Sample records for emerging serpentine flux

  1. Nonlinear Force-Free Extrapolation of Emerging Flux with a Global Twist and Serpentine Fine Structures (United States)

    Valori, G.; Green, L. M.; Démoulin, P.; Vargas Domínguez, S.; van Driel-Gesztelyi, L.; Wallace, A.; Baker, D.; Fuhrmann, M.


    We study the flux emergence process in NOAA active region 11024, between 29 June and 7 July 2009, by means of multi-wavelength observations and nonlinear force-free extrapolation. The main aim is to extend previous investigations by combining, as much as possible, high spatial resolution observations to test our present understanding of small-scale (undulatory) flux emergence, whilst putting these small-scale events in the context of the global evolution of the active region. The combination of these techniques allows us to follow the whole process, from the first appearance of the bipolar axial field on the east limb, until the buoyancy instability could set in and raise the main body of the twisted flux tube through the photosphere, forming magnetic tongues and signatures of serpentine field, until the simplification of the magnetic structure into a main bipole by the time the active region reaches the west limb. At the crucial time of the main emergence phase high spatial resolution spectropolarimetric measurements of the photospheric field are employed to reconstruct the three-dimensional structure of the nonlinear force-free coronal field, which is then used to test the current understanding of flux emergence processes. In particular, knowledge of the coronal connectivity confirms the identity of the magnetic tongues as seen in their photospheric signatures, and it exemplifies how the twisted flux, which is emerging on small scales in the form of a sea-serpent, is subsequently rearranged by reconnection into the large-scale field of the active region. In this way, the multi-wavelength observations combined with a nonlinear force-free extrapolation provide a coherent picture of the emergence process of small-scale magnetic bipoles, which subsequently reconnect to form a large-scale structure in the corona.

  2. Clustering of Emerging Flux (United States)

    Ruzmaikin, A.


    Observations show that newly emerging flux tends to appear on the Solar surface at sites where there is flux already. This results in clustering of solar activity. Standard dynamo theories do not predict this effect.

  3. Flux Emergence (Theory

    Directory of Open Access Journals (Sweden)

    Mark C. M. Cheung


    Full Text Available Magnetic flux emergence from the solar convection zone into the overlying atmosphere is the driver of a diverse range of phenomena associated with solar activity. In this article, we introduce theoretical concepts central to the study of flux emergence and discuss how the inclusion of different physical effects (e.g., magnetic buoyancy, magnetoconvection, reconnection, magnetic twist, interaction with ambient field in models impact the evolution of the emerging field and plasma.

  4. Initiation of CMEs by Magnetic Flux Emergence

    Indian Academy of Sciences (India)

    Keywords. Sun: corona, coronal mass ejections; magnetic fields; magnetohydrodynamics; flux emergence. Abstract. The initiation of solar Coronal Mass Ejections (CMEs) is studied in the framework of numerical magnetohydrodynamics (MHD). The initial CME model includes a magnetic flux rope in spherical, axisymmetric ...

  5. 3D MHD Flux emergence experiments

    DEFF Research Database (Denmark)

    Hood, A.W.; Archontis, V.; Mactaggart, David


    This paper reviews some of the many 3D numerical experiments of the emergence of magnetic fields from the solar interior and the subsequent interaction with the pre-existing coronal magnetic field. The models described here are idealised, in the sense that the internal energy equation only involves...

  6. Emergence of Twisted Magnetic Flux Related Sigmoidal Brightening

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Astrophysics and Astronomy; Volume 21; Issue 3-4. Emergence of Twisted Magnetic Flux Related Sigmoidal Brightening. K. Sundara Raman K. B. Ramesh R. Selvendran P. S. M. Aleem K. M. Hiremath. Session V – Vector Magnetic Fields, Prominences, CMEs & Flares Volume 21 Issue 3-4 ...

  7. Initiation of CMEs by Magnetic Flux Emergence Govind Dubey , Bart ...

    Indian Academy of Sciences (India)

    magnetohydrodynamics—flux emergence. 1. Introduction. Coronal Mass Ejections (CMEs) play acrucial rolein space weather and a careful study of the origin, structure, and propagation characteristics of this violent phenomenon is essential for a deeper insight into space weather physics. The fast CMEs are important.

  8. Testing predictors of eruptivity using parametric flux emergence simulations

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    Guennou Chloé


    Full Text Available Solar flares and coronal mass ejections (CMEs are among the most energetic events in the solar system, impacting the near-Earth environment. Flare productivity is empirically known to be correlated with the size and complexity of active regions. Several indicators, based on magnetic field data from active regions, have been tested for flare forecasting in recent years. None of these indicators, or combinations thereof, have yet demonstrated an unambiguous eruption or flare criterion. Furthermore, numerical simulations have been only barely used to test the predictability of these parameters. In this context, we used the 3D parametric magnetohydrodynamic (MHD numerical simulations of the self-consistent formation of the flux emergence of a twisted flux tube, inducing the formation of stable and unstable magnetic flux ropes of Leake et al. (2013, 2014. We use these numerical simulations to investigate the eruptive signatures observable in various magnetic scalar parameters and provide highlights on data analysis processing. Time series of 2D photospheric-like magnetograms are used from parametric simulations of stable and unstable flux emergence, to compute a list of about 100 different indicators. This list includes parameters previously used for operational forecasting, physical parameters used for the first time, as well as new quantities specifically developed for this purpose. Our results indicate that only parameters measuring the total non-potentiality of active regions associated with magnetic inversion line properties, such as the Falconer parameters Lss, WLss, Lsg, and WLsg, as well as the new current integral WLsc and length Lsc parameters, present a significant ability to distinguish the eruptive cases of the model from the non-eruptive cases, possibly indicating that they are promising flare and eruption predictors. A preliminary study about the effect of noise on the detection of the eruptive signatures is also proposed.

  9. Solar magnetic fields - The generation of emerging flux (United States)

    Golub, L.; Rosner, R.; Vaiana, G. S.; Weiss, N. O.


    X-ray observations have provided information about magnetic fields on the sun, and the implications of these observations are discussed. The pattern of small-scale flux emergence is quite different from that of active regions. It is inferred that the small-scale fields originate fairly high in the convective zone, while the fields in active regions have a deeper origin. The small-scale turbulent fields are only loosely related to the fields that define the normal solar cycle. The way in which dynamo models must be modified in the light of these results is indicated.

  10. Homologous Circular-ribbon Flares Driven by Twisted Flux Emergence (United States)

    Xu, Z.; Yang, K.; Guo, Y.; Zhao, J.; Zhao, Z. J.; Kashapova, L.


    In this paper, we report two homologous circular-ribbon flares associated with two filament eruptions. They were well observed by the New Vacuum Solar Telescope and the Solar Dynamics Observatory on 2014 March 5. Prior to the flare, two small-scale filaments enclosed by a circular pre-flare brightening lie along the circular polarity inversion line around the parasitic polarity, which has shown a continuous rotation since its first appearance. Two filaments eventually erupt in sequence associated with two homologous circular-ribbon flares and display an apparent writhing signature. Supplemented by the nonlinear force-free field extrapolation and the magnetic field squashing factor investigation, the following are revealed. (1) This event involves the emergence of magnetic flux ropes into a pre-existing polarity area, which yields the formation of a 3D null-point topology in the corona. (2) Continuous input of the free energy in the form of a flux rope from beneath the photosphere may drive a breakout-type reconnection occurring high in the corona, supported by the pre-flare brightening. (3) This initiation reconnection could release the constraint on the flux rope and trigger the MHD instability to first make filament F1 lose equilibrium. The subsequent more violent magnetic reconnection with the overlying flux is driven during the filament rising. In return, the eruption of filament F2 is further facilitated by the reduction of the magnetic tension force above. These two processes form a positive feedback to each other to cause the energetic mass eruption and flare.

  11. Data Mining Solar X-Ray Flares Triggered by Emerging Magnetic Flux (United States)

    Loftus, Kaitlyn; Saar, Steven H.; Schanche, Nicole


    We investigate the association between emerging magnetic flux and solar X-ray flares to identify, and if possible quantify, distinguishing physical properties of flares triggered by flux emergence versus those triggered by other sources. Our study uses as its basis GOES-classified solar flares from March 2011 through June 2016 that have been identified by the Space Weather Prediction Center’s flare detection algorithm. The basic X-ray flare data is then enriched with data about related EUV-spectrum flares, emerging fluxes, active regions, eruptions, and sigmoids, which are all characterized by event-specific keywords, identified via SDO feature finding tools, and archived in the Heliophysics Events Knowledgebase (HEK). Using appropriate spatial and temporal parameters for each event type to determine association, we create a catalogue of solar events associated with each GOES-classified flare. After accounting for the primitive state of many of these event detection algorithms, we statistically analyze the compiled dataset to determine the effects of an emerging flux trigger on flare properties. A two-sample Kolmogorov-Smirnov test confirms with 99.9% confidence that flares triggered by emerging flux have a different peak flux distribution than non-emerging-flux-associated flares. We observe no linear or logarithmic correlations between flares’ and their associated emerging fluxes’ individual properties and find flares triggered by emerging flux are ~ 10% more likely to cause an eruption inside an active region while outside of an active region, the flare’s association with emerging flux has no effect on its likeliness to cause an eruption. We also compare the morphologies of the flares triggered by emerging flux and flares not via a superposed epoch analysis of lightcurves. Our results will be of interest for predicting flare behavior as a function of magnetic activity (where we can use enhanced rates of emerging flux as a proxy for heightened stellar

  12. Species adaptive strategies and leaf economic relationships across serpentine and non-serpentine habitats on Lesbos, eastern Mediterranean.

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    George C Adamidis

    Full Text Available Shifts in species' traits across contrasting environments have the potential to influence ecosystem functioning. Plant communities on unusually harsh soils may have unique responses to environmental change, through the mediating role of functional plant traits. We conducted a field study comparing eight functional leaf traits of seventeen common species located on both serpentine and non-serpentine environments on Lesbos Island, in the eastern Mediterranean. We focused on species' adaptive strategies across the two contrasting environments and investigated the effect of trait variation on the robustness of core 'leaf economic' relationships across local environmental variability. Our results showed that the same species followed a conservative strategy on serpentine substrates and an exploitative strategy on non-serpentine ones, consistent with the leaf economic spectrum predictions. Although considerable species-specific trait variability emerged, the single-trait responses across contrasting environments were generally consistent. However, multivariate-trait responses were diverse. Finally, we found that the strength of relationships between core 'leaf economic' traits altered across local environmental variability. Our results highlight the divergent trait evolution on serpentine and non-serpentine communities and reinforce other findings presenting species-specific responses to environmental variation.

  13. Serpentinization and Life: Motivations for Drilling the Atlantis Massif (United States)

    Frueh-Green, G. L.; Lang, S. Q.; Brazelton, W. J.; Schrenk, M. O.


    The Atlantis Massif, located at the intersection of the Atlantis transform fault and the Mid-Atlantic Ridge at 30°N, is one of the best-studied oceanic core complexes (OCCs) and is the target of IODP Expedition 357 late 2015. Drilling will address two exciting discoveries in ridge research: off-axis, serpentinite-hosted hydrothermal activity and carbonate precipitation, exemplified by the Lost City hydrothermal field, and the significance of tectono-magmatic processes in forming heterogeneous and variably serpentinized lithosphere as key components of slow spreading ridges. Serpentinization reactions at moderate- to low-temperatures result in alkaline fluids, characterized by elevated concentrations of abiotic hydrogen, methane and low molecular weight hydrocarbons, and which lead to precipitation of carbonate and brucite upon mixing with seawater. These highly reactive systems have major consequences for lithospheric cooling, global geochemical cycles, carbon sequestration and microbial activity. However, little is known about the nature and distribution of microbial communities in subsurface ultramafic environments and the potential for a hydrogen-based deep biosphere in areas of active serpentinization and fluid circulation. The continuous flux of reduced compounds provides abundant thermodynamic energy to drive chemolithoautotrophy, however, carbon availability may be limited in these high pH environments and represent a challenge for microbial growth. Here we review serpentinization processes as fundamental to understanding the evolution of oceanic lithosphere and discuss open questions related to the impact of serpentinization on the subsurface biosphere. Motivations for drilling the shallow subseafloor of the Atlantis Massif include: (1) exploring the extent and activity of the subsurface biosphere in young ultramafic and mafic seafloor; (2) quantifying the role of serpentinization in driving hydrothermal systems, in sustaining microbiological communities

  14. Biological Potential in Serpentinizing Systems (United States)

    Hoehler, Tori M.


    Generation of the microbial substrate hydrogen during serpentinization, the aqueous alteration of ultramafic rocks, has focused interest on the potential of serpentinizing systems to support biological communities or even the origin of life. However the process also generates considerable alkalinity, a challenge to life, and both pH and hydrogen concentrations vary widely across natural systems as a result of different host rock and fluid composition and differing physical and hydrogeologic conditions. Biological potential is expected to vary in concert. We examined the impact of such variability on the bioenergetics of an example metabolism, methanogenesis, using a cell-scale reactive transport model to compare rates of metabolic energy generation as a function of physicochemical environment. Potential rates vary over more than 5 orders of magnitude, including bioenergetically non-viable conditions, across the range of naturally occurring conditions. In parallel, we assayed rates of hydrogen metabolism in wells associated with the actively serpentinizing Coast Range Ophiolite, which includes conditions more alkaline and considerably less reducing than is typical of serpentinizing systems. Hydrogen metabolism is observed at pH approaching 12 but, consistent with the model predictions, biological methanogenesis is not observed.

  15. The Emergence of Kinked Flux Tubes as the Source of Delta-Spots on the Photosphere (United States)

    Knizhnik, Kalman; Linton, Mark; Norton, Aimee Ann


    It has been observationally well established that the magnetic configurations most favorable to producing energetic flaring events reside in so called delta-spots. These delta-spots are a subclass of sunspots, and are classified as sunspots which have umbrae (dark regions in the interior of sunspots) with opposite magnetic polarities that share a common penumbra. They are characterized by strong rotation and an extremely compact magnetic configuration, and are observed to follow an inverse-Hale law. It has been shown that over 90% of X-class flares that occurred during solar cycles 22 and 23 originated in delta-spots (Guo, Lin & Deng, 2014). Understanding the origin of delta-spots, therefore, is a crucial step towards the ultimate goal of space weather forecasting. In this work, we argue that delta-spots arise during the emergence of kinked flux tubes into the corona, and that their unique properties are due to the emergence of knots present in the kink mode of twisted flux tubes. We present numerical simulations that study the emergence of both kink-stable and unstable flux tubes into the solar corona, and demonstrate quantitatively that their photospheric signatures are dramatically different, with the latter flux tubes demonstrating strong coherent rotation and a very tight flux distribution on the photosphere. We show that the coronal magnetic field resulting from the emergence of a kinked flux tube contains significantly more free energy than the unkinked case, potentially leading to more energetic flares. We discuss the implications of our simulations for observations.

  16. Spectropolarimetric Evidence for a Siphon Flow along an Emerging Magnetic Flux Tube

    Energy Technology Data Exchange (ETDEWEB)

    Requerey, Iker S.; Cobo, B. Ruiz [Instituto de Astrofísica de Canarias, Vía Láctea s/n, E-38205 La Laguna, Tenerife (Spain); Iniesta, J. C. Del Toro; Suárez, D. Orozco [Instituto de Astrofísica de Andalucía (CSIC), Apdo. de Correos 3004, E-18080 Granada (Spain); Rodríguez, J. Blanco [Grupo de Astronomía y Ciencias del Espacio, Universidad de Valencia, E-46980 Paterna, Valencia (Spain); Solanki, S. K.; Barthol, P.; Gandorfer, A.; Gizon, L.; Hirzberger, J.; Riethmüller, T. L.; Noort, M. van [Max-Planck-Institut für Sonnensystemforschung, Justus-von-Liebig-Weg 3, D-37077 Göttingen (Germany); Schmidt, W. [Kiepenheuer-Institut für Sonnenphysik, Schöneckstr. 6, D-79104 Freiburg (Germany); Pillet, V. Martínez [National Solar Observatory, 3665 Discovery Drive, Boulder, CO 80303 (United States); Knölker, M., E-mail: [High Altitude Observatory, National Center for Atmospheric Research, P.O. Box 3000, Boulder, CO 80307-3000 (United States)


    We study the dynamics and topology of an emerging magnetic flux concentration using high spatial resolution spectropolarimetric data acquired with the Imaging Magnetograph eXperiment on board the sunrise balloon-borne solar observatory. We obtain the full vector magnetic field and the line of sight (LOS) velocity through inversions of the Fe i line at 525.02 nm with the SPINOR code. The derived vector magnetic field is used to trace magnetic field lines. Two magnetic flux concentrations with different polarities and LOS velocities are found to be connected by a group of arch-shaped magnetic field lines. The positive polarity footpoint is weaker (1100 G) and displays an upflow, while the negative polarity footpoint is stronger (2200 G) and shows a downflow. This configuration is naturally interpreted as a siphon flow along an arched magnetic flux tube.

  17. Mantle wedge serpentinization effects on slab dips

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    Eh Tan


    Full Text Available The mechanical coupling between a subducting slab and the overlying mantle wedge is an important factor in controlling the subduction dip angle and the flow in mantel wedge. This paper investigates the role of the amount of mantle serpentinization on the subduction zone evolution. With numerical thermos-mechanical models with elasto-visco-plastic rheology, we vary the thickness and depth extent of mantle serpentinization in the mantle wedge to control the degree of coupling between the slab and mantle wedge. A thin serpentinized mantle layer is required for stable subduction. For models with stable subduction, we find that the slab dip is affected by the down-dip extent and the mantle serpentinization thickness. A critical down-dip extent exists in mantle serpentinization, determined by the thickness of the overriding lithosphere. If the down-dip extent does not exceed the critical depth, the slab is partially coupled to the overriding lithosphere and has a constant dip angle regardless of the mantle serpentinization thickness. However, if the down-dip extent exceeds the critical depth, the slab and the base of the overriding lithosphere would be separated and decoupled by a thick layer of serpentinized peridotite. This allows further slab bending and results in steeper slab dip. Increasing mantle serpentinization thickness will also result in larger slab dip. We also find that with weak mantle wedge, there is no material flowing from the asthenosphere into the serpentinized mantle wedge. All of these results indicate that serpentinization is an important ingredient when studying the subduction dynamics in the mantle wedge.

  18. Design and motion planning for serpentine robots (United States)

    Choset, Howie M.; Luntz, Jonathan E.; Shammas, Ellie; Rached, Tarek; Hull, Douglas; Dent, Christina C.


    Serpentine robots offer advances over traditional mobile robots and robot arms because they have enhanced flexibility and reachability, especially in convoluted environments. These mechanisms are especially well suited for search and rescue operations where making contact with surviving victims trapped in a collapsed building is essential. The same flexibility that makes serpentine robots incredibly useful also makes them difficult to design and control. This paper will describe the current status of serpentine robot design and path planning underway in our research group and point towards future directions of research.

  19. Rare and Endangered Geophyte Plant Species in Serpentine of Kosovo


    Naim Berisha; Fadil Millaku; Elez Krasniqi; Bekim Gashi


    Our study documents information on rarity, geographical distribution, taxonomy and conservation status of 11 geophyte species in serpentine soils of Kosovo, already included in the Red Book of Vascular Flora of Kosovo. Kosovo’s serpentine vegetation represents a diversity that yet has not been sufficiently explored. Large serpentine complexes are found in the northern Kosovo but also southern part of the country is rich in serpentines, therefore in endemics. Serpentine rocks and soils are cha...

  20. Flux

    DEFF Research Database (Denmark)

    Ravn, Ib

    Med udgangspunkt i kompleksistetsforskning og studiet af selvorganiserende systemer beskriver lb Ravn den fysiske og biologiske evolution og menneskets udvikling. Han fortolker begreber som kultur, sprog, frihed, værdier, mening, smerte og det ondes problem i lyset af en procesbaseret ontologi...... kanalisering af den flux eller energi, der strømmer igennem os og giver sig til kende i vore daglige aktiviteter. Skal vores tanker, handlinger, arbejde, samvær og politiske liv organiseres efter stramme og faste regelsæt, uden slinger i valsen? Eller skal de tværtimod forløbe ganske uhindret af regler og bånd...

  1. Modelling the Initiation of Coronal Mass Ejections by Magnetic Flux Emergence (United States)

    Zuccarello, F. P.; Soenen, A.; Poedts, S.


    The possible role of magnetic flux emergence as triggering mechanism for the initiation of Coronal Mass Ejections (CMEs) is studied in the framework of the ideal magnetohydrodynamics (MHD) model. The full MHD equations are solved numerically on a spherical, axisymmetric (2.5D) domain. All simulations are performed with a modified version of the Versatile Advection Code (VAC) (Toth 1996). The magnetic field of the solution is maintained divergence-free at machine precision by exploiting an approach similar to that of Balsara and Spicer (1999): instead of storing the magnetic field components on a staggered mesh, we use the vector potential components in the nodes. In order to get satisfactorily solar wind properties, the Manchester et al. (2004) source term is implemented in the energy equation and gravity is taken into account as well in the model. Finally, a magnetic vector potential is superimposed at the inlet boundary of the Parker wind solution so that, when the steady state is reached, the Antiochos et al. (1999) triple arcade 'break out' magnetic field configuration (symmetric with respect to the equator) of a helmet streamers is obtained. When the steady state has been reached, we impose a magnetic flux emergence at the inlet boundary that is linearly growing in time during a time interval of ? t = 24 hours. After this time the vector potential at the solar base is again fixed. Due to the magnetic flux emergence at the solar base, extra radial magnetic field, is built up near the neutral line of the central arcade that expands outward. This generates an extra upward magnetic pressure force. As a consequence, the central flux system expands outward. Also the overlying field expands and, therefore, the downward magnetic tension increases. As a result, the X-point is flattened. When the distance between the central expanding arcade field and the overlying streamer field is of the order of the grid resolution, the (numerical) reconnection between these fields

  2. Borrowed alleles and convergence in serpentine adaptation. (United States)

    Arnold, Brian J; Lahner, Brett; DaCosta, Jeffrey M; Weisman, Caroline M; Hollister, Jesse D; Salt, David E; Bomblies, Kirsten; Yant, Levi


    Serpentine barrens represent extreme hazards for plant colonists. These sites are characterized by high porosity leading to drought, lack of essential mineral nutrients, and phytotoxic levels of metals. Nevertheless, nature forged populations adapted to these challenges. Here, we use a population-based evolutionary genomic approach coupled with elemental profiling to assess how autotetraploid Arabidopsis arenosa adapted to a multichallenge serpentine habitat in the Austrian Alps. We first demonstrate that serpentine-adapted plants exhibit dramatically altered elemental accumulation levels in common conditions, and then resequence 24 autotetraploid individuals from three populations to perform a genome scan. We find evidence for highly localized selective sweeps that point to a polygenic, multitrait basis for serpentine adaptation. Comparing our results to a previous study of independent serpentine colonizations in the closely related diploid Arabidopsis lyrata in the United Kingdom and United States, we find the highest levels of differentiation in 11 of the same loci, providing candidate alleles for mediating convergent evolution. This overlap between independent colonizations in different species suggests that a limited number of evolutionary strategies are suited to overcome the multiple challenges of serpentine adaptation. Interestingly, we detect footprints of selection in A. arenosa in the context of substantial gene flow from nearby off-serpentine populations of A. arenosa, as well as from A. lyrata In several cases, quantitative tests of introgression indicate that some alleles exhibiting strong selective sweep signatures appear to have been introgressed from A. lyrata This finding suggests that migrant alleles may have facilitated adaptation of A. arenosa to this multihazard environment.

  3. Recurrent CME-like Eruptions in Emerging Flux Regions. I. On the Mechanism of Eruptions (United States)

    Syntelis, P.; Archontis, V.; Tsinganos, K.


    We report on three-dimensional (3D) magnetohydrodynamic (MHD) simulations of recurrent eruptions in emerging flux regions. We find that reconnection of sheared field lines, along the polarity inversion line of an emerging bipolar region, leads to the formation of a new magnetic structure, which adopts the shape of a magnetic flux rope (FR) during its rising motion. Initially, the FR undergoes a slow-rise phase and, eventually, it experiences a fast-rise phase and ejective eruption toward the outer solar atmosphere. In total, four eruptions occur during the evolution of the system. For the first eruption, our analysis indicates that the torus instability initiates the eruption and that tether-cutting reconnection of the field lines, which envelop the FR, triggers the rapid acceleration of the eruptive field. For the following eruptions, we conjecture that it is the interplay between tether-cutting reconnection and torus instability that causes the onset of the various phases. We show the 3D shape of the erupting fields, focusing more on how magnetic field lines reconnect during the eruptions. We find that when the envelope field lines reconnect mainly with themselves, hot and dense plasma is transferred closer to the core of the erupting FR. The same area appears to be cooler and less dense when the envelope field lines reconnect with neighboring sheared field lines. The plasma density and temperature distribution, together with the rising speeds, energies, and size of the erupting fields, indicate that they may account for small-scale (mini) coronal mass ejections.

  4. Serpentine Locomotion Articulated Chain: ANA II

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    A. M. Cardona


    Full Text Available When humanity faces challenges in solving problems beyond their technical resources, and has no foundation to solve a problem, engineering must search for an answer developing new concepts and innovative frameworks to excel these limitations and travel beyond our capabilities. This project “Serpentine locomotion articulated chain: ANA II” is a self-contained robot built to evaluate the behavior of the platform being capable of serpentine movements, in a modular chain mechanical design, based on a master/slave architecture.

  5. Development and modeling of a flat plate serpentine reactor for photocatalytic degradation of 17-ethinylestradiol. (United States)

    Wang, Dawei; Li, Yi; Zhang, Wenlong; Wang, Qing; Wang, Peifang; Wang, Chao


    A flat plate serpentine reactor modified from ultraviolet disinfection pool in municipal wastewater treatment plants was developed for the removal of 17-ethinylestradiol (EE2) for the first time. The photocatalytic degradation performance of EE2 was investigated in this serpentine reactor under different conditions such as inlet concentrations, loaded catalyst concentrations, incident radiations fluxes, and flow velocities. More than 98% of EE2 was removed under certain conditions within 120 min. An integrated model including a six-flux adsorption-scattering model and a modified flow diffusion model was established to investigate the effect of radiation field and flow velocities, respectively. A satisfactory agreement was observed between the model simulation and experimental results, showing a potential for design and scale-up of photocatalytic reactor for wastewater treatment.

  6. Serpentinization and fluids in the forearc mantle (United States)

    Reynard, B.


    In the forearc region, aqueous fluids are released from the subducting slab, and tend to rise vertically unless they meet permeability barriers such as the deformed plate interface or the Moho of the overriding plate. Above the subducting plate, intense reactions between dehydration fluids from the subducting slab and ultramafic rocks result in extensive serpentinization in the forearc mantle wedge. The plate interface is mechanically decoupled, most likely because serpentines are low strength material, isolating the forearc mantle wedge from convection. Geophysical observations are unique probes to the interactions between fluids and rocks in the forearc mantle, and experimental constrains on rock properties are used to infer fluid migration and fluid/rock reactions from geophysical data. Seismic velocities reveal high degree of serpentinization of the forearc mantle in hot subduction zones, and little serpentinization in the coldest subduction zones because the warmer the subduction zone, the higher the amount of water released by dehydration of the hydrothermally altered oceanic lithosphere. Interpretation of seismic data from petrophysical constrain is limited by complex effects due to anisotropy that need to be assessed both in the analysis and interpretation of seismic data. Electrical conductivity of dry peridotites and serpentinites is similar, and high conductivities are found to be diagnostic of increasing fluid content, fluid salinity. Conductivities in the forearc increase with the temperature of the subduction. A notable exception is the forearc mantle of Northern Cascadia, the hottest subduction zone where extensive serpentinization was first demonstrated, that shows only modest electrical conductivity. Detailed electrical conductivity profiles suggest fluid content and chemistry may vary not only with the thermal state of the subduction zone but also with time through variations of fluid salinity. High-Cl fluids produced by serpentinization can mix

  7. Fate factors and emission flux estimates for emerging contaminants in surface waters

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    Hoa T. Trinh


    Full Text Available Pharmaceuticals, personal care products, hormones, and wastewater products are emerging environmental concerns for manifold reasons, including the potential of some compounds found in these products for endocrine disruption at a very low chronic exposure level. The environmental occurrences and sources of these contaminants in the water, soil, sediment and biota in European nations and the United States are well documented. This work reports a screening-level emission and fate assessment of thirty compounds, listed in the National Reconnaissance of the United States Geological Survey (USGS, 1999–2000 as the most frequently detected organic wastewater contaminants in U.S. streams and rivers. Estimations of the surface water fate factors were based on Level II and Level III multimedia fugacity models for a 1000 km2 model environment, the size of a typical county in the eastern United States. The compounds are categorized into three groups based upon the sensitivity of their predicted surface water fate factors to uncertainties in their physicochemical property values and the landscape parameters. The environmental fate factors, mass distributions, and loss pathways of all of the compounds are strongly affected by their assumed modes of entry into the environment. It is observed that for thirteen of the thirty organic wastewater contaminants most commonly detected in surface waters, conventional treatment strategies may be ineffective for their removal from wastewater effluents. The surface water fate factors predicted by the fugacity models were used in conjunction with the surface water concentrations measured in the USGS reconnaissance to obtain emission flux estimates for the compounds into U.S. streams and rivers. These include estimated fluxes of 6.8 × 10−5 to 0.30 kg/h km2 for the biomarker coprostanol; 1.7 × 10−5 to 6.5 × 10−5 kg/h km2 for the insect repellent N,N-diethyltoluamide; and 4.3 × 10−6 to 3.1 × 10−5 kg/h km2 for

  8. Effect of water activity on rates of serpentinization of olivine (United States)

    Lamadrid, Hector M.; Rimstidt, J. Donald; Schwarzenbach, Esther M.; Klein, Frieder; Ulrich, Sarah; Dolocan, Andrei; Bodnar, Robert J.


    The hydrothermal alteration of mantle rocks (referred to as serpentinization) occurs in submarine environments extending from mid-ocean ridges to subduction zones. Serpentinization affects the physical and chemical properties of oceanic lithosphere, represents one of the major mechanisms driving mass exchange between the mantle and the Earth's surface, and is central to current origin of life hypotheses as well as the search for microbial life on the icy moons of Jupiter and Saturn. In spite of increasing interest in the serpentinization process by researchers in diverse fields, the rates of serpentinization and the controlling factors are poorly understood. Here we use a novel in situ experimental method involving olivine micro-reactors and show that the rate of serpentinization is strongly controlled by the salinity (water activity) of the reacting fluid and demonstrate that the rate of serpentinization of olivine slows down as salinity increases and H2O activity decreases.

  9. Exploration of serpentine seamount, South Chamorro seamount (United States)

    Miyazaki, J.; Morono, Y.; Hirayama, H.; Inagaki, F.; Wheat, C. G.; Takai, K.


    Serpentinization and the following Fisher-Tropsch-type synthesis produce hydrogen and hydrocarbons. They become electron donors for microbes, and therefore it is believed that there are deep subseafloor microbial ecosystems supported by serpentinization. We have sought and elucidate the microbial ecosystem. South Chamorro Seamount is the one of the deep-sea serpentine mud volcanoes located in Mariana forearc (Fryer et al., 2006). These seamounts are formed by subducting Pacific plate under Mariana plate (Wheat et al., 2010). In this subduction process, the mantle in the Mariana plate on the fault was serpenrinized and the produced crustal fluid and muds were upwelling to the seafloor. South Chamorro Seamount has a big advantage to seek microbial ecosystems supported by serpentinization because there is borehole 1200c conducted by ODP#195 in 2001. Therefore we can access the deep subseafloor through the CORK observatory deployed on borehole 1200c. From the top of the CORK, the crustal fluid whose pH shows 12.3 was discharged. And also on the top of the CORK, brucites which was formed by mixing with seawater were also observed. Our first attempt is detection of microbes from this discharged crustal fluid. The number of cells is only 440 to 660 cells/mL, which indicated that two orders lower than that in seawater. But the analysis of microbial community structure showed that the major dominants are aerobic methanotrophs suggesting that discharged fluids were contamination with seawater. Therefore we have to sample directly from the depths of the borehole. To overcome this difficulty, we have developed a downhole sampling tool, Kandata system. This system is operated by only ROV and enables to directly sample crustal fluid and microbes and seal up them in the borehole. Therefore we can obtain deep crustal water and microbes without seawater contamination. In this February cruise we rolled down water sampler to 170 m below seafloor and sample water at this depth. And

  10. Simulations of Magnetic Flux Emergence in Cool, Low-Mass Stars: Toward Linking Dynamo Action with Starspots (United States)

    Weber, Maria Ann; Browning, Matthew; Nelson, Nicholas


    Starspots are windows into a star’s internal dynamo mechanism. However, the manner by which the dynamo-generated magnetic field traverses the stellar interior to emerge at the surface is not especially well understood. Establishing the details of magnetic flux emergence plays a key role in deciphering stellar dynamos and observed starspot properties. In the solar context, insight into this process has been obtained by assuming the magnetism giving rise to sunspots consists partly of idealized thin flux tubes (TFTs). Here, we present three sets of TFT simulations in rotating spherical shells of convection: one representative of the Sun, the second of a solar-like rapid rotator, and the third of a fully convective M dwarf. Our solar simulations reproduce sunspot observables such as low-latitude emergence, tilting action toward the equator following the Joy’s Law trend, and a phenomenon akin to active longitudes. Further, we compare the evolution of rising flux tubes in our (computationally inexpensive) TFT simulations to buoyant magnetic structures that arise naturally in a unique global simulation of a rapidly rotating Sun. We comment on the role of rapid rotation, the Coriolis force, and external torques imparted by the surrounding convection in establishing the trajectories of the flux tubes across the convection zone. In our fully convective M dwarf simulations, the expected starspot latitudes deviate from the solar trend, favoring significantly poleward latitudes unless the differential rotation is sufficiently prograde or the magnetic field is strongly super-equipartition. Together our work provides a link between dynamo-generated magnetic fields, turbulent convection, and observations of starspots along the lower main sequence.

  11. Subarctic physicochemical weathering of serpentinized peridotite (United States)

    Ulven, O. I.; Beinlich, A.; Hövelmann, J.; Austrheim, H.; Jamtveit, B.


    Frost weathering is effective in arctic and subarctic climate zones where chemical reactions are limited by the reduced availability of liquid water and the prevailing low temperature. However, small scale mineral dissolution reactions are nevertheless important for the generation of porosity by allowing infiltration of surface water with subsequent fracturing due to growth of ice and carbonate minerals. Here we combine textural and mineralogical observations in natural samples of partly serpentinized ultramafic rocks with a discrete element model describing the fracture mechanics of a solid when subject to pressure from the growth of ice and carbonate minerals in surface-near fractures. The mechanical model is coupled with a reaction-diffusion model that describes an initial stage of brucite dissolution as observed during weathering of serpentinized harzburgites and dunites from the Feragen Ultramafic Body (FUB), SE-Norway. Olivine and serpentine are effectively inert at relevant conditions and time scales, whereas brucite dissolution produces well-defined cm to dm thick weathering rinds with elevated porosity that allows influx of water. Brucite dissolution also increases the water saturation state with respect to hydrous Mg carbonate minerals, which are commonly found as infill in fractures in the fresh rock. This suggests that fracture propagation is at least partly driven by carbonate precipitation. Dissolution of secondary carbonate minerals during favorable climatic conditions provides open space available for ice crystallization that drives fracturing during winter. Our model reproduces the observed cm-scale meandering fractures that propagate into the fresh part of the rock, as well as dm-scale fractures that initiate the breakup of larger domains. Rock disintegration increases the reactive surface area and hence the rate of chemical weathering, enhances transport of dissolved and particulate matter in the weathering fluid, and facilitates CO2 uptake by

  12. The serpentine mitral valve and cerebral embolism

    Directory of Open Access Journals (Sweden)

    Ker James


    Full Text Available Abstract Valvular strands, well-delineated filiform masses, attached to cardiac valve edges are associated with cerebral embolism and stroke. Strokes, caused by emboli from valvular strands, tend to occur among younger persons. In this case report a valvular strand, giving a peculiar serpentine appearance to the mitral valve is described. This mitral valvular strand was the only explanation for an episode of cerebral embolism, presenting with a transient right sided hemiparesis. It is proposed that a randomized study involving combined treatment with aspirin and clopidogrel is warranted in young patients with valvular strands, presenting with a first episode of cerebral embolism.

  13. Growing up green on serpentine soils: Biogeochemistry of serpentine vegetation in the Central Coast Range of California (United States)

    Oze, C.; Skinner, C.; Schroth, A.W.; Coleman, R.G.


    Serpentine soils derived from the weathering of ultramafic rocks and their metamorphic derivatives (serpentinites) are chemically prohibitive for vegetative growth. Evaluating how serpentine vegetation is able to persist under these chemical conditions is difficult to ascertain due to the numerous factors (climate, relief, time, water availability, etc.) controlling and affecting plant growth. Here, the uptake, incorporation, and distribution of a wide variety of elements into the biomass of serpentine vegetation has been investigated relative to vegetation growing on an adjacent chert-derived soil. Soil pH, electrical conductivity, organic C, total N, soil extractable elements, total soil elemental compositions and plant digestions in conjunction with spider diagrams are utilized to determine the chemical relationships of these soil and plant systems. Plant available Mg and Ca in serpentine soils exceed values assessed in chert soils. Magnesium is nearly 3 times more abundant than Ca in the serpentine soils; however, the serpentine soils are not Ca deficient with Ca concentrations as high as 2235 mg kg-1. Calcium to Mg ratios (Ca:Mg) in both serpentine and chert vegetation are greater than one in both below and above ground tissues. Soil and plant chemistry analyses support that Ca is not a limiting factor for plant growth and that serpentine vegetation is actively moderating Mg uptake as well as tolerating elevated concentrations of bioavailable Mg. Additionally, results demonstrate that serpentine vegetation suppresses the uptake of Fe, Cr, Ni, Mn and Co into its biomass. The suppressed uptake of these metals mainly occurs in the plants' roots as evident by the comparatively lower metal concentrations present in above ground tissues (twigs, leaves and shoots). This research supports earlier studies that have suggested that ion uptake discrimination and ion suppression in the roots are major mechanisms for serpentine vegetation to tolerate the chemistry of

  14. Emergence flux declines disproportionately to larval density along a stream metals gradient (United States)

    Schmidt, Travis S.; Kraus, Johanna M.; Walters, David M.; Wanty, Richard B.


    Effects of contaminants on adult aquatic insect emergence are less well understood than effects on insect larvae. We compared responses of larval density and adult emergence along a metal contamination gradient. Nonlinear threshold responses were generally observed for larvae and emergers. Larval densities decreased significantly at low metal concentrations but precipitously at concentrations of metal mixtures above aquatic life criteria (Cumulative Criterion Accumulation Ratio (CCAR) ≥ 1). In contrast, adult emergence declined precipitously at low metal concentrations (CCAR ≤ 1), followed by a modest decline above this threshold. Adult emergence was a more sensitive indicator of the effect of low metals concentrations on aquatic insect communities compared to larvae, presumably because emergence is limited by a combination of larval survival and other factors limiting successful emergence. Thus effects of exposure to larvae are not manifest until later in life (during metamorphosis and emergence). This loss in emergence reduces prey subsidies to riparian communities at concentrations considered safe for aquatic life. Our results also challenge the widely held assumption that adult emergence is a constant proportion of larval densities in all streams.

  15. Serpentine locomotion through elastic energy release (United States)

    Movchan, N. V.


    A model for serpentine locomotion is derived from a novel perspective based on concepts from configurational mechanics. The motion is realized through the release of the elastic energy of a deformable rod, sliding inside a frictionless channel, which represents a snake moving against lateral restraints. A new formulation is presented, correcting previous results and including situations never analysed so far, as in the cases when the serpent's body lies only partially inside the restraining channel or when the body has a muscle relaxation localized in a small zone. Micromechanical considerations show that propulsion is the result of reactions tangential to the frictionless constraint and acting on the snake's body, a counter-intuitive feature in mechanics. It is also experimentally demonstrated that the propulsive force driving serpentine motion can be directly measured on a designed apparatus in which flexible bars sweep a frictionless channel. Experiments fully confirm the theoretical modelling, so that the presented results open the way to exploration of effects, such as variability in the bending stiffness or channel geometry or friction, on the propulsive force of snake models made up of elastic rods. PMID:28566512

  16. Is it worth hyperaccumulating Ni on non-serpentine soils? Decomposition dynamics of mixed-species litters containing hyperaccumulated Ni across serpentine and non-serpentine environments. (United States)

    Adamidis, George C; Kazakou, Elena; Aloupi, Maria; Dimitrakopoulos, Panayiotis G


    Nickel (Ni)-hyperaccumulating species produce high-Ni litters and may potentially influence important ecosystem processes such as decomposition. Although litters resembling the natural community conditions are essential in order to predict decomposition dynamics, decomposition of mixed-species litters containing hyperaccumulated Ni has never been studied. This study aims to test the effect of different litter mixtures containing hyperaccumulated Ni on decomposition and Ni release across serpentine and non-serpentine soils. Three different litter mixtures were prepared based on the relative abundance of the dominant species in three serpentine soils in the island of Lesbos, Greece where the Ni-hyperaccumulator Alyssum lesbiacum is present. Each litter mixture decomposed on its original serpentine habitat and on an adjacent non-serpentine habitat, in order to investigate whether the decomposition rates differ across the contrasted soils. In order to make comparisons across litter mixtures and to investigate whether additive or non-additive patterns of mass loss occur, a control non-serpentine site was used. Mass loss and Ni release were measured after 90, 180 and 270 d of field exposure. The decomposition rates and Ni release had higher values on serpentine soils after all periods of field exposure. The recorded rapid release of hyperaccumulated Ni is positively related to the initial litter Ni concentration. No differences were found in the decomposition of the three different litter mixtures at the control non-serpentine site, while their patterns of mass loss were additive. Our results: (1) demonstrate the rapid decomposition of litters containing hyperaccumulated Ni on serpentine soils, indicating the presence of metal-tolerant decomposers; and (2) imply the selective decomposition of low-Ni parts of litters by the decomposers on non-serpentine soils. This study provides support for the elemental allelopathy hypothesis of hyperaccumulation, presenting the

  17. Interactions Between Serpentinization, Hydrothermal Activity and Microbial Community at the Lost City Hydrothermal Field (United States)

    Delacour, A.; Frueh-Green, G. L.; Bernasconi, S. M.; Schaeffer, P.; Frank, M.; Gutjahr, M.; Kelley, D. S.


