calibration for the solr and Earth flux channels was examined. Earth Radiation on Budget (ERB) channel components were exposed to the space environment and then retrieved and resubmitted to radiometric calibration after exposure. It is suggested that corrections may be applied to ERB results and information will be obtained to aid in the selection of components for future operational solar and Earth radiation budget experiments. To assure that these high accuracy devices are measuring real variations and are not responding to changes induced by the space environment, it is desirable to test such devices radiometrically after exposure to the best approximation of the orbital environment.

  16. Earth Radiation Budget Experiment (ERBE) scanner instrument anomaly investigation

    NASA Technical Reports Server (NTRS)

    Watson, N. D.; Miller, J. B.; Taylor, L. V.; Lovell, J. B.; Cox, J. W.; Fedors, J. C.; Kopia, L. P.; Holloway, R. M.; Bradley, O. H.

    1985-01-01

    The results of an ad-hoc committee investigation of in-Earth orbit operational anomalies noted on two identical Earth Radiation Budget Experiment (ERBE) Scanner instruments on two different spacecraft busses is presented. The anomalies are attributed to the bearings and the lubrication scheme for the bearings. A detailed discussion of the pertinent instrument operations, the approach of the investigation team and the current status of the instruments now in Earth orbit is included. The team considered operational changes for these instruments, rework possibilities for the one instrument which is waiting to be launched, and preferable lubrication considerations for specific space operational requirements similar to those for the ERBE scanner bearings.

  17. Earth Sciences Requirements for the Information Sciences Experiment System

    NASA Technical Reports Server (NTRS)

    Bowker, David E. (Editor); Katzberg, Steve J. (Editor); Wilson, R. Gale (Editor)

    1990-01-01

    The purpose of the workshop was to further explore and define the earth sciences requirements for the Information Sciences Experiment System (ISES), a proposed onboard data processor with real-time communications capability intended to support the Earth Observing System (Eos). A review of representative Eos instrument types is given and a preliminary set of real-time data needs has been established. An executive summary is included.

  18. Modeling of hysteresis in gene regulatory networks.

    PubMed

    Hu, J; Qin, K R; Xiang, C; Lee, T H

    2012-08-01

    Hysteresis, observed in many gene regulatory networks, has a pivotal impact on biological systems, which enhances the robustness of cell functions. In this paper, a general model is proposed to describe the hysteretic gene regulatory network by combining the hysteresis component and the transient dynamics. The Bouc-Wen hysteresis model is modified to describe the hysteresis component in the mammalian gene regulatory networks. Rigorous mathematical analysis on the dynamical properties of the model is presented to ensure the bounded-input-bounded-output (BIBO) stability and demonstrates that the original Bouc-Wen model can only generate a clockwise hysteresis loop while the modified model can describe both clockwise and counter clockwise hysteresis loops. Simulation studies have shown that the hysteresis loops from our model are consistent with the experimental observations in three mammalian gene regulatory networks and two E.coli gene regulatory networks, which demonstrate the ability and accuracy of the mathematical model to emulate natural gene expression behavior with hysteresis. A comparison study has also been conducted to show that this model fits the experiment data significantly better than previous ones in the literature. The successful modeling of the hysteresis in all the five hysteretic gene regulatory networks suggests that the new model has the potential to be a unified framework for modeling hysteresis in gene regulatory networks and provide better understanding of the general mechanism that drives the hysteretic function.

  19. An experience of science theatre: Earth Science for children

    NASA Astrophysics Data System (ADS)

    Musacchio, Gemma; Lanza, Tiziana; D'Addezio, Giuliana

    2015-04-01

    The present paper describes an experience of science theatre addressed to children of primary and secondary school, with the main purpose of explaining the Earth interior while raising awareness about natural hazard. We conducted the experience with the help of a theatrical company specialized in shows for children. Several performances have been reiterated in different context, giving us the opportunity of conducting a preliminary survey with public of different ages, even if the show was conceived for children. Results suggest that science theatre while relying on creativity and emotional learning in transmitting knowledge about the Earth and its hazard has the potential to induce in children a positive attitude towards the risks

  20. Return of target material ions leads to a reduced hysteresis in reactive high power impulse magnetron sputtering: Experiment

    NASA Astrophysics Data System (ADS)

    Čapek, Jiří; Kadlec, Stanislav

    2017-05-01

    Titanium and aluminum targets have been reactively sputtered in Ar +O2 or Ar +N2 gas mixtures in order to systematically investigate the effect of reduced hysteresis in reactive high power impulse magnetron sputtering (HiPIMS) as compared to other sputtering techniques utilizing low discharge target power density (e.g., direct current or pulsed direct current mid-frequency magnetron sputtering) operated at the same average discharge power. We found that the negative slope of the flow rate of the reactive gas gettered by the sputtered target material as a function of the reactive gas partial pressure is clearly lower in the case of HiPIMS. This results in a lower critical pumping speed, which implies a reduced hysteresis. We argue that the most important effect explaining the observed behavior is covering of the reacted areas of the target by the returning ionized metal, effectively lowering the target coverage at a given partial pressure. This explanation is supported by a calculation using an analytical model of reactive HiPIMS with time and space averaging (developed by us).

  1. The Earth Is Flat when Personally Significant Experiences with the Sphericity of the Earth Are Absent

    ERIC Educational Resources Information Center

    Carbon, Claus-Christian

    2010-01-01

    Participants with personal and without personal experiences with the Earth as a sphere estimated large-scale distances between six cities located on different continents. Cognitive distances were submitted to a specific multidimensional scaling algorithm in the 3D Euclidean space with the constraint that all cities had to lie on the same sphere. A…

  2. The Earth Is Flat when Personally Significant Experiences with the Sphericity of the Earth Are Absent

    ERIC Educational Resources Information Center

    Carbon, Claus-Christian

    2010-01-01

    Participants with personal and without personal experiences with the Earth as a sphere estimated large-scale distances between six cities located on different continents. Cognitive distances were submitted to a specific multidimensional scaling algorithm in the 3D Euclidean space with the constraint that all cities had to lie on the same sphere. A…

  3. Hysteresis in the phase transition of chocolate

    NASA Astrophysics Data System (ADS)

    Ren, Ruilong; Lu, Qunfeng; Lin, Sihua; Dong, Xiaoyan; Fu, Hao; Wu, Shaoyi; Wu, Minghe; Teng, Baohua

    2016-01-01

    We designed an experiment to reproduce the hysteresis phenomenon of chocolate appearing in the heating and cooling process, and then established a model to relate the solidification degree to the order parameter. Based on the Landau-Devonshire theory, our model gave a description of the hysteresis phenomenon in chocolate, which lays the foundations for the study of the phase transition behavior of chocolate.

  4. Skylab Experiments, Volume 2, Remote Sensing of Earth Resources.

    ERIC Educational Resources Information Center

    National Aeronautics and Space Administration, Washington, DC.

    Up-to-date knowledge about Skylab experiments is presented for the purpose of informing high school teachers about scientific research performed in orbit and enabling them to broaden their scope of material selection. The second volume emphasizes the sensing of earth resources. The content includes an introduction to the concept and historical…

  5. NASA's Earth Science Data Systems Standards Process Experiences

    NASA Technical Reports Server (NTRS)

    Ullman, Richard E.; Enloe, Yonsook

    2007-01-01

    NASA has impaneled several internal working groups to provide recommendations to NASA management on ways to evolve and improve Earth Science Data Systems. One of these working groups is the Standards Process Group (SPC). The SPG is drawn from NASA-funded Earth Science Data Systems stakeholders, and it directs a process of community review and evaluation of proposed NASA standards. The working group's goal is to promote interoperability and interuse of NASA Earth Science data through broader use of standards that have proven implementation and operational benefit to NASA Earth science by facilitating the NASA management endorsement of proposed standards. The SPC now has two years of experience with this approach to identification of standards. We will discuss real examples of the different types of candidate standards that have been proposed to NASA's Standards Process Group such as OPeNDAP's Data Access Protocol, the Hierarchical Data Format, and Open Geospatial Consortium's Web Map Server. Each of the three types of proposals requires a different sort of criteria for understanding the broad concepts of "proven implementation" and "operational benefit" in the context of NASA Earth Science data systems. We will discuss how our Standards Process has evolved with our experiences with the three candidate standards.

  6. Performance of the cometary experiment MUPUS on the body Earth

    NASA Astrophysics Data System (ADS)

    Marczewski, W.; Usowicz, B.; Schröer, K.; Seiferlin, K.; Spohn, T.

    2003-04-01

    Thermal experiment MUPUS for the Rosetta mission was extensively experience in field and laboratory conditions to predict its performance under physical processes available on the Earth. The goal was not guessing a cometary material in the ground but available behavior of thermal sensor responses monitoring mass and energy transfer. The processes expected on a comet are different in composition and environmental from those met on the Earth but basically similar in physics. Nature of energy powering the processes is also essentially the same - solar radiation. Several simple laboratory experiments with freezing and thawing with water ice, with mixture of water and oil and water layers strongly diverged by salinity revealed capability of recognition layered structure of the medium under test. More over effects of slow convection and latent heat related to the layers are also observed well. Cometary environment without atmosphere makes process of sublimation dominant. Open air conditions on the Earth may also offer a change of state in matter but between different phases. Learning temperature gradient in snow layers under thawing show that effects stimulated by a cause of daily cycling may be detected thermally. Results from investigations in snow made on Spitzbergen are good proofs on capability of the method. Relevance of thermal effects to heat powered processes of mass transport in the matter of ground is meaningful for the cometary experiment of MUPUS and for Earth sciences much concerned on water, gas and solid matter transport in the terrestrial ground. Results leading to energy balance studied on the Earth surface may be interesting also for the experiment on the comet and are to be discussed.

  7. Flagstaff, Arizona seen in Earth Resources Experiments package

    NASA Technical Reports Server (NTRS)

    1974-01-01

    A spectacular winter view of the Flagstaff, Arizona area is seen in this Skylab 4 Earth Resources Experiments package S190-B (five-inch earth terrain camera) infrared photograph taken from the Skylab space station in Earth orbit. Included in the scene are the San Francisco Mountains, Oak Creek Canyon, Painted Desert and Meteor Crater. The infrared picture depicts in red living vegetation, in white the snow, and in bright blue the water. Major features identified in this photograph are Humphrey's peak, top center, Flagstaff at foot of the peak, Sunset Crater volcanic field with numerous vents and craters right of Flagstaff and Meteor Crater (right center). Within the mountainous areas several clear areas generally rectangular are visible and represent the areas where lumbering has removed the forest. The thin white line extending from left corner to Sunset Crater fields is the power transmission line cleared area. Roads are subdued and are not easily visible.

  8. Results from the Earth Radiation Budget Experiment (ERBE)

    NASA Technical Reports Server (NTRS)

    Barkstrom, Bruce R.; Harrison, Edwin F.; Smith, G. Louis; Cess, Robert D.

    1989-01-01

    The Earth Radiation Budget Experiment (ERBE) has been observing the earth during the past 4 years from three satellites. Numerous validation procedures have been applied to the data. Particularly important have been intercomparisons between three channels of scanning radiometers and wide and medium field-of-view radiometers. These intercomparisons and onboard calibration targets have provided assurance of high data quality. In addition to the classic radiation budget parameters: global absorbed and emitted energy, ERBE is producing fluxes on scales of 250 km that can significantly increase understanding of the earth's climate. Of particular interest are ERBE measurements of clear-sky albedos and longwave fluxes, which are part of the ERBE data products. Use of data from the precessing ERBE satellite together with data from the sun-synchronous NOAA-9 and NOAA-10 satellites also provides information on the diurnal cycle of shortwave and longwave fluxes.

  9. Contact angle hysteresis explained.

    PubMed

    Gao, Lichao; McCarthy, Thomas J

    2006-07-04

    A view of contact angle hysteresis from the perspectives of the three-phase contact line and of the kinetics of contact line motion is given. Arguments are made that advancing and receding are discrete events that have different activation energies. That hysteresis can be quantified as an activation energy by the changes in interfacial area is argued. That this is an appropriate way of viewing hysteresis is demonstrated with examples.

  10. The Earth Radiation Budget Experiment - Science and implementation

    NASA Technical Reports Server (NTRS)

    Barkstrom, B. R.; Smith, G. L.

    1986-01-01

    This paper gives an overview of the Earth Radiation Budget Experiment. The experiment consists of scanning and nonscanning radiometer packages on three spacecraft. One is a satellite with a 57 deg, inclination orbit which precesses around the earth once every 2 months. Packages are also flown on the sun-synchronous NOAA-F and NOAA-G operational meteorological satellites. The scanning radiometer includes three channels: shortwave, long-wave, and total. The nonscanner package encompasses a pair of wide-field-of-view radiometers and a pair of medium-field-of-view radiometers. Each pair consists of a total and a shortwave radiometer. The scientific importance and objectives of the mission are described, including the need for the three spacecraft and the utility of the complementary types of radiometers.

  11. Mission planning aspects of Skylab Earth Resources Experiment

    NASA Technical Reports Server (NTRS)

    Deatkine, D.

    1973-01-01

    Review of the mission planning techniques that have been developed to optimize the data return from the Earth Resources Experiments Package on Skylab. The techniques are designed to cope with a variety of missions, systems and weather constraints, and sensor development and science applications data requirements. The planning techniques developed for Skylab are applicable to similar later-generation orbital programs, both manned and unmanned.

  12. Large magnetocaloric effect and near-zero thermal hysteresis in the rare earth intermetallic Tb1-x Dy x Co2 compounds

    NASA Astrophysics Data System (ADS)

    Zeng, Yuyang; Tian, Fanghua; Chang, Tieyan; Chen, Kaiyun; Yang, Sen; Cao, Kaiyan; Zhou, Chao; Song, Xiaoping

    2017-02-01

    We report the magnetocaloric effect in a Tb1-x Dy x Co2 compound which exhibits a wide working temperature window around the Curie temperature (T C) and delivers a large refrigerant capacity (RC) with near-zero thermal hysteresis. Specifically, the wide full width at half maxima ({δ\\text{WFHM}} ) can reach up to 62 K and the RC value changes from 216.5 to 274.3 J Kg-1 when the external magnetic field increases to 5 T. Such magnetocaloric effects are attributed to a magnetic and structural transition from a paramagnetic and cubic phase to a ferromagnetic (M S along [1 1 1] direction) and rhombohedral phase or ferromagnetic (M S along [0 0 1] direction) and tetragonal phase.

  13. Clouds and the Earth's Radiant Energy System (CERES): An Earth Observing System Experiment

    NASA Technical Reports Server (NTRS)

    Wielicki, Bruce A.; Barkstrom, Bruce R.; Harrison, Edwin F.; Lee, Robert B., III; Smith, G. Louis; Cooper, John E.

    1996-01-01

    Clouds and the Earth's Radiant Energy System (CERES) is an investigation to examine the role of cloud/radiation feedback in the Earth's climate system. The CERES broadband scanning radiometers are an improved version of the Earth Radiation Budget Experiment (ERBE) radiometers. The CERES instruments will fly on several National Aeronautics and Space Administration Earth Observing System (EOS) satellites starting in 1998 and extending over at least 15 years. The CERES science investigations will provide data to extend the ERBE climate record of top-of-atmosphere shortwave (SW) and longwave (LW) radiative fluxes CERES will also combine simultaneous cloud property data derived using EOS narrowband imagers to provide a consistent set of cloud/radiation data, including SW and LW radiative fluxes at the surface and at several selected levels within the atmosphere. CERES data are expected to provide top-of-atmosphere radiative fluxes with a factor of 2 to 3 less error than the ERBE data Estimates of radiative fluxes at the surface and especially within the atmosphere will be a much greater challenge but should also show significant improvements over current capabilities.

  14. Clouds and the Earth's Radiant Energy System (CERES): An Earth Observing System Experiment

    NASA Technical Reports Server (NTRS)

    Wielicki, Bruce A.; Barkstrom, Bruce R.; Harrison, Edwin F.; Lee, Robert B., III; Smith, G. Louis; Cooper, John E.

    1996-01-01

    Clouds and the Earth's Radiant Energy System (CERES) is an investigation to examine the role of cloud/radiation feedback in the Earth's climate system. The CERES broadband scanning radiometers are an improved version of the Earth Radiation Budget Experiment (ERBE) radiometers. The CERES instruments will fly on several National Aeronautics and Space Administration Earth Observing System (EOS) satellites starting in 1998 and extending over at least 15 years. The CERES science investigations will provide data to extend the ERBE climate record of top-of-atmosphere shortwave (SW) and longwave (LW) radiative fluxes CERES will also combine simultaneous cloud property data derived using EOS narrowband imagers to provide a consistent set of cloud/radiation data, including SW and LW radiative fluxes at the surface and at several selected levels within the atmosphere. CERES data are expected to provide top-of-atmosphere radiative fluxes with a factor of 2 to 3 less error than the ERBE data Estimates of radiative fluxes at the surface and especially within the atmosphere will be a much greater challenge but should also show significant improvements over current capabilities.

  15. Hysteresis in a quantized superfluid 'atomtronic' circuit.

    PubMed

    Eckel, Stephen; Lee, Jeffrey G; Jendrzejewski, Fred; Murray, Noel; Clark, Charles W; Lobb, Christopher J; Phillips, William D; Edwards, Mark; Campbell, Gretchen K

    2014-02-13

    Atomtronics is an emerging interdisciplinary field that seeks to develop new functional methods by creating devices and circuits where ultracold atoms, often superfluids, have a role analogous to that of electrons in electronics. Hysteresis is widely used in electronic circuits-it is routinely observed in superconducting circuits and is essential in radio-frequency superconducting quantum interference devices. Furthermore, it is as fundamental to superfluidity (and superconductivity) as quantized persistent currents, critical velocity and Josephson effects. Nevertheless, despite multiple theoretical predictions, hysteresis has not been previously observed in any superfluid, atomic-gas Bose-Einstein condensate. Here we directly detect hysteresis between quantized circulation states in an atomtronic circuit formed from a ring of superfluid Bose-Einstein condensate obstructed by a rotating weak link (a region of low atomic density). This contrasts with previous experiments on superfluid liquid helium where hysteresis was observed directly in systems in which the quantization of flow could not be observed, and indirectly in systems that showed quantized flow. Our techniques allow us to tune the size of the hysteresis loop and to consider the fundamental excitations that accompany hysteresis. The results suggest that the relevant excitations involved in hysteresis are vortices, and indicate that dissipation has an important role in the dynamics. Controlled hysteresis in atomtronic circuits may prove to be a crucial feature for the development of practical devices, just as it has in electronic circuits such as memories, digital noise filters (for example Schmitt triggers) and magnetometers (for example superconducting quantum interference devices).

  16. Hysteresis in a quantized superfluid `atomtronic' circuit

    NASA Astrophysics Data System (ADS)

    Eckel, Stephen; Lee, Jeffrey G.; Jendrzejewski, Fred; Murray, Noel; Clark, Charles W.; Lobb, Christopher J.; Phillips, William D.; Edwards, Mark; Campbell, Gretchen K.

    2014-02-01

    Atomtronics is an emerging interdisciplinary field that seeks to develop new functional methods by creating devices and circuits where ultracold atoms, often superfluids, have a role analogous to that of electrons in electronics. Hysteresis is widely used in electronic circuits--it is routinely observed in superconducting circuits and is essential in radio-frequency superconducting quantum interference devices. Furthermore, it is as fundamental to superfluidity (and superconductivity) as quantized persistent currents, critical velocity and Josephson effects. Nevertheless, despite multiple theoretical predictions, hysteresis has not been previously observed in any superfluid, atomic-gas Bose-Einstein condensate. Here we directly detect hysteresis between quantized circulation states in an atomtronic circuit formed from a ring of superfluid Bose-Einstein condensate obstructed by a rotating weak link (a region of low atomic density). This contrasts with previous experiments on superfluid liquid helium where hysteresis was observed directly in systems in which the quantization of flow could not be observed, and indirectly in systems that showed quantized flow. Our techniques allow us to tune the size of the hysteresis loop and to consider the fundamental excitations that accompany hysteresis. The results suggest that the relevant excitations involved in hysteresis are vortices, and indicate that dissipation has an important role in the dynamics. Controlled hysteresis in atomtronic circuits may prove to be a crucial feature for the development of practical devices, just as it has in electronic circuits such as memories, digital noise filters (for example Schmitt triggers) and magnetometers (for example superconducting quantum interference devices).

  17. Clouds and the Earth's Radiant Energy System (CERES) - An Earth Observing System experiment

    NASA Technical Reports Server (NTRS)

    Wielicki, Bruce A.; Barkstrom, Bruce R.

    1991-01-01

    An overview is presented of the CERES experiment that is designed not only to monitor changes in the earth's radiant energy system and cloud systems but to provide these data with enough accuracy and simultaneity to examine the critical climate/cloud feedback mechanisms which may play a major role in determining future changes in the climate system. CERES will estimate not only the flow of radiation at the top of the atmosphere, but also more complete cloud properties that will permit determination of radiative fluxes within the atmosphere and at the surface. The CERES radiation budget data is also planned for utilization in a wide range of other Earth Observing System interdisciplinary science investigations, including studies of land, biological, ocean and atmospheric processes.

  18. Clouds and the Earth's Radiant Energy System (CERES) - An Earth Observing System experiment

    NASA Technical Reports Server (NTRS)

    Wielicki, Bruce A.; Barkstrom, Bruce R.

    1991-01-01

    An overview is presented of the CERES experiment that is designed not only to monitor changes in the earth's radiant energy system and cloud systems but to provide these data with enough accuracy and simultaneity to examine the critical climate/cloud feedback mechanisms which may play a major role in determining future changes in the climate system. CERES will estimate not only the flow of radiation at the top of the atmosphere, but also more complete cloud properties that will permit determination of radiative fluxes within the atmosphere and at the surface. The CERES radiation budget data is also planned for utilization in a wide range of other Earth Observing System interdisciplinary science investigations, including studies of land, biological, ocean and atmospheric processes.

  19. The Burst and Transient Source Experiment Earth Occultation Technique

    NASA Technical Reports Server (NTRS)

    Harmon, B. A.; Fishman, G. J.; Wilson, C. A.; Paciesas, W. S.; Zhang, S. N.; Finger, M. H.; Koshut, T. M.; McCollough, M. L.; Robinson, C. R.; Rubin, B. C.

    2002-01-01

    An Earth orbiting detector sensitive to gamma-ray photons will see step-like occultation features in its count rate when a gamma-ray point source crosses the Earth's limb. This is due to the change in atmospheric attenuation of the gamma rays along the line of sight. In an uncollimated detector, these occultation features can be used to locate and monitor astrophysical sources provided their signals can be individually separated from the detector background. We show that the Earth occultation technique applied to the Burst and Transient Source Experiment (BATSE) on the Compton Gamma Ray Observatory (CGRO) is a viable and flexible all-sky monitor in the low-energy gamma-ray and hard X-ray energy range (20 keV-1 MeV). The method is an alternative to more sophisticated photon imaging devices for astronomy and can serve well as a cost-effective science capability for monitoring the high energy sky. Here we describe the Earth occultation technique for locating new sources and for measuring source intensity and spectra without the use of complex background models. Examples of transform imaging, step searches, spectra, and light curves are presented. Systematic uncertainties due to source confusion, detector response, and contamination from rapid background fluctuations are discussed and analyzed for their effect on intensity measurements. A sky location-dependent average systematic error is derived as a function of Galactic coordinates. The sensitivity of the technique is derived as a function of incident photon energy and also as a function of angle between the source and the normal to the detector entrance window. Occultations of the Crab Nebula by the Moon are used to calibrate Earth occultation flux measurements independent of possible atmospheric scattering effects.

  20. The Burst and Transient Source Experiment Earth Occultation Technique

    NASA Technical Reports Server (NTRS)

    Harmon, B. A.; Fishman, G. J.; Wilson, C. A.; Paciesas, W. S.; Zhang, S. N.; Finger, M. H.; Koshut, T. M.; McCollough, M. L.; Robinson, C. R.; Rubin, B. C.

    2002-01-01

    An Earth orbiting detector sensitive to gamma-ray photons will see step-like occultation features in its count rate when a gamma-ray point source crosses the Earth's limb. This is due to the change in atmospheric attenuation of the gamma rays along the line of sight. In an uncollimated detector, these occultation features can be used to locate and monitor astrophysical sources provided their signals can be individually separated from the detector background. We show that the Earth occultation technique applied to the Burst and Transient Source Experiment (BATSE) on the Compton Gamma Ray Observatory (CGRO) is a viable and flexible all-sky monitor in the low-energy gamma-ray and hard X-ray energy range (20 keV-1 MeV). The method is an alternative to more sophisticated photon imaging devices for astronomy and can serve well as a cost-effective science capability for monitoring the high energy sky. Here we describe the Earth occultation technique for locating new sources and for measuring source intensity and spectra without the use of complex background models. Examples of transform imaging, step searches, spectra, and light curves are presented. Systematic uncertainties due to source confusion, detector response, and contamination from rapid background fluctuations are discussed and analyzed for their effect on intensity measurements. A sky location-dependent average systematic error is derived as a function of Galactic coordinates. The sensitivity of the technique is derived as a function of incident photon energy and also as a function of angle between the source and the normal to the detector entrance window. Occultations of the Crab Nebula by the Moon are used to calibrate Earth occultation flux measurements independent of possible atmospheric scattering effects.

  1. The Nimbus Earth Radiation Budget (ERB) Experiment: 1975 to 1992

    SciTech Connect

    Kyle, H.L.; Arking, A. ); Hickey, J.R. ); Ardanuy, P.E. ); Jacobowitz, H.; Stowe, L.L. ); Campbell, G.G.; Vonder Haar, T. ); House, F.B. ); Maschhoff, R. ); Smith, G.L. )

    1993-05-01

    Three spectrally broadband measurement sets are presently being used for earth radiation budget (ERB) studies: the Nimbus-6 ERB (July 1975 to June 1978), Nimbus-7 ERB (November 1978 to the present), and Earth Radiation Budget Experiment (ERBE) (November 1984 to present). The measurements yield the incident solar irradiance, absorbed solar energy, outgoing longwave and net radiation. The Nimbus-7 started an accurate record of the solar constant in November 1978, while a nearly continuous record of the earth's radiation budget began in July 1975 with the Nimbus-6. Both the Nimbus-6 and -7 products have been reprocessed with improved processing and calibration algorithms so that the entire dataset can be considered as new. However, because of the use of different calibration and processing procedures, the three datasets for some purposes must be considered as piecewise continuous. The Nimbus-7 solar measurements indicate that the sun is a low-level variable star and that the mean annual solar energy just outside the earth's atmosphere was about 0.1% lower in 1984 than in 1979 and 1991. The 9 years of Nimbus-7 ERB measurements show the earth's mean annual energy budget to be stable at the 0.2% level with apparently real changes in the annual emitted longwave at the 0.1% to 0.2% level that are associated with changes in the surface temperature. Other studies deal with the cooling and warming effects of clouds, interregional energy transport, and interannual variations. Current understanding of the sensors and how to derive an accurate mean radiation budget from the measurements has slowly improved. To date, there has been no consensus on the use of consistent calibration and processing procedures to permit quantitatively consistent analyses across the Nimbus-6, -7, and ERBE products. This report describes some successes and lessons learned during the Nimbus ERB program and the compatibility of the Nimbus and ERBE products. 99 refs., 5 figs., 4 tabs.

  2. Hysteresis in Metal Hydrides.

    ERIC Educational Resources Information Center

    Flanagan, Ted B., And Others

    1987-01-01

    This paper describes a reproducible process where the irreversibility can be readily evaluated and provides a thermodynamic description of the important phenomenon of hysteresis. A metal hydride is used because hysteresis is observed during the formation and decomposition of the hydride phase. (RH)

  3. Hysteresis in Metal Hydrides.

    ERIC Educational Resources Information Center

    Flanagan, Ted B., And Others

    1987-01-01

    This paper describes a reproducible process where the irreversibility can be readily evaluated and provides a thermodynamic description of the important phenomenon of hysteresis. A metal hydride is used because hysteresis is observed during the formation and decomposition of the hydride phase. (RH)

  4. NOAA-9 Earth Radiation Budget Experiment (ERBE) scanner offsets determination

    NASA Technical Reports Server (NTRS)

    Avis, Lee M.; Paden, Jack; Lee, Robert B., III; Pandey, Dhirendra K.; Stassi, Joseph C.; Wilson, Robert S.; Tolson, Carol J.; Bolden, William C.

    1994-01-01

    The Earth Radiation Budget Experiment (ERBE) instruments are designed to measure the components of the radiative exchange between the Sun, Earth and space. ERBE is comprised of three spacecraft, each carrying a nearly identical set of radiometers: a three-channel narrow-field-of-view scanner, a two-channel wide-field-of-view (limb-to-limb) non-scanning radiometer, a two-channel medium field-of view (1000 km) non-scanning radiometer, and a solar monitor. Ground testing showed the scanners to be susceptible to self-generated and externally generated electromagnetic noise. This paper describes the pre-launch corrective measures taken and the post-launch corrections to the NOAA-9 scanner data. The NOAA-9 scanner has met the mission objectives in accuracy and precision, in part because of the pre-launch reductions of and post-launch data corrections for the electromagnetic noise.

  5. Characteristics of the earth radiation budget experiment solar monitors

    NASA Technical Reports Server (NTRS)

    Lee, Robert B., III; Barkstrom, Bruce R.; Cess, Robert D.

    1987-01-01

    The earth radiation budget experiment solar monitors, active cavity pyrheliometers, have been developed to measure every two weeks the total optical solar irradiance from the earth radiation budget satellite (ERBS) and the National Oceanic and Atmospheric Administration NOAA-9 spacecraft platforms. In the unfiltered 0.2-50-micron wavelength broadband region, the monitors were used to obtain 1365 W/sq m as the mean value for the solar irradiance, with measurement precisions and accuracies approaching 0.1 and 0.2 percent, respectively. The design and characteristics of the solar monitors are presented along with the data reduction model. For the October 1984 through July 1985 period, the resulting ERBS and NOAA-9 solar irradiance values are intercompared.

  6. Little Earth Experiment: An instrument to model planetary cores

    NASA Astrophysics Data System (ADS)

    Aujogue, Kélig; Pothérat, Alban; Bates, Ian; Debray, François; Sreenivasan, Binod

    2016-08-01

    In this paper, we present a new experimental facility, Little Earth Experiment, designed to study the hydrodynamics of liquid planetary cores. The main novelty of this apparatus is that a transparent electrically conducting electrolyte is subject to extremely high magnetic fields (up to 10 T) to produce electromagnetic effects comparable to those produced by moderate magnetic fields in planetary cores. This technique makes it possible to visualise for the first time the coupling between the principal forces in a convection-driven dynamo by means of Particle Image Velocimetry (PIV) in a geometry relevant to planets. We first present the technology that enables us to generate these forces and implement PIV in a high magnetic field environment. We then show that the magnetic field drastically changes the structure of convective plumes in a configuration relevant to the tangent cylinder region of the Earth's core.

  7. Characteristics of the earth radiation budget experiment solar monitors.

    PubMed

    Lee Iii, R B; Barkstrom, B R; Cess, R D

    1987-08-01

    The earth radiation budget experiment solar monitors, active cavity pyrheliometers, have been developed to measure every two weeks the total optical solar irradiance from the earth radiation budget satellite (ERBS) and the National Oceanic and Atmospheric Administration NOAA-9 spacecraft platforms. In the unfiltered 0.2-50-microm wavelength broadband region, the monitors were used to obtain 1365 W/m(2) as the mean value for the solar irradiance with measurement precisions and accuracies approaching 0.1 and 0.2%, respectively. The design and characteristics of the solar monitors are presented along with the data reduction model. For the Oct. 1984 through July 1985 period, the resulting ERBS and NOAA-9 solar irradiance values are intercompared.

  8. Norfolk State University Research Experience in Earth System Science

    NASA Technical Reports Server (NTRS)

    Chaudhury, Raj

    2002-01-01

    The truly interdisciplinary nature of Earth System Science lends itself to the creation of research teams comprised of people with different scientific and technical backgrounds. In the annals of Earth System Science (ESS) education, the lack of an academic major in the discipline might be seen as a barrier to the involvement of undergraduates in the overall ESS-enterprise. This issue is further compounded at minority-serving institutions by the rarity of departments dedicated to Atmospheric Science, Oceanography or even the geosciences. At Norfolk State University, a Historically Black College, a six week, NASA-supported, summer undergraduate research program (REESS - Research Experience in Earth System Science) is creating a model that involves students with majors in diverse scientific disciplines in authentic ESS research coupled with a structured education program. The project is part of a wider effort at the University to enhance undergraduate education by identifying specific areas of student weaknesses regarding the content and process of science. A pre- and post-assessment test, which is focused on some fundamental topics in global climate change, is given to all participants as part of the evaluation of the program. Student attitudes towards the subject and the program's approach are also surveyed at the end of the research experience. In 2002, 11 undergraduates participated in REESS and were educated in the informed use of some of the vast remote sensing resources available through NASA's Earth Science Enterprise (ESE). The program ran from June 3rd through July 12, 2002. This was the final year of the project.

  9. Dual-domain mass-transfer parameters from electrical hysteresis: theory and analytical approach applied to laboratory, synthetic streambed, and groundwater experiments

    USGS Publications Warehouse

    Briggs, Martin; Day-Lewis, Frederick D.; Ong, John B.; Harvey, Judson W.; Lane, Jr., John W.

    2014-01-01

    Models of dual-domain mass transfer (DDMT) are used to explain anomalous aquifer transport behavior such as the slow release of contamination and solute tracer tailing. Traditional tracer experiments to characterize DDMT are performed at the flow path scale (meters), which inherently incorporates heterogeneous exchange processes; hence, estimated “effective” parameters are sensitive to experimental design (i.e., duration and injection velocity). Recently, electrical geophysical methods have been used to aid in the inference of DDMT parameters because, unlike traditional fluid sampling, electrical methods can directly sense less-mobile solute dynamics and can target specific points along subsurface flow paths. Here we propose an analytical framework for graphical parameter inference based on a simple petrophysical model explaining the hysteretic relation between measurements of bulk and fluid conductivity arising in the presence of DDMT at the local scale. Analysis is graphical and involves visual inspection of hysteresis patterns to (1) determine the size of paired mobile and less-mobile porosities and (2) identify the exchange rate coefficient through simple curve fitting. We demonstrate the approach using laboratory column experimental data, synthetic streambed experimental data, and field tracer-test data. Results from the analytical approach compare favorably with results from calibration of numerical models and also independent measurements of mobile and less-mobile porosity. We show that localized electrical hysteresis patterns resulting from diffusive exchange are independent of injection velocity, indicating that repeatable parameters can be extracted under varied experimental designs, and these parameters represent the true intrinsic properties of specific volumes of porous media of aquifers and hyporheic zones.

  10. Delivery of extraterrestrial amino acids to the primitive Earth. Exposure experiments in Earth orbit.

    PubMed

    Barbier, B; Bertrand, M; Boillot, F; Chabin, A; Chaput, D; Henin, O; Brack, A

    1998-06-01

    A large collection of micrometeorites has been recently extracted from Antarctic old blue ice. In the 50 to 100 micrometers size range, the carbonaceous micrometeorites represent 80% of the samples and contain 2% of carbon. They might have brought more carbon to the surface of the primitive Earth than that involved in the present surficial biomass. Amino acids such as "-amino isobutyric acid have been identified in these Antarctic micrometeorites. Enantiomeric excesses of L-amino acids have been detected in the Murchison meteorite. A large fraction of homochiral amino acids might have been delivered to the primitive Earth via meteorites and micrometeorites. Space technology in Earth orbit offers a unique opportunity to study the behaviour of amino acids required for the development of primitive life when they are exposed to space conditions, either free or associated with tiny mineral grains mimicking the micrometeorites. Our objectives are to demonstrate that porous mineral material protects amino acids in space from photolysis and racemization (the conversion of L-amino acids into a mixture of L- and D-molecules) and to test whether photosensitive amino acids derivatives can polymerize in mineral grains under space conditions. The results obtained in BIOPAN-1 and BIOPAN-2 exposure experiments on board unmanned satellite FOTON are presented.

  11. Flagstaff, Arizona seen in Earth Resources Experiments package

    NASA Image and Video Library

    1974-02-01

    SL4-93-067 (16 Nov. 1973-8 Feb. 1974) --- A spectacular winter view of the Flagstaff, Arizona area is seen in this Skylab 4 Earth Resources Experiments package S190-B (five-inch earth terrain camera) infrared photograph taken from the Skylab space station in Earth orbit. Included in the scene are the San Francisco Mountains, Oak Creek Canyon, Painted Desert and Meteor Crater. The infrared picture depicts in red living vegetation, in white the snow, and in bright blue the water. Major features identified in this photograph are Humphrey's peak, top center, Flagstaff at foot of the peak, Sunset Crater volcanic field with numerous vents and craters right of Flagstaff and Meteor Crater (right center). Within the mountainous areas several clear areas generally rectangular are visible and represent the areas where lumbering has removed the forest. The thin white line extending from left corner to Sunset Crater fields is the power transmission line cleared area. Roads are subdued and are not easily visible. Photo credit: NASA

  12. Characterization of the Earth Radiation Budget Experiment radiometers

    NASA Technical Reports Server (NTRS)

    Lee, R. B., III; Barkstrom, B. R.

    1991-01-01

    The Earth Radiation Budget Experiment (ERBE) scanning radiometers were used to measure the earth's radiation fields during the period November 1984 through February 1990. The ERBE radiometric packages were placed into orbit aboard the Earth Radiation Budget Satellite (ERBS) and the NOAA-9 and NOAA-10 spacecraft platforms. In each radiometric package, thermistor bolometers were used as detection elements for the broadband total (0,2 - 50,0 microns), shortwave (0,2 - 5,0 microns), and longwave (5,0 - 50,0 microns) spectral regions. Flight calibration facilities were built into each of the spacecraft radiometric packages. The flight facilities consisted of black bodies, tungsten lamps, and silicon photodiodes. The black bodies and tungsten lamps were found to be reliable at precision levels approaching 0,5 percent over a five-year period. The photodiodes were found to degrade more than 2 percent during the first year in orbit. In this paper, the flight calibration systems for the ERBE scanning radiometers are described along with the resultant measurements.

  13. Characterization of the Earth Radiation Budget Experiment radiometers

    NASA Technical Reports Server (NTRS)

    Lee, R. B., III; Barkstrom, B. R.

    1991-01-01

    The Earth Radiation Budget Experiment (ERBE) scanning radiometers were used to measure the earth's radiation fields during the period November 1984 through February 1990. The ERBE radiometric packages were placed into orbit aboard the Earth Radiation Budget Satellite (ERBS) and the NOAA-9 and NOAA-10 spacecraft platforms. In each radiometric package, thermistor bolometers were used as detection elements for the broadband total (0,2 - 50,0 microns), shortwave (0,2 - 5,0 microns), and longwave (5,0 - 50,0 microns) spectral regions. Flight calibration facilities were built into each of the spacecraft radiometric packages. The flight facilities consisted of black bodies, tungsten lamps, and silicon photodiodes. The black bodies and tungsten lamps were found to be reliable at precision levels approaching 0,5 percent over a five-year period. The photodiodes were found to degrade more than 2 percent during the first year in orbit. In this paper, the flight calibration systems for the ERBE scanning radiometers are described along with the resultant measurements.

  14. The Burst and Transient Source Experiment (BATSE) Earth Occultation Catalog

    NASA Technical Reports Server (NTRS)

    Wilson-Hodge, Colleen A.

    2004-01-01

    The hard X-ray sky was continuously monitored with the BATSE experiment on the Compton Gamma Ray observatory using the Earth Occultation method. Known sources were monitored twice every orbit and transients could be detected at about the approx. 50 mCrab level on a daily basis. I will summarize the results from our catalog of 179 monitored sources, highlighting observations of black holes and energy spectra for the 83 firmly detected sources and FITS files for all 179 sources. This web database can serve as a guide and comparison tool for future observations with EXIST.

  15. The Burst and Transient Source Experiment (BATSE) Earth Occultation Catalog

    NASA Technical Reports Server (NTRS)

    Wilson-Hodge, Colleen A.

    2004-01-01

    The hard X-ray sky was continuously monitored with the BATSE experiment on the Compton Gamma Ray observatory using the Earth Occultation method. Known sources were monitored twice every orbit and transients could be detected at about the approx. 50 mCrab level on a daily basis. I will summarize the results from our catalog of 179 monitored sources, highlighting observations of black holes and energy spectra for the 83 firmly detected sources and FITS files for all 179 sources. This web database can serve as a guide and comparison tool for future observations with EXIST.

  16. Results of the Compensated Earth-Moon-Earth Retroreflector Laser Link (CEMERLL) Experiment

    NASA Astrophysics Data System (ADS)

    Wilson, K. E.; Leatherman, P. R.; Cleis, R.; Spinhirne, J.; Fugate, R. Q.

    1997-07-01

    Adaptive optics techniques can be used to realize a robust low bit-error-rate link by mitigating the atmosphere-induced signal fades in optical communications links between ground-based transmitters and deep-space probes. Phase I of the Compensated Earth-Moon-Earth Retroreflector Laser Link (CEMERLL) experiment demonstrated the first propagation of an atmosphere-compensated laser beam to the lunar retroreflectors. A 1.06-μ_m Nd:YAG laser beam was propagated through the full aperture of the 1.5-m telescope at the Starfire Optical Range (SOR), Kirtland Air Force Base, New Mexico, to the Apollo 15 retroreflector array at Hadley Rille. Laser guide-star adaptive optics were used to compensate turbulence-induced aberrations across the transmitter's 1.5-m aperture. A 3.5-m telescope, also located at the SOR, was used as a receiver for detecting the return signals. JPL-supplied Chebyshev polynomials of the retroreflector locations were used to develop tracking algorithms for the telescopes. At times we observed in excess of 100 photons returned from a single pulse when the outgoing beam from the 1.5-m telescope was corrected by the adaptive optics system. No returns were detected when the outgoing beam was uncompensated. The experiment was conducted from March through September 1994, during the first or last quarter of the Moon.

  17. Results of the Compensated Earth-Moon-Earth Retroreflector Laser Link (CEMERLL) Experiment

    NASA Technical Reports Server (NTRS)

    Wilson, K. E.; Leatherman, P. R.; Cleis, R.; Spinhirne, J.; Fugate, R. Q.

    1997-01-01

    Adaptive optics techniques can be used to realize a robust low bit-error-rate link by mitigating the atmosphere-induced signal fades in optical communications links between ground-based transmitters and deep-space probes. Phase I of the Compensated Earth-Moon-Earth Retroreflector Laser Link (CEMERLL) experiment demonstrated the first propagation of an atmosphere-compensated laser beam to the lunar retroreflectors. A 1.06-micron Nd:YAG laser beam was propagated through the full aperture of the 1.5-m telescope at the Starfire Optical Range (SOR), Kirtland Air Force Base, New Mexico, to the Apollo 15 retroreflector array at Hadley Rille. Laser guide-star adaptive optics were used to compensate turbulence-induced aberrations across the transmitter's 1.5-m aperture. A 3.5-m telescope, also located at the SOR, was used as a receiver for detecting the return signals. JPL-supplied Chebyshev polynomials of the retroreflector locations were used to develop tracking algorithms for the telescopes. At times we observed in excess of 100 photons returned from a single pulse when the outgoing beam from the 1.5-m telescope was corrected by the adaptive optics system. No returns were detected when the outgoing beam was uncompensated. The experiment was conducted from March through September 1994, during the first or last quarter of the Moon.

  18. Spatial versus time hysteresis in damping mechanisms

    NASA Technical Reports Server (NTRS)

    Banks, H. T.; Fabiano, R. H.; Wang, Y.; Inman, D. J.; Cudney, H., Jr.

    1988-01-01

    A description is given of continuing investigations on the task of estimating internal damping mechanisms in flexible structures. Specifically, two models for internal damping in Euler-Bernoulli beams are considered: spatial hysteresis and time hysteresis. A theoretically sound computational algorithm for estimation is described, and experimental results are discussed. It is concluded that both models perform well in the sense that they accurately predict response for the experiments conducted.

  19. Intracellular molecular distributions in spacecraft experiments in orbit around Earth

    NASA Astrophysics Data System (ADS)

    Haranas, Ioannis; Gkigkitzis, Ioannis; Zouganelis, George D.

    2012-04-01

    It is possible that the nucleolous inside the cell plays the role of a "gravity receptor". Furthermore, cells up to 10 μm in diameter can demonstrate some effect due to the redistribution of mitochondria or nucleolous. Effects of gravity should be present in various cell systems where larger objects such as the ribosomes move from cell to cell. In this paper we study the effects of gravity on cells. In particular, we examine the resulting intracellular molecular distribution due to Brownian motion and the ordered distribution of molecules under the action of gravity, where n0 is the number per unit volume at certain level, and n is the number per unit volume above that level. This is an experiment that takes place at a certain orbital altitude in a spacecraft in orbit around Earth, where the acceleration due to the central field is corrected for the oblateness and also the rotation of the Earth. We found that equatorial circular and elliptical orbits have the highest n/n0 ratios. This experiment takes place in circular and elliptical orbits, with eccentricities e = 0, 0.1 and involves a bacterial cell at an orbital altitude of 300 km. We found that n/n0 = 1.00299 and 1.0037 respectively, which is still a 0.6-0.7 % higher than n/n0 = 0.0996685 calculated on the surface of the Earth. Examining mitochondria in similar orbital experiments we found that equatorial orbits result to higher n/n0 ratios. In particular, we found that n/n0 = 8.38119, where an elliptical orbit of eccentricity e = 0.1 results to n/n0 = 13.8525. Both are high above 100%, signifying the importance of Brownian motion over gravity. Our results are of interest to biomedical applications. Molecular concentrations are important for various processes such as the embryogenesis, positional homeostasis and its relation to cell energy expenditure, cell torque, cell deformation, and more. These results indicate that statistical molecular distributions play an important role for the recognition of a

  20. Hysteresis and Fatigue

    NASA Astrophysics Data System (ADS)

    Erber, T.; Guralnick, S. A.; Michels, S. C.

    1993-06-01

    Fatigue in materials is the result of cumulative damage processes that are usually induced be repeated loading cycles. Since the energy dissipation associated with damage is irreversible, and the loading cycles are accompanied by the evolution of heat, the corresponding relation between stress and strain is not single-valued; but rather exhibits a memory dependence, or hysteresis. Conversely, sustained hysteresis is a necessary condition for fatigue and is related to the rate of damage accumulation. Engineering design and safety standards for estimating fatigue life are based in part on the Manson-Coffin relations between the width of stress-strain hysteresis loops and the number of loading cycles required to produce failure in test pieces. Experimental and theoretical results show that this relation can be extended into a simple phenomenological description of fatigue that directly links total hysteresis energy dissipation, the cumulation of material damage, and the average number of loading cycles leading to failure. Detailed features of the hysteresis can be understood with the help of analogies between the incremental collapse of structures and the inception and organization of damage in materials. In particular, scanning tunneling microscope measurements of the threshold of mechanical irreversibility and acoustic emission patterns may be used to check on the evolution of hysteresis at the microscopic level.

  1. Hysteresis and fatigue

    SciTech Connect

    Erber, T. ); Guralnick, S.A.; Michels, S.C. )

    1993-06-01

    Energy dissipation associated with damage of materials is irreversible and loading cycles are accompanied by the evolution of heat. The relation between energy dissipation and loading therefore exhibits a memory dependence or hysteresis. Conversely, sustained hysteresis is a necessary condition for fatigue and is related to the rate of damage accumulation. Standards for estimating fatigue life are partially based on the Manson-Coffin relations between the width of stress strain hysteresis loops and the number of loading cycles required to produce failure in test pieces. In the present study, experimental and theoretical results demonstrate that this relation can be extended into a simple phenomenological description of fatigue that directly links total hysteresis energy dissipation, the cumulation of material damage, and the average number of loading cycles leading to failure. Analogies between the incremental collapse of structures and the inception and organization of damage in materials are used to aid understanding of the detailed features of hysteresis. Scanning tunneling microscope measurements of the threshold of mechanical irreversibility and acoustic emission patterns are used to detect the evolution of hysteresis at the microscopic level. 61 refs., 14 figs., 1 tab.

  2. Fatigue, Hysteresis and Acoustic Emission. Parts 1 and 2

    DTIC Science & Technology

    1992-05-15

    Strain Controlled Fatigue Experiment in Progress ............ 47 25. Typical Hysteresis Loop Displayed with Data Points ..................... 48 26...88 52. Typical Hysteresis Loops from a Staircase Load Program ................. 89 53. Typical Strain Controlled Fatigue Experiment Displaying Strain ...area is difficult, if not impossible. Hence, the shift from stress controlled to strain controlled experiments. During this period, separating the total

  3. Experiences & Tools from Modeling Instruction Applied to Earth Sciences

    NASA Astrophysics Data System (ADS)

    Cervenec, J.; Landis, C. E.

    2012-12-01

    The Framework for K-12 Science Education calls for stronger curricular connections within the sciences, greater depth in understanding, and tasks higher on Bloom's Taxonomy. Understanding atmospheric sciences draws on core knowledge traditionally taught in physics, chemistry, and in some cases, biology. If this core knowledge is not conceptually sound, well retained, and transferable to new settings, understanding the causes and consequences of climate changes become a task in memorizing seemingly disparate facts to a student. Fortunately, experiences and conceptual tools have been developed and refined in the nationwide network of Physics Modeling and Chemistry Modeling teachers to build necessary understanding of conservation of mass, conservation of energy, particulate nature of matter, kinetic molecular theory, and particle model of light. Context-rich experiences are first introduced for students to construct an understanding of these principles and then conceptual tools are deployed for students to resolve misconceptions and deepen their understanding. Using these experiences and conceptual tools takes an investment of instructional time, teacher training, and in some cases, re-envisioning the format of a science classroom. There are few financial barriers to implementation and students gain a greater understanding of the nature of science by going through successive cycles of investigation and refinement of their thinking. This presentation shows how these experiences and tools could be used in an Earth Science course to support students developing conceptually rich understanding of the atmosphere and connections happening within.

  4. High temperature heat pipe experiments in low earth orbit

    SciTech Connect

    Woloshun, K.; Merrigan, M.A.; Sena, J.T. ); Critchley, E. )

    1993-01-01

    Although high temperature, liquid metal heat pipe radiators have become a standard component on most high power space power system designs, there is no experimental data on the operation of these heat pipes in a zero gravity or micro-gravity environment. Experiments to benchmark the transient and steady state performance of prototypical heat pipe space radiator elements are in preparation for testing in low earth orbit. It is anticipated that these heat pipes will be tested aborad the Space Shuttle in 1995. Three heat pipes will be tested in a cargo bay Get Away Special (GAS) canister. The heat pipes are SST/potassium, each with a different wick structure; homogeneous, arterial, and annular gap, the heat pipes have been designed, fabricated, and ground tested. In this paper, the heat pipe designs are specified, and transient and steady-state ground test data are presented.

  5. High temperature heat pipe experiments in low earth orbit

    SciTech Connect

    Woloshun, K.; Merrigan, M.A.; Sena, J.T.; Critchley, E.

    1993-02-01

    Although high temperature, liquid metal heat pipe radiators have become a standard component on most high power space power system designs, there is no experimental data on the operation of these heat pipes in a zero gravity or micro-gravity environment. Experiments to benchmark the transient and steady state performance of prototypical heat pipe space radiator elements are in preparation for testing in low earth orbit. It is anticipated that these heat pipes will be tested aborad the Space Shuttle in 1995. Three heat pipes will be tested in a cargo bay Get Away Special (GAS) canister. The heat pipes are SST/potassium, each with a different wick structure; homogeneous, arterial, and annular gap, the heat pipes have been designed, fabricated, and ground tested. In this paper, the heat pipe designs are specified, and transient and steady-state ground test data are presented.

  6. Wetting hysteresis induced by nanodefects

    PubMed Central

    Giacomello, Alberto; Schimmele, Lothar; Dietrich, Siegfried

    2016-01-01

    Wetting of actual surfaces involves diverse hysteretic phenomena stemming from ever-present imperfections. Here, we clarify the origin of wetting hysteresis for a liquid front advancing or receding across an isolated defect of nanometric size. Various kinds of chemical and topographical nanodefects, which represent salient features of actual heterogeneous surfaces, are investigated. The most probable wetting path across surface heterogeneities is identified by combining, within an innovative approach, microscopic classical density functional theory and the string method devised for the study of rare events. The computed rugged free-energy landscape demonstrates that hysteresis emerges as a consequence of metastable pinning of the liquid front at the defects; the barriers for thermally activated defect crossing, the pinning force, and hysteresis are quantified and related to the geometry and chemistry of the defects allowing for the occurrence of nanoscopic effects. The main result of our calculations is that even weak nanoscale defects, which are difficult to characterize in generic microfluidic experiments, can be the source of a plethora of hysteretical phenomena, including the pinning of nanobubbles. PMID:26721395

  7. Wetting hysteresis induced by nanodefects.

    PubMed

    Giacomello, Alberto; Schimmele, Lothar; Dietrich, Siegfried

    2016-01-19

    Wetting of actual surfaces involves diverse hysteretic phenomena stemming from ever-present imperfections. Here, we clarify the origin of wetting hysteresis for a liquid front advancing or receding across an isolated defect of nanometric size. Various kinds of chemical and topographical nanodefects, which represent salient features of actual heterogeneous surfaces, are investigated. The most probable wetting path across surface heterogeneities is identified by combining, within an innovative approach, microscopic classical density functional theory and the string method devised for the study of rare events. The computed rugged free-energy landscape demonstrates that hysteresis emerges as a consequence of metastable pinning of the liquid front at the defects; the barriers for thermally activated defect crossing, the pinning force, and hysteresis are quantified and related to the geometry and chemistry of the defects allowing for the occurrence of nanoscopic effects. The main result of our calculations is that even weak nanoscale defects, which are difficult to characterize in generic microfluidic experiments, can be the source of a plethora of hysteretical phenomena, including the pinning of nanobubbles.

  8. Adsorption hysteresis in nanopores

    PubMed

    Neimark; Ravikovitch; Vishnyakov

    2000-08-01

    Capillary condensation hysteresis in nanopores is studied by Monte Carlo simulations and the nonlocal density functional theory. Comparing the theoretical results with the experimental data on low temperature sorption of nitrogen and argon in cylindrical channels of mesoporous siliceous molecular sieves of MCM-41 type, we have revealed four qualitatively different sorption regimes depending on the temperature and pore size. As the pore size increases at a given temperature, or as the temperature decreases at a given pore size, the following regimes are consequently observed: volume filling without phase separation, reversible stepwise capillary condensation, irreversible capillary condensation with developing hysteresis, and capillary condensation with developed hysteresis. We show that, in the regime of developed hysteresis (pores wider than 5 nm in the case of nitrogen sorption at 77 K), condensation occurs spontaneously at the vaporlike spinodal while desorption takes place at the equilibrium. A quantitative agreement is found between the modeling results and the experimental hysteresis loops formed by the adsorption-desorption isotherms. The results obtained provide a better understanding of the general behavior of confined fluids and the specifics of sorption and phase transitions in nanomaterials.

  9. Load-Dependent Friction Hysteresis on Graphene.

    PubMed

    Ye, Zhijiang; Egberts, Philip; Han, Gang Hee; Johnson, A T Charlie; Carpick, Robert W; Martini, Ashlie

    2016-05-24

    Nanoscale friction often exhibits hysteresis when load is increased (loading) and then decreased (unloading) and is manifested as larger friction measured during unloading compared to loading for a given load. In this work, the origins of load-dependent friction hysteresis were explored through atomic force microscopy (AFM) experiments of a silicon tip sliding on chemical vapor deposited graphene in air, and molecular dynamics simulations of a model AFM tip on graphene, mimicking both vacuum and humid air environmental conditions. It was found that only simulations with water at the tip-graphene contact reproduced the experimentally observed hysteresis. The mechanisms underlying this friction hysteresis were then investigated in the simulations by varying the graphene-water interaction strength. The size of the water-graphene interface exhibited hysteresis trends consistent with the friction, while measures of other previously proposed mechanisms, such as out-of-plane deformation of the graphene film and irreversible reorganization of the water molecules at the shearing interface, were less correlated to the friction hysteresis. The relationship between the size of the sliding interface and friction observed in the simulations was explained in terms of the varying contact angles in front of and behind the sliding tip, which were larger during loading than unloading.

  10. The Earth Radiation Budget (ERB) experiment - An overview

    NASA Technical Reports Server (NTRS)

    Jacobowitz, H.; Soule, H. V.; Kyle, H. L.; House, F. B.

    1984-01-01

    The development of ERB observational systems is traced from its beginnings in the late 1950's through to the current ERB on the Nimbus 7 satellite. The instruments comprising the current 22-channel ERB experiment are described in some detail. Noteworthy are the inclusion in one solar channel, of a self-calibrating cavity to measure the solar constant and the use of biaxial scanning telescopes to determine the angular reflection and emission model required for processing the narrow-angle radiometric data. A fairly detailed description of the prelaunch and in-flight calibrations is given along with an analysis of the radiometric performance of the instruments. The data processing system is traced with the aid of a schematic flow diagram showing the steps required to produce the many tape and microfilm products archived. Future plans for improving the quality and accuracy of the data products are discussed. Finally, the upcoming Earth Radiation Budget Experiment (ERBE) is briefly mentioned. It will be capable of simultaneously measuring the radiation budget from three satellites, each having a different equator crossing time and angle.

  11. The Earth Radiation Budget (ERB) experiment - An overview

    NASA Technical Reports Server (NTRS)

    Jacobowitz, H.; Soule, H. V.; Kyle, H. L.; House, F. B.

    1984-01-01

    The development of ERB observational systems is traced from its beginnings in the late 1950's through to the current ERB on the Nimbus 7 satellite. The instruments comprising the current 22-channel ERB experiment are described in some detail. Noteworthy are the inclusion in one solar channel, of a self-calibrating cavity to measure the solar constant and the use of biaxial scanning telescopes to determine the angular reflection and emission model required for processing the narrow-angle radiometric data. A fairly detailed description of the prelaunch and in-flight calibrations is given along with an analysis of the radiometric performance of the instruments. The data processing system is traced with the aid of a schematic flow diagram showing the steps required to produce the many tape and microfilm products archived. Future plans for improving the quality and accuracy of the data products are discussed. Finally, the upcoming Earth Radiation Budget Experiment (ERBE) is briefly mentioned. It will be capable of simultaneously measuring the radiation budget from three satellites, each having a different equator crossing time and angle.

  12. The earth radiation budget experiment: Early validation results

    NASA Astrophysics Data System (ADS)

    Smith, G. Louis; Barkstrom, Bruce R.; Harrison, Edwin F.

    The Earth Radiation Budget Experiment (ERBE) consists of radiometers on a dedicated spacecraft in a 57° inclination orbit, which has a precessional period of 2 months, and on two NOAA operational meteorological spacecraft in near polar orbits. The radiometers include scanning narrow field-of-view (FOV) and nadir-looking wide and medium FOV radiometers covering the ranges 0.2 to 5 μm and 5 to 50 μm and a solar monitoring channel. This paper describes the validation procedures and preliminary results. Each of the radiometer channels underwent extensive ground calibration, and the instrument packages include in-flight calibration facilities which, to date, show negligible changes of the instruments in orbit, except for gradual degradation of the suprasil dome of the shortwave wide FOV (about 4% per year). Measurements of the solar constant by the solar monitors, wide FOV, and medium FOV radiometers of two spacecraft agree to a fraction of a percent. Intercomparisons of the wide and medium FOV radiometers with the scanning radiometers show agreement of 1 to 4%. The multiple ERBE satellites are acquiring the first global measurements of regional scale diurnal variations in the Earth's radiation budget. These diurnal variations are verified by comparison with high temporal resolution geostationary satellite data. Other principal investigators of the ERBE Science Team are: R. Cess, SUNY, Stoneybrook; J. Coakley, NCAR; C. Duncan, M. King and A Mecherikunnel, Goddard Space Flight Center, NASA; A. Gruber and A.J. Miller, NOAA; D. Hartmann, U. Washington; F.B. House, Drexel U.; F.O. Huck, Langley Research Center, NASA; G. Hunt, Imperial College, London U.; R. Kandel and A. Berroir, Laboratory of Dynamic Meteorology, Ecole Polytechique; V. Ramanathan, U. Chicago; E. Raschke, U. of Cologne; W.L. Smith, U. of Wisconsin and T.H. Vonder Haar, Colorado State U.

  13. Mission Preparation Program for Exobiological Experiments in Earth Orbit

    NASA Astrophysics Data System (ADS)

    Panitz, Corinna; Reitz, Guenther; Horneck, Gerda; Rabbow, Elke; Rettberg, Petra

    The ESA facilities EXPOSE-R and EXPOSE-E on board of the the International Space Station ISS provide the technology for exposing chemical and biological samples in a controlled manner to outer space parameters, such as high vacuum, intense radiation of galactic and solar origin and microgravity. EXPOSE-E has been attached to the outer balcony of the European Columbus module of the ISS in Febraury 2008 and will stay for about 1 year in space, EXPOSE-R will be attached to the Russian Svezda module of the ISS in fall 2008. The EXPOSE facilities are a further step in the study of the Responses of Organisms to Space Environment (ROSE concortium). The results from the EXPOSE missions will give new insights into the survivability of terrestrial organisms in space and will contribute to the understanding of the organic chemistry processes in space, the biological adaptation strategies to extreme conditions, e.g. on early Earth and Mars, and the distribution of life beyond its planet of origin.To test the compatibility of the different biological and chemical systems and their adaptation to the opportunities and constraints of space conditions a profound ground support program has been developed. It resulted in several experiment verification tests EVTs and an experiment sequence test EST that were conducted in the carefully equipped and monitored planetary and space simulation facilities PSI of the Institute of Aerospace Medicine at DLR in Cologne, Germany. These ground based pre-flight studies allow the investigation of a much wider variety of samples and the selection of the most promising organisms for the flight experiment. The procedure and results of these EVT tests and EST will be presented. These results are an essential prerequisite for the success of the EXPOSE missions and have been done in parallel with the development and construction of the final hardware design of the facility. The results gained during the simulation experiments demonstrated mission

  14. Addressing Earth Science Data Access Challenges through User Experience Research

    NASA Astrophysics Data System (ADS)

    Hemmings, S. N.; Banks, B.; Kendall, J.; Lee, C. M.; Irwin, D.; Toll, D. L.; Searby, N. D.

    2013-12-01

    The NASA Capacity Building Program (Earth Science Division, Applied Sciences Program) works to enhance end-user capabilities to employ Earth observation and Earth science (EO/ES) data in decision-making. Open data access and user-tailored data delivery strategies are critical elements towards this end. User Experience (UX) and User Interface (UI) research methods can offer important contributions towards addressing data access challenges, particularly at the interface of science application/product development and product transition to end-users. This presentation focuses on developing nation contexts and describes methods, results, and lessons learned from two recent UX/UI efforts conducted in collaboration with NASA: the SERVIRglobal.net redesign project and the U.S. Water Partnership (USWP) Portal development effort. SERVIR, a collaborative venture among NASA, USAID, and global partners, seeks to improve environmental management and climate change response by helping governments and other stakeholders integrate EO and geospatial technologies into decision-making. The USWP, a collaboration among U.S. public and private sectors, harnesses U.S.-based resources and expertise to address water challenges in developing nations. SERVIR's study, conducted from 2010-2012, assessed and tested user needs, preferences, and online experiences to generate a more user-friendly online data portal at SERVIRglobal.net. The portal provides a central access interface to data and products from SERVIR's network of hubs in East Africa, the Hindu Kush Himalayas, and Mesoamerica. The second study, conducted by the USWP Secretariat and funded by the U.S. Department of State, seeks to match U.S.-based water information resources with developing nation stakeholder needs. The USWP study utilizes a multi-pronged approach to identify key design requirements and to understand the existing water data portal landscape. Adopting UX methods allows data distributors to design customized UIs that

  15. Science support for the Earth radiation budget experiment

    NASA Technical Reports Server (NTRS)

    Coakley, James A., Jr.

    1994-01-01

    The work undertaken as part of the Earth Radiation Budget Experiment (ERBE) included the following major components: The development and application of a new cloud retrieval scheme to assess errors in the radiative fluxes arising from errors in the ERBE identification of cloud conditions. The comparison of the anisotropy of reflected sunlight and emitted thermal radiation with the anisotropy predicted by the Angular Dependence Models (ADM's) used to obtain the radiative fluxes. Additional studies included the comparison of calculated longwave cloud-free radiances with those observed by the ERBE scanner and the use of ERBE scanner data to track the calibration of the shortwave channels of the Advanced Very High Resolution Radiometer (AVHRR). Major findings included: the misidentification of cloud conditions by the ERBE scene identification algorithm could cause 15 percent errors in the shortwave flux reflected by certain scene types. For regions containing mixtures of scene types, the errors were typically less than 5 percent, and the anisotropies of the shortwave and longwave radiances exhibited a spatial scale dependence which, because of the growth of the scanner field of view from nadir to limb, gave rise to a view zenith angle dependent bias in the radiative fluxes.

  16. Reversible hysteresis loop tuning

    NASA Astrophysics Data System (ADS)

    Berger, A.; Binek, Ch.; Margulies, D. T.; Moser, A.; Fullerton, E. E.

    2006-02-01

    We utilize antiferromagnetically coupled bilayer structures to magnetically tune hysteresis loop properties. Key element of this approach is the non-overlapping switching field distribution of the two magnetic layers that make up the system: a hard magnetic CoPtCrB layer (HL) and a soft magnetic CoCr layer (SL). Both layers are coupled antiferromagnetically through an only 0.6-nm-thick Ru interlayer. The non-overlapping switching field distribution allows the measurement of magnetization reversal in the SL at low fields while keeping the magnetization state of the HL unperturbed. Applying an appropriate high field or high field sequence changes the magnetic state of the HL, which then influences the SL magnetization reversal due to the interlayer coupling. In this way, the position and shape of the SL hysteresis loop can be changed or tuned in a fully reversible and highly effective manner. Here, we study specifically how the SL hysteresis loop characteristics change as we move the HL through an entire high field hysteresis loop sequence.

  17. The Moon and Earth Radiation Budget Experiment (MERBE)

    NASA Astrophysics Data System (ADS)

    Matthews, G.

    2016-12-01

    Recent work by the NASA CLARREO team reports that calibration quality of existing space-based Earth Radiation Budget (ERB) measurements is insufficient to detect important model predicted cloud climate forcing trends in the near future, given the estimated sizes of the signals of interest. Additional statistical results from the same studies show that no mission, even those using improved concepts in development, will provide the data accuracy required to detect such predicted but uncertain climate signals for at least twenty years. Hence a new project called the Moon and Earth Radiation Budget Experiment (MERBE) is underway. Primary to MERBE, multiple orbiting CERES ERB devices have each been precisely and completely re-calibrated. Now they consistently measure a constant SI traceable lunar solar albedo and thermal output as in Fig (a), aligned so a start of century ERB imbalance of +0.85W/m2can be used to asses climate change (see lower Fig (b)). Using the Moon removes instrument biases and the significant artificial calibration drifts found in the existing EBAF product from CERES (upper Fig (b)). The polarities of these false drifts in EBAF are such that they also may explain some of the `missing energy' anomaly. The same CLARREO statistical methods when applied to preliminary MERBE results then suggest it has the capability to immediately begin the narrowing of uncertainty in climate sensitivity, near a quarter of a century sooner than currently thought possible (see Fig (c)). Remaining single scanner footprint (SSF) MERBE files are currently in production by Zedika LLC. Following a free word-wide release after 2016 the imbalance plot of lower Fig (b) can be extended to the present day, with the new assurance that no artificial calibration trends are present (i.e. from Fig (a)). Click below for MERBE white paper submitted to ESAS2017, the 2015 CALCON presentation to the calibration community and a preview animation of MERBE data to be released next year: http

  18. Hysteresis in the Sky

    NASA Astrophysics Data System (ADS)

    Choudhury, Sayantan; Banerjee, Shreya

    2016-07-01

    Hysteresis is a phenomenon occurring naturally in several magnetic and electric materials in condensed matter physics. When applied to cosmology, aka cosmological hysteresis, has interesting and vivid implications in the scenario of a cyclic bouncy universe. Most importantly, this physical prescription can be treated as an alternative proposal to inflationary paradigm. Cosmological hysteresis is caused by the asymmetry in the equation of state parameter during expansion and contraction phase of the universe, due to the presence of a single scalar field. This process is purely thermodynamical in nature, results in a non-vanishing hysteresis loop integral (∮pdV) in cosmology. When applied to variants of modified gravity models 1) Dvali-Gabadadze-Porrati (DGP) brane world gravity, 2) Cosmological constant dominated Einstein gravity, 3) Loop Quantum Gravity (LQG), 4) Einstein-Gauss-Bonnet brane world gravity and 5) Randall Sundrum single brane world gravity (RSII), under certain circumstances, this phenomenon leads to the increase in amplitude of the consecutive cycles and to a universe with older and larger successive cycles, provided we have physical mechanisms to make the universe bounce and turnaround. This inculcates an arrow of time in a dissipationless cosmology. Remarkably, this phenomenon appears to be widespread in several cosmological potentials in variants of modified gravity background, which we explicitly study for i) Hilltop, ii) Natural and iii) Coleman-Weinberg potentials, in this paper. Semi-analytical analysis of these models, for different potentials with minimum/minima, show that the conditions which creates a universe with an ever increasing expansion, depend on the signature of the hysteresis loop integral (∮pdV) as well as on the variants of model parameters.

  19. The Crew Earth Observations Experiment: Earth System Science from the ISS

    NASA Technical Reports Server (NTRS)

    Stefanov, William L.; Evans, Cynthia A.; Robinson, Julie A.; Wilkinson, M. Justin

    2007-01-01

    This viewgraph presentation reviews the use of Astronaut Photography (AP) as taken from the International Space Station (ISS) in Earth System Science (ESS). Included are slides showing basic remote sensing theory, data characteristics of astronaut photography, astronaut training and operations, crew Earth observations group, targeting sites and acquisition, cataloging and database, analysis and applications for ESS, image analysis of particular interest urban areas, megafans, deltas, coral reefs. There are examples of the photographs and the analysis.

  20. Land Use Planning Experiment for Introductory Earth Science Courses

    ERIC Educational Resources Information Center

    Fetter, C. W., Jr.; Hoffman, James I.

    1975-01-01

    Describes an activity which incorporates topographic map interpretation, soils analysis, hydrogeology, and local geology in a five-week series of exercises for an introductory college earth science class. (CP)

  1. Land Use Planning Experiment for Introductory Earth Science Courses

    ERIC Educational Resources Information Center

    Fetter, C. W., Jr.; Hoffman, James I.

    1975-01-01

    Describes an activity which incorporates topographic map interpretation, soils analysis, hydrogeology, and local geology in a five-week series of exercises for an introductory college earth science class. (CP)

  2. Hysteresis in structural dynamics

    NASA Astrophysics Data System (ADS)

    Ivanyi, A.; Ivanyi, P.; Ivanyi, M. M.; Ivanyi, M.

    2012-05-01

    In this paper the Preisach hysteresis model is applied to determine the dynamic behavior of a steel column with mass on the top and loaded by an impulse force. The column is considered as a rigid element, while the fixed end of the column is modeled with a rotational spring of hysterestic characteristic. In the solution of the non-linear dynamical equation of motion the fix-point technique is inserted to the time marching iteration. In the investigation the non-linearity of the rotation spring is modeled with the Preisach hysteresis model. The variation of amplitude and the action time interval of force are changing. The results are plotted in figures.

  3. Patterns in Crew-Initiated Photography of Earth from ISS - Is Earth Observation a Salutogenic Experience?

    NASA Technical Reports Server (NTRS)

    Robinson, Julie A.; Slack, Kelley J.; Olson, Valerie A.; Trenchard, Mike; Willis, Kim; Baskin, Pam; Ritsher, Jennifer Boyd

    2006-01-01

    To provide for the well-being of crewmembers on future exploration missions, understanding how space station crewmembers handle the inherently stressful isolation and confinement during long-duration missions is important. A recent retrospective survey of previously flown astronauts found that the most commonly reported psychologically enriching aspects of spaceflight had to do with their Perceptions of Earth. Crewmembers onboard the International Space Station (ISS) photograph Earth through the station windows. Some of these photographs are in response to requests from scientists on the ground through the Crew Earth Observations (CEO) payload. Other photographs taken by crewmembers have not been in response to these formal requests. The automatically recorded data from the camera provides a dataset that can be used to test hypotheses about factors correlated with self-initiated crewmember photography. The present study used objective in-flight data to corroborate the previous questionnaire finding and to further investigate the nature of voluntary Earth-Observation activity. We examined the distribution of photographs with respect to time, crew, and subject matter. We also determined whether the frequency fluctuated in conjunction with major mission events such as vehicle dockings, and extra-vehicular activities (EVAs, or spacewalks), relative to the norm for the relevant crew. We also examined the influence of geographic and temporal patterns on frequency of Earth photography activities. We tested the hypotheses that there would be peak photography intensity over locations of personal interest, and on weekends. From December 2001 through October 2005 (Expeditions 4-11) crewmembers took 144,180 photographs of Earth with time and date automatically recorded by the camera. Of the time-stamped photographs, 84.5% were crew-initiated, and not in response to CEO requests. Preliminary analysis indicated some phasing in patterns of photography during the course of a

  4. Hysteresis of ionization waves

    SciTech Connect

    Dinklage, A.; Bruhn, B.; Testrich, H.; Wilke, C.

    2008-06-15

    A quasi-logistic, nonlinear model for ionization wave modes is introduced. Modes are due to finite size of the discharge and current feedback. The model consists of competing coupled modes and it incorporates spatial wave amplitude saturation. The hysteresis of wave mode transitions under current variation is reproduced. Sidebands are predicted by the model and found in experimental data. The ad hoc model is equivalent to a general--so-called universal--approach from bifurcation theory.

  5. A magnetic hysteresis model

    NASA Technical Reports Server (NTRS)

    Flatley, Thomas W.; Henretty, Debra A.

    1995-01-01

    The Passive Aerodynamically Stabilized Magnetically Damped Satellite (PAMS) will be deployed from the Space Shuttle and used as a target for a Shuttle-mounted laser. It will be a cylindrical satellite with several corner cube reflectors on the ends. The center of mass of the cylinder will be near one end, and aerodynamic torques will tend to align the axis of the cylinder with the spacecraft velocity vector. Magnetic hysteresis rods will be used to provide passive despin and oscillation-damping torques on the cylinder. The behavior of the hysteresis rods depends critically on the 'B/H' curves for the combination of materials and rod length-to-diameter ratio ('l-over-d'). These curves are qualitatively described in most Physics textbooks in terms of major and minor 'hysteresis loops'. Mathematical modeling of the functional relationship between B and H is very difficult. In this paper, the physics involved is not addressed, but an algorithm is developed which provides a close approximation to empirically determined data with a few simple equations suitable for use in computer simulations.

  6. Earth viewing with a shuttleborne experiment pointing mount

    NASA Technical Reports Server (NTRS)

    Iwens, R. P.; Mayo, R. A.; Spector, V. A.; Van Vooren, R. H.

    1978-01-01

    The article considers the attitude determination and the control problems of the shuttleborne earth-viewing pointing mounts (EPMs). Per-axis pointing performance requirements are identified for troposphere/stratosphere pollution, tropical storm research, and urban air pollution. Ephemeris error contributions to earth pointing are discussed and candidate attitude reference systems are described. Primary interfaces between the orbiter flight control system, Spacelab, pallet-mounted EPM, and control subsystems are outlined. A block diagram is given of the EPM-mounted stellar-inertial attitude reference system. The system's performance is evaluated on the basis of the inertial sensor and a three-axis covariance analysis.

  7. Earth viewing with a shuttleborne experiment pointing mount

    NASA Technical Reports Server (NTRS)

    Iwens, R. P.; Mayo, R. A.; Spector, V. A.; Van Vooren, R. H.

    1978-01-01

    The article considers the attitude determination and the control problems of the shuttleborne earth-viewing pointing mounts (EPMs). Per-axis pointing performance requirements are identified for troposphere/stratosphere pollution, tropical storm research, and urban air pollution. Ephemeris error contributions to earth pointing are discussed and candidate attitude reference systems are described. Primary interfaces between the orbiter flight control system, Spacelab, pallet-mounted EPM, and control subsystems are outlined. A block diagram is given of the EPM-mounted stellar-inertial attitude reference system. The system's performance is evaluated on the basis of the inertial sensor and a three-axis covariance analysis.

  8. Earth observations and photography experiment: Summary of significant results

    NASA Technical Reports Server (NTRS)

    El-Baz, F.

    1978-01-01

    Observation and photographic data from the Apollo Soyuz Test Project are analyzed. The discussion is structured according to the fields of investigation including: geology, desert studies, oceanography, hydrology, and meteorology. The data were obtained by: (1) visual observations of selected Earth features, (2) hand-held camera photography to document observations, and (3) stereo mapping photography of areas of significant scientific interest.

  9. Mission requirements for a manned earth observatory. Volume 1, task 1: Experiment selection, definition, and documentation

    NASA Technical Reports Server (NTRS)

    1973-01-01

    Information related to proposed earth observation experiments for shuttle sortie missions (SSM) in the 1980's is presented. The step-wise progression of study activities and the development of the rationale that led to the identification, selection, and description of earth observation experiments for SSM are listed. The selected experiments are described, defined, and documented by individual disciplines. These disciplines include: oceanography; meteorology; agriculture, forestry, and rangeland; geology; hydrology; and environmental impact.

  10. Bringing Ad-Hoc Analytics to Big Earth Data: the EarthServer Experience

    NASA Astrophysics Data System (ADS)

    Baumann, Peter

    2014-05-01

    From the commonly accepted Vs defining the Big Data challenge - volume, velocity, variety - we more and more learn that the sheer volume is not the only, and often not even the decisive factor inhibiting access and analytics. In particular variety of data is a frequent core issue, posing manifold issues. Based on this observation we claim that a key aspect to analytics is the freedom to ask any questions, simple or complex, anytime and combining any choice of data structures, whatever diverging they may be. Actually, techniques for such "ad-hoc queries" we can learn from classical databases. Their concept of high-level query languages brings along several benefits: a uniform semantic, allowing machine-to-machine communication, including automatic generation of queries; massive server-side optimization and parallelization; and building attractive client interfaces hiding the query syntax from casual users while allowing power users to utilize it. However, these benefits used to be available only on tabular and set oriented data, text, and - more recently - graph data. With the advent of Array Databases, they become available on large multidimensional raster data assets as well, getting one step closer to the Holy Grail of itnegrated, uniform retrieval for users. ErthServer is a transatlantic initiative setting up operationa linfrastructures based on this paradigm. In our talk, we present core EarthServer technology concepts as well as a spectrum of Earth Science applications utilizing the EarthServer platform for versatile, visualisation supported analytics services. Further, we discuss the substantial impact EarthServer is having on Big Geo Data standardization in OGC and ISO. Time and Internet connection permitting a live demo can be presented.

  11. Role of hysteresis in stomatal aperture dynamics

    NASA Astrophysics Data System (ADS)

    Ramos, Antônio M. T.; Prado, Carmen P. C.

    2013-01-01

    Stomata are pores responsible for gas exchange in leaves. Several experiments indicate that stomata synchronize into clusters or patches. The patches’ coordination may produce oscillations in stomatal conductance. Previous studies claim to reproduce some experimental results. However, none was able to explain the variety of behavior observed in the stomatal dynamics. Recently, Ferraz and Prado suggested a realistic geometry of vein distribution. Although it reproduces the patches, no oscillation was observed and the patches remain static. Without exploring significant details, the authors stated that hysteresis in stomatal aperture could explain several experimental features. In this paper, the hysteresis hypothesis is further explored through the concept of hysteretic operators. We have shown that the hysteresis assumption is sufficient to obtain dynamical patches and oscillations in stomatal conductance. The robustness of this hypothesis is tested by using different hysteresis operators. The model analysis reveals a dependence between the period of oscillation in stomatal conductance and the water deficit between the leaf and the environment. This underlying feature of the model might inspire further experiments to test this hypothesis.

  12. Experimenting with Sensor Webs Using Earth Observing 1

    NASA Technical Reports Server (NTRS)

    Mandl, Dan

    2004-01-01

    The New Millennium Program (NMP) Earth Observing 1 ( EO-1) satellite was launched November 21, 2000 as a one year technology validation mission. After an almost flawless first year of operations, EO-1 continued to operate in a test bed d e to validate additional technologies and concepts that will be applicable to future sensor webs. A sensor web is a group of sensors, whether space-based, ground-based or air plane-based which act in a collaborative autonomous manner to produce more value than would otherwise result from the individual observations.

  13. Experiences and Challenges in Earth Science Software Reuse

    NASA Astrophysics Data System (ADS)

    Werpy, J.

    2010-12-01

    The Land Processes Distributed Active Archive Center (LP DAAC) has faced many of the challenges common to organizations serving the Earth Science community’s growing needs for advanced data access interfaces and enhanced processing capabilities. Open source software has led to a growth in code reuse through many different software packages, where an open source layer serves as a basis of collaboration from which interfaces and systems with unprecedented flexibility, portability, and ease of integration have been constructed. LP DAAC adopts these open source foundations in its pursuit of code reuse as the most efficient method of meeting the challenges presented in the Earth Science community. Rather than relying on the traditional “grow your own” philosophy of software development, LP DAAC now focuses on determining which projects and initiatives will most benefit from code reuse. The implementation of a software reuse strategy at LP DAAC reduces the time, effort, and complexity of several projects. Facing technological challenges, enhanced interface requirements, and restrictive policy guidelines, LP DAAC identifies collaborative solutions and integrates them successfully into innovative projects. The MODIS Reprojection Tool for the Web (MRTWeb), the Cross-DAAC Access and New Distribution Interface (CANDI), and the Digital Elevation Model Explorer (DEMEX) respectively benefit from software reuse in achieving their objectives. The challenges, methods, and results from each of these collaborations with USGS Global Visualization Viewer (GloVis), Moderate Resolution Imaging Spectroradiometer (MODIS) Adaptive Processing System (MODAPS), and George Mason University (GMU) represent efficient utilization of a software reuse strategy at LP DAAC.

  14. Livingstone Model-Based Diagnosis of Earth Observing One Infusion Experiment

    NASA Technical Reports Server (NTRS)

    Hayden, Sandra C.; Sweet, Adam J.; Christa, Scott E.

    2004-01-01

    The Earth Observing One satellite, launched in November 2000, is an active earth science observation platform. This paper reports on the progress of an infusion experiment in which the Livingstone 2 Model-Based Diagnostic engine is deployed on Earth Observing One, demonstrating the capability to monitor the nominal operation of the spacecraft under command of an on-board planner, and demonstrating on-board diagnosis of spacecraft failures. Design and development of the experiment, specification and validation of diagnostic scenarios, characterization of performance results and benefits of the model- based approach are presented.

  15. Macroscopic theory for capillary-pressure hysteresis.

    PubMed

    Athukorallage, Bhagya; Aulisa, Eugenio; Iyer, Ram; Zhang, Larry

    2015-03-03

    In this article, we present a theory of macroscopic contact angle hysteresis by considering the minimization of the Helmholtz free energy of a solid-liquid-gas system over a convex set, subject to a constant volume constraint. The liquid and solid surfaces in contact are assumed to adhere weakly to each other, causing the interfacial energy to be set-valued. A simple calculus of variations argument for the minimization of the Helmholtz energy leads to the Young-Laplace equation for the drop surface in contact with the gas and a variational inequality that yields contact angle hysteresis for advancing/receding flow. We also show that the Young-Laplace equation with a Dirichlet boundary condition together with the variational inequality yields a basic hysteresis operator that describes the relationship between capillary pressure and volume. We validate the theory using results from the experiment for a sessile macroscopic drop. Although the capillary effect is a complex phenomenon even for a droplet as various points along the contact line might be pinned, the capillary pressure and volume of the drop are scalar variables that encapsulate the global quasistatic energy information for the entire droplet. Studying the capillary pressure versus volume relationship greatly simplifies the understanding and modeling of the phenomenon just as scalar magnetic hysteresis graphs greatly aided the modeling of devices with magnetic materials.

  16. Wetting hysteresis of nanodrops on nanorough surfaces.

    PubMed

    Chang, Cheng-Chung; Sheng, Yu-Jane; Tsao, Heng-Kwong

    2016-10-01

    Nanodrops on smooth or patterned rough surfaces are explored by many-body dissipative particle dynamics to demonstrate the influence of surface roughness on droplet wetting. On a smooth surface, nanodrops exhibit the random motion and contact angle hysteresis is absent. The diffusivity decays as the intrinsic contact angle (θ_{Y}) decreases. On a rough surface, the contact line is pinned and the most stable contact angle (θ_{Y}^{'}) is acquired. The extent of contact angle hysteresis (Δθ) is determined by two approaches, which resemble the inflation-deflation method and inclined plane method for experiments. The hysteresis loop is acquired and both approaches yield consistent results. The influences of wettability and surface roughness on θ_{Y}^{'} and Δθ are examined. θ_{Y}^{'} deviates from that estimated by the Wenzel or Cassie-Baxter models. This consequence can be explained by the extent of impregnation, which varies with the groove position and wettability. Moreover, contact angle hysteresis depends more on the groove width than the depth.

  17. Wetting hysteresis of nanodrops on nanorough surfaces

    NASA Astrophysics Data System (ADS)

    Chang, Cheng-Chung; Sheng, Yu-Jane; Tsao, Heng-Kwong

    2016-10-01

    Nanodrops on smooth or patterned rough surfaces are explored by many-body dissipative particle dynamics to demonstrate the influence of surface roughness on droplet wetting. On a smooth surface, nanodrops exhibit the random motion and contact angle hysteresis is absent. The diffusivity decays as the intrinsic contact angle (θY) decreases. On a rough surface, the contact line is pinned and the most stable contact angle (θY') is acquired. The extent of contact angle hysteresis (Δ θ ) is determined by two approaches, which resemble the inflation-deflation method and inclined plane method for experiments. The hysteresis loop is acquired and both approaches yield consistent results. The influences of wettability and surface roughness on θY' and Δ θ are examined. θY' deviates from that estimated by the Wenzel or Cassie-Baxter models. This consequence can be explained by the extent of impregnation, which varies with the groove position and wettability. Moreover, contact angle hysteresis depends more on the groove width than the depth.

  18. Big Earth Data: the Film, the Experience, and some Thoughts

    NASA Astrophysics Data System (ADS)

    Baumann, P.; Hoenig, H.

    2015-12-01

    Scientists have to get out of the ivory tower and tell society, which ultimately finances them, about their work, their results, and implications, be they good or bad. This is commonly accepted ethics. But how would you "tell society" at large what you are doing? Scientific work typically is difficult to confer to lay people, and finding suitable simplifications and paraphrasings requires considerable effort. Estimating societal implications is dangerous as swimming with sharks, some of which are your own colleagues. Media tend to be not always interested - unless results are particularly spectacular, well, in a press sense. Again, sharks are luring. All this makes informing the public a tedious, time-consuming task which tends to receive not much appreciation in tenure negotiations where indexed publications are the first and foremost measure.As part of the EU funded EarthServer initiative we tried it. Having promised a "video about the project" we found it boring to do another 10 minute repetition from the grant contract and started aiming at a full TV documentary explaining "Big Earth Data" to the interested citizens. It took more than one year to convince a TV producing company and TV stations that this is not another feature about the beauty of nature or catastrophies, but about human insight from computer-supported sifting through all those observations and simulations available. After they got the gist they were fully on board and supported financially with a substantial amount. The final 53 minutes "Big Earth Data" movie was broadcast in February 2015 in German and French (English version available from ). Several smaller spin-off features originated around it, such as an uptake of the theme (and material) in a popular German science TV series.Of course, this is but one contribution and cannot be made a continuous activity. In the talk we want to present and discuss the "making of" from a scientist's perspective, highlighting the ups and downs in the

  19. Big Earth Data: the Film, the Experience, and some Thoughts

    NASA Astrophysics Data System (ADS)

    Baumann, P.

    2016-12-01

    Scientists have to get out of the ivory tower and tell society, which ultimately finances them, about their work, their results, and implications, be they good or bad. This is commonly accepted ethics. But how would you "tell society" at large what you are doing? Scientific work typically is difficult to confer to lay people, and finding suitable simplifications and paraphrasings requires considerable effort. Estimating societal implications is dangerous as swimming with sharks, some of which are your own colleagues. Media tend to be not always interested - unless results are particularly spectacular, well, in a press sense. Again, sharks are luring. All this makes informing the public a tedious, time-consuming task which tends to receive not much appreciation in tenure negotiations where indexed publications are the first and foremost measure.As part of the EU funded EarthServer initiative we tried it. Having promised a "video about the project" we found it boring to do another 10 minute repetition from the grant contract and started aiming at a full TV documentary explaining "Big Earth Data" to the interested citizens. It took more than one year to convince a TV producing company and TV stations that this is not another feature about the beauty of nature or catastrophies, but a bout human insight from computer-supported sifting through all those observations and simulations available. After they got the gist they were fully on board and supported financially with a substantial amount. The final 53 minutes "Big Earth Data" movie was broadcast in February 2015 in German and French (English version available from ). Several smaller spin-off features originated around it, such as an uptake of the theme (and material) in a popular German science TV series.Of course, this is but one contribution and cannot be made a continuous activity. In the talk we want to present and discuss the "making of" from a scientist's perspective, highlighting the ups and downs in the

  20. Earth

    NASA Image and Video Library

    2012-01-30

    Behold one of the more detailed images of the Earth yet created. This Blue Marble Earth montage shown above -- created from photographs taken by the Visible/Infrared Imager Radiometer Suite (VIIRS) instrument on board the new Suomi NPP satellite -- shows many stunning details of our home planet. The Suomi NPP satellite was launched last October and renamed last week after Verner Suomi, commonly deemed the father of satellite meteorology. The composite was created from the data collected during four orbits of the robotic satellite taken earlier this month and digitally projected onto the globe. Many features of North America and the Western Hemisphere are particularly visible on a high resolution version of the image. http://photojournal.jpl.nasa.gov/catalog/PIA18033

  1. Thermal hysteresis proteins.

    PubMed

    Barrett, J

    2001-02-01

    Extreme environments present a wealth of biochemical adaptations. Thermal hysteresis proteins (THPs) have been found in vertebrates, invertebrates, plants, bacteria and fungi and are able to depress the freezing point of water (in the presence of ice crystals) in a non-colligative manner by binding to the surface of nascent ice crystals. The THPs comprise a disparate group of proteins with a variety of tertiary structures and often no common sequence similarities or structural motifs. Different THPs bind to different faces of the ice crystal, and no single mechanism has been proposed to account for THP ice binding affinity and specificity. Experimentally THPs have been used in the cryopreservation of tissues and cells and to induce cold tolerance in freeze susceptible organisms. THPs represent a remarkable example of parallel and convergent evolution with different proteins being adapted for an anti-freeze role.

  2. Vortex flow hysteresis

    NASA Technical Reports Server (NTRS)

    Cunningham, A. M., Jr.

    1986-01-01

    An experimental study was conducted to quantify the hysteresis associated with various vortex flow transition points and to determine the effect of planform geometry. The transition points observed consisted of the appearance (or disappearance) of trailing edge vortex burst and the transition to (or from) flat plate or totally separated flows. Flow visualization with smoke injected into the vortices was used to identify the transitions on a series of semi-span models tested in a low speed tunnel. The planforms tested included simple deltas (55 deg to 80 deg sweep), cranked wings with varying tip panel sweep and dihedral, and a straked wing. High speed movies at 1000 frames per second were made of the vortex flow visualization in order to better understand the dynamics of vortex flow, burst and transition.

  3. Characterization of Corneal Indentation Hysteresis.

    PubMed

    Ko, Match W L; Dongming Wei; Leung, Christopher K S

    2015-01-01

    Corneal indentation is adapted for the design and development of a characterization method for corneal hysteresis behavior - Corneal Indentation Hysteresis (CIH). Fourteen porcine eyes were tested using the corneal indentation method. The CIH measured in enucleated porcine eyes showed indentation rate and intraocular pressure (IOP) dependences. The CIH increased with indentation rate at lower IOP (<; 25 mmHg) and decreased with indentation rate at higher IOP (> 25 mmHg). The CIH was linear proportional to the IOP within an individual eye. The CIH was positively correlated with the IOP, corneal in-plane tensile stress and corneal tangent modulus (E). A new method based on corneal indentation for the measurement of Corneal Indentation Hysteresis in vivo is developed. To our knowledge, this is the first study to introduce the corneal indentation hysteresis and correlate the corneal indentation hysteresis and corneal tangent modulus.

  4. Semi-empirical modeling of hysteresis compensation in magnetostrictive actuator

    NASA Astrophysics Data System (ADS)

    Ji, Ki-Hyun; Park, Hae-Jung; Park, Young-Woo; Wereley, Norman M.

    2013-04-01

    Hysteresis causes a delayed response to a given input in a magnetostrictive actuator (MA). It becomes critical when the MA has to be controlled in precise and real-time mode. An efficient way to compensate hysteresis must be considered. The Jiles-Atherton and Preisach models have been applied mostly in the literature, but these models need complex mathematics that makes them difficult to be applied in precise and real-time mode. Thus, this paper presents a semi-empirical model to compensate hysteresis in the MA. The idea comes from the similarity of the shapes between the hysteresis-compensated input voltage to the MA, and the output voltage of R-C circuit. The respective hysteresis-compensated input voltage and R-C circuit are expressed as polynomial and exponential equations, resulting in two closed-form equations about capacitance. One set of capacitance values for each frequency is selected by simulating the derived equations. Experiments are performed to choose one capacitance value among a set of capacitance values from simulation, based on trial-and-error. The concept of the hysteresis loss is introduced and defined as the ratio of areas between the hysteretic and reference curves. It is observed that the percent change of hysteresis loss increases as the frequency increases up to 400 Hz, but decreases with further increase of the frequency up to 800 Hz. It can be concluded that the proposed approach is effective to compensate hysteresis in the MA, and that hysteresis loss definition introduced by us can be used as a helpful measure of hysteresis compensation.

  5. Manifestations of the Rotation and Gravity of the Earth in Spin Physics Experiments

    NASA Astrophysics Data System (ADS)

    Obukhov, Yuri N.; Silenko, Alexander J.; Teryaev, Oleg V.

    An influence of the rotation and gravity of the Earth on the particle motion and the spin evolution is not negligible and it should be taken into account in spin physics experiments. The Earth rotation brings the Coriolis and centrifugal forces in the lab frame and also manifests in the additional rotation of the spin and in the change of the Maxwell electrodynamics. The change of the Maxwell electrodynamics due to the Earth gravity is much smaller and can be neglected. One of manifestations of the Earth rotation is the Sagnac effect. The electric and magnetic fields acting on the spin in the Earth's rotating frame coincide with the corresponding fields determined in the inertial frame instantly accompanying a lab. The effective electric field governing the particle motion differs from the electric field in the instantly accompanying frame. Nevertheless, the difference between the conventional Lorentz force and the actual force in the Earth's rotating frame vanishes on average in accelerators and storage rings due to the beam rotation. The Earth gravity manifests in additional forces acting on particles/nuclei and in additional torques acting on the spin. The additional forces are the Newton-like force and the reaction force provided by a focusing system. The additional torques are caused by the corresponding focusing field and by the geodetic effect. As a result, the Earth gravity leads to the additional spin rotation about the radial axis which may not be negligible in EDM experiments.

  6. A Numerical Experiment to Test the Influence of the Uncertainty of Earth Model on Nutation

    NASA Astrophysics Data System (ADS)

    Huang, C. L.; Zhang, M.

    2014-12-01

    From an infinite set of coupled ordinary differential equations that govern the infinitesimal elastic-gravitational oscillations of a rotating, slightly elliptical Earth, as well as a set of boundary conditions on displacement vector, stress tensor and gravity potential, the theoretical nutation model of non-rigid earth can be numerically obtained. In these differential equations and the boundary conditions, the distributions of density and elastic (Lame) parameters interior the Earth are key parameters and are usually input from 1D earth model like PREM. However, the influence of the uncertainty of a given earth model on nutation has never been checked. In this work, we made a numerical experiment to test it, and some primary results will be presented.

  7. Manifestations of the rotation and gravity of the Earth in high-energy physics experiments

    NASA Astrophysics Data System (ADS)

    Obukhov, Yuri N.; Silenko, Alexander J.; Teryaev, Oleg V.

    2016-08-01

    The inertial (due to rotation) and gravitational fields of the Earth affect the motion of an elementary particle and its spin dynamics. This influence is not negligible and should be taken into account in high-energy physics experiments. Earth's influence is manifest in perturbations in the particle motion, in an additional precession of the spin, and in a change of the constitutive tensor of the Maxwell electrodynamics. Bigger corrections are oscillatory, and their contributions average to zero. Other corrections due to the inhomogeneity of the inertial field are not oscillatory but they are very small and may be important only for the storage ring electric dipole moment experiments. Earth's gravity causes the Newton-like force, the reaction force provided by a focusing system, and additional torques acting on the spin. However, there are no observable indications of the electromagnetic effects due to Earth's gravity.

  8. Study of the effect of cloud inhomogeneity on the earth radiation budget experiment

    NASA Technical Reports Server (NTRS)

    Smith, Phillip J.

    1988-01-01

    The Earth Radiation Budget Experiment (ERBE) is the most recent and probably the most intensive mission designed to gather precise measurements of the Earth's radiation components. The data obtained from ERBE is of great importance for future climatological studies. A statistical study reveals that the ERBE scanner data are highly correlated and that instantaneous measurements corresponding to neighboring pixels contain almost the same information. Analyzing only a fraction of the data set when sampling is suggested and applications of this strategy are given in the calculation of the albedo of the Earth and of the cloud-forcing over ocean.

  9. Review of Low Earth Orbital (LEO) flight experiments

    NASA Technical Reports Server (NTRS)

    Leger, L.; Santosmason, B.; Visentine, J.; Kuminecz, J.

    1987-01-01

    The atomic oxygen flux exposure experiments flown on Space Shuttle flights STS-5 and STS-8 are described along with the results of measurements made on hardware returned from the Solar Maximum repair mission (Space Shuttle flight 41-C). In general, these experiments have essentially provided for passive exposure of samples to oxygen fluences of approximately 1 to 3.5 x 10(20) atoms/sq cm. Atmospheric density is used to derive fluence and is dependent on solar activity, which has been on the decline side of the 11-year cycle. Thus, relatively low flight altitudes of less than 300 km were used to acquire these exposures. After exposure, the samples were analyzed using various methods ranging from mass loss to extensive scanning electron microscopy and surface analysis techniques. Results are summarized and implications for the space station are discussed.

  10. Earth Radiation Budget Experiment (ERBE) Data Sets for Global Environment and Climate Change Studies

    NASA Technical Reports Server (NTRS)

    Bess, T. Dale; Carlson, Ann B.; Denn, Fredrick M.

    1997-01-01

    For a number of years there has been considerable interest in the earth's radiation budget (ERB) or energy balance, and entails making the best measurements possible of absorbed solar radiation, reflected shortwave radiation (RSW), thermal outgoing longwave radiation (OLR), and net radiation. ERB data are fundamental to the development of realistic climate models and studying natural and anthropogenic perturbations of the climate. Much of the interest and investigations in the earth's energy balance predated the age of earth-orbiting satellites (Hunt et al., 1986). Beginning in the mid 1960's earth-orbiting satellites began to play an important role in making measurements of the earth's radiation flux although much effort had gone into measuring ERB parameters prior to 1960 (House et al., 1986). Beginning in 1974 and extending until the present time, three different satellite experiments (not all operating at the same time) have been making radiation budget measurements almost continually in time. Two of the experiments were totally dedicated to making radiation budget measurements of the earth, and the other experiment flown on NOAA sun-synchronous AVHRR weather satellites produced radiation budget parameters as a by-product. The heat budget data from the AVHRR satellites began collecting data in June 1974 and have operated almost continuously for 23 years producing valuable data for long term climate monitoring.

  11. Earth Radiation Budget Experiment (ERBE) Data Sets for Global Environment and Climate Change Studies

    NASA Technical Reports Server (NTRS)

    Bess, T. Dale; Carlson, Ann B.; Denn, Fredrick M.

    1997-01-01

    For a number of years there has been considerable interest in the earth's radiation budget (ERB) or energy balance, and entails making the best measurements possible of absorbed solar radiation, reflected shortwave radiation (RSW), thermal outgoing longwave radiation (OLR), and net radiation. ERB data are fundamental to the development of realistic climate models and studying natural and anthropogenic perturbations of the climate. Much of the interest and investigations in the earth's energy balance predated the age of earth-orbiting satellites (Hunt et al., 1986). Beginning in the mid 1960's earth-orbiting satellites began to play an important role in making measurements of the earth's radiation flux although much effort had gone into measuring ERB parameters prior to 1960 (House et al., 1986). Beginning in 1974 and extending until the present time, three different satellite experiments (not all operating at the same time) have been making radiation budget measurements almost continually in time. Two of the experiments were totally dedicated to making radiation budget measurements of the earth, and the other experiment flown on NOAA sun-synchronous AVHRR weather satellites produced radiation budget parameters as a by-product. The heat budget data from the AVHRR satellites began collecting data in June 1974 and have operated almost continuously for 23 years producing valuable data for long term climate monitoring.

  12. Wetting Hysteresis at the Molecular Scale

    NASA Technical Reports Server (NTRS)

    Jin, Wei; Koplik, Joel; Banavar, Jayanth R.

    1996-01-01

    The motion of a fluid-fluid-solid contact line on a rough surface is well known to display hysteresis in the contact angle vs. velocity relationship. In order to understand the phenomenon at a fundamental microscopic level, we have conducted molecular dynamics computer simulations of a Wilhelmy plate experiment in which a solid surface is dipped into a liquid bath, and the force-velocity characteristics are measured. We directly observe a systematic variation of force and contact angle with velocity, which is single-valued for the case of an atomically smooth solid surface. In the microscopically rough case, however, we find (as intuitively expected) an open hysteresis loop. Further characterization of the interface dynamics is in progress.

  13. Mach, methodology, hysteresis and economics

    NASA Astrophysics Data System (ADS)

    Cross, R.

    2008-11-01

    This methodological note examines the epistemological foundations of hysteresis with particular reference to applications to economic systems. The economy principles of Ernst Mach are advocated and used in this assessment.

  14. Revealing the Earth's mantle from the tallest mountains using the Jinping Neutrino Experiment.

    PubMed

    Šrámek, Ondřej; Roskovec, Bedřich; Wipperfurth, Scott A; Xi, Yufei; McDonough, William F

    2016-09-09

    The Earth's engine is driven by unknown proportions of primordial energy and heat produced in radioactive decay. Unfortunately, competing models of Earth's composition reveal an order of magnitude uncertainty in the amount of radiogenic power driving mantle dynamics. Recent measurements of the Earth's flux of geoneutrinos, electron antineutrinos from terrestrial natural radioactivity, reveal the amount of uranium and thorium in the Earth and set limits on the residual proportion of primordial energy. Comparison of the flux measured at large underground neutrino experiments with geologically informed predictions of geoneutrino emission from the crust provide the critical test needed to define the mantle's radiogenic power. Measurement at an oceanic location, distant from nuclear reactors and continental crust, would best reveal the mantle flux, however, no such experiment is anticipated. We predict the geoneutrino flux at the site of the Jinping Neutrino Experiment (Sichuan, China). Within 8 years, the combination of existing data and measurements from soon to come experiments, including Jinping, will exclude end-member models at the 1σ level, define the mantle's radiogenic contribution to the surface heat loss, set limits on the composition of the silicate Earth, and provide significant parameter bounds for models defining the mode of mantle convection.

  15. Mastering hysteresis in magnetocaloric materials

    PubMed Central

    Gottschall, T.; Fries, M.; Benke, D.; Radulov, I.; Skokov, K. P.; Wende, H.; Gruner, M.; Acet, M.; Entel, P.; Farle, M.

    2016-01-01

    Hysteresis is more than just an interesting oddity that occurs in materials with a first-order transition. It is a real obstacle on the path from existing laboratory-scale prototypes of magnetic refrigerators towards commercialization of this potentially disruptive cooling technology. Indeed, the reversibility of the magnetocaloric effect, being essential for magnetic heat pumps, strongly depends on the width of the thermal hysteresis and, therefore, it is necessary to understand the mechanisms causing hysteresis and to find solutions to minimize losses associated with thermal hysteresis in order to maximize the efficiency of magnetic cooling devices. In this work, we discuss the fundamental aspects that can contribute to thermal hysteresis and the strategies that we are developing to at least partially overcome the hysteresis problem in some selected classes of magnetocaloric materials with large application potential. In doing so, we refer to the most relevant classes of magnetic refrigerants La–Fe–Si-, Heusler- and Fe2P-type compounds. This article is part of the themed issue ‘Taking the temperature of phase transitions in cool materials’. PMID:27402928

  16. Mastering hysteresis in magnetocaloric materials.

    PubMed

    Gutfleisch, O; Gottschall, T; Fries, M; Benke, D; Radulov, I; Skokov, K P; Wende, H; Gruner, M; Acet, M; Entel, P; Farle, M

    2016-08-13

    Hysteresis is more than just an interesting oddity that occurs in materials with a first-order transition. It is a real obstacle on the path from existing laboratory-scale prototypes of magnetic refrigerators towards commercialization of this potentially disruptive cooling technology. Indeed, the reversibility of the magnetocaloric effect, being essential for magnetic heat pumps, strongly depends on the width of the thermal hysteresis and, therefore, it is necessary to understand the mechanisms causing hysteresis and to find solutions to minimize losses associated with thermal hysteresis in order to maximize the efficiency of magnetic cooling devices. In this work, we discuss the fundamental aspects that can contribute to thermal hysteresis and the strategies that we are developing to at least partially overcome the hysteresis problem in some selected classes of magnetocaloric materials with large application potential. In doing so, we refer to the most relevant classes of magnetic refrigerants La-Fe-Si-, Heusler- and Fe2P-type compounds.This article is part of the themed issue 'Taking the temperature of phase transitions in cool materials'. © 2016 The Author(s).

  17. Manifestations of the rotation and gravity of the Earth in spin physics experiments

    NASA Astrophysics Data System (ADS)

    Obukhov, Yuri N.; Silenko, Alexander J.; Teryaev, Oleg V.

    2016-10-01

    An influence of the rotation and gravity of the Earth on the particle motion and the spin evolution is not negligible and it should be taken into account in spin physics experiments. The Earth rotation brings the Coriolis and centrifugal forces in the lab frame and also manifests in the additional rotation of the spin and in the change of the Maxwell electrodynamics. The change of the Maxwell electrodynamics due to the Earth gravity is much smaller and can be neglected. One of manifestations of the Earth rotation is the Sagnac effect. The electric and magnetic fields acting on the spin in the Earth’s rotating frame coincide with the corresponding fields determined in the inertial frame instantly accompanying a lab. The effective electric field governing the particle motion differs from the electric field in the instantly accompanying frame. Nevertheless, the difference between the conventional Lorentz force and the actual force in the Earth’s rotating frame vanishes on average in accelerators and storage rings due to the beam rotation. The Earth gravity manifests in additional forces acting on particles/nuclei and in additional torques acting on the spin. The additional forces are the Newton-like force and the reaction force provided by a focusing system. The additional torques are caused by the corresponding focusing field and by the geodetic effect. As a result, the Earth gravity leads to the additional spin rotation about the radial axis which may not be negligible in EDM experiments.

  18. Passive exposure of Earth radiation budget experiment components. LDEF experiment AO-147: Post-flight examinations and tests

    NASA Technical Reports Server (NTRS)

    Hickey, John R.

    1992-01-01

    The flight spare sensors of the Earth Radiation Budget (ERB) experiment of the Nimbus 6 and 7 missions were flown aboard the LDEF. The preliminary post retrieval examination and test results are presented here for the sensor windows and filters, the thermopile sensors and a cavity radiometer.

  19. Perovskite-fullerene hybrid materials suppress hysteresis in planar diodes.

    PubMed

    Xu, Jixian; Buin, Andrei; Ip, Alexander H; Li, Wei; Voznyy, Oleksandr; Comin, Riccardo; Yuan, Mingjian; Jeon, Seokmin; Ning, Zhijun; McDowell, Jeffrey J; Kanjanaboos, Pongsakorn; Sun, Jon-Paul; Lan, Xinzheng; Quan, Li Na; Kim, Dong Ha; Hill, Ian G; Maksymovych, Peter; Sargent, Edward H

    2015-05-08

    Solution-processed planar perovskite devices are highly desirable in a wide variety of optoelectronic applications; however, they are prone to hysteresis and current instabilities. Here we report the first perovskite-PCBM hybrid solid with significantly reduced hysteresis and recombination loss achieved in a single step. This new material displays an efficient electrically coupled microstructure: PCBM is homogeneously distributed throughout the film at perovskite grain boundaries. The PCBM passivates the key PbI3(-) antisite defects during the perovskite self-assembly, as revealed by theory and experiment. Photoluminescence transient spectroscopy proves that the PCBM phase promotes electron extraction. We showcase this mixed material in planar solar cells that feature low hysteresis and enhanced photovoltage. Using conductive AFM studies, we reveal the memristive properties of perovskite films. We close by positing that PCBM, by tying up both halide-rich antisites and unincorporated halides, reduces electric field-induced anion migration that may give rise to hysteresis and unstable diode behaviour.

  20. Perovskite-Fullerene Hybrid Materials Eliminate Hysteresis In Planar Diodes

    SciTech Connect

    Xu, Jixian; Buin, Andrei; Ip, Alexander H.; Li, Wei; Voznyy, Oleksandr; Comin, Riccardo; Yuan, Mingjian; Jeon, Seokmin; Ning, Zhijun; McDowell, Jeffrey; Kanjanaboos, Pongsakorn; Sun, Jon-Paul; Lan, Xinzheng; Quan, Li Na; Kim, Dong Ha; Hill, Ian; Maksymovych, Petro; Sargent, Edward H.

    2015-03-31

    Solution-processed planar perovskite devices are highly desirable in a wide variety of optoelectronic applications; however, they are prone to hysteresis and current instabilities. Here we report the first perovskite–PCBM hybrid solid with significantly reduced hysteresis and recombination loss achieved in a single step. This new material displays an efficient electrically coupled microstructure: PCBM is homogeneously distributed throughout the film at perovskite grain boundaries. The PCBM passivates the key PbI3 antisite defects during the perovskite self-assembly, as revealed by theory and experiment. Photoluminescence transient spectroscopy proves that the PCBM phase promotes electron extraction. We showcase this mixed material in planar solar cells that feature low hysteresis and enhanced photovoltage. Using conductive AFM studies, we reveal the memristive properties of perovskite films. We close by positing that PCBM, by tying up both halide-rich antisites and unincorporated halides, reduces electric field-induced anion migration that may give rise to hysteresis and unstable diode behaviour.

  1. Design of experiment for earth rotation and baseline parameter determination from very long baseline interferometry

    NASA Technical Reports Server (NTRS)

    Dermanis, A.

    1977-01-01

    The possibility of recovering earth rotation and network geometry (baseline) parameters are emphasized. The numerical simulated experiments performed are set up in an environment where station coordinates vary with respect to inertial space according to a simulated earth rotation model similar to the actual but unknown rotation of the earth. The basic technique of VLBI and its mathematical model are presented. The parametrization of earth rotation chosen is described and the resulting model is linearized. A simple analysis of the geometry of the observations leads to some useful hints on achieving maximum sensitivity of the observations with respect to the parameters considered. The basic philosophy for the simulation of data and their analysis through standard least squares adjustment techniques is presented. A number of characteristic network designs based on present and candidate station locations are chosen. The results of the simulations for each design are presented together with a summary of the conclusions.

  2. Modeling and characterization of the Earth Radiation Budget Experiment (ERBE) nonscanner and scanner sensors

    NASA Technical Reports Server (NTRS)

    Halyo, Nesim; Pandey, Dhirendra K.; Taylor, Deborah B.

    1989-01-01

    The Earth Radiation Budget Experiment (ERBE) is making high-absolute-accuracy measurements of the reflected solar and Earth-emitted radiation as well as the incoming solar radiation from three satellites: ERBS, NOAA-9, and NOAA-10. Each satellite has four Earth-looking nonscanning radiometers and three scanning radiometers. A fifth nonscanner, the solar monitor, measures the incoming solar radiation. The development of the ERBE sensor characterization procedures are described using the calibration data for each of the Earth-looking nonscanners and scanners. Sensor models for the ERBE radiometers are developed including the radiative exchange, conductive heat flow, and electronics processing for transient and steady state conditions. The steady state models are used to interpret the sensor outputs, resulting in the data reduction algorithms for the ERBE instruments. Both ground calibration and flight calibration procedures are treated and analyzed. The ground and flight calibration coefficients for the data reduction algorithms are presented.

  3. Hysteresis and fast timescales in transport relations of toroidal plasmas

    NASA Astrophysics Data System (ADS)

    Itoh, K.; Itoh, S.-I.; Ida, K.; Inagaki, S.; Kamada, Y.; Kamiya, K.; Dong, J. Q.; Hidalgo, C.; Evans, T.; Ko, W. H.; Park, H.; Tokuzawa, T.; Kubo, S.; Kobayashi, T.; Kosuga, Y.; Sasaki, M.; Yun, G. S.; Song, S. D.; Kasuya, N.; Nagashima, Y.; Moon, C.; Yoshinuma, M.; Makino, R.; Tsujimura, T.; Tsuchiya, H.; Stroth, U.

    2017-10-01

    This article assesses current understanding of hysteresis in transport relations, and its impact on the field. The rapid changes of fluxes compared to slow changes of plasma parameters are overviewed for both core and edge plasmas. The modulation ECH experiment is explained, in which the heating power cycles on-and-off periodically, revealing hysteresis and fast changes in the gradient-flux relation. The key finding is that hystereses were observed simultaneously in both the the gradient-flux and gradient-fluctuation relations. Hysteresis with rapid timescale exists in the channels of energy, electron and impurity densities, and plausibly in momentum. Advanced methods of data analysis are explained. Transport hysteresis can be studied by observing the higher harmonics of temperature perturbation δ Tm in heating modulation experiments. The hysteresis introduces the term δ Tm , which depends on the harmonic number m in an algebraic manner (not exponential decay). Next, the causes of hysteresis and its fast timescale are discussed. The nonlocal-in-space coupling works here, but does not suffice. One mechanism for ‘the heating heats turbulence’ is that the external source S in phase space for heating has its fluctuation in turbulent plasma. This coupling can induce the direct input of heating power into fluctuations. The height of the jump in transport hysteresis is smaller for heavier hydrogen isotopes, and could be one of the origins of isotope effects on confinement. Finally, the impacts of transport hysteresis on the control system are assessed. Control systems must be designed so as to protect the system from sudden plasma loss.

  4. Thermal and orbital analysis of Earth monitoring Sun-synchronous space experiments

    NASA Technical Reports Server (NTRS)

    Killough, Brian D.

    1990-01-01

    The fundamentals of an Earth monitoring Sun-synchronous orbit are presented. A Sun-synchronous Orbit Analysis Program (SOAP) was developed to calculate orbital parameters for an entire year. The output from this program provides the required input data for the TRASYS thermal radiation computer code, which in turn computes the infrared, solar and Earth albedo heat fluxes incident on a space experiment. Direct incident heat fluxes can be used as input to a generalized thermal analyzer program to size radiators and predict instrument operating temperatures. The SOAP computer code and its application to the thermal analysis methodology presented, should prove useful to the thermal engineer during the design phases of Earth monitoring Sun-synchronous space experiments.

  5. Data analysis and software support for the Earth radiation budget experiment

    NASA Technical Reports Server (NTRS)

    Edmonds, W.; Natarajan, S.

    1987-01-01

    Computer programming and data analysis efforts were performed in support of the Earth Radiation Budget Experiment (ERBE) at NASA/Langley. A brief description of the ERBE followed by sections describing software development and data analysis for both prelaunch and postlaunch instrument data are presented.

  6. An Experience of Science Theatre to Introduce Earth Interior and Natural Hazards to Children

    ERIC Educational Resources Information Center

    Musacchio, Gemma; Lanza, Tiziana; D'Addezio, Giuliana

    2015-01-01

    The present paper describes an experience of science theatre addressed to children of primary and secondary school, with the main purpose of making them acquainted with a topic, the interior of the Earth, largely underestimated in compulsory school curricula worldwide. A not less important task was to encourage a positive attitude towards natural…

  7. Through-the-earth communication: Experiment results from Billie Mine and Mississippi Chemical Mine

    NASA Astrophysics Data System (ADS)

    Buettner, H. M.; Didwall, E. M.; Bukofzer, D. C.

    1988-06-01

    As part of the Lawrence Livermore National Laboratory (LLNL) effort to evaluate Through-the-Earth Communication (TEC) as an option for military communication systems, experiments were conducted involving transmission, reception, and performance monitoring of digital electromagnetic communication signals propagating through the earth. The two experiments reported on here not only demonstrated that TEC is useful for transmissions at digital rates above a few bits per second, but also provided data on performance parameters with which to evaluate TEC in various military applications. The most important aspect of these experiments is that the bit error rate (BER) is measured rather than just estimated from purely analytic developments. By measuring this important parameter, not only has more credibility been lent to the proof of concept goals of the experiment, but also a means for judging the effects of assumptions in BER theoretical models has been provided.

  8. Inflated concepts for the earth science geostationary platform and an associated flight experiment

    NASA Technical Reports Server (NTRS)

    Friese, G.

    1992-01-01

    Large parabolic reflectors and solar concentrators are of great interest for microwave transmission, solar powered rockets, and Earth observations. Collector subsystems have been under slow development for a decade. Inflated paraboloids have a great weight and package volume advantage over mechanically erected systems and, therefore, have been receiving greater attention recently. The objective of this program was to produce a 'conceptual definition of an experiment to assess in-space structural damping characteristics and effects of the space meteoroid environment upon structural integrity and service life of large inflatable structures.' The flight experiment was to have been based upon an inflated solar concentration, but much of that was being done on other programs. To avoid redundancy, the Earth Science Geostationary Platform (ESGP) was selected as a focus mission for the experiment. Three major areas were studied: the ESGP reflector configuration; flight experiment; and meteoroids.

  9. Urban fifth graders' connections-making between formal earth science content and their lived experiences

    NASA Astrophysics Data System (ADS)

    Brkich, Katie Lynn

    2014-03-01

    Earth science education, as it is traditionally taught, involves presenting concepts such as weathering, erosion, and deposition using relatively well-known examples—the Grand Canyon, beach erosion, and others. However, these examples—which resonate well with middle- and upper-class students—ill-serve students of poverty attending urban schools who may have never traveled farther from home than the corner store. In this paper, I explore the use of a place-based educational framework in teaching earth science concepts to urban fifth graders and explore the connections they make between formal earth science content and their lived experiences using participant-driven photo elicitation techniques. I argue that students are able to gain a sounder understanding of earth science concepts when they are able to make direct observations between the content and their lived experiences and that when such direct observations are impossible they make analogies of appearance, structure, and response to make sense of the content. I discuss additionally the importance of expanding earth science instruction to include man-made materials, as these materials are excluded traditionally from the curriculum yet are most immediately available to urban students for examination.

  10. Radiation Information for Designing and Interpreting Biological Experiments Onboard Missions Beyond Low Earth Orbit

    NASA Technical Reports Server (NTRS)

    Straume, T.; Slaba, T.; Bhattacharya, S.; Braby, L. A.

    2017-01-01

    There is growing interest in flying biological experiments beyond low-Earth orbit (LEO) to measure biological responses potentially relevant to those expected during a human mission to Mars. Such experiments could be payloads onboard precursor missions, including unmanned private-public partnerships, as well as small low-cost spacecraft (satellites) designed specifically for biosentinel type missions. Designing such experiments requires knowledge of the radiation environment and its interactions with both the spacecraft and the experimental payload. Information is provided here that is useful for designing such experiments.

  11. From Earth to Heaven: Using `Newton's Cannon' Thought Experiment for Teaching Satellite Physics

    NASA Astrophysics Data System (ADS)

    Velentzas, Athanasios; Halkia, Krystallia

    2013-10-01

    Thought Experiments are powerful tools in both scientific thinking and in the teaching of science. In this study, the historical Thought Experiment (TE) `Newton's Cannon' was used as a tool to teach concepts relating to the motion of satellites to students at upper secondary level. The research instruments were: (a) a teaching-interview designed and implemented according to the Teaching Experiment methodology and (b) an open-ended questionnaire administered to students 2 weeks after the teaching-interview. The sample consisted of forty students divided into eleven groups. The teaching and learning processes which occurred during the teaching-interview were recorded and analyzed. The findings of the present study show that the use of the TE helped students to mentally construct a physical system which has nothing to do with their everyday experience (i.e. they had to imagine themselves as observers in a context in which the whole Earth was visible) and to draw conclusions about phenomena within this system. Specifically, students managed (1) to conclude that if an object is appropriately launched, it may be placed in an orbit around the Earth and to support this conclusion by giving necessary arguments, and (2) to realize that the same laws of physics describe, on the one hand, the motion of the Moon around the Earth (and the motion of other celestial bodies as well) and, on the other hand, the motion of `terrestrial' objects (i.e. objects on the Earth, such as a tennis ball). The main difficulties students met were caused by their idea that there is no gravity in the vacuum (i.e. the area outside of the Earth's atmosphere) and also by their everyday experience, according to which it is impossible for a projectile to move continuously parallel to the ground.

  12. Magnetic shielding in a low temperature torsion pendulum experiment. [superconducting cylinders for attenuation earth field

    NASA Technical Reports Server (NTRS)

    Phillips, P. R.

    1979-01-01

    A new type of ether drift experiment searches for anomalous torques on a permanent magnet. A torsion pendulum is used at liquid helium temperature, so that superconducting cylinders can be used to shield magnetic fields. Lead shields attenuate the earth's field, while Nb-Sn shields fastened to the pendulum contain the fields of the magnet. The paper describes the technique by which the earth's field can be reduced below 0.0001 G while simultaneously the moment of the magnet can be reduced by a factor 7 x 10 to the 4th.

  13. Balloon experiments in the earth's stratosphere within the ``Mars-96'' project

    NASA Astrophysics Data System (ADS)

    Kremnev, R. S.; Pichkhadze, K. M.; Zashchirinskii, A. M.; Pavlov, V. A.; Trifonov, I. V.; Linkin, V. M.; Kerzhanovich, V. V.; Nazarov, D. N.; Kotov, B. B.; Kotelnikov, K. A.; Polukhina, N. G.; Lepazg, G.-P.; Avrar, J.; Ortis, J.; Makartsev, O. V.; Sazonov, L. B.

    1996-03-01

    For experimental testing of a Mars balloon probe in the upper layers of the Earth's atmosphere a specified parachute system was developed, fabricated and tested in 3 high-altitude balloon flights. The balloon volumes were 130000 and 180000 m^3 with the payloads of 500 - 900 kg; the maximum flight altitude reached 32 km. The experiments showed that one-canopy parachute system with the area of 1200 m^2 has certain advantages as compared to the four-canopy system and can be used both in Mars balloon tests in the Earth's stratosphere and as a parachute system of the descent apparatus for investigation of Mars.

  14. Radiative Energy Budget Studies Using Observations from the Earth Radiation Budget Experiment (ERBE)

    NASA Technical Reports Server (NTRS)

    Ackerman, Steven A.; Frey, R.; Shie, M.; Olson, R.; Collimore, C.; Friedman, M.

    1997-01-01

    Our research activities under this NASA grant have focused on two broad topics associated with the Earth Radiation Budget Experiment (ERBE): (1) the role of clouds and the surface in modifying the radiative balance; and (2) the spatial and temporal variability of the earth's radiation budget. Each of these broad topics is discussed separately in the text that follows. The major points of the thesis are summarized in section 3 of this report. Other dissertation focuses on deriving the radiation budget over the TOGA COARE region.

  15. Earth-satellite-Earth laser long-path absorption experiment using the Retroreflector in Space (RIS) on the Advanced Earth Observing Satellite (ADEOS)

    NASA Astrophysics Data System (ADS)

    Sugimoto, Nobuo; Koga, Nobuhiko; Matsui, Ichiro; Sasano, Yasuhiro; Minato, Atsushi; Ozawa, Kenichi; Saito, Yasunori; Nomura, Akio; Aoki, Tetsuo; Itabe, Toshikazu; Kunimori, Hiroo; Murata, Isao; Fukunishi, Hiroshi

    1999-03-01

    This paper reports the results of the laser long-path absorption experiments carried out with the Retroreflector in Space (RIS) on the Advanced Earth Observing Satellite (ADEOS). The RIS is a 0.5 m diameter single-element hollow retroreflector with a unique optical design which uses a curved mirror surface to correct velocity aberrations caused by the satellite movement. In the RIS experiments a laser beam was transmitted from a ground station, reflected by the RIS, and received back at the ground station. The absorption of the intervening atmosphere was measured in the round-trip optical path. After the launch of the ADEOS in August 1996, the optical characteristics of the RIS were tested, and it was confirmed that the RIS worked well in orbit. The spectroscopic measurement was carried out with the single-longitudinal-mode TEA 1464-4258/1/2/015/img12 lasers by means of the method utilizing the Doppler shift of the reflected beam caused by the movement of the satellite. The spectrum of ozone was successfully measured in the 1464-4258/1/2/015/img13 region, and the measurement of the column contents of ozone was validated with the simultaneous heterodyne spectrometer measurement. In June 1997, however, the experiment with the RIS was discontinued due to the malfunction of the ADEOS solar paddle.

  16. Hysteresis zone or locus - Aerodynamic of bulbous based bodies at low speeds

    NASA Technical Reports Server (NTRS)

    Covert, E. E.

    1979-01-01

    Experimental data are presented which seem to suggest that a well-defined hysteresis locus on bulbous based bodies at low speeds does not exist. Instead, if the experiment is repeated several times, the entire hysteresis region seems to fill with data rather than trace out a specific hysteresis locus. Data obtained on an oscillating model even at low reduced frequencies may be well defined but when applied to arbitrary motion lead to less accurate results than desired.

  17. Earth orbital experiment program and requirements study, volume 1, sections 1 - 6

    NASA Technical Reports Server (NTRS)

    1971-01-01

    A reference manual for planners of manned earth-orbital research activity is presented. The manual serves as a systems approach to experiment and mission planning based on an integrated consideration of candidate research programs and the appropriate vehicle, mission, and technology development requirements. Long range goals and objectives for NASA activities during the 1970 to 1980 time period are analyzed. The useful and proper roles of manned and automated spacecraft for implementing NASA experiments are described. An integrated consideration of NASA long range goals and objectives, the system and mission requirements, and the alternative implementation plans are developed. Specific areas of investigation are: (1) manned space flight requirements, (2) space biology, (3) spaceborne astronomy, (4) space communications and navigation, (5) earth observation, (6) supporting technology development requirements, (7) data management system matrices, (8) instrumentation matrices, and (9) biotechnology laboratory experiments.

  18. Role of Surface Roughness in Hysteresis during Adhesive Elastic Contact.

    PubMed

    Kesari, Haneesh; Doll, Joseph C; Pruitt, Beth L; Cai, Wei; Lew, Adrian J

    2010-12-01

    In experiments that involve contact with adhesion between two surfaces, as found in atomic force microscopy or nanoindentation, two distinct contact force (P) vs. indentation-depth (h) curves are often measured depending on whether the indenter moves towards or away from the sample. The origin of this hysteresis is not well understood and is often attributed to moisture, plasticity or viscoelasticity. Here we report experiments that show that hysteresis can exist in the absence of these effects, and that its magnitude depends on surface roughness. We develop a theoretical model in which the hysteresis appears as the result of a series of surface instabilities, in which the contact area grows or recedes by a finite amount. The model can be used to estimate material properties from contact experiments even when the measured P-h curves are not unique.

  19. The NOAA-9 Earth Radiation Budget Experiment Wide Field-of-View Data Set

    NASA Technical Reports Server (NTRS)

    Bush, Kathryn A.; Smith, G. Louis; Young, David F.

    1999-01-01

    The Earth Radiation Budget Experiment (ERBE) consisted of wide field-of-view (WFOV) radiometers and scanning radiometers for measuring outgoing longwave radiation and solar radiation reflected from the Earth. These instruments were carried by the dedicated Earth Radiation Budget Satellite (ERBS) and by the NOAA-9 and -10 operational spacecraft. The WFOV radiometers provided data from which instantaneous fluxes at the top of the atmosphere (TOA) are computed by use of a numerical filter algorithm. Monthly mean fluxes over a 5-degree equal angle grid are computed from the instantaneous TOA fluxes. The WFOV radiometers aboard the NOAA-9 spacecraft operated from February 1985 through December 1992, at which time a failure of the shortwave radiometer ended the usable data after nearly 8 years. This paper examines the monthly mean products from that data set.

  20. The NOAA-9 Earth Radiation Budget Experiment Wide Field-of-View Data Set

    NASA Technical Reports Server (NTRS)

    Bush, Kathryn A.; Smith, G. Louis; Young, David F.

    1999-01-01

    The Earth Radiation Budget Experiment (ERBE) consisted of wide field-of-view (WFOV) radiometers and scanning radiometers for measuring outgoing longwave radiation and solar radiation reflected from the Earth. These instruments were carried by the dedicated Earth Radiation Budget Satellite (ERBS) and by the NOAA-9 and -10 operational spacecraft. The WFOV radiometers provided data from which instantaneous fluxes at the top of the atmosphere (TOA) are computed by use of a numerical filter algorithm. Monthly mean fluxes over a 5-degree equal angle grid are computed from the instantaneous TOA fluxes. The WFOV radiometers aboard the NOAA-9 spacecraft operated from February 1985 through December 1992, at which time a failure of the shortwave radiometer ended the usable data after nearly 8 years. This paper examines the monthly mean products from that data set.

  1. Causes and implications of colloid and microorganism retention hysteresis

    USDA-ARS?s Scientific Manuscript database

    Experiments were designed to better understand the causes and implications of colloid and microorganism retention hysteresis with transients in solution ionic strength (IS). Saturated packed column experiments were conducted using two sizes of carboxyl modified latex (CML) microspheres (0.1 and 1.1...

  2. Corporatising School Leadership through Hysteresis

    ERIC Educational Resources Information Center

    Courtney, Steven J.

    2017-01-01

    This article builds on the established notion that schools are hierarchised through policy, accruing different amounts and types of symbolic capital, by examining how this is reflected in the habitus of the leaders of new, privileged school types. The article uses Bourdieu's concept of hysteresis, or a dislocation between the habitus which…

  3. Nonlinear diffusion and superconducting hysteresis

    SciTech Connect

    Mayergoyz, I.D.

    1996-12-31

    Nonlinear diffusion of electromagnetic fields in superconductors with ideal and gradual resistive transitions is studied. Analytical results obtained for linear and nonlinear polarizations of electromagnetic fields are reported. These results lead to various extensions of the critical state model for superconducting hysteresis.

  4. [Dynamic wallpaper phenomenon and fusional hysteresis].

    PubMed

    Kondo, M; Nakamizo, S

    1982-12-01

    Two experiments were conducted with six and three subjects, respectively, to examine the "dynamic" wallpaper phenomenon in which the apparent location of a uniform repeating pattern shifted abruptly at a certain convergence distance when the pattern was viewed with the gradual change of convergence. Experiment 1 demonstrated that the critical convergence distances (shift points), at which the apparent location of the pattern shifted, differed between the two directions of the change of convergence, converging and diverging. It was greater in the diverging condition than in the converging condition. This fact shows a tendency to keep the same fusional state as far as possible when the convergence changes gradually. Experiment 2 showed that the difference of the critical convergence distance between the converging and diverging conditions is systematically related to the convergence level, that is, the difference increased as the convergence angle increased. The implications of the results of the two experiments were discussed in the context of the fusional hysteresis.

  5. Characteristics of the earth's radiation budget derived from the first year of data from the Earth Radiation Budget Experiment

    NASA Technical Reports Server (NTRS)

    Gibson, G. G.; Denn, F. M.; Young, D. F.; Harrison, E. F.; Minnis, P.; Barkstrom, B. R.

    1990-01-01

    The first year of broadband Earth Radiation Budget Experiment (ERBE) data is analyzed for top-of-the-atmosphere regional variations of outgoing longwave (LW) flux and planetary albedo for total scene as well as clear-sky conditions. The annual variation of radiative parameters is examined for February 1985 through January 1986 for selected regions, latitude zones, and the entire globe. Results show significant seasonal variations for both LW fluxes and albedo. A broad longwave flux maximum (with a relative minimum corresponding to the intertropical convergence zone in the middle) covers the tropics and the subtropics with its center moving about 20 deg in latitude between seasonal extremes. Minimum albedo (about 20 percent) occurs within 15 deg of the equator. In the tropics and midlatitudes, there is a tendency toward higher albedos during the summer. Larger albedos at the higher latitudes are caused by solar zenith angle effects and by increased snow and ice cover. Net warming occurs between 35 deg N and 35 deg S latitude near the equinoxes and in a 90-deg-wide latitude band at the solstices centered around 35 deg latitude in the summer hemisphere. This energy surplus at lower latitudes coupled with an energy deficit in the poleward regions is the primary driver of atmospheric circulations. For the year, the global net radiation is nearly in balance.

  6. Characteristics of the earth's radiation budget derived from the first year of data from the Earth Radiation Budget Experiment

    NASA Technical Reports Server (NTRS)

    Gibson, G. G.; Denn, F. M.; Young, D. F.; Harrison, E. F.; Minnis, P.; Barkstrom, B. R.

    1990-01-01

    The first year of broadband Earth Radiation Budget Experiment (ERBE) data is analyzed for top-of-the-atmosphere regional variations of outgoing longwave (LW) flux and planetary albedo for total scene as well as clear-sky conditions. The annual variation of radiative parameters is examined for February 1985 through January 1986 for selected regions, latitude zones, and the entire globe. Results show significant seasonal variations for both LW fluxes and albedo. A broad longwave flux maximum (with a relative minimum corresponding to the intertropical convergence zone in the middle) covers the tropics and the subtropics with its center moving about 20 deg in latitude between seasonal extremes. Minimum albedo (about 20 percent) occurs within 15 deg of the equator. In the tropics and midlatitudes, there is a tendency toward higher albedos during the summer. Larger albedos at the higher latitudes are caused by solar zenith angle effects and by increased snow and ice cover. Net warming occurs between 35 deg N and 35 deg S latitude near the equinoxes and in a 90-deg-wide latitude band at the solstices centered around 35 deg latitude in the summer hemisphere. This energy surplus at lower latitudes coupled with an energy deficit in the poleward regions is the primary driver of atmospheric circulations. For the year, the global net radiation is nearly in balance.

  7. Earth at Rest - Aesthetic Experience and Students' Grounding in Science Education

    NASA Astrophysics Data System (ADS)

    Østergaard, Edvin

    2017-07-01

    Focus of this article is the current situation characterized by students' de-rootedness and possible measures to improve the situation within the frame of education for sustainable development. My main line of argument is that science teachers can practice teaching in such a way that students are brought in deeper contact to the environment. I discuss efforts to promote aesthetic experience in science class and in science teacher education. Within a wide range of definitions, my main understanding of aesthetic experience is that of pre-conceptual experience, relational to the environment and incorporated in students' embodied knowledge. I ground the idea of Earth at rest in Husserl's phenomenological philosophy and Heidegger's notion of science' deprivation of the world. A critique of the ontological reversal leads to an ontological re-reversal that implies giving lifeworld experience back its value and rooting scientific concepts in students' everyday lives. Six aspects of facilitating grounding in sustainability-oriented science teaching and teacher education are highlighted and discussed: students' everyday knowledge and experience, aesthetic experience and grounding, fostering aesthetic sensibility, cross-curricular integration with art, ontological and epistemological aspects, and belongingness and (re-)connection to Earth. I conclude that both science students and student-teachers need to practice their sense of caring and belonging, as well as refining their sensibility towards the world. With an intension of educating for a sustainable development, there is an urgent need for a critical discussion in science education when it comes to engaging learners for a sustainable future.

  8. Passive exposure of Earth radiation budget experiment components LDEF experiment AO-147: Post-flight examinations and tests

    NASA Technical Reports Server (NTRS)

    Hickey, John R.

    1991-01-01

    The Passive Exposure of Earth Radiation Budget Experiment Components (PEERBEC) experiment of the Long Duration Exposure Facility (LDEF) mission was composed of sensors and components associated with the measurement of the earth radiation budget (ERB) from satellites. These components included the flight spare sensors from the ERB experiment which operated on Nimbus 6 and 7 satellites. The experiment components and materials as well as the pertinent background and ancillary information necessary for the understanding of the intended mission and the results are described. The extent and timing of the LDEF mission brought the exposure from solar minimum between cycles 21 and 22 through the solar maximum of cycle 22. The orbital decay, coupled with the events of solar maximum, caused the LDEF to be exposed to a broader range of space environmental effects than were anticipated. The mission spanned almost six years concurrent with the 12 year (to date) Nimbus 7 operations. Preliminary information is presented on the following: (1) the changes in transmittance experienced by the interference filters; (2) the results of retesting of the thermopile sensors, which appear to be relatively unaffected by the exposure; and (3) the results of the recalibration of the APEX cavity radiometer. The degradation and recovery of the filters of the Nimbus 7 ERB are also discussed relative to the apparent atomic oxygen cleaning which also applies to the LDEF.

  9. Hydrograph Asymmetry Drives Bedload Transport Hysteresis: Evidence from Fluvial Seismology

    NASA Astrophysics Data System (ADS)

    Finnegan, N. J.; Roth, D. L.; Brodsky, E. E.; Hsu, L.

    2015-12-01

    Bedload transport rates are frequently different for an equivalent stage or discharge on the rising and falling limbs of a hydrograph. This asymmetry in transport results in hysteresis in sediment rating curves, which although widely documented, is not well understood mechanistically. A major factor contributing to the uncertain origins of hysteresis is the difficulty associated with making continuous bedload transport measurements in large rivers during floods. However, recent work demonstrates that seismic signals from rivers can provide quantitative constraints on the evolution of bedload transport during storms on large rivers, when direct measurements would otherwise be impossible. Here, we analyze patterns in the amplitude of seismic shaking along the Cho-Shui River in Taiwan and along the Erlenbach Stream in Switzerland during a total of 10 storm events. The storms exhibit varying amounts of hysteresis in the amplitude of seismic shaking as a function of flood discharge (as measured from nearby gages). However, the amount of hysteresis, which we quantify with a non-dimensional metric, correlates strongly with the degree of asymmetry in the flood hydrograph. Specifically, the degree of hysteresis observed during an event scales inversely with the ratio of the rising limb time to the recessional limb time. Flume experiments and field observations indicate that vertical sorting and, hence, armor formation in gravel-bedded river channels is more pronounced during longer storms. Although we lack direct constraints on the bed surface during the observed events, our results support the possibility that differential gravel sorting on the rising and falling limbs is responsible for the observed hysteresis. Specifically, our results imply that for a given stage, armor will be better developed on a slow recessional limb, resulting in lower gravel transport rates and a pattern of clockwise hysteresis.

  10. The mini-earth and the results of pre-habitation experiments

    NASA Astrophysics Data System (ADS)

    Nitta, K.

    The history of construction of CEEF(Mini-Earth), the configuration and scale of CEEF are initially described. The effective areas in plant cultivation and animal breeding and habitation modules and the accommodations equipments installed in each modules are also explained. Mechanism of the material circulation systems belonging to each module and subsystems in each material circulation system are introduced. Finally the results of pre-habitation experiments conducted in Fy.2003 for clarifying the requirements in order to promote final closed habitation experiments are shown.

  11. The Mini-Earth facility and present status of habitation experiment program

    NASA Astrophysics Data System (ADS)

    Nitta, Keiji

    The history of construction of the CEEF (the Mini-Earth), the configuration and scale of the CEEF are initially described. The effective usable areas in plant cultivation and animal holding and habitation modules and the accommodation equipments installed in each module are also explained. Mechanisms of the material circulation systems belonging to each module and subsystems in each material circulation system are introduced. Finally the results of pre-habitation experiments conducted until the year 2004 for clarifying the requirements in order to promote final closed habitation experiments are shown.

  12. Earth's core-mantle boundary - Results of experiments at high pressures and temperatures

    NASA Technical Reports Server (NTRS)

    Knittle, Elise; Jeanloz, Raymond

    1991-01-01

    Laboratory experiments document that liquid iron reacts chemically with silicates at high pressures (above 2.4 x 10 to the 10th Pa) and temperatures. In particular, (Mg,Fe)SiO3 perovskite, the most abundant mineral of earth's lower mantle, is expected to react with liquid iron to produce metallic alloys (FeO and FeSi) and nonmetallic silicates (SiO2 stishovite and MgSiO3 perovskite) at the pressures of the core-mantle boundary, 14 x 10 to the 10th Pa. The experimental observations, in conjunction with seismological data, suggest that the lowermost 200 to 300 km of earth's mantle, the D-double-prime layer, may be an extremely heterogeneous region as a result of chemical reactions between the silicate mantle and the liquid iron alloy of earth's core. The combined thermal-chemical-electrical boundary layer resulting from such reactions offers a plausible explanation for the complex behavior of seismic waves near the core-mantle boundary and could influence earth's magnetic field observed at the surface.

  13. Earth's core-mantle boundary - Results of experiments at high pressures and temperatures

    NASA Technical Reports Server (NTRS)

    Knittle, Elise; Jeanloz, Raymond

    1991-01-01

    Laboratory experiments document that liquid iron reacts chemically with silicates at high pressures (above 2.4 x 10 to the 10th Pa) and temperatures. In particular, (Mg,Fe)SiO3 perovskite, the most abundant mineral of earth's lower mantle, is expected to react with liquid iron to produce metallic alloys (FeO and FeSi) and nonmetallic silicates (SiO2 stishovite and MgSiO3 perovskite) at the pressures of the core-mantle boundary, 14 x 10 to the 10th Pa. The experimental observations, in conjunction with seismological data, suggest that the lowermost 200 to 300 km of earth's mantle, the D-double-prime layer, may be an extremely heterogeneous region as a result of chemical reactions between the silicate mantle and the liquid iron alloy of earth's core. The combined thermal-chemical-electrical boundary layer resulting from such reactions offers a plausible explanation for the complex behavior of seismic waves near the core-mantle boundary and could influence earth's magnetic field observed at the surface.

  14. Earth's Core-Mantle Boundary: Results of Experiments at High Pressures and Temperatures.

    PubMed

    Knittle, E; Jeanloz, R

    1991-03-22

    Laboratory experiments document that liquid iron reacts chemically with silicates at high pressures (>/=2.4 x 10(10) Pascals) and temperatures. In particular, (Mg,Fe)SiO(3) perovskite, the most abundant mineral of Earth's lower mantle, is expected to react with liquid iron to produce metallic alloys (FeO and FeSi) and nonmetallic silicates (SiO(2) stishovite and MgSiO(3) perovskite) at the pressures of the core-mantle boundary, 14 x 10(10) Pascals. The experimental observations, in conjunction with seismological data, suggest that the lowermost 200 to 300 kilometers of Earth's mantle, the D" layer, may be an extremely heterogeneous region as a result of chemical reactions between the silicate mantle and the liquid iron alloy of Earth's core. The combined thermal-chemical-electrical boundary layer resulting from such reactions offers a plausible explanation for the complex behavior of seismic waves near the core-mantle boundary and could influence Earth's magnetic field observed at the surface.

  15. An Experiment for Simulated Detection of Earth-Size Planetary Transits

    NASA Astrophysics Data System (ADS)

    Koch, D.; Borucki, W.; Dunham, E.; Jenkins, J.; Witteborn, F.

    1999-05-01

    The concept for detection of Earth-size planets by looking for transits has been described by Borucki and Summers (1984). A space mission for detecting hundreds of Earth-size planets has been described by Koch, et al. (1998). The method depends on reliably detecting a relative change in brightness of order 8x10(-5) . Prior laboratory measurements have demonstrated this level of relative precision using CCDs (Robinson, et al., 1995, Jenkins, et al., 1997). A higher fidelity experiment is now being constructed to detect simulated Earth-size transits using a flight-type CCD. In addition, the experiment incorporates many of the major confounding factors which could affect the detection capability including: spacecraft jitter, a realistic star background, thermal changes, stellar variability, cosmic-ray hits, etc. Details of the experiment are presented including the method for producing the equivalent of earth-size transit signals. Borucki, W. J. and Summers, A.L., Icarus 58, 121 (1984) Jenkins, J. M., Borucki, W. J., Dunham, E. W. and McDonald, J. S., High Precision Photometry with Back-Illuminated CCDs, In Proceedings of the Planets Beyond Our Solar System and Next Generation Space Telescope, ASP Conf Ser ,119, 227-280 (1997) Koch, D., Borucki, W., Webster, L., Dunham, E. , Jenkins, J., Marriott, J. and Reitsema, H., SPIE 3356, Space Telescopes and Instruments V, 599-607, March (1998) Robinson, L. B, M. Z. Wei, W. J. Borucki, E.W. Dunham, C. H. Ford, and A. F. Granados. PASP 107, 1094-1098 (1995)

  16. An investigation of ESSA 7 radiation data for use in long-term earth energy experiments, phases 1 and 2

    NASA Technical Reports Server (NTRS)

    House, F. B.

    1974-01-01

    The results are presented of an investigation of ESSA 7 satellite radiation data for use in long-term earth energy experiments. Satellite systems for performing long-term earth radiation balance measurements over geographical areas, hemispheres, and the entire earth for periods of 10 to 30 years are examined. The ESSA 7 satellite employed plate and cone radiometers to measure earth albedo and emitted radiation. Each instrument had a black and white radiometer which discriminated the components of albedo and emitted radiation. Earth measurements were made continuously from ESSA 7 for ten months. The ESSA 7 raw data is processed to a point where it can be further analyzed for: (1) development of long-term earth energy experiments; and (2) document climate trends.

  17. Ocean and atmosphere feedbacks affecting AMOC hysteresis in a GCM

    NASA Astrophysics Data System (ADS)

    Jackson, L. C.; Smith, R. S.; Wood, R. A.

    2016-10-01

    Theories suggest that the Atlantic Meridional Overturning Circulation (AMOC) can exhibit a hysteresis where, for a given input of fresh water into the north Atlantic, there are two possible states: one with a strong overturning in the north Atlantic (on) and the other with a reverse Atlantic cell (off). A previous study showed hysteresis of the AMOC for the first time in a coupled general circulation model (Hawkins et al. in Geophys Res Lett. doi: 10.1029/2011GL047208, 2011). In this study we show that the hysteresis found by Hawkins et al. (2011) is sensitive to the method with which the fresh water input is compensated. If this compensation is applied throughout the volume of the global ocean, rather than at the surface, the region of hysteresis is narrower and the off states are very different: when the compensation is applied at the surface, a strong Pacific overturning cell and a strong Atlantic reverse cell develops; when the compensation is applied throughout the volume there is little change in the Pacific and only a weak Atlantic reverse cell develops. We investigate the mechanisms behind the transitions between the on and off states in the two experiments, and find that the difference in hysteresis is due to the different off states. We find that the development of the Pacific overturning cell results in greater atmospheric moisture transport into the North Atlantic, and also is likely responsible for a stronger Atlantic reverse cell. These both act to stabilize the off state of the Atlantic overturning.

  18. Ocean and atmosphere feedbacks affecting AMOC hysteresis in a GCM

    NASA Astrophysics Data System (ADS)

    Jackson, L. C.; Smith, R. S.; Wood, R. A.

    2017-07-01

    Theories suggest that the Atlantic Meridional Overturning Circulation (AMOC) can exhibit a hysteresis where, for a given input of fresh water into the north Atlantic, there are two possible states: one with a strong overturning in the north Atlantic (on) and the other with a reverse Atlantic cell (off). A previous study showed hysteresis of the AMOC for the first time in a coupled general circulation model (Hawkins et al. in Geophys Res Lett. doi: 10.1029/2011GL047208, 2011). In this study we show that the hysteresis found by Hawkins et al. (2011) is sensitive to the method with which the fresh water input is compensated. If this compensation is applied throughout the volume of the global ocean, rather than at the surface, the region of hysteresis is narrower and the off states are very different: when the compensation is applied at the surface, a strong Pacific overturning cell and a strong Atlantic reverse cell develops; when the compensation is applied throughout the volume there is little change in the Pacific and only a weak Atlantic reverse cell develops. We investigate the mechanisms behind the transitions between the on and off states in the two experiments, and find that the difference in hysteresis is due to the different off states. We find that the development of the Pacific overturning cell results in greater atmospheric moisture transport into the North Atlantic, and also is likely responsible for a stronger Atlantic reverse cell. These both act to stabilize the off state of the Atlantic overturning.

  19. Hysteresis and the Dynamic Elasticity of Consolidated Granular Materials

    SciTech Connect

    Guyer, R.A.; TenCate, J.; Johnson, P.

    1999-04-01

    Quasistatic elasticity measurements on rocks show them to be strikingly nonlinear and to have elastic hysteresis with end point memory. When the model for this quasistatic elasticity is extended to the description of nonlinear dynamic elasticity the elastic elements responsible for the hysteresis dominate the behavior. Consequently, in a resonant bar, driven to nonlinearity, the frequency shift and the attenuation are predicted to be nonanalytic functions of the strain field. A resonant bar experiment yielding results in substantial qualitative and quantitative accord with these predictions is reported. {copyright} {ital 1999} {ital The American Physical Society }

  20. Hysteresis of boiling for different tunnel-pore surfaces

    NASA Astrophysics Data System (ADS)

    Pastuszko, Robert; Piasecka, Magdalena

    2015-05-01

    Analysis of boiling hysteresis on structured surfaces covered with perforated foil is proposed. Hysteresis is an adverse phenomenon, preventing high heat flux systems from thermal stabilization, characterized by a boiling curve variation at an increase and decrease of heat flux density. Experimental data were discussed for three kinds of enhanced surfaces: tunnel structures (TS), narrow tunnel structures (NTS) and mini-fins covered with the copper wire net (NTS-L). The experiments were carried out with water, R-123 and FC-72 at atmospheric pressure. A detailed analysis of the measurement results identified several cases of type I, II and III for TS, NTS and NTS-L surfaces.

  1. Conditions necessary for capillary hysteresis in porous media: Tests of grain size and surface tension influences

    NASA Astrophysics Data System (ADS)

    Tokunaga, Tetsu K.; Olson, Keith R.; Wan, Jiamin

    2004-05-01

    Hysteresis in the relation between water saturation and matric potential is generally regarded as a basic aspect of unsaturated porous media. However, the nature of an upper length scale limit for saturation hysteresis has not been previously addressed. Since hysteresis depends on whether or not capillary rise occurs at the grain scale, this criterion was used to predict required combinations of grain size, surface tension, fluid-fluid density differences, and acceleration in monodisperse systems. The Haines number (Ha), composed of the aforementioned variables, is proposed as a dimensionless number useful for separating hysteretic (Ha < 15) versus nonhysteretic (Ha > 15) behavior. Vanishing of hysteresis was predicted to occur for grain sizes greater than 10.4 ± 0.5 mm, for water-air systems under the acceleration of ordinary gravity, based on Miller-Miller scaling and Haines' original model for hysteresis. Disappearance of hysteresis was tested through measurements of drainage and wetting curves of sands and gravels and occurs between grain sizes of 10 and 14 mm (standard conditions). The influence of surface tension was tested through measurements of moisture retention in 7 mm gravel, without and with a surfactant (sodium dodecylbenzenesulfonate (SDBS)). The ordinary water system (Ha = 7) exhibited hysteresis, while the SDBS system (Ha = 18) did not. The experiments completed in this study indicate that hysteresis in moisture retention relations has an upper limit at Ha = 16 ± 2 and show that hysteresis is not a fundamental feature of unsaturated porous media.

  2. Intercomparison of scanner and nonscanner measurements for the Earth Radiation Budget Experiment

    NASA Technical Reports Server (NTRS)

    Green, Richard N.; House, Frederick B.; Stackhouse, Paul W.; Wu, Xiangqian; Ackerman, Steven A.

    1990-01-01

    The Earth Radiation Budget Experiment nonscanner measurements are simulated with the scanner measurements. The error in simulating a single measurement is 1 percent for longwave and 3 percent for shortwave. Errors in simulating the average daily measurements are half these amounts. Four months of Earth Radiation Budget Satellite measurements were analyzed. The results show that changing sun geometry affects the accuracy of the nonscanner measurements. The medium field show that changing sun geometry affects the accuracy of the nonscanner measurements. The medium field of view (MFOV) total channel and scanner agree to within 2 percent on average. The wide field of view (WFOV) total channel and scanner agree to within 1 percent. For the shortwave channels, the agreement with the scanner is 2 percent for the MFOV and 2.5 percent for the WFOV.

  3. Challenges and Opportunities for Developing Capacity in Earth Observations for Agricultural Monitoring: The GEOGLAM Experience

    NASA Astrophysics Data System (ADS)

    Whitcraft, A. K.; Di Bella, C. M.; Becker Reshef, I.; Deshayes, M.; Justice, C. O.

    2015-12-01

    Since 2011, the Group on Earth Observations Global Agricultural Monitoring (GEOGLAM) Initiative has been working to strengthen the international community's capacity to use Earth observation (EO) data to derive timely, accurate, and transparent information on agriculture, with the goals of reducing market volatility and promoting food security. GEOGLAM aims to develop capacity for EO-based agricultural monitoring at multiple scales, from national to regional to global. This is accomplished through training workshops, developing and transferring of best-practices, establishing networks of broad and sustainable institutional support, and designing or adapting tools and methodologies to fit localized contexts. Over the past four years, capacity development activities in the context of GEOGLAM have spanned all agriculture-containing continents, with much more work to be done, particularly in the domains of promoting access to large, computationally-costly datasets. This talk will detail GEOGLAM's experiences, challenges, and opportunities surrounding building international collaboration, ensuring institutional buy-in, and developing sustainable programs.

  4. Summary of flight performance of the Skylab Earth Resources Experiment Package /EREP/

    NASA Technical Reports Server (NTRS)

    Potter, A. E.; Williams, C. K.; Grandfield, A. L.; Demel, K. J.; Trichel, M. C.; Barnett, T. L.; Juday, R. D.; Hensley, W. E.; Hatcher, N. M.; Mcallum, W. E.

    1974-01-01

    A group of six remote sensor systems (sensing visible, infrared, and microwave radiation) known as the Earth Resources Experiment Package (EREP) was flown on the NASA Skylab spacecraft to furnish data to numerous investigators in the earth sciences and in technology assessment. Inflight sensor performance in three categories (functional, geometric, and radiometric) was evaluated using: (1) ground measurements of surface, atmospheric, and illumination parameters; (2) ground deployment and operation of microwave receivers and transponders to monitor and excite the active EREP sensors; (3) measurement of surface and atmospheric parameters by instrumented aircraft on underflights of Skylab passes; and (4) analysis of the actual flight data. This resulted in identification and correction of anomalous sensor operation, quantization of geometric distortions or aberrations, improvement or confirmation of calibrations, and determination of sensitivity, accuracy, and stability of the sensors.

  5. Seasonal variation of cloud radiative forcing derived from the Earth Radiation Budget Experiment

    NASA Technical Reports Server (NTRS)

    Harrison, E. F.; Minnis, P.; Barkstrom, B. R.; Ramanathan, V.; Cess, R. D.

    1990-01-01

    The impact of clouds on the earth's radiation balance is assessed in terms of longwave, shortwave, and net cloud forcing by using monthly averaged clear-sky and cloudy-sky flux data derived from the NASA Earth Radiation Budget Experiment (ERBE). Emphasis is placed on regional measurements, regional cloud forcing, zonal cloud forcing, and snow and ice contributions. It is shown that the global mean cooling varied from 14 to 21 W/sq m between April 1985 and January 1986; hemispherically, the longwave and shortwave cloud forcing nearly cancel each other in the winter hemisphere, while in the summer the negative shortwave cloud forcing is significantly lower than the longwave cloud forcing, producing a strong cooling. The ERBE data reveal that globally, hemispherically, and zonally, clouds have a significant effect on the radiative heating gradients.

  6. Energetic model of ferromagnetic hysteresis

    NASA Astrophysics Data System (ADS)

    Hauser, Hans

    1994-03-01

    Calculations of a total energy function are used to describe a theory of hysteresis effects in crystalline, ferromagnetic materials. This model is applied on the cubic structure of FeSi crystals, which are oriented in a (110)[001] texture. The magnetic energy of the crystal is separated in reversible and irreversible parts: The reversible energy is expressed by magnetocrystalline anisotropy and shape anisotropy. They are responsible for the rotation of the domain magnetization at strong fields. At weak fields the reversible interaction of the domain wall motion with the stray fields of pinning centers (nonmagnetic inclusions, grain boundaries or inner strains) is described by a probability function of statistic domain behavior. The irreversible energy is caused by these pinning centers, too, and can be explained by the interaction losses of the magnetic moments in the Bloch wall with the crystal lattice during an irreversible Barkhausen jump. The energy of the applied field is added to these two parts and the magnetic state of the material is represented by the minima of the total energy function. The results show all features of hysteresis such as initial magnetization curve and major and minor hysteresis loops in good agreement with measurements on grain oriented 3,5% silicon-steel with Goss texture.

  7. Efficient Computational Model of Hysteresis

    NASA Technical Reports Server (NTRS)

    Shields, Joel

    2005-01-01

    A recently developed mathematical model of the output (displacement) versus the input (applied voltage) of a piezoelectric transducer accounts for hysteresis. For the sake of computational speed, the model is kept simple by neglecting the dynamic behavior of the transducer. Hence, the model applies to static and quasistatic displacements only. A piezoelectric transducer of the type to which the model applies is used as an actuator in a computer-based control system to effect fine position adjustments. Because the response time of the rest of such a system is usually much greater than that of a piezoelectric transducer, the model remains an acceptably close approximation for the purpose of control computations, even though the dynamics are neglected. The model (see Figure 1) represents an electrically parallel, mechanically series combination of backlash elements, each having a unique deadband width and output gain. The zeroth element in the parallel combination has zero deadband width and, hence, represents a linear component of the input/output relationship. The other elements, which have nonzero deadband widths, are used to model the nonlinear components of the hysteresis loop. The deadband widths and output gains of the elements are computed from experimental displacement-versus-voltage data. The hysteresis curve calculated by use of this model is piecewise linear beyond deadband limits.

  8. Earthdata 3.0: A Unified Experience and Platform for Earth Science Discovery

    NASA Astrophysics Data System (ADS)

    Plofchan, P.; McLaughlin, B. D.

    2015-12-01

    NASA's EOSDIS (Earth Observing System Data and Information System) as a multitude of websites and applications focused on serving the Earth Science community's extensive data needs. With no central user interface, theme, or mechanism for accessing that data, interrelated systems are confusing and potentially disruptive in users' searches for EOSDIS data holdings. In an effort to bring consistency across these systems, an effort was undertaken to develop Earthdata 3.0: a complete information architecture overhaul of the Earthdata website, a significant update to the Earthdata user experience and user interface, and an increased focus on searching across EOSDIS data holdings, including those housed and made available through DAAC websites. As part of this effort, and in a desire to unify the user experience across related websites, the Earthdata User Interface (EUI) was developed. The EUI is a collection of responsive design components and layouts geared toward creating websites and applications within the Earthdata ecosystem. Each component and layout has been designed specifically for Earth science-related projects which eliminates some of the complexities of building a website or application from the ground up. Its adoption will ensure both consistent markup and a unified look and feel for end users, thereby increasing usability and accessibility. Additionally, through the user of a Google Search Appliance, custom Clojure code, and in cooperation with DAACs, Earthdata 3.0 presents a variety of search results upon a user's keyword(s) entry. These results are not just textual links, but also direct links to downloadable datasets, visualizations of datasets and collections of data, and related articles and videos for further research. The end result of the development of the EUI and the enhanced multi-response type search is a consistent and usable platform for Earth scientists and users to navigate and locate data to further their research.

  9. Determining Appropriate Coupling between User Experiences and Earth Science Data Services

    NASA Astrophysics Data System (ADS)

    Moghaddam-Taaheri, E.; Pilone, D.; Newman, D. J.; Mitchell, A. E.; Goff, T. D.; Baynes, K.

    2012-12-01

    NASA's Earth Observing System ClearingHOuse (ECHO) is a format agnostic metadata repository supporting over 3000 collections and 100M granules. ECHO exposes FTP and RESTful Data Ingest APIs in addition to both SOAP and RESTful search and order capabilities. Built on top of ECHO is a human facing search and order web application named Reverb. Reverb exposes ECHO's capabilities through an interactive, Web 2.0 application designed around searching for Earth Science data and downloading or ordering data of interest. ECHO and Reverb have supported the concept of Earth Science data services for several years but only for discovery. Invocation of these services was not a primary capability of the user experience. As more and more Earth Science data moves online and away from the concept of data ordering, progress has been made in making on demand services available for directly accessed data. These concepts have existed through access mechanisms such as OPeNDAP but are proliferating to accommodate a wider variety of services and service providers. Recently, the EOSDIS Service Interface (ESI) was defined and integrated into the ECS system. The ESI allows data providers to expose a wide variety of service capabilities including reprojection, reformatting, spatial and band subsetting, and resampling. ECHO and Reverb were tasked with making these services available to end-users in a meaningful and usable way that integrated into its existing search and ordering workflow. This presentation discusses the challenges associated with exposing disparate service capabilities while presenting a meaningful and cohesive user experience. Specifically, we'll discuss: - Benefits and challenges of tightly coupling the user interface with underlying services - Approaches to generic service descriptions - Approaches to dynamic user interfaces that better describe service capabilities while minimizing application coupling - Challenges associated with traditional WSDL / UDDI style service

  10. Implications for Core Formation of the Earth from High Pressure-Temperature Au Partitioning Experiments

    NASA Technical Reports Server (NTRS)

    Danielson, L. R.; Sharp, T. G.; Hervig, R. L.

    2005-01-01

    Siderophile elements in the Earth.s mantle are depleted relative to chondrites. This is most pronounced for the highly siderophile elements (HSEs), which are approximately 400x lower than chondrites. Also remarkable is the relative chondritic abundances of the HSEs. This signature has been interpreted as representing their sequestration into an iron-rich core during the separation of metal from silicate liquids early in the Earth's history, followed by a late addition of chondritic material. Alternative efforts to explain this trace element signature have centered on element partitioning experiments at varying pressures, temperatures, and compositions (P-T-X). However, first results from experiments conducted at 1 bar did not match the observed mantle abundances, which motivated the model described above, a "late veneer" of chondritic material deposited on the earth and mixed into the upper mantle. Alternatively, the mantle trace element signature could be the result of equilibrium partitioning between metal and silicate in the deep mantle, under P-T-X conditions which are not yet completely identified. An earlier model determined that equilibrium between metal and silicate liquids could occur at a depth of approximately 700 km, 27(plus or minus 6) GPa and approximately 2000 (plus or minus 200) C, based on an extrapolation of partitioning data for a variety of moderately siderophile elements obtained at lower pressures and temperatures. Based on Ni-Co partitioning, the magma ocean may have been as deep as 1450 km. At present, only a small range of possible P-T-X trace element partitioning conditions has been explored, necessitating large extrapolations from experimental to mantle conditions for tests of equilibrium models. Our primary objective was to reduce or remove the additional uncertainty introduced by extrapolation by testing the equilibrium core formation hypothesis at P-T-X conditions appropriate to the mantle.

  11. Technology and science from Earth to Moon: SMART-1 experiments and their operations

    NASA Astrophysics Data System (ADS)

    Marini, A. E.; Lumb, R.; Racca, G. D.; Foing, B. H.; Dias-Almeida, M.

    2002-10-01

    SMART-1, the first European mission to the Moon aimed at demonstrating the Solar Electric propulsion hosts 10 Technology and Science experiments. The monitoring of the spacecraft plasma environment and the thruster contamination produced by thruster is carried out by SPEDE (Spacecraft Potential, Electron and Dust Experiment) and EPDP (Electric Propulsion Diagnostic Package). The miniaturised remote sensing instruments on-board SMART-1 are: AMIE (Advanced Moon micro-Imager Experiment), D-CIXS (Demonstration of a Compact Imaging X-ray Spectrometer), supported in its operation by XSM (X-ray Solar Monitor), and SIR (SMART-1 Infrared Spectrometer). Technology experiments for deep-space communications and navigation are: KATE (Ka-Band TT&C Experiment), based on X/Kaband transponder which also supports RSIS (Radio-Science Investigations for SMART-1), Laser-link, demonstrating a deep-space laser communication link and OBAN (On-Board Autonomous Navigation experiment). The Experiments will be performed during two distinct phases of the SMART-1 mission, including 17-month Earth escape phase and a nominal 6-month operational phase in elliptical Moon orbit. The SMART-1 STOC (Science and Technology Operations Co-ordination) carries out the planning and co-ordination of the Technology and science experiments.

  12. Statistical analysis of Contact Angle Hysteresis

    NASA Astrophysics Data System (ADS)

    Janardan, Nachiketa; Panchagnula, Mahesh

    2015-11-01

    We present the results of a new statistical approach to determining Contact Angle Hysteresis (CAH) by studying the nature of the triple line. A statistical distribution of local contact angles on a random three-dimensional drop is used as the basis for this approach. Drops with randomly shaped triple lines but of fixed volumes were deposited on a substrate and their triple line shapes were extracted by imaging. Using a solution developed by Prabhala et al. (Langmuir, 2010), the complete three dimensional shape of the sessile drop was generated. A distribution of the local contact angles for several such drops but of the same liquid-substrate pairs is generated. This distribution is a result of several microscopic advancing and receding processes along the triple line. This distribution is used to yield an approximation of the CAH associated with the substrate. This is then compared with measurements of CAH by means of a liquid infusion-withdrawal experiment. Static measurements are shown to be sufficient to measure quasistatic contact angle hysteresis of a substrate. The approach also points towards the relationship between microscopic triple line contortions and CAH.

  13. Comparison of the measured and predicted response of the Earth Radiation Budget Experiment active cavity radiometer during solar observations.

    PubMed

    Mahan, J R; Tira, N E; Lee Iii, R B; Keynton, R J

    1989-04-01

    The Earth Radiation Budget Experiment consists of an array of radiometric instruments placed in earth orbit by the National Aeronautics and Space Administration to monitor the longwave and visible components of the earth's radiation budget. Presented is a dynamic electrothermal model of the active cavity radiometer used to measure the earth's total radiative exitance. Radiative exchange is modeled using the Monte Carlo method and transient conduction is treated using the finite element method. Also included is the feedback circuit which controls electrical substitution heating of the cavity. The model is shown to accurately predict the dynamic response of the instrument during solar calibration.

  14. A Study on Earth Re-entry Capsules with Deployable Aerobrakes for Recoverable Microgravity Experiments

    NASA Astrophysics Data System (ADS)

    Carandente, Valerio; Savino, Raffaele; D'Oriano, Vera; Fortezza, Raimondo

    2015-06-01

    Deployable aerobrakes for Earth re-entry capsules may offer many advantages in the near future, including the opportunity to recover on Earth scientific payloads from the Space with reduced risks and costs with respect to conventional systems. Such capsules can be accommodated in the selected launcher in folded configuration optimizing the available volume and, when planned by the mission profile, the aerobrake can be deployed in order to increase the surface exposed to the hypersonic flow and therefore to reduce the ballistic parameter. This can offer as main advantage the opportunity to perform an aerodynamic de-orbit of the system without the need of a dedicated propulsive subsystem and an atmospheric re-entry with reduced aerothermal and mechanical loads making possible the use of relatively lightweight and cheap thermal protection system materials. To ensure the recovery of the capsule, the deployable surface can be modulated to obtain the aerodynamic control of the de-orbit trajectory in order to correctly target the capsule towards the selected landing site for post-flight analyses and operations. The main objective of the work is to present a number of feasible mission profiles for orbital platforms to/from Low Earth Orbit aimed in particular at scientific experiments in microgravity conditions. In addition, a suborbital scenario for a technological demonstrator, useful to experimentally verify the system applicability before the design of orbital missions, is also presented and discussed.

  15. Mobile Bay, Alabama area seen in Skylab 4 Earth Resources Experiment Package

    NASA Technical Reports Server (NTRS)

    1974-01-01

    A near vertical view of the Mobile Bay, Alabama area seen in this Skylab 4 Earth Resources Experiment Package S190-B (five-inch earth terrain camera) photograph taken from the Skylab space station in earth orbit. North of Mobile the Tombigbee and Alabama Rivers join to form the Mobile River. Detailed configuration of the individual stream channels and boundaries can be defined as the Mobile River flows into Mobile Bay and into the Gulf of Mexico. The Mobile River Valley with its numerous stream channels is a distinct light shade in contrast to the dark green shade of the adjacent areas. The red coloration of Mobile Bay reflects the sediment load carried into the bay by the rivers. The westerly movement of the shore currents at the mouth of Mobile Bay is shown by the contrasting light blue of the sediment-laden current the the blue of the Gulf. Agricultural areas east and west of Mobile Bay are characterized by a rectangular pattern in green to white shades. Color variations may reflect

  16. Hysteresis and Kinetic Effects During Liquid-Solid Transitions

    SciTech Connect

    Streitz, F H; Chau, R

    2009-02-17

    We address the fundamental issue of phase transition kinetics in dynamically compressed materials. Focusing on solid bismuth (Bi) as a prototype material, we used a variety of time-resolved experiments including electrical conductivity and velocimetry to study the phase transition kinetics of the solid-solid phase transitions. Simple single shock experiments performed on several low-lying high pressure phases of Bi, revealed surprisingly complex behavior and slow dynamics. Strong hysteresis effects were observed in the transition behavior in experiments where the compressed Bi was allowed to release back across a phase line. These experiments represent the first reported simultaneous use of resistivity and velocimetry in a shock compression experiment, and the first observation of hysteresis effects occurring during dynamic compression and release.

  17. Mobile Bay, Alabama area seen in Skylab 4 Earth Resources Experiment Package

    NASA Image and Video Library

    1974-02-01

    SL4-92-300 (February 1974) --- A near vertical view of the Mobile Bay, Alabama area is seen in this Skylab 4 Earth Resources Experiments Package S190-B (five-inch earth terrain camera) photograph taken from the Skylab space station in Earth orbit. North of Mobile the Tombigbee and Alabama Rivers join to form the Mobile River. Detailed configuration of the individual stream channels and boundaries can be defined as the Mobile River flows into Mobile Bay, and thence into the Gulf of Mexico. The Mobile River Valley with its numerous stream channels is a distinct light shade in contrast to the dark green shade of the adjacent areas. The red coloration of Mobile Bay reflects the sediment load carried into the Bay by the rivers. Variations in red color indicate sediment load and the current paths within Mobile Bay. The waterly movement of the along shore currents at the mouth of Mobile Bay is shown by the contrasting light blue of the sediment-laden current and the blue of the Gulf predominately. Agricultural areas east and west of Mobile Bay are characterized by a rectangular pattern in green to white shades. Color variations may reflect the type and growth cycle of crops. Agricultural areas (light gray-greens) are also clearly visible in other parts of the photograph. Interstate 10 extends from near Pascagoula, Mississippi eastward through Mobile to the outskirts of Pensacola, Florida. Analysis of the EREP photographic data will be undertaken by the U.S. Corps of Engineers to determine bay dynamic processes. Federal agencies participating with NASA on the EREP project are the Departments of Agriculture, Commerce, Interior, the Environmental Protection Agency and the Corps of Engineers. All EREP photography is available to the public through the Department of Interior's Earth Resources Observations Systems Data Center, Sioux Falls, South Dakota. 57198 Photo credit: NASA

  18. Consistency of Earth Radiation Budget Experiment bidirectional models and the observed anisotropy of reflected sunlight

    SciTech Connect

    Baldwin, D.G. ); Coakley, J.A. )

    1991-03-20

    The Earth Radiation Budget Experiment (ERBE) uses bidirectional models to estimate radiative fluxes from observed radiances. The anisotropy of the radiance field derived from these models is compared with that observed with the ERBE scanner on the Earth Radiation Budget Satellite (ERBS). The bidirectional models used by ERBE were derived from NIMBUS 7 Earth radiation budget (ERB) scanner observations. Because of probable differences in the radiometric calibrations of the ERB and ERBE scanners and because of differences in their field of view sizes, the authors expect to find systematic differences of a few percent between the NIMBUS 7 ERB-derived radiation field anisotropy and the ERBS scanner-observed anisotropy. The differences expected are small compared with the variability of the anisotropy which arises from the variability in cloud cover allowed to occur within the individual scene types. By averaging over groups of 40 ERBE scanner scan lines (equivalent to an average over approximately 2,000 km) for a period of a month, they detect significant differences between the modeled and observed anisotropy for particular scene types and Sun-Earth-satellite viewing geometries. For a typical 2.5{degree} latitude-longitude region these differences give rise to a bias in the radiative flux that is at least 0.3% for the monthly mean and an rms error that is at least 4% for instantaneous observations. By comparing the fluxes derived using the observed anisotropy with those derived assuming isotropic reflection, they conclude that a reasonable estimate for the maximum error due to the use of incorrect bidirectional models is a bias of approximately 4% for a typical 2.5{degree} latitude-longitude, monthly mean and an rms error of 15%.

  19. VIIRS day-night band (DNB) electronic hysteresis: characterization and correction

    NASA Astrophysics Data System (ADS)

    Mills, Stephen

    2016-09-01

    The VIIRS Day-Night Band (DNB) offers measurements over a dynamic range from full daylight to the dimmest nighttime. This makes radiometric calibration difficult because effects that are otherwise negligible become significant for the DNB. One of these effects is electronic hysteresis and this paper evaluates this effect and its impact on calibration. It also considers possible correction algorithms. The cause of this hysteresis is uncertain, but since the DNB uses a charge-coupled device (CCD) detector array, it is likely the result of residual charge or charge depletion. The effects of hysteresis are evident in DNB imagery. Steaks are visible in the cross-track direction around very bright objects such as gas flares. Dark streaks are also visible after lightning flashes. Each VIIRS scan is a sequence of 4 sectors: space view (SV); Earth-view (EV); blackbody (BB) view; and solar diffuser (SD) view. There are differences among these sectors in offset that can only be explained as being the result of hysteresis from one sector to the next. The most dramatic hysteresis effect is when the sun illuminates the SD and hysteresis is then observed in the SV and EV. Previously this was hypothesized to be due to stray light leaking from the SD chamber, but more careful evaluation shows that this can only be the result of hysteresis. There is a stray light correction algorithm that treats this as stray light, but there are problems with this that could be remedied by instead using the characterization presented here.

  20. Stabilizing the earth's climate is not a losing game: supporting evidence from public goods experiments.

    PubMed

    Milinski, Manfred; Semmann, Dirk; Krambeck, Hans-Jürgen; Marotzke, Jochem

    2006-03-14

    Maintaining the Earth's climate within habitable boundaries is probably the greatest "public goods game" played by humans. However, with >6 billion "players" taking part, the game seems to rule out individual altruistic behavior. Thus, climate protection is a problem of sustaining a public resource that everybody is free to overuse, a "tragedy of the commons" problem that emerges in many social dilemmas. We perform a previously undescribed type of public goods experiment with human subjects contributing to a public pool. In contrast to the standard protocol, here the common pool is not divided among the participants; instead, it is promised that the pool will be invested to encourage people to reduce their fossil fuel use. Our extensive experiments demonstrate that players can behave altruistically to maintain the Earth's climate given the right set of circumstances. We find a nonzero basic level of altruistic behavior, which is enhanced if the players are provided with expert information describing the state of knowledge in climate research. Furthermore, personal investments in climate protection increase substantially if players can invest publicly, thus gaining social reputation. This increase occurs because subjects reward other subjects' contributions to sustaining the climate, thus reinforcing their altruism. Therefore, altruism may convert to net personal benefit and to relaxing the dilemma if the gain in reputation is large enough. Our finding that people reward contributions to sustaining the climate of others is a surprising result. There are obvious ways these unexpected findings can be applied on a large scale.

  1. Comparative Analysis of Thaumatin Crystals Grown on Earth and in Microgravity. Experiment 23

    NASA Technical Reports Server (NTRS)

    Ng, Joseph D.; Lorber, Bernard; Giege, Richard; Koszelak, Stanley; Day, John; Greenwood, Aaron; McPherson, Alexander

    1998-01-01

    The protein thaumatin was studied as a model macromolecule for crystallization in microgravity environment experiments conducted on two U.S. Space Shuttle missions (second United States Microgravity Laboratory (USML-2) and Life and Microgravity Spacelab (LMS)). In this investigation we evaluated and compared the quality of space- and Earth-grown thaumatin crystals using x-ray diffraction analysis and characterized them according to crystal size, diffraction resolution limit, and mosaicity. Two different approaches for growing thaumatin crystals in the microgravity environment, dialysis and liquid-liquid diffusion, were employed as a joint experiment by our two investigative teams. Thaumatin crystals grown under a microgravity environment were generally larger in volume with fewer total crystals. They diffracted to significantly higher resolution and with improved diffraction properties as judged by relative Wilson plots. The mosaicity for space-grown crystals was significantly less than for those grown on Earth. Increasing concentrations of protein in the crystallization chambers under microgravity lead to larger crystals. The data presented here lend further support to the idea that protein crystals of improved quality can be obtained in a microgravity environment.

  2. Refurbishment of the cryogenic coolers for the Skylab earth resources experiment package

    NASA Technical Reports Server (NTRS)

    Smithson, J. C.; Luksa, N. C.

    1975-01-01

    Skylab Earth Resources Experiment Package (EREP) experiments, S191 and S192, required a cold temperature reference for operation of a spectrometer. This cold temperature reference was provided by a subminiature Stirling cycle cooler. However, the failure of the cooler to pass the qualification test made it necessary for additional cooler development, refurbishment, and qualification. A description of the failures and the cause of these failures for each of the coolers is presented. The solutions to the various failure modes are discussed along with problems which arose during the refurbishment program. The rationale and results of various tests are presented. The successful completion of the cryogenic cooler refurbishment program resulted in four of these coolers being flown on Skylab. The system operation during the flight is presented.

  3. Contact angle hysteresis on fluoropolymer surfaces.

    PubMed

    Tavana, H; Jehnichen, D; Grundke, K; Hair, M L; Neumann, A W

    2007-10-31

    Contact angle hysteresis of liquids with different molecular and geometrical properties on high quality films of four fluoropolymers was studied. A number of different causes are identified for hysteresis. With n-alkanes as probe liquids, contact angle hysteresis is found to be strongly related to the configuration of polymer chains. The largest hysteresis is obtained with amorphous polymers whereas the smallest hysteresis occurs for polymers with ordered molecular chains. This is explained in terms of sorption of liquid by the solid and penetration of liquid into the polymer film. Correlation of contact angle hysteresis with the size of n-alkane molecules supports this conclusion. On the films of two amorphous fluoropolymers with different molecular configurations, contact angle hysteresis of one and the same liquid with "bulky" molecules is shown to be quite different. On the surfaces of Teflon AF 1600, with stiff molecular chains, the receding angles of the probe liquids are independent of contact time between solid and liquid and similar hysteresis is obtained for all the liquids. Retention of liquid molecules on the solid surface is proposed as the most likely cause of hysteresis in these systems. On the other hand, with EGC-1700 films that consist of flexible chains, the receding angles are strongly time-dependent and the hysteresis is large. Contact angle hysteresis increases even further when liquids with strong dipolar intermolecular forces are used. In this case, major reorganization of EGC-1700 chains due to contact with the test liquids is suggested as the cause. The effect of rate of motion of the three-phase line on the advancing and receding contact angles, and therefore contact angle hysteresis, is investigated. For low viscous liquids, contact angles are independent of the drop front velocity up to approximately 10 mm/min. This agrees with the results of an earlier study that showed that the rate-dependence of the contact angles is an issue only

  4. Visual Earth observation performance in the space environment. Human performance measurement 4: Flight experiments

    NASA Technical Reports Server (NTRS)

    Huth, John F.; Whiteley, James D.; Hawker, John E.

    1993-01-01

    A wide variety of secondary payloads have flown on the Space Transportation System (STS) since its first flight in the 1980's. These experiments have typically addressed specific issues unique to the zero-gravity environment. Additionally, the experiments use the experience and skills of the mission and payload specialist crew members to facilitate data collection and ensure successful completion. This paper presents the results of the Terra Scout experiment, which flew aboard STS-44 in November 1991. This unique Earth Observation experiment specifically required a career imagery analyst to operate the Spaceborne Direct-View Optical System (SpaDVOS), a folded optical path telescope system designed to mount inside the shuttle on the overhead aft flight deck windows. Binoculars and a small telescope were used as backup optics. Using his imagery background, coupled with extensive target and equipment training, the payload specialist was tasked with documenting the following: (1) the utility of the equipment; (2) his ability to acquire and track ground targets; (3) the level of detail he could discern; (4) the atmospheric conditions; and (5) other in-situ elements which contributed to or detracted from his ability to analyze targets. Special emphasis was placed on the utility of a manned platform for research and development of future spaceborne sensors. The results and lessons learned from Terra Scout will be addressed including human performance and equipment design issues.

  5. Experiment on the Vernov satellite: Transient energetic processes in the Earth's atmosphere and magnetosphere. Part I: Description of the experiment

    NASA Astrophysics Data System (ADS)

    Panasyuk, M. I.; Svertilov, S. I.; Bogomolov, V. V.; Garipov, G. K.; Barinova, V. O.; Bogomolov, A. V.; Veden'kin, N. N.; Golovanov, I. A.; Iyudin, A. F.; Kalegaev, V. V.; Klimov, P. A.; Kovtyukh, A. S.; Kuznetsova, E. A.; Morozenko, V. S.; Morozov, O. V.; Myagkova, I. N.; Petrov, V. L.; Prokhorov, A. V.; Rozhkov, G. V.; Sigaeva, E. A.; Khrenov, B. A.; Yashin, I. V.; Klimov, S. I.; Vavilov, D. I.; Grushin, V. A.; Grechko, T. V.; Khartov, V. V.; Kudryashov, V. A.; Bortnikov, S. V.; Mzhel'skiy, P. V.; Papkov, A. P.; Krasnopeev, S. V.; Krug, V. V.; Korepanov, V. E.; Belyaev, S.; Demidov, A.; Ferenz, Ch.; Bodnar, L.; Szegedi, P.; Rotkel, H.; Moravskiy, M.; Park, Il; Jeon, Jin-A.; Kim, Ji-In; Lee, Jik

    2016-07-01

    The program of physical studies on the Vernov satellite launched on July 8, 2014 into a polar (640 × 830 km) solar-synchronous orbit with an inclination of 98.4° is presented. We described the complex of scientific equipment on this satellite in detail, including multidirectional gamma-ray detectors, electron spectrometers, red and ultra-violet detectors, and wave probes. The experiment on the Vernov satellite is mainly aimed at a comprehensive study of the processes of generation of transient phenomena in the optical and gamma-ray ranges in the Earth's atmosphere (such as high-altitude breakdown on runaway relativistic electrons), the study of the action on the atmosphere of electrons precipitated from the radiation belts, and low- and high-frequency electromagnetic waves of both space and atmospheric origin.

  6. Tendon-Driven Continuum Robot for Neuroendoscopy: Validation of Extended Kinematic Mapping for Hysteresis Operation

    PubMed Central

    Takahisa, Kato; Okumura, Ichiro; Kose, Hidekazu; Takagi, Kiyoshi; Hata, Nobuhiko

    2016-01-01

    Purpose The hysteresis operation is an outstanding issue in tendon-driven actuation—which is used in robot-assisted surgery—as it is incompatible with kinematic mapping for control and trajectory planning. Here, a new tendon-driven continuum robot, designed to fit existing neuroendoscopes, is presented with kinematic mapping for hysteresis operation. Methods With attention to tension in tendons as a salient factor of the hysteresis operation, extended forward kinematic mapping (FKM) has been developed. In the experiment, the significance of every component in the robot for the hysteresis operation has been investigated. Moreover, the prediction accuracy of postures by the extended FKM has been determined experimentally and compared with piecewise constant curvature assumption (PCCA). Results The tendons were the most predominant factor affecting the hysteresis operation of the robot. The extended FKM including friction in tendons predicted the postures in the hysteresis operation with improved accuracy (2.89 mm and 3.87 mm for the single and the antagonistic tendons layouts, respectively). The measured accuracy was within the target value of 5 mm for planning of neuroendoscopic resection of intraventricle tumors. Conclusion The friction in tendons was the most predominant factor for the hysteresis operation in the robot. The extended FKM including this factor can improve prediction accuracy of the postures in the hysteresis operation. The trajectory of the new robot can be planned within target value for the neuroendoscopic procedure by using the extended FKM. PMID:26476639

  7. Tendon-driven continuum robot for neuroendoscopy: validation of extended kinematic mapping for hysteresis operation.

    PubMed

    Kato, Takahisa; Okumura, Ichiro; Kose, Hidekazu; Takagi, Kiyoshi; Hata, Nobuhiko

    2016-04-01

    The hysteresis operation is an outstanding issue in tendon-driven actuation--which is used in robot-assisted surgery--as it is incompatible with kinematic mapping for control and trajectory planning. Here, a new tendon-driven continuum robot, designed to fit existing neuroendoscopes, is presented with kinematic mapping for hysteresis operation. With attention to tension in tendons as a salient factor of the hysteresis operation, extended forward kinematic mapping (FKM) has been developed. In the experiment, the significance of every component in the robot for the hysteresis operation has been investigated. Moreover, the prediction accuracy of postures by the extended FKM has been determined experimentally and compared with piecewise constant curvature assumption. The tendons were the most predominant factor affecting the hysteresis operation of the robot. The extended FKM including friction in tendons predicted the postures in the hysteresis operation with improved accuracy (2.89 and 3.87 mm for the single and the antagonistic-tendons layouts, respectively). The measured accuracy was within the target value of 5 mm for planning of neuroendoscopic resection of intraventricle tumors. The friction in tendons was the most predominant factor for the hysteresis operation in the robot. The extended FKM including this factor can improve prediction accuracy of the postures in the hysteresis operation. The trajectory of the new robot can be planned within target value for the neuroendoscopic procedure by using the extended FKM.

  8. Molecular mechanism of adsorption/desorption hysteresis: dynamics of shale gas in nanopores

    NASA Astrophysics Data System (ADS)

    Chen, Jie; Wang, FengChao; Liu, He; Wu, HengAn

    2017-01-01

    Understanding the adsorption and desorption behavior of methane has received considerable attention since it is one of the crucial aspects of the exploitation of shale gas. Unexpectedly, obvious hysteresis is observed from the ideally reversible physical sorption of methane in some experiments. However, the underlying mechanism still remains an open problem. In this study, Monte Carlo (MC) and molecular dynamics (MD) simulations are carried out to explore the molecular mechanisms of adsorption/desorption hysteresis. First, a detailed analysis about the capillary condensation of methane in micropores is presented. The influence of pore width, surface strength, and temperature on the hysteresis loop is further investigated. It is found that a disappearance of hysteresis occurs above a temperature threshold. Combined with the phase diagram of methane, we explicitly point out that capillary condensation is inapplicable for the hysteresis of shale gas under normal temperature conditions. Second, a new mechanism, variation of pore throat size, is proposed and studied. For methane to pass through the throat, a certain energy is required due to the repulsive interaction. The required energy increases with shrinkage of the throat, such that the originally adsorbed methane cannot escape through the narrowed throat. These trapped methane molecules account for the hysteresis. Furthermore, the hysteresis loop is found to increase with the increasing pressure and decreasing temperature. We suggest that the variation of pore throat size can explain the adsorption/desorption hysteresis of shale gas. Our conclusions and findings are of great significance for guiding the efficient exploitation of shale gas.

  9. Molecular mechanism of adsorption/desorption hysteresis: dynamics of shale gas in nanopores

    NASA Astrophysics Data System (ADS)

    Chen, Jie; Wang, FengChao; Liu, He; Wu, HengAn

    2017-01-01

    Understanding the adsorption and desorption behavior of methane has received considerable attention since it is one of the crucial aspects of the exploitation of shale gas. Unexpectedly, obvious hysteresis is observed from the ideally reversible physical sorption of methane in some experiments. However, the underlying mechanism still remains an open problem. In this study, Monte Carlo (MC) and molecular dynamics (MD) simulations are carried out to explore the molecular mechanisms of adsorption/desorption hysteresis. First, a detailed analysis about the capillary condensation of methane in micropores is presented. The influence of pore width, surface strength, and temperature on the hysteresis loop is further investigated. It is found that a disappearance of hysteresis occurs above a temperature threshold. Combined with the phase diagram of methane, we explicitly point out that capillary condensation is inapplicable for the hysteresis of shale gas under normal temperature conditions. Second, a new mechanism, variation of pore throat size, is proposed and studied. For methane to pass through the throat, a certain energy is required due to the repulsive interaction. The required energy increases with shrinkage of the throat, such that the originally adsorbed methane cannot escape through the narrowed throat. These trapped methane molecules account for the hysteresis. Furthermore, the hysteresis loop is found to increase with the increasing pressure and decreasing temperature. We suggest that the variation of pore throat size can explain the adsorption/desorption hysteresis of shale gas. Our conclusions and findings are of great significance for guiding the efficient exploitation of shale gas.

  10. High-speed tracking control of piezoelectric actuators using an ellipse-based hysteresis model.

    PubMed

    Gu, Guoying; Zhu, Limin

    2010-08-01

    In this paper, an ellipse-based mathematic model is developed to characterize the rate-dependent hysteresis in piezoelectric actuators. Based on the proposed model, an expanded input space is constructed to describe the multivalued hysteresis function H[u](t) by a multiple input single output (MISO) mapping Gamma:R(2)-->R. Subsequently, the inverse MISO mapping Gamma(-1)(H[u](t),H[u](t);u(t)) is proposed for real-time hysteresis compensation. In controller design, a hybrid control strategy combining a model-based feedforward controller and a proportional integral differential (PID) feedback loop is used for high-accuracy and high-speed tracking control of piezoelectric actuators. The real-time feedforward controller is developed to cancel the rate-dependent hysteresis based on the inverse hysteresis model, while the PID controller is used to compensate for the creep, modeling errors, and parameter uncertainties. Finally, experiments with and without hysteresis compensation are conducted and the experimental results are compared. The experimental results show that the hysteresis compensation in the feedforward path can reduce the hysteresis-caused error by up to 88% and the tracking performance of the hybrid controller is greatly improved in high-speed tracking control applications, e.g., the root-mean-square tracking error is reduced to only 0.34% of the displacement range under the input frequency of 100 Hz.

  11. Characteristics of the Nordic Seas overflows in a set of Norwegian Earth System Model experiments

    NASA Astrophysics Data System (ADS)

    Guo, Chuncheng; Ilicak, Mehmet; Bentsen, Mats; Fer, Ilker

    2016-08-01

    Global ocean models with an isopycnic vertical coordinate are advantageous in representing overflows, as they do not suffer from topography-induced spurious numerical mixing commonly seen in geopotential coordinate models. In this paper, we present a quantitative diagnosis of the Nordic Seas overflows in four configurations of the Norwegian Earth System Model (NorESM) family that features an isopycnic ocean model. For intercomparison, two coupled ocean-sea ice and two fully coupled (atmosphere-land-ocean-sea ice) experiments are considered. Each pair consists of a (non-eddying) 1° and a (eddy-permitting) 1/4° horizontal resolution ocean model. In all experiments, overflow waters remain dense and descend to the deep basins, entraining ambient water en route. Results from the 1/4° pair show similar behavior in the overflows, whereas the 1° pair show distinct differences, including temperature/salinity properties, volume transport (Q), and large scale features such as the strength of the Atlantic Meridional Overturning Circulation (AMOC). The volume transport of the overflows and degree of entrainment are underestimated in the 1° experiments, whereas in the 1/4° experiments, there is a two-fold downstream increase in Q, which matches observations well. In contrast to the 1/4° experiments, the coarse 1° experiments do not capture the inclined isopycnals of the overflows or the western boundary current off the Flemish Cap. In all experiments, the pathway of the Iceland-Scotland Overflow Water is misrepresented: a major fraction of the overflow proceeds southward into the West European Basin, instead of turning westward into the Irminger Sea. This discrepancy is attributed to excessive production of Labrador Sea Water in the model. The mean state and variability of the Nordic Seas overflows have significant consequences on the response of the AMOC, hence their correct representations are of vital importance in global ocean and climate modelling.

  12. MATHEMATICAL MODELS OF HYSTERESIS (DYNAMIC PROBLEMS IN HYSTERESIS)

    SciTech Connect

    Professor Isaak Mayergoyz

    2006-08-21

    This research has further advanced the current state of the art in the areas of dynamic aspects of hysteresis and nonlinear large scale magnetization dynamics. The results of this research will find important engineering applications in the areas of magnetic data storage technology and the emerging technology of “spintronics”. Our research efforts have been focused on the following tasks: • Study of fast (pulse) precessional switching of magnetization in magnetic materials. • Analysis of critical fields and critical angles for precessional switching of magnetization. • Development of inverse problem approach to the design of magnetic field pulses for precessional switching of magnetization. • Study of magnetization dynamics induced by spin polarized current injection. • Construction of complete stability diagrams for spin polarized current induced magnetization dynamics. • Development of the averaging technique for the analysis of the slow time scale magnetization dynamics. • Study of thermal effects on magnetization dynamics by using the theory of stochastic processes on graphs.

  13. Benchmark Shock Tube Experiments for Radiative Heating Relevant to Earth Re-Entry

    NASA Technical Reports Server (NTRS)

    Brandis, A. M.; Cruden, B. A.

    2017-01-01

    Detailed spectrally and spatially resolved radiance has been measured in the Electric Arc Shock Tube (EAST) facility for conditions relevant to high speed entry into a variety of atmospheres, including Earth, Venus, Titan, Mars and the Outer Planets. The tests that measured radiation relevant for Earth re-entry are the focus of this work and are taken from campaigns 47, 50, 52 and 57. These tests covered conditions from 8 km/s to 15.5 km/s at initial pressures ranging from 0.05 Torr to 1 Torr, of which shots at 0.1 and 0.2 Torr are analyzed in this paper. These conditions cover a range of points of interest for potential fight missions, including return from Low Earth Orbit, the Moon and Mars. The large volume of testing available from EAST is useful for statistical analysis of radiation data, but is problematic for identifying representative experiments for performing detailed analysis. Therefore, the intent of this paper is to select a subset of benchmark test data that can be considered for further detailed study. These benchmark shots are intended to provide more accessible data sets for future code validation studies and facility-to-facility comparisons. The shots that have been selected as benchmark data are the ones in closest agreement to a line of best fit through all of the EAST results, whilst also showing the best experimental characteristics, such as test time and convergence to equilibrium. The EAST data are presented in different formats for analysis. These data include the spectral radiance at equilibrium, the spatial dependence of radiance over defined wavelength ranges and the mean non-equilibrium spectral radiance (so-called 'spectral non-equilibrium metric'). All the information needed to simulate each experimental trace, including free-stream conditions, shock time of arrival (i.e. x-t) relation, and the spectral and spatial resolution functions, are provided.

  14. Cloud-radiative forcing and climate: results from the Earth radiation budget experiment.

    PubMed

    Ramanathan, V; Cess, R D; Harrison, E F; Minnis, P; Barkstrom, B R; Ahmad, E; Hartmann, D

    1989-01-06

    The study of climate and climate change is hindered by a lack of information on the effect of clouds on the radiation balance of the earth, referred to as the cloud-radiative forcing. Quantitative estimates of the global distributions of cloud-radiative forcing have been obtained from the spaceborne Earth Radiation Budget Experiment (ERBE) launched in 1984. For the April 1985 period, the global shortwave cloud forcing [-44.5 watts per square meter (W/m(2))] due to the enhancement of planetary albedo, exceeded in magnitude the longwave cloud forcing (31.3 W/m(2)) resulting from the greenhouse effect of clouds. Thus, clouds had a net cooling effect on the earth. This cooling effect is large over the mid-and high-latitude oceans, with values reaching -100 W/m(2). The monthly averaged longwave cloud forcing reached maximum values of 50 to 100 W/m(2) over the convectively disturbed regions of the tropics. However, this heating effect is nearly canceled by a correspondingly large negative shortwave cloud forcing, which indicates the delicately balanced state of the tropics. The size of the observed net cloud forcing is about four times as large as the expected value of radiative forcing from a doubling of CO(2). The shortwave and longwave components of cloud forcing are about ten times as large as those for a CO(2) doubling. Hence, small changes in the cloud-radiative forcing fields can play a significant role as a climate feedback mechanism. For example, during past glaciations a migration toward the equator of the field of strong, negative cloud-radiative forcing, in response to a similar migration of cooler waters, could have significantly amplified oceanic cooling and continental glaciation.

  15. Microwave heating device for internal heating convection experiments, applied to Earth's mantle dynamics.

    PubMed

    Surducan, E; Surducan, V; Limare, A; Neamtu, C; Di Giuseppe, E

    2014-12-01

    We report the design, construction, and performances of a microwave (MW) heating device for laboratory experiments with non-contact, homogeneous internal heating. The device generates MW radiation at 2.47 GHz from a commercial magnetron supplied by a pulsed current inverter using proprietary, feedback based command and control hardware and software. Specially designed MW launchers direct the MW radiation into the sample through a MW homogenizer, devised to even the MW power distribution into the sample's volume. An adjustable MW circuit adapts the MW generator to the load (i.e., the sample) placed in the experiment chamber. Dedicated heatsinks maintain the MW circuits at constant temperature throughout the experiment. Openings for laser scanning for image acquisition with a CCD camera and for the cooling circuits are protected by special MW filters. The performances of the device are analyzed in terms of heating uniformity, long term output power stability, and load matching. The device is used for small scale experiments simulating Earth's mantle convection. The 30 × 30 × 5 cm(3) convection tank is filled with a water‑based viscous fluid. A uniform and constant temperature is maintained at the upper boundary by an aluminum heat exchanger and adiabatic conditions apply at the tank base. We characterize the geometry of the convective regime as well as its bulk thermal evolution by measuring the velocity field by Particle Image Velocimetry and the temperature field by using Thermochromic Liquid Crystals.

  16. Microwave heating device for internal heating convection experiments, applied to Earth's mantle dynamics

    SciTech Connect

    Surducan, E.; Surducan, V.; Neamtu, C.; Limare, A.; Di Giuseppe, E.

    2014-12-15

    We report the design, construction, and performances of a microwave (MW) heating device for laboratory experiments with non-contact, homogeneous internal heating. The device generates MW radiation at 2.47 GHz from a commercial magnetron supplied by a pulsed current inverter using proprietary, feedback based command and control hardware and software. Specially designed MW launchers direct the MW radiation into the sample through a MW homogenizer, devised to even the MW power distribution into the sample's volume. An adjustable MW circuit adapts the MW generator to the load (i.e., the sample) placed in the experiment chamber. Dedicated heatsinks maintain the MW circuits at constant temperature throughout the experiment. Openings for laser scanning for image acquisition with a CCD camera and for the cooling circuits are protected by special MW filters. The performances of the device are analyzed in terms of heating uniformity, long term output power stability, and load matching. The device is used for small scale experiments simulating Earth's mantle convection. The 30 × 30 × 5 cm{sup 3} convection tank is filled with a water‑based viscous fluid. A uniform and constant temperature is maintained at the upper boundary by an aluminum heat exchanger and adiabatic conditions apply at the tank base. We characterize the geometry of the convective regime as well as its bulk thermal evolution by measuring the velocity field by Particle Image Velocimetry and the temperature field by using Thermochromic Liquid Crystals.

  17. Microwave heating device for internal heating convection experiments, applied to Earth's mantle dynamics

    NASA Astrophysics Data System (ADS)

    Surducan, E.; Surducan, V.; Limare, A.; Neamtu, C.; Di Giuseppe, E.

    2014-12-01

    We report the design, construction, and performances of a microwave (MW) heating device for laboratory experiments with non-contact, homogeneous internal heating. The device generates MW radiation at 2.47 GHz from a commercial magnetron supplied by a pulsed current inverter using proprietary, feedback based command and control hardware and software. Specially designed MW launchers direct the MW radiation into the sample through a MW homogenizer, devised to even the MW power distribution into the sample's volume. An adjustable MW circuit adapts the MW generator to the load (i.e., the sample) placed in the experiment chamber. Dedicated heatsinks maintain the MW circuits at constant temperature throughout the experiment. Openings for laser scanning for image acquisition with a CCD camera and for the cooling circuits are protected by special MW filters. The performances of the device are analyzed in terms of heating uniformity, long term output power stability, and load matching. The device is used for small scale experiments simulating Earth's mantle convection. The 30 × 30 × 5 cm3 convection tank is filled with a water-based viscous fluid. A uniform and constant temperature is maintained at the upper boundary by an aluminum heat exchanger and adiabatic conditions apply at the tank base. We characterize the geometry of the convective regime as well as its bulk thermal evolution by measuring the velocity field by Particle Image Velocimetry and the temperature field by using Thermochromic Liquid Crystals.

  18. Advanced Concepts, Technologies and Flight Experiments for NASA's Earth Science Enterprise

    NASA Technical Reports Server (NTRS)

    Meredith, Barry D.

    2000-01-01

    Over the last 25 years, NASA Langley Research Center (LaRC) has established a tradition of excellence in scientific research and leading-edge system developments, which have contributed to improved scientific understanding of our Earth system. Specifically, LaRC advances knowledge of atmospheric processes to enable proactive climate prediction and, in that role, develops first-of-a-kind atmospheric sensing capabilities that permit a variety of new measurements to be made within a constrained enterprise budget. These advances are enabled by the timely development and infusion of new, state-of-the-art (SOA), active and passive instrument and sensor technologies. In addition, LaRC's center-of-excellence in structures and materials is being applied to the technological challenges of reducing measurement system size, mass, and cost through the development and use of space-durable materials; lightweight, multi-functional structures; and large deployable/inflatable structures. NASA Langley is engaged in advancing these technologies across the full range of readiness levels from concept, to components, to prototypes, to flight experiments, and on to actual science mission infusion. The purpose of this paper is to describe current activities and capabilities, recent achievements, and future plans of the integrated science, engineering, and technology team at Langley Research Center who are working to enable the future of NASA's Earth Science Enterprise.

  19. The Geostationary Earth Radiation Budget Experiment on MSG-1 and its Potential Applications

    NASA Astrophysics Data System (ADS)

    Harries, J.; Crommelynck, D.

    1999-01-01

    The Geostationary Earth Radiation Budget Experiment (GERB) is in development for launch on the first Meteosat Second Generation Satellite (MSG1) and is described here with its main characteristics. GERB is designed to determine top of the atmosphere reflected Solar and Earth emitted fluxes, sampled every five minutes with a nadir foot print of about 50×50 km2. The measured radiances will be translated into fluxes with improved spatial resolution based on the information extracted from the SEVIRI1 instrument also flying on MSG. The applications of GERB data will be multiple. They will provide the behaviour of the real diurnal cycle radiation fields, and thus enable quantification of the cloud diurnal cycle. Together with the SEVIRI information, GERB will allow unique new insight for atmospheric energy budget research.1Spinning Enhanced Visible and Infrared Imager, the prime instrument on MSG

  20. Orbital and cloud cover sampling analyses for multisatellite earth radiation budget experiments

    NASA Technical Reports Server (NTRS)

    Harrison, E. F.; Minnis, P.; Gibson, G. G.

    1983-01-01

    Computer simulations have been performed to determine the geographical and temporal coverage of various satellite orbits and scanning and nonscanning radiometers for earth radiation budget measurements. These results were used to simulate the sampling of a diurnally varying cloud and radiation field for several different satellite systems to estimate errors in regional monthly mean reflected radiation. The combined results indicate that coincient observations with a minimum of one sun-synchronous satellite and a midinclined orbit satellite are needed to obtain the required regional, zonal, and global coverage with sufficient temporal sampling for obtaining accurate estimates of monthly mean reflected solar radiation. Overall, the best sampling capability and lowest errors were obtained with a three-satellite system, i.e., two sun-synchronous satellites with different equatorial crossing times combined with either a 46 or 57-deg orbit satellite. The results from these analyses have been used in defining a joint NASA-NOAA multisatellite mission for an earth radiation budget experiment.

  1. The UAH Spinning Terrella Experiment: A Laboratory Analog for the Earth's Magnetosphere

    NASA Technical Reports Server (NTRS)

    Sheldon, R. B.; Gallagher, D. L.; Craven, P. D.; Whitaker, Ann F. (Technical Monitor)

    2001-01-01

    The UAH Spinning Terrella Experiment has been modified to include the effect of a second magnet. This is a simple laboratory demonstration of the well-known double-dipole approximation to the Earth's magnetosphere. In addition, the magnet has been biassed $\\sim$-400V which generates a DC glow discharge and traps it in a ring current around the magnet. This ring current is easily imaged with a digital camera and illustrates several significant topological properties of a dipole field. In particular, when the two dipoles are aligned, and therefore repel, they emulate a northward IMF Bz magnetosphere. Such a geometry traps plasma in the high latitude cusps as can be clearly seen in the movies. Likewise, when the two magnets are anti-aligned, they emulate a southward IMF Bz magnetosphere with direct feeding of plasma through the x-line. We present evidence for trapping and heating of the plasma, comparing the dipole-trapped ring current to the cusp-trapped population. We also present a peculiar asymmetric ring current produced in by the plasma at low plasma densities. We discuss the similarities and dissimilarities of the laboratory analog to the collisionless Earth plasma, and implications for the interpretation of IMAGE data.

  2. Radiation in the Near-Earth Space: Results of RELEC Experiment on board Vernov Mission

    NASA Astrophysics Data System (ADS)

    Svertilov, Sergiey

    2015-04-01

    The main goal of RELEC mission is study of magnetosphere relativistic electron precipitation with it possible connection with Atmosphere transient luminous events as well as the monitor observation of radiation and electromagnetic environment in the near-Earth Space. The RELEC set of instruments includes two identical detectors of X- and gamma-rays of high temporal resolution and sensitivity (DRGE-1 & DRGE-2), three axe directed detectors of energetic electrons and protons DRGE-3, UV TLE imager MTEL, UV detector DUV, low-frequency analyser LFA, radio-frequency analyser RFA, module of electronics intended for commands and data collection BE. During the RELEC mission following experiments will be provided: - simultaneous observations of energetic electron & proton flux (energy range ~0.1-10.0 MeV and low-frequency (~0.1-10 kHz) electromagnetic wave field intensity variations with high temporal resolution (~1 mcs); - fine time structure (~10 mcs) measurements of transient atmospheric events in UV, X- and gamma rays with a possibility of optical imaging with resolution of ~km in wide FOV; - measurements of electron flux pitch-angle distribution in dynamical range from ~0.1 up to 105 part/cm2s; - monitoring of charge and neutral background particles in different areas of near-Earth space. The small satellite with RELEC instruments was successfully launched July, 8 2014. The mission orbit is solar-synchronous with apogee 830 lm, perigee 640 km, inclination 98.4o and orbital period about 100 min.

  3. Partitioning experiments in the laser-heated diamond anvil cell: volatile content in the Earth's core.

    PubMed

    Jephcoat, Andrew P; Bouhifd, M Ali; Porcelli, Don

    2008-11-28

    The present state of the Earth evolved from energetic events that were determined early in the history of the Solar System. A key process in reconciling this state and the observable mantle composition with models of the original formation relies on understanding the planetary processing that has taken place over the past 4.5Ga. Planetary size plays a key role and ultimately determines the pressure and temperature conditions at which the materials of the early solar nebular segregated. We summarize recent developments with the laser-heated diamond anvil cell that have made possible extension of the conventional pressure limit for partitioning experiments as well as the study of volatile trace elements. In particular, we discuss liquid-liquid, metal-silicate (M-Sil) partitioning results for several elements in a synthetic chondritic mixture, spanning a wide range of atomic number-helium to iodine. We examine the role of the core as a possible host of both siderophile and trace elements and the implications that early segregation processes at deep magma ocean conditions have for current mantle signatures, both compositional and isotopic. The results provide some of the first experimental evidence that the core is the obvious replacement for the long-sought, deep mantle reservoir. If so, they also indicate the need to understand the detailed nature and scale of core-mantle exchange processes, from atomic to macroscopic, throughout the age of the Earth to the present day.

  4. The UAH Spinning Terrella Experiment: A Laboratory Analog for the Earth's Magnetosphere

    NASA Technical Reports Server (NTRS)

    Sheldon, R. B.; Gallagher, D. L.; Craven, P. D.; Whitaker, Ann F. (Technical Monitor)

    2001-01-01

    The UAH Spinning Terrella Experiment has been modified to include the effect of a second magnet. This is a simple laboratory demonstration of the well-known double-dipole approximation to the Earth's magnetosphere. In addition, the magnet has been biassed $\\sim$-400V which generates a DC glow discharge and traps it in a ring current around the magnet. This ring current is easily imaged with a digital camera and illustrates several significant topological properties of a dipole field. In particular, when the two dipoles are aligned, and therefore repel, they emulate a northward IMF Bz magnetosphere. Such a geometry traps plasma in the high latitude cusps as can be clearly seen in the movies. Likewise, when the two magnets are anti-aligned, they emulate a southward IMF Bz magnetosphere with direct feeding of plasma through the x-line. We present evidence for trapping and heating of the plasma, comparing the dipole-trapped ring current to the cusp-trapped population. We also present a peculiar asymmetric ring current produced in by the plasma at low plasma densities. We discuss the similarities and dissimilarities of the laboratory analog to the collisionless Earth plasma, and implications for the interpretation of IMAGE data.

  5. Perovskite–fullerene hybrid materials suppress hysteresis in planar diodes

    PubMed Central

    Xu, Jixian; Buin, Andrei; Ip, Alexander H.; Li, Wei; Voznyy, Oleksandr; Comin, Riccardo; Yuan, Mingjian; Jeon, Seokmin; Ning, Zhijun; McDowell, Jeffrey J.; Kanjanaboos, Pongsakorn; Sun, Jon-Paul; Lan, Xinzheng; Quan, Li Na; Kim, Dong Ha; Hill, Ian G.; Maksymovych, Peter; Sargent, Edward H.

    2015-01-01

    Solution-processed planar perovskite devices are highly desirable in a wide variety of optoelectronic applications; however, they are prone to hysteresis and current instabilities. Here we report the first perovskite–PCBM hybrid solid with significantly reduced hysteresis and recombination loss achieved in a single step. This new material displays an efficient electrically coupled microstructure: PCBM is homogeneously distributed throughout the film at perovskite grain boundaries. The PCBM passivates the key PbI3− antisite defects during the perovskite self-assembly, as revealed by theory and experiment. Photoluminescence transient spectroscopy proves that the PCBM phase promotes electron extraction. We showcase this mixed material in planar solar cells that feature low hysteresis and enhanced photovoltage. Using conductive AFM studies, we reveal the memristive properties of perovskite films. We close by positing that PCBM, by tying up both halide-rich antisites and unincorporated halides, reduces electric field-induced anion migration that may give rise to hysteresis and unstable diode behaviour. PMID:25953105

  6. Hysteresis in the phase-slip state of superconducting filaments

    NASA Astrophysics Data System (ADS)

    Kramer, Lorenz; Rangel, Rafael

    1989-04-01

    Recently some papers on measurements of the I-V characteristics (where V is the time-averaged voltage) of superconducting indium microbridges 1 as well as tin and zinc whiskers 2,3 driven by a dc current into the phase-slip state have appeared. Special emphasis was placed on a discussion of the hysteresis, which is well-known in such experiments (see, e.g., Refs. 1 18 in Kramer and Rangel 4 ). The hysteresis was compared with the predictions of the generalized time-dependent Ginzburg-Landau (GTDGL) equations for dirty superconductors in local equilibrium. 4,5 Unfortunately these predictions represent the only results in this context derived ultimately in a rigorous fashion from the standard microscopic theory of superconductivity. Comparison was also made with a model by Kadin, Smith, and Skocpol (KSS), 6,7 which gives a much smaller hysteresis. The authors of Ref. 1 found good agreement with the KSS model. The authors of Refs. 2 and 3 found a hysteresis which is larger than that of the KSS model, but still considerably smaller than predicted by GTDGL theory. They proposed a generalization of KSS which can be fitted to the data.

  7. Perovskite-Fullerene Hybrid Materials Eliminate Hysteresis In Planar Diodes

    DOE PAGES

    Xu, Jixian; Buin, Andrei; Ip, Alexander H.; ...

    2015-03-31

    Solution-processed planar perovskite devices are highly desirable in a wide variety of optoelectronic applications; however, they are prone to hysteresis and current instabilities. Here we report the first perovskite–PCBM hybrid solid with significantly reduced hysteresis and recombination loss achieved in a single step. This new material displays an efficient electrically coupled microstructure: PCBM is homogeneously distributed throughout the film at perovskite grain boundaries. The PCBM passivates the key PbI3 antisite defects during the perovskite self-assembly, as revealed by theory and experiment. Photoluminescence transient spectroscopy proves that the PCBM phase promotes electron extraction. We showcase this mixed material in planar solarmore » cells that feature low hysteresis and enhanced photovoltage. Using conductive AFM studies, we reveal the memristive properties of perovskite films. We close by positing that PCBM, by tying up both halide-rich antisites and unincorporated halides, reduces electric field-induced anion migration that may give rise to hysteresis and unstable diode behaviour.« less

  8. Possibility to increase the purity of Michelson's experience to determine the influence of Earth's motion on light velocity

    NASA Astrophysics Data System (ADS)

    Nurmukhametov, V. A.

    2000-01-01

    It is shown that Michelson's experience on the determination of influence of Earth's motion on the light velocity admits twofold interpretation of obtained result. It is proposed to increase the experience purity by way of separate passage of direct and reverse light beams through both interferometer arms.

  9. Position control of a single pneumatic artificial muscle with hysteresis compensation based on modified Prandtl-Ishlinskii model.

    PubMed

    Zang, Xizhe; Liu, Yixiang; Heng, Shuai; Lin, Zhenkun; Zhao, Jie

    2017-01-01

    High-performance position control of pneumatic artificial muscles is limited by their inherent nonlinearity and hysteresis. This study aims to model the length/pressure hysteresis of a single pneumatic artificial muscle and to realize its accurate position tracking control with forward hysteresis compensation. The classical Prandtl-Ishlinskii model is widely used in hysteresis modelling and compensation. But it is only effective for symmetric hysteresis. Therefore, a modified Prandtl-Ishlinskii model is built to characterize the asymmetric length/pressure hysteresis of a single pneumatic artificial muscle, by replacing the classical play operators with two more flexible elementary operators to independently describe the ascending branch and descending branch of hysteresis loops. On the basis, a position tracking controller, which is composed of cascade forward hysteresis compensation and simple proportional pressure controller, is designed for the pneumatic artificial muscle. Experiment results show that the MPI model can reproduce the length/pressure hysteresis of the pneumatic artificial muscle, and the proposed controller for the pneumatic artificial muscle can track the reference position signals with high accuracy. By modelling the length/pressure hysteresis with the modified Prandtl-Ishlinskii model and using its inversion for compensation, precise position control of a single pneumatic artificial muscle is achieved.

  10. Stability of the Earth Radiation Budget Experiment scanner results for the first two years of multiple-satellite operation

    NASA Technical Reports Server (NTRS)

    Staylor, W. Frank

    1993-01-01

    Clear-sky albedos and outgoing longwave radiation (OLR) determined from Earth Radiation Budget Experiment (ERBE) scanners on board the earth radiation budget satellite and NOAA-9 spacecraft were analyzed for three target sites for the months February 1985-January 1987. The targets were oceans, deserts, and a multiscene site covering half the earth's surface. Year-to-year ratios of the monthly albedos and OLR were within the 0.98-1.02 range with a standard error of about 1%. The data indicate that ERBE scanner measurements were stable to within a few tenths of a percent for the two-year periods.

  11. RELEC Experiment on board Vernov Satellite: Relativistic Electron Flux Dynamics in Near-Earth Space

    NASA Astrophysics Data System (ADS)

    Svertilov, Sergiey

    2015-04-01

    The main goal of RELEC mission is study of magnetosphere relativistic electron precipitation with it possible acting on the upper atmosphere and ionosphere as well as the monitor observation of radiation and electromagnetic environment in the near-Earth Space. The RELEC set of instruments includes two identical detectors of X- and gamma-rays of high temporal resolution and sensitivity (DRGE-1 & DRGE-2), three axe directed detectors of energetic electrons and protons DRGE-3, UV TLE imager MTEL, UV detector DUV, low-frequency analyser LFA, radio-frequency analyser RFA, module of electronics intended for commands and data collection BE. The small satellite now named Vernov with RELEC instruments was successfully launched July, 8 2014. The mission orbit is solar-synchronous with apogee 830 km, perigee 640 km, inclination 98.4o and orbital period about 100 min. The total data output is about 1.2 Gbyte per day. The fluxes and spectra of electrons in the wide energy range from 0.2 to 15 MeV are measured with the use of three detectors with axe normally directed to each other: to the local zenith, opposite to the satellite velocity vector and along the direction added two previous to the Cartesian system. Due to such detector system it is possible to estimate the electron flux anisotropy. The wide dynamical range from ~1 up to 104 part/cm2s and fine time resolution (~10 mcs) allows observations of trapped, quasi-trapped and precipitated electron flux and spectral variations in different areas in the near-Earth space including low L-shells. Comparative analysis of electron fluxes measured by RELEC with experimental data on electron detection in the experiments on board the spacecraft Electro-L with geostationary orbit, and Meteor-M2 with 800 km altitude circular polar orbit similar to Vernov allows to reconstruct the energetic electron spatial distribution in the near-Earth space. A comparison will be held for periods of moderate geomagnetic disturbances of August 26

  12. Earth resources programs at the Langley Research Center. Part 1: Advanced Applications Flight Experiments (AAFE) and microwave remote sensing program

    NASA Technical Reports Server (NTRS)

    Parker, R. N.

    1972-01-01

    The earth resources activity is comprised of two basic programs as follows: advanced applications flight experiments, and microwave remote sensing. The two programs are in various stages of implementation, extending from experimental investigations within both the AAFE program and the microwave remote sensing program, to multidisciplinary studies and planning. The purpose of this paper is simply to identify the main thrust of the Langley Research Center activity in earth resources.

  13. Hysteresis in Pressure-Driven DNA Denaturation

    PubMed Central

    Hernández-Lemus, Enrique; Nicasio-Collazo, Luz Adriana; Castañeda-Priego, Ramón

    2012-01-01

    In the past, a great deal of attention has been drawn to thermal driven denaturation processes. In recent years, however, the discovery of stress-induced denaturation, observed at the one-molecule level, has revealed new insights into the complex phenomena involved in the thermo-mechanics of DNA function. Understanding the effect of local pressure variations in DNA stability is thus an appealing topic. Such processes as cellular stress, dehydration, and changes in the ionic strength of the medium could explain local pressure changes that will affect the molecular mechanics of DNA and hence its stability. In this work, a theory that accounts for hysteresis in pressure-driven DNA denaturation is proposed. We here combine an irreversible thermodynamic approach with an equation of state based on the Poisson-Boltzmann cell model. The latter one provides a good description of the osmotic pressure over a wide range of DNA concentrations. The resulting theoretical framework predicts, in general, the process of denaturation and, in particular, hysteresis curves for a DNA sequence in terms of system parameters such as salt concentration, density of DNA molecules and temperature in addition to structural and configurational states of DNA. Furthermore, this formalism can be naturally extended to more complex situations, for example, in cases where the host medium is made up of asymmetric salts or in the description of the (helical-like) charge distribution along the DNA molecule. Moreover, since this study incorporates the effect of pressure through a thermodynamic analysis, much of what is known from temperature-driven experiments will shed light on the pressure-induced melting issue. PMID:22496765

  14. Hysteresis rarefaction in the Riemann problem

    NASA Astrophysics Data System (ADS)

    Krejčí, P.

    2008-11-01

    We consider the wave equation with Preisach hysteresis and Riemann initial data as a model for wave propagation in hysteretic (e.g. elastoplastic) media. The main result consists in proving that in the convex hysteresis loop domain, there exists a unique self-similar locally Lipschitz continuous solution. In other words, smooth rarefaction waves propagate in both directions from the initial jump discontinuity.

  15. Mississippi Sound remote sensing study. [NASA Earth Resources Laboratory seasonal experiments

    NASA Technical Reports Server (NTRS)

    Atwell, B. H.; Thomann, G. C.

    1973-01-01

    A study of the Mississippi Sound was initiated in early 1971 by personnel of NASA Earth Resources Laboratory. Four separate seasonal experiments consisting of quasi-synoptic remote and surface measurements over the entire area were planned. Approximately 80 stations distributed throughout Mississippi Sound were occupied. Surface water temperature and secchi extinction depth were measured at each station and water samples were collected for water quality analyses. The surface distribution of three water parameters of interest from a remote sensing standpoint - temperature, salinity and chlorophyll content - are displayed in map form. Areal variations in these parameters are related to tides and winds. A brief discussion of the general problem of radiative measurements of water temperature is followed by a comparison of remotely measured temperatures (PRT-5) to surface vessel measurements.

  16. Mississippi Sound remote sensing study. [NASA Earth Resources Laboratory seasonal experiments

    NASA Technical Reports Server (NTRS)

    Atwell, B. H.; Thomann, G. C.

    1973-01-01

    A study of the Mississippi Sound was initiated in early 1971 by personnel of NASA Earth Resources Laboratory. Four separate seasonal experiments consisting of quasi-synoptic remote and surface measurements over the entire area were planned. Approximately 80 stations distributed throughout Mississippi Sound were occupied. Surface water temperature and secchi extinction depth were measured at each station and water samples were collected for water quality analyses. The surface distribution of three water parameters of interest from a remote sensing standpoint - temperature, salinity and chlorophyll content - are displayed in map form. Areal variations in these parameters are related to tides and winds. A brief discussion of the general problem of radiative measurements of water temperature is followed by a comparison of remotely measured temperatures (PRT-5) to surface vessel measurements.

  17. Skylab program earth resources experiment package: Ground truth data for test sites (SL-2)

    NASA Technical Reports Server (NTRS)

    1975-01-01

    Field measurements were performed at selected ground sites in order to provide comparative calibration measurements of sensors for the Earth Resources Experiment Package. Specifically, the solar radiation (400 to 1300 namometers) and thermal radiation (8-14 micrometers) were measured. Sites employed for the thermal measurements consisted of warm and cold water lakes. The thermal brightness temperature of the lake water, the temperature and humidity profile above the lake, and near surface meteorology (wind speed, pressure, etc.) were measured near the time of overpass. Sites employed for the solar radiation measurements were two desert type sites. Ground measurements consisted of: (1) direct solar radiation - optical depth; (2) diffuse solar radiation; (3) total solar radiation, (4) target directional (normal) reflectance; (5) target hemispherical reflectance; and (6) near surface meteorology.

  18. The GSFC 20 and 30 GHz millimeter wave propagation experiment. [of earth-space communication links

    NASA Technical Reports Server (NTRS)

    Ippolito, L. J.

    1975-01-01

    The preliminary results of the Goddard Space Flight Center Millimeter Wave Experiment, flown aboard ATS-6 to investigate the propagation characteristics of earth-space communications links at 20 and 30 GHz, are discussed. The spacecraft transmitters operate through spot beam (2 deg) or continental coverage (6 by 9 deg) antenna systems. The transmitted signals consist of a set of nine tones spaced out to 1440 MHz to allow measurement of wideband attenuation and coherence through precipitation. Initial data on precipitation depolarization and attenuation effects indicate that attenuation effects will exert the stronger influence on the design of frequency re-use communications systems in the 20 GHz region. The use of four ground terminals separated by 30 to 78 km to reduce the effects of rain attenuation has been successful, with improvement approaching the theoretical maximum demonstrated for five events. Preliminary results on the use of on-beam radar measurements for predicting rain attenuation are encouraging.

  19. Consistency of Earth Radiation Budget Experiment bidirectional models and the observed anisotropy of reflected sunlight

    NASA Technical Reports Server (NTRS)

    Baldwin, Daniel G.; Coakley, James A., Jr.

    1991-01-01

    The anisotropy of the radiance field estimated from bidirectional models derived from Nimbus 7 ERB scanner data is compared with the anisotropy observed with the ERB Experiment (ERBE) scanner aboard the ERB satellite. The results of averaging over groups of 40 ERBE scanner scan lines for a period of a month revealed significant differences between the modeled and the observed anisotropy for given scene types and the sun-earth-satellite viewing geometries. By comparing the radiative fluxes derived using the observed anisotropy with those derived assuming isotropic reflection, it is concluded that a reasonable estimate for the maximum error due to the use of incorrect bidirectional models is a bias of about 4 percent for a typical 2.5 deg latitude-longitude monthly mean, and an rms error of 15 percent.

  20. Shuttle imaging radar views the Earth from Challenger: The SIR-B experiment

    NASA Technical Reports Server (NTRS)

    Ford, J. P.; Cimino, J. B.; Holt, B.; Ruzek, M. R.

    1986-01-01

    In October 1984, SIR-B obtained digital image data of about 6.5 million km2 of the Earth's surface. The coverage is mostly of selected experimental test sites located between latitudes 60 deg north and 60 deg south. Programmed adjustments made to the look angle of the steerable radar antenna and to the flight attitude of the shuttle during the mission permitted collection of multiple-incidence-angle coverage or extended mapping coverage as required for the experiments. The SIR-B images included here are representative of the coverage obtained for scientific studies in geology, cartography, hydrology, vegetation cover, and oceanography. The relations between radar backscatter and incidence angle for discriminating various types of surfaces, and the use of multiple-incidence-angle SIR-B images for stereo measurement and viewing, are illustrated with examples. Interpretation of the images is facilitated by corresponding images or photographs obtained by different sensors or by sketch maps or diagrams.

  1. The earth radiation budget derived from the Nimbus 7 ERB experiment

    NASA Technical Reports Server (NTRS)

    Jacobowitz, H.; Stowe, L. L.; Tighe, R. J.; Arking, A.; Campbell, G.; Hickey, J. R.; House, F.; Ingersoll, A.; Maschhoff, R.; Smith, G. L.

    1984-01-01

    The earth radiation budget as determined from the ERB experiment aboard the Nimbus-7 polar-orbiting satellite is presented in the form of time-latitude cross sections, hemispherically and globally averaged time plots, and annual global averages for the time period spanning November 1978 through October 1979. Comparisons are made between results derived from the fixed wide-field-of-view (WFOV) radiometers and those derived from the scanning narrow-field-of-view (NFOV) radiometers. While there is excellent agreement in regard to the spatial and temporal variations, the absolute magnitudes differ. The NFOV yields outgoing longwave fluxes and albedos that are about 4W/sq m and 2.5 percent, respectively, greater than those derived from the WFOV sensors. Also, limited simultaneous comparisons are made between ERB results and those from the AVHRR on the NOAA-7 operational satellite.

  2. Consistency of Earth Radiation Budget Experiment bidirectional models and the observed anisotropy of reflected sunlight

    NASA Technical Reports Server (NTRS)

    Baldwin, Daniel G.; Coakley, James A., Jr.

    1991-01-01

    The anisotropy of the radiance field estimated from bidirectional models derived from Nimbus 7 ERB scanner data is compared with the anisotropy observed with the ERB Experiment (ERBE) scanner aboard the ERB satellite. The results of averaging over groups of 40 ERBE scanner scan lines for a period of a month revealed significant differences between the modeled and the observed anisotropy for given scene types and the sun-earth-satellite viewing geometries. By comparing the radiative fluxes derived using the observed anisotropy with those derived assuming isotropic reflection, it is concluded that a reasonable estimate for the maximum error due to the use of incorrect bidirectional models is a bias of about 4 percent for a typical 2.5 deg latitude-longitude monthly mean, and an rms error of 15 percent.

  3. Science Results from Colorado Student Space Weather Experiment (CSSWE): Energetic Particle Distribution in Near Earth Environment

    NASA Astrophysics Data System (ADS)

    Li, Xinlin

    2013-04-01

    The Colorado Student Space Weather Experiment (CSSWE) is a 3-unit (10cm x 10cm x 30cm) CubeSat mission funded by the National Science Foundation, launched into a low-Earth, polar orbit on 13 September 2012 as a secondary payload under NASA's Educational Launch of Nanosatellites (ELaNa) program. The science objectives of CSSWE are to investigate the relationship of the location, magnitude, and frequency of solar flares to the timing, duration, and energy spectrum of solar energetic particles reaching Earth, and to determine the precipitation loss and the evolution of the energy spectrum of trapped radiation belt electrons. CSSWE contains a single science payload, the Relativistic Electron and Proton Telescope integrated little experiment (REPTile), which is a miniaturization of the Relativistic Electron and Proton Telescope (REPT) built at the Laboratory for Atmospheric and Space Physics for NASA/Van Allen Probes mission, which consists of two identical spacecraft, launched 30 August 2012, that traverse the heart of the radiation belts in a low inclination orbit. CSSWE's REPTile is designed to measure the directional differential flux of protons ranging from 10 to 40 MeV and electrons from 0.5 to >3.3 MeV. The commissioning phase was completed and REPTile was activated on 4 October 2012. The data are very clean, far exceeding expectations! A number of engineering challenges had to be overcome to achieve such clean measurements under the mass and power limits of a CubeSat. The CSSWE is also an ideal class project, providing training for the next generation of engineers and scientists over the full life-cycle of a satellite project.

  4. Simulation and analysis of the LUCID experiment in the Low Earth Orbit radiation environment

    NASA Astrophysics Data System (ADS)

    Whyntie, T.; Harrison, M. A.

    2014-06-01

    The Langton Ultimate Cosmic ray Intensity Detector (LUCID) experiment is a satellite-based device that will use five Timepix hybrid silicon pixel detectors to make measurements of the radiation environment at an altitude of approximately 635 km, i.e. in Low Earth Orbit (LEO). The experiment is due to launch aboard Surrey Satellite Technology Limited's (SSTL's) TechDemoSat-1 in 2014. The Timepix detectors, developed by the Medipix Collaboration, are arranged to form the five sides of a cube enclosed by a 0.7 mm thick aluminium "dome", and will be operated in Time-over-Threshold mode to allow the flux, energy and directionality of incident ionising radiation to be measured. To estimate the anticipated data rates with respect to these measurements, the LUCID experiment has been modelled using the GEANT4 software framework. As an input to these simulations, SPENVIS, ESA's Space Environment information system, was used to obtain the estimated flux of trapped protons and electrons in TechDemoSat-1's orbit with NASA's AP-8 and AE-8 models. A web portal, LUCIDITY, was developeded to allow school students from the LUCID Collaboration to manage SPENVIS flux spectra and GEANT4 input cards. The initial results reported here confirm that the LUCID's data transmission allowance is sufficient, and further work applying the techniques to more specific space radiation environments with a more sophisticated simulation is proposed.

  5. Results from the GPS Flight Experiment on the High Earth Orbit AMSAT OSCAR-40 Spacecraft

    NASA Technical Reports Server (NTRS)

    Bauer, Frank (Technical Monitor); Moreau, Michael C.; Davis, Edward P.; Carpenter, J. Russell; Kelbel, David; Davis, George W.; Axelrad, Penina

    2002-01-01

    A GPS receiver flying on the High Earth Orbit (HEO) AMSAT-OSCAR 40 (AO-40) spacecraft has been returning GPS observations from high above the altitude of the GPS constellation. AO-40, an amateur radio satellite launched November 16, 2000, is currently in a low inclination, 1000 by 59000 lan altitude orbit. This low-cost experiment utilizes a mid 1990's era, 6-channel, CIA code receiver configured with high gain receiving antennas for tracking above the GPS constellation. The receiver has performed well, despite operating significantly outside of its original design environment. It has regularly returned GPS observations from points all around the orbit, with over ten weeks of GPS tracking data collected to date. Signal to noise levels as high as 48 B-Hz have been recorded near apogee, when the spacecraft was at an altitude of close to 60000 km. GPS side lobe signals have been tracked on several occasions, primarily from Block IIR GPS satellites. Although the receiver has not computed a solution in real-time, point solutions have been computed on the ground using simultaneous measurements from four satellites. This experiment has provided important experience dealing with the many challenges inherent to GPS tracking at high altitudes, and the measurements returned are providing valuable information about the characteristics of GPS signals available for future HE0 users.

  6. Hysteresis in the dynamic perception of scenes and objects.

    PubMed

    Poltoratski, Sonia; Tong, Frank

    2014-10-01

    Scenes and objects are effortlessly processed and integrated by the human visual system. Given the distinct neural and behavioral substrates of scene and object processing, it is likely that individuals sometimes preferentially rely on one process or the other when viewing canonical "scene" or "object" stimuli. This would allow the visual system to maximize the specific benefits of these 2 types of processing. It is less obvious which of these modes of perception would be invoked during naturalistic visual transition between a focused view of a single object and an expansive view of an entire scene, particularly at intermediate views that may not be assigned readily to either stimulus category. In the current study, we asked observers to report their online perception of such dynamic image sequences, which zoomed and panned between a canonical view of a single object and an entire scene. We found a large and consistent effect of prior perception, or hysteresis, on the classification of the sequence: observers classified the sequence as an object for several seconds longer if the trial started at the object view and zoomed out, whereas scenes were perceived for longer on trials beginning with a scene view. This hysteresis effect resisted several manipulations of the movie stimulus and of the task performed, but hinged on the perceptual history built by unidirectional progression through the image sequence. Multiple experiments confirmed that this hysteresis effect was not purely decisional and was more prominent for transitions between corresponding objects and scenes than between other high-level stimulus classes. This finding suggests that the competitive mechanisms underlying hysteresis may be especially prominent in the perception of objects and scenes. We propose that hysteresis aids in disambiguating perception during naturalistic visual transitions, which may facilitate a dynamic balance between scene and object processing to enhance processing efficiency.

  7. Hysteresis and multiple stable configurations in a magnetic fluid system.

    PubMed

    Jackson, D P

    2008-05-21

    A magnetic liquid in a horizontal Hele-Shaw cell is subjected to a vertical magnetic field. The width of the magnetic fluid finger is measured as a function of applied field and compared to a theoretical model. The theoretical model uses an energy minimization procedure and predicts a double energy minimum, hysteresis, and discontinuous transitions between a circle and a finger. The experimental data set agrees very well with the theory for a well-defined magnetic fluid finger. Near the transitions, the experiments show hysteresis and support for a double energy minimum; however, the agreement is not quite so good. The discrepancy between theory and experiment near the transition region is likely due to the simplified finger model used in the theory.

  8. Feedback/feedforward control of hysteresis-compensated piezoelectric actuators for high-speed scanning applications

    NASA Astrophysics Data System (ADS)

    Liu, Yanfang; Shan, Jinjun; Gabbert, Ulrich

    2015-01-01

    This paper presents the control system design for a piezoelectric actuator (PEA) for a high-speed trajectory scanning application. First nonlinear hysteresis is compensated for by using the Maxwell resistive capacitor model. Then the linear dynamics of the hysteresis-compensated piezoelectric actuator are identified. A proportional plus integral (PI) controller is designed based on the linear system, enhanced by feedforward hysteresis compensation. It is found that the feedback controller does not always improve tracking accuracy. When the input frequency exceeds a certain value, feedforward control only may result in better control performance. Experiments are conducted, and the results demonstrate the effectiveness of the proposed control approach.

  9. Pairing Essential Climate Science with Sustainable Energy Information: the "EARTH-The Operators' Manual" experiment

    NASA Astrophysics Data System (ADS)

    Akuginow, E.; Alley, R. B.; Haines-Stiles, G.

    2010-12-01

    considerable challenge of supplying clean energy to a growing population. Additional scenes have been filmed in Brazil, Spain, China, Morocco, Scotland, and across America, including at the National Renewable Energy Lab. in Denver, CO, and New Orleans. Program 3 (presently untitled and targeted for 2012) will feature American communities seeking to increase energy efficiency and minimize carbon emissions. The Fall 2010 AGU presentation will include video clips from the series, initial findings from focus groups (coordinated by project evaluator, Rockman Et Al) as to what information has been found most compelling to potential audiences, and a description of plans being developed by the project's science center partners in San Diego CA, Portland OR, Minneapolis-St. Paul, Fort Worth TX and Raleigh NC. "EARTH-The Operators' Manual" is an experiment to determine the effectiveness of these activities to reach audiences who, according to surveys, have actually become less convinced of anthropogenic climate change, while remaining supportive of investments in advancing clean energy opportunities.

  10. 1999-2003 Shortwave Characterizations of Earth Radiation Budget Satellite (ERBS)/Earth Radiation Budget Experiment (ERBE) Broadband Active Cavity Radiometer Sensors

    NASA Technical Reports Server (NTRS)

    Lee, Robert B., III; Smith, George L.; Wong, Takmeng

    2008-01-01

    From October 1984 through May 2005, the NASA Earth Radiation Budget Satellite (ERBS/ )/Earth Radiation Budget Experiment (ERBE)ERBE nonscanning active cavity radiometers (ACR) were used to monitor long-term changes in the earth radiation budget components of the incoming total solar irradiance (TSI), earth-reflected TSI, and earth-emitted outgoing longwave radiation (OLR). From September1984 through September 1999, using on-board calibration systems, the ERBS/ERBE ACR sensor response changes, in gains and offsets, were determined from on-orbit calibration sources and from direct observations of the incoming TSI through calibration solar ports at measurement precision levels approaching 0.5 W/sq m , at satellite altitudes. On October 6, 1999, the onboard radiometer calibration system elevation drive failed. Thereafter, special spacecraft maneuvers were performed to observe cold space and the sun in order to define the post-September 1999 geometry of the radiometer measurements, and to determine the October 1999-September 2003 ERBS sensor response changes. Analyses of these special solar and cold space observations indicate that the radiometers were pointing approximately 16 degrees away from the spacecraft nadir and on the anti-solar side of the spacecraft. The special observations indicated that the radiometers responses were stable at precision levels approaching 0.5 W/sq m . In this paper, the measurement geometry determinations and the determinations of the radiometers gain and offset are presented, which will permit the accurate processing of the October 1999 through September 2003 ERBE data products at satellite and top-of-the-atmosphere altitudes.

  11. 1999-2003 Shortwave Characterizations of Earth Radiation Budget Satellite (ERBS)/Earth Radiation Budget Experiment (ERBE) Broadband Active Cavity Radiometer Sensors

    NASA Technical Reports Server (NTRS)

    Lee, Robert B., III; Smith, George L.; Wong, Takmeng

    2008-01-01

    From October 1984 through May 2005, the NASA Earth Radiation Budget Satellite (ERBS/ )/Earth Radiation Budget Experiment (ERBE)ERBE nonscanning active cavity radiometers (ACR) were used to monitor long-term changes in the earth radiation budget components of the incoming total solar irradiance (TSI), earth-reflected TSI, and earth-emitted outgoing longwave radiation (OLR). From September1984 through September 1999, using on-board calibration systems, the ERBS/ERBE ACR sensor response changes, in gains and offsets, were determined from on-orbit calibration sources and from direct observations of the incoming TSI through calibration solar ports at measurement precision levels approaching 0.5 W/sq m , at satellite altitudes. On October 6, 1999, the onboard radiometer calibration system elevation drive failed. Thereafter, special spacecraft maneuvers were performed to observe cold space and the sun in order to define the post-September 1999 geometry of the radiometer measurements, and to determine the October 1999-September 2003 ERBS sensor response changes. Analyses of these special solar and cold space observations indicate that the radiometers were pointing approximately 16 degrees away from the spacecraft nadir and on the anti-solar side of the spacecraft. The special observations indicated that the radiometers responses were stable at precision levels approaching 0.5 W/sq m . In this paper, the measurement geometry determinations and the determinations of the radiometers gain and offset are presented, which will permit the accurate processing of the October 1999 through September 2003 ERBE data products at satellite and top-of-the-atmosphere altitudes.

  12. Lessons Learned in the Livingstone 2 on Earth Observing One Flight Experiment

    NASA Technical Reports Server (NTRS)

    Hayden, Sandra C.; Sweet, Adam J.; Shulman, Seth

    2005-01-01

    The Livingstone 2 (L2) model-based diagnosis software is a reusable diagnostic tool for monitoring complex systems. In 2004, L2 was integrated with the JPL Autonomous Sciencecraft Experiment (ASE) and deployed on-board Goddard's Earth Observing One (EO-1) remote sensing satellite, to monitor and diagnose the EO-1 space science instruments and imaging sequence. This paper reports on lessons learned from this flight experiment. The goals for this experiment, including validation of minimum success criteria and of a series of diagnostic scenarios, have all been successfully net. Long-term operations in space are on-going, as a test of the maturity of the system, with L2 performance remaining flawless. L2 has demonstrated the ability to track the state of the system during nominal operations, detect simulated abnormalities in operations and isolate failures to their root cause fault. Specific advances demonstrated include diagnosis of ambiguity groups rather than a single fault candidate; hypothesis revision given new sensor evidence about the state of the system; and the capability to check for faults in a dynamic system without having to wait until the system is quiescent. The major benefits of this advanced health management technology are to increase mission duration and reliability through intelligent fault protection, and robust autonomous operations with reduced dependency on supervisory operations from Earth. The work-load for operators will be reduced by telemetry of processed state-of-health information rather than raw data. The long-term vision is that of making diagnosis available to the onboard planner or executive, allowing autonomy software to re-plan in order to work around known component failures. For a system that is expected to evolve substantially over its lifetime, as for the International Space Station, the model-based approach has definite advantages over rule-based expert systems and limit-checking fault protection systems, as these do not

  13. How to Communicate Near Earth Objects with the Public - Klet Observatory Experience

    NASA Astrophysics Data System (ADS)

    Ticha, Jana; Tichy, Milos; Kocer, Michal

    2015-08-01

    Near-Earth Object (NEO) research is counted among the most popular parts of communicating astronomy with the public. Increasing research results in the field of Near-Earth Objects as well as impact hazard investigations cause growing interest among general public and media. Furthermore NEO related issues have outstanding educational value. So thus communicating NEO detection, NEO characterization, possible impact effects, space missions to NEOs, ways of mitigation and impact warnings with the public and media belong to the most important tasks of scientists and research institutions.Our institution represents an unique liaison of the small professional research institution devoted especially to NEO studies (the Klet Observatory, Czech Republic) and the educational and public outreach branch (the Observatory and Planetarium Ceske Budejovice, Czech Republic). This all has been giving us an excellent opportunity for bringing NEO information to wider audience. We have been obtaining a wide experience in communicating NEOs with the public more than twenty years.There is a wide spectrum of public outreach tools aimed to NEO research and hazard. As the most useful ones we consider two special on-line magazines (e-zins) devoted to asteroids (www.planetky.cz) and comets (www.komety.cz) in Czech language, educational multimedia presentations for schools at different levels in planetarium, summer excursions for wide public just at the Klet Observatory on the top of the Klet mountain, public lectures, meetings and exhibitions. It seems to be very contributing and favoured by public to have opportunities for more or less informal meetings just with NEO researchers from time to time. Very important part of NEO public outreach consists of continuous contact with journalists and media including press releases, interviews, news, periodical programs. An increasing role of social media is taken into account through Facebook and Twitter profiles.The essential goal of all mentioned NEO

  14. Evaluation of the Earth Radiation Budget Experiment (ERBE) shortwave channel's stability using in-flight calibration sources

    NASA Technical Reports Server (NTRS)

    Gibson, Michael A.; Lee, Robert B., III; Thomas, Susan

    1992-01-01

    The Earth Radiation Budget Experiment (ERBE) radiometers were designed to make absolute measurements of the incoming solar, earth-reflected solar, and earth-emitted fluxes for investigations of the earth's climate system. Thermistor bolometers were the sensors used for the ERBE scanning radiometric package. Each thermistor bolometer package consisted of three narrow field of view broadband radiometric channels measuring shortwave, longwave, and total (0.2 micron to 50 microns) radiation. The in-flight calibration facilities include Mirror Attenuator Mosaics, shortwave internal calibration source, and internal blackbody sources to monitor the long-term responsivity of the radiometers. This paper describes the in-flight calibration facilities, the calibration data reduction techniques, and the results from the in-flight shortwave channel calibrations. The results indicate that the ERBE shortwave detectors were stable to within +/- 1 percent for up to five years of flight operation.

  15. Evaluation of the Earth Radiation Budget Experiment (ERBE) shortwave channel's stability using in-flight calibration sources

    NASA Technical Reports Server (NTRS)

    Gibson, Michael A.; Lee, Robert B., III; Thomas, Susan

    1992-01-01

    The Earth Radiation Budget Experiment (ERBE) radiometers were designed to make absolute measurements of the incoming solar, earth-reflected solar, and earth-emitted fluxes for investigations of the earth's climate system. Thermistor bolometers were the sensors used for the ERBE scanning radiometric package. Each thermistor bolometer package consisted of three narrow field of view broadband radiometric channels measuring shortwave, longwave, and total (0.2 micron to 50 microns) radiation. The in-flight calibration facilities include Mirror Attenuator Mosaics, shortwave internal calibration source, and internal blackbody sources to monitor the long-term responsivity of the radiometers. This paper describes the in-flight calibration facilities, the calibration data reduction techniques, and the results from the in-flight shortwave channel calibrations. The results indicate that the ERBE shortwave detectors were stable to within +/- 1 percent for up to five years of flight operation.

  16. Corneal hysteresis and its relevance to glaucoma

    PubMed Central

    Deol, Madhvi; Taylor, David A.; Radcliffe, Nathan M.

    2015-01-01

    Purpose of review Glaucoma is a leading cause of irreversible blindness worldwide. It is estimated that roughly 60.5 million people had glaucoma in 2010 and that this number is increasing. Many patients continue to lose vision despite apparent disease control according to traditional risk factors. The purpose of this review is to discuss the recent findings with regard to corneal hysteresis, a variable that is thought to be associated with the risk and progression of glaucoma. Recent findings Low corneal hysteresis is associated with optic nerve and visual field damage in glaucoma and the risk of structural and functional glaucoma progression. In addition, hysteresis may enhance intraocular pressure (IOP) interpretation: low corneal hysteresis is associated with a larger magnitude of IOP reduction following various glaucoma therapies. Corneal hysteresis is dynamic and may increase in eyes after IOP-lowering interventions are implemented. Summary It is widely accepted that central corneal thickness is a predictive factor for the risk of glaucoma progression. Recent evidence shows that corneal hysteresis also provides valuable information for several aspects of glaucoma management. In fact, corneal hysteresis may be more strongly associated with glaucoma presence, risk of progression, and effectiveness of glaucoma treatments than central corneal thickness. PMID:25611166

  17. Motion of liquid drops on surfaces induced by asymmetric vibration: role of contact angle hysteresis.

    PubMed

    Mettu, Srinivas; Chaudhury, Manoj K

    2011-08-16

    Hysteresis of wetting, like the Coulombic friction at solid/solid interface, impedes the motion of a liquid drop on a surface when subjected to an external field. Here, we present a counterintuitive example, where some amount of hysteresis enables a drop to move on a surface when it is subjected to a periodic but asymmetric vibration. Experiments show that a surface either with a negligible or high hysteresis is not conducive to any drop motion. Some finite hysteresis of contact angle is needed to break the periodic symmetry of the forcing function for the drift to occur. These experimental results are consistent with simulations, in which a drop is approximated as a linear harmonic oscillator. The experiment also sheds light on the effect of the drop size on flow reversal, where drops of different sizes move in opposite directions due to the difference in the phase of the oscillation of their center of mass.

  18. Understanding Coupled Earth-Surface Processes through Experiments and Models (Invited)

    NASA Astrophysics Data System (ADS)

    Overeem, I.; Kim, W.

    2013-12-01

    Traditionally, both numerical models and experiments have been purposefully designed to ';isolate' singular components or certain processes of a larger mountain to deep-ocean interconnected source-to-sink (S2S) transport system. Controlling factors driven by processes outside of the domain of immediate interest were treated and simplified as input or as boundary conditions. Increasingly, earth surface processes scientists appreciate feedbacks and explore these feedbacks with more dynamically coupled approaches to their experiments and models. Here, we discuss key concepts and recent advances made in coupled modeling and experimental setups. In addition, we emphasize challenges and new frontiers to coupled experiments. Experiments have highlighted the important role of self-organization; river and delta systems do not always need to be forced by external processes to change or develop characteristic morphologies. Similarly modeling f.e. has shown that intricate networks in tidal deltas are stable because of the interplay between river avulsions and the tidal current scouring with both processes being important to develop and maintain the dentritic networks. Both models and experiment have demonstrated that seemingly stable systems can be perturbed slightly and show dramatic responses. Source-to-sink models were developed for both the Fly River System in Papua New Guinea and the Waipaoa River in New Zealand. These models pointed to the importance of upstream-downstream effects and enforced our view of the S2S system as a signal transfer and dampening conveyor belt. Coupled modeling showed that deforestation had extreme effects on sediment fluxes draining from the catchment of the Waipaoa River in New Zealand, and that this increase in sediment production rapidly shifted the locus of offshore deposition. The challenge in designing coupled models and experiments is both technological as well as intellectual. Our community advances to make numerical model coupling more

  19. Research on the Dynamic Hysteresis Loop Model of the Residence Times Difference (RTD)-Fluxgate

    PubMed Central

    Wang, Yanzhang; Wu, Shujun; Zhou, Zhijian; Cheng, Defu; Pang, Na; Wan, Yunxia

    2013-01-01

    Based on the core hysteresis features, the RTD-fluxgate core, while working, is repeatedly saturated with excitation field. When the fluxgate simulates, the accurate characteristic model of the core may provide a precise simulation result. As the shape of the ideal hysteresis loop model is fixed, it cannot accurately reflect the actual dynamic changing rules of the hysteresis loop. In order to improve the fluxgate simulation accuracy, a dynamic hysteresis loop model containing the parameters which have actual physical meanings is proposed based on the changing rule of the permeability parameter when the fluxgate is working. Compared with the ideal hysteresis loop model, this model has considered the dynamic features of the hysteresis loop, which makes the simulation results closer to the actual output. In addition, other hysteresis loops of different magnetic materials can be explained utilizing the described model for an example of amorphous magnetic material in this manuscript. The model has been validated by the output response comparison between experiment results and fitting results using the model. PMID:24002230

  20. The Seasonal Soil Respiration-Temperature Hysteresis Relation Regulated by Photosynthesis and Soil Moisture

    NASA Astrophysics Data System (ADS)

    Zhang, Q.; Novick, K. A.; Phillips, R.; Manzoni, S.; Oishi, A. C.; Daly, E.; Scott, R. L.; Vargas, R.

    2016-12-01

    Soil respiration responds to temperature in an exponential manner across most ecosystems, but pronounced seasonal respiration-temperature hysteresis relations have been commonly reported in field measurements, with the underlying mechanisms remaining unclear. Our poor understanding to such hysteresis limits the ability to accurately simulate soil respiration. Here, we applied both numerical analysis and field measurements across various ecosystems, to identify the underlying mechanism. We used numerical model runs to show that both photosynthesis and soil moisture contribute to the formation of the hysteresis, supported by field measurements. A time lag between seasonal photosynthesis and soil temperature series plays an important role in decoupling soil respiration from temperature, providing one reason of the hysteresis. Specifically, the total soil respiration-temperature hysteresis is in clockwise direction when seasonal temperature lags behind photosynthesis, and in counterclockwise direction when photosynthesis lags behind soil temperature. Cross sites analysis shows that the time lag of respiration and temperature correlates linearly with that of photosynthesis and temperature (regression function: y=1.11x-2.35, R2=0.86, p<0.05). But when photosynthetic input to belowground is eliminated at a girdling experiment, no hysteresis emerge in the soil respiration-temperature relation, because the time lag of respiration and temperature is suppressed. In water limited ecosystem, soil moisture becomes the dominant factor of soil respiration so that the time lag between soil moisture and temperature provides another reason of the seasonal hysteresis.

  1. Research on the dynamic hysteresis loop model of the residence times difference (RTD)-fluxgate.

    PubMed

    Wang, Yanzhang; Wu, Shujun; Zhou, Zhijian; Cheng, Defu; Pang, Na; Wan, Yunxia

    2013-09-02

    Based on the core hysteresis features, the RTD-fluxgate core, while working, is repeatedly saturated with excitation field. When the fluxgate simulates, the accurate characteristic model of the core may provide a precise simulation result. As the shape of the ideal hysteresis loop model is fixed, it cannot accurately reflect the actual dynamic changing rules of the hysteresis loop. In order to improve the fluxgate simulation accuracy, a dynamic hysteresis loop model containing the parameters which have actual physical meanings is proposed based on the changing rule of the permeability parameter when the fluxgate is working. Compared with the ideal hysteresis loop model, this model has considered the dynamic features of the hysteresis loop, which makes the simulation results closer to the actual output. In addition, other hysteresis loops of different magnetic materials can be explained utilizing the described model for an example of amorphous magnetic material in this manuscript. The model has been validated by the output response comparison between experiment results and fitting results using the model.

  2. Evaluating Improvements to the Student Learning Experience in an Honours Earth and Environmental Sciences Program

    NASA Astrophysics Data System (ADS)

    Eyles, C. H.; Vajoczki, S.; Zobel, G.

    2002-12-01

    The School of Geography and Geology (SGG) at McMaster University recently received funding for a three-year project to apply new teaching strategies to enhance the undergraduate learning experience. A major focus of this project is to develop multiple opportunities for inquiry-based and experiential learning in the four-year Honours B.Sc program in Earth and Environmental Sciences. A second aim of the project is to enhance systematic personal transferable skills development in all students enrolled in this program. The aims of the SGG educational project are being met through progressive revision and refinement of instructional methodologies and the introduction of increased opportunities for experimental lab work, fieldwork, co-op and volunteer placements. Introductory level laboratory assignments are now up to 70% inquiry-based and fieldwork opportunities exist for all students within the program. A major hurdle to assessing the success of the project is evaluation of the effectiveness of the educational changes made in the programs. To date, a number of evaluation tools have been used to assess improvements to the learning experience including formative and summative student feedback (both informal and formal), student performance evaluations (pre- and post-course), and surveys of program alumni and potential employers. A system for the evaluation of personal transferable skills development is currently being developed using a skills attainment grid. By comparing future student attainment and feedback with that documented in a `baseline' survey carried out at the beginning of the project, it is hoped that assessment of improvements to the student learning experience can be made.

  3. Historical and idealized climate model experiments: an intercomparison of Earth system models of intermediate complexity

    NASA Astrophysics Data System (ADS)

    Eby, M.; Weaver, A. J.; Alexander, K.; Zickfeld, K.; Abe-Ouchi, A.; Cimatoribus, A. A.; Crespin, E.; Drijfhout, S. S.; Edwards, N. R.; Eliseev, A. V.; Feulner, G.; Fichefet, T.; Forest, C. E.; Goosse, H.; Holden, P. B.; Joos, F.; Kawamiya, M.; Kicklighter, D.; Kienert, H.; Matsumoto, K.; Mokhov, I. I.; Monier, E.; Olsen, S. M.; Pedersen, J. O. P.; Perrette, M.; Philippon-Berthier, G.; Ridgwell, A.; Schlosser, A.; Schneider von Deimling, T.; Shaffer, G.; Smith, R. S.; Spahni, R.; Sokolov, A. P.; Steinacher, M.; Tachiiri, K.; Tokos, K.; Yoshimori, M.; Zeng, N.; Zhao, F.

    2013-05-01

    Both historical and idealized climate model experiments are performed with a variety of Earth system models of intermediate complexity (EMICs) as part of a community contribution to the Intergovernmental Panel on Climate Change Fifth Assessment Report. Historical simulations start at 850 CE and continue through to 2005. The standard simulations include changes in forcing from solar luminosity, Earth's orbital configuration, CO2, additional greenhouse gases, land use, and sulphate and volcanic aerosols. In spite of very different modelled pre-industrial global surface air temperatures, overall 20th century trends in surface air temperature and carbon uptake are reasonably well simulated when compared to observed trends. Land carbon fluxes show much more variation between models than ocean carbon fluxes, and recent land fluxes appear to be slightly underestimated. It is possible that recent modelled climate trends or climate-carbon feedbacks are overestimated resulting in too much land carbon loss or that carbon uptake due to CO2 and/or nitrogen fertilization is underestimated. Several one thousand year long, idealized, 2 × and 4 × CO2 experiments are used to quantify standard model characteristics, including transient and equilibrium climate sensitivities, and climate-carbon feedbacks. The values from EMICs generally fall within the range given by general circulation models. Seven additional historical simulations, each including a single specified forcing, are used to assess the contributions of different climate forcings to the overall climate and carbon cycle response. The response of surface air temperature is the linear sum of the individual forcings, while the carbon cycle response shows a non-linear interaction between land-use change and CO2 forcings for some models. Finally, the preindustrial portions of the last millennium simulations are used to assess historical model carbon-climate feedbacks. Given the specified forcing, there is a tendency for the

  4. Hysteresis phenomenon of the field emission from carbon nanotube/polymer nanocomposite

    NASA Astrophysics Data System (ADS)

    Filippov, S. V.; Popov, E. O.; Kolosko, A. G.; Romanov, P. A.

    2015-11-01

    Using the high voltage scanning method and the technique of multichannel recording and processing of field emission (FE) characteristics in real time mode we found out some subtle effects on current voltage characteristics (IVC) of the multi-tip field emitters. We observed the direct and reverse hysteresis simultaneously in the same field emission experiment. Dependence of the form of IVC hysteresis on time of high voltage scanning was observed.

  5. Earth-satellite propagation above GHz: Papers from the 1972 spring URSI session on experiments utilizing the ATS-5 satellite

    NASA Technical Reports Server (NTRS)

    Ippolito, L. J. (Compiler)

    1972-01-01

    Papers are reported from the Special Session on Earth-Satellite Propagation Above 10 GHz, presented at The 1972 Spring Meeting of the United States National Committee, International Union of Radio Science, April 1972, Washington, D. C. This session was devoted to propagation measurements associated with the Applications Technology Satellite (ATS-5), which provided the first operational earth-space links at frequencies above 15 GHz. A comprehensive summary is presented of the major results of the ATS-5 experiment measurements and related radiometric, radar and meteorological studies. The papers are organized around seven selected areas of interest, with the results of the various investigators combined into a single paper presented by a principal author for that area. A comprehensive report is provided on the results of the ATS-5 satellite to earth transmissions. A complete list of published reports and presentations related to the ATS-5 Millimeter Wave Experiment is included.

  6. Hysteresis during contact angles measurement.

    PubMed

    Diaz, M Elena; Fuentes, Javier; Cerro, Ramon L; Savage, Michael D

    2010-03-15

    A theory, based on the presence of an adsorbed film in the vicinity of the triple contact line, provides a molecular interpretation of intrinsic hysteresis during the measurement of static contact angles. Static contact angles are measured by placing a sessile drop on top of a flat solid surface. If the solid surface has not been previously in contact with a vapor phase saturated with the molecules of the liquid phase, the solid surface is free of adsorbed liquid molecules. In the absence of an adsorbed film, molecular forces configure an advancing contact angle larger than the static contact angle. After some time, due to an evaporation/adsorption process, the interface of the drop coexists with an adsorbed film of liquid molecules as part of the equilibrium configuration, denoted as the static contact angle. This equilibrium configuration is metastable because the droplet has a larger vapor pressure than the surrounding flat film. As the drop evaporates, the vapor/liquid interface contracts and the apparent contact line moves towards the center of the drop. During this process, the film left behind is thicker than the adsorbed film and molecular attraction results in a receding contact angle, smaller than the equilibrium contact angle. 2009 Elsevier Inc. All rights reserved.

  7. Conditions necessary for capillary hysteresis in porous media: Tests of grain-size and surface tension influences

    SciTech Connect

    Tokunaga, Tetsu K.; Olson, Keith R.; Wan, Jiamin

    2004-03-12

    Hysteresis in the relation between water saturation and matric potential is generally regarded as a basic aspect of unsaturated porous media. However, the nature of an upper length scale limit for saturation hysteresis has not been previously addressed. Since hysteresis depends on whether or not capillary rise occurs at the grain scale, this criterion was used to predict required combinations of grain size, surface tension, fluid-fluid density differences, and acceleration in monodisperse systems. The Haines number (Ha), composed of the aforementioned variables, is proposed as a dimensionless number useful for separating hysteretic (Ha < 15) versus nonhysteretic (Ha > 15) behavior. Vanishing of hysteresis was predicted to occur for grain sizes greater than 10.4 +- 0.5 mm, for water-air systems under the acceleration of ordinary gravity, based on Miller-Miller scaling and Haines' original model for hysteresis. Disappearance of hysteresis was tested through measurements of drainage and wetting curves of sands and gravels and occurs between grain sizes of 10 and 14 mm (standard conditions). The influence of surface tension was tested through measurements of moisture retention in 7 mm gravel, without and with a surfactant (sodium dodecylbenzenesulfonate (SDBS)). The ordinary water system (Ha = 7) exhibited hysteresis, while the SDBS system (Ha = 18) did not. The experiments completed in this study indicate that hysteresis in moisture retention relations has an upper limit at Ha = 16 +- 2 and show that hysteresis is not a fundamental feature of unsaturated porous media.

  8. Partitioning of potassium between silicates and sulphide melts - Experiments relevant to the earth's core.

    NASA Technical Reports Server (NTRS)

    Goettel, K. A.

    1972-01-01

    The partitioning of potassium between roedderite, K2Mg5Si12O30 and an Fe-FeS melt was investigated at temperatures about 40 C above the Fe-FeS eutectic. Roedderite was considered a prime candidate for one of the potassium-bearing phases in the primitive earth because roedderite and merrihueite are the only two silicates containing essential potassium which have been identified in stony meteorites. Application of the results to a primitive chondritic earth is discussed, and it is concluded that extraction of most of the earth's potassium into the Fe-FeS core would occur under the conditions in the early earth.-

  9. The origin of the double-triangle hysteresis loops in ErFeO3 near the low temperature erbium ordering transition

    NASA Astrophysics Data System (ADS)

    Tsymbal, L. T.; Bazaliy, Ya. B.; Kakazei, G. N.

    2009-03-01

    Magnetic properties of an orthoferrite ErFeO3 are determined by the iron and the rare-earth magnetic ions. Interactions between magnetic sub-systems of ErFeO3 lead to a sequence of orientation phase transitions observed in this material. In this work hysteresis loops in single crystal ErFeO3 samples were studied below the spin-rotation transition region, T < 80 K. Above and around the compensation point Tcomp= 46 K the hysteresis loops are rectangular, with the coercive force diverging at Tcomp. As the temperature is lowered towards the erbium ordering transition TN2= 4.1 K, the shape of the loops experiences a dramatic change. At 20 K the loops develop triangular ``tails.'' At 10 K the triangles become prominent while the central rectangular part near H = 0 collapses. A double-loop hysteresis pattern with two triangular loops emerges. We explain this behavior by a domain wall motion reversal mechanism with negligible pinning of the walls in the sample. The transition from the rectangular to the double-triangle loops is due to the competition between the energy barrier of wall nucleation and the demagnetization energy gain achieved by placing the wall inside the sample. Our model explains well the correlation of the loop's shapes and sizes with the total magnetization of ErFeO3.

  10. Understanding rheological hysteresis in soft glassy materials.

    PubMed

    Radhakrishnan, Rangarajan; Divoux, Thibaut; Manneville, Sébastien; Fielding, Suzanne M

    2017-03-01

    Motivated by recent experimental studies of rheological hysteresis in soft glassy materials, we study numerically strain rate sweeps in simple yield stress fluids and viscosity bifurcating yield stress fluids. Our simulations of downward followed by upward strain rate sweeps, performed within fluidity models and the soft glassy rheology model, successfully capture the experimentally observed monotonic decrease of the area of the rheological hysteresis loop with sweep time in simple yield stress fluids, and the bell shaped dependence of hysteresis loop area on sweep time in viscosity bifurcating fluids. We provide arguments explaining these two different functional forms in terms of differing tendencies of simple and viscosity bifurcating fluids to form shear bands during the sweeps, and show that the banding behaviour captured by our simulations indeed agrees with that reported experimentally. We also discuss the difference in hysteresis behaviour between inelastic and viscoelastic fluids. Our simulations qualitatively agree with the experimental data discussed here for four different soft glassy materials.

  11. Hysteresis behavior of the binary Ising model

    NASA Astrophysics Data System (ADS)

    Akıncı, Ümit; Karakoyun, Gülşen

    2017-09-01

    Hysteresis behaviors of the binary alloy system represented by the formula AcB1-c have been investigated within the framework of EFT. The system consists of type A atoms (spin-1) with concentration c and type B atoms (spin-1/2) with concentration 1 - c . After giving the phase diagrams, we focused on the different type of hysteresis behaviors in the system. Especially, the mechanisms giving rise to double hysteresis behavior have been explained, which appear at large negative values of the crystal field and low temperatures. It has been observed that binary alloy system could exhibit DH behavior in region 0 < c < 0.557 . Besides, dependence of hysteresis loop area, coercive field and remanent magnetization on the concentration has been investigated.

  12. Spatial autocorrelation of radiation measured by the Earth Radiation Budget Experiment: Scene inhomogeneity and reciprocity violation

    SciTech Connect

    Davies, R.

    1994-10-01

    The spatial autocorrelation functions of broad-band longwave and shortwave radiances measured by the Earth Radiation Budget Experiment (ERBE) are analyzed as a function of view angle in an investigation of the general effects of scene inhomogeneity on radiation. For nadir views, the correlation distance of the autocorrelation function is about 900 km for longwave radiance and about 500 km for shortwave radiance, consistent with higher degrees of freedom in shortwave reflection. Both functions rise monotonically with view angle, but there is a substantial difference in the relative angular dependence of the shortwave and longwave functions, especially for view angles less than 50 deg. In this range, the increase with angle of the longwave functions is found to depend only on the expansion of pixel area with angle, whereas the shortwave functions show an additional dependence on angle that is attributed to the occlusion of inhomogeneities by cloud height variations. Beyond a view angle of about 50 deg, both longwave and shortwave functions appear to be affected by cloud sides. The shortwave autocorrelation functions do not satisfy the principle of directional reciprocity, thereby proving that the average scene is horizontally inhomogeneous over the scale of an ERBE pixel (1500 sq km). Coarse stratification of the measurements by cloud amount, however, indicates that the average cloud-free scene does satisfy directional reciprocity on this scale.

  13. Spatial autocorrelation of radiation measured by the Earth Radiation Budget Experiment: Scene inhomogeneity and reciprocity violation

    NASA Technical Reports Server (NTRS)

    Davies, Roger

    1994-01-01

    The spatial autocorrelation functions of broad-band longwave and shortwave radiances measured by the Earth Radiation Budget Experiment (ERBE) are analyzed as a function of view angle in an investigation of the general effects of scene inhomogeneity on radiation. For nadir views, the correlation distance of the autocorrelation function is about 900 km for longwave radiance and about 500 km for shortwave radiance, consistent with higher degrees of freedom in shortwave reflection. Both functions rise monotonically with view angle, but there is a substantial difference in the relative angular dependence of the shortwave and longwave functions, especially for view angles less than 50 deg. In this range, the increase with angle of the longwave functions is found to depend only on the expansion of pixel area with angle, whereas the shortwave functions show an additional dependence on angle that is attributed to the occlusion of inhomogeneities by cloud height variations. Beyond a view angle of about 50 deg, both longwave and shortwave functions appear to be affected by cloud sides. The shortwave autocorrelation functions do not satisfy the principle of directional reciprocity, thereby proving that the average scene is horizontally inhomogeneous over the scale of an ERBE pixel (1500 sq km). Coarse stratification of the measurements by cloud amount, however, indicates that the average cloud-free scene does satisfy directional reciprocity on this scale.

  14. Comparison of Longwave Diurnal Models Applied to Simulations of the Earth Radiation Budget Experiment.

    NASA Astrophysics Data System (ADS)

    Brooks, David R.; Minnis, Patrick

    1984-01-01

    Simulations of the Earth Radiation Budget Experiment with several satellite sampling schemes have been used to compare three different approaches to modeling longwave diurnal behavior observed over certain kinds of land regions. November 1978 data from the GOES satellite have been used to produce a reference set of radiation parameters over the regions of interest. The monthly average longwave radiant exitance has been estimated first with linear interpolation between satellite measurements, then with a method that replaces linear interpolations across day-night boundaries with piecewise constant extrapolations to the boundaries, and finally with a trigonometric model which replaces some of the linear interpolations that go through daytime measurements over land. This third model consists of constant extrapolation of nighttime measurements to sunrise or sunset, with a half-sine curve fitted through existing daytime measurements and constrained at sunrise and sunset to an average of the surrounding nighttime measurements. It applies only when the daytime and surrounding nighttime measurements meet certain restrictive criteria, including tests that tend to limit the trigonometric model to cloud-free regions. For all satellite sampling strategies considered, the trigonometric model gave the best overall monthly estimate of longwave radiant exitance. For non-land regions, the linear interpolation model generally gave better results than the piecewise constant model.

  15. An enhanced analysis of increasing-resolution coupled seasonal prediction experiments with EC-EARTH 3

    NASA Astrophysics Data System (ADS)

    Andreu-Burillo, Isabel; Batté, Lauriane; Asif, Muhammad; Doblas-Reyes, Francisco

    2014-05-01

    With a focus on the ocean component, we use the EC-Earth coupled model to investigate the forecast quality of a set of ensemble seasonal predictions with different spatial resolutions in the atmospheric and oceanic components. Starting from relatively standard atmosphere and ocean model grid-sizes, we examine the impact of increasing resolutions to values rarely attained in global climate forecast systems, like 40 km in the atmospheric component and 25 km in the ocean component. In order to take into account atmospheric model uncertainties we introduce random Gaussian perturbations to the wind, temperature and humidity tendencies in the IFS atmospheric model, following the Stochastically Perturbed Parameterization Tendencies scheme developed at ECMWF (SPPT). Although no perturbations are made in the lower levels of the atmospheric model, SPPT stochastic perturbations have an impact on the mean state of surface variables such as SST and surface winds. Here, we examine the differences of a set of experiments with standard resolution, high resolution of the ocean/atmosphere component, and the combination of these with SPPT schemes. The outcome of a standard set of forecast quality measures is enhanced by a three-dimensional scan of some key features of the ocean, taking into account the change with forecast time.

  16. Closed-cell foams produced from sputter-deposited aluminum. [experiments on earth and in space environment

    NASA Technical Reports Server (NTRS)

    Patten, J. W.; Greenwell, E. N.

    1977-01-01

    Sputter deposited aluminum containing argon was melted to produce foam, both in the earth's gravitational field and in a zero-gravity space environment. Experiments leading to trapping of up to 270 ppm argon sputtering gas in pure aluminum during high-rate dc triode sputter deposition are discussed. Conduct of the melting experiments and design of the furnace used are described. Metallography; an analysis of bubble size, distribution, and morphology; and a preliminary description of the kinetics are also presented.

  17. Closed-cell foams produced from sputter-deposited aluminum. [experiments on earth and in space environment

    NASA Technical Reports Server (NTRS)

    Patten, J. W.; Greenwell, E. N.

    1977-01-01

    Sputter deposited aluminum containing argon was melted to produce foam, both in the earth's gravitational field and in a zero-gravity space environment. Experiments leading to trapping of up to 270 ppm argon sputtering gas in pure aluminum during high-rate dc triode sputter deposition are discussed. Conduct of the melting experiments and design of the furnace used are described. Metallography; an analysis of bubble size, distribution, and morphology; and a preliminary description of the kinetics are also presented.

  18. Structural hysteresis model of transmitting mechanical systems

    NASA Astrophysics Data System (ADS)

    Ruderman, M.; Bertram, T.

    2015-02-01

    We present a structural hysteresis model which describes the dynamic behavior of transmitting mechanical systems with a hysteretic spring and damped bedstop element, both connected in series. From the application point view this approach can be used for predicting the transmitted mechanical force based only on the known kinematic excitation. Using the case study of an elastic gear transmission we show and identify a hysteresis response which multivariate behavior depends on an internal state of the bedstop motion.

  19. Equivalent Circuit Modeling of Hysteresis Motors

    SciTech Connect

    Nitao, J J; Scharlemann, E T; Kirkendall, B A

    2009-08-31

    We performed a literature review and found that many equivalent circuit models of hysteresis motors in use today are incorrect. The model by Miyairi and Kataoka (1965) is the correct one. We extended the model by transforming it to quadrature coordinates, amenable to circuit or digital simulation. 'Hunting' is an oscillatory phenomenon often observed in hysteresis motors. While several works have attempted to model the phenomenon with some partial success, we present a new complete model that predicts hunting from first principles.

  20. Contact angle hysteresis at the nanometer scale.

    PubMed

    Delmas, Mathieu; Monthioux, Marc; Ondarçuhu, Thierry

    2011-04-01

    Using atomic force microscopy with nonconventional carbon tips, the pinning of a liquid contact line on individual nanometric defects was studied. This mechanism is responsible for the occurrence of the contact angle hysteresis. The presence of weak defects which do not contribute to the hysteresis is evidenced for the first time. The dissipated energy associated with strong defects is also measured down to values in the range of kT, which correspond to defect sizes in the order of 1 nm.

  1. Investigation of Strategies to Promote Effective Teacher Professional Development Experiences in Earth Science

    ERIC Educational Resources Information Center

    Engelmann, Carol A.

    2014-01-01

    This dissertation serves as a call to geoscientists to share responsibility with K-12 educators for increasing Earth science literacy. When partnerships are created among K-12 educators and geoscientists, the synergy created can promote Earth science literacy in students, teachers, and the broader community. The research described here resulted in…

  2. Earth Sciences as a Vehicle for Gifted Education--The Hong Kong Experience

    ERIC Educational Resources Information Center

    Murphy, Phillip J.; Chan, Lung Sang; Murphy, Elizabeth

    2012-01-01

    The development and delivery of an Earth-science-focused short course designed to prepare Hong Kong students for university level study is described. Earth sciences provide an inspirational and challenging context for learning and teaching in Hong Kong's increasingly skills-based curriculum. (Contains 3 figures and 4 online resources.)

  3. Earth Sciences as a Vehicle for Gifted Education--The Hong Kong Experience

    ERIC Educational Resources Information Center

    Murphy, Phillip J.; Chan, Lung Sang; Murphy, Elizabeth

    2012-01-01

    The development and delivery of an Earth-science-focused short course designed to prepare Hong Kong students for university level study is described. Earth sciences provide an inspirational and challenging context for learning and teaching in Hong Kong's increasingly skills-based curriculum. (Contains 3 figures and 4 online resources.)

  4. Analysis of earth albedo effect on sun sensor measurements based on theoretical model and mission experience

    NASA Technical Reports Server (NTRS)

    Brasoveanu, Dan; Sedlak, Joseph

    1998-01-01

    Analysis of flight data from previous missions indicates that anomalous Sun sensor readings could be caused by Earth albedo interference. A previous Sun sensor study presented a detailed mathematical model of this effect. The model can be used to study the effect of both diffusive and specular reflections and to improve Sun angle determination based on perturbed Sun sensor measurements, satellite position, and an approximate knowledge of attitude. The model predicts that diffuse reflected light can cause errors of up to 10 degrees in Coarse Sun Sensor (CSS) measurements and 5 to 10 arc sec in Fine Sun Sensor (FSS) measurements, depending on spacecraft orbit and attitude. The accuracy of these sensors is affected as long as part of the illuminated Earth surface is present in the sensor field of view. Digital Sun Sensors (DSS) respond in a different manner to the Earth albedo interference. Most of the time DSS measurements are not affected, but for brief periods of time the Earth albedo can cause errors which are a multiple of the sensor least significant bit and may exceed one degree. This paper compares model predictions with Tropical Rainfall Measuring Mission (TRMM) CSS measurements in order to validate and refine the model. Methods of reducing and mitigating the impact of Earth albedo are discussed. ne CSS sensor errors are roughly proportional to the Earth albedo coefficient. Photocells that are sensitive only to ultraviolet emissions would reduce the effective Earth albedo by up to a thousand times, virtually eliminating all errors caused by Earth albedo interference.

  5. Investigation of Strategies to Promote Effective Teacher Professional Development Experiences in Earth Science

    ERIC Educational Resources Information Center

    Engelmann, Carol A.

    2014-01-01

    This dissertation serves as a call to geoscientists to share responsibility with K-12 educators for increasing Earth science literacy. When partnerships are created among K-12 educators and geoscientists, the synergy created can promote Earth science literacy in students, teachers, and the broader community. The research described here resulted in…

  6. The centennial of the Sagnac experiment in the optical regime: From a tabletop experiment to the variation of the Earth's rotation

    NASA Astrophysics Data System (ADS)

    Schreiber, Karl Ulrich; Gebauer, André; Igel, Heiner; Wassermann, Joachim; Hurst, Robert B.; Wells, Jon-Paul R.

    2014-12-01

    The investigation of non-reciprocal behavior of optical beams in a rotating reference frame was the main motivation of the historic tabletop experiment of George Sagnac. His ground-breaking experiment was extended to a very large installation more than a decade later, which was sensitive enough to allow Michelson, Pearson and Gale to resolve the rotation rate of the Earth by an optical interferometer. With the advent of lasers in the early sixties of the last century, rotating laser cavities with a ring structure demonstrated superior performance and very soon matured to a point where mechanical gyroscopes were quickly superseded by laser gyroscopes in aircraft navigation. When vastly upscaled ring lasers were taken back to the laboratory at the end of the 20th century, the goal of applying the Sagnac effect to geodesy for the monitoring of tiny variations of Earth's rotation was the main motivation. The large-ring laser G, which is the most stable instrument out of a series of instruments built by the New Zealand-German collaboration, routinely resolves the rotation rate of the Earth to better than eight orders of magnitude. Since G is directly referenced to the Earth rotation axis, the effect of diurnal polar motion, the Chandler and the Annual wobbles as well as tilts from the solid Earth tides can be found in the interferogram obtained from the ring laser. G has also demonstrated high sensitivity to rotations associated with seismic events. The toroidal eigenmodes of the Earth when they are excited by large earthquakes have been resolved. A surprisingly large amplitude has been measured for Love wave signals contained in the microseismic background signal. This paper summarizes the recent development of highly sensitive large Sagnac gyroscopes, and presents unique results from the measurements of rotations of the earth. xml:lang="fr"

  7. ESA takes part in Earth observation and space science experiments on board the Space Shuttle

    NASA Astrophysics Data System (ADS)

    1993-03-01

    The ATLAS-2 mission is focusing on Earth observation and space science; three out of the seven instruments have been developed by scientific institutes in Belgium, France and Germany, with support from ESA. Four experiments have been provided by NASA and US scientists. The three European instruments have already shown an excellent performance during the first Atlas mission in March 1992, when they were tended by payload specialist Dirk Frimout, a Belgian astronaut and ESA staff member. Although the main scientific objective of the series of Atlas missions is to achieve continuity of annual measurements over a period as long as a decade, the first scientific results from Atlas can already be considered as a contribution to critical research topics, in particular the environment. The data from ATLAS-2 will add to this achievement. Two European instruments, Solcon and Solspec, are measuring to a very high degree of precision the total irradiation the Earth receives from the Sun - the "solar constant" -and the spectral distribution of this radiation over a wide range of wavelengths. Knowledge of the solar constant and the solar radiation spectrum matters not only for a better understanding of the Sun, but also for improving numerical models of climate and climate change. SOLCON was developed under the responsibility of Dr. Dominique Crommelynck of the Royal Meteorological Institute of Brussels, Belgium. SOLSPEC was instead developed under the responsibility of Dr. Gerard Thuillier of the CNRS, Verrieres le Buisson, France. One of these instruments will be fully remote-controlled by scientists from a laboratory in Belgium, via telecommunications links to the Shuttle, and the data of another will be transmitted to Belgium in real time to follow the results obtained. This approach is known as telescience: using telescience, a scientist can monitor his experiment in real-time, repeat it with different settings, consult his team, process data and adapt his measurements when

  8. PanEurasian Experiment (PEEX): Modelling Platform for Earth System Observations and Forecasting

    NASA Astrophysics Data System (ADS)

    Baklanov, Alexander; Mahura, Alexander; Penenko, Vladimir; Zilitinkevich, Sergej; Kulmala, Markku

    2014-05-01

    models, analysing scenarios, inverse modelling, modelling based on measurement needs and processes; • Model validation by remote sensing data and assimilation of satellite observations to constrain models to better understand processes, e.g., emissions and fluxes with top-down modelling; • Geophysical/ chemical model validation with experiments at various spatial and temporal scales. Added value of the comprehensive multi-platform observations and modeling; network of monitoring stations with the capacity to quantify those interactions between neighboring areas ranging from the Arctic and the Mediterranean to the Chinese industrial areas and the Asian steppes is needed. For example, apart from development of Russian stations in the PEEX area a strong co-operation with surrounding research infrastructures in the model of ACTRIS network needs to be established in order to obtain a global perspective of the emissions transport, transformation and ageing of pollutants incoming and exiting the PEEX area. The PEEX-MP aims to simulate and predict the physical aspects of the Earth system and to improve understanding of the bio-geochemical cycles in the PEEX domain, and beyond. The environmental change in this region implies that, from the point-of-view of atmospheric flow, the lower boundary conditions are changing. This is important for applications with immediate relevance for society, such as numerical weather prediction. The PEEX infrastructure will provide a unique view to the physical properties of the Earth surface, which can be used to improve assessment and prediction models. This will directly benefit citizens of the North in terms of better early warning of hazardous events, for instance. On longer time-scales, models of the bio-geochemical cycles in the PEEX domain absolutely need support from the new monitoring infra-structure to better measure and quantify soil and vegetation properties. In the most basic setup, the atmospheric and oceanic Global Circulation

  9. Providing Authentic Research Experiences for Pre-Service Teachers through UNH's Transforming Earth System Science Education (TESSE) Program

    NASA Astrophysics Data System (ADS)

    Varner, R. K.; Furman, T.; Porter, W.; Darwish, A.; Graham, K.; Bryce, J.; Brown, D.; Finkel, L.; Froburg, E.; Guertin, L.; Hale, S. R.; Johnson, J.; von Damm, K.

    2007-12-01

    The University of New Hampshire's Transforming Earth System Science Education (UNH TESSE) project is designed to enrich the education and professional development of in-service and pre-service teachers, who teach or will teach Earth science curricula. As part of this program, pre-service teachers participated in an eight- week summer Research Immersion Experience (RIE). The main goal of the RIE is to provide authentic research experiences in Earth system science for teachers early in their careers in an effort to increase future teachers` comfort and confidence in bringing research endeavors to their students. Moreover, authentic research experiences for teachers will complement teachers` efforts to enhance inquiry-based instruction in their own classrooms. Eighteen pre-service teachers associated with our four participating institutions - Dillard University (4), Elizabeth City State University (4), Pennsylvania State University (5), and University of New Hampshire (UNH) (5) participated in the research immersion experience. Pre-service teachers were matched with a faculty mentor who advised their independent research activities. Each pre-service teacher was expected to collect and analyze his or her own data to address their research question. Some example topics researched by participants included: processes governing barrier island formation, comparison of formation and track of hurricanes Hugo and Katrina, environmental consequences of Katrina, numerical models of meander formation, climatic impacts on the growth of wetland plants, and the visual estimation of hydrothermal vent properties. Participants culminated their research experience with a public presentation to an audience of scientists and inservice teachers.

  10. The World's Largest Experiment Manipulating Solar Energy Input To Earth Resumed In 2003

    NASA Astrophysics Data System (ADS)

    Ward, P. L.

    2010-12-01

    Small amounts of solar-ultraviolet-energy absorbing gases such as ozone, SO2, and NO2 play an unusually large role warming the atmosphere. A mere 3 to 8 ppmv ozone at elevations of 15 to 50 km and associated exothermic chemical reactions warm the atmosphere >50oC, forming the stratosphere. All three molecules have an asymmetric top shape that, unlike linear molecules of CO2, forms a permanent electromagnetic dipole enhancing interaction with electromagnetic radiation. Planck’s postulate (Energy = a constant times frequency) implies that solar ultraviolet energy strongly absorbed by SO2 is 43 times greater than infrared energy radiated by earth and strongly absorbed by CO2. Solar energy in the blue visible spectrum and ultraviolet causes electronic transitions and an absorption spectrum that is a continuum, absorbing far more energy per unit gas than spectral line absorption of infrared energy caused by rotational and vibrational transitions. Absorption of electromagnetic energy by atmospheric gases increases rapidly with increasing frequency, an observation not accounted for by the use of specific heat in atmospheric models to link energy flux with temperature. While SO2 in the stratosphere is oxidized to a sulfuric acid aerosol that reflects sunlight, cooling the earth, SO2 in the troposphere is oxidized much more slowly than commonly assumed. Well-documented concentrations of tens of ppbv SO2 emitted by humans burning fossil fuels, especially coal, in northern mid-latitudes are contemporaneous, with suitable time delays for warming the ocean, with increased global warming during the 20th century, greatest by nearly a factor of two in the northern hemisphere. A decrease by 18% of anthropogenic SO2 emissions between 1979 and 2000 aimed at reducing acid rain had the unintended effect of reducing the global mean rate of temperature increase to zero by 1998. By 2003, global SO2 emissions began to rise sharply due to the rapid increase in number of new coal

  11. A novel model of magnetorheological damper with hysteresis division

    NASA Astrophysics Data System (ADS)

    Yu, Jianqiang; Dong, Xiaomin; Zhang, Zonglun

    2017-10-01

    Due to the complex nonlinearity of magnetorheological (MR) behavior, the modeling of MR dampers is a challenge. A simple and effective model of MR damper remains a work in progress. A novel model of MR damper is proposed with force-velocity hysteresis division method in this study. A typical hysteresis loop of MR damper can be simply divided into two novel curves with the division idea. One is the backbone curve and the other is the branch curve. The exponential-family functions which capturing the characteristics of the two curves can simplify the model and improve the identification efficiency. To illustrate and validate the novel phenomenological model with hysteresis division idea, a dual-end MR damper is designed and tested. Based on the experimental data, the characteristics of the novel curves are investigated. To simplify the parameters identification and obtain the reversibility, the maximum force part, the non-dimensional backbone part and the non-dimensional branch part are derived from the two curves. The maximum force part and the non-dimensional part are in multiplication type add-rule. The maximum force part is dependent on the current and maximum velocity. The non-dominated sorting genetic algorithm II (NSGA II) based on the design of experiments (DOE) is employed to identify the parameters of the normalized shape functions. Comparative analysis is conducted based on the identification results. The analysis shows that the novel model with few identification parameters has higher accuracy and better predictive ability.

  12. Measuring the Value of Earth Observation Information with the Gravity Research and Climate Experiment (GRACE) Satellite

    NASA Astrophysics Data System (ADS)

    Bernknopf, R.; Kuwayama, Y.; Brookshire, D.; Macauley, M.; Zaitchik, B.; Pesko, S.; Vail, P.

    2014-12-01

    Determining how much to invest in earth observation technology depends in part on the value of information (VOI) that can be derived from the observations. We design a framework and then evaluate the value-in-use of the NASA Gravity Research and Climate Experiment (GRACE) for regional water use and reliability in the presence of drought. As a technology that allows measurement of water storage, the GRACE Data Assimilation System (DAS) provides information that is qualitatively different from that generated by other water data sources. It provides a global, reproducible grid of changes in surface and subsurface water resources on a frequent and regular basis. Major damages from recent events such as the 2012 Midwest drought and the ongoing drought in California motivate the need to understand the VOI from remotely sensed data such as that derived from GRACE DAS. Our conceptual framework models a dynamic risk management problem in agriculture. We base the framework on information from stakeholders and subject experts. The economic case for GRACE DAS involves providing better water availability information. In the model, individuals have a "willingness to pay" (wtp) for GRACE DAS - essentially, wtp is an expression of savings in reduced agricultural input costs and for costs that are influenced by regional policy decisions. Our hypothesis is that improvements in decision making can be achieved with GRACE DAS measurements of water storage relative to data collected from groundwater monitoring wells and soil moisture monitors that would be relied on in the absence of GRACE DAS. The VOI is estimated as a comparison of outcomes. The California wine grape industry has features that allow it to be a good case study and a basis for extrapolation to other economic sectors. We model water use in this sector as a sequential decision highlighting the attributes of GRACE DAS input as information for within-season production decisions as well as for longer-term water reliability.

  13. Long-Term Soil Experiments: A Key to Managing Earth's Rapidly Changing Critical Zones

    NASA Astrophysics Data System (ADS)

    Richter, D., Jr.

    2014-12-01

    In a few decades, managers of Earth's Critical Zones (biota, humans, land, and water) will be challenged to double food and fiber production and diminish adverse effects of management on the wider environment. To meet these challenges, an array of scientific approaches is being used to increase understanding of Critical Zone functioning and evolution, and one amongst these approaches needs to be long-term soil field studies to move us beyond black boxing the belowground Critical Zone, i.e., to further understanding of processes driving changes in the soil environment. Long-term soil experiments (LTSEs) provide direct observations of soil change and functioning across time scales of decades, data critical for biological, biogeochemical, and environmental assessments of sustainability; for predictions of soil fertility, productivity, and soil-environment interactions; and for developing models at a wide range of temporal and spatial scales. Unfortunately, LTSEs globally are not in a good state, and they take years to mature, are vulnerable to loss, and even today remain to be fully inventoried. Of the 250 LTSEs in a web-based network, results demonstrate that soils and belowground Critical Zones are highly dynamic and responsive to human management. The objective of this study is to review the contemporary state of LTSEs and consider how they contribute to three open questions: (1) can soils sustain a doubling of food production in the coming decades without further impinging on the wider environment, (2) how do soils interact with the global C cycle, and (3) how can soil management establish greater control over nutrient cycling. While LTSEs produce significant data and perspectives for all three questions, there is on-going need and opportunity for reviews of the long-term soil-research base, for establishment of an efficiently run network of LTSEs aimed at sustainability and improving management control over C and nutrient cycling, and for research teams that

  14. The Third Tibetan Plateau Atmospheric Scientific Experiment for Understanding the Earth-Atmosphere Coupled System

    NASA Astrophysics Data System (ADS)

    Zhao, P.; Xu, X.; Chen, F.; Guo, X.; Zheng, X.; Liu, L. P.; Hong, Y.; Li, Y.; La, Z.; Peng, H.; Zhong, L. Z.; Ma, Y.; Tang, S. H.; Liu, Y.; Liu, H.; Li, Y. H.; Zhang, Q.; Hu, Z.; Sun, J. H.; Zhang, S.; Dong, L.; Zhang, H.; Zhao, Y.; Yan, X.; Xiao, A.; Wan, W.; Zhou, X.

    2016-12-01

    The Third Tibetan Plateau atmospheric scientific experiment (TIPEX-III) was initiated jointly by the China Meteorological Administration, the National Natural Scientific Foundation, and the Chinese Academy of Sciences. This paper presents the background, scientific objectives, and overall experimental design of TIPEX-III. It was designed to conduct an integrated observation of the earth-atmosphere coupled system over the Tibetan Plateau (TP) from land surface, planetary boundary layer (PBL), troposphere, and stratosphere for eight to ten years by coordinating ground- and air-based measurement facilities for understanding spatial heterogeneities of complex land-air interactions, cloud-precipitation physical processes, and interactions between troposphere and stratosphere. TIPEX-III originally began in 2014, and is ongoing. It established multiscale land-surface and PBL observation networks over the TP and a tropospheric meteorological radiosonde network over the western TP, and executed an integrated observation mission for cloud-precipitation physical features using ground-based radar systems and aircraft campaigns and an observation task for atmospheric ozone, aerosol, and water vapor. The archive, management, and share policy of the observation data are also introduced herein. Some TIPEX-III data have been preliminarily applied to analyze the features of surface sensible and latent heat fluxes, cloud-precipitation physical processes, and atmospheric water vapor and ozone over the TP, and to improve the local precipitation forecast. Furthermore, TIPEX-III intends to promote greater scientific and technological cooperation with international research communities and broader organizations. Scientists working internationally are invited to participate in the field campaigns and to use the TIPEX-III data for their own research.

  15. Cadmium sorption onto Natural Red Earth - An assessment using batch experiments and surface complexation modeling

    NASA Astrophysics Data System (ADS)

    Mahatantila, K.; Minoru, O.; Seike, Y.; Vithanage, M. S.

    2010-12-01

    Natural red earth (NRE), an iron coated sand found in north western part of Sri Lanka was used to examine its retention behavior of cadmium, a heavy metal postulated as a factor of chronic kidney disease in Sri Lanka. Adsorption studies were examined in batch experiments as a function of pH, ionic strength and initial cadmium loading. Proton binding sites on NRE were characterized by potentiometric titration yielding a pHzpc around 6.6. The cadmium adsorption increased from 6% to 99% along with a pH increase from 4 to 8.5. In addition, the maximum adsorption was observed when pH is greater than 7.5. Ionic strength dependency of cadmium adsorption for 100 fold variation of NaNO3 evidences the dominance of an inner-sphere bonding mechanism for 10 fold variation of initial cadmium loadings (4.44 and 44.4 µmol/L). Adsorption edges were quantified with a 2pK generalized diffuse double layer model considering two site types, >FeOH and >AlOH, for Cd2+ binding. From modeling, we introduced a monodentate chemical bonding mechanism for cadmium binding on to NRE and this finding was further verified with FTIR spectroscopy. Intrinsic constants determined were log KFeOCd = 8.543 and log KAlOCd = 13.917. Isotherm data implies the heterogeneity of NRE surface and the sorption maximum of 9.418 x10-6 mol/g and 1.3x10-4 mol/g for Langmuir and Freundlich isotherm models. The study suggested the potential of NRE as a material in decontaminating environmental water polluted with cadmium.

  16. Optimal trajectories for the Aeroassisted Flight Experiment. Part 1: Equations of motion in an Earth-fixed system

    NASA Technical Reports Server (NTRS)

    Miele, A.; Zhao, Z. G.; Lee, W. Y.

    1989-01-01

    The determination of optimal trajectories for the aeroassisted flight experiment (AFE) is discussed. The AFE refers to the study of the free flight of an autonomous spacecraft, shuttle-launched and shuttle-recovered. Its purpose is to gather atmospheric entry environmental data for use in designing aeroassisted orbital transfer vehicles (AOTV). It is assumed that: (1) the spacecraft is a particle of constant mass; (2) the Earth is rotating with constant angular velocity; (3) the Earth is an oblate planet, and the gravitational potential depends on both the radial distance and the latitude (harmonics of order higher than four are ignored); and (4) the atmosphere is at rest with respect to the Earth. Under these assumptions, the equations of motion for hypervelocity atmospheric flight (which can be used not only for AFE problems, but also for AOT problems and space shuttle problems) are derived in an Earth-fixed system. Transformation relations are supplied which allow one to pass from quantities computed in an Earth-fixed system to quantities computed in an inertial system, and vice versa.

  17. Analysis of radiation parameters derived from the multisatellite Earth Radiation Budget Experiment

    NASA Technical Reports Server (NTRS)

    Gibson, G. G.; Denn, F. M.; Young, D. F.; Harrison, E. F.; Minnis, P.; Barkstrom, B. R.; Wielicki, B. A.

    1990-01-01

    To quantify the diurnal radiative heating and cooling cycles of the earth and the atmosphere, data from instruments on the Earth Radiation Budget Satellite (ERBS) spacecraft and NOAA-9 satellites obtained from February 1985 through January 1986 were used to investigate longwave (LW) and shortwave (SW) flux as well as albedo for each month of the year. Seasonal variations of radiative parameters and their diurnal cycles are examined for the deserts, vegetated land, and oceans over the globe. The results show significant seasonal variations in both the outgoing LW and the absorbed SW flux, and a pronounced difference was found between oceanic and continental surfaces. Over much of the globe, LW warming is balanced by SW cooling, and clouds have a net cooling effect on the earth. Many areas of the earth were found to exhibit significant diurnal variations in both the LW flux and albedo.

  18. Rare Earth Element Partition Coefficients from Enstatite/Melt Synthesis Experiments

    NASA Technical Reports Server (NTRS)

    Schwandt, Craig S.; McKay, Gordon A.

    1997-01-01

    Enstatite (En(80)Fs(19)Wo(01)) was synthesized from a hypersthene normative basaltic melt doped at the same time with La, Ce, Nd, Sm, Eu, Dy, Er, Yb and Lu. The rare earth element concentrations were measured in both the basaltic glass and the enstatite. Rare earth element concentrations in the glass were determined by electron microprobe analysis with uncertainties less than two percent relative. Rare earth element concentrations in enstatite were determined by secondary ion mass spectrometry with uncertainties less than five percent relative. The resulting rare earth element partition signature for enstatite is similar to previous calculated and composite low-Ca pigeonite signatures, but is better defined and differs in several details. The partition coefficients are consistent with crystal structural constraints.

  19. Analysis of radiation parameters derived from the multisatellite Earth Radiation Budget Experiment

    NASA Technical Reports Server (NTRS)

    Gibson, G. G.; Denn, F. M.; Young, D. F.; Harrison, E. F.; Minnis, P.; Barkstrom, B. R.; Wielicki, B. A.

    1990-01-01

    To quantify the diurnal radiative heating and cooling cycles of the earth and the atmosphere, data from instruments on the Earth Radiation Budget Satellite (ERBS) spacecraft and NOAA-9 satellites obtained from February 1985 through January 1986 were used to investigate longwave (LW) and shortwave (SW) flux as well as albedo for each month of the year. Seasonal variations of radiative parameters and their diurnal cycles are examined for the deserts, vegetated land, and oceans over the globe. The results show significant seasonal variations in both the outgoing LW and the absorbed SW flux, and a pronounced difference was found between oceanic and continental surfaces. Over much of the globe, LW warming is balanced by SW cooling, and clouds have a net cooling effect on the earth. Many areas of the earth were found to exhibit significant diurnal variations in both the LW flux and albedo.

  20. Laboratory experiments on the impact disruption of iron meteorites at temperature of near-Earth space

    NASA Astrophysics Data System (ADS)

    Katsura, Takekuni; Nakamura, Akiko M.; Takabe, Ayana; Okamoto, Takaya; Sangen, Kazuyoshi; Hasegawa, Sunao; Liu, Xun; Mashimo, Tsutomu

    2014-10-01

    Iron meteorites and some M-class asteroids are generally understood to be fragments that were originally part of cores of differentiated planetesimals or part of local melt pools on primitive bodies. The parent bodies of iron meteorites may have formed in the terrestrial planet region, from which they were then scattered into the main belt (Bottke, W.F., Nesvorný, D., Grimm, R.E., Morbidelli, A., O'Brien, D.P. [2006]. Nature 439, 821-824). Therefore, a wide range of collisional events at different mass scales, temperatures, and impact velocities would have occurred between the time when the iron was segregated and the impact that eventually exposed the iron meteorites to interplanetary space. In this study, we performed impact disruption experiments of iron meteorite specimens as projectiles or targets at room temperature to increase understanding of the disruption process of iron bodies in near-Earth space. Our iron specimens (as projectiles or targets) were almost all smaller in size than their counterparts (as targets or projectiles, respectively). Experiments of impacts of steel specimens were also conducted for comparison. The fragment mass distribution of the iron material was different from that of rocks. In the iron fragmentation, a higher percentage of the mass was concentrated in larger fragments, probably due to the ductile nature of the material at room temperature. The largest fragment mass fraction f was dependent not only on the energy density but also on the size d of the specimen. We assumed a power-law dependence of the largest fragment mass fraction to initial peak pressure P0 normalized by a dynamic strength, Y, which was defined to be dependent on the size of the iron material. A least squares fit to the data of iron meteorite specimens resulted in the following relationship: f∝∝d, indicating a large size dependence of f. Additionally, the deformation of the iron materials in high-velocity shots was found to be most significant when the

  1. Adsorption hysteresis in ink-bottle pore

    NASA Astrophysics Data System (ADS)

    Morishige, Kunimitsu; Tateishi, Noriko

    2003-07-01

    To examine the mechanism of the adsorption hysteresis in ink-bottle pores, we measured the temperature dependence of the adsorption-desorption isotherms of argon, oxygen, and carbon dioxide onto SBA-16 ordered mesoporous material with cagelike pores. The hysteresis loop always shrank with increasing temperature and eventually disappeared at a hysteresis temperature (Th), well below the bulk critical temperature (Tc). When the relative pressures p/p0 of the capillary condensation and evaporation are plotted as a function of reduced temperature T/Tc, all the data including the transition pressures for nitrogen reported previously are represented by a common curve. We also calculated the temperature dependence of the capillary condensation and evaporation pressures of nitrogen under the assumption that adsorption and desorption in an ink-bottle pore may be regarded as the process of the disappearance and formation of a gas bubble in a liquid droplet confined to the pore. A fit between the observed and calculated transition pressures in a wide temperature range was reasonable in light of several assumptions and approximations used. This clearly indicates that the energy barrier for the formation and disappearance of vapor bubbles in the liquid confined to the pores is responsible for the appearance of the adsorption hysteresis and the hysteresis temperature is not concerned with the so-called capillary criticality. At temperatures higher than Th, the reversible capillary condensation takes place, because the energy barrier between a full liquid pore and the vapor coexisting with the liquid film becomes surmountable.

  2. Contact angle hysteresis, adhesion, and marine biofouling.

    PubMed

    Schmidt, Donald L; Brady, Robert F; Lam, Karen; Schmidt, Dale C; Chaudhury, Manoj K

    2004-03-30

    Adhesive and marine biofouling release properties of coatings containing surface-oriented perfluoroalkyl groups were investigated. These coatings were prepared by cross-linking a copolymer of 1H,1H,2H,2H-heptadecafluorodecyl acrylate and acrylic acid with a copolymer of poly(2-isopropenyl-2-oxazoline) and methyl methacrylate at different molar ratios. The relationships between contact angle, contact angle hysteresis, adhesion, and marine biofouling were studied. Adhesion was determined by peel tests using pressure-sensitive adhesives. The chemical nature of the surfaces was studied by using X-ray photoelectron spectroscopy. Resistance to marine biofouling of an optimized coating was studied by immersion in seawater and compared to previous, less optimized coatings. The adhesive release properties of the coatings did not correlate well with the surface energies of the coatings estimated from the static and advancing contact angles nor with the amount of fluorine present on the surface. The adhesive properties of the surfaces, however, show a correlation with water receding contact angles and contact angle hysteresis (or wetting hysteresis) resulting from surface penetration and surface reconstruction. Coatings having the best release properties had both the highest cross-link density and the lowest contact angle hysteresis. An optimized coating exhibited unprecedented resistance to marine biofouling. Water contact angle hysteresis appears to correlate with marine biofouling resistance.

  3. Mesoscopic magnetomechanical hysteresis in a magnetorheological elastomer

    NASA Astrophysics Data System (ADS)

    Biller, A. M.; Stolbov, O. V.; Raikher, Yu. L.

    2015-08-01

    Field-induced magnetostatic interaction in a pair of identical particles made of a magnetically soft ferromagnet is studied. It is shown that due to saturation of the ferromagnet magnetization, this case differs significantly from the (super)paramagnetic one. A numerical solution is given, discussed, and compared with that provided by a simpler model (nonlinear mutual dipoles). We show that for multidomain ferromagnetic particles embedded in an elastomer matrix, as for paramagnetic ones in the same environment, pair clusters may form or break by a hysteresis scenario. However, the magnetization saturation brings in important features to this effect. First, the bistability state and the hysteresis take place only in a limited region of the material parameters of the system. Second, along with the hysteresis jumps occurring under the sole influence of the field, the "latent" hysteresis is possible which realizes only if the action of the field is combined with some additional (nonmagnetic) external factor. The obtained conditions, when used to assess the possibility of clustering in real magnetorheological polymers, infer an important role of mesoscopic magnetomechanical hysteresis for the macroscopic properties of these composites.

  4. Mesoscopic magnetomechanical hysteresis in a magnetorheological elastomer.

    PubMed

    Biller, A M; Stolbov, O V; Raikher, Yu L

    2015-08-01

    Field-induced magnetostatic interaction in a pair of identical particles made of a magnetically soft ferromagnet is studied. It is shown that due to saturation of the ferromagnet magnetization, this case differs significantly from the (super)paramagnetic one. A numerical solution is given, discussed, and compared with that provided by a simpler model (nonlinear mutual dipoles). We show that for multidomain ferromagnetic particles embedded in an elastomer matrix, as for paramagnetic ones in the same environment, pair clusters may form or break by a hysteresis scenario. However, the magnetization saturation brings in important features to this effect. First, the bistability state and the hysteresis take place only in a limited region of the material parameters of the system. Second, along with the hysteresis jumps occurring under the sole influence of the field, the "latent" hysteresis is possible which realizes only if the action of the field is combined with some additional (nonmagnetic) external factor. The obtained conditions, when used to assess the possibility of clustering in real magnetorheological polymers, infer an important role of mesoscopic magnetomechanical hysteresis for the macroscopic properties of these composites.

  5. Hysteresis from Multiscale Porosity: Modeling Water Sorption and Shrinkage in Cement Paste

    NASA Astrophysics Data System (ADS)

    Pinson, Matthew B.; Masoero, Enrico; Bonnaud, Patrick A.; Manzano, Hegoi; Ji, Qing; Yip, Sidney; Thomas, Jeffrey J.; Bazant, Martin Z.; Van Vliet, Krystyn J.; Jennings, Hamlin M.

    2015-06-01

    Cement paste has a complex distribution of pores and molecular-scale spaces. This distribution controls the hysteresis of water sorption isotherms and associated bulk dimensional changes (shrinkage). We focus on two locations of evaporable water within the fine structure of pastes, each having unique properties, and we present applied physics models that capture the hysteresis by dividing drying and rewetting into two related regimes based on relative humidity (RH). We show that a continuum model, incorporating a pore-blocking mechanism for desorption and equilibrium thermodynamics for adsorption, explains well the sorption hysteresis for a paste that remains above approximately 20% RH. In addition, we show with molecular models and experiments that water in spaces of ≲1 nm width evaporates below approximately 20% RH but reenters throughout the entire RH range. This water is responsible for a drying shrinkage hysteresis similar to that of clays but opposite in direction to typical mesoporous glass. Combining the models of these two regimes allows the entire drying and rewetting hysteresis to be reproduced accurately and provides parameters to predict the corresponding dimensional changes. The resulting model can improve the engineering predictions of long-term drying shrinkage accounting also for the history dependence of strain induced by hysteresis. Alternative strategies for quantitative analyses of the microstructure of cement paste based on this mesoscale physical model of water content within porous spaces are discussed.

  6. The effect of contact angle hysteresis on droplet coalescence and mixing.

    PubMed

    Nilsson, Michael A; Rothstein, Jonathan P

    2011-11-15

    In this work, droplet coalescence and the subsequent mixing in superhydrophobic surfaces is studied over a range of impact velocities and impact angles. Sanded Teflon surfaces are used as a novel two-dimensional microfluidics platform. These superhydrophobic surfaces exhibit a constant advancing contact angle of θ(A)=150° over a broad range of contact angle hysteresis. As a result, the effect of contact angle hysteresis on droplet coalescence and mixing can be studied. Based on the observed characteristics of coalescence, three different regimes of coalescence are identified as a function of both Weber number and impact angle. These regimes include oscillation dominated, rotation dominated, and mixed dynamics. It is shown that within Weber number ranges achievable in this experiment, hysteresis greatly reduces the deformation of the droplet coalescence process and the subsequent mixing. In head-on collisions, higher hysteresis is found to decrease the frequency at which the resulting dr oscillates. In the case of glancing collisions, where the resulting droplet is found to rotate, higher hysteresis increases the rate of rotation although the overall angular momentum is found to be independent of contact angle hysteresis.

  7. Hysteresis Effects and Strain-Induced Homogeneity Effects in Base Metal Thermocouples

    NASA Astrophysics Data System (ADS)

    Pavlasek, P.; Elliott, C. J.; Pearce, J. V.; Duris, S.; Palencar, R.; Koval, M.; Machin, G.

    2015-03-01

    Thermocouples are used in a wide variety of industrial applications in which they play an important role for temperature control and monitoring. Wire inhomogeneity and hysteresis effects are major sources of uncertainty in thermocouple measurements. To efficiently mitigate these effects, it is first necessary to explore the impact of strain-induced inhomogeneities and hysteresis, and their contribution to the uncertainty. This article investigates homogeneity and hysteresis effects in Types N and K mineral-insulated metal-sheathed (MIMS) thermocouples. Homogeneity of thermocouple wires is known to change when mechanical strain is experienced by the thermoelements. To test this influence, bends of increasingly small radii, typical in industrial applications, were made to a number of thermocouples with different sheath diameters. The change in homogeneity was determined through controlled immersion of the thermocouple into an isothermal liquid oil bath at and was found to be very small at for Type K thermocouples, with no measureable change in Type N thermocouples found. An experiment to determine the hysteresis effect in thermocouples was performed on swaged, MIMS Type N and Type K thermocouples, in the temperature range from to . The hysteresis measurements presented simulate the conditions that thermocouples may be exposed to in industrial applications through continuous cycling over 136 h. During this exposure, a characteristic drift from the reference function has been observed but no considerable difference between the heating and cooling measurements was measureable. The measured differences were within the measurement uncertainties; therefore, no hysteresis was observed.

  8. Mercury Porosimetry: Contact Angle Hysteresis of Materials with Controlled Pore Structure.

    PubMed

    Salmas, Constantinos; Androutsopoulos, George

    2001-07-01

    Mercury Porosimetry (MP) hysteresis is a commonly observed phenomenon in which mercury retention disguises further the overall hysteresis picture. This article introduces a new interpretation of the MP hysteresis based on the combined effect of pore structure networking and mercury contact angle variation occurring between the mercury penetration and retraction operations. To distinguish the contribution of each factor the following investigations were carried out. Nitrogen sorption (NP) and MP experiments were performed on samples of an anodic aluminum membrane and the results were interpreted in terms of the Corrugated Pore Structure Model (CPSM), i.e., CPSM-Nitrogen and CPSM-Mercury models, respectively. The simulation of the observed hysteresis data using the CPSM model enabled the evaluation of an identical for the two methods intrinsic pore size distribution (PSD) and cumulative surface area in perfect agreement with the respective BET value. Additionally, the CPSM analysis of data resulted in the evaluation of mercury contact angles, i.e., θ(p)=143 degrees and θ(r)=101.7 degrees for the MP penetration and retraction branches of the hysteresis loop, respectively. Moreover, CPSM-Mercury simulations of literature MP hysteresis data, valid for controlled-pore glasses and nuclepore membranes, led to the evaluation of contact angles, i.e., glasses: θ(p)=143 degrees, θ(r)=100.5-107.5 degrees and nuclepore: θ(p)=143 degrees, θ(r)=118- 121 degrees. The latter values are comparable with relevant literature data and approximate those determined for the anodic aluminum membrane. The CPSM model employed herein proved to be a flexible and reliable model for simulating the pertinent hysteresis loops by combining pore networking and contact angle hysteresis phenomena. Copyright 2001 Academic Press.

  9. Contrasting diel hysteresis between soil autotrophic and heterotrophic respiration in a desert ecosystem under different rainfall scenarios.

    PubMed

    Song, Weimin; Chen, Shiping; Zhou, Yadan; Wu, Bo; Zhu, Yajuan; Lu, Qi; Lin, Guanghui

    2015-11-30

    Diel hysteresis occurs often between soil CO2 efflux (R(S)) and temperature, yet, little is known if diel hysteresis occurs in the two components of R(S), i.e., autotrophic respiration (R(A)) and heterotrophic respiration (R(H)), and how diel hysteresis will respond to future rainfall change. We conducted a field experiment in a desert ecosystem in northern China simulating five different scenarios of future rain regimes. Diel variations of soil CO2 efflux and soil temperature were measured on Day 6 and Day 16 following the rain addition treatments each month during the growing season. We found contrasting responses in the diel hysteresis of R(A) and R(H) to soil temperature, with a clockwise hysteresis loop for R(H) but a counter-clockwise hysteresis loop for R(A). Rain addition significantly increased the magnitude of diel hysteresis for both R(H) and R(A) on Day 6, but had no influence on either on Day 16 when soil moisture was much lower. These findings underline the different roles of biological (i.e. plant and microbial activities) and physical-chemical (e.g. heat transport and inorganic CO2 exchange) processes in regulating the diel hysteresis of R(A) and R(H), which should be considered when estimating soil CO2 efflux in desert regions under future rainfall regime.

  10. Contrasting diel hysteresis between soil autotrophic and heterotrophic respiration in a desert ecosystem under different rainfall scenarios

    PubMed Central

    Song, Weimin; Chen, Shiping; Zhou, Yadan; Wu, Bo; Zhu, Yajuan; Lu, Qi; Lin, Guanghui

    2015-01-01

    Diel hysteresis occurs often between soil CO2 efflux (RS) and temperature, yet, little is known if diel hysteresis occurs in the two components of RS, i.e., autotrophic respiration (RA) and heterotrophic respiration (RH), and how diel hysteresis will respond to future rainfall change. We conducted a field experiment in a desert ecosystem in northern China simulating five different scenarios of future rain regimes. Diel variations of soil CO2 efflux and soil temperature were measured on Day 6 and Day 16 following the rain addition treatments each month during the growing season. We found contrasting responses in the diel hysteresis of RA and RH to soil temperature, with a clockwise hysteresis loop for RH but a counter-clockwise hysteresis loop for RA. Rain addition significantly increased the magnitude of diel hysteresis for both RH and RA on Day 6, but had no influence on either on Day 16 when soil moisture was much lower. These findings underline the different roles of biological (i.e. plant and microbial activities) and physical-chemical (e.g. heat transport and inorganic CO2 exchange) processes in regulating the diel hysteresis of RA and RH, which should be considered when estimating soil CO2 efflux in desert regions under future rainfall regime. PMID:26615895

  11. Earth Observing System (EOS) Aqua Launch and Early Mission Attitude Support Experiences

    NASA Technical Reports Server (NTRS)

    Tracewell, D.; Glickman, J.; Hashmall, J.; Natanson, G.; Sedlak, J.

    2003-01-01

    The Earth Observing System (EOS) Aqua satellite was successfully launched on May 4,2002. Aqua is the second in the series of EOS satellites. EOS is part of NASA s Earth Science Enterprise Program, whose goals are to advance the scientific understanding of the Earth system. Aqua is a three-axis stabilized, Earth-pointing spacecraft in a nearly circular, sun-synchronous orbit at an altitude of 705 km. The Goddard Space Flight Center (GSFC) Flight Dynamics attitude team supported all phases of the launch and early mission. This paper presents the main results and lessons learned during this period, including: real-time attitude mode transition support, sensor calibration, onboard computer attitude validation, response to spacecraft emergencies, postlaunch attitude analyses, and anomaly resolution. In particular, Flight Dynamics support proved to be invaluable for successful Earth acquisition, fine-point mode transition, and recognition and correction of several anomalies, including support for the resolution of problems observed with the MODIS instrument.

  12. The effect of the low Earth orbit environment on space solar cells: Results of the Advanced Photovoltaic Experiment (S0014)

    NASA Technical Reports Server (NTRS)

    Brinker, David J.; Hickey, John R.; Scheiman, David A.

    1993-01-01

    The results of post-flight performance testing of the solar cells flown on the Advanced Photovoltaic Experiment are reported. Comparison of post-flight current-voltage characteristics with similar pre-flight data revealed little or no change in solar cell conversion efficiency, confirming the reliability and endurance of space photovoltaic cells. This finding is in agreement with the lack of significant physical changes in the solar cells despite nearly six years in the low Earth orbit environment.

  13. Comparison of general circulation models to Earth Radiation Budget Experiment data - Computation of clear-sky fluxes

    NASA Technical Reports Server (NTRS)

    Cess, Robert D.; Potter, Gerald L.; Gates, W. L.; Morcrette, Jean-Jacques; Corsetti, Lisa

    1992-01-01

    A clear-sky flux computation method is described which is representative of the Earth Radiation Budget Experiment data processing, while at the same time being enough straightforward for implementation in a general circulation model (GCM). The method is a hybrid version of Cess and Potter (1987) Method I and Method II clear-sky top-of-the-atmosphere flux computations for GCMs. The procedure is demonstrated using the ECMWF GCM.

  14. Piloting a Global Collaborative Experiment to Determine your Place on the Planet and the Circumference of the Earth

    NASA Astrophysics Data System (ADS)

    Solie, D. J.; Paniwozik, R. L.; Wallace, P.

    2012-12-01

    As part of the laboratory component in Bush Physics for the 21st Century, a distance delivered physics course geared toward rural and Indigenous students in Alaska, students determine their village location on earth from simple sun angle measurements at local-noon during the spring equinox. Students measure the length of the sun shadow cast by a rod mounted on a horizontal surface, over short time intervals on or near the spring equinox during mid-day. Local-noon occurs when the sun is the highest and its corresponding shadow the shortest. Local noon, when expressed in Universal Time, can be directly converted to the local longitude in degrees. Local latitude in degrees, is obtained from the local-noon shadow length on the spring equinox and simple trigonometry. As an added bonus, using data from different sites, students can collaborate to approximate the circumference of the earth from their measurements. In the spirit of Eratosthenes, students envision an earth-sized pie wedge cut from a polar great-circle where the curve of the wedge on the earth's surface is the North-South distance between two often road-less sites (determined using Google Earth, a map or a globe), and the angle of the wedge is the difference between the site latitudes. The earth's circumference is calculated from this wedge. In 2012 with the aim of including Indigenous groups from other regions of the planet, we expanded this experiment to include teams from Japan, Puerto Rico, American Samoa, and New Zealand. We present our results from this pilot year.

  15. Anomalous Hysteresis in Perovskite Solar Cells.

    PubMed

    Snaith, Henry J; Abate, Antonio; Ball, James M; Eperon, Giles E; Leijtens, Tomas; Noel, Nakita K; Stranks, Samuel D; Wang, Jacob Tse-Wei; Wojciechowski, Konrad; Zhang, Wei

    2014-05-01

    Perovskite solar cells have rapidly risen to the forefront of emerging photovoltaic technologies, exhibiting rapidly rising efficiencies. This is likely to continue to rise, but in the development of these solar cells there are unusual characteristics that have arisen, specifically an anomalous hysteresis in the current-voltage curves. We identify this phenomenon and show some examples of factors that make the hysteresis more or less extreme. We also demonstrate stabilized power output under working conditions and suggest that this is a useful parameter to present, alongside the current-voltage scan derived power conversion efficiency. We hypothesize three possible origins of the effect and discuss its implications on device efficiency and future research directions. Understanding and resolving the hysteresis is essential for further progress and is likely to lead to a further step improvement in performance.

  16. A thermodynamic model of contact angle hysteresis

    NASA Astrophysics Data System (ADS)

    Makkonen, Lasse

    2017-08-01

    When a three-phase contact line moves along a solid surface, the contact angle no longer corresponds to the static equilibrium angle but is larger when the liquid is advancing and smaller when the liquid is receding. The difference between the advancing and receding contact angles, i.e., the contact angle hysteresis, is of paramount importance in wetting and capillarity. For example, it determines the magnitude of the external force that is required to make a drop slide on a solid surface. Until now, fundamental origin of the contact angle hysteresis has been controversial. Here, this origin is revealed and a quantitative theory is derived. The theory is corroborated by the available experimental data for a large number of solid-liquid combinations. The theory is applied in modelling the contact angle hysteresis on a textured surface, and these results are also in quantitative agreement with the experimental data.

  17. Magnetomechanical damping and magnetoelastic hysteresis in permalloy

    NASA Astrophysics Data System (ADS)

    Ercuta, A.; Mihalca, I.

    2002-11-01

    The inverse Wiedemann effect (IWE) consisting in longitudinal magnetization reversals was detected with a cylindrical permalloy layer subjected to circular DC magnetic fields while performing low frequency (~1 Hz) free torsion oscillations. Hysteresis occurring in the magnetization vs elastic strain dependence (the `magnetoelastic hysteresis') suggested irreversible processes activated mechanically. Joint vibration and magnetization time records were carried out by means of an experimental set-up including inverted pendulum and conventional integrating fluxmeter, in order to compare the relative energy losses ascribed to the magnetomechanical damping (MMD) and to the magnetoelastic hysteresis, respectively. The experimental results clearly pointed out a close connection between IWE and MMD providing evidence that, when simultaneously examined, both effects reflect the same basic phenomenon: the irreversible magnetization changes induced by the elastic strain.

  18. A thermodynamic model of contact angle hysteresis.

    PubMed

    Makkonen, Lasse

    2017-08-14

    When a three-phase contact line moves along a solid surface, the contact angle no longer corresponds to the static equilibrium angle but is larger when the liquid is advancing and smaller when the liquid is receding. The difference between the advancing and receding contact angles, i.e., the contact angle hysteresis, is of paramount importance in wetting and capillarity. For example, it determines the magnitude of the external force that is required to make a drop slide on a solid surface. Until now, fundamental origin of the contact angle hysteresis has been controversial. Here, this origin is revealed and a quantitative theory is derived. The theory is corroborated by the available experimental data for a large number of solid-liquid combinations. The theory is applied in modelling the contact angle hysteresis on a textured surface, and these results are also in quantitative agreement with the experimental data.

  19. Validation of clear-sky fluxes for tropical oceans from the Earth Radiation Budget Experiment

    NASA Technical Reports Server (NTRS)

    Collins, W. D.; Inamdar, A. K.

    1995-01-01

    The existence and magnitude of a systematic bias in the clear-sky longwave fluxes from the Earth Radiation Budget Experiment (ERBE) is investigated. The bias is apparently introduced because the ERBE method for scene identification does not account for large zonal gradients in longwave absorption by water vapor. The ERBE fluxes are compared to fluxes calculated with a radiative transfer model from ship radiosonde measurements. The comparison is based upon an analysis of 5 yr of coincident satellite and radiosonde observations for equatorial ocean regions. The differences between the ERBE and model fluxes are examined as functions of sea surface temperature (SST) and relative humidity. The authors use height-mean relative humidity bar-RH as an index of atmospheric moisture. The average offset between and model ERBE fluxes ranges between +2 and +6 W/sq m for SSTs above 295 K, and the gradients with respect to SST are nearly identical. However, the difference between the model and ERBE depends significantly on the tropospheric relative humidity. ERBE fluxes exceed model fluxes for bar-RH above 70%, and the maximum offset of +9 to +12 W/sq m is consistent with previous estimates. There are also indications that the clear-sky fluxes for bar-RH below 25% may be underestimated by about 10-15 W/sq m. Since extreme values of height-mean humidity are relatively infrequent, the net bias introduced in the ERBE monthly mean clear-sky fluxes is generally less than the systematic error in estimates introduced in the ERBE monthly mean clear-sky fluxes is generally less than the systematic error in estimates of the instantaneous fluxes. These findings support earlier work on the coupling between SST and the atmospheric greenhouse effect, in particular the existence of a super greenhouse effect for oceans warmer than 300 K. Recent reports of much larger systematic differences are not supported by this analysis. The results indicate that comparison of general circulation model (GCM

  20. Validation of clear-sky fluxes for tropical oceans from the Earth Radiation Budget Experiment

    NASA Technical Reports Server (NTRS)

    Collins, W. D.; Inamdar, A. K.

    1995-01-01

    The existence and magnitude of a systematic bias in the clear-sky longwave fluxes from the Earth Radiation Budget Experiment (ERBE) is investigated. The bias is apparently introduced because the ERBE method for scene identification does not account for large zonal gradients in longwave absorption by water vapor. The ERBE fluxes are compared to fluxes calculated with a radiative transfer model from ship radiosonde measurements. The comparison is based upon an analysis of 5 yr of coincident satellite and radiosonde observations for equatorial ocean regions. The differences between the ERBE and model fluxes are examined as functions of sea surface temperature (SST) and relative humidity. The authors use height-mean relative humidity bar-RH as an index of atmospheric moisture. The average offset between and model ERBE fluxes ranges between +2 and +6 W/sq m for SSTs above 295 K, and the gradients with respect to SST are nearly identical. However, the difference between the model and ERBE depends significantly on the tropospheric relative humidity. ERBE fluxes exceed model fluxes for bar-RH above 70%, and the maximum offset of +9 to +12 W/sq m is consistent with previous estimates. There are also indications that the clear-sky fluxes for bar-RH below 25% may be underestimated by about 10-15 W/sq m. Since extreme values of height-mean humidity are relatively infrequent, the net bias introduced in the ERBE monthly mean clear-sky fluxes is generally less than the systematic error in estimates introduced in the ERBE monthly mean clear-sky fluxes is generally less than the systematic error in estimates of the instantaneous fluxes. These findings support earlier work on the coupling between SST and the atmospheric greenhouse effect, in particular the existence of a super greenhouse effect for oceans warmer than 300 K. Recent reports of much larger systematic differences are not supported by this analysis. The results indicate that comparison of general circulation model (GCM

  1. Hysteresis compensation technique for POF curvature sensors

    NASA Astrophysics Data System (ADS)

    Leal, Arnaldo G.; Frizera, Anselmo; Pontes, Maria José

    2017-04-01

    Polymer optical fibers (POF) have higher strain limits, fracture toughness and flexibility in bend if compared to glass optical fibers. These characteristics enable the application of POFs as curvature sensors. However, the polymer is a viscoelastic material, which does not have a constant response with stress or strain. For this reason, a curvature sensor based on POF may present high hysteresis. This paper proposes a dynamic compensation technique based on the angular velocity of the sensor. Results show a hysteresis up to 10 times lower. Furthermore, it results on a simple calibration equation, which can be applied in real-time measurements.

  2. Hysteresis modeling in graphene field effect transistors

    SciTech Connect

    Winters, M.; Rorsman, N.; Sveinbjörnsson, E. Ö.

    2015-02-21

    Graphene field effect transistors with an Al{sub 2}O{sub 3} gate dielectric are fabricated on H-intercalated bilayer graphene grown on semi-insulating 4H-SiC by chemical vapour deposition. DC measurements of the gate voltage v{sub g} versus the drain current i{sub d} reveal a severe hysteresis of clockwise orientation. A capacitive model is used to derive the relationship between the applied gate voltage and the Fermi energy. The electron transport equations are then used to calculate the drain current for a given applied gate voltage. The hysteresis in measured data is then modeled via a modified Preisach kernel.

  3. Application of geometry based hysteresis modelling in compensation of hysteresis of piezo bender actuator

    NASA Astrophysics Data System (ADS)

    Milecki, Andrzej; Pelic, Marcin

    2016-10-01

    This paper presents results of studies of an application of a new method of piezo bender actuators modelling. A special hysteresis simulation model was developed and is presented. The model is based on a geometrical deformation of main hysteresis loop. The piezoelectric effect is described and the history of the hysteresis modelling is briefly reviewed. Firstly, a simple model for main loop modelling is proposed. Then, a geometrical description of the non-saturated hysteresis is presented and its modelling method is introduced. The modelling makes use of the function describing the geometrical shape of the two hysteresis main curves, which can be defined theoretically or obtained by measurement. These main curves are stored in the memory and transformed geometrically in order to obtain the minor curves. Such model was prepared in the Matlab-Simulink software, but can be easily implemented using any programming language and applied in an on-line controller. In comparison to the other known simulation methods, the one presented in the paper is easy to understand, and uses simple arithmetical equations, allowing to quickly obtain the inversed model of hysteresis. The inversed model was further used for compensation of a non-saturated hysteresis of the piezo bender actuator and results have also been presented in the paper.

  4. GeoBrain for Facilitating Earth Science Education in Higher-Education Institutes--Experience and Lessons-learned

    NASA Astrophysics Data System (ADS)

    Deng, M.; di, L.

    2007-12-01

    Data integration and analysis are the foundation for the scientific investigation in Earth science. In the past several decades, huge amounts of Earth science data have been collected mainly through remote sensing. Those data have become the treasure for Earth science research. Training students how to discover and use the huge volume of Earth science data in research become one of the most important trainings for making a student a qualified scientist. Being developed by a NASA funded project, the GeoBrain system has adopted and implemented the latest Web services and knowledge management technologies for providing innovative methods in publishing, accessing, visualizing, and analyzing geospatial data and in building/sharing geoscience knowledge. It provides a data-rich online learning and research environment enabled by wealthy data and information available at NASA Earth Observing System (EOS) Data and Information System (EOSDIS). Students, faculty members, and researchers from institutes worldwide can easily access, analyze, and model with the huge amount of NASA EOS data just like they possess such vast resources locally at their desktops. Although still in development, the GeoBrain system has been operational since 2005. A number of education materials have been developed for facilitating the use of GeoBrain as a powerful education tool for Earth science education at both undergraduate and graduate levels. Thousands of online higher-education users worldwide have used GeoBrain services. A number of faculty members in multiple universities have been funded as GeoBrain education partners to explore the use of GeoBrain in the classroom teaching and student research. By summarizing and analyzing the feedbacks from the online users and the education partners, this presentation presents the user experiences on using GeoBrain in Earth science teaching and research. The feedbacks on classroom use of GeoBrain have demonstrated that GeoBrain is very useful for

  5. Accurate modeling of spectral fine-structure in Earth radiance spectra measured with the Global Ozone Monitoring Experiment.

    PubMed

    van Deelen, Rutger; Hasekamp, Otto P; Landgraf, Jochen

    2007-01-10

    We present what we believe to be a novel approach to simulating the spectral fine structure (<1 nm) in measurements of spectrometers such as the Global Ozone Monitoring Experiment (GOME). GOME measures the Earth's radiance spectra and daily solar irradiance spectra from which a reflectivity spectrum is commonly extracted. The high-frequency structures contained in such a spectrum are, apart from atmospheric absorption, caused by Raman scattering and by a shift between the solar irradiance and the Earth's radiance spectrum. Normally, an a priori high-resolution solar spectrum is used to simulate these structures. We present an alternative method in which all the required information on the solar spectrum is retrieved from the GOME measurements. We investigate two approaches for the spectral range of 390-400 nm. First, a solar spectrum is reconstructed on a fine spectral grid from the GOME solar measurement. This approach leads to undersampling errors of up to 0.5% in the modeling of the Earth's radiance spectra. Second, a combination of the solar measurement and one of the Earth's radiance measurement is used to retrieve a solar spectrum. This approach effectively removes the undersampling error and results in residuals close to the GOME measurement noise of 0.1%.

  6. Volcanic tremor and plume height hysteresis from Pavlof Volcano, Alaska.

    PubMed

    Fee, David; Haney, Matthew M; Matoza, Robin S; Eaton, Alexa R; Cervelli, Peter; Schneider, David J; Iezzi, Alexandra M

    2017-01-06

    The March 2016 eruption of Pavlof Volcano, Alaska, produced an ash plume that caused the cancellation of more than 100 flights in North America. The eruption generated strong tremor that was recorded by seismic and remote low-frequency acoustic (infrasound) stations, including the EarthScope Transportable Array. The relationship between the tremor amplitudes and plume height changes considerably between the waxing and waning portions of the eruption. Similar hysteresis has been observed between seismic river noise and discharge during storms, suggesting that flow and erosional processes in both rivers and volcanoes can produce irreversible structural changes that are detectable in geophysical data. We propose that the time-varying relationship at Pavlof arose from changes in the tremor source related to volcanic vent erosion. This relationship may improve estimates of volcanic emissions and characterization of eruption size and intensity.

  7. Volcanic tremor and plume height hysteresis from Pavlof Volcano, Alaska

    NASA Astrophysics Data System (ADS)

    Fee, David; Haney, Matthew M.; Matoza, Robin S.; Van Eaton, Alexa R.; Cervelli, Peter; Schneider, David J.; Iezzi, Alexandra M.

    2017-01-01

    The March 2016 eruption of Pavlof Volcano, Alaska, produced an ash plume that caused the cancellation of more than 100 flights in North America. The eruption generated strong tremor that was recorded by seismic and remote low-frequency acoustic (infrasound) stations, including the EarthScope Transportable Array. The relationship between the tremor amplitudes and plume height changes considerably between the waxing and waning portions of the eruption. Similar hysteresis has been observed between seismic river noise and discharge during storms, suggesting that flow and erosional processes in both rivers and volcanoes can produce irreversible structural changes that are detectable in geophysical data. We propose that the time-varying relationship at Pavlof arose from changes in the tremor source related to volcanic vent erosion. This relationship may improve estimates of volcanic emissions and characterization of eruption size and intensity.

  8. 8 years of experience in international, interdisciplinary and structured doctoral training in Earth system modelling

    NASA Astrophysics Data System (ADS)

    Weitz, Antje; Stevens, Bjorn; Marotzke, Jochem

    2010-05-01

    The mission of the International Max Planck Research School on Earth System Modelling (IMPRS-ESM) is to provide a high quality, modern and structured graduate education to students pursuing a doctoral degree in Earth system modelling. In so doing, the IMPRS-ESM also strives to advance the emerging discipline (or cross-discipline) of Earth system modelling; to provide a framework for attracting the most talented and creative young women and men from around the world to pursue their doctoral education in Germany; to provide advanced as well as specialized academic training and scientific guidance to doctoral students; to encourage academic networking and publication of research results; to better integrate doctoral research at the Max Planck Institute for Meteorology (MPI-M) with education and research at the University of Hamburg and other cooperating institutions. Core elements are rigorous selection of doctoral students, effective academic supervision, advanced academic training opportunities and interdisciplinary communication as well as administrative support. IMPRS-ESM graduates have been recognized with a variety of awards. 85% of our alumni continue a career in research. In this presentation we review the challenges for an interdisciplinary PhD program in Earth system sciences and the types of routines we have implemented to surmount them as well as key elements that we believe contribute to the success of our doctoral program.

  9. Effect of contact angle hysteresis on moving liquid film integrity.

    NASA Technical Reports Server (NTRS)

    Simon, F. F.; Hsu, Y. Y.

    1972-01-01

    A study was made of the formation and breakdown of a water film moving over solid surfaces (teflon, lucite, stainless steel, and copper). The flow rate associated with film formation was found to be higher than the flow rate at which film breakdown occurred. The difference in the flow rates for film formation and film breakdown was attributed to contact angle hysteresis. Analysis and experiment, which are in good agreement, indicated that film formation and film breakdown are functions of the advancing and receding angles, respectively.

  10. Effect of contact angle hysteresis on moving liquid film integrity

    NASA Technical Reports Server (NTRS)

    Simon, F. F.; Hsu, Y. Y.

    1972-01-01

    A study was made of the formation and breakdown of a water film moving over solid surfaces (teflon, lucite, stainless steel, and copper). The flow rate associated with film formation was found to be higher than the flow rate at which film breakdown occurred. The difference in the flow rates for film formation and film breakdown was attributed to contact angle hysteresis. Analysis and experiment, which are in good agreement, indicated that film formation and film breakdown are functions of the advancing and receding angles, respectively.

  11. The hysteresis response of soil respiration and soil CO2 concentration to soil temperature

    NASA Astrophysics Data System (ADS)

    Zhang, Q., Sr.; Katul, G. G.; Oren, R.; Daly, E.; Manzoni, S.; Yang, D.

    2015-12-01

    Diurnal hysteresis between soil temperature (Ts) and both CO2 concentration ([CO2]) and soil respiration rate (Rs) were reported across different field experiments. However, the causes of these hysteresis patterns remain a subject of debate, with biotic and abiotic factors both invoked as explanations. To address these issues, a CO2 gas transport model is developed by combining layer-wise mass conservation for subsurface gas-phase CO2, Fickian diffusion for gas transfer, and a CO2 source term that depends on soil temperature, moisture, and photosynthetic rate. Using this model, a hierarchy of numerical experiments were employed to disentangle the causes of the hysteretic [CO2]-Ts and CO2 flux-Ts (i.e., F -Ts) relations. Model results show that gas transport alone can introduce both [CO2]-Ts and F-Ts hysteresis, and also confirm prior findings that heat flow in soils lead to [CO2] and F(z) being out of phase with Ts, thereby providing another reason for the occurrence of both hysteresis. The area (Ahys) of the [CO2]-Ts hysteresis near the surface increases, while the Ahys of the Rs-Ts hysteresis decreases as soils become wetter. Moreover, a time-lagged carbon input from photosynthesis deformed the [CO2]-Ts and Rs-Ts patterns, causing a change in the loop direction from counterclockwise to clockwise with decreasing time lag. An asymmetric 8-shaped pattern emerged as the transition state between the two loop directions. Tracing the pattern and direction of the hysteretic [CO2]-Ts and Rs-Ts relations can provide new ways to fingerprint the effects of photosynthesis stimulation on soil microbial activity and detect the corresponding time lags. Key words: Hysteresis; Photosynthesis; Soil CO2 concentration; Soil respiration; Soil temperature; Soil moisture

  12. Separation of americium, curium, and rare earths from high-level wastes by oxalate precipitation: experiments with synthetic waste solutions

    SciTech Connect

    Forsberg, C.W.

    1980-01-01

    The separation of trivalent actinides and rare earths from other fission products in high-level nuclear wastes by oxalate precipitation followed by ion exchange (OPIX) was experimentally investigated using synthetic wastes and a small-scale, continuous-flow oxalic acid precipitation and solid-liquid separation system. Trivalent actinide and rare earth oxalates are relatively insoluble in 0.5 to 1.0 M HNO/sub 3/ whereas other fission product oxalates are not. The continuous-flow system consisted of one or two stirred-tank reactors in series for crystal growth. Oxalic acid and waste solutions were mixed in the first tank, with the product solid-liquid slurry leaving the second tank. Solid-liquid separation was tested by filters and by a gravity settler. The experiments determined the fraction of rare earths precipitated and separated from synthetic waste streams as a function of number of reactors, system temperature, oxalic acid concentration, liquid residence time in the process, power input to the stirred-tank reactors, and method of solid-liquid separation. The crystalline precipitate was characterized with respect to form, size, and chemical composition. These experiments are only the first step in converting a proposed chemical flowsheet into a process flowsheet suitable for large-scale remote operations at high activity levels.

  13. An investigation on the hysteresis characteristics of an automotive air spring

    NASA Astrophysics Data System (ADS)

    Liu, H.; Lee, J. C.

    2007-12-01

    Hysteresis is one of major properties of air spring during its compression and rebounding sequences. This study shows hysteresis property of air spring theoretically and experimentally. At first, the theoretical model of the air spring was developed, considering the factor of heat exchange. And then experiments of force responses with displacement excitation signal of various frequencies were implemented. The simulations by using obtained model were performed to compare with experimental results. The results show that simulation results are close to experiment in low excitation frequency from 1 Hz to 0.1 Hz, but there exits some difference between them in very low excitation frequency (quasistatic process).

  14. Managing Hysteresis: Three Cornerstones to Fiscal Stability

    ERIC Educational Resources Information Center

    Weeks, Richard

    2012-01-01

    The effects of the Great Recession of 2007-2009 continue to challenge school business officials (SBOs) and other education leaders as they strive to prepare students for the global workforce. Economists have borrowed a word from chemistry to describe this state of affairs: hysteresis--the lingering effects of the past on the present. Today's SBOs…

  15. Semilinear Parabolic Equations with Preisach Hysteresis

    NASA Astrophysics Data System (ADS)

    Little, Thomas Dan

    A coupled system consisting of a nonlinear parabolic partial differential equation and a family of ordinary differential equations is realized as an abstract Cauchy problem. We establish coercivity and accretiveness estimates for the multi-valued operator in the abstract Cauchy problem, and then apply the Crandall-Liggett theorem to recover the integral solution for the abstract Cauchy problem. A special case of the coupled system corresponds to the Super -Stefan problem, i.e. the delayed phase transition model for a material subjected to super-heating and super-cooling. In this case, the nonlinearity in the parabolic partial differential equation appears as the time derivative of a simple relay hysteresis functional produced by one member of the family of ordinary differential equations. Another special case of the coupled system corresponds to a one-dimensional derivation from Maxwell's equations for a ferromagnetic body under slowly varying field conditions. In this case, the nonlinearity is the time derivative of the classical Preisach hysteresis functional, and the family of ordinary differential equations produce a family of simple relay hysteresis functionals present in the construction of the Preisach hysteresis functional.

  16. Managing Hysteresis: Three Cornerstones to Fiscal Stability

    ERIC Educational Resources Information Center

    Weeks, Richard

    2012-01-01

    The effects of the Great Recession of 2007-2009 continue to challenge school business officials (SBOs) and other education leaders as they strive to prepare students for the global workforce. Economists have borrowed a word from chemistry to describe this state of affairs: hysteresis--the lingering effects of the past on the present. Today's SBOs…

  17. Circuit increases capability of hysteresis synchronous motor

    NASA Technical Reports Server (NTRS)

    Markowitz, I. N.

    1967-01-01

    Frequency and phase detector circuit enables a hysteresis synchronous motor to drive a load of given torque value at a precise speed determined by a stable reference. This technique permits driving larger torque loads with smaller motors and lower power drain.

  18. Rotational versus alternating hysteresis losses in nonoriented soft magnetic laminations

    NASA Astrophysics Data System (ADS)

    Fiorillo, F.; Rietto, A. M.

    1993-05-01

    Rotational and alternating hysteresis losses have been investigated in theory and experiment in nonoriented soft magnetic laminations. Attention has been focused on the dependence of energy loss on peak magnetization Ip. The experiments, performed in a wide induction range (˜2×10-4 T≤Ip≤˜1.6 T), show that the ratio between rotational and alternating energy losses Whr/Wha is a monotonically decreasing function of Ip. A quantitative theoretical investigation is carried out through modeling of the magnetization process under rotating field and its relation to processes under alternating field. Three basic mechanisms of magnetization rotation are considered: linear combination of unidirectional hysteresis loops at low inductions (Rayleigh region), cyclic rearrangement of magnetic domains between different easy directions at intermediate inductions, and coherent spin rotation toward the approach to magnetic saturation. The ensuing predicted behavior of Whr/Wha is found to be in good agreement with the experiments performed in nonoriented low carbon steel and 3% FeSi laminations.

  19. Origin of hysteresis in bed form response to unsteady flows

    NASA Astrophysics Data System (ADS)

    Martin, Raleigh L.; Jerolmack, Douglas J.

    2013-03-01

    Field and laboratory studies indicate that changes in riverbed morphology often lag changes in water discharge. This lagged response produces hysteresis in the relationship between water discharge and bed form geometry. To understand these phenomena, we performed flume experiments to observe the response of a sand bed to step increases and decreases in water discharge. For an abrupt rise in discharge, we observed that bed forms grew rapidly by collision and merger of bed forms migrating with different celerities. Growth rate slowed as bed forms approached equilibrium with the higher discharge regime. After an abrupt discharge drop, bed form decay occurred through formation of smaller secondary bed forms, in equilibrium with the lower discharge, which cannibalized the original, relict features. We present a simple model framework to quantitatively predict time scales of bed form adjustment to flow changes, based on equilibrium bed form heights, lengths, and celerities at low and high flows. For rising discharge, the model assumes that all bed form collisions result in irreversible merger, due to a dispersion of initial celerities. For falling discharge, we derive a diffusion model for the decay of relict high-stage features. Our models predict the form and time scale of experimental bed form adjustments. Additional experiments applying slow and fast triangular flood waves show that bed form hysteresis occurs only when the time scale of flow change is faster than the modeled (and measured) bed form adjustment time. We show that our predicted adjustment time scales can also be used to predict the occurrence of bed form hysteresis in natural floods.

  20. Soil and crop management experiments in the Laboratory Biosphere: an analogue system for the Mars on Earth(R) facility.

    PubMed

    Silverstone, S; Nelson, M; Alling, A; Allen, J P

    2005-01-01

    During the years 2002 and 2003, three closed system experiments were carried out in the "Laboratory Biosphere" facility located in Santa Fe, New Mexico. The program involved experimentation of "Hoyt" Soy Beans, (experiment #1) USU Apogee Wheat (experiment #2) and TU-82-155 sweet potato (experiment #3) using a 5.37 m2 soil planting bed which was 30 cm deep. The soil texture, 40% clay, 31% sand and 28% silt (a clay loam), was collected from an organic farm in New Mexico to avoid chemical residues. Soil management practices involved minimal tillage, mulching, returning crop residues to the soil after each experiment and increasing soil biota by introducing worms, soil bacteria and mycorrhizae fungi. High soil pH of the original soil appeared to be a factor affecting the first two experiments. Hence, between experiments #2 and #3, the top 15 cm of the soil was amended using a mix of peat moss, green sand, humates and pumice to improve soil texture, lower soil pH and increase nutrient availability. This resulted in lowering the initial pH of 8.0-6.7 at the start of experiment #3. At the end of the experiment, the pH was 7.6. Soil nitrogen and phosphorus has been adequate, but some chlorosis was evident in the first two experiments. Aphid infestation was the only crop pest problem during the three experiments and was handled using an introduction of Hyppodamia convergens. Experimentation showed there were environmental differences even in this 1200 cubic foot ecological system facility, such as temperature and humidity gradients because of ventilation and airflow patterns which resulted in consequent variations in plant growth and yield. Additional humidifiers were added to counteract low humidity and helped optimize conditions for the sweet potato experiment. The experience and information gained from these experiments are being applied to the future design of the Mars On Earth(R) facility (Silverstone et al., Development and research program for a soil

  1. Soil and crop management experiments in the Laboratory Biosphere: An analogue system for the Mars on Earth ® facility

    NASA Astrophysics Data System (ADS)

    Silverstone, S.; Nelson, M.; Alling, A.; Allen, J. P.

    During the years 2002 and 2003, three closed system experiments were carried out in the "Laboratory Biosphere" facility located in Santa Fe, New Mexico. The program involved experimentation of "Hoyt" Soy Beans, (experiment #1) USU Apogee Wheat (experiment #2) and TU-82-155 sweet potato (experiment #3) using a 5.37 m 2 soil planting bed which was 30 cm deep. The soil texture, 40% clay, 31% sand and 28% silt (a clay loam), was collected from an organic farm in New Mexico to avoid chemical residues. Soil management practices involved minimal tillage, mulching, returning crop residues to the soil after each experiment and increasing soil biota by introducing worms, soil bacteria and mycorrhizae fungi. High soil pH of the original soil appeared to be a factor affecting the first two experiments. Hence, between experiments #2 and #3, the top 15 cm of the soil was amended using a mix of peat moss, green sand, humates and pumice to improve soil texture, lower soil pH and increase nutrient availability. This resulted in lowering the initial pH of 8.0-6.7 at the start of experiment #3. At the end of the experiment, the pH was 7.6. Soil nitrogen and phosphorus has been adequate, but some chlorosis was evident in the first two experiments. Aphid infestation was the only crop pest problem during the three experiments and was handled using an introduction of Hyppodamia convergens. Experimentation showed there were environmental differences even in this 1200 cubic foot ecological system facility, such as temperature and humidity gradients because of ventilation and airflow patterns which resulted in consequent variations in plant growth and yield. Additional humidifiers were added to counteract low humidity and helped optimize conditions for the sweet potato experiment. The experience and information gained from these experiments are being applied to the future design of the Mars On Earth ® facility (Silverstone et al., Development and research program for a soil

  2. TRAPPED PROTON FLUXES AT LOW EARTH ORBITS MEASURED BY THE PAMELA EXPERIMENT

    SciTech Connect

    Adriani, O.; Bongi, M.; Barbarino, G. C.; Bazilevskaya, G. A.; Bellotti, R.; Bruno, A.; Boezio, M.; Bonvicini, V.; Carbone, R.; Bogomolov, E. A.; Bottai, S.; Cafagna, F.; Campana, D.; Carlson, P.; Casolino, M.; De Donato, C.; De Santis, C.; De Simone, N.; Felice, V. Di; Castellini, G.; and others

    2015-01-20

    We report an accurate measurement of the geomagnetically trapped proton fluxes for kinetic energy above ∼70 MeV performed by the PAMELA mission at low Earth orbits (350 ÷ 610 km). Data were analyzed in the frame of the adiabatic theory of charged particle motion in the geomagnetic field. Flux properties were investigated in detail, providing a full characterization of the particle radiation in the South Atlantic Anomaly region, including locations, energy spectra, and pitch angle distributions. PAMELA results significantly improve the description of the Earth's radiation environment at low altitudes, placing important constraints on the trapping and interaction processes, and can be used to validate current trapped particle radiation models.

  3. Geodesy and gravity experiment in earth orbit using a superconducting gravity gradiometer

    NASA Technical Reports Server (NTRS)

    Paik, H. J.

    1985-01-01

    A superconducting gravity gradiometer is under development with NASA support for space application. It is planned that a sensitive three-axis gravity gradiometer will be flown in a low-altitude (about 160 km) polar orbit in the 1990's for the purpose of obtaining a high-resolution gravity map of the earth. The large twice-an-orbit term in the harmonic expansion of gravity coming from the oblateness of the earth can be analyzed to obtain a precision test of the inverse square law at a distance of 100-1000 km. In this paper, the design, operating principle, and performance of the superconducting gravity gradiometer are described. The concept of a gravity-gradiometer mission (GGM), which is in an initial stage of development is discussed. In particular, requirements that such a mission imposes on the design of the cryogenic spacecraft will be addressed.

  4. Geodesy and gravity experiment in earth orbit using a superconducting gravity gradiometer

    NASA Technical Reports Server (NTRS)

    Paik, H. J.

    1985-01-01

    A superconducting gravity gradiometer is under development with NASA support for space application. It is planned that a sensitive three-axis gravity gradiometer will be flown in a low-altitude (about 160 km) polar orbit in the 1990's for the purpose of obtaining a high-resolution gravity map of the earth. The large twice-an-orbit term in the harmonic expansion of gravity coming from the oblateness of the earth can be analyzed to obtain a precision test of the inverse square law at a distance of 100-1000 km. In this paper, the design, operating principle, and performance of the superconducting gravity gradiometer are described. The concept of a gravity-gradiometer mission (GGM), which is in an initial stage of development is discussed. In particular, requirements that such a mission imposes on the design of the cryogenic spacecraft will be addressed.

  5. Creating the Public Connection: Interactive Experiences with Real-Time Earth and Space Science Data

    NASA Technical Reports Server (NTRS)

    Reiff, Patricia H.; Ledley, Tamara S.; Sumners, Carolyn; Wyatt, Ryan

    1995-01-01

    The Houston Museum of Natural Sciences is less than two miles from Rice University, a major hub on the Internet. This project links these two institutions so that NASA real-time data and imagery can flow via Rice to the Museum where it reaches the public in the form of planetarium programs, computer based interactive kiosks, and space and Earth science problem solving simulation. Through this program at least 200,000 visitors annually (including every 4th and 7th grader in the Houston Independent School District) will have direct exposure to the Earth and space research being conducted by NASA and available over the Internet. Each information conduit established between Rice University and the Houston Museum of Natural Science will become a model for public information dissemination that can be replicated nationally in museums, planetariums, Challenger Centers, and schools.

  6. Non-equilibrium fluctuations on earth and in micro-gravity. The GRADFLEX experiment

    NASA Astrophysics Data System (ADS)

    Vailati, A.; Cerbino, R.; Mazzoni, S.; Giglio, M.; Takacs, C. J.; Cannell, D. S.

    2011-12-01

    We present the results of measurements of giant nonequilibrium fluctuations in a single component fluid (density fluctuations) and a mixture (concentration fluctuations) driven by applied temperature gradients, both on Earth and in space. Flight data were obtained during the September 2007 FOTON M3 mission. Spatial power spectra obtained using the shadowgraph method, during flight, confirm that the asymptotic behaviour extends to such low wave vector q, as to be limited by the sample thickness. Quantitative comparison with theory is provided, and is generally quite good. Temporal sequences of shadowgraph images for the mixture, both on Earth and during flight will be presented to emphasize the dramatic differences. Fluctuation lifetimes of thousands of seconds were observed during flight. The rugged but sensitive shadowgraph scattering method (phase fluctuations below 10 milliradians measured to within a few percent absolute accuracy) will be described briefly.

  7. Creating the Public Connection: Interactive Experiences with Real-Time Earth and Space Science Data

    NASA Technical Reports Server (NTRS)

    Reiff, Patricia H.; Ledley, Tamara S.; Sumners, Carolyn; Wyatt, Ryan

    1995-01-01

    The Houston Museum of Natural Sciences is less than two miles from Rice University, a major hub on the Internet. This project links these two institutions so that NASA real-time data and imagery can flow via Rice to the Museum where it reaches the public in the form of planetarium programs, computer based interactive kiosks, and space and Earth science problem solving simulation. Through this program at least 200,000 visitors annually (including every 4th and 7th grader in the Houston Independent School District) will have direct exposure to the Earth and space research being conducted by NASA and available over the Internet. Each information conduit established between Rice University and the Houston Museum of Natural Science will become a model for public information dissemination that can be replicated nationally in museums, planetariums, Challenger Centers, and schools.

  8. Contact angle hysteresis: a different view and a trivial recipe for low hysteresis hydrophobic surfaces.

    PubMed

    Krumpfer, Joseph W; McCarthy, Thomas J

    2010-01-01

    Contact angle hysteresis is addressed from two perspectives. The first is an analysis of the events that occur during motion of droplets on superhydrophobic surfaces. Hysteresis is discussed in terms of receding contact line pinning and the tensile failure of capillary bridges. The sign of the curvature of the solid surface is implicated as playing a key role. The second is the report of a new method to prepare smooth low hysteresis surfaces. The thermal treatment of oxygen plasma-cleaned silicon wafers with trimethylsilyl-terminated linear poly(dimethylsiloxane) (PDMS - commercial silicone oils) in disposable glass vessels is described. This treatment renders silicon/silica surfaces that contain covalently attached PDMS chains. The grafted layers of nanometre scale thickness are liquid-like (rotationally dynamic at room temperature), decrease activation barriers for contact line motion and minimize water contact angle hysteresis. This simple method requires neither sophisticated techniques nor substantial laboratory skills to perform.

  9. Nonlinear Hysteresis in an Endochronic Solid

    DTIC Science & Technology

    1994-01-04

    LEWKOWICZ Co tract Manager B&ach Chief ,SoIid Earth Geophysics Branch Solid Earth Geophysics Branch Earth Sciences Division Earth Sciences Division J...Hoffman Laboratory, Harvard University SAIC Dept. of Earth Atmos. & Planetary Sciences 10260 Campus Point Drive 20 Oxford Street San Diego, CA 92121...Prof. Lane R. Johnson Prof. Thorne Lay Seismographic Station Institute of Tectonics University of California Earth Science Board Berkeley, CA 94720

  10. Fatigue and hysteresis modeling of ferroelectric materials

    NASA Astrophysics Data System (ADS)

    Yoo, In. K.; Desu, Seshu B.

    1993-10-01

    Due to their nonlinear properties, ferroelectric materials are ideal candidates for smart materials. Degradation properties such as low voltage breakdown, fatigue, and aging have been major problems in commercial applications of these materials. Such degradations affect the lifetime of ferroelectric materials. Therefore, it is important to understand degradation for reliability improvement. In this article, recent studies on fatigue and hysteresis of ferroelectric ceramics such as Lead Zirconate Titanate (PZT) thin films is reviewed. A new fatigue model is discussed in detail which is based on effective one-directional movement of defects by internal field difference, defect entrapment at the ferroelectrics-electrode interface, and resultant polarization loss at the interface. A fatigue equation derived from this model is presented. Fatigue parameters such as initial polarization, piling constant, and decay constant are defined from the fatigue equation and voltage and temperature dependence of fatigue parameters are discussed. The jump distance of defect calculated from voltage dependence of the decay constant is close to the lattice constant of ferroelectric materials, which implies that oxygen or lead vacancies migrate either parallel or antiparallel to the polarization direction. From the temperature dependence of the decay constant, it is shown that the activation energy for domain wall movement plays an important role in fatigue. The hysteresis model of ferroelectrics is shown using polarization reversal. The hysteresis loop is made by four polarization stages: nucleation, growth, merging, and shrinkage of domains. The hysteresis equation confirms that dielectric viscosity controls hysteresis properties, and temperature dependence of the coefficient of dielectric viscosity is also discussed in conjunction with fatigue mechanism.

  11. Origin of plate tectonics: Grain-damage, inheritance and hysteresis

    NASA Astrophysics Data System (ADS)

    Bercovici, D.; Ricard, Y. R.

    2015-12-01

    The emergence of plate tectonics is enigmatic because of the lack of observations in the early Archean as well as the challenge of understanding how plates form. The damage theory of lithospheric weakening by grain-reduction provides a physical framework for plate generation. This model builds on grain-scale physics to describe planetary-scale processes, and is consistent with lab and field observations of polycrystalline rocks and lithospheric mylonites. Grain-damage accounts for the evolution of damage and healing by grain growth, hence predicts plate boundary formation and longevity, and how they depend on surface conditions. The establishment of global plate tectonics likely started between >4Ga and 2.7Ga, and may have taken over a billion years to develop. Under Earth-like conditions, grain-damage combined with intermittent Archean protosubduction produces persistent weak zones that accumulate into well developed plates by 3Ga. However, Venus' hotter surface promotes healing, suppresses damage and inhibits weak zone accumulation, which suggests why plate tectonics failed to spread on our sister planet. New work posits that interface damage is possibly suppressed at moderate grain-size; this induces a hysteresis loop wherein three equilibrium deformation branches coexist. These branches include a stable large-grain, weakly-deforming state in dislocation creep, a stable small-grain rapidly-deforming state in diffusion creep analogous to mylonites, and an unstable intermediate-grain state. At the right conditions, a lithosphere can acquire two stable deformation states characteristic of plate tectonics; i.e., both slowly deforming plate interiors and rapidly deforming plate boundaries can co-exist. Earth currently sits inside the hysteresis loop and can have coexisting deformation states, while Venus sits at the end of the loop where only the weakly deforming branch dominates. The hot post-Hadean Earth might have had peak deformation only on the weakly

  12. A Geograns update. New experiences to teach earth sciences to students older than 55

    NASA Astrophysics Data System (ADS)

    Cerdà, A.; Pinazo, S.

    2009-04-01

    How to teach earth science to students that have access to the university after the age of 55 is a challenge due to the different background of the students. They ranged from those with only basic education (sometimes they finished school at the age of 9) to well educate students such as university professors, physicians or engineers. Students older than 55 are enrolled in what is called the university programme NauGran project at the University of Valencia. They follow diverse topics, from health science to Arts. Since 2006 the Department of Geography and the NauGran project developed the Club for Geographers and Walkers called Geograns. The objective is to teach Earth Science in the field as a strategy to improve the knowledge of the students with a direct contact with the territory. This initiative reached a successful contribution by the students, with 70 students registered. The successful strategy we have developed since then is to base our teaching on field work. Every lecture is related to some visits to the field. A pre-excursion lecture introduces the key questions of the study site (hydrology, geology, botany, geomorphology…). During the field work we review all the topics and the students are encouraged to ask and discuss any of the topics studied. Finally, a post-excursion lecture is given to review the acquired knowledge. During the last academic year 2007-2008 the excursion focussed on: (i) energy sources: problems and solutions, with visit to nuclear, wind and hydraulic power stations; (i) human disturbances and humankind as landscaper, with visits to wetlands, river gorges and Iberian settlements; and (iii) human activities and economical resources, with visits to vineyards and wineries and orange fields devoted to organic farming. This is being a positive strategy to teach Earth Science to a wide and heterogeneous group of students, as they improve their knowledge with a direct contact with the landscape, other colleagues and teachers in the

  13. Torque meter aids study of hysteresis motor rings

    NASA Technical Reports Server (NTRS)

    Cole, M.

    1967-01-01

    Torque meter, simulating hysteresis motor operation, allows rotor ring performance characteristics to be analyzed. The meter determines hysteresis motor torque and actual stresses of the ring due to its mechanical situation and rotation, aids in the study of asymmetries or defects in motor rings, and measures rotational hysteresis.

  14. The PROCESS experiment: an astrochemistry laboratory for solid and gaseous organic samples in low-earth orbit.

    PubMed

    Cottin, Hervé; Guan, Yuan Yong; Noblet, Audrey; Poch, Olivier; Saiagh, Kafila; Cloix, Mégane; Macari, Frédérique; Jérome, Murielle; Coll, Patrice; Raulin, François; Stalport, Fabien; Szopa, Cyril; Bertrand, Marylène; Chabin, Annie; Westall, Frances; Chaput, Didier; Demets, René; Brack, André

    2012-05-01

    The PROCESS (PRebiotic Organic ChEmistry on the Space Station) experiment was part of the EXPOSE-E payload outside the European Columbus module of the International Space Station from February 2008 to August 2009. During this interval, organic samples were exposed to space conditions to simulate their evolution in various astrophysical environments. The samples used represent organic species related to the evolution of organic matter on the small bodies of the Solar System (carbonaceous asteroids and comets), the photolysis of methane in the atmosphere of Titan, and the search for organic matter at the surface of Mars. This paper describes the hardware developed for this experiment as well as the results for the glycine solid-phase samples and the gas-phase samples that were used with regard to the atmosphere of Titan. Lessons learned from this experiment are also presented for future low-Earth orbit astrochemistry investigations.

  15. Laurel Clark Earth Camp: A Program for Teachers and Students to Explore Their World and Study Global Change Through Field-Experience and Satellite Images

    NASA Astrophysics Data System (ADS)

    Buxner, S.; Orchard, A.; Colodner, D.; Schwartz, K.; Crown, D. A.; King, B.; Baldridge, A.

    2012-03-01

    The Laurel Clark Earth Camp program provides middle and high school students and teachers opportunities to explore local environmental issues and global change through field-experiences, inquiry exercises, and exploring satellite images.

  16. Hysteresis in myo-inositol utilization by Salmonella Typhimurium.

    PubMed

    Hellinckx, Jessica; Fuchs, Thilo M

    2016-12-27

    Growth of Salmonella enterica serovar Typhimurium strain 14028 with myo-inositol (MI) as the sole carbon and energy source is characterized by a bistable phenotype that manifests in a growth phenotype with an extraordinarily long and length-variable lag phase. However, in the presence of hydrogen carbonate, in the absence of IolR that represses the MI degradation pathway, or if cells are already adapted to minimal medium (MM) with MI, the lag phase is drastically shortened, and the bistable phenotype is abolished. We hypothesized that memory development or hysteresis is a further characteristic of MI degradation by S. Typhimurium; therefore, we investigated the transition from a short to a long lag phase in more detail. Growth experiments demonstrated that memory on the population level is successively lost within approximately 8 hr after cells, which had been adapted to MI utilization, were transferred to lysogeny broth (LB) medium. Flow cytometry (FC) analysis using a chromosomal fusion to PiolE , a promoter controlling the expression of the enzymatic genes iolE and iolG involved in MI degradation, indicated a gradual reversion within a few hours from a population in the "ON" status with respect to iolE transcription to one that is mainly in the "OFF" status. Growth and FC experiments revealed that IolR does not affect hysteresis.

  17. Temperature effects on alkaline earth metal ions adsorption on gibbsite: approaches from macroscopic sorption experiments and molecular dynamics simulations.

    PubMed

    Katz, Lynn E; Criscenti, Louise J; Chen, Chia-chen; Larentzos, James P; Liljestrand, Howard M

    2013-06-01

    Two approaches, macroscopic adsorption experiments and molecular dynamics simulations, were employed to study the effect of temperature on alkaline earth metals adsorption on gibbsite surfaces. Increased reaction temperature enhanced the extent of metal ion adsorption for all of the alkaline earth metals studied. Whereas Mg(2+) and Sr(2+) adsorption displayed dependence on ionic strength, Sr(2+) adsorption exhibited less dependence on background ionic strength regardless of temperature. The ionic strength dependence was attributed to outer-sphere complexation reactions. The ionic strength effect on metal ion removal decreased with increasing temperature for both metals. Ba(2+) removal by gibbsite, on the other hand, was not affected by ionic strength. Results from molecular dynamics simulations were in agreement with the findings of the experimental study. The amount of thermal energy required to remove waters of hydration from the metal cation and the ratio of outer-sphere to inner-sphere complexation decreased with increasing ionic radii. It was observed from both macroscopic and molecular approaches that the tendency to form inner-sphere complexes on gibbsite decreased in the order: Ba(2+)>Sr(2+)>Mg(2+) and that the common assumption that alkaline earth metal ions form outer-sphere complexes appears to be dependent on ionic radius and temperature.

  18. Explicit solution of the spectral radiance in integrating spheres with application to the Earth Radiation Budget Experiment ground calibration

    NASA Technical Reports Server (NTRS)

    Halyo, Nesim; Taylor, Deborah B.

    1988-01-01

    An explicit solution of the spectral radiation leaving an arbitrary point on the wall of a spherical cavity with diffuse reflectivity is obtained. A general measurement equation is obtained that describes the output of a sensor measuring the sphere output within a given field of view and with specified angular and spectral responses. The results are applied to the Earth Radiation Budget Experiment (ERBE) integrating sphere. It is shown that by using appropriate interpretation and processing, a high-accuracy shortwave calibration of the ERBE sensors can be achieved.

  19. Current sheets in the Earth's magnetosphere and in laboratory experiments: The magnetic field structure and the Hall effect

    NASA Astrophysics Data System (ADS)

    Frank, A. G.; Artemyev, A. V.; Zelenyi, L. M.

    2016-10-01

    The main characteristics of current sheets (CSs) formed in laboratory experiments are compared with the results of satellite observations of CSs in the Earth's magnetotail. We show that many significant features of the magnetic field structure and the distributions of plasma parameters in laboratory and magnetospheric CSs exhibit a qualitative similarity, despite the enormous differences of scales, absolute values of plasma parameters, magnetic fields, and currents. In addition to a qualitative comparison, we give a number of dimensionless parameters that demonstrate the possibility of laboratory modeling of the processes occurring in the magnetosphere.

  20. Comparison of cloud forcing derived from the Earth Radiation Budget Experiment with that simulated by the NCAR Community Climate Model

    NASA Technical Reports Server (NTRS)

    Kiehl, J. T.; Ramanathan, V.

    1990-01-01

    The cloud radiative forcing derived from the Earth Radiation Budget Experiment (ERBE) data was compared with cloud forcing simulated by a T42 version of the NCAR Community Climate Model (CCM). The comparison indicates a number of deficiencies in the CCM. Namely, it is shown that the model emits substantially more long-wave radiation than is observed by ERBE. This overestimation is attributed to two model characteristics: (1) the model is too dry and thus reduces the greenhouse longwave radiation effect of the atmosphere (permitting more longwave radiation to escape into space); and (2) the effective high cloud amount is quite small in the model.

  1. Landing in the future: Biological experiments on Earth and in space orbit

    NASA Technical Reports Server (NTRS)

    Pokrovskiy, A.

    1980-01-01

    The development of an Earth biosatellite to duplicate the parameters of pressure, temperature, humidity and others in a space environment onboard Cosmos-1129 is discussed. Effects of a space environment on fruit flies, dogs, laboratory rats in procreation, behavior, stress, biorhythm, body composition, gravitation preference, and cell cultures are examined. The space environment for agricultural products is also studied. The effects of heavy nuclei of galactic space radiation on biological objects inside and outside the satellite is studied, and methods of electrostatic protection are developed.

  2. Landing in the future: Biological experiments on Earth and in space orbit

    NASA Astrophysics Data System (ADS)

    Pokrovskiy, A.

    1980-09-01

    The development of an Earth biosatellite to duplicate the parameters of pressure, temperature, humidity and others in a space environment onboard Cosmos-1129 is discussed. Effects of a space environment on fruit flies, dogs, laboratory rats in procreation, behavior, stress, biorhythm, body composition, gravitation preference, and cell cultures are examined. The space environment for agricultural products is also studied. The effects of heavy nuclei of galactic space radiation on biological objects inside and outside the satellite is studied, and methods of electrostatic protection are developed.

  3. Excited state absorption in glasses activated with rare earth ions: Experiment and modeling

    NASA Astrophysics Data System (ADS)

    Piatkowski, Dawid; Mackowski, Sebastian

    2012-10-01

    We present semiempirical approach based on the Judd-Ofelt theory and apply it for modeling the spectral properties of fluoride glasses activated with the rare earth (RE) ions. This method provide a powerful tool for simulating both ground state absorption (GSA) and excited state absorption (ESA) spectra of RE ions, e.g. Nd3+, Ho3+, Er3+ and Tm3+ in the ZBLAN glass matrix. The results of theoretical calculations correspond to the experimentally measured data. We also demonstrate that the spectra obtained using the presented approach are applicable in the analysis of up-conversion excitation schemes in these optoelectronically relevant materials.

  4. Photographic coronagraph, Skylab particulate experiment T025. [earth atmospheric pollution and Kohoutek Comet monitoring

    NASA Technical Reports Server (NTRS)

    Giovane, F.; Schuerman, D. W.; Greenberg, J. M.

    1977-01-01

    A photographic coronagraph, built to monitor Skylab's extravehicular contamination, is described. This versatile instrument was used to observe the earth's vertical aerosol distribution and Comet Kohoutek (1973f) near perihelion. Although originally designed for deployment from the solar airlock, the instrument was modified for EVA operation when the airlock was rendered unusable. The results of the observations made in four EVA's were almost completely ruined by the failure of a Skylab operational camera used with the coronagraph. Nevertheless, an aerosol layer at 48 km was discovered in the southern hemisphere from the few useful photographs.

  5. Integrating Real-time, Real-world Geoscience Experiences into Classroom Instruction with EarthLabs and the JOIDES Resolution

    NASA Astrophysics Data System (ADS)

    Mote, A. S.; Lockwood, J.; Ellins, K. K.; Haddad, N.; Cooper, S. K.; Ledley, T. S.

    2013-12-01

    Inspiring the next generation of geoscientists and preparing students for the 21st century workforce requires lifting science outside of the classroom and giving learners the opportunity to think critically about real-world geoscience problems. The EarthLabs suite of climate science modules challenges students with a variety of learning experiences including current scientific data analysis, computer visualizations, satellite imagery, and engaging videos. Each module includes a series of hands-on activities to allow students to explore Earth's complex and dynamic climate history, leading to a deeper understanding of present and future changes to our planet. A new EarthLabs module in development 'Climate Detectives: An Expedition on board the JOIDES Resolution," focuses on Integrated Ocean Drilling Program (IODP) Expedition 341 to Southern Alaska. The module is structured to allow students to work collaboratively, mimicking scientific research groups on the JOIDES Resolution. As students assume the role of a scientist, learn about data collection methods, and analyze authentic data, they learn about the climate history and tectonic processes of the Southern Alaska continental margin, as well as explore the relationship between climate, sedimentation, and tectonics. The Project Based Learning (PBL) approach used in the module teaches students how to analyze data and solve problems like scientists, strengthening the development of higher order thinking skills and preparing them for college coursework. The 'Climate Detectives' Module also provides students with opportunities to interact with scientists through live video conferencing and pre-recorded video presentations by scientists. In this presentation, Expedition 341 Education Officer, Alison Mote, describes the new module, which takes students on an educational journey as they learn about the scientific objectives, methods, and data collection tools scientists use to conduct research on sediment cores retrieved

  6. Study of contact angle hysteresis using the Cellular Potts Model.

    PubMed

    Mortazavi, Vahid; D'Souza, Roshan M; Nosonovsky, Michael

    2013-02-28

    We use the Cellular Potts Model (CPM) to study the contact angle (CA) hysteresis in multiphase (solid-liquid-vapour) systems. We simulate a droplet over the tilted patterned surface, and a bubble placed under the surface immersed in liquid. The difference between bubbles and droplets was discussed through their CA hysteresis. Dependency of CA hysteresis on the surface structure and other parameters was also investigated. This analysis allows decoupling of the 1D (pinning of the triple line) and 2D (adhesion hysteresis in the contact area) effects and provides new insight into the nature of CA hysteresis.

  7. Magnetic hysteresis of limestones: facies control?

    NASA Astrophysics Data System (ADS)

    Borradaile, Graham J.; Chow, Nancy; Werner, Tomasz

    1993-03-01

    The hysteresis properties of 116 non-red, marine limestones from 92 localities indicate that remanence is carried by magnetite of pseudo-single-domain (PSD) and small multidomain (MD) size. Pelagic limestones have paramagnetic matrices and hysteresis properties compatible with larger PSD or MD grain sizes of magnetite, probably associated with detrital clay minerals introduced by pelagic rain-out. Thus they may be less suitable recorders of stable remanence. Other limestone facies (excepting dolomitized examples) have diamagnetic matrices. They include shallow—subtidal limestones which tend to have smaller PSD sizes of magnetite, as do backreef—lagoonal, undifferentiated-shelf and reef facies. It is believed that the wide geographical and temporal range of samples minimizes effects related to post-compaction groundwater flow (late diagenesis) and that the associations recognized should be tested in future studies.

  8. Domain Dynamics in Piezoresponse Force Spectroscopy: Quantitative Deconvolution and Hysteresis Loop Fine Structure

    SciTech Connect

    Bdikin, Igor; Kholkin, Andrei; Morozovska, A. N.; Svechnikov, S. V.; Kim, S.-H.; Kalinin, Sergei V

    2008-01-01

    Domain dynamics in the Piezoresponse Force Spectroscopy (PFS) experiment is studied using the combination of local hysteresis loop acquisition with simultaneous domain imaging. The analytical theory for PFS signal from domain of arbitrary cross-section and length is developed for the analysis of experimental data on Pb(Zr,Ti)O3 polycrystalline films. The results suggest formation of oblate domain at early stage of the nucleation and growth, consistent with efficient screening of depolarization field. The fine structure of the hysteresis loop is shown to be related to the observed jumps in the domain geometry during domain wall propagation (nanoscale Barkhausen jumps), indicative of strong domain-defect interactions.

  9. Stability Limits of Capillary Bridges: How Contact Angle Hysteresis Affects Morphology Transitions of Liquid Microstructures.

    PubMed

    de Ruiter, Riëlle; Semprebon, Ciro; van Gorcum, Mathijs; Duits, Michèl H G; Brinkmann, Martin; Mugele, Frieder

    2015-06-12

    The equilibrium shape of a drop in contact with solid surfaces can undergo continuous or discontinuous transitions upon changes in either drop volume or surface energies. In many instances, such transitions involve the motion of the three-phase contact line and are thus sensitive to contact angle hysteresis. Using a combination of electrowetting-based experiments and numerical calculations, we demonstrate for a generic sphere-plate confinement geometry how contact angle hysteresis affects the mechanical stability of competing axisymmetric and nonaxisymmetric drop conformations and qualitatively changes the character of transitions between them.

  10. ISO 19115 Experiences in NASA's Earth Observing System (EOS) ClearingHOuse (ECHO)

    NASA Astrophysics Data System (ADS)

    Cechini, M. F.; Mitchell, A.

    2011-12-01

    Metadata is an important entity in the process of cataloging, discovering, and describing earth science data. As science research and the gathered data increases in complexity, so does the complexity and importance of descriptive metadata. To meet these growing needs, the metadata models required utilize richer and more mature metadata attributes. Categorizing, standardizing, and promulgating these metadata models to a politically, geographically, and scientifically diverse community is a difficult process. An integral component of metadata management within NASA's Earth Observing System Data and Information System (EOSDIS) is the Earth Observing System (EOS) ClearingHOuse (ECHO). ECHO is the core metadata repository for the EOSDIS data centers providing a centralized mechanism for metadata and data discovery and retrieval. ECHO has undertaken an internal restructuring to meet the changing needs of scientists, the consistent advancement in technology, and the advent of new standards such as ISO 19115. These improvements were based on the following tenets for data discovery and retrieval: + There exists a set of 'core' metadata fields recommended for data discovery. + There exists a set of users who will require the entire metadata record for advanced analysis. + There exists a set of users who will require a 'core' set metadata fields for discovery only. + There will never be a cessation of new formats or a total retirement of all old formats. + Users should be presented metadata in a consistent format of their choosing. In order to address the previously listed items, ECHO's new metadata processing paradigm utilizes the following approach: + Identify a cross-format set of 'core' metadata fields necessary for discovery. + Implement format-specific indexers to extract the 'core' metadata fields into an optimized query capability. + Archive the original metadata in its entirety for presentation to users requiring the full record. + Provide on-demand translation of

  11. From Earth to Heaven: Using "Newton's Cannon" Thought Experiment for Teaching Satellite Physics

    ERIC Educational Resources Information Center

    Velentzas, Athanasios; Halkia, Krystallia

    2013-01-01

    Thought Experiments are powerful tools in both scientific thinking and in the teaching of science. In this study, the historical Thought Experiment (TE) "Newton's Cannon" was used as a tool to teach concepts relating to the motion of satellites to students at upper secondary level. The research instruments were: (a) a…

  12. From Earth to Heaven: Using "Newton's Cannon" Thought Experiment for Teaching Satellite Physics

    ERIC Educational Resources Information Center

    Velentzas, Athanasios; Halkia, Krystallia

    2013-01-01

    Thought Experiments are powerful tools in both scientific thinking and in the teaching of science. In this study, the historical Thought Experiment (TE) "Newton's Cannon" was used as a tool to teach concepts relating to the motion of satellites to students at upper secondary level. The research instruments were: (a) a…

  13. Hysteresis modeling in piezoceramic actuator systems

    NASA Astrophysics Data System (ADS)

    Raghavan, A.; Seshu, P.; Gandhi, Prasanna S.

    2003-10-01

    Piezoceramics are potential sensors and actuators for a wide range of applications in smart structures and systems, including shape control of radar and satellite antennas, mirrors and MEMS actuators. Piezoceramic materials are ferroelectric, and they fundamentally exhibit hysteresis characteristics when displacement is plotted against an applied electric field. The maximum error due to hysteresis is found to be as much as 10 - 15% of the path covered if the actuators are run in an open-loop fashion. These errors affect the performance of the systems in which they are used as actuators. For example, when piezoceramic actuators are bonded with flexible structures for structural shape control purposes, errors of such magnitudes are not desirable. Thus, the nonlinear hysteretic input-output behavior leads to performance degradation of the system in the applications mentioned above. Hence, this work considers modeling of the hysteresis of a piezoceramic-actuated system with a view to develop model-based control algorithms to improve the performance of systems using these elements. Piezoceramic hysteresis has only recently been modeled effectively using the Preisach mathematical model. The system for which hystersis is modelled is a cantilever beam on which two piezoceramic actuators are bonded and the beam's tip displacement is used as the output parameter. The end purpose is shape control where input variations are quasi-static, hence only the static case of input variation is considered. The predicted results using the model obtained for this system, in general, are in agreement with the experimentally measured values. This work would pave the way for use of the model for active vibration control purposes, where the input variation is dynamic, using a variant of the Preisach model for the case of dynamic input variation.

  14. Results of NASA's First Autonomous Formation Flying Experiment: Earth Observing-1 (EO-1)

    NASA Technical Reports Server (NTRS)

    Folta, David C.; Hawkins, Albin; Bauer, Frank H. (Technical Monitor)

    2001-01-01

    NASA's first autonomous formation flying mission completed its primary goal of demonstrating an advanced technology called enhanced formation flying. To enable this technology, the Guidance, Navigation, and Control center at the Goddard Space Flight Center (GSFC) implemented a universal 3-axis formation flying algorithm in an autonomous executive flight code onboard the New Millennium Program's (NMP) Earth Observing-1 (EO-1) spacecraft. This paper describes the mathematical background of the autonomous formation flying algorithm and the onboard flight design and presents the validation results of this unique system. Results from functionality assessment through fully autonomous maneuver control are presented as comparisons between the onboard EO-1 operational autonomous control system called AutoCon(tm), its ground-based predecessor, and a standalone algorithm.

  15. Preliminary Results of NASA's First Autonomous Formation Flying Experiment: Earth Observing-1 (EO-1)

    NASA Technical Reports Server (NTRS)

    Folta, David; Hawkins, Albin

    2001-01-01

    NASA's first autonomous formation flying mission is completing a primary goal of demonstrating an advanced technology called enhanced formation flying. To enable this technology, the Guidance, Navigation, and Control center at the Goddard Space Flight Center has implemented an autonomous universal three-axis formation flying algorithm in executive flight code onboard the New Millennium Program's (NMP) Earth Observing-1 (EO-1) spacecraft. This paper describes the mathematical background of the autonomous formation flying algorithm and the onboard design and presents the preliminary validation results of this unique system. Results from functionality assessment and autonomous maneuver control are presented as comparisons between the onboard EO-1 operational autonomous control system called AutoCon(tm), its ground-based predecessor, and a stand-alone algorithm.

  16. Results of NASA's First Autonomous Formation Flying Experiment: Earth Observing-1 (EO-1)

    NASA Technical Reports Server (NTRS)

    Folta, David; Hawkins, Albin; Bauer, Frank (Technical Monitor)

    2002-01-01

    NASA's first autonomous formation flying mission completed its primary goal of demonstrating an advanced technology called enhanced formation flying. To enable this technology, the Flight Dynamics Analysis Branch at the Goddard Space Flight Center implemented a universal 3-axis formation flying algorithm in an autonomous executive flight code onboard the New Millennium Program's (NMP) Earth Observing-1 (EO-1) spacecraft. This paper describes the mathematical background of the autonomous formation flying algorithm, the onboard flight design and the validation results of this unique system. Results from fully autonomous maneuver control are presented as comparisons between the onboard EO-1 operational autonomous control system called AutoCon, its ground-based predecessor used in operations, and the original standalone algorithm. Maneuvers discussed encompass reactionary, routine formation maintenance, and inclination control. Orbital data is also examined to verify that all formation flying requirements were met.

  17. Results Of NASA's First Autonomous Formation Flying Experiment: Earth Observing-1 (EO-1)

    NASA Technical Reports Server (NTRS)

    Folta, David; Hawkins, Albin

    2002-01-01

    NASA's first autonomous formation flying mission completed its primary goal of demonstrating an advanced technology called Enhanced Formation Flying. To enable this technology, a team at the Goddard Space Flight Center implemented a universal 3-axis formation flying algorithm in an autonomous executive flight code onboard the New Millennium Program's (NMP) Earth Observing-1 (EO-1) spacecraft. This paper describes the mathematical background of the autonomous formation flying algorithm, the onboard flight design and the validation results of this unique system. Results from fully autonomous maneuver control are presented as comparisons between the onboard EO-1 operational autonomous control system called AutoCon(trademark), its ground-based predecessor used in operations, and the original standalone algorithm. Maneuvers discussed encompass reactionary, routine formation maintenance, and inclination control. Orbital data is also examined to verify that all formation flying requirements were met.

  18. Results of NASA's First Autonomous Formation Flying Experiment: Earth Observing-1 (EO-1)

    NASA Technical Reports Server (NTRS)

    Folta, David; Hawkins, Albin; Bauer, Frank (Technical Monitor)

    2002-01-01

    NASA's first autonomous formation flying mission completed its primary goal of demonstrating an advanced technology called enhanced formation flying. To enable this technology, the Flight Dynamics Analysis Branch at the Goddard Space Flight Center implemented a universal 3-axis formation flying algorithm in an autonomous executive flight code onboard the New Millennium Program's (NMP) Earth Observing-1 (EO-1) spacecraft. This paper describes the mathematical background of the autonomous formation flying algorithm, the onboard flight design and the validation results of this unique system. Results from fully autonomous maneuver control are presented as comparisons between the onboard EO-1 operational autonomous control system called AutoCon, its ground-based predecessor used in operations, and the original standalone algorithm. Maneuvers discussed encompass reactionary, routine formation maintenance, and inclination control. Orbital data is also examined to verify that all formation flying requirements were met.

  19. Results Of NASA's First Autonomous Formation Flying Experiment: Earth Observing-1 (EO-1)

    NASA Technical Reports Server (NTRS)

    Folta, David; Hawkins, Albin

    2002-01-01

    NASA's first autonomous formation flying mission completed its primary goal of demonstrating an advanced technology called Enhanced Formation Flying. To enable this technology, a team at the Goddard Space Flight Center implemented a universal 3-axis formation flying algorithm in an autonomous executive flight code onboard the New Millennium Program's (NMP) Earth Observing-1 (EO-1) spacecraft. This paper describes the mathematical background of the autonomous formation flying algorithm, the onboard flight design and the validation results of this unique system. Results from fully autonomous maneuver control are presented as comparisons between the onboard EO-1 operational autonomous control system called AutoCon(trademark), its ground-based predecessor used in operations, and the original standalone algorithm. Maneuvers discussed encompass reactionary, routine formation maintenance, and inclination control. Orbital data is also examined to verify that all formation flying requirements were met.

  20. 30/20 GHz satellite communication experiments using small earth stations in CS project

    NASA Astrophysics Data System (ADS)

    Saruwatari, T.; Uchida, K.; Matsumoto, K.; Iguchi, M.; Ohashi, H.; Isobe, S.

    Design features and the results of preliminary performance tests of small earth terminals (SETs) for the Japanese CS-II 20/30 GHz communications satellites are described. The tests covered 1- and 2-m antennas with 2 W IMPATT transmitters and FET receivers with less than 750 K noise temperature. Delta-M FM SCPC and MCPC data treatment and transmission equipment were used with the vehicle-mounted antennas. Measurements were made of the C/No and bit error rates and the effect of S/N performance on FM transmission. The stations received and transmitted newspaper data for publication and formed links of a computer network. The FM-SCPC link permitted broadcast of 220 channels between a central station and the small antennas. Communication could not be stabilized between small antennas during rainy conditions.

  1. Convection experiments in a centrifuge and the generation of plumes in a very viscous fluid. [for earth mantle models

    NASA Technical Reports Server (NTRS)

    Nataf, H.-C.; Hager, B. H.; Scott, R. F.

    1984-01-01

    In this paper, experiments are described for which inertial effects are negligible. A small aspect-ratio tank filled with a very viscous fluid (Pr = 10 to the 6th) is used to observe the behavior of convection for Rayleigh numbers up to 6.3 x 10 to the 5th. These high values are reached by conducting the experiment in a centrifuge which provides a 130-fold increase in apparent gravity. Rotational effects are small, but cannot be totally dismissed. In this geometry, thermal boundary layer instabilities are indeed observed, and are found to be very similar to their lower Prandtl number counterparts. It is tentatively concluded that once given a certain degree of 'vulnerability' convection can develop 'plume' like instabilities, even when the Prandtl number is infinite. The concept is applied to the earth's mantle and it is speculated that 'plumes' could well be the dominant mode of small-scale convection under the lithospheric plates.

  2. Role of reversible susceptibility in ferromagnetic hysteresis

    NASA Astrophysics Data System (ADS)

    Schneider, Carl S.

    2002-05-01

    An equation of state based upon saturation magnetization, Ms, coercive field, Hc, and the reversible susceptibility function of magnetization is proposed for ferromagnetic hysteresis. Reversible susceptibility divided by the initial susceptibility is the anisotropy function of magnetization, χr, ranging from one in the demagnetized state to zero at saturation, and varying with magnetic history. Its dependence on scaled magnetization, m=M/Ms on the interval (-1,1) varies with material, allowing characterization of anisotropy classes. Precise measurements have been made of reversible susceptibility, initial and saturate magnetization curves, and loops for Orthonol™, annealed 3% nickel steel and as-received 1018 steel, representing crystals, isotropic polycrystals and composite ferromagnets, respectively. Magnetization change is the product of the reversible susceptibility, change in the applied field and the cooperative function due to domain interactions. This function is 1+βm for the virgin curve with half this slope from any reversal, where β=Ms/XiHc is the hysteresis coefficient. Variation of β for 1018 steel is due to distributed coercivities, and causes sigmoid B(H) curves. In the scaled field representation, where h=H/Hc, the cooperative function is 1/(1-hχr), a hyperbolic field dependence smeared by the anisotropy function. Constant anisotropy causes closed hysteresis loops, while variable anisotropy causes creeping of cycled asymmetric loops. In ferromagnetism, 1/χ=1/χr-h, normal scaled reluctivity is reduced from its reversible value by the scaled field.

  3. Electroosmotic flow hysteresis for dissimilar ionic solutions

    PubMed Central

    Lim, An Eng; Lam, Yee Cheong

    2015-01-01

    Electroosmotic flow (EOF) with two or more fluids is commonly encountered in various microfluidics applications. However, no investigation has hitherto been conducted to investigate the hysteretic or flow direction-dependent behavior during the displacement flow of solutions with dissimilar ionic species. In this investigation, electroosmotic displacement flow involving dissimilar ionic solutions was studied experimentally through a current monitoring method and numerically through finite element simulations. The flow hysteresis can be characterized by the turning and displacement times; turning time refers to the abrupt gradient change of current-time curve while displacement time is the time for one solution to completely displace the other solution. Both experimental and simulation results illustrate that the turning and displacement times for a particular solution pair can be directional-dependent, indicating that the flow conditions in the microchannel are not the same in the two different flow directions. The mechanics of EOF hysteresis was elucidated through the theoretical model which includes the ionic mobility of each species, a major governing parameter. Two distinct mechanics have been identified as the causes for the EOF hysteresis involving dissimilar ionic solutions: the widening/sharpening effect of interfacial region between the two solutions and the difference in ion concentration distributions (and thus average zeta potentials) in different flow directions. The outcome of this investigation contributes to the fundamental understanding of flow behavior in microfluidic systems involving solution pair with dissimilar ionic species. PMID:25945139

  4. Constitutive modeling of contact angle hysteresis.

    PubMed

    Vedantam, Srikanth; Panchagnula, Mahesh V

    2008-05-15

    We introduce a phase field model of wetting of surfaces by sessile drops. The theory uses a two-dimensional non-conserved phase field variable to parametrize the Gibbs free energy of the three-dimensional system. Contact line tension and contact angle hysteresis arise from the gradient term in the free energy and the kinetic coefficient respectively. A significant advantage of this approach is in the constitutive specification of hysteresis. The advancing and receding angles of a surface, the liquid-vapor interfacial energy and three-phase line tension are the only required constitutive inputs to the model. We first simulate hysteresis on a smooth chemically homogeneous surface using this theory. Next we show that it is possible to study heterogeneous surfaces whose component surfaces are themselves hysteretic. We use this theory to examine the wetting of a surface containing a circular heterogeneous island. The contact angle for this case is found to be determined solely by the material properties at the contact line in accord with recent experimental data.

  5. A Unique Learning Experience Utilizing NASA's Space Photography of the Earth

    NASA Astrophysics Data System (ADS)

    Brumbaugh, Fred

    2002-01-01

    During the last decade, a highly specialized team with backgrounds in education and geography disciplines, including earth and environmental sciences, has developed a unique one-week workshop that trains classroom teachers (grade level five through undergraduate college) in the effective use of earth viewing photography for a variety of classroom situations and courses. The central focus of the workshop is to provide the teachers with the proper materials, skills, and expertise that will result in confident use of the selected course materials in their own classroom environment. Teachers attending the workshop receive a basic introduction to slide/photograph interpretation, as well as more detailed information for each of the images that are part of the workshop package. While the actual number of images/photographs may vary somewhat, the targeted number for the course is 75. That number can include regional images of the local area where the workshop is being conducted. The workshop is separated into three distinct but interrelated sections: content lectures; slide/photo interpretation sessions; and hands-on class demonstrations that include lesson plans and focus groups. For example, creative focus activities and teacher lessons are demonstrated for participants to show how the images/prints/overheads can be used in a classroom. Each teacher who attends the workshop receives two notebooks to take with them upon the completion of the course. Volume 1, the Image Notebook, contains slides, photographs, and accompanying captions. Volume 2, the Activity Notebook, consists of basic information (such as a glossary of photo interpretation terms), copies of content lecture notes and overhead transparencies, and all focus group activities and lessons. Teachers attending the workshop are also introduced to NASA websites to learn how to best use these dynamic and highly motivational tools to stimulate their students either through individual or group assignments.

  6. The PROCESS experiment: amino and carboxylic acids under Mars-like surface UV radiation conditions in low-earth orbit.

    PubMed

    Noblet, Audrey; Stalport, Fabien; Guan, Yuan Yong; Poch, Olivier; Coll, Patrice; Szopa, Cyril; Cloix, Mégane; Macari, Frédérique; Raulin, Francois; Chaput, Didier; Cottin, Hervé

    2012-05-01

    The search for organic molecules at the surface of Mars is a top priority of the next Mars exploration space missions: Mars Science Laboratory (NASA) and ExoMars (ESA). The detection of organic matter could provide information about the presence of a prebiotic chemistry or even biological activity on this planet. Therefore, a key step in interpretation of future data collected by these missions is to understand the preservation of organic matter in the martian environment. Several laboratory experiments have been devoted to quantifying and qualifying the evolution of organic molecules under simulated environmental conditions of Mars. However, these laboratory simulations are limited, and one major constraint is the reproduction of the UV spectrum that reaches the surface of Mars. As part of the PROCESS experiment of the European EXPOSE-E mission on board the International Space Station, a study was performed on the photodegradation of organics under filtered extraterrestrial solar electromagnetic radiation that mimics Mars-like surface UV radiation conditions. Glycine, serine, phthalic acid, phthalic acid in the presence of a mineral phase, and mellitic acid were exposed to these conditions for 1.5 years, and their evolution was determined by Fourier transform infrared spectroscopy after their retrieval. The results were compared with data from laboratory experiments. A 1.5-year exposure to Mars-like surface UV radiation conditions in space resulted in complete degradation of the organic compounds. Half-lives between 50 and 150 h for martian surface conditions were calculated from both laboratory and low-Earth orbit experiments. The results highlight that none of those organics are stable under low-Earth orbit solar UV radiation conditions.

  7. Deformation Hysteresis of Electrohydrodynamic Patterning on a Thin Polymer Film.

    PubMed

    Yang, Qingzhen; Li, Ben Q; Tian, Hongmiao; Li, Xiangming; Shao, Jinyou; Chen, Xiaoliang; Xu, Feng

    2016-07-13

    Electrohydrodynamic patterning is a technique that enables micro/nanostructures via imposing an external voltage on thin polymer films. In this investigation, we studied the electrohydrodynamic patterning theoretically and experimentally, with special interest focused on the equilibrium state. It is found that the equilibrium structure height increases with the voltage. In addition, we have observed, and believe it to be the first time, a hysteresis phenomenon exists in the relationship between the voltage and structure height. With an increase in the voltage, a critical value (the first critical voltage) is noticed, above which the polymer film would increase dramatically until it comes into contact with the template. However, with a decrease in the voltage, a smaller voltage (the second critical voltage) is needed to detach the polymer from the template. The mismatch of the first and second critical voltages distorts the voltage-structure height curve into an "S" shape. Such a phenomenon is verified for three representative templates and also by experiments. Furthermore, the effects of some parameters (e.g., polymer film thickness and dielectric constant) on this hysteresis phenomenon are also discussed.

  8. Computational micromagnetic study of particulate media hysteresis and recording

    NASA Astrophysics Data System (ADS)

    Seberino, Christian

    2000-11-01

    A description of the micromagnetic theory, algorithms, computer software and computer hardware built and used to study particulate media particles, hysteresis and recording is first provided. This includes a derivation and analysis of the modified version of the Fast Multipole Method used in this dissertation. Results will then be presented on particulate media particle nucleation field dependence on particle shape, particle aspect ratio, ferromagnetic exchange energy and external magnetic field angle. Results on the discretization necessary to accurately model a particle will also be provided. The reversal mode of a particle will be simulated and analyzed. Simulated longitudinal and transverse hysteresis loops will be presented. Results will also be presented on particulate media coercivity and squareness dependence on volumetric packing fraction. Simulated recorded transition results will be given as well as total power spectra results for AC and DC erased particulate media. Numerical results will be compared to experimental data and analytical theories. Advice is provided on how to build a personal supercomputer like the one used in the numerical experiments of this dissertation.

  9. Raduga experiment: Multizonal photographing the Earth from the Soyuz-22 spacecraft

    NASA Technical Reports Server (NTRS)

    Ziman, Y.; Chesnokov, Y.; Dunayev, B.; Aksenov, V.; Bykovskiy, V.; Ioaskhim, R.; Myuller, K.; Choppe, V.; Volter, V.

    1980-01-01

    The main results of the scientific research and 'Raduga' experiment are reported. Technical parameters are presented for the MKF-6 camera and the MSP-4 projector. Characteristics of the obtained materials and certain results of their processing are reported.

  10. Low Earth Orbital Mission Aboard the Space Test Experiments Platform (STEP-3)

    NASA Technical Reports Server (NTRS)

    Brinza, David E.

    1992-01-01

    A discussion of the Space Active Modular Materials Experiments (SAMMES) is presented in vugraph form. The discussion is divided into three sections: (1) a description of SAMMES; (2) a SAMMES/STEP-3 mission overview; and (3) SAMMES follow on efforts. The SAMMES/STEP-3 mission objectives are as follows: assess LEO space environmental effects on SDIO materials; quantify orbital and local environments; and demonstrate the modular experiment concept.

  11. Features of re-entrant albedo deuteron trajectories in near Earth orbit with PAMELA experiment

    NASA Astrophysics Data System (ADS)

    Koldobskiy, S. A.; Adriani, O.; Barbarino, G. C.; Bazilevskaya, G. A.; Bellotti, R.; Boezio, M.; Bogomolov, E. A.; Bongi, M.; Bonvicini, V.; Bottai, S.; Bruno, A.; Cafagna, F.; Campana, D.; Carlson, P.; Casolino, M.; Castellini, G.; De Donato, C.; De Santis, C.; De Simone, N.; Di Felice, V.; Formato, V.; Galper, A. M.; Karelin, A. V.; Koldashov, S. V.; Krutkov, S. Y.; Kvashnin, A. N.; Leonov, AA; Malakhov, V.; Marcelli, L.; Martucci, M.; Mayorov, A. G.; Menn, W.; Mergè, M.; Mikhailov, V. V.; Mocchiutti, E.; Monaco, A.; Mori, N.; Munini, R.; Osteria, G.; Palma, F.; Panico, B.; Papini, P.; Pearce, M.; Picozza, P.; Ricci, M.; Ricciarini, S. B.; Sarkar, R.; Scotti, V.; Simon, M.; Sparvoli, R.; Spillantini, P.; Stozhkov, Y. I.; Vacchi, A.; Vannuccini, E.; Vasilyev, GI; Voronov, S. A.; Yurkin, Y. T.; Zampa, G.; Zampa, N.

    2016-02-01

    The results of trajectory reconstruction for re-entrant albedo deuteron fluxes obtained in the PAMELA experiment are presented in this work. PAMELA is an international experiment aimed on measurements of cosmic ray particle fluxes in wide energy range. In particular, analysis of PAMELA data gives possibility to identify deuterons. Classification of re-entrant albedo deuterons with energies from 70 to 400 MeV/nucleon depending on theirs reconstructed lifetimes and generation zones is presented here at first time.

  12. Power Beaming for Space-Based Electricity on Earth: Near-Term Experiments with Radars, Lasers and Satellites

    NASA Astrophysics Data System (ADS)

    Hoffert, E.; Soukup, P.; Hoffert, M.

    2004-12-01

    Power beaming experiments thus far have been done over distances close enough where receiver apertures approximately the same diameter as transmitters can capture most of the beam (the "near- field"). The best experimentally verified wireless power transmission DC-to-DC efficiencies are 54% for a microwave transmission measured over a short distance; the longest range wireless power transmission stands at 1.6 km in 1975 (Brown, 1998; Dickinson, 1975, 2002). The next logical step is longer-range, "far-field" power beaming, particularly Space-to-Earth, or its reciprocal, Earth-to-Space, to validate beam propagation models and establish a solid experimental basis for power transmission through the atmosphere. To minimize costs, we propose adapting ground-based microwave transmitters designed for radio astronomy (Arecibo), planetary communications (NASA Deep Space Network) and detection (USAF Space Surveillance Network) for Earth-to-Space beaming tests. The receiving end could, in principle, be an NRO satellite antenna reportedly orbiting today and/or rectennas unfurled by the International Space Station (ISS). Laser SSP has lower transmission efficiency; but smaller, more flexible, and potentially cheaper components make it worth exploring. Lasers require smaller components because diffraction effects are less at optical than at microwave wavelengths The Air Force Maui Optical Station (AMOS), with facilities for accurately firing lasers through ground-based telescopes with adaptive optics at targets in space, appears ideal for laser beaming tests in conjunction with orbiting PV arrays targets. Platforms like the ISS and/or GEO communication satellites may likewise have (or could easily have) lightweight PV arrays capable of converting light to DC for end-to-end power efficiency tests. If successful, these experiments might be followed with impressive demonstrations of SSP technology such as illumination of lamps visible from Earth's surface on orbiting satellites, or

  13. Selenium Sequestration in a Cationic Layered Rare Earth Hydroxide: A Combined Batch Experiments and EXAFS Investigation.

    PubMed

    Zhu, Lin; Zhang, Linjuan; Li, Jie; Zhang, Duo; Chen, Lanhua; Sheng, Daopeng; Yang, Shitong; Xiao, Chengliang; Wang, Jianqiang; Chai, Zhifang; Albrecht-Schmitt, Thomas E; Wang, Shuao

    2017-08-01

    Selenium is of great concern owing to its acutely toxic characteristic at elevated dosage and the long-term radiotoxicity of (79)Se. The contents of selenium in industrial wastewater, agricultural runoff, and drinking water have to be constrained to a value of 50 μg/L as the maximum concentration limit. We reported here the selenium uptake using a structurally well-defined cationic layered rare earth hydroxide, Y2(OH)5Cl·1.5H2O. The sorption kinetics, isotherms, selectivity, and desorption of selenite and selenate on Y2(OH)5Cl·1.5H2O at pH 7 and 8.5 were systematically investigated using a batch method. The maximum sorption capacities of selenite and selenate are 207 and 124 mg/g, respectively, both representing the new records among those of inorganic sorbents. In the low concentration region, Y2(OH)5Cl·1.5H2O is able to almost completely remove selenium from aqueous solution even in the presence of competitive anions such as NO3(-), Cl(-), CO3(2-), SO4(2-), and HPO4(2-). The resulting concentration of selenium is below 10 μg/L, well meeting the strictest criterion for the drinking water. The selenate on loaded samples could be desorbed by rinsing with concentrated noncomplexing NaCl solutions whereas complexing ligands have to be employed to elute selenite for the material regeneration. After desorption, Y2(OH)5Cl·1.5H2O could be reused to remove selenate and selenite. In addition, the sorption mechanism was unraveled by the combination of EDS, FT-IR, Raman, PXRD, and EXAFS techniques. Specifically, the selenate ions were exchanged with chloride ions in the interlayer space, forming outer-sphere complexes. In comparison, besides anion exchange mechanism, the selenite ions were directly bound to the Y(3+) center in the positively charged layer of [Y2(OH)5(H2O)](+) through strong bidentate binuclear inner-sphere complexation, consistent with the observation of the higher uptake of selenite over selenate. The results presented in this work confirm that the

  14. Measurements of the earth radiation budget from satellites during the first GARP global experiment

    NASA Technical Reports Server (NTRS)

    Vonder Haar, T. H.; Campbell, G. G.; Smith, E. A.; Arking, A.; Coulson, K.; Hickey, J.; House, F.; Ingersoll, A.; Jacobowitz, H.; Smith, L.

    1981-01-01

    Radiation budget data (which will aid in climate model development) and solar constant measurements (both to be used for the study of long term climate change and interannual seasonal weather variability) are presented, obtained during Nimbus-6 and Nimbus-7 satellite flights, using wide-field-of-view, scanner, and black cavity detectors. Data on the solar constant, described as a function of the date of measurement, are given. The unweighed mean amounts to 1377 + or - 20 per sq Wm, with a standard deviation of 8 per sq Wm. The new solar data are combined with earlier measurements, and it is suggested that the total absolute energy output of the sun is a minimum at 'solar maximum' and vice versa. Attention is given to the measurements of the net radiation budget, the planetary albedo, and the infrared radiant exitance. The annual and semiannual cycles of normal variability explain most of the variance of energy exchange between the earth and space. Examination of separate ocean and atmospheric energy budgets implies a net continent-ocean region energy exchange.

  15. Untangling Perceptual Memory: Hysteresis and Adaptation Map into Separate Cortical Networks

    PubMed Central

    Schwiedrzik, Caspar M.; Ruff, Christian C.; Lazar, Andreea; Leitner, Frauke C.; Singer, Wolf; Melloni, Lucia

    2014-01-01

    Perception is an active inferential process in which prior knowledge is combined with sensory input, the result of which determines the contents of awareness. Accordingly, previous experience is known to help the brain “decide” what to perceive. However, a critical aspect that has not been addressed is that previous experience can exert 2 opposing effects on perception: An attractive effect, sensitizing the brain to perceive the same again (hysteresis), or a repulsive effect, making it more likely to perceive something else (adaptation). We used functional magnetic resonance imaging and modeling to elucidate how the brain entertains these 2 opposing processes, and what determines the direction of such experience-dependent perceptual effects. We found that although affecting our perception concurrently, hysteresis and adaptation map into distinct cortical networks: a widespread network of higher-order visual and fronto-parietal areas was involved in perceptual stabilization, while adaptation was confined to early visual areas. This areal and hierarchical segregation may explain how the brain maintains the balance between exploiting redundancies and staying sensitive to new information. We provide a Bayesian model that accounts for the coexistence of hysteresis and adaptation by separating their causes into 2 distinct terms: Hysteresis alters the prior, whereas adaptation changes the sensory evidence (the likelihood function). PMID:23236204

  16. Untangling perceptual memory: hysteresis and adaptation map into separate cortical networks.

    PubMed

    Schwiedrzik, Caspar M; Ruff, Christian C; Lazar, Andreea; Leitner, Frauke C; Singer, Wolf; Melloni, Lucia

    2014-05-01

    Perception is an active inferential process in which prior knowledge is combined with sensory input, the result of which determines the contents of awareness. Accordingly, previous experience is known to help the brain "decide" what to perceive. However, a critical aspect that has not been addressed is that previous experience can exert 2 opposing effects on perception: An attractive effect, sensitizing the brain to perceive the same again (hysteresis), or a repulsive effect, making it more likely to perceive something else (adaptation). We used functional magnetic resonance imaging and modeling to elucidate how the brain entertains these 2 opposing processes, and what determines the direction of such experience-dependent perceptual effects. We found that although affecting our perception concurrently, hysteresis and adaptation map into distinct cortical networks: a widespread network of higher-order visual and fronto-parietal areas was involved in perceptual stabilization, while adaptation was confined to early visual areas. This areal and hierarchical segregation may explain how the brain maintains the balance between exploiting redundancies and staying sensitive to new information. We provide a Bayesian model that accounts for the coexistence of hysteresis and adaptation by separating their causes into 2 distinct terms: Hysteresis alters the prior, whereas adaptation changes the sensory evidence (the likelihood function).

  17. Free Space Laser Communication Experiments from Earth to the Lunar Reconnaissance Orbiter in Lunar Orbit

    NASA Technical Reports Server (NTRS)

    Sun, Xiaoli; Skillman, David R.; Hoffman, Evan D.; Mao, Dandan; McGarry, Jan F.; Zellar, Ronald S.; Fong, Wai H; Krainak, Michael A.; Neumann, Gregory A.; Smith, David E.

    2013-01-01

    Laser communication and ranging experiments were successfully conducted from the satellite laser ranging (SLR) station at NASA Goddard Space Flight Center (GSFC) to the Lunar Reconnaissance Orbiter (LRO) in lunar orbit. The experiments used 4096-ary pulse position modulation (PPM) for the laser pulses during one-way LRO Laser Ranging (LR) operations. Reed-Solomon forward error correction codes were used to correct the PPM symbol errors due to atmosphere turbulence and pointing jitter. The signal fading was measured and the results were compared to the model.

  18. Atmospheric X-ray emission experiment for shuttle. [earth atmosphere - radiation counters

    NASA Technical Reports Server (NTRS)

    Goldberg, R. A.; Hallam, K. L.; Emming, J. G.

    1975-01-01

    An experiment designed to measure the spatial, temporal, and energy distribution of X-ray aurorae produced by precipitating electrons, is presented. The experiment will provide vital data on solar-terrestrial relationships that may lead to defining the transfer mechanism that causes certain terrestrial weather events and climatological behavior. An instrument concept is discussed, and is based on a spatially sensitive multiwire proportional counter, combined with collimators to produce X-ray images of the aurorae. An instrument pointing system, on which the counter can be mounted, will provide the required altitude control, and can be operated by a Spacelab payload specialist for full control over its observing and data taking modes.

  19. Free space laser communication experiments from Earth to the Lunar Reconnaissance Orbiter in lunar orbit.

    PubMed

    Sun, Xiaoli; Skillman, David R; Hoffman, Evan D; Mao, Dandan; McGarry, Jan F; McIntire, Leva; Zellar, Ronald S; Davidson, Frederic M; Fong, Wai H; Krainak, Michael A; Neumann, Gregory A; Zuber, Maria T; Smith, David E

    2013-01-28

    Laser communication and ranging experiments were successfully conducted from the satellite laser ranging (SLR) station at NASA Goddard Space Flight Center (GSFC) to the Lunar Reconnaissance Orbiter (LRO) in lunar orbit. The experiments used 4096-ary pulse position modulation (PPM) for the laser pulses during one-way LRO Laser Ranging (LR) operations. Reed-Solomon forward error correction codes were used to correct the PPM symbol errors due to atmosphere turbulence and pointing jitter. The signal fading was measured and the results were compared to the model.

  20. Resting Lightly on Mother Earth: The Aboriginal Experience in Urban Educational Settings.

    ERIC Educational Resources Information Center

    Ward, Angela; Bouvier, Rita

    This book examines the differential educational experiences of Aboriginal peoples in urban centers--primarily in Canada, but also in Australia and the United States. Major themes of the book are maintenance of individual and collective Aboriginal identity, the impact on that identity of disconnection from the land, spirituality as the key to…

  1. Shaker Table Experiments with Rare Earth Elements Sorption from Geothermal Brine

    DOE Data Explorer

    Gary Garland

    2015-07-21

    This dataset described shaker table experiments ran with sieved -50 +100 mesh media #1 in brine #1 that have 2ppm each of the 7 REE metals at different starting pH's of 3.5, 4.5, and 5.5. The experimental conditions are 2g media to 150mL of REE solution, at 70C.

  2. Apollo-Soyuz Pamphlet No. 5: The Earth from Orbit. Apollo-Soyuz Experiments in Space.

    ERIC Educational Resources Information Center

    Page, Lou Williams; Page, Thornton

    This booklet is the fifth in a series of nine that describe the Apollo-Soyuz mission and experiments. This set is designed as a curriculum supplement for high school and college teachers, supervisors, curriculum specialists, textbook writers, and the general public. These booklets provide sources of ideas, examples of the scientific method,…

  3. Density hysteresis of heavy water confined in a nanoporous silica matrix

    SciTech Connect

    Zhang, Yang; Faraone, Antonio; Kamitakahara, William; Liu, Kao-Hsiang; Mou, Chung-Yuan; Leao, Juscelino B; Chang, Sung C; Chen, Sow-hsin H

    2011-01-01

    A neutron scattering technique was developed to measure the density of heavy water confined in a nanoporous silica matrix in a temperature-pressure range, from 300 to 130 K and from 1 to 2,900 bars, where bulk water will crystalize. We observed a prominent hysteresis phenomenon in the measured density profiles between warming and cooling scans above 1,000 bars. We inter- pret this hysteresis phenomenon as support (although not a proof) of the hypothetical existence of a first-order liquid liquid phase transition of water that would exist in the macroscopic system if crystallization could be avoided in the relevant phase region. Moreover, the density data we obtained for the confined heavy water under these conditions are valuable to large communities in biology and earth and planetary sciences interested in phenomena in which nanometer-sized water layers are involved.

  4. Density hysteresis of heavy water confined in a nanoporous silica matrix

    PubMed Central

    Zhang, Yang; Faraone, Antonio; Kamitakahara, William A.; Liu, Kao-Hsiang; Mou, Chung-Yuan; Leão, Juscelino B.; Chang, Sung; Chen, Sow-Hsin

    2011-01-01

    A neutron scattering technique was developed to measure the density of heavy water confined in a nanoporous silica matrix in a temperature-pressure range, from 300 to 130 K and from 1 to 2,900 bars, where bulk water will crystalize. We observed a prominent hysteresis phenomenon in the measured density profiles between warming and cooling scans above 1,000 bars. We interpret this hysteresis phenomenon as support (although not a proof) of the hypothetical existence of a first-order liquid–liquid phase transition of water that would exist in the macroscopic system if crystallization could be avoided in the relevant phase region. Moreover, the density data we obtained for the confined heavy water under these conditions are valuable to large communities in biology and earth and planetary sciences interested in phenomena in which nanometer-sized water layers are involved. PMID:21746898

  5. Lander radio science experiment with a direct link between Mars and the Earth

    NASA Astrophysics Data System (ADS)

    Le Maistre, Sébastien; Rosenblatt, Pascal; Rivoldini, Attilio; Dehant, Véronique; Marty, Jean-Charles; Karatekin, Ozgür

    2012-08-01

    Mars' Orientation and rotation Parameters (called here MOP): precession, nutation, polar motion and length of day (LOD) variations, are related to the interior of the planet as well as to the dynamics of its atmosphere. The MOP can be determined using the Doppler shift on radio signal data due to the motion of a probe landed on Mars relative to tracking stations on Earth. In this paper we perform numerical simulations for assessing the precision on the determination of the MOP using Direct-To-Earth (DTE) X-band Doppler measurements for a nearly equatorial lander. We then discuss how a better knowledge of the MOP could improve our understanding on the interior structure. The sensitivity of such a DTE radio link to these rotation parameters is first investigated. This shows that the latitude of the landing site must be higher than 20° to detect the Chandler Wobble component of the polar motion in DTE Doppler data and must be at least 40° to get tight constraints on it. It is found that the precision in the determination of the seasonal LOD variations will be significantly improved after about 350 days of operation, reaching the 5% level after 550 days, thereby better constraining the CO2 mass budget in the Martian atmosphere and ice caps. The current precision in the precession rate (25 milliarcsecond (mas) per year) will be matched after 150 days of mission. An uncertainty of less than 5 mas/year will be reached after 700 days, improving the precision on the polar moment of inertia by a factor of five. The precision on the determination of the amplitudes of nutation is estimated at a few mas after one Martian year of mission (about 12 mas on the prograde/retrograde semi and terannual amplitudes) allowing for the detection of the contribution expected from the liquid core. Considering Mars with a liquid core in accordance with recent geodesic measurements, the Free-Core-Nutation (FCN) period is estimated with a precision of less than 10 days after 550 days of

  6. Measurement of the deflection of cosmic-ray electrons in the energy range 75-250 GeV by the Earth's magnetic field with the PAMELA experiment

    SciTech Connect

    Karelin, A. V. Voronov, S. A.; Galper, A. M.; Malakhov, V. V.; Mikhailov, V. V.

    2013-07-15

    The deflection of electrons in the Earth's magnetic field in the energy range 75-250 GeV (the so-called east-west effect) has been measured with the PAMELA satellite-borne experiment. The results are presented for various L-shells. The data obtained can be used to construct mathematical models that describe the structure of the Earth's magnetic field and to refine the already existing models. These data can also be directly applied to estimate the positron fraction in cosmic-ray electron fluxes both in the PAMELA experiment and in other satellite-borne experiments.

  7. Rare Earth Element Partition Coefficients During High-Grade Metamorphism: Experiments, Realities, And Large Datasets

    NASA Astrophysics Data System (ADS)

    Taylor, R.; Clark, C.; Kylander-Clark, A. R.; Hacker, B. R.

    2015-12-01

    For 15 years rare earth element (REE) partitioning between zircon and garnet has facilitated the coupling of U-Pb ages to metamorphism, particularly in the granulite facies. The combination of in situ analysis and rapid data acquisition, particularly through combined techniques such as laser ablation split stream (LASS), means that complex terranes can be interrogated with increasing detail. However this detail provided by large datasets must also be combined with an understanding of the processes involved, for example the relative mobility of the REE, Ti, U and Pb within zircon grains that have withstood intense P-T conditions to varying degrees. Care must also be taken in identifying open system conditions, for example the presence or passage of partial melts that result in non-equilibrium, or very localised equilibrium, between the phases of interest. Visualisation of REE partition coefficients (DREE) becomes more complex with large datasets particularly when dealing with variably recrystallised zircon grains or multiple generations of garnet. Simple methods of visualising the important partitioning parameters identify temperature trends in experimental datasets [1, 2]. These trends can be used as clear indicators of zircon growing or recrystallizing in the presence of stable garnet and may be used as thermometers for zircon growth and for the identification of thermal peaks. Investigation of zircon-garnet DREE values in both long-lived high grade terranes (e.g. S. India), and complex polymetamorphic terranes (e.g. Enderby Land, E. Antarctica) provides insight into how partitioning information can be carefully interrogated, by looking at systematic or erratic variations from experimental data, even when dealing with issues such as variably recrystallised zircon and melt migration. Rubatto and Hermann, (2007). Chemical Geology. Taylor et al., (2015). Journal Metamorphic Geology.

  8. Analysis of data from the plasma composition experiment on the International Sun-Earth Explorer (ISEE 1)

    NASA Astrophysics Data System (ADS)

    Lennartsson, O. W.

    1994-05-01

    The Lockheed plasma composition experiment on the ISEE 1 spacecraft has provided one of the largest and most varied sets of data on earth's energetic plasma environment, covering both the solar wind, well beyond the bow shock, and the near equatorial magnetosphere to a distance of almost 23 earth radii. This report is an overview of the last four years of data analysis and archiving. The archiving for NSSDC includes most data obtained during the initial 28-months of instrument operation, from early November 1977 through the end of February 1980. The data products are a combination of spectra (mass and energy angle) and velocity moments. A copy of the data user's guide and examples of the data products are attached as appendix A. The data analysis covers three major areas: solar wind ions upstream and downstream of the day side bowshock, especially He(++) ions; terrestrial ions flowing upward from the auroral regions, especially H(+), O(+), and He(+) ions; and ions of both solar and terrestrial origins in the tail plasma sheet and lobe regions. Copies of publications are attached.

  9. An application of miniscale experiments on Earth to refine microgravity analysis of adiabatic multiphase flow in space

    NASA Technical Reports Server (NTRS)

    Rothe, Paul H.; Martin, Christine; Downing, Julie

    1994-01-01

    Adiabatic two-phase flow is of interest to the design of multiphase fluid and thermal management systems for spacecraft. This paper presents original data and unifies existing data for capillary tubes as a step toward assessing existing multiphase flow analysis and engineering software. Comparisons of theory with these data once again confirm the broad accuracy of the theory. Due to the simplicity and low cost of the capillary tube experiments, which were performed on earth, we were able to closely examine for the first time a flow situation that had not previously been examined appreciably by aircraft tests. This is the situation of a slug flow at high quality, near transition to annular flow. Our comparison of software calculations with these data revealed overprediction of pipeline pressure drop by up to a factor of three. In turn, this finding motivated a reexamination of the existing theory, and then development of a new analytical and is in far better agreement with the data. This sequence of discovery illustrates the role of inexpensive miniscale modeling on earth to anticipate microgravity behavior in space and to complete and help define needs for aircraft tests.

  10. Analysis of data from the plasma composition experiment on the International Sun-Earth Explorer (ISEE 1)

    NASA Technical Reports Server (NTRS)

    Lennartsson, O. W.

    1994-01-01

    The Lockheed plasma composition experiment on the ISEE 1 spacecraft has provided one of the largest and most varied sets of data on earth's energetic plasma environment, covering both the solar wind, well beyond the bow shock, and the near equatorial magnetosphere to a distance of almost 23 earth radii. This report is an overview of the last four years of data analysis and archiving. The archiving for NSSDC includes most data obtained during the initial 28-months of instrument operation, from early November 1977 through the end of February 1980. The data products are a combination of spectra (mass and energy angle) and velocity moments. A copy of the data user's guide and examples of the data products are attached as appendix A. The data analysis covers three major areas: solar wind ions upstream and downstream of the day side bowshock, especially He(++) ions; terrestrial ions flowing upward from the auroral regions, especially H(+), O(+), and He(+) ions; and ions of both solar and terrestrial origins in the tail plasma sheet and lobe regions. Copies of publications are attached.

  11. (Re)engineering Earth System Models to Expose Greater Concurrency for Ultrascale Computing: Practice, Experience, and Musings

    NASA Astrophysics Data System (ADS)

    Mills, R. T.

    2014-12-01

    As the high performance computing (HPC) community pushes towards the exascale horizon, the importance and prevalence of fine-grained parallelism in new computer architectures is increasing. This is perhaps most apparent in the proliferation of so-called "accelerators" such as the Intel Xeon Phi or NVIDIA GPGPUs, but the trend also holds for CPUs, where serial performance has grown slowly and effective use of hardware threads and vector units are becoming increasingly important to realizing high performance. This has significant implications for weather, climate, and Earth system modeling codes, many of which display impressive scalability across MPI ranks but take relatively little advantage of threading and vector processing. In addition to increasing parallelism, next generation codes will also need to address increasingly deep hierarchies for data movement: NUMA/cache levels, on node vs. off node, local vs. wide neighborhoods on the interconnect, and even in the I/O system. We will discuss some approaches (grounded in experiences with the Intel Xeon Phi architecture) for restructuring Earth science codes to maximize concurrency across multiple levels (vectors, threads, MPI ranks), and also discuss some novel approaches for minimizing expensive data movement/communication.

  12. Hysteresis and the length dependence of calcium sensitivity in chemically skinned rat cardiac muscle.

    PubMed Central

    Harrison, S M; Lamont, C; Miller, D J

    1988-01-01

    1. The relationship between pCa (-log10[Ca2+]) and steady-state isometric tension has been investigated in saponin- or Triton-treated (chemically 'skinned') cardiac muscle of rat. 2. Hysteresis exists in the relationship such that the muscle is less sensitive to Ca2+ during increasing activation (as [Ca2+] is stepped upward) than during reducing activation (as [Ca2+] is stepped downward). 3. The extent of the hysteresis is insensitive to interventions that increase overall calcium sensitivity by chemical means, such as caffeine, carnosine or increased pH. 4. The extent of the hysteresis is sensitive to sarcomere length. The phenomenon is virtually absent above sarcomere lengths of about 2.2-2.3 microns but becomes progressively greater at shorter sarcomere lengths. 5. The effect of sarcomere length on calcium sensitivity is restricted to the upward-going (increasing activation) part of the pCa-tension loop below 2.2 microns. The downward-going (decreasing activation) part of the hysteretic relationship is virtually unaffected by sarcomere length up to 2.2 microns. 6. Significant alterations in sarcomere length do not occur during tension development in the experiments described here: the phenomenon is not attributable to experimental artifacts of this kind. 7. Hysteresis develops sufficiently rapidly to be consistent with a physiological relevance during the normal heart beat. 8. The effects of sarcomere length show that the phenomenon is not due to force per se since, for example, greater peak force produces less hysteresis as sarcomere length is increased towards 2.2 microns. 9. Tonicity increase (by high-molecular-weight dextran), which shrinks the myofilament lattice, increases calcium sensitivity but reduces the effect of sarcomere length on calcium sensitivity. 10. The results suggest that lattice shrinkage is the mechanism which accounts for hysteresis in, and the sarcomere length dependence of, calcium sensitivity in cardiac muscle. Images Fig. 1 Fig. 11

  13. Theory of plasma contactors in ground-based experiments and low earth orbit

    NASA Technical Reports Server (NTRS)

    Gerver, M. J.; Hastings, D. E.; Oberhardt, M. R.

    1990-01-01

    An examination of several models of electron collection by plasma contactors leads to a definition of the range of validity and applicability for each model. It is noted that most present ground-based experiments are of limited relevance to space applications of plasma contactors, since they operate in a regime where the magnetic field and effective collisions are at most only marginally important. An exception is the experiment of Stenzel and Urrutia (1986), which examined a plasma whose electron Larmor radius was small by comparison to the scale of the potential, and in which the anomalous transport of electrons across the magnetic field was important. The enhanced electron current was not continuous in time, but occurred in periodic bursts as the instabilities periodically emerged, saturated, and decayed.

  14. The SORA Experiment: Testing the Subsurface Penetration Radar SHARAD on the Earth

    NASA Astrophysics Data System (ADS)

    Flamini, E.; Ori, G.; Seu, R.; Angrilli, F.

    2006-12-01

    Two subsurface penetrating radars are currently working on Mars: MARSIS and SHARAD. MARSIS displays deep penetration and low resolution and SHARAD exhibits low penetration and high resolution. SHARAD is able to depicts relatively detailed internal features and stratal patterns. In order to fully understand the SHARAD capability, the data interpretations, and possible future developments the Italian Space Agency is organising an experiment to fly a SHARAD model in a stratospheric ballon. The experiment will consists in a no-space qualified model of SHARAD installed on a stratospheric balloon flying over the Arctic from the Spitsbergen. The fly will circumnavigate the Arctic passing over Greenland, the Canadian Arctic Arcipelago, New Zelmya and probably Spitsbergen itself. The fly altitude will be 35000 m and the cruise will last about a week. The investigated aareas includes ice sheets, glaciers, permafrost areas, plutonic to sedimentary rocks. And sedimentary natural environments. Sea ice will be probably too thin to be detected by the instrument. Frequency will be chosen to mimic the SAHARD ones. The experiment is planned for June 2007 with backup on September 2007 or June 2008.

  15. The ClearEarth Project: Preliminary Findings from Experiments in Applying the CLEARTK NLP Pipeline and Annotation Tools Developed for Biomedicine to the Earth Sciences

    NASA Astrophysics Data System (ADS)

    Duerr, R.; Thessen, A.; Jenkins, C. J.; Palmer, M.; Myers, S.; Ramdeen, S.

    2016-12-01

    The ability to quickly find, easily use and effortlessly integrate data from a variety of sources is a grand challenge in Earth sciences, one around which entire research programs have been built. A myriad of approaches to tackling components of this challenge have been demonstrated, often with some success. Yet finding, assessing, accessing, using and integrating data remains a major challenge for many researchers. A technology that has shown promise in nearly every aspect of the challenge is semantics. Semantics has been shown to improve data discovery, facilitate assessment of a data set, and through adoption of the W3C's Linked Data Platform to have improved data integration and use at least for data amenable to that paradigm. Yet the creation of semantic resources has been slow. Why? Amongst a plethora of other reasons, it is because semantic expertise is rare in the Earth and Space sciences; the creation of semantic resources for even a single discipline is labor intensive and requires agreement within the discipline; best practices, methods and tools for supporting the creation and maintenance of the resources generated are in flux; and the human and financial capital needed are rarely available in the Earth sciences. However, other fields, such as biomedicine, have made considerable progress in these areas. The NSF-funded ClearEarth project is adapting the methods and tools from these communities for the Earth sciences in the expectation that doing so will enhance progress and the rate at which the needed semantic resources are created. We discuss progress and results to date, lessons learned from this adaptation process, and describe our upcoming efforts to extend this knowledge to the next generation of Earth and data scientists.

  16. Skylab program earth resouces experiment package. Volume 4: Sensor performance evaluation (S193 R/S). [radiometer/scatterometer

    NASA Technical Reports Server (NTRS)

    Kenney, G. P.

    1975-01-01

    The results of the sensor performance evaluation of the 13.9 GHz radiometer/scatterometer, which was part of the earth resources experiment package on Skylab. Findings are presented in the areas of housekeeping parameters, antenna gain and scanning performance, dynamic range, linearity, precision, resolution, stability, integration time, and transmitter output. Supplementary analyses covering performance anomalies, data stream peculiarities, aircraft sensor data comparisons, scatterometer saturation characteristics, and RF heating effects are reported. Results of the evaluation show that instrument performance was generally as expected, but capability degradations were observed to result from three major anomalies. Conclusions are drawn from the evaluation results, and recommendations for improving the effectiveness of a future program are offered. An addendum describes the special evaluation techniques developed and applied in the sensor performance evaluation tasks.

  17. An Experiment to Evaluate Skylab Earth Resources Sensors for Detection of the Gulf Stream. [Straits of Florida

    NASA Technical Reports Server (NTRS)

    Maul, G. A. (Principal Investigator); Gordon, H. R.; Baig, S. R.; Mccaslin, M.; Devivo, R. J.

    1976-01-01

    The author has identified the following significant results. An experiment to evaluate the Skylab earth resources package for observing ocean currents was performed in the Straits of Florida in January 1974. Data from the S190 photographic facility, S191 spectroradiometer and S192 multispectral scanner, were compared with surface observations. The anticyclonic edge of the Gulf Stream could be identified in the Skylab S190A and B photographs, but the cyclonic edge was obscured by clouds. The aircraft photographs were judged not useful for spectral analysis because vignetting caused the blue/green ratios to be dependent on the position in the photograph. The spectral measurement technique could not identify the anticyclonic front, but mass of Florida Bay water which was in the process of flowing into the Straits could be identified and classified. Monte Carlo simulations of the visible spectrum showed that the aerosol concentration could be estimated and a correction technique was devised.

  18. The effect of the low Earth orbit environment on space solar cells: Results of the advanced photovoltaic experiment (S0014)

    NASA Technical Reports Server (NTRS)

    Brinker, David J.; Hickey, John R.

    1992-01-01

    The Advanced Photovoltaic Experiment (APEX), containing over 150 solar cells and sensors, was designed to generate laboratory reference standards as well as to explore the durability of a wide variety of space solar cells. Located on the leading edge of the Long Duration Exposure Facility (LDEF), APEX received the maximum possible dosage of atomic oxygen and ultraviolet radiation, as well as enormous numbers of impacts from micrometeoroids and debris. The effect of the low earth orbital (LEO) environment on the solar cells and materials of APEX will be discussed in this paper. The on-orbit performance of the solar cells, as well as a comparison of pre- and postflight laboratory performance measurements, will be presented.

  19. Hysteresis in voltage-gated channels.

    PubMed

    Villalba-Galea, Carlos A

    2016-09-30

    Ion channels constitute a superfamily of membrane proteins found in all living creatures. Their activity allows fast translocation of ions across the plasma membrane down the ion's transmembrane electrochemical gradient, resulting in a difference in electrical potential across the plasma membrane, known as the membrane potential. A group within this superfamily, namely voltage-gated channels, displays activity that is sensitive to the membrane potential. The activity of voltage-gated channels is controlled by the membrane potential, while the membrane potential is changed by these channels' activity. This interplay produces variations in the membrane potential that have evolved into electrical signals in many organisms. These signals are essential for numerous biological processes, including neuronal activity, insulin release, muscle contraction, fertilization and many others. In recent years, the activity of the voltage-gated channels has been observed not to follow a simple relationship with the membrane potential. Instead, it has been shown that the activity of voltage-gated channel displays hysteresis. In fact, a growing number of evidence have demonstrated that the voltage dependence of channel activity is dynamically modulated by activity itself. In spite of the great impact that this property can have on electrical signaling, hysteresis in voltage-gated channels is often overlooked. Addressing this issue, this review provides examples of voltage-gated ion channels displaying hysteretic behavior. Further, this review will discuss how Dynamic Voltage Dependence in voltage-gated channels can have a physiological role in electrical signaling. Furthermore, this review will elaborate on the current thoughts on the mechanism underlying hysteresis in voltage-gated channels.

  20. Preisach modeling of piezoceramic and shape memory alloy hysteresis

    NASA Astrophysics Data System (ADS)

    Hughes, Declan C.; Wen, John T.

    1996-05-01

    Smart materials such as piezoceramics, magnetostrictive materials, and shape memory alloys exhibit significant hysteresis, especially when driven with large input signals. Hysteresis can lead to unwanted harmonics, inaccuracy in open loop control, and instability in closed loop control. The Preisach independent domain hysteresis model has been shown to capture the major features of hysteresis arising in ferromagnetic materials. Noting the similarity between the microscopic domain kinematics that generate static hysteresis effects in ferromagnetics, piezoceramics, and shape memory alloys, we apply the Preisach model for the hysteresis in piezoceramic and shape memory alloy materials. This paper reviews the basic properties of the Preisach model, discusses control-theoretic issues such as identification, simulation, and inversion, and presents experimental results for piezoceramic sheet actuators bonded to a flexible aluminum beam, and a Nitinol SMA wire muscle that applies a bending force to the end of a beam.

  1. Preisach modeling of piezoceramic and shape memory alloy hysteresis

    NASA Astrophysics Data System (ADS)

    Hughes, Declan; Wen, John T.

    1997-06-01

    Smart materials such as piezoceramics, magnetostrictive materials, and shape memory alloys exhibit hysteresis, and the larger the input signal the larger the effect. Hysteresis can lead to unwanted harmonics, inaccuracy in open loop control, and instability in closed loop control. The Preisach independent domain hysteresis model has been shown to capture the major features of hysteresis arising in ferromagnetic materials. Noting the similarity between the microscopic domain kinematics that generate static hysteresis effects in ferromagnetics, piezoceramics, and shape memory alloys (SMAs), we apply the Preisach model for the hysteresis in piezoceramic and shape memory alloy materials. This paper reviews the basic properties of the Preisach model, discusses control-theoretic issues such as identification, simulation, and inversion, and presents experimental results for piezoceramic sheet actuators bonded to a flexible aluminum beam, and a Nitinol SMA wire muscle that applies a bending force to the end of a beam.

  2. Improving Science Literacy and Earth Science Awareness Through an Intensive Summer Research Experience in Paleobiology

    NASA Astrophysics Data System (ADS)

    Heim, N. A.; Saltzman, J.; Payne, J.

    2014-12-01

    The chasm between classroom science and scientific research is bridged in the History of Life Internships at Stanford University. The primary foci of the internships are collection of new scientific data and original scientific research. While traditional high school science courses focus on learning content and laboratory skills, students are rarely engaged in real scientific research. Even in experiential learning environments, students investigate phenomena with known outcomes under idealized conditions. In the History of Life Internships, high school youth worked full time during the summers of 2013 and 2014 to collect body size data on fossil Echinoderms and Ostracods, measuring more than 20,000 species in total. These data are contributed to the larger research efforts in the Stanford Paleobiology Lab, but they also serve as a source of data for interns to conduct their own scientific research. Over the course of eight weeks, interns learn about previous research on body size evolution, collect data, develop their own hypotheses, test their hypotheses, and communicate their results to their peers and the larger scientific community: the 2014 interns have submitted eight abstracts to this meeting for the youth session entitled Bright STaRS where they will present their research findings. Based on a post-internship survey, students in the 2013 History of Life cohort had more positive attitudes towards science and had a better understanding of how to conduct scientific research compared to interns in the Earth Sciences General Internship Program, where interns typically do not complete their own research project from start to finish. In 2014, we implemented both pre- and post-internship surveys to determine if these positive attitudes were developed over the course of the internship. Conducting novel research inspires both the students and instructors. Scientific data collection often involves many hours of repetitive work, but answering big questions typically

  3. Hysteresis prediction inside magnetic shields and application.

    PubMed

    Morić, Igor; De Graeve, Charles-Marie; Grosjean, Olivier; Laurent, Philippe

    2014-07-01

    We have developed a simple model that is able to describe and predict hysteresis behavior inside Mumetal magnetic shields, when the shields are submitted to ultra-low frequency (<0.01 Hz) magnetic perturbations with amplitudes lower than 60 μT. This predictive model has been implemented in a software to perform an active compensation system. With this compensation the attenuation of longitudinal magnetic fields is increased by two orders of magnitude. The system is now integrated in the cold atom space clock called PHARAO. The clock will fly onboard the International Space Station in the frame of the ACES space mission.

  4. Fingerprint image enhancement by differential hysteresis processing.

    PubMed

    Blotta, Eduardo; Moler, Emilce

    2004-05-10

    A new method to enhance defective fingerprints images through image digital processing tools is presented in this work. When the fingerprints have been taken without any care, blurred and in some cases mostly illegible, as in the case presented here, their classification and comparison becomes nearly impossible. A combination of spatial domain filters, including a technique called differential hysteresis processing (DHP), is applied to improve these kind of images. This set of filtering methods proved to be satisfactory in a wide range of cases by uncovering hidden details that helped to identify persons. Dactyloscopy experts from Policia Federal Argentina and the EAAF have validated these results.

  5. Mechano-electric optoisolator transducer with hysteresis

    NASA Astrophysics Data System (ADS)

    Ciuruş, I. M.; Dimian, M.; Graur, A.

    2011-01-01

    This article presents a theoretical and experimental study of designing a mechano-electric optoisolator transducer with hysteresis. Our research is centred upon designing transducers on the basis of optical sensors, as photoelectric conversions eliminate the influence of electromagnetic disturbances. Conversion of the rotation/translation motions into electric signals is performed with the help of a LED-photoresistor Polaroid optocoupler. The driver of the optocoupler's transmitter module is an independent current source. The signal conditioning circuit is a Schmitt trigger circuit. The device is designed to be applied in the field of automation and mechatronics.

  6. Hysteresis prediction inside magnetic shields and application

    SciTech Connect

    Morić, Igor; De Graeve, Charles-Marie; Grosjean, Olivier; Laurent, Philippe

    2014-07-15

    We have developed a simple model that is able to describe and predict hysteresis behavior inside Mumetal magnetic shields, when the shields are submitted to ultra-low frequency (<0.01 Hz) magnetic perturbations with amplitudes lower than 60 μT. This predictive model has been implemented in a software to perform an active compensation system. With this compensation the attenuation of longitudinal magnetic fields is increased by two orders of magnitude. The system is now integrated in the cold atom space clock called PHARAO. The clock will fly onboard the International Space Station in the frame of the ACES space mission.

  7. Importance of Considering Hysteresis in Macroscopic Models of Two-phase Flow in Porous Media

    NASA Astrophysics Data System (ADS)

    Cihan, A.; Birkholzer, J. T.; Trevisan, L.; Gonzalez-Nicolas Alvarez, A.; Illangasekare, T. H.

    2016-12-01

    Considering hysteresis in the traditional Darcy equation-based models is necessary to accurately capture the two phase flow behavior when subsurface systems experience successive drainage and imbibition processes such as in the case of geological carbon storage (GCS). Numerical simulators solving two-phase flow equations must make reliable predictions of fluid distributions during injection and post-injection redistribution of CO2, which is essential for developing appropriate monitoring and assessment plans in order to minimize risks of leakage (e.g., through fractures and/or abandoned wells). Generally, existing numerical simulators of the two-phase flow either neglect the hysteresis or include hysteresis based on the empirical constitutive relationships, not suitably incorporating basic physics of capillary flow with entrapment. This study presents testing of new mathematical hysteretic capillary pressure - saturation - relative permeability models with the goal of more accurately predicting the post-injection distribution of the fluids. The developed macroscopic constitutive models are based on basic physics of two-phase capillary displacements at pore-scale and void volume fraction distribution and connectivity properties. To test the new models, a traditional two-phase flow model with the developed hysteretic functions as input is compared against some intermediate-scale flow cell experiments conducted under macroscopically homogeneous and heterogeneous conditions. The model testing results that will be presented demonstrate the importance of taking into account hysteresis in the constitutive models of the traditional two-phase flow models for more accurate prediction of post-injection plume distribution.

  8. Diapirism on Venus and the Early Earth and The thermal effect of fluid flows in AECL's Tunnel Sealing Experiment

    NASA Astrophysics Data System (ADS)

    Robin, Catherine M. I.

    2010-12-01

    Flow instabilities occur at all scales in planetary systems. In this thesis we examine three cases of such instabilities, on three very different length scales. In the first part, we test the idea that Archean granite-greenstone belts (GGBs) form by crustal diapirism, or Rayleigh-Taylor instabilities. GGBs are characterized by large granitic domes (50-100 km in diameter) embedded in narrow keel-shaped greenstones. They are ubiquitous in Archean (> 2.5 Ga) terrains, but rare thereafter. We performed finite element calculations for a visco-elastic, temperature-dependent, non-Newtonian crust under conditions appropriate for the Archean, which show that dense low-viscosity volcanics overlying a felsic basement will overturn diapirically in as little as 10 Ma, displacing as much as 60 % of the volcanics to the lower crust. This surprisingly fast overturn rate suggests that diapiric overturn dominated crustal tectonics in the hot conditions of the Early Earth, becoming less important as the Earth cooled. Moreover, the deposition of large volumes of wet basaltic volcanics to the lower crust may provide the source for the formation of the distinctly Archean granitic rocks which dominate Earth's oldest continents. The second part examines the origin of Venusian coronae, circular volcanic features unique to Venus. Coronae are thought to result from small instabilities (diapirs) from the core-mantle boundary, which are typical of stagnant-lid convection. However, most young coronae are located in a region surrounded by long-lived hotspots, typical of a more active style of mantle convection. Using analogue experiments in corn syrup heated from below, we show that the co-existence of diapirs and long-lived mantle plumes are a direct consequence of the catastrophic overturn of the cold Venusian lithosphere thought to have occurred ˜ 700 Ma ago. In the last part we analyze the thermal effect of fluid flow through a full-scale experiment testing clay and concrete tunnel seals in

  9. Launching and Undergraduate Earth System Science Curriculum with a Focus on Global Sustainability: the Loma Linda University Experience

    NASA Astrophysics Data System (ADS)

    Ford, R. E.; Dunbar, S. G.; Soret, S.; Wiafe, S.; Gonzalez, D.; Rossi, T.

    2004-12-01

    The vision of the School of Science and Technology (SST) at Loma Linda University (LLU) is to develop an interdisciplinary approach to doing science that bridges the social, biological, earth, and health sciences. It will provide opportunities for undergraduate, graduate, and professional students to apply new tools and concepts to the promotion of global service and citizenship while addressing issues of global poverty, health and disease, environmental degradation, poverty, and social inequality. A primary teaching strategy will be to involve students with faculty in applied field social and science policy research on "global sustainability" issues and problems in real places such as Fiji, Jamaica, Honduras, Bahamas, East Africa, and the US southwest (Great Basin, Salton Sea, coastal California, southern Utah). Recently we became a partner in the NASA/USRA ESSE21 Project (Earth System Science Education for the 21st Century). We bring to that consortium strengths and experience in areas such as social policy, sustainable development, medicine, environmental health, disaster mitigation, humanitarian relief, geoinformatics and bioinformatics. This can benefit ESSE21, the NASA Earth Enterprise Mission, and the wider geosciences education community by demonstrating the relevance of such tools, and methods outside the geosciences. Many of the graduate and undergraduate students who will participate in the new program come from around the world while many others represent underserved populations in the United States. The PI and Co-PIs have strong global as well as domestic experience serving underrepresented communities, e.g. Seth Wiafe from Ghana, Sam Soret from Spain, Stephen Dunbar from the South Pacific, and Robert Ford from Latin America and Africa. Our partnership in implementation will include other institutions such as: La Sierra University, the California State University, Pomona, Center for Geographic Information Science Research, ESRI, Inc., the University of

  10. THE EFFECT OF LIQUID STRUCTURE ON CONTACT ANGLE HYSTERESIS

    DTIC Science & Technology

    Contact angle hysteresis was measured for a variety of liquids on condensed monolayers of 17-(perfluoroheptyl)-heptadecanoic acid adsorbed on...into the porous monolayer. However, contact angle hysteresis was negligible when the average diameter of the liquid molecules was larger than the...monolayers by contact angle hysteresis measurements on a series of liquids having gradations in molecular volume. The results of this investigation

  11. Method and apparatus for sub-hysteresis discrimination

    DOEpatents

    De Geronimo, Gianluigi

    2015-12-29

    Embodiments of comparator circuits are disclosed. A comparator circuit may include a differential input circuit, an output circuit, a positive feedback circuit operably coupled between the differential input circuit and the output circuit, and a hysteresis control circuit operably coupled with the positive feedback circuit. The hysteresis control circuit includes a switching device and a transistor. The comparator circuit provides sub-hysteresis discrimination and high speed discrimination.

  12. Contact angle hysteresis on randomly rough surfaces: a computational study.

    PubMed

    David, Robert; Neumann, A Wilhelm

    2013-04-09

    Wetting is important in many applications, and the solid surfaces being wet invariably feature some amount of surface roughness. A free energy-based computational simulation is used to study the effect of roughness on wetting and especially contact angle hysteresis. On randomly rough, self-affine surfaces, it is found that hysteresis depends primarily on the value of the Wenzel roughness parameter r, increasing in proportion with r - 1. Micrometer-level roughness causes hysteresis of a few degrees.

  13. On the rationale for hysteresis in economic decisions

    NASA Astrophysics Data System (ADS)

    Rios, Luis A.; Rachinskii, Dmitrii; Cross, Rod

    2017-02-01

    In the social sciences there are plausible reasons to postulate that hysteresis effects are important. The available evidence, however, is predominantly at the macro level. In this paper we review the evidence regarding hysteresis in the neural processes underlying human behavior. We argue that there is a need for experimental and neuroimaging studies to fill the gap in knowledge about hysteresis processes at the micro level in the social sciences.

  14. Preliminary Experiments for the Assessment of VW-Band Links for Space-Earth Communications

    NASA Technical Reports Server (NTRS)

    Nessel, James A.; Acosta, Roberto J.; Miranda, Felix A.

    2013-01-01

    Since September 2012, NASA Glenn Research Center has deployed a microwave profiling radiometer at White Sands, NM, to estimate atmospheric propagation effects on communications links in the V and W bands (71-86GHz). Estimates of attenuation statistics in the millimeter wave due to gaseous and cloud components of the atmosphere show good agreement with current ITU-R models, but fail to predict link performance in the presence of moderate to heavy rain rates, due to the inherent limitations of passive radiometry. Herein, we discuss the preliminary results of these measurements and describe a design for a terrestrial link experiment to validaterefine existing rain attenuation models in the VW-bands.

  15. Earth Science Project Office (ESPO) Field Experiences During ORACLES, ATom, KORUS and POSIDON

    NASA Technical Reports Server (NTRS)

    Salazar, Vidal; Zavaleta, Jhony

    2017-01-01

    Very often, scientific field campaigns entail years of planning and incur substantial cost, especially if they involve the operation of large research aircraft in remote locations. Deploying and operating these aircrafts even for short periods of time poses challenges that, if not addressed properly, can have significant negative consequences and potentially jeopardize the success of a scientific campaign. Challenges vary from country to country and range from safety, health, and security risks to differences in cultural and social norms. Our presentation will focus on sharing experiences on the ESPO 2016 conducted field campaigns ORACLES, ATom, KORUS and POSIDON. We will focus on the best practices, lessons learned, international relations and coordination aspects of the country-specific experiences. This presentation will be part of the ICARE Conference (2nd International Conference on Airborne Research for the Environment (ICARE 2017) that will focus on "Developing the infrastructure to meet future scientific challenges". This unique conference and gathering of facility support experts will not only allow for dissemination and sharing of knowledge but also promote collaboration and networking among groups that support scientific research using airborne platforms around the globe.

  16. Dynamic hysteresis modeling including skin effect using diffusion equation model

    NASA Astrophysics Data System (ADS)

    Hamada, Souad; Louai, Fatima Zohra; Nait-Said, Nasreddine; Benabou, Abdelkader

    2016-07-01

    An improved dynamic hysteresis model is proposed for the prediction of hysteresis loop of electrical steel up to mean frequencies, taking into account the skin effect. In previous works, the analytical solution of the diffusion equation for low frequency (DELF) was coupled with the inverse static Jiles-Atherton (JA) model in order to represent the hysteresis behavior for a lamination. In the present paper, this approach is improved to ensure the reproducibility of measured hysteresis loops at mean frequency. The results of simulation are compared with the experimental ones. The selected results for frequencies 50 Hz, 100 Hz, 200 Hz and 400 Hz are presented and discussed.

  17. On the hysteresis behaviors of the higher spin Ising model

    NASA Astrophysics Data System (ADS)

    Akıncı, Ümit

    2017-10-01

    Hysteresis characteristics of the general Spin-S (S > 1) Blume-Capel model have been studied within the effective field approximation. Particular emphasis has been paid on the large negative valued crystal field region and it has been demonstrated for this region that, Spin-S Blume-Capel model has 2 S windowed hysteresis loop in low temperatures. Some interesting results have been obtained such as nested characteristics of the hysteresis loops of successive spin-S Blume-Capel model. Effect of the rising crystal field and temperature on these hysteresis behaviors have been investigated in detail and physical mechanisms have been given.

  18. Hysteresis phenomena of the intelligent driver model for traffic flow.

    PubMed

    Dahui, Wang; Ziqiang, Wei; Ying, Fan

    2007-07-01

    We present hysteresis phenomena of the intelligent driver model for traffic flow in a circular one-lane roadway. We show that the microscopic structure of traffic flow is dependent on its initial state by plotting the fraction of congested vehicles over the density, which shows a typical hysteresis loop, and by investigating the trajectories of vehicles on the velocity-over-headway plane. We find that the trajectories of vehicles on the velocity-over-headway plane, which usually show a hysteresis loop, include multiple loops. We also point out the relations between these hysteresis loops and the congested jams or high-density clusters in traffic flow.

  19. Causes and implications of colloid and microorganism retention hysteresis.

    PubMed

    Bradford, Scott A; Kim, Hyunjung

    2012-09-01

    Experiments were designed to better understand the causes and implications of colloid and microorganism retention hysteresis with transients in solution ionic strength (IS). Saturated packed column experiments were conducted using two sizes of carboxyl modified latex (CML) microspheres (0.1 and 1.1 μm) and microorganisms (coliphage φX174 and E. coli D21g) under various transient solution chemistry conditions, and 360 μm Ottawa sand that was subject to different levels of cleaning, namely, a salt cleaning procedure that removed clay particles, and a salt+acid cleaning procedure that removed clay and reduced microscopic heterogeneities due to metal oxides and surface roughness. Comparison of results from the salt and salt+acid treated sand indicated that microscopic heterogeneity was a major contributor to colloid retention hysteresis. The influence of this heterogeneity increased with IS and decreasing colloid/microbe size on salt treated sand. These trends were not consistent with calculated mean interaction energies (the secondary minima), but could be explained by the size of the electrostatic zone of influence (ZOI) near microscopic heterogeneities. In particular, the depth of local minima in the interaction energy has been predicted to increase with a decrease in the ZOI when the colloid size and/or the Debye length decreased (IS increased). The adhesive interaction was therefore largely irreversible for smaller sized 0.1 μm CML colloids, whereas it was reversible for larger 1.1 μm CML colloids. Similarly, the larger E. coli D21g exhibited greater reversibility in retention than φX174. However, direct comparison of CML colloids and microbes was not possible due to differences in size, shape, and surface properties. Retention and release behavior of CML colloids on salt+acid treated sand was much more consistent with mean interaction energies due to reduction in microscopic heterogeneities.

  20. Causes and implications of colloid and microorganism retention hysteresis

    NASA Astrophysics Data System (ADS)

    Bradford, Scott A.; Kim, Hyunjung

    2012-09-01

    Experiments were designed to better understand the causes and implications of colloid and microorganism retention hysteresis with transients in solution ionic strength (IS). Saturated packed column experiments were conducted using two sizes of carboxyl modified latex (CML) microspheres (0.1 and 1.1 μm) and microorganisms (coliphage φX174 and E. coli D21g) under various transient solution chemistry conditions, and 360 μm Ottawa sand that was subject to different levels of cleaning, namely, a salt cleaning procedure that removed clay particles, and a salt + acid cleaning procedure that removed clay and reduced microscopic heterogeneities due to metal oxides and surface roughness. Comparison of results from the salt and salt + acid treated sand indicated that microscopic heterogeneity was a major contributor to colloid retention hysteresis. The influence of this heterogeneity increased with IS and decreasing colloid/microbe size on salt treated sand. These trends were not consistent with calculated mean interaction energies (the secondary minima), but could be explained by the size of the electrostatic zone of influence (ZOI) near microscopic heterogeneities. In particular, the depth of local minima in the interaction energy has been predicted to increase with a decrease in the ZOI when the colloid size and/or the Debye length decreased (IS increased). The adhesive interaction was therefore largely irreversible for smaller sized 0.1 μm CML colloids, whereas it was reversible for larger 1.1 μm CML colloids. Similarly, the larger E. coli D21g exhibited greater reversibility in retention than φX174. However, direct comparison of CML colloids and microbes was not possible due to differences in size, shape, and surface properties. Retention and release behavior of CML colloids on salt + acid treated sand was much more consistent with mean interaction energies due to reduction in microscopic heterogeneities.

  1. Effects of RAM Exposure on a Low Earth Orbit BroadBand Radiometer (BBR): CERES Experience and Implications for EarthCARE

    NASA Technical Reports Server (NTRS)

    Matthews, Grant; Priestley, Kory; Thomas, Susan; Hess, Pil; Cooper, Denise; Walikainen, Dale

    2007-01-01

    In order to best detect real changes in the Earth's climate system it is estimated that space based instrumentation measuring the global Earth Radiation Budget (ERB) must remain calibrated with a stability of 0.3% per decade. This level of stability is beyond the specified accuracy of existing ERB programs such as the Clouds and the Earth's Radiant Energy System (CERES, using three broadband radiometric scanning channels: the shortwave (SW 0.3 - 5?m), total (0.3 - >100 micron), and window (8 - 12 micron)). When in low earth orbit, it has been shown that optical response to blue-UV radiance can be reduced significantly (> 3%) due to UV hardened contaminants deposited on the surface of the optics. Evidence suggests that exposure of telescope optics to the forward looking ram direction is the primary cause of this contamination build up. With typical onboard calibration lamps emitting very low energy in the blue-UV region, this darkening is not directly measurable using standard internal calibration techniques. This paper describes a study using a model of ram exposure induced contaminant deposition and darkening, in conjunction standard established in-flight vicarious and internal calibration techniques to derive the spectral shape of the darkening to which a broadband instrument is subjected. The results of the model when applied to the CERES instruments are shown. These findings are of great importance to the EarthCARE project, whose BBR uses one broadband telescope permanently looking forward at 45 degrees, with continual exposure to the ram direction. Specific attention may therefore be needed in the design of BBR optics and on-board calibration in order to prevent or compensate for the spectral darkening seen in the CERES project.

  2. EMSCOPE - Electromagnetic Component of EarthScope Backbone and Transportable Array Experiments 2006-2008

    NASA Astrophysics Data System (ADS)

    Egbert, G.; Evans, R.; Ingate, S.; Livelybrooks, D.; Mickus, K.; Park, S.; Schultz, A.; Unsworth, M.; Wannamaker, P.

    2007-12-01

    USArray (http://www.iris.edu/USArray) in conjunction with EMSOC (Electromagnetic Studies of the Continents) (http://emsoc.ucr.edu/emsoc) is installing magnetotelluric (MT) stations as part of Earthscope. The MT component of Earthscope consists of permanent (Backbone) and transportable long period stations to record naturally occurring, time varying electric and magnetic fields to produce a regional lithospheric/asthensospheric electrical conductivity map of the United States. The recent arrival of 28 long period MT instruments allows for the final installation of the Backbone stations throughout the US and yearly transportable array studies. The Backbone MT survey consists of 7 stations spaced throughout the continental US with preliminary installation at Soap Creek, Oregon; Parkfield, California; Braden, Missouri and Socorro, New Mexico.Siting and permitting are underway or completed at stations in eastern Montana, northern Wisconsin and Virginia. These stations will be recording for at least five years to determine electrical conductivities at depths that extend into the mantle transition zone. The first transportable array experiment was performed in the summer and fall of 2006 in central and eastern Oregon (Oregon Pilot Project) using equipment loaned from EMSOC. Thirty-one long period MT stations were recorded with 14 to 21 day occupations. Preliminary 3D inverse models indicate several lithospheric electrical conductivity anomalies including a linear zone marked by low-high conductivity transition along the Klamath-Blue Mountain Lineament associated with a linear trend of gravity minima. High electrical conductivity values occur in the upper crust under the accreted terrains in the Blue Mountains region. The second transportable array experiment was performed in the summer and fall of 2007 and completes coverage of the Oregon, Washington, and western Idaho, targeting the Cascadia subduction zone, Precambrian boundaries, and sub-basalt lithologies. The 2008

  3. A generalized Prandtl-Ishlinskii model for characterizing the rate-independent and rate-dependent hysteresis of piezoelectric actuators.

    PubMed

    Gan, Jinqiang; Zhang, Xianmin; Wu, Heng

    2016-03-01

    In this paper, a generalized hysteresis model is developed to describe both rate-independent and rate-dependent hysteresis in piezoelectric actuators. Based on the classical Prandtl-Ishlinskii (P-I) model, the developed model adds a quadratic polynomial and makes other small changes. When it is used to describe rate-independent hysteresis, the parameters of the model are constants, which can be identified by self-adaptive particle swarm optimization. The effectiveness of this rate-independent modified P-I model is demonstrated by comparing simulation results of the developed model and the classic Prandtl-Ishlinskii model. Simulation results suggest that the rate-independent modified P-I model can describe hysteresis more precisely. Compared with the classical P-I model, the rate-independent modified P-I model reduces modeling error by more than 50%. When it is used to describe rate-independent hysteresis, a one-side operator is adopted and the parameters are functions with input frequency. The results of the experiments and simulations have shown that the proposed models can accurately describe both rate-independent and rate-dependent hysteresis in piezoelectric actuators.

  4. Impact into the earth's ocean floor - Preliminary experiments, a planetary model, and possibilities for detection

    NASA Technical Reports Server (NTRS)

    Mckinnon, W. B.

    1982-01-01

    Impact processes and plate tectonics are invoked in an experimental study of craters larger than 100 km in diameter on the ocean floor. Although the results obtained from 22-caliber (383 m/sec) ammunition experiments using dense, saturated sand as a target medium cannot be directly scaled to large events, the phenomenology exhibited is that expected of actual craters on the ocean floor: steep, mixed ejecta plume, gravitational adjustment of the crater to form a shallow basin, and extensive reworking of the ejecta, rim, and floor materials by violent collapse of the transient water cavity. Excavation into the mantle is predicted, although asthenospheric influence on outer ring formation is not. The clearest geophysical signature of such a crater is not topography; detection should instead be based on gravity and geoid anomalies due to uplift of the Moho, magnetic anomalies, and seismic resolution of the Moho uplift and crater formation fault planes.

  5. Broadband Ocean Bottom Instruments Record Earth's Free Oscillations during the Hawaiian PLUME Experiment

    NASA Astrophysics Data System (ADS)

    Laske, G.; Orcutt, J. A.; Collins, J. A.; Detrick, R. S.; Wolfe, C. J.; Solomon, S. C.; Bercovici, D. A.; Hauri, E. H.

    2007-12-01

    Ocean islands are usually thought of as being noisy sites for the global seismic network (GSN). For example, in the microseism band between 15 and 5~s, noise levels can easily be 10-20~dB higher than at stations in the interiors of continents. On the other hand, and somewhat curiously, several Pacific island sites are some of the quietest to record vertical ground movement in the free oscillation band beyond 200~s. This includes station KIP (Kipapa, on Oahu/Hawaii) that is operated jointly by the USGS and the French GEOSCOPE group. During the Hawaiian PLUME (Plume-Lithosphere Undersea Melt Experiment) deployment, we collected continuous seismic data from January 2005 through June 2007, using a variety of seismic sensors deployed on land and on the ocean floor. Ten broadband land stations were equipped with Wielandt--Streckeisen STS--2 seismometers, and about 70 ocean bottom sites were occupied with Güralp CMG-3T, Nanometrics Trillium 40 or Trillium 240 seismometers, and a Cox--Webb differential pressure gauge (DPG). This experiment gives us the unique opportunity to assess the quality and variability of ultra--long period seismic signals, for specific sensors, and evaluate the benefit and limits of deploying broad--band sensors on the ocean floor. In 2005, we recorded five very large earthquakes with scalar seismic moments of M0=2x1020~Nm or larger. One of these was the MS=8.2 28 March aftershock of the great 26 December 2004 Sumatra--Andaman earthquake. At station KIP, which is equipped with a very broad--band STS--1, the free oscillation spectrum is of extremely high quality. We can identify mode 0S2 (~0.31~mHz) that is observed only for the largest earthquakes, and only at the quietest GSN stations. Even on the STS--2 record, mode 0S3 (~0.47~mHz) is clearly discernible. The quality of spectra recorded on the OBSs varies greatly, but at some sites we observe mode 0S6 (~1.04~mHz). These records are greatly superior to those at GSN stations POHA (island of Hawaii

  6. Preliminary Experiments for the Assessment of V/W-band Links for Space-Earth Communications

    NASA Technical Reports Server (NTRS)

    Nessel, James A.; Acosta, Roberto J.; Miranda, Felix A.

    2013-01-01

    Since September 2012, NASA Glenn Research Center has deployed a microwave profiling radiometer at White Sands, NM, to estimate atmospheric propagation effects on communications links in the V and W bands (71-86GHz). Estimates of attenuation statistics in the millimeter wave due to gaseous and cloud components of the atmosphere show good agreement with current ITU-R models, but fail to predict link performance in the presence of moderate to heavy rain rates, due to the inherent limitations of passive radiometry. Herein, we discuss the preliminary results of these measurements and describe a design for a terrestrial link experiment to validate/refine existing rain attenuation models in the V/Wbands.

  7. Ultraviolet spectroscopy of meteoric debris: In situ calibration experiments from Earth orbit

    NASA Technical Reports Server (NTRS)

    Nuth, J. A., III; Wdowiak, T. J.; Kubinec, W. R.

    1986-01-01

    It is proposed to carry out slitless spectroscopy at ultraviolet wavelengths from orbit of meteoric debris associated with comets. The Eta Aquarid, Orionid/Halley, and the Persied/1962 862 Swift-Tuttle showers would be principal targets. Low light level, ultraviolet video technique will be used during night side of the orbit in a wide field, earthward viewing mode. Data will be stored in compact video cassette recorders. The experiment may be configured as a GAS package or in the HITCHHIKER mode. The latter would allow flexible pointing capability beyond that offered by shuttle orientation of the GAS package, and doubling of the data record. The 1100 to 3200 A spectral region should show emissions of atomic, ionic, and molecular species of interest on cometary and solar system studies.

  8. Ultraviolet spectroscopy of meteoric debris: In situ calibration experiments from earth orbit

    NASA Technical Reports Server (NTRS)

    Nuth, Joseph A.; Wdowiak, Thomas J.; Kubinec, William R.

    1987-01-01

    It is proposed to carry out slitless spectroscopy at ultraviolet wavelengths from orbit of meteoric debris associated with comets. The Eta Aquarid, Orionid/Halley, and the Persied/1962 862 Swift-Tuttle showers would be principal targets. Low light level, ultraviolet video technique will be used during the night side of the orbit in a wide field, earthward viewing mode. Data will be stored in compact video cassette recorders. The experiment may be configured as a GAS package or in the HITCHHIKER mode. The latter would allow flexible pointing capability beyond that offered by shuttle orientation of the GAS package, and doubling of the data record. The 1100 to 3200 A spectral region should show emissions of atomic, ionic, and molecular species of interest on cometary and solar system studies.

  9. An Experiment to Study Sporadic Sodium Layers in the Earth's Mesosphere and Lower Thermosphere

    NASA Technical Reports Server (NTRS)

    Swenson, Charles M.

    2002-01-01

    The Utah State University / Space Dynamics Lab was funded under a NASA Grant. This investigation has been part of Rockwell Universities Sudden Atom Layer Investigation (SAL). USU/SDL provided an electron density measurement instrument, the plasma frequency probe, which was launched on the vehicle 21.117 from Puerto-Rico in February of 1998. The instrument successfully measured electron density as designed and measurement techniques included in this version of the Plasma Frequency probe provided valuable insight into the electron density structures associated with sudden sodium layers in a collisional plasma. Electron density data was furnished to Rockwell University but no science meetings were held by Rockwell Data from the instrument was presented to the scientific community at the URSI General Session in 1999. A paper is in preparation for publication in Geophysical Research Letters. The following document provides a summary of the experiment and data obtained as a final report on this grant.

  10. High-energy cosmic-ray fluxes in the Earth atmosphere: Calculations vs experiments

    NASA Astrophysics Data System (ADS)

    Kochanov, A. A.; Sinegovskaya, T. S.; Sinegovsky, S. I.

    2008-12-01

    A new calculation of the atmospheric fluxes of cosmic-ray hadrons and muons in the energy range 10-105 GeV has been performed for the set of hadron production models, EPOS 1.6, QGSJET II-03, SIBYLL 2.1, and others that are of interest to cosmic-ray physicists. The fluxes of secondary cosmic rays at several levels in the atmosphere are computed using directly data of the ATIC-2, GAMMA experiments, and the model proposed recently by Zatsepin and Sokolskaya as well as the parameterization of the primary cosmic-ray spectrum by Gaisser and Honda. The calculated energy spectra of the hadrons and muon flux as a function of zenith angle are compared with measurements as well as other calculations. The effect of uncertainties both in the primary cosmic-ray flux and hadronic model predictions on the spectra of atmospheric hadrons and muons is considered.

  11. Hysteresis compensation of the piezoelectric ceramic actuators-based tip/tilt mirror with a neural network method in adaptive optics

    NASA Astrophysics Data System (ADS)

    Wang, Chongchong; Wang, Yukun; Hu, Lifa; Wang, Shaoxin; Cao, Zhaoliang; Mu, Quanquan; Li, Dayu; Yang, Chengliang; Xuan, Li

    2016-05-01

    The intrinsic hysteresis nonlinearity of the piezo-actuators can severely degrade the positioning accuracy of a tip-tilt mirror (TTM) in an adaptive optics system. This paper focuses on compensating this hysteresis nonlinearity by feed-forward linearization with an inverse hysteresis model. This inverse hysteresis model is based on the classical Presiach model, and the neural network (NN) is used to describe the hysteresis loop. In order to apply it in the real-time adaptive correction, an analytical nonlinear function derived from the NN is introduced to compute the inverse hysteresis model output instead of the time-consuming NN simulation process. Experimental results show that the proposed method effectively linearized the TTM behavior with the static hysteresis nonlinearity of TTM reducing from 15.6% to 1.4%. In addition, the tip-tilt tracking experiments using the integrator with and without hysteresis compensation are conducted. The wavefront tip-tilt aberration rejection ability of the TTM control system is significantly improved with the -3 dB error rejection bandwidth increasing from 46 to 62 Hz.

  12. Residual stresses and vector hysteresis modeling

    NASA Astrophysics Data System (ADS)

    Ktena, Aphrodite

    2016-04-01

    Residual stresses in magnetic materials, whether the result of processing or intentional loading, leave their footprint on macroscopic data, such hysteresis loops and differential permeability measurements. A Preisach-type vector model is used to reproduce the phenomenology observed based on assumptions deduced from the data: internal stresses lead to smaller and misaligned grains, hence increased domain wall pinning and angular dispersion of local easy axes, favouring rotation as a magnetization reversal mechanism; misaligned grains contribute to magnetostatic fields opposing the direction of the applied field. The model is using a vector operator which accounts for both reversible and irreversible processes; the Preisach concept for interactions for the role of stress related demagnetizing fields; and a characteristic probability density function which is constructed as a weighed sum of constituent functions: the material is modeled as consisting of various subsystems, e.g. reversal mechanisms or areas subject to strong/weak long range interactions and each subsystem is represented by a constituent probability density function. Our assumptions are validated since the model reproduces the hysteresis loops and differential permeability curves observed experimentally and calculations involving rotating inputs at various residual stress levels are consistent and in agreement with experimental evidence.

  13. Modeling Anomalous Hysteresis in Perovskite Solar Cells.

    PubMed

    van Reenen, Stephan; Kemerink, Martijn; Snaith, Henry J

    2015-10-01

    Organic-inorganic lead halide perovskites are distinct from most other semiconductors because they exhibit characteristics of both electronic and ionic motion. Accurate understanding of the optoelectronic impact of such properties is important to fully optimize devices and be aware of any limitations of perovskite solar cells and broader optoelectronic devices. Here we use a numerical drift-diffusion model to describe device operation of perovskite solar cells. To achieve hysteresis in the modeled current-voltage characteristics, we must include both ion migration and electronic charge traps, serving as recombination centers. Trapped electronic charges recombine with oppositely charged free electronic carriers, of which the density depends on the bias-dependent ion distribution in the perovskite. Our results therefore show that reduction of either the density of mobile ionic species or carrier trapping at the perovskite interface will remove the adverse hysteresis in perovskite solar cells. This gives a clear target for ongoing research effort and unifies previously conflicting experimental observations and theories.

  14. HYSTERESIS BETWEEN DISTINCT MODES OF TURBULENT DYNAMOS

    SciTech Connect

    Karak, Bidya Binay; Brandenburg, Axel; Kitchatinov, Leonid L.

    2015-04-20

    Nonlinear mean-field models of the solar dynamo show long-term variability, which may be relevant to different states of activity inferred from long-term radiocarbon data. This paper is aimed at probing the dynamo hysteresis predicted by the recent mean-field models of Kitchatinov and Olemskoy with direct numerical simulations. We perform three-dimensional (3D) simulations of large-scale dynamos in a shearing box with helically forced turbulence. As an initial condition, we either take a weak random magnetic field or we start from a snapshot of an earlier simulation. Two quasi-stable states are found to coexist in a certain range of parameters close to the onset of the large-scale dynamo. The simulations converge to one of these states depending on the initial conditions. When either the fractional helicity or the magnetic Prandtl number is increased between successive runs above the critical value for onset of the dynamo, the field strength jumps to a finite value. However, when the fractional helicity or the magnetic Prandtl number is then decreased again, the field strength stays at a similar value (strong field branch) even below the original onset. We also observe intermittent decaying phases away from the strong field branch close to the point where large-scale dynamo action is just possible. The dynamo hysteresis seen previously in mean-field models is thus reproduced by 3D simulations. Its possible relation to distinct modes of solar activity such as grand minima is discussed.

  15. Percolation and hysteresis in macroscopic capillarity

    NASA Astrophysics Data System (ADS)

    Hilfer, Rudolf

    2010-05-01

    The concepts of relative permeability and capillary pressure are crucial for the accepted traditional theory of two phase flow in porous media. Recently a theoretical approach was introduced that does not require these concepts as input [1][2][3]. Instead it was based on the concept of hydraulic percolation of fluid phases. The presentation will describe this novel approach. It allows to simulate processes with simultaneous occurence of drainage and imbibition. Furthermore, it predicts residual saturations and their spatiotemporal changes during two phase immiscible displacement [1][2][3][4][5]. [1] R. Hilfer. Capillary Pressure, Hysteresis and Residual Saturation in Porous Media, Physica A, vol. 359, pp. 119, 2006. [2] R. Hilfer. Macroscopic Capillarity and Hysteresis for Flow in Porous Media, Physical Review E, vol. 73, pp. 016307, 2006. [3] R. Hilfer. Macroscopic capillarity without a constitutive capillary pressure function, Physica A, vol. 371, pp. 209, 2006. [4] R. Hilfer. Modeling and Simulation of Macrocapillarity, in: P. Garrido et al. (eds.) Modeling and Simulation of Materials vol. CP1091, pp. 141, American Institute of Physcis, New York, 2009. [5] R. Hilfer and F. Doster. Percolation as a basic concept for macroscopic capillarity, Transport in Porous Media, DOI 10.1007/s11242-009-9395-0, in print, 2009.

  16. Hysteresis and feedback of ice sheet response

    NASA Astrophysics Data System (ADS)

    Abe-Ouchi, A.; Saito, F.; Takahashi, K.

    2014-12-01

    Investigating the response of ice sheets to climatic forcings in the past by climate-ice sheet modelling is important for understanding the ice sheets' change. The 100-kyr cycle of the large Northern Hemisphere ice sheets and fast termination of the glacial cycle are the prominent pattern known from paleoclimate records. We simulate the past glacial cycles with an ice sheet model, IcIES in combination with a general circulation model, MIROC, using the time series of insolation and atmospheric CO2. Feedback processes between ice sheet and atmosphere such as the ice albedo feedback, the elevation-mass balance feedback, desertification effect and stationary wave feedback are analyzed. We show that the threshold of termination of the glacial cycles can be explained by the pattern of the hysteresis of ice sheet change, i.e. multiple steady states of the ice sheets under climatic forcings. We find that slope of the upper branch of the multiple equilibria curve for Laurentide ice volumes is fundamental for the observed glacial patterns. Finally, we discuss the similarity and difference between the hysteresis structure of ice sheets variation for Northern Hemisphere ice sheets, Antarctica and Greenland.

  17. Hysteresis in both sediment transport and water turbulence contribute to seismic hysteresis in a steep mountain stream

    NASA Astrophysics Data System (ADS)

    Roth, D. L.; Finnegan, N. J.; Brodsky, E. E.; Rickenmann, D.; Turowski, J. M.; Badoux, A.; Gimbert, F.

    2016-12-01

    Hysteresis in the relationship between bedload transport and river stage is a well-documented phenomenon with multiple known causes. Consequently, numerous studies have suggested that hysteresis observed in the relationship between seismic amplitudes recorded near rivers and some measure of flow strength (i.e., discharge or stage) is the signature of bedload transport. We use a metric (Ψ) for the normalized magnitude of hysteresis during individual transport events in the Erlenbach stream (local slope 10%) in the Swiss Prealps to compare hysteresis found in seismic data with hysteresis in in-bed geophone plate system recordings, a well-calibrated proxy for direct sediment transport measurements. We find that while both the geophones and seismometers demonstrate hysteresis, the magnitude and direction of hysteresis are not correlated between these data, indicating that an additional source of hysteresis must be present in the seismic signal. Seismic hysteresis also does not correlate with the magnitude of sediment transport recorded by the geophones, contrary to previous studies' assumptions. Our results indicate that hydrologic sources and changes in water turbulence due to evolving boundary conditions at the bed, rather than changes in sediment transport rates, may sometimes contribute to or even dominate the hysteresis observed in seismic amplitudes near rivers. This appears to be especially relevant in steep rivers where the flow depth is low or comparable to the largest roughness elements on the bed, or where highly turbulent features such as waterfalls or cascades may contribute significantly to the seismic signal. These effects must be better understood in order to determine the extent to which seismic hysteresis may relate to sediment transport rates in different fluvial settings and improve our ability to assess bedload transport and bed evolution through hysteresis in seismic signals near rivers.

  18. Contamination Examples and Lessons from Low Earth Orbit Experiments and Operational Hardware

    NASA Technical Reports Server (NTRS)

    Pippin, Gary; Finckenor, Miria M.

    2009-01-01

    Flight experiments flown on the Space Shuttle, the International Space Station, Mir, Skylab, and free flyers such as the Long Duration Exposure Facility, the European Retrievable Carrier, and the EFFU, provide multiple opportunities for the investigation of molecular contamination effects. Retrieved hardware from the Solar Maximum Mission satellite, Mir, and the Hubble Space Telescope has also provided the means gaining insight into contamination processes. Images from the above mentioned hardware show contamination effects due to materials processing, hardware storage, pre-flight cleaning, as well as on-orbit events such as outgassing, mechanical failure of hardware in close proximity, impacts from man-made debris, and changes due to natural environment factors.. Contamination effects include significant changes to thermal and electrical properties of thermal control surfaces, optics, and power systems. Data from several flights has been used to develop a rudimentary estimate of asymptotic values for absorptance changes due to long-term solar exposure (4000-6000 Equivalent Sun Hours) of silicone-based molecular contamination deposits of varying thickness. Recommendations and suggestions for processing changes and constraints based on the on-orbit observed results will be presented.

  19. Theory of plasma contactors in ground-based experiments and low Earth orbit

    NASA Technical Reports Server (NTRS)

    Gerver, M. J.; Hastings, Daniel E.; Oberhardt, M. R.

    1990-01-01

    Previous theoretical work on plasma contactors as current collectors has fallen into two categories: collisionless double layer theory (describing space charge limited contactor clouds) and collisional quasineutral theory. Ground based experiments at low current are well explained by double layer theory, but this theory does not scale well to power generation by electrodynamic tethers in space, since very high anode potentials are needed to draw a substantial ambient electron current across the magnetic field in the absence of collisions (or effective collisions due to turbulence). Isotropic quasineutral models of contactor clouds, extending over a region where the effective collision frequency upsilon sub e exceeds the electron cyclotron frequency omega sub ce, have low anode potentials, but would collect very little ambient electron current, much less than the emitted ion current. A new model is presented, for an anisotropic contactor cloud oriented along the magnetic field, with upsilon sub e less than omega sub ce. The electron motion along the magnetic field is nearly collisionless, forming double layers in that direction, while across the magnetic field the electrons diffuse collisionally and the potential profile is determined by quasineutrality. Using a simplified expression for upsilon sub e due to ion acoustic turbulence, an analytic solution has been found for this model, which should be applicable to current collection in space. The anode potential is low and the collected ambient electron current can be several times the emitted ion current.

  20. Salt balance: From space experiments to revolutionizing new clinical concepts on earth - A historical review

    NASA Astrophysics Data System (ADS)

    Gerzer, Rupert

    2014-11-01

    For a long time, sodium balance appeared to be a “done deal” and was thought to be well understood. However, experiments in preparation of space missions showed that the concept of osmotic sodium storage and close correlations of sodium with water balance are only part of the regulatory mechanisms of body salt. By now it has turned out that the human skin is an important storage place and regulator for sodium, that sodium storage involves macrophages which in turn salt-dependently co-regulate blood pressure, that body sodium also strongly influences bone and protein metabolism, and that immune functions are also strongly influenced by sodium. In addition, the aging process appears to lead to increased body sodium storage, which in turn might influence the aging process of the human body. The current review article summarizes the developments that have led to these revolutionizing new findings and concepts as well as consequences deriving from these findings. Therefore, it is not intended in this article to give a complete literature overview over the whole field but to focus on such key literature and considerations that led to the respective developments.

  1. Ultralyophobic oxidized aluminum surfaces exhibiting negligible contact angle hysteresis.

    PubMed

    Hozumi, Atsushi; McCarthy, Thomas J

    2010-02-16

    Ultralyophobic oxidized aluminum surfaces exhibiting negligible contact angle hysteresis for probe liquids were prepared by chemical vapor deposition (CVD) of bis((tridecafluoro-1,1,2,2,-tetrahydrooctyl)-dimethylsiloxy)methylsilane (CF(3)(CF(2))(5)CH(2)CH(2)Si(CH(3))(2)O)(2)SiCH(3)H, (R(F)Si(Me)(2)O)(2)SiMeH). Oxidized aluminum surfaces were prepared by photooxidation/cleaning of sputter-coated aluminum on silicon wafers (Si/Al(Al(2)(O(3)))) using oxygen plasma. X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM) confirmed that this facile CVD method produces a monolayer with a thickness of 1.1 nm on the Si/Al(Al(2)(O(3))) surface without a discernible change in surface morphology. After monolayer deposition, the hydrophilic Si/Al(Al(2)(O(3))) surface became both hydrophobic and oleophobic and exhibited essentially no contact angle hysteresis for water and n-hexadecane (advancing/receding contact angles (theta(A)/theta(R)) = 110 degrees/109 degrees and 52 degrees/50 degrees, respectively). Droplets move very easily on this surface and roll off of slightly tilted surfaces, independently of the contact angle (which is a practical definition of ultralyophobic). A conventional fluoroalkylsilane monolayer was also prepared from 1H,1H,2H,2H-perfluorodecyltrimethoxysilane (CF(3)(CF(2))(7)CH(2)CH(2)Si(OCH(3))(3), R(F)Si(OMe)(3)) for comparison. The theta(A)/theta(R) values for water and n-hexadecane are 121 degrees/106 degrees and 76 degrees/71 degrees, respectively. The larger hysteresis values indicate the "pinning" of probe liquids, even though advancing contact angles are larger than those of the (R(F)Si(Me)(2)O)(2)SiMeH-derived monolayers. The (R(F)Si(Me)(2)O)(2)SiMeH-derived monolayers have excellent hydrolytic stability in water. We propose that the (R(F)Si(Me)(2)O)(2)SiMeH-derived monolayers are flexible and liquidlike and that drops in contact with these surfaces experience very low energy barriers between metastable states, leading to the

  2. Practical Work in Earth Sciences Education: an experience with students in the context of a National Science Programme in Portugal

    NASA Astrophysics Data System (ADS)

    Marques, Luis; Praja, Joäo; Thompson, David

    2002-02-01

    The programme Ciencia Viva of the Portuguese Ministry of Science and Technology aims to create a greater understanding of science and science education amongst scientists, teachers, school children and the general public, each of whom is encouraged to cooperate and interact through regular contacts. The purpose is to improve practical, experimental and other forms of investigative work. To accomplish such work in schools, an overview of the state of science education worldwide is presented in terms of old and new traditions of the teaching of the physical and historical sciences the latter including the teaching of fieldwork. Traditional practices are compared with those established recently in various parts of the world in which more carefully considered understanding of the nature of science and science education has been established. In illustration of good practice, an outline is offered of the nature and rationale of two sets of curricular materials. These were designed by a team comprising staff members of the University of Aveiro and secondary school teachers and were trialled in schools. These activities are concerned with the internal rock cycle and the internal energy of the Earth in relation to plate tectonic theory. They are also related to the processes of weathering, erosion, transportation and deposition of sedimentary rocks and structures (like wave and current ripple marks) which were formed as part of the external rock cycle driven by the Sun's energy. The account concludes with an outline of the sub programme 'Geology in Summer', a fieldwork programme which introduces a holistic understanding of the workings of the outer part of the Earth to the general public. Students' perspectives and teachers' views about these experiences are generally very positive and are presented at the end. The whole programme was evaluated by an international team of scientists and science educators.

  3. Laboratory convection experiments with internal, noncontact, microwave generated heating, applied to Earth's mantle dynamics

    NASA Astrophysics Data System (ADS)

    Limare, Angela; Surducan, Emanoil; di Giuseppe, Erika; Surducan, Vasile; Neamtu, Camelia; Vilella, Kenny; Fourel, Loic; Farnetani, Cinzia; Kaminski, Edouard; Jaupart, Claude

    2014-05-01

    boundary that induce a diffuse upward return flow. Within experimental error, excellent agreement was found between calculated and observed vertical profiles of the horizontally-averaged temperature. Calculations and experiments led to the same velocity field characteristics including the number of instabilities in the upper boundary layer and root mean square velocity values. P. J. Tackley, Geophys. Res. Lett. 20, 2187-2190 (1993).

  4. Hysteresis-reduced dynamic displacement control of piezoceramic stack actuators using model predictive sliding mode control

    NASA Astrophysics Data System (ADS)

    Kim, Byeongil; Washington, Gregory N.; Yoon, Hwan-Sik

    2012-05-01

    Currently, piezoelectric actuators are being used in many applications from precision positioning control to active vibration control of large space structures. They can take the form of a solid-state device and are conveniently controlled by a voltage input. In spite of their relative ease of control, positioning accuracy and actuator longevity can be compromised by the hysteresis. Thus, the primary objective of this research is to minimize the hysteretic effect of a piezoelectric actuator in order to obtain a near linear relationship between the input voltage and the output displacement. The reduction of the hysteresis is accomplished by a newly developed control methodology named model predictive sliding mode control. A nonlinear energy-based hysteresis model is developed for a piezoelectric stack actuator and model predictive sliding mode control is applied to force the system state to reach a sliding surface in an optimal manner and track the reference signal accurately thereafter. To validate this new approach, simulations and experiments are conducted and the results highlight significantly improved hysteresis reduction in the displacement control of the piezoelectric stack actuator.

  5. A stability-based mechanism for hysteresis in the walk–trot transition in quadruped locomotion

    PubMed Central

    Aoi, Shinya; Katayama, Daiki; Fujiki, Soichiro; Tomita, Nozomi; Funato, Tetsuro; Yamashita, Tsuyoshi; Senda, Kei; Tsuchiya, Kazuo

    2013-01-01

    Quadrupeds vary their gaits in accordance with their locomotion speed. Such gait transitions exhibit hysteresis. However, the underlying mechanism for this hysteresis remains largely unclear. It has been suggested that gaits correspond to attractors in their dynamics and that gait transitions are non-equilibrium phase transitions that are accompanied by a loss in stability. In the present study, we used a robotic platform to investigate the dynamic stability of gaits and to clarify the hysteresis mechanism in the walk–trot transition of quadrupeds. Specifically, we used a quadruped robot as the body mechanical model and an oscillator network for the nervous system model to emulate dynamic locomotion of a quadruped. Experiments using this robot revealed that dynamic interactions among the robot mechanical system, the oscillator network, and the environment generate walk and trot gaits depending on the locomotion speed. In addition, a walk–trot transition that exhibited hysteresis was observed when the locomotion speed was changed. We evaluated the gait changes of the robot by measuring the locomotion of dogs. Furthermore, we investigated the stability structure during the gait transition of the robot by constructing a potential function from the return map of the relative phase of the legs and clarified the physical characteristics inherent to the gait transition in terms of the dynamics. PMID:23389894

  6. A stability-based mechanism for hysteresis in the walk-trot transition in quadruped locomotion.

    PubMed

    Aoi, Shinya; Katayama, Daiki; Fujiki, Soichiro; Tomita, Nozomi; Funato, Tetsuro; Yamashita, Tsuyoshi; Senda, Kei; Tsuchiya, Kazuo

    2013-04-06

    Quadrupeds vary their gaits in accordance with their locomotion speed. Such gait transitions exhibit hysteresis. However, the underlying mechanism for this hysteresis remains largely unclear. It has been suggested that gaits correspond to attractors in their dynamics and that gait transitions are non-equilibrium phase transitions that are accompanied by a loss in stability. In the present study, we used a robotic platform to investigate the dynamic stability of gaits and to clarify the hysteresis mechanism in the walk-trot transition of quadrupeds. Specifically, we used a quadruped robot as the body mechanical model and an oscillator network for the nervous system model to emulate dynamic locomotion of a quadruped. Experiments using this robot revealed that dynamic interactions among the robot mechanical system, the oscillator network, and the environment generate walk and trot gaits depending on the locomotion speed. In addition, a walk-trot transition that exhibited hysteresis was observed when the locomotion speed was changed. We evaluated the gait changes of the robot by measuring the locomotion of dogs. Furthermore, we investigated the stability structure during the gait transition of the robot by constructing a potential function from the return map of the relative phase of the legs and clarified the physical characteristics inherent to the gait transition in terms of the dynamics.

  7. Acoustic emission, domain walls and hysteresis in YIG

    NASA Astrophysics Data System (ADS)

    Guyot, M.; Merceron, T.; Cagan, V.

    1987-02-01

    The acoustic emission (AE) is experimentally shown to vary along the hysteresis loop of YIG samples with the creation and/or annihilation of domain walls. The AE and the Barkhausen activities are in anticorrelation. AE and hysteresis losses are proportional, which could mean that AE is the fundamental step to convert magnetic energy into heat.

  8. Grain-damage hysteresis and plate tectonic states

    NASA Astrophysics Data System (ADS)

    Bercovici, David; Ricard, Yanick

    2016-04-01

    deforms at a given stress can acquire two stable deformation regimes indicative of plate-like flows, i.e., it permits the coexistence of both slowly deforming plate interiors, and rapidly deforming plate boundaries. Earth seems to exist squarely inside the hysteresis loop and thus can have coexisting deformation states, while Venus appears to straddle the end of the loop where only the weakly deforming branch exists.

  9. A Hysteresis Model for Piezoceramic Materials

    NASA Technical Reports Server (NTRS)

    Smith, Ralph C.; Ounaies, Zoubeida

    1999-01-01

    This paper addresses the modeling of nonlinear constitutive relations and hysteresis inherent to piezoceramic materials at moderate to high drive levels. Such models are, necessary to realize the, full potential of the materials in high performance control applications, and a necessary prerequisite is the development of techniques which permit control implementation. The approach employed here is based on the qualification of reversible and irreversible domain wall motion in response to applied electric fields. A comparison with experimental data illustrates that because the resulting ODE model is physics-based, it can be employed for both characterization and prediction of polarization levels throughout the range of actuator operation. Finally, the ODE formulation is amenable to inversion which facilitates the development of an inverse compensator for linear control design.

  10. Positive hysteresis of Ce-doped GAGG scintillator

    NASA Astrophysics Data System (ADS)

    Yanagida, Takayuki; Fujimoto, Yutaka; Koshimizu, Masanori; Watanabe, Kenichi; Sato, Hiroki; Yagi, Hideki; Yanagitani, Takagimi

    2014-10-01

    Positive hysteresis and radiation tolerance to high-dose radiation exposure were investigated for Ce 1% and 3% doped Gd3(Al, Ga)5O12 (Ce:GAGG) crystal scintillator on comparison with other garnet scintillators such Ce:YAG, Ce:LuAG, Pr:LuAG, and ceramic Ce:GAGG. When they were irradiated by several Gy 60Co γ-rays, Ce 1% doped GAGG crystal exhibited ∼20% light yield enhancement (positive hysteresis). This is the first time to observe positive hysteresis in Ce doped GAGG. On the other hand, other garnet materials did not show the positive hysteresis and their light yields were stable after 800 Gy irradiation except Pr:LuAG. The light yield of Pr:LuAG decreased largely. When irradiated Ce:GAGG which showed positive hysteresis was evaluated in Synchrotron facility (UVSOR), new excitation band was created around 60 nm.

  11. Coexistence of negative photoconductivity and hysteresis in semiconducting graphene

    NASA Astrophysics Data System (ADS)

    Zhuang, Shendong; Chen, Yan; Xia, Yidong; Tang, Nujiang; Xu, Xiaoyong; Hu, Jingguo; Chen, Zhuo

    2016-04-01

    Solution-processed graphene quantum dots (GQDs) possess a moderate bandgap, which make them a promising candidate for optoelectronics devices. However, negative photoconductivity (NPC) and hysteresis that happen in the photoelectric conversion process could be harmful to performance of the GQDs-based devices. So far, their origins and relations have remained elusive. Here, we investigate experimentally the origins of the NPC and hysteresis in GQDs. By comparing the hysteresis and photoconductance of GQDs under different relative humidity conditions, we are able to demonstrate that NPC and hysteresis coexist in GQDs and both are attributed to the carrier trapping effect of surface adsorbed moisture. We also demonstrate that GQDs could exhibit positive photoconductivity with three-order-of-magnitude reduction of hysteresis after a drying process and a subsequent encapsulation. Considering the pervasive moisture adsorption, our results may pave the way for a commercialization of semiconducting graphene-based and diverse solution-based optoelectronic devices.

  12. Coexistence of negative photoconductivity and hysteresis in semiconducting graphene

    SciTech Connect

    Zhuang, Shendong; Tang, Nujiang; Chen, Zhuo; Chen, Yan; Xia, Yidong; Xu, Xiaoyong; Hu, Jingguo

    2016-04-15

    Solution-processed graphene quantum dots (GQDs) possess a moderate bandgap, which make them a promising candidate for optoelectronics devices. However, negative photoconductivity (NPC) and hysteresis that happen in the photoelectric conversion process could be harmful to performance of the GQDs-based devices. So far, their origins and relations have remained elusive. Here, we investigate experimentally the origins of the NPC and hysteresis in GQDs. By comparing the hysteresis and photoconductance of GQDs under different relative humidity conditions, we are able to demonstrate that NPC and hysteresis coexist in GQDs and both are attributed to the carrier trapping effect of surface adsorbed moisture. We also demonstrate that GQDs could exhibit positive photoconductivity with three-order-of-magnitude reduction of hysteresis after a drying process and a subsequent encapsulation. Considering the pervasive moisture adsorption, our results may pave the way for a commercialization of semiconducting graphene-based and diverse solution-based optoelectronic devices.

  13. Hysteresis Compensation for a Piezo Deformable Mirror - Poster Paper

    NASA Astrophysics Data System (ADS)

    Song, H.; Fraanje, R.; Schitter, G.; Verhaegen, M.; Vdovin, G.

    2008-01-01

    The field of adaptive optics (AO) has received rapidly increasing attention in recent years, the intrinsic hysteresis of the piezo deformable mirror (DM) imposes a limit in the accuracy when the stroke of the piezo-actuator is on the order of micrometers. This contribution discusses the hysteresis compensation of a piezo DM by an inverse Preisach hysteresis model. The inverse Preisach hysteresis model is identified from the measured input-output data with a neural network and with a hinging hyperplane based approach. Experimental results demonstrate that hysteresis of the piezo-actuator can be reduced from 20% to about 6% and 9% by the neural network and by the hinging hyperplanes, respectively.

  14. Mechanism of Wettability Hysteresis in Natural Soils

    NASA Astrophysics Data System (ADS)

    Ryder, J. L.; Demond, A. H.

    2006-12-01

    Because models of subsurface flow and transport depend on the contact angles made by the air/water and waste liquid/water interfaces with soil and rock surfaces, accurate knowledge of the wettability of subsurface systems is necessary. Sessile drop contact angles were measured on dry rock surfaces and on the same rock surfaces immersed in a second fluid. Quartz slides and cut rock faces that had been leveled and polished served as representative surfaces for silica sand, talc, kerogen containing shales, bituminous coal, and mineralized carbon. For several carbon-containing materials, contact angles are reversed from near 170 degrees when water is the receding fluid to less than 70 degrees if water is the advancing fluid. However, some mineral soils do not display wetting reversal. This work seeks to explain the mechanisms of the wetting order hysteresis. Utilizing an aqueous 0.01 M NaCl solution, glycerol, 1-bromonapthalene, and diidomethane as probe fluids, contact angle values are assessed with the method of van Oss et al. (1988) to determine the surface energy components of each type of soil. The quartz mineral surface energy has a large polar component and the calculated quartz surface energy does not depend on the wetting history of the slide. However, the magnitudes of the surface energy components of the carbon-containing materials change depending on the wetting history, indicating that the nature of the surface is altered by the surrounding fluid. The presence of wetting order hysteresis may contribute to the heterogeneous fluid distributions found at many waste liquid sites. When soil is known to contain carbon, some knowledge of the wetting history is necessary to predict the contact angle and thus the transport behavior.

  15. Contact angle hysteresis on superhydrophobic stripes.

    PubMed

    Dubov, Alexander L; Mourran, Ahmed; Möller, Martin; Vinogradova, Olga I

    2014-08-21

    We study experimentally and discuss quantitatively the contact angle hysteresis on striped superhydrophobic surfaces as a function of a solid fraction, ϕS. It is shown that the receding regime is determined by a longitudinal sliding motion of the deformed contact line. Despite an anisotropy of the texture the receding contact angle remains isotropic, i.e., is practically the same in the longitudinal and transverse directions. The cosine of the receding angle grows nonlinearly with ϕS. To interpret this we develop a theoretical model, which shows that the value of the receding angle depends both on weak defects at smooth solid areas and on the strong defects due to the elastic energy of the deformed contact line, which scales as ϕS(2)lnϕS. The advancing contact angle was found to be anisotropic, except in a dilute regime, and its value is shown to be determined by the rolling motion of the drop. The cosine of the longitudinal advancing angle depends linearly on ϕS, but a satisfactory fit to the data can only be provided if we generalize the Cassie equation to account for weak defects. The cosine of the transverse advancing angle is much smaller and is maximized at ϕS ≃ 0.5. An explanation of its value can be obtained if we invoke an additional energy due to strong defects in this direction, which is shown to be caused by the adhesion of the drop on solid sectors and is proportional to ϕS(2). Finally, the contact angle hysteresis is found to be quite large and generally anisotropic, but it becomes isotropic when ϕS ≤ 0.2.

  16. Modified Davidenkov hysteresis and the propagation of sawtooth waves in polycrystals with hysteresis loss saturation

    NASA Astrophysics Data System (ADS)

    Nazarov, V. E.; Kiyashko, S. B.

    2016-08-01

    A modified Davidenkov hysteresis equation of the state has been proposed for describing the saturation of the effects of amplitude-dependent internal friction in polycrystalline metals and other solids, which possess imperfect elasticity. Using this equation, an exact analytical solution of the problem of the propagation of a periodic sawtooth wave in media characterized by quadratic hysteresis with nonlinear loss saturation has been obtained. Regularities of variations in the characteristics of a sawtooth wave, such as nonlinear loss, the change in the velocity of the propagation of the wave, and the amplitudes of the higher harmonics of the wave, have been determined. A graphical analysis of the evolution of the shape and the spectral components of the wave has been carried out.

  17. Experiences in Bridging the Gap Between Science and Decision Making at NASAs GSFC Earth Sciences Data and Information Services Center (GES DISC)

    NASA Astrophysics Data System (ADS)

    Kempler, S.; Teng, W.; Friedl, L.; Lynnes, C.

    2008-12-01

    In recognizing the significance of NASA remote sensing Earth science data in monitoring and better understanding our planet's natural environment, NASA has implemented the 'Decision Support Through Earth Science Research Results' program to solicit "proposals that develop and demonstrate innovative and practicable applications of NASA Earth science observations and research"that focus on improving decision making activities", as stated in the NASA ROSES-2008, A.18 solicitation. This very successful program has yielded several monitoring, surveillance, and decision support systems through collaborations with benefiting organizations in the areas of agriculture, air quality, disaster management, ecosystems, public health, water resources, and aviation weather. The Goddard Space Flight Center (GSFC) Earth Sciences Data and Information Services Center (GES DISC) has participated in this program on two projects (one complete, one ongoing), and has had opportune ad hoc collaborations gaining much experience in the formulation, management, development, and implementation of decision support systems utilizing NASA Earth science data. Coupling this experience with the GES DISC's total understanding and vast experience regarding Earth science missions and resulting data and information, including data structures, data usability and interpretation, data interoperability, and information management systems, the GES DISC is in the unique position to more readily identify challenges that come with bringing science data to decision makers. These challenges consist of those that can be met within typical science data usage frameworks, as well as those challenges that arise when utilizing science data for previously unplanned applications, such as decision support systems. The purpose of this presentation is to share GES DISC decision support system project experiences in regards to system sustainability, required data quality (versus timeliness), data provider understanding how

  18. The EOS Aqua/Aura Experience: Lessons Learned on Design, Integration, and Test of Earth-Observing Satellites

    NASA Technical Reports Server (NTRS)

    Nosek, Thomas P.

    2004-01-01

    NASA and NOAA earth observing satellite programs are flying a number of sophisticated scientific instruments which collect data on many phenomena and parameters of the earth's environment. The NASA Earth Observing System (EOS) Program originated the EOS Common Bus approach, which featured two spacecraft (Aqua and Aura) of virtually identical design but with completely different instruments. Significant savings were obtained by the Common Bus approach and these lessons learned are presented as information for future program requiring multiple busses for new diversified instruments with increased capabilities for acquiring earth environmental data volume, accuracy, and type.

  19. Ras Labs-CASIS-ISS NL experiment for synthetic muscle returned to Earth: resistance to ionizing radiation

    NASA Astrophysics Data System (ADS)

    Rasmussen, Lenore; Albers, Leila N.; Rodriguez, Simone; Gentile, Charles; Meixler, Lewis D.; Ascione, George; Hitchner, Robert; Taylor, James; Hoffman, Dan; Cylinder, David; Gaza, Ramona; Moy, Leon; Mark, Patrick S.; Prillaman, Daniel L.; Nodarse, Robert; Menegus, Michael J.; Ratto, Jo Ann; Thellen, Christopher T.; Froio, Danielle; Valenza, Logan; Poirier, Catherine; Sinkler, Charles; Corl, Dylan; Hablani, Surbhi; Fuerst, Tyler; Gallucci, Sergio; Blocher, Whitney; Liffland, Stephanie

    2017-04-01

    In anticipation of deep space travel, new materials are being explored to assist and relieve humans in dangerous environments, such as high radiation, extreme temperature, and extreme pressure. Ras Labs Synthetic Muscle™ - electroactive polymers (EAPs) that contract and expand at low voltages - which mimic the unique gentle-yet-strong nature of human tissue, is a potential asset to manned space travel through protective gear and human assist robotics and for unmanned space exploration through deep space. Gen 3 Synthetic Muscle™ was proven to be resistant to extreme temperatures, and there were indications that these materials would also be radiation resistant. The purpose of the Ras Labs-CASIS-ISS Experiment was to test the radiation resistivity of the third and fourth generation of these EAPs, as well as to make them even more radiation resistant. On Earth, exposure of the Generation 3 and Generation 4 EAPs to a Cs-137 radiation source for 47.8 hours with a total dose of 305.931 kRad of gamma radiation was performed at the US Department of Energy's Princeton Plasma Physics Laboratory (PPPL) at Princeton University, followed by pH, peroxide, Shore Hardness durometer, and electroactivity testing to determine the inherent radiation resistivity of these contractile EAPs, and to determine whether the EAPs could be made even more radiation resistant through the application of appropriate additives and coatings. The on Earth preliminary tests determined that selected Ras Labs EAPs were not only inherently radiation resistant, but with the appropriate coatings and additives, could be made even more radiation resistant. G-force testing to over 10 G's was performed at US Army's ARDEC Labs, with excellent results, in preparation for space flight to the International Space Station National Laboratory (ISS-NL). Selected samples of Generation 3 and Generation 4 Synthetic Muscle™, with various additives and coatings, were launched to the ISS-NL on April 14, 2015 on the

  20. Radiometer offsets and count conversion coefficients for the Earth Radiation Budget Experiment (ERBE) spacecraft for the years 1984, 1985, and 1986

    NASA Technical Reports Server (NTRS)

    Paden, Jack; Pandey, Dhirendra K.; Shivakumar, Netra D.; Stassi, Joseph C.; Wilson, Robert; Bolden, William; Thomas, Susan; Gibson, M. Alan

    1991-01-01

    A compendium is presented of the ground and inflight scanner and nonscanner offsets and count conversion (gain) coefficients used for the Earth Radiation Budget Experiment (ERBE) production processing of data from the ERBS, NOAA-9, and NOAA-10 satellites for the 1 Nov. 1984 to 31 Dec. 1986.