Science.gov

Sample records for earth hysteresis experiment

  1. 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.

  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. 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

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. EAGLE: Earth Action Guardian Leadership Experiences.

    ERIC Educational Resources Information Center

    Indiana State Dept. of Education, Indianapolis. Center for School Improvement and Performance.

    This publication shares ideas, exemplary programs, resources, and schools involved in the 1993-1994 EARTH FOREVER program sponsored by the Indiana Department of Education. Educators and students are challenged to plan activities and develop similar Earth Action Guardian Leadership Experiences (EAGLE) programs. Sixteen elementary, middle, and high…

  9. Hysteresis in particulate recording media. Experiment and simulation with Preisach and Jiles-Atherton models

    NASA Astrophysics Data System (ADS)

    Andrei, Petru; Stancu, Alexandru

    1999-12-01

    In order to describe the magnetisation processes in particulate media some new variants for the Jiles-Atherton model are developed. The differences between these models and the Preisach model are discussed. Due to the analogy between the parameters of the two model's, the Jiles-Atherton model's parameters may be determined using the Preisach model's identification methods. A good agreement between the simulated and the measured data is observed for the major hysteresis loop but it is no longer good for some more complex magnetisation processes.

  10. 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.

  11. 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.

  12. 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. PMID:26986327

  13. Clouds and the Earth`s radiant energy system (CERES): An Earth observing system experiment

    SciTech Connect

    Wielicki, B.A.; Barkstrom, B.R.; Harrison, E.F.

    1996-05-01

    Clouds and the Earth`s Radiant Energy System (CERES) is an investigation to examine the role of cloud/radiation feedback on the Earth`s climate system. The CERES broadband scanning radiometers are an improved version of the Earth`s 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. 62 refs., 10 figs., 3 tabs.

  14. 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.

  15. The Earth's velocity for direct detection experiments

    NASA Astrophysics Data System (ADS)

    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.

  16. 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.

  17. Mathematical models of hysteresis

    SciTech Connect

    1998-08-01

    The 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 (not the entire input variations) 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. The origin of such tools can be traced back to the landmark paper of Preisach. Their 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. During the past four years, the study has been by and large centered around the following topics: (1) further development of Scalar and vector Preisach-type models of hysteresis; (2) experimental testing of Preisach-type models of hysteresis; (3) development of new models for viscosity (aftereffect) in hysteretic systems; (4) development of mathematical models for superconducting hysteresis in the case of gradual resistive transitions; (5) software implementation of Preisach-type models of hysteresis; and (6) development of new ideas which have emerged in the course of the research work. The author briefly describes the main scientific results obtained in the areas outlined above.

  18. Decadal Prediction Experiments using EC-EARTH

    NASA Astrophysics Data System (ADS)

    Wouters, Bert; Hazeleger, Wilco; van Oldenborgh, Geert Jan

    2010-05-01

    We present the first results of decadal prediction experiments with EC-EARTH 2.1 in the framework of the EU-THOR project. This model consists of the ECMWF IFSc31 model at T159/L62 resolution, the NEMO2 ocean model at 1° resolution and the LIM2 sea-ice model. The purpose is to predict decadal variability in the Atlantic Ocean and the resulting predictability in the weather at these time scales. As expected, the model shows a bias in the first years due to the initialization shock from the full initial state (NEMOVAR), but stabilizes afterwards. The bias and first estimates of the skill are shown for a partial CMIP5 ensemble, covering ocean, surface and atmospheric components of the coupled model.

  19. [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.

  20. 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.

  1. 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

  2. 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.

  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. 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.

  5. 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.

  6. Field-Based Research Experience in Earth Science Teacher Education.

    ERIC Educational Resources Information Center

    O'Neal, Michael L.

    2003-01-01

    Describes the pilot of a field-based research experience in earth science teacher education designed to produce well-prepared, scientifically and technologically literate earth science teachers through a teaching- and research-oriented partnership between in-service teachers and a university scientist-educator. Indicates that the pilot program was…

  7. 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)

  8. Astronaut Gerald Carr trains with Earth Resources Experiments Package

    NASA Technical Reports Server (NTRS)

    1973-01-01

    Astronaut Gerald P. Carr, Skylab 4 commander, changes a dial on the control and display panel for the Earth Resources Experiments package (EREP) during a training exercise in the Multiple Docking Adapter (MDA) one-G trainer at JSC.

  9. Experience our Planet - Interpreting Earth Sciences in a Museum Environment

    NASA Astrophysics Data System (ADS)

    Schneider, S.

    2012-12-01

    Earth science interpretation is more than giving your audience facts and figures. It is about relating Earth sciences to something within the personality or experience of your audience. It is about revelation based on information rather than just giving away information per se. And: The chief aim of interpretation is not instruction but provocation. A great environment for Earth science interpretation is a museum. Whether it is an art gallery, a technology exhibition or a national park's visitor center is irrelevant. Earth science interpretation is possible everywhere and sometimes even more successful in unsuspected locations than in natural history museums. Earth sciences have just started to use the potential which lies within museum environments. A historic view on Earth sciences and natural hazard research can be given in art galleries. The technology used in research can be showcased and - sometimes - even tested in science centers and technology museums. National Parks provide the best opportunity to actually experience the dynamic planet Earth live. This talk aims towards giving an insight view on how to conduct interpretive programs in museums, how to utilize the treasures and possibilities provided by museums and national parks and to encourage scientists to go to these places for face-to-face Earth science interpretation.

  10. 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. PMID:22588784

  11. 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.

  12. 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.

  13. Astronaut Edward Gibson trains with Earth Resources Experiments Package

    NASA Technical Reports Server (NTRS)

    1973-01-01

    Scientist-Astronaut Edward G. Gibson, Skylab 4 science pilot, turns on a switch on the control box of the S190B camera, one of the components of the Earth Resources Experiments Package (EREP). The single lens Earth Terrain Camera takes five-inch photographs. Behind Gibson is the stowed suits of Astronaut Gerald P. Carr, commander for the third manned mission. The exercise took place in the Orbital Workshop one-G trainer at JSC.

  14. 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.

  15. 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

  16. 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…

  17. 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…

  18. 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.

  19. Grid systems for Earth radiation budget experiment applications

    NASA Technical Reports Server (NTRS)

    Brooks, D. R.

    1981-01-01

    Spatial coordinate transformations are developed for several global grid systems of interest to the Earth Radiation Budget Experiment. The grid boxes are defined in terms of a regional identifier and longitude-latitude indexes. The transformations associate longitude with a particular grid box. The reverse transformations identify the center location of a given grid box. Transformations are given to relate the rotating (Earth-based) grid systems to solar position expressed in an inertial (nonrotating) coordinate system. The FORTRAN implementations of the transformations are given, along with sample input and output.

  20. 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). PMID:24522597

  1. The Earth System Science Education Experience: Personal Vignettes

    NASA Astrophysics Data System (ADS)

    Ruzek, M.; Aron, J.; Maranto, G.; Reider, D.; Wake, C.

    2006-12-01

    Colleges and universities across the country and around the world have embraced the Earth system approach to gain deeper understanding of the interrelationships of processes that define the home planet. The Design Guide for Undergraduate Earth System Science Education, a product of the NASA/USRA Earth System Science Education for the 21st Century Program (ESSE 21), represents a synthesis of community understanding of the content and process of teaching and learning about Earth as a system. The web-based Design Guide serves faculty from multiple disciplines who wish to adopt an ESS approach in their own courses or programs. Illustrating the nine topical sections of the Design Guide are a series of short vignettes telling the story of how ESS is being used in the classroom, how ESS has contributed to institutional change and personal professional development, how ESS is being implemented at minority serving institutions, and the impact of ESS education on student research. Most vignettes are written from a personal perspective and reflect a direct experience with Earth System Science Education. Over forty vignettes have been assembled aiming to put a face on the results of the systemic reform efforts of the past fifteen years of the ESSE programs, documenting the sometimes intangible process of education reform to be shared with those seeking examples of ESS education. The vignettes are a vital complement to the Design Guide sections, and are also available as a separate collection on the Design Guide and ESSE 21 web sites.

  2. Mechanisms of magnetic and temperature hysteresis in ErFeO3 and TmFeO3 single crystals

    NASA Astrophysics Data System (ADS)

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

    2010-10-01

    Magnetic hysteresis is studied in the orthoferrites ErFeO3 and TmFeO3 using the single crystal samples of millimeter dimensions. It is shown that in both materials one observes a temperature transition manifesting itself through the temperature hysteresis of the magnetic moment and a peculiar temperature evolution of the field hysteresis loop shapes near this transition. Experiments rule out the hypothesis that the ordering of the orthoferrite's rare-earth magnetic moments plays an important role in these phenomena. The hysteresis curves can be explained by a few-domain magnetic state of the samples that results from the weak ferromagnetism of the orthoferrites. The phenomenon is generic for weak ferromagnets with temperature dependent magnetization. A large characteristic magnetic length makes the behavior of the relatively big samples analogous to that observed in the nanosize samples of strong ferromagnets.

  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. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2014-10-01

    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.

  6. 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.

  7. First data from the earth radiation budget experiment (ERBE)

    NASA Technical Reports Server (NTRS)

    Barkstrom, B. R.; Harrison, E. F.; Huck, F. O.; Smith, G. L.; Berroir, A.; Cess, R. D.; Gruber, A.; Hartmann, D. L.; King, M. D.; Mecherikunnel, A. T.

    1986-01-01

    The first data obtained from the Earth Radiation Budget Experiment (ERBE) are presented. These data include emitted infrared radiation, albedo, and estimated scene types for Nov. 15, 1984, as well as measurements of the 'solar constant'. Images from the GOES on the same day are included for comparison with the ERBE scene identification. On an instantaneous basis, clouds appear colder and more reflective than seems to have been noted before. The experiment data will be applied to several key studies of cloud-radiation-climate interactions.

  8. 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.

  9. 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.

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

    PubMed

    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. PMID:27587138

  11. 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.

  12. 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.

  13. 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.

  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. 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.

  16. Little Earth Experiment: A model to study the flow in the Earth's Tangent Cylinder

    NASA Astrophysics Data System (ADS)

    Aujogue, Kelig; Potherat, Alban; Sreenivasan, Binod

    2016-04-01

    We present a new experimental set-up developed to model the flow in the Earth's Tangent Cylinder (TC). This flow is known to have important consequences for the Earth's magnetic field and the drift of its north pole. For the first time, our experiment allows to reproduce the interplay between the magnetic, Coriolis and buoyancy forces inside a transparent electrically conducting liquid in an Earth-like geometry. The novelty of our experiment lies in the study of convection in a hemisphere heated on the inside and cooled on the outside, filled with sulphuric acid and permeated by a large magnetic field. The experimental apparatus can provide data at Ekman number E (ratio of the viscous force to the Coriolis force) of the order of 10‑4 to 10‑5, Elsasser number Λ (ratio of the Lorentz force to the Coriolis force) of the order of 0.1 to 1 and Rayleigh number (ratio of buoyancy to viscous forces) in the range of the critical Rayleigh number Rac to 20 × Rac. With the help of particle image velocimetry (PIV) and thermal measurement, we compare the onset of convection and supercritical flow regimes between a purely hydrodynamic system and a magnetohydrodynamic system. For cases without magnetic field, we recover well-established scaling for the onset of convection under rotation; moreover, we obtain thermal wind scalings for supercritical flows. With magnetic field, we study the thermal behaviour by measurement of the Nusselt number and the Rayleigh number as well as magnetoconvective patterns inside the TC.

  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. 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. PMID:26721395

  19. 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

  20. 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

  1. 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.

  2. The Earth Radiation Budget Experiment - Early validation results

    NASA Technical Reports Server (NTRS)

    Smith, G. L.; Barkstrom, B. R.; Harrison, E. F.; Huck, F. O.; Cess, R.; Coakley, J.; Duncan, C.; King, M.; Mecherikunnel, A.; Gruber, A.

    1986-01-01

    The primary techniques used to obtain and validate the data of the Earth Radiation Budget Experiment (ERBE) are described, together with preliminary results of the validation. The ERBE consists of radiometers aboard the ERB Satellite, dedicated to a 57-deg orbit, and each of the two NOAA meteorological spacecraft (NOAA 9 and NOAA G) in near polar orbits. The radiometers include scanning narrow field-of-view (FOV) and nadir-looking wide and medium FOV radiometers, and a solar monitoring channel. Measurements of the solar constant by the solar monitors, and the wide and medium FOV radiometers of the ERB and the NOAA 9 spacecraft agree within a fraction of a percent. Comparison of the wide and medium FOV radiometers with the scanning radiometers showed an agreement of 1 to 4 percent. The multiple ERBE satellites are acquiring the first global measurements of regional scale-diurnal variations in the earth's radiation budget. These were verified by comparison with the high-temporal-resolution geostationary satellite data.

  3. 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. PMID:27110836

  4. Hysteresis compensation and trajectory preshaping for piezoactuators in scanning applications

    NASA Astrophysics Data System (ADS)

    Liu, Yanfang; Shan, Jinjun; Gabbert, Ulrich; Qi, Naiming

    2014-01-01

    This paper focuses on the dynamics and control of piezoactuators (PEAs) for high-speed large-range scanning applications. Firstly, the nonlinear hysteresis is modeled by using a modified Maxwell resistive capacitor (MRC) model. Secondly, an inverse-based feedforward controller is proposed for this application with hysteresis compensation. Then, the scanning trajectories are preshaped by treating the hysteresis-compensated PEA as a linear system. Finally, experiments are conducted to verify the effectiveness of the proposed approaches.

  5. Hail Growth Hysteresis.

    NASA Astrophysics Data System (ADS)

    Johnson, David B.; Rasmussen, Roy M.

    1992-12-01

    The transition between wet and dry growth for graupel and hail is examined, and new figures are presented illustrating the critical water contents necessary for transitions into or out of the wet-growth regime. These figures are extended to smaller sizes and lower bulk densities than considered in previous studies. In addition, the possibility of hysteresis in the transitions is examined.

  6. Unveiling magnetic Hysteresis

    NASA Astrophysics Data System (ADS)

    Mellado, Paula; Concha, Andres; Aguayo, David

    Hysteresis manifests as the lack of retraceability of the magnetization curve in magnetic systems. It has been associated with rotation of magnetization and changes of magnetic domains. However, up to date there has been no realization that allows to separate these coupled mechanisms. We introduce a minimal magnetic system where hysteresis is realized in a simple and minimal fashion. The basic units are a few U(1) ferromagnetic altitudinal rotors placed along a one dimensional chain. They exhibit a dissipative dynamics, interacting via magnetic coupling among them and via Zeeman interaction with the external magnetic field. The system displays a hysteretic behavior starting with N=2 rotors which remains qualitatively invariant as more magnets are added to the chain. We explain this irreversibility by using a model that includes Coulombic interactions between magnetic charges located at the ends of the magnets, zeeman coupling and viscous dissipation. We show that interactions between the unit components is the key element responsible for hysteresis and find that the ability to perceive hysteresis, depends on how the time frequencies of damping and interactions inherent to the system compare with the time frequency set by the external field ramping rate.

  7. 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.

  8. 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.

  9. 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.

  10. 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

  11. 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

  12. Hysteresis of transient populations in absorbing-state systems

    NASA Astrophysics Data System (ADS)

    Kapitanchuk, Oleksiy L.; Marchenko, Oleksij M.; Teslenko, Victor I.

    2016-06-01

    A nonequilibrium density matrix theory is used in order to explicitly describe the hysteresis interrelation between populations of nonstationary states in an absorbing multi-stage chain system in the one-particle approximation. As an illustrative example, we restrict ourselves to consideration of the 3-stage absorbing case for which we identify three types of the hysteresis; that is, the causal time dependent hysteresis with leaf-like and triangle-like closed loops, the hidden hysteresis with broken-line loops and the true hysteresis with open loops. Furthermore, we observe a common critical threshold for the hysteresis types and ascertain a reciprocal correspondence of this threshold as between the types as well with the experiment.

  13. 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.

  14. 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.

  15. Earth

    NASA Technical Reports Server (NTRS)

    Carr, M. H.

    1984-01-01

    The following aspects of the planet Earth are discussed: plate tectonics, the interior of the planet, the formation of the Earth, and the evolution of the atmosphere and hydrosphere. The Earth's crust, mantle, and core are examined along with the bulk composition of the planet.

  16. 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.

  17. 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)

  18. 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.

  19. 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.

  20. 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.

  1. The S-193 radar altimeter experiment. [onboard Skylab for earth surface profile measurement

    NASA Technical Reports Server (NTRS)

    Mcgoogan, J. T.; Miller, L. S.; Brown, G. S.; Hayne, G. S.

    1974-01-01

    The Skylab S-193 altimeter experiment utilizes a 10- and 100-ns pulse length, 13.9-GHz earth-pointed radar system to obtain earth-surface backscatter measurements from the Skylab spacecraft. Objectives of the experiment are to obtain precision measurements of surface profile for uses in geodesy, oceanography, and earth physics, and to measure radar-signal characteristics from an earth-orbit geometry to provide design information for future radar remote-sensors. The technical approach is that of measuring the power impulse response of the scattering surface. The hardware is designed to operate in five modes: waveform or impulse-response measurement and altitude determination; radar cross-section experiment; signal correlation experiment; 10-nsec pulse-compression evaluation; and nadir-seeker experiment.

  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. Macroscopic theory for capillary-pressure hysteresis.

    PubMed

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

    2015-03-01

    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. PMID:25646688

  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. 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.

  6. 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.

  7. 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

  8. 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.

  9. 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.

  10. Gay, lesbian, bisexual and transgendered (GLBT) experiences with Earth-spirited faith.

    PubMed

    Smith, Brandy; Horne, Sharon

    2007-01-01

    Earth-spirited faiths (e.g., Pagan and Wiccan spiritualities) have been described as more affirmative toward gay, lesbian, bisexual, and transgendered (GLBT) members than mainstream Judeo-Christian faiths, but no research has explored Earth-spirited faiths' GLBT-affirming behaviors. This study investigated those behaviors as well as the faith experiences of GLBT Earth-spirited individuals. At time of coming out, participants who were affiliated with mainstream Judeo-Christian faiths reported greater faith conflict than those affiliated with Earth-spirited faiths; however, there were no differences in resolution of the conflict between the two groups, internalized homonegativity, or self-acceptance. In addition, Earth-spirited faiths engaged in many GLBT-affirming behaviors. PMID:17594979

  11. 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'. PMID:27402928

  12. 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.

  13. 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.

  14. 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.

  15. 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.

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

    NASA Astrophysics Data System (ADS)

    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.

    2015-05-01

    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.

  17. Hysteresis modeling of clamp band joint with macro-slip

    NASA Astrophysics Data System (ADS)

    Qin, Zhaoye; Cui, Delin; Yan, Shaoze; Chu, Fulei

    2016-01-01

    Clamp band joints are commonly used to connect spacecrafts with launch vehicles. Due to the frictional slippage between the joint components, hysteresis behavior might occur at joint interfaces under cyclic loading. The joint hysteresis will bring friction damping into the launching systems. In this paper, a closed-form hysteresis model for the clamp band joint is developed based on theoretical and numerical analyses of the interactions of the joint components. Then, the hysteresis model is applied to investigating the dynamic response of a payload fastened by the clamp band joint, where the nonlinearity and friction damping effects of the joint is evaluated. The proposed analytical model, which is validated by both finite element analyses and quasi-static experiments, has a simple form with sound accuracy and can be incorporated into the dynamic models of launching systems conveniently.

  18. 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

    2016-01-01

    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. PMID:27611737

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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…

  5. 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.

  6. 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.

  7. Causes and implications of colloid and microorganism retention hysteresis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  8. 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.

  9. Hysteresis in rotation magnetic field

    NASA Astrophysics Data System (ADS)

    Ivanyi, Amalia

    2000-01-01

    The different properties of the vector Jiles-Atherton hysteresis operator is proved under forced H- and B-field supply. Feeding the magnetic material with alternating and circular polarised rotational excitation, the different properties of the model under the input field intensity and the flux density are investigated and the results are proved in figures.

  10. 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.

  11. 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.

  12. 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.

  13. Hysteresis in quartz resonators-a review.

    PubMed

    Kusters, J A; Vig, J R

    1991-01-01

    The literature on the frequency versus temperature characteristics of quartz crystal resonators is reviewed. Three papers that deal with frequency versus pressure hysteresis are included, as these may possibly have relevance to frequency versus temperature hysteresis. It is seen that the causes of hysteresis are not well understood. The evidence to date is inconclusive. The mechanisms that can cause hysteresis include: strain changes changes in the quartz, contamination redistribution, oscillator circuitry hysteresis, and apparent hysteresis due to thermal gradients. The results to date seem to indicate that lattice defects are somehow related to thermal hysteresis. Stress relief in the mounting structure can also produce significant hysteresis. As crystal processing techniques have improved. contamination has become less of a problem. PMID:18267585

  14. 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.

  15. 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.

  16. Bistability and hysteresis of annular impinging jets

    NASA Astrophysics Data System (ADS)

    Tisovsky, Tomas

    2016-06-01

    In present study, the bistability and hysteresis of annular impinging jets is investigated. Annular impinging jets are simulated using open source CFD code - OpenFOAM. Both flow field patterns of interest are obtained and hysteresis is found by means of dynamic mesh simulation. Effect of nozzle exit velocity on resulting hysteresis loop is also illustrated.

  17. Partitioning of potassium between silicates and sulphide melts: Experiements 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 investigaged 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. A mean K2S/FeS weight ratio of (3.340 + or - 0.015) x 0.001 was determined in these experiments; a K2S/FeS weight ratio of about 0.01 would be sufficient to extract all potassium in a chondritic earth into the core. Application of these 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.

  18. SILEX mission - First European experiment using optical frequencies between geostationary and low earth orbiting satellites

    NASA Astrophysics Data System (ADS)

    Faup, Michel; Laurent, Bernard; Pera, Luigi

    1991-10-01

    Since 1982, CNES has investigated the possibility to relay data from a low earth orbiting satellite to the ground via a geostationary satellite through a high data rate optical link. This work has led to a collaboration between ESA and CNES to implement the Semiconductor Intersatellite Link experiment (SILEX) which involves two terminals, one on Artemis (ESA geostationary satellite) and one on SPOT-4 (French Earth Observation Satellite). This paper presents the technical baseline that has been selected for SILEX. A short discussion of the performance will be initiated mainly concerning the questions linked to interfaces with the host platforms and the expected communication performance. The areas of development that could help to define the next generation of optical communication experiments and applications are explored.

  19. 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.

  20. 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.

  1. 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.

  2. Hysteresis and the Dynamic Elasticity of Consolidated Granular Materials

    NASA Astrophysics Data System (ADS)

    Guyer, R. A.; Tencate, James; Johnson, Paul

    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.

  3. Practical Experiences with Operational SOA infrastructure for Earth Observation: ECHO and Security

    NASA Astrophysics Data System (ADS)

    Burnett, M.

    2009-12-01

    The technical mechanisms for exchange of Earth Observation resources (data, services, clients, applications, etc.) are becoming mature. These mechanisms allow for new and innovative solutions to be assembled from components and services from a diverse group of sources. Standards, technologies and best practices are coalescing, allowing the Earth Observation community to more fully leverage web services, and the principles of a Service Oriented Architecture. NASA’s ECHO program provides a Service Oriented Architecture infrastructure. Through ECHO, users can discover and access over 110 million Earth Observation resources provided by NASA. ECHO has been operational for six years and the ECHO program has many practical experiences in fielding and operating SOA infrastructure for mission critical systems. This presentation will address the real impacts of providing operational SOA infrastructure for the Earth Observing community. There are significant impacts in the areas of performance, robustness, evolvability and usability. Of all of these important operational concerns, we will focus on the identification and mitigation of security risks in an operational SOA infrastructure environment.

  4. 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.

  5. 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.

  6. 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.

  7. The midcourse space experiment (MSX): Selected MWIR terrestrial and earth limb background measurements

    NASA Astrophysics Data System (ADS)

    O'Neil, Robert R.; Gardiner, Harold A. B.; Gibson, James J.

    1999-01-01

    The characterization of infrared terrestrial and earth limb backgrounds was a primary objective of MSX (the Midcourse Space Experiment), a BMDO (Ballistic Missile Defense Organization) program to support the requirements for the design and operation of proposed and conceptual infrared surveillance systems. The cryogenic phase of the MSX mission, April 24, 1996 to February 25, 1997, has provided definitive and unique measurements of infrared terrestrial and earth limb backgrounds. The mission provided precise radiometric measures at high spatial resolution in two MWIR (mid wavelength infrared) and four LWIR (long wavelength infrared) bands and characterized the mean radiance and spatial structure in 233 data collection events, nominally 20 to 30 minutes in duration, representing a wide range of terrestrial and limb phenomena. In this paper we present several examples of terrestrial and limb backgrounds for the two MWIR bands with full width half maximum band widths of 4.22-4.36 and 4.24-4.45 μm.

  8. 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.

  9. 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.

  10. 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.

  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. Asymmetric-hysteresis compensation in piezoelectric actuators

    NASA Astrophysics Data System (ADS)

    Aguirre, Gorka; Janssens, Thierry; Van Brussel, Hendrik; Al-Bender, Farid

    2012-07-01

    The advantages of using piezoelectric actuators in ultra-precision applications are often impaired by nonlinear effects, in particular hysteresis, which may lead to positioning uncertainties of up to 15% of the actuator's stroke. Model-based compensation strategies are often prescribed in order to overcome this limitation and achieve better dynamical accuracy. This comes, however, at the expense of increasing identification and implementation complexity, especially when hysteresis is of the asymmetric type, such as prevalent in hard piezoceramic materials. This paper proposes a new compensation strategy based upon (i) treating hysteresis as being separate from other dynamical effects and (ii) formulating a new, simplified model to deal with asymmetric hysteresis, based on applying a linear operator to the conventional hysteresis models. After developing the theoretical background of the compensation strategy, the accuracy improvement due to the new hysteresis-compensation method is demonstrated experimentally.

  13. Space stability investigations of optical coatings by earth- and space-based experiments

    NASA Astrophysics Data System (ADS)

    Hacker, Erich; Weissbrodt, P.; Raupach, L.; Lauth, Hans; Kappel, H.; Wagner, S.; Schmitt, Dirk-Roger

    1994-09-01

    Optical components for space optics - especially coated optical elements which represent the external surfaces of optical space instrumentation - have to work under harsh operation conditions like thermal loads, irradiation by photons, electrons and protons, as well as in atomic oxygen environments at low earth orbits. Additionally they have to withstand other cross contamination coming from the spacecraft. Therefore, the stability against these influences is a decisive factor for the application performance of optical coatings in space-borne devices. Some very recent results, based on the Surface Effects Sample Monitor (SESAM) flight experiment carried out aboard the ORFEUS-Shuttle Pallet Satellite (SPAS), STS-51, Discovery, are presented here along with laboratory experiments in an UHV-surface analysis system. The topics include ground simulation of selective and complex particle bombardment of optical coating analyzed by XPS as well as the verification of these results by flight experiments in combination with optical measurements (transmission, scattering).

  14. A purely local experiment - Poynting and the mean density of the Earth

    NASA Astrophysics Data System (ADS)

    Falconer, Isobel

    1999-06-01

    These days John Henry Poynting is best known for his association with the Poynting vector, which describes the flow of energy in an electromagnetic field, and little is known of his life or work. Yet in the 1890s he caught the popular imagination as `the man who weighed the Earth'. His experiment, using a novel method with a common balance, was part of a heroic tradition, gained him Cambridge University's Adams Prize, and set new standards of precision. Yet in performing this experiment, Poynting seemed to step outside the traditions of late nineteenth century Cambridge University where he was educated, and it is probably significant that he was a Unitarian throughout his life. This paper examines Poynting's experiment and his interpretation of it in the context of the rest of his life and work.

  15. Hysteresis and Frequency Tunability of Gyrotrons

    NASA Astrophysics Data System (ADS)

    Dumbrajs, O.; Khutoryan, E. M.; Idehara, T.

    2016-06-01

    We present the first devoted theoretical and experimental study of the hysteresis phenomenon in relation to frequency tunability of gyrotrons. In addition, we generalize the theory describing electron tuning of frequency in gyrotrons developed earlier to arbitrary harmonics. It is found that theoretical magnetic and voltage hysteresis loops are about two times larger than experimental loops. In gyrotrons whose cavities have high quality factors, hysteresis allows one only little to broaden the frequency tunability range.

  16. Improved charge amplifier using hybrid hysteresis compensation

    NASA Astrophysics Data System (ADS)

    Amin-Shahidi, Darya; Trumper, David L.

    2013-08-01

    We present a novel charge amplifier, with a robust feedback circuit and a method for compensating piezoelectric actuator's hysteresis at low frequencies. The amplifier uses a modified feedback circuit which improves robustness to the addition of series load impedance such as in cabling. We also describe a hybrid hysteresis compensation method for enabling the charge amplifier to reduce hysteresis at low frequencies. Experimental results demonstrate the utility of the new amplifier design.

  17. Full simulation of the LUCID experiment in the Low Earth Orbit radiation environment

    NASA Astrophysics Data System (ADS)

    Whyntie, T.; Harrison, M. A.

    2015-03-01

    The Langton Ultimate Cosmic ray Intensity Detector (LUCID) experiment is a satellite-based device that uses five Timepix hybrid silicon pixel detectors to make measurements of the radiation environment at an altitude of approximately 630 km, i.e. in Low Earth Orbit (LEO) . The experiment launched aboard Surrey Satellite Technology Limited's (SSTL's) TechDemoSat-1 on Tuesday the 8th of July 2014. The Timepix detectors, developed by the Medipix2 Collaboration, are arranged to form the five sides of a cube enclosed by a 0.7 mm thick aluminium covering, and are operated in Time-over-Threshold (ToT) mode to allow the flux, energy and directionality of incident ionising radiation to be measured. To understand the expected detector performance with respect to these measurements, the LUCID experiment has been modelled using the Allpix software package, a generic simulation toolkit for silicon pixel detectors built upon the GEANT4 framework. The work presented here summarises studies completed using the GridPP Collaboration's computing grid infrastructure to perform the simulations, store the resultant datasets, and share that data with the LUCID Collaboration. The analysis of these datasets has given an indication of the expected performance in differing space radiation environments (for example, during passes of the polar regions or the South Atlantic Anomaly), and has allowed the LUCID Collaboration to prepare for when data is transmitted back to Earth in late 2014.

  18. Hysteresis in layered spring magnets.

    SciTech Connect

    Jiang, J. S.; Kaper, H. G.; Leaf, G. K.; Mathematics and Computer Science

    2001-01-01

    This article addresses a problem of micromagnetics: the reversal of magnetic moments in layered spring magnets. A one-dimensional model is used of a film consisting of several atomic layers of a soft material on top of several atomic layers of a hard material. Each atomic layer is taken to be uniformly magnetized, and spatial inhomogeneities within an atomic layer are neglected. The state of such a system is described by a chain of magnetic spin vectors. Each spin vector behaves like a spinning top driven locally by the effective magnetic field and subject to damping (Landau-Lifshitz-Gilbert equation). A numerical integration scheme for the LLG equation is presented that is unconditionally stable and preserves the magnitude of the magnetization vector at all times. The results of numerical investigations for a bilayer in a rotating in-plane magnetic field show hysteresis with a basic period of 2{pi} at moderate fields and hysteresis with a basic period of {pi} at strong fields.

  19. Core hysteresis in nematic defects

    NASA Astrophysics Data System (ADS)

    Kralj, Samo; Virga, Epifanio G.

    2002-08-01

    We study field-induced transformations in the biaxial core of a nematic disclination with strength m=1, employing the Landau-de Gennes order tensor parameter Q. We first consider the transition from the defectless escaped radial structure into the structure hosting a line defect with a negative uniaxial order parameter along the axis of a cylinder of radius R. The critical field of the transition monotonically increases with R and asymptotically approaches a value corresponding to ξb/ξf~0.3, where the correlation lengths ξb and ξf are related to the biaxial order and the external field, respectively. Then, in the same geometry, we focus on the line defect structure with a positive uniaxial ordering along the axis, surrounded by the uniaxial sheath, the uniaxial cylinder of radius ξu with negative order parameter and director in the transverse direction. We study the hysteresis in the position of the uniaxial sheath upon increasing and decreasing the field strength. In general, two qualitatively different solutions exist, corresponding to the uniaxial sheath located close to the defect symmetry axis or close to the cylinder wall. This latter solution exists only for strong enough anchorings. The uniaxial sheath is for a line defect what the uniaxial ring is for a point defect: by resorting to an approximate analytic estimate, we show that essentially the same hysteresis exhibited by the uniaxial sheath is expected to occur at the uniaxial ring in the core structure of a point defect.

  20. 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

  1. 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.

  2. 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.

  3. 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.

  4. 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

  5. Hysteresis multicycles in nanomagnet arrays.

    PubMed

    Deutsch, J M; Mai, Trieu; Narayan, Onuttom

    2005-02-01

    We predict two physical effects in arrays of single-domain nanomagnets by performing simulations using a realistic model Hamiltonian and physical parameters. First, we find hysteretic multicycles for such nanomagnets. The simulation uses continuous spin dynamics through the Landau-Lifshitz-Gilbert (LLG) equation. In some regions of parameter space, the probability of finding a multicycle is as high as approximately 0.6 . We find that systems with larger and more anisotropic nanomagnets tend to display more multicycles. Our results also demonstrate the importance of disorder and frustration for multicycle behavior. Second, we show that there is a fundamental difference between the more realistic vector LLG equation and scalar models of hysteresis, such as Ising models. In the latter case spin and external field inversion symmetry is obeyed, but in the former it is destroyed by the dynamics, with important experimental implications. PMID:15783391

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

    DOE PAGESBeta

    Xu, Jixian; Buin, Andrei; Ip, Alexander H.; Li, Wei; Voznyy, Oleksandr; Comin, Riccardo; Yuan, Mingjian; Jeon, Seokmin; Ning, Zhijun; McDowell, Jeffrey; et al

    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

  7. 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

  8. 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.

  9. 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.

  10. 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.

  11. 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. PMID:25554309

  12. 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.

  13. Composition of the earth's atmosphere by shock-layer radiometry during the PAET entry probe experiment.

    NASA Technical Reports Server (NTRS)

    Whiting, E. E.; Arnold, J. O.; Page, W. A.; Reynolds, R. M.

    1973-01-01

    A determination of the composition of the earth's atmosphere obtained from onboard radiometer measurements of the spectra emitted from the bow shock layer of a high-speed entry probe is reported. The N2, O2, CO2, and noble gas concentrations in the earth's atmosphere were determined to good accuracy by this technique. The results demonstrate unequivocally the feasibility of determining the composition of an unknown planetary atmosphere by means of a multichannel radiometer viewing optical emission from the heated atmospheric gases in the region between the bow shock wave and the vehicle surface. The spectral locations in this experiment were preselected to enable the observation of CN violet, N2(+) first negative and atomic oxygen emission at 3870, 3910, and 7775 A, respectively. The atmospheric gases were heated and compressed by the shock wave to a peak temperature of about 6100 K and a corresponding pressure of 0.4 atm. Complete descriptions of the data analysis technique and the onboard radiometer and its calibration are given.

  14. 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.

  15. Fluid dynamics experiments on impact-induced metal dispersion during Earth's accretion

    NASA Astrophysics Data System (ADS)

    Deguen, R.; Risso, F.; Landeau, M.; Olson, P.

    2015-12-01

    Much of the Earth was built by high-energy impacts of planetesimals and embryos, many of these impactors already differentiated, with metallic cores of their own. Geochemical data provide critical information on the timing of accretion and the prevailing physical conditions, but their interpretation depends critically on the degree of metal-silicate chemical equilibration and metal dispersion during core-mantle differentiation, which is poorly constrained. Efficient equilibration requires that the large volumes of iron derived from impactor cores mix with molten silicates down to scales small enough to allow fast metal-silicate mass transfer. Here we use fluid dynamics experiments to investigate the fate of the metal phase of a planetesimal or planetary embryo colliding with the proto-Earth. The degree of metal-dispersion and metal-silicate mixing are found to depend primarily on the Froude number of the impactor, with "small" impacts (having large Froude numbers) having a comparatively higher amount of dispersion and mixing than "large" impacts (moderate Froude numbers).

  16. 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.

  17. 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

  18. 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.

  19. Measurements of the RF characteristics of earth lightning with the Galileo probe lightning experiment

    NASA Technical Reports Server (NTRS)

    Rinnert, K.; Lanzerotti, L. J.; Dehmel, G.; Gliem, F. O.; Krider, E. P.; Uman, M. A.

    1985-01-01

    The results of some measurements of earth lightning made with the functional unit of the Galileo probe RF lightning experiment are presented. The frequency range used is about 100 Hz to 100 kHz. The measurements were carried out in conjunction with simultaneous studies of lightning sources made by the University of Florida lightning research group. It is found that the typical RF pulse duration times are less than 30 microsec, independent of lightning source distance (less than 250 km). It is also found that the time between successive pulses is either quite short (less than 64 microsec), corresponding to the time between intracloud pulses and to the time between bipolar pulses, or occur around 100 ms, corresponding to the time between return strokes in ground discharges. The RF spectra are found to become less steep (relatively more power at the higher frequencies) during an interval of intense, nearby (less than 150 km) storms.

  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. 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.

  3. 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.

  4. 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.

  5. Stress hysteresis as the cause of persistent holes in particulate suspensions

    NASA Astrophysics Data System (ADS)

    Deegan, Robert D.

    2010-03-01

    Concentrated particulate suspensions under vibrations can support stable, localized, vertically oriented free surfaces. The most robust of these structures are persistent holes: deep and stable depressions of the interface. Using a reduced model of the hydrodynamics we show that a rheology with hysteresis can lead to motion opposite to the time-averaged applied force. Moreover, we show experimentally that particulate suspensions of cornstarch in water exhibits hysteresis in the shear-rate response to an applied sinusoidal stress. The results of our model and our experiments suggest that hysteresis accounts for the outward force needed to support persistent holes.

  6. 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

  7. 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.

  8. Estimating uncertainty caused by ocean heat transport to the North Sea: experiments downscaling EC-Earth

    NASA Astrophysics Data System (ADS)

    Tian, T.; Su, J.; Boberg, F.; Yang, S.; Schmith, T.

    2016-01-01

    The heat content of the North Sea is determined by the surface heat flux and the ocean heat transport into the region. The uncertainty in the projected warming in the North Sea caused by ocean heat transport has rarely been quantified. The difference in the estimates using regional ocean models is known to arise from the poorly prescribed temperature boundary forcing, either provided by global models at coarse grid resolutions, or from anomaly correction (using difference of the simulation from observed climatology) without interannual variation. In this study, two marine downscaling experiments were performed using boundary temperature forcings prepared with the two above mentioned strategies: one interpolated from a global model simulation (MI: model incl. interannual variation), and the other from observed climatology with warming trends in the future ocean derived from the global model simulation (OT: observed climatol. plus trend). The comparative experiments allowed us to estimate the uncertainty caused by ocean heat transport to the North Sea. The global climate model EC-Earth CMIP5 simulations of historical and future scenarios were used to provide lateral boundary forcing for regional models. The OT boundary was found to affect deep water temperatures (below 50 m) in the North Sea because of reduced interannual variability. The difference of mean temperature changes by 2100 (MI - OT) was up to 0.5 °C near the bottom across 58°N. While the deep water temperature in the North Sea did not directly link to the large-scale atmospheric circulation, the Norwegian outflow was highly correlated with the NAO index and heat transport of the Atlantic inflow provided by EC-Earth. It was found that model uncertainty due to the choice of lateral boundary forcing could be significant in the interannual variation of thermal stratification in the northern North Sea in a long-term simulation.

  9. 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.

  10. 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.

  11. 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. PMID:20060981

  12. 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

    2013-01-01

    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

  13. 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

  14. Geomorphological experiments for understanding cross-scale complexity of earth surface processes

    NASA Astrophysics Data System (ADS)

    Seeger, Manuel

    2016-04-01

    The shape of the earth's surface is the result of a complex interaction of different processes at different spatial and temporal scales. The challenging problem is, that process observation is rarely possible due to this different scales. In addition, the resulting landform often does not match the scale of process observation. But it is indispensable for the development of concepts of formation of landforms to identify and understand the involved processes and their interaction. To develop models it is even necessary to quantify them and their relevant parameters. Experiments are able to bridge the constraints of process observation mentioned above: it is possible to observe and quantify individual processes as well as complex process combinations up to the development of geomorphological units. The contribution aims at showing, based on soil erosion research, the possibilities of experimental methods for contributing to th understanding of geomorphological processes. A special emphasis is put on the linkage of conceptual understanding of processes, their measurement and the following development of models. The development of experiments to quantify relevant parameters will be shown, as well as the steps undertaken to bring them into the field taking into account the resulting increase of uncertainty in system parameters and results. It will be shown that experiments are even so able to produce precise measurements on individual processes as well as of complex combinations of parameters and processes and to identify their influence on the overall geomorphological dynamics. Experiments are therefore a methodological package able to check complex soil erosion processes at different levels of conceptualization and to generate data for their quantification. And thus, also a methodological concept to take more into account and to further develop in geomorphological science.

  15. 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.

  16. 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.

  17. 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

  18. Adhesion hysteresis of silane coated microcantilevers

    SciTech Connect

    DE BOER,MAARTEN P.; KNAPP,JAMES A.; MICHALSKE,TERRY A.; SRINIVASAN,U.; MABOUDIAN,R.

    2000-04-17

    The authors have developed a new experimental approach for measuring hysteresis in the adhesion between micromachined surfaces. By accurately modeling the deformations in cantilever beams that are subject to combined interfacial adhesion and applied electrostatic forces, they determine adhesion energies for advancing and receding contacts. They draw on this new method to examine adhesion hysteresis for silane coated micromachined structures and found significant hysteresis for surfaces that were exposed to high relative humidity (RH) conditions. Atomic force microscopy studies of these surfaces showed spontaneous formation of agglomerates that they interpreted as silages that have irreversibly transformed from uniform surface layers at low RH to isolated vesicles at high RH. They used contact deformation models to show that the compliance of these vesicles could reasonably account for the adhesion hysteresis that develops at high RH as the surfaces are forced into contact by an externally applied load.

  19. Earth's Core Formation and Composition : New Constraints from Diamond Anvil Cell Experiments

    NASA Astrophysics Data System (ADS)

    Siebert, J.; Badro, J.; Antonangeli, D.; Ryerson, F. J.

    2011-12-01

    The pattern of siderophile (iron-loving) element abundance in the silicate portion of the Earth is a consequence of metal separation during core formation. Thermodynamic expressions used to constrain the metal-silicate partitioning behavior of siderophile elements are mainly established from large volume press experiments that do not cover the full range of potential P-T conditions for core-mantle equilibrium. The diamond anvil cell is the only static technique capable of achieving required P-T conditions but until now its capabilities to perform quantitative metal-silicate partitioning experiments at extreme conditions has been untapped. We use protocols that effectively link high P-T diamond anvil cell with analytical techniques such as focused ion beam device (FIB); NanoSIMS; electron microprobe; transmission electron microscopes; and in-situ synchrotron X-ray diffraction measurements allow us to obtain quantitative data on element partitioning at superliquidus conditions above 30 GPa and 3000 K. Here we present our advances in both experimental and analytical methods. We look at the partitioning of 6 siderophile elements (Ni, Co, Cr, V, Mn, and Nb) that have been extensively studied at lower P-T conditions and constrain the solubility of light elements (Si and O) at these extreme conditions. We then update expressions that describe the partitioning behavior of these elements to address the validity of proposed core formation models (i.e. single-stage core formation model and continuous core formation model).

  20. 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.

  1. 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

  2. Free boundaries in problems with hysteresis

    PubMed Central

    Apushkinskaya, D. E.; Uraltseva, N. N.

    2015-01-01

    Here, we present a survey concerning parabolic free boundary problems involving a discontinuous hysteresis operator. Such problems describe biological and chemical processes ‘with memory’ in which various substances interact according to hysteresis law. Our main objective is to discuss the structure of the free boundaries and the properties of the so-called ‘strong solutions’ belonging to the anisotropic Sobolev class with sufficiently large q. Several open problems in this direction are proposed as well. PMID:26261368

  3. 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.

  4. 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.

  5. 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

  6. 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.

  7. Hysteresis and transition in swirling nonpremixed flames

    SciTech Connect

    Tummers, M.J.; Huebner, A.W.; van Veen, E.H.; Hanjalic, K.; van der Meer, T.H.

    2009-02-15

    Strongly swirling nonpremixed flames are known to exhibit a hysteresis when transiting from an attached long, sooty, yellow flame to a short lifted blue flame, and vice versa. The upward transition (by increasing the air and fuel flow rates) corresponds to a vortex breakdown, i.e. an abrupt change from an attached swirling flame (unidirectional or with a weak bluff-body recirculation), to a lifted flame with a strong toroidal vortex occupying the bulk of the flame. Despite dramatic differences in their structures, mixing intensities and combustion performance, both flame types can be realised at identical flow rates, equivalence ratio and swirl intensity. We report here on comprehensive investigations of the two flame regimes at the same conditions in a well-controlled experiment in which the swirl was generated by the rotating outer pipe of the annular burner air passage. Fluid velocity measured with PIV (particle image velocimetry), the qualitative detection of reaction zones from OH PLIF (planar laser-induced fluorescence) and the temperature measured by CARS (coherent anti-Stokes Raman spectroscopy) revealed major differences in vortical structures, turbulence, mixing and reaction intensities in the two flames. We discuss the transition mechanism and arguments for the improved mixing, compact size and a broader stability range of the blue flame in comparison to the long yellow flame. (author)

  8. 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

  9. 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.

  10. 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.-

  11. 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.

  12. 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.

  13. 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.

  14. 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.)

  15. 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.

  16. 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"

  17. 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

  18. 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.

  19. 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

  20. 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

  1. 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.

  2. 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.

  3. Geometric hysteresis of alveolated ductal architecture.

    PubMed

    Kojic, M; Butler, J P; Vlastelica, I; Stojanovic, B; Rankovic, V; Tsuda, A

    2011-11-01

    Low Reynolds number airflow in the pulmonary acinus and aerosol particle kinetics therein are significantly conditioned by the nature of the tidal motion of alveolar duct geometry. At least two components of the ductal structure are known to exhibit stress-strain hysteresis: smooth muscle within the alveolar entrance rings, and surfactant at the air-tissue interface. We hypothesize that the geometric hysteresis of the alveolar duct is largely determined by the interaction of the amount of smooth muscle and connective tissue in ductal rings, septal tissue properties, and surface tension-surface area characteristics of surfactant. To test this hypothesis, we have extended the well-known structural model of the alveolar duct by Wilson and Bachofen (1982, "A Model for Mechanical Structure of the Alveolar Duct," J. Appl. Physiol. 52(4), pp. 1064-1070) by adding realistic elastic and hysteretic properties of (1) the alveolar entrance ring, (2) septal tissue, and (3) surfactant. With realistic values for tissue and surface properties, we conclude that: (1) there is a significant, and underappreciated, amount of geometric hysteresis in alveolar ductal architecture; and (2) the contribution of smooth muscle and surfactant to geometric hysteresis are of opposite senses, tending toward cancellation. Quantitatively, the geometric hysteresis found experimentally by Miki et al. (1993, "Geometric Hysteresis in Pulmonary Surface-to-Volume Ratio during Tidal Breathing," J. Appl. Physiol. 75(4), pp. 1630-1636) is consistent with little or no smooth muscle tone in anesthetized rabbits in control conditions, and with substantial smooth muscle activation following methacholine challenge. The observed local hysteretic boundary motion of the acinar duct would result in irreversible acinar flow fields, which might be important mechanistic contributors to aerosol mixing and deposition deep in the lung. PMID:22168737

  4. 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.

  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. 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.

  7. 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.

  8. Variability in the Earth Radiation Budget as Determined from the NIMBUS ERB Experiments

    NASA Astrophysics Data System (ADS)

    Ardanuy, Philip Edward

    Data taken by the Earth Radiation Budget (ERB) experiments on board the Nimbus-6 and Nimbus-7 satellites is examined. The goal is an understanding of the bounds of variability of the radiation budget components. This variability is examined on daily, monthly, and annual time scales. An in-flight characterization of the instrument is performed, and a set of calibration adjustments for the Nimbus-7 ERB are developed that enable interannual climate studies to be made. A technique for the transfer of this calibration to the Nimbus-6 ERB experiment is derived that enables the creation of a decadal joint ERB data set. For the first time, error bars for the data set are established. These show that the WFOV calibration is accurate to 7 W/m('2) regionally and 3 W/m('2) zonally. Based on a solar calibration transfer, the stability of this data is shown to be better than 1/2% over the entire period. The radiation budget component (albedo and longwave emission) responses to the 1982 eruptions of the El Chichon volcano are examined. Based on the observations, an understanding of the global distribution, evolution, and persistence of the resultant aerosol cloud is achieved. Specific results include evidence that, although the eruptions occurred in the spring of 1982, the maximum optical depths at the higher latitudes in the northern hemisphere were not reached until the winter of 1982-1983. Further evident is the fact that the majority of the aerosols are retained in the northern hemisphere, with the aerosol content of the two hemispheres (as measured by the signal enhancements) not reaching equilibrium until two years after the eruption. The evolution of the major 1982/1983 ENSO event is monitored for the first time by broad-band radiometers. Quasi -stationary, planetary-scale tropical and mid-latitude teleconnection patterns are shown to emerge as the event reaches its peak intensity. The onset, intensification, and withdrawal of drought over Indonesia, Australia, the Pacific

  9. 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

  10. 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.

  11. 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

    2015-01-01

    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. PMID:26615895

  12. 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

  13. 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.

  14. 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.

  15. Authentic Research Experiences for Pre- and In-service Teachers: UNH’s Transforming Earth System Science Education (TESSE) Program

    NASA Astrophysics Data System (ADS)

    Varner, R. K.; Graham, K.; Bryce, J. G.; Finkel, L.; Froburg, E.; Hale, S.; Johnson, J. E.; von Damm, K.

    2009-12-01

    The University of New Hampshire’s Transforming Earth System Science Education (TESSE) project is designed to enrich the education and professional development of in-service and pre-service teachers who currently teach or plan to teach Earth science curricula. A key TESSE program goal is to foster the development of middle and high school students’ Earth System Science (ESS) literacy by engaging teachers in authentic research experiences. As part of TESSE, pre-service teachers are engaged in a research immersion experience (RIE), during which they work alongside a faculty research mentor for an intensive eight week period. The chief goal of this component of the program is to provide these pre-service teachers with authentic research experiences that will sharpen their research skills by providing guidance in designing projects and in gathering and interpreting data. The RIE also includes weekly discussions on pedagogical approaches to research with students, providing a catalyst for taking these research experiences into the classroom. For in-service teachers we have developed a course: “Research Techniques in the Earth System Sciences for Teachers.” Teachers enroll in an intensive ten-day research experience during which they participate in a research cruise on the Great Bay Estuary and collect gas and water samples, measure parameters in the water column, and collect sediment cores in order to answer questions they have posed about the estuary environment. Onshore, teacher teams analyze the water and core samples for gas and trace metal content, grain size, and other sedimentological characteristics. The research experience culminates with a public poster presentation of each team's results. Throughout the experience, teachers are engaged in a variety of discussions about transferring what they have learned about doing research to their classrooms. The integration of authentic research is a key mechanism that the TESSE program uses to help teachers

  16. 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.

  17. 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.

  18. Station coordinates in the Standard Earth III system derived by using camera data from ISAGEX. [International Satellite Geodesy Experiment

    NASA Technical Reports Server (NTRS)

    Gaposchkin, E. M.; Latimer, J.; Mendes, G.

    1975-01-01

    Simultaneous and individual camera observations of Geos 1, Geos 2, Pageos, and Midas 4 obtained during the International Satellite Geodesy Experiment are used to determine station coordinates. The Smithsonian Astrophysical Observatory Standard Earth III system of coordinates is utilized to tie the geometrical network to a geocentric system and as a reference for calculating satellite orbits. The normal systems for geometrical and dynamical solutions are combined.

  19. 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…

  20. Design of hysteresis circuits using differential amplifiers

    NASA Technical Reports Server (NTRS)

    Cooke, W. A.

    1971-01-01

    Design equations for hysteresis circuit are based on the following assumptions: amplifier input impedance is larger than source impedance; amplifier output impedance is less than load impedance; and amplifier switches state when differential input voltage is approximately zero. Circuits are designed to any given specifications.

  1. 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.

  2. Flexible pivot mount eliminates friction and hysteresis

    NASA Technical Reports Server (NTRS)

    Highman, C. O.

    1970-01-01

    Flexible steel pivot mount, suspended by flat vertical beryllium copper springs, is capable of rotation, free of hysteresis and starting friction. Mount requires no lubrication, is made in varying sizes, and is driven with either dc torque motor or mechanical linkage.

  3. 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.

  4. 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.

  5. 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

  6. 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%. PMID:17268571

  7. Calculation of hysteresis losses for Terfenol-D ultrasonic transducer

    NASA Astrophysics Data System (ADS)

    Zeng, Jianbin; Zeng, Haiquan; Bai, Baodong; Yan, Ming

    2009-07-01

    Thermal is one of critical factors effecting the application of Terfenol-D ultrasonic magnetostrictive transducer. Hysteresis losses are the main source for heating the it. A new method of hysteresis losses calculation, which based on Jiles-Atherton hysteresis model and electro-magnetic field finite element analysis, is proposed in this paper. The hysteresis losses obtained by this method can be used as thermal sources in electro-thermal finite element analysis of Terfenol-D ultrasonic transducer.

  8. The skylab S191 spectrometer experiment: Analysis of data and their applications to the earth sciences

    NASA Technical Reports Server (NTRS)

    Wilmarth, V. R.; Rainey, D. A.; Johnson, W. R.

    1978-01-01

    The data in the visible and near-infrared portions of the spectrum as recorded by identical spectrometers on Skylab and on a helicopter are examined to establish the significance of spectral reflectances from the Earth surface as influenced by water vapor, atmospheric gases, and aerosols. Models of radiation transfer show good agreement of theoretical computations and observed measurements.

  9. Earth Applications Group in the EGEE Europan Project : First experiments and objectives

    NASA Astrophysics Data System (ADS)

    Petitdidier, M.; Fusco, L.; Nercessian, A.; Vilotte, J.

    2004-12-01

    The aim of the EGEE (Enabling Grids E-science in Europe) project, funded by the EC is to build on recent advances in Grid Technology and to develop a service grid infrastructure, built on the EU Research Network GEANT, available to scientific and industrial applications. The Earth Sciences group is concern in the deployment of selected applications on the EGEE production testbed. Today applications include Earth Observation, Climate, Hydrology, Solid Earth and applied Geophysics. Recent developments made in the domains of Earth Observation and Solid Earth geophysics will be presented. In Earth observation, the goal is to drive the satellite operational and research community to use the Grid to process, validate and exchange large sets of data. This objective has begun during the European DataGrid project. First results have been obtained for Ozone data processing and validation. Large numbers and large volume of files from different satellite instruments (Gome and Gomos) and ground measurements have be handled on the Grid. More than 70,000,000 of Ozone profiles have been produced and stored on the Grid by orbit. The data has been processed with complex algorithms (e.g. Neural approach, inversion methods) using IDL-runtime. Creation and secure access to metadata and satellite data has been made possible on the Grid. Moreover, ESA built a secure portal to access to its Archive Mass Storage to transfer satellite data on the Grid and to process the selected data. This Grid interface has provided a very progressive way for end-users to access and process satellite data. In EGEE an attempt to access other satellite archives from the Grid and process scientific jobs requiring access to several databases for quasi-real time prediction, like ozone, is in progress. In The Solid Earth, a first example of the use of the GRID has been done in the case of a seismic tomography study by IPG Paris. Secure and restricted access to database has been demonstrated as well as complex

  10. 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

  11. Analysis of wasp-waisted hysteresis loops in magnetic rocks.

    PubMed

    Kharwanlang, R S; Shukla, Prabodh

    2012-01-01

    The random-field Ising model of hysteresis is generalized to dilute magnets and is solved on a Bethe lattice. Exact expressions for the major and minor hysteresis loops are obtained. In the strongly dilute limit the model provides a simple and useful understanding of the shapes of hysteresis loops in magnetic rock samples. PMID:22400529

  12. 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.

  13. 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.

  14. Inelastic compaction, dilation and hysteresis of sandstones under hydrostatic conditions

    NASA Astrophysics Data System (ADS)

    Shalev, Eyal; Lyakhovsky, Vladimir; Ougier-Simonin, Audrey; Hamiel, Yariv; Zhu, Wenlu

    2014-05-01

    Sandstones display non-linear and inelastic behaviour such as hysteresis when subjected to cyclic loading. We present three hydrostatic compaction experiments with multiple loading-unloading cycles on Berea and Darley Dale sandstones and explain their hysteretic behaviour using non-linear inelastic compaction and dilation. Each experiment included eight to nine loading-unloading cycles with increasing maximum pressure in each subsequent cycle. Different pressure-volumetric strain relations during loading and unloading were observed. During the first cycles, under relatively low pressures, not all of the volumetric strain is recovered at the end of each cycle whereas at the last cycles, under relatively high pressures, the strain is recovered and the pressure-volumetric strain hysteresis loops are closed. The observed pressure-volumetric strain relations are non-linear and the effective bulk modulus of the sandstones changes between cycles. Observations are modelled with two inelastic deformation processes: irreversible compaction caused by changes in grain packing and recoverable compaction associated with grain contact adhesion, frictional sliding on grains or frictional sliding on cracks. The irreversible compaction is suggested to reflect rearrangement of grains into a more compact mode as the maximum pressure increases. Our model describes the `inelastic compaction envelope' in which sandstone sample will follow during hydrostatic loading. Irreversible compaction occurs when pressure is greater than a threshold value defined by the `inelastic compaction envelope'.

  15. 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

  16. 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

  17. Migration of a coarse fluvial sediment pulse detected by hysteresis in bedload generated seismic waves

    NASA Astrophysics Data System (ADS)

    Roth, D. L.; Finnegan, N. J.; Brodsky, E. E.; Cook, K. L.; Stark, C. P.; Wang, H. W.

    2014-10-01

    Seismic signals near rivers are partially composed of the elastic waves generated by bedload particles impacting the river bed. In this study, we explore the relationship between this seismic signal and river bedload transport by analyzing high-frequency broadband seismic data from multiple stations along the Chijiawan River in northern Taiwan following the removal of a 13 m check dam. This dam removal provides a natural experiment in which rapid and predictable changes in the river's profile occur, which in turn enables independent constraints on spatial and temporal variation in bedload sediment transport. We compare floods of similar magnitudes with and without bedload transport, and find that the amplitude of seismic shaking produced at a given river stage changes over the course of a single storm when bedload transport is active. Hysteresis in the relationship between bedload transport and river stage is a well-documented phenomenon with multiple known causes. Consequently, previous studies have suggested that hysteresis observed in the seismic amplitude-stage response is the signature of bedload transport. Field evidence and stream profile evolution in this study corroborate that interpretation. We develop a metric (Ψ) for the normalized magnitude of seismic hysteresis during individual floods. This metric appears to scale qualitatively with total bedload transport at each seismic station, indicating a dominance of transport on the rising limbs of both storms. We speculate that hysteresis at this site arises from time-dependent evolution of the bed, for example due to grain packing, mobile armoring, or the temporal lag between stage and bedform growth. Ψ reveals along-stream variations in hysteresis for each storm, with a peak in hysteresis further downstream for the second event. The pattern is consistent with a migrating sediment pulse that is a predicted consequence of the dam removal. Our results indicate that hysteresis in the relationship between

  18. Hysteresis phenomenon in the galloping oscillation of a square cylinder

    NASA Astrophysics Data System (ADS)

    Luo, S. C.; Chew, Y. T.; Ng, Y. T.

    2003-08-01

    It is well known that a square cylinder with one side normal to a uniform stream will gallop when a critical flow velocity is exceeded. It is also quite well known that there is a hysteresis phenomenon in the variation of the cylinder's galloping amplitude with the flow velocity. However, little is known about the cause of this hysteresis phenomenon, and the objective of this paper is to study it more closely. In the present study, flow over a stationary square cylinder at different angle of attack (/α) and at Reynolds number (Re) of 250 and 1000 was investigated numerically by using a 2-D hybrid vortex computation scheme. The study reveals that the well known point of inflection which exists in the side force (Cy) versus /α plots at high Reynolds number only occurs at Re=1000, /α=4° in the present numerical simulation. Nonlinear analysis further reveals that this point of inflection is the cause of the hysteresis phenomenon. By further analysing the computed flow field, it is noted that at Re=1000, /α=4°, intermittent flow reattachment takes place at alternate vortex shedding cycle on one side of the cylinder. This results in larger side force fluctuation, and it is conjectured that such large side force fluctuation affects the increasing trend of the side force with angle of attack, resulting in the point of inflection reported earlier. The above-mentioned alternate cycle flow reattachment was much less prominent at /α=2° and 6° (Re=1000), and was not observed at Re=250. Finally, dye flow visualization was carried out in a recirculating water tunnel and the results at Re=1000 confirms the existence of the intermittent flow reattachment. However, in the experiment, flow reattachment does not take place in a very regular alternate cycle manner as in the computation. Instead, it occurs intermittently, possibly due to three-dimensional effects in real flow.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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

  4. Vectorized Jiles-Atherton hysteresis model

    NASA Astrophysics Data System (ADS)

    Szymański, Grzegorz; Waszak, Michał

    2004-01-01

    This paper deals with vector hysteresis modeling. A vector model consisting of individual Jiles-Atherton components placed along principal axes is proposed. The cross-axis coupling ensures general vector model properties. Minor loops are obtained using scaling method. The model is intended for efficient finite element method computations defined in terms of magnetic vector potential. Numerical efficiency is ensured by differential susceptibility approach.

  5. Electromagnetic phenomena and hysteresis losses in superconductors

    NASA Astrophysics Data System (ADS)

    Matsushita, T.

    Hysteresis losses in superconductors are caused by irreversible motion of fluxoids. This motion is, in most cases, described by the critical state model. In this article, various electromagnetic phenomena due to flux pinning effects are reviewed and explanations of these phenomena are given using the critical state model. The phenomena which cannot be well described by the present model, such as reversible fluxoid motion and the longitudinal field effect, are also introduced.

  6. Electroosmotic flow hysteresis for dissimilar ionic solutions.

    PubMed

    Lim, An Eng; Lim, Chun Yee; Lam, Yee Cheong

    2015-03-01

    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

  7. 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

  8. 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. PMID:22680688

  9. A combined Preisach-Hyperbolic Tangent model for magnetic hysteresis of Terfenol-D

    NASA Astrophysics Data System (ADS)

    Talebian, Soheil; Hojjat, Yousef; Ghodsi, Mojtaba; Karafi, Mohammad Reza; Mirzamohammadi, Shahed

    2015-12-01

    This study presents a new model using the combination of Preisach and Hyperbolic Tangent models, to predict the magnetic hysteresis of Terfenol-D at different frequencies. Initially, a proper experimental setup was fabricated and used to obtain different magnetic hysteresis curves of Terfenol-D; such as major, minor and reversal loops. Then, it was shown that the Hyperbolic Tangent model is precisely capable of modeling the magnetic hysteresis of the Terfenol-D for both rate-independent and rate-dependent cases. Empirical equations were proposed with respect to magnetic field frequency which can calculate the non-dimensional coefficients needed by the model. These empirical equations were validated at new frequencies of 100 Hz and 300 Hz. Finally, the new model was developed through the combination of Preisach and Hyperbolic Tangent models. In the combined model, analytical relations of the Hyperbolic Tangent model for the first order reversal loops determined the weighting function of the Preisach model. This model reduces the required experiments and errors due to numerical differentiations generally needed for characterization of the Preisach function. In addition, it can predict the rate-dependent hysteresis as well as rate-independent hysteresis.

  10. Controller Parameter Tuning for Systems with Hysteresis and Its Application to Shape Memory Alloy Actuators

    NASA Astrophysics Data System (ADS)

    Wakasa, Yuji; Kanagawa, Shinji; Tanaka, Kanya; Nishimura, Yuki

    This paper proposes a simple controller parameter tuning method that can compensate for hysteresis. The proposed method is based on the so-called fictitious reference iterative tuning (FRIT) technique which can easily tune controller parameters such as proportional-integral-derivative gains using a one-shot closed-loop experimental data. In the proposed framework, a simple hysteresis model is introduced to a control system, and its inverse is used as a hysteresis compensator. Since the hysteresis model is characterized with only three parameters, the related computational burden is moderate in the parameter tuning process. Also, the proposed FRIT method needs an only one-shot experiment as in the standard FRIT one, which implies that the feature of FRIT is well-maintained. In the optimization process, the so-called covariance matrix adaptation evolution strategy is used for simultaneously searching hysteresis parameters as well as controller parameters. The proposed FRIT method is applied to an experimental control system that comprises a shape memory alloy actuator, and its effectiveness is verified.