    Seafloor investigations of slow- and ultraslow-spreading ridges have reported many occurrences of exposed mantle peridotites and gabbroic rocks on the ocean floor. Along the Mid-Atlantic Ridge, these uplifted portions of oceanic crust host high-temperature black smoker-type hydrothermal systems (e.g., Rainbow, Logatchev, Saldanha), and the more distinct low-temperature Lost City Hydrothermal Field (LCHF). Built on a southern terrace of the Atlantis Massif, the LCHF is composed of carbonate-brucite chimneys that vent alkaline and low-temperature (40-90°C) hydrothermal fluids. These fluids are related to serpentinization of mantle peridotites, which together with minor gabbroic intrusions form the basement of the LCHF. Long-lived hydrothermal activity at Lost City led to extensive seawater-rock interaction in the basement rocks, as indicated by seawater-like Sr- and mantle to unradiogenic Nd-isotope compositions of the serpentinites. These high fluid fluxes in the southern part of the massif influenced the conditions of serpentinization and have obliterated the early chemical signatures in the serpentinites, especially those of carbon and sulfur. Compared to reducing conditions commonly formed during the first stages of serpentinization, serpentinization at Lost City is characterized by relatively oxidizing conditions resulting in a predominance of magnetite, the mobilization/dissolution and oxidation of igneous sulfides to secondary pyrite, and the incorporation of seawater sulfate, all leading to high bulk-rock S-isotope compositions. The Lost City hydrothermal fluids contain high concentrations in methane, hydrogen, and low-molecular weight hydrocarbons considered as being produced abiotically. In contrast, organic compounds in the serpentinites are dominated by the occurrences of isoprenoids (pristane, phytane, and squalane), polycyclic compounds (hopanes and steranes), and higher abundances of C16 to C20 n-alkanes indicative of a marine organic input. We

  18. Risk estimation and annual fluxes of emerging contaminants from a Scottish priority catchment to the estuary and North Sea. (United States)

    Zhang, Zulin; Lebleu, Melanie; Osprey, Mark; Kerr, Christine; Courtot, Estelle


    Emerging contaminants (ECs) such as endocrine-disrupting chemicals (EDCs) and pharmaceuticals and personal care products (PPCPs) attracted global concern during the last decades due to their potential adverse effects on humans and ecosystems. This work is the first study to assess the spatiotemporal changes, annual fluxes and ecological risk of ECs (4 EDCs and 6 PPCPs) by different monitoring strategies (spot and passive sampling) over 12 months in a Scottish priority catchment (River Ugie, Scotland, 335 km2). Overall, the total concentration in water ranged from risk assessment showed that bisphenol A posed the highest risks with 21.5% of the spot samples, resulting in a risk quotient >1. This suggests that mitigation measures might need to be taken to reduce the input of emerging contaminants into the river and its adjacent estuary and sea.

  19. Rare and Endangered Geophyte Plant Species in Serpentine of Kosovo

    Directory of Open Access Journals (Sweden)

    Naim Berisha


    Full Text Available Our study documents information on rarity, geographical distribution, taxonomy and conservation status of 11 geophyte species in serpentine soils of Kosovo, already included in the Red Book of Vascular Flora of Kosovo. Kosovo’s serpentine vegetation represents a diversity that yet has not been sufficiently explored. Large serpentine complexes are found in the northern Kosovo but also southern part of the country is rich in serpentines, therefore in endemics. Serpentine rocks and soils are characterized by low level of principal plant nutrients (N, P, K, Ca and exceptionally high levels of Mg and Fe. Serpentines play particular importance for flora of the country due to their richness in endemic plant species. The following 11 plant species have been studied: Aristolochia merxmuelleri, Colchicum hungaricum, Crocus flavus, Crocus kosaninii, Epimedium alpinum, Gentiana punctata, Gladiolus illyricus, Lilium albanicum, Paeonia peregrina, Tulipa gesneriana and Tulipa kosovarica. Five out of eleven studied geophytes fall within Critically Endangered IUCN based threat category and five out of eleven are local endemics. Aristolochia merxmuelleri and Tulipa kosovarica are steno-endemic plant species that are found exclusively in serpentine soils. Information in our database should prove to be valuable to efforts in ecology, floristics, biosystematics, conservation and land management.

  20. Thermal activation of serpentine for adsorption of cadmium

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Chun-Yan [College of Land and Environment, Shenyang Agricultural University, Shenyang (China); College of Chemistry, Chemical Engineering and Food Safety, Bohai University, Jinzhou (China); Liang, Cheng-Hua, E-mail: [College of Land and Environment, Shenyang Agricultural University, Shenyang (China); Yin, Yan [Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang (China); Du, Li-Yu [College of Land and Environment, Shenyang Agricultural University, Shenyang (China)


    Highlights: • Thermal activated serpentine was prepared by changing heated temperature. • Thermal activated serpentine exhibited excellent adsorption behavior for cadmium. • The adsorption mechanisms could be explained as formation of CdCO{sub 3} and Cd(OH){sub 2}. • The adsorption obeyed Langmuir model and pseudo second order kinetics model. - Abstract: Thermal activated serpentine with high adsorption capacity for heavy metals was prepared. The batch experiment studies were conducted to evaluate the adsorption performance of Cd{sup 2+} in aqueous solution using thermal activated serpentine as adsorbent. These samples before and after adsorption were characterized by XRD, FT-IR, SEM, XPS, and N{sub 2} adsorption-desorption at low temperature. It was found that serpentine with layered structure transformed to forsterite with amorphous structure after thermal treatment at over 700 °C, while the surface area of the samples was increased with activated temperature and the serpentine activated at 700 °C (S-700) presented the largest surface area. The pH of solution after adsorption was increased in different degrees due to hydrolysis of MgO in serpentine, resulting in enhancing adsorption of Cd{sup 2+}. The S-700 exhibited the maximum equilibrium adsorption capacity (15.21 mg/g), which was 2 times more than pristine serpentine. Langmuir isotherm was proved to describe the equilibrium adsorption data better than Freundlich isotherm and pseudo second order kinetics model could fit the adsorption kinetics processes well. Based on the results of characterization with XPS and XRD, the adsorption mechanisms could be explained as primarily formation of CdCO{sub 3} and Cd(OH){sub 2} precipitation on the surface of serpentine.

  1. Near-wall serpentine cooled turbine airfoil (United States)

    Lee, Ching-Pang


    A serpentine coolant flow path (54A-54G) formed by inner walls (50, 52) in a cavity (49) between pressure and suction side walls (22, 24) of a turbine airfoil (20A). A coolant flow (58) enters (56) an end of the airfoil, flows into a span-wise channel (54A), then flows forward (54B) over the inner surface of the pressure side wall, then turns behind the leading edge (26), and flows back along a forward part of the suction side wall, then follows a loop (54E) forward and back around an inner wall (52), then flows along an intermediate part of the suction side wall, then flows into an aft channel (54G) between the pressure and suction side walls, then exits the trailing edge (28). This provides cooling matched to the heating topography of the airfoil, minimizes differential thermal expansion, revives the coolant, and minimizes the flow volume needed.

  2. Approach to Integrate Global-Sun Models of Magnetic Flux Emergence and Transport for Space Weather Studies (United States)

    Mansour, Nagi N.; Wray, Alan A.; Mehrotra, Piyush; Henney, Carl; Arge, Nick; Godinez, H.; Manchester, Ward; Koller, J.; Kosovichev, A.; Scherrer, P.; hide


    The Sun lies at the center of space weather and is the source of its variability. The primary input to coronal and solar wind models is the activity of the magnetic field in the solar photosphere. Recent advancements in solar observations and numerical simulations provide a basis for developing physics-based models for the dynamics of the magnetic field from the deep convection zone of the Sun to the corona with the goal of providing robust near real-time boundary conditions at the base of space weather forecast models. The goal is to develop new strategic capabilities that enable characterization and prediction of the magnetic field structure and flow dynamics of the Sun by assimilating data from helioseismology and magnetic field observations into physics-based realistic magnetohydrodynamics (MHD) simulations. The integration of first-principle modeling of solar magnetism and flow dynamics with real-time observational data via advanced data assimilation methods is a new, transformative step in space weather research and prediction. This approach will substantially enhance an existing model of magnetic flux distribution and transport developed by the Air Force Research Lab. The development plan is to use the Space Weather Modeling Framework (SWMF) to develop Coupled Models for Emerging flux Simulations (CMES) that couples three existing models: (1) an MHD formulation with the anelastic approximation to simulate the deep convection zone (FSAM code), (2) an MHD formulation with full compressible Navier-Stokes equations and a detailed description of radiative transfer and thermodynamics to simulate near-surface convection and the photosphere (Stagger code), and (3) an MHD formulation with full, compressible Navier-Stokes equations and an approximate description of radiative transfer and heating to simulate the corona (Module in BATS-R-US). CMES will enable simulations of the emergence of magnetic structures from the deep convection zone to the corona. Finally, a plan

  3. Formation of Cool and Warm Jets by Magnetic Flux Emerging from the Solar Chromosphere to Transition Region (United States)

    Yang, Liping; Peter, Hardi; He, Jiansen; Tu, Chuanyi; Wang, Linghua; Zhang, Lei; Yan, Limei


    In the solar atmosphere, jets are ubiquitous at various spatial-temporal scales. They are important for understanding the energy and mass transports in the solar atmosphere. According to recent observational studies, the high-speed network jets are likely to be intermittent but continual sources of mass and energy for the solar wind. Here, we conduct a 2D magnetohydrodynamics simulation to investigate the mechanism of these network jets. A combination of magnetic flux emergence and horizontal advection is used to drive the magnetic reconnection in the transition region between a strong magnetic loop and a background open flux. The simulation results show that not only a fast warm jet, much similar to the network jets, is found, but also an adjacent slow cool jet, mostly like classical spicules, is launched. Differing from the fast warm jet driven by magnetic reconnection, the slow cool jet is mainly accelerated by gradients of both thermal pressure and magnetic pressure near the outer border of the mass-concentrated region compressed by the emerging loop. These results provide a different perspective on our understanding of the formation of both the slow cool jets from the solar chromosphere and the fast warm jets from the solar transition region.

  4. The Eruption of a Small-scale Emerging Flux Rope as the Driver of an M-class Flare and of a Coronal Mass Ejection (United States)

    Yan, X. L.; Jiang, C. W.; Xue, Z. K.; Wang, J. C.; Priest, E. R.; Yang, L. H.; Kong, D. F.; Cao, W. D.; Ji, H. S.


    Solar flares and coronal mass ejections are the most powerful explosions in the Sun. They are major sources of potentially destructive space weather conditions. However, the possible causes of their initiation remain controversial. Using high-resolution data observed by the New Solar Telescope of Big Bear Solar Observaotry, supplemented by Solar Dynamics Observatory observations, we present unusual observations of a small-scale emerging flux rope near a large sunspot, whose eruption produced an M-class flare and a coronal mass ejection. The presence of the small-scale flux rope was indicated by static nonlinear force-free field extrapolation as well as data-driven magnetohydrodynamics modeling of the dynamic evolution of the coronal three-dimensional magnetic field. During the emergence of the flux rope, rotation of satellite sunspots at the footpoints of the flux rope was observed. Meanwhile, the Lorentz force, magnetic energy, vertical current, and transverse fields were increasing during this phase. The free energy from the magnetic flux emergence and twisting magnetic fields is sufficient to power the M-class flare. These observations present, for the first time, the complete process, from the emergence of the small-scale flux rope, to the production of solar eruptions.

  5. Low temperature production and exhalation of methane from serpentinized rocks on Earth: A potential analog for methane production on Mars (United States)

    Etiope, Giuseppe; Ehlmann, Bethany L.; Schoell, Martin


    We evaluate, based on terrestrial analogs, the potential flux, origin and isotopic signature of methane (CH4) from serpentinized or serpentinizing rocks on Mars. The Tekirova ophiolites, in Turkey, have been shown to release, either via focused vents or through diffuse microseepage, substantial amounts of CH4 which could be produced via catalyzed abiotic methanation (Sabatier reaction) at low temperatures (methane production and fractures for release of gas to the atmosphere, similar to those on Earth. A simple, first-order estimation gas-advection model suggests that methane fluxes on the order of several mg m-2 d-1, similar to microseepage observed in terrestrial ophiolites, could occur in martian rocks. High temperature, hydrothermal conditions may not be necessary for abiotic CH4 synthesis on Mars: low temperature (methanation is possible in the presence of catalysts like ruthenium, rhodium or, more commonly, chromium minerals, which occur in terrestrial ophiolites as in martian mantle meteorites. The terrestrial analog environment of abiotic microseepage may thus explain production of methane on Mars in the ancient past or at present. The wide range of martian 12C/13C and D/H ratios and the potential secondary alteration of CH4 by abiotic oxidation, as observed on Earth, could result in large isotope variations of methane on Mars. CH4 isotopic composition alone may not allow definitive determination of biotic vs. abiotic gas origin. Using our terrestrial vs. martian analysis as guide to future Mars exploration we propose that direct methane and ethane gas detection and isotopic measurements on the ground over serpentinized/serpentinizing rocks should be considered in developing future strategies for unraveling the source and origin of methane on Mars.

  6. Ultramafic clasts from the South Chamorro serpentine mud volcano reveal a polyphase serpentinization history of the Mariana forearc mantle (United States)

    Kahl, Wolf-Achim; Jöns, Niels; Bach, Wolfgang; Klein, Frieder; Alt, Jeffrey C.


    Serpentine seamounts located on the outer half of the pervasively fractured Mariana forearc provide an excellent window into the forearc devolatilization processes, which can strongly influence the cycling of volatiles and trace elements in subduction zones. Serpentinized ultramafic clasts recovered from an active mud volcano in the Mariana forearc reveal microstructures, mineral assemblages and compositions that are indicative of a complex polyphase alteration history. Petrologic phase relations and oxygen isotopes suggest that ultramafic clasts were serpentinized at temperatures below 200 °C. Several successive serpentinization events represented by different vein generations with distinct trace element contents can be recognized. Measured in situ Rb/Cs ratios are fairly uniform ranging between 1 and 10, which is consistent with Cs mobilization from sediments at lower temperatures and lends further credence to the low-temperature conditions proposed in models of the thermal structure in forearc settings. Late veins show lower fluid mobile element (FME) concentrations than early veins, suggesting a decreasing influence of fluid discharge from the subducting slab on the composition of the serpentinizing fluids. The continuous microfabric and mineral chemical evolution observed in the ultramafic clasts may have implications as to the origin and nature of the serpentinizing fluids. We hypothesize that opal and smectite dehydration produce quartz-saturated fluids with high FME contents and Rb/Cs between 1 and 4 that cause the early pervasive serpentinization. The partially serpentinized material may then be eroded from the basal plane of the suprasubduction mantle wedge. Serpentinization continued but the interacting fluids did not carry a pronounced sedimentary signature, either because FMEs were no longer released from the slab, or due to an en route loss of FMEs. Late chrysotile veins that document the increased access of fluids in a now fluid-dominated regime are

  7. Helix Electrohydrodynamic Printing of Highly Aligned Serpentine Micro/Nanofibers

    Directory of Open Access Journals (Sweden)

    Yongqing Duan


    Full Text Available Micro/nano serpentine structures have widespread applications in flexible/stretchable electronics; however, challenges still exist for low-cost, high-efficiency and controllable manufacturing. Helix electrohydrodynamic printing (HE-printing has been proposed here to realize controllable direct-writing of large area, highly aligned serpentine micro/nanofibers by introducing the rope coiling effect into printing process. By manipulating the flying trajectory and solidification degree of the micro/nano jet, the solidified micro/nanofiber flying in a stabilized helical manner and versatile serpentine structures deposited on a moving collector have been achieved. Systematic experiments and theoretical analysis were conducted to study the transformation behavior and the size changing rules for various deposited microstructures, and highly aligned serpentine microfibers were directly written by controlling the applied voltage, nozzle-to-collector distance and collector velocity. Furthermore, a hyper-stretchable piezoelectric device that can detect stretching, bending and pressure has been successfully fabricated using the printed serpentine micro/nanofibers, demonstrating the potential of HE-printing in stretchable electronics manufacturing.

  8. Reaction-induced fracturing during olivine serpentinization: A mechanistic investigation at the interface scale

    NARCIS (Netherlands)

    Plümper, O.; Røyne, A.; Malthe-Sørenssen, A.; King, H. E.; Jamtveit, B.

    Serpentinization of the Earth's impermeable upper mantle is one of the most fundamental metamorphic hydration reactions. It governs lithospheric weakening, geochemical subduction zone input and possibly even the formation of life-essential building blocks. Serpentinization relies on fluid pathway

  9. High Pressure Serpentinization Catalysed by Awaruite in Planetary Bodies (United States)

    Neto-Lima, J.; Fernández-Sampedro, M.; Prieto-Ballesteros, O.


    Recent discoveries from planetary missions show that serpentinization process may act significantly on the geological evolution and potential habitability of the icy bodies of the Solar System, like Enceladus or Europa. Here we review the available experimental data so far about methane formation occurring during serpentinization, which is potentially relevant to icy moons, and present our results using awaruite as a catalyst of this process. The efficiency of awaruite and high pressure in the Fischer-Tropsch and Sabatier Type reactions are evaluated here when olivine is incubated.

  10. Separation Of Serpentine From Magnesite By Amine Flotation


    GENCE, Nermin; ÖZDAĞ, Hüseyin


    The aim ofthis work is fo recover magnesite jrom a magnesiîe/serpentine mixture byamme jîoîation. Paramefers svch as ihe type of amine and qvanîity, pH, pıcîp density, îhe effect ofdepressant on ma^nesite, conditionmg time ~were studied. The resulîs sho~wed that amines wereeffective in the separation of magnesiîe/serpentine minerals. The most effective amme \\vasfound tu beArmaflote 14.

  11. Serpentinomics-an emerging new field of study (United States)

    Jessica Wright; Eric von Wettberg


    "Serpentinomics" is an emerging field of study which has the potential to greatly advance our understanding of serpentine ecology. Several newly developing –omic fields, often using high-throughput tools developed for molecular biology, will advance the field of serpentine ecology, or, "serpentinomics." Using tools from the...

  12. High-resolution imaging spectroscopy of two micro-pores and an arch filament system in a small emerging-flux region (United States)

    González Manrique, S. J.; Bello González, N.; Denker, C.


    Context. Emerging flux regions mark the first stage in the accumulation of magnetic flux eventually leading to pores, sunspots, and (complex) active regions. These flux regions are highly dynamic, show a variety of fine structure, and in many cases live only for a short time (less than a day) before dissolving quickly into the ubiquitous quiet-Sun magnetic field. Aims: The purpose of this investigation is to characterize the temporal evolution of a minute emerging flux region, the associated photospheric and chromospheric flow fields, and the properties of the accompanying arch filament system. We aim to explore flux emergence and decay processes and investigate if they scale with structure size and magnetic flux contents. Methods: This study is based on imaging spectroscopy with the Göttingen Fabry-Pérot Interferometer at the Vacuum Tower Telescope, Observatorio del Teide, Tenerife, Spain on 2008 August 7. Photospheric horizontal proper motions were measured with Local correlation tracking using broadband images restored with multi-object multi-frame blind deconvolution. Cloud model (CM) inversions of line scans in the strong chromospheric absorption Hαλ656.28 nm line yielded CM parameters (Doppler velocity, Doppler width, optical thickness, and source function), which describe the cool plasma contained in the arch filament system. Results: The high-resolution observations cover the decay and convergence of two micro-pores with diameters of less than one arcsecond and provide decay rates for intensity and area. The photospheric horizontal flow speed is suppressed near the two micro-pores indicating that the magnetic field is already sufficiently strong to affect the convective energy transport. The micro-pores are accompanied by a small arch filament system as seen in Hα, where small-scale loops connect two regions with Hα line-core brightenings containing an emerging flux region with opposite polarities. The Doppler width, optical thickness, and source

  13. The effect of polyether on the separation of pentlandite and serpentine

    Directory of Open Access Journals (Sweden)

    Xiaowen Zhou


    Full Text Available The effect of polyether on the separation of pentlandite from serpentine has been studied. In addition to flotation and sedimentation tests, electrophoresis and adsorption tests have been conducted. The flotation and sedimentation results show that serpentine impairs flotation performance of pentlandite, by adhering to the pentlandite particles. Addition of the polyether could promote the dispersion of the mixed sample of pentlandite and serpentine in alkaline conditions and significantly reduce adverse effects of serpentine on the pentlandite flotation. The electrophoresis and adsorption tests show that polyether can selectively adsorb onto pentlandite surface through hydrophobic reaction and remove serpentine slime particles from pentlandite surfaces by steric hindrance effect.

  14. Influence of temperature, pressure, and fluid salinity on the distribution of chlorine into serpentine minerals (United States)

    Huang, Ruifang; Sun, Weidong; Zhan, Wenhuan; Ding, Xing; Zhu, Jihao; Liu, Jiqiang


    Serpentinization produces serpentine minerals that have abundant water and fluid-mobile elements (e.g., Ba, Cs, and Cl). The dehydration of serpentine minerals produces chlorine-rich fluids that may be linked with the genesis of arc magmas. However, the factors that control the distribution of chlorine into serpentine minerals remain poorly constrained. We performed serpentinization experiments at 80-500 °C and pressures from vapor saturated pressures to 20 kbar on peridotite, orthopyroxene, and olivine with salinity greatly decreased chlorine concentrations of olivine-derived serpentine produced at 400 °C and 3.0 kbar, which was associated with a decrease in silica mobility during serpentinization. By contrast, influence of fluid salinity at 311 °C and 3.0 kbar is minor. Moreover, chlorine distribution into serpentine can be influenced by primary minerals of serpentine. Serpentine formed in olivine-only experiments at 311 °C and 3.0 kbar had 0.08 ± 0.03 wt% Cl, which is significantly lower than chlorine concentrations of serpentine minerals (0.49 ± 0.36 wt%) produced in orthopyroxene-only experiments. By contrast, for experiments at 311 °C and 3.0 kbar, olivine- and orthopyroxene-derived serpentine had comparable amounts of chlorine. In particular, olivine-derived serpentine had 0.16 ± 0.09 wt% Cl that was slightly higher than chlorine concentrations of serpentine formed in olivine-only experiments, whereas orthopyroxene-derived serpentine had significantly lower chlorine concentrations than that formed in orthopyroxene-only experiments. The contrast may be associated with releases of aluminum and silica from pyroxene minerals, which possibly results in a decrease in chlorine concentrations of serpentine. The concentrations of chlorine in serpentine formed in experiments at 311 °C and 3.0 kbar were slightly lower than those in serpentine produced at 300 °C and 8.0 kbar, which may be associated with influence of pressure on the mobility of iron and silica

  15. Dynamics of soil chemistry in different serpentine habitats from Serbia

    Directory of Open Access Journals (Sweden)

    Vicić Dražen D.


    Full Text Available To enhance understanding of edaphic conditions in serpentine habitats, a thorough investigation of chemical and mechanical properties of three soils from disjunct ultramafic outcrops in the central Balkans was undertaken. Soil from a nearby chemically-contrasting limestone habitat was also analyzed. Three plant species differently associated with serpentine (Halacsya sendtneri, Cheilanthes marantae, and Seseli rigidum were references for site and soil selection. Twenty elements were scanned for, and fourteen were measured in seven sequentially-extracted soil fractions. Quantified soil properties also included: pH, levels of free CaCO3, organic matter, P2O5, K2O, N, C, S, cation exchange capacity, total organic carbon, field capacity and soil mechanical composition. The usual harsh components for plant growth in serpentine soil such as elevated Mg:Ca ratio, high levels of Ni, Cr, or Co, were significantly lower in the available fractions. There was a significant positive correlation of organic matter and field capacity, with most available Ca (70-80% found in the mobile, rather than the organically-bound fraction. This showed that a more favorable Mg:Ca ratio is highly dependent upon a higher field capacity, which is also in accordance with a more developed vegetation. Increasing the availability of metals (Al, Ba, Ca, Cr, Cu, Mg, Ni, Zn in a more developed serpentine grassland and forest vegetation, occurred only simultaneously with decrease of the Mg:Ca ratio and rise in other factors of fertility (N, P, K. Progressive development of ecosystem complexity therefore raised the availability of metals, but also reduced harsh Mg:Ca ratio disproportion, boosted levels of nutrients and raised soil field capacity. Principal components analysis confirmed that the main differences among serpentine habitats lay primarily in factors of fertility. The common habitat which hosts all three reference species offers intermediate conditions in a plant habitat

  16. Slip on serpentine detachments at magma-poor margins (United States)

    Reston, Timothy; Lymer, Gael; Cresswell, Derren; Stevenson, Carl; Bull, Jonathan; Sawyer, Dale; Morgan, Julia; Galicia 3D working Group


    At magma-poor margins, the structures formed during rifting are not obscured by thick lavas, allowing detailed analysis of the tectonics of rifting and breakup. At most of these margins, the mantle beneath the thin crust has unusually low velocities, interpreted as a consequence of serpentinization following the embrittlement of the crust during rifting; models for the onset of serpentinization predict the thicknesses of crust that are observed at the landward limit of the serpentinized mantle. At a handful of margins the top of the serpentinized mantle appears to have acted as a detachment or decollement: faults that bound the overlying crustal blocks root on a bright reflection at the base of these blocks. Examples include the P reflection west of Ireland, the H reflection west of northern Portugal, and the S reflector west of Galicia. Corrugations observed on a 3D volume collected in 2013 above the S reflector strongly support its interpretation as a slip surface. A remaining question is whether slip on these "serpentine detachments" occurred at low-angle or not: for typical friction coefficients of 0.7, normal faults should lock-up and be replaced by steeper faults once they have rotated to perhaps 35°, an observation consistent with earthquake data. This angle can be reduced to 20-25° if the fault zone is composed of weak minerals such as serpentine. One possibility is that the detachment is actually composed of segments of faults that were active sequentially in a rolling hinge model. Beneath the centre of the Porcupine basin, the P reflection is sub-horizontal but its western continuation dips beneath the Porcupine bank at 20-25°, consistent with slip on serpentine-weakened rolling hinge system. West of Galicia, based on the geometrical relationships between late synrift wedges and their bounding faults which root on S, S has been interpreted to have slipped at angles below 20-25°. However, a 3D dataset collected over S in 2013 provides the opportunity

  17. The effect of quartz on the flotation of pyrite depressed by serpentine

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    Bo Feng


    Full Text Available The effect of quartz particles on the flotation of pyrite depressed by serpentine has been investigated through flotation tests, adsorption tests, zeta potential measurements and DLVO calculation. The results show that the presence of hydrophilic serpentine slimes on pyrite surface reduces collector adsorption and results in lower recovery of pyrite. The finer the serpentine slime is, the lower the pyrite recovery will be. Quartz particles do not interfere with pyrite flotation. However, the addition of quartz particles increases the adsorption of collector on pyrite surface and limits the detrimental effect of serpentine on pyrite flotation. The fine-grained quartz is more effective. Zeta potential measurements and DLVO calculation illustrate that the zeta potential of quartz is more negative than that of pyrite and the attraction force between serpentine and quartz is stronger than force between serpentine and pyrite, thus some serpentine slimes were transferred from pyrite surface to quartz in the process of attrition.

  18. Tribological Properties of NiAl Matrix Composites Filled with Serpentine Powders (United States)

    Xue, Bing; Jing, Peixing; Ma, Weidong


    The unexplored tribological properties of NiAl matrix composites filled with serpentine powders are investigated using a reciprocating ball-on-disk configuration. Tribological test results reveal that increasing the serpentine concentration to some extent reduces the friction coefficients and wear rates of the composites. The best anti-friction and anti-wear performance is displayed by the NiAl matrix composite filled with 8 wt.% serpentine and 2 wt.% TiC (NAST). Microstructural analyses demonstrate that after adding serpentine, the self-lubricating films with different percentages of coverage form on the worn surfaces of the composites. A self-lubricating film with the highest percentage of coverage smears on the worn surface of NAST. This clearly suggests that serpentine can act as a new type of filler for NiAl matrix composites, whereas a combination of serpentine and TiC can enable serpentine to provide a full play to its excellent lubricating performance.


    Energy Technology Data Exchange (ETDEWEB)

    Chatterjee, Piyali; Fan, Yuhong, E-mail: [High Altitude Observatory, National Center for Atmospheric Research, 3080 Center Green Drive, Boulder, CO 80301 (United States)


    We report the first results of a magnetohydrodynamic simulation of the development of a homologous sequence of three coronal mass ejections (CMEs) and demonstrate their so-called cannibalistic behavior. These CMEs originate from the repeated formations and partial eruptions of kink unstable flux ropes as a result of continued emergence of a twisted flux rope across the lower boundary into a pre-existing coronal potential arcade field. The simulation shows that a CME erupting into the open magnetic field created by a preceding CME has a higher speed. The second of the three successive CMEs is cannibalistic, catching up and merging with the first into a single fast CME before exiting the domain. All the CMEs including the leading merged CME, attained speeds of about 1000 km s{sup –1} as they exit the domain. The reformation of a twisted flux rope after each CME eruption during the sustained flux emergence can naturally explain the X-ray observations of repeated reformations of sigmoids and ''sigmoid-under-cusp'' configurations at a low-coronal source of homologous CMEs.

  20. Serpentinization: Getting water into a low permeability peridotite (United States)

    Ulven, Ole Ivar


    Fluid consuming rock transformation processes occur in a variety of settings in the Earth's crust. One such process is serpentinization, which involves hydration of ultramafic rock to form serpentine. With peridotite being one of the dominating rocks in the oceanic crust, this process changes physical and chemical properties of the crust at a large scale, increases the amount of water that enters subduction zones, and might even affect plate tectonics te{jamtveit}. A significant number of papers have studied serpentinization in different settings, from reaction fronts progressing over hundreds of meters te{rudge} to the interface scale fracture initiation te{pluemper}. However, the process represents a complicated multi-physics problem which couples external stress, mechanical deformation, volume change, fracture formation, fluid transport, the chemical reaction, heat production and heat flow. Even though it has been argued that fracture formation caused by the volume expansion allows fluid infiltration into the peridotite te{rudge}, it remains unclear how sufficient water can enter the initially low permeability peridotite to pervasively serpentinize the rock at kilometre scale. In this work, we study serpentinization numerically utilizing a thermo-hydro-mechanical model extended with a fluid consuming chemical reaction that increases the rock volume, reduces its density and strength, changes the permeability of the rock, and potentially induces fracture formation. The two-way coupled hydromechanical model is based on a discrete element model (DEM) previously used to study a volume expanding process te{ulven_1,ulven_2} combined with a fluid transport model based on poroelasticity te{ulven_sun}, which is here extended to include fluid unsaturated conditions. Finally, a new model for reactive heat production and heat flow is introduced, to make this probably the first ever fully coupled chemo-thermo-hydromechanical model describing serpentinization. With this model

  1. The Impact of Nanoparticles on Forced Convection in a Serpentine Microchannel

    Directory of Open Access Journals (Sweden)

    P. Rahim Mashaei


    Full Text Available In this study heat transfer and fluid flow characteristics of Al2O3/water nanofluid in a serpentine microchannel is numerically investigated. A constant heat flux is applied on microchannel wall and a single-phase model has been adopted using temperature-dependent properties. The effects of pertinent factors such as Reynolds number (Re=10, 20, 50 and 100, particle volume fraction (=0(distilled water, 2, 4 and 8% and heat flux (q=5, 10 and 15 W/cm2, on the velocity and temperature field, average heat transfer coefficient (havg, pressure drop (Δp, and thermal-hydraulic performance (η are evaluated. The results show that the use of nanofluid causes increased velocity gradient near the wall which is more remarkable for φ = 8%. The results also reveal that the heat transfer rate increases as nanoparticle volume fraction and Reynold number increase and a maximum value 51% in the average heat transfer coefficient is detected among all the considered cases when compared to basefluid (i.e., water. It is found that a higher heat flux leads to heat transfer enhancement and reduction in pressure drop. Finally, thermal-hydraulic performance is calculated and it is seen that the best performance occurs for Re =10 and φ = 4%.

  2. Electrokinetic focusing and filtration of cells in a serpentine microchannel (United States)

    Church, Christopher; Zhu, Junjie; Wang, Gaoyan; Tzeng, Tzuen-Rong J.; Xuan, Xiangchun


    Focusing cells into a single stream is usually a necessary step prior to counting and separating them in microfluidic devices such as flow cytometers and cell sorters. This work presents a sheathless electrokinetic focusing of yeast cells in a planar serpentine microchannel using dc-biased ac electric fields. The concurrent pumping and focusing of yeast cells arise from the dc electrokinetic transport and the turn-induced ac∕dc dielectrophoretic motion, respectively. The effects of electric field (including ac to dc field ratio and ac field frequency) and concentration (including buffer concentration and cell concentration) on the cell focusing performance were studied experimentally and numerically. A continuous electrokinetic filtration of E. coli cells from yeast cells was also demonstrated via their differential electrokinetic focusing in a serpentine microchannel. PMID:20216971

  3. Serpentine Thermal Coupling Between a Stream and a Conducting Body

    Energy Technology Data Exchange (ETDEWEB)

    Kobayashi, H.; Lorente, S.; Anderson, R.; Bejan, A.


    Here we document the effect of flow configuration on the heat transfer performance of a serpentine shaped stream embedded in a conducting solid. Several configurations with fixed volume of fluid are considered: U-shaped with varying spacing between the parallel portions of the U, serpentine shapes with three elbows, and conducting soil with several parallelepipedal shapes. We show that the spacing must be greater than a critical value in order for the heat transfer density of the stream-solid configuration to be the highest that it can be. Spacings larger than this critical value do not yield improvements in heat transfer density. We also show that even though the heat transfer is time dependent, the stream-solid configuration has an effective number of heat transfer units Ntu that is nearly constant in time. The larger Ntu values correspond to the configurations with greater heat transfer density.

  4. Numerical Modeling of Brine Formation and Serpentinization at the Rainbow Hydrothermal System (United States)

    Sekhar, P.; Lowell, R. P.


    The Rainbow hydrothermal field on the Mid Atlantic Ridge is a high-temperature hydrothermal system hosted in peridotite. The vent fluids are rich in methane and hydrogen suggesting that serpentinization is occurring at depth in the system. Vent temperature of ~365°C, salinity of ~4.5 wt%, and heat output of ~500 MW suggest that Rainbow field is driven by a magmatic heat source and that phase separation is occurring at depth. To understand the origin of high salinity in the Rainbow hydrothermal fluid, we construct a 2D numerical model of two-phase hydrothermal circulation using the numerical simulator FISHES. This code uses the finite volume method to solve the conservation of mass, momentum, energy, and salt equations in a NaCl-H2O fluid. We simulate convection in an open top 2D box at a surface pressure of 23 MPa and seawater temperature of 10oC. The bottom and sides of the box are insulated and impermeable, and a fixed temperature distribution is maintained at the base to ensure phase separation. We first consider a homogeneous model with a permeability of 10-13 m2 and system depths of 2 and 1 km, respectively. The brine-derived fluid from the deeper system barely exceeds seawater, whereas the shallower system produces a short pulse of 9.0 wt% for 5 years. We then consider 1 km deep systems with a high permeability discharge zone of 5x10-13 m2 that corresponds to a fault zone, surrounded by recharge zones of 10-13, 10-14 and 10-15 m2, respectively. The model with recharge permeability of 10-14 m2 yields stable plumes that vent brine-derived fluid of 4.2 wt% for 150 years. Using the quasi- steady state of this model as a base, we estimate the rate of serpentinization along the fluid flow paths, and evolution of porosity and permeability. This analysis will indicate the extent to which serpentinization will affect the dynamics of the system and will provide insight into methane flux in the Rainbow vent field.

  5. An ensemble approach to the study of the emergence of metabolic and proliferative disorders via Flux Balance Analysis

    Directory of Open Access Journals (Sweden)

    Giancarlo Mauri


    Full Text Available An extensive rewiring of cell metabolism supports enhanced proliferation in cancer cells. We propose a systems level approach to describe this phenomenon based on Flux Balance Analysis (FBA. The approach does not explicit a cell biomass formation reaction to be maximized, but takes into account an ensemble of alternative flux distributions that match the cancer metabolic rewiring (CMR phenotype description. The underlying concept is that the analysis the common/distinguishing properties of the ensemble can provide indications on how CMR is achieved and sustained and thus on how it can be controlled.

  6. Serpentine and the chemical evolution of the earth's mantle (United States)

    Ruepke, L.; Phipps Morgan, J.; Hort, M.; Connolly, J.; Ranero, C.


    Hydration and dehydration of oceanic lithosphere play an important role in element recycling at convergent margins. Most studies agree that subduction related recycling is necessary to explain some aspects of the mantle's chemical evolution. However, some of these recycling processes are not yet well understood, for example (1) OIB type lavas sometimes show a radiogenic 206Pb/204Pb component commonly termed HIMU whose origin is yet to be exactly determined. (2) What is the fate of rare gases during subduction? Does a previously proposed 'subduction barrier' exist and prevent deep recycling of all rare gases, so that todays atmosphere's content reflects the total of degassed rare gases? Here we explore the potential impact of slab serpentinization and deserpentinization processes on arc-melting and on water, U, Pb, and noble gas recycling into the deep mantle. We examine the consequences of a scenario in which bend-faulting between the outer rise and trench axis creates the conduits for seawater to reach and react with cold lithospheric mantle to serpentinize it. If this process occurs, then the incoming lithosphere will typically contain ˜500m of altered sediments, ˜6km of partially hydrated oceanic crust, and ˜20-55km of partially serpentinized slab mantle. Our thermomechanical modelling implies strong deep recycling (30-90%) of the slab's chemical water, depending upon slab age and subduction rate. Possible global geochemical consequences of this scenario are: 1) At current subduction rates, 0.5-1.5 oceans of water would be recycled past the arc-melting region into the deeper mantle during the past Ga. ) Since 0.3%, 1%, and 3% of the exosphere's Ne, Ar, and Xe are dissolved in the oceans, this implies that at present rates ˜0.02, ˜0.06, and ˜0.2 'atmospheres' of Ne, Ar, and Xe, respectively, would have been recycled into the mantle during the past 4 Ga. These numbers imply that dissolved rare gases were transported at bulk-seawater concentrations during

  7. Experimental investigation of heat transfer and pressure drop characteristics of water and glycol-water mixture in multi-port serpentine microchannel slab heat exchangers (United States)

    Khan, Md Mesbah-ul Ghani

    Microchannels have several advantages over traditional large tubes. Heat transfer using microchannels recently have attracted significant research and industrial design interests. Open literatures leave with question on the applicability of classical macroscale theory in microchannels. Better understanding of heat transfer in various microchannel geometries and building experimental database are continuously urged. The purpose of this study is to contribute the findings and data to this emerging area through carefully designed and well controlled experimental works. The commercially important glycol-water mixture heat transfer fluid and multiport slab serpentine heat exchangers are encountered in heating and cooling areas, e.g. in automotive, aircraft, and HVAC industries. For a given heat duty, the large diameter tubes experience turbulent flow whereas the narrow channels face laminar flow and often developing flow. Study of low Reynolds number developing glycol-water mixture laminar flow in serpentine microchannel heat exchanger with parallel multi-port slab is not available in the open literature. Current research therefore experimentally investigates glycol-water mixture and water in simultaneously developing laminar flows. Three multiport microchannel heat exchangers; straight and serpentine slabs, are used for each fluid. Friction factors of glycol-water mixture and water flows in straight slabs are higher than conventional fully developed laminar flow. If a comprehensive pressure balance is introduced, the results are well compared with conventional Poiseuille theory. Similar results are found in serpentine slab. The pressure drop for the straight core is the highest, manifolds are the intermediate, and serpentine is the least; which are beneficial for heat exchangers. The heat transfer results in serpentine slab for glycol-water mixture and water are higher and could not be compared with conventional fully developed and developing flow correlations. New

  8. Origin of the High-speed Jets Fom Magnetic Flux Emergence in the Solar Transition Region as well as Their Mass and Energy Contribuctions to the Solar Wind (United States)

    Liping, Y.; He, J.; Peter, H.; Tu, C. Y.; Feng, X. S.


    In the solar atmosphere, the jets are ubiquitous and found to be at various spatia-temporal scales. They are significant to understand energy and mass transport in the solar atmosphere. Recently, the high-speed transition region jets are reported from the observation. Here we conduct a numerical simulation to investigate the mechanism in their formation, as well as their mass and energy contributions to the solar wind. Driven by the supergranular convection motion, the magnetic reconnection between the magnetic loop and the background open flux occurring in the transition region is simulated with a two-dimensional MHD model. The simulation results show that not only a fast hot jet, much resemble the found transition region jets, but also a adjacent slow cool jet, mostly like classical spicules, is launched. The force analysis shows that the fast hot jet is continually driven by the Lorentz force around the reconnection region, while the slow cool jet is induced by an initial kick through the Lorentz force associated with the emerging magnetic flux. Also, the features of the driven jets change with the amount of the emerging magnetic flux, giving the varieties of both jets.With the developed one-dimensional hydrodynamic solar wind model, the time-dependent pulses are imposed at the bottom to simulate the jet behaviors. The simulation results show that without other energy source, the injected plasmas are accelerated effectively to be a transonic wind with a substantial mass flux. The rapid acceleration occurs close to the Sun, and the resulting asymptotic speeds, number density at 0.3 AU, as well as mass flux normalized to 1 AU are compatible with in site observations. As a result of the high speed, the imposed pulses lead to a train of shocks traveling upward. By tracing the motions of the injected plasma, it is found that these shocks heat and accelerate the injected plasma to make part of them propagate upward and eventually escape. The parametric study shows

  9. High-pressure creep of serpentine, interseismic deformation, and initiation of subduction. (United States)

    Hilairet, Nadege; Reynard, Bruno; Wang, Yanbin; Daniel, Isabelle; Merkel, Sebastien; Nishiyama, Norimasa; Petitgirard, Sylvain


    The supposed low viscosity of serpentine may strongly influence subduction-zone dynamics at all time scales, but until now its role could not be quantified because measurements relevant to intermediate-depth settings were lacking. Deformation experiments on the serpentine antigorite at high pressures and temperatures (1 to 4 gigapascals, 200 degrees to 500 degrees C) showed that the viscosity of serpentine is much lower than that of the major mantle-forming minerals. Regardless of the temperature, low-viscosity serpentinized mantle at the slab surface can localize deformation, impede stress buildup, and limit the downdip propagation of large earthquakes at subduction zones. Antigorite enables viscous relaxation with characteristic times comparable to those of long-term postseismic deformations after large earthquakes and slow earthquakes. Antigorite viscosity is sufficiently low to make serpentinized faults in the oceanic lithosphere a site for subduction initiation.

  10. Geochemical bioenergetics during low-temperature serpentinization: An example from the Samail ophiolite, Sultanate of Oman (United States)

    Canovas, Peter A.; Hoehler, Tori; Shock, Everett L.


    Various classes of microbial and biomolecular evidence from global studies in marine and continental settings are used to identify a set of reactions that appear to support microbial metabolism during serpentinization of ultramafic rocks. Geochemical data from serpentinizing ecosystems in the Samail ophiolite of Oman are used to evaluate the extent of disequilibria that can support this set of microbial metabolisms and to provide a ranking of potential metabolic energy sources in hyperalkaline fluids that are direct products of serpentinization. Results are used to construct hypotheses for how microbial metabolism may be supported in the subsurface for two cases: ecosystems hosted in rocks that have already undergone significant serpentinization and those hosted by deeper, active serpentinization processes.

  11. Impact-induced water loss from serpentine, nontronite and kernite (United States)

    Boslough, M. B.; Weldon, R. J.; Ahrens, T. J.


    Preliminary experiments have been conducted to study shock-release of volatiles from minerals. Impact-induced loss of bound water from hydrous minerals has been observed, using infrared absorption and X-ray powder diffractometer techniques. Serpentine (Mg3Si2O5(OH)4) and nontronite (.5Ca(0.7)Fe4/(Si(7.3)Al(0.7))O20/(OH)4.nH2O) were shocked and recovered from pressures of up to 38 GPa, using one-dimensional shock reverberation techniques. Kernite (Na2B4O7.4H2O) was impacted by a spherical pyrex projectile traveling at 4.89 km/sec, which produced a peak pressure of approximately 33 GPa. The infrared absorption spectra indicate that some of the bound water from these three minerals was released as a result of shock compression and subsequent rarefaction. This evidence is supported by the recovery of small amounts of vapor from the serpentine shocked to 23.5 GPa and the nontronite shocked to 18 GPa. The recovered vapor is inferred to be water from the shocked minerals. X-ray diffraction spectra indicate no major changes in the unit cell dimensions of the two silicates, except for a decrease in the lattice constant in the c-direction of the nontronite, consistent with the loss of interlayer water.

  12. An inverted continental Moho and serpentinization of the forearc mantle. (United States)

    Bostock, M G; Hyndman, R D; Rondenay, S; Peacock, S M


    Volatiles that are transported by subducting lithospheric plates to depths greater than 100 km are thought to induce partial melting in the overlying mantle wedge, resulting in arc magmatism and the addition of significant quantities of material to the overlying lithosphere. Asthenospheric flow and upwelling within the wedge produce increased lithospheric temperatures in this back-arc region, but the forearc mantle (in the corner of the wedge) is thought to be significantly cooler. Here we explore the structure of the mantle wedge in the southern Cascadia subduction zone using scattered teleseismic waves recorded on a dense portable array of broadband seismometers. We find very low shear-wave velocities in the cold forearc mantle indicated by the exceptional occurrence of an 'inverted' continental Moho, which reverts to normal polarity seaward of the Cascade arc. This observation provides compelling evidence for a highly hydrated and serpentinized forearc region, consistent with thermal and petrological models of the forearc mantle wedge. This serpentinized material is thought to have low strength and may therefore control the down-dip rupture limit of great thrust earthquakes, as well as the nature of large-scale flow in the mantle wedge.

  13. CFD Models of a Serpentine Inlet, Fan, and Nozzle (United States)

    Chima, R. V.; Arend, D. J.; Castner, R. S.; Slater, J. W.; Truax, P. P.


    Several computational fluid dynamics (CFD) codes were used to analyze the Versatile Integrated Inlet Propulsion Aerodynamics Rig (VIIPAR) located at NASA Glenn Research Center. The rig consists of a serpentine inlet, a rake assembly, inlet guide vanes, a 12-in. diameter tip-turbine driven fan stage, exit rakes or probes, and an exhaust nozzle with a translating centerbody. The analyses were done to develop computational capabilities for modeling inlet/fan interaction and to help interpret experimental data. Three-dimensional Reynolds averaged Navier-Stokes (RANS) calculations of the fan stage were used to predict the operating line of the stage, the effects of leakage from the turbine stream, and the effects of inlet guide vane (IGV) setting angle. Coupled axisymmetric calculations of a bellmouth, fan, and nozzle were used to develop techniques for coupling codes together and to investigate possible effects of the nozzle on the fan. RANS calculations of the serpentine inlet were coupled to Euler calculations of the fan to investigate the complete inlet/fan system. Computed wall static pressures along the inlet centerline agreed reasonably well with experimental data but computed total pressures at the aerodynamic interface plane (AIP) showed significant differences from the data. Inlet distortion was shown to reduce the fan corrected flow and pressure ratio, and was not completely eliminated by passage through the fan

  14. Holy flux: Spatial and temporal variation in massive pulses of emerging insect biomass from western U.S. rivers (United States)

    Walters, David; Wesner, Jeff S.; Zuellig, Robert E.; Kowalski, Dan A.; Kondratieff, Matt C.


    The river stonefly, Pteronarcys californica (aka salmonfly), is an iconic insect in rivers of western North America due to its large size and its support of economically important species like wild trout (Nehring et al. 2011). Their emergence generates a large economic subsidy to local communities, as anglers from around the world travel to western rivers to fish the salmonfly “hatch” (e.g., Willoughby 2013). Salmonflies, which have a 4-yr lifespan in the central Rocky Mountains (Nehring et al. 2011), emerge en masse during 1 week in late spring (Sheldon 1999), and more than 20 terrestrial species, including humans, are known to eat adult salmonflies (Muttkowski 1925, Sutton 1985, Rockwell et al. 2009). How they influence populations of insectivores or the broader river-riparian ecosystem is unknown; this itself is an issue because salmonflies are disappearing from some rivers (Nehring et al. 2011).

  15. Nuclear microprobe analysis of serpentine from the mid-Atlantic ridge

    Energy Technology Data Exchange (ETDEWEB)

    Orberger, Beate E-mail:; Metrich, Nicole; Mosbah, Michelle E-mail:; Mevel, Catherine; Fouquet, Yves


    At mid-ocean ridges, ultramafic rocks are serpentinized by interaction with seawater-derived fluids. Elements, dissolved in large quantities in seawater, e.g., Na, K, Cl, Br, Ca and Sr, can be, in small amounts, incorporated as traces into the crystal structure of the various serpentine minerals (Mg{sub 3}Si{sub 2}O{sub 5}(OH){sub 4}). These trace elements can be used to track the composition of the reacting fluids and to constrain physico-chemical conditions. This paper represents the first application of particle-induced X- and {gamma}-ray emission (PIXE/PIGE) analysis to serpentine using the nuclear microprobe at the Laboratoire Pierre Suee (CEA-CNRS). Three types of serpentine, belonging to two different serpentinization generations, have been analysed in samples collected from the Mid-Atlantic Ridge (14 deg. 45'N/45 deg. W) that exposes serpentinized peridotites on which the Logachev black smoker is placed. The trace elements Cl, F, S, Cu, Zn, Ca, K, Ni, Cr and Mn were detected from several tens to several thousands of ppm. Bromine, As and Sr are close to the detection limit of about 5 ppm. The trace element concentrations and interelement relationships in serpentines vary (a) with the serpentine type and (b) with the geographic location to the black smoker. Chlorine and in part S originated from seawater, whereas Cu, Zn, Ca, K, Ni, Cr and Fe and the major amount of S were mobilized from the unaltered host rock and partitioned between the serpentine and the aqueous solution.

  16. Abiotic Methane in Land-Based Serpentinized Peridotites: New Discoveries and Isotope Surprises (United States)

    Whiticar, M. J.; Etiope, G.


    Until 2008, abiotic methane in land-based serpentinized ultramafic rocks was documented (including gas and C- and H- isotope compositions) only at sites in Oman, Philippines, New Zealand and Turkey. Methane emanates from seeps and/or hyperalkaline water springs along faults and is associated with molecular hydrogen. These were considered to be very unusual and rare occurrences of gas. Now, methane is documented for peridotite-based springs or seeps (in ophiolites, orogenic massifs or intrusions) in US, Canada, Costa Rica, Greece, Italy, Japan, New Caledonia, Portugal, Spain and United Arab Emirates. Gas flux measurements are indicating that methane can also flux as invisible microseepages from the ground, through fractured peridotites, even far removed from seeps and springs. Methane C-isotope ratios range from -6 to -37 permil (VPDB) for dominantly abiotic methane. The more 13-C depleted values, e.g., California, are likely mixed with biotic gas (microbial and thermogenic gas). Methane H-isotope ratios cover a wide range from -118 to -333 permil (VSMOW). The combination of C- and H-isotopes clearly distinguish biotic from abiotic methane. Radiocarbon (14-C) analysis from bubbling seeps in Italian peridotites indicate that the methane is fossil (pMC <0.2), i.e., older than 50,000 years, similar to the Chimaera seeps in Turkey. So, methane observed in the hyperalkaline waters cannot be produced in the same waters because these are only a few thousands years old. The low temperatures of land-based peridotites (generally <100 °C at depths of 3-4 km) also constrain methane production. We discuss some hypotheses concerning gas generation in water vs. dry systems, i.e., in deeper, older, waters or in unsaturated rocks). We also discuss low vs. high temperatures, i.e., at the present-day low T conditions or at higher temperatures eventually occurring in the early stages of peridotite emplacement on land.

  17. Microjet flow control in an ultra-compact serpentine inlet

    Directory of Open Access Journals (Sweden)

    Da Xingya


    Full Text Available Microjets are used to control the internal flow to improve the performance of an ultra-compact serpentine inlet. A highly offset serpentine inlet with length-to-diameter ratio of 2.5 is designed and static tests are conducted to analyze the internal flow characteristics in terms of pressure recovery, distortion and flow separation. Flow separation is encountered in the second S-turn, and two strong counter-rotating vortices are formed at the aerodynamic interface plane (AIP face which occupy a quarter of the outlet area and result in severe pressure loss and distortion. A flow control model employing a row of microjets in the second turn is designed based on the internal flow characteristics and simplified CFD simulations. Flow control tests are conducted to verify the control effectiveness and understand the characteristics as a function of inlet throat Mach number, injection mass flow ratio, jet Mach number and momentum coefficient. At all test Mach numbers, microjet flow control (MFC effectively improves the recovery and reduces the distortion intensity. Between inlet throat Mach number 0.2 and 0.5, the strong flow separation in the second S-turn is suppressed at an optimum jet flow ratio of less than 0.65%, resulting in a maximum improvement of 4% for pressure recovery coefficient and a maximum decrease of 75% for circumferential distortion intensity at cruise. However, in order to suppress the flow separation, the injection rate should retain in an effective range. When the injection rate is higher than this range, the flow is degraded and the distortion contour is changed from 90° circumferential distortion pattern to 180° circumferential distortion pattern. Detailed data analysis shows that this optimum flow ratio depends on inlet throat Mach number and the momentum coefficient affects the control effectiveness in a dual stepping manner.

  18. Polyphase serpentinization history of Mariana forearc mantle: observations on the microfabric of ultramafic clasts from ODP Leg 195, Site 1200 (United States)

    Kahl, Wolf-Achim; Jöns, Niels; Bach, Wolfgang; Klein, Frieder


    In the forearc of the Mariana subduction zone system, a number of seamounts form from extrusion of blueschist and serpentine mud. Ocean Drilling Program Leg 195 drilled the South Chamorro seamount, where ultramafic clasts occur within the mud matrix. These clasts show a complex serpentinization history, which bears the potential for tracking the alteration history during uplift and cooling of mantle wedge rocks to the seafloor. Moreover, the microfabrics of the highly serpentinized harzburgite and dunite clasts exhibit evidence for multiple fracturing events in the forearc mantle. These, in turn, lead to fluid influx and varied styles of serpentinization of harzburgite and dunite. The serpentinized ultramafic clasts exhibit a variety of microfabrics that range from virtually undeformed to strongly deformed samples. Pervasively serpentinized harzburgites feature either an equigranular fabric of serpentinized olivine and orthopyroxene crystals, or different vein generations related to multiple stages of serpentinization. Several types of fluid pathways in harzburgites are present: (i) veins containing brucite and iron oxides, developed linearly without marked conformance with the rock fabric. In places, these veins developed mm-cm wide halos with finger-shaped serpentinization fronts. Veins of type (i) are either developed as syntaxial veins from a single crack-seal event with large magnetite crystals growing from one wall to the other (as confirmed with high-resolution X-ray microtomography), or formed by multiple fluid events. (ii) serpentine veins that encompass regions of marginally serpentinized, microgranular olivine and large orthopyroxene crystals. (iii) extensional serpentine veins (known as "Frankenstein" type). In the clasts studied, their occurrence is restricted to the halo region of type (i) veins. (iv) as a late-stage feature, extensional veins documenting multiple crack-seal events can be present in the serpentinites (either in undeformed regions with

  19. The production of iron oxide during peridotite serpentinization: Influence of pyroxene

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    Ruifang Huang


    Full Text Available Serpentinization produces molecular hydrogen (H2 that can support communities of microorganisms in hydrothermal fields; H2 results from the oxidation of ferrous iron in olivine and pyroxene into ferric iron, and consequently iron oxide (magnetite or hematite forms. However, the mechanisms that control H2 and iron oxide formation are poorly constrained. In this study, we performed serpentinization experiments at 311 °C and 3.0 kbar on olivine (with <5% pyroxene, orthopyroxene, and peridotite. The results show that serpentine and iron oxide formed when olivine and orthopyroxene individually reacted with a saline starting solution. Olivine-derived serpentine had a significantly lower FeO content (6.57 ± 1.30 wt.% than primary olivine (9.86 wt.%, whereas orthopyroxene-derived serpentine had a comparable FeO content (6.26 ± 0.58 wt.% to that of primary orthopyroxene (6.24 wt.%. In experiments on peridotite, olivine was replaced by serpentine and iron oxide. However, pyroxene transformed solely to serpentine. After 20 days, olivine-derived serpentine had a FeO content of 8.18 ± 1.56 wt.%, which was significantly higher than that of serpentine produced in olivine-only experiments. By contrast, serpentine after orthopyroxene had a slightly higher FeO content (6.53 ± 1.01 wt.% than primary orthopyroxene. Clinopyroxene-derived serpentine contained a significantly higher FeO content than its parent mineral. After 120 days, the FeO content of olivine-derived serpentine decreased significantly (5.71 ± 0.35 wt.%, whereas the FeO content of orthopyroxene-derived serpentine increased (6.85 ± 0.63 wt.% over the same period. This suggests that iron oxide preferentially formed after olivine serpentinization. Pyroxene in peridotite gained some Fe from olivine during the serpentinization process, which may have led to a decrease in iron oxide production. The correlation between FeO content and SiO2 or Al2O3 content in olivine- and

  20. A tapered serpentine flow field for the anode of micro direct methanol fuel cells (United States)

    Zhang, Yufeng; Zhang, Peng; Yuan, Zhenyu; He, Hong; Zhao, Youran; Liu, Xiaowei


    We develop a self-breathing micro direct methanol fuel cell (μDMFC) characterized by a new anode structure with tapered single serpentine flow fields to improve cell performance. Compared with the conventional single serpentine flow field, this new design enhances the methanol mass transport efficiency and the exhaust resultant (CO2) rate due to the increasing pressure difference between adjacent flow channels. The μDMFCs with two single serpentine flow fields are fabricated using silicon-based micro-electro-mechanical systems (MEMS) technologies and are tested at room temperature. The experimental results reveal that the new tapered single serpentine flow field exhibits a significantly higher peak power density than that of the conventional flow field, demonstrating a substantial increase of 17.9% in mass transport coefficients.

  1. Seawater-derived rare earth element addition to abyssal peridotites during serpentinization (United States)

    Frisby, Carl; Bizimis, Michael; Mallick, Soumen


    Serpentinized abyssal peridotites are evidence for active communication between the Earth's hydrosphere and the upper mantle, where exchange and retention of both major and trace elements occur. Bulk rock Nd isotopes in serpentinized abyssal peridotites imply interaction of seawater with the peridotite. In contrast, the Nd isotopes of clinopyroxenes from serpentinized abyssal peridotites retain their primary magmatic signature. It is currently unclear if, how and where seawater-derived Nd and other REE are being added or exchanged with the mantle peridotite minerals during serpentinization. To remedy this knowledge gap, we present in situ trace and major element concentrations, bulk rock and sequential leaching experiment trace element concentrations as well as Nd, Sr isotope data on refertilized and depleted serpentinized abyssal peridotites from the Southwest Indian Ridge. The secondary serpentine matrix and magnetite veins in these peridotites have elevated LREE concentrations, with variable negative Ce anomalies and large Rb, Sr, Pb and U enrichments that resemble seawater trace element patterns. The LREE concentrations in the serpentine phase are higher than those expected for the primary mantle mineralogy (olivine, orthopyroxene) based on data from relic clinopyroxenes and equilibrium partition coefficients. These data are consistent with seawater-derived REE addition to the peridotite during serpentinization. The bulk rocks have more radiogenic Sr and more unradiogenic Nd isotopes than their clinopyroxene (up to 8 εNd units lower than clinopyroxene). Sequential leaching experiments designed to mobilize secondary carbonates and Fe-oxides show even more unradiogenic Nd isotope ratios in the leachates than the bulk rock and clinopyroxene, approaching seawater compositions (up to 15 εNd units lower than clinopyroxene). Mass balance calculations using trace elements or Nd isotopes suggest that up to 30% of the bulk peridotite Nd budget is of seawater origin and

  2. Experimental investigation of As, Sb and Cs behavior during olivine serpentinization in hydrothermal alkaline systems (United States)

    Lafay, Romain; Montes-Hernandez, German; Janots, Emilie; Munoz, Manuel; Auzende, Anne Line; Gehin, Antoine; Chiriac, Rodica; Proux, Olivier


    While Fluid-Mobile Elements (FMEs) such as B, Sb, Li, As or Cs are particularly concentrated in serpentinites, data on FME fluid-serpentine partitioning, distribution, and sequestration mechanisms are missing. In the present experimental study, the behavior of Sb, As and Cs during San Carlos olivine serpentinization was investigated using accurate mineralogical, geochemical, and spectroscopic characterization. Static-batch experiments were conducted at 200 °C, under saturated vapor pressure (≈1.6 MPa), for initial olivine grain sizes of product content was determined as a function of reaction advancement for the different initial olivine grain sizes investigated. The results confirm that serpentinization products have a high FME uptake capacity with the partitioning coefficient increasing such as CsDp/fl = 1.5-1.6 products, especially brucite. In contrast, mineralogical characterization combined with XAS spectroscopy reveal redox sensitivity for Sb sequestration within serpentine products, depending on the progress of the reaction. When serpentinization is products is observed and is attributed to a reduction of Sb(V) into Sb(III). This stage is characterized by the precipitation of Sb-Ni-rich phases and a lower bulk partitioning coefficient compared to that of the serpentine and brucite assemblage. Antimony reduction appears linked to water reduction accompanying the bulk iron oxidation, as half the initial Fe(II) is oxidized into Fe(III) and incorporated into the serpentine products once the reaction is over. The reduction of Sb implies a decrease of its solubility, but the type of secondary Sb-rich phases identified here might not be representative of natural systems where Sb concentrations are lower. These results bring new insights into the uptake of FME by sorption on serpentine products that may form in hydrothermal environments at low temperatures. FME sequestration here appears to be sensitive to various physicochemical parameters and more particularly

  3. Hajdu-Cheney syndrome associated with serpentine fibulae and polycystic kidney disease

    Energy Technology Data Exchange (ETDEWEB)

    Currarino, Guido [Texas Scottish Rite Hospital, Department of Radiology, Dallas, TX (United States)


    Six patients who presented with craniofacial anomalies, musculoskeletal anomalies including elongated and bowed (serpentine) fibulae, and polycystic kidneys are reported. This association of anomalies is referred to as serpentine fibula polycystic kidney syndrome (SFPKS) and is currently interpreted as a manifestation of Hajdu-Cheney syndrome (HCS). We report a new instance of this association of anomalies and review the clinical and radiographic features of HCS and of the reported cases of SFPKS. (orig.)

  4. Fe-Ni-bearing serpentines from the saprolite horizon of Caribbean Ni-laterite deposits: new insights from thermodynamic calculations (United States)

    Villanova-de-Benavent, Cristina; Domènech, Cristina; Tauler, Esperança; Galí, Salvador; Tassara, Santiago; Proenza, Joaquín A.


    Fe-Ni-bearing serpentine from the saprolite horizon is the main Ni ores in hydrous silicate-type Ni laterites and formed by chemical weathering of partially serpentinized ultramafic rocks under tropical conditions. During lateritization, Mg, Si, and Ni are leached from the surface and transported downwards. Fe2+ is oxidized to Fe3+ and fixed as insoluble Fe-oxyhydroxides (mostly goethite) that incorporate Ni. This Ni is later leached from goethite and incorporated in secondary serpentine and garnierite. As a result, a serpentine-dominated saprolite horizon forms over the ultramafic protolith, overlapped by a Fe-oxyhydroxide-dominated limonite horizon. The serpentine from the protolith (serpentine I) is of hydrothermal origin and yields similar Ni (0.10-0.62 wt.% NiO) and lower Fe (mostly 1.37-5.81 wt.% FeO) concentrations than the primary olivine. In contrast, Fe-Ni-bearing serpentine from the saprolite (serpentine II) shows significantly higher and variable Fe and Ni contents, typically ranging from 2.23 to 15.59 wt.% Fe2O3 and from 1.30 to 7.67 wt.% NiO, suggesting that serpentine get enriched in Fe and Ni under supergene conditions. This study presents detailed mineralogical, textural, and chemical data on this serpentine II, as well as new insights by thermodynamic calculations assuming ideal solution between Fe-, Ni- and Mg-pure serpentines. The aim is to assess if at atmospheric pressure and temperature Fe-Ni-bearing serpentine can be formed by precipitation. Results indicate that the formation of serpentine II under atmospheric pressure and temperature is thermodynamically supported, and pH, Eh, and the equilibrium constant of the reaction are the parameters that affect the results more significantly.

  5. Characteristics of Honey from Serpentine Area in the Eastern Rhodopes Mt., Bulgaria. (United States)

    Atanassova, Juliana; Pavlova, Dolja; Lazarova, Maria; Yurukova, Lilyana


    Honey samples collected during 2007-2010 from serpentine and non-serpentine localities in the Eastern Rhodopes Mt. (Bulgaria) were characterized on the basis of their pollen content by qualitative melissopalynological analysis and physicochemical composition. Water content, pH, electrical conductivity, macroelements-K, Ca, Mg, P, and microelements-As, Cd, Co, Cr, Cu, Fe, Mn, Na, Ni, Pb, and Zn were determined after the Harmonised Methods of the International Honey Commission and ICP-AES method. The results from serpentine honey samples were compared with data from bee pollen collected from the same serpentine area. Different elements have different concentrations in honey from the same botanical type even collected from the same geographical region, same locality, and same beehive but in different vegetation season. The elements Mg, Mn, Ni, and P contribute mostly for separation of the serpentine honey samples based on measured elemental concentrations and performed principal component analysis. The element concentrations were higher in bee pollen and above the permissible limits for the toxic metals Cd and Pb. No specific indicator plant species was found for identification of the geographical origin of serpentine honey in relation to the forage of bees.

  6. The “Serpentine Syndrome” (H. Jenny, 1980: A Proxy for Soil Remediation

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    Claudio Bini


    Full Text Available Serpentine soils have relatively high concentrations of PTEs (Co, Cr, Cu, Fe, Ni but generally low amounts of major nutrients. They often bear a distinctive vegetation, and a frequently-used approach to understanding serpentine ecology and related environmental hazard has been the chemical analysis of soils and plants. In this paper we report past and current studies on serpentine soils and serpentinophytes. The serpentine vegetation differs from the conterminous non-serpentine areas, being often endemic, and showing macroscopic physionomical characters. Similarly, at microscopic level cytomorphological characteristics of the roots and variations in biochemical parameters were recorded in serpentinophytes. Light microscopy observations showed depressed mitotic activity in the meristematic zone, and consequent reduced root growth. The different tolerance mechanisms responsible for plant adaption to high concentrations of PTEs in serpentine soils can be related to the capacity of plants to limit metal uptake and translocation. The majority of serpentinophytes tend to limit metal absorption to roots: the cell wall constitutes a barrier against metal penetration inside plant tissues. Only a few species are able to accumulate metals in their aerial parts, acting a tolerance mechanism to very high metal concentrations. Serpentinophytes, therefore, could represent proxies for plants  used in remediation of metal-contaminated soils and in phytomining as well.

  7. Serpentine dissolution in hydrochloric acid for carbon dioxide sequestration

    Energy Technology Data Exchange (ETDEWEB)

    Amankwah, R.K.; Pickles, C.A. [Queen' s Univ., Kingston, ON (Canada). Dept. of Mining Engineering


    Increased carbon dioxide concentrations in the atmosphere can be attributed to industrialization and the associated combustion of large amounts of fossil fuels. The release of carbon dioxide into the atmosphere causes greenhouse gases, which is expected to have a destabilizing effect on the climate. Several methods have been investigated to reduce the amount of greenhouse gases in the atmosphere, such as improved energy efficiency and conservation programs; utilization of alternative energy sources; and carbon dioxide sequestration. This paper discussed the sequestration of carbon dioxide by minerals as a potential method for reducing the greenhouse gas concentration in the atmosphere. The paper presented a study that involved the dissolution of lizardite, a serpentine mineral, in hydrochloric acid at high pressures in an autoclave. The thermodynamics of the system were examined and experimental data were presented. The solubility of the mineral was shown to be strongly dependent on processing time, acid concentration and pulp density but not strongly affected by stirring or temperature. The paper also discussed the characterization of the reacted samples by thermogravimetric analysis, differential scanning calorimetry, and Fourier transform infrared spectroscopy. The reacted samples were compared to the as-received material. It was concluded that the equilibrium calculations, the kinetic experiments and the characterization of the processed samples indicated that a silica-rich layer formed on the lizardite as the magnesium dissolved, and that this layer hindered further dissolution. 13 refs., 1 tab., 8 figs.

  8. Edaphic factors and plant-insect interactions: direct and indirect effects of serpentine soil on florivores and pollinators. (United States)

    Meindl, George A; Bain, Daniel J; Ashman, Tia-Lynn


    Edaphic factors can lead to differences in plant morphology and tissue chemistry. However, whether these differences result in altered plant-insect interactions for soil-generalist plants is less understood. We present evidence that soil chemistry can alter plant-insect interactions both directly, through chemical composition of plant tissue, and indirectly, through plant morphology, for serpentine-tolerant Mimulus guttatus (Phrymaceae). First, we scored floral display (corolla width, number of open flowers per inflorescence, and inflorescence height), flower chemistry, pollinator visitation and florivory of M. guttatus growing on natural serpentine and non-serpentine soil over 2 years. Second, we conducted a common garden reciprocal soil transplant experiment to isolate the effect of serpentine soil on floral display traits and flower chemistry. And last, we observed arrays of field-collected inflorescences and potted plants to determine the effect of soil environment in the field on pollinator visitation and florivore damage, respectively. For both natural and experimental plants, serpentine soil caused reductions in floral display and directly altered flower tissue chemistry. Plants in natural serpentine populations received fewer pollinator visits and less damage by florivores relative to non-serpentine plants. In experimental arrays, soil environment did not influence pollinator visitation (though larger flowers were visited more frequently), but did alter florivore damage, with serpentine-grown plants receiving less damage. Our results demonstrate that the soil environment can directly and indirectly affect plant-mutualist and plant-antagonist interactions of serpentine-tolerant plants by altering flower chemistry and floral display.

  9. Metagenomic analysis of carbon cycling and biogenic methane formation in terrestrial serpentinizing fluid springs (United States)

    Woycheese, K. M.; Meyer-Dombard, D. R.; Cardace, D.; Arcilla, C. A.; Ono, S.


    The products of serpentinization are proposed to support a hydrogen-driven microbial biosphere in ultrabasic, highly reducing fluids. Shotgun metagenomic analysis of microbial communities collected from terrestrial serpentinizing springs in the Philippines and Turkey suggest that mutualistic relationships may help microbial communities thrive in highly oligotrophic environments. Understanding how these relationships affect production of methane in the deep subsurface is critical to applications such as carbon sequestration and natural gas production. There is conflicting evidence regarding whether methane and C2-C6 alkanes in serpentinizing ecosystems are produced abiogenically or through biotic reactions such as methanogenesis1, 2. While geochemical analysis of methane from serpentinizing ecosystems has previously indicated abiogenic and/or mixed formation3, 4, methanogens have been detected in an increasing number of investigations2. Here, putative metabolisms were identified via assembly and annotation of metagenomic sequence data from the Philippines and Turkey. At both sites, hydrogenotrophic methanogenesis and homoacetogenesis were identified as the principal autotrophic carbon fixation pathways. Heterotrophic acetogenesis and acetoclastic methanogenesis were also detected in sequence data. Other heterotrophic metabolic pathways identified included sulfate reduction, methanotrophy, and biodegradation of aromatic carbon compounds. Many of these metabolic pathways have been shown to be favorable under conditions typical of serpentinizing habitats5. Metagenomic analysis strongly suggests that at least some of the methane originating from these serpentinizing ecosystems may be biologically derived. Ongoing work will further clarify the mechanisms of methane formation by examining the clumped isotopologue ratios of dissolved methane in serpentinizing fluids. 1. Wang et al. (2015). Science. 348. doi: 10.1126/science.aaa4326 2. Kohl et al. (2016). JGR. Biogeosci

  10. Patterns on serpentine shapes elicit visual attention in marmosets (Callithrix jacchus). (United States)

    Wombolt, Jessica R; Caine, Nancy G


    Given the prevalence of threatening snakes in the evolutionary history, and modern-day environments of human and nonhuman primates, sensory, and perceptual abilities that allow for quick detection of, and appropriate response to snakes are likely to have evolved. Many studies have demonstrated that primates recognize snakes faster than other stimuli, and it is suggested that the unique serpentine shape is responsible for its quick detection. However, there are many nonthreatening serpentine shapes in the environment (e.g., vines) that are not threatening; therefore, other cues must be used to distinguish threatening from benign serpentine objects. In two experiments, we systematically evaluated how common marmosets (Callithrix jacchus) visually attend to specific snake-like features. In the first experiment, we examined if skin pattern is a cue that elicits increased visual inspection of serpentine shapes by measuring the amount of time the marmosets looked into a blind before, during, and after presentation of clay models with and without patterns. The marmosets spent the most time looking at the objects, both serpentine and triangle, that were etched with scales, suggesting that something may be uniquely salient about scales in evoking attention. In contrast, they showed relatively little interest in the unpatterned serpentine and control (a triangle) stimuli. In experiment 2, we replicated and extended the results of experiment 1 by adding additional stimulus conditions. We found that patterns on a serpentine shape generated more inspection than those same patterns on a triangle shape. We were unable to confirm that a scaled pattern is unique in its ability to elicit visual interest; the scaled models elicited similar looking times as line and star patterns. Our data provide a foundation for future research to examine how snakes are detected and identified by primates. Am. J. Primatol. 78:928-936, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals

  11. Frictional Constitutive Parameters for Serpentine Mud from South Chamorro Seamount (United States)

    Noda, H.; Shimamoto, T.; Ishii, T.


    The lack of great earthquakes in Izu-Ogasawara and Mariana subduction zones may be associated with low-temperature serpentinite (M. Kasahara, 2003). We have thus started experimental studies on fault constitutive properties of serpentinite gouge, using a biaxial frictional testing machine at Kyoto University. Many conically-shaped serpentine seamounts are developed behind those subduction zones. They are consisted mainly of serpentinite mud with clasts of mantle rocks and high-pressure metamorphic rocks. Previous studies imply that the serpentinite is likely to have formed at depths around 30km. We have used serpentine mud, consisted mainly of chrysotile, in the drill core from South Chamorro Seamount (ODP Leg195). Double shear frictional experiments have been conducted on about 0.3 mm thick gouge at 30 MPa normal stress, at room temperature and under wet conditions (but without pore pressure). A series of velocity-step tests were performed in velocity range from 0.015 to 150 μm/s. Rate-and-state constitutive laws were fit to experimental data, by solving specimen-apparatus interaction numerically searching for the optimum constitutive parameters. Determination of stiffness of the apparatus is essential for accurate estimate of constitutive parameters. Careful measurements have revealed that the total stiffness (9.00×107 N/m) fluctuates by up to about 10 % probably owing to loose alignment of machine elements. This induces errors in constitutive parameters depending on dc}. If dc is in the order of 10 μm or larger, the error in b value is in the order of percent or less. But if the dc is around 1 μm, it becomes tens of percents or larger. The absolute value of frictional coefficient is around 0.2, very low and consistent with that of pure chrysotile (Moore et al., 1997). a- σb value is about 0.005 for velocity steps at 0.015-0.15 μm/s, decreases with increasing slip rate down to about -0.01 for the velocity steps at 15-150 μm/s. It changes from positive to

  12. OmniTread OT-4 serpentine robot: new features and experiments (United States)

    Borenstein, Johann; Hansen, Malik


    Serpentine robots are slender, multi-segmented vehicles designed to provide greater mobility than conventional wheeled or tracked robots. Serpentine robots are thus ideally suited for urban search and rescue, military intelligence gathering, and for surveillance and inspection tasks in hazardous and hard-to-reach environments. One such serpentine robot, developed at the University of Michigan, is the "OmniTread OT-4." The OT-4 comprises seven segments, which are linked to each other by 2-degree-of-freedom joints. The OT-4 can climb over obstacles that are much higher than the robot itself, propel itself inside pipes of different diameters, and traverse even the most difficult terrain, such as rocks or the rubble of a collapsed structure. The foremost and unique design characteristic of the OT-4 is the use of pneumatic bellows to actuate the joints. These bellows allow simultaneous control of position and stiffness for each joint. Controllable stiffness is of crucial importance in serpentine robots, which require stiff joints to cross gaps and compliant joints to conform to rough terrain for effective propulsion. Another unique feature of the OmniTread design is the maximal coverage of all four sides with driven tracks. This design makes the robot indifferent to roll-overs, which are happen frequently when the slender bodies of serpentine robots travel over rugged terrain. This paper describes the OmniTread concept as well as its latest technical features, and an extensive Experiment Results Section documents the abilities of the OT-4.

  13. Mineral characterization of soil type ranker formed on serpentines occurring in southern Belgrade environs Bubanj Potok

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    Cekić Božidar Đ.


    Full Text Available The paper addresses the issue of health risk associated with the presence of chrysotile in the soil type ranker formed on massive serpentines occurring in the area of Bubanj Potok, a settlement located in the southern Belgrade environs, Serbia. Characterization of the ranker soil was conducted by scanning electron microscopy, X-ray diffraction, micro-Raman spectroscopy and transmission 57Fe Mössbauer spectroscopy. Scanning electron microscopy figures showed regular shaped smectite (montmorillonite particles, aggregates of chlorite, and elongated sheets of serpentines minerals antigorite. X-ray diffraction analysis confirmed the presence of detrital mineral quartz polymorph as well as minor amounts of other mineral species. Micro-Raman spectroscopy identified the presence of dominant minerals, such as montmorillonite, kaolinite, muscovite, gypsum, calcite, albite, amphiboles (hornblende/kaersutite and orthoclase. Important polymorph silica modifications of quartz, olivine (forsterite, pyroxene (enstatite/ferrosilite, diopside/hedenbergite, and serpentine (antigorite/lizardite/chrysotile were identified.

  14. Endovascular Treatment of Giant Serpentine Aneurysm of the Middle Cerebral Artery. (United States)

    Jeong, Young Ha; Kim, Jong Yeon; Koo, Youn Moo; Choi, Jong Wook; Whang, Kum; Hu, Chul; Cho, Sung Min


    Giant serpentine aneurysms are uncommon types of aneurysmal disease and have angiographically authentic features. We report a case of a 44-year-old male with headache and seizure. He presented a giant serpentine aneurysm arising from the middle cerebral artery (MCA). It was a large intracranial aneurysm thrombosed as a mass-like lesion while it maintained its outflow drainage into the distal MCA branches. The balloon occlusion test (BOT) was performed to test the tolerance of temporary collateral circulation. Following routine cerebral angiography, we performed an endovascular embolization on the proximal artery of MCA. He was discharged from the hospital with alert mental status and mild Gerstmann syndrome. The short-term follow-up imaging studies showed the decreased mass effect, and the patient presented an improved Gerstmann syndrome. After a careful evaluation of BOT, an endovascular embolization can be one of the powerful therapeutic instruments for giant serpentine aneurysm.

  15. Serpentine Robot Model and Gait Design Using Autodesk Inventor and Simulink SimMechanics

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    Full Text Available The authors introduce gaits of a serpentine robot with linear expansion mechanism where the robot varies its length using joints with three degrees of freedom. The 3D model of the serpentine robot is drawed in Autocad Inventor® and exported to SimMechanics® for straighforward modeling of the kinematics. The gaits are important for robots designed to explore ruins of disasters where the working spaces are very tight. For maximum flexibility of the serpentine robot, we adopted a joint design with three parallel actuators, where the joint is capable of linear movement in the forward axis, and rotational movements around two other axes. The designed linear expansion gaits is calculated for forward movement when the robot is posing straight or turning laterally.

  16. Nickel speciation in several serpentine (ultramafic) topsoils via bulk synchrotron-based techniques

    Energy Technology Data Exchange (ETDEWEB)

    Siebecker, Matthew G.; Chaney, Rufus L.; Sparks, Donald L.


    Serpentine soils have elevated concentrations of trace metals including nickel, cobalt, and chromium compared to non-serpentine soils. Identifying the nickel bearing minerals allows for prediction of potential mobility of nickel. Synchrotron-based techniques can identify the solid-phase chemical forms of nickel with minimal sample treatment. Element concentrations are known to vary among soil particle sizes in serpentine soils. Sonication is a useful method to physically disperse sand, silt and clay particles in soils. Synchrotron-based techniques and sonication were employed to identify nickel species in discrete particle size fractions in several serpentine (ultramafic) topsoils to better understand solid-phase nickel geochemistry. Nickel commonly resided in primary serpentine parent material such as layered-phyllosilicate and chain-inosilicate minerals and was associated with iron oxides. In the clay fractions, nickel was associated with iron oxides and primary serpentine minerals, such as lizardite. Linear combination fitting (LCF) was used to characterize nickel species. Total metal concentration did not correlate with nickel speciation and is not an indicator of the major nickel species in the soil. Differences in soil texture were related to different nickel speciation for several particle size fractionated samples. A discussion on LCF illustrates the importance of choosing standards based not only on statistical methods such as Target Transformation but also on sample mineralogy and particle size. Results from the F-test (Hamilton test), which is an underutilized tool in the literature for LCF in soils, highlight its usefulness to determine the appropriate number of standards to for LCF. EXAFS shell fitting illustrates that destructive interference commonly found for light and heavy elements in layered double hydroxides and in phyllosilicates also can occur in inosilicate minerals, causing similar structural features and leading to false positive results in

  17. Global rates of mantle serpentinization and H2 release at oceanic transform faults (United States)

    Ruepke, Lars; Hasenclever, Joerg


    The cycling of seawater through the ocean floor is the dominant mechanism of biogeochemical exchange between the solid earth and the global ocean. Crustal fluid flow appears to be typically associated with major seafloor structures, and oceanic transform faults (OTF) are one of the most striking yet poorly understood features of the global mid-ocean ridge systems. Fracture zones and transform faults have long been hypothesized to be sites of substantial biogeochemical exchange between the solid Earth and the global ocean. This is particularly interesting with regard to the ocean biome. Deep ocean ecosystems constitute 60% of it but their role in global ocean biogeochemical cycles is much overlooked. There is growing evidence that life is supported by chemosynthesis at hydrothermal vents but also in the crust, and therefore this may be a more abundant process than previously thought. In this context, the serpentine forming interaction between seawater and cold lithospheric mantle rocks is particularly interesting as it is also a mechanism of abiotic hydrogen and methane formation. Interestingly, a quantitative global assessment of mantle serpentinization at oceanic transform faults in the context of the biogeochemical exchange between the seafloor and the global ocean is still largely missing. Here we present the results of a set of 3-D thermo-mechanical model calculations that investigate mantle serpentinization at OTFs for the entire range of globally observed slip rates and fault lengths. These visco-plastic models predict the OTF thermal structure and the location of crustal-scale brittle deformation, which is a prerequisite for mantle serpentinization to occur. The results of these simulations are integrated with information on the global distribution of OTF lengths and slip rates yielding global estimates on mantle serpentinization and associated H2 release. We find that OTFs are potentially sites of intense crustal fluid flow and are in terms of H2 release

  18. Nickel accumulation in leaves, floral organs and rewards varies by serpentine soil affinity. (United States)

    Meindl, George A; Bain, Daniel J; Ashman, Tia-Lynn


    Serpentine soils are edaphically stressful environments that host many endemic plant species. In particular, serpentine soils are high in several heavy metals (e.g. nickel, cobalt and chromium) and these high heavy metal concentrations are thought, in part, to lead to varying levels of plant adaptation and soil affinities (i.e. endemic vs. non-endemic plant species). It is unclear, however, whether serpentine endemics vs. non-endemics differ with respect to heavy metal uptake into either vegetative or reproductive organs. Here, we use nickel as a model to determine whether plant heavy metal uptake varies with the level of endemism in several non-hyperaccumulating species. Under controlled greenhouse conditions, we grew seven plant species from the Brassicaceae family that vary in their degrees of affinity to serpentine soil from low (indifferent) to medium (indicator) and high (endemic) in soil that was nickel supplemented or not. We quantified nickel concentrations in leaves, pistils, anthers, pollen and nectar. While nickel concentrations did not vary across organs or affinities when grown in control soils, under conditions of nickel supplementation endemic species had the lowest tissue concentrations of nickel, particularly when considering leaves and pistils, compared with indifferent/indicator species. Species indifferent to serpentines incorporated higher concentrations of nickel into reproductive organs relative to leaves, but this was not the case for indicator species and endemics where nickel concentration was similar in these organs. Our findings suggest that endemic species possess the ability to limit nickel uptake into above-ground tissues, particularly in reproductive organs where it may interfere with survival and reproduction. Indifferent species accumulated significantly more nickel into reproductive organs compared with leaves, which may limit their reproductive potential relative to endemic species when growing on serpentine soils. Additional

  19. From serpentinization to carbonation: New insights from a CO2 injection experiment (United States)

    Klein, Frieder; McCollom, Thomas M.


    We injected a CO2-rich hydrous fluid of seawater chlorinity into an ongoing, mildly reducing (H2(aq)≈3 mmol/kg) serpentinization experiment at 230 °C and 35 MPa to examine the changes in fluid chemistry and mineralogy during mineral carbonation. The chemistry of 11 fluid samples was measured, speciated, and compared with MgO-SiO2-H2O-CO2 (MSHC) phase equilibria to approximate the reaction pathway from serpentinization to carbonation. Although the overall system was in apparent disequilibrium, the speciated activities of dissolved silica (aSiO2(aq)) and carbon dioxide (aCO2(aq)) evolved roughly along MSHC equilibrium phase boundaries, indicative of 4 distinct mineral assemblages over time: (1) serpentine-brucite (± magnesite) before the injection, to (2) serpentine-talc-magnesite 2 h after the injection, to (3) quartz-magnesite (48 h after injection), and (4) metastable olivine-magnesite (623 h after injection) until the experiment was terminated. Inspection of the solid reaction products revealed the presence of serpentine, magnesite, minor talc, and magnetite, in addition to relict olivine. Although quartz was saturated over a short segment of the experiment, it was not found in the solid reaction products. A marked and rapid change in fluid chemistry suggests that serpentinization ceased and precipitation of magnesite initiated immediately after the injection. A sharp decrease in pH after the injection promoted the dissolution of brucite and olivine, which liberated SiO2(aq) and dissolved Mg. Dissolved Mg was efficiently removed from the solution via magnesite precipitation, whereas the formation of talc was relatively sluggish. This process accounts for an increase in aSiO2(aq) to quartz saturation shortly after the injection of the CO2-rich fluid. Molecular dihydrogen (H2(aq)) was generated during serpentinization of olivine by oxidation of ferrous iron before the injection; however, no additional H2(aq) was generated after the injection. Speciation

  20. Evolution of fracture permeability of ultramafic rocks at hydrothermal conditions: An experimental study on serpentinization reactions (United States)

    Farough, A.; Moore, D. E.; Lockner, D. A.; Lowell, R. P.


    Serpentinization of ultramafic rocks, during which olivine and pyroxene minerals are replaced by serpentine, magnetite, brucite and talc, is associated with hydrothermal activity at slow and ultraslow mid-ocean ridges. Serpentinization reactions affect hydrothermal fluid circulation by changing permeability of the oceanic crust. To advance our understanding of the evolution of permeability accompanying serpentinization reactions, we performed a series of flow-through experiments at a temperature of 260˚C, a confining pressure of 50 MPa, and a pore pressure of 20±2 MPa on cylindrical cores of ultramafic rocks (18 mm in diameter and 23 mm length) containing a single through-going tensile fracture. Pore fluid flow was in one direction and was collected routinely for chemical analysis. A 7.5 mm thick layer of the same rock, crushed and sieved (0.18-1.0 mm) was placed on the inlet end of the sample to produce a reactive heated reservoir for the pore fluid before entering the fracture. Multiple peridotite samples were tested, to investigate the effect of mineral assemblage on fluid-rock interaction and permeability. The initial effective permeability of the samples varied between 10-(15-18)m2, and it decreased by about 2 orders of magnitude in 7-10 days, showing that serpentinization reactions result in an initially rapid decrease in permeability. The best fit equation for the observed rate of change in permeability (k) is in the form of dk/dt=Ae-0.01t, where A is a constant and t is time. This result suggests that the rate of serpentine formation is largely controlled by the initial permeability rather than the properties of the reacting rock. Assuming flow between parallel plates, we find the effective crack width decreases by approximately 2 orders of magnitude during the experiments. The fluid chemistry and mineralogy data support the occurrence of serpentinization reactions. The early peak and monotonic decrease in the concentration of Mg, and Si in pore fluid

  1. Some geophysical and geochemical consequences of slab serpentinization at subduction zones (United States)

    Phipps Morgan, J.; Ruepke, L. H.; Ranero, C.; Hort, M.


    Here we explore the potential impact of slab serpentinization and deserpentinization processes on arc-melting and on water, carbon-dioxide, U, Pb, and noble gas recycling into the deep mantle. We examine the consequences of a scenario in which bend-faulting between the outer rise and trench axis creates the conduits for seawater to reach and react with cold lithospheric mantle to serpentinize it. Water penetration to serpentinize the slab-lithosphere will be inhibited by thick sediments (e.g. Cascades) or thick oceanic crust (subducting oceanic plateaus), while subducting long-offset fracture zones will be especially serpentine-rich because they serpentinized at both the spreading center and subduction zone. If this process occurs, then the incoming lithosphere will typically contain ~500m of altered sediments, ~6 km of partially hydrated oceanic crust, and ~20-55km of partially serpentinized slab mantle. Possible regional geophysical consequences of this scenario are: (1) Fracture Zones preferentially become tears in subducting slabs because they are relatively serpentine rich, thus they deserpentinize more. (2) If so, then their greater deserpentinization should produce greater sub-arc water release which leads to greater arc melting above subducted fracture zones. (3) Regions of little serpentinization will be correlated with flat subduction, lower volumes of slab-water release, and relatively low rates of arc-volcanism. Our thermomechanical modelling implies, depending upon a slab's age and subduction rate, between 30-90% of the slab's chemically bound water is likely to survive sub-arc dehydration to transport its water into the deeper mantle. Possible global geochemical consequences of this scenario are: (1) At current subduction rates, 0.5-1.5 oceans of water would be recycled past the arc-melting region into the deeper mantle during the past Ga. (2) Since 0.3%, 1%, and 3% of the exosphere's Ne, Ar, and Xe are dissolved in the oceans, this implies that at

  2. Igneous and metamorphic rocks of the Serpentine Hot Springs area, Seward Peninsula, Alaska

    Energy Technology Data Exchange (ETDEWEB)

    Hudson, T.


    This report describes the geology of the Serpentine Hot Springs area of the Seward Peninsula, Alaska, emphasizing the petrology, petrography, and mapped relations of lithologic units within a composite, epizonal biotite granite stock and the regionally metamorphosed metasedimentary rocks that surround it. Geologic relations are combined with reconnaissance geochemical data to define mineralized zones and their spatial relations to the granite stock.

  3. Arbuscular mycorrhizal symbiosis alleviates drought stress imposed on Knautia arvensis plants in serpentine soil

    Czech Academy of Sciences Publication Activity Database

    Doubková, Pavla; Vlasáková, E.; Sudová, Radka


    Roč. 370, 1-2 (2013), s. 149-161 ISSN 0032-079X R&D Projects: GA AV ČR KJB600050812 Institutional support: RVO:67985939 Keywords : arbuscular mycorrhizal fungi * drought * serpentine soil Subject RIV: EF - Botanics Impact factor: 3.235, year: 2013

  4. Plants as extreme environments? Ni-resistant bacteria and Ni-hyperaccumulators of serpentine flora.

    NARCIS (Netherlands)

    Mengoni, A.; Schat, H.; Vangronsveld, J.


    During recent years there has been an increasing interest in the bacterial communities occurring in unusual, often extreme, environments. On serpentine outcrops around the world, a high diversity of plant species showing the peculiar features of metal hyperaccumulation is present. These metal

  5. The symbiosis with arbuscular mycorrhizal fungi contributes to plant tolerance to serpentine edaphic stress

    Czech Academy of Sciences Publication Activity Database

    Doubková, Pavla; Suda, Jan; Sudová, Radka


    Roč. 4, č. 1 (2012), s. 56-64 ISSN 0038-0717 R&D Projects: GA AV ČR KJB600050812 Institutional research plan: CEZ:AV0Z60050516 Keywords : serpentine syndrome * arbuscular mycorrhizal fungi * reciprocal transplant experiment Subject RIV: EF - Botanics Impact factor: 3.654, year: 2012

  6. First principles investigation of the structure, elasticity, and vibrational property of the serpentine minerals. (Invited) (United States)

    Tsuchiya, J.; Tsuchiya, T.


    Serpentine is formed by reaction between peridotite and water which is released from hydrous mineral in subducting slab under pressure. Partially serpentinized peridotite may be a significant reservoir for water in the subducted cold slab and is considered to play an important role in subduction zone processes such as generation of arc magmatism. Precise determination of structure, vibrational and elastic properties of serpentine become the basis for understanding the transporting processes of water into deep Earth interior. Here we investigate by first principles calculation, the detailed structures, vibrational and elastic properties of lizardite, chlorite, and antigorite which are major hydrous minerals in the serpentinized peridotite. We found a very sudden softening of the elastic constants at high pressure condition. This anomaly is associated with a slight change in the compressibility of the c axis which corresponds to the layer normal direction. The calculated OH stretching frequencies also increase suddenly associated with the anomaly and these vibrational behaviors are consistent with the previous Raman measurements. Since other hydrous phyllosilicates such as clay minerals, and mica have similar crystal structures to these hydrous minerals, these anomalous softening is also expected in these minerals under pressure. Research supported in part by special coordination funds for promoting science and technology (Supporting Young Researchers with Fixed-term Appointments) and Grants-In-Aid for Scientific Research from the Japan Society for the Promotion of Science (Nos. 21740380, 20103005, and 24740357).

  7. Influence of graphite and serpentine minerals along landslide failure surfaces (United States)

    Alberti, Stefano; Battista Crosta, Giovanni; Wang, Gonghui; Dattola, Giuseppe; Bertolo, Davide


    Landslides and deep-seated gravitational slope deformation (DSGSD) often are concentrated in sedimentary and metasedimentary rocks (e.g. Ambrosi and Crosta, 2006) and in carbonaceous materials (CM), where weaker slip surfaces can be generated more easily, with a behaviour similar to that of fault zone (e.g. Zulauf et al., 1990; Craw, 2002; Oohashi et al., 2011, Nakamura et al., 2015). Among the carbonaceous minerals, graphite (grouped with other silicate sheet minerals) acts as a "solid lubrificant" and plays a key role on frictional properties of the slip surface (Yamasaki et al., 2015). These minerals have one key characteristic in common: the presence of weak bonding along (001) planes. Graphite also has one of the weakest bonding in the crystal structure, and it is characterized by a markedly low coefficient of friction (ca 0.1). A similar behaviour is found in serpentine minerals series and chlorite. We performed these tests on different samples derived from Mont de La Saxe landslide and Chervaz landslide. The first one is located in the upper Aosta Valley, the second in the central part of the Aosta Valley. Both these landslides are characterized by metasedimentary sequences. The undisturbed samples derived by core recovery surveys. We performed a petrographic characterization by XRD (X-Ray Diffraction), XRF (X-Ray Refraction) and SEM (Scansion Electron Microscope) with microprobe in addition to laboratory tests on samples from shear zones. Along these shear zones grains are crushed, their size and shapes are changed and these changes necessarily affect pore-water pressure due to volume change in the shear zone. We performed tests using a dynamic-loading ring-shear apparatus (DPRI-5, Sassa et al., 1997). This apparatus allows to simulate the entire process of failure, from initial static or dynamic loading, through shear failure, pore-pressure changes and possible liquefaction, to large-displacement, steady-state shear movement. It is also possible to

  8. Methane Dynamics in a Tropical Serpentinizing Environment: The Santa Elena Ophiolite, Costa Rica

    Directory of Open Access Journals (Sweden)

    Melitza Crespo-Medina


    Full Text Available Uplifted ultramafic rocks represent an important vector for the transfer of carbon and reducing power from the deep subsurface into the biosphere and potentially support microbial life through serpentinization. This process has a strong influence upon the production of hydrogen and methane, which can be subsequently consumed by microbial communities. The Santa Elena Ophiolite (SEO on the northwestern Pacific coast of Costa Rica comprises ~250 km2 of ultramafic rocks and mafic associations. The climatic conditions, consisting of strongly contrasting wet and dry seasons, make the SEO a unique hydrogeological setting, where water-rock reactions are enhanced by large storm events (up to 200 mm in a single storm. Previous work on hyperalkaline spring fluids collected within the SEO has identified the presence of microorganisms potentially involved in hydrogen, methane, and methanol oxidation (such as Hydrogenophaga, Methylobacterium, and Methylibium spp., respectively, as well as the presence of methanogenic Archaea (such as Methanobacterium. Similar organisms have also been documented at other serpentinizing sites, however their functions have not been confirmed. SEO's hyperalkaline springs have elevated methane concentrations, ranging from 145 to 900 μM, in comparison to the background concentrations (<0.3 μM. The presence and potential activity of microorganisms involved in methane cycling in serpentinization-influenced fluids from different sites within the SEO were investigated using molecular, geochemical, and modeling approaches. These results were combined to elucidate the bioenergetically favorable methane production and/or oxidation reactions in this tropical serpentinizing environment. The hyperalkaline springs at SEO contain a greater proportion of Archaea and methanogens than has been detected in any terrestrial serpentinizing system. Archaea involved in methanogenesis and anaerobic methane oxidation accounted from 40 to 90% of total

  9. Heavy Metal Resistant, Alkalitolerant Bacteria Isolated From Serpentinizing Springs in the Zambales Ophiolite, Philippines (United States)

    Vallalar, B.; Meyer-Dombard, D. R.; Cardace, D.; Arcilla, C. A.


    Serpentinization involves hydrologic alteration of ultramafic mantle rocks containing olivine and pyroxene to produce serpentine minerals. The fluids resulting from this reaction are reduced, extremely depleted in dissolved inorganic carbon, and are highly alkaline with pH values typically exceeding 10. Major byproducts of the serpentinizing reaction include iron oxides, hydrogen, methane, and small amounts of organic molecules that provide chemosynthetic energy for subsurface microbial communities. In addition, weathering of serpentine rocks often produces fluids and sediments that have elevated concentrations of various toxic heavy metals such as chromium, nickel, cobalt, copper, and zinc. Thus, microorganisms inhabiting these unique ecological niches must be adapted to a variety of physicochemical extremes. The purpose of this study is to isolate bacteria that are capable of withstanding extremely high concentrations of multiple heavy metals from serpentine fluid-associated sediments. Fluid and sediment samples for microbial culturing were collected from Manleluag Spring National Park located on the island of Luzon, Philippines. The area is part of the Zambales ophiolite range, and hosts several serpentinizing fluid seeps. Fluid emanating from the source pool of the spring, designated Manleluag 2 (ML2), has a pH of 10.83 and temperature of 34.4 °C. Luria-Bertani agar medium was supplemented with varying concentrations of five trace elements - Cu, Cr, Co, Ni, and Zn. Environmental samples were spread on each of these media and colony forming units were subsequently chosen for isolation. In all, over 20 isolates were obtained from media with concentrations ranging from 25 mg/L - 400 mg/L of each metal. Taxonomic identity of each isolate was determined using 16S rRNA gene sequences. The isolates were then tested for tolerance to alkaline conditions by altering LB medium to pH values of 8, 9, 10, 11, and 12. The majority of strains exhibit growth at the highest p

  10. Serpentinization reactions in peridotite from the Josephine ophiolite: implications for life on Mars (United States)

    Sonzogni, Y.; Treiman, A. H.


    Serpentinization of ocean crustal peridotite, both beneath the seafloor and as ophiolites on land, has been identified as a source of hydrogen that can support microbial activity. The similarity of Mars' crust to terrestrial ocean lithosphere thus suggests that ophiolites may be good analogs to some martian environments where life might have existed and may persist today. However, peridotite-water reactions are poorly understood in detail, and serpentinization is commonly idealized as isovolumetric or isochemical hydration of olivine to form serpentine, brucite, magnetite, and H2 gas. Here, a net-veined serpentinite from the Josephine ophiolite, California, was studied in order to characterize in detail the physical-chemical nature of its serpentinization. The extent of serpentinization in the studied sample is ~60%. Remnants of the original harzburgite include ~30% olivine, ~10% orthopyroxene, and accessory augite and chromite. Two generations of serpentinite veins are present, the distinction between them being in their textures (in SEM imagery); type 1 veins appear striated, while type 2 veins are massive. Both types of veins consist almost entirely of serpentine. Both types contain types of vein was identified as lizardite based on its foliate texture (as shown in SEM images), suggesting that serpentinization occurred at Ttype 1 veins is more magnesian (Mg# 96) than the lizardite in type 2 veins (Mg# 93). Based on the mineral proportions in the serpentinite and original harzburgite and their mineral compositions, this reaction approximates the formation of type 1 serpentine veins: 22.5 Mg1.80Fe0.20SiO4 + 7.5 Mg0.91Fe0.09SiO3 + 31.15 H2O → 15 Mg2.88Fe0.12Si2O5(OH)4 + 1.13 Fe3O4 + 4.13 MgO(aq) + 31.15 H2. This reaction conserves Si and Fe, but is not isovolumetric nor isochemical. Considering that half of the serpentine in our sample is represented by type 1 veins, this reaction results in a 10% volume increase and removal of 10 wt% MgO from the solids by

  11. ) Mold Fluxes (United States)

    Seo, Myung-Duk; Shi, Cheng-Bin; Cho, Jung-Wook; Kim, Seon-Hyo


    The effects of basicity (CaO/SiO2), B2O3, and Li2O addition on the crystallization behaviors of lime-silica-based mold fluxes have been investigated by non-isothermal differential scanning calorimetry (DSC), field emission scanning electron microscopy, X-ray diffraction (XRD), and single hot thermocouple technique. It was found that the crystallization temperature of cuspidine increased with increasing the basicity of mold fluxes. The crystallization of wollastonite was suppressed with increasing the mold flux basicity due to the enhancement of cuspidine crystallization. The addition of B2O3 suppresses the crystallization of mold flux. The crystallization temperature of mold flux decreases with Li2O addition. The size of cuspidine increases, while the number of cuspidine decreases with increasing mold flux basicity. The morphology of cuspidine in mold fluxes with lower basicity is largely dendritic. The dendritic cuspidine in mold fluxes is composed of many fine cuspidine crystals. On the contrary, in mold fluxes with higher basicity, the cuspidine crystals are larger in size with mainly faceted morphology. The crystalline phase evolution was also calculated using a thermodynamic database, and compared with the experimental results determined by DSC and XRD. The results of thermodynamic calculation of crystalline phase formation are in accordance with the results determined by DSC and XRD.

  12. Experimental Studies on Dehydration Embrittlement of Serpentinized Peridotite and Effect of Pressure on Creep of Olivine (United States)

    Xia, Gang

    The origin of intermediate depth earthquakes has been debated for 90 years yet is still under active discussion. These earthquakes are localized in double seismic zones in descending lithosphere; both zones originate very close to oceanic trenches. A leading proposed initiation mechanism for these earthquakes since 1968 has been dehydration embrittlement of serpentine under stress. Despite the considerable evidence favoring this mechanism, a major argument against it has been that the lower seismic zone initiates at ˜40 km depth almost immediately below trenches and there does not appear to be a vehicle to carry water sufficiently deep to hydrate otherwise dry lithosphere. To directly address this problem, an experimental study has been carried out to investigate the minimum amount of serpentine that is required to trigger the dehydration embrittlement instability in serpentinized peridotite at high pressure (1-3 GPa) and temperature (720-750˚C). The results show that embrittlement occurs during dehydration of antigorite (the phase of serpentine stable at elevated pressure) in a wide range of compositions but both nearly dry peridotite and extensively altered peridotite are ductile. Fresh, unaltered, synthetic harzburgite and harzburgite with 4 vol% distributed antigorite are ductile, as are specimens with greater than 65% antigorite. Only compositions between 8 vol% and 65 vol% antigorite develop the instability. We suggest that very small degrees of serpentinization do not release sufficient H 2O to trigger the instability and that extensive serpentinization avoids the instability because soft, ductile, antigorite becomes the interconnected matrix with olivine and pyroxene existing only as isolated crystals. In that case, dehydration simply facilitates flow. These systematics suggest that small amounts of H2O transported down deep normal (bending) faults at trenches are sufficient to enable the instability in the lower seismic zones, thus providing additional

  13. Iron transformations during low temperature alteration of variably serpentinized rocks from the Samail ophiolite, Oman (United States)

    Mayhew, Lisa E.; Ellison, Eric T.; Miller, Hannah M.; Kelemen, Peter B.; Templeton, Alexis S.


    Partially serpentinized peridotites in the Samail ophiolite in the Sultanate of Oman currently undergo low temperature alteration and hydration both at shallow levels, with water recently in contact with the atmosphere, and at depth, with anoxic, reducing fluids. However, it is unclear how changes in the distribution and oxidation state of Fe are driving the production of energy-rich gases such as hydrogen and methane detected in peridotite catchments. We track the Fe transformations in a suite of outcrop samples representing a subset of the spectrum of least to most altered end-members of the Oman peridotites. We use microscale mineralogical and geochemical analyses including QEMSCAN, Raman spectroscopy, synchrotron radiation X-ray fluorescence (XRF) mapping, and electron microprobe wavelength dispersive spectroscopy. The less-altered peridotites possess a diversity of Fe-bearing phases including relict primary minerals (e.g. olivine, pyroxene, chromite) and secondary phases (e.g. serpentine and brucite). Raman spectroscopy and electron microprobe data (Si/(Mg + Fe)) indicate that much of the serpentine is significantly intergrown with brucite on the sub-micron scale. These data also indicate that the Fe content of the brucite ranges from 10 to 20 wt% FeO. The mineral assemblage of the highly reacted rocks is less diverse, dominated by serpentine and carbonate while olivine and brucite are absent. Magnetite is relatively rare and mainly associated with chromite. Goethite and hematite, both Fe(III)-hydroxides, were also identified in the highly altered rocks. Whole rock chemical analyses reflect these mineralogical differences and show that Fe in the partially serpentinized samples is on average more reduced (∼0.40-0.55 Fe3+/FeTotal) than Fe in the highly reacted rocks (∼0.85-0.90 Fe3+/FeTotal). We propose that olivine, brucite, chromite and, perhaps, serpentine in the less-altered peridotites act as reactive phases during low temperature alteration of the Oman

  14. Global rates of mantle serpentinization and H2 production at oceanic transform faults in 3-D geodynamic models (United States)

    Rüpke, Lars H.; Hasenclever, Jörg


    Previous studies have estimated that mantle serpentinization reactions generate H2 at a rate of 1010-1012 mol/yr along the global mid-ocean ridge (MOR) system. Here we present results of 3-D geodynamic simulations that predict rates of additional mantle serpentinization and H2 production at oceanic transform faults (OTF). We find that the extent and rate of mantle serpentinization increases with OTF length and is maximum at intermediate slip rates of 5 to 10 cm/yr. The additional global OTF-related production of H2 is found to be between 6.1 and 10.7 × 1011 mol/yr, which is comparable to the predicted background MOR rate of 4.1-15.0 × 1011 mol H2/yr. This points to oceanic transform faults as potential sites of intense fluid-rock interaction, where chemosynthetic life could be sustained by serpentinization reactions.

  15. Methane Flux (United States)

    U.S. Geological Survey, Department of the Interior — Methane (CH4) flux is the net rate of methane exchange between an ecosystem and the atmosphere. Data of this variable were generated by the USGS LandCarbon project...

  16. Electron beam irradiation induces abnormal development and the stabilization of p53 protein of American serpentine leafminer, Liriomyza trifolii (Burgess) (United States)

    Koo, Hyun-Na; Yun, Seung-Hwan; Yoon, Changmann; Kim, Gil-Hah


    The American serpentine leafminer fly, Liriomyza trifolii (Burgess), is one of the most destructive polyphagous pests worldwide. In this study, we determined electron beam doses for inhibition of normal development of the leaf miner and investigated the effect of electron beam irradiation on DNA damage and p53 stability. Eggs (0-24 h old), larvae (2nd instar), puparia (0-24 h old after pupariation) and adults (24 h after emergence) were irradiated with increasing doses of electron beam irradiation (six levels between 30 and 200 Gy). At 150 Gy, the number of adults that developed from irradiated eggs, larvae and puparia was lower than in the untreated control. Fecundity and egg hatchability decreased depending on the doses applied. Reciprocal crosses between irradiated and unirradiated flies demonstrated that males were more radiotolerant than females. Adult longevity was not affected in all stages. The levels of DNA damage in L. trifolii adults were evaluated using the alkaline comet assay. Our results indicate that electron beam irradiation increased levels of DNA damage in a dose-dependent manner. Moreover, low doses of electron beam irradiation led to the rapid appearance of p53 protein within 6 h; however, it decreased after exposure to high doses (150 Gy and 200 Gy). These results suggest that electron beam irradiation induced not only abnormal development and reproduction but also p53 stability caused by DNA damage in L. trifolii. We conclude that a minimum dose of 150 Gy should be sufficient for female sterilization of L. trifolii.

  17. Weakness of serpentine minerals revealed by friction experiments under low and high temperature conditions. (United States)

    Harbord, C. W. A.; Tesei, T.; De Paola, N.; Collettini, C.; Scarlato, P.; Viti, C.


    Serpentines are important constituents of fault rocks and mélanges in a large variety of tectonic settings, including some major plate-boundary structures such as the San Andreas fault. Many of these structures are considered frictionally weak on geological and geophysical basis (i.e. µDurham University, UK). The sliding strength of lizardite and chrisotile/polygonal (the typical association in retrograde serpentinites and in several natural shear zones) is lower than previously reported (µ<0.2) and scarcely affected by temperature changes for T<200°. Interestingly, these results are in agreement with the fault strength inferred for the central segment of the San Andreas fault where abundant serpentinites are present. Our observations, together with field evidence from natural shear zones, suggest that serpentine-rich faults may significantly contribute to the weakness of major faults throughout the brittle upper crust.

  18. Method for the production of mineral wool and iron from serpentine ore

    Energy Technology Data Exchange (ETDEWEB)

    O' Connor, William K [Albany, OR; Rush, Gilbert E [Scio, OR; Soltau, Glen F [Lebanon, OR


    Magnesium silicate mineral wools having a relatively high liquidus temperature of at least about C. and to methods for the production thereof are provided. The methods of the present invention comprise melting a magnesium silicate feedstock (e.g., comprising a serpentine or olivine ore) having a liquidus temperature of at least about C. to form a molten magnesium silicate, and subsequently fiberizing the molten magnesium silicate to produce a magnesium silicate mineral wool. In one embodiment, the magnesium silicate feedstock contains iron oxide (e.g., up to about 12% by weight). Preferably, the melting is performed in the presence of a reducing agent to produce an iron alloy, which can be separated from the molten ore. Useful magnesium silicate feedstocks include, without limitation, serpentine and olivine ores. Optionally, silicon dioxide can be added to the feedstock to lower the liquidus temperature thereof.

  19. Sliding friction and wear behaviors of surface-coated natural serpentine mineral powders as lubricant additive (United States)

    Zhang, Baosen; Xu, Yi; Gao, Fei; Shi, Peijing; Xu, Binshi; Wu, Yixiong


    This work aims to investigate the friction and wear properties of surface-coated natural serpentine powders (SP) suspended in diesel engine oil using an Optimal SRV oscillating friction and wear tester. The worn surface was characterized by X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) equipped with energy dispersive spectroscopy (EDS). Results indicated that the additives can improve the wear resistance and decrease friction coefficient of carbon steel friction couples. The 0.5 wt% content of serpentine powders is found most efficient in reducing friction and wear at the load of 50 N. The SEM and XPS analysis results demonstrate that a tribofilm forms on the worn surface, which is responsible for the decrease in friction and wear, mainly with iron oxides, silicon oxides, graphite and organic compounds.

  20. Malenco Serpentine: proposed as a candidate for "Global Heritage Stone Resource" designation (United States)

    Primavori, Piero


    The Malenco Serpentine (Serpentine of Val Malenco) is the commercial name of a meta-peridotitic geological formation, Jurassic-Lower Cretaceous in age, entirely restricted to the borders of the valley of the same name (Malenco Valley), and geographically located in Sondrio Province, Lombardy Region, North Italy. Geologically speaking, it is part of an ophiolithic suture zone situated at the contact of the Austroalpine and Penninic nappes of the Alps (Rhaetian sector); petrographically, it is the result of a polymetamorphic (both regional and contact) and polytectonic history, with the development of a paragenesis of antigorite + chrysotile + chlorite + magnetite + diopside + olivine + titanolivine ± chromite ± pyrite ± brucite, and other iron and copper sulphurs. Malenco Serpentine extends over an area of approximately 170 km2, with a thickness ranging from 1 to 2 km. Lithological and mineralogical features allow the recognition of three distinct lythotypes: 1) a strongly foliated Serpentine - called Serpentine-schist of Val Malenco, with a regular and penetrative schistosity, which makes it possible to split the rock into very fine sheets ("pioda"); 2) a massive Serpentine, with no remarkable foliation, called with different commercial names (Green Vittoria, Green Mare, Green Torre S. Maria etc.); 3) A Clorithic schist (Val Malenco Ollare Stone), in turn subdivisible into two main types, depending on the predominance of Chlorite or Talc, and well known for their thermal behaviour and historical utilization for the production of stoves and cooking pots. The stone is quarried and processed since Middle Ages, and used in building and urban décor since 1800. Particularly, the splittable Serpentine has totally characterized - and still characterizes - the typology of the roofs and the urban style of the Malenco Valley architecture. "Pioda" is the name given to the roofing elements; initially used only for the local building, they were processed and transported out

  1. The origin of the serpentine endemic Minuartia laricifolia subsp. ophiolitica by vicariance and competitive exclusion. (United States)

    Moore, Abigail J; Merges, Dominik; Kadereit, Joachim W


    Serpentine soils harbour a unique flora that is rich in endemics. We examined the evolution of serpentine endemism in Minuartia laricifolia, which has two ecologically distinct subspecies with disjunct distributions: subsp. laricifolia on siliceous rocks in the western Alps and eastern Pyrenees and subsp. ophiolitica on serpentine in the northern Apennines. We analysed AFLPs and chloroplast sequences from 30 populations to examine their relationships and how their current distributions and ecologies were influenced by Quaternary climatic changes. Minuartia laricifolia was divided into four groups with a BAPS cluster analysis of the AFLP data, one group consisted only of subsp. ophiolitica, while three groups were found within subsp. laricifolia: Maritime Alps, north-western Alps and central Alps. The same groups were recovered in a neighbour-joining tree, although subsp. ophiolitica was nested within the Maritime Alps group of subsp. laricifolia. Subspecies ophiolitica contained three different chloroplast haplotypes, which were also found in the Maritime Alps group of subsp. laricifolia. Given its high genetic diversity, subsp. ophiolitica appears to have arisen from subsp. laricifolia by vicariance instead of by long-distance dispersal. Genetic and geographic evidence point to the Maritime Alps populations of subsp. laricifolia as the closest relatives of subsp. ophiolitica. We hypothesize that M. laricifolia was also able to grow on nonserpentine rocks in the northern Apennines during glacial periods when the vegetation was more open, but that only the serpentine-adapted populations were able to persist until the present due to their competitive exclusion from more favourable habitats. © 2013 Blackwell Publishing Ltd.

  2. Design Methodology and Experimental Verification of Serpentine/Folded Waveguide TWTs (United States)


    FW), oscillation, serpentine, stopband, traveling -wave tube (TWT), vacuum electronics. I. INTRODUCTION DEVELOPMENT of high-power broadband vacuum elec...tron devices (VEDs) beyond Ka-band using conventional coupled-cavity and helix traveling -wave tube (TWT) RF cir- cuit fabrication techniques is...between the two positions is simply ks times the relative distance along the waveguide axis. However, from the beam–wave interaction standpoint, the

  3. Decoupling of Serpentinization and Prehnitization in Lower East Pacific Rise Crust at Hess Dee (United States)

    Deasy, R. T.; Wintsch, R. P.; Meyer, R.; Bish, D. L.; Gasaway, C.; Heimdal, T.


    Our down-hole mineralogical and geochemical analyses from the East Pacific Rise fast-spreading lower oceanic crust indicate that alteration of olivine to serpentine and of plagioclase to prehnite were independent, and neither alone monitors the total "alteration." The results are based on representative channel sub-samples recovered from every Hole J core during IODP Expedition 345 to the Hess Deep tectonic window. Samples have been analyzed for trace element, Sr isotopic, and quantitative mineralogical compositions (the latter by Rietveld refinement using X-ray diffraction data). Hole J is the most representative rock succession drilled at the Hess Deep as it penetrated the two principle plutonic lithologies: an upper gabbro and a lower troctolite. Units are significantly distinguished by XRD modal mineralogy and trace element abundances. The more heterogeneous gabbro contains 23-32 wt% clinopyroxene (cpx), 34-54 wt% plagioclase (plag), and <4 wt% olivine (ol). The troctolite contains 3-11% cpx, 14-36% plag, and ≤6% ol. Alteration minerals comprise together 18-31% in the gabbro versus 55-80% of the troctolite. The most abundant alteration products are prehnite and chlorite. Gabbro samples with lowest abundances of alteration minerals (18-20 wt%) preserve 87Sr/86Sr ratios (0.70275-0.7028) consistent with unaltered mantle. The abundance of plag in the gabbro, the major host for Sr, suggests retention of mantle Sr isotopic compositions there is due to the large reservoir of magmatic Sr. 87Sr/86Sr ratios of 0.70300-0.70342 in the troctolite samples indicate seawater interaction, even where olivine is most abundant, and serpentine is at or below the ~1% detection limit by XRD. Significant alteration of the deep crust by seawater thus predates the first appearance of serpentine. These data suggest that the timing and operation of prehnite- and serpentine-producing alteration reactions are independent.

  4. An environmental survey of Serpentine Hot Springs: Geology, hydrology, geochemistry, and microbiology (United States)

    Nordstrom, D. Kirk; Hasselbach, Linda; Ingebritsen, Steven E.; Skorupa, Dana; McCleskey, R. Blaine; McDermott, Timothy R.


    Serpentine Hot Springs is the most visited site in the Bering Land Bridge National Preserve. The hot springs have traditionally been used by the Native people of the Seward Peninsula for religious, medicinal and spiritual purposes and continue to be used in many of the same ways by Native people today. The hot springs are also popular with non-Native users from Nome and other communities, recreational users and pilots from out of the area, and hunters and hikers.

  5. Analysis of Passive Mixing in a Serpentine Microchannel with Sinusoidal Side Walls

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    Muhammad Usman Javaid


    Full Text Available Sample mixing is difficult in microfluidic devices because of laminar flow. Micromixers are designed to ensure the optimal use of miniaturized devices. The present study aims to design a chaotic-advection-based passive micromixer with enhanced mixing efficiency. A serpentine-shaped microchannel with sinusoidal side walls was designed, and three cases, with amplitude to wavelength (A/λ ratios of 0.1, 0.15, and 0.2 were investigated. Numerical simulations were conducted using the Navier–Stokes equations, to determine the flow field. The flow was then coupled with the convection–diffusion equation to obtain the species concentration distribution. The mixing performance of sinusoidal walled channels was compared with that of a simple serpentine channel for Reynolds numbers ranging from 0.1 to 50. Secondary flows were observed at high Reynolds numbers that mixed the fluid streams. These flows were dominant in the proposed sinusoidal walled channels, thereby showing better mixing performance than the simple serpentine channel at similar or less mixing cost. Higher mixing efficiency was obtained by increasing the A/λ ratio.

  6. Combined endophytic inoculants enhance nickel phytoextraction from serpentine soil in the hyperaccumulator Noccaea caerulescens

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    Giovanna eVisioli


    Full Text Available This study assesses the effects of specific bacterial endophytes on the phytoextraction capacity of the Ni-hyperaccumulator Noccaea caerulescens, spontaneously growing in a serpentine soil environment. Five metal-tolerant endophytes had already been selected for their high Ni tolerance (6 mM and plant growth promoting ability. Here we demonstrate that individual bacterial inoculation is ineffective in enhancing Ni translocation and growth of N. caerulescens in serpentine soil, except for specific strains Ncr-1 and Ncr-8, belonging to the Arthrobacter and Microbacterium genera, which showed the highest IAA production and ACC-deaminase activity. Ncr-1 and Ncr-8 co-inoculation was even more efficient in promoting plant growth, soil Ni removal and translocation of Ni, together with that of Fe, Co and Cu. Bacteria of both strains densely colonised the root surfaces and intercellular spaces of leaf epidermal tissue. These two bacterial strains also turned out to stimulate root length, shoot biomass and Ni uptake in Arabidopsis thaliana grown in MS agar medium supplemented with Ni. It is concluded that adaptation of N. caerulescens in highly Ni-contaminated serpentine soil can be enhanced by an integrated community of bacterial endophytes rather than by single strains; of the former, Arthrobacter and Microbacterium may be useful candidates for future phytoremediation trials

  7. Numerical Analysis Of Mixing Under Low And High Frequency Pulsations At Serpentine Micromixers

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    Malecha Ziemowit M.


    Full Text Available The numerical investigation of the mixing process in complex geometry micromixers, as a function of various inlet conditions and various micromixer vibrations, was performed. The examined devices were two-dimensional (2D and three-dimensional (3D types of serpentine micromixers with two inlets. Entering fluids were perturbed with a wide range of the frequency (0 - 50 Hz of pulsations. Additionally, mixing fluids also entered in the same or opposite phase of pulsations. The performed numerical calculations were 3D to capture the proximity of all the walls, which has a substantial influence on microchannel flow. The geometry of the 3D type serpentine micromixer corresponded to the physically existing device, characterised by excellent mixing properties but also a challenging production process (Malecha et al., 2009. It was shown that low-frequency perturbations could improve the average mixing efficiency of the 2D micromixer by only about 2% and additionally led to a disadvantageously non-uniform mixture quality in time. It was also shown that high-frequency mixing could level these fluctuations and more significantly improve the mixing quality. In the second part of the paper a faster and simplified method of evaluation of mixing quality was introduced. This method was based on calculating the length of the contact interface between mixing fluids. It was used to evaluate the 2D type serpentine micromixer performance under various types of vibrations and under a wide range of vibration frequencies.

  8. Formation and transformations of Fe-rich serpentines by asteroidal aqueous alteration processes: A nanoscale study of the Murray chondrite (United States)

    Elmaleh, Agnès; Bourdelle, Franck; Caste, Florent; Benzerara, Karim; Leroux, Hugues; Devouard, Bertrand


    Fe-rich serpentines are an abundant product of the early aqueous alteration events that affected the parent bodies of CM carbonaceous chondrites. Alteration assemblages in these meteorites show a large chemical variability and although water-rock interactions occurred under anoxic conditions, serpentines contain high amounts of ferric iron. To date very few studies have documented Fe valence variations in alteration assemblages of carbonaceous chondrites, limiting the understanding of the oxidation mechanisms. Here, we report results from a nanoscale study of a calcium-aluminum-rich inclusion (CAI) from the Murray chondrite, in which alteration resulted in Fe import and Ca export by the fluid phase and in massive Fe-rich serpentines formation. We combined scanning and transmission electron microscopies and scanning transmission X-ray microscopy for characterizing the crystal chemistry of Fe-serpentines. We used reference minerals with known crystallographic orientations to quantify the Fe valence state in Fe-rich serpentines using X-ray absorption spectroscopy at the Fe L2,3-edges, yielding a robust methodology that would prove valuable for studying oxidation processes in other terrestrial or extra-terrestrial cases of serpentinization. We suggest that aqueous Fe2+ was transported to the initially Fe-depleted CAI, where local changes in pH conditions, and possibly mineral catalysis by spinel promoted the partial oxidation of Fe2+ into Fe3+ by water and the formation of Fe-rich serpentines close to the cronstedtite endmember. Such mechanisms produce H2, which opens interesting perspectives as hydrogen may have reacted with carbon species, or escaped and yield increasingly oxidizing conditions in the parent asteroid. From the results of this nanoscale study, we also propose transformations of the initial cronstedtite, destabilized by later input of Al- and Mg-rich solutions, leading to Fe2+ leaching from serpentines, as well as to random serpentine

  9. Micro-scale investigation of carbonation process in partially serpentinized peridotites (United States)

    Andreani, M.; Menez, B.; Delacour, A.; Pasini, V.; Auzende, A. L.; Brunelli, D.


    The carbonation of ultramafic rocks is, theoretically, the most efficient reaction to trap CO2 irreversibly in the form of solid carbonates, as predicted by equilibrium thermodynamic calculations. However, the success of industrial or natural carbonation in large ultramafic aquifers or oceanic ultramafic exposures does not only rely on the thermodynamic conditions of chemical reactions, but also on their feedback effects on the reactive surface area and on the local porosity and permeability. In addition, side processes like serpentinization, redox reactions, abiotic catalytic effects, and biological activity, can be expected in such complex natural system. Their occurrence and implications on carbon speciation and carbon transfers during hydrothermal alteration of oceanic peridotites have not been explored yet and requires detailed study of natural and/or experimental carbonation zones. We have combined petrographic and electron microscopy with SIMS, Raman and FTIR microspectroscopy on partially serpentinized peridotites drilled during the IODP leg 304 (30°N, MAR) in order to characterize the mechanisms of peridotite carbonation at the fluid-mineral interface and identify the associated speciation of carbon (inorganic and organic carbon occurrences). We present first results on zones located close to talc-tremolite sheared veins in holes 1309B and D. Associations of carbonates, porous phyllosilicates and oxides are observed in close vicinity of relict olivines that underwent a previous stage of serpentinization. The olivine-carbonate interface is nanoporous which facilitates mass transfer between fluid and mineral. The phyllosilicate identified as saponite results from the metasomatic replacement, during the carbonation stage, of previously formed serpentine. These observations do not favour reaction-induced cracking but rather a transfer-controlled process in an open system. Among the submicrometric dark clusters widely-distributed in saponite and in serpentine

  10. Using MicroFTIR to Map Mineral Distributions in Serpentinizing Systems (United States)

    Johnson, A.; Kubo, M. D.; Cardace, D.


    Serpentinization, the water-rock reaction forming serpentine mineral assemblages from ultramafic precursors, can co-occur with the production of hydrogen, methane, and diverse organic compounds (McCollom and Seewald, 2013), evolving water appropriate for carbonate precipitation, including in ophiolite groundwater flow systems and travertine-producing seeps/springs. Serpentinization is regarded as a geologic process important to the sustainability of the deep biosphere (Schrenk et al., 2013) and the origin of life (Schulte et al., 2006). In this study, we manually polished wafers of ultramafic rocks/associated minerals (serpentinite, peridotite, pyroxenite, dunite; olivine, diopside, serpentine, magnetite), and travertine/constituent minerals (carbonate crusts; calcite, dolomite), and observed mineral boundaries and interfaces using µFTIR analysis in reflection mode. We used a Thermo Nicolet iS50 FTIR spectrometer coupled with a Continuum IR microscope to map minerals/boundaries. We identify, confirm, and document FTIR wavenumber regions linked to serpentinite- and travertine-associated minerals by referencing IR spectra (RRUFF) and aligning with x-ray diffraction. The ultramafic and carbonate samples are from the following field localities: McLaughlin Natural Reserve - a UC research reserve, Lower Lake, CA; Zambales, PH; Ontario, CA; Yellow Dog, MI; Taskesti, TK; Twin Sisters Range, WA; Sharon, MA; Klamath Mountains, CA; Dun Mountain, NZ; and Sussex County, NJ. Our goals are to provide comprehensive µFTIR characterization of mineral profiles important in serpentinites and related rocks, and evaluate the resolving power of µFTIR for the detection of mineral-encapsulated, residual organic compounds from biological activity. We report on µFTIR data for naturally occurring ultramafics and travertines and also estimate the limit of detection for cell membrane components in mineral matrices, impregnating increasing mass proportions of xanthan gum in a peridotite sand

  11. Metamorphic assemblages and the direction of flow of metamorphic fluids in four instances of serpentinization (United States)

    Barnes, I.; Rapp, J.B.; O'Neil, J.R.; Sheppard, R.A.; Gude, A.J.


    Fluids related to Serpentinization are of at least three types. The first reported (Barnes and O'Neil, 1969) is a fluid of local meteoric origin, the chemical and thermodynamic properties of which are entirely controlled by olivine, orthopyroxene, brucite, and serpentine reactions. It is a Ca+2-OH-1 type and is shown experimentally to be capable of reacting with albite to yield calcium hydroxy silicates. Rodingites may form where the Ca+2-OH-1 type waters flow across the ultramafic contact and react with siliceous country rock. The second type of fluid has its chemical composition largely controlled before it enters the ultramafic rocks, but reactions within the ultramafic rocks fix the thermodynamic properties by reactions of orthopyroxene, olivine, calcite, brucite, and serpentine. The precipitation of brucite from this fluid clearly shows that fluid flow allows reaction products to be deposited at a distance from the point of solution. Thus, textural evidence for volume relations during Serpentinization may not be valid. The third type of fluid has its chemical properties fixed in part before the reactions with ultramafic rocks, in part by the reactions of orthopyroxene, olivine, and serpentine and in part by reactions with siliceous country rock at the contact. The reactions of the ultramafic rock and country rock with the fluid must be contemporaneous and require flow to be along the contact. This third type of fluid is grossly supersaturated with talc and tremolite, both found along the contact. The occurrence of magadiite, kenyaite, mountainite, and rhodesite along the contact is probably due to a late stage low-temperature reaction of fluids of the same thermodynamic properties as those that formed the talc and tremolite at higher temperatures. Oxygen isotope analyses of some of these minerals supports this conclusion. Rodingites form from Ca+2-rich fluids flowing across the contact; talc and tremolite form from silica-rich fluids flowing along the contact

  12. Analytical and numerical study on cooling flow field designs performance of PEM fuel cell with variable heat flux (United States)

    Afshari, Ebrahim; Ziaei-Rad, Masoud; Jahantigh, Nabi


    In PEM fuel cells, during electrochemical generation of electricity more than half of the chemical energy of hydrogen is converted to heat. This heat of reactions, if not exhausted properly, would impair the performance and durability of the cell. In general, large scale PEM fuel cells are cooled by liquid water that circulates through coolant flow channels formed in bipolar plates or in dedicated cooling plates. In this paper, a numerical method has been presented to study cooling and temperature distribution of a polymer membrane fuel cell stack. The heat flux on the cooling plate is variable. A three-dimensional model of fluid flow and heat transfer in cooling plates with 15 cm × 15 cm square area is considered and the performances of four different coolant flow field designs, parallel field and serpentine fields are compared in terms of maximum surface temperature, temperature uniformity and pressure drop characteristics. By comparing the results in two cases, the constant and variable heat flux, it is observed that applying constant heat flux instead of variable heat flux which is actually occurring in the fuel cells is not an accurate assumption. The numerical results indicated that the straight flow field model has temperature uniformity index and almost the same temperature difference with the serpentine models, while its pressure drop is less than all of the serpentine models. Another important advantage of this model is the much easier design and building than the spiral models.

  13. Composition, ecology and conservation of the south-Iberian serpentine flora in the context of the Mediterranean basin

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    Pérez-Latorre, Andrés V.


    Full Text Available Peridotite outcrops have special lithological (serpentine and soil characteristics; they also support an unique flora and vegetation “that clearly differ from that of other soil types. One of the most important peridotite outcrops in the Western Mediterranean Basin is located in Sierra Bermeja (Andalusia, Spain. The establishment of a complete ecological-floristic checklist of serpentinophytes in this area, and a comparison with other serpentine-endemic floras in the Mediterranean Basin, is essential for the assessment, management and conservation of these special areas. The recognition of serpentinophytes was made following six criteria used for floras inhabiting special substrata,. The list of species exclusively or partially found on peridotite comprises 27 taxa with a variable degree of serpentinophily: obligate serpentinophytes (obligate endemics, