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Sample records for failure corona incremental

  1. Corona-vacuum failure mechanism test facilities

    NASA Technical Reports Server (NTRS)

    Lalli, V. R.; Mueller, L. A.; Koutnik, E. A.

    1975-01-01

    A nondestructive corona-vacuum test facility for testing high-voltage power system components has been developed using commercially available hardware. The facility simulates operating temperature and vacuum while monitoring coronal discharges with residual gases. Corona threshold voltages obtained from statorette tests with various gas-solid dielectric systems and comparison with calculated data support the following conclusions: (1) air gives the highest corona threshold voltage and helium the lowest, with argon and helium-xenon mixtures intermediate; (2) corona threshold voltage increases with gas pressure; (3) corona threshold voltage for an armature winding can be accurately calculated by using Paschen curves for a uniform field; and (4) Paschen curves for argon can be used to calculate the corona threshold voltage in He-Xe mixtures, for which Paschen curves are unavailable.-

  2. A Comparative Study of Failure with Incremental Forming

    NASA Astrophysics Data System (ADS)

    Wu, S. H.; Song, N. N.; Pires, F. M. Andrade

    2016-08-01

    Incremental forming (ISF) is an innovative flexible sheet metal forming process which can be used to manufacture complex shapes from various materials. Due to its flexibility, it has attracted more and more attention over recent decades. Localized deformation and shear through the thickness are essential characteristics of ISF. These lead to specific failure modes and formability of ISF that are different from the conventional stamping process. In this contribution, three continuum damage models (Lemaitre, Gurson, extended GTN models) are formulated and fully coupled with the finite element simulation in a commercial software ABAQUS to predict failure in incremental forming. A comparative investigation of these three damage models has been carried out to analyze both the deformation behavior and failure mechanisms.

  3. Incrementalism, Majoritarianism, and the Failures of School Desegregation.

    ERIC Educational Resources Information Center

    Hochschild, Jennifer L.

    This paper argues that cautious and participatory desegregation efforts yield less desirable outcomes than either sweeping, authoritative desegregation policies or no imposed effort at all. The author proceeds to support these claims by identifying 10 goals of school desegregation and examining the rules and consequences of incremental and…

  4. Risk stratification of patients with chronic heart failure using cardiac iodine‐123 metaiodobenzylguanidine imaging: incremental prognostic value over right ventricular ejection fraction

    PubMed Central

    Yamada, Takahisa; Morita, Takashi; Furukawa, Yoshio; Iwasaki, Yusuke; Kawasaki, Masato; Kikuchi, Atsushi; Kondo, Takumi; Kawai, Tsutomu; Takahashi, Satoshi; Ishimi, Masashi; Hakui, Hideyuki; Ozaki, Tatsuhisa; Sato, Yoshihiro; Seo, Masahiro; Sakata, Yasushi; Fukunami, Masatake

    2015-01-01

    Abstract Aims Right ventricular (RV) systolic dysfunction has been shown to be an independent predictor of clinical outcome in patients with chronic heart failure (CHF), and cardiac metaiodobenzylguanidine (MIBG) imaging also provides prognostic information. We aimed to evaluate the long‐term predictive value of combining RV systolic dysfunction and abnormal findings of cardiac MIBG imaging on outcome in CHF patients. Methods and results We enrolled 63 CHF outpatients with left ventricular ejection fraction (EF) <40% in a prospective cohort study. At entry, RVEF was measured by radionuclide angiography. Furthermore, cardiac MIBG imaging was performed, and the cardiac MIBG washout rate (WR) was calculated. Reduced RVEF was defined as ≤37%, and abnormal WR was defined as >27%. The study endpoint was unplanned hospitalization for worsening heart failure (WHF) and cardiac death. During a follow‐up period of 8.9 ± 4.3 years, 19 of 63 patients had unplanned hospitalization for WHF, and 19 of 63 patients had cardiac death. In multivariate analysis, both WR and RVEF were independent predictors of unplanned WHF hospitalization, while WR was also an independent predictor of cardiac death. A risk‐stratification model based on independent predictors of unplanned WHF hospitalization separated the patients into those with low (absence of the predictors), intermediate (one of the predictors), and high (two or more of the predictors) risk of unplanned WHF hospitalization (P < 0.0001) or cardiac death (P = 0.0113). Conclusions Cardiac MIBG imaging provides incremental value when it is used along with RV systolic dysfunction to predict clinical outcome in patients with CHF.

  5. Corona Borealis

    NASA Astrophysics Data System (ADS)

    Murdin, P.

    2000-11-01

    (the Northern Crown; abbrev. CrB, gen. Coronae Borealis; area 179 sq. deg.) A northern constellation which lies between Boötes and Hercules, and culminates at midnight in mid-May. It represents the crown that in Greek mythology was made by Hephaestus, god of fire, and worn by Princess Ariadne of Crete. Its brightest stars were cataloged by Ptolemy (c. AD 100-175) in the Almagest....

  6. Incremental haemodialysis.

    PubMed

    Wong, Jonathan; Vilar, Enric; Davenport, Andrew; Farrington, Ken

    2015-10-01

    Thrice-weekly haemodialysis schedules have become the standard default haemodialysis prescription worldwide. Whereas the measurement of residual renal function is accepted practice for peritoneal dialysis patients and the importance of residual renal function in determining technique success is well established, few centres routinely assess residual renal function in haemodialysis patients. Although intradialytic hypotension and episodes of acute kidney injury may predispose to an earlier loss of residual renal function, a significant proportion of haemodialysis patients maintain some residual function long after dialysis initiation. As such, an incremental approach to the initiation of dialysis with careful monitoring of residual renal function may potentially provide some haemodialysis patients with an improved quality of life and greater preservation of residual renal function whilst fewer dialysis sessions may reduce health care costs. Prospective trials are required to determine the optimum approach to the initiation of haemodialysis for the oliguric patient. Once residual renal function has been lost, then dialysis prescriptions should be re-examined to consider the use of longer or more frequent treatment sessions and switching from low-flux to high-flux dialysis or haemodiafiltration to offset retention of middle sized molecules and protein-bound azotaemic solutes.

  7. Ultrasonic corona sensor study

    NASA Technical Reports Server (NTRS)

    Harrold, R. T.

    1976-01-01

    The overall objective of this program is to determine the feasibility of using ultrasonic (above 20 kHz) corona detection techniques to detect low order (non-arcing) coronas in varying degrees of vacuum within large high vacuum test chambers, and to design, fabricate, and deliver a prototype ultrasonic corona sensor.

  8. Simulating coronas in color.

    PubMed

    Gedzelman, Stanley D; Lock, James A

    2003-01-20

    Coronas are simulated in color by use of the Mie scattering theory of light by small droplets through clouds of finite optical thickness embedded in a Rayleigh scattering atmosphere. The primary factors that affect color, visibility, and number of rings of coronas are droplet size, width of the size distribution, and cloud optical thickness. The color sequence of coronas and iridescence varies when the droplet radius is smaller than approximately 6-microm. As radius increases to approximately 3.5 microm, new color bands appear at the center of the corona and fade as they move outward. As the radius continues to increase to approximately 6 microm, successively more inner rings become fixed in the manner described by classical diffraction theory, while outer rings continue their outward migration. Wave clouds or rippled cloud segments produce the brightest and most vivid multiple ringed coronas and iridescence because their integrated dropsize distributions along sunbeams are much narrower than in convective or stratiform clouds. The visibility of coronas and the appearance of the background sky vary with cloud optical depth tau. First the corona becomes visible as a white aureole in a blue sky when tau approximately 0.001. Color purity then rapidly increases to an almost flat maximum in the range 0.05 < or = tau < or = 0.5 and then decreases, so coronas are almost completely washed out by a bright gray background when tau > or = 4.

  9. Characteristics of a corona discharge with a hot corona electrode

    SciTech Connect

    Kulumbaev, E. B.; Lelevkin, V. M.; Niyazaliev, I. A.; Tokarev, A. V.

    2011-08-15

    The effect of the temperature of the corona electrode on the electrical characteristics of a corona discharge was studied experimentally. A modified Townsend formula for the current-voltage characteristic of a one-dimensional corona is proposed. Gasdynamic and thermal characteristics of a positive corona discharge in a coaxial electrode system are calculated. The calculated results are compared with the experimental data.

  10. Disease specific protein corona

    NASA Astrophysics Data System (ADS)

    Rahman, M.; Mahmoudi, M.

    2015-03-01

    It is now well accepted that upon their entrance into the biological environments, the surface of nanomaterials would be covered by various biomacromolecules (e.g., proteins and lipids). The absorption of these biomolecules, so called `protein corona', onto the surface of (nano)biomaterials confers them a new `biological identity'. Although the formation of protein coronas on the surface of nanoparticles has been widely investigated, there are few reports on the effect of various diseases on the biological identity of nanoparticles. As the type of diseases may tremendously changes the composition of the protein source (e.g., human plasma/serum), one can expect that amount and composition of associated proteins in the corona composition may be varied, in disease type manner. Here, we show that corona coated silica and polystyrene nanoparticles (after interaction with in the plasma of the healthy individuals) could induce unfolding of fibrinogen, which promotes release of the inflammatory cytokines. However, no considerable releases of inflammatory cytokines were observed for corona coated graphene sheets. In contrast, the obtained corona coated silica and polystyrene nanoparticles from the hypofibrinogenemia patients could not induce inflammatory cytokine release where graphene sheets do. Therefore, one can expect that disease-specific protein coronas can provide a novel approach for applying nanomedicine to personalized medicine, improving diagnosis and treatment of different diseases tailored to the specific conditions and circumstances.

  11. Corona and solar wind

    NASA Astrophysics Data System (ADS)

    Withbroe, G. L.

    1986-04-01

    The Pinhole/Occulter Facility is a powerful tool for studying the physics of the extended corona and origins of the solar wind. Spectroscopic data acquired by the P/OF coronal instruments can greatly expand empirical information about temperatures, densities, flow velocities, magnetic fields, and chemical abundances in the corona out to r or approx. 10 solar radii. Such information is needed to provide tight empirical constraints on critical physical processes involved in the transport and dissipation of energy and momentum, the heating and acceleration of plasma, and the acceleration of energetic particles. Because of its high sensitivity, high spatial and temporal resolutions, and powerful capabilities for plasma diagnostics, P/OF can significantly increase our empirical knowledge about coronal streamers and transients and thereby advance the understanding of the physics of these phenomena. P/OF observations can be used to establish the role in solar wind generation, if any, of small-scale dynamical phenomena, such as spicules, macrospicules and coronal bullets, and the role of the fine-scale structures, such as polar plumes. Finally, simultaneous measurements by the P/OF coronal and hard X-ray instruments can provide critical empirical information concerning nonthermal energy releases and acceleration of energetic particles in the corona.

  12. Corona and solar wind

    NASA Technical Reports Server (NTRS)

    Withbroe, G. L.

    1986-01-01

    The Pinhole/Occulter Facility is a powerful tool for studying the physics of the extended corona and origins of the solar wind. Spectroscopic data acquired by the P/OF coronal instruments can greatly expand empirical information about temperatures, densities, flow velocities, magnetic fields, and chemical abundances in the corona out to r or approx. 10 solar radii. Such information is needed to provide tight empirical constraints on critical physical processes involved in the transport and dissipation of energy and momentum, the heating and acceleration of plasma, and the acceleration of energetic particles. Because of its high sensitivity, high spatial and temporal resolutions, and powerful capabilities for plasma diagnostics, P/OF can significantly increase our empirical knowledge about coronal streamers and transients and thereby advance the understanding of the physics of these phenomena. P/OF observations can be used to establish the role in solar wind generation, if any, of small-scale dynamical phenomena, such as spicules, macrospicules and coronal bullets, and the role of the fine-scale structures, such as polar plumes. Finally, simultaneous measurements by the P/OF coronal and hard X-ray instruments can provide critical empirical information concerning nonthermal energy releases and acceleration of energetic particles in the corona.

  13. Coronae on stars

    NASA Technical Reports Server (NTRS)

    Haisch, B. M.

    1986-01-01

    Three lines of evidence are noted to point to a flare heating source for stellar coronae: a strong correlation between time-averaged flare energy release and coronal X-ray luminosity, the high temperature flare-like component of the spectral signature of coronal X-ray emission, and the observed short time scale variability that indicates continuous flare activity. It is presently suggested that flares may represent only the extreme high energy tail of a continuous distribution of coronal energy release events.

  14. Accretion disk coronae

    NASA Technical Reports Server (NTRS)

    White, N. E.; Holt, S. S.

    1981-01-01

    Recent observations of partial X-ray eclipses from 4U1822-37 have shown that the central X-ray source in this system is diffused by a large Compton-thick accretion disk corona (ADC). Another binary, 4U2129-47, also displays a partial eclipse and contains an ADC. The possible origin of an ADC is discussed and a simple hydrostatic evaporated ADC model is developed which, when applied to 4U1822-37, 4U2129+47 and Cyg X-3, can explain their temporal and spectral properties. The quasi-sinusoidal modulation of all three sources can be reconciled with the partial occultation of the ADC by a bulge at the edge of the accretion disk which is caused by the inflowing material. The height of this bulge is an order of magnitude larger than the hydrostatic disk height and is the result of turbulence in the outer region of the disk. The spectral properties of all three sources can be understood in terms of Compton scattering of the original source spectrum by the ADC. Spectral variations with epoch in Cyg X-3 are probably caused by changes in the optical depth of the corona. A consequence of our model is that any accreting neutron star X-ray source in a semi-detached binary system which is close to its Eddington limit most likely contains an optically thick ADC.

  15. Incremental Contingency Planning

    NASA Technical Reports Server (NTRS)

    Dearden, Richard; Meuleau, Nicolas; Ramakrishnan, Sailesh; Smith, David E.; Washington, Rich

    2003-01-01

    There has been considerable work in AI on planning under uncertainty. However, this work generally assumes an extremely simple model of action that does not consider continuous time and resources. These assumptions are not reasonable for a Mars rover, which must cope with uncertainty about the duration of tasks, the energy required, the data storage necessary, and its current position and orientation. In this paper, we outline an approach to generating contingency plans when the sources of uncertainty involve continuous quantities such as time and resources. The approach involves first constructing a "seed" plan, and then incrementally adding contingent branches to this plan in order to improve utility. The challenge is to figure out the best places to insert contingency branches. This requires an estimate of how much utility could be gained by building a contingent branch at any given place in the seed plan. Computing this utility exactly is intractable, but we outline an approximation method that back propagates utility distributions through a graph structure similar to that of a plan graph.

  16. Directed Incremental Symbolic Execution

    NASA Technical Reports Server (NTRS)

    Person, Suzette; Yang, Guowei; Rungta, Neha; Khurshid, Sarfraz

    2011-01-01

    The last few years have seen a resurgence of interest in the use of symbolic execution -- a program analysis technique developed more than three decades ago to analyze program execution paths. Scaling symbolic execution and other path-sensitive analysis techniques to large systems remains challenging despite recent algorithmic and technological advances. An alternative to solving the problem of scalability is to reduce the scope of the analysis. One approach that is widely studied in the context of regression analysis is to analyze the differences between two related program versions. While such an approach is intuitive in theory, finding efficient and precise ways to identify program differences, and characterize their effects on how the program executes has proved challenging in practice. In this paper, we present Directed Incremental Symbolic Execution (DiSE), a novel technique for detecting and characterizing the effects of program changes. The novelty of DiSE is to combine the efficiencies of static analysis techniques to compute program difference information with the precision of symbolic execution to explore program execution paths and generate path conditions affected by the differences. DiSE is a complementary technique to other reduction or bounding techniques developed to improve symbolic execution. Furthermore, DiSE does not require analysis results to be carried forward as the software evolves -- only the source code for two related program versions is required. A case-study of our implementation of DiSE illustrates its effectiveness at detecting and characterizing the effects of program changes.

  17. Ultraviolet corona detection sensor study

    NASA Technical Reports Server (NTRS)

    Schmitt, R. J.; MATHERN

    1976-01-01

    The feasibility of detecting electrical corona discharge phenomena in a space simulation chamber via emission of ultraviolet light was evaluated. A corona simulator, with a hemispherically capped point to plane electrode geometry, was used to generate corona glows over a wide range of pressure, voltage, current, electrode gap length and electrode point radius. Several ultraviolet detectors, including a copper cathode gas discharge tube and a UV enhanced silicon photodiode detector, were evaluated in the course of the spectral intensity measurements. The performance of both silicon target vidicons and silicon intensified target vidicons was evaluated analytically using the data generated by the spectroradiometer scans and the performance data supplied by the manufacturers.

  18. Parallel incremental compilation. Doctoral thesis

    SciTech Connect

    Gafter, N.M.

    1990-06-01

    The time it takes to compile a large program has been a bottleneck in the software development process. When an interactive programming environment with an incremental compiler is used, compilation speed becomes even more important, but existing incremental compilers are very slow for some types of program changes. We describe a set of techniques that enable incremental compilation to exploit fine-grained concurrency in a shared-memory multi-processor and achieve asymptotic improvement over sequential algorithms. Because parallel non-incremental compilation is a special case of parallel incremental compilation, the design of a parallel compiler is a corollary of our result. Instead of running the individual phases concurrently, our design specifies compiler phases that are mutually sequential. However, each phase is designed to exploit fine-grained parallelism. By allowing each phase to present its output as a complete structure rather than as a stream of data, we can apply techniques such as parallel prefix and parallel divide-and-conquer, and we can construct applicative data structures to achieve sublinear execution time. Parallel algorithms for each phase of a compiler are presented to demonstrate that a complete incremental compiler can achieve execution time that is asymptotically less than sequential algorithms.

  19. Rainbows, Coronas and Glories

    NASA Astrophysics Data System (ADS)

    Laven, Philip

    Rainbows, coronas and glories are examples of atmospheric optical phenomena caused by the scattering of sunlight from spherical drops of water. It is surprising that the apparently simple process of scattering of light by spherical drops of water can result in this wide range of colourful effects. However, the scattering mechanisms are very complicated. Eminent scientists (such as Descartes, Newton, Young, Airy and many others) offered various explanations for the formation of rainbows—thus making major contributions to our understanding of the nature of light. The basic features of rainbows can be explained by geometrical optics but, in the early 1800s, supernumerary arcs on rainbows provided crucial supporting evidence for the wave theory of light. In 1908, Mie provided a rigorous (but very complicated) solution to the problem of scattering of light by spherical particles. More than 100 years later, Mie's solution can now be used to produce excellent full-colour simulations. Examples of such simulations show how the appearance of these phenomena vary with the size of the water drops, as well as describing the scattering mechanisms that are responsible for their formation.

  20. Experimental Study of Magnetic Field Effect on dc Corona Discharge in Low Vacuum

    NASA Astrophysics Data System (ADS)

    Elabbas, K.

    2014-09-01

    In the present paper, an attempt was made to investigate the effect of applying a transverse magnetic field on the dc corona discharge behavior in low vacuum. In general, two experiments were carried out in this work: the first is the ionization-region magnetic field experiment, and the second was the drift region magnetic field experiment. In these experiments, permanent magnets were used to produce magnetic field. The degree of vacuum used in this test was 0.4×105 Pa. It is found that the effect of the magnetic field increases as the degree of vacuum increases. It is also seen from this study that the corona current values are higher with magnetic fields than without magnetic fields. The experimental results indicate that the enhancement of the magnetic field near the wire discharge electrode has a significant influence on the increment of the discharge current. The effect of the magnetic field on the discharge current is the most significant with the negative corona discharges rather than with positive corona discharge. In contrast to, the curves were demonstrated that the application of magnetic fields in drift region magnetic field does not significantly change the corona discharge current. Discharge characteristics of magnetically enhanced corona discharges, extracted from this study, can be applied to various industrial applications, such as, in an electrostatic enhancement filter for the purpose of capturing fine particles, and as effective method for production of high ozone concentrations in a generator as compared to the ultraviolet (UV) radiation method.

  1. Insights into Corona Formation Through Statistical Analyses

    NASA Technical Reports Server (NTRS)

    Glaze, L. S.; Stofan, E. R.; Smrekar, S. E.; Baloga, S. M.

    2002-01-01

    Statistical analysis of an expanded database of coronae on Venus indicates that the populations of Type 1 (with fracture annuli) and 2 (without fracture annuli) corona diameters are statistically indistinguishable, and therefore we have no basis for assuming different formation mechanisms. Analysis of the topography and diameters of coronae shows that coronae that are depressions, rimmed depressions, and domes tend to be significantly smaller than those that are plateaus, rimmed plateaus, or domes with surrounding rims. This is consistent with the model of Smrekar and Stofan and inconsistent with predictions of the spreading drop model of Koch and Munga. The diameter range for domes, the initial stage of corona formation, provides a broad constraint on the buoyancy of corona-forming plumes. Coronae are only slightly more likely to be topographically raised than depressions, with Type 1 coronae most frequently occurring as rimmed depressions and Type 2 coronae most frequently occurring with flat interiors and raised rims. Most Type 1 coronae are located along chasmata systems or fracture belts, while Type 2 coronae are found predominantly as isolated features in the plains. Coronae at hot spot rises tend to be significantly lager than coronae in other settings, consistent with a hotter upper mantle at hot spot rises and their active state.

  2. Insights into Corona Formation through Statistical Analyses

    NASA Technical Reports Server (NTRS)

    Glaze, L. S.; Stofan, E. R.; Smrekar, S. E.; Baloga, S. M.

    2002-01-01

    Statistical analysis of an expanded database of coronae on Venus indicates that the populations of Type 1 (with fracture annuli) and 2 (without fracture annuli) corona diameters are statistically indistinguishable, and therefore we have no basis for assuming different formation mechanisms. Analysis of the topography and diameters of coronae shows that coronae that are depressions, rimmed depressions, and domes tend to be significantly smaller than those that are plateaus, rimmed plateaus, or domes with surrounding rims. This is consistent with the model of Smrekar and Stofan and inconsistent with predictions of the spreading drop model of Koch and Manga. The diameter range for domes, the initial stage of corona formation, provides a broad constraint on the buoyancy of corona-forming plumes. Coronae are only slightly more likely to be topographically raised than depressions, with Type 1 coronae most frequently occurring as rimmed depressions and Type 2 coronae most frequently occuring with flat interiors and raised rims. Most Type 1 coronae are located along chasmata systems or fracture belts, while Type 2 coronas are found predominantly as isolated features in the plains. Coronae at hotspot rises tend to be significantly larger than coronae in other settings, consistent with a hotter upper mantle at hotspot rises and their active state.

  3. The H Corona of Mars

    NASA Astrophysics Data System (ADS)

    Chaffin, Michael Scott

    The atmosphere of every planet is surrounded by a tenuous cloud of hydrogen gas, referred to as a hydrogen corona. At Mars, a substantial fraction of the H present in the corona is moving fast enough to escape the planet's gravity, permanently removing H from the Martian atmosphere. Because this H is ultimately derived from lower atmospheric water, loss of H from Mars is capable of drying and oxidizing the planet over geologic time. Understanding the processes that supply the H corona and control its escape is therefore essential for a complete understanding of the climate history of Mars and for assessing its habitability. In this thesis, I present the most complete analysis of the H corona ever attempted, surveying eight years of data gathered by the ultraviolet spectrograph SPICAM on Mars Express. Using a coupled radiative transfer and physical density model, I interpret brightness measurements of the corona in terms of escape rates of H from the planet, uncovering an order-of-magnitude variability in the H escape rate never before detected. These variations are interpreted using a completely new photochemical model of the atmosphere, demonstrating that newly discovered high altitude water vapor layers are sufficient to produce the observed variation. Finally, I present first results of the SPICAM successor instrument IUVS, an imaging ultraviolet spectrograph carried by NASA's MAVEN spacecraft. IUVS measurements are producing the most complete dataset ever gathered for the Martian H corona, enabling supply and loss processes to be assessed in more complete detail than ever before. This dataset will allow present-day loss rates to be extrapolated into the past, determining the absolute amount of water Mars has lost to space over the course of its history. Planets the size of Mars may be common throughout the universe; the work of this thesis is one step toward assessing the habitability of such planets in general.

  4. Hot oxygen corona of Mars

    SciTech Connect

    Ip, W.H.

    1988-10-01

    Electron dissociative recombination of O2(+) ions in the Venus ionosphere, which may be an important source of suprathermal atomic oxygen, is presently considered as a factor in the Mars exosphere; due to the weaker surface gravitational attraction of Mars, a hot oxygen corona thus formed would be denser than that of Venus at altitudes greater than 2000 km despite Mars' lower ionospheric content. If such an extended oxygen corona does exist on Mars, its collisional interaction with Phobos would lead to the formation of an oxygen gas torus whose average number density is of the order of only 1-2/cu cm along the Phobos orbit. 51 references.

  5. Coronae of Mnemosyne Regio - Morphology and origin

    NASA Astrophysics Data System (ADS)

    Stofan, E. R.; Head, J. W.

    1990-01-01

    The Mnemosine Regio area of Venus contains seven of the circular-to-elliptical structures, characterized by an annulus of concentric ridges, that are known as 'coronae'. Several corona-origin models are presently considered, and it is found that the processes associated with diapirism or hot-spots, and the gravitational relaxation of high topography, are most consistent with the topography and morphology of these coronae. The sequence of the formation and evolution of the coronae proceeds from regional volcanic and tectonic activity, through localized uplift and volcanism, to annulus and trough formation related to gravitational relaxation, and finally local volcanic flooding of the corona, annulus, and trough.

  6. Interferometry of the e corona.

    PubMed

    Henderson, G

    1970-12-01

    Descriptions are given of Fabry-Perot spectrometer systems used in the total eclipses of 1965, 1966, and 1970 to observe the emission lines 5303 A, Fe XIV and 6374 A, Fe x at different points in the solar corona. Some results of coronal temperature measurements for the 12 November 1966 eclipse are presented. PMID:20094331

  7. Chromospheres, transition regions, and coronas.

    PubMed

    Böhm-Vitense, E

    1984-02-24

    The increase in temperature outward from the surface of a stellar photosphere can be understood by looking at the local energy balance. The relatively high-density stellar photosphere is cooled effectively by radiative energy loss penetrating the optically thin corona. For the low-density chromosphere and corona, if the energy input cannot be balanced by radiative energy losses, the temperature will rise steeply, possibly up to 1 million degrees or more. Coronal heating and emission appear to be strongly influenced by magnetic fields, leading to large differences in x-ray emission for otherwise similar stars. Comparatively small variations are seen in the overall chromospheric emission of stars. Chromospheres are probably mainly heated by shock-wave energy dissipation, modified by magnetic fields. PMID:17737739

  8. Stellar chromospheres, coronae, and winds

    NASA Technical Reports Server (NTRS)

    Cassinelli, J. P.; Macgregor, K. B.

    1986-01-01

    It has now been found that one or more of the phenomena of chromospheres, coronae, and winds are present in stars of every class. A review is provided of the observational and theoretical results pertaining to the thermal and dynamical structure of early- and late-type stellar atmospheres. Single stars either on the main sequence or in the postmain sequence stages of evolution are considered. In the context of a study of late-type stars, the specific case of the sun is also examined. The observational evidence for the presence of chromospheres in late-type stellar atmospheres is discussed, taking into account spectral diagnostics and line formation, an observational summary and aspects of location in the H-R diagram, and the Wilson-Bappu effect. Attention is also given to observational evidence for the presence of transition regions and coronae in late-type stellar atmospheres, chromospheric and coronal heating mechanisms, observational evidence for mass loss, and the winds and coronae of early-type stars.

  9. Stellar chromospheres, coronae, and winds

    NASA Astrophysics Data System (ADS)

    Cassinelli, J. P.; MacGregor, K. B.

    It has now been found that one or more of the phenomena of chromospheres, coronae, and winds are present in stars of every class. A review is provided of the observational and theoretical results pertaining to the thermal and dynamical structure of early- and late-type stellar atmospheres. Single stars either on the main sequence or in the postmain sequence stages of evolution are considered. In the context of a study of late-type stars, the specific case of the sun is also examined. The observational evidence for the presence of chromospheres in late-type stellar atmospheres is discussed, taking into account spectral diagnostics and line formation, an observational summary and aspects of location in the H-R diagram, and the Wilson-Bappu effect. Attention is also given to observational evidence for the presence of transition regions and coronae in late-type stellar atmospheres, chromospheric and coronal heating mechanisms, observational evidence for mass loss, and the winds and coronae of early-type stars.

  10. Corona Discharge Influences Ozone Concentrations Near Rats

    SciTech Connect

    Goheen, Steven C.; Gaither, Kari A.; Anantatmula, Shantha M.; Mong, Gary M.; Sasser, Lyle B.; Lessor, Delbert L.

    2004-02-26

    Ozone is produced by corona discharge in air. Its production is enhanced near grounded water. Whether grounded animals behave like grounded water, producing more ozone was investigated. Rats were exposed to corona discharge in a plastic cage. The concentration of ozone in the gas phase was monitored. The ozone concentration exceeded ambient levels only in the presence of corona discharge and either rats or water. When water or rats were exposed to corona discharge, ozone levels were more than 10 times higher than controls. Ozone levels increased rapidly with applied voltage. There was also a correlation between the distance of the corona needle to the rats and the amount of ozone produced. As the distance increased, ozone production decreased. These results are discussed in relation to the potential exposure of mammals to ozone in the vicinity of corona discharge and electric fields.

  11. Gravity over coronae and chasmata on Venus

    NASA Technical Reports Server (NTRS)

    Schubert, Gerald; Moore, William B.; Sandwell, David T.

    1994-01-01

    The global spherical harmonic model of Venus' gravity field MGNP60FSAAP, with horizontal resolution of about 600 km, shows that most coronae have little or no signature in the gravity field. Nevertheless, some coronae and some segments of chasmata are associated with distinct positive gravity anomalies. No corona has been found to have a negative gravity anomaly. The spatial coincidence of the gravity highs over four closely spaced 300- to 400-km-diameter coronae in Eastern Eistla Regio with the structures themselves is remarkable and argues for a near-surface or lithospheric origin of the gravity signals over such relatively small features. Apparent depths of compensation (ADCs) of the prominent gravity anomalies at Artemis, Latona, and Heng-o Coronae are about 150 to 200 km. The geoid/topography ratios (GTRs) at Artemis, Latona, and Heng-o Coronae lie in the range 32 to 35 m/km. The large ADCs and GTRs of Artemis, Latona, and Heng-o Coronae are consistent with topographically related gravity and a thick Venus lithosphere or shallowly compensated topography and deep positive mass anomalies due to subduction of underthrusting at these coronae. At arcuate segments of Hecate and Parga Chasmata ADCs are about 125 to 150 km, while those at Fauta Corona, four coronae in Eastern Eistla Regio, and an arcuate segment of Wester Parga Chasmata are about 75 km. The GTRs at Fauta Corona, the four coronae in eastern Eistla Regio, and the accurate segments of Hecate, Parga, and Western Parga Chasmata are about 12 to 21 m/km. By analogy with gravity anomalies of similar horizontal scale (600 km-several thousand kilometers) on the concave sides of terrestrial subduction zone arcs, which are due in large part to subducted lithosphere, it is inferred that the gravity anomalies on Venus are consistent with retrograde subduction at Artemis Chasma, along the northern and southern margins of Latona Coronam, and elsewhere along Parga and Hecate Chasmata.

  12. 14 CFR 1260.53 - Incremental funding.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 5 2010-01-01 2010-01-01 false Incremental funding. 1260.53 Section 1260.53 Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION GRANTS AND COOPERATIVE AGREEMENTS General Special Conditions § 1260.53 Incremental funding. Incremental Funding October 2000...

  13. 14 CFR 1260.53 - Incremental funding.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 5 2011-01-01 2010-01-01 true Incremental funding. 1260.53 Section 1260.53 Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION GRANTS AND COOPERATIVE AGREEMENTS General Special Conditions § 1260.53 Incremental funding. Incremental Funding October 2000 (a) Only $___ of...

  14. 14 CFR 1274.918 - Incremental funding.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 5 2012-01-01 2012-01-01 false Incremental funding. 1274.918 Section 1274... COMMERCIAL FIRMS Other Provisions and Special Conditions § 1274.918 Incremental funding. Incremental Funding... Agreement, as required, until it is fully funded. Any work beyond the funding limit will be at the...

  15. 14 CFR 1274.918 - Incremental funding.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 5 2013-01-01 2013-01-01 false Incremental funding. 1274.918 Section 1274... COMMERCIAL FIRMS Other Provisions and Special Conditions § 1274.918 Incremental funding. Incremental Funding... Agreement, as required, until it is fully funded. Any work beyond the funding limit will be at the...

  16. 14 CFR 1274.918 - Incremental funding.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 5 2011-01-01 2010-01-01 true Incremental funding. 1274.918 Section 1274... COMMERCIAL FIRMS Other Provisions and Special Conditions § 1274.918 Incremental funding. Incremental Funding... Agreement, as required, until it is fully funded. Any work beyond the funding limit will be at the...

  17. 14 CFR 1274.918 - Incremental funding.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 5 2010-01-01 2010-01-01 false Incremental funding. 1274.918 Section 1274... COMMERCIAL FIRMS Other Provisions and Special Conditions § 1274.918 Incremental funding. Incremental Funding... Agreement, as required, until it is fully funded. Any work beyond the funding limit will be at the...

  18. 14 CFR 1260.53 - Incremental funding.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 5 2012-01-01 2012-01-01 false Incremental funding. 1260.53 Section 1260.53 Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION GRANTS AND COOPERATIVE AGREEMENTS General Special Conditions § 1260.53 Incremental funding. Incremental Funding October 2000...

  19. 14 CFR 1260.53 - Incremental funding.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 5 2013-01-01 2013-01-01 false Incremental funding. 1260.53 Section 1260.53 Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION GRANTS AND COOPERATIVE AGREEMENTS General Special Conditions § 1260.53 Incremental funding. Incremental Funding October 2000...

  20. 18 CFR 154.309 - Incremental expansions.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 18 Conservation of Power and Water Resources 1 2012-04-01 2012-04-01 false Incremental expansions... Changes § 154.309 Incremental expansions. (a) For every expansion for which incremental rates are charged... costs and revenues associated with the expansion, until the Commission authorizes the costs of...

  1. 18 CFR 154.309 - Incremental expansions.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 18 Conservation of Power and Water Resources 1 2011-04-01 2011-04-01 false Incremental expansions... Changes § 154.309 Incremental expansions. (a) For every expansion for which incremental rates are charged... costs and revenues associated with the expansion, until the Commission authorizes the costs of...

  2. 18 CFR 154.309 - Incremental expansions.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 18 Conservation of Power and Water Resources 1 2013-04-01 2013-04-01 false Incremental expansions... Changes § 154.309 Incremental expansions. (a) For every expansion for which incremental rates are charged... costs and revenues associated with the expansion, until the Commission authorizes the costs of...

  3. 18 CFR 154.309 - Incremental expansions.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 18 Conservation of Power and Water Resources 1 2014-04-01 2014-04-01 false Incremental expansions... Changes § 154.309 Incremental expansions. (a) For every expansion for which incremental rates are charged... costs and revenues associated with the expansion, until the Commission authorizes the costs of...

  4. 18 CFR 154.309 - Incremental expansions.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 18 Conservation of Power and Water Resources 1 2010-04-01 2010-04-01 false Incremental expansions... Changes § 154.309 Incremental expansions. (a) For every expansion for which incremental rates are charged... costs and revenues associated with the expansion, until the Commission authorizes the costs of...

  5. System for increasing corona inception voltage of insulating oils

    DOEpatents

    Rohwein, Gerald J.

    1998-01-01

    The Corona Inception Voltage of insulating oils is increased by repetitive cycles of prestressing the oil with a voltage greater than the corona inception voltage, and either simultaneously or serially removing byproducts of corona by evacuation and heating the oil.

  6. Property Differencing for Incremental Checking

    NASA Technical Reports Server (NTRS)

    Yang, Guowei; Khurshid, Sarfraz; Person, Suzette; Rungta, Neha

    2014-01-01

    This paper introduces iProperty, a novel approach that facilitates incremental checking of programs based on a property di erencing technique. Speci cally, iProperty aims to reduce the cost of checking properties as they are initially developed and as they co-evolve with the program. The key novelty of iProperty is to compute the di erences between the new and old versions of expected properties to reduce the number and size of the properties that need to be checked during the initial development of the properties. Furthermore, property di erencing is used in synergy with program behavior di erencing techniques to optimize common regression scenarios, such as detecting regression errors or checking feature additions for conformance to new expected properties. Experimental results in the context of symbolic execution of Java programs annotated with properties written as assertions show the e ectiveness of iProperty in utilizing change information to enable more ecient checking.

  7. Parga Chasma: Coronae and Rifting on Venus

    NASA Technical Reports Server (NTRS)

    Smrekar, S. E.; Stofan, E. R.; Buck, W. R.; Martin, P.

    2005-01-01

    The majority of coronae (quasicircular volcano-tectonic features) are found along rifts or fracture belts, and the majority of rifts have coronae [e.g. 1,2]. However, the relationship between coronae and rifts remains unclear [3-6]. There is evidence that coronae can form before, after, or synchronously with rifts [3,4]. The extensional fractures in the rift zones have been proposed to be a result of broad scale upwelling and traction on the lower lithosphere [7]. However, not all rift systems have a significant positive geoid anomaly, as would be expected for an upwelling site [8]. This could be explained if the rifts lacking anomalies are no longer active. Coronae are generally accepted to be sites of local upwelling [e.g. 1], but the observed rifting is frequently not radial to the coronae and extends well beyond the coronae into the surrounding plains. Thus the question remains as to whether the rifts represent regional extension, perhaps driven by mantle tractions, or if the coronae themselves create local thinning and extension of the lithosphere. In the first case, a regional extension model should be consistent with the observed characteristics of the rifts. In the latter case, a model of lithospheric loading and fracturing would be more appropriate. A good analogy may be the propagation of oceanic intraplate volcanoes [9].

  8. Compiler-Enhanced Incremental Checkpointing for OpenMP Applications

    SciTech Connect

    Bronevetsky, G; Marques, D; Pingali, K; Rugina, R; McKee, S A

    2008-01-21

    As modern supercomputing systems reach the peta-flop performance range, they grow in both size and complexity. This makes them increasingly vulnerable to failures from a variety of causes. Checkpointing is a popular technique for tolerating such failures, enabling applications to periodically save their state and restart computation after a failure. Although a variety of automated system-level checkpointing solutions are currently available to HPC users, manual application-level checkpointing remains more popular due to its superior performance. This paper improves performance of automated checkpointing via a compiler analysis for incremental checkpointing. This analysis, which works with both sequential and OpenMP applications, reduces checkpoint sizes by as much as 80% and enables asynchronous checkpointing.

  9. Compiler-Enhanced Incremental Checkpointing for OpenMP Applications

    SciTech Connect

    Bronevetsky, G; Marques, D; Pingali, K; McKee, S; Rugina, R

    2009-02-18

    As modern supercomputing systems reach the peta-flop performance range, they grow in both size and complexity. This makes them increasingly vulnerable to failures from a variety of causes. Checkpointing is a popular technique for tolerating such failures, enabling applications to periodically save their state and restart computation after a failure. Although a variety of automated system-level checkpointing solutions are currently available to HPC users, manual application-level checkpointing remains more popular due to its superior performance. This paper improves performance of automated checkpointing via a compiler analysis for incremental checkpointing. This analysis, which works with both sequential and OpenMP applications, significantly reduces checkpoint sizes and enables asynchronous checkpointing.

  10. ST2 and patient prognosis in chronic heart failure.

    PubMed

    Bayes-Genis, Antoni; Zhang, Yuhui; Ky, Bonnie

    2015-04-01

    Biomarkers of cardiovascular diseases are indispensable tools for diagnosis and prognosis, and the use of several biomarkers is now considered the standard of care. New markers continue to be developed, but few prove to be substantially better than established markers. Suppression of tumorigenicity 2 (ST2) is a marker of cardiomyocyte stress and fibrosis that provides incremental value to natriuretic peptides for risk stratification of patients with a wide spectrum of cardiovascular diseases. On the basis of all available data, the 2013 American College of Cardiology and American Heart Association guidelines now recommend measurement of ST2 for additive risk stratification in patients with acute or chronic ambulatory heart failure (HF). This report provides an up-to-date overview of the clinical studies that led to the endorsement of ST2 as a cardiovascular prognostic marker in chronic HF. The presented data suggest that the addition of ST2 to a model that includes established mortality risk factors, including natriuretic peptides, substantially improves the risk stratification for death and HF hospitalization in patients with HF. ST2's prognostic value remains strong even in the subset of patients with renal insufficiency and is superior to other remodeling-fibrosis biomarkers currently being evaluated. In conclusion, these results have been repeatedly validated; thus, ST2 could be rapidly incorporated into clinical practice for risk prediction. Indeed, the body of evidence supporting the use of ST2 in chronic HF stratification continues to grow, with consistent data from cohorts around the world in single-center (Barcelona, Brussels, and San Diego cohorts) and multicenter (Penn Heart Failure Study [PHFS] and Muerte Subita en Insuficiencia Cardiac [MUSIC]) studies and in post hoc studies from clinical trials (Prospective Randomized Amlodipine Survival Evaluation 2 [PRAISE-2], Heart Failure: A Controlled Trial Investigating Outcomes of Exercise Training [HF

  11. ST2 and patient prognosis in chronic heart failure.

    PubMed

    Bayes-Genis, Antoni; Zhang, Yuhui; Ky, Bonnie

    2015-04-01

    Biomarkers of cardiovascular diseases are indispensable tools for diagnosis and prognosis, and the use of several biomarkers is now considered the standard of care. New markers continue to be developed, but few prove to be substantially better than established markers. Suppression of tumorigenicity 2 (ST2) is a marker of cardiomyocyte stress and fibrosis that provides incremental value to natriuretic peptides for risk stratification of patients with a wide spectrum of cardiovascular diseases. On the basis of all available data, the 2013 American College of Cardiology and American Heart Association guidelines now recommend measurement of ST2 for additive risk stratification in patients with acute or chronic ambulatory heart failure (HF). This report provides an up-to-date overview of the clinical studies that led to the endorsement of ST2 as a cardiovascular prognostic marker in chronic HF. The presented data suggest that the addition of ST2 to a model that includes established mortality risk factors, including natriuretic peptides, substantially improves the risk stratification for death and HF hospitalization in patients with HF. ST2's prognostic value remains strong even in the subset of patients with renal insufficiency and is superior to other remodeling-fibrosis biomarkers currently being evaluated. In conclusion, these results have been repeatedly validated; thus, ST2 could be rapidly incorporated into clinical practice for risk prediction. Indeed, the body of evidence supporting the use of ST2 in chronic HF stratification continues to grow, with consistent data from cohorts around the world in single-center (Barcelona, Brussels, and San Diego cohorts) and multicenter (Penn Heart Failure Study [PHFS] and Muerte Subita en Insuficiencia Cardiac [MUSIC]) studies and in post hoc studies from clinical trials (Prospective Randomized Amlodipine Survival Evaluation 2 [PRAISE-2], Heart Failure: A Controlled Trial Investigating Outcomes of Exercise Training [HF

  12. Global Magnetohydrodynamic Modeling of the Solar Corona

    NASA Technical Reports Server (NTRS)

    Linker, Jon A.; Wagner, William (Technical Monitor)

    2001-01-01

    The solar corona, the hot, tenuous outer atmosphere of the Sun, exhibits many fascinating phenomena on a wide range of scales. One of the ways that the Sun can affect us here at Earth is through the large-scale structure of the corona and the dynamical phenomena associated with it, as it is the corona that extends outward as the solar wind and encounters the Earth's magnetosphere. The goal of our research sponsored by NASA's Supporting Research and Technology Program in Solar Physics is to develop increasingly realistic models of the large-scale solar corona, so that we can understand the underlying properties of the coronal magnetic field that lead to the observed structure and evolution of the corona. We describe the work performed under this contract.

  13. Electrical-assisted double side incremental forming and processes thereof

    SciTech Connect

    Roth, John; Cao, Jian

    2014-06-03

    A process for forming a sheet metal component using an electric current passing through the component is provided. The process can include providing a double side incremental forming machine, the machine operable to perform a plurality of double side incremental deformations on the sheet metal component and also apply an electric direct current to the sheet metal component during at least part of the forming. The direct current can be applied before or after the forming has started and/or be terminated before or after the forming has stopped. The direct current can be applied to any portion of the sheet metal. The electrical assistance can reduce the magnitude of force required to produce a given amount of deformation, increase the amount of deformation exhibited before failure and/or reduce any springback typically exhibited by the sheet metal component.

  14. Heart Failure

    MedlinePlus

    ... version of this page please turn Javascript on. Heart Failure What is Heart Failure? In heart failure, the heart cannot pump enough ... failure often experience tiredness and shortness of breath. Heart Failure is Serious Heart failure is a serious and ...

  15. The protein corona of circulating PEGylated liposomes.

    PubMed

    Palchetti, Sara; Colapicchioni, Valentina; Digiacomo, Luca; Caracciolo, Giulio; Pozzi, Daniela; Capriotti, Anna Laura; La Barbera, Giorgia; Laganà, Aldo

    2016-02-01

    Following systemic administration, liposomes are covered by a 'corona' of proteins, and preserving the surface functionality is challenging. Coating the liposome surface with polyethylene glycol (PEG) is the most widely used anti-opsonization strategy, but it cannot fully preclude protein adsorption. To date, protein binding has been studied following in vitro incubation to predict the fate of liposomes in vivo, while dynamic incubation mimicking in vivo conditions remains largely unexplored. The main aim of this investigation was to determine whether shear stress, produced by physiologically relevant dynamic flow, could influence the liposome-protein corona. The corona of circulating PEGylated liposome was thoroughly compared with that formed by incubation in vitro. Systematic comparison in terms of size, surface charge and quantitative composition was made by dynamic light scattering, microelectrophoresis and nano-liquid chromatography tandem mass spectrometry (nanoLC-MS/MS). Size of coronas formed under static vs. dynamic incubation did not appreciably differ from each other. On the other side, the corona of circulating liposomes was more negatively charged than its static counterpart. Of note, the variety of protein species in the corona formed in a dynamic flow was significantly wider. Collectively, these results demonstrated that the corona of circulating PEGylated liposomes can be considerably different from that formed in a static fluid. This seems to be a key factor to predict the biological activity of a liposomal formulation in a physiological environment.

  16. Image modulation in corona discharge photography.

    PubMed

    Pehek, J O; Kyler, H J; Faust, D L

    1976-10-15

    Photographic images obtained by the Kirlian technique are principally a record of corona activity during an exposure interval. Most of the variations in the images of the corona of a living subject who is in contact with the photographic film can be accounted for by the presence of moisture on or within the subject's surface. During exposure, moisture is transferred from the subject to the emulsion surface of the photographic film and causes an alteration of the electric charge pattern on the film, hence the electric field at the surface of the subject. As a result, large variations in the density of corona images, corona streamer trajectories, and image coloration can be brought about. The radial extent of corona images--that is, the range of corona streamers--is an inverse function of the resistance in the circuit formed by the high-voltage supply, the subject, and the film-electrode configuration. This is because the voltage at which corona is initiated is dependent on the rate of rise of the voltage impressed between the subject and the electrode, and the rate of rise is governed by the applied voltage waveform and the voltage drop across the resistance. The range of streamers is proportional to the corona onset voltage. However, we have not seen any influence of large changes in skin resistance on streamer range. Presumably, this is due to the shunting effect of skin capacitance. In general, the photographic response to moisture suggests that corona discharge photography may be useful in the detection and quantification of moisture in animate and inanimate specimens through the orderly modulation of the image due to various levels of moisture. PMID:968480

  17. Topography of Small Coronae on Venus: Preliminary Overview

    NASA Astrophysics Data System (ADS)

    Kreslavsky, M.; Vdovichenko, R.

    1996-03-01

    We surveyed topography of small coronae on Venus and created a data set of quantitative description of coronae topographic patterns. We failed to arrange all coronae profiles into an evolutionary sequences. We have not found prominent dependences between parameters of corona topography except an obvious trend the smaller corona, the simplier its topographic pattern. There is weak correlation of widths of all ring-like topographic features against corona diameter. The facts evidence that wide diversity of topographic patterns are due to individual peculiarities of corona-forming sources rather than variations of geological settings and ages.

  18. Corona discharge influences ozone concentrations near rats.

    PubMed

    Goheen, Steven C; Gaither, Kari; Anantatmula, Shantha M; Mong, Gary M; Sasser, Lyle B; Lessor, Delbert

    2004-02-01

    Ozone can be produced by corona discharge either in dry air or when one electrode is submerged in water. Since ozone is toxic, we examined whether ozone production by corona near laboratory animals could reach levels of concern. Male rats were exposed to a corona discharge and the concentration of ozone produced was measured. The resulting concentration of ozone ranged from ambient levels to 250 ppb when animals were located 1 cm from a 10 kV source. Similar ozone concentrations were observed when a grounded water source was present. Possible explanations for, as well as concerns regarding, ozone production under these conditions are discussed. PMID:14735560

  19. Dynamics of the transition corona

    SciTech Connect

    Masson, Sophie; McCauley, Patrick; Golub, Leon; Reeves, Katharine K.; DeLuca, Edward E.

    2014-06-01

    Magnetic reconnection between the open and closed magnetic fields in the corona is believed to play a crucial role in the corona/heliosphere coupling. At large scale, the exchange of open/closed connectivity is expected to occur in pseudo-streamer (PS) structures. However, there is neither clear observational evidence of how such coupling occurs in PSs, nor evidence for how the magnetic reconnection evolves. Using a newly developed technique, we enhance the off-limb magnetic fine structures observed with the Atmospheric Imaging Assembly and identify a PS-like feature located close to the northern coronal hole. We first identify that the magnetic topology associated with the observation is a PS, null-point (NP) related topology bounded by the open field. By comparing the magnetic field configuration with the EUV emission regions, we determined that most of the magnetic flux associated with plasma emission are small loops below the PS basic NP and open field bounding the PS topology. In order to interpret the evolution of the PS, we referred to a three-dimensional MHD interchange reconnection modeling the exchange of connectivity between small closed loops and the open field. The observed PS fine structures follow the dynamics of the magnetic field before and after reconnecting at the NP obtained by the interchange model. Moreover, the pattern of the EUV plasma emission is the same as the shape of the expected plasma emission location derived from the simulation. These morphological and dynamical similarities between the PS observations and the results from the simulation strongly suggest that the evolution of the PS, and in particular the opening/closing of the field, occurs via interchange/slipping reconnection at the basic NP of the PS. Besides identifying the mechanism at work in the large-scale coupling between the open and closed fields, our results highlight that interchange reconnection in PSs is a gradual physical process that differs from the impulsive

  20. Solar Corona on 10.21.2010

    NASA Video Gallery

    The solar corona on 2010/10/21, observed by SDO’s AIA. The false colors represent images taken with different filters that are sensitive to distinct coronal temperatures: blue for one million de...

  1. Olivines and olivine coronas in mesosiderites

    NASA Technical Reports Server (NTRS)

    Nehru, C. E.; Zucker, S. M.; Harlow, G. E.; Prinz, M.

    1980-01-01

    The paper presents a study of olivines and their surrounding coronas in mesosiderites texturally and compositionally using optical and microprobe methods. Olivine composition ranges from Fo(58-92) and shows no consistent pattern of distribution within and between mesosiderites; olivine occurs as large single crystals or as partially recrystallized mineral clasts, except for two lithic clasts. These are Emery and Vaca Muerta, and both are shock-modified olivine orthopyroxenites. Fine-grained coronas surround olivine, except for those in impact-melt group mesosiderites and those without tridymite in their matrices. Coronas consist largely of orthopyroxene, plagioclase, clinopyroxene, chromite, merillite, and ilmenite, and are similar to the matrix, but lack metal and tridymite. Texturally the innermost parts of the corona can be divided into three stages of development: (1) radiating acicular, (2) intermediate, and (3) granular.

  2. Solar Corona on 08.01.2010

    NASA Video Gallery

    The solar corona on 2010/08/01, observed by SDO’s AIA. The false colors represent images taken with different filters that are sensitive to distinct coronal temperatures: blue- 1 million degrees...

  3. Global Magnetohydrodynamic Modeling of the Solar Corona

    NASA Technical Reports Server (NTRS)

    Linker, Jon A.

    1998-01-01

    The coronal magnetic field defines the structure of the solar corona, the position of the heliospheric current sheet, the regions of fast and slow solar wind, and the most likely sites of coronal mass ejections. There are few measurements of the magnetic fields in the corona, but the line-of-sight component of the global magnetic fields in the photosphere have been routinely measured for many years (for example, at Stanford's Wilcox Solar Observatory, and at the National Solar Observatory at Kitt Peak). The SOI/MDI instrument is now providing high-resolution full-disk magnetograms several times a day. Understanding the large-scale structure of the solar corona and inner heliosphere requires accurately mapping the measured photospheric magnetic field into the corona and outward. Ideally, a model should not only extrapolate the magnetic field, but should self-consistently reconstruct both the plasma and magnetic fields in the corona and solar wind. Support from our NASA SR&T contract has allowed us to develop three-dimensional magnetohydrodynamic (MHD) computations of the solar corona that incorporate observed photospheric magnetic fields into the boundary conditions. These calculations not only describe the magnetic field in the corona and interplanetary spice, but also predict the plasma properties as well. Our computations thus far have been successful in reproducing many aspects of both coronal and interplanetary data, including the structure of the streamer belt, the location of coronal hole boundaries, and the position and shape of the heliospheric current sheet. The most widely used technique for extrapolating the photospheric magnetic field into the corona and heliosphere are potential field models, such as the potential field source-surface model (PFSS),and the potential field current-sheet (PFCS) model

  4. Corona Associations and Their Implications for Venus

    USGS Publications Warehouse

    Chapman, M.G.; Zimbelman, J.R.

    1998-01-01

    Geologic mapping principles were applied to determine genetic relations between coronae and surrounding geomorphologic features within two study areas in order to better understand venusian coronae. The study areas contain coronae in a cluster versus a contrasting chain and are (1) directly west of Phoebe Regio (quadrangle V-40; centered at latitude 15??S, longitude 250??) and (2) west of Asteria and Beta Regiones (between latitude 23??N, longitude 239?? and latitude 43??N, longitude 275??). Results of this research indicate two groups of coronae on Venus: (1) those that are older and nearly coeval with regional plains, and occur globally; and (2) those that are younger and occur between Beta, Atla, and Themis Regiones or along extensional rifts elsewhere, sometimes showing systematic age progressions. Mapping relations and Earth analogs suggest that older plains coronae may be related to a near-global resurfacing event perhaps initiated by a mantle superplume or plumes. Younger coronae of this study that show age progression may be related to (1) a tectonic junction of connecting rifts resulting from local mantle upwelling and spread of a quasi-stationary hotspot plume, and (2) localized spread of post-plains volcanism. We postulate that on Venus most of the young, post-resurfacing coronal plumes may be concentrated within an area defined by the bounds of Beta, Atla, and Themis Regiones. ?? 1998 Academic Press.

  5. Dynamics of the Transition Corona

    NASA Technical Reports Server (NTRS)

    Masson, Sophie; McCauley, Patrick; Golub, Leon; Reeves, Katharine K.; DeLuca, Edward E.

    2014-01-01

    Magnetic reconnection between the open and closed magnetic fields in the corona is believed to play a crucial role in the corona/heliosphere coupling. At large scale, the exchange of open/closed connectivity is expected to occur in pseudo-streamer (PS) structures. However, there is neither clear observational evidence of how such coupling occurs in PSs, nor evidence for how the magnetic reconnection evolves. Using a newly developed technique, we enhance the off-limb magnetic fine structures observed with the Atmospheric Imaging Assembly and identify a PS-like feature located close to the northern coronal hole. We first identify that the magnetic topology associated with the observation is a PS, null-point (NP) related topology bounded by the open field. By comparing the magnetic field configuration with the extreme ultraviolet (EUV) emission regions, we determined that most of the magnetic flux associated with plasma emission are small loops below the PS basic NP and open field bounding the PS topology. In order to interpret the evolution of the PS, we referred to a three-dimensional MHD interchange reconnection modeling the exchange of connectivity between small closed loops and the open field. The observed PS fine structures follow the dynamics of the magnetic field before and after reconnecting at the NP obtained by the interchange model. Moreover, the pattern of the EUV plasma emission is the same as the shape of the expected plasma emission location derived from the simulation. These morphological and dynamical similarities between the PS observations and the results from the simulation strongly suggest that the evolution of the PS, and in particular the opening/closing of the field, occurs via interchange/slipping reconnection at the basic NP of the PS. Besides identifying the mechanism at work in the large-scale coupling between the open and closed fields, our results highlight that interchange reconnection in PSs is a gradual physical process that differs

  6. Incremental Discriminant Analysis in Tensor Space

    PubMed Central

    Chang, Liu; Weidong, Zhao; Tao, Yan; Qiang, Pu; Xiaodan, Du

    2015-01-01

    To study incremental machine learning in tensor space, this paper proposes incremental tensor discriminant analysis. The algorithm employs tensor representation to carry on discriminant analysis and combine incremental learning to alleviate the computational cost. This paper proves that the algorithm can be unified into the graph framework theoretically and analyzes the time and space complexity in detail. The experiments on facial image detection have shown that the algorithm not only achieves sound performance compared with other algorithms, but also reduces the computational issues apparently. PMID:26339229

  7. The prominence-corona interface and its relationship to the chromosphere-corona transition

    NASA Technical Reports Server (NTRS)

    Rabin, Douglas

    1986-01-01

    The classical model of the chromosphere-corona transition does not account for the observed behavior of the differential emission measure for T approx. less than 100,000 K. Several models have been proposed to resolve this discrepancy in physically different ways. Because the observed differential emission measure at the prominence-corona interface is on average nearly the same as in the chromosphere-corona transition, prominences offer a fresh testing ground for models tailored to the chromosphere-corona transition. The researcher considered three such models and concluded that none extends in a natural way to the environment of prominences. The researcher advanced a simple idea involving thermal conduction both along and across the magnetic field from the corona into cool threads.

  8. Complementary analysis of the hard and soft protein corona: sample preparation critically effects corona composition

    NASA Astrophysics Data System (ADS)

    Winzen, S.; Schoettler, S.; Baier, G.; Rosenauer, C.; Mailaender, V.; Landfester, K.; Mohr, K.

    2015-02-01

    Here we demonstrate how a complementary analysis of nanocapsule-protein interactions with and without application media allows gaining insights into the so called hard and soft protein corona. We have investigated how both human plasma and individual proteins (human serum albumin (HSA), apolipoprotein A-I (ApoA-I)) adsorb and interact with hydroxyethyl starch (HES) nanocapsules possessing different functionalities. To analyse the hard protein corona we used sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) and a protein quantitation assay. No significant differences were observed with regards to the hard protein corona. For analysis of the soft protein corona we characterized the nanocapsule-protein interaction with isothermal titration calorimetry (ITC) and dynamic light scattering (DLS). DLS and ITC measurements revealed that a high amount of plasma proteins were adsorbed onto the capsules' surface. Although HSA was not detected in the hard protein corona, ITC measurements indicated the adsorption of an HSA amount similar to plasma with a low binding affinity and reaction heat. In contrast, only small amounts of ApoA-I protein adsorb to the capsules with high binding affinities. Through a comparison of these methods we have identified ApoA-I to be a component of the hard protein corona and HSA as a component of the soft corona. We demonstrate a pronounced difference in the protein corona observed depending on the type of characterization technique applied. As the biological identity of a particle is given by the protein corona it is crucial to use complementary characterization techniques to analyse different aspects of the protein corona.Here we demonstrate how a complementary analysis of nanocapsule-protein interactions with and without application media allows gaining insights into the so called hard and soft protein corona. We have investigated how both human plasma and individual proteins (human serum albumin (HSA), apolipoprotein A

  9. A Statistical Analysis of Corona Topography: New Insights into Corona Formation and Evolution

    NASA Technical Reports Server (NTRS)

    Stofan, E. R.; Glaze, L. S.; Smrekar, S. E.; Baloga, S. M.

    2003-01-01

    Extensive mapping of the surface of Venus and continued analysis of Magellan data have allowed a more comprehensive survey of coronae to be conducted. Our updated corona database contains 514 features, an increase from the 326 coronae of the previous survey. We include a new set of 106 Type 2 or stealth coronae, which have a topographic rather than a fracture annulus. The large increase in the number of coronae over the 1992 survey results from several factors, including the use of the full Magellan data set and the addition of features identified as part of the systematic geologic mapping of Venus. Parameters of the population that we have analyzed to date include size and topography.

  10. Computer-Assisted Tutoring: Teaching Letter Sounds to Kindergarten Students Using Incremental Rehearsal

    ERIC Educational Resources Information Center

    Volpe, Robert J.; Burns, Matthew K.; DuBois, Matthew; Zaslofsky, Anne Follen

    2011-01-01

    The profound consequences of early reading failure necessitate the provision of early literacy interventions to struggling readers. Many schools struggle, however, to address early reading difficulties because of insufficient human resources. Accordingly, the present study investigated the effectiveness of incremental rehearsal (IR) as a Tier 3…

  11. Separate and combined effects of gabapentin and [INCREMENT]9-tetrahydrocannabinol in humans discriminating [INCREMENT]9-tetrahydrocannabinol.

    PubMed

    Lile, Joshua A; Wesley, Michael J; Kelly, Thomas H; Hays, Lon R

    2016-04-01

    The aim of the present study was to examine a potential mechanism of action of gabapentin to manage cannabis-use disorders by determining the interoceptive effects of gabapentin in cannabis users discriminating [INCREMENT]-tetrahydrocannabinol ([INCREMENT]-THC) using a pharmacologically selective drug-discrimination procedure. Eight cannabis users learned to discriminate 30 mg oral [INCREMENT]-THC from placebo and then received gabapentin (600 and 1200 mg), [INCREMENT]-THC (5, 15, and 30 mg), and placebo alone and in combination. Self-report, task performance, and physiological measures were also collected. [INCREMENT]-THC served as a discriminative stimulus, produced positive subjective effects, elevated heart rate, and impaired psychomotor performance. Both doses of gabapentin substituted for the [INCREMENT]-THC discriminative stimulus and engendered subjective and performance-impairing effects that overlapped with those of [INCREMENT]-THC when administered alone. When administered concurrently, gabapentin shifted the discriminative-stimulus effects of [INCREMENT]-THC leftward/upward, and combinations of [INCREMENT]-THC and gabapentin generally produced larger effects on cannabinoid-sensitive outcomes relative to [INCREMENT]-THC alone. These results suggest that one mechanism by which gabapentin might facilitate cannabis abstinence is by producing effects that overlap with those of cannabinoids.

  12. Separate and combined effects of gabapentin and [INCREMENT]9-tetrahydrocannabinol in humans discriminating [INCREMENT]9-tetrahydrocannabinol.

    PubMed

    Lile, Joshua A; Wesley, Michael J; Kelly, Thomas H; Hays, Lon R

    2016-04-01

    The aim of the present study was to examine a potential mechanism of action of gabapentin to manage cannabis-use disorders by determining the interoceptive effects of gabapentin in cannabis users discriminating [INCREMENT]-tetrahydrocannabinol ([INCREMENT]-THC) using a pharmacologically selective drug-discrimination procedure. Eight cannabis users learned to discriminate 30 mg oral [INCREMENT]-THC from placebo and then received gabapentin (600 and 1200 mg), [INCREMENT]-THC (5, 15, and 30 mg), and placebo alone and in combination. Self-report, task performance, and physiological measures were also collected. [INCREMENT]-THC served as a discriminative stimulus, produced positive subjective effects, elevated heart rate, and impaired psychomotor performance. Both doses of gabapentin substituted for the [INCREMENT]-THC discriminative stimulus and engendered subjective and performance-impairing effects that overlapped with those of [INCREMENT]-THC when administered alone. When administered concurrently, gabapentin shifted the discriminative-stimulus effects of [INCREMENT]-THC leftward/upward, and combinations of [INCREMENT]-THC and gabapentin generally produced larger effects on cannabinoid-sensitive outcomes relative to [INCREMENT]-THC alone. These results suggest that one mechanism by which gabapentin might facilitate cannabis abstinence is by producing effects that overlap with those of cannabinoids. PMID:26313650

  13. Complementary analysis of the hard and soft protein corona: sample preparation critically effects corona composition.

    PubMed

    Winzen, S; Schoettler, S; Baier, G; Rosenauer, C; Mailaender, V; Landfester, K; Mohr, K

    2015-02-21

    Here we demonstrate how a complementary analysis of nanocapsule-protein interactions with and without application media allows gaining insights into the so called hard and soft protein corona. We have investigated how both human plasma and individual proteins (human serum albumin (HSA), apolipoprotein A-I (ApoA-I)) adsorb and interact with hydroxyethyl starch (HES) nanocapsules possessing different functionalities. To analyse the hard protein corona we used sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) and a protein quantitation assay. No significant differences were observed with regards to the hard protein corona. For analysis of the soft protein corona we characterized the nanocapsule-protein interaction with isothermal titration calorimetry (ITC) and dynamic light scattering (DLS). DLS and ITC measurements revealed that a high amount of plasma proteins were adsorbed onto the capsules' surface. Although HSA was not detected in the hard protein corona, ITC measurements indicated the adsorption of an HSA amount similar to plasma with a low binding affinity and reaction heat. In contrast, only small amounts of ApoA-I protein adsorb to the capsules with high binding affinities. Through a comparison of these methods we have identified ApoA-I to be a component of the hard protein corona and HSA as a component of the soft corona. We demonstrate a pronounced difference in the protein corona observed depending on the type of characterization technique applied. As the biological identity of a particle is given by the protein corona it is crucial to use complementary characterization techniques to analyse different aspects of the protein corona.

  14. Coronas and iridescence in mountain wave clouds.

    PubMed

    Shaw, Joseph A; Neiman, Paul J

    2003-01-20

    We use Fraunhofer diffraction theory and meterological data to determine the nature of cloud-particle distributions and the mean particle sizes required for interpreting photographs of coronas and iridescence in mountain wave clouds. Traditional descriptions of coronas and iridescence usually explain these optical phenomena as diffraction by droplets of liquid water. Our analysis shows that the photographed displays have mean particle sizes from 7.6 to 24.3 microm, with over half the cases requiring diffraction by small (approximatley 20 microm) quasispherical ice particles rather than liquid water droplets. Previous documentation of coronas produced by ice particles are limited to observations in cirrus clouds that appear to be composed of small ice crystals, whereas our observations suggest that coronas and iridescence quite often can be created by tiny quasispherical ice particles that might be unique to mountain wave clouds. Furthermore, we see that the dominant colors in mountain wave-cloud coronas are red and blue, rather than the traditionally described red and green.

  15. International Space Station Increment Operations Services

    NASA Astrophysics Data System (ADS)

    Michaelis, Horst; Sielaff, Christian

    2002-01-01

    The Industrial Operator (IO) has defined End-to-End services to perform efficiently all required operations tasks for the Manned Space Program (MSP) as agreed during the Ministerial Council in Edinburgh in November 2001. Those services are the result of a detailed task analysis based on the operations processes as derived from the Space Station Program Implementation Plans (SPIP) and defined in the Operations Processes Documents (OPD). These services are related to ISS Increment Operations and ATV Mission Operations. Each of these End-to-End services is typically characterised by the following properties: It has a clearly defined starting point, where all requirements on the end-product are fixed and associated performance metrics of the customer are well defined. It has a clearly defined ending point, when the product or service is delivered to the customer and accepted by him, according to the performance metrics defined at the start point. The implementation of the process might be restricted by external boundary conditions and constraints mutually agreed with the customer. As far as those are respected the IO has the free choice to select methods and means of implementation. The ISS Increment Operations Service (IOS) activities required for the MSP Exploitation program cover the complete increment specific cycle starting with the support to strategic planning and ending with the post increment evaluation. These activities are divided into sub-services including the following tasks: - ISS Planning Support covering the support to strategic and tactical planning up to the generation - Development &Payload Integration Support - ISS Increment Preparation - ISS Increment Execution These processes are tight together by the Increment Integration Management, which provides the planning and scheduling of all activities as well as the technical management of the overall process . The paper describes the entire End-to-End ISS Increment Operations service and the

  16. TRIANGLE-SHAPED DC CORONA DISCHARGE DEVICE FOR MOLECULAR DECOMPOSITION

    EPA Science Inventory

    The paper discusses the evaluation of electrostatic DC corona discharge devices for the application of molecular decomposition. A point-to-plane geometry corona device with a rectangular cross section demonstrated low decomposition efficiencies in earlier experimental work. The n...

  17. Stellar Coronae: The First Twenty - Five Years

    NASA Technical Reports Server (NTRS)

    Drake, Jeremy

    2000-01-01

    Hot X-ray emitting coronae were detected on stars other than the Sun about twenty-five years ago. Within only a few years of the first detections, the Einstein Observatory had mapped out coronal activity across the HR diagram. These observations provided the foundations for a coarse theoretical understanding of the physical mechanisms responsible for hot coronae on stars that has changed relatively little in the intervening years: plasma trapped in magnetic structures generated by dynamo processes somewhere beneath the photosphere is heated by as yet unidentified mechanisms that appear to transfer kinetic energy from underlying convective regions of the stellar envelope into the outer atmosphere. This review will describe the observational advances that have lead to some further theoretical understanding of stellar coronae, including the first results from high resolution X-ray spectroscopy obtained by Chandra and XMM-Newton, and will highlight the observational directions needed to make further progress.

  18. Direct observation of laser guided corona discharges.

    PubMed

    Wang, Tie-Jun; Wei, Yingxia; Liu, Yaoxiang; Chen, Na; Liu, Yonghong; Ju, Jingjing; Sun, Haiyi; Wang, Cheng; Lu, Haihe; Liu, Jiansheng; Chin, See Leang; Li, Ruxin; Xu, Zhizhan

    2015-01-01

    Laser based lightning control holds a promising way to solve the problem of the long standing disaster of lightning strikes. But it is a challenging project due to insufficient understanding of the interaction between laser plasma channel and high voltage electric filed. In this work, a direct observation of laser guided corona discharge is reported. Laser filament guided streamer and leader types of corona discharges were observed. An enhanced ionization took place in the leader (filament) through the interaction with the high voltage discharging field. The fluorescence lifetime of laser filament guided corona discharge was measured to be several microseconds, which is 3 orders of magnitude longer than the fluorescence lifetime of laser filaments. This work could be advantageous towards a better understanding of laser assisted leader development in the atmosphere. PMID:26679271

  19. Direct observation of laser guided corona discharges

    PubMed Central

    Wang, Tie-Jun; Wei, Yingxia; Liu, Yaoxiang; Chen, Na; Liu, Yonghong; Ju, Jingjing; Sun, Haiyi; Wang, Cheng; Lu, Haihe; Liu, Jiansheng; Chin, See Leang; Li, Ruxin; Xu, Zhizhan

    2015-01-01

    Laser based lightning control holds a promising way to solve the problem of the long standing disaster of lightning strikes. But it is a challenging project due to insufficient understanding of the interaction between laser plasma channel and high voltage electric filed. In this work, a direct observation of laser guided corona discharge is reported. Laser filament guided streamer and leader types of corona discharges were observed. An enhanced ionization took place in the leader (filament) through the interaction with the high voltage discharging field. The fluorescence lifetime of laser filament guided corona discharge was measured to be several microseconds, which is 3 orders of magnitude longer than the fluorescence lifetime of laser filaments. This work could be advantageous towards a better understanding of laser assisted leader development in the atmosphere. PMID:26679271

  20. Transient corona effects on a wire over the ground

    NASA Technical Reports Server (NTRS)

    Chen, K. C.

    1980-01-01

    The nuclear EMP effect on VLF/trailing wire antennas is investigated in relation to new features of corona effects. Previous experimental results on transmission lines with corona under E 80 kV/cm recorded in the nanosecond time frame are analyzed. A nonlinear macroscopic model which describes a transmission line with corona is discussed. The model not only accounts for overall waveform, but also describes the sharp changes in the waveform associated with the corona onset.

  1. Double streamer phenomena in atmospheric pressure low frequency corona plasma

    SciTech Connect

    Kim, Dan Bee; Jung, H.; Gweon, B.; Choe, Wonho

    2010-07-15

    Time-resolved images of an atmospheric pressure corona discharge, generated at 50 kHz in a single pin electrode source, show unique positive and negative corona discharge features: a streamer for the positive period and a glow for the negative period. However, unlike in previous reports of dc pulse and low frequency corona discharges, multistreamers were observed at the initial time stage of the positive corona. A possible physical mechanism for the multistreamers is suggested.

  2. Device for generation of pulsed corona discharge

    DOEpatents

    Gutsol, Alexander F.; Fridman, Alexander; Blank, Kenneth; Korobtsev, Sergey; Shiryaevsky, Valery; Medvedev, Dmitry

    2012-05-08

    The invention is a method and system for the generation of high voltage, pulsed, periodic corona discharges capable of being used in the presence of conductive liquid droplets. The method and system can be used, for example, in different devices for cleaning of gaseous or liquid media using pulsed corona discharge. Specially designed electrodes and an inductor increase the efficiency of the system, permit the plasma chemical oxidation of detrimental impurities, and increase the range of stable discharge operations in the presence of droplets of water or other conductive liquids in the discharge chamber.

  3. System for increasing corona inception voltage of insulating oils

    DOEpatents

    Rohwein, G.J.

    1998-05-19

    The Corona Inception Voltage of insulating oils is increased by repetitive cycles of prestressing the oil with a voltage greater than the corona inception voltage, and either simultaneously or serially removing byproducts of corona by evacuation and heating the oil. 5 figs.

  4. Troponins in heart failure.

    PubMed

    Omland, T; Røsjø, H; Giannitsis, E; Agewall, S

    2015-03-30

    The signs and symptoms of heart failure are frequently unspecific and correlate poorly with objective indices of cardiac function. Objective assessment of cardiac function by echocardiography or other imaging modalities also correlate poorly with symptomatic status and functional capacity. Accordingly, there is a need for circulating biomarkers that can provide incremental diagnostic and prognostic information to the existing armamentarium of tests. The introduction of more sensitive assays that allow determination of very low circulating concentrations of the myofibrillar proteins cardiac troponin I and T has not only resulted in improved diagnostic accuracy in the setting of acute coronary syndromes. The high sensitivity assays have also shown that cardiac troponins are frequently found chronically circulating in a variety of acute and chronic, cardiac and non-cardiac disease conditions, including acute heart failure and chronic symptomatic and asymptomatic left ventricular dysfunction. Cardiac troponin I and T provide may provide clinically useful prognostic information both concerning the future risk of developing heart failure in asymptomatic subjects and the risk of fatal events and hospital admissions in those with already established heart failure This review summarizes current literature on the clinical performance and utility of cardiac troponin measurements as diagnostic and prognostic tools in patients with symptomatic heart failure, as well as in those with asymptomatic left ventricular dysfunction, and clinical phenotypes at high risk for developing heart failure, including stable coronary artery disease, left ventricular hypertrophy, and aortic stenosis.

  5. The minimum flux corona; theory or concept

    NASA Technical Reports Server (NTRS)

    Underwood, J. H.; Antiochos, S. K.

    1980-01-01

    The reply to the criticisms of the minimum flux theory is discussed. These criticisms are correct in substance, as well as in detail. Counter arguments that the minimum flux corona theory is untenable, because of errors in its formulation, are presented.

  6. Global Magnetohydrodynamic Modeling of the Solar Corona

    NASA Technical Reports Server (NTRS)

    Linker, Jon A.

    2001-01-01

    This report describes the progress made in the investigation of the solar corona using magnetohydrodynamic (MHD) simulations. Coronal mass ejections (CME) are believed to be the primary cause of nonrecurrent geomagnetic storms and these have been investigated through the use of three-dimensional computer simulation.

  7. Black hole accretion disks with coronae

    NASA Technical Reports Server (NTRS)

    Svensson, Roland; Zdziarski, Andrzej A.

    1994-01-01

    Observations suggest the existence of both hot and cold dark matter in the centers of active galactic nuclei. Recent spectral models require a major fraction of power to be dissipated in the hot matter. We study the case when the hot matter forms a corona around a standard cold alpha-disk. In particular, we investigate the case when a major fraction, f, of the power released when the cold matter accretes is transported to and dissipated in the corona. This has major effects on the cold disk, making it colder, more geometrically thin, denser, and having larger optical depths. One important consequence is the disappearance of the effectively optically thin zone as well as of the radiation pressure dominated zone for values of f sufficiently closed to unity. The disappearance of the radiation pressure dominated zone will result in a cold disk with only a gas pressure dominated zone that is stable against thermal and viscous instabilities. We also show that the pressure ( and the radiation) from the corona will only affect the surface layers of the cold disk. Our results disagree with those of other recent work on accretion disks with coronae. We find those works to be based on unphysical assumptions.

  8. Solar Corona Explorer: A mission for the physical diagnosis of the solar corona

    NASA Technical Reports Server (NTRS)

    1981-01-01

    Mission objectives and spacecraft requirements for the Solar Corona Explorer (SCE), a proposed free flying, unmanned solar research craft to be tenatively launched in 1987, were defined. The SCE's purpose is to investigate structure, dynamics and evolution of the corona, globally and in the required physical detail, to study the close coupling between the inner corona and the heliosphere. Investigative objectives are: (1) to understand the corona as the source of varying interplanetary plasma and of varying solar X-ray and extreme ultraviolet fluxes; (2) to develop the capabilities to model the corona with sufficient precision to forecast the Earth's variable environment in space, on the scales from weeks to years; (3) to develop an understanding of the physical processes that determine the dynamics and physical state of the coronal plasma, particularly acceleration processes; and (4) to develop insight and test theory on the Sun applicable to stellar coronae and winds, and in particular, to understand why cool stars put such a large fraction of their energy into X-rays. Considered related factors are: (1) duration of the mission; (2) onboard measuring instrumentation; (3) ground support equipment and procedures; and (4) programs of interpretation and modeling.

  9. 48 CFR 3452.232-71 - Incremental funding.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 7 2014-10-01 2014-10-01 false Incremental funding. 3452....232-71 Incremental funding. As prescribed in 3432.705-2, insert the following provision in solicitations if a cost-reimbursement contract using incremental funding is contemplated: Incremental...

  10. 48 CFR 3452.232-71 - Incremental funding.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 7 2012-10-01 2012-10-01 false Incremental funding. 3452....232-71 Incremental funding. As prescribed in 3432.705-2, insert the following provision in solicitations if a cost-reimbursement contract using incremental funding is contemplated: Incremental...

  11. 48 CFR 3452.232-71 - Incremental funding.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 7 2013-10-01 2012-10-01 true Incremental funding. 3452....232-71 Incremental funding. As prescribed in 3432.705-2, insert the following provision in solicitations if a cost-reimbursement contract using incremental funding is contemplated: Incremental...

  12. 48 CFR 3452.232-71 - Incremental funding.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 48 Federal Acquisition Regulations System 7 2011-10-01 2011-10-01 false Incremental funding. 3452....232-71 Incremental funding. As prescribed in 3432.705-2, insert the following provision in solicitations if a cost-reimbursement contract using incremental funding is contemplated: Incremental...

  13. Surface tension increment due to solute addition

    NASA Astrophysics Data System (ADS)

    Hsin, Wei Lun; Sheng, Yu-Jane; Lin, Shi-Yow; Tsao, Heng-Kwong

    2004-03-01

    Addition of solute into solvent may lead to an increase in surface tension, such as salt in water and water in alcohol, due to solute depletion at the interface. The repulsion of the solute from the interface may originate from electrostatic forces or solute-solvent attraction. On the basis of the square-well model for the interface-solute interaction, we derive the surface tension increment Δγ by both canonical and grand-canonical routes (Gibbs adsorption isotherm) for a spherical droplet. The surface tension is increased linearly with the bulk concentration of the solute cb and the interaction range λ. The theoretical results are consistent with those obtained by experiments and Monte Carlo simulations up to a few molarity. For weak repulsion, the increment is internal energy driven. When the repulsion is large enough, the surface tension increment is entropy driven and approaches the asymptotic limit, Δγ≃cbkBTλ, due to the nearly complete depletion of the solute at the interface. Our result may shed some light on the surface tension increment for electrolyte solutions with concentration above 0.2M.

  14. Input-Based Incremental Vocabulary Instruction

    ERIC Educational Resources Information Center

    Barcroft, Joe

    2012-01-01

    This fascinating presentation of current research undoes numerous myths about how we most effectively learn new words in a second language. In clear, reader-friendly text, the author details the successful approach of IBI vocabulary instruction, which emphasizes the presentation of target vocabulary as input early on and the incremental (gradual)…

  15. Incremental social learning in particle swarms.

    PubMed

    de Oca, Marco A Montes; Stutzle, Thomas; Van den Enden, Ken; Dorigo, Marco

    2011-04-01

    Incremental social learning (ISL) was proposed as a way to improve the scalability of systems composed of multiple learning agents. In this paper, we show that ISL can be very useful to improve the performance of population-based optimization algorithms. Our study focuses on two particle swarm optimization (PSO) algorithms: a) the incremental particle swarm optimizer (IPSO), which is a PSO algorithm with a growing population size in which the initial position of new particles is biased toward the best-so-far solution, and b) the incremental particle swarm optimizer with local search (IPSOLS), in which solutions are further improved through a local search procedure. We first derive analytically the probability density function induced by the proposed initialization rule applied to new particles. Then, we compare the performance of IPSO and IPSOLS on a set of benchmark functions with that of other PSO algorithms (with and without local search) and a random restart local search algorithm. Finally, we measure the benefits of using incremental social learning on PSO algorithms by running IPSO and IPSOLS on problems with different fitness distance correlations. PMID:20875976

  16. Surfactant titration of nanoparticle-protein corona.

    PubMed

    Maiolo, Daniele; Bergese, Paolo; Mahon, Eugene; Dawson, Kenneth A; Monopoli, Marco P

    2014-12-16

    Nanoparticles (NP), when exposed to biological fluids, are coated by specific proteins that form the so-called protein corona. While some adsorbing proteins exchange with the surroundings on a short time scale, described as a "dynamic" corona, others with higher affinity and long-lived interaction with the NP surface form a "hard" corona (HC), which is believed to mediate NP interaction with cellular machineries. In-depth NP protein corona characterization is therefore a necessary step in understanding the relationship between surface layer structure and biological outcomes. In the present work, we evaluate the protein composition and stability over time and we systematically challenge the formed complexes with surfactants. Each challenge is characterized through different physicochemical measurements (dynamic light scattering, ζ-potential, and differential centrifugal sedimentation) alongside proteomic evaluation in titration type experiments (surfactant titration). 100 nm silicon oxide (Si) and 100 nm carboxylated polystyrene (PS-COOH) NPs cloaked by human plasma HC were titrated with 3-[(3-Cholamidopropyl) dimethylammonio]-1-propanesulfonate (CHAPS, zwitterionic), Triton X-100 (nonionic), sodium dodecyl sulfate (SDS, anionic), and dodecyltrimethylammonium bromide (DTAB, cationic) surfactants. Composition and density of HC together with size and ζ-potential of NP-HC complexes were tracked at each step after surfactant titration. Results on Si NP-HC complexes showed that SDS removes most of the HC, while DTAB induces NP agglomeration. Analogous results were obtained for PS NP-HC complexes. Interestingly, CHAPS and Triton X-100, thanks to similar surface binding preferences, enable selective extraction of apolipoprotein AI (ApoAI) from Si NP hard coronas, leaving unaltered the dispersion physicochemical properties. These findings indicate that surfactant titration can enable the study of NP-HC stability through surfactant variation and also selective separation

  17. Kidney Failure

    MedlinePlus

    ... if You Have Kidney Disease Kidney Failure Expand Dialysis Kidney Transplant Preparing for Kidney Failure Treatment Choosing Not to Treat with Dialysis or Transplant Paying for Kidney Failure Treatment Contact ...

  18. A Fast Incremental Gaussian Mixture Model

    PubMed Central

    Pinto, Rafael Coimbra; Engel, Paulo Martins

    2015-01-01

    This work builds upon previous efforts in online incremental learning, namely the Incremental Gaussian Mixture Network (IGMN). The IGMN is capable of learning from data streams in a single-pass by improving its model after analyzing each data point and discarding it thereafter. Nevertheless, it suffers from the scalability point-of-view, due to its asymptotic time complexity of O(NKD3) for N data points, K Gaussian components and D dimensions, rendering it inadequate for high-dimensional data. In this work, we manage to reduce this complexity to O(NKD2) by deriving formulas for working directly with precision matrices instead of covariance matrices. The final result is a much faster and scalable algorithm which can be applied to high dimensional tasks. This is confirmed by applying the modified algorithm to high-dimensional classification datasets. PMID:26444880

  19. Specific mass increment and nonequilibrium crystal growth

    NASA Astrophysics Data System (ADS)

    Martyushev, Leonid M.; Terentiev, Pavel S.

    2013-09-01

    Unsteady nonequilibrium crystallization of ammonium chloride from an aqueous solution resulting in the formation of irregular, so-called seaweed, structures is experimentally investigated. It is shown that specific increment of mass for the coexisting structures (or parts thereof) is the same and changes with time (t) according to the power law a/t-b, where the factor a=1.87±0.09 and the factor b is determined by the system relaxation time. The normalization of the power law to the total time of structure growth allows obtaining a universal law that describes the specific mass increment with time for both seaweed and dendrite structures (including the non-coexisting ones).

  20. Achieving incremental semantic interpretation through contextual representation.

    PubMed

    Sedivy, J C; Tanenhaus, M K; Chambers, C G; Carlson, G N

    1999-06-22

    While much work has been done investigating the role of context in the incremental processing of syntactic indeterminacies, relatively little is known about online semantic interpretation. The experiments in this article made use of the eye-tracking paradigm with spoken language and visual contexts in order to examine how, and when listeners make use of contextually-defined contrast in interpreting simple prenominal adjectives. Experiment 1 focused on intersective adjectives. Experiment 1A provided further evidence that intersective adjectives are processed incrementally. Experiment 1B compared response times to follow instructions such as 'Pick up the blue comb' under conditions where there were two blue objects (e.g. a blue pen and a blue comb), but only one of these objects had a contrasting member in the display. Responses were faster to objects with a contrasting member, establishing that the listeners initially assume a contrastive interpretation for intersective adjectives. Experiments 2 and 3 focused on vague scalar adjectives examining the time course with which listeners establish contrast for scalar adjectives such as tall using information provided by the head noun (e.g. glass) and information provided by the visual context. Use of head-based information was examined by manipulating the typicality of the target object (e.g. whether it was a good or poor example of a tall glass. Use of context-dependent contrast was examined by either having only a single glass in the display (the no contrast condition) or a contrasting object (e.g. a smaller glass). The pattern of results indicated that listeners interpreted the scalar adjective incrementally taking into account context-specific contrast prior to encountering the head. Moreover, the presence of a contrasting object, sharply reduced, and in some conditions completely eliminated, typicality effects. The results suggest a language processing system in which semantic interpretation, as well as syntactic

  1. Protein-targeted corona phase molecular recognition.

    PubMed

    Bisker, Gili; Dong, Juyao; Park, Hoyoung D; Iverson, Nicole M; Ahn, Jiyoung; Nelson, Justin T; Landry, Markita P; Kruss, Sebastian; Strano, Michael S

    2016-01-01

    Corona phase molecular recognition (CoPhMoRe) uses a heteropolymer adsorbed onto and templated by a nanoparticle surface to recognize a specific target analyte. This method has not yet been extended to macromolecular analytes, including proteins. Herein we develop a variant of a CoPhMoRe screening procedure of single-walled carbon nanotubes (SWCNT) and use it against a panel of human blood proteins, revealing a specific corona phase that recognizes fibrinogen with high selectivity. In response to fibrinogen binding, SWCNT fluorescence decreases by >80% at saturation. Sequential binding of the three fibrinogen nodules is suggested by selective fluorescence quenching by isolated sub-domains and validated by the quenching kinetics. The fibrinogen recognition also occurs in serum environment, at the clinically relevant fibrinogen concentrations in the human blood. These results open new avenues for synthetic, non-biological antibody analogues that recognize biological macromolecules, and hold great promise for medical and clinical applications. PMID:26742890

  2. MASC: Magnetic Activity of the Solar Corona

    NASA Astrophysics Data System (ADS)

    Auchere, Frederic; Fineschi, Silvano; Gan, Weiqun; Peter, Hardi; Vial, Jean-Claude; Zhukov, Andrei; Parenti, Susanna; Li, Hui; Romoli, Marco

    We present MASC, an innovative payload designed to explore the magnetic activity of the solar corona. It is composed of three complementary instruments: a Hard-X-ray spectrometer, a UV / EUV imager, and a Visible Light / UV polarimetric coronagraph able to measure the coronal magnetic field. The solar corona is structured in magnetically closed and open structures from which slow and fast solar winds are respectively released. In spite of much progress brought by two decades of almost uninterrupted observations from several space missions, the sources and acceleration mechanisms of both types are still not understood. This continuous expansion of the solar atmosphere is disturbed by sporadic but frequent and violent events. Coronal mass ejections (CMEs) are large-scale massive eruptions of magnetic structures out of the corona, while solar flares trace the sudden heating of coronal plasma and the acceleration of electrons and ions to high, sometimes relativistic, energies. Both phenomena are most probably driven by instabilities of the magnetic field in the corona. The relations between flares and CMEs are still not understood in terms of initiation and energy partition between large-scale motions, small-scale heating and particle acceleration. The initiation is probably related to magnetic reconnection which itself results magnetic topological changes due to e.g. flux emergence, footpoints motions, etc. Acceleration and heating are also strongly coupled since the atmospheric heating is thought to result from the impact of accelerated particles. The measurement of both physical processes and their outputs is consequently of major importance. However, despite its fundamental importance as a driver for the physics of the Sun and of the heliosphere, the magnetic field of our star’s outer atmosphere remains poorly understood. This is due in large part to the fact that the magnetic field is a very difficult quantity to measure. Our knowledge of its strength and

  3. Protein-targeted corona phase molecular recognition

    PubMed Central

    Bisker, Gili; Dong, Juyao; Park, Hoyoung D.; Iverson, Nicole M.; Ahn, Jiyoung; Nelson, Justin T.; Landry, Markita P.; Kruss, Sebastian; Strano, Michael S.

    2016-01-01

    Corona phase molecular recognition (CoPhMoRe) uses a heteropolymer adsorbed onto and templated by a nanoparticle surface to recognize a specific target analyte. This method has not yet been extended to macromolecular analytes, including proteins. Herein we develop a variant of a CoPhMoRe screening procedure of single-walled carbon nanotubes (SWCNT) and use it against a panel of human blood proteins, revealing a specific corona phase that recognizes fibrinogen with high selectivity. In response to fibrinogen binding, SWCNT fluorescence decreases by >80% at saturation. Sequential binding of the three fibrinogen nodules is suggested by selective fluorescence quenching by isolated sub-domains and validated by the quenching kinetics. The fibrinogen recognition also occurs in serum environment, at the clinically relevant fibrinogen concentrations in the human blood. These results open new avenues for synthetic, non-biological antibody analogues that recognize biological macromolecules, and hold great promise for medical and clinical applications. PMID:26742890

  4. Nanoflare Heating of Solar and Stellar Coronae

    NASA Technical Reports Server (NTRS)

    Klimchuk, James A.

    2010-01-01

    A combination of observational and theoretical evidence suggests that much, and perhaps most, of the Sun's corona is heated by small unresolved bursts of energy called nanoflares. It seems likely that stellar coronae are heated in a similar fashion. Kanoflares are here taken to mean any impulsive heating that occurs within a magnetic flux strand. Many mechanisms have this property, including waves, but we prefer Parker's picture of tangled magnetic fields. The tangling is caused by turbulent convection at the stellar surface, and magnetic energy is released when the stresses reach a critical level. We suggest that the mechanism of energy release is the "secondary instability" of electric current sheets that are present at the boundaries between misaligned strands. I will discuss the collective evidence for solar and stellar nanoflares and hopefully present new results from the Solar Dynamics Observatory that was just launched.

  5. Corona and Motor Voltage Interim Report

    SciTech Connect

    Hsu, J.S.

    2005-05-06

    It has been suggested that to meet the FreedomCAR objectives for cost, size, weight, efficiency, and reliability higher buss voltages be utilized in HEV and FC automotive applications. The reasoning is that since electric power is equal to the product of voltage and current for a given power a higher voltage and lower current would result in smaller cable and inverter switching components. Consequently, the system can be lighter and smaller. On the other hand, higher voltages are known to require better and thicker electrical insulation that reduce the available slot area for motor windings. One cause of slow insulation breakdown is corona that gradually erodes the insulation and shortens the life expectancy of the motor. This study reports on the results of a study on corona initiating voltages for mush-wound and bobbin-wound stators. A unique testing method is illustrated.

  6. Green corona and solar sector structure

    NASA Technical Reports Server (NTRS)

    Antonucci, E.; Svalgaard, L.

    1974-01-01

    Analysis of the green-line corona for the interval 1947-1970 suggests the existence of large-scale organization of the emission. The green-line emission at high northern latitudes (approximately 40 to 60 deg) is correlated with the emission at high southern latitudes 6, 15, and 24 days later, while the low-latitude green corona seems to be correlated on both sides of the equator with no time lag. These coronal features are recurrent with a 27-day period at all latitudes between plus or minus 60 deg, and these large-scale structures are believed to be associated with the solar magnetic sector structure. The high correlation between northern and southern high-latitude emission at 15 days time lag is explained as a signature of a two-sector structure, while four sectors are associated with the 6- and 24-day peaks.

  7. Structure and Dynamics of the Solar Corona

    NASA Technical Reports Server (NTRS)

    Schnack, D. D.

    1994-01-01

    Advanced computational techniques were used to study solar coronal heating and coronal mass ejections. A three dimensional, time dependent resistive magnetohydrodynamic code was used to study the dynamic response of a model corona to continuous, slow, random magnetic footpoint displacements in the photosphere. Three dimensional numerical simulations of the response of the corona to simple smooth braiding flows in the photosphere were calculated to illustrate and understand the spontaneous formation of current filaments. Two dimensional steady state helmet streamer configurations were obtained by determining the time asymptotic state of the interaction of an initially one dimensinal transponic solar wind with a spherical potential dipole field. The disruption of the steady state helmet streamer configuration was studied as a response to shearing of the magnetic footpoints of the closed field lines under the helmet.

  8. Helium corona-assisted air discharge

    SciTech Connect

    Jiang Nan; Gao Lei; Ji Ailing; Cao Zexian

    2011-10-15

    Operation of atmospheric discharge of electronegative gases including air at low voltages yet without consuming any inert gas will enormously promote the application of non-thermal plasmas. By taking advantage of the low onset voltage for helium corona, air discharge was successfully launched at much reduced voltages with a needle-plate system partly contained in a helium-filled glass bulb--for a needle-plate distance of 12 mm, 1.0 kV suffices. Ultraviolet emission from helium corona facilitates the discharging of air, and the discharge current manifests distinct features such as relatively broad Trichel pulses in both half periods. This design allows safe and economic implementation of atmospheric discharge of electronegative gases, which will find a broad palette of applications in surface modification, plasma medicine and gas treatment, etc.

  9. Hot coronae in nearby Seyfert galaxies

    NASA Astrophysics Data System (ADS)

    Tortosa, Alessia

    2016-08-01

    The primary X-ray emission in AGN is believed to be produced by Comptonization of optical/UV disk photons scattered up to the X-ray band by a hot corona located above the accretion disk. The emitted spectrum is, at the first order, a power-law with a high-energy cutoff, where the photon index and the cutoff energy are directly related to the temperature and to the optical depth of the plasma of hot electrons responsible for the inverse Compton scattering.To investigate the physical properties of the corona and provide constraints on its parameters, we have studied the broad band spectra of a sample of local Seyfert galaxies observed with NuSTAR (in coordination with XMM-Newton, Suzaku or Swift). We will discuss the general properties of the sample, and show a few particularly interesting cases.

  10. Energy System Contributions During Incremental Exercise Test

    PubMed Central

    Bertuzzi, Rômulo; Nascimento, Eduardo M.F.; Urso, Rodrigo P.; Damasceno, Mayara; Lima-Silva, Adriano E.

    2013-01-01

    The main purpose of this study was to determine the relative contributions of the aerobic and glycolytic systems during an incremental exercise test (IET). Ten male recreational long-distance runners performed an IET consisting of three-minute incremental stages on a treadmill. The fractions of the contributions of the aerobic and glycolytic systems were calculated for each stage based on the oxygen uptake and the oxygen energy equivalents derived by blood lactate accumulation, respectively. Total metabolic demand (WTOTAL) was considered as the sum of these two energy systems. The aerobic (WAER) and glycolytic (WGLYCOL) system contributions were expressed as a percentage of the WTOTAL. The results indicated that WAER (86-95%) was significantly higher than WGLYCOL (5-14%) throughout the IET (p < 0.05). In addition, there was no evidence of the sudden increase in WGLYCOL that has been previously reported to support to the “anaerobic threshold” concept. These data suggest that the aerobic metabolism is predominant throughout the IET and that energy system contributions undergo a slow transition from low to high intensity. Key Points The aerobic metabolism contribution is the predominant throughout the maximal incremental test. The speed corresponding to the aerobic threshold can be considered the point in which aerobic metabolism reaches its maximal contribution. Glycolytic metabolism did not contribute largely to the energy expenditure at intensities above the anaerobic threshold. PMID:24149151

  11. The quiescent corona and slow solar wind

    NASA Technical Reports Server (NTRS)

    Noci, G.; Kohl, J. L.; Antonucci, E.; Tondello, G.; Huber, M. C. E.; Fineschi, S.; Gardner, L. D.; Korendyke, C. M.; Nicolosi, P.; Romoli, M.; Spadaro, D.; Maccari, L.; Raymond, J. C.; Siegmund, O. H. W.; Benna, C.; Ciaravella, A.; Giordano, S.; Michels, J.; Modigliani, A.; Naletto, G.

    1997-01-01

    The observations of the ultraviolet coronagraph spectrometer (UVCS), operating onboard the Solar and Heliospheric Observatory (SOHO) spacecraft, are discussed. The purpose of the UVCS is the study of the quiescent coronal streamer and the slow solar wind. The observations started in January 1996. Polarized radiance data in the visible continuum were obtained. Some characteristics of the coronal streamer from the UVCS recorded data are discussed. A model for the source of the slow solar wind in the inner corona is proposed.

  12. STOCHASTIC COUPLING OF SOLAR PHOTOSPHERE AND CORONA

    SciTech Connect

    Uritsky, Vadim M.; Ofman, Leon; Davila, Joseph M.; Coyner, Aaron J.

    2013-05-20

    The observed solar activity is believed to be driven by the dissipation of nonpotential magnetic energy injected into the corona by dynamic processes in the photosphere. The enormous range of scales involved in the interaction makes it difficult to track down the photospheric origin of each coronal dissipation event, especially in the presence of complex magnetic topologies. In this paper, we propose an ensemble-based approach for testing the photosphere-corona coupling in a quiet solar region as represented by intermittent activity in Solar and Heliospheric Observatory Michelson Doppler Imager and Solar TErrestrial RElations Observatory Extreme Ultraviolet Imager image sets. For properly adjusted detection thresholds corresponding to the same degree of intermittency in the photosphere and corona, the dynamics of the two solar regions is described by the same occurrence probability distributions of energy release events but significantly different geometric properties. We derive a set of scaling relations reconciling the two groups of results and enabling statistical description of coronal dynamics based on photospheric observations. Our analysis suggests that multiscale intermittent dissipation in the corona at spatial scales >3 Mm is controlled by turbulent photospheric convection. Complex topology of the photospheric network makes this coupling essentially nonlocal and non-deterministic. Our results are in an agreement with the Parker's coupling scenario in which random photospheric shuffling generates marginally stable magnetic discontinuities at the coronal level, but they are also consistent with an impulsive wave heating involving multiscale Alfvenic wave packets and/or magnetohydrodynamic turbulent cascade. A back-reaction on the photosphere due to coronal magnetic reconfiguration can be a contributing factor.

  13. Ubiquity of, and geostatistics for, nonstationary increment random fields

    NASA Astrophysics Data System (ADS)

    O'Malley, Daniel; Cushman, John H.

    2013-07-01

    Nonstationary random fields such as fractional Brownian motion and fractional Lévy motion have been studied extensively in the hydrology literature. On the other hand, random fields that have nonstationary increments have seen little study. A mathematical argument is presented that demonstrates processes with stationary increments are the exception and processes with nonstationary increments are far more abundant. The abundance of nonstationary increment processes has important implications, e.g., in kriging where a translation-invariant variogram implicitly assumes stationarity of the increments. An approach to kriging for processes with nonstationary increments is presented and accompanied by some numerical results.

  14. Differential rotation in the solar corona

    NASA Technical Reports Server (NTRS)

    Weber, Mark; Acton, Loren W.; Alexander, David

    1994-01-01

    The soft X-ray telescope (SXT) instrument on board the Yohkoh satellite was designed to observe the solar corona for over three years. It was shown in previous works that different tracers of solar rotation, each sensitive to a different part of the solar atmosphere, yield varying results for the latitude dependence of the rotation rate; the differential rotation measured using photospheric structures is markedly different from that obtained using coronal tracers. The long term observations of the solar corona by the SXT make it ideal for the investigation of coronal differential rotation. The soft X-ray emission of the solar corona is used to trace out the rotation rate at different latitudes. This is done by dividing the solar disk into a number of latitude strips and carrying out a power-spectrum analysis of the total soft X-ray intensity in each strip over a twelve week period of the Yohkoh observations. The results are compared with the differential rotation rates obtained from other coronal tracers.

  15. Stellar coronae from Einstein - Observations and theory

    NASA Technical Reports Server (NTRS)

    Rosner, R.; Vaiana, G. S.

    1980-01-01

    Einstein Observatory observations of stellar X-ray emission are presented and their implications for the formation of stellar coronae and the problem of stellar angular momentum loss are discussed. Solar coronal X-ray observations and observations of stellar coronae made prior to Einstein are reviewed, and it is noted that they already suggest that the standard theory of acoustic coronal heating is inadequate. The principal results of the Einstein/CfA stellar survey are summarized, with attention given to variations of the level of X-ray flux detected along the main sequence, the decline of X-ray flux with increasing age of giants and supergiants, and indications of a large range of X-ray emission levels within a given type, which are clearly incompatible with models for acoustic flux generation. A new theory to explain stellar coronae and hence X-ray emission from them is then proposed in which stellar magnetic fields play the key role in determining the level of coronal emission, and the modulation of the surface magnetic flux level and the level of stressing of surface magnetic fields essentially determine the variation of mean coronal activity in the H-R diagram.

  16. Global Magnetohydrodynamic Modeling of the Solar Corona

    NASA Technical Reports Server (NTRS)

    Linker, Jon A.

    1997-01-01

    Under this contract, we have continued our investigations of the large scale structure of the solar corona and inner heliosphere using global magnetohydrodynamic (MHD) simulations. These computations have also formed the basis for studies of coronal mass ejections (CMES) using realistic coronal configurations. We have developed a technique for computing realistic magnetohydrodynamic (MHD) computations of the solar corona and inner heliosphere. To perform computations that can be compared with specific observations, it is necessary to incorporate solar observations into the boundary conditions. We have used the Wilcox Solar Observatory synoptic maps (collected during a solar rotation by daily measurements of the line-of-sight magnetic field at central meridian) to specify the radial magnetic field (B,) at the photosphere. For the initial condition, we use a potential magnetic field consistent with the specified distribution of B, at the lower boundary, and a wind solution consistent with the specified plasma density and temperature at the solar surface. Together this initial condition forms a (non-equilibrium) approximation of the state of the solar corona for the time-dependent MHD computation. The MHD equations are then integrated in time to steady state. Here we describe solutions relevant to a recent solar eclipse, as well as Ulysses observations. We have also developed a model configuration of solar minimum, useful for studying CME initiation and propagation.

  17. Turbulent photospheric drivers of multiscale solar corona

    NASA Astrophysics Data System (ADS)

    Uritsky, Vadim M.; Ofman, Leon; Davila, Joseph M.

    2015-04-01

    We investigate the collective dynamics of transient photospheric and coronal events detected using high-resolution solar magnetograms and coronal emission images. We focus on statistical, ensemble-averaged properties of the interacting solar regions [Uritsky et al., 2011, 2013, 2014; Uritsky and Davila, 2012], as opposed to case-oriented methodologies recruited in some previous studies. The behavior of solar events is studied in the three-dimensional space-time enabling accurate representation of the event evolution. By applying advanced data analysis methods including feature tracking algorithms, multiscale correlation analysis and scaling analysis techniques, we identify leading physical scenarios of the photosphere - corona coupling in quiet and active solar regions, and strive to identify new statistical precursors of coronal eruptions. We also discuss the possibility of modeling multiscale photosphere - corona interactions using idealized three-dimensional MHD models. The obtained results shed a new light on the origin of multiscale dissipation in the solar corona by enabling quantitative validation of several popular statistical physical scenarios, such as e.g. intermittent turbulence, self-organized criticality, and topological complexity.

  18. Faraday Rotation Observations of the Solar Corona

    NASA Astrophysics Data System (ADS)

    Mancuso, S.; Spangler, S. R.

    1998-05-01

    Faraday rotation measures the path integral of the product of electron density and line of sight component of the magnetic field from the observer to a source of linearly polarized radio emission. For our observations, the line of sight passes through the solar corona. These observations were made with the NRAO Very Large Array at frequencies of 1465 and 1635 MHz. Observations at two frequencies can confirm the lambda (2) dependence of position angle rotation characteristic of Faraday rotation. We observed the extended radio source 0036+030 (4C+03.01) on March 28, 1997, when the source was 8.6 Rsun from the center of the Sun. Nearly continuous observations were made over an 11 hour period. Our observations measure an average rotation measure (RM) of about +7 radians/m(2) attributable to the corona. The RM showed slow variations during the observing session, with a total change of about 3 radians/m(2) . This variation is attributed to large scale gradients and static plasma structures in the corona, and is the same for two source components separated by 30 arcseconds (22000 km). We have also detected RM variations on time scales of 15 minutes to one hour, which may be coronal Alfven waves. We measure an rms variation of 0.57 radians/m(2) for such fluctuations, which is comparable to previous reports.

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

    NASA Technical Reports Server (NTRS)

    1970-01-01

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

  20. International Space Station (ISS) S-Band Corona Discharge Anomaly Consultation

    NASA Technical Reports Server (NTRS)

    Kichak, Robert A.; Leidecker, Henning; Battel, Steven; Ruitberg, Arthur; Sank, Victor

    2008-01-01

    The Assembly and Contingency Radio Frequency Group (ACRFG) onboard the International Space Station (ISS) is used for command and control communications and transmits (45 dBm or 32 watts) and receives at S-band. The system is nominally pressurized with gaseous helium (He) and nitrogen (N2) at 8 pounds per square inch absolute (psia). MacDonald, Dettwiler and Associates Ltd. (MDA) was engaged to analyze the operational characteristics of this unit in an effort to determine if the anomalous behavior was a result of a corona event. Based on this analysis, MDA did not recommend continued use of this ACRFG. The NESC was requested to provide expert support in the area of high-voltage corona and multipactoring in an S-Band RF system and to assess the probability of corona occurring in the ACRFG during the planned EVA. The NESC recommended minimal continued use of S/N 002 ACRFG until a replacement unit can be installed. Following replacement, S/N 002 will be subjected to destructive failure analysis in an effort to determine the proximate and root cause(s) of the anomalous behavior.

  1. Collecting, preparing, crossdating, and measuring tree increment cores

    USGS Publications Warehouse

    Phipps, R.L.

    1985-01-01

    Techniques for collecting and handling increment tree cores are described. Procedures include those for cleaning and caring for increment borers, extracting the sample from a tree, core surfacing, crossdating, and measuring. (USGS)

  2. Numerical Modeling of the Solar Chromosphere and Corona: What Has Been Done? What Should Be Done?

    NASA Astrophysics Data System (ADS)

    Hansteen, V.; Carlsson, M.; Gudiksen, B.

    2015-10-01

    A number of increasingly sophisticated numerical simulations spanning the solar atmosphere from below the photosphere in the convection zone to far above in the corona have shed considerable insight into the role of the magnetic field in the structure and energetics of the Sun's outer layers. This development is strengthened by the wealth of observational data now coming on-line from both ground and space based observatories. In this talk we will concentrate on the successes and failures of the modeling effort thus far and discuss the inclusion of various effects not traditionally considered in the MHD description such as time dependent ionization, non-LTE radiative transfer, and generalized Ohm's law.

  3. Desulphurization and simultaneous treatment of wastewater from blast furnace by pulsed corona discharge

    SciTech Connect

    Li, S.L.; Feng, Q.B.; Li, L.; Xie, C.L.; Zhen, L.P.

    2009-03-15

    Laboratory tests were conducted for removal of SO{sub 2} from simulated flue gas and simultaneous treatment of wastewater from blast furnace by pulsed corona discharge. Tests were conducted for the flue gas flow from 12 to 18 Nm{sup 3}/h, the simulated gas temperature from 80 to 120 {sup o}C, the inlet flux of wastewater from 33 to 57 L/h, applied voltage from 0 to 27 kV, and SO{sub 2} initial concentration was about 1,430 mg/m{sup 3}. Results showed that wastewater from blast furnace has an excellent ability of desulphurization (about 90%) and pulsed corona discharge can enhance the desulphurization efficiency. Meanwhile, it was observed that the SO{sub 2} removal ratio decreased along with increased cycle index, while it increased as the flux of flue gas was reduced, and increased when the flux of wastewater from blast furnace was increased. In addition, results demonstrated that the content of sulfate radical produced in wastewater increase with an increment of applied pulsed voltage, cycle index, or the flux of flue gas. Furthermore, the results indicated that the higher the inlet content of cyanide the better removal effect of it, and the removal rate can reach 99.9% with a residence time of 2.1 s in the pulsed corona zone during the desulphurization process when the inlet content was higher, whereas there was almost no removal effect when the inlet content was lower. This research may attain the objective of waste control, and can provide a new way to remove SO{sub 2} from flue gas and simultaneously degrade wastewater from blast furnace for integrated steel plants.

  4. 14 CFR § 1274.918 - Incremental funding.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 5 2014-01-01 2014-01-01 false Incremental funding. § 1274.918 Section Â... WITH COMMERCIAL FIRMS Other Provisions and Special Conditions § 1274.918 Incremental funding. Incremental Funding July 2002 (a) Of the award amount indicated on the cover page of this Agreement, only...

  5. 48 CFR 3452.232-71 - Incremental funding.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 48 Federal Acquisition Regulations System 7 2010-10-01 2010-10-01 false Incremental funding. 3452... 3452.232-71 Incremental funding. As prescribed in 3452.771, insert the following provision in solicitations: Incremental Funding (AUG 1987) (a) Sufficient funds are not presently available to cover...

  6. 14 CFR § 1260.53 - Incremental funding.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 5 2014-01-01 2014-01-01 false Incremental funding. § 1260.53 Section § 1260.53 Aeronautics and Space NATIONAL AERONAUTICS AND SPACE ADMINISTRATION GRANTS AND COOPERATIVE AGREEMENTS General Special Conditions § 1260.53 Incremental funding. Incremental Funding October 2000...

  7. Respiratory Failure

    MedlinePlus

    Respiratory failure happens when not enough oxygen passes from your lungs into your blood. Your body's organs, ... brain, need oxygen-rich blood to work well. Respiratory failure also can happen if your lungs can' ...

  8. Large-scale volcanism associated with coronae on Venus

    NASA Technical Reports Server (NTRS)

    Roberts, K. Magee; Head, James W.

    1993-01-01

    The formation and evolution of coronae on Venus are thought to be the result of mantle upwellings against the crust and lithosphere and subsequent gravitational relaxation. A variety of other features on Venus have been linked to processes associated with mantle upwelling, including shield volcanoes on large regional rises such as Beta, Atla and Western Eistla Regiones and extensive flow fields such as Mylitta and Kaiwan Fluctus near the Lada Terra/Lavinia Planitia boundary. Of these features, coronae appear to possess the smallest amounts of associated volcanism, although volcanism associated with coronae has only been qualitatively examined. An initial survey of coronae based on recent Magellan data indicated that only 9 percent of all coronae are associated with substantial amounts of volcanism, including interior calderas or edifices greater than 50 km in diameter and extensive, exterior radial flow fields. Sixty-eight percent of all coronae were found to have lesser amounts of volcanism, including interior flooding and associated volcanic domes and small shields; the remaining coronae were considered deficient in associated volcanism. It is possible that coronae are related to mantle plumes or diapirs that are lower in volume or in partial melt than those associated with the large shields or flow fields. Regional tectonics or variations in local crustal and thermal structure may also be significant in determining the amount of volcanism produced from an upwelling. It is also possible that flow fields associated with some coronae are sheet-like in nature and may not be readily identified. If coronae are associated with volcanic flow fields, then they may be a significant contributor to plains formation on Venus, as they number over 300 and are widely distributed across the planet. As a continuation of our analysis of large-scale volcanism on Venus, we have reexamined the known population of coronae and assessed quantitatively the scale of volcanism associated

  9. Igneous and tectonic evolution of Venusian and terrestrial coronae

    NASA Technical Reports Server (NTRS)

    Kargel, J. S.; Komatsu, G.

    1992-01-01

    A great variety of tectonic and volcanic features have been documented on Venus. It is widely appreciated that there are close spatial associations among certain types of tectonic structures and some classes of volcanic flows and constructs. Coronae are endowed with a particularly rich variety of volcanism. It is thought that coupled tectonic and volcanic aspects of coronae are cogenetic manifestations of mantle plumes. An outstanding feature of most venusian coronae is their circular or elliptical shape defined by peripheral zones of fracturing and/or folding. Some coronae are composite, consisting of two or more small coronae within a larger enclosing corona, suggesting complex histories of structured diapirism analogous in some ways to salt dome tectonics. Coronae range widely in size, from smaller than 100 km to over 1000 km in diameter. Volcanic features associated with venusian coronae include lunar-like sinuous rilles, thin lava flows, cinder cone-like constructs, shield volcanos, and pancake domes. Several types of volcanic features are often situated within or near a single corona, in many instances including land-forms indicating effusions of both low- and high-viscosity lavas. In some cases stratigraphic evidence brackets emplacement of pancake domes during the period of tectonic development of the corona, thus supporting a close link between the igneous and tectonic histories of coronae. These associations suggest emplacement of huge diapirs and massive magmatic intrusions, thus producing the tectonic deformations defining these structures. Igneous differentiation of the intrusion could yield a range of lava compositions. Head and Wilson suggested a mechanism that would cause development of neutral buoyancy zones in the shallow subsurface of Venus, thereby tending to promote development of massive igneous intrusions.

  10. Igneous and tectonic evolution of Venusian and terrestrial coronae

    NASA Astrophysics Data System (ADS)

    Kargel, J. S.; Komatsu, G.

    1992-12-01

    A great variety of tectonic and volcanic features have been documented on Venus. It is widely appreciated that there are close spatial associations among certain types of tectonic structures and some classes of volcanic flows and constructs. Coronae are endowed with a particularly rich variety of volcanism. It is thought that coupled tectonic and volcanic aspects of coronae are cogenetic manifestations of mantle plumes. An outstanding feature of most venusian coronae is their circular or elliptical shape defined by peripheral zones of fracturing and/or folding. Some coronae are composite, consisting of two or more small coronae within a larger enclosing corona, suggesting complex histories of structured diapirism analogous in some ways to salt dome tectonics. Coronae range widely in size, from smaller than 100 km to over 1000 km in diameter. Volcanic features associated with venusian coronae include lunar-like sinuous rilles, thin lava flows, cinder cone-like constructs, shield volcanos, and pancake domes. Several types of volcanic features are often situated within or near a single corona, in many instances including land-forms indicating effusions of both low- and high-viscosity lavas. In some cases stratigraphic evidence brackets emplacement of pancake domes during the period of tectonic development of the corona, thus supporting a close link between the igneous and tectonic histories of coronae. These associations suggest emplacement of huge diapirs and massive magmatic intrusions, thus producing the tectonic deformations defining these structures. Igneous differentiation of the intrusion could yield a range of lava compositions. Head and Wilson suggested a mechanism that would cause development of neutral buoyancy zones in the shallow subsurface of Venus, thereby tending to promote development of massive igneous intrusions.

  11. Incremental Scheduling Engines: Cost Savings through Automation

    NASA Technical Reports Server (NTRS)

    Jaap, John; Phillips, Shaun

    2005-01-01

    As humankind embarks on longer space missions farther from home, the requirements and environments for scheduling the activities performed on these missions are changing. As we begin to prepare for these missions it is appropriate to evaluate the merits and applicability of the different types of scheduling engines. Scheduling engines temporally arrange tasks onto a timeline so that all constraints and ob.jectives are met and resources are not over-booked. Scheduling engines used to schedule space missions fall into three general categories: batch, mixed-initiative, and incremental. This paper, presents an assessment of the engine types, a discussion of the impact of human exploration of the moon and Mars on planning and scheduling, and the applicability of the different types of scheduling engines. This paper will pursue the hypothesis that incremental scheduling engines may have a place in the new environment; they have the potential to reduce cost, to improve the satisfaction of those who execute or benefit from a particular timeline (the customers), and to allow astronauts to plan their own tasks and those of their companion robots.

  12. Incremental learning for automated knowledge capture.

    SciTech Connect

    Benz, Zachary O.; Basilico, Justin Derrick; Davis, Warren Leon,; Dixon, Kevin R.; Jones, Brian S.; Martin, Nathaniel; Wendt, Jeremy Daniel

    2013-12-01

    People responding to high-consequence national-security situations need tools to help them make the right decision quickly. The dynamic, time-critical, and ever-changing nature of these situations, especially those involving an adversary, require models of decision support that can dynamically react as a situation unfolds and changes. Automated knowledge capture is a key part of creating individualized models of decision making in many situations because it has been demonstrated as a very robust way to populate computational models of cognition. However, existing automated knowledge capture techniques only populate a knowledge model with data prior to its use, after which the knowledge model is static and unchanging. In contrast, humans, including our national-security adversaries, continually learn, adapt, and create new knowledge as they make decisions and witness their effect. This artificial dichotomy between creation and use exists because the majority of automated knowledge capture techniques are based on traditional batch machine-learning and statistical algorithms. These algorithms are primarily designed to optimize the accuracy of their predictions and only secondarily, if at all, concerned with issues such as speed, memory use, or ability to be incrementally updated. Thus, when new data arrives, batch algorithms used for automated knowledge capture currently require significant recomputation, frequently from scratch, which makes them ill suited for use in dynamic, timecritical, high-consequence decision making environments. In this work we seek to explore and expand upon the capabilities of dynamic, incremental models that can adapt to an ever-changing feature space.

  13. The solar extreme ultra-violet corona: Resolved loops and the unresolved active region corona

    NASA Astrophysics Data System (ADS)

    Cirtain, Jonathan Wesley

    In this work, physical characteristics of the solar corona as observed in the Extreme Ultra-Violet (EUV) regime are investigated. The focus will be the regions of intense EUV radiation generally found near the locations of sunspots. These regions are commonly called active regions. Multiple space- based observing platforms have been deployed in the last decade; it is possible to use several of these observatories in combination to develop a more complete picture of the solar corona. Joint Observing Program 146 was created to collect spectroscopic intensities using the Coronal Diagnostic Spectrometer on Solar and Heliospheric Observatory and EUV images using NASA's Transition Region and Coronal Explorer. The emission line intensities are analyzed to develop an understanding of the temperature and density of the active region coronal plasma. However, the performance of the CDS instrument in the spatial and temporal domains is limited and to compensate for these limitations, data collected by the TRACE instrument provide a high spatial and temporal resolution set of observations. One of the most exciting unsolved problems in solar astrophysics is to understand why the corona maintains a temperature roughly two orders of magnitude higher than the underlying material. A detailed investigation of the coronal emission has provided constraints on models of the heating mechanism, since the temperature, density and evolution of emission rates for multiple ionic species are indicative of the mechanism(s) working to heat the corona. The corona appears to consist of multiple unresolved structures as well as resolved active region structures, called coronal loops. The purpose of the present work is to determine the characteristics of the unresolved background corona. Using the characterizations of the coronal unresolved background, results for loops after background subtraction are also presented. This work demonstrates the magnitude of the unresolved coronal emission with

  14. Reconnection Processes in the Chromosphere and Corona

    NASA Astrophysics Data System (ADS)

    Shibata, Kazunari

    2012-07-01

    Magnetic reconnection is a fundamental key physical process in magnetized plasmas. Recent space solar observations revealed that magnetic reconnection is ubiquitous in the solar chromospheres and corona. Especially recent Hinode observations has found various types of tiny chromospheric jets, such as chromospheric anemone jets (Shibata et al. 2007), penumbral microjets (Katsukawa et al. 2007), light bridge jets from sunspot umbra (Shimizu et al. 2009), etc. It was also found that the corona is full of tiny X-ray jets (Cirtain et al. 2007). Often they are seen as helical spinning jets (Shimojo et al. 2007, Patsourakos et al. 2008, Pariat et al. 2009, Filippov et al. 2009, Kamio et al. 2010) with Alfvenic waves (Nishizuka et al. 2008, Liu et al. 2009) and there are increasing evidence of magnetic reconnection in these tiny jets. We can now say that as spatial resolution of observations become better and better, smaller and smaller flares and jets have been discovered, which implies that the magnetized solar atmosphere consist of fractal structure and dynamics, i.e., fractal reconnection. Bursty radio and hard X-ray emissions from flares also suggest the fractal reconnection and associated particle acceleration. Since magnetohydrodynamics (MHD) does not contain any characteristic length and time scale, it is natural that MHD structure, dynamics, and reconnection, tend to become fractal in ideal MHD plasmas with large magnetic Reynolds number such as in the solar atmosphere. We would discuss recent observations and theories related to fractal reconnection in the chromospheres and corona, and discuss possible implication to chromospheric and coronal heating.

  15. Corona And Ultraviolet Equipment For Testing Materials

    NASA Technical Reports Server (NTRS)

    Laue, Eric G.

    1993-01-01

    Two assemblies of laboratory equipment developed for use in testing abilities of polymers, paints, and other materials to withstand ultraviolet radiation and charged particles. One is vacuum ultraviolet source built around commercial deuterium lamp. Other exposes specimen in partial vacuum to both ultraviolet radiation and brush corona discharge. Either or both assemblies used separately or together to simulate approximately combination of solar radiation and charged particles encountered by materials aboard spacecraft in orbit around Earth. Also used to provide rigorous environmental tests of materials exposed to artificial ultraviolet radiation and charged particles in industrial and scientific settings or to natural ultraviolet radiation and charged particles aboard aircraft at high altitudes.

  16. Origin of Corona-Dominated Topographic Rises on Venus

    NASA Technical Reports Server (NTRS)

    Smrekar, S.; Stofan, E.

    1999-01-01

    Both large-scale mantel upwellings, comparable to terrestrial hotspots on Earth, and smaller scale mantel upwellings, known as coronae, occur on Venus. Corona-dominated rises have many of the characteristics of large scale mantle upwellings, or hotspots, such as broad topographic rises greater than 1000km in diameter and large positive gravity anomalies.

  17. The nanoparticle biomolecule corona: lessons learned - challenge accepted?

    PubMed

    Docter, D; Westmeier, D; Markiewicz, M; Stolte, S; Knauer, S K; Stauber, R H

    2015-10-01

    Besides the wide use of engineered nanomaterials (NMs) in technical products, their applications are not only increasing in biotechnology and biomedicine, but also in the environmental field. While the physico-chemical properties and behaviour of NMs can be characterized accurately under idealized conditions, this is no longer the case in complex physiological or natural environments. Herein, proteins and other biomolecules rapidly bind to NMs, forming a protein/biomolecule corona that critically affects the NMs' (patho)biological and technical identities. As the corona impacts the in vitro and/or in vivo NM applications in humans and ecosystems, a mechanistic understanding of its relevance and of the biophysical forces regulating corona formation is mandatory. Based on recent insights, we here critically review and present an updated concept of corona formation and evolution. We comment on how corona signatures may be linked to effects at the nano-bio interface in physiological and environmental systems. In order to comprehensively analyse corona profiles and to mechanistically understand the coronas' biological/ecological impact, we present a tiered multidisciplinary approach. To stimulate progress in this field, we introduce the potential impact of the corona for NM-microbiome-(human)host interactions and the novel concept of 'nanologicals', i.e., the nanomaterial-specific targeting of molecular machines. We conclude by discussing the relevant challenges that still need to be resolved in this field.

  18. Protein corona - from molecular adsorption to physiological complexity.

    PubMed

    Treuel, Lennart; Docter, Dominic; Maskos, Michael; Stauber, Roland H

    2015-01-01

    In biological environments, nanoparticles are enshrouded by a layer of biomolecules, predominantly proteins, mediating its subsequent interactions with cells. Detecting this protein corona, understanding its formation with regards to nanoparticle (NP) and protein properties, and elucidating its biological implications were central aims of bio-related nano-research throughout the past years. Here, we discuss the mechanistic parameters that are involved in the protein corona formation and the consequences of this corona formation for both, the particle, and the protein. We review consequences of corona formation for colloidal stability and discuss the role of functional groups and NP surface functionalities in shaping NP-protein interactions. We also elaborate the recent advances demonstrating the strong involvement of Coulomb-type interactions between NPs and charged patches on the protein surface. Moreover, we discuss novel aspects related to the complexity of the protein corona forming under physiological conditions in full serum. Specifically, we address the relation between particle size and corona composition and the latest findings that help to shed light on temporal evolution of the full serum corona for the first time. Finally, we discuss the most recent advances regarding the molecular-scale mechanistic role of the protein corona in cellular uptake of NPs.

  19. Rings Around the Sun and Moon: Coronae and Diffraction

    ERIC Educational Resources Information Center

    Cowley, Les; Laven, Philip; Vollmer, Michael

    2005-01-01

    Atmospheric optical effects can teach much about physics and especially optics. Coronae--coloured rings around the sun or moon--are large-scale consequences of diffraction, which is often thought of as only a small effect confined to the laboratory. We describe coronae, how they are formed and experiments that can be conducted on ones in the sky.…

  20. Silver nanoparticle protein corona and toxicity: a mini-review.

    PubMed

    Durán, Nelson; Silveira, Camila P; Durán, Marcela; Martinez, Diego Stéfani T

    2015-01-01

    Silver nanoparticles are one of the most important materials in the nanotechnology industry. Additionally, the protein corona is emerging as a key entity at the nanobiointerface; thus, a comprehensive understanding of the interactions between proteins and silver nanoparticles is imperative. Therefore, literature reporting studies involving both single molecule protein coronas (i.e., bovine and human serum albumin, tubulin, ubiquitin and hyaluronic-binding protein) and complex protein coronas (i.e., fetal bovine serum and yeast extract proteins) were selected to demonstrate the effects of protein coronas on silver nanoparticle cytotoxicity and antimicrobial activity. There is evidence that distinct and differential protein components may yield a "protein corona signature" that is related to the size and/or surface curvature of the silver nanoparticles. Therefore, the formation of silver nanoparticle protein coronas together with the biological response to these coronas (i.e., oxidative stress, inflammation and cytotoxicity) as well as other cellular biophysicochemical mechanisms (i.e., endocytosis, biotransformation and biodistribution) will be important for nanomedicine and nanotoxicology. Researchers may benefit from the information contained herein to improve biotechnological applications of silver nanoparticles and to address related safety concerns. In summary, the main aim of this mini-review is to highlight the relationship between the formation of silver nanoparticle protein coronas and toxicity. PMID:26337542

  1. RADIO OBSERVATIONS OF THE SOLAR CORONA DURING AN ECLIPSE

    SciTech Connect

    Kathiravan, C.; Ramesh, R.; Barve, Indrajit V.; Rajalingam, M. E-mail: ramesh@iiap.res.in E-mail: rajalingam@iiap.res.in

    2011-04-01

    We carried out radio observations of the solar corona at 170 MHz during the eclipse of 2008 August 1, from the Gauribidanur observatory located about 100 km north of Bangalore in India. The results indicate the presence of a discrete radio source of very small angular dimension ({approx}15'') in the corona from where the observed radiation originated.

  2. Chaotic characteristics of corona discharges in atmospheric air

    SciTech Connect

    Tan Xiangyu; Zhang Qiaogen; Wang Xiuhuan; Sun Fu; Zha Wei; Jia Zhijie

    2008-11-15

    A point-plane electrode system in atmospheric air is established to investigate the mechanism of the corona discharge. By using this system, the current pulses of the corona discharges under the 50 Hz ac voltage are measured using partial discharge (PD) measurement instrument and constitute the point-plane voltage-current (V-I) characteristic equation together with the voltage. Then, this paper constructs the nonlinear circuit model and differential equations of the system in an attempt to give the underlying dynamic mechanism based on the nonlinear V-I characteristics of the point-plane corona discharges. The results show that the chaotic phenomenon is found in the corona circuit by the experimental study and nonlinear dynamic analysis. The basic dynamic characteristics, including the Lyapunov exponent, the existence of the strange attractors, and the equilibrium points, are also found and analyzed in the development process of the corona circuit. Moreover, the time series of the corona current pulses obtained in the experiment is used to demonstrate the chaotic characteristics of the corona current based on the nonlinear dynamic circuit theory and the experimental basis. It is pointed out that the corona phenomenon is not a purely stochastic phenomenon but a short term deterministic chaotic activity.

  3. Flexural ridges, trenches, and outer rises around coronae on Venus

    NASA Technical Reports Server (NTRS)

    Sandwell, David T.; Schubert, Gerald

    1992-01-01

    Flexural signatures outboard of Venusian coronal rims are examined with the purpose of inferring the thickness of the planet's elastic lithosphere. Topographic profiles of several prominent coronae which display clear trench and outer rise signatures are presented. Via a thin elastic plate flexure model to characterize the shape of the trench and outer rise, Venusian flexures are found to be similar in both amplitude and wavelength to lithospheric flexures seaward of subduction zones on earth. It is shown that circumferential fractures are concentrated in areas where the topography is curved downward, in good agreement with the high tensile stress predicted by the flexure models. Two scenarios for the development of the ridge-trench-outer rise flexural topography and circumferential fractures of coronae are presented. The first scenario involves reheating and thermal subsidence of the lithosphere interior to the corona, while the second involves expansion of the corona interior and roll back of the subducting lithosphere exterior to the corona.

  4. Coronae formation on Venus via extension and lithospheric instability

    NASA Astrophysics Data System (ADS)

    Piskorz, Danielle; Elkins-Tanton, Linda T.; Smrekar, Suzanne E.

    2014-12-01

    Over 500 quasi-circular volcano-tectonic features called coronae occur on Venus. They are believed to form via small-scale mantle upwellings, lithospheric instability, or a combination thereof. Coronae and rifts commonly occur together, including many coronae that lie outside of the fracture zone. However, the genetic link between the two has remained unclear. This paper proposes a mechanism for the formation of off-rift coronae due to the rifting process. We model the interaction of a rising mantle plume associated with a rift with a hypothetical preexisting layer of dense material in the lithosphere. We show that a rift and its associated off-rift coronae could be genetically linked by the process of development of secondary ringlike dripping instabilities initiating at the plume margins. We calculate the resulting surface topographies, melt volumes, and Bouguer gravity anomalies and compare them to observations.

  5. Development of ac corona discharge modes at atmospheric pressure

    SciTech Connect

    El-Koramy, Reda Ahmed; Yehia, Ashraf; Omer, Mohamed

    2011-02-15

    Corona discharges in gases exist under several distinctive forms. In this paper, a survey study has been made of ac corona discharge modes generated in some different gases fed in a wire-duct reactor with a constant rate of flowing at atmospheric pressure. The properties of different corona modes are analyzed under some condition transitions from Trichel pulses to a steady glow. In the course of the presented experimental work, numerous apparent contradictions with earlier observations necessitated further study and are given to provide more information on the physical mechanisms of the ac corona discharges. Furthermore, we have gained insight into some new technologies and applications of the environmentally friendly corona and plasma discharges.

  6. Isothermal, Compton-heated coronae above accretion disks

    NASA Technical Reports Server (NTRS)

    Ostriker, Eve C.; Mckee, Christopher F.; Klein, Richard I.

    1991-01-01

    The structure of Compton-heated coronae above accretion disks is studied here by using analytic and numerical approaches are used here to determine the direct and scattered radiation reaching the base of the corona for a range of central source luminosities. It is found that the outer region of the corona is unaffected by multiple scattering in the interior, provided that the luminosity of the central source is sufficient below the Eddington limit. How attenuation and scattering by the corona affects the strength of chromospheric emission lines is determined, as is the condition for which the irradiation due to the central source exceeds the locally generated flux from the disk. Finally, it is shown that the stability analysis for irradiated accretion disks of Tuchman et al. is not substantially altered by the corona.

  7. Incremental responses to light recorded from pigment epithelial cells and horizontal cells of the cat retina

    PubMed Central

    Steinberg, Roy H.

    1971-01-01

    1. Rod-dependent incremental responses were recorded intracellularly in both pigment epithelial cells and horizontal cells of the cat retina. They were elicited by test flashes which were superimposed on background flashes after a delay. 2. In pigment epithelial cells smaller test responses were produced as background intensity was raised. The incremental sensitivity function was linear for about 1·4 log units, with a slope of 0·86, and the approach of saturation occurred at about 2·5 log td scotopic. 3. The amplitude of pigment epithelial test responses could be estimated from the dark-adapted amplitude—log intensity function obtained with single flashes. Test flashes produced the voltage increment predicted by the slope of this function just above the point on the curve equal to the background intensity. The pigment epithelial response to a test flash, therefore, is the response expected if the background were presented alone and made more intense by the amount of the test flash. 4. Rod-dependent incremental sensitivity functions of horizontal cells closely resembled the ones obtained from pigment epithelial cells. 5. It was concluded that the adaptive effects observed in pigment epithelial cells originated in individual rods. These effects arose from the compressive nature of the dark-adapted amplitude—intensity function. In horizontal cell responses these effects may be modified by the failure of the background response to maintain its initial voltage. PMID:5571955

  8. Incremental layer shear bond strength of low-shrinkage resin composites under different bonding conditions.

    PubMed

    Al Musa, A H; Al Nahedh, H N A

    2014-01-01

    The purpose of this study was to determine the incremental shear bond strength of a silorane-based composite (Filtek Silorane) repaired with silorane or a methacrylate-based composite (Filtek Z250) under various aging conditions. Also, the incremental bond strength of the silorane-based composite was compared with that of another low-shrinkage methacrylate-based composite (Aelite LS Posterior) under fresh and aged conditions, with and without the use of an adhesive resin between successive layers. The two brands of low-shrinkage composites were compared with a microhybrid, Filtek Z250, which served as the control. Substrate discs were fabricated and second layers were adhered to them immediately, after two weeks of aging, or after four weeks of aging and with and without an adhesive resin. Shear bond strengths were measured and failure modes were evaluated. The incremental bond strength of silorane to the silorane-based composite was not significantly different from that of the methacrylate-based composite. However, repairing a silorane-based composite with a methacrylate-based composite significantly reduced the bond strength. Aelite showed a lower incremental bond strength than Z250 and silorane, but the use of an adhesive significantly improved the bond strength. The absence of an oxygen-inhibited layer did not affect the bond strength of the consecutive layers of the silorane-based composite. PMID:24807812

  9. Improved VSM for Incremental Text Classification

    NASA Astrophysics Data System (ADS)

    Yang, Zhen; Lei, Jianjun; Wang, Jian; Zhang, Xing; Guo, Jim

    2008-11-01

    As a simple classification method VSM has been widely applied in text information processing field. There are some problems for traditional VSM to select a refined vector model representation, which can make a good tradeoff between complexity and performance, especially for incremental text mining. To solve these problems, in this paper, several improvements, such as VSM based on improved TF, TFIDF and BM25, are discussed. And then maximum mutual information feature selection is introduced to achieve a low dimension VSM with less complexity, and at the same time keep an acceptable precision. The experimental results of spam filtering and short messages classification shows that the algorithm can achieve higher precision than existing algorithms under same conditions.

  10. An analytical theory of corona discharge plasmas

    SciTech Connect

    Uhm, H.S.; Lee, W.M.

    1997-09-01

    In this paper we describe an analytical investigation of corona discharge systems. Electrical charge and the energy transfer mechanism are investigated based on the circuit analysis. Efficient delivery of electrical energy from the external circuit to the reactor chamber is a major issue in design studies. The optimum condition obtained in this paper ensures 100{percent} energy transfer. Second-order coupled differential equations are numerically solved. All the analytical results agree remarkably well with numerical data. The reactor capacitor plays a pivotal role in circuit performance. The voltage profile is dominated by the reactor capacitor. Corona discharge properties in the reactor chamber are also investigated, assuming that a specified voltage profile V(t) is fed through the inner conductor. The analytical description is based on the electron moment equation. Defining the plasma breakdown parameter u=V/R{sub c}p, plasma is generated for a high-voltage pulse satisfying u{gt}u{sub c}, where u{sub c} is the critical breakdown parameter defined by geometrical configuration. Here, u is in units of a million volts per m per atm, and R{sub c} is the outer conductor radius. It is found that the plasma density profile generated inside the reactor chamber depends very sensitively on the system parameters. A small change of a physical parameter can easily lead to a density change in one order of magnitude.

  11. RADIATIVE HEATING OF THE SOLAR CORONA

    SciTech Connect

    Moran, Thomas G.

    2011-10-20

    We investigate the effect of solar visible and infrared radiation on electrons in the Sun's atmosphere using a Monte Carlo simulation of the wave-particle interaction and conclude that sunlight provides at least 40% and possibly all of the power required to heat the corona, with the exception of dense magnetic flux loops. The simulation uses a radiation waveform comprising 100 frequency components spanning the solar blackbody spectrum. Coronal electrons are heated in a stochastic manner by low coherence solar electromagnetic radiation. The wave 'coherence time' and 'coherence volume' for each component is determined from optical theory. The low coherence of solar radiation allows moving electrons to gain energy from the chaotic wave field which imparts multiple random velocity 'kicks' to these particles causing their velocity distribution to broaden or heat. Monte Carlo simulations of broadband solar radiative heating on ensembles of 1000 electrons show heating at per particle levels of 4.0 x 10{sup -21} to 4.0 x 10{sup -20} W, as compared with non-loop radiative loss rates of {approx}1 x 10{sup -20} W per electron. Since radiative losses comprise nearly all of the power losses in the corona, sunlight alone can explain the elevated temperatures in this region. The volume electron heating rate is proportional to density, and protons are assumed to be heated either by plasma waves or through collisions with electrons.

  12. The corona of HD 223460 (HR 9024)

    NASA Astrophysics Data System (ADS)

    Gondoin, P.

    2003-10-01

    HD 223460 (HR 9024), a chromospherically active late-type giant with a high X-ray luminosity, was observed by the XMM-Newton space observatory. Series of lines of highly ionized Fe and several Lyman lines of hydrogen-like ions and triplet lines of helium-like ions are visible in the reflection grating spectra, most notably from O and Ne. Analysis results suggest a scenario where the corona of HD 223460 is dominated by large magnetic structures similar in size to interconnecting loops between solar active regions but significantly hotter. The surface area coverage of these active regions may approach up to 30%. A hypothesis is that the interaction of these structures themselves induces a flaring activity on a small scale not visible in the EPIC light curves that is responsible for heating HD 223460 plasma to coronal temperatures of T >=107 K. The intense X-ray activity of HD 223460 is related to its evolutionary position at the bottom of the red giant branch. It is anticipated that its rotation will spin down in the future with the effect of decreasing its helicity-related, dynamo-driven activity and suppressing large-scale magnetic structures in its corona.

  13. Plasma Loops in the Solar Corona

    NASA Astrophysics Data System (ADS)

    Bray, R. J.; Cram, L. E.; Durrant, C.; Loughhead, R. E.

    1991-07-01

    A comprehensive account of the properties of plasma loops, the fundamental structural elements of the solar corona. Plasma loops cover a wide range of sizes and range in temperature from tens of thousands to millions of degrees. They not only define the structure of individual active regions but connect different active regions--even across the solar equator. Loops also play an integral and decisive role in the enormous solar explosions called flares. Over recent years a wealth of space and ground-based observations of loops has been obtained in various widely-spaced regions of the electromagnetic spectrum. In this book the authors have selected the best observational material from the literature on which to base a detailed account of the properties of flare and non-flare loops. The book also explores the larger implications of the loop structures for our understanding of solar and stellar coronae. The text is enhanced by a large number of illustrations and unique and beautiful photographs obtained from the ground and from space.

  14. Constraints on Lithospheric Rheology from Observations of Coronae on Venus

    NASA Astrophysics Data System (ADS)

    O'Rourke, Joseph G.; Smrekar, Suzanne; Moresi, Louis N.

    2016-10-01

    Coronae are enigmatic, quasi-circular features found in myriad geological environments. They are primarily distinguished as rings of concentric fractures superimposed on various topographic profiles with at least small-scale volcanism. Mantle plumes may produce coronae with interior rises, whereas coronae with central depressions are often attributed to downwellings like Rayleigh-Taylor instabilities. For almost three decades, modelers have attempted to reproduce the topographic and gravity profiles measured at coronae. Until recently, few studies also considered tectonic deformation and melt production. In particular, "Type 2" coronae have complete topographic rims but arcs of fractures extending less than 180°, signifying both brittle and ductile deformation. Only a narrow range of rheological parameters like temperature and volatile content may be compatible with these observations. Ultimately, identifying how lithospheric properties differ between Earth and Venus is critical to understanding what factors permit plate tectonics on rocky, Earth-sized planets.Here we present a hierarchical approach to study the formation of coronae. First, we discuss an observational survey enabled by a new digital elevation model derived from stereo topography for ~20% of the surface of Venus, which offers an order-of-magnitude improvement over the horizontal resolution (10 to 20 kilometers) of altimetry data from NASA's Magellan mission. Next, we search this new dataset for signs of lithospheric flexure around small coronae. Simple, thin-elastic plate models were fit to topographic profiles of larger coronae in previous studies, but data resolution impeded efforts to apply this method to the entire coronae population. Finally, we show simulations of the formation of coronae using Underworld II, an open-source code adaptable to a variety of geodynamical problems. We benchmark our code using models of pure Rayleigh-Taylor instabilities and then investigate the influence of

  15. Exploiting Outage and Error Probability of Cooperative Incremental Relaying in Underwater Wireless Sensor Networks

    PubMed Central

    Nasir, Hina; Javaid, Nadeem; Sher, Muhammad; Qasim, Umar; Khan, Zahoor Ali; Alrajeh, Nabil; Niaz, Iftikhar Azim

    2016-01-01

    This paper embeds a bi-fold contribution for Underwater Wireless Sensor Networks (UWSNs); performance analysis of incremental relaying in terms of outage and error probability, and based on the analysis proposition of two new cooperative routing protocols. Subject to the first contribution, a three step procedure is carried out; a system model is presented, the number of available relays are determined, and based on cooperative incremental retransmission methodology, closed-form expressions for outage and error probability are derived. Subject to the second contribution, Adaptive Cooperation in Energy (ACE) efficient depth based routing and Enhanced-ACE (E-ACE) are presented. In the proposed model, feedback mechanism indicates success or failure of data transmission. If direct transmission is successful, there is no need for relaying by cooperative relay nodes. In case of failure, all the available relays retransmit the data one by one till the desired signal quality is achieved at destination. Simulation results show that the ACE and E-ACE significantly improves network performance, i.e., throughput, when compared with other incremental relaying protocols like Cooperative Automatic Repeat reQuest (CARQ). E-ACE and ACE achieve 69% and 63% more throughput respectively as compared to CARQ in hard underwater environment. PMID:27420061

  16. Exploiting Outage and Error Probability of Cooperative Incremental Relaying in Underwater Wireless Sensor Networks.

    PubMed

    Nasir, Hina; Javaid, Nadeem; Sher, Muhammad; Qasim, Umar; Khan, Zahoor Ali; Alrajeh, Nabil; Niaz, Iftikhar Azim

    2016-01-01

    This paper embeds a bi-fold contribution for Underwater Wireless Sensor Networks (UWSNs); performance analysis of incremental relaying in terms of outage and error probability, and based on the analysis proposition of two new cooperative routing protocols. Subject to the first contribution, a three step procedure is carried out; a system model is presented, the number of available relays are determined, and based on cooperative incremental retransmission methodology, closed-form expressions for outage and error probability are derived. Subject to the second contribution, Adaptive Cooperation in Energy (ACE) efficient depth based routing and Enhanced-ACE (E-ACE) are presented. In the proposed model, feedback mechanism indicates success or failure of data transmission. If direct transmission is successful, there is no need for relaying by cooperative relay nodes. In case of failure, all the available relays retransmit the data one by one till the desired signal quality is achieved at destination. Simulation results show that the ACE and E-ACE significantly improves network performance, i.e., throughput, when compared with other incremental relaying protocols like Cooperative Automatic Repeat reQuest (CARQ). E-ACE and ACE achieve 69% and 63% more throughput respectively as compared to CARQ in hard underwater environment. PMID:27420061

  17. R Coronae Australis: A Cosmic Watercolour

    NASA Astrophysics Data System (ADS)

    2010-06-01

    This magnificent view of the region around the star R Coronae Australis was created from images taken with the Wide Field Imager (WFI) at ESO's La Silla Observatory in Chile. R Coronae Australis lies at the heart of a nearby star-forming region and is surrounded by a delicate bluish reflection nebula embedded in a huge dust cloud. The image reveals surprising new details in this dramatic area of sky. The star R Coronae Australis lies in one of the nearest and most spectacular star-forming regions. This portrait was taken by the Wide Field Imager (WFI) on the MPG/ESO 2.2-metre telescope at the La Silla Observatory in Chile. The image is a combination of twelve separate pictures taken through red, green and blue filters. This image shows a section of sky that spans roughly the width of the full Moon. This is equivalent to about four light-years at the distance of the nebula, which is located some 420 light-years away in the small constellation of Corona Australis (the Southern Crown). The complex is named after the star R Coronae Australis, which lies at the centre of the image. It is one of several stars in this region that belong to the class of very young stars that vary in brightness and are still surrounded by the clouds of gas and dust from which they formed. The intense radiation given off by these hot young stars interacts with the gas surrounding them and is either reflected or re-emitted at a different wavelength. These complex processes, determined by the physics of the interstellar medium and the properties of the stars, are responsible for the magnificent colours of nebulae. The light blue nebulosity seen in this picture is mostly due to the reflection of starlight off small dust particles. The young stars in the R Coronae Australis complex are similar in mass to the Sun and do not emit enough ultraviolet light to ionise a substantial fraction of the surrounding hydrogen. This means that the cloud does not glow with the characteristic red colour seen in

  18. Exploring dynamic events in the solar corona

    NASA Astrophysics Data System (ADS)

    Downs, Cooper James

    With the advent of modern computational technology it is now becoming the norm to employ detailed 3D computer models as empirical tools that directly account for the inhomogeneous nature of the Sun-Heliosphere environment. The key advantage of this approach lies in the ability to compare model results directly to observational data and to use a successful comparison (or lack thereof) to glean information on the underlying physical processes. Using extreme ultraviolet waves (EUV waves) as the overarching scientific driver, we apply this observation modeling approach to study the complex dynamics of the magnetic and thermodynamic structures that are observed in the low solar corona. Representing a highly non-trivial effort, this work includes three main scientific thrusts: an initial modeling effort and two EUV wave case-studies. First we document the development of the new Low Corona (LC) model, a 3D time-dependent thermodynamic magnetohydrodynamic (MHD) model implemented within the Space Weather Modeling Framework (SWMF). Observation synthesis methods are integrated within the LC model, which provides the ability to compare model results directly to EUV imaging observations taken by spacecraft. The new model is then used to explore the dynamic interplay between magnetic structures and thermodynamic energy balance in the corona that is caused by coronal heating mechanisms. With the model development complete, we investigate the nature of EUV waves in detail through two case-studies. Starting with the 2008 March 25 event, we conduct a series of numerical simulations that independently vary fundamental parameters thought to govern the physical mechanisms behind EUV waves. Through the subsequent analysis of the 3D data and comparison to observations we find evidence for both wave and non-wave mechanisms contributing to the EUV wave signal. We conclude with a comprehensive observation and modeling analysis of the 2010 June 13 EUV wave event, which was observed by the

  19. Validation of daily increments in otoliths of northern squawfish larvae

    USGS Publications Warehouse

    Wertheimer, R.H.; Barfoot, C.A.

    1998-01-01

    Otoliths from laboratory-reared northern squawfish, Ptychocheilus oregonensis, larvae were examined to determine the periodicity of increment deposition. Increment deposition began in both sagittae and lapilli after hatching. Reader counts indicated that increment formation was daily in sagittae of 1-29-day-old larvae. However, increment counts from lapilli were significantly less than the known ages of northern squawfish larvae, possibly because some increments were not detectable. Otolith readability and age agreement among readers were greatest for young (<11 days) northern squawfish larvae. This was primarily because a transitional zone of low-contrast material began forming in otoliths of 8-11-day-old larvae and persisted until approximately 20 days after hatching. Formation of the transition zone appeared to coincide with the onset of exogenous feeding and continued through yolk sac absorption. Our results indicate that aging wild-caught northern squawfish larvae using daily otolith increment counts is possible.

  20. Corona Formation on Venus Via Extension and Lithospheric Instability

    NASA Astrophysics Data System (ADS)

    Piskorz, D.; Elkins-Tanton, L. T.; Smrekar, S. E.

    2014-12-01

    Given the absence of plate tectonics on Venus, the origin of major rift systems like Parga Chasma is unclear. As Venus and Earth have similar radii and radiogenic abundances, we assume they have a similar internal structure and composition. Venus does not appear to have plate tectonics, and its surface displays a range of volcanic and tectonic features, including those that are both similar and dissimilar to those on Earth. In order to understand how Venus loses its heat, we study coronae at Parga Chasma. There are over 500 quasi-circular volcano-tectonic features called coronae on Venus, 131 of which are associated with Parga Chasma. Are these coronae important in the formation of the rift, or vice versa? How do they contribute to planetary heat loss? Coronae are believed to form via small-scale mantle upwellings, lithospheric instability, or a combination thereof. However, the genetic link between the coronae and rifts has remained unclear. By drawing an analogy to the East African Rift, we propose a mechanism for the formation of off-rift coronae due to the rifting process. We model the interaction of a rising mantle plume associated with a rift with a preexisting layer of dense material at the lithosphere-mantle boundary and show that a rift and its associated off-rift coronae may be genetically linked. We calculate the resulting surface topographies, melt volumes, and Bouguer gravity anomalies and find a correlation to observations.

  1. Charging of moving surfaces by corona discharges sustained in air

    SciTech Connect

    Wang, Jun-Chieh Kushner, Mark J.; Zhang, Daihua; Leoni, Napoleon Birecki, Henryk Gila, Omer

    2014-07-28

    Atmospheric pressure corona discharges are used in electrophotographic (EP) printing technologies for charging imaging surfaces such as photoconductors. A typical corona discharge consists of a wire (or wire array) biased with a few hundred volts of dc plus a few kV of ac voltage. An electric discharge is produced around the corona wire from which electrons drift towards and charge the underlying dielectric surface. The surface charging reduces the voltage drop across the gap between the corona wire and the dielectric surface, which then terminates the discharge, as in a dielectric barrier discharge. In printing applications, this underlying surface is continuously moving throughout the charging process. For example, previously charged surfaces, which had reduced the local electric field and terminated the local discharge, are translated out of the field of view and are replaced with uncharged surface. The uncharged surface produces a rebound in the electric field in the vicinity of the corona wire which in turn results in re-ignition of the discharge. The discharge, so reignited, is then asymmetric. We found that in the idealized corona charging system we investigated, a negatively dc biased corona blade with a dielectric covered ground electrode, the discharge is initially sustained by electron impact ionization from the bulk plasma and then dominated by ionization from sheath accelerated secondary electrons. Depending on the speed of the underlying surface, the periodic re-ignition of the discharge can produce an oscillatory charging pattern on the moving surface.

  2. The photosphere-corona Interface: enrichement of the corona in low FIP elements and helium shells

    NASA Astrophysics Data System (ADS)

    Bazin, C.; Koutchmy, S.; Lamy, P.; Veselovski, I.

    2014-12-01

    Slitless consecutive spectra were obtained during the contacts of the last total solar eclipses (2008, 2009, 2010, 2012, et 2013). They allowed to show that the overabundance of low First Ionisation Potential (FIP) elements (Fe II, Ti II, Ba II) in the corona comes from the low layers of the solar atmosphere, just near and above the temperature minimum region of the high photosphere. All spectra are recorded with a fast CCD/CMOS camera, with an equivalent radial resolution of 60 milliarcseconds, or 45 km in the solar atmosphere, above a solar edge not affected by the parasitic light like it is outside of total eclipse conditions. Many emission lines of low FIP elements appear in regions situated between 200 to 600 km above the solar limb defined by the true continuum measured between the lines. This continuum appears at these altitudes where the beta of the plasma is near 1. The He I 4713 Å and He II 4686 Å (Paschen alpha line) shells appear at the height of 800 km above the solar edge and higher. The light curve I = f(h) of each ion is located at a particuliar altitude in the solar atmosphere. The scale height corresponds to a density variation, which allows to evaluate the temperature thanks to the hydrostatic equilibrium assumption. Moreover, with ionised Titanium lines taken as markers, we show a similarity between the photosphere-corona interface and the prominence-corona interface. We discuss the role of the magnetic field and the ambipolar diffusion for supplying the corona in mass, without taking into account the role of spicules. The photo-ionisation of the helium lines by the EUV coronal lines is illustrated thanks to an extract of SDO/AIA coronal stacked image simultaneously obtained.

  3. An Experimental Study of Incremental Surface Loading of an Elastic Plate: Application to Volcano Tectonics

    NASA Technical Reports Server (NTRS)

    Williams, K. K.; Zuber, M. T.

    1995-01-01

    Models of surface fractures due to volcanic loading an elastic plate are commonly used to constrain thickness of planetary lithospheres, but discrepancies exist in predictions of the style of initial failure and in the nature of subsequent fracture evolution. In this study, we perform an experiment to determine the mode of initial failure due to the incremental addition of a conical load to the surface of an elastic plate and compare the location of initial failure with that predicted by elastic theory. In all experiments, the mode of initial failure was tension cracking at the surface of the plate, with cracks oriented circumferential to the load. The cracks nucleated at a distance from load center that corresponds the maximum radial stress predicted by analytical solutions, so a tensile failure criterion is appropriate for predictions of initial failure. With continued loading of the plate, migration of tensional cracks was observed. In the same azimuthal direction as the initial crack, subsequent cracks formed at a smaller radial distance than the initial crack. When forming in a different azimuthal direction, the subsequent cracks formed at a distance greater than the radial distance of the initial crack. The observed fracture pattern may explain the distribution of extensional structures in annular bands around many large scale, circular volcanic features.

  4. Chemical Compositions and Anomalies in Stellar Coronae

    NASA Technical Reports Server (NTRS)

    Drake, Jeremy; Oliversen, Ronald J. (Technical Monitor)

    2005-01-01

    In summary, as the papers cited here and in earlier reports demonstrate, this award has enabled us to obtain a fairly good picture of the abundance anomalies in stellar coronae. The "inverse FIP" effect in very active stars has now been fleshed out as a more complex anomaly depending on FIP, whereas before it appeared only in terms of a general metal paucity, the recent solar abundance assessment of Asplund et a1 will, if correct, challenge some of the older interpretations of coronal abundance anomalies since they imply quite different relative abundances of CNO compared with Fe, Mg and Si. Further investigations have been in into the possibility of modeling some of the recent coronal abundance anomaly results in terms of Alfven wave-driven separation of neutrals and ions in the upper chromosphere. This work still remains in the seed stage, and future funding from a different program will be requested to pursue it further.

  5. The TESIS experiment on the CORONAS-PHOTON spacecraft

    NASA Astrophysics Data System (ADS)

    Kuzin, S. V.; Zhitnik, I. A.; Shestov, S. V.; Bogachev, S. A.; Bugaenko, O. I.; Ignat'ev, A. P.; Pertsov, A. A.; Ulyanov, A. S.; Reva, A. A.; Slemzin, V. A.; Sukhodrev, N. K.; Ivanov, Yu. S.; Goncharov, L. A.; Mitrofanov, A. V.; Popov, S. G.; Shergina, T. A.; Solov'ev, V. A.; Oparin, S. N.; Zykov, A. M.

    2011-04-01

    On February 26, 2009, the first data was obtained in the TESIS experiment on the research of the solar corona using imaging spectroscopy. The TESIS is a part of the scientific equipment of the CORONAS-PHO-TON spacecraft and is designed for imaging the solar corona in soft X-ray and extreme ultraviolet regions of the spectrum with high spatial, spectral, and temporal resolutions at altitudes from the transition region to three solar radii. The article describes the main characteristics of the instrumentation, management features, and operation modes.

  6. Formation of Coronae Structures on Venus by Thermochemical Diapirs

    NASA Astrophysics Data System (ADS)

    Golabek, G. J.; Kaus, B. J. P.; Tackley, P. J.

    2009-04-01

    One of the most prominent features on the surface of Venus are the coronae. They are large scale volcano-tectonic structures, which are approximately circular with a mean diameter of 200 - 300 km [Dombard et al., 2007], with extrema ranging from 60 km to about 2000 km diameter. A total of 515 coronae were found on Venus in the Magellan data [Stofan et al., 2001]. The intruiging point about corona is that there is no counterpart on the other terrestrial planets for these structures. Nine different groups of coronae have been observed on Venus [Smrekar and Stofan, 1997]. Smrekar and Stofan [1997] suggested that these different groups can stand for different steps in the time evolution of coronae. Several mechanisms have been proposed to explain their formation: Dombard et al. [2007] suggested that coronae form in response to magmatic loading of the crust over zones of partial melting above thermally buoyant heads of transient mantle plumes that impinge on the base of the thermal lithosphere. On the other side, the potential importance of crust delamination induced by mantle upwellings as formation mechanisms for coronae was pointed out by Smrekar and Stofan [1997]. Here, we present results on coronae formation using the recently developed 2D finite element code MILAMIN_VEP, which employs MILAMIN technology [Dabrowski et al., 2008]. We apply a temperature and stress-dependent visco-elasto-plastic rheology in a rectangular box, which includes a rising thermochemical diapir beneath the Venusian crust and lithosphere. The rheological parameters are taken from results inferred for Venusian materials [Mackwell et al., 1998]. A free surface is used in our calculations, which allows for the self-consistent computation of topography induced by the buoyant diapir. A hybrid particle-in-cell approach allows remeshing of strongly deformed grid cells. A systematic investigation of the physical conditions under which coronae can form is being performed in 2D. Initial results

  7. Magnetic Relaxation in the Solar Corona

    NASA Astrophysics Data System (ADS)

    Miller, Kenneth; Fornberg, Bengt; Flyer, Natasha; Low, B. C.

    2009-01-01

    This is a mathematical study of the long-lived hydromagnetic structures produced in the tenuous solar corona by the turbulent, resistive relaxation of a magnetic field under the condition of extremely high electrical conductivity. The relaxation theory of Taylor, originally developed for a laboratory device, is extended to treat the open atmosphere where the relaxing field must interact with its surrounding fields. A boundary-value problem is posed for a two-dimensional model that idealizes the corona as the half Cartesian plane filled with a potential field (1) that is anchored to a rigid, perfectly conducting base and (2) that embeds a force-free magnetic field in the form of a flux-rope oriented horizontally and perpendicular to the Cartesian plane. The flux-rope has a free boundary, which is an unknown in the construction of a solution for this atmosphere. Pairs of magnetostatic solutions are constructed to represent the initial and final states of a flux-rope relaxation that conserve both the total magnetic helicity and total axial magnetic flux, using a numerical iterative method specially developed for this study. The collection of numerical solutions found provides an insight into the interplay among several hydromagnetic properties in the formation of long-lived coronal structures. In particular, the study shows (1) that the outward spread of reconnection between a relaxing flux-rope and its external field may be arrested at some outer magnetic flux surface within which a constant-α force-free field emerges as the minimum-energy state and (2) that this outward spread is complicated by an inward, partial collapse of the relaxing flux-rope produced by a loss of internal magnetic pressure.

  8. Freon destruction in a nanosecond corona discharge

    SciTech Connect

    Akhmedzhanov, R.A.; Vikharev, A.L.; Gorbachev, A.M.

    1995-12-31

    One of the main reasons for destruction of the ozone layer is high content of freon in the Earth atmosphere. The life time of chlorofluorocarbons (CFC) in the stratosphere is tens of years, therefore, along with abandonment of the use of CFC compositions. of importance is the search for efficient ways to purify both industrial gaseous wastes and the atmosphere proper from pollution. Among various purification methods the most promising seems to be the method based on freon destruction during processes of dissociative electron attachment. Freon molecules in this case are destroyed selectively mainly at the stage of plasma decay by cold electrons, for which the constant of dissociative attachment is especially high (k{sub a} = 10{sup -7} - 10{sup -9}cm{sup 3}/s). By that, as the source of electrons we propose using nanosecond discharges with a high level of the reduced electric field, E/N, when the main share of the pulse energy goes into ionization, and gas heating is insignificant. These requirements are best met by the use of barrier and pulse corona discharge, which are widely employed for ozone generation and purification of gaseous wastes. Plasma of such discharges is composed of chaotically arising nanosecond microdischarges. The possibility to purify atmosphere from freons directly by means of a nanosecond microwave discharge produced the troposphere by ground-based sources is also studied. An important problem for the said applications, along with estimation of efficiency of freon destruction is determination of chemical composition of the products that appear at the post-discharge stage as the result of plasma chemical reaction. This presentation gives results of experimental studies of freon destruction in a pulse-periodic nanosecond corona discharge.

  9. Untwisting magnetic fields in the solar corona

    NASA Astrophysics Data System (ADS)

    Bhattacharyya, Ramit; Smolarkiewicz, Piotr; Chye Low, Boon

    2012-07-01

    The solar corona is the tenuous atmosphere of the Sun characterized by a temperature of the order of million degrees Kelvin, an ambient magnetic field of 10 to 15 Gauss and a very high magnetic Reynolds number because of which it qualifies as a near-ideal magnetofluid system. It is well known that for such a system, the magnetic flux across every fluid surface remains effectively constant to a good approximation. Under this so called ``frozen-in'' condition then, it is possible to partition this magnetofluid into contiguous magnetic subvolumes each entrapping its own subsystem of magnetic flux. Thin magnetic flux tubes are an elementary example of such magnetic subvolumes evolving in time with no exchange of fluid among them. The internal twists and interweaving of these flux tubes, collectively referred as the magnetic topology, remains conserved under the frozen-in condition. Because of the dynamical evolution of the magnetofluid, two such subvolumes can come into direct contact with each other by expelling a third interstitial subvolume. In this process, the magnetic field may become discontinuous across the surface of contact by forming a current sheet there. Because of the small spatial scales generated by steepening of magnetic field gradient, the otherwise negligible resistivity becomes dominant and allows for reconnection of field lines which converts magnetic energy into heat. This phenomenon of spontaneous current sheet formation and its subsequent resistive decay is believed to be a possible mechanism for heating the solar corona to its million degree Kelvin temperature. In this work the dynamics of spontaneous current sheet formation is explored through numerical simulations and the results are presented.

  10. Coronae of Stars with Supersolar Elemental Abundances

    NASA Technical Reports Server (NTRS)

    Peretz, Uria; Behar, Ehud; Drake, Stephen A.

    2015-01-01

    Coronal elemental abundances are known to deviate from the photospheric values of their parent star, with the degree of deviation depending on the first ionization potential (FIP). This study focuses on the coronal composition of stars with supersolar photospheric abundances. We present the coronal abundances of six such stars: 11 LMi, iota Hor, HR 7291, tau Boo, and alpha Cen A and B. These stars all have high-statistics X-ray spectra, three of which are presented for the first time. The abundances we measured were obtained using the line-resolved spectra of the Reflection Grating Spectrometer (RGS) in conjunction with the higher throughput EPIC-pn camera spectra onboard the XMM-Newton observatory. A collisionally ionized plasma model with two or three temperature components is found to represent the spectra well. All elements are found to be consistently depleted in the coronae compared to their respective photospheres. For 11 LMi and tau Boo no FIP effect is present, while iota Hor, HR 7291, and alpha Cen A and B show a clear FIP trend. These conclusions hold whether the comparison is made with solar abundances or the individual stellar abundances. Unlike the solar corona, where low-FIP elements are enriched, in these stars the FIP effect is consistently due to a depletion of high-FIP elements with respect to actual photospheric abundances. A comparison with solar (instead of stellar) abundances yields the same fractionation trend as on the Sun. In both cases, a similar FIP bias is inferred, but different fractionation mechanisms need to be invoked.

  11. Recoupling pulse sequences with constant phase increments

    NASA Astrophysics Data System (ADS)

    Khaneja, Navin; Kumar, Ashutosh

    2016-10-01

    The paper studies a family of recoupling pulse sequences in magic angle spinning (MAS) solid state NMR, that are characterized by constant phase increments at regular intervals. These pulse sequences can be employed for both homonuclear and heteronuclear recoupling experiments and are robust to dispersion in chemical shifts and rf-inhomogeneity. The homonuclear pulse sequence consists of a building block (2 π) ϕp , where ϕp =p (n - 1) π/n, where n is number of blocks in a rotor period and p = 0, 1, 2, … . The pulse sequence repeats itself every rotor period when n is odd and every two rotor period when n is even. The heteronuclear recoupling pulse sequence consists of a building block (2 π) ϕ1p and (2 π) ϕ2p on channel I and S, where ϕ1p = p (2 n - 3) π/2 n, ϕ2p = p (2 n - 1) π/2 n and n is number of blocks in a rotor period. The recoupling pulse sequences mix the z magnetization. Experimental quantification of this method is shown for 13Cα -13CO , homonuclear recoupling in a sample of Glycine and 15N -13Cα , heteronuclear recoupling in Alanine. Application of this method is demonstrated on a sample of tripeptide N-formyl-[U-13C ,15N ]- Met-Leu-Phe-OH (MLF).

  12. Recoupling pulse sequences with constant phase increments.

    PubMed

    Khaneja, Navin; Kumar, Ashutosh

    2016-10-01

    The paper studies a family of recoupling pulse sequences in magic angle spinning (MAS) solid state NMR, that are characterized by constant phase increments at regular intervals. These pulse sequences can be employed for both homonuclear and heteronuclear recoupling experiments and are robust to dispersion in chemical shifts and rf-inhomogeneity. The homonuclear pulse sequence consists of a building block [Formula: see text] , where ϕ(p)=p(n-1)πn, where n is number of blocks in a rotor period and p=0,1,2,…. The pulse sequence repeats itself every rotor period when n is odd and every two rotor period when n is even. The heteronuclear recoupling pulse sequence consists of a building block [Formula: see text] and [Formula: see text] on channel I and S, where ϕ1(p)=p(2n-3)π2n,ϕ2(p)=p(2n-1)π2n and n is number of blocks in a rotor period. The recoupling pulse sequences mix the z magnetization. Experimental quantification of this method is shown for (13)Cα-(13)CO, homonuclear recoupling in a sample of Glycine and (15)N-(13)Cα, heteronuclear recoupling in Alanine. Application of this method is demonstrated on a sample of tripeptide N-formyl-[U-(13)C,(15)N]- Met-Leu-Phe-OH (MLF). PMID:27569693

  13. Incremental fusion of partial biometric information

    NASA Astrophysics Data System (ADS)

    Abboud, Ali J.; Jassim, Sabah A.

    2012-06-01

    Existing face recognition schemes are mostly based on extracting biometric feature vectors either from whole face images, or from a fixed facial region (e.g., eyes, nose, and mouth). Extreme variation in quality conditions between biometric enrolment and verification stages badly affects the performance of face recognition systems. Such problems have partly motivated several investigations into the use of partial facial features for face recognition. Nevertheless, partial face recognition is potentially useful in several applications, for instance, it used in forensics for detectives to identify individuals after some accidents such as fire or explosion. In this paper, we propose a scheme to fuse the biometric information of partial face images incrementally based on their recognition accuracy (or discriminative power) ranks. Such fusion scheme uses the optimal ratio of full/partial face images in each different quality condition. We found that such scheme is also useful for full face images to enhance authentication accuracy significantly. Nevertheless, it reduces the required storage requirements and processing time of the biometric system. Our experiments show that the required ratio of full/partial facial images to achieve optimal performance varies from (5%) to (80%) according to the quality conditions whereas the authentication accuracy improves significantly for low quality biometric samples.

  14. Evolution of cooperation driven by incremental learning

    NASA Astrophysics Data System (ADS)

    Li, Pei; Duan, Haibin

    2015-02-01

    It has been shown that the details of microscopic rules in structured populations can have a crucial impact on the ultimate outcome in evolutionary games. So alternative formulations of strategies and their revision processes exploring how strategies are actually adopted and spread within the interaction network need to be studied. In the present work, we formulate the strategy update rule as an incremental learning process, wherein knowledge is refreshed according to one's own experience learned from the past (self-learning) and that gained from social interaction (social-learning). More precisely, we propose a continuous version of strategy update rules, by introducing the willingness to cooperate W, to better capture the flexibility of decision making behavior. Importantly, the newly gained knowledge including self-learning and social learning is weighted by the parameter ω, establishing a strategy update rule involving innovative element. Moreover, we quantify the macroscopic features of the emerging patterns to inspect the underlying mechanisms of the evolutionary process using six cluster characteristics. In order to further support our results, we examine the time evolution course for these characteristics. Our results might provide insights for understanding cooperative behaviors and have several important implications for understanding how individuals adjust their strategies under real-life conditions.

  15. Comparison of Topographic Profiles Across Venus' Coronae and Craters: Implications for Corona Origin Hypothesis

    NASA Astrophysics Data System (ADS)

    Stoddard, P. R.; Jurdy, D. M.

    2006-12-01

    Venus' surface hosts nearly 1000 unambiguous impact craters, ranging in diameter from 1.5 to 280 km. Although the majority of these are pristine, slightly less than 200 have been modified by either volcanic or tectonic activity or both. In addition, numerous researchers have identified hundreds of ring-like features of varying morphology, termed "coronae." These have typically been thought of as having a diapiric or volcanic origin. Recently, however, based on the circular to quasi-circular nature of coronae, an alternative origin - impact - has been proposed. We compare the profiles across agreed-upon craters to several coronae that have been suggested as impact sites. For each feature, 36 profiles (taken every ten degrees) are aligned and then averaged together. For Mead, Cleopatra, Meitner, and Isabella craters, the profiles display the typical rim and basin structure expected for craters, but for Klenova crater the average is more domal, with only a few of the individual profiles looking crater-like. Among the "contested" coronae, the average profiles for Eurynome, Maya, and C21 appear crater-like, albeit with more variation among the individual profiles than seen in the agreed-upon craters. Anquet has a rim-and-basin structure, but unlike typical craters, the basin is elevated above the surrounding plains. Acrea appears to be a small hill in a large depression, again with a high degree of variability among the profiles. Ninhursag is clearly domal, and cannot be taken as a crater. A summary of the variability of the profiles - where 100% correlation would indicate perfect circular symmetry - indicates that, with the exception of Klenova, those features universally agreed-upon as craters have the highest correlation percentages - all at or above 80%. The disputed features are not as circular, although C21 is close. Based on this analysis, we conclude that Klenova has been mischaracterized as an impact crater, and that C21 and some other features previously

  16. On the transition from stable positive glow corona to streamers

    NASA Astrophysics Data System (ADS)

    Liu, Lipeng; Becerra, Marley

    2016-06-01

    A 2D numerical simulation of the transition from stable positive glow corona to streamers in coaxial cylindrical configuration is presented. The hydrodynamic model with several convection-dominated continuity equations together with Poisson equation are solved with consideration of the ionization layer. The transition from a stable positive glow corona produced under a DC voltage to streamers is investigated under a sudden change of the applied voltage. The critical rate of rise of voltage required for the transition from positive glow to streamer corona is evaluated with a voltage ramp. By introducing either physical or numerical instabilities into the model, streamers with filamentary structures are observed, which produce a sudden increase of the discharge current by more than two orders of magnitude. It is also found that the surface electric field of the corona-generating conductor deviates from the onset electric field, casting doubts about the validity of Kaptzov’s approximation to evaluate the transition from stable glow to streamers.

  17. Viscoelastic Relaxation of Topographic Highs on Venus to Produce Coronae

    NASA Technical Reports Server (NTRS)

    Janes, Daniel M.; Squyres, Steven W.

    1995-01-01

    Coronae on Venus are believed to result from the gravitationally driven relaxation of topography that was originally raised by mantle diapirs. We examine this relaxation using a viscoelastic finite element code, and show that an initially plateau shaped load will evolve to the characteristic corona topography of central raised bowl, annular rim, and surrounding moat. Stresses induced by the relaxation are consistent with the development of concentric extensional fracturing common on the outer margins of corona moats. However, relaxation is not expected to produce the concentric faulting often observed on the annular rim. The relaxation timescale is shorter than the diapir cooling timescale, so loss of thermal support controls the rate at which topography is reduced. The final corona shape is supported by buoyancy and flexural stresses and will persist through geologic time. Development of lower, flatter central bowls and narrower and more pronounced annular rims and moats enhanced by thicker crusts, higher thermal gradients, and crustal thinning over the diapir.

  18. A Data-Driven Evolution Model for the Global Corona

    NASA Astrophysics Data System (ADS)

    Feng, X. S.; Jiang, C.; Xiang, C. Q.; Wu, S.

    2011-12-01

    In this work we have developed a new time-dependent global corona model for the study of dynamic evolution of the global corona that can respond continuously to the changing of the photospheric magnetogram. A surface flux transport (SFT) model is employed to produce the time-varying and self-consistent magnetogram with synoptic map as input. The global corona model is established with our newly-developed numerical code AMR-CESE-MHD on an overset grid of Yin-Yang overlapping structure. The SFT model and the three-dimensional global corona model is coupled through the boundary condition of projected-characteristic method. Numerical study of the coronal evolution from Carrington rotation 1913 to 1915 presents results comparable with multi-observed coronal images.

  19. Scintillation effects on radio wave propagation through solar corona

    NASA Technical Reports Server (NTRS)

    Ho, C. M.; Sue, M. K.; Bedrossian, A.; Sniffin, R. W.

    2002-01-01

    When RF waves pass through the solar corona and solar wind regions close to the Sun, strong scintillation effects appear at their amplitude, frequency and phase, especially in the regions very close to the Sun (less than 4 solar radius).

  20. Study of the solar corona using radio and space observations

    NASA Technical Reports Server (NTRS)

    Dulk, G. A.

    1984-01-01

    The physics of coronal transients, the characteristics of radiation and accelerated particles at the time of flares, and the density/temperature structure of the transition region and corona and the coronal magnetic field are investigated.

  1. Simulation of RF coronas using the FE-FCT method.

    PubMed

    Georghiou, G E; Metaxas, A C

    2000-01-01

    The precursor of arcs in radio frequency heating systems, namely corona discharges, are examined numerically in this paper, using the finite element-flux corrected transport technique. A point-plane configuration is used as a first approximation for a radio frequency applicator and the effects of the operating frequency and pressure on the current output, charge densities, corona onset voltage and light output are investigated. It was found that an increase in the operating frequency around the radio frequency part of the spectrum, resulted in an increase in the corona onset voltage, which accounts for the less arc-prone behavior of microwave systems. Also, a decrease in the pressure resulted in a reduction of the corona onset voltage, and thus the increased possibility of arc formation in radio frequency systems operating under vacuum conditions.

  2. Experimental Tools to Study Molecular Recognition within the Nanoparticle Corona

    PubMed Central

    Landry, Markita P.; Kruss, Sebastian; Nelson, Justin T.; Bisker, Gili; Iverson, Nicole M.; Reuel, Nigel F.; Strano, Michael S.

    2014-01-01

    Advancements in optical nanosensor development have enabled the design of sensors using syntheticmolecular recognition elements through a recently developed method called Corona Phase MolecularRecognition (CoPhMoRe). The synthetic sensors resulting from these design principles are highly selective for specific analytes, and demonstrate remarkable stability for use under a variety of conditions. An essential element of nanosensor development hinges on the ability to understand the interface between nanoparticles and the associated corona phase surrounding the nanosensor, an environment outside of the range of traditional characterization tools, such as NMR. This review discusses the need for new strategies and instrumentation to study the nanoparticle corona, operating in both in vitro and in vivo environments. Approaches to instrumentation must have the capacity to concurrently monitor nanosensor operation and the molecular changes in the corona phase. A detailed overview of new tools for the understanding of CoPhMoRe mechanisms is provided for future applications. PMID:25184487

  3. Transmission line corona losses under hoar frost conditions

    SciTech Connect

    Lahti, K.; Nousiainen, K.; Lahtinen, M.

    1997-04-01

    Transmission line corona losses under hoar frost conditions were studied in the climate room of the high voltage laboratory of Tampere University of Technology. The measurements were performed using a coaxial measurement arrangement with different bundle and conductor types. The effects of conductor and bundle type, temperature, applied voltage and hoar frost thickness on corona losses were investigated. A two-conductor bundle had corona losses about 2.5--5 times higher than a three-conductor bundle. Relatively thin hoar frosts were used in the tests. Even the thinnest hoar frost resulted in remarkable corona losses and the losses were very sensitive to changes in the hoar frost thickness. The ambient temperature had a strong influence on the measured losses.

  4. Decomposition characteristics of toluene by a corona radical shower system.

    PubMed

    Wu, Zu-liang; Gao, Xiang; Luo, Zhong-yang; Ni, Ming-jiang; Cen, Ke-fa

    2004-01-01

    Non-thermal plasma technologies offer an innovative approach to decomposing various volatile organic compounds(VOCs). The decomposition of toluene from simulated flue gas was investigated using a pipe electrode with nozzles for the generation of free radicals. Corona characteristics and decomposition of toluene were investigated experimentally. In addition, the decomposition mechanism of toluene was explored in view of reaction rate. The experimental results showed that the humidity of additional gas has an important effect on corona characteristics and modes and stable streamer corona can be generated through optimizing flow rate and humidity of additional gas. Applied voltage, concentration of toluene, humidity of toluene and resident time are some important factors affecting decomposition efficiency. Under optimizing conditions, the decomposition efficiency of toluene can reach 80%. These results can give a conclusion that the corona radical shower technology is feasible and effective on the removal of toluene in the flue gas.

  5. Incremental Seismic Rehabilitation of School Buildings (K-12).

    ERIC Educational Resources Information Center

    Krimgold, Frederick; Hattis, David; Green, Melvyn

    Asserting that the strategy of incremental seismic rehabilitation makes it possible for schools to get started now on improving earthquake safety, this manual provides school administrators with the information necessary to assess the seismic vulnerability of their buildings and to implement a program of incremental seismic rehabilitation for…

  6. Testicular failure

    MedlinePlus

    ... LH . Your doctor may also order a semen analysis to examine the number of healthy sperm you are producing. Sometimes, an ultrasound of the testes will be ordered. Testicular failure and low testosterone level may be hard to ...

  7. Miniature Dual-Corona Ionizer for Bipolar Charging of Aerosol

    PubMed Central

    Qi, Chaolong; Kulkarni, Pramod

    2015-01-01

    A corona-based bipolar charger has been developed for use in compact, field-portable mobility size spectrometers. The charger employs an aerosol flow cavity exposed to two corona ionizers producing ions of opposite polarity. Each corona ionizer houses two electrodes in parallel needle-mesh configuration and is operated at the same magnitude of corona current. Experimental measurement of detailed charge distribution of near-monodisperse particles of different diameter in the submicrometer size range showed that the charger is capable of producing well-defined, consistent bipolar charge distributions for flow rates up to 1.5 L/min and aerosol concentration up to 107 per cm3. For particles with preexisting charge of +1, 0, and −1, the measured charge distributions agreed well with the theoretical distributions within the range of experimental and theoretical uncertainties. The transmission efficiency of the charger was measured to be 80% for 10 nm particles (at 0.3 L/min and 5 μA corona current) and increased with increasing diameter beyond this size. Measurement of uncharged fractions at various combinations of positive and negative corona currents showed the charger performance to be insensitive to fluctuations in corona current. Ion concentrations under positive and negative unipolar operation were estimated to be 8.2 × 107 and 3.37 × 108 cm−3 for positive and negative ions; the n·t product value under positive corona operation was independently estimated to be 8.5 × 105 s/cm3. The ion concentration estimates indicate the charger to be capable of “neutralizing” typical atmospheric and industrial aerosols in most measurement applications. The miniature size, simple and robust operation makes the charger suitable for portable mobility spectrometers. PMID:26512158

  8. Time-dependent tomographic reconstruction of the solar corona

    NASA Astrophysics Data System (ADS)

    Vibert, D.; Peillon, C.; Lamy, P.; Frazin, R. A.; Wojak, J.

    2016-10-01

    Solar rotational tomography (SRT) applied to white-light coronal images observed at multiple aspect angles has been the preferred approach for determining the three-dimensional (3D) electron density structure of the solar corona. However, it is seriously hampered by the restrictive assumption that the corona is time-invariant which introduces significant errors in the reconstruction. We first explore several methods to mitigate the temporal variation of the corona by decoupling the "fast-varying" inner corona from the "slow-moving" outer corona using multiple masking (either by juxtaposition or recursive combination) and radial weighting. Weighting with a radial exponential profile provides some improvement over a classical reconstruction but only beyond ≈ 3R⊙. We next consider a full time-dependent tomographic reconstruction involving spatio-temporal regularization and further introduce a co-rotating regularization aimed at preventing concentration of reconstructed density in the plane of the sky. Crucial to testing our procedure and properly tuning the regularization parameters is the introduction of a time-dependent MHD model of the corona based on observed magnetograms to build a time-series of synthetic images of the corona. Our procedure, which successfully reproduces the time-varying model corona, is finally applied to a set of 53 LASCO-C2 pB images roughly evenly spaced in time from 15 to 29 March 2009. Our procedure paves the way to a time-dependent tomographic reconstruction of the coronal electron density to the whole set of LASCO-C2 images presently spanning 20 years.

  9. LSH-RANSAC: Incremental Matching of Large-Size Maps

    NASA Astrophysics Data System (ADS)

    Tanaka, Kanji; Saeki, Ken-Ichi; Minami, Mamoru; Ueda, Takeshi

    This paper presents a novel approach for robot localization using landmark maps. With recent progress in SLAM researches, it has become crucial for a robot to obtain and use large-size maps that are incrementally built by other mapper robots. Our localization approach successfully works with such incremental and large-size maps. In literature, RANSAC map-matching has been a promising approach for large-size maps. We extend the RANSAC map-matching so as to deal with incremental maps. We combine the incremental RANSAC with an incremental LSH database and develop a hybrid of the position-based and the appearance-based approaches. A series of experiments using radish dataset show promising results.

  10. Elastic Thickness Estimates for Coronae Associated with Chasmata on Venus

    NASA Technical Reports Server (NTRS)

    Hoogenboom, T.; Martin, P.; Housean, G. A.

    2005-01-01

    Coronae are large-scale circular tectonic features surrounded by annular ridges. They are generally considered unique to Venus and may offer insights into the differences in lithospheric structure or mantle convective pattern between Venus and Earth. 68% of all coronae are associated with chasmata or fracture belts. The remaining 32% are located at volcanic rises or in the plains. Chasmata are linear to arcuate troughs, with trough parallel fractures and faults which extend for 1000 s of kilometers. Estimates of the elastic thickness of the lithosphere (T(sub e)) have been calculated in a number of gravity/topography studies of Venus and for coronae specifically. None of these studies, however, have explored the dependence of T(sub e) on the tectonic history of the region, as implied from the interpretation of relative timing relationships between coronae and surrounding features. We examine the relationship between the local T(sub e) and the relative ages of coronae and chasmata with the aim of further constraining the origin and evolution of coronae and chasmata systems.

  11. Direct observation of a single nanoparticle-ubiquitin corona formation

    NASA Astrophysics Data System (ADS)

    Ding, Feng; Radic, Slaven; Chen, Ran; Chen, Pengyu; Geitner, Nicholas K.; Brown, Jared M.; Ke, Pu Chun

    2013-09-01

    The advancement of nanomedicine and the increasing applications of nanoparticles in consumer products have led to administered biological exposure and unintentional environmental accumulation of nanoparticles, causing concerns over the biocompatibility and sustainability of nanotechnology. Upon entering physiological environments, nanoparticles readily assume the form of a nanoparticle-protein corona that dictates their biological identity. Consequently, understanding the structure and dynamics of a nanoparticle-protein corona is essential for predicting the fate, transport, and toxicity of nanomaterials in living systems and for enabling the vast applications of nanomedicine. Here we combined multiscale molecular dynamics simulations and complementary experiments to characterize the silver nanoparticle-ubiquitin corona formation. Notably, ubiquitins competed with citrates for the nanoparticle surface, governed by specific electrostatic interactions. Under a high protein/nanoparticle stoichiometry, ubiquitins formed a multi-layer corona on the particle surface. The binding exhibited an unusual stretched-exponential behavior, suggesting a rich binding kinetics. Furthermore, the binding destabilized the α-helices while increasing the β-sheet content of the proteins. This study revealed the atomic and molecular details of the structural and dynamic characteristics of nanoparticle-protein corona formation.The advancement of nanomedicine and the increasing applications of nanoparticles in consumer products have led to administered biological exposure and unintentional environmental accumulation of nanoparticles, causing concerns over the biocompatibility and sustainability of nanotechnology. Upon entering physiological environments, nanoparticles readily assume the form of a nanoparticle-protein corona that dictates their biological identity. Consequently, understanding the structure and dynamics of a nanoparticle-protein corona is essential for predicting the fate

  12. Titan's corona: The contribution of exothermic chemistry

    NASA Astrophysics Data System (ADS)

    De La Haye, V.; Waite, J. H.; Cravens, T. E.; Nagy, A. F.; Johnson, R. E.; Lebonnois, S.; Robertson, I. P.

    2007-11-01

    The contribution of exothermic ion and neutral chemistry to Titan's corona is studied. The production rates for fast neutrals N 2, CH 4, H, H 2, 3CH 2, CH 3, C 2H 4, C 2H 5, C 2H 6, N( 4S), NH, and HCN are determined using a coupled ion and neutral model of Titan's upper atmosphere. After production, the formation of the suprathermal particles is modeled using a two-stream simulation, as they travel simultaneously through a thermal mixture of N 2, CH 4, and H 2. The resulting suprathermal fluxes, hot density profiles, and energy distributions are compared to the N 2 and CH 4 INMS exospheric data presented in [De La Haye, V., Waite Jr., J.H., Johnson, R.E., Yelle, R.V., Cravens, T.E., Luhmann, J.G., Kasprzak, W.T., Gell, D.A., Magee, B., Leblanc, F., Michael, M., Jurac, S., Robertson, I.P., 2007. J. Geophys. Res., doi:10.1029/2006JA012222, in press], and are found insufficient for producing the suprathermal populations measured. Global losses of nitrogen atoms and carbon atoms in all forms due to exothermic chemistry are estimated to be 8.3×10 Ns and 7.2×10 Cs.

  13. Measuring the Electron Temperature in the Corona

    NASA Technical Reports Server (NTRS)

    Davila, Joseph; SaintCyr, Orville C.; Reginald, Nelson

    2008-01-01

    We report on an experiment to demonstrate the feasibility of a new method to obtain the electron temperature and flow speed in the solar corona by observing the visible Kcoronal spectrum during the total solar eclipse on 29 March 2006 in Libya. Results show that this new method is indeed feasible, giving electron temperatures and speeds of 1.10 $\\pm$ 0.05 MK, 103.0 $\\pm$ 92.0 $kmsA{-l}$; 0.98 $\\pm$ 0.12 MK, 0.0 + 10.0 $kmsA{-1)s; 0.70 $\\pm$ 0.08 MK, 0.0 + 10.0 $kmsA{-l)$ at l.l{\\it R)$ {\\odot}$ in the solar north, east and west, respectively, and 0.93 $\\pm$ 0.12 MK, 0.0 + 10.0 $kmsA{-l}$ at 1.2{\\it R}$ {\\odot}$ in the solar east. This new technique could be easily used from a space-based platform in a coronagraph to produce two dimensional maps of the electron temperature and bulk flow speed at the base of the solar wind useful for the study of heliospheric structure and space weather.

  14. Indirect detection of the Martian helium corona

    NASA Astrophysics Data System (ADS)

    Barabash, S.; Norberg, O.

    1994-07-01

    The ion composition mass spectrometer ASPERA on board the PHOBOS 2 spacecraft detected particles with M/q = 4 in the vicinity of Mars. A significant difference between the measured particle velocity and the solar wind velocity suggests that these ions are of planetary origin, apparently He(+) from ionisation within the Martian helium corona. The particles had typical energies of either more than 10 keV or about 500 eV. The former correspond to ion pickup in the solar wind and the latter might be ions extracted from the upper ionosphere by an electric field. The observed density of pickup He(+) ions was 0.02-0.1/cc and the He(+) density in the plasmasheet was of 0.2-0.7/cc. According to a recent model of the Martian neutral atmosphere (Moroz et al, 1991) the He(+) density could reach 0.2/cc at the Phobos orbit. Such values give mass densities comparable to those of the solar wind. Thus, helium may play a role in the solar wind mass loading process near Mars.

  15. The theory of positive glow corona

    NASA Astrophysics Data System (ADS)

    Morrow, R.

    1997-11-01

    A theory for the current and light pulses of positive glow corona from a point in air is presented; this phenomenon was first observed as an apparently continuous glow by Michael Faraday. Results are obtained, in concentric sphere geometry, for air at atmospheric pressure, by solving the continuity equations for electrons, positive ions, negative ions and metastable oxygen molecules, coupled with Poisson's equation. A series of `saw-toothed' current pulses of period about 0022-3727/30/22/008/img1 is predicted with a DC current level. Accompanying the current peaks are discrete pulses of light 30 ns wide. Successive `shells' of positive ions, from successive current pulses, carry 96% of the mean current. The mean current - voltage relationship has the classic square-law form. The seed electrons required for successive pulses are detached from negative ions by metastable oxygen molecules. Photo-ionization is crucial for the discharge at the anode and for the formation of negative ions throughout the gap. The pulse frequency varies with applied voltage and is found to be approximately proportional to the positive-ion mobility. The surface electric field at the central electrode remains close to Peek's onset field. The origin of onset streamers is explained and sub-microsecond voltage pulses are found to produce streamers. The results for concentric-cylinder electrodes are described briefly.

  16. Detection of increments in noise intensity by monkeys.

    PubMed

    Clopton, B M

    1972-05-01

    Monkeys were trained to detect 100-msec increments in the intensity of continuous white noise. A response on one of two bars was reinforced with some probability if it conformed to the presence or absence of the increment on that trial. Stimulus parameters of background intensity, increment size, and probability of increment presentation were varied, and response probabilities and latencies were recorded. The task was analogous to the "yes-no" task used in human psychophysics. Data analysis within the context of signal-detection theory revealed response biasing toward one bar or the other to be related to the probability of increment presentation, whereas sensitivity depended on the combination of increment size and background noise intensity. Weber's law was found to hold for a large range of background intensities in that the sensitivity to relative intensity increments varied little. Performance was compared to that of an ideal observer that uses samples of the envelope of the noise waveform on which to base its responses.

  17. Development of Efficient Models of Corona Discharges Around Tall Structures

    NASA Astrophysics Data System (ADS)

    Tucker, J.; Pasko, V. P.

    2012-12-01

    This work concerns with numerical modeling of glow corona and sreamer corona discharges that occur near tall ground structures under thunderstorm conditions. Glow corona can occur when ambient electric field reaches modest values on the order of 0.2 kV/cm and when the electric field near sharp points of ground structure rises above a geometry dependent critical field required for ionization of air. Air is continuously ionized in a small region close to the surface of the structure and ions diffuse out into the surrounding air forming a corona. A downward leader approaching from a thundercloud causes a further increase in the electric field at the ground level. If the electric field rises to the point where it can support formation of streamers in air surrounding the tall structure, a streamer corona flash, or series of streamer corona flashes can be formed significantly affecting the space charge configuration formed by the preceding glow corona. The streamer corona can heat the surrounding air enough to form a self-propagating thermalized leader that is launched upward from the tall structure. This leader travels upward towards the thundercloud and connects with the downward approaching leader thus causing a lightning flash. Accurate time-dependent modeling of charge configuration created by the glow and streamer corona discharges around tall structure is an important component for understanding of the sequence of events leading to lightning attachment to the tall structure. The present work builds on principal modeling ideas developed previously in [Aleksandrov et al., J. Phys. D: Appl. Phys., 38, 1225, 2005; Bazelyan et al., Plasma Sources Sci. Technol., 17, 024015, 2008; Kowalski, E. J., Honors Thesis, Penn State Univ., University Park, PA, May 2008; Tucker and Pasko, NSF EE REU Penn State Annual Res. J., 10, 13, 2012]. The non-stationary glow and streamer coronas are modeled in spherical geometry up to the point of initiation of the upward leader. The model

  18. MAGNETIC STRUCTURE OF RAPIDLY ROTATING FK COMAE-TYPE CORONAE

    SciTech Connect

    Cohen, O.; Drake, J. J.; Kashyap, V. L.; Korhonen, H.; Elstner, D.; Gombosi, T. I.

    2010-08-10

    We present a three-dimensional simulation of the corona of an FK Com-type rapidly rotating G giant using a magnetohydrodynamic model that was originally developed for the solar corona in order to capture the more realistic, non-potential coronal structure. We drive the simulation with surface maps for the radial magnetic field obtained from a stellar dynamo model of the FK Com system. This enables us to obtain the coronal structure for different field topologies representing different periods of time. We find that the corona of such an FK Com-like star, including the large-scale coronal loops, is dominated by a strong toroidal component of the magnetic field. This is a result of part of the field being dragged by the radial outflow, while the other part remains attached to the rapidly rotating stellar surface. This tangling of the magnetic field, in addition to a reduction in the radial flow component, leads to a flattening of the gas density profile with distance in the inner part of the corona. The three-dimensional simulation provides a global view of the coronal structure. Some aspects of the results, such as the toroidal wrapping of the magnetic field, should also be applicable to coronae on fast rotators in general, which our study shows can be considerably different from the well-studied and well-observed solar corona. Studying the global structure of such coronae should also lead to a better understanding of their related stellar processes, such as flares and coronal mass ejections, and in particular should lead to an improved understanding of mass and angular momentum loss from such systems.

  19. VIEWCACHE: An incremental database access method for autonomous interoperable databases

    NASA Technical Reports Server (NTRS)

    Roussopoulos, Nick; Sellis, Timoleon

    1991-01-01

    The objective is to illustrate the concept of incremental access to distributed databases. An experimental database management system, ADMS, which has been developed at the University of Maryland, in College Park, uses VIEWCACHE, a database access method based on incremental search. VIEWCACHE is a pointer-based access method that provides a uniform interface for accessing distributed databases and catalogues. The compactness of the pointer structures formed during database browsing and the incremental access method allow the user to search and do inter-database cross-referencing with no actual data movement between database sites. Once the search is complete, the set of collected pointers pointing to the desired data are dereferenced.

  20. Heart failure.

    PubMed

    2014-12-15

    Essential facts Heart failure affects about 900,000 people in the UK. The condition can affect people of all ages, but it is more common in older people, with more than half of all patients over the age of 75. It is caused by the heart failing to pump enough blood around the body at the right pressure, usually because the heart muscle has become too weak or stiff to work properly. Acute heart failure, which occurs when symptoms develop quickly, is the leading cause of hospital admission in people over 65. PMID:25492766

  1. Effects of superimposed electrical stimulation on perceived discomfort and torque increment size and variability.

    PubMed

    Miller, Michael; Downham, David; Lexell, Jan

    2003-01-01

    Superimposed electrical stimulation techniques can be used to detect central activation failure (CAF), that is, incomplete central nervous system recruitment or suboptimal activation of motor units. The purpose of this study was to evaluate the effects of two stimulation parameters on perceived discomfort and torque increment size and variability. Discomfort was evaluated using a visual analog scale (0-100 mm) for pain. The rectus femoris muscle of the dominant leg of 24 young healthy men was stimulated during submaximal (80% maximal) voluntary contractions. The size and variability of torque increments and perceived discomfort were assessed following stimulation with: (1) pulse trains (100 HZ, 150 V, 0.2-ms pulse duration) of different lengths (50 ms and 100 ms); and (2) pulse trains (100 HZ, 100 ms, 150 V) with different pulse durations (0.2 ms and 0.1 ms). Pulse trains of 100 ms generated larger torque increments and produced less variability, but caused more discomfort than pulse trains of 50 ms. Average discomfort ratings for pulse trains of 100 ms were 43.1 mm, and of 50 ms were 53.2 mm. There was no difference in torque increment size or in variability between pulse trains with pulse durations of 0.1 ms and 0.2 ms, whereas discomfort was less for the shorter pulse durations; average discomfort ratings were 53.1 mm and 58.1 mm for pulse durations of 0.1 ms and 0.2 ms, respectively. Thus, the appropriate selection of stimulation parameters can reduce discomfort but maintain the ability to detect CAF.

  2. Protein corona formation for nanomaterials and proteins of a similar size: hard or soft corona?

    PubMed

    Liu, Wei; Rose, Jérôme; Plantevin, Sophie; Auffan, Mélanie; Bottero, Jean-Yves; Vidaud, Claude

    2013-02-21

    Nanoparticles (NPs) entering a biological fluid undergo surface modification due to dynamic, physicochemical interactions with biological components, especially proteins. In this work we used complementary bio-physico-chemical approaches to characterize the effects of interactions between CeO(2) NPs, immunoglobulins (IgGs) and bovine serum albumin (BSA) of a similar size on protein structural evolution as well as formation of (hetero-) aggregates. Using circular dichroism we showed that IgGs and BSA underwent significant structural changes after interaction with NPs. The NPs and protein-NPs were observed after size exclusion chromatography, highlighting the fact that few aggregates were stable enough to pass this mild separation step. X-ray absorption spectroscopy suggested that the surface chemistry of NPs was not affected by these proteins, also implying weak interactions. Competitive experiments revealed that, while the serum was more concentrated for BSA, IgG-NP aggregates were more stable. Altogether, our results indicate that, under our experimental conditions, the formation of a "protein corona" is an unstable and reversible mechanism. This indicates that, when NPs and proteins are similar in size, the adsorption concept (i.e. protein corona concept) cannot be applied to model the NP-protein interaction, and a heteroaggregation model is more appropriate.

  3. Heart Failure

    MedlinePlus

    ... of breath Common causes of heart failure are coronary artery disease, high blood pressure and diabetes. It is more common in people who are 65 years old or older, African Americans, people who are ... treatments fail. NIH: National Heart, Lung, and Blood Institute

  4. Nitrogen oxides removal by pulsed corona enhanced wet electrostatics precipitation

    SciTech Connect

    Tseng, C.H.; Keener, T.C.; Khang, S.J.

    1999-07-01

    This paper presents the results of a bench-scale pulsed-corona enhanced wet electrostatic precipitator (wESP) application for removal of nitrogen oxides. This wESP is designed to operate wet/dry, positive/negative, and pulsed/non-pulsed conditions. The applied pulsed voltage is varied from 0 to 60 kV at 70 Hz. Gas flow rate is a nominal 7 m{sup 3}/hr and the collecting electrode area is 0.20 m{sup 2}. A simulated flue gas with NO concentration up to 1,200 ppm{sub v} has been used to determine the feasibility of NO{sub x} removal in the wESP. NO has to be oxidized to N{sub 2} before any removal takes place. NO{sub x} removal efficiency increased with gas residence time, inlet NO concentration and applied corona power. In the air stream with 10 seconds gas residence time, up to 20% of 1,000 ppm NO (or 22% NO{sub x}) was removed from an air stream of 1.9x10{sup {minus}3} m{sup 3}/s with a water flow of 6.3 x 10{sup {minus}5} m{sup 3}/sec and 20 W, 70 Hz pulsed corona. Both ammonia and ozone injections improve the NO{sub x} removal for both the corona and non-corona cases. With the inclusion of NH{sub 3} (NH{sub 3}/NO{sub x} ratio 1.3) and 25 watts corona power, NO removal efficiency was increased from 28% to 57%. The amount of in-situ ozone is not enough to be considered as a major NO{sub x} removal mechanism in this wESP. However, the additional injection of ozone improves the NO removal from 29% to 38% for both the corona and non-corona cases. When the oxygen concentration is dropped to 3% in a simulated flue gas with 12% CO{sub 2} and 800 ppm NO and 70% relative humidity at 11.5 s of gas residence time, the removal efficiency of NO is only 5%. Adding NH{sub 3} (NH{sub 3}/NO{sub x} ratio 1) at 76 watts corona power, NO removal is increased to 13%.

  5. 48 CFR 3432.771 - Provision for incremental funding.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... funding. 3432.771 Section 3432.771 Federal Acquisition Regulations System DEPARTMENT OF EDUCATION ACQUISITION REGULATION GENERAL CONTRACTING REQUIREMENTS CONTRACT FINANCING Contract Funding 3432.771 Provision for incremental funding. The contracting officer shall insert the provision in...

  6. Monitoring Holes in the Sun's Corona

    NASA Astrophysics Data System (ADS)

    Kohler, Susanna

    2016-09-01

    Coronal holes are where the fast solar wind streams out of the Suns atmosphere, sending charged particles on rapid trajectories out into the solar system. A new study examines how the distribution of coronal holes has changed over the last 40 years.Coronal holes form where magnetic field lines open into space (B) instead of looping back to the solar surface (A). [Sebman81]Source of the Fast Solar WindAs a part of the Suns natural activity cycle, extremely low-density regions sometimes form in the solar corona. These coronal holes manifest themselves as dark patches in X-ray and extreme ultraviolet imaging, since the corona is much hotter than the solar surface that peeks through from underneath it.Coronal holes form when magnetic field lines open into space instead of looping back to the solar surface. In these regions, the solar atmosphere escapes via these field lines, rapidly streaming away from the Suns surface in whats known as the fast solar wind.Coronal Holes Over Space and TimeAutomated detection of coronal holes from image-based analysis is notoriously difficult. Recently, a team of scientists led by Kenichi Fujiki (ISEE, Nagoya University, Japan) has developed an automated prediction technique for coronal holes that relies instead on magnetic-field data for the Sun, obtained at the National Solar Observatorys Kitt Peak between 1975 and 2014. The team used these data to produce a database of 3335 coronal hole predictions over nearly 40 years.Latitude distribution of 2870 coronal holes (each marked by an x; color indicates polarity), overlaid on the magnetic butterfly map of the Sun. The low-latitude coronal holes display a similar butterfly pattern, in which they move closer to the equator over the course of the solar cycle. Polar coronal holes are more frequent during solar minima. [Fujiki et al. 2016]Examining trends in the coronal holes distribution in latitude and time, Fujiki and collaborators find a strong correlation between the total area covered

  7. Low-frequency heliographic observations of the quiet Sun corona

    NASA Astrophysics Data System (ADS)

    Stanislavsky, A. A.; Koval, A. A.; Konovalenko, A. A.

    2013-12-01

    We present new results of heliographic observations of quiet-Sun radio emission fulfilled by the UTR-2 radio telescope. The solar corona investigations have been made close to the last solar minimum (Cycle 23) in the late August and early September of 2010 by means of the two-dimensional heliograph within 16.5-33 MHz. Moreover, the UTR-2 radio telescope was used also as an 1-D heliograph for one-dimensional scanning of the Sun at the beginning of September 2010 as well as in short-time observational campaigns in April and August of 2012. The average values of integral flux density of the undisturbed Sun continuum emission at different frequencies have been found. Using the data, we have determined the spectral index of quiet-Sun radio emission in the range 16.5-200 MHz. It is equal to -2.1±0.1. The brightness distribution maps of outer solar corona at frequencies 20.0 MHz and 26.0 MHz have been obtained. The angular sizes of radio Sun were estimated. It is found that the solar corona at these frequencies is stretched-out along equatorial direction. The coefficient of corona ellipticity varies slightly during above period. Its mean magnitudes are equal to ≈ 0.75 and ≈ 0.73 at 20.0 MHz and 26.0 MHz, respectively. The presented results for continuum emission of solar corona conform with being ones at higher frequencies.

  8. Modeling the multi-ion structure of the solar corona

    NASA Astrophysics Data System (ADS)

    Ofman, Leon; Provornikova, Elena; Wang, Tongjiang

    2014-06-01

    The solar corona is typically observed in EUV by SDO/AIA and other instruments using the heavy ion emission lines such as Fe IX, Fe XII, and other ion emission lines. However, the relative (to protons) abundance of the emitting ions is very low and the collisional coupling between the Fe ions and electrons decreases rapidly with height in the low corona, while gravitational settling may become significant in quiescent long-lived magnetic structures, such as streamers. Thus, the structure of the weakly collisional solar corona imaged in Fe IX (and other heavy ions) may differ significantly from the structure of the main electron-proton constituents of the corona. The electron structure is observed by white light coronagraphs, and during solar eclipses in the low corona. I present the results of multi-fluid modeling of coronal streamers and other magnetic structures that demonstrate the effects of weak coupling between the heavy ions and the coronal electron-proton components, and show that the multi-ion coronal structure must be taken into account in interpretation of EUV observations.

  9. Oxidative coupling of methane with ac and dc corona discharges

    SciTech Connect

    Liu, C.; Marafee, A.; Hill, B.; Xu, G.; Mallinson, R.; Lobban, L.

    1996-10-01

    The oxidative coupling of methane (OCM) is being actively studied for the production of higher hydrocarbons from natural gas. The present study concentrated on the oxidative conversion of methane in an atmospheric pressure, nonthermal plasma formed by ac or dc corona discharges. Methyl radicals are formed by reaction with negatively-charged oxygen species created in the corona discharge. The selectivity to products ethane and ethylene is affected by electrode polarity, frequency, and oxygen partial pressure in the feed. Higher C{sub 2} yields were obtained with the ac corona. All the ac corona discharges are initiated at room temperature (i.e., no oven or other heat source is used), and the temperature increases to 300--500 C due to the exothermic reactions and the discharge itself. The largest C{sub 2} yield is 21% with 43.3% methane conversion and 48.3% C{sub 2} selectivity at a flowrate of 100 cm{sup 3}/min when the ac corona is at 30 Hz, 5 kV (rms) input power was used. The methane conversion may be improved to more than 50% by increasing the residence time, but the C{sub 2} selectivity decreases. A reaction mechanism including the oxidative dehydrogenation (OXD) of ethane to ethylene is presented to explain the observed phenomena. The results suggest that ac and/or dc gas discharge techniques have significant promise for improving the economics of OCM processes.

  10. CORONA DISCHARGE IGNITION FOR ADVANCED STATIONARY NATURAL GAS ENGINES

    SciTech Connect

    Dr. Paul D. Ronney

    2003-09-12

    An ignition source was constructed that is capable of producing a pulsed corona discharge for the purpose of igniting mixtures in a test chamber. This corona generator is adaptable for use as the ignition source for one cylinder on a test engine. The first tests were performed in a cylindrical shaped chamber to study the characteristics of the corona and analyze various electrode geometries. Next a test chamber was constructed that closely represented the dimensions of the combustion chamber of the test engine at USC. Combustion tests were performed in this chamber and various electrode diameters and geometries were tested. The data acquisition and control system hardware for the USC engine lab was updated with new equipment. New software was also developed to perform the engine control and data acquisition functions. Work is underway to design a corona electrode that will fit in the new test engine and be capable igniting the mixture in one cylinder at first and eventually in all four cylinders. A test engine was purchased for the project that has two spark plug ports per cylinder. With this configuration it will be possible to switch between corona ignition and conventional spark plug ignition without making any mechanical modifications.

  11. INTERCHANGE RECONNECTION IN A TURBULENT CORONA

    SciTech Connect

    Rappazzo, A. F.; Matthaeus, W. H.; Ruffolo, D.; Servidio, S.; Velli, M.

    2012-10-10

    Magnetic reconnection at the interface between coronal holes and loops, the so-called interchange reconnection, can release the hotter, denser plasma from magnetically confined regions into the heliosphere, contributing to the formation of the highly variable slow solar wind. The interchange process is often thought to develop at the apex of streamers or pseudo-streamers, near Y- and X-type neutral points, but slow streams with loop composition have been recently observed along fanlike open field lines adjacent to closed regions, far from the apex. However, coronal heating models, with magnetic field lines shuffled by convective motions, show that reconnection can occur continuously in unipolar magnetic field regions with no neutral points: photospheric motions induce a magnetohydrodynamic turbulent cascade in the coronal field that creates the necessary small scales, where a sheared magnetic field component orthogonal to the strong axial field is created locally and can reconnect. We propose that a similar mechanism operates near and around boundaries between open and closed regions inducing a continual stochastic rearrangement of connectivity. We examine a reduced magnetohydrodynamic model of a simplified interface region between open and closed corona threaded by a strong unipolar magnetic field. This boundary is not stationary, becomes fractal, and field lines change connectivity continuously, becoming alternatively open and closed. This model suggests that slow wind may originate everywhere along loop-coronal-hole boundary regions and can account naturally and simply for outflows at and adjacent to such boundaries and for the observed diffusion of slow wind around the heliospheric current sheet.

  12. Discovering New R Coronae Borealis Stars

    NASA Astrophysics Data System (ADS)

    Clayton, Geoffrey C.; Tisserand, Patrick; Welch, Douglas L.; LeBleu, Amy

    2016-01-01

    The R Coronae Borealis (RCB) stars are rare hydrogen-deficient, carbon-rich supergiants. Two evolutionary scenarios have been suggested, a double degenerate merger of two white dwarfs, or a final helium shell flash in a PN central star. The evidence pointing toward a white-dwarf merger or a final-flash origin for RCB stars is contradictory. The distribution on the sky and radial velocities of the RCB stars tend toward those of the bulge population but a much larger sample of stars is needed to determine the true population. We need to discover RCB stars much more efficiently. In order to do this, we have used a series of IR color-color cuts, using the recent release of the WISE All-Sky Catalog, to produce a sample of 2200 candidates that may yield over 200 new RCB star identifications. Most of these candidates do not have lightcurves, the traditional technique of identifying RCB stars from their characteristic large and irregular light variations. We have obtained optical spectra of several hundred candidates and have confirmed over 40 new RCB stars in the Galaxy. We are attempting to develop a quantitative spectral classification system for the RCB stars so that they can be identified without an accompanying light curve. The cooler RCB stars look like carbon stars with strong C2 bands, but they can be differentiated from carbon stars by their extreme hydrogen deficiency and very low 13C/12C ratio. Also, the red CN bands are much weaker in RCB stars than in carbon stars. The number of RCB stars in the Galaxy may be consistent with the predicted number of He/CO white-dwarf mergers. Solving the mystery of how the RCB stars evolve would be a watershed event in the study of stellar evolution that will lead to a better understanding of other important types of stellar merger events such as Type Ia SNe.

  13. Interchange Reconnection in a Turbulent Corona

    NASA Astrophysics Data System (ADS)

    Rappazzo, A. F.; Matthaeus, W. H.; Ruffolo, D.; Servidio, S.; Velli, M.

    2012-10-01

    Magnetic reconnection at the interface between coronal holes and loops, the so-called interchange reconnection, can release the hotter, denser plasma from magnetically confined regions into the heliosphere, contributing to the formation of the highly variable slow solar wind. The interchange process is often thought to develop at the apex of streamers or pseudo-streamers, near Y- and X-type neutral points, but slow streams with loop composition have been recently observed along fanlike open field lines adjacent to closed regions, far from the apex. However, coronal heating models, with magnetic field lines shuffled by convective motions, show that reconnection can occur continuously in unipolar magnetic field regions with no neutral points: photospheric motions induce a magnetohydrodynamic turbulent cascade in the coronal field that creates the necessary small scales, where a sheared magnetic field component orthogonal to the strong axial field is created locally and can reconnect. We propose that a similar mechanism operates near and around boundaries between open and closed regions inducing a continual stochastic rearrangement of connectivity. We examine a reduced magnetohydrodynamic model of a simplified interface region between open and closed corona threaded by a strong unipolar magnetic field. This boundary is not stationary, becomes fractal, and field lines change connectivity continuously, becoming alternatively open and closed. This model suggests that slow wind may originate everywhere along loop-coronal-hole boundary regions and can account naturally and simply for outflows at and adjacent to such boundaries and for the observed diffusion of slow wind around the heliospheric current sheet.

  14. Interchange Reconnection in a Turbulent Corona

    NASA Astrophysics Data System (ADS)

    Rappazzo, A. F.; Matthaeus, W. H.; Ruffolo, D. J.; Servidio, S.; Velli, M. M.

    2012-12-01

    Magnetic reconnection at the interface between coronal holes and loops, so-called interchange reconnection, can release the hotter, denser plasma from magnetically confined regions into the heliosphere, contributing to the formation of the highly variable slow solar wind. In the prevailing ``standard'' view the interchange process is thought to develop in null points (with B=0) preferably at the apex of streamers or pseudo-streamers, near Y and X-points, from where slow solar wind flows would originate. This standard model does not meet recent observations of slow wind streams from the edges of active regions, that suggest that slow streams are not limited to apex-regions near neutral points (B=0). Furthermore in order to account for the slow wind diffusion (~ 30 degrees) observed in situ around the Heliospheric Current Sheet, within the standard model framework one has to posit that the slow wind would originate from a small fraction, with a complex topology, of the whole coronal hole-loop boundary, namely narrow channels (supposedly at observationally sub-resolution scales) linking coronal holes. However, coronal heating models, with magnetic field lines shuffled by convective motions, show that reconnection can occur continuously in unipolar magnetic field regions with no neutral points. We propose that a similar alternate interchange mechanism operating near boundaries between open and closed regions induces a continual stochastic rearrangement of connectivity everywhere along the open-closed boundary. We examine a reduced magnetohydrodynamic model of a simplified unipolar interface region between open and closed corona. This boundary is not stationary, becomes fractal, and field lines change connectivity continuously, becoming alternatively open and closed. This model suggests that slow wind may originate everywhere along coronal loop-hole boundaries, a possibility that has major implications for coronal heating and models of the slow solar wind, and accounts

  15. 26 CFR 1.41-8 - Alternative incremental credit.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ....41-8T(b)(5) as contained in 26 CFR part 1, revised April 1, 2006. Paragraphs (b)(3) and (b)(4)(ii) of... 26 Internal Revenue 1 2010-04-01 2010-04-01 true Alternative incremental credit. 1.41-8 Section 1... Credits Against Tax § 1.41-8 Alternative incremental credit. (a) Determination of credit. At the...

  16. 26 CFR 1.41-8 - Alternative incremental credit.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ....41-8T(b)(5) as contained in 26 CFR part 1, revised April 1, 2006. Paragraphs (b)(3) and (b)(4)(ii) of... 26 Internal Revenue 1 2011-04-01 2009-04-01 true Alternative incremental credit. 1.41-8 Section 1... Credits Against Tax § 1.41-8 Alternative incremental credit. (a) Determination of credit. At the...

  17. An incremental clustering algorithm based on Mahalanobis distance

    NASA Astrophysics Data System (ADS)

    Aik, Lim Eng; Choon, Tan Wee

    2014-12-01

    Classical fuzzy c-means clustering algorithm is insufficient to cluster non-spherical or elliptical distributed datasets. The paper replaces classical fuzzy c-means clustering euclidean distance with Mahalanobis distance. It applies Mahalanobis distance to incremental learning for its merits. A Mahalanobis distance based fuzzy incremental clustering learning algorithm is proposed. Experimental results show the algorithm is an effective remedy for the defect in fuzzy c-means algorithm but also increase training accuracy.

  18. Entity versus incremental theories predict older adults' memory performance.

    PubMed

    Plaks, Jason E; Chasteen, Alison L

    2013-12-01

    The authors examined whether older adults' implicit theories regarding the modifiability of memory in particular (Studies 1 and 3) and abilities in general (Study 2) would predict memory performance. In Study 1, individual differences in older adults' endorsement of the "entity theory" (a belief that one's ability is fixed) or "incremental theory" (a belief that one's ability is malleable) of memory were measured using a version of the Implicit Theories Measure (Dweck, 1999). Memory performance was assessed with a free-recall task. Results indicated that the higher the endorsement of the incremental theory, the better the free recall. In Study 2, older and younger adults' theories were measured using a more general version of the Implicit Theories Measure that focused on the modifiability of abilities in general. Again, for older adults, the higher the incremental endorsement, the better the free recall. Moreover, as predicted, implicit theories did not predict younger adults' memory performance. In Study 3, participants read mock news articles reporting evidence in favor of either the entity or incremental theory. Those in the incremental condition outperformed those in the entity condition on reading span and free-recall tasks. These effects were mediated by pretask worry such that, for those in the entity condition, higher worry was associated with lower performance. Taken together, these studies suggest that variation in entity versus incremental endorsement represents a key predictor of older adults' memory performance. PMID:24128076

  19. Entity versus incremental theories predict older adults' memory performance.

    PubMed

    Plaks, Jason E; Chasteen, Alison L

    2013-12-01

    The authors examined whether older adults' implicit theories regarding the modifiability of memory in particular (Studies 1 and 3) and abilities in general (Study 2) would predict memory performance. In Study 1, individual differences in older adults' endorsement of the "entity theory" (a belief that one's ability is fixed) or "incremental theory" (a belief that one's ability is malleable) of memory were measured using a version of the Implicit Theories Measure (Dweck, 1999). Memory performance was assessed with a free-recall task. Results indicated that the higher the endorsement of the incremental theory, the better the free recall. In Study 2, older and younger adults' theories were measured using a more general version of the Implicit Theories Measure that focused on the modifiability of abilities in general. Again, for older adults, the higher the incremental endorsement, the better the free recall. Moreover, as predicted, implicit theories did not predict younger adults' memory performance. In Study 3, participants read mock news articles reporting evidence in favor of either the entity or incremental theory. Those in the incremental condition outperformed those in the entity condition on reading span and free-recall tasks. These effects were mediated by pretask worry such that, for those in the entity condition, higher worry was associated with lower performance. Taken together, these studies suggest that variation in entity versus incremental endorsement represents a key predictor of older adults' memory performance.

  20. Admittance Survey of Type 1 Coronae on Venus: Implications for Elastic Thickness

    NASA Technical Reports Server (NTRS)

    Hoogenboom, T.; Smrekar, S. E.; Anderson, F. S.; Houseman, G.

    2003-01-01

    Coronae are volcano-tectonic features on Venus which range from 60km to 2600km and are defined by their nearly circular patterns of fractures. Type 1 (regular) coronae are classified as having >50% complete fracture annuli. Previous work has examined the factors controlling the morphology, size, and fracture pattern of coronae, using lithospheric properties, loading signature and geologic characteristics. However, these studies have been limited to Type 2 (topographic) coronae (e.g. coronaes with <50% fracture annuli), and the factors controlling the formation of Type 1 coronae remain poorly understood. In this study, we apply the methodology of to survey the admittance signature for Type 1 coronae to determine the controlling parameters which govern Type 1 coronae formation.

  1. Comparison of direct current and 50 Hz alternating current microscopic corona characteristics on conductors

    SciTech Connect

    Zhang, Shuai Zhang, Bo He, Jinliang

    2014-06-15

    Corona discharge is one of the major design factors for extra-high voltage and ultra-high voltage DC/AC transmission lines. Under different voltages, corona discharge reveals different characteristics. This paper aims at investigating DC and AC coronas on the microscopic scale. To obtain the specific characteristics of DC and AC coronas, a new measurement approach that utilizes a coaxial wire-cylinder corona cage is designed in this paper, and wires of different diameters are used in the experiment. Based on the measurements, the respective microscopic characteristics of DC and AC coronas are analyzed and compared. With differences in characteristics between DC and AC coronas proposed, this study provides useful insights into DC/AC corona discharges on transmission line applications.

  2. Alfvenically driven slow shocks in the solar chromosphere and corona

    NASA Technical Reports Server (NTRS)

    Hollweg, Joseph V.

    1992-01-01

    The nonlinear evolution of an Alfvenic impulse launched from the photosphere and its dynamical effects on the chromosphere, transition region (TR), and corona are investigated using a simple 1D model. It is found that the leading edge of the torsional pulse can steepen into a fast shock in the chromosphere if the pulse is of sufficiently large amplitude and short duration. A slow shock which develops behind the Alfvenic pulse can reflect downgoing Alfven waves back up to the corona. The upgoing reflected wave can induce a significant upward ejection of the TR. Nonlinear dynamics are found to lead to very impulsive behavior at later times. It is suggested that impulsive events occurring in the TR or corona need not be interpreted in terms of reconnection-driven microflares. It is also found that B(0) in the chromosphere can be amplified when the TR and chromosphere fall.

  3. Probing the solar corona with very long baseline interferometry

    PubMed Central

    Soja, B.; Heinkelmann, R.; Schuh, H.

    2014-01-01

    Understanding and monitoring the solar corona and solar wind is important for many applications like telecommunications or geomagnetic studies. Coronal electron density models have been derived by various techniques over the last 45 years, principally by analysing the effect of the corona on spacecraft tracking. Here we show that recent observational data from very long baseline interferometry (VLBI), a radio technique crucial for astrophysics and geodesy, could be used to develop electron density models of the Sun’s corona. The VLBI results agree well with previous models from spacecraft measurements. They also show that the simple spherical electron density model is violated by regional density variations and that on average the electron density in active regions is about three times that of low-density regions. Unlike spacecraft tracking, a VLBI campaign would be possible on a regular basis and would provide highly resolved spatial–temporal samplings over a complete solar cycle. PMID:24946791

  4. HIGH SPATIAL RESOLUTION OBSERVATIONS OF LOOPS IN THE SOLAR CORONA

    SciTech Connect

    Brooks, David H.; Ugarte-Urra, Ignacio; Warren, Harry P.; Winebarger, Amy R.

    2013-08-01

    Understanding how the solar corona is structured is of fundamental importance to determine how the Sun's upper atmosphere is heated to high temperatures. Recent spectroscopic studies have suggested that an instrument with a spatial resolution of 200 km or better is necessary to resolve coronal loops. The High Resolution Coronal Imager (Hi-C) achieved this performance on a rocket flight in 2012 July. We use Hi-C data to measure the Gaussian widths of 91 loops observed in the solar corona and find a distribution that peaks at about 270 km. We also use Atmospheric Imaging Assembly data for a subset of these loops and find temperature distributions that are generally very narrow. These observations provide further evidence that loops in the solar corona are often structured at a scale of several hundred kilometers, well above the spatial scale of many proposed physical mechanisms.

  5. The Structure and Dynamics of the Corona - Heliosphere Connection

    NASA Technical Reports Server (NTRS)

    Antiochos, Spiro K.; Linker, Jon A.; Lionello, Roberto; Mikic, Zoran; Titov, Viacheslav; Zurbuchen, Thomas H.

    2010-01-01

    Determining the source at the Sun of the slow solar wind is one of the major unsolved problems in solar and heliospheric physics. First, we review the existing theories for the slow wind and argue that they have difficulty accounting for both the observed composition of the wind and its large angular extent. A new theory in which the slow wind originates from the continuous opening and closing of narrow open field corridors, the S-Web model, is described. Support for the S-Web model is derived from MHD solutions for the quasisteady corona and wind during the time of the August 1, 2008 eclipse. Additionally, we perform fully dynamic numerical simulations of the corona and heliosphere in order to test the S-Web model as well as the interchange model proposed by Fisk and co-workers. We discuss the implications of our simulations for the competing theories and for understanding the corona - heliosphere connection, in general.

  6. The Structure and Dynamics of the Corona - Heliosphere Connection

    NASA Technical Reports Server (NTRS)

    Antiochos, Spiro K.; Linker, Jon A.; Lionello, Roberto; Mikic, Zoran; Titov, Viacheslav; Zurbuchen, Thomas H.

    2011-01-01

    Determining the source at the Sun of the slow solar wind is one of the major unsolved problems in solar and heliospheric physics. First, we review the existing theories for the slow wind and argue that they have difficulty accounting for both the observed composition of the wind and its large angular extent. A new theory in which the slow wind originates from the continuous opening and closing of narrow open field corridors, the S-Web model, is described. Support for the S-Web model is derived from MHD solutions for the quasisteady corona and wind during the time of the August 1, 2008 eclipse. Additionally, we perform fully dynamic numerical simulations of the corona and heliosphere in order to test the S-Web model as well as the interchange model proposed by Fisk and co-workers. We discuss the implications of our simulations for the competing theories and for understanding the corona - heliosphere connection, in general.

  7. Spectroscopic detection of aqueous contaminants using in situ corona reactions.

    PubMed

    Johnson, M

    1997-04-01

    An apparently novel technique to aid the detection of a variety of inorganic and organic compounds in environmental and drinking water samples is described. Background absorbance due to optical scattering, cell fouling, and a variety of contaminants is suppressed by combining UV spectroscopy with chemical reactions initiated by reactive species generated in a high-voltage corona discharge. Injection of the reactive species takes place through a free water surface from the "corona wind". Initial measurements on aqueous chlorine in drinking water and BTEX (benzene, toluene, ethylbenzene, and xylene) in unfiltered river water down to parts-per-million concentration are given which show, by comparison with a conventional UV absorption measurement, good background suppression. The experimental arrangement is simpler than that in typical fluorescence detection systems, and the geometrical flexibility means that corona "dosing" can be applied also to Raman and other spectroscopies, to electrochemical detection schemes, and to planar and windowless geometries. PMID:9105172

  8. Triggering Excimer Lasers by Photoionization from Corona Discharges

    NASA Astrophysics Data System (ADS)

    Xiong, Zhongmin; Duffey, Thomas; Brown, Daniel; Kushner, Mark

    2009-10-01

    High repetition rate ArF (192 nm) excimer lasers are used for photolithography sources in microelectronics fabrication. In highly attaching gas mixtures, preionization is critical to obtaining stable, reproducible glow discharges. Photoionization from a separate corona discharge is one technique for preionization which triggers the subsequent electron avalanche between the main electrodes. Photoionization triggering of an ArF excimer laser sustained in multi-atmosphere Ne/Ar/F2/Xe gas mixtures has been investigated using a 2-dimensional plasma hydrodynamics model including radiation transport. Continuity equations for charged and neutral species, and Poisson's equation are solved coincident with the electron temperature with transport coefficients obtained from solutions of Boltzmann's equation. Photoionizing radiation is produced by a surface discharge which propagates along a corona-bar located adjacent to the discharge electrodes. The consequences of pulse power waveform, corona bar location, capacitance and gas mixture on uniformity, symmetry and gain of the avalanche discharge will be discussed.

  9. Probing the solar corona with very long baseline interferometry.

    PubMed

    Soja, B; Heinkelmann, R; Schuh, H

    2014-06-20

    Understanding and monitoring the solar corona and solar wind is important for many applications like telecommunications or geomagnetic studies. Coronal electron density models have been derived by various techniques over the last 45 years, principally by analysing the effect of the corona on spacecraft tracking. Here we show that recent observational data from very long baseline interferometry (VLBI), a radio technique crucial for astrophysics and geodesy, could be used to develop electron density models of the Sun's corona. The VLBI results agree well with previous models from spacecraft measurements. They also show that the simple spherical electron density model is violated by regional density variations and that on average the electron density in active regions is about three times that of low-density regions. Unlike spacecraft tracking, a VLBI campaign would be possible on a regular basis and would provide highly resolved spatial-temporal samplings over a complete solar cycle.

  10. Probing the solar corona with very long baseline interferometry.

    PubMed

    Soja, B; Heinkelmann, R; Schuh, H

    2014-01-01

    Understanding and monitoring the solar corona and solar wind is important for many applications like telecommunications or geomagnetic studies. Coronal electron density models have been derived by various techniques over the last 45 years, principally by analysing the effect of the corona on spacecraft tracking. Here we show that recent observational data from very long baseline interferometry (VLBI), a radio technique crucial for astrophysics and geodesy, could be used to develop electron density models of the Sun's corona. The VLBI results agree well with previous models from spacecraft measurements. They also show that the simple spherical electron density model is violated by regional density variations and that on average the electron density in active regions is about three times that of low-density regions. Unlike spacecraft tracking, a VLBI campaign would be possible on a regular basis and would provide highly resolved spatial-temporal samplings over a complete solar cycle. PMID:24946791

  11. Optical emission spectroscopy of point-plane corona and back-corona discharges in air

    NASA Astrophysics Data System (ADS)

    Czech, T.; Sobczyk, A. T.; Jaworek, A.

    2011-12-01

    Results of spectroscopic investigations and current-voltage characteristics of corona discharge and back discharge on fly-ash layer, generated in point-plane electrode geometry in air at atmospheric pressure are presented in the paper. The characteristics of both discharges are similar but differ in the current and voltage ranges of all the discharge forms distinguished during the experiments. Three forms of back discharge, for positive and negative polarity, were investigated: glow, streamer and low-current back-arc. In order to characterize ionisation and excitation processes in back discharge, the emission spectra were measured and compared with those obtained for normal corona discharge generated in the same electrode configuration but with fly ash layer removed. The emission spectra were measured in two discharge zones: near the tip of needle electrode and near the plate. Visual forms of the discharge were recorded with digital camera and referred to current-voltage characteristics and emission spectra. The measurements have shown that spectral lines emitted by back discharge depend on the form of discharge and the discharge current. From the comparison of the spectral lines of back and normal discharges an effect of fly ash layer on the discharge morphology can be determined. The recorded emission spectra formed by ionised gas and plasma near the needle electrode and fly ash layer are different. It should be noted that in back arc emission, spectral lines of fly ash layer components can be distinguished. On the other hand, in needle zone, the emission of high intensity N2 second positive system and NO γ lines can be noticed. Regardless of these gaseous lines, also atomic lines of dust layer were present in the spectrum. The differences in spectra of back discharge for positive and negative polarities of the needle electrode have been explained by considering the kind of ions generated in the crater in fly ash layer. The aim of these studies is to better

  12. A theory of heating of quiet solar corona

    SciTech Connect

    Wu, C. S.; Yoon, P. H.; Wang, C. B.

    2015-03-15

    A theory is proposed to discuss the creation of hot solar corona. We pay special attention to the transition region and the low corona, and consider that the sun is quiet. The proposed scenario suggests that the protons are heated by intrinsic Alfvénic turbulence, while the ambient electrons are heated by the hot protons via collisions. The theory contains two prime components: the generation of the Alfvénic fluctuations by the heavy minor ions in the transition region and second, the explanation of the temperature profile in the low solar atmosphere. The proposed heating process operates continuously in time and globally in space.

  13. Corona graphs as a model of small-world networks

    NASA Astrophysics Data System (ADS)

    Lv, Qian; Yi, Yuhao; Zhang, Zhongzhi

    2015-11-01

    We introduce recursive corona graphs as a model of small-world networks. We investigate analytically the critical characteristics of the model, including order and size, degree distribution, average path length, clustering coefficient, and the number of spanning trees, as well as Kirchhoff index. Furthermore, we study the spectra for the adjacency matrix and the Laplacian matrix for the model. We obtain explicit results for all the quantities of the recursive corona graphs, which are similar to those observed in real-life networks.

  14. Fabrication of Corona-Free Nanoparticles with Tunable Hydrophobicity

    PubMed Central

    2014-01-01

    A protein corona is formed at the surface of nanoparticles in the presence of biological fluids, masking the surface properties of the particle and complicating the relationship between chemical functionality and biological effects. We present here a series of zwitterionic NPs of variable hydrophobicity that do not adsorb proteins at moderate levels of serum protein and do not form hard coronas at physiological serum concentrations. These particles provide platforms to evaluate nanobiological behavior such as cell uptake and hemolysis dictated directly by chemical motifs at the nanoparticle surface. PMID:24971670

  15. Modeling high flow speeds in the inner corona

    SciTech Connect

    Esser, Ruth; Habbal, Shadia Rifai

    1996-07-20

    Following recent observations which indicate the possibility of extremely high flow speeds in the inner corona, 700-800 km s{sup -1} below 10 R{sub S}, and the possibility of very high proton temperatures, T{sub p}{<=}8.5x10{sup 6} K, we present a new approach to solar wind modeling. In this approach we show that if the high proton temperatures in the inner corona are genuine, then flow speeds of 700 to 800 km s{sup -1} can readily be achieved at 10 R{sub S} or even closer to the coronal base.

  16. Observational studies of reconnection in the solar corona

    SciTech Connect

    McKenzie, David E.

    2011-11-15

    In recent years, observational studies of the corona have shifted focus. Where they were once purely qualitative morphological explorations seeking to support the presence of reconnection, more investigations are providing empirical estimates of the physical conditions in the reconnecting corona. These studies are enabled and enhanced by orbiting telescopes with high angular and temporal resolution. In this article, some recent findings about the empirical quantities are reviewed, including recent estimates of the flux transferred in individual patchy reconnection episodes, the size distribution of post-reconnection flux tubes, and the energy released by the flux tubes as they shrink.

  17. 75 FR 8395 - Bunker Hill Groundwater Basin, Riverside-Corona Feeder Project, San Bernardino and Riverside...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-02-24

    ... Bureau of Reclamation Bunker Hill Groundwater Basin, Riverside-Corona Feeder Project, San Bernardino and.../EIR for the proposed Riverside-Corona Feeder Project. The public and agencies are invited to comment..., and construction of the Riverside-Corona Feeder Project including: (i) 20 groundwater wells;...

  18. Patchy reconnection in the solar corona

    NASA Astrophysics Data System (ADS)

    Guidoni, Silvina Esther

    2011-05-01

    Magnetic reconnection in plasmas, a process characterized by a change in connectivity of field lines that are broken and connected to other ones with different topology, owes its usefulness to its ability to unify a wide range of phenomena within a single universal principle. There are newly observed phenomena in the solar corona that cannot be reconciled with two-dimensional or steady-state standard models of magnetic reconnection. Supra-arcade downflows (SADs) and supra-arcade downflowing loops (SADLs) descending from reconnection regions toward solar post-flare arcades seem to be two different observational signatures of retracting, isolated reconnected flux tubes with irreducible three-dimensional geometries. This dissertation describes work in refining and improving a novel model of patchy reconnection, where only a small bundle of field lines is reconnected across a current sheet (magnetic discontinuity) and forms a reconnected thin flux tube. Traditional models have not been able to explain why some of the observed SADs appear to be hot and relatively devoid of plasma. The present work shows that plasma depletion naturally occurs in flux tubes that are reconnected across nonuniform current sheets and slide trough regions of decreasing magnetic field magnitude. Moreover, through a detailed theoretical analysis of generalized thin flux tube equations, we show that the addition to the model of pressure-driven parallel dynamics, as well as temperature-dependent, anisotropic viscosity and thermal conductivity is essential for self-consistently producing gas-dynamic shocks inside reconnected tubes that heat and compress plasma to observed temperatures and densities. The shock thickness can be as long as the entire tube and heat can be conducted along tube's legs, possibly driving chromospheric evaporation. We developed a computer program that solves numerically the thin flux tube equations that govern the retraction of reconnected tubes. Simulations carried out

  19. Polymer micelles with hydrophobic core and ionic amphiphilic corona. 1. Statistical distribution of charged and nonpolar units in corona.

    PubMed

    Lysenko, Evgeny A; Kulebyakina, Alevtina I; Chelushkin, Pavel S; Rumyantsev, Artem M; Kramarenko, Elena Yu; Zezin, Alexander B

    2012-12-11

    Polymer micelles with hydrophobic polystyrene (PS) core and ionic amphiphilic corona from charged N-ethyl-4-vinylpyridinium bromide (EVP) and uncharged 4-vinylpyridine (4VP) units spontaneously self-assembled from PS-block-poly(4VP-stat-EVP) macromolecules in mixed dimethylformamide/methanol/water solvent. The fraction of statistically distributed EVP units in corona-forming block is β = [EVP]/([EVP]+[4VP]) = 0.3-1. Micelles were transferred into water via dialysis technique, and pH was adjusted to 9, where 4VP is insoluble. Structural characteristics of micelles were investigated both experimentally and theoretically as a function of corona composition β. Methods of dynamic and static light scattering, electrophoretic mobility measurements, sedimentation velocity, transmission electron microscopy, and UV spectrophotometry were applied. All micelles possessed spherical morphology. The aggregation number, structure, and electrophoretic mobility of micelles changed in a jumplike manner near β ~ 0.6-0.75. Below and above this region, micelle characteristics were constant or insignificantly changed upon β. Theoretical dependencies for micelle aggregation number, corona dimensions, and fraction of small counterions outside corona versus β were derived via minimization the micelle free energy, taking into account surface, volume, electrostatic, and elastic contributions of chain units and translational entropy of mobile counterions. Theoretical estimations also point onto a sharp structural transition at a certain corona composition. The abrupt reorganization of micelle structure at β ~ 0.6-0.75 entails dramatic changes in micelle dispersion stability in the presence of NaCl or in the presence of oppositely charged polymeric (sodium polymethacrylate) or amphiphilic (sodium dodecyl sulfate) complexing agents.

  20. Nanoparticles-cell association predicted by protein corona fingerprints

    NASA Astrophysics Data System (ADS)

    Palchetti, S.; Digiacomo, L.; Pozzi, D.; Peruzzi, G.; Micarelli, E.; Mahmoudi, M.; Caracciolo, G.

    2016-06-01

    In a physiological environment (e.g., blood and interstitial fluids) nanoparticles (NPs) will bind proteins shaping a ``protein corona'' layer. The long-lived protein layer tightly bound to the NP surface is referred to as the hard corona (HC) and encodes information that controls NP bioactivity (e.g. cellular association, cellular signaling pathways, biodistribution, and toxicity). Decrypting this complex code has become a priority to predict the NP biological outcomes. Here, we use a library of 16 lipid NPs of varying size (Ø ~ 100-250 nm) and surface chemistry (unmodified and PEGylated) to investigate the relationships between NP physicochemical properties (nanoparticle size, aggregation state and surface charge), protein corona fingerprints (PCFs), and NP-cell association. We found out that none of the NPs' physicochemical properties alone was exclusively able to account for association with human cervical cancer cell line (HeLa). For the entire library of NPs, a total of 436 distinct serum proteins were detected. We developed a predictive-validation modeling that provides a means of assessing the relative significance of the identified corona proteins. Interestingly, a minor fraction of the HC, which consists of only 8 PCFs were identified as main promoters of NP association with HeLa cells. Remarkably, identified PCFs have several receptors with high level of expression on the plasma membrane of HeLa cells.In a physiological environment (e.g., blood and interstitial fluids) nanoparticles (NPs) will bind proteins shaping a ``protein corona'' layer. The long-lived protein layer tightly bound to the NP surface is referred to as the hard corona (HC) and encodes information that controls NP bioactivity (e.g. cellular association, cellular signaling pathways, biodistribution, and toxicity). Decrypting this complex code has become a priority to predict the NP biological outcomes. Here, we use a library of 16 lipid NPs of varying size (Ø ~ 100-250 nm) and surface

  1. Simultaneous Observation of High Temperature Plasma of Solar Corona By TESIS CORONAS-PHOTON and XRT Hinode.

    NASA Astrophysics Data System (ADS)

    Reva, A.; Kuzin, S.; Bogachev, S.; Shestov, S.

    2012-05-01

    The Mg XII spectroheliograph is a part of instrumentation complex TESIS (satellite CORONAS-PHOTON). This instrument builds monochromatic images of hot plasma of the solar corona (λ = 8.42 Å, T>5 MK). The Mg XII spectroheliograph observed hot plasma in the non-flaring active-region NOAA 11019 during nine days. We reconstructed DEM of this active region with the help of genetic algorithm (we used data of the Mg XII spectroheliograph, XRT and EIT). Emission measure of the hot component amounts 1 % of the emission measure of the cool component.

  2. Incremental k-core decomposition: Algorithms and evaluation

    DOE PAGESBeta

    Sariyuce, Ahmet Erdem; Gedik, Bugra; Jacques-SIlva, Gabriela; Wu, Kun -Lung; Catalyurek, Umit V.

    2016-02-01

    A k-core of a graph is a maximal connected subgraph in which every vertex is connected to at least k vertices in the subgraph. k-core decomposition is often used in large-scale network analysis, such as community detection, protein function prediction, visualization, and solving NP-hard problems on real networks efficiently, like maximal clique finding. In many real-world applications, networks change over time. As a result, it is essential to develop efficient incremental algorithms for dynamic graph data. In this paper, we propose a suite of incremental k-core decomposition algorithms for dynamic graph data. These algorithms locate a small subgraph that ismore » guaranteed to contain the list of vertices whose maximum k-core values have changed and efficiently process this subgraph to update the k-core decomposition. We present incremental algorithms for both insertion and deletion operations, and propose auxiliary vertex state maintenance techniques that can further accelerate these operations. Our results show a significant reduction in runtime compared to non-incremental alternatives. We illustrate the efficiency of our algorithms on different types of real and synthetic graphs, at varying scales. Furthermore, for a graph of 16 million vertices, we observe relative throughputs reaching a million times, relative to the non-incremental algorithms.« less

  3. Regulation of Macrophage Recognition through the Interplay of Nanoparticle Surface Functionality and Protein Corona.

    PubMed

    Saha, Krishnendu; Rahimi, Mehran; Yazdani, Mahdieh; Kim, Sung Tae; Moyano, Daniel F; Hou, Singyuk; Das, Ridhha; Mout, Rubul; Rezaee, Farhad; Mahmoudi, Morteza; Rotello, Vincent M

    2016-04-26

    Using a family of cationic gold nanoparticles (NPs) with similar size and charge, we demonstrate that proper surface engineering can control the nature and identity of protein corona in physiological serum conditions. The protein coronas were highly dependent on the hydrophobicity and arrangement of chemical motifs on NP surface. The NPs were uptaken in macrophages in a corona-dependent manner, predominantly through recognition of specific complement proteins in the NP corona. Taken together, this study shows that surface functionality can be used to tune the protein corona formed on NP surface, dictating the interaction of NPs with macrophages.

  4. Ultralong optical-pulse corona preionized XeCl laser

    SciTech Connect

    Taylor, R.S.; Leopold, K.E.

    1989-01-01

    A simple corona preionization scheme together with magnetic spiker and pulse forming line technology has resulted in the production of 100-mJ, 1-..mu..s duration as well as 500-mJ, 0.5-..mu..s duration XeCl laser pulses.

  5. Semi-analytical modelling of positive corona discharge in air

    NASA Astrophysics Data System (ADS)

    Pontiga, Francisco; Yanallah, Khelifa; Chen, Junhong

    2013-09-01

    Semianalytical approximate solutions of the spatial distribution of electric field and electron and ion densities have been obtained by solving Poisson's equations and the continuity equations for the charged species along the Laplacian field lines. The need to iterate for the correct value of space charge on the corona electrode has been eliminated by using the corona current distribution over the grounded plane derived by Deutsch, which predicts a cos m θ law similar to Warburg's law. Based on the results of the approximated model, a parametric study of the influence of gas pressure, the corona wire radius, and the inter-electrode wire-plate separation has been carried out. Also, the approximate solutions of the electron number density has been combined with a simplified plasma chemistry model in order to compute the ozone density generated by the corona discharge in the presence of a gas flow. This work was supported by the Consejeria de Innovacion, Ciencia y Empresa (Junta de Andalucia) and by the Ministerio de Ciencia e Innovacion, Spain, within the European Regional Development Fund contracts FQM-4983 and FIS2011-25161.

  6. Observational Signatures of Magnetic Reconnection in the Extended Corona

    NASA Technical Reports Server (NTRS)

    Savage, Sabrina; West, Matthew J.; Seaton, Daniel B.; Kobelski, Adam

    2016-01-01

    Observational signatures of reconnection have been studied extensively in the lower corona for decades, successfully providing insight into energy release mechanisms in the region above post-flare arcade loops and below 1.5 solar radii. During large eruptive events, however, energy release continues to occur well beyond the presence of reconnection signatures at these low heights. Supra-Arcade Downflows (SADs) and Supra-Arcade Downflowing Loops (SADLs) are particularly useful measures of continual reconnection in the corona as they may indicate the presence and path of retracting post-reconnection loops. SADs and SADLs have been faintly observed up to 18 hours beyond the passage of coronas mass ejections through the SOHO/LASCO field of view, but a recent event from 2014 October 14 associated with giant arches provides very clear observations of these downflows for days after the initial eruption. We report on this unique event and compare these findings with observational signatures of magnetic reconnection in the extended corona for more typical eruptions.

  7. Observational Signatures of Magnetic Reconnection in the Extended Corona

    NASA Astrophysics Data System (ADS)

    Savage, Sabrina; West, Matthew; Seaton, Daniel B.; Kobelski, Adam

    2016-05-01

    Observational signatures of reconnection have been studied extensively in the lower corona for decades, successfully providing insight into energy release mechanisms in the region above post-flare arcade loops and below 1.5 solar radii. During large eruptive events, however, energy release continues to occur well beyond the presence of reconnection signatures at these low heights. Supra-arcade downflows (SADs) and downflowing loops (SADLs) are particularly useful measures of continual reconnection in the corona as they may indicate the presence and path of retracting post-reconnection loops. SADs and SADLs have been faintly observed up to 18 hours beyond the passage of corona mass ejections through the SOHO/LASCO field of view, but a recent event from 2014 October 14 associated with giant arches provides very clear observations of these downflows for days after the initial eruption. We report on this unique event and compare these findings with observational signatures of magnetic reconnection in the extended corona for more typical eruptions.

  8. Plasma Compression in Magnetic Reconnection Regions in the Solar Corona

    NASA Astrophysics Data System (ADS)

    Provornikova, E.; Laming, J. M.; Lukin, V. S.

    2016-07-01

    It has been proposed that particles bouncing between magnetized flows converging in a reconnection region can be accelerated by the first-order Fermi mechanism. Analytical considerations of this mechanism have shown that the spectral index of accelerated particles is related to the total plasma compression within the reconnection region, similarly to the case of the diffusive shock acceleration mechanism. As a first step to investigate the efficiency of Fermi acceleration in reconnection regions in producing hard energy spectra of particles in the solar corona, we explore the degree of plasma compression that can be achieved at reconnection sites. In particular, we aim to determine the conditions for the strong compressions to form. Using a two-dimensional resistive MHD numerical model, we consider a set of magnetic field configurations where magnetic reconnection can occur, including a Harris current sheet, a force-free current sheet, and two merging flux ropes. Plasma parameters are taken to be characteristic of the solar corona. Numerical simulations show that strong plasma compressions (≥4) in the reconnection regions can form when the plasma heating due to reconnection is efficiently removed by fast thermal conduction or the radiative cooling process. The radiative cooling process that is negligible in the typical 1 MK corona can play an important role in the low corona/transition region. It is found that plasma compression is expected to be strongest in low-beta plasma β ˜ 0.01–0.07 at reconnection magnetic nulls.

  9. 37. VIEW OF SIX GAP ROTARY RECTIFIER FOR MAINTAINING CORONA ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    37. VIEW OF SIX GAP ROTARY RECTIFIER FOR MAINTAINING CORONA DISCHARGE IN THE COTTRELL ELECTROSTATIC GENERATORS. THE SYSTEM WAS CAPABLE OF PROVIDING 88,000 VOLTS TO THE ELECTRODES WITHIN THE PRECIPITATOR CHAMBER THE UNIT WAS LOCATED TO THE REAR OF BOILER 904 IN AN ENCLOSED ROOM. - New York, New Haven & Hartford Railroad, Cos Cob Power Plant, Sound Shore Drive, Greenwich, Fairfield County, CT

  10. Simulating halos and coronas in their atmospheric environment.

    PubMed

    David Gedzelman, Stanley

    2008-12-01

    Models are developed that simulate the light and color of the sky and of circular halos and coronas as a function of atmospheric pressure, cloud height, width, and optical depth, solar zenith angle, aerosol concentration and size, and ozone content. Halos, coronas, and skylight are treated as singly scattered sunbeams that are depleted in their passage through the atmosphere and cloud. Multiple scattering is included only for background cloud light. Halos produced by hexagonal crystal prisms and coronas produced by monodisperse droplets are visible for cloud optical depths in the range 0.0003 coronas can be bright only at smaller cloud optical depths and tend to be faint at their bottoms when produced in high cloud layers but can be bright at the horizon when produced by narrow cloud cells near ground level.

  11. DBD-Corona Discharge for Degradation of Toxic Gases

    NASA Astrophysics Data System (ADS)

    Pacheco-Pacheco, M.; Pacheco-Sotelo, J.; Moreno-Saavedra, H.; A. Diaz-Gomez, J.; Mercado-Cabrera, A.; Yousfi, M.

    2007-12-01

    The non-thermal plasma technology is a promising technique to treat SO2 and NOx. Chemical radicals produced with this technology can remove several pollutants at atmospheric pressure in a very short period of time simultaneously. Both theoretical and experimental study on SO2 and NOx removal, by a dielectric barrier discharge (DBD) with corona effect, is presented.

  12. Energy distribution of nanoflares in the quiet solar corona

    NASA Astrophysics Data System (ADS)

    Ulyanov, Artyom

    2012-07-01

    We present a detailed statistical analysis of flare-like events in low layer of solar corona detected with TESIS instrument onboard CORONAS-PHOTON satellite in 171 {Å} during high-cadence (5 sec) time-series. The estimated thermal energies of these small events amount to 10^{23} - 10^{26} erg. According to modern classification flare-like events with such energies are usually referred to as nanoflares. The big number of registered events (above 2000) allowed us to obtain precise distributions of geometric and physical parameters of nanoflares, the most intriguing being energy distribution. Following Aschwanden et al. (2000) and other authors we approximated the calculated energy distribution with a single power law slope: N(E)dE ˜ N^{-α}dE. The power law index was derived to be α = 2.4 ± 0.2, which is very close to the value reported by Krucker & Benz (1998): α ≈ 2.3 - 2.4. The total energy input from registered events constitute about 10^4 erg \\cdot cm^{-2} \\cdot s^{-1}, which is well beyond net losses in quiet corona (3 \\cdot 10^5 erg \\cdot cm^{-2} \\cdot s^{-1}). However, the value of α > 2 indicates that nanoflares with lower energies dominate over nanoflares with bigger energies and could contribute considerably to quiet corona heating.

  13. The airflow effect on a negative corona discharge

    NASA Astrophysics Data System (ADS)

    Amirov, R. Kh.; Barengol'ts, S. A.; Korostelev, E. V.; Pestovskii, N. V.; Petrov, A. A.; Savinov, S. Yu.; Samoilov, I. S.

    2016-09-01

    The effect of the airflow on the negative corona discharge is studied. It is shown by use of telemicroscopy that the localization of the discharge torch on the cathode surface can be significantly affected by the aerodynamic action on the discharge gap region.

  14. Criterion and incremental validity of the emotion regulation questionnaire

    PubMed Central

    Ioannidis, Christos A.; Siegling, A. B.

    2015-01-01

    Although research on emotion regulation (ER) is developing, little attention has been paid to the predictive power of ER strategies beyond established constructs. The present study examined the incremental validity of the Emotion Regulation Questionnaire (ERQ; Gross and John, 2003), which measures cognitive reappraisal and expressive suppression, over and above the Big Five personality factors. It also extended the evidence for the measure's criterion validity to yet unexamined criteria. A university student sample (N = 203) completed the ERQ, a measure of the Big Five, and relevant cognitive and emotion-laden criteria. Cognitive reappraisal predicted positive affect beyond personality, as well as experiential flexibility and constructive self-assertion beyond personality and affect. Expressive suppression explained incremental variance in negative affect beyond personality and in experiential flexibility beyond personality and general affect. No incremental effects were found for worry, social anxiety, rumination, reflection, and preventing negative emotions. Implications for the construct validity and utility of the ERQ are discussed. PMID:25814967

  15. A heuristic approach to incremental and reactive scheduling

    NASA Technical Reports Server (NTRS)

    Odubiyi, Jide B.; Zoch, David R.

    1989-01-01

    An heuristic approach to incremental and reactive scheduling is described. Incremental scheduling is the process of modifying an existing schedule if the initial schedule does not meet its stated initial goals. Reactive scheduling occurs in near real-time in response to changes in available resources or the occurrence of targets of opportunity. Only minor changes are made during both incremental and reactive scheduling because a goal of re-scheduling procedures is to minimally impact the schedule. The described heuristic search techniques, which are employed by the Request Oriented Scheduling Engine (ROSE), a prototype generic scheduler, efficiently approximate the cost of reaching a goal from a given state and effective mechanisms for controlling search.

  16. Incremental comprehension of spoken quantifier sentences: Evidence from brain potentials.

    PubMed

    Freunberger, Dominik; Nieuwland, Mante S

    2016-09-01

    Do people incrementally incorporate the meaning of quantifier expressions to understand an unfolding sentence? Most previous studies concluded that quantifiers do not immediately influence how a sentence is understood based on the observation that online N400-effects differed from offline plausibility judgments. Those studies, however, used serial visual presentation (SVP), which involves unnatural reading. In the current ERP-experiment, we presented spoken positive and negative quantifier sentences ("Practically all/practically no postmen prefer delivering mail, when the weather is good/bad during the day"). Different from results obtained in a previously reported SVP-study (Nieuwland, 2016) sentence truth-value N400 effects occurred in positive and negative quantifier sentences alike, reflecting fully incremental quantifier comprehension. This suggests that the prosodic information available during spoken language comprehension supports the generation of online predictions for upcoming words and that, at least for quantifier sentences, comprehension of spoken language may proceed more incrementally than comprehension during SVP reading. PMID:27346365

  17. First incremental buy for Increment 2 of the Space Transportation System (STS)

    NASA Technical Reports Server (NTRS)

    1989-01-01

    Thiokol manufactured and delivered 9 flight motors to KSC on schedule. All test flights were successful. All spent SRMs were recovered. Design, development, manufacture, and delivery of required transportation, handling, and checkout equipment to MSFC and to KSC were completed on schedule. All items of data required by DPD 400 were prepared and delivered as directed. In the system requirements and analysis area, the point of departure from Buy 1 to the operational phase was developed in significant detail with a complete set of transition documentation available. The documentation prepared during the Buy 1 program was maintained and updated where required. The following flight support activities should be continued through other production programs: as-built materials usage tracking on all flight hardware; mass properties reporting for all flight hardware until sample size is large enough to verify that the weight limit requirements were met; ballistic predictions and postflight performance assessments for all production flights; and recovered SRM hardware inspection and anomaly identification. In the safety, reliability, and quality assurance area, activities accomplished were assurance oriented in nature and specifically formulated to prevent problems and hardware failures. The flight program to date has adequately demonstrated the success of this assurance approach. The attention focused on details of design, analysis, manufacture, and inspection to assure the production of high-quality hardware has resulted in the absence of flight failures. The few anomalies which did occur were evaluated, design or manufacturing changes incorporated, and corrective actions taken to preclude recurrence.

  18. Outflowing X-ray corona in Active Galactic Nuclei

    NASA Astrophysics Data System (ADS)

    Wang, Junxian; Liu, Teng; Yang, Huan; Zhu, Feifan; Zhou, Youyuan

    2015-08-01

    Hard X-ray emission in radio-quiet AGNs is believed to be produced via inverse Compton scattering by hot and compact corona near the super massive black hole. However the origin and physical properties of the coronae, including geometry, kinematics and dynamics, yet remain poorly known. Taking [OIV] 25.89um emission line as an isotropic indicator of AGN's intrinsic luminosity, we compare the intrinsic corona X-ray emission between Seyfert 1 and Compton-thin Seyfert 2 galaxies, which are viewed at different inclinations according to the unification scheme. We find that Seyfert 1 galaxies are brighter in "absorption-corrected" 2-10 keV emission by a factor of ~2.8, comparing with Compton-thin Seyfert 2 galaxies. The Seyfert 1 and Compton-thin Seyfert 2 galaxies follow a statistically identical correlation between the absorption-corrected 2-10 keV luminosity and the SWIFT BAT 14-195 keV luminosity, indicating that our absorption correction to the 2-10 keV flux is sufficient. The difference between the two populations thus can not be attributed to X-ray absorption, and instead implies an intrinsic anisotropy in the corona X-ray emission. This striking anisotropy of X-ray emission can be explained by a bipolar outflowing corona with a bulk velocity of ~0.3-0.5c. This would provide a natural link between the so-called coronae and weak jets in these systems. We also show that how this study would affect our understanding to the nature of mid-infrared emission in AGNs and the properties of dusty torus. Furthermore, such anisotropy implies that, contrary to previous understanding based on the assumption of isotropic corona emission, hard X-ray AGN surveys are biased against type 2 AGNs even after absorption-correction, and careful correction for this effect is required to measure the obscured fraction from X-ray surveys. Other interesting consequences of this discovery will also be discussed.

  19. Factors for radical creativity, incremental creativity, and routine, noncreative performance.

    PubMed

    Madjar, Nora; Greenberg, Ellen; Chen, Zheng

    2011-07-01

    This study extends theory and research by differentiating between routine, noncreative performance and 2 distinct types of creativity: radical and incremental. We also use a sensemaking perspective to examine the interplay of social and personal factors that may influence a person's engagement in a certain level of creative action versus routine, noncreative work. Results demonstrate that willingness to take risks, resources for creativity, and career commitment are associated primarily with radical creativity; that the presence of creative coworkers and organizational identification are associated with incremental creativity; and that conformity and organizational identification are linked with routine performance. Theoretical and managerial implications are discussed.

  20. Lubrication study for Single Point Incremental Forming of Copper

    NASA Astrophysics Data System (ADS)

    Jawale, Kishore; Ferreira Duarte, José; Reis, Ana; Silva, M. B.

    2016-08-01

    In conventional machining and sheet metal forming processes, in general, lubrication assists to increase the quality of the final product. Similarly it is observed that there is a positive effect of the use of lubrication in Single point incremental forming, namely in the surface roughness. This study is focused on the investigation of the most appropriate lubricant for incremental forming of copper sheet. The study involves the selection of the best lubricant from a range of several lubricants that provides the best surface finishing. The influence of the lubrication on other parameters such as the maximum forming angle, the fracture strains and the deformed profile are also studied for Copper.

  1. Release timescales of solar energetic particles in the low corona

    NASA Astrophysics Data System (ADS)

    Agueda, N.; Klein, K.-L.; Vilmer, N.; Rodríguez-Gasén, R.; Malandraki, O. E.; Papaioannou, A.; Subirà, M.; Sanahuja, B.; Valtonen, E.; Dröge, W.; Nindos, A.; Heber, B.; Braune, S.; Usoskin, I. G.; Heynderickx, D.; Talew, E.; Vainio, R.

    2014-10-01

    Aims: We present a systematic study of the timing and duration of the release processes of near-relativistic (NR; >50 keV) electrons in the low corona. Methods: We analyze seven well-observed events using in situ measurements by both the ACE and Wind spacecraft and context electromagnetic observations in soft X-rays, radio, hard X-rays and white light. We make use of velocity dispersion analysis to estimate the release time of the first arriving electrons and compare with the results obtained by using a simulation-based approach, taking interplanetary transport effects into account to unfold the NR electron release time history from in situ measurements. Results: The NR electrons observed in interplanetary space appear to be released during either short (<30 min) or long (>2 h) periods. The observation of NR electron events showing beamed pitch-angle distributions (PADs) during several hours is the clearest observational signature of sustained release in the corona. On the other hand, the in situ observation of PADs isotropizing in less than a couple of hours is a clear signature of a prompt release of electrons in the low corona. Short release episodes appear to originate in solar flares, in coincidence with the timing of the observed type III radio bursts. Magnetic connectivity plays an important role. Only type III radio bursts reaching the local plasma line measured at 1 AU are found to be related with an associated release episode in the low corona. Other type III bursts may also have a release of NR electrons associated with them, but these electrons do not reach L1. Long release episodes appear associated with signatures of long acceleration processes in the low corona (long decay of the soft X-ray emission, type IV radio bursts, and time-extended microwave emission). Type II radio bursts are reported for most of the events and do not provide a clear discrimination between short and long release timescales.

  2. Experimental Study of Corona Properties with a Heated Discharge Electrode and Crossed Magnetic Fields Individually

    NASA Astrophysics Data System (ADS)

    Abu-Elabass, Karim

    2016-09-01

    This work involves ac and dc corona in air with heated discharge electrode, and breakdown streamers in corona in a crossed magnetic field. At first, the triggering of the breakdown streamers in positive and ac corona are governed by the temperature of the discharge electrode. In the negative corona, however, the breakdown streamers found to be practically independent of the temperature of the discharge electrode. Then, the transverse magnetic field, applied perpendicularly to the electric field, result in an improvement in pre-breakdown characteristic of the wire-tube gap. The application of the transverse field has the effect of increasing the corona onset voltage and the breakdown voltage. Also the transverse applied field has the effect of decreasing the corona current. It has been observed that triggering of the breakdown streamers in negative corona is affected appreciably by the transverse magnetic field.

  3. Observations of selected coronae from Venusian quadrangles V31 and V19

    NASA Astrophysics Data System (ADS)

    Copp, Duncan L.; Guest, John E.; Stofan, Ellen R.

    1997-03-01

    Observations from FMAP images and topographic data reveal coronae within V31 and V19 to have a more complex, protracted history than previously recorded. Five coronae are studied here in detail: the Idem-Kuva and Nissaba coronae situated on the Western Eistla Rise and the Heng-o, Beten, and Silvia coronae contained with the Guinevere Lineated and Mottled Plains and Guinevere Regional Plains units. It is inferred that the amount of relief at any individual corona is more strongly controlled by the amount of uplift and/or volcanic construction which has taken place, and that not all coronae may go through a dome or plateau-shaped phase. It is also shown that coronae both pre- and post-date formation of the adjacent plains and can have a long, complex geologic history.

  4. Exploring the prominence-corona connection and its expansion into the outer corona using total solar eclipse observations

    SciTech Connect

    Habbal, Shadia Rifai; Morgan, Huw; Druckmüller, Miloslav

    2014-10-01

    Prominences constitute the most complex magnetic structures in the solar corona. The ubiquitous presence of their seemingly confined dense and cool plasma in an otherwise million-degree environment remains a puzzle. Using a decade of white light total solar eclipse observations, we show how these images reveal an intricate relationship between prominences and coronal structures both in their immediate vicinity, known as coronal cavities, and in the extended corona out to several solar radii. Observations of suspended prominences and twisted helical structures spanning several solar radii are central to these findings. The different manifestations of the prominence-corona interface that emerge from this study underscore the fundamental role played by prominences in defining and controlling the complex expansion and dynamic behavior of the solar magnetic field in the neighborhood of magnetic polarity reversal regions. This study suggests that the unraveling of prominences and the outward expansion of the helical twisted field lines linked to them could be the solar origin of twisted magnetic flux ropes detected in interplanetary space, and of the mechanism by which the Sun sheds its magnetic helicity. This work also underscores the likely role of the prominence-corona interface as a source of the slow solar wind.

  5. Investigation of the nonlinear seismic behavior of knee braced frames using the incremental dynamic analysis method

    NASA Astrophysics Data System (ADS)

    Sheidaii, Mohammad Reza; TahamouliRoudsari, Mehrzad; Gordini, Mehrdad

    2016-06-01

    In knee braced frames, the braces are attached to the knee element rather than the intersection of beams and columns. This bracing system is widely used and preferred over the other commonly used systems for reasons such as having lateral stiffness while having adequate ductility, damage concentration on the second degree convenience of repairing and replacing of these elements after Earthquake. The lateral stiffness of this system is supplied by the bracing member and the ductility of the frame attached to the knee length is supplied through the bending or shear yield of the knee member. In this paper, the nonlinear seismic behavior of knee braced frame systems has been investigated using incremental dynamic analysis (IDA) and the effects of the number of stories in a building, length and the moment of inertia of the knee member on the seismic behavior, elastic stiffness, ductility and the probability of failure of these systems has been determined. In the incremental dynamic analysis, after plotting the IDA diagrams of the accelerograms, the collapse diagrams in the limit states are determined. These diagrams yield that for a constant knee length with reduced moment of inertia, the probability of collapse in limit states heightens and also for a constant knee moment of inertia with increasing length, the probability of collapse in limit states increases.

  6. Contamination of Composite Resin by Glove Powder and Saliva Contaminants: Impact on Mechanical Properties and Incremental Layer Debonding.

    PubMed

    Martins, N M; Schmitt, G U; Oliveira, H L; Madruga, M M; Moraes, R R; Cenci, M S

    2015-01-01

    This study investigated the influence of digital manipulation of a composite resin (Z250; 3M ESPE, St Paul, MN, USA) with gloves contaminated with powder and/or human stimulated saliva on the mechanical properties and incremental layer debonding of the restorative. The six groups tested were powdered gloves with or without saliva, powder-free gloves with or without saliva, powdered gloves with saliva cleaned with 70% ethanol, and no digital manipulation or contamination (control). Diametral tensile strength, flexural strength, flexural modulus, and incremental layer shear bond strength were evaluated. Each composite increment was digitally manipulated for 10 seconds. Data from each test were separately analyzed using analysis of variance and the Student-Newman-Keuls test (α=0.05). No significant differences for diametral tensile strength were observed. Manipulation of the composite using powder-free gloves with saliva or using gloves cleaned with ethanol generated higher flexural strength and modulus compared to the other groups. The control group and the group manipulated using powdered gloves with saliva generally showed lower mechanical performances. Lower incremental layer bond strength was observed for the group manipulated with powdered gloves without saliva. The control group and the groups manipulated with powdered gloves with saliva or cleaned with ethanol showed higher shear bond strengths. Most of the failures were cohesive. In conclusion, digital manipulation might be important for the composite resin to achieve better mechanical performance and incremental layer bond strength, provided that the gloves are not contaminated. Cleaning the gloves with ethanol might avoid the negative effects of digital manipulation using contaminated gloves.

  7. Retroactive Operations: On "Increments" in Mandarin Chinese Conversations

    ERIC Educational Resources Information Center

    Lim, Ni Eng

    2014-01-01

    Conversation Analysis (CA) has established repair (Schegloff, Jefferson & Sacks 1977; Schegloff 1979; Kitzinger 2013) as a conversational mechanism for managing contingencies of talk-in-interaction. In this dissertation, I look at a particular sort of "repair" termed TCU-continuations (or otherwise known increments in other…

  8. Assessing the Incremental Algorithm: A Response to Krahmer et al.

    ERIC Educational Resources Information Center

    van Deemter, Kees; Gatt, Albert; van der Sluis, Ielka; Power, Richard

    2012-01-01

    This response discusses the experiment reported in Krahmer et al.'s Letter to the Editor of "Cognitive Science". We observe that their results do not tell us whether the Incremental Algorithm is better or worse than its competitors, and we speculate about implications for reference in complex domains, and for learning from "normal" (i.e.,…

  9. Against the Odds: Academic Underdogs Benefit from Incremental Theories

    ERIC Educational Resources Information Center

    Davis, Jody L.; Burnette, Jeni L.; Allison, Scott T.; Stone, Heather

    2011-01-01

    An implicit theory of ability approach to motivation argues that students who believe traits to be malleable (incremental theorists), relative to those who believe traits to be fixed (entity theorists), cope more effectively when academic challenges arise. In the current work, we integrated the implicit theory literature with research on top dog…

  10. 17 CFR 242.612 - Minimum pricing increment.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 17 Commodity and Securities Exchanges 3 2010-04-01 2010-04-01 false Minimum pricing increment. 242.612 Section 242.612 Commodity and Securities Exchanges SECURITIES AND EXCHANGE COMMISSION (CONTINUED) REGULATIONS M, SHO, ATS, AC, AND NMS AND CUSTOMER MARGIN REQUIREMENTS FOR SECURITY FUTURES Regulation...

  11. 76 FR 53763 - Immigration Benefits Business Transformation, Increment I

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-29

    ... Benefits Business Transformation, Increment I AGENCY: U.S. Citizenship and Immigration Services, DHS... its regulations to enable U.S. Citizenship and Immigration Services (USCIS) to migrate from a paper file-based, non-integrated systems environment to an electronic customer-focused, centralized...

  12. Incremental Validity in the Clinical Assessment of Early Childhood Development

    ERIC Educational Resources Information Center

    Liu, Xin; Zhou, Xiaobin; Lackaff, Julie

    2013-01-01

    The authors demonstrate the increment of clinical validity in early childhood assessment of physical impairment (PI), developmental delay (DD), and autism (AUT) using multiple standardized developmental screening measures such as performance measures and parent and teacher rating scales. Hierarchical regression and sensitivity/specificity analyses…

  13. Generation of Referring Expressions: Assessing the Incremental Algorithm

    ERIC Educational Resources Information Center

    van Deemter, Kees; Gatt, Albert; van der Sluis, Ielka; Power, Richard

    2012-01-01

    A substantial amount of recent work in natural language generation has focused on the generation of "one-shot" referring expressions whose only aim is to identify a target referent. Dale and Reiter's Incremental Algorithm (IA) is often thought to be the best algorithm for maximizing the similarity to referring expressions produced by people. We…

  14. Tax Increment Financing and Education Expenditures: The Case of Iowa

    ERIC Educational Resources Information Center

    Nguyen-Hoang, Phuong

    2014-01-01

    This is the first study to directly examine the relationship between tax increment financing (TIF) and education expenditures, using the state of Iowa as a case study. I find that greater use of TIF is associated with reduced education expenditures. I also find little evidence to support the commonly held proposition that school spending increases…

  15. Predicting Robust Vocabulary Growth from Measures of Incremental Learning

    ERIC Educational Resources Information Center

    Frishkoff, Gwen A.; Perfetti, Charles A.; Collins-Thompson, Kevyn

    2011-01-01

    We report a study of incremental learning of new word meanings over multiple episodes. A new method called MESA (Markov Estimation of Semantic Association) tracked this learning through the automated assessment of learner-generated definitions. The multiple word learning episodes varied in the strength of contextual constraint provided by…

  16. 76 FR 73475 - Immigration Benefits Business Transformation, Increment I; Correction

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-11-29

    .... Correction of Publication Accordingly, the publication on August 29, 2011 (76 FR 53764) of the final rule that was the subject of FR Doc. 2011-20990 is corrected as follows: PART 103--IMMIGRATION BENEFITS... Benefits Business Transformation, Increment I, 76 FR 53764 (Aug. 29, 2011). The final rule removed...

  17. Incremental logistic regression for customizing automatic diagnostic models.

    PubMed

    Tortajada, Salvador; Robles, Montserrat; García-Gómez, Juan Miguel

    2015-01-01

    In the last decades, and following the new trends in medicine, statistical learning techniques have been used for developing automatic diagnostic models for aiding the clinical experts throughout the use of Clinical Decision Support Systems. The development of these models requires a large, representative amount of data, which is commonly obtained from one hospital or a group of hospitals after an expensive and time-consuming gathering, preprocess, and validation of cases. After the model development, it has to overcome an external validation that is often carried out in a different hospital or health center. The experience is that the models show underperformed expectations. Furthermore, patient data needs ethical approval and patient consent to send and store data. For these reasons, we introduce an incremental learning algorithm base on the Bayesian inference approach that may allow us to build an initial model with a smaller number of cases and update it incrementally when new data are collected or even perform a new calibration of a model from a different center by using a reduced number of cases. The performance of our algorithm is demonstrated by employing different benchmark datasets and a real brain tumor dataset; and we compare its performance to a previous incremental algorithm and a non-incremental Bayesian model, showing that the algorithm is independent of the data model, iterative, and has a good convergence. PMID:25417079

  18. The Incremental Validity of Positive Emotions in Predicting School Functioning

    ERIC Educational Resources Information Center

    Lewis, Ashley D.; Huebner, E. Scott; Reschly, Amy L.; Valois, Robert F.

    2009-01-01

    Proponents of positive psychology have argued for more comprehensive assessments incorporating positive measures (e.g., student strengths) as well as negative measures (e.g., psychological symptoms). However, few variable-centered studies have addressed the incremental validity of positive assessment data. The authors investigated the incremental…

  19. Factors for Radical Creativity, Incremental Creativity, and Routine, Noncreative Performance

    ERIC Educational Resources Information Center

    Madjar, Nora; Greenberg, Ellen; Chen, Zheng

    2011-01-01

    This study extends theory and research by differentiating between routine, noncreative performance and 2 distinct types of creativity: radical and incremental. We also use a sensemaking perspective to examine the interplay of social and personal factors that may influence a person's engagement in a certain level of creative action versus routine,…

  20. Diagnosing the Prominence-Cavity Connection in the Solar Corona

    NASA Astrophysics Data System (ADS)

    Schmit, D. J.

    The energetic equilibrium of the corona is described by a balance of heating, thermal conduction, and radiative cooling. Prominences can be described by the thermal instability of coronal energy balance which leads to the formation of cool condensations. Observationally, the prominence is surrounded by a density depleted elliptical structure known as a cavity. In this dissertation, we use extreme ultraviolet remote sensing observations of the prominence-cavity system to diagnose the static and dynamic properties of these structures. The observations are compared with numerical models for the time-dependent coronal condensation process and the time-independent corona-prominence magnetic field. To diagnose the density of the cavity, we construct a three-dimensional structural model of the corona. This structural model allows us to synthesize extreme ultraviolet emission in the corona in a way that incorporates the projection effects which arise from the optically thin plasma. This forward model technique is used to constrain a radial density profile simultaneously in the cavity and the streamer. We use a χ2 minimization to find the density model which best matches a density sensitive line ratio (observed with Hinode/Extreme ultraviolet Imaging Spectrometer) and the white light scattered intensity (observed with Mauna Loa Solar Observatory MK4 coronagraph). We use extreme ultraviolet spectra and spectral images to diagnose the dynamics of the prominence and the surrounding corona. Based on the doppler shift of extreme ultraviolet coronal emission lines, we find that there are large regions of flowing plasma which appear to occur within cavities. These line of sight flows have speeds of 10 km/s-1 and projected spatial scales of 100 Mm. Using the Solar Dynamics Observatory Atmospheric Imaging Assembly (SDO/AIA) dataset, we observe dynamic emission from the prominence-cavity system. The SDO/AIA dataset observes multiple spectral bandpasses with different temperature

  1. The biomolecular corona of nanoparticles in circulating biological media

    NASA Astrophysics Data System (ADS)

    Pozzi, D.; Caracciolo, G.; Digiacomo, L.; Colapicchioni, V.; Palchetti, S.; Capriotti, A. L.; Cavaliere, C.; Zenezini Chiozzi, R.; Puglisi, A.; Laganà, A.

    2015-08-01

    When nanoparticles come into contact with biological media, they are covered by a biomolecular `corona', which confers a new identity to the particles. In all the studies reported so far nanoparticles are incubated with isolated plasma or serum that are used as a model for protein adsorption. Anyway, bodily fluids are dynamic in nature so the question arises on whether the incubation protocol, i.e. dynamic vs. static incubation, could affect the composition and structure of the biomolecular corona. Here we let multicomponent liposomes interact with fetal bovine serum (FBS) both statically and dynamically, i.e. in contact with circulating FBS (~40 cm s-1). The structure and composition of the liposome-protein corona, as determined by dynamic light scattering, electrophoretic light scattering and liquid chromatography tandem mass spectrometry, were found to be dependent on the incubation protocol. Specifically, following dynamic exposure to FBS, multicomponent liposomes were less enriched in complement proteins and appreciably more enriched in apolipoproteins and acute phase proteins (e.g. alpha-1-antitrypsin and inter-alpha-trypsin inhibitor heavy chain H3) that are involved in relevant interactions between nanoparticles and living systems. Supported by our results, we speculate that efficient predictive modeling of nanoparticle behavior in vivo will require accurate knowledge of nanoparticle-specific protein fingerprints in circulating biological media.When nanoparticles come into contact with biological media, they are covered by a biomolecular `corona', which confers a new identity to the particles. In all the studies reported so far nanoparticles are incubated with isolated plasma or serum that are used as a model for protein adsorption. Anyway, bodily fluids are dynamic in nature so the question arises on whether the incubation protocol, i.e. dynamic vs. static incubation, could affect the composition and structure of the biomolecular corona. Here we let

  2. Understanding the incremental value of novel diagnostic tests for tuberculosis.

    PubMed

    Arinaminpathy, Nimalan; Dowdy, David

    2015-12-01

    Tuberculosis is a major source of global mortality caused by infection, partly because of a tremendous ongoing burden of undiagnosed disease. Improved diagnostic technology may play an increasingly crucial part in global efforts to end tuberculosis, but the ability of diagnostic tests to curb tuberculosis transmission is dependent on multiple factors, including the time taken by a patient to seek health care, the patient's symptoms, and the patterns of transmission before diagnosis. Novel diagnostic assays for tuberculosis have conventionally been evaluated on the basis of characteristics such as sensitivity and specificity, using assumptions that probably overestimate the impact of diagnostic tests on transmission. We argue for a shift in focus to the evaluation of such tests' incremental value, defining outcomes that reflect each test's purpose (for example, transmissions averted) and comparing systems with the test against those without, in terms of those outcomes. Incremental value can also be measured in units of outcome per incremental unit of resource (for example, money or human capacity). Using a novel, simplified model of tuberculosis transmission that addresses some of the limitations of earlier tuberculosis diagnostic models, we demonstrate that the incremental value of any novel test depends not just on its accuracy, but also on elements such as patient behaviour, tuberculosis natural history and health systems. By integrating these factors into a single unified framework, we advance an approach to the evaluation of new diagnostic tests for tuberculosis that considers the incremental value at the population level and demonstrates how additional data could inform more-effective implementation of tuberculosis diagnostic tests under various conditions.

  3. Monitoring of the Enzymatic Degradation of Protein Corona and Evaluating the Accompanying Cytotoxicity of Nanoparticles.

    PubMed

    Ma, Zhifang; Bai, Jing; Jiang, Xiue

    2015-08-19

    Established nanobio interactions face the challenge that the formation of nanoparticle-protein corona complexes shields the inherent properties of the nanoparticles and alters the manner of the interactions between nanoparticles and biological systems. Therefore, many studies have focused on protein corona-mediated nanoparticle binding, internalization, and intracellular transportation. However, there are a few studies to pay attention to if the corona encounters degradation after internalization and how the degradation of the protein corona affects cytotoxicity. To fill this gap, we prepared three types of off/on complexes based on gold nanoparticles (Au NPs) and dye-labeled serum proteins and studied the extracellular and intracellular proteolytic processes of protein coronas as well as their accompanying effects on cytotoxicity through multiple evaluation mechanisms, including cell viability, adenosine triphosphate (ATP) content, mitochondrial membrane potential (MMP), and reactive oxygen species (ROS). The proteolytic process was confirmed by recovery of the fluorescence of the dye-labeled protein molecules that was initially quenched by Au NPs. Our results indicate that the degradation rate of protein corona is dependent on the type of the protein based on systematical evaluation of the extracellular and intracellular degradation processes of the protein coronas formed by human serum albumin (HSA), γ-globulin (HGG), and serum fibrinogen (HSF). Degradation is the fastest for HSA corona and the slowest for HSF corona. Notably, we also find that the Au NP-HSA corona complex induces lower cell viability, slower ATP production, lower MMP, and higher ROS levels. The cytotoxicity of the nanoparticle-protein corona complex may be associated with the protein corona degradation process. All of these results will enrich the database of cytotoxicity induced by nanomaterial-protein corona complexes.

  4. Monitoring of the Enzymatic Degradation of Protein Corona and Evaluating the Accompanying Cytotoxicity of Nanoparticles.

    PubMed

    Ma, Zhifang; Bai, Jing; Jiang, Xiue

    2015-08-19

    Established nanobio interactions face the challenge that the formation of nanoparticle-protein corona complexes shields the inherent properties of the nanoparticles and alters the manner of the interactions between nanoparticles and biological systems. Therefore, many studies have focused on protein corona-mediated nanoparticle binding, internalization, and intracellular transportation. However, there are a few studies to pay attention to if the corona encounters degradation after internalization and how the degradation of the protein corona affects cytotoxicity. To fill this gap, we prepared three types of off/on complexes based on gold nanoparticles (Au NPs) and dye-labeled serum proteins and studied the extracellular and intracellular proteolytic processes of protein coronas as well as their accompanying effects on cytotoxicity through multiple evaluation mechanisms, including cell viability, adenosine triphosphate (ATP) content, mitochondrial membrane potential (MMP), and reactive oxygen species (ROS). The proteolytic process was confirmed by recovery of the fluorescence of the dye-labeled protein molecules that was initially quenched by Au NPs. Our results indicate that the degradation rate of protein corona is dependent on the type of the protein based on systematical evaluation of the extracellular and intracellular degradation processes of the protein coronas formed by human serum albumin (HSA), γ-globulin (HGG), and serum fibrinogen (HSF). Degradation is the fastest for HSA corona and the slowest for HSF corona. Notably, we also find that the Au NP-HSA corona complex induces lower cell viability, slower ATP production, lower MMP, and higher ROS levels. The cytotoxicity of the nanoparticle-protein corona complex may be associated with the protein corona degradation process. All of these results will enrich the database of cytotoxicity induced by nanomaterial-protein corona complexes. PMID:26200209

  5. THE CONNECTION OF TYPE II SPICULES TO THE CORONA

    SciTech Connect

    Judge, Philip G.; McIntosh, Scott W.; De Pontieu, Bart; Olluri, Kosovare

    2012-02-20

    We examine the hypothesis that plasma associated with 'Type II' spicules is heated to coronal temperatures, and that the upward moving hot plasma constitutes a significant mass supply to the solar corona. One-dimensional hydrodynamical models including time-dependent ionization are brought to bear on the problem. These calculations indicate that heating of field-aligned spicule flows should produce significant differential Doppler shifts between emission lines formed in the chromosphere, transition region, and corona. At present, observational evidence for the computed 60-90 km s{sup -1} differential shifts is weak, but the data are limited by difficulties in comparing the proper motion of Type II spicules with spectral and kinematic properties of an associated transition region and coronal emission lines. Future observations with the upcoming infrared interferometer spectrometer instrument should clarify if Doppler shifts are consistent with the dynamics modeled here.

  6. New Synoptic Maps of the Solar Corona from UVCS Observations

    NASA Astrophysics Data System (ADS)

    Strachan, L.; Panasyuk, A. V.; Miralles, M.; Kohl, J. L.; Baham, M.

    2005-05-01

    We present for the first time synoptic maps of the extended solar corona (r/Ro > 1.5) based on eight years of data from the SOHO Ultraviolet Coronagraph Spectrometer (UVCS). The data reveal the changes in the physical properties of the large scale features in the corona. Maps of O VI line intensities, line widths, and line ratios for the O VI 1032/1037 doublet and intensities and line widths for the H I Ly-alpha line reveal information about the evolution of coronal densities, temperatures, and outflow velocities over the solar cycle. In particular these data are used in support of program to understand the solar cycle variation of coronal holes and coronal streamers. This work is supported by NASA Grant NAG5-12781 to the Smithsonian Astrophysical Observatory and NASA subcontract OGSP21010200061SAO awarded to SAO through a grant to Southern Universty at Baton Rouge.

  7. The Structure and Dynamics of the Solar Corona

    NASA Technical Reports Server (NTRS)

    Mikic, Zoran

    2000-01-01

    This report covers technical progress during the third year of the NASA Space Physics Theory contract "The Structure and Dynamics of the Solar Corona," between NASA and Science Applications International Corporation, and covers the period June 16, 1998 to August 15, 1999. This is also the final report for this contract. Under this contract SAIC, the University of California, Irvine (UCI), and the Jet Propulsion Laboratory (JPL), have conducted research into theoretical modeling of active regions, the solar corona, and the inner heliosphere, using the MHD model. During the three-year duration of this contract we have published 49 articles in the scientific literature. These publications are listed in Section 3 of this report. In the Appendix we have attached reprints of selected articles. We summarize our progress during the third year of the contract. Full descriptions of our work can be found in the cited publications, a few of which are attached to this report.

  8. Corona method and apparatus for altering carbon containing compounds

    DOEpatents

    Sharma, Amit K.; Camaioni, Donald M.; Josephson, Gary B.

    1999-01-01

    The present invention is a method and apparatus for altering a carbon containing compound in an aqueous mixture. According to a first aspect of the present invention, it has been discovered that for an aqueous mixture having a carbon containing compound with an ozone reaction rate less than the ozone reaction rate of pentachlorophenol, use of corona discharge in a low or non-oxidizing atmosphere increases the rate of destruction of the carbon containing compound compared to corona discharge an oxidizing atmosphere. For an aqueous mixture containing pentachlorphenol, there was essentially no difference in destruction between atmospheres. According to a second aspect of the present invention, it has been further discovered that an aqueous mixture having a carbon containing compound in the presence of a catalyst and oxygen resulted in an increased destruction rate of the carbon containing compound compared to no catalyst.

  9. Corona Method And Apparatus For Altering Carbon Containing Compounds

    DOEpatents

    Sharma, Amit K.; Camaioni, Donald M.; Josephson; Gary B.

    2004-05-04

    The present invention is a method and apparatus for altering a carbon-containing compound in an aqueous mixture. According to a first aspect of the present invention, it has been discovered that for an aqueous mixture having a carbon containing compound with an ozone reaction rate less than the ozone reaction rate of pentachlorophenol, use of corona discharge in a low or non-oxidizing atmosphere increases the rate of destruction of the carbon containing compound compared to corona discharge an oxidizing atmosphere. For an aqueous mixture containing pentachlorphenol, there was essentially no difference in destruction between atmospheres. According to a second aspect of the present invention, it has been further discovered that an aqueous mixture having a carbon-containing compound in the presence of a catalyst and oxygen resulted in an increased destruction rate of the carbon containing compound compared to no catalyst.

  10. Heating of the Solar Corona and its Loops

    NASA Technical Reports Server (NTRS)

    Klimchuk, James A.

    2009-01-01

    At several million degrees, the solar corona is more than two orders of magnitude hotter than the underlying solar surface. The reason for these extreme conditions has been a puzzle for decades and is considered one of the fundamental problems in astrophysics. Much of the coronal plasma is organized by the magnetic field into arch-like structures called loops. Recent observational and theoretical advances have led to great progress in understanding the nature of these loops. In particular, we now believe they are bundles of unresolved magnetic strands that are heated by storms of impulsive energy bursts called nanoflares. Turbulent convection at the solar surface shuffles the footpoints of the strands and causes them to become tangled. A nanoflare occurs when the magnetic stresses reach a critical threshold, probably by way of a mechanism called the secondary instability. I will describe our current state of knowledge concerning the corona, its loops, and how they are heated.

  11. Measuring the IR solar corona during the 2017 eclipse

    NASA Astrophysics Data System (ADS)

    Bryans, Paul; Hannigan, James; Philip, Judge; Larson, Brandon; Sewell, Scott; McIntire, Lauren

    2016-05-01

    On 21 August 2017 a total solar eclipse will pass across the continental United States, offering a unique opportunity to conduct scientific research of the solar atmosphere. With the light from the Sun eclipsed, the solar corona becomes visible in a way not possible when swamped by the light from the photosphere. The infrared (IR) spectrum of the corona, in particular, is predicted to contain some of the most magnetically sensitive spectral lines. However, no comprehensive survey of this spectral range has been carried out to date. Here, we describe a Fourier Transform Spectrometer, currently under construction at NCAR, to measure the IR spectrum from 2 to 12 microns. We will discuss the operation of the experiment, which will be deployed along the path of totality in Wyoming, and the scientific results we hope to obtain.

  12. Aspects of nonlinear magnetohydrodynamics in the solar corona

    NASA Astrophysics Data System (ADS)

    Einaudi, G.; Rappazzo, A. F.; Velli, M.; Dahlburg, R. B.

    2004-04-01

    The solar corona is structured by the dynamics of plasmas and magnetic fields, which, at the global scales of coronal loops, prominences and helmet streamers may be described by magnetohydrodynamics. Here we will discuss the importance and role of nonlinear interactions both in the heating of the solar corona, which relies on the transfer, storage and dissipation of the mechanical energy present in photospheric motion, and in the acceleration of the slow solar wind above helmet streamers. In the first example, nonlinear interactions including the coupling of coronal magnetic fields to the velocity field and emerging flux through the photosphere determine both the rate of heating and the resulting coronal topology. In the second example, linear resistive instabilities in develop nonlinearly to accelerate plasmoids into the slow wind. Once plasmoids are generated, the melon-seed force due to the overall magnetic field radial gradients is followed using an Expanding Box Model.

  13. Coronas-F Orbit Monitoring and Re-Entry Prediction

    NASA Technical Reports Server (NTRS)

    Ivanov, N. M.; Kolyuka, Yu. F.; Afanasieva, T. I.; Gridchina, T. A.

    2007-01-01

    Russian scientific satellite CORONAS-F was launched on July, 31, 2001. The object was inserted in near-circular orbit with the inclination 82.5deg and a mean altitude approx. 520 km. Due to the upper atmosphere drag CORONAS-F was permanently descended and as a result on December, 6, 2005 it has finished the earth-orbital flight, having lifetime in space approx. 4.5 years. The satellite structural features and its flight attitude control led to the significant variations of its ballistic coefficient during the flight. It was a cause of some specific difficulties in the fulfillment of the ballistic and navigation support of this space vehicle flight. Besides the main mission objective CORONAS-F also has been selected by the Inter-Agency Space Debris Coordination Committee (IADC) as a target object for the next regular international re-entry test campaign on a program of surveillance and re-entry prediction for the hazard space objects within their de-orbiting phases. Spacecraft (S/C) CORONAS-F kept its working state right up to the end of the flight - down to the atmosphere entry. This fact enabled to realization of the additional research experiments, concerning with an estimation of the atmospheric density within the low earth orbits (LEO) of the artificial satellites, and made possible to continue track the S/C during final phase of its flight by means of Russian regular command & tracking system, used for it control. Thus there appeared a unique possibility of using for tracking S/C at its de-orbiting phase not only passive radar facilities, belonging to the space surveillance systems and traditionally used for support of the IADC re-entry test campaigns, but also more precise active trajectory radio-tracking facilities from the ground control complex (GCC) applied for this object. Under the corresponding decision of the Russian side such capability of additional high-precise tracking control of the CORONAS-F flight in this period of time has been implemented

  14. New Views of the Solar Corona from STEREO and SDO

    NASA Astrophysics Data System (ADS)

    Vourlidas, A.

    2012-01-01

    In the last few years, we have been treated to an unusual visual feast of solar observations of the corona in EUV wavelengths. The observations from the two vantage points of STEREO/SECCHI are now capturing the entire solar atmosphere simultaneously in four wavelengths. The SDO/AIA images provide us with arcsecond resolution images of the full visible disk in ten wavelengths. All these data are captured with cadences of a few seconds to a few minutes. In this talk, I review some intriguing results from our first attempts to deal with these observations which touch upon the problems of coronal mass ejection initiation and solar wind generation. I will also discuss data processing techniques that may help us recover even more information from the images. The talk will contain a generous portion of beautiful EUV images and movies of the solar corona.

  15. Detailed characteristics of intermittent current pulses due to positive corona

    SciTech Connect

    Liu, Yang Cui, Xiang; Lu, Tiebing; Wang, Zhenguo; Li, Xuebao; Xiang, Yu; Wang, Xiaobo

    2014-08-15

    In order to get detailed characteristics of intermittent current pulses due to positive corona such as the repetition rate of burst-pulse trains, the peak value ratio of the primary pulse to the secondary pulse, the number of pulses per burst, and the interval of the secondary pulses, a systematic study was carried out in a coaxial conductor-cylinder electrode system with the conductor electrode being set with a discharge point. Empirical formulae for the number of pulses per burst and the interval of the secondary pulses are first presented. A theoretical model based on the motion of the space-charge clouds is proposed. Analysis with the model gives explanations to the experimental results and reveals some new insights into the physical mechanism of positive intermittent corona.

  16. The degradation of organic dyes by corona discharge

    SciTech Connect

    Goheen, S.C.; McCulloch, M.; Durham, D.E.; Heath, W.O.

    1992-02-01

    Several dyes in water were individually exposed to corona discharge. Light absorbance decreased for all organic dyes with time. Absorbance losses with methylene blue, malachite green, and new coccine were studied. The loss of color was followed using an in situ colorimeter and the effects of varying the current, voltage, gas phase, stirring rates, salinity, and electrode spacing were investigated. The highest reaction rates were observed using the highest current, highest voltage (up to 10kV), highest stirring rate, lowest salinity, smallest electrode spacing, and an environment containing enhanced levels of oxygen. Current was higher in the presence of nitrogen than in the presence of oxygen (for the same voltage), but the reaction of methylene blue did not proceed unless oxygen was present. These results help identify conditions using corona discharge in which dyes, and potentially other organics, can be destroyed. 22 refs., 5 figs.

  17. Investigation of the corona current in a vacuum bulb

    NASA Astrophysics Data System (ADS)

    Chyhin, Vasyl

    2014-05-01

    The dependence of the negative corona current on the gas pressure was studied experimentally and theoretically in view of designing a gas-pressure sensor to be applied in the production of light bulbs. The gas pressure was varied in the range 1×10-2 Torr - 7.4×102 Torr. The dependence of the current on the gas pressure is characterized by a strong heterogeneity. This allowed the implementation of a prototype of a high-speed sensor for a wide range of gas pressures. A mathematical model was developed of the negative corona current behavior by taking into account the ionization of the gas molecules, the attachment and detachment of electrons, the charge drift and the surface ion-electron emission. The results of the numerical simulations describe satisfactorily the experimental dependences.

  18. Atmospheric response to Saharan dust deduced from ECMWF reanalysis increments

    NASA Astrophysics Data System (ADS)

    Kishcha, P.; Alpert, P.; Barkan, J.; Kirchner, I.; Machenhauer, B.

    2003-04-01

    This study focuses on the atmospheric temperature response to dust deduced from a new source of data - the European Reanalysis (ERA) increments. These increments are the systematic errors of global climate models, generated in reanalysis procedure. The model errors result not only from the lack of desert dust but also from a complex combination of many kinds of model errors. Over the Sahara desert the dust radiative effect is believed to be a predominant model defect which should significantly affect the increments. This dust effect was examined by considering correlation between the increments and remotely-sensed dust. Comparisons were made between April temporal variations of the ERA analysis increments and the variations of the Total Ozone Mapping Spectrometer aerosol index (AI) between 1979 and 1993. The distinctive structure was identified in the distribution of correlation composed of three nested areas with high positive correlation (> 0.5), low correlation, and high negative correlation (<-0.5). The innermost positive correlation area (PCA) is a large area near the center of the Sahara desert. For some local maxima inside this area the correlation even exceeds 0.8. The outermost negative correlation area (NCA) is not uniform. It consists of some areas over the eastern and western parts of North Africa with a relatively small amount of dust. Inside those areas both positive and negative high correlations exist at pressure levels ranging from 850 to 700 hPa, with the peak values near 775 hPa. Dust-forced heating (cooling) inside the PCA (NCA) is accompanied by changes in the static stability of the atmosphere above the dust layer. The reanalysis data of the European Center for Medium Range Weather Forecast(ECMWF) suggests that the PCA (NCA) corresponds mainly to anticyclonic (cyclonic) flow, negative (positive) vorticity, and downward (upward) airflow. These facts indicate an interaction between dust-forced heating /cooling and atmospheric circulation. The

  19. Method and apparatus for processing exhaust gas with corona discharge

    DOEpatents

    Barlow, Stephan E.; Orlando, Thomas M.; Tonkyn, Russell G.

    1999-01-01

    The present invention is placing a catalyst coating upon surfaces surrounding a volume containing corona discharge. In addition, the electrodes are coated with a robust dielectric material. Further, the electrodes are arranged so that at least a surface portion of each electrode extends into a flow path of the exhaust gas to be treated and there is only exhaust gas in the volume between each pair of electrodes.

  20. Method and apparatus for processing exhaust gas with corona discharge

    DOEpatents

    Barlow, S.E.; Orlando, T.M.; Tonkyn, R.G.

    1999-06-22

    The present invention is placing a catalyst coating upon surfaces surrounding a volume containing corona discharge. In addition, the electrodes are coated with a robust dielectric material. Further, the electrodes are arranged so that at least a surface portion of each electrode extends into a flow path of the exhaust gas to be treated and there is only exhaust gas in the volume between each pair of electrodes. 12 figs.

  1. Electrical Auxiliary Power Unit (EAPU) Corona Design Guideline. Revised

    NASA Technical Reports Server (NTRS)

    Hall, David K.; Kirkici, Hulya; Schweickart, Dan L.; Dunbar, William; Hillard, Barry

    2000-01-01

    This document is the result of a collaborative effort between NASA's Johnson Space Center, Marshall Space Flight Center, Glenn Research Center, and the United States Air Force Research Laboratory at Wright Patterson AFB in support of the Space Shuttle Orbiter Upgrades Program, specifically the Electric Auxiliary Power Unit Program. This document is intended as a guideline for design applications for corona and partial discharge avoidance and is not a requirements specification instrument.

  2. Mass and Energy Transfer Between the Solar Photosphere and Corona

    NASA Astrophysics Data System (ADS)

    Peter, H.

    2015-12-01

    The problem of chromospheric and coronal heating is also a problem of mass supply to the corona. On average we see redshifts at transition region temperatures of the order of 10 km/s. If interpreted as downflows, this would quickly empty the corona, and fresh material has to be transported into the corona. Several models have been proposed to understand this mass cycle between the different atmospheric layers. However, as of yet all these proposals have serious shortcomings. On the observational side open questions remain, too. With the new IRIS mission we can observe the transition region at unprecedented spatial and spectral resolution, but the observational results are still puzzling. In particular the finding that the spatial distribution of line widths and Doppler shifts do not change with increasing resolution is against physical intuition. This shows that even with IRIS we still have significant velocity gradients along the line-of-sight, indicating that shocks might play a significant role. Likewise the temporal evolution might be a key for our understanding of the mass cycle. It might well be that the filling and draining of hot plasma occurs on significantly different time scales, which might be part of the difficulty to arrive at a conclusive observational picture. Considering the progress made for the quiet Sun, it seems clear that the processes responsible for the mass exchange are not resolved (yet). Therefore one might wonder to what extent one could use larger and resolved individual events in more active parts of the Sun to understand the details of the mass transport. In particular a common understanding of reconnection events such as Ellerman bombs in the photosphere, explosive events in the transition region and the recently discovered IRIS bombs in-between might provide the key to better understand the mass cycle throughout the atmospheric layers from the photosphere to the corona.

  3. POLARIZATION OF THE THERMAL RADIO EMISSION FROM OUTER SOLAR CORONA

    SciTech Connect

    Sastry, Ch. V.

    2009-06-01

    The Haselgrove equations for radio-ray propagation in an anisotropic medium are used to determine the degree of circular polarization (dcp) of the low-frequency thermal radio emission from the outer solar corona with a magnetic field. The variation of dcp with frequency and magnetic field strength is investigated. It is found that weak magnetic fields can be detected by measuring the dcp at low frequencies.

  4. ESTIMATING THE ''DARK'' ENERGY CONTENT OF THE SOLAR CORONA

    SciTech Connect

    McIntosh, Scott W.; De Pontieu, Bart

    2012-12-20

    The discovery of ubiquitous low-frequency (3-5 mHz) Alfvenic waves in the solar chromosphere (with Hinode/Solar Optical Telescope) and corona (with CoMP and SDO) has provided some insight into the non-thermal energy content of the outer solar atmosphere. However, many questions remain about the true magnitude of the energy flux carried by these waves. Here we explore the apparent discrepancy in the resolved coronal Alfvenic wave amplitude ({approx}0.5 km s{sup -1}) measured by the Coronal Multi-channel Polarimeter (CoMP) compared to those of the Hinode and the Solar Dynamics Observatory (SDO) near the limb ({approx}20 km s{sup -1}). We use a blend of observational data and a simple forward model of Alfvenic wave propagation to resolve this discrepancy and determine the Alfvenic wave energy content of the corona. Our results indicate that enormous line-of-sight superposition within the coarse spatio-temporal sampling of CoMP hides the strong wave flux observed by Hinode and SDO and leads to the large non-thermal line broadening observed. While this scenario has been assumed in the past, our observations with CoMP of a strong correlation between the non-thermal line broadening with the low-amplitude, low-frequency Alfvenic waves observed in the corona provide the first direct evidence of a wave-related non-thermal line broadening. By reconciling the diverse measurements of Alfvenic waves, we establish large coronal non-thermal line widths as direct signatures of the hidden, or ''dark'', energy content in the corona and provide preliminary constraints on the energy content of the wave motions observed.

  5. OBSERVATION OF ULTRAFINE CHANNELS OF SOLAR CORONA HEATING

    SciTech Connect

    Ji, Haisheng; Cao, Wenda; Goode, Philip R.

    2012-05-01

    We report the first direct observations of dynamical events originating in the Sun's photosphere and subsequently lighting up the corona. Continuous small-scale, impulsive events have been tracked from their origin in the photosphere on through to their brightening of the local corona. We achieve this by combining high-resolution ground-based data from the 1.6 m aperture New Solar Telescope (NST) at Big Bear Solar Observatory (BBSO), and satellite data from the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamics Observatory (SDO). The NST imaging observations in helium I 10830 A reveal unexpected complexes of ultrafine, hot magnetic loops seen to be reaching from the photosphere to the base of the corona. Most of these ultrafine loops are characterized by an apparently constant, but surprisingly narrow diameter of about 100 km all along each loop, and the loops originate on the solar surface from intense, compact magnetic field elements. The NST observations detect the signature of upward injections of hot plasma that excite the ultrafine loops from the photosphere to the base of the corona. The ejecta have their individual footpoints in the intergranular lanes between the Sun's ubiquitous, convectively driven granules. In many cases, AIA/SDO detects cospatial and cotemporal brightenings in the overlying, million degree coronal loops in conjunction with the upward injections along the ultrafine loops. Segments of some of the more intense upward injections are seen as rapid blueshifted events in simultaneous H{alpha} blue wing images observed at BBSO. In sum, the observations unambiguously show impulsive coronal heating events from upward energy flows originating from intergranular lanes on the solar surface accompanied by cospatial mass flows.

  6. Numerical Simulations of Helicity Condensation in the Solar Corona

    NASA Astrophysics Data System (ADS)

    Zhao, L.; DeVore, C. R.; Antiochos, S. K.; Zurbuchen, T. H.

    2015-05-01

    The helicity condensation model has been proposed by Antiochos to explain the observed smoothness of coronal loops and the observed buildup of magnetic shear at filament channels. The basic hypothesis of the model is that magnetic reconnection in the corona causes the magnetic stress injected by photospheric motions to collect only at those special locations where prominences are observed to form. In this work we present the first detailed quantitative MHD simulations of the reconnection evolution proposed by the helicity condensation model. We use the well-known ansatz of modeling the closed corona as an initially uniform field between two horizontal photospheric plates. The system is driven by applying photospheric rotational flows that inject magnetic helicity into the corona. The flows are confined to a finite region on the photosphere so as to mimic the finite flux system of a bipolar active region, for example. The calculations demonstrate that, contrary to common belief, opposite helicity twists do not lead to significant reconnection in such a coronal system, whereas twists with the same sense of helicity do produce substantial reconnection. Furthermore, we find that for a given amount of helicity injected into the corona, the evolution of the magnetic shear is insensitive to whether the pattern of driving photospheric motions is fixed or quasi-random. In all cases, the shear propagates via reconnection to the boundary of the flow region while the total magnetic helicity is conserved, as predicted by the model. We discuss the implications of our results for solar observations and for future, more realistic simulations of the helicity condensation process.

  7. The Structure and Dynamics of the Solar Corona

    NASA Technical Reports Server (NTRS)

    Mikic, Zoran

    1998-01-01

    Under this contract SAIC, the University of California, Irvine (UCI), and the Jet Propulsion Laboratory (JPL), have conducted research into theoretical modeling of active regions, the solar corona, and the inner heliosphere, using the MHD model. During the period covered by this report we have published 17 articles in the scientific literature. These publications are listed in Section 4 of this report. In the Appendix we have attached reprints of selected articles.

  8. Intentional formation of a protein corona on nanoparticles: Serum concentration affects protein corona mass, surface charge, and nanoparticle-cell interaction.

    PubMed

    Gräfe, Christine; Weidner, Andreas; Lühe, Moritz V D; Bergemann, Christian; Schacher, Felix H; Clement, Joachim H; Dutz, Silvio

    2016-06-01

    The protein corona, which immediately is formed after contact of nanoparticles and biological systems, plays a crucial role for the biological fate of nanoparticles. In the here presented study we describe a strategy to control the amount of corona proteins which bind on particle surface and the impact of such a protein corona on particle-cell interactions. For corona formation, polyethyleneimine (PEI) coated magnetic nanoparticles (MNP) were incubated in a medium consisting of fetal calf serum (FCS) and cell culture medium. To modulate the amount of proteins bind to particles, the composition of the incubation medium was varied with regard to the FCS content. The protein corona mass was estimated and the size distribution of the participating proteins was determined by means of sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). Additionally, the zeta potential of incubated particles was measured. Human blood-brain barrier-representing cell line HBMEC was used for in vitro incubation experiments. To investigate the consequences of the FCS dependent protein corona formation on the interaction of MNP and cells flow cytometry and laser scanning microscopy were used. Zeta potential as well as SDS-PAGE clearly reveal an increase in the amount of corona proteins on MNP with increasing amount of FCS in incubation medium. For MNP incubated with lower FCS concentrations especially medium-sized proteins of molecular weights between 30kDa and 100kDa could be found within the protein corona, whereas for MNP incubated within higher FCS concentrations the fraction of corona proteins of 30kDa and less increased. The presence of the protein corona reduces the interaction of PEI-coated MNP with HBMEC cells within a 30min-incubation.

  9. Numerical Simulations of Helicity Condensation in the Solar Corona

    NASA Technical Reports Server (NTRS)

    Zhao, L.; DeVore, C. R.; Antiochos, S. K.; Zurbuchen, T. H.

    2015-01-01

    The helicity condensation model has been proposed by Antiochos (2013) to explain the observed smoothness of coronal loops and the observed buildup of magnetic shear at filament channels. The basic hypothesis of the model is that magnetic reconnection in the corona causes the magnetic stress injected by photospheric motions to collect only at those special locations where prominences form. In this work we present the first detailed quantitative MHD simulations of the reconnection evolution proposed by the helicity condensation model. We use the well-known ansatz of modeling the closed corona as an initially uniform field between two horizontal photospheric plates. The system is driven by applying photospheric rotational flows that inject magnetic helicity into the system. The flows are confined to a finite region on the photosphere so as to mimic the finite flux system of, for example, a bipolar active region. The calculations demonstrate that, contrary to common belief, coronal loops having opposite helicity do not reconnect, whereas loops having the same sense of helicity do reconnect. Furthermore, we find that for a given amount of helicity injected into the corona, the evolution of the magnetic shear is insensitive to whether the pattern of driving photospheric motions is fixed or quasi-random. In all cases, the shear propagates via reconnection to the boundary of the flow region while the total magnetic helicity is conserved, as predicted by the model. We discuss the implications of our results for solar observations and for future, more realistic simulations of the helicity condensation process.

  10. The biomolecular corona of nanoparticles in circulating biological media.

    PubMed

    Pozzi, D; Caracciolo, G; Digiacomo, L; Colapicchioni, V; Palchetti, S; Capriotti, A L; Cavaliere, C; Zenezini Chiozzi, R; Puglisi, A; Laganà, A

    2015-09-01

    When nanoparticles come into contact with biological media, they are covered by a biomolecular 'corona', which confers a new identity to the particles. In all the studies reported so far nanoparticles are incubated with isolated plasma or serum that are used as a model for protein adsorption. Anyway, bodily fluids are dynamic in nature so the question arises on whether the incubation protocol, i.e. dynamic vs. static incubation, could affect the composition and structure of the biomolecular corona. Here we let multicomponent liposomes interact with fetal bovine serum (FBS) both statically and dynamically, i.e. in contact with circulating FBS (≈40 cm s(-1)). The structure and composition of the liposome-protein corona, as determined by dynamic light scattering, electrophoretic light scattering and liquid chromatography tandem mass spectrometry, were found to be dependent on the incubation protocol. Specifically, following dynamic exposure to FBS, multicomponent liposomes were less enriched in complement proteins and appreciably more enriched in apolipoproteins and acute phase proteins (e.g. alpha-1-antitrypsin and inter-alpha-trypsin inhibitor heavy chain H3) that are involved in relevant interactions between nanoparticles and living systems. Supported by our results, we speculate that efficient predictive modeling of nanoparticle behavior in vivo will require accurate knowledge of nanoparticle-specific protein fingerprints in circulating biological media.

  11. Manifestations of electric currents observed in the K-corona

    NASA Astrophysics Data System (ADS)

    Kim, I. S.; Popov, V. V.

    2015-12-01

    The 2D distribution of tangential velocities of the coronal plasma electron component (K-corona) was obtained and interpreted. Coronal continuum linear polarization films in the green spectral range obtained during the total solar eclipse of March 29, 2006, are used. The developed method of high-precision linear polarimetry made it possible to obtain the first 2D distribution in the K-corona linear polarimetry history for the polarization angle sign at distances smaller than 1.5 Rsun. For clarity, we accepted that clockwise deviations of the polarization direction from tangential to the solar limb have positive polarity, whereas counterclockwise deviations have negative polarity. The distribution differs from the anticipated pattern for scattering by resting electrons and reveals a correlation with the coronal structure and the presence of diffuse and structural components and largeand small-scale regions of opposite polarities. The interpretation in the scope of scattering by moving electrons indicates that free electron tangential velocities (tangential electric currents) are strongly fragmented in the inner corona.

  12. Formation and Investigation of Corona Charged Films from Polylactic Acid

    NASA Astrophysics Data System (ADS)

    Gencheva, E. A.; Yovcheva, T. A.; Marudova, M. G.; Viraneva, A. P.; Bodurov, I. P.; Mekishev, G. A.; Sainov, S. H.

    2010-01-01

    The aim of the present work is the development of technology for formation of corona charged electret films from polylactic acid and investigation of their structural, optical and electret properties. Polylactide films with different degree of crystalinity were prepared by casting of poly-L-lactide and poly-DL lactide blended solutions. Then glass transition, crystallization and melting temperatures, as well as the crystalinity degree were determined by a differential scanning calorimetry. The charging of the samples in a corona discharge was carried out by means of a conventional corona triode system. Sample surface potential was measured by the method of the vibrating electrode with compensation. The time dependences of the sample surface potential under room conditions were studied for 50 days. The effect of lower pressure on the surface potential of charged samples was investigated. It was established that the reduced pressure leaded to the surface potential decay of the PLA electrets. The same effect was earlier observed for other polymer films. The optical characteristics—surface refractive index and optical dispersion, were determined by the method of the disappearing diffraction pattern using a laser refractometer.

  13. THE CYCLING OF MATERIAL BETWEEN THE SOLAR CORONA AND CHROMOSPHERE

    SciTech Connect

    Guerreiro, N.; Hansteen, Viggo; De Pontieu, B.

    2013-05-20

    Observations of transition region emission lines reveal the presence of redshifts in lines formed from the top of the chromosphere up to temperatures of about 2.5 Multiplication-Sign 10{sup 5} K and blueshifts for temperatures above that. However, it is doubtful that the apparent large downward flows in the lower transition region represents an emptying of the corona, so some mechanism must be responsible for maintaining the mass balance between the corona and the lower atmospheric layers. We use a three-dimensional magnetohydrodynamics code to study the cycling of mass between the corona, transition region, and chromosphere by adding a tracer fluid to the simulation in various temperature intervals in the transition region. We find that most of the material seen in transition region emission lines formed at temperatures below 3 Multiplication-Sign 10{sup 5} K is material that has been rapidly heated from chromospheric temperatures and thereafter is pushed down as it cools. This implies that the bulk of transition region material resides in small loops. In these loops, the density is high and radiative cooling is efficient.

  14. Power calculation of linear and angular incremental encoders

    NASA Astrophysics Data System (ADS)

    Prokofev, Aleksandr V.; Timofeev, Aleksandr N.; Mednikov, Sergey V.; Sycheva, Elena A.

    2016-04-01

    Automation technology is constantly expanding its role in improving the efficiency of manufacturing and testing processes in all branches of industry. More than ever before, the mechanical movements of linear slides, rotary tables, robot arms, actuators, etc. are numerically controlled. Linear and angular incremental photoelectric encoders measure mechanical motion and transmit the measured values back to the control unit. The capabilities of these systems are undergoing continual development in terms of their resolution, accuracy and reliability, their measuring ranges, and maximum speeds. This article discusses the method of power calculation of linear and angular incremental photoelectric encoders, to find the optimum parameters for its components, such as light emitters, photo-detectors, linear and angular scales, optical components etc. It analyzes methods and devices that permit high resolutions in the order of 0.001 mm or 0.001°, as well as large measuring lengths of over 100 mm. In linear and angular incremental photoelectric encoders optical beam is usually formulated by a condenser lens passes through the measuring unit changes its value depending on the movement of a scanning head or measuring raster. Past light beam is converting into an electrical signal by the photo-detecter's block for processing in the electrical block. Therefore, for calculating the energy source is a value of the desired value of the optical signal at the input of the photo-detecter's block, which reliably recorded and processed in the electronic unit of linear and angular incremental optoelectronic encoders. Automation technology is constantly expanding its role in improving the efficiency of manufacturing and testing processes in all branches of industry. More than ever before, the mechanical movements of linear slides, rotary tables, robot arms, actuators, etc. are numerically controlled. Linear and angular incremental photoelectric encoders measure mechanical motion and

  15. Remote plunger removal device for small-scale incremental pressing

    SciTech Connect

    Burnside, N.J.; Son, S.F.; Asay, B.W.

    1997-09-01

    Small-scale pressing of high explosives (HE) at Los Alamos National Laboratory (LANL) and elsewhere is routinely performed using pneumatic presses. Blast shields provide protection to the operator during the pressing procedure, but safety of the operator is a concern during removal of the plunger, which is currently performed manually. To minimize this risk, very high tolerances between the plunger and the die are required. These tolerances are often very costly, especially in the case of long, relatively narrow dies. The safety issue is an even greater concern with incremental pressing in which cleaning the die between increments is difficult or impossible. To better protect press operators, a device has been designed and constructed to allow remote plunger removal in a standard HE press. In this report the authors describe this modified press that allows remote removal of the plunger.

  16. The Space Station decision - Incremental politics and technological choice

    NASA Technical Reports Server (NTRS)

    Mccurdy, Howard E.

    1990-01-01

    Using primary documents and interviews with participants, this book describes the events that led up to the 1984 decision that NASA should build a permanently occupied, international space station in low earth orbit. The role that civil servants in NASA played in initiating the program is highlighted. The trail of the Space Station proposal as its advocates devised strategies to push it through the White House policy review process is followed. The critical analysis focuses on the way in which 'incrementalism' (the tendency of policy makers to introduce incremental changes once projects are under way) operated in connection with the Space Station program. The book calls for a commitment to a long-range space policy.

  17. The Role of Chemically Depleted Mantle in the Formation of Coronae on Venus

    NASA Technical Reports Server (NTRS)

    Smrekar, S. E.

    1995-01-01

    Without extensive plate subduction to act as a recycling mechanism, a thick layer of buoyant, depleted mantle material may accumulate beneath the thermal lithosphere on Venus due to the pressure-release melting that occurs during crustal formation. Such a layer could be the key factor that allows coronae to form on Venus but not on Earth. Coronae are roughly circular volcano-tectonic features that are interpreted as a manifestation of small-scale upwelling and are unique to Venus. The topographic expression of coronae is highly variable, ranging from domes to plateaus, with or without moats or single or multiple outer rises. In addition to why coronae from on Venus but not on Earth, two outstanding questions in the study of coronae are how the full range of topographic profiles are produced and the relationship between topography and the annulus of fractures that characterize coronae.

  18. Current-voltage characteristics of dc corona discharges in air between coaxial cylinders

    SciTech Connect

    Zheng, Yuesheng; Zhang, Bo He, Jinliang

    2015-02-15

    This paper presents the experimental measurement and numerical analysis of the current-voltage characteristics of dc corona discharges in air between coaxial cylinders. The current-voltage characteristics for both positive and negative corona discharges were measured within a specially designed corona cage. Then the measured results were fitted by different empirical formulae and analyzed by the fluid model. The current-voltage characteristics between coaxial cylinders can be expressed as I = C(U − U{sub 0}){sup m}, where m is within the range 1.5–2.0, which is similar to the point-plane electrode system. The ionization region has no significant effect on the current-voltage characteristic under a low corona current, while it will affect the distribution for the negative corona under a high corona current. The surface onset fields and ion mobilities were emphatically discussed.

  19. High-cadence observations of CME initiation and plasma dynamics in the corona with TESIS on board CORONAS-Photon

    NASA Astrophysics Data System (ADS)

    Bogachev, Sergey; Kuzin, Sergey; Zhitnik, I. A.; Bugaenko, O. I.; Goncharov, A. L.; Ignatyev, A. P.; Krutov, V. V.; Lomkova, V. M.; Mitrofanov, A. V.; Nasonkina, T. P.; Oparin, S. N.; Petzov, A. A.; Shestov, S. V.; Slemzin, V. A.; Soloviev, V. A.; Suhodrev, N. K.; Shergina, T. A.

    The TESIS is an ensemble of space instruments designed in Lebedev Institute of Russian Academy of Sciences for spectroscopic and imaging investigation of the Sun in EUV and soft X-ray spectral range with high spatial, temporal and spectral resolution. From 2009 January, when TESIS was launched onboard the Coronas-Photon satellite, it provided about 200 000 new images and spectra of the Sun, obtained during one of the deepest solar minimum in last century. Because of the wide field of view (4 solar radii) and high sensitivity, TESIS provided high-quality data on the origin and dynamics of eruptive prominences and CMEs in the low and intermediate solar corona. TESIS is also the first EUV instrument which provided high-cadence observations of coronal bright points and solar spicules with temporal resolution of a few seconds. We present first results of TESIS observations and discuss them from a scientific point of view.

  20. External Device to Incrementally Skid the Habitat (E-DISH)

    NASA Technical Reports Server (NTRS)

    Brazell, J. W.; Introne, Steve; Bedell, Lisa; Credle, Ben; Holp, Graham; Ly, Siao; Tait, Terry

    1994-01-01

    A Mars habitat transport system was designed as part of the NASA Mars exploration program. The transport system, the External Device to Incrementally Skid the Habitat (E - DISH), will be used to transport Mars habitats from their landing sites to the colony base and will be detached after unloading. The system requirements for Mars were calculated and scaled for model purposes. Specific model materials are commonly found and recommendations for materials for the Mars design are included.

  1. Metabolic parameters for ramp versus step incremental cycle ergometer tests.

    PubMed

    Zuniga, Jorge M; Housh, Terry J; Camic, Clayton L; Bergstrom, Haley C; Traylor, Daniel A; Schmidt, Richard J; Johnson, Glen O

    2012-12-01

    The purpose of this study was to examine mean differences and the patterns of responses for oxygen uptake ([Formula: see text]O(2)), heart rate (HR), and rating of perceived exertion (RPE) for ramp (15 W·min(-1)) versus step (30 W increments every 2 min) incremental cycle ergometer tests. Fourteen subjects (age and body mass of 23.2 ± 3.1 (mean ± SD ) years and 71.1 ± 10.1 kg, respectively) visited the laboratory on separate occasions. Two-way repeated measures ANOVAs with appropriate follow-up procedures, as well as paired t tests, were used to analyze the data. In addition, polynomial regression analyses were used to determine the patterns of responses for each dependent variable for the ramp and step tests. The ramp protocol resulted in lower mean [Formula: see text]O(2) and HR values at the common power outputs than the step protocol with no differences in RPE. The increased amount of work performed during the step (total work = 75.83 kJ) versus ramp (total work = 65.60 kJ) tests at the common power outputs may have contributed to the greater [Formula: see text]O(2) and HR values. The polynomial regression analyses showed that most subjects had the same patterns of responses for the ramp and step incremental tests for HR (86%) and RPE (93%) but different patterns for [Formula: see text]O(2) (71%). The findings from the present study suggested that the protocol selection for an incremental cycle ergometer test can affect the mean values for [Formula: see text]O(2) and HR, as well as the [Formula: see text]O(2) - power output relationship.

  2. International Space Station Increment-2 Microgravity Environment Summary Report

    NASA Technical Reports Server (NTRS)

    Jules, Kenol; Hrovat, Kenneth; Kelly, Eric; McPherson, Kevin; Reckart, Timothy

    2002-01-01

    This summary report presents the results of some of the processed acceleration data, collected aboard the International Space Station during the period of May to August 2001, the Increment-2 phase of the station. Two accelerometer systems were used to measure the acceleration levels during activities that took place during the Increment-2 segment. However, not all of the activities were analyzed for this report due to time constraints, lack of precise information regarding some payload operations and other station activities. The National Aeronautics and Space Administration sponsors the Microgravity Acceleration Measurement System and the Space Acceleration Microgravity System to support microgravity science experiments, which require microgravity acceleration measurements. On April 19, 2001, both the Microgravity Acceleration Measurement System and the Space Acceleration Measurement System units were launched on STS-100 from the Kennedy Space Center for installation on the International Space Station. The Microgravity Acceleration Measurement System unit was flown to the station in support of science experiments requiring quasi-steady acceleration measurements, while the Space Acceleration Measurement System unit was flown to support experiments requiring vibratory acceleration measurement. Both acceleration systems are also used in support of vehicle microgravity requirements verification. The International Space Station Increment-2 reduced gravity environment analysis presented in this report uses acceleration data collected by both sets of accelerometer systems: 1) The Microgravity Acceleration Measurement System, which consists of two sensors: the Orbital Acceleration Research Experiment Sensor Subsystem, a low frequency range sensor (up to 1 Hz), is used to characterize the quasi-steady environment for payloads and the vehicle, and the High Resolution Accelerometer Package, which is used to characterize the vibratory environment up to 100 Hz. 2) The Space

  3. Observers for Systems with Nonlinearities Satisfying an Incremental Quadratic Inequality

    NASA Technical Reports Server (NTRS)

    Acikmese, Ahmet Behcet; Corless, Martin

    2004-01-01

    We consider the problem of state estimation for nonlinear time-varying systems whose nonlinearities satisfy an incremental quadratic inequality. These observer results unifies earlier results in the literature; and extend it to some additional classes of nonlinearities. Observers are presented which guarantee that the state estimation error exponentially converges to zero. Observer design involves solving linear matrix inequalities for the observer gain matrices. Results are illustrated by application to a simple model of an underwater.

  4. Incremental learning for ν-Support Vector Regression.

    PubMed

    Gu, Bin; Sheng, Victor S; Wang, Zhijie; Ho, Derek; Osman, Said; Li, Shuo

    2015-07-01

    The ν-Support Vector Regression (ν-SVR) is an effective regression learning algorithm, which has the advantage of using a parameter ν on controlling the number of support vectors and adjusting the width of the tube automatically. However, compared to ν-Support Vector Classification (ν-SVC) (Schölkopf et al., 2000), ν-SVR introduces an additional linear term into its objective function. Thus, directly applying the accurate on-line ν-SVC algorithm (AONSVM) to ν-SVR will not generate an effective initial solution. It is the main challenge to design an incremental ν-SVR learning algorithm. To overcome this challenge, we propose a special procedure called initial adjustments in this paper. This procedure adjusts the weights of ν-SVC based on the Karush-Kuhn-Tucker (KKT) conditions to prepare an initial solution for the incremental learning. Combining the initial adjustments with the two steps of AONSVM produces an exact and effective incremental ν-SVR learning algorithm (INSVR). Theoretical analysis has proven the existence of the three key inverse matrices, which are the cornerstones of the three steps of INSVR (including the initial adjustments), respectively. The experiments on benchmark datasets demonstrate that INSVR can avoid the infeasible updating paths as far as possible, and successfully converges to the optimal solution. The results also show that INSVR is faster than batch ν-SVR algorithms with both cold and warm starts.

  5. Early ventilation-heart rate breakpoint during incremental cycling exercise.

    PubMed

    Gravier, G; Delliaux, S; Ba, A; Delpierre, S; Guieu, R; Jammes, Y

    2014-03-01

    Previous observations having reported a transient hypoxia at the onset of incremental exercise, we investigated the existence of concomitant ventilatory and heart rate (HR) breakpoints.33 subjects executed a maximal cycling exercise with averaging for successive 5-s periods of HR, ventilation, tidal volume (VT), mean inspiratory flow rate (VT/Ti), and end-tidal partial pressures of O2 (PETO2) and CO2. In 10 subjects, the transcutaneous partial pressure of O2 (PtcO2) was recorded and the venous blood lactic acid (LA) concentration measured.At the beginning of exercise, PETO2 decreased, reaching a nadir, then progressively increased until the exercise ended. PtcO2 varied in parallel. Whether or not a 0-W cycling period preceded the incremental exercise, the rate of changes in VE, VT, VT/Ti and HR significantly increased when the nadir PO2 was reached. The ventilatory/ HR breakpoint was measured at 33±4% of VO2max, whereas the ventilatory threshold (VTh) was detected at 67±4% of VO2max and LA began to increase at 45 to 50% of VO2max.During incremental cycling exercise, we identified the existence of HR and ventilatory breakpoints in advance of both lactate and ventilatory thresholds which coincided with modest hypoxia and hypercapnia.

  6. An Enhanced Visualization Process Model for Incremental Visualization.

    PubMed

    Schulz, Hans-Jorg; Angelini, Marco; Santucci, Giuseppe; Schumann, Heidrun

    2016-07-01

    With today's technical possibilities, a stable visualization scenario can no longer be assumed as a matter of course, as underlying data and targeted display setup are much more in flux than in traditional scenarios. Incremental visualization approaches are a means to address this challenge, as they permit the user to interact with, steer, and change the visualization at intermediate time points and not just after it has been completed. In this paper, we put forward a model for incremental visualizations that is based on the established Data State Reference Model, but extends it in ways to also represent partitioned data and visualization operators to facilitate intermediate visualization updates. In combination, partitioned data and operators can be used independently and in combination to strike tailored compromises between output quality, shown data quantity, and responsiveness-i.e., frame rates. We showcase the new expressive power of this model by discussing the opportunities and challenges of incremental visualization in general and its usage in a real world scenario in particular.

  7. Anaerobic Threshold and Salivary α-amylase during Incremental Exercise.

    PubMed

    Akizuki, Kazunori; Yazaki, Syouichirou; Echizenya, Yuki; Ohashi, Yukari

    2014-07-01

    [Purpose] The purpose of this study was to clarify the validity of salivary α-amylase as a method of quickly estimating anaerobic threshold and to establish the relationship between salivary α-amylase and double-product breakpoint in order to create a way to adjust exercise intensity to a safe and effective range. [Subjects and Methods] Eleven healthy young adults performed an incremental exercise test using a cycle ergometer. During the incremental exercise test, oxygen consumption, carbon dioxide production, and ventilatory equivalent were measured using a breath-by-breath gas analyzer. Systolic blood pressure and heart rate were measured to calculate the double product, from which double-product breakpoint was determined. Salivary α-amylase was measured to calculate the salivary threshold. [Results] One-way ANOVA revealed no significant differences among workloads at the anaerobic threshold, double-product breakpoint, and salivary threshold. Significant correlations were found between anaerobic threshold and salivary threshold and between anaerobic threshold and double-product breakpoint. [Conclusion] As a method for estimating anaerobic threshold, salivary threshold was as good as or better than determination of double-product breakpoint because the correlation between anaerobic threshold and salivary threshold was higher than the correlation between anaerobic threshold and double-product breakpoint. Therefore, salivary threshold is a useful index of anaerobic threshold during an incremental workload.

  8. An incremental strategy for calculating consistent discrete CFD sensitivity derivatives

    NASA Technical Reports Server (NTRS)

    Korivi, Vamshi Mohan; Taylor, Arthur C., III; Newman, Perry A.; Hou, Gene W.; Jones, Henry E.

    1992-01-01

    In this preliminary study involving advanced computational fluid dynamic (CFD) codes, an incremental formulation, also known as the 'delta' or 'correction' form, is presented for solving the very large sparse systems of linear equations which are associated with aerodynamic sensitivity analysis. For typical problems in 2D, a direct solution method can be applied to these linear equations which are associated with aerodynamic sensitivity analysis. For typical problems in 2D, a direct solution method can be applied to these linear equations in either the standard or the incremental form, in which case the two are equivalent. Iterative methods appear to be needed for future 3D applications; however, because direct solver methods require much more computer memory than is currently available. Iterative methods for solving these equations in the standard form result in certain difficulties, such as ill-conditioning of the coefficient matrix, which can be overcome when these equations are cast in the incremental form; these and other benefits are discussed. The methodology is successfully implemented and tested in 2D using an upwind, cell-centered, finite volume formulation applied to the thin-layer Navier-Stokes equations. Results are presented for two laminar sample problems: (1) transonic flow through a double-throat nozzle; and (2) flow over an isolated airfoil.

  9. Incremental validity of emotional intelligence ability in predicting academic achievement.

    PubMed

    Lanciano, Tiziana; Curci, Antonietta

    2014-01-01

    We tested the incremental validity of an ability measure of emotional intelligence (El) in predicting academic achievement in undergraduate students, controlling for cognitive abilities and personality traits. Academic achievement has been conceptualized in terms of the number of exams, grade point average, and study time taken to prepare for each exam. Additionally, gender differences were taken into account in these relationships. Participants filled in the Mayer-Salovey-Caruso Emotional Intelligence Test (MSCEIT), the Raven's Advanced Progressive Matrices, the reduced version of the Eysenck Personality Questionnaire, and academic achievement measures. Results showed that El abilities were positively related to academic achievement indices, such as the number of exams and grade point average; total El ability and the Perceiving branch were negatively associated with the study time spent preparing for exams. Furthermore, El ability adds a percentage of incremental variance with respect to cognitive ability and personality variables in explaining scholastic success. The magnitude of the associations between El abilities and academic achievement measures was generally higher for men than for women. Jointly considered, the present findings support the incremental validity of the MSCEIT and provide positive indications of the importance of El in students' academic development. The helpfulness of El training in the context of academic institutions is discussed. PMID:25603581

  10. Incremental Support Vector Machine Framework for Visual Sensor Networks

    NASA Astrophysics Data System (ADS)

    Awad, Mariette; Jiang, Xianhua; Motai, Yuichi

    2006-12-01

    Motivated by the emerging requirements of surveillance networks, we present in this paper an incremental multiclassification support vector machine (SVM) technique as a new framework for action classification based on real-time multivideo collected by homogeneous sites. The technique is based on an adaptation of least square SVM (LS-SVM) formulation but extends beyond the static image-based learning of current SVM methodologies. In applying the technique, an initial supervised offline learning phase is followed by a visual behavior data acquisition and an online learning phase during which the cluster head performs an ensemble of model aggregations based on the sensor nodes inputs. The cluster head then selectively switches on designated sensor nodes for future incremental learning. Combining sensor data offers an improvement over single camera sensing especially when the latter has an occluded view of the target object. The optimization involved alleviates the burdens of power consumption and communication bandwidth requirements. The resulting misclassification error rate, the iterative error reduction rate of the proposed incremental learning, and the decision fusion technique prove its validity when applied to visual sensor networks. Furthermore, the enabled online learning allows an adaptive domain knowledge insertion and offers the advantage of reducing both the model training time and the information storage requirements of the overall system which makes it even more attractive for distributed sensor networks communication.

  11. Climate response among growth increments of fish and trees

    USGS Publications Warehouse

    Guyette, R.P.; Rabeni, C.F.

    1995-01-01

    Significant correlations were found among the annual growth increments of stream fish, trees, and climate variables in the Ozark region of the United States. The variation in annual growth increments of rock bass (Ambloplites rupestris) from the Jacks Fork River was significantly correlated over 22 years with the ring width of four tree species: white oak (Quercus alba), post oak (Quercus stellata), shortleaf pine (Pinus echinata) and eastern red cedar (Juniperus virginiana). Rock bass growth and tree growth were both significantly correlated with July rainfall and stream discharge. Variations in annual growth of smallmouth bass (Micropterus dolomieu) from four streams were significantly correlated over 29 years (1939-1968) with mean May maximum air temperature but not with tree growth. The magnitude and significance of correlations among growth increments from fish and trees imply that conditions such as topography, stream gradient, organism age, and the distribution of a population relative to its geographic range can influence the climatic response of an organism. The timing and intensity of climatic variables may produce different responses among closely related species.

  12. Synthesis and Structure of Corona[6](het)arenes Containing Mixed Bridge Units.

    PubMed

    Fu, Zhan-Da; Guo, Qing-Hui; Zhao, Liang; Wang, De-Xian; Wang, Mei-Xiang

    2016-06-01

    A one-pot nucleophilic aromatic substitution reaction of 3,6-dichlorotetrazine with various diphenols and dibenzenethiols produced corona[4]arene[2]tetrazines that contain mixed oxygen, sulfide, methylene, and sulfone linkages. Macrocyclic ring transformations employing an inverse-electron-demand Diels-Alder reaction of tetrazine moieties with enamines and the subsequent sulfide oxidation reaction afforded diverse corona[4]arene[2]pyridazines. The acquired corona[6]arenes adopted three types of conformational structures in the crystalline state. PMID:27182609

  13. Acute kidney failure

    MedlinePlus

    Kidney failure; Renal failure; Renal failure - acute; ARF; Kidney injury - acute ... There are many possible causes of kidney damage. They include: ... cholesterol (cholesterol emboli) Decreased blood flow due to very ...

  14. What Is Heart Failure?

    MedlinePlus

    ... page from the NHLBI on Twitter. What Is Heart Failure? Heart failure is a condition in which the heart can' ... force. Some people have both problems. The term "heart failure" doesn't mean that your heart has stopped ...

  15. Impact of protein pre-coating on the protein corona composition and nanoparticle cellular uptake.

    PubMed

    Mirshafiee, Vahid; Kim, Raehyun; Park, Soyun; Mahmoudi, Morteza; Kraft, Mary L

    2016-01-01

    Nanoparticles (NPs) are functionalized with targeting ligands to enable selectively delivering drugs to desired locations in the body. When these functionalized NPs enter the blood stream, plasma proteins bind to their surfaces, forming a protein corona that affects NP uptake and targeting efficiency. To address this problem, new strategies for directing the formation of a protein corona that has targeting capabilities are emerging. Here, we have investigated the feasibility of directing corona composition to promote targeted NP uptake by specific types of cells. We used the well-characterized process of opsonin-induced phagocytosis by macrophages as a simplified model of corona-mediated NP uptake by a desired cell type. We demonstrate that pre-coating silica NPs with gamma-globulins (γ-globulins) produced a protein corona that was enriched with opsonins, such as immunoglobulins. Although immunoglobulins are ligands that bind to receptors on macrophages and elicit phagocytois, the opsonin-rich protein corona did not increase NP uptake by macrophage RAW 264.7 cells. Immunolabeling experiments indicated that the binding of opsonins to their target cell surface receptors was impeded by other proteins in the corona. Thus, corona-mediated NP targeting strategies must optimize both the recruitment of the desired plasma proteins as well as their accessibility and orientation in the corona layer.

  16. International Space Station Increment-2 Quick Look Report

    NASA Technical Reports Server (NTRS)

    Jules, Kenol; Hrovat, Kenneth; Kelly, Eric

    2001-01-01

    The objective of this quick look report is to disseminate the International Space Station (ISS) Increment-2 reduced gravity environment preliminary analysis in a timely manner to the microgravity scientific community. This report is a quick look at the processed acceleration data collected by the Microgravity Acceleration Measurement System (MAMS) during the period of May 3 to June 8, 2001. The report is by no means an exhaustive examination of all the relevant activities, which occurred during the time span mentioned above for two reasons. First, the time span being considered in this report is rather short since the MAMS was not active throughout the time span being considered to allow a detailed characterization. Second, as the name of the report implied, it is a quick look at the acceleration data. Consequently, a more comprehensive report, the ISS Increment-2 report, will be published following the conclusion of the Increment-2 tour of duty. NASA sponsors the MAMS and the Space Acceleration Microgravity System (SAMS) to support microgravity science experiments, which require microgravity acceleration measurements. On April 19, 2001, both the MAMS and the SAMS units were launched on STS-100 from the Kennedy Space Center for installation on the ISS. The MAMS unit was flown to the station in support of science experiments requiring quasisteady acceleration data measurements, while the SAMS unit was flown to support experiments requiring vibratory acceleration data measurement. Both acceleration systems are also used in support of the vehicle microgravity requirements verification. The ISS reduced gravity environment analysis presented in this report uses mostly the MAMS acceleration data measurements (the Increment-2 report will cover both systems). The MAMS has two sensors. The MAMS Orbital Acceleration Research Experiment Sensor Subsystem, which is a low frequency range sensor (up to 1 Hz), is used to characterize the quasi-steady environment for payloads and

  17. Heart failure - medicines

    MedlinePlus

    CHF - medicines; Congestive heart failure - medicines; Cardiomyopathy - medicines; HF - medicines ... You will need to take most of your heart failure medicines every day. Some medicines are taken ...

  18. Single Point Incremental Forming to increase material knowledge and production flexibility

    NASA Astrophysics Data System (ADS)

    Habraken, A. M.

    2016-08-01

    Nowadays, manufactured pieces can be divided into two groups: mass production and production of low volume number of parts. Within the second group (prototyping or small batch production), an emerging solution relies on Incremental Sheet Forming or ISF. ISF refers to processes where the plastic deformation occurs by repeated contact with a relatively small tool. More specifically, many publications over the past decade investigate Single Point Incremental Forming (SPIF) where the final shape is determined only by the tool movement. This manufacturing process is characterized by the forming of sheets by means of a CNC controlled generic tool stylus, with the sheets clamped by means of a non-workpiece-specific clamping system and in absence of a partial or a full die. The advantage is no tooling requirements and often enhanced formability, however it poses a challenge in term of process control and accuracy assurance. Note that the most commonly used materials in incremental forming are aluminum and steel alloys however other alloys are also used especially for medical industry applications, such as cobalt and chromium alloys, stainless steel and titanium alloys. Some scientists have applied incremental forming on PVC plates and other on sandwich panels composed of propylene with mild steel and aluminum metallic foams with aluminum sheet metal. Micro incremental forming of thin foils has also been developed. Starting from the scattering of the results of Finite Element (FE) simulations, when one tries to predict the tool force (see SPIF benchmark of 2014 Numisheet conference), we will see how SPIF and even micro SPIF (process applied on thin metallic sheet with a few grains within the thickness) allow investigating the material behavior. This lecture will focus on the identification of constitutive laws, on the SPIF forming mechanisms and formability as well as the failure mechanism. Different hypotheses have been proposed to explain SPIF formability, they will be

  19. 40 CFR 60.2595 - What if I do not meet an increment of progress?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... or Before November 30, 1999 Model Rule-Increments of Progress § 60.2595 What if I do not meet an... Administrator postmarked within 10 business days after the date for that increment of progress in table 1...

  20. Evaluation of incremental reactivity and its uncertainty in Southern California.

    PubMed

    Martien, Philip T; Harley, Robert A; Milford, Jana B; Russell, Armistead G

    2003-04-15

    The incremental reactivity (IR) and relative incremental reactivity (RIR) of carbon monoxide and 30 individual volatile organic compounds (VOC) were estimated for the South Coast Air Basin using two photochemical air quality models: a 3-D, grid-based model and a vertically resolved trajectory model. Both models include an extended version of the SAPRC99 chemical mechanism. For the 3-D modeling, the decoupled direct method (DDM-3D) was used to assess reactivities. The trajectory model was applied to estimate uncertainties in reactivities due to uncertainties in chemical rate parameters, deposition parameters, and emission rates using Monte Carlo analysis with Latin hypercube sampling. For most VOC, RIRs were found to be consistent in rankings with those produced by Carter using a box model. However, 3-D simulations show that coastal regions, upwind of most of the emissions, have comparatively low IR but higher RIR than predicted by box models for C4-C5 alkenes and carbonyls that initiate the production of HOx radicals. Biogenic VOC emissions were found to have a lower RIR than predicted by box model estimates, because emissions of these VOC were mostly downwind of the areas of primary ozone production. Uncertainties in RIR of individual VOC were found to be dominated by uncertainties in the rate parameters of their primary oxidation reactions. The coefficient of variation (COV) of most RIR values ranged from 20% to 30%, whereas the COV of absolute incremental reactivity ranged from about 30% to 40%. In general, uncertainty and variability both decreased when relative rather than absolute reactivity metrics were used.

  1. Evaluation of incremental reactivity and its uncertainty in Southern California.

    PubMed

    Martien, Philip T; Harley, Robert A; Milford, Jana B; Russell, Armistead G

    2003-04-15

    The incremental reactivity (IR) and relative incremental reactivity (RIR) of carbon monoxide and 30 individual volatile organic compounds (VOC) were estimated for the South Coast Air Basin using two photochemical air quality models: a 3-D, grid-based model and a vertically resolved trajectory model. Both models include an extended version of the SAPRC99 chemical mechanism. For the 3-D modeling, the decoupled direct method (DDM-3D) was used to assess reactivities. The trajectory model was applied to estimate uncertainties in reactivities due to uncertainties in chemical rate parameters, deposition parameters, and emission rates using Monte Carlo analysis with Latin hypercube sampling. For most VOC, RIRs were found to be consistent in rankings with those produced by Carter using a box model. However, 3-D simulations show that coastal regions, upwind of most of the emissions, have comparatively low IR but higher RIR than predicted by box models for C4-C5 alkenes and carbonyls that initiate the production of HOx radicals. Biogenic VOC emissions were found to have a lower RIR than predicted by box model estimates, because emissions of these VOC were mostly downwind of the areas of primary ozone production. Uncertainties in RIR of individual VOC were found to be dominated by uncertainties in the rate parameters of their primary oxidation reactions. The coefficient of variation (COV) of most RIR values ranged from 20% to 30%, whereas the COV of absolute incremental reactivity ranged from about 30% to 40%. In general, uncertainty and variability both decreased when relative rather than absolute reactivity metrics were used. PMID:12731843

  2. International Space Station Increment-3 Microgravity Environment Summary Report

    NASA Technical Reports Server (NTRS)

    Jules, Kenol; Hrovat, Kenneth; Kelly, Eric; McPherson, Kevin; Reckart, Timothy; Grodsinksy, Carlos

    2002-01-01

    This summary report presents the results of some of the processed acceleration data measured aboard the International Space Station during the period of August to December 2001. Two accelerometer systems were used to measure the acceleration levels for the activities that took place during Increment-3. However, not all of the activities were analyzed for this report due to time constraint and lack of precise timeline information regarding some payload operations and station activities. The National Aeronautics and Space Administration sponsors the Microgravity Acceleration Measurement System and the Space Acceleration Microgravity System to support microgravity science experiments which require microgravity acceleration measurements. On April 19, 2001, both the Microgravity Acceleration Measurement System and the Space Acceleration Measurement System units were launched on STS-100 from the Kennedy Space Center for installation on the International Space Station. The Microgravity Acceleration Measurement System unit was flown to the station in support of science experiments requiring quasi-steady acceleration measurements, while the Space Acceleration Measurement System unit was flown to support experiments requiring vibratory acceleration measurement. Both acceleration systems are also used in support of the vehicle microgravity requirements verification. The International Space Station Increment-3 reduced gravity environment analysis presented in this report uses acceleration data collected by both sets of accelerometer systems: (1) The Microgravity Acceleration Measurement System, which consists of two sensors: the Orbital Acceleration Research Experiment Sensor Subsystem, a low frequency range sensor (up to 1 Hz), is used to characterize the quasi-steady environment for payloads and vehicle, and the High Resolution Accelerometer Package, which is used to characterize the vibratory environment up to 100 Hz. (2) The Space Acceleration Measurement System, which is

  3. Vortex focusing of ions produced in corona discharge.

    PubMed

    Kolomiets, Yuri N; Pervukhin, Viktor V

    2013-06-15

    Completeness of the ion transportation into an analytical path defines the efficiency of ionization analysis techniques. This is of particular importance for atmospheric pressure ionization sources like corona discharge, electrospray, ionization with radioactive ((3)H, (63)Ni) isotopes that produce nonuniform spatial distribution of sample ions. The available methods of sample ion focusing are either efficient at reduced pressure (~1Torr) or feature high sample losses. This paper deals with experimental research into atmospheric pressure focusing of unipolar (positive) ions using a highly swirled air stream with a well-defined vortex core. Effects of electrical fields from corona needle and inlet capillary of mass spectrometer on collection efficiency is considered. We used a corona discharge to produce an ionized unipolar sample. It is shown experimentally that with an electrical field barrier efficient transportation and focusing of an ionized sample are possible only when a metal plate restricting the stream and provided with an opening covered with a grid is used. This gives a five-fold increase of the transportation efficiency. It is shown that the electric field barrier in the vortex sampling region reduces the efficiency of remote ionized sample transportation two times. The difference in the efficiency of light ion focusing observed may be explained by a high mobility and a significant effect of the electric field barrier upon them. It is possible to conclude based on the experimental data that the presence of the field barrier narrows considerably (more than by one and half) the region of the vortex sample ion focusing. PMID:23618173

  4. Observational capabilities of solar satellite "Coronas-Photon"

    NASA Astrophysics Data System (ADS)

    Kotov, Yu.

    Coronas-Photon mission is the third satellite of the Russian Coronas program on solar activity observation The main goal of the Coronas-Photon is the study of solar hard electromagnetic radiation in the wide energy range from UV up to high energy gamma-radiation sim 2000MeV Scientific payload for solar radiation observation consists of three type of instruments 1 monitors Natalya-2M Konus-RF RT-2 Penguin-M BRM Phoka Sphin-X Sokol for spectral and timing measurements of full solar disk radiation with timing in flare burst mode up to one msec Instruments Natalya-2M Konus-RF RT-2 will cover the wide energy range of hard X-rays and soft Gamma rays 15keV to 2000MeV and will together constitute the largest area detectors ever used for solar observations Detectors of gamma-ray monitors are based on structured inorganic scintillators with energy resolution sim 5 for nuclear gamma-line band to 35 for GeV-band PSD analysis is used for gamma neutron separation for solar neutron registration T 30MeV Penguin-M has capability to measure linear polarization of hard X-rays using azimuth are measured by Compton scattering asymmetry in case of polarization of an incident flux For X-ray and EUV monitors the scintillation phoswich detectors gas proportional counter CZT assembly and Filter-covered Si-diodes are used 2 Telescope-spectrometer TESIS for imaging solar spectroscopy in X-rays with angular resolution up to 1 in three spectral lines and RT-2 CZT assembly of CZT

  5. Advanced Heart Failure

    MedlinePlus

    ... High Blood Pressure Tools & Resources Stroke More Advanced Heart Failure Updated:Oct 8,2015 When heart failure (HF) ... content was last reviewed on 04/06/2015. Heart Failure • Home • About Heart Failure • Causes and Risks for ...

  6. Nuclear cycler: An incremental approach to the deflection of asteroids

    NASA Astrophysics Data System (ADS)

    Vasile, Massimiliano; Thiry, Nicolas

    2016-04-01

    This paper introduces a novel deflection approach based on nuclear explosions: the nuclear cycler. The idea is to combine the effectiveness of nuclear explosions with the controllability and redundancy offered by slow push methods within an incremental deflection strategy. The paper will present an extended model for single nuclear stand-off explosions in the proximity of elongated ellipsoidal asteroids, and a family of natural formation orbits that allows the spacecraft to deploy multiple bombs while being shielded by the asteroid during the detonation.

  7. Intermittent versus Continuous Incremental Field Tests: Are Maximal Variables Interchangeable?

    PubMed

    Carminatti, Lorival J; Possamai, Carlos A P; de Moraes, Marcelo; da Silva, Juliano F; de Lucas, Ricardo D; Dittrich, Naiandra; Guglielmo, Luiz G A

    2013-01-01

    The aim of the present study was to compare physiological responses derived from an incremental progressive field test with a constant speed test i.e. intermittent versus continuous protocol. Two progressive maximum tests (Carminatti`s test (T-CAR) and the Vameval test (T-VAM)), characterized by increasing speed were used. T-CAR is an intermittent incremental test, performed as shuttle runs; while T-VAM is a continuous incremental test performed on an athletic track. Eighteen physically active, healthy young subjects (21.9 ± 2.0 years; 76.5 ± 8.6 kg, 1.78 ± 0.08 m, 11.2 ± 5.4% body fat), volunteered for this study. Subjects performed four different maximum test sessions conducted in the field: two incremental tests and two time to exhaustion tests (TTE) at peak test velocities (PV). No significant differences were found for PV (T-CAR = 15.6 ± 1.2; T-VAM = 15.5 ± 1.3 km·h(-1)) and maximal HR (T-CAR = 195 ± 11; T- VAM = 194 ± 14 bpm). During TTE, there were no significant differences for HR (TTET-CAR and TTET-VAM = 192 ± 12 bpm). However, there was a significant difference in TTE (p = 0.04) (TTET-CAR = 379 ± 84, TTET-VAM = 338 ± 58 s) with a low correlation (r = 0.41). The blood lactate concentration measured at the end of the TTE tests, showed no significant difference (TTET-CAR = 13.2 ± 2.4 vs. TTET-VAM = 12.9 ± 2.4 mmol·l(-1)). Based on the present findings, it is suggested that the maximal variables derived from T-CAR and T-VAM can be interchangeable in the design of training programs. Key pointsT-CAR is an intermittent shuttle run test that predicts the maximal aerobic speed with accuracy, hence, test results could be interchangeable with continuous straight-line tests.T-CAR provides valid field data for evaluating aerobic fitness.In comparison with T-VAM, T-CAR may be a more favourable way to prescribe intermittent training using a shuttle-running protocol.

  8. Gradual wavelet reconstruction of the velocity increments for turbulent wakes

    NASA Astrophysics Data System (ADS)

    Keylock, C. J.; Stresing, R.; Peinke, J.

    2015-02-01

    This work explores the properties of the velocity increment distributions for wakes of contrasting local Reynolds number and nature of generation (a cylinder wake and a multiscale-forced case, respectively). It makes use of a technique called gradual wavelet reconstruction (GWR) to generate constrained randomizations of the original data, the nature of which is a function of a parameter, ϑ. This controls the proportion of the energy between the Markov-Einstein length (˜ 0.8 Taylor scales) and integral scale that is fixed in place in the synthetic data. The properties of the increments for these synthetic data are then compared to the original data as a function of ϑ. We write a Fokker-Planck equation for the evolution of the velocity increments as a function of spatial scale, r, and, in line with previous work, expand the drift and diffusion terms in terms up to fourth order in the increments and find no terms are relevant beyond the quadratic terms. Only the linear contribution to the expansion of the drift coefficient is non-zero and it exhibits a consistent scaling with ϑ for different flows above a low threshold. For the diffusion coefficient, we find a local Reynolds number independence in the relation between the constant term and ϑ for the multiscale-forced wakes. This term characterizes small scale structure and can be contrasted with the results for the Kolmogorov capacity of the zero-crossings of the velocity signals, which measures structure over all scales and clearly distinguishes between the types of forcing. Using GWR shows that results for the linear and quadratic terms in the expansion of the diffusion coefficient are significant, providing a new means for identifying intermittency and anomalous scaling in turbulence datasets. All our data showed a similar scaling behavior for these parameters irrespective of forcing type or Reynolds number, indicating a degree of universality to the anomalous scaling of turbulence. Hence, these terms are a

  9. High-frequency incremental methods for electromagnetic complex source points

    NASA Astrophysics Data System (ADS)

    Canta, Stefano Mihai

    This dissertation advances knowledge in field-based High-Frequency (HF) incremental methods for electromagnetic Complex Source Points (CSP), and its most immediate impact is a significantly faster analysis and design of reflector antennas. HF incremental methods overcome many difficulties encountered in other ray-tracing techniques, mostly when crossing shadow boundaries in the electromagnetic (EM) field predictions. The combination of HF methods with CSPs allows to speed up EM computations. CSPs are obtained by locating real electric or magnetic dipole sources in complex space. EM field patterns are derived through analytical continuation of the geometrical quantities associated with the source position; the continuation provides an exact Maxwellian description of a Gaussian Beam. When CSPs are used as basis functions, they can represent any radiated field pattern. Then, by truncating negligible beams in the direction of observation, computations are sped up compared to a plane- or spherical-wave based expansion. Because of these facts, CSPs can be used with Physical Optics (PO) based HF methods for the efficient analysis of electrically large reflectors. However, PO does not always provide accurate field predictions, especially in regions of greatest shadowing or at grazing incidence. Therefore, I developed a HF Incremental Fringe Formulation (IFF) for CSPs to provide a correction term for PO that, when added to the total PO field, recovers an accurate estimate of the scattered field at the first asymptotic order. In addition, since PO does not have caustic problems, the new fringe asymptotic recovery is free of caustics for any geometrical configuration, too. Moreover, I also introduced a double diffraction formulation for CSPs, using the Incremental Theory of Diffraction, yielding simulation results very close to those obtained with a Method of Moments (MoM) approach. Unlike ray-based methods, no tracing in complex space is necessary, and no caustics are

  10. Comparison of the incremental and hierarchical methods for crystalline neon.

    PubMed

    Nolan, S J; Bygrave, P J; Allan, N L; Manby, F R

    2010-02-24

    We present a critical comparison of the incremental and hierarchical methods for the evaluation of the static cohesive energy of crystalline neon. Both of these schemes make it possible to apply the methods of molecular electronic structure theory to crystalline solids, offering a systematically improvable alternative to density functional theory. Results from both methods are compared with previous theoretical and experimental studies of solid neon and potential sources of error are discussed. We explore the similarities of the two methods and demonstrate how they may be used in tandem to study crystalline solids.

  11. The Development of Chromospheres & Coronae in the T Tauri Stars

    NASA Astrophysics Data System (ADS)

    Imhoff, Catherine L.

    The T Tauri stars represent a normal stage in the pre-main sequence evolution of solar-mass stars. Ultraviolet observations have revealed the presence of strong Mg II h and k lines, ultraviolet excesses, and far-ultraviolet emission lines indicative of dense, active chromospheres (Appenzeller and Wolf 1979, Appenzeller et al. 1980, Brown et al. 1981, Gahm et al. 1979, Giampapa et al. 1981, Gondhalekar et al. 1979, Imhoff and Giampapa 1980, 1981). The surface fluxes of the transition region lines equal and exceed those of any other late-type star (Imhoff and Giampapa 1980, 1981). However only about one third of the T Tauri stars have been detected by Einstein (Feigelson and DeCampli 1981, Gahm 1980, Walter and Kuhi 1981). The low X-ray flux, relative to the far-ultraviolet lines, in some of the stars may be due to absorption of the X-rays in dense gas shells (Gahm 1980, Walter and Kuhi 1981). On the other hand, a relative weakening of the higher temperature far-ultraviolet emission lines may signal that the T Tauri atmosphere does not reach coronal temperatures in those stars, perhaps due to higher chromospheric densities or to the effects of mass loss (Imhoff and Giampapa 1981, 1982). If there are indeed T Tauri stars with and without coronae, then we may be witnessing the birth of the corona sometime during the T Tauri stage. It would be of great interest to study the development of the chromosphere and corona during the evolution of a protostar and to detail the processes that affect its evolution. We propose to study this evolution through the T Tauri stage with IUE. We would like to observe a selection of X-ray bright and faint T Tauri stars. Concurrently we will perform ground-based scanner observations to obtain Ca II fluxes for these variable stars. We have chosen the targetted stars carefully on the basis of known surface temperatures, luminosities, extinction, distance, X-ray results, and vsini's. we wish to derive information on the density and

  12. Toxic Gas Removal by Dielectric Discharge with Corona Effect

    SciTech Connect

    Moreno, H.; Pacheco, M.; Mercado, A.; Cruz, A.; Pacheco, J.; Yousfi, M.; Eichwald, O.; Benhenni, M.

    2006-12-04

    In this work, a theoretical and experimental study on SO2 and NOx removal by non-thermal plasma technology, more specifically a dielectric barrier (DBD) discharge combined with the Corona effect, is presented. Results obtained from a theoretical study describe the chemical kinetic model of SO2 and NOx removal processes; the effect of OH radicals in removal of both gases is noteworthy. Experimental results of de-SO2 process are reported. Also, optical emission spectroscopy study was applied on some atomic helium lines to obtain temperature of electrons in the non-thermal plasma.

  13. The role of photoionization in negative corona discharge

    NASA Astrophysics Data System (ADS)

    Lu, B. X.; Sun, H. Y.

    2016-09-01

    The effect of photoionization on the negative corona discharge was simulated based on the needle to plane air gaps. The Trichel pulse, pulse train, electron density and the distribution of electric field will be discussed in this manuscript. Effect of photoionization on the magnitude and interval of the first pulse will be discussed for different applied voltages. It is demonstrated that the peak of the first pulse current could be weakened by photoionization and a critical voltage of the first pulse interval influenced by photoionization was given.

  14. Heating of the Solar Corona by Dissipative Alfven Solitons

    SciTech Connect

    Stasiewicz, K.

    2006-05-05

    Solar photospheric convection drives myriads of dissipative Alfven solitons (hereinafter called alfvenons) capable of accelerating electrons and ions to energies of hundreds of keV and producing the x-ray corona. Alfvenons are exact solutions of two-fluid equations for a collisionless plasma and represent natural accelerators for conversion of the electromagnetic energy flux driven by convective flows into kinetic energy of charged particles in space and astrophysical plasmas. Their properties have been experimentally verified in the magnetosphere, where they accelerate auroral electrons to tens of keV.

  15. The Structure and Dynamics of the Solar Corona

    NASA Technical Reports Server (NTRS)

    Mikic, Zoran

    1998-01-01

    This report covers technical progress during the first year of the NASA Space Physics Theory contract between NASA and Science Applications International Corporation. Under this contract SAIC, the University of California, Irvine (UCI), and the Jet Propulsion Laboratory (JPL), have conducted research into theoretical modeling of active regions, the solar corona, and the inner heliosphere, using the MHD model. During the period covered by this report we have published 26 articles in the scientific literature. These publications are listed in Section 4 of this report. In the Appendix we have attached reprints of selected articles.

  16. Toxic Gas Removal by Dielectric Discharge with Corona Effect

    NASA Astrophysics Data System (ADS)

    Moreno, H.; Pacheco, M.; Pacheco, J.; Mercado, A.; Cruz, A.; Yousfi, M.; Eichwald, O.; Benhenni, M.

    2006-12-01

    In this work, a theoretical and experimental study on SO2 and NOx removal by non-thermal plasma technology, more specifically a dielectric barrier (DBD) discharge combined with the Corona effect, is presented. Results obtained from a theoretical study describe the chemical kinetic model of SO2 and NOx removal processes; the effect of OH radicals in removal of both gases is noteworthy. Experimental results of de-SO2 process are reported. Also, optical emission spectroscopy study was applied on some atomic helium lines to obtain temperature of electrons in the non-thermal plasma.

  17. Remote Sensing Measurements of the Corona with the Solar Probe

    NASA Technical Reports Server (NTRS)

    Habbal, Shadia Rifai; Woo, Richard

    1996-01-01

    Remote sensing measurements of the solar corona are indespensible for the exploration of the source and acceleration regions of the solar wind which are inaccessible to in situ plasma, paritcles and field experiments.Furthermore, imaging the solar disk and coronal from the unique vantage point of the trajectory and the proximity of the Solar Probe spacecraft, will provide the first ever opportunity to explore the small scale structures within coronal holes and streamers from viewing angles and with spatial resolutions never attained before.

  18. Electron studies of acceleration processes in the corona. [solar probe mission planning

    NASA Technical Reports Server (NTRS)

    Lin, R. P.

    1978-01-01

    The solar probe mission can obtain unique and crucially important measurements of electron acceleration, storage, and propagation processes in the corona and can probe the magnetic field structure of the corona below the spacecraft. The various energetic electron phenomena which will be sampled by the Solar Probe are described and some new techniques to probe coronal structures are suggested.

  19. Subduction on the margins of coronae on Venus: Evidence from radiothermal emissivity measurements

    NASA Technical Reports Server (NTRS)

    Robinson, C. A.

    1993-01-01

    Retrograde subduction has been suggested to occur at three coronae on Venus: Latona, Artemis, and Eithinoha. Using the mineralogical arguments of Klose to explain surface emissivity, a study of radio thermal emissivity of Venus coronae showed that emissivity changes associated with Latona, Artemis, and Ceres imply the same crustal movements predicted by the subduction model of Sandwell and Schubert.

  20. CORONA DESTRUCTION: AN INNOVATIVE CONTROL TECHNOLOGY FOR VOCS AND AIR TOXICS

    EPA Science Inventory

    This paper discusses the work and results to date leading to the demonstration of the corona destruction process at pilot scale. The research effort in corona destruction of volatile organic compounds (VOCs) and air toxics has shown significant promise for providing a valuable co...

  1. Stealth effect of biomolecular corona on nanoparticle uptake by immune cells.

    PubMed

    Caracciolo, Giulio; Palchetti, Sara; Colapicchioni, Valentina; Digiacomo, Luca; Pozzi, Daniela; Capriotti, Anna Laura; La Barbera, Giorgia; Laganà, Aldo

    2015-10-01

    When injected in a biological milieu, a nanomaterial rapidly adsorbs biomolecules forming a biomolecular corona. The biomolecular corona changes the interfacial composition of a nanomaterial giving it a biological identity that determines the physiological response. Characterization of the biomolecular structure and composition has received increasing attention mostly due to its detrimental impact on the nanomaterial's metabolism in vivo. It is generally accepted that an opsonin-enriched biomolecular corona promotes immune system recognition and rapid clearance from circulation. Here we applied dynamic light scattering and nanoliquid chromatography tandem mass spectrometry to thoroughly characterize the biomolecular corona formed around lipid and silica nanoparticles (NPs). Incubation with human plasma resulted in the formation of NP-biomolecular coronas enriched with immunoglobulins, complement factors, and coagulation proteins that bind to surface receptors on immune cells and elicit phagocytosis. Conversely, we found that protein-coated NPs were protected from uptake by macrophage RAW 264.7 cells. This implies that the biomolecular corona formation provides a stealth effect on macrophage recognition. Our results suggest that correct prediction of the NP's fate in vivo will require more than just the knowledge of the biomolecular corona composition. Validation of efficient methods for mapping protein binding sites on the biomolecular corona of NPs is an urgent task for future research.

  2. 76 FR 3655 - Bunker Hill Groundwater Basin, Riverside-Corona Feeder Project, San Bernardino and Riverside...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-20

    ... of Intent (NOI) to prepare an Environmental Impact Statement on February 24, 2010 (75 FR 8395). The... Bureau of Reclamation Bunker Hill Groundwater Basin, Riverside-Corona Feeder Project, San Bernardino and.../DEIS) for the proposed Riverside-Corona Feeder (RCF) Project. Interested parties are invited to...

  3. Improving Targeting of Metal-Phenolic Capsules by the Presence of Protein Coronas.

    PubMed

    Ju, Yi; Dai, Qiong; Cui, Jiwei; Dai, Yunlu; Suma, Tomoya; Richardson, Joseph J; Caruso, Frank

    2016-09-01

    Particles adsorb proteins when they enter a physiological environment; this results in a surface coating termed a "protein corona". A protein corona can affect both the properties and functionalities of engineered particles. Here, we prepared hyaluronic acid (HA)-based capsules through the assembly of metal-phenolic networks (MPNs) and engineered their targeting ability in the absence and presence of protein coronas by varying the HA molecular weight. The targeting ability of the capsules was HA molecular weight dependent, and a high HA molecular weight (>50 kDa) was required for efficient targeting. The specific interactions between high molecular weight HA capsules and receptor-expressing cancer cells were negligibly affected by the presence of protein coronas, whereas nonspecific capsule-cell interactions were significantly reduced in the presence of a protein corona derived from human serum. Consequently, the targeting specificity of HA-based MPN capsules was enhanced due to the formation of a protein corona. This study highlights the significant and complex roles of a protein corona in biointeractions and demonstrates how protein coronas can be used to improve the targeting specificity of engineered particles. PMID:27560314

  4. Hybrid Modeling for Scenario-Based Evaluation of Failure Effects in Advanced Hardware-Software Designs

    NASA Technical Reports Server (NTRS)

    Malin, Jane T.; Fleming, Land; Throop, David

    2001-01-01

    This paper describes an incremental scenario-based simulation approach to evaluation of intelligent software for control and management of hardware systems. A hybrid continuous/discrete event simulation of the hardware dynamically interacts with the intelligent software in operations scenarios. Embedded anomalous conditions and failures in simulated hardware can lead to emergent software behavior and identification of missing or faulty software or hardware requirements. An approach is described for extending simulation-based automated incremental failure modes and effects analysis, to support concurrent evaluation of intelligent software and the hardware controlled by the software

  5. Utilizing the protein corona around silica nanoparticles for dual drug loading and release

    NASA Astrophysics Data System (ADS)

    Shahabi, Shakiba; Treccani, Laura; Dringen, Ralf; Rezwan, Kurosch

    2015-10-01

    A protein corona forms spontaneously around silica nanoparticles (SNPs) in serum-containing media. To test whether this protein corona can be utilized for the loading and release of anticancer drugs we incorporated the hydrophilic doxorubicin, the hydrophobic meloxicam as well as their combination in the corona around SNPs. The application of corona-covered SNPs to osteosarcoma cells revealed that drug-free particles did not affect the cell viability. In contrast, SNPs carrying a protein corona with doxorubicin or meloxicam lowered the cell proliferation in a concentration-dependent manner. In addition, these particles had an even greater antiproliferative potential than the respective concentrations of free drugs. The best antiproliferative effects were observed for SNPs containing both doxorubicin and meloxicam in their corona. Co-localization studies revealed the presence of doxorubicin fluorescence in the nucleus and lysosomes of cells exposed to doxorubicin-containing coated SNPs, suggesting that endocytotic uptake of the SNPs facilitates the cellular accumulation of the drug. Our data demonstrate that the protein corona, which spontaneously forms around nanoparticles, can be efficiently exploited for loading the particles with multiple drugs for therapeutic purposes. As drugs are efficiently released from such particles they may have a great potential for nanomedical applications.A protein corona forms spontaneously around silica nanoparticles (SNPs) in serum-containing media. To test whether this protein corona can be utilized for the loading and release of anticancer drugs we incorporated the hydrophilic doxorubicin, the hydrophobic meloxicam as well as their combination in the corona around SNPs. The application of corona-covered SNPs to osteosarcoma cells revealed that drug-free particles did not affect the cell viability. In contrast, SNPs carrying a protein corona with doxorubicin or meloxicam lowered the cell proliferation in a concentration

  6. Personalized disease-specific protein corona influences the therapeutic impact of graphene oxide

    NASA Astrophysics Data System (ADS)

    Hajipour, Mohammad Javad; Raheb, Jamshid; Akhavan, Omid; Arjmand, Sareh; Mashinchian, Omid; Rahman, Masoud; Abdolahad, Mohammad; Serpooshan, Vahid; Laurent, Sophie; Mahmoudi, Morteza

    2015-05-01

    The hard corona, the protein shell that is strongly attached to the surface of nano-objects in biological fluids, is recognized as the first layer that interacts with biological objects (e.g., cells and tissues). The decoration of the hard corona (i.e., the type, amount, and conformation of the attached proteins) can define the biological fate of the nanomaterial. Recent developments have revealed that corona decoration strongly depends on the type of disease in human patients from which the plasma is obtained as a protein source for corona formation (referred to as the `personalized protein corona'). In this study, we demonstrate that graphene oxide (GO) sheets can trigger different biological responses in the presence of coronas obtained from various types of diseases. GO sheets were incubated with plasma from human subjects with different diseases/conditions, including hypofibrinogenemia, blood cancer, thalassemia major, thalassemia minor, rheumatism, fauvism, hypercholesterolemia, diabetes, and pregnancy. Identical sheets coated with varying protein corona decorations exhibited significantly different cellular toxicity, apoptosis, and uptake, reactive oxygen species production, lipid peroxidation and nitrogen oxide levels. The results of this report will help researchers design efficient and safe, patient-specific nano biomaterials in a disease type-specific manner for clinical and biological applications.The hard corona, the protein shell that is strongly attached to the surface of nano-objects in biological fluids, is recognized as the first layer that interacts with biological objects (e.g., cells and tissues). The decoration of the hard corona (i.e., the type, amount, and conformation of the attached proteins) can define the biological fate of the nanomaterial. Recent developments have revealed that corona decoration strongly depends on the type of disease in human patients from which the plasma is obtained as a protein source for corona formation (referred

  7. Transformational adaptation when incremental adaptations to climate change are insufficient

    PubMed Central

    Kates, Robert W.; Travis, William R.; Wilbanks, Thomas J.

    2012-01-01

    All human–environment systems adapt to climate and its natural variation. Adaptation to human-induced change in climate has largely been envisioned as increments of these adaptations intended to avoid disruptions of systems at their current locations. In some places, for some systems, however, vulnerabilities and risks may be so sizeable that they require transformational rather than incremental adaptations. Three classes of transformational adaptations are those that are adopted at a much larger scale, that are truly new to a particular region or resource system, and that transform places and shift locations. We illustrate these with examples drawn from Africa, Europe, and North America. Two conditions set the stage for transformational adaptation to climate change: large vulnerability in certain regions, populations, or resource systems; and severe climate change that overwhelms even robust human use systems. However, anticipatory transformational adaptation may be difficult to implement because of uncertainties about climate change risks and adaptation benefits, the high costs of transformational actions, and institutional and behavioral actions that tend to maintain existing resource systems and policies. Implementing transformational adaptation requires effort to initiate it and then to sustain the effort over time. In initiating transformational adaptation focusing events and multiple stresses are important, combined with local leadership. In sustaining transformational adaptation, it seems likely that supportive social contexts and the availability of acceptable options and resources for actions are key enabling factors. Early steps would include incorporating transformation adaptation into risk management and initiating research to expand the menu of innovative transformational adaptations. PMID:22509036

  8. STS-102 Expedition 2 Increment and Science Briefing

    NASA Technical Reports Server (NTRS)

    2001-01-01

    Merri Sanchez, Expedition 2 Increment Manager, John Uri, Increment Scientist, and Lybrease Woodard, Lead Payload Operations Director, give an overview of the upcoming activities and objectives of the Expedition 2's (E2's) mission in this prelaunch press conference. Ms. Sanchez describes the crew rotation of Expedition 1 to E2, the timeline E2 will follow during their stay on the International Space Station (ISS), and the various flights going to the ISS and what each will bring to ISS. Mr. Uri gives details on the on-board experiments that will take place on the ISS in the fields of microgravity research, commercial, earth, life, and space sciences (such as radiation characterization, H-reflex, colloids formation and interaction, protein crystal growth, plant growth, fermentation in microgravity, etc.). He also gives details on the scientific facilities to be used (laboratory racks and equipment such as the human torso facsimile or 'phantom torso'). Ms. Woodard gives an overview of Marshall Flight Center's role in the mission. Computerized simulations show the installation of the Space Station Remote Manipulator System (SSRMS) onto the ISS and the installation of the airlock using SSRMS. Live footage shows the interior of the ISS, including crew living quarters, the Progress Module, and the Destiny Laboratory. The three then answer questions from the press.

  9. Polynomial-style region incremental multisecret image sharing

    NASA Astrophysics Data System (ADS)

    Wang, Ran-Zan; Lin, Yung-Yi

    2011-03-01

    This paper proposes a polynomial-style region incremental multisecret image sharing (PBRIMSIS), for sharing multiple secrets in an image among n participants. The method enables the dealer to distribute the content of an image S to multiple regions, where each region is associated with a certain level of secrecy. In the proposed n-level PBRIMSIS scheme, input image S is encoded to n+1 shadow images that exhibit the following features: a. each shadow image cannot reveal any region in S, b. any t (2 <= t <= n + 1) shadow images can be used to reveal these regions associated with up to t - 1 secret levels, and c. S can be completely reconstructed when all of the n+1 shadow images are available. A discrete cosine transform-based PBRIMSIS with a smaller shadow image scheme is designed to improve the transmission and storage of the generated shadow images. The property of incremental disclosure to the region-based secrets in an image is applicable to image sharing in diverse applications that require the sharing of multiple secrets with different secrecy priorities, such as in cooperative working or in military secrets.

  10. SAMS Acceleration Measurements on Mir (NASA Increment 4)

    NASA Technical Reports Server (NTRS)

    DeLombard, Richard

    1998-01-01

    During NASA Increment 4 (January to May 1997), about 5 gigabytes of acceleration data were collected by the Space Acceleration Measurements System (SAMS) onboard the Russian Space Station, Mir. The data were recorded on 28 optical disks which were returned to Earth on STS-84. During this increment, SAMS data were collected in the Priroda module to support the Mir Structural Dynamics Experiment (MiSDE), the Binary Colloidal Alloy Tests (BCAT), Angular Liquid Bridge (ALB), Candle Flames in Microgravity (CFM), Diffusion Controlled Apparatus Module (DCAM), Enhanced Dynamic Load Sensors (EDLS), Forced Flow Flame Spreading Test (FFFr), Liquid Metal Diffusion (LMD), Protein Crystal Growth in Dewar (PCG/Dewar), Queen's University Experiments in Liquid Diffusion (QUELD), and Technical Evaluation of MIM (TEM). This report points out some of the salient features of the microgravity environment to which these experiments were exposed. Also documented are mission events of interest such as the docked phase of STS-84 operations, a Progress engine bum, Soyuz vehicle docking and undocking, and Progress vehicle docking. This report presents an overview of the SAMS acceleration measurements recorded by 10 Hz and 100 Hz sensor heads. The analyses included herein complement those presented in previous summary reports prepared by the Principal Investigator Microgravity Services (PIMS) group.

  11. Transformational adaptation when incremental adaptations to climate change are insufficient.

    PubMed

    Kates, Robert W; Travis, William R; Wilbanks, Thomas J

    2012-05-01

    All human-environment systems adapt to climate and its natural variation. Adaptation to human-induced change in climate has largely been envisioned as increments of these adaptations intended to avoid disruptions of systems at their current locations. In some places, for some systems, however, vulnerabilities and risks may be so sizeable that they require transformational rather than incremental adaptations. Three classes of transformational adaptations are those that are adopted at a much larger scale, that are truly new to a particular region or resource system, and that transform places and shift locations. We illustrate these with examples drawn from Africa, Europe, and North America. Two conditions set the stage for transformational adaptation to climate change: large vulnerability in certain regions, populations, or resource systems; and severe climate change that overwhelms even robust human use systems. However, anticipatory transformational adaptation may be difficult to implement because of uncertainties about climate change risks and adaptation benefits, the high costs of transformational actions, and institutional and behavioral actions that tend to maintain existing resource systems and policies. Implementing transformational adaptation requires effort to initiate it and then to sustain the effort over time. In initiating transformational adaptation focusing events and multiple stresses are important, combined with local leadership. In sustaining transformational adaptation, it seems likely that supportive social contexts and the availability of acceptable options and resources for actions are key enabling factors. Early steps would include incorporating transformation adaptation into risk management and initiating research to expand the menu of innovative transformational adaptations.

  12. Health care reform? An American obsession with prescriptive incrementalism.

    PubMed

    Broyles, R W; Falcone, D J

    1996-01-01

    A rounded evaluation of the national health insurance proposals that now seem to be taken seriously by political elites requires conceptual organization. This article adopts a typology that describes each major proposal as a social, mixed or a private insurance scheme depending on the source(s) of funding, method of compensating hospitals and physicians, the unit of payment, and mechanism for financing capital. Not surprisingly, the analysis suggests that the social insurance model, closely resembling the Canadian system, is more likely to control inflation and redress distributional inequities than are other approaches. Why, then, has this approach not been adopted? The answer may be found in the widespread acceptance of disjointed incrementalism as a valid description of the policy process which yields an ideological orientation that can be termed "prescriptive incrementalism." This orientation is closely related to a belief in an "American exceptionalism," a belief that is not warranted by a cross-sectional examination of the political culture infusing issues about the proper role of government in health care financing and delivery. Unfortunately for advocates, the truly exceptional factor restricting the United States' ability to effect national health reform is a quite delberately obstruction-oriented political structure.

  13. Evaluation of the dimensional accuracy in single point incremental forming

    NASA Astrophysics Data System (ADS)

    Araújo, R.; Silva, M. B.; Montanari, L.; Teixeira, P.; Reis, A.; Martins, P. A. F.

    2013-12-01

    Incremental Sheet Forming (ISF) is a forming process widely used to obtain small batches or prototypes. By improving forming strategies, the process can be used in a wide range of applications. However, this technology still presents some drawbacks. The dimensional accuracy between the 3D CAD model and the final product is one of the key challenges for this technique. The springback phenomenon during the incremental forming process is an important reason for the lack of accuracy. In order to study the mechanism of this phenomenon, the geometry of the sheet metal was measured in two different stages of the conventional production chain. First, the geometry of the sheet metal part was acquired after the forming stage, without be released from the blank holder. Then, the final geometry was achieved after the cutting process from the original sheet. A 3D scanning system was used to measure and inspect the springback phenomenon of each step. A reverse method is proposed to design the new tool path for compensation of the springback.

  14. Incremental Knowledge Base Construction Using DeepDive

    PubMed Central

    Shin, Jaeho; Wu, Sen; Wang, Feiran; De Sa, Christopher; Zhang, Ce; Ré, Christopher

    2016-01-01

    Populating a database with unstructured information is a long-standing problem in industry and research that encompasses problems of extraction, cleaning, and integration. Recent names used for this problem include dealing with dark data and knowledge base construction (KBC). In this work, we describe DeepDive, a system that combines database and machine learning ideas to help develop KBC systems, and we present techniques to make the KBC process more efficient. We observe that the KBC process is iterative, and we develop techniques to incrementally produce inference results for KBC systems. We propose two methods for incremental inference, based respectively on sampling and variational techniques. We also study the tradeoff space of these methods and develop a simple rule-based optimizer. DeepDive includes all of these contributions, and we evaluate Deep-Dive on five KBC systems, showing that it can speed up KBC inference tasks by up to two orders of magnitude with negligible impact on quality. PMID:27144081

  15. Incremental Scheduling Engines for Human Exploration of the Cosmos

    NASA Technical Reports Server (NTRS)

    Jaap, John; Phillips, Shaun

    2005-01-01

    As humankind embarks on longer space missions farther from home, the requirements and environments for scheduling the activities performed on these missions are changing. As we begin to prepare for these missions it is appropriate to evaluate the merits and applicability of the different types of scheduling engines. Scheduling engines temporally arrange tasks onto a timeline so that all constraints and objectives are met and resources are not overbooked. Scheduling engines used to schedule space missions fall into three general categories: batch, mixed-initiative, and incremental. This paper presents an assessment of the engine types, a discussion of the impact of human exploration of the moon and Mars on planning and scheduling, and the applicability of the different types of scheduling engines. This paper will pursue the hypothesis that incremental scheduling engines may have a place in the new environment; they have the potential to reduce cost, to improve the satisfaction of those who execute or benefit from a particular timeline (the customers), and to allow astronauts to plan their own tasks and those of their companion robots.

  16. Incremental learning of skill collections based on intrinsic motivation.

    PubMed

    Metzen, Jan H; Kirchner, Frank

    2013-01-01

    Life-long learning of reusable, versatile skills is a key prerequisite for embodied agents that act in a complex, dynamic environment and are faced with different tasks over their lifetime. We address the question of how an agent can learn useful skills efficiently during a developmental period, i.e., when no task is imposed on him and no external reward signal is provided. Learning of skills in a developmental period needs to be incremental and self-motivated. We propose a new incremental, task-independent skill discovery approach that is suited for continuous domains. Furthermore, the agent learns specific skills based on intrinsic motivation mechanisms that determine on which skills learning is focused at a given point in time. We evaluate the approach in a reinforcement learning setup in two continuous domains with complex dynamics. We show that an intrinsically motivated, skill learning agent outperforms an agent which learns task solutions from scratch. Furthermore, we compare different intrinsic motivation mechanisms and how efficiently they make use of the agent's developmental period.

  17. Unsupervised fuzzy clustering using Weighted Incremental Neural Networks.

    PubMed

    Muhammed, Hamed Hamid

    2004-12-01

    A new more efficient variant of a recently developed algorithm for unsupervised fuzzy clustering is introduced. A Weighted Incremental Neural Network (WINN) is introduced and used for this purpose. The new approach is called FC-WINN (Fuzzy Clustering using WINN). The WINN algorithm produces a net of nodes connected by edges, which reflects and preserves the topology of the input data set. Additional weights, which are proportional to the local densities in input space, are associated with the resulting nodes and edges to store useful information about the topological relations in the given input data set. A fuzziness factor, proportional to the connectedness of the net, is introduced in the system. A watershed-like procedure is used to cluster the resulting net. The number of the resulting clusters is determined by this procedure. Only two parameters must be chosen by the user for the FC-WINN algorithm to determine the resolution and the connectedness of the net. Other parameters that must be specified are those which are necessary for the used incremental neural network, which is a modified version of the Growing Neural Gas algorithm (GNG). The FC-WINN algorithm is computationally efficient when compared to other approaches for clustering large high-dimensional data sets. PMID:15714603

  18. Incremental ECAP of thick continuous plates - machine and initial trials

    NASA Astrophysics Data System (ADS)

    Rosochowski, A.; Olejnik, L.

    2014-08-01

    Incremental ECAP (I-ECAP) can be used for SPD of continuous bars, plates and sheets. This paper describes design, construction and preliminary trials of a prototype machine capable of processing thick continuous plates. To increase productivity, a two-turn I-ECAP is used, which is equivalent to route C in conventional one-turn ECAP. The machine has a reciprocating punch inclined at 45°, a clamp holding the plate in the die during deformation and a feeder incrementally feeding the plate when it is not deformed; all these devices are driven by hydraulic actuators controlled by a PLC. The machine is capable of deforming materials at room temperature as well as elevated temperatures. The die is heated with electric heaters. The machine has also an integrated cooling system and a lubrication system. The material used for the initial trials was Al 1050 plate (10×50×1000) conversion coated with calcium aluminate and lubricated with dry soap. The process was carried out at room temperature using 1.6 mm feeding stroke and a low cycle frequency of approximately 0.2 Hz. The UFG structure after the first pass of the process revealed by STEM confirms process feasibility.

  19. Incremental theory of diffraction for complex point source illumination

    NASA Astrophysics Data System (ADS)

    Polemi, A.; Carluccio, G.; Albani, M.; Toccafondi, A.; Maci, S.

    2007-12-01

    The complex point source (CPS) is a solution of the Helmholtz equation obtained by analytical continuation of the free-space Green's function for complex position of the point source. The CPS representation of radiated fields can be used within a ray code to predict the interaction between an antenna and its actual environment, when standard diffraction formulations are extended to the CPS illumination. In the past, ray-based diffraction theories such as the geometrical theory of diffraction and its uniform version (UTD) were extended to complex point source fields, leaving, however, open some problematic issues concerning the "complex ray tracing". In this paper, the generalization of the incremental theory of diffraction (ITD) to CPS is formulated. The total field scattered by the object is given in terms of line integration along edge discontinuities of ITD diffraction coefficients plus the discontinuous geometrical optics (GO). An incremental form of the discontinuous GO is also proposed to overcome GO "complex ray tracing" difficulties. The final formulation is very simple and leads to accurate results that are successfully validated by comparison against a method of moment solution.

  20. Communication: Phase incremented echo train acquisition in NMR spectroscopy

    NASA Astrophysics Data System (ADS)

    Baltisberger, Jay H.; Walder, Brennan J.; Keeler, Eric G.; Kaseman, Derrick C.; Sanders, Kevin J.; Grandinetti, Philip J.

    2012-06-01

    We present an improved and general approach for implementing echo train acquisition (ETA) in magnetic resonance spectroscopy, particularly where the conventional approach of Carr-Purcell-Meiboom-Gill (CPMG) acquisition would produce numerous artifacts. Generally, adding ETA to any N-dimensional experiment creates an N + 1 dimensional experiment, with an additional dimension associated with the echo count, n, or an evolution time that is an integer multiple of the spacing between echo maxima. Here we present a modified approach, called phase incremented echo train acquisition (PIETA), where the phase of the mixing pulse and every other refocusing pulse, ϕP, is incremented as a single variable, creating an additional phase dimension in what becomes an N + 2 dimensional experiment. A Fourier transform with respect to the PIETA phase, ϕP, converts the ϕP dimension into a Δp dimension where desired signals can be easily separated from undesired coherence transfer pathway signals, thereby avoiding cumbersome or intractable phase cycling schemes where the receiver phase must follow a master equation. This simple modification eliminates numerous artifacts present in NMR experiments employing CPMG acquisition and allows "single-scan" measurements of transverse relaxation and J-couplings. Additionally, unlike CPMG, we show how PIETA can be appended to experiments with phase modulated signals after the mixing pulse.

  1. Incremental learning of concept drift in nonstationary environments.

    PubMed

    Elwell, Ryan; Polikar, Robi

    2011-10-01

    We introduce an ensemble of classifiers-based approach for incremental learning of concept drift, characterized by nonstationary environments (NSEs), where the underlying data distributions change over time. The proposed algorithm, named Learn(++). NSE, learns from consecutive batches of data without making any assumptions on the nature or rate of drift; it can learn from such environments that experience constant or variable rate of drift, addition or deletion of concept classes, as well as cyclical drift. The algorithm learns incrementally, as other members of the Learn(++) family of algorithms, that is, without requiring access to previously seen data. Learn(++). NSE trains one new classifier for each batch of data it receives, and combines these classifiers using a dynamically weighted majority voting. The novelty of the approach is in determining the voting weights, based on each classifier's time-adjusted accuracy on current and past environments. This approach allows the algorithm to recognize, and act accordingly, to the changes in underlying data distributions, as well as to a possible reoccurrence of an earlier distribution. We evaluate the algorithm on several synthetic datasets designed to simulate a variety of nonstationary environments, as well as a real-world weather prediction dataset. Comparisons with several other approaches are also included. Results indicate that Learn(++). NSE can track the changing environments very closely, regardless of the type of concept drift. To allow future use, comparison and benchmarking by interested researchers, we also release our data used in this paper.

  2. Incremental learning of skill collections based on intrinsic motivation

    PubMed Central

    Metzen, Jan H.; Kirchner, Frank

    2013-01-01

    Life-long learning of reusable, versatile skills is a key prerequisite for embodied agents that act in a complex, dynamic environment and are faced with different tasks over their lifetime. We address the question of how an agent can learn useful skills efficiently during a developmental period, i.e., when no task is imposed on him and no external reward signal is provided. Learning of skills in a developmental period needs to be incremental and self-motivated. We propose a new incremental, task-independent skill discovery approach that is suited for continuous domains. Furthermore, the agent learns specific skills based on intrinsic motivation mechanisms that determine on which skills learning is focused at a given point in time. We evaluate the approach in a reinforcement learning setup in two continuous domains with complex dynamics. We show that an intrinsically motivated, skill learning agent outperforms an agent which learns task solutions from scratch. Furthermore, we compare different intrinsic motivation mechanisms and how efficiently they make use of the agent's developmental period. PMID:23898265

  3. Incremental Aerodynamic Coefficient Database for the USA2

    NASA Technical Reports Server (NTRS)

    Richardson, Annie Catherine

    2016-01-01

    In March through May of 2016, a wind tunnel test was conducted by the Aerosciences Branch (EV33) to visually study the unsteady aerodynamic behavior over multiple transition geometries for the Universal Stage Adapter 2 (USA2) in the MSFC Aerodynamic Research Facility's Trisonic Wind Tunnel (TWT). The purpose of the test was to make a qualitative comparison of the transonic flow field in order to provide a recommended minimum transition radius for manufacturing. Additionally, 6 Degree of Freedom force and moment data for each configuration tested was acquired in order to determine the geometric effects on the longitudinal aerodynamic coefficients (Normal Force, Axial Force, and Pitching Moment). In order to make a quantitative comparison of the aerodynamic effects of the USA2 transition geometry, the aerodynamic coefficient data collected during the test was parsed and incorporated into a database for each USA2 configuration tested. An incremental aerodynamic coefficient database was then developed using the generated databases for each USA2 geometry as a function of Mach number and angle of attack. The final USA2 coefficient increments will be applied to the aerodynamic coefficients of the baseline geometry to adjust the Space Launch System (SLS) integrated launch vehicle force and moment database based on the transition geometry of the USA2.

  4. Incremental concept learning with few training examples and hierarchical classification

    NASA Astrophysics Data System (ADS)

    Bouma, Henri; Eendebak, Pieter T.; Schutte, Klamer; Azzopardi, George; Burghouts, Gertjan J.

    2015-10-01

    Object recognition and localization are important to automatically interpret video and allow better querying on its content. We propose a method for object localization that learns incrementally and addresses four key aspects. Firstly, we show that for certain applications, recognition is feasible with only a few training samples. Secondly, we show that novel objects can be added incrementally without retraining existing objects, which is important for fast interaction. Thirdly, we show that an unbalanced number of positive training samples leads to biased classifier scores that can be corrected by modifying weights. Fourthly, we show that the detector performance can deteriorate due to hard-negative mining for similar or closely related classes (e.g., for Barbie and dress, because the doll is wearing a dress). This can be solved by our hierarchical classification. We introduce a new dataset, which we call TOSO, and use it to demonstrate the effectiveness of the proposed method for the localization and recognition of multiple objects in images.

  5. Development of a positive corona from a long grounded wire in a growing thunderstorm field

    NASA Astrophysics Data System (ADS)

    Mokrov, M. S.; Raizer, Yu P.; Bazelyan, E. M.

    2013-11-01

    The properties of a non-stationary corona initiated from a long grounded wire suspended horizontally above the ground and coronating in a slowly varying thundercloud electric field are studied. A two-dimensional (2D) model of the corona is developed. On the basis of this model, characteristics of the corona produced by a lightning protection wire are calculated under thunderstorm conditions. The corona characteristics are also found by using approximate analytical and quasi-one-dimensional numerical models. The results of these models agree reasonably well with those obtained from the 2D simulation. This allows one to estimate the corona parameters without recourse to the cumbersome simulation. This work was performed with a view to study the efficiency of lightning protection wires later on.

  6. Solar wind Acceleration from the Upper Chromosphere to the Corona in Coronal Hole Regions

    NASA Technical Reports Server (NTRS)

    Esser, Ruth

    1998-01-01

    The dynamic behavior of the plasma in the chromosphere/transition region /inner corona is vital for the acceleration of the solar wind. With new theoretical descriptions of the solar atmosphere and corona, and the increased observational possibilities provided by the SOHO spacecraft, it is possible to conduct an integrated study of the solar atmosphere and corona using observational and theoretical approaches. Over the past few years a series of observational techniques have been used to estimate the solar wind densities, temperatures and flow speed in the inner corona. These estimates suggest that the solar wind has higher outflow speeds in the inner corona and lower densities than previously assumed. A comparison with densities derived from atmospheric models support these lower densities.

  7. Functionalized O6-Corona[6]arenes: Synthesis, Structure, and Fullerene Complexation Property.

    PubMed

    Ren, Wen-Sheng; Zhao, Liang; Wang, Mei-Xiang

    2016-07-01

    The synthesis, structure, and fullerene complexation property of novel and functionalized On-corona[n]arenes were reported. Based on the fragment coupling strategy, ester-containing On-corona[n]arenes (n = 6, 8) were obtained readily starting from 1,4-hydroquinone and diethyl 2,5-difluoroterephthalate. Reduction of esters with LiAlH4 produced almost quantitatively hydroxymethylated On-corona[n]arenes, which underwent etherification with MeI to afford methoxymethyl-substituted On-corona[n]arenes (n = 6, 8) in good yields. The macrocycles adopt unique corona-type conformation with a large cylindroid cavity. They are strong macrocyclic host molecules to form 1:1 complexes with fullerenes C60 and C70 in toluene with an associate constant up to (1.59 ± 0.04) × 10(5) M(-1).

  8. Nanoparticle corona for proteins: mechanisms of interaction between dendrimers and proteins.

    PubMed

    Shcharbin, Dzmitry; Ionov, Maksim; Abashkin, Viktar; Loznikova, Svetlana; Dzmitruk, Volha; Shcharbina, Natallia; Matusevich, Ludmila; Milowska, Katarzyna; Gałęcki, Krystian; Wysocki, Stanisław; Bryszewska, Maria

    2015-10-01

    Protein absorption at the surface of big nanoparticles and formation of 'protein corona' can completely change their biological properties. In contrast, we have studied the binding of small nanoparticles - dendrimers - to proteins and the formation of their 'nanoparticle corona'. Three different types of interactions were observed. (1) If proteins have rigid structure and active site buried deeply inside, the 'nanoparticle corona' is unaffected. (2) If proteins have a flexible structure and their active site is also buried deeply inside, the 'nanoparticle corona' affects protein structure, but not enzymatic activity. (3) The 'nanoparticle corona' changes both the structure and enzymatic activity of flexible proteins that have surface-based active centers. These differences are important in understanding interactions taking place at a bio-nanointerface.

  9. The "sweet" side of the protein corona: effects of glycosylation on nanoparticle-cell interactions.

    PubMed

    Wan, Sha; Kelly, Philip M; Mahon, Eugene; Stöckmann, Henning; Rudd, Pauline M; Caruso, Frank; Dawson, Kenneth A; Yan, Yan; Monopoli, Marco P

    2015-02-24

    The significance of a protein corona on nanoparticles in modulating particle properties and their biological interactions has been widely acknowledged. The protein corona is derived from proteins in biological fluids, many of which are glycosylated. To date, the glycans on the proteins have been largely overlooked in studies of nanoparticle-cell interactions. In this study, we demonstrate that glycosylation of the protein corona plays an important role in maintaining the colloidal stability of nanoparticles and influences nanoparticle-cell interactions. The removal of glycans from the protein corona enhances cell membrane adhesion and cell uptake of nanoparticles in comparison with the fully glycosylated form, resulting in the generation of a pro-inflammatory milieu by macrophages. This study highlights that the post-translational modification of proteins can significantly impact nanoparticle-cell interactions by modulating the protein corona properties.

  10. Understanding the nanoparticle-protein corona complexes using computational and experimental methods.

    PubMed

    Kharazian, B; Hadipour, N L; Ejtehadi, M R

    2016-06-01

    Nanoparticles (NP) have capability to adsorb proteins from biological fluids and form protein layer, which is called protein corona. As the cell sees corona coated NPs, the protein corona can dictate biological response to NPs. The composition of protein corona is varied by physicochemical properties of NPs including size, shape, surface chemistry. Processing of protein adsorption is dynamic phenomena; to that end, a protein may desorb or leave a surface vacancy that is rapidly filled by another protein and cause changes in the corona composition mainly by the Vroman effect. In this review, we discuss the interaction between NP and proteins and the available techniques for identification of NP-bound proteins. Also we review current developed computational methods for understanding the NP-protein complex interactions.

  11. Functionalized O6-Corona[6]arenes: Synthesis, Structure, and Fullerene Complexation Property.

    PubMed

    Ren, Wen-Sheng; Zhao, Liang; Wang, Mei-Xiang

    2016-07-01

    The synthesis, structure, and fullerene complexation property of novel and functionalized On-corona[n]arenes were reported. Based on the fragment coupling strategy, ester-containing On-corona[n]arenes (n = 6, 8) were obtained readily starting from 1,4-hydroquinone and diethyl 2,5-difluoroterephthalate. Reduction of esters with LiAlH4 produced almost quantitatively hydroxymethylated On-corona[n]arenes, which underwent etherification with MeI to afford methoxymethyl-substituted On-corona[n]arenes (n = 6, 8) in good yields. The macrocycles adopt unique corona-type conformation with a large cylindroid cavity. They are strong macrocyclic host molecules to form 1:1 complexes with fullerenes C60 and C70 in toluene with an associate constant up to (1.59 ± 0.04) × 10(5) M(-1). PMID:27324274

  12. Measurement of positive direct current corona pulse in coaxial wire-cylinder gap

    SciTech Connect

    Yin, Han Zhang, Bo He, Jinliang Wang, Wenzhuo

    2014-03-15

    In this paper, a system is designed and developed to measure the positive corona current in coaxial wire-cylinder gaps. The characteristic parameters of corona current pulses, such as the amplitude, rise time, half-wave time, and repetition frequency, are statistically analyzed and a new set of empirical formulas are derived by numerical fitting. The influence of space charges on corona currents is tested by using three corona cages with different radii. A numerical method is used to solve a simplified ion-flow model to explain the influence of space charges. Based on the statistical results, a stochastic model is developed to simulate the corona pulse trains. And this model is verified by comparing the simulated frequency-domain responses with the measured ones.

  13. A New Sheet Metal Forming System Based on Incremental Punching

    NASA Astrophysics Data System (ADS)

    Luo, Yuanxin

    Stamping is one of the most commonly used manufacturing processes. Everyday, millions of parts are formed by this process. The conventional stamping is to form a part in one or several operations with a press machine and a set/sets of dies. It is very efficient but is not cost effective for small batch production parts and prototypes as the dies are expensive and time consuming to make. Recently, with the increasing demands for low-volume and customer-made products, a die-less forming method, Incremental Sheet Metal Forming (ISMF), has become one of the leading R&D topics in the industry. ISMF uses a small generic tool to apply a sequence of operations along the given path to deform the sheet incrementally. These small deformations accumulate to form the final shape of the part. As a result, different parts can be made by the same setup. Despite of some 30 years of research and development, however, ISMF technology is still premature for industrial applications due to the following reasons: The accuracy of the part is limited; the surface roughness is poor; and the productivity is low. This motivates the presented research. In this research, a new incremental forming system based on incremental punching is designed and built. The system consists of a 3-axes CNC platform, a high speed hydraulic cylinder with a hemispherical forming tool, and a PC-based CNC control system. The hydraulic system provides the forming force to deform the sheet metal with constant stokes, while the CNC system positions the part. When forming a part, the forming tool punches the sheet metal along the given contour of the part punch by punch; when one layer of the part is completed, the forming tool moves down to the next layer; and the process is finished till all layers are completed. The CNC control system works with standard NC code, and hence, is easy to use. In order to ensure the desirable performance of the machine, dynamic analysis of the machine is necessary. The analysis is

  14. RXTE Observation of Cygnus X-1: III. Implications for Compton Corona and ADAF Models. Report 3; Implications for Compton Corona and ADAF Models

    NASA Technical Reports Server (NTRS)

    Nowak, Michael A.; Wilms, Joern; Vaughan, Brian A.; Dove, James B.; Begelman, Mitchell C.

    1999-01-01

    We have recently shown that a 'sphere + disk' geometry Compton corona model provides a good description of Rossi X-ray Timing Explorer (RXTE) observations of the hard/low state of Cygnus X-1. Separately, we have analyzed the temporal data provided by RXTE. In this paper we consider the implications of this timing analysis for our best-fit 'sphere + disk' Comptonization models. We focus our attention on the observed Fourier frequency-dependent time delays between hard and soft photons. We consider whether the observed time delays are: created in the disk but are merely reprocessed by the corona; created by differences between the hard and soft photon diffusion times in coronae with extremely large radii; or are due to 'propagation' of disturbances through the corona. We find that the time delays are most likely created directly within the corona; however, it is currently uncertain which specific model is the most likely explanation. Models that posit a large coronal radius [or equivalently, a large Advection Dominated Accretion Flow (ADAF) region] do not fully address all the details of the observed spectrum. The Compton corona models that do address the full spectrum do not contain dynamical information. We show, however, that simple phenomenological propagation models for the observed time delays for these latter models imply extremely slow characteristic propagation speeds within the coronal region.

  15. Real-time monitoring system for improving corona electrostatic separation in the process of recovering waste printed circuit boards.

    PubMed

    Li, Jia; Zhou, Quan; Xu, Zhenming

    2014-12-01

    Although corona electrostatic separation is successfully used in recycling waste printed circuit boards in industrial applications, there are problems that cannot be resolved completely, such as nonmetal particle aggregation and spark discharge. Both of these problems damage the process of separation and are not easy to identify during the process of separation in industrial applications. This paper provides a systematic study on a real-time monitoring system. Weight monitoring systems were established to continuously monitor the separation process. A Virtual Instrumentation program written by LabVIEW was utilized to sample and analyse the mass increment of the middling product. It includes four modules: historical data storage, steady-state analysis, data computing and alarm. Three kinds of operating conditions were used to verify the applicability of the monitoring system. It was found that the system achieved the goal of monitoring during the separation process and realized the function of real-time analysis of the received data. The system also gave comprehensible feedback on the accidents of material blockages in the feed inlet and high-voltage spark discharge. With the warning function of the alarm system, the whole monitoring system could save the human cost and help the new technology to be more easily applied in industry.

  16. Real-time monitoring system for improving corona electrostatic separation in the process of recovering waste printed circuit boards.

    PubMed

    Li, Jia; Zhou, Quan; Xu, Zhenming

    2014-12-01

    Although corona electrostatic separation is successfully used in recycling waste printed circuit boards in industrial applications, there are problems that cannot be resolved completely, such as nonmetal particle aggregation and spark discharge. Both of these problems damage the process of separation and are not easy to identify during the process of separation in industrial applications. This paper provides a systematic study on a real-time monitoring system. Weight monitoring systems were established to continuously monitor the separation process. A Virtual Instrumentation program written by LabVIEW was utilized to sample and analyse the mass increment of the middling product. It includes four modules: historical data storage, steady-state analysis, data computing and alarm. Three kinds of operating conditions were used to verify the applicability of the monitoring system. It was found that the system achieved the goal of monitoring during the separation process and realized the function of real-time analysis of the received data. The system also gave comprehensible feedback on the accidents of material blockages in the feed inlet and high-voltage spark discharge. With the warning function of the alarm system, the whole monitoring system could save the human cost and help the new technology to be more easily applied in industry. PMID:25395159

  17. Magnetic tornadoes as energy channels into the solar corona.

    PubMed

    Wedemeyer-Böhm, Sven; Scullion, Eamon; Steiner, Oskar; van der Voort, Luc Rouppe; de la Cruz Rodriguez, Jaime; Fedun, Viktor; Erdélyi, Robert

    2012-06-28

    Heating the outer layers of the magnetically quiet solar atmosphere to more than one million kelvin and accelerating the solar wind requires an energy flux of approximately 100 to 300 watts per square metre, but how this energy is transferred and dissipated there is a puzzle and several alternative solutions have been proposed. Braiding and twisting of magnetic field structures, which is caused by the convective flows at the solar surface, was suggested as an efficient mechanism for atmospheric heating. Convectively driven vortex flows that harbour magnetic fields are observed to be abundant in the photosphere (the visible surface of the Sun). Recently, corresponding swirling motions have been discovered in the chromosphere, the atmospheric layer sandwiched between the photosphere and the corona. Here we report the imprints of these chromospheric swirls in the transition region and low corona, and identify them as observational signatures of rapidly rotating magnetic structures. These ubiquitous structures, which resemble super-tornadoes under solar conditions, reach from the convection zone into the upper solar atmosphere and provide an alternative mechanism for channelling energy from the lower into the upper solar atmosphere. PMID:22739314

  18. Driving disk winds and heating hot coronae by MRI turbulence

    SciTech Connect

    Io, Yuki; Suzuki, Takeru K.

    2014-01-01

    We investigate the formation of hot coronae and vertical outflows in accretion disks by magnetorotational turbulence. We perform local three-dimensional magnetohydrodynamical (MHD) simulations with the vertical stratification by explicitly solving an energy equation with various effective ratios of specific heats, γ. Initially imposed weak vertical magnetic fields are effectively amplified by magnetorotational instability and winding caused by the differential rotation. In the isothermal case (γ = 1), the disk winds are driven mainly by the Poynting flux associated with the MHD turbulence and show quasi-periodic intermittency. In contrast, in the non-isothermal cases with γ ≥ 1.1, the regions above 1-2 scale heights from the midplane are effectively heated to form coronae with temperature ∼50 times the initial value, which are connected to the cooler midplane region through the pressure-balanced transition regions. As a result, the disk winds are driven mainly by the gas pressure, exhibiting more time-steady nature, although the nondimensional time-averaged mass loss rates are similar to that of the isothermal case. Sound-like waves are confined in the cool midplane region in these cases, and the amplitude of the density fluctuations is larger than that of the isothermal case.

  19. Milli-Arcsecond (MAS) Imaging of the Solar Corona

    NASA Astrophysics Data System (ADS)

    Davila, Joseph M.; Oktem, Figen S.; Kamalabadi, Farzad; O'Neill, John; Novo-Gradac, Anne-Marie; Daw, Adrian N.; Rabin, Douglas M.

    2016-05-01

    Dissipation in the solar corona is believed to occur in extremely thin current sheets of order 1-100 km. Emission from these hot but thin current sheets should be visible in coronal EUV emission lines. However, this spatial scale is far below the resolution of existing imaging instruments, so these dissipation sites have never been observed individually. Conventional optics cannot be manufactured with sufficient surface figure accuracy to obtain the required spatial resolution in the extreme-ultraviolet where these hot plasmas radiate. A photon sieve, a diffractive imaging element similar to a Fresnel zone plate, can be manufactured to provide a few milli-arcsec (MAS) resolution, with much more readily achievable tolerances than with conventional imaging technology. Prototype photon sieve elements have been fabricated and tested in the laboratory. A full-scale ultra-high resolution instrument will require formation flying and computational image deconvolution. Significant progress has been made in overcoming these challenges, and some recent results in these areas are discussed. A simple design for a sounding rocket concept demonstration payload is presented that obtains 80 MAS (0.080 arcsec) imaging with a 100 mm diameter photon sieve to image Fe XIV 334 and Fe XVI 335. These images will show the structure of the corona at a resolution never before obtained, and they will also allow a study of the temperature structure in the dissipation region.

  20. An XMM-Newton Study of σ 2 Coronae Borealis

    NASA Astrophysics Data System (ADS)

    Suh, J. A.; Audard, M.; Güdel, M.

    2003-12-01

    We present results of XMM-Newton Guaranteed Time observations of the RS CVn binary σ2 Coronae Borealis (F9 V + G0 V). The spectra obtained with the Reflection Grating Spectrometers and the European Photon Imaging Cameras were simultaneously fitted with collisional ionization equilibrium plasma models to determine coronal abundances of various elements. Contrary to the solar FIP effect in which elements with a low first ionization potential (FIP) are overabundant in the corona compared to the solar photosphere, and contrary to the "inverse" FIP effect observed in several active RS CVn binaries, coronal abundances in σ2 CrB do not show a significant pattern related to the FIP. This is supported by similar findings in the Chandra HETGS analysis of σ2 CrB with a different methodology (Osten et al. 2003). We also report low densities (< 4 × 1010 cm-3) from line ratios in the OVII He-like triplet. The Columbia group was supported by a grant from NASA to Columbia University for XMM-Newton mission support and data analysis.

  1. Milli-Arcsecond Imaging of the Solar Corona

    NASA Astrophysics Data System (ADS)

    Davila, Joseph; Kamalabadi, Farzad; Oktem, Figen S.

    2016-07-01

    Dissipation in the solar corona is believed to occur in extremely thin current sheets of order 1-100 km. Emission from these hot but thin current sheets is visible in coronal EUV emission lines, however, this spatial scale is unresolved in existing imaging instruments. Conventional optics cannot be easily manufactured with sufficient surface figure accuracy to obtain the required resolution. A photon sieve, a diffractive imaging element similar to a Fresnel zone plate, can be manufactured to provide a few milli-arcsec (mas) resolution, with much more relaxed tolerances than conventional imaging technology. Images from photon sieves will not only show the structure of the corona at a resolution never before obtained, they will also allow a study of the temperature structure in the dissipation region. Several photon sieves have been designed, fabricated, and tested by us at Goddard Space Flight Center. To fully exploit the potential of these devices two new technologies, (1) formation flying and (2) computational image deconvolution must be used. Recent progress on photon sieve development as well as these issues will be discussed. A simple design for a sounding rocket payload is presented that obtains 80 mas (0.080 arcsec) imaging with a 100 mm diameter photon sieve to image Fe XIV 334 and Fe XVI 335 which would provide a demonstration of this technology.

  2. The Solar Corona at the 2015 Total Solar Eclipse

    NASA Astrophysics Data System (ADS)

    Pasachoff, Jay M.; Carter, Allison L.

    2015-04-01

    We report on our successful observations of the solar corona at the 20 March 2015 total solar eclipse from our site at a latitude of about 78° on the Svalbard archipelago, and related observations by colleagues aloft. Our equipment included cameras for imaging at a variety of scales for use in making high-contrast composites, as reported our Astrophysical Journal article (2015) about our 2012 total solar eclipse observations and similar articles about the corona and changes in it at previous total eclipses. Our Svalbard equipment also included a spectrograph, with which we continued our monitoring of the ratio of the Fe XIV and Fe X coronal lines, which has recently been >1 with the solar maximum, a reversal from <1 at earlier eclipses closer to the last solar minimum. Our 2013 observations from Gabon showed two coronal mass ejections and an erupting prominence; the 2015 eclipse showed an erupting prominence and some unusual coronal structure in an overall coronal shape typical of solar maximum. We use our ground-based eclipse observations to fill the gap in imaging between the SDO and SWAP (17.4 nm) EUV observations on the solar disk and the inner location of the LASCO C2 occultation disk, with STEREO observations providing the possibility of three-dimensional interpretations. Our expedition was supported by a grant (9616-14) from the Committee for Research and Exploration of the National Geographic Society.

  3. Nitrogen fixation by corona discharge on the early precambrian Earth.

    PubMed

    Nna-Mvondo, Delphine; Navarro-González, Rafael; Raulin, François; Coll, Patrice

    2005-10-01

    We report the first experimental study of nitrogen fixation by corona discharge on the anoxic primitive Earth. The energy yields of nitric oxide (NO) and nitrous oxide (N(2)O) were experimentally determined over a wide range of CO(2)-N(2) mixtures simulating the evolution of the Earth's atmosphere during the Hadean and Archean eras (from 4.5 ba to 2.5 ba). NO, the principal form of fixed nitrogen in lightning and coronal discharge in early Earth, is produced ten times less efficiently in the latter type of electrical discharge with an estimated maximum annual production rate of the order of 10(10) g yr(-1). For N(2)O the maximum production rate was estimated to be approximately 10(9) g yr(-1). These low rates of syntheses indicate that corona discharges as point discharges on the clouds and ground did not play a significant role in the overall pool of reactive nitrogen needed for the emergence and sustainability of life.

  4. Chemical Compositions and Abundance Anomalies in Stellar Coronae ADP 99

    NASA Technical Reports Server (NTRS)

    Oliversen, Ronald J. (Technical Monitor); Drake, Jeremy

    2004-01-01

    New atomic data for tackling some of our spectra have been investigated by co-I Laming (NRL), including the effects of recombination on spectral line fluxes that are not included in, for example, the CHIANTI database models. Promising new progress has been made with modelling some of the recent abundance anomaly results in terms of Alven wave-driven separation of neutrals and ions in the upper chromosphere. The problems that existing models have is that they cannot simultaneously explain the low-FIP enhanced solar-like coronae and the high-FIP rich active coronae of RS CVn-like stars. The Alven wave model shows promise with both of these scenarios, with the fractionation or suppression of low-FIP ions depending on the characteristics of the chromosphere. This work is currently in the writing up stage. In summary, the work to-date is making good progress in mapping abundance anomalies as a function of spectral type and activity level. We are also making good progress with modelling that we will be able to test with our observational results. With one more year of effort, we'anticipate that the bulk of the work described above can be published, together with outstanding key studies on anomalies among the different active binaries.

  5. The EUV Emission in Comet-Solar Corona Interactions

    NASA Technical Reports Server (NTRS)

    Bryans, Paul; Pesnell, William Dean; Schrijver, Carolus J.; Brown, John C.; Battams, Karl; Saint-Hilaire, Pasal; Liu, Wei; Hudson, Hugh S.

    2011-01-01

    The Atmospheric Imaging Assembly (AlA) on the Solar Dynamics Observatory (SDO) viewed a comet as it passed through the solar corona on 2011 July 5. This was the first sighting of a comet by a EUV telescope. For 20 minutes, enhanced emission in several of the AlA wavelength bands marked the path of the comet. We explain this EUV emission by considering the evolution of the cometary atmosphere as it interacts with the ambient solar atmosphere. Water ice in the comet rapidly sublimates as it approaches the Sun. This water vapor is then photodissociated, primarily by Ly-alpha, by the solar radiation field to create atomic Hand O. Other molecules present in the comet also evaporate and dissociate to give atomic Fe and other metals. Subsequent ionization of these atoms can be achieved by a number of means, including photoionization, electron impact, and charge exchange with coronal protons and other highly-charged species. Finally, particles from the cometary atmosphere are thermalized to the background temperature of the corona. Each step could cause emission in the AlA bandpasses. We will report here on their relative contribution to the emission seen in the AlA telescopes.

  6. Spicules, mass transfer, oscillations, and the heating of the corona

    NASA Astrophysics Data System (ADS)

    Pasachoff, J. M.; Kozarev, K. A.; Butts, D. L.; Gangestad, J. W.; Seaton, D. B.; de Pontieu, B.; Golub, L.; Deluca, E.; Wilhelm, K.; Dammasch, I.

    2005-05-01

    The mass moving in chromospheric spicules is enough to replace the corona in a brief time, so understanding the dynamics of spicules is important for understanding the support and heating of the solar corona. We have undertaken a program involving simultaneous high-resolution observations in various chromospheric visible lines (H-alpha, Ca II H, and G-band, as well as Dopplergrams) using the Swedish Solar Telescope on La Palma, ultraviolet chromospheric, transition-region, and coronal lines (Fe IX/X 171 A, Lyman-alpha 1216 A, and continuum/C I/C IV 1600 A) using NASA's TRACE, and ultraviolet chromospheric and transition-region lines (Si II 1533, C IV 1548, and Ne VIII 770) using SUMER on SOHO. Our first coordinated observing run, in May 2004, yielded a variety of images that are under study, especially for the morphological statistics and dynamics of spicules. The energy transfer through the chromosphere is relevant to the overlapping investigation of coronal heating through rapid (1Hz range) oscillations of coronal loops as observed at total eclipses by Williams College expeditions. This research is supported by NASA grant number NNG04GK44G to Williams College. TRACE analysis at SAO is supported by a contract from Lockheed Martin. SOHO is a project of international cooperation between ESA and NASA.

  7. Magnetic tornadoes as energy channels into the solar corona.

    PubMed

    Wedemeyer-Böhm, Sven; Scullion, Eamon; Steiner, Oskar; van der Voort, Luc Rouppe; de la Cruz Rodriguez, Jaime; Fedun, Viktor; Erdélyi, Robert

    2012-06-27

    Heating the outer layers of the magnetically quiet solar atmosphere to more than one million kelvin and accelerating the solar wind requires an energy flux of approximately 100 to 300 watts per square metre, but how this energy is transferred and dissipated there is a puzzle and several alternative solutions have been proposed. Braiding and twisting of magnetic field structures, which is caused by the convective flows at the solar surface, was suggested as an efficient mechanism for atmospheric heating. Convectively driven vortex flows that harbour magnetic fields are observed to be abundant in the photosphere (the visible surface of the Sun). Recently, corresponding swirling motions have been discovered in the chromosphere, the atmospheric layer sandwiched between the photosphere and the corona. Here we report the imprints of these chromospheric swirls in the transition region and low corona, and identify them as observational signatures of rapidly rotating magnetic structures. These ubiquitous structures, which resemble super-tornadoes under solar conditions, reach from the convection zone into the upper solar atmosphere and provide an alternative mechanism for channelling energy from the lower into the upper solar atmosphere.

  8. The corona of V390 Aurigae (HD 33798)

    NASA Astrophysics Data System (ADS)

    Gondoin, P.

    2003-06-01

    V390 Aurigae (HD 33798) is a rapidly rotating, lithium rich, late-type giant whose distinctive characteristics include a high X-ray luminosity observed by the XMM-Newton space observatory. Series of lines of highly ionized Fe and several Lyman lines of hydrogen-like ions and triplet lines of helium-like ions are visible in the reflection grating spectra, most notably from O and Ne. X-ray emission from plasma at high temperature (T> 107 K) indicates intense flaring activity on this star. Analysis results suggest a scenario where the corona of V390 Aurigae is dominated by large magnetic structures similar in size to interconnecting loops between solar active regions but significantly hotter. The interaction of these structures could explain the permanent flaring activity on large scales that is responsible for heating plasma to high temperatures. The intense activity on V390 Aurigae is related to its evolutionary position at the bottom of the red giant branch. It is anticipated that the rotation of the star will spin-down in the future, thus decreasing the efficiency of its alpha -Omega dynamo with the suppressing of large scale magnetic structures in its corona.

  9. On the Deflection of CMEs in the Corona

    NASA Astrophysics Data System (ADS)

    Pomoell, J.; Vainio, R. O.; Kilpua, E.

    2009-12-01

    SOHO observations have revealed unambiguously that coronal mass ejections (CMEs) often do not propagate radially outwards with respect to the position of their source regions. It is commonly believed that coronal holes (CHs) play a significant role in the deflection of CMEs. For instance, it has been shown that the presence of CHs near the eruption region of a CME can explain why some interplanetary shocks arrive at Earth without a discernible ejecta behind them. Further, it has recently been proposed that the relative contribution of deflecting CMEs to the near-ecliptic ICME rate could be significant at solar minimum conditions. Despite these important implications, the deflection of CMEs itself has not received much attention. In this work, we study the deflection of CMEs in the low corona by simulations and observations. We focus especially on what role the magnetic environment of the source region as well as the size of the erupting structure has on deciding wether the CME experiences a deflection or not. Finally, we compare our simulation results to high-cadence quadrature STEREO observations of CME deflection in the low corona.

  10. Differential rotation, flares and coronae in A to M stars

    NASA Astrophysics Data System (ADS)

    Balona, L. A.; Švanda, M.; Karlický, M.

    2016-08-01

    Kepler data are used to investigate flares in stars of all spectral types. There is a strong tendency across all spectral types for the most energetic flares to occur among the most rapidly rotating stars. Differential rotation could conceivably play an important role in enhancing flare energies. This idea was investigated, but no correlation could be found between rotational shear and the incidence of flares. Inspection of Kepler light curves shows that rotational modulation is very common over the whole spectral type range. Using the rotational light amplitude, the size distribution of starspots was investigated. Our analysis suggests that stars with detectable flares have spots significantly larger than non-flare stars, indicating that flare energies are correlated with the size of the active region. Further evidence of the existence of spots on A stars is shown by the correlation between the photometric period and the projected rotational velocity. The existence of spots indicates the presence of magnetic fields, but the fact that A stars lack coronae implies that surface convection is a necessary condition for the formation of the corona.

  11. A Corona Discharge Initiated Electrochemical Electrospray Ionization Technique

    PubMed Central

    Lloyd, John R.; Hess, Sonja

    2009-01-01

    We report here the development of a corona discharge (CD) initiated electrochemical (EC) electrospray ionization (ESI) technique using a standard electrospray ion source. This is a new ionization technique distinct from ESI, electrochemistry inherent to ESI, APCI, and techniques using hydroxyl radicals produced under atmospheric pressure conditions. By maximizing the observable CD at the tip of a stainless steel ESI capillary, efficient electrochemical oxidation of electrochemically active compounds is observed. For electrochemical oxidation to be observed, the ionization potential of the analyte must be lower than Fe. Ferrocene labeled compounds were chosen as the electrochemically active moiety. The electrochemical cell in the ESI source was robust and generated ions with selectivity according to the ionization potential of the analytes and up to zeptomolar sensitivity. Our results indicate that CD initiated electrochemical ionization has the potential to become a powerful technique to increase the dynamic range, sensitivity and selectivity of ESI experiments. Synopsis Using a standard ESI source a corona discharge initiated electrochemical ionization technique was established resulting from the electrochemistry occurring at the CD electrode surface. PMID:19747843

  12. Confirmed Assignments of Isomeric Dimethylbenzyl Radicals Generated by Corona Discharge

    NASA Astrophysics Data System (ADS)

    Yoon, Young Wook; Lee, Sang Kuk

    2012-06-01

    Polymethylbenzyl radicals, multi-methyl-substituted benzyl radicals, have been believed to be an ideal model for understanding the torsional effect of methyl group and substitution effect on electronic transition. These radicals are mainly generated from polymethylbenzenes by electric discharge for spectroscopic observation. However, the existence of several methyl groups on the benzene ring may produce several isomeric polymethylbenzyl radicals by removing one of the C-H bonds of each methyl group at different substitution position, which makes the assignment of spectrum ambiguous. In this work, the controversial vibronic assignments of isomeric dimethylbenzyl radicals were clearly resolved by using different precursors. By using corresponding dimethylbenzyl chlorides as precursors, we identified the origins of the vibronic bands of the dimethylbenzyl radicals generated by corona discharge of precursors 1,2,3- and 1,2,4-trimethylbenzenes. From the analysis of the spectra observed from the dimethylbenzyl chlorides in a corona excited supersonic expansion using a pinhole-type glass nozzle, we revised previous assignments of the 2,6- and 2,3-dimethylbenzyl radicals as well as the 3,4-, 2,4-, and 2,5-dimethylbenzyl radicals. In addition, spectroscopic data of electronic transition and vibrational mode frequencies in the ground electronic state of each isomer were accurately determined by comparing them with those obtained by an ab initio calculation and with the known vibrational data of precursors.

  13. The global distribution of magnetic helicity in the solar corona

    NASA Astrophysics Data System (ADS)

    Yeates, A. R.; Hornig, G.

    2016-10-01

    By defining an appropriate field line helicity, we apply the powerful concept of magnetic helicity to the problem of global magnetic field evolution in the Sun's corona. As an ideal-magnetohydrodynamic invariant, the field line helicity is a meaningful measure of how magnetic helicity is distributed within the coronal volume. It may be interpreted, for each magnetic field line, as a magnetic flux linking with that field line. Using magneto-frictional simulations, we investigate how field line helicity evolves in the non-potential corona as a result of shearing by large-scale motions on the solar surface. On open magnetic field lines, the helicity injected by the Sun is largely output to the solar wind, provided that the coronal relaxation is sufficiently fast. But on closed magnetic field lines, helicity is able to build up. We find that the field line helicity is non-uniformly distributed, and is highly concentrated in twisted magnetic flux ropes. Eruption of these flux ropes is shown to lead to sudden bursts of helicity output, in contrast to the steady flux along the open magnetic field lines. Movies are available at http://www.aanda.org

  14. PLASMA DYNAMICS AT THE PROMINENCE-CORONA INTERFACE

    SciTech Connect

    Miloch, W. J.; Esser, R.; Habbal, S. R.

    2012-06-20

    The interface between the cool and dense plasma typical of a prominence and its tenuous and hot surrounding coronal plasma is poorly understood. We study the plasma dynamics at this interface using a three-dimensional particle-in-cell code, which enables us to carry out simulations on spatial and temporal scales of the order of the Debye length and plasma period, respectively. The results show that anomalous Bohm diffusion across magnetic field lines occurs at the interface, leading to mixing of the two plasmas. It is also shown that collisions with neutral hydrogen within the prominence plasma are of little importance for the plasma dynamics in the prominence-corona transition region. In particular, the temperature of the prominence plasma crossing the interface into the corona can become anisotropic due to preferential heating by instabilities originating from unstable velocity distributions. Our results pertain to spatial scales significantly smaller than scales commonly used in magnetohydrodynamic simulations, and they shed light on processes that are very likely to be present at the interface.

  15. Corongraphic Observations and Analyses of The Ultraviolet Solar Corona

    NASA Technical Reports Server (NTRS)

    Kohl, John L.

    2000-01-01

    The activities supported under NASA Grant NAG5-613 included the following: 1) reduction and scientific analysis of data from three sounding rocket flights of the Rocket Ultraviolet Coronagraph Spectrometer, 2) development of ultraviolet spectroscopic diagnostic techniques to provide a detailed empirical description of the extended solar corona, 3) extensive upgrade of the rocket instrument to become the Ultraviolet Coronal Spectrometer (UVCS) for Spartan 201,4) instrument scientific calibration and characterization, 5) observation planning and mission support for a series of five Spartan 201 missions (fully successful except for STS 87 where the Spartan spacecraft was not successfully deployed and the instruments were not activated), and 6) reduction and scientific analysis of the UVCS/Spartan 201 observational data. The Ultraviolet Coronal Spectrometer for Spartan 201 was one unit of a joint payload and the other unit was a White Light Coronagraph (WLC) provided by the High Altitude Observatory and the Goddard Space Flight Center. The two instruments were used in concert to determine plasma parameters describing structures in the extended solar corona. They provided data that could be used individually or jointly in scientific analyses. The WLC provided electron column densities in high spatial resolution and high time resolution. UVCS/Spartan provided hydrogen velocity distributions, and line of sight hydrogen velocities. The hydrogen intensities from UVCS together with the electron densities from WLC were used to determine hydrogen outflow velocities. The UVCS also provided O VI intensities which were used to develop diagnostics for velocity distributions and outflow velocities of minor ions.

  16. Indian Solar mission to study inner solar corona: Aditya 1

    NASA Astrophysics Data System (ADS)

    Singh, Jagdev; Banerjee, Dipankar; Venkatakrishnan, Parameswaran; Kasiviswanathan, Sankarasubramanian; Prasad B, Raghavendra

    2012-07-01

    Aditya-I is India's first dedicated scientific mission to study the sun. This is a low-earth orbit (LEO) mission at an altitude of 800 km. A visible emission line space solar coronagraph (VELC) has been selected as a payload under the small-satellite program of ISRO. It will provide high time cadence sharp images of the solar corona in the Green and Red Emission lines. These images will be used to study the highly dynamic nature of the solar corona including the small-scale coronal loops and large-scale Coronal Mass Ejections (CMEs). The uniqueness of this payload compared to previously flown space instruments are: (a) Observations in the visible wavelength closer to the disk (down to 1.05 solar radii), (b) high time cadence capability (better than 2-images per second), and (c) Simultaneous observations of at least two spectral windows all the time and three spectral windows for short durations. I will update the current status of the project and will point out the complimentary role Aditya can play in conjunction with other solar big missions like SDO.

  17. Spatial and temporal relations between coronae and extensional belts, northern Lada Terra, Venus

    NASA Technical Reports Server (NTRS)

    Baer, Gidon; Schubert, Gerald; Bindschadler, Duane L.; Stofan, Ellen R.

    1994-01-01

    Preliminary studies of the distribution of coronae and volcanic rises on Venus show that many of these features tend to cluster along zones of rifting and extension. The plains north of Lada Terra are crossed by two such extensional belts. Each belt is composed of grabens, ridges, faults, volcanic flows, coronae and coronalike features. The longer and more prominent belt is the NW trending Alpha-Lada extensional belt, which is over 6000 km long and 50-200 km wide, and includes the coronae Eve, Tamfana, Carpo, Selu, Derceto, Otygen, and an unnamed corona south of Otygen. The second belt is the NNE trending Derceto-Quetzalpetlatl extensional belt, which is about 2000 km long and in places over 300 km wide, and includes the coronae Sarpanitum, Eithinoha, and Quetzalpetlatl. The two belts intersect at the 1600 x 600 km wide Derceto volcanic plateau. It is apparent that deformation along the two belts overlapped in time, though deformation along the Alpha-Lada extensional belt probably continued after the deformation along the Derceto-Quetzalpetlatl extensional belt terminated. In certain areas, volcanism originated in grabens within the extensional belts, whereas in other areas, such as in Eve, Selu, Derceto, and Quetzalpetlatl, volcanism originated in the coronae and flowed into the lower parts of the extensional belts. Regional extension has affected the evolution of all the coronae at some stage of their development. Regional deformation occurred before the initiation of Derceto and Eithinoha of their development. Regional deformation occurred before the initiation of Derceto and Eithinoha and after the initiation of Carpo, Tamfana, Otygen, and Sarpanitum. It is thus unlikely that coronae formation along the belts is solely a consequence of the regional extension, and it is also unlikely that regional extension has been caused solely by the coronae. No corona along the belts was formed subsequent to the cessation of the regional extension. We therefore suggest that

  18. Spatial and temporal relations between coronae and extensional belts, northern Lada Terra, Venus

    NASA Astrophysics Data System (ADS)

    Baer, G.; Schubert, G.; Bindschadler, D. L.; Stofan, E. R.

    1994-04-01

    Preliminary studies of the distribution of coronae and volcanic rises on Venus show that many of these features tend to cluster along zones of rifting and extension. The plains north of Lada Terra are crossed by two such extensional belts. Each belt is composed of grabens, ridges, faults, volcanic flows, coronae and coronalike features. The longer and more prominent belt is the NW trending Alpha-Lada extensional belt, which is over 6000 km long and 50-200 km wide, and includes the coronae Eve, Tamfana, Carpo, Selu, Derceto, Otygen, and an unnamed corona south of Otygen. The second belt is the NNE trending Derceto-Quetzalpetlatl extensional belt, which is about 2000 km long and in places over 300 km wide, and includes the coronae Sarpanitum, Eithinoha, and Quetzalpetlatl. The two belts intersect at the 1600 x 600 km wide Derceto volcanic plateau. It is apparent that deformation along the two belts overlapped in time, though deformation along the Alpha-Lada extensional belt probably continued after the deformation along the Derceto-Quetzalpetlatl extensional belt terminated. In certain areas, volcanism originated in grabens within the extensional belts, whereas in other areas, such as in Eve, Selu, Derceto, and Quetzalpetlatl, volcanism originated in the coronae and flowed into the lower parts of the extensional belts. Regional extension has affected the evolution of all the coronae at some stage of their development. Regional deformation occurred before the initiation of Derceto and Eithinoha of their development. Regional deformation occurred before the initiation of Derceto and Eithinoha and after the initiation of Carpo, Tamfana, Otygen, and Sarpanitum. It is thus unlikely that coronae formation along the belts is solely a consequence of the regional extension, and it is also unlikely that regional extension has been caused solely by the coronae. No corona along the belts was formed subsequent to the cessation of the regional extension. We therefore suggest that

  19. The effects of prior incremental cycle exercise on the physiological responses during incremental running to exhaustion: relevance for sprint triathlon performance.

    PubMed

    Bentley, David J; McNaughton, Lars R; Lamyman, Robert; Roberts, Simon P

    2003-01-01

    It is common for the physiological working capacity of a triathlete when cycling and running to be assessed on two separate days. The aim of this study was to establish whether an incremental running test to exhaustion has a negative effect after a 5 h recovery from an incremental cycling test. Eight moderately trained triathletes (age, 26.2 +/- 3.4 years; body mass, 67.3 +/- 9.1 kg; VO2max when cycling, 59 +/- 13 ml x kg x min(-1); mean +/- s) completed an incremental running test 5 h after an incremental cycling test (fatigue) as well as an incremental running test without previous activity (control). Maximum running speed, maximal oxygen uptake (VO2max) and the lactate threshold were determined for each incremental running test and correlated with the average speed during a 5 km run, which was performed immediately after a 20 km cycling time-trial, as in a sprint triathlon. There were no significant differences in maximum running speed, VO2max or the lactate threshold in either incremental running test (control or fatigue). Furthermore, good agreement was found for each physiological variable in both the control and fatigue tests. For the fatigue test, there were significant correlations between the average speed during a 5 km run and both VO2max expressed in absolute terms (r = 0.83) and the lactate threshold (r = 0.88). However, maximum running speed correlated most strongly with the average speed during a 5 km run (r = 0.96). The results of this study indicate that, under controlled conditions, an incremental running test can be performed successfully 5 h after an incremental cycling test to exhaustion. Also, the maximum running speed achieved during an incremental running test is the variable that correlates most strongly with the average running speed during a 5 km run after a 20 km cycling time-trial in well-trained triathletes. PMID:12587889

  20. A New Method for Incremental Testing of Finite State Machines

    NASA Technical Reports Server (NTRS)

    Pedrosa, Lehilton Lelis Chaves; Moura, Arnaldo Vieira

    2010-01-01

    The automatic generation of test cases is an important issue for conformance testing of several critical systems. We present a new method for the derivation of test suites when the specification is modeled as a combined Finite State Machine (FSM). A combined FSM is obtained conjoining previously tested submachines with newly added states. This new concept is used to describe a fault model suitable for incremental testing of new systems, or for retesting modified implementations. For this fault model, only the newly added or modified states need to be tested, thereby considerably reducing the size of the test suites. The new method is a generalization of the well-known W-method and the G-method, but is scalable, and so it can be used to test FSMs with an arbitrarily large number of states.

  1. Low-Rank Incremental Methods for Computing Dominant Singular Subspaces

    SciTech Connect

    Baker, Christopher G; Gallivan, Dr. Kyle A; Van Dooren, Dr. Paul

    2012-01-01

    Computing the singular values and vectors of a matrix is a crucial kernel in numerous scientific and industrial applications. As such, numerous methods have been proposed to handle this problem in a computationally efficient way. This paper considers a family of methods for incrementally computing the dominant SVD of a large matrix A. Specifically, we describe a unification of a number of previously disparate methods for approximating the dominant SVD via a single pass through A. We tie the behavior of these methods to that of a class of optimization-based iterative eigensolvers on A'*A. An iterative procedure is proposed which allows the computation of an accurate dominant SVD via multiple passes through A. We present an analysis of the convergence of this iteration, and provide empirical demonstration of the proposed method on both synthetic and benchmark data.

  2. An Incremental Map Building Approach via Static Stixel Integration

    NASA Astrophysics Data System (ADS)

    Muffert, M.; Anzt, S.; Franke, U.

    2013-10-01

    This paper presents a stereo-vision based incremental mapping approach for urban regions. As input, we use the 3D representation called multi-layered Stixel World which is computed from dense disparity images. More and more, researchers of Driver Assistance Systems rely on efficient and compact 3D representations like the Stixel World. The developed mapping approach takes into account the motion state of obstacles, as well as free space information obtained from the Stixel World. The presented work is based on the well known occupancy grid mapping technique and is formulated with evidential theory. A detailed sensor model is described which is used to determine the information whether a grid cell is occupied, free or has an unknown state. The map update is solved in a time recursive manner by using the Dempster`s Rule of Combination. 3D results of complex inner city regions are shown and are compared with Google Earth images.

  3. [Design of an Incremental and Open Laboratory Automation System].

    PubMed

    Xie, Chuanfen; Chen, Yueping; Wang, Zhihong

    2015-07-01

    Recent years have witnessed great development of TLA (Total Laboratory Automation) technology, however, its application hit the bottleneck of high cost and openess to other parties' instruments. Specifically speaking, the initial purchase of the medical devices requires large sum of money and the new system can hardly be compatible with existing equipment. This thesis proposes a new thought for system implementation that through incremental upgrade, the initial capital investment can be reduced and through open architecture and interfaces, the seamless connection of different devices can be achieved. This thesis elaborates on the standards that open architecture design should follow in aspect of mechanics, electro-communication and information interaction and the key technology points in system implementation. PMID:26665947

  4. Quantifiers are incrementally interpreted in context, more than less

    PubMed Central

    Urbach, Thomas P.; DeLong, Katherine A.; Kutas, Marta

    2015-01-01

    Language interpretation is often assumed to be incremental. However, our studies of quantifier expressions in isolated sentences found N400 event-related brain potential (ERP) evidence for partial but not full immediate quantifier interpretation (Urbach & Kutas, 2010). Here we tested similar quantifier expressions in pragmatically supporting discourse contexts (Alex was an unusual toddler. Most/Few kids prefer sweets/vegetables…) while participants made plausibility judgments (Experiment 1) or read for comprehension (Experiment 2). Control Experiments 3A (plausibility) and 3B (comprehension) removed the discourse contexts. Quantifiers always modulated typical and/or atypical word N400 amplitudes. However, only the real-time N400 effects only in Experiment 2 mirrored offline quantifier and typicality crossover interaction effects for plausibility ratings and cloze probabilities. We conclude that quantifier expressions can be interpreted fully and immediately, though pragmatic and task variables appear to impact the speed and/or depth of quantifier interpretation. PMID:26005285

  5. An incremental design of radial basis function networks.

    PubMed

    Yu, Hao; Reiner, Philip D; Xie, Tiantian; Bartczak, Tomasz; Wilamowski, Bogdan M

    2014-10-01

    This paper proposes an offline algorithm for incrementally constructing and training radial basis function (RBF) networks. In each iteration of the error correction (ErrCor) algorithm, one RBF unit is added to fit and then eliminate the highest peak (or lowest valley) in the error surface. This process is repeated until a desired error level is reached. Experimental results on real world data sets show that the ErrCor algorithm designs very compact RBF networks compared with the other investigated algorithms. Several benchmark tests such as the duplicate patterns test and the two spiral problem were applied to show the robustness of the ErrCor algorithm. The proposed ErrCor algorithm generates very compact networks. This compactness leads to greatly reduced computation times of trained networks.

  6. Incremental cost pricing of transmission services. Final report

    SciTech Connect

    Not Available

    1994-12-01

    This report, prepared by ICF Resources, under a sub-contract with IT Corporation, is concerned chiefly with examining the economic concepts underlying an Incremental Cost Pricing Framework (ICPF), which is defined here as a pricing regime that takes into account several factors: economic efficiency in terms of sending the correct long-term price signals to both users and owners of transmission assets; pricing of individual services in relationship to cost causation; full recovery of costs associated with transmission service; and applicability to real-world power systems without extraordinary administrative burdens. In the course of this examination, the report makes assumptions, as necessary, and assesses the extent to which they may or may not comport with real-world conditions. It also assesses the pros and cons of different approaches to pricing various components of transmission service without making a recommendation as to the superiority of one approach over another from a public policy perspective.

  7. [Hormonal changes during incremental exercise in athletic women].

    PubMed

    Mesaki, N; Sasaki, J; Shoji, M; Iwasaki, H; Asano, K; Eda, M

    1986-01-01

    Recently, the number of women who participate in strenuous sports has increased rapidly. The evidence indicating a causal relationship between athletic activity and increased incidence of menstrual dysfunction has led to increased interest. Five basketball players who are among the top players in Japan were subjected to an investigation of the endocrinological responses effected by incremental exercise using a cycle ergometer. Serum levels of FSH and LH decreased significantly in the follicular phase, but there was no change in the luteal phase. Estradiol was seen to increase significantly in the luteal phase but no change occurred in the follicular phase. Progesterone did not show a significant change during exercise. Although TSH did not show any significant change, prolactin showed a significant increase in both phases. These results suggest that strenuous daily training leads to a frequent increase of prolactin in athletic women and this frequent increase of prolactin may be one of the major factors in causing menstrual dysfunction.

  8. Endorectal MRI of Prostate Cancer: Incremental Prognostic Importance of Gross Locally Advanced Disease

    PubMed Central

    Muglia, Valdair F.; Westphalen, Antonio C.; Wang, Zhen J.; Kurhanewicz, John; Carroll, Peter R.; Coakley, Fergus V.

    2013-01-01

    OBJECTIVE The purpose of this study was to determine the frequency and incremental prognostic importance of gross locally advanced disease seen at endorectal MRI in patients with prostate cancer. MATERIALS AND METHODS We retrospectively identified the cases of all patients with biopsy-proven prostate cancer who underwent pretreatment endorectal MRI over a 6-year period (n = 1777). Three experienced radiologists identified by consensus patients with gross locally advanced disease, defined as unequivocal extracapsular extension or unequivocal seminal vesicle invasion. Outcome among these patients was compared with that in a control group without gross locally advanced disease matched by D'Amico risk stratification. RESULTS Sixty-six of 1777 (3.7%) patients had gross locally advanced disease. One of 1085 (0.1%) patients had low-risk disease, 25 of 489 (5.1%) had intermediate-risk disease, and 40 of 203 (19.7%) had high-risk disease. Follow-up data were available for 44 of these 66 patients. During a median follow-up period of 79 months, biochemical failure and metastasis had developed in 17 and 6 of these 44 patients compared with 9 and none of the 65 patients in the control group (p < 0.001). CONCLUSION Almost 4% of patients with prostate cancer, particularly those with intermediate- and high-risk disease, have gross locally advanced disease at endorectal MRI and have a significantly worse prognosis than matched controls. These patients may be candidates for more aggressive treatment. PMID:22109291

  9. Degradation reliability modeling based on an independent increment process with quadratic variance

    NASA Astrophysics Data System (ADS)

    Wang, Zhihua; Zhang, Yongbo; Wu, Qiong; Fu, Huimin; Liu, Chengrui; Krishnaswamy, Sridhar

    2016-03-01

    Degradation testing is an important technique for assessing life time information of complex systems and highly reliable products. Motivated by fatigue crack growth (FCG) data and our previous study, this paper develops a novel degradation modeling approach, in which degradation is represented by an independent increment process with linear mean and general quadratic variance functions of test time or transformed test time if necessary. Based on the constructed degradation model, closed-form expressions of failure time distribution (FTD) and its percentiles can be straightforwardly derived and calculated. A one-stage method is developed to estimate model parameters and FTD. Simulation studies are conducted to validate the proposed approach, and the results illustrate that the approach can provide reasonable estimates even for small sample size situations. Finally, the method is verified by the FCG data set given as the motivating example, and the results show that it can be considered as an effective degradation modeling approach compared with the multivariate normal model and graphic approach.

  10. Pacing accuracy during an incremental step test in adolescent swimmers.

    PubMed

    Scruton, Adrian; Baker, James; Roberts, Justin; Basevitch, Itay; Merzbach, Viviane; Gordon, Dan

    2015-01-01

    To assess pacing accuracy in a group of adolescent swimmers during an incremental step test. Fifteen well-trained swimmers (age 15±1.5 years; height 170.2±8.8 cm; mass 60.2±6.6 kg), completed two 7×200 m tests, separated by ~72 hours. They swam to a predetermined incrementally increasing pace per step and were instructed to swim at even pace. Upon completion of each step, rating of perceived exertion, heart rate and blood lactate were recorded. Significant differences observed for both trials between actual and predicted swim time (P<0.05). Significant differences also observed between the first and second 100 m of each step in trial 1 for step 1 (P=0.001, effect size [ES] =0.54), step 2 (P=0.0001, ES =0.57), step 4 (P=0.0001, ES =0.53), step 5 (P=0.005, ES =0.65), step 6 (P=0.0001, ES =0.50), and step 7 (P=0.0001, ES =0.70). Similar responses witnessed for trial 2 (P<0.05). Findings suggest that the finite anaerobic capacity was engaged sooner than would normally be anticipated, as a function of an inability to regulate pace. This is proposed to be a consequence of the volume of exposure to the biological and psychological sensations and cognitive developmental status. Given the apparent error in pacing judgment exhibited in this population group, caution should be applied when adopting such tests to monitor training responses with adolescent athletes, and alternate means of modulating pace be investigated.

  11. Incremental enamel development in modern human deciduous anterior teeth.

    PubMed

    Mahoney, Patrick

    2012-04-01

    This study reconstructs incremental enamel development for a sample of modern human deciduous mandibular (n = 42) and maxillary (n = 42) anterior (incisors and canines) teeth. Results are compared between anterior teeth, and with previous research for deciduous molars (Mahoney: Am J Phys Anthropol 144 (2011) 204-214) to identify developmental differences along the tooth row. Two hypotheses are tested: Retzius line periodicity will remain constant in teeth from the same jaw and range from 6 to 12 days among individuals, as in human permanent teeth; daily enamel secretion rates (DSRs) will not vary between deciduous teeth, as in some human permanent tooth types. A further aim is to search for links between deciduous incremental enamel development and the previously reported eruptionsequence. Retzius line periodicity in anterior teeth ranged between 5 and 6 days, but did not differ between an incisor and molar of one individual. Intradian line periodicity was 12 h. Mean cuspal DSRs varied slightly between equivalent regions along the tooth row. Mandibular incisors initiated enamel formation first, had the fastest mean DSRs, the greatest prenatal formation time, and based upon prior studies are the first deciduous tooth to erupt. Relatively rapid development in mandibular incisors in advance of early eruption may explain some of the variation in DSRs along the tooth row that cannot be explained by birth. Links between DSRs, enamel initiation times, and the deciduous eruption sequence are proposed. Anterior crown formation times presented here can contribute toward human infant age-at-death estimates. Regression equations for reconstructing formation time in worn incisors are given.

  12. Pacing accuracy during an incremental step test in adolescent swimmers

    PubMed Central

    Scruton, Adrian; Baker, James; Roberts, Justin; Basevitch, Itay; Merzbach, Viviane; Gordon, Dan

    2015-01-01

    To assess pacing accuracy in a group of adolescent swimmers during an incremental step test. Fifteen well-trained swimmers (age 15±1.5 years; height 170.2±8.8 cm; mass 60.2±6.6 kg), completed two 7×200 m tests, separated by ~72 hours. They swam to a predetermined incrementally increasing pace per step and were instructed to swim at even pace. Upon completion of each step, rating of perceived exertion, heart rate and blood lactate were recorded. Significant differences observed for both trials between actual and predicted swim time (P<0.05). Significant differences also observed between the first and second 100 m of each step in trial 1 for step 1 (P=0.001, effect size [ES] =0.54), step 2 (P=0.0001, ES =0.57), step 4 (P=0.0001, ES =0.53), step 5 (P=0.005, ES =0.65), step 6 (P=0.0001, ES =0.50), and step 7 (P=0.0001, ES =0.70). Similar responses witnessed for trial 2 (P<0.05). Findings suggest that the finite anaerobic capacity was engaged sooner than would normally be anticipated, as a function of an inability to regulate pace. This is proposed to be a consequence of the volume of exposure to the biological and psychological sensations and cognitive developmental status. Given the apparent error in pacing judgment exhibited in this population group, caution should be applied when adopting such tests to monitor training responses with adolescent athletes, and alternate means of modulating pace be investigated. PMID:26346728

  13. Contraceptive failure in China.

    PubMed

    Wang, Duolao

    2002-09-01

    This study examines patterns and differentials of contraceptive failure rates by method and characteristics of users, using the Chinese Two-per-Thousand Fertility Survey data. The results show that contraceptive failure rates for modern methods including sterilization are some of the highest in the world. The first year failure rates are 4.2% for male sterilization, 0.7% for female sterilization, 10.3% for IUD, 14.5% for pill, and 19.0% for condom. There are also some differentials in contraceptive failure rates by users' sociodemographic and fertility characteristics. Contraceptive failure rate declines with women's age for all reversible methods. Rural women have higher sterilization, IUD, and condom contraceptive failure rates than urban women. Women with two or more children have a higher failure rate for sterilization methods but have lower failure rates for other methods.

  14. Predicting Cell Association of Surface-Modified Nanoparticles Using Protein Corona Structure - Activity Relationships (PCSAR).

    PubMed

    Kamath, Padmaja; Fernandez, Alberto; Giralt, Francesc; Rallo, Robert

    2015-01-01

    Nanoparticles are likely to interact in real-case application scenarios with mixtures of proteins and biomolecules that will absorb onto their surface forming the so-called protein corona. Information related to the composition of the protein corona and net cell association was collected from literature for a library of surface-modified gold and silver nanoparticles. For each protein in the corona, sequence information was extracted and used to calculate physicochemical properties and statistical descriptors. Data cleaning and preprocessing techniques including statistical analysis and feature selection methods were applied to remove highly correlated, redundant and non-significant features. A weighting technique was applied to construct specific signatures that represent the corona composition for each nanoparticle. Using this basic set of protein descriptors, a new Protein Corona Structure-Activity Relationship (PCSAR) that relates net cell association with the physicochemical descriptors of the proteins that form the corona was developed and validated. The features that resulted from the feature selection were in line with already published literature, and the computational model constructed on these features had a good accuracy (R(2)LOO=0.76 and R(2)LMO(25%)=0.72) and stability, with the advantage that the fingerprints based on physicochemical descriptors were independent of the specific proteins that form the corona.

  15. Protein corona composition does not accurately predict hematocompatibility of colloidal gold nanoparticles.

    PubMed

    Dobrovolskaia, Marina A; Neun, Barry W; Man, Sonny; Ye, Xiaoying; Hansen, Matthew; Patri, Anil K; Crist, Rachael M; McNeil, Scott E

    2014-10-01

    Proteins bound to nanoparticle surfaces are known to affect particle clearance by influencing immune cell uptake and distribution to the organs of the mononuclear phagocytic system. The composition of the protein corona has been described for several types of nanomaterials, but the role of the corona in nanoparticle biocompatibility is not well established. In this study we investigate the role of nanoparticle surface properties (PEGylation) and incubation times on the protein coronas of colloidal gold nanoparticles. While neither incubation time nor PEG molecular weight affected the specific proteins in the protein corona, the total amount of protein binding was governed by the molecular weight of PEG coating. Furthermore, the composition of the protein corona did not correlate with nanoparticle hematocompatibility. Specialized hematological tests should be used to deduce nanoparticle hematotoxicity. From the clinical editor: It is overall unclear how the protein corona associated with colloidal gold nanoparticles may influence hematotoxicity. This study warns that PEGylation itself may be insufficient, because composition of the protein corona does not directly correlate with nanoparticle hematocompatibility. The authors suggest that specialized hematological tests must be used to deduce nanoparticle hematotoxicity.

  16. Utilizing the protein corona around silica nanoparticles for dual drug loading and release.

    PubMed

    Shahabi, Shakiba; Treccani, Laura; Dringen, Ralf; Rezwan, Kurosch

    2015-10-21

    A protein corona forms spontaneously around silica nanoparticles (SNPs) in serum-containing media. To test whether this protein corona can be utilized for the loading and release of anticancer drugs we incorporated the hydrophilic doxorubicin, the hydrophobic meloxicam as well as their combination in the corona around SNPs. The application of corona-covered SNPs to osteosarcoma cells revealed that drug-free particles did not affect the cell viability. In contrast, SNPs carrying a protein corona with doxorubicin or meloxicam lowered the cell proliferation in a concentration-dependent manner. In addition, these particles had an even greater antiproliferative potential than the respective concentrations of free drugs. The best antiproliferative effects were observed for SNPs containing both doxorubicin and meloxicam in their corona. Co-localization studies revealed the presence of doxorubicin fluorescence in the nucleus and lysosomes of cells exposed to doxorubicin-containing coated SNPs, suggesting that endocytotic uptake of the SNPs facilitates the cellular accumulation of the drug. Our data demonstrate that the protein corona, which spontaneously forms around nanoparticles, can be efficiently exploited for loading the particles with multiple drugs for therapeutic purposes. As drugs are efficiently released from such particles they may have a great potential for nanomedical applications.

  17. Ex situ evaluation of the composition of protein corona of intravenously injected superparamagnetic nanoparticles in rats.

    PubMed

    Sakulkhu, Usawadee; Maurizi, Lionel; Mahmoudi, Morteza; Motazacker, Mahdi; Vries, Marcel; Gramoun, Azza; Ollivier Beuzelin, Marie-Gabrielle; Vallée, Jean-Paul; Rezaee, Farhad; Hofmann, Heinrich

    2014-10-01

    It is now well recognized that the surfaces of nanoparticles (NPs) are coated with biomolecules (e.g., proteins) in a biological medium. Although extensive reports have been published on the protein corona at the surface of NPs in vitro, there are very few on the in vivo protein corona. The main reason for having very poor information regarding the protein corona in vivo is that separation of NPs from the in vivo environment has not been possible by using available techniques. Knowledge of the in vivo protein corona could lead to better understanding and prediction of the fate of NPs in vivo. Here, by using the unique magnetic properties of superparamagnetic iron oxide NPs (SPIONs), NPs were extracted from rat sera after in vivo interaction with the rat's physiological system. More specifically, the in vivo protein coronas of polyvinyl-alcohol-coated SPIONs with various surface charges are defined. The compositions of the corona at the surface of various SPIONs and their effects on the biodistribution of SPIONs were examined and compared with the corona composition of particles incubated for the same time in rat serum.

  18. ZnO Nanowire-Based Corona Discharge Devices Operated Under Hundreds of Volts.

    PubMed

    Yang, Wenming; Zhu, Rong; Zong, Xianli

    2016-12-01

    Minimizing the voltage of corona discharges, especially when using nanomaterials, has been of great interest in the past decade or so. In this paper, we report a new corona discharge device by using ZnO nanowires operated in atmospheric air to realize continuous corona discharge excited by hundreds of volts. ZnO nanowires were synthesized on microelectrodes using electric-field-assisted wet chemical method, and a thin tungsten film was deposited on the microchip to enhance discharging performance. The testing results showed that the corona inception voltages were minimized greatly by using nanowires compared to conventional dischargers as a result of the local field enhancement of nanowires. The corona could be continuously generated and self-sustaining. It was proved that the law of corona inception voltage obeyed the conventional Peek's breakdown criterion. An optimal thickness of tungsten film coated over ZnO nanowires was figured out to obtain the lowest corona inception voltage. The ion concentration of the nanowire-based discharger attained 10(17)/m(3) orders of magnitude, which is practicable for most discharging applications.

  19. Personalized disease-specific protein corona influences the therapeutic impact of graphene oxide.

    PubMed

    Hajipour, Mohammad Javad; Raheb, Jamshid; Akhavan, Omid; Arjmand, Sareh; Mashinchian, Omid; Rahman, Masoud; Abdolahad, Mohammad; Serpooshan, Vahid; Laurent, Sophie; Mahmoudi, Morteza

    2015-05-21

    The hard corona, the protein shell that is strongly attached to the surface of nano-objects in biological fluids, is recognized as the first layer that interacts with biological objects (e.g., cells and tissues). The decoration of the hard corona (i.e., the type, amount, and conformation of the attached proteins) can define the biological fate of the nanomaterial. Recent developments have revealed that corona decoration strongly depends on the type of disease in human patients from which the plasma is obtained as a protein source for corona formation (referred to as the 'personalized protein corona'). In this study, we demonstrate that graphene oxide (GO) sheets can trigger different biological responses in the presence of coronas obtained from various types of diseases. GO sheets were incubated with plasma from human subjects with different diseases/conditions, including hypofibrinogenemia, blood cancer, thalassemia major, thalassemia minor, rheumatism, fauvism, hypercholesterolemia, diabetes, and pregnancy. Identical sheets coated with varying protein corona decorations exhibited significantly different cellular toxicity, apoptosis, and uptake, reactive oxygen species production, lipid peroxidation and nitrogen oxide levels. The results of this report will help researchers design efficient and safe, patient-specific nano biomaterials in a disease type-specific manner for clinical and biological applications.

  20. ZnO Nanowire-Based Corona Discharge Devices Operated Under Hundreds of Volts.

    PubMed

    Yang, Wenming; Zhu, Rong; Zong, Xianli

    2016-12-01

    Minimizing the voltage of corona discharges, especially when using nanomaterials, has been of great interest in the past decade or so. In this paper, we report a new corona discharge device by using ZnO nanowires operated in atmospheric air to realize continuous corona discharge excited by hundreds of volts. ZnO nanowires were synthesized on microelectrodes using electric-field-assisted wet chemical method, and a thin tungsten film was deposited on the microchip to enhance discharging performance. The testing results showed that the corona inception voltages were minimized greatly by using nanowires compared to conventional dischargers as a result of the local field enhancement of nanowires. The corona could be continuously generated and self-sustaining. It was proved that the law of corona inception voltage obeyed the conventional Peek's breakdown criterion. An optimal thickness of tungsten film coated over ZnO nanowires was figured out to obtain the lowest corona inception voltage. The ion concentration of the nanowire-based discharger attained 10(17)/m(3) orders of magnitude, which is practicable for most discharging applications. PMID:26880727

  1. Recent Studies of the Behavior of the Sun's White-Light Corona Over Time

    NASA Technical Reports Server (NTRS)

    SaintCyr, O. C.; Young, D. E.; Pesnell, W. D.; Lecinski, A.; Eddy, J.

    2008-01-01

    Predictions of upcoming solar cycles are often related to the nature and dynamics of the Sun's polar magnetic field and its influence on the corona. For the past 30 years we have a more-or-less continuous record of the Sun's white-light corona from groundbased and spacebased coronagraphs. Over that interval, the large scale features of the corona have varied in what we now consider a 'predictable' fashion--complex, showing multiple streamers at all latitudes during solar activity maximum; and a simple dipolar shape aligned with the rotational pole during solar minimum. Over the past three decades the white-light corona appears to be a better indicator of 'true' solar minimum than sunspot number since sunspots disappear for months (even years) at solar minimum. Since almost all predictions of the timing of the next solar maximum depend on the timing of solar minimum, the white-light corona is a potentially important observational discriminator for future predictors. In this contribution we describe recent work quantifying the large-scale appearance of the Sun's corona to correlate it with the sunspot record, especially around solar minimum. These three decades can be expanded with the HAO archive of eclipse photographs which, although sparse compared to the coronagraphic coverage, extends back to 1869. A more extensive understanding of this proxy would give researchers confidence in using the white-light corona as an indicator of solar minimum conditions.

  2. Geology of coronae and domal structures on Venus and models of their origin

    SciTech Connect

    Stofan, E.R.

    1989-01-01

    Coronae (160 to 670 km across) and domal structures (greater than 1000 km across) are complex topographic highs on Venus that were affected by volcanic and topographic processes. The geology of coronae and a major domal structure, Beta Regio, are documented using Pioneer Venus, Arecibo, and Venera 15/16 data. The evolution and possible models of origin of these features are also investigated. Beta Regio is a 2000 x 2300 km topographic high located in the equatorial region of Venus that rises over 5 km above the surrounding region. Within Beta Regio lie two large volcanic shields, Theia and Rhea Mons. Coronae are circular to elongate structures on Venus, characterized by an annulus of concentric compressional ridges and relatively raised topography surrounded by a peripheral trough. Volcanic domes, flows and edifices, as well as tectonic lineaments characterize the interiors of coronae. Thirty one coronae were detected on Venus. Two analytical models were developed that are consistent with the general characteristics and evolution of coronae: hotspot or rising mantle diapir model and sinking mantle diapir model. Coronae appear to be part of a continuum of thermally produced features on Venus, along with volcanic complexes and domal structures such as Beta Regio.

  3. ZnO Nanowire-Based Corona Discharge Devices Operated Under Hundreds of Volts

    NASA Astrophysics Data System (ADS)

    Yang, Wenming; Zhu, Rong; Zong, Xianli

    2016-02-01

    Minimizing the voltage of corona discharges, especially when using nanomaterials, has been of great interest in the past decade or so. In this paper, we report a new corona discharge device by using ZnO nanowires operated in atmospheric air to realize continuous corona discharge excited by hundreds of volts. ZnO nanowires were synthesized on microelectrodes using electric-field-assisted wet chemical method, and a thin tungsten film was deposited on the microchip to enhance discharging performance. The testing results showed that the corona inception voltages were minimized greatly by using nanowires compared to conventional dischargers as a result of the local field enhancement of nanowires. The corona could be continuously generated and self-sustaining. It was proved that the law of corona inception voltage obeyed the conventional Peek's breakdown criterion. An optimal thickness of tungsten film coated over ZnO nanowires was figured out to obtain the lowest corona inception voltage. The ion concentration of the nanowire-based discharger attained 1017/m3 orders of magnitude, which is practicable for most discharging applications.

  4. In Support of Failure

    ERIC Educational Resources Information Center

    Carr, Allison

    2013-01-01

    In this essay, I propose a concerted effort to begin devising a theory and pedagogy of failure. I review the discourse of failure in Western culture as well as in composition pedagogy, ultimately suggesting that failure is not simply a judgement or indication of rank but is a relational, affect-bearing concept with tremendous relevance to…

  5. Ammonia tank failure

    SciTech Connect

    Sweat, M.E.

    1983-04-01

    An ammonia tank failure at Hawkeye Chemical of Clinton, Iowa is discussed. The tank was a double-wall, 27,000 metric-ton tank built in 1968 and commissioned in December 1969. The paper presented covers the cause of the failure, repair, and procedural changes made to prevent recurrence of the failure. (JMT)

  6. Magnetic loops, downflows, and convection in the solar corona

    NASA Technical Reports Server (NTRS)

    Foukal, P.

    1978-01-01

    Optical and extreme-ultraviolet observations of solar loop structures show that flows of cool plasma from condensations near the loop apex are a common property of loops associated with radiations whose maximum temperature is greater than approximately 7000 K and less than approximately 3,000,000 K. It is suggested that the mass balance of these structures indicates reconnection by means of plasma motion across field lines under rather general circumstances (not only after flares). It is shown that the cool material has lower gas pressure than the surrounding coronal medium. The density structure of the bright extreme ultraviolet loops suggests that downflows of cool gas result from isobaric condensation of plasma that is either out of thermal equilibrium with the local energy deposition rate into the corona, or is thermally unstable. The evidence is thought to indicate that magnetic fields act to induce a pattern of forced convection.

  7. Clementine Observes the Moon, Solar Corona, and Venus

    NASA Technical Reports Server (NTRS)

    1997-01-01

    In 1994, during its flight, the Clementine spacecraft returned images of the Moon. In addition to the geologic mapping cameras, the Clementine spacecraft also carried two Star Tracker cameras for navigation. These lightweight (0.3 kg) cameras kept the spacecraft on track by constantly observing the positions of stars, reminiscent of the age-old seafaring tradition of sextant/star navigation. These navigation cameras were also to take some spectacular wide angle images of the Moon.

    In this picture the Moon is seen illuminated solely by light reflected from the Earth--Earthshine! The bright glow on the lunar horizon is caused by light from the solar corona; the sun is just behind the lunar limb. Caught in this image is the planet Venus at the top of the frame.

  8. VARIABLE WINDS AND DUST FORMATION IN R CORONAE BOREALIS STARS

    SciTech Connect

    Clayton, Geoffrey C.; Zhang Wanshu; Geballe, T. R. E-mail: wzhan21@lsu.edu

    2013-08-01

    We have observed P-Cygni and asymmetric, blue-shifted absorption profiles in the He I {lambda}10830 lines of 12 R Coronae Borealis stars over short (1 month) and long (3 yr) timescales to look for variations linked to their dust-formation episodes. In almost all cases, the strengths and terminal velocities of the line vary significantly and are correlated with dust formation events. Strong absorption features with blue-shifted velocities {approx}400 km s{sup -1} appear during declines in visible brightness and persist for about 100 days after recovery to maximum brightness. Small residual winds of somewhat lower velocity are present outside of the decline and recovery periods. The correlations support models in which recently formed dust near the star is propelled outward at high speed by radiation pressure and drags the gas along with it.

  9. Structures in the Algol Corona: Searching for Flare Eclipses

    NASA Astrophysics Data System (ADS)

    Favata, Fabio

    Our recent successful observation of a total eclipse of a large flare on Algol (with BeppoSAX) has demonstrated the diagnostic power of flare eclipses, allowing for the first time to derive the size of the coronal structure responsible for a stellar flare (and thus by inference the size of coronal structures in general) on purely geometrical grounds. The loop is compact, much smaller than deduced by the analysis of the flare decay, and located on the pole of the active star. We propose to observe Algol for two binary orbits searching for similar flare eclipses. Further detections of flare eclipses (for which RXTE, with its large effective area is ideally suited) will allow to directly constrain the characteristic sized of structures in the Algol corona.

  10. A New Diagnostic Technique for the Solar Corona

    NASA Technical Reports Server (NTRS)

    Nelson, R.; Davila, Joseph M.; St.Cyr, O. C.; Oegerle, William (Technical Monitor)

    2002-01-01

    Over the last 30-40 years spectroscopic observation of the EUV (extreme ultraviolet) line emission has proved invaluable as a diagnostic of the solar coronal plasma state. Line ratios have been used to determine electron density, electron temperature and ion flow velocity. In this paper, we present results obtained with a new measurement technique that uses spectroscopic observations of the white light corona to obtain the electron density, temperature, and flow velocity. A prototype instrument has been designed and built to obtain visible light spectra (3800-4300 A) with modest resolution. This instrument was used to obtain coronal observations during the June 2001 eclipse in Zambia. The data were corrected for sky and instrument transmission to derive the electron temperature and flow speed. Results from these measurements will be discussed.

  11. Psychosis post corona radiata and lentiform nucleus infarction.

    PubMed

    Abdullah, Khadijah Hasanah Abang; Saini, Suriati Mohamed; Sharip, Shalisah; Rahman, Abdul Hamid Abdul

    2015-04-02

    Complications of stroke can include neuropsychiatric symptoms. However, post-stroke psychosis is rare. We report a case where an acute presentation of psychosis, depression and fluctuating cognitive impairment in a middle-aged man turned out to be related to a silent brain infarction. The patient had a background of poorly controlled type 2 diabetes mellitus with glycated haemoglobin level of 9.0-11.0%, hypertension and ischaemic heart disease. His CT brain results showed multifocal infarct with hypodensities at bilateral lentiform nucleus and bilateral corona radiata. His strong genetic predisposition of psychosis and a history of brief psychotic disorder with complete remission 3 years prior to the current presentation might possibly contribute to his post-stroke atypical neuropsychiatric presentation, and posed diagnostic challenges. He showed marked improvement with risperidone 6 mg nocte, chlorpromazine 50 mg nocte and fluvoxamine of 200 mg nocte. The need of comprehensive treatments to modify his stroke risk factors was addressed.

  12. Basic results of the CORONAS-F solar observations

    NASA Astrophysics Data System (ADS)

    Kuznetsov, V. D.

    2006-08-01

    142190 Troitsk, Moscow Region, Russia V.D. Kuznetsov N.V.Pushkov Institute of Terrestrial Magnetism, Ionosphere and Radio Wave Propagation, Troitsk, Russia The report contains a review of the basic results of the CORONAS-F solar observations during the period of orbital operation of the satellite (from July 31, 2001 to December 6, 2005). Basic results are related with helioseismic observations of the Sun, with localization and study of the morphology of numerous active phenomena in the Sun, including the outstanding events in the declining phase of the solar cycle; with spectroscopic diagnostics of the coronal and flare-generated plasma; with the study of the atomic and nuclear processes in solar flares; with detection of the fluxes of solar cosmic rays, gamma-rays, and neutrons from the major flares reaching the Earth's orbit.

  13. Radiative transfer of X-rays in the solar corona

    NASA Technical Reports Server (NTRS)

    Acton, L. W.

    1978-01-01

    The problem of resonance scattering of X-ray emission lines in the solar corona is investigated. For the resonance lines of some helium-like ions, significant optical depths are reached over distances small compared with the size of typical coronal features. A general integral equation for the transfer of resonance-line radiation under solar coronal conditions is derived. This expression is in a form useful for modeling the complex three-dimensional temperature and density structure of coronal active regions. The transfer equation is then cast in a form illustrating the terms which give rise to the attenuation or enhancement of the resonance-line intensity. The source function for helium-like oxygen (O VII) under coronal conditions is computed and discussed in terms of the relative importance of scattering.

  14. Partial oxidation of methane by pulsed corona discharges

    NASA Astrophysics Data System (ADS)

    Hoeben, W. F. L. M.; Boekhoven, W.; Beckers, F. J. C. M.; van Heesch, E. J. M.; Pemen, A. J. M.

    2014-09-01

    Pulsed corona-induced partial oxidation of methane in humid oxygen or carbon dioxide atmospheres has been investigated for future fuel synthesis applications. The obtained product spectrum is wide, i.e. saturated, unsaturated and oxygen-functional hydrocarbons. The generally observed methane conversion levels are 6-20% at a conversion efficiency of about 100-250 nmol J-1. The main products are ethane, ethylene and acetylene. Higher saturated hydrocarbons up to C6 have been detected. The observed oxygen-functional hydrocarbons are methanol, ethanol and lower concentrations of aldehydes, ketones, dimethylether and methylformate. Methanol seems to be exclusively produced with CH4/O2 mixtures at a maximum production efficiency of 0.35 nmol J-1. CH4/CO2 mixtures appear to yield higher hydrocarbons. Carboxylic acids appear to be mainly present in the aqueous reactor phase, possibly together with higher molecular weight species.

  15. Corona Mass Ejections: a Summary of Recent Results

    NASA Astrophysics Data System (ADS)

    Gopalswamy, N.

    2010-12-01

    Corona mass ejections (CMEs) have been Recognized as the most energetic phenomenon in the heliosphere, deriving their energy from the stressed magnetic fields on the Sun. This paper highlights some of the recent results obtained on CMEs from the Solar and Heliospheric Observatory (SOHO) and the Solar Terrestrial Relations Observatory (STEREO) missions. The summary of follows the talk. SOHO observations revealed that the CME rate is almost a factor of: Two larger than previously thought and varied with the solar activity cycle in a complex way (eg, high-latitude CMEs occurred in great abundance during the solar years maximum). CMEs were found to interact with other CMEs as well as with other large-scale structures (corona holes), Resulting in deflections and additional particle acceleration. STEREO observations have confirmed the three-dimensional nature of CMEs and shocks the surrounding them. The EUV signatures (flare arcades, Corona dimming, filament Eruption, and EUV waves) associated with CMEs have become vital in the identification of sources from Which solar CMEs erupt. CMEs with speeds exceeding the characteristic speeds of the corona and the interplanetary medium drive shocks, which produce type II radio bursts. The wavelength range of type II bursts depends on the CME kinetic energy: type II bursts with emission components at all wavelengths (metric to kilometric) due to CMEs are of the highest kinetic energy. Some CMEs, as fast as 1600 km / s do not produce type II bursts, while slow CMEs (400 km / s) occasionally produce type II bursts. These observations can be explained as the variation in the ambient flow speed (solar wind) speed and the Alfvén. Not all CME-driven shocks produce type II bursts because they are either subcritical Or do not have the appropriate geometry. The same shocks that produce type II bursts also produce solar energetic particles (SEPS), Whose release near the Sun seems to be delayed with respect to the onset of type II bursts

  16. Observational evidence for a hot gaseous Galactic corona

    NASA Technical Reports Server (NTRS)

    Savage, B. D.; De Boer, K. S.

    1979-01-01

    Galactic absorption features observed in high-dispersion far-UV spectra of two Large Magellanic Cloud (LMC) stars obtained with the IUE satellite are discussed. The stars observed were HD 38268 (OB + WN5) and HD 38282 (WN6), which lie at a distance of about 55 kpc and in the galactic direction corresponding to a latitude of about -32 deg and a longitude of about 280 deg. The line of sight to these stars passes through the disk and halo of the Milky Way and the halo and disk of the LMC. Evidence is presented for the existence of a hot (somewhat below 1 million K), low-density (about 0.001 H atom per cu cm) Galactic corona.

  17. Evidence for hot gaseous coronae around the Magellanic Clouds

    NASA Technical Reports Server (NTRS)

    De Boer, K. S.; Savage, B. D.

    1980-01-01

    High-dispersion IUE far-UV spectra were obtained for five stars in the LMC and two stars in the SMC. At Magellanic Cloud velocities, all the spectra exhibit very strong interstellar lines of Al III, Si IV, and C IV, in addition to the usual lower ionization stage lines associated with H I region absorption. In two stars interstellar N V is also detected at the 50 mA level. From a consideration of the strength, width, and radial velocity of these high ionization stage lines, it is argued that regions of hot halo gas have probably been detected in front of the Magellanic Clouds. The regions detected exhibit absorption characteristics very similar to that of the Milky Way corona described previously by Savage and de Boer (1979). A cloud detected in the line of sight to HD 5980 in the SMC at a radial velocity of 300 km/s is of unknown origin.

  18. [Incremental approach to hemodialysis: twice a week, or once weekly hemodialysis combined with low-protein low-phosphorus diet?].

    PubMed

    Bolasco, Piergiorgio; Caria, Stefania; Egidi, Maria Francesca; Cupisti, Adamasco

    2015-01-01

    The start of dialysis treatment is a critical step in the care management of chronic renal failure patients. When hemodialysis is performed three times a week, rapid loss of kidney function and of urine volume output generally occur and this represents an unfavorable prognostic factor. Instead, reducing frequency of hemodialysis sessions, as well as peritoneal dialysis, can contribute to a lesser decrease of residual renal function. Unfortunately, the existing protocols for an incremental hemodialysis approach are not particularly common and they are generally limited to a twice a week hemodialysis schedule. In addition to clinical and economic reasons, an incremental approach to ESRD also contributes to better social and psychological adaptation by the patients to the dramatic change in living conditions linked to the maintenance dialysis treatment. In patients who have attitude for low-protein nutritional therapy, a once weekly dialysis schedule combined with low-protein, low-phosphorus, normal to high energy diet in the remaining six days of the week can be implemented in selected patients. In our experience, this kind of program produced important clinical results and reduction in costs and hospitalization. When compared with a three times a week dialysis schedule, a greater protection of residual renal function and of urine volume output, lower increase in 2 microglobulin, better control of phosphorus and less consumption of phosphate binders and erythropoietin were observed. Careful clinical monitoring and nutrition is essential for the safety and optimization of infrequent hemodialysis. Long-term follow-up analysis shows favorable effects on the overall survival. Furthermore, twice a week hemodialysis is not the only option for an incremental approach of dialysis commencing. In patients who have a good attitude for low-protein nutritional therapy, its arrangement with a program of once weekly dialysis represents a real and effective alternative. PMID

  19. Processes of carbon disulfide degradation under the action of a pulsed corona discharge

    NASA Astrophysics Data System (ADS)

    Kuznetsov, D. L.; Filatov, I. E.; Uvarin, V. V.

    2016-08-01

    Experiments on decomposition of carbon disulfide CS2 in air under the action of a pulsed nanosecond corona discharge have been carried out. The energetic efficiency of the degradation amounted to 290-340 g (kW h)-1, which is significantly higher than with the use of a corona discharge at a constant voltage. The main degradation products are sulfur dioxide SO2, carbonyl sulfide COS, sulfuric acid, and carbon dioxide. Processes occurring in pulsed corona discharge plasma and leading to carbon disulfide degradation are considered. Different methods of air purification from carbon disulfide are compared.

  20. Impact crater densities on volcanoes and coronae on venus: implications for volcanic resurfacing.

    PubMed

    Namiki, N; Solomon, S C

    1994-08-12

    The density of impact craters on large volcanoes on Venus is half the average crater density for the planet. The crater density on some classes of coronae is not significantly different from the global average density, but coronae with extensive associated volcanic deposits have lower crater densities. These results are inconsistent with both single-age and steady-state models for global resurfacing and suggest that volcanoes and coronae with associated volcanism have been active on Venus over the last 500 million years.

  1. Effect of configuration and dimensions of reactor electrodes on electrical and optical corona discharge characteristics

    SciTech Connect

    El-Koramy, Reda Ahmed; Yehia, Ashraf; Omer, Mohamed

    2010-05-15

    An experimental parametric study is made to investigate how the electrical corona discharge characteristics are influenced by the geometrical configuration and dimensions of the reactor and the electrode polarity of the applied voltage. Furthermore, features of the corona discharge plasma formed around the stressed electrode in some different gases are recorded photographically to provide more information on the physical mechanisms of the corona discharge in the investigated gases. The obtained results have been discussed in the light of gas discharge physics and its applications.

  2. On the effects of magnetic field line topology on the energy propagation in the solar corona

    NASA Astrophysics Data System (ADS)

    Candelaresi, Simon

    2016-05-01

    Using the MHD approximation, we study the propagation of energy from photospheric footpoint motions into the corona. Our model consists of a magnetic carpet with closed and open magnetic field lines. Magnetic null points are present close at the surface. The applied photospheric driver twists the field into a topologically non-trivial configuration which leads to reconnection and a change in field line topology. Prior to this event, the energy propagation into the corona is largely inhibited due to closed field lines. After such events the energy is free to propagate into the corona.

  3. In Vivo Biomolecule Corona around Blood-Circulating, Clinically Used and Antibody-Targeted Lipid Bilayer Nanoscale Vesicles.

    PubMed

    Hadjidemetriou, Marilena; Al-Ahmady, Zahraa; Mazza, Mariarosa; Collins, Richard F; Dawson, Kenneth; Kostarelos, Kostas

    2015-08-25

    The adsorption of proteins and their layering onto nanoparticle surfaces has been called the "protein corona". This dynamic process of protein adsorption has been extensively studied following in vitro incubation of many different nanoparticles with plasma proteins. However, the formation of protein corona under dynamic, in vivo conditions remains largely unexplored. Extrapolation of in vitro formed protein coronas to predict the fate and possible toxicological burden from nanoparticles in vivo is of great interest. However, complete lack of such direct comparisons for clinically used nanoparticles makes the study of in vitro and in vivo formed protein coronas of great importance. Our aim was to study the in vivo protein corona formed onto intravenously injected, clinically used liposomes, based on the composition of the PEGylated liposomal formulation that constitutes the anticancer agent Doxil. The formation of in vivo protein corona was determined after the recovery of the liposomes from the blood circulation of CD-1 mice 10 min postinjection. In comparison, in vitro protein corona was formed by the incubation of liposomes in CD-1 mouse plasma. In vivo and in vitro formed protein coronas were compared in terms of morphology, composition and cellular internalization. The protein coronas on bare (non-PEGylated) and monoclonal antibody (IgG) targeted liposomes of the same lipid composition were also comparatively investigated. A network of linear fibrillary structures constituted the in vitro formed protein corona, whereas the in vivo corona had a different morphology but did not appear to coat the liposome surface entirely. Even though the total amount of protein attached on circulating liposomes correlated with that observed from in vitro incubations, the variety of molecular species in the in vivo corona were considerably wider. Both in vitro and in vivo formed protein coronas were found to significantly reduce receptor binding and cellular internalization of

  4. In Vivo Biomolecule Corona around Blood-Circulating, Clinically Used and Antibody-Targeted Lipid Bilayer Nanoscale Vesicles.

    PubMed

    Hadjidemetriou, Marilena; Al-Ahmady, Zahraa; Mazza, Mariarosa; Collins, Richard F; Dawson, Kenneth; Kostarelos, Kostas

    2015-08-25

    The adsorption of proteins and their layering onto nanoparticle surfaces has been called the "protein corona". This dynamic process of protein adsorption has been extensively studied following in vitro incubation of many different nanoparticles with plasma proteins. However, the formation of protein corona under dynamic, in vivo conditions remains largely unexplored. Extrapolation of in vitro formed protein coronas to predict the fate and possible toxicological burden from nanoparticles in vivo is of great interest. However, complete lack of such direct comparisons for clinically used nanoparticles makes the study of in vitro and in vivo formed protein coronas of great importance. Our aim was to study the in vivo protein corona formed onto intravenously injected, clinically used liposomes, based on the composition of the PEGylated liposomal formulation that constitutes the anticancer agent Doxil. The formation of in vivo protein corona was determined after the recovery of the liposomes from the blood circulation of CD-1 mice 10 min postinjection. In comparison, in vitro protein corona was formed by the incubation of liposomes in CD-1 mouse plasma. In vivo and in vitro formed protein coronas were compared in terms of morphology, composition and cellular internalization. The protein coronas on bare (non-PEGylated) and monoclonal antibody (IgG) targeted liposomes of the same lipid composition were also comparatively investigated. A network of linear fibrillary structures constituted the in vitro formed protein corona, whereas the in vivo corona had a different morphology but did not appear to coat the liposome surface entirely. Even though the total amount of protein attached on circulating liposomes correlated with that observed from in vitro incubations, the variety of molecular species in the in vivo corona were considerably wider. Both in vitro and in vivo formed protein coronas were found to significantly reduce receptor binding and cellular internalization of

  5. Buoyant subduction on Venus: Implications for subduction around coronae

    NASA Astrophysics Data System (ADS)

    Burt, J. D.; Head, J. W.

    1993-03-01

    Potentially low lithospheric densities, caused by high Venus surface and perhaps mantle temperatures, could inhibit the development of negative buoyancy-driven subduction and a global system of plate tectonics/crustal recycling on that planet. No evidence for a global plate tectonic system was found so far, however, specific features strongly resembling terrestrial subduction zones in planform and topographic cross-section were described, including trenches around large coronae and chasmata in eastern Aphrodite Terra. The cause for the absence, or an altered expression, of plate tectonics on Venus remains to be found. Slab buoyancy may play a role in this difference, with higher lithospheric temperatures and a tendency toward positive buoyancy acting to oppose the descent of slabs and favoring under thrusting instead. The effect of slab buoyancy on subduction was explored and the conditions which would lead to under thrusting versus those allowing the formation of trenches and self-perpetuating subduction were defined. Applying a finite element code to assess the effects of buoyant forces on slabs subducting into a viscous mantle, it was found that mantle flow induced by horizontal motion of the convergent lithosphere greatly influences subduction angle, while buoyancy forces produce a lesser effect. Induced mantle flow tends to decrease subduction angle to near an under thrusting position when the subducting lithosphere converges on a stationary overriding lithosphere. When the overriding lithosphere is in motion, as in the case of an expanding corona, subduction angles are expected to increase. An initial stage involved estimating the changes in slab buoyancy due to slab healing and pressurization over the course of subduction. Modeling a slab, descending at a fixed angle and heated by conduction, radioactivity, and the heat released in phase changes, slab material density changes due to changing temperature, phase, and pressure were derived.

  6. Remote-sensing Observations of the Corona and Solar Wind

    NASA Astrophysics Data System (ADS)

    Sheeley, Neil R., Jr.

    2009-05-01

    On June 25, 1908, George Ellery Hale used the 60-foot Tower Telescope on Mount Wilson to make the first measurements of magnetic fields in sunspots. This began a series of studies that led to Hale's Law of sunspot polarities and established the Mount Wilson Observatory as a leading center of solar magnetic field research. The magnetic aura was still present in 1962 when I began solar research there as a Caltech graduate student. Mount Wilson astronomer Horace Babcock and his father had invented the solar magnetograph, discovered the polar fields of the Sun, and observed their reversal near the 1958 sunspot maximum. Caltech physicist Robert Leighton had added new instrumentation to the Mount Wilson spectroheliograph and obtained high-resolution maps of the magnetic field. Babcock had just published his classic paper on the topology of the field and its 22-year cycle. The paper contained a sketch, illustrating the coronal field-line reconnection, which he thought must occur in response to changes of the photospheric field. Some loops flew away in the yet-to-be-discovered solar wind and other loops collapsed back to the Sun. In this talk, I will present new observations from the SOHO and STEREO spacecraft, which show such coronal changes. Loops stretch out in the expanding corona and tear away from the Sun like drops from a leaky faucet. Simultaneous observations with different perspectives show that the detached loops are really helices in 3-D. Off-pointed heliospheric imagers allow us to track these ejections outward past planets (including Earth) and comets, and to observe their compression into a heliospheric spiral, as a consequence of longitudinal speed gradients on the rotating Sun. And XUV observations of the solar disk show brightness changes associated with reconnections high in the corona, like auroral displays in the magnetosphere.

  7. 2MASS wide-field extinction maps. V. Corona Australis

    NASA Astrophysics Data System (ADS)

    Alves, João; Lombardi, Marco; Lada, Charles J.

    2014-05-01

    We present a near-infrared extinction map of a large region (~870 deg2) covering the isolated Corona Australis complex of molecular clouds. We reach a 1-σ error of 0.02 mag in the K-band extinction with a resolution of 3 arcmin over the entire map. We find that the Corona Australis cloud is about three times as large as revealed by previous CO and dust emission surveys. The cloud consists of a 45 pc long complex of filamentary structure from the well known star forming Western-end (the head, N ≥ 1023 cm-2) to the diffuse Eastern-end (the tail, N ≤ 1021 cm-2). Remarkably, about two thirds of the complex both in size and mass lie beneath AV ~ 1 mag. We find that the probability density function (PDF) of the cloud cannot be described by a single log-normal function. Similar to prior studies, we found a significant excess at high column densities, but a log-normal + power-law tail fit does not work well at low column densities. We show that at low column densities near the peak of the observed PDF, both the amplitude and shape of the PDF are dominated by noise in the extinction measurements making it impractical to derive the intrinsic cloud PDF below AK < 0.15 mag. Above AK ~ 0.15 mag, essentially the molecular component of the cloud, the PDF appears to be best described by a power-law with index -3, but could also described as the tail of a broad and relatively low amplitude, log-normal PDF that peaks at very low column densities. FITS files of the extinction maps are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/565/A18

  8. Decontamination of 2-Chloroethyl Ethyl Sulfide by Pulsed Corona Plasma

    NASA Astrophysics Data System (ADS)

    Li, Zhanguo; Hu, Zhen; Cao, Peng; Zhao, Hongjie

    2014-11-01

    Decontamination of 2-chloroethyl ethyl sulfide (2-CEES, CH3CH2SCH2CH2Cl) by pulsed corona plasma was investigated. The results show that 212.6 mg/m3 of 2-CEES, with the gas flow rate of 2 m3/h, can be decontaminated to 0.09 mg/m3. According to the variation of the inlet and outlet concentration of 2-CEES vapor with retention time, it is found that the reaction of 2-CEES in a pulsed corona plasma system follows the first order reaction, with the reaction rate constant of 0.463 s-1. The decontamination mechanism is discussed based on an analysis of the dissociation energy of chemical bonds and decontamination products. The C-S bond adjacent to the Cl atom will be destroyed firstly to form CH3CH2S· and ·CH2CH2Cl radicals. CH3CH2S· can be decomposed to ·C2H5 and ·S. ·S can be oxidized to SO2, while ·C2H5 can be finally oxidized to CO2 and H2O. The C-Cl bond in the ·CH2CH2Cl radical can be destroyed to form ·CH2CH2. and ·Cl, which can be mineralized to CO2, H2O and HCl. The H atom in the ·CH2CH2Cl radical can also be substituted by ·Cl to form CHCl2-CHCl2.

  9. RADIO OBSERVATIONS OF WEAK ENERGY RELEASES IN THE SOLAR CORONA

    SciTech Connect

    Ramesh, R.; Kathiravan, C.; Barve, Indrajit V.; Beeharry, G. K.; Rajasekara, G. N.

    2010-08-10

    We report observations of weak, circularly polarized, structureless type III bursts from the solar corona in the absence of H{alpha}/X-ray flares and other related activity, during the minimum between the sunspot cycles 23 and 24. The spectral information about the event obtained with the CALLISTO spectrograph at Mauritius revealed that the drift rate of the burst is {approx}-30 MHz s{sup -1} is in the range 50-120 MHz. Two-dimensional imaging observations of the burst at 77 MHz obtained with the Gauribidanur radioheliograph indicate that the emission region was located at a radial distance of {approx}1.5 R{sub sun} in the solar atmosphere. The estimated peak brightness temperature of the burst at 77 MHz is {approx}10{sup 8} K. We derived the average magnetic field at the aforementioned location of the burst using the one-dimensional (east-west) Gauribidanur radio polarimeter at 77 MHz, and the value is {approx}2.5 {+-} 0.2 G. We also estimated the total energy of the non-thermal electrons responsible for the observed burst as {approx}1.1 x 10{sup 24} erg. This is low compared to the energy of the weakest hard X-ray microflares reported in the literature, which is about {approx}10{sup 26} erg. The present result shows that non-thermal energy releases that correspond to the nanoflare category (energy {approx}10{sup 24} erg) are taking place in the solar corona, and the nature of such small-scale energy releases has not yet been explored.

  10. WHAT IS THE SHELL AROUND R CORONAE BOREALIS?

    SciTech Connect

    Montiel, Edward J.; Clayton, Geoffrey C.; Marcello, Dominic C.; Lockman, Felix J. E-mail: gclayton@fenway.phys.lsu.edu E-mail: jlockman@nrao.edu

    2015-07-15

    The hydrogen-deficient, carbon-rich R Coronae Borealis (RCB) stars are known for being prolific producers of dust which causes their large iconic declines in brightness. Several RCB stars, including R Coronae Borealis (R CrB), itself, have large extended dust shells seen in the far-infrared. The origin of these shells is uncertain but they may give us clues to the evolution of the RCB stars. The shells could form in three possible ways. (1) They are fossil Planetary Nebula (PN) shells, which would exist if RCB stars are the result of a final, helium-shell flash, (2) they are material left over from a white-dwarf (WD) merger event which formed the RCB stars, or (3) they are material lost from the star during the RCB phase. Arecibo 21 cm observations establish an upper limit on the column density of H I in the R CrB shell implying a maximum shell mass of ≲0.3 M{sub ☉}. A low-mass fossil PN shell is still a possible source of the shell although it may not contain enough dust. The mass of gas lost during a WD merger event will not condense enough dust to produce the observed shell, assuming a reasonable gas-to-dust ratio. The third scenario where the shell around R CrB has been produced during the star’s RCB phase seems most likely to produce the observed mass of dust and the observed size of the shell. But this means that R CrB has been in its RCB phase for ∼10{sup 4} years.

  11. On the Origin of Magnetic Helicity in the Solar Corona

    NASA Astrophysics Data System (ADS)

    Tian, Lirong; Alexander, David

    2008-01-01

    Twenty-three active regions associated with pronounced sigmoidal structure in Yohkoh soft X-ray observations are selected to investigate the origin of magnetic helicity in the solar corona. We calculate the radial magnetic flux of each polarity, the rate of magnetic helicity injection, and total flux of the helicity injection (Δ HLCT) over 4-5 days using MDI 96 minute line-of-sight magnetograms and a local correlation tracking technique. We also estimate the contribution from differential rotation to the overall helicity budget (Δ Hrot). It is found that of the seven active regions for which the flux emergence exceeds 1.0 × 1022 Mx, six exhibited a helicity flux injection exceeding 1.0 × 1043 Mx2 (i.e., Δ H = Δ HLCT - Δ Hrot). Moreover, the rate of helicity injection and the total helicity flux are larger (smaller) during periods of more (less) increase of magnetic flux. Of the remaining 16 active regions, with flux emergence less than 1022 Mx, only 4 had significant injection of helicity, exceeding 1043 Mx2. Typical contributions from differential rotation over the same period were 2-3 times smaller than that of the strong magnetic field emergence. These statistical results signify that the strong emergence of magnetic field is the most important origin of the coronal helicity, while horizontal motions and differential rotation are insufficient to explain the measured helicity injection flux. Furthermore, the study of the helicity injection in nineteen newly emerging active regions confirms the result on the important role played by strong magnetic flux emergence in controlling the injection of magnetic helicity into the solar corona.

  12. Distribution of electric currents in sunspots from photosphere to corona

    SciTech Connect

    Gosain, Sanjay; Démoulin, Pascal; López Fuentes, Marcelo

    2014-09-20

    We present a study of two regular sunspots that exhibit nearly uniform twist from the photosphere to the corona. We derive the twist parameter in the corona and in the chromosphere by minimizing the difference between the extrapolated linear force-free field model field lines and the observed intensity structures in the extreme-ultraviolet images of the Sun. The chromospheric structures appear more twisted than the coronal structures by a factor of two. Further, we derive the vertical component of electric current density, j{sub z} , using vector magnetograms from the Hinode Solar Optical Telescope (SOT). The spatial distribution of j{sub z} has a zebra pattern of strong positive and negative values owing to the penumbral fibril structure resolved by Hinode/SOT. This zebra pattern is due to the derivative of the horizontal magnetic field across the thin fibrils; therefore, it is strong and masks weaker currents that might be present, for example, as a result of the twist of the sunspot. We decompose j{sub z} into the contribution due to the derivatives along and across the direction of the horizontal field, which follows the fibril orientation closely. The map of the tangential component has more distributed currents that are coherent with the chromospheric and coronal twisted structures. Moreover, it allows us to map and identify the direct and return currents in the sunspots. Finally, this decomposition of j{sub z} is general and can be applied to any vector magnetogram in order to better identify the weaker large-scale currents that are associated with coronal twisted/sheared structures.

  13. THE EXPANSION OF ACTIVE REGIONS INTO THE EXTENDED SOLAR CORONA

    SciTech Connect

    Morgan, Huw; Jeska, Lauren; Leonard, Drew

    2013-06-01

    Advanced image processing of Large Angle and Spectrometric Coronagraph Experiment (LASCO) C2 observations reveals the expansion of the active region closed field into the extended corona. The nested closed-loop systems are large, with an apparent latitudinal extent of 50 Degree-Sign , and expanding to heights of at least 12 R{sub Sun }. The expansion speeds are {approx}10 km s{sup -1} in the AIA/SDO field of view, below {approx}20 km s{sup -1} at 2.3 R{sub Sun }, and accelerate linearly to {approx}60 km s{sup -1} at 5 R{sub Sun }. They appear with a frequency of one every {approx}3 hr over a time period of around three days. They are not coronal mass ejections (CMEs) since their gradual expansion is continuous and steady. They are also faint, with an upper limit of 3% of the brightness of background streamers. Extreme ultraviolet images reveal continuous birth and expansion of hot, bright loops from a new active region at the base of the system. The LASCO images show that the loops span a radial fan-like system of streamers, suggesting that they are not propagating within the main coronal streamer structure. The expanding loops brighten at low heights a few hours prior to a CME eruption, and the expansion process is temporarily halted as the closed field system is swept away. Closed magnetic structures from some active regions are not isolated from the extended corona and solar wind, but can expand to large heights in the form of quiescent expanding loops.

  14. The failure of earthquake failure models

    USGS Publications Warehouse

    Gomberg, J.

    2001-01-01

    In this study I show that simple heuristic models and numerical calculations suggest that an entire class of commonly invoked models of earthquake failure processes cannot explain triggering of seismicity by transient or "dynamic" stress changes, such as stress changes associated with passing seismic waves. The models of this class have the common feature that the physical property characterizing failure increases at an accelerating rate when a fault is loaded (stressed) at a constant rate. Examples include models that invoke rate state friction or subcritical crack growth, in which the properties characterizing failure are slip or crack length, respectively. Failure occurs when the rate at which these grow accelerates to values exceeding some critical threshold. These accelerating failure models do not predict the finite durations of dynamically triggered earthquake sequences (e.g., at aftershock or remote distances). Some of the failure models belonging to this class have been used to explain static stress triggering of aftershocks. This may imply that the physical processes underlying dynamic triggering differs or that currently applied models of static triggering require modification. If the former is the case, we might appeal to physical mechanisms relying on oscillatory deformations such as compaction of saturated fault gouge leading to pore pressure increase, or cyclic fatigue. However, if dynamic and static triggering mechanisms differ, one still needs to ask why static triggering models that neglect these dynamic mechanisms appear to explain many observations. If the static and dynamic triggering mechanisms are the same, perhaps assumptions about accelerating failure and/or that triggering advances the failure times of a population of inevitable earthquakes are incorrect.

  15. Incremental triangulation by way of edge swapping and local optimization

    NASA Technical Reports Server (NTRS)

    Wiltberger, N. Lyn

    1994-01-01

    This document is intended to serve as an installation, usage, and basic theory guide for the two dimensional triangulation software 'HARLEY' written for the Silicon Graphics IRIS workstation. This code consists of an incremental triangulation algorithm based on point insertion and local edge swapping. Using this basic strategy, several types of triangulations can be produced depending on user selected options. For example, local edge swapping criteria can be chosen which minimizes the maximum interior angle (a MinMax triangulation) or which maximizes the minimum interior angle (a MaxMin or Delaunay triangulation). It should be noted that the MinMax triangulation is generally only locally optical (not globally optimal) in this measure. The MaxMin triangulation, however, is both locally and globally optical. In addition, Steiner triangulations can be constructed by inserting new sites at triangle circumcenters followed by edge swapping based on the MaxMin criteria. Incremental insertion of sites also provides flexibility in choosing cell refinement criteria. A dynamic heap structure has been implemented in the code so that once a refinement measure is specified (i.e., maximum aspect ratio or some measure of a solution gradient for the solution adaptive grid generation) the cell with the largest value of this measure is continually removed from the top of the heap and refined. The heap refinement strategy allows the user to specify either the number of cells desired or refine the mesh until all cell refinement measures satisfy a user specified tolerance level. Since the dynamic heap structure is constantly updated, the algorithm always refines the particular cell in the mesh with the largest refinement criteria value. The code allows the user to: triangulate a cloud of prespecified points (sites), triangulate a set of prespecified interior points constrained by prespecified boundary curve(s), Steiner triangulate the interior/exterior of prespecified boundary curve

  16. Ventilation behavior during upper-body incremental exercise.

    PubMed

    Pires, Flávio O; Hammond, John; Lima-Silva, Adriano E; Bertuzzi, Rômulo C M; Kiss, Maria Augusta P D M

    2011-01-01

    This study tested the ventilation (VE) behavior during upper-body incremental exercise by mathematical models that calculate 1 or 2 thresholds and compared the thresholds identified by mathematical models with V-slope, ventilatory equivalent for oxygen uptake (VE/V(O2)), and ventilatory equivalent for carbon dioxide uptake (VE/V(CO2)). Fourteen rock climbers underwent an upper-body incremental test on a cycle ergometer with increases of approximately 20 W · min(-1) until exhaustion at a cranking frequency of approximately 90 rpm. The VE data were smoothed to 10-second averages for VE time plotting. The bisegmental and the 3-segmental linear regression models were calculated from 1 or 2 intercepts that best shared the VE curve in 2 or 3 linear segments. The ventilatory threshold(s) was determined mathematically by the intercept(s) obtained by bisegmental and 3-segmental models, by V-slope model, or visually by VE/V(O2) and VE/V(CO2). There was no difference between bisegmental (mean square error [MSE] = 35.3 ± 32.7 l · min(-1)) and 3-segmental (MSE = 44.9 ± 47.8 l · min(-1)) models in fitted data. There was no difference between ventilatory threshold identified by the bisegmental (28.2 ± 6.8 ml · kg(-1) · min(-1)) and second ventilatory threshold identified by the 3-segmental (30.0 ± 5.1 ml · kg(-1) · min(-1)), VE/V(O2) (28.8 ± 5.5 ml · kg(-1) · min(-1)), or V-slope (28.5 ± 5.6 ml · kg(-1) . min(-1)). However, the first ventilatory threshold identified by 3-segmental (23.1 ± 4.9 ml · kg(-1) · min(-1)) or by VE/V(O)2 (24.9 ± 4.4 ml · kg(-1) · min(-1)) was different from these 4. The VE behavior during upper-body exercise tends to show only 1 ventilatory threshold. These findings have practical implications because this point is frequently used for aerobic training prescription in healthy subjects, athletes, and in elderly or diseased populations. The ventilatory threshold identified by VE curve should be used for aerobic training prescription in

  17. Failure? Isn't It Time to Slay the Design-Dragon?

    ERIC Educational Resources Information Center

    Winkler, Dietmar R.

    2009-01-01

    There is a closed cycle of design education that replicates the most common design practice--and feeds into that practice that seeks awards based on incremental change supported by professional organizations and trade journals--that feeds back to education forms for imitation. This is the educational failure this paper cites. It takes to task the…

  18. Incremental truncation of PHA synthases results in altered product specificity.

    PubMed

    Wang, Qian; Xia, Yongzhen; Chen, Quan; Qi, Qingsheng

    2012-05-10

    PHA synthase is the key enzyme involved in the biosynthesis of microbial polymers, polyhydroxyalkanoates (PHA). In this study, we created a hybrid library of PHA synthase gene with different crossover points by an incremental truncation method between the C-terminal fragments of the phaC(Cn) (phaC from Cupriavidus necator) and the N-terminal fragments of the phaC1(Pa) (phaC from Pseudomonas aeruginosa). As the truncation of the hybrid enzyme increased, the in vivo PHB synthesis ability of the hybrids declined gradually. PHA synthase PhaC(Cn) with a deletion on N-terminal up to 83 amino acid residues showed no synthase activity. While with the removal of up to 270 amino acids from the N-terminus, the activity of the truncated PhaC(Cn) could be complemented by the N-terminus of PhaC1(Pa). Three of the hybrid enzymes W188, W235 and W272 (named by the deleted nucleic acid number) were found to have altered product specificities. PMID:22500895

  19. Noise masking of S-cone increments and decrements

    PubMed Central

    Wang, Quanhong; Richters, David P.; Eskew, Rhea T.

    2014-01-01

    S-cone increment and decrement detection thresholds were measured in the presence of bipolar, dynamic noise masks. Noise chromaticities were the L-, M-, and S-cone directions, as well as L−M, L+M, and achromatic (L+M+S) directions. Noise contrast power was varied to measure threshold Energy versus Noise (EvN) functions. S+ and S− thresholds were similarly, and weakly, raised by achromatic noise. However, S+ thresholds were much more elevated by S, L+M, L–M, L- and M-cone noises than were S− thresholds, even though the noises consisted of two symmetric chromatic polarities of equal contrast power. A linear cone combination model accounts for the overall pattern of masking of a single test polarity well. L and M cones have opposite signs in their effects upon raising S+ and S− thresholds. The results strongly indicate that the psychophysical mechanisms responsible for S+ and S− detection, presumably based on S-ON and S-OFF pathways, are distinct, unipolar mechanisms, and that they have different spatiotemporal sampling characteristics, or contrast gains, or both. PMID:25391300

  20. An incremental database access method for autonomous interoperable databases

    NASA Technical Reports Server (NTRS)

    Roussopoulos, Nicholas; Sellis, Timos

    1994-01-01

    We investigated a number of design and performance issues of interoperable database management systems (DBMS's). The major results of our investigation were obtained in the areas of client-server database architectures for heterogeneous DBMS's, incremental computation models, buffer management techniques, and query optimization. We finished a prototype of an advanced client-server workstation-based DBMS which allows access to multiple heterogeneous commercial DBMS's. Experiments and simulations were then run to compare its performance with the standard client-server architectures. The focus of this research was on adaptive optimization methods of heterogeneous database systems. Adaptive buffer management accounts for the random and object-oriented access methods for which no known characterization of the access patterns exists. Adaptive query optimization means that value distributions and selectives, which play the most significant role in query plan evaluation, are continuously refined to reflect the actual values as opposed to static ones that are computed off-line. Query feedback is a concept that was first introduced to the literature by our group. We employed query feedback for both adaptive buffer management and for computing value distributions and selectivities. For adaptive buffer management, we use the page faults of prior executions to achieve more 'informed' management decisions. For the estimation of the distributions of the selectivities, we use curve-fitting techniques, such as least squares and splines, for regressing on these values.

  1. Process Parameters Optimization in Single Point Incremental Forming

    NASA Astrophysics Data System (ADS)

    Gulati, Vishal; Aryal, Ashmin; Katyal, Puneet; Goswami, Amitesh

    2016-04-01

    This work aims to optimize the formability and surface roughness of parts formed by the single-point incremental forming process for an Aluminium-6063 alloy. The tests are based on Taguchi's L18 orthogonal array selected on the basis of DOF. The tests have been carried out on vertical machining center (DMC70V); using CAD/CAM software (SolidWorks V5/MasterCAM). Two levels of tool radius, three levels of sheet thickness, step size, tool rotational speed, feed rate and lubrication have been considered as the input process parameters. Wall angle and surface roughness have been considered process responses. The influential process parameters for the formability and surface roughness have been identified with the help of statistical tool (response table, main effect plot and ANOVA). The parameter that has the utmost influence on formability and surface roughness is lubrication. In the case of formability, lubrication followed by the tool rotational speed, feed rate, sheet thickness, step size and tool radius have the influence in descending order. Whereas in surface roughness, lubrication followed by feed rate, step size, tool radius, sheet thickness and tool rotational speed have the influence in descending order. The predicted optimal values for the wall angle and surface roughness are found to be 88.29° and 1.03225 µm. The confirmation experiments were conducted thrice and the value of wall angle and surface roughness were found to be 85.76° and 1.15 µm respectively.

  2. Heat increment of feeding in Steller sea lions, Eumetopias jubatus.

    PubMed

    Rosen, D A; Trites, A W

    1997-11-01

    The heat increment of feeding (HIF) was measured in six captive, juvenile Steller sea lions (Eumetopias jubatus), fed meals of either 2 or 4 kg of herring. HIF was calculated as the post-prandial increase in metabolism above baseline levels, and was measured using open-circuit (gas) respirometry. It averaged 12.4 +/- 0.9% (SE) of ingested energy intake for the 4-kg meal trials, and 9.9 +/- 0.9% for the 2-kg meal size. The effect lasted 8-10 hr for the larger meal size. Metabolism peaked 3.7 hr after feeding, and was 2.13 times higher than baseline levels. For the 2-kg meal size, the effect lasted 6-8 hr, with metabolism peaking 2.8 hr after ingestion at 1.76 times baseline levels. Our estimates of HIF for Steller sea lions are at the lower end of estimates for terrestrial mammals, and are consistent with estimates for other marine mammals. PMID:9406451

  3. A novel instrument for generating angular increments of 1 nanoradian

    NASA Astrophysics Data System (ADS)

    Alcock, Simon G.; Bugnar, Alex; Nistea, Ioana; Sawhney, Kawal; Scott, Stewart; Hillman, Michael; Grindrod, Jamie; Johnson, Iain

    2015-12-01

    Accurate generation of small angles is of vital importance for calibrating angle-based metrology instruments used in a broad spectrum of industries including mechatronics, nano-positioning, and optic fabrication. We present a novel, piezo-driven, flexure device capable of reliably generating micro- and nanoradian angles. Unlike many such instruments, Diamond Light Source's nano-angle generator (Diamond-NANGO) does not rely on two separate actuators or rotation stages to provide coarse and fine motion. Instead, a single Physik Instrumente NEXLINE "PiezoWalk" actuator provides millimetres of travel with nanometre resolution. A cartwheel flexure efficiently converts displacement from the linear actuator into rotary motion with minimal parasitic errors. Rotation of the flexure is directly measured via a Magnescale "Laserscale" angle encoder. Closed-loop operation of the PiezoWalk actuator, using high-speed feedback from the angle encoder, ensures that the Diamond-NANGO's output drifts by only ˜0.3 nrad rms over ˜30 min. We show that the Diamond-NANGO can reliably move with unprecedented 1 nrad (˜57 ndeg) angular increments over a range of >7000 μrad. An autocollimator, interferometer, and capacitive displacement sensor are used to independently confirm the Diamond-NANGO's performance by simultaneously measuring the rotation of a reflective cube.

  4. Warm Forming of Mg Sheets: From Incremental to Electromagnetic Forming

    NASA Astrophysics Data System (ADS)

    Ulacia, Ibai; Galdos, Lander; Esnaola, Jon Ander; Larrañaga, Jon; Arruebarrena, Gurutze; de Argandoña, Eneko Saenz; Hurtado, Iñaki

    2014-07-01

    Magnesium alloys are generating interest in the automotive and aeronautic industries due to their low density and potential to reduce gross vehicular weight. However, the formability of these alloys is poor and they are very difficult to be formed at room temperature due to their strong basal texture in rolled form. In this paper, the potential of magnesium alloy sheets to be processed at warm conditions is studied for four different forming technologies: incremental forming (IF), deep drawing (DD), hydroforming (HF), and electromagnetic forming (EMF). Forming mechanisms and process window are experimentally characterized by monitoring different process parameters. Special focus is made on the influence of the forming temperature and the strain rate. Thus, experiments at temperatures from room to 523 K (250 °C) and a wide range of strain rates, between 10-3 up to 103 s-1 according to each process nature and scope, are conducted. It is observed that, even the inherent forming rate range of each process vary considerably, increasing forming temperature increases formability for all of these forming processes. In the other hand, an opposing effect of the strain rate is observed between the quasi-static processes (IF, DD, and HF) and the high speed process (EMF). Thus, a detrimental effect on formability is observed when increasing strain rate for quasi-static processes, while a mild increase is observed for EMF.

  5. Incremental visual text analytics of news story development

    NASA Astrophysics Data System (ADS)

    Krstajic, Milos; Najm-Araghi, Mohammad; Mansmann, Florian; Keim, Daniel A.

    2012-01-01

    Online news sources produce thousands of news articles every day, reporting on local and global real-world events. New information quickly replaces the old, making it difficult for readers to put current events in the context of the past. Additionally, the stories have very complex relationships and characteristics that are difficult to model: they can be weakly or strongly connected, or they can merge or split over time. In this paper, we present a visual analytics system for exploration of news topics in dynamic information streams, which combines interactive visualization and text mining techniques to facilitate the analysis of similar topics that split and merge over time. We employ text clustering techniques to automatically extract stories from online news streams and present a visualization that: 1) shows temporal characteristics of stories in different time frames with different level of detail; 2) allows incremental updates of the display without recalculating the visual features of the past data; 3) sorts the stories by minimizing clutter and overlap from edge crossings. By using interaction, stories can be filtered based on their duration and characteristics in order to be explored in full detail with details on demand. To demonstrate the usefulness of our system, case studies with real news data are presented and show the capabilities for detailed dynamic text stream exploration.

  6. A novel instrument for generating angular increments of 1 nanoradian.

    PubMed

    Alcock, Simon G; Bugnar, Alex; Nistea, Ioana; Sawhney, Kawal; Scott, Stewart; Hillman, Michael; Grindrod, Jamie; Johnson, Iain

    2015-12-01

    Accurate generation of small angles is of vital importance for calibrating angle-based metrology instruments used in a broad spectrum of industries including mechatronics, nano-positioning, and optic fabrication. We present a novel, piezo-driven, flexure device capable of reliably generating micro- and nanoradian angles. Unlike many such instruments, Diamond Light Source's nano-angle generator (Diamond-NANGO) does not rely on two separate actuators or rotation stages to provide coarse and fine motion. Instead, a single Physik Instrumente NEXLINE "PiezoWalk" actuator provides millimetres of travel with nanometre resolution. A cartwheel flexure efficiently converts displacement from the linear actuator into rotary motion with minimal parasitic errors. Rotation of the flexure is directly measured via a Magnescale "Laserscale" angle encoder. Closed-loop operation of the PiezoWalk actuator, using high-speed feedback from the angle encoder, ensures that the Diamond-NANGO's output drifts by only ∼0.3 nrad rms over ∼30 min. We show that the Diamond-NANGO can reliably move with unprecedented 1 nrad (∼57 ndeg) angular increments over a range of >7000 μrad. An autocollimator, interferometer, and capacitive displacement sensor are used to independently confirm the Diamond-NANGO's performance by simultaneously measuring the rotation of a reflective cube.

  7. Incremental planning to control a blackboard-based problem solver

    NASA Technical Reports Server (NTRS)

    Durfee, E. H.; Lesser, V. R.

    1987-01-01

    To control problem solving activity, a planner must resolve uncertainty about which specific long-term goals (solutions) to pursue and about which sequences of actions will best achieve those goals. A planner is described that abstracts the problem solving state to recognize possible competing and compatible solutions and to roughly predict the importance and expense of developing these solutions. With this information, the planner plans sequences of problem solving activities that most efficiently resolve its uncertainty about which of the possible solutions to work toward. The planner only details actions for the near future because the results of these actions will influence how (and whether) a plan should be pursued. As problem solving proceeds, the planner adds new details to the plan incrementally, and monitors and repairs the plan to insure it achieves its goals whenever possible. Through experiments, researchers illustrate how these new mechanisms significantly improve problem solving decisions and reduce overall computation. They briefly discuss current research directions, including how these mechanisms can improve a problem solver's real-time response and can enhance cooperation in a distributed problem solving network.

  8. [Effect of menstrual cycle on cardiorespiratory system during incremental exercise].

    PubMed

    Mesaki, N; Sasaki, J; Shoji, M; Iwasaki, H; Asano, K; Eda, M

    1986-01-01

    According to the results of questionnaires to college athletes, they believe the follicular phase is better than luteal phase for competitive sports. However, it is not clear whether there is significant difference in athletic performance between the two phases of the menstrual cycle. The effects of the menstrual cycle on the cardiorespiratory system were investigated in exercising women who are top players of basketball in Japan. They performed incremental exercise on a cycle ergometer. During the exercise, the ECG and heart rate (HR) were monitored. The expired air was sampled continuously and expiratory gas volume/minute (VE), oxygen uptake (VO2), carbon dioxide output (VCO2), gas exchange ratio(R) and respiratory rate (Resp. E.) were measured. Blood samples were collected to measure the blood lactic acid concentration during the exercise. HR in the luteal phase is higher than in the follicular phase at rest and throughout the exercise. VE, R and Resp. R. at rest and during exercise indicated a tendency to a higher level in the follicular phase. The blood lactic acid concentration during exercise in the follicular phase indicated a tendency to increase more rapidly than in luteal phase. However, no statistical differences in the cardiorespiratory system were detected when the follicular and luteal phase were compared. These results did not indicate conclusively in which phase it is better for athletic women to take part in competitive sports.

  9. Corona initiated from grounded objects under thunderstorm conditions and its influence on lightning attachment

    NASA Astrophysics Data System (ADS)

    Bazelyan, E. M.; Raizer, Yu P.; Aleksandrov, N. L.

    2008-05-01

    Lightning attachment to grounded structures due to the initiation of an upward connecting leader from them is considered taking into account the effect of corona space charge near the structures. It is shown that the corona space charge strongly affects the initiation and development of the connecting leader. Specific features of a non-stationary corona are analysed analytically and numerically for one-dimensional electrode geometries and for a grounded rod coronating in a slowly varying thundercloud electric field that can be enhanced by the charge of an approaching downward lightning leader. Initiation and development of an upward connecting leader or upward lightning from high ground objects are investigated. Prospects of using the effect of coronae to control downward lightning discharges are discussed.

  10. IUE and the search for a lukewarm corona. [of cooler stars

    NASA Technical Reports Server (NTRS)

    Pasachoff, J. M.; Linsky, J. L.; Haisch, B. M.; Boggess, A.

    1979-01-01

    The use of the International Ultraviolet Explorer (IUE) to search for stars having neither a hot corona nor a cool outer atmosphere, but a lukewarm corona is outlined. An interactive computer system permits extensive analysis of the data immediately after transmission to earth, allowing the results of one exposure to influence the taking of subsequent exposures. The observation program is illustrated for the star HR 1099, noting that observations were taken while previous spectra were being analyzed. Observations of many stars of spectral types G and K lead to the construction of a border region on the Hertzsprung-Russell diagram between stars with hot coronas and those with cool outer atmospheres. Stars lying near this border region were then observed, however none with lukewarm coronas were found. The interactive control facility in the satellite control room is considered an important factor in the efficient implementation of the search procedure.

  11. Transfer of electrical space charge from corona between ground and thundercloud: Measurements and modeling

    NASA Technical Reports Server (NTRS)

    Soula, Serge

    1994-01-01

    The evolution of the vertical electric field profile deduced from simultaneous field measurements at several levels below a thundercloud shows the development of a space charge layer at least up to 600 m. The average charge density in the whole layer from 0 m to 600 m can reach about 1 nC m(exp -3). The ions are generated at the ground by corona effect and the production rate is evaluated with a new method from the comparison of field evolutions at the ground and at altitude after a lightning flash. The modeling of the relevant processes shows tht ground corona accounts for the observed field evolutions and that the aerosol particles concentration has a very large effect on the evolution of corona ions. However, with a realistic value for this concentration a large amount of ground corona ions reach the level of 600 m.

  12. Carbohydrate-Based Nanocarriers Exhibiting Specific Cell Targeting with Minimum Influence from the Protein Corona.

    PubMed

    Kang, Biao; Okwieka, Patricia; Schöttler, Susanne; Winzen, Svenja; Langhanki, Jens; Mohr, Kristin; Opatz, Till; Mailänder, Volker; Landfester, Katharina; Wurm, Frederik R

    2015-06-15

    Whenever nanoparticles encounter biological fluids like blood, proteins adsorb on their surface and form a so-called protein corona. Although its importance is widely accepted, information on the influence of surface functionalization of nanocarriers on the protein corona is still sparse, especially concerning how the functionalization of PEGylated nanocarriers with targeting agents will affect protein corona formation and how the protein corona may in turn influence the targeting effect. Herein, hydroxyethyl starch nanocarriers (HES-NCs) were prepared, PEGylated, and modified on the outer PEG layer with mannose to target dendritic cells (DCs). Their interaction with human plasma was then studied. Low overall protein adsorption with a distinct protein pattern and high specific affinity for DC binding were observed, thus indicating an efficient combination of "stealth" and targeting behavior.

  13. Sterilisation of Hydroponic Culture Solution Contaminated by Fungi using an Atmospheric Pressure Corona Discharge

    NASA Astrophysics Data System (ADS)

    Mizukami, Kohji; Satoh, Kohki; Kanayama, Hiroshi; Itoh, Hidenori; Tagashira, Hiroaki; Shimozuma, Mitsuo; Okamoto, Hiroyuki; Takasaki, Satoko; Kinoshita, Muneshige

    The hydroponic culture solution contaminated by fungi is sterilised by a DC corona discharge, and the sterilisation characteristics are investigated in this work. A DC streamer corona discharge is generated at atmospheric pressure in air between needle clusters and a water bath containing contaminated solution by fungus such as Fusarium oxysporum f. sp. spinaciae or Fusarium sp.. It is found that the fungi are killed by the exposure of the corona discharge, and that the death rates of the fungi chiefly depend on the concentration of the hydroponic culture solutions. It is also found that the number densities of the fungi decrease exponentially with the energy expenditure of the corona discharge, and that damping coefficients of the fungi densities depend on the concentration of the hydroponic culture solutions. This suggests that the fungi are chiefly inactivated by electroporation.

  14. Guided corona generates wettability patterns that selectively direct cell attachment inside closed microchannels.

    PubMed

    Dixon, Angela; Takayama, Shuichi

    2010-10-01

    We present a method to create plasma mediated linear protein patterns along the lengths of simple one-inlet-one-outlet straight polydimethylsiloxane microchannels by biasing the delivery of corona discharge at the capillary openings. Pattern widths ranging from 500-1,000 microm were generated in 2 mm wide microchannels with lengths of 0.5, 1.0, or 1.5 cm. Corona-treated surfaces enabled the spatial alignment of C2C12 myoblasts to the adhesive protein-coated regions, facilitating myoblast differentiation into myotubes. Although limited in precision, this protein patterning technique offers the advantages of simplicity and low cost, making it attractive for educational and research environments that lack access to extensive microfabrication facilities. The results also provide a cautionary note to those using corona discharge to increase wettability of microchannels; the surface modification may not be uniform, even within single microchannels being treated depending on settings and positioning of the corona device tips.

  15. Effect of the protein corona on nanoparticles for modulating cytotoxicity and immunotoxicity

    PubMed Central

    Lee, Yeon Kyung; Choi, Eun-Ju; Webster, Thomas J; Kim, Sang-Hyun; Khang, Dongwoo

    2015-01-01

    Although the cytotoxicity of nanoparticles (NPs) is greatly influenced by their interactions with blood proteins, toxic effects resulting from blood interactions are often ignored in the development and use of nanostructured biomaterials for in vivo applications. Protein coronas created during the initial reaction with NPs can determine the subsequent immunological cascade, and protein coronas formed on NPs can either stimulate or mitigate the immune response. Along these lines, the understanding of NP-protein corona formation in terms of physiochemical surface properties of the NPs and NP interactions with the immune system components in blood is an essential step for evaluating NP toxicity for in vivo therapeutics. This article reviews the most recent developments in NP-based protein coronas through the modification of NP surface properties and discusses the associated immune responses. PMID:25565807

  16. Synthesis of CORONA 5 (Ti-4.5Al-5Mo-1.5Cr)

    NASA Astrophysics Data System (ADS)

    Froes, F. H.; Highberger, W. T.

    1980-05-01

    The synthesis of CORONA 5 (Ti-4.5Al-5Mo-1.5Cr) is described from the viewpoints of alloy chemistry and microstructure. Lenticular alpha is shown to maximize fracture resistance parameters, while a globular alpha optimizes hightemperature flow characteristics. The processing and application of CORONA 5 as forging, plate, sheet and powder metallurgy products are presented. The weldability of the alloy is described and potential use of the alloy for engine applications discussed. The improved mechanical property behavior over the "workhorse" Ti-6Al-4V alloy combined with cost-effective production should result in use of CORONA 5 in many applications. Future developments for CORONA 5 are suggested both in terms of further mechanical property optimization and in light of the economics of producing the alloy.

  17. Hi-C Observations of an Active Region Corona, and Investigation of the Underlying Magnetic Structure

    NASA Technical Reports Server (NTRS)

    Tiwari, S. K.; Alexander, C. E.; Winebarger, A.; Moore, R. L.

    2014-01-01

    The solar corona is much hotter (>=10(exp 6) K) than its surface (approx 6000 K), puzzling astrophysicists for several decades. Active region (AR) corona is again hotter than the quiet Sun (QS) corona by a factor of 4-10. The most widely accepted mechanism that could heat the active region corona is the energy release by current dissipation via reconnection of braided magnetic field structure, first proposed by E. N. Parker three decades ago. The first observational evidence for this mechanism has only recently been presented by Cirtain et al. by using High-resolution Coronal Imager (Hi-C) observations of an AR corona at a spatial resolution of 0.2 arcsec, which is required to resolve the coronal loops, and was not available before the rocket flight of Hi-C in July 2012. The Hi-C project is led by NASA/MSFC. In the case of the QS, work done by convection/granulation on the inter-granular feet of the coronal field lines translates into the heat observed in the corona. In the case of the AR, as here, there could be flux emergence, cancellation/submergence, or shear flows generating large stress and tension in coronal field loops which is released as heat in the corona. We are currently investigating the changes taking place in photospheric feet of the magnetic field involved with brightenings in the Hi-C AR corona. For this purpose, we are also using SDO/AIA data of +/- 2 hours around the 5 minutes Hi-C flight. In the present talk, I will first summarize some of the results of the Hi-C observations and then present some results from our recent analysis on what photospheric processes feed the magnetic energy that dissipates into heat in coronal loops.

  18. Charge Exchange and Ablation Rates of a Titanium Wire Plasma Corona

    SciTech Connect

    Terry, Robert E.

    2009-01-21

    Wire ablation rates are important features in any examination of precursors or transparent mode implosions of wire arrays. When ion temperatures in a Ti wire plasma corona exceed a few eV, the process of resonant charge exchange competes with elastic scattering. Ions pushed into the corona from an anode bias wire array can be expected to drive a fast neutral wind into the surrounding volume, while a cathode bias wire array would not show the strong neutral wind.

  19. Influence of electrostatic precipitator collecting plate spacing and corona power upon performance

    SciTech Connect

    Brummer, J.H.

    1983-01-01

    Results from the extensive electrostatic precipitator field test program from two plant sites are presented. The effects of collecting plate spacing design and the control of corona power on performance and particulate emission are evaluated. The test program evaluation includes a precipitator performance comparison between a nine inch and a twelve inch collecing plate spacing design and corona power optimization for rigid frame precipitator design.

  20. Shock Formation Height in the Solar Corona Estimated from SDO and Radio Observations

    NASA Technical Reports Server (NTRS)

    Gopalswamy, N.; Nitta, N.

    2011-01-01

    Wave transients at EUV wavelengths and type II radio bursts are good indicators of shock formation in the solar corona. We use recent EUV wave observations from SDO and combine them with metric type II radio data to estimate the height in the corona where the shocks form. We compare the results with those obtained from other methods. We also estimate the shock formation heights independently using white-light observations of coronal mass ejections that ultimately drive the shocks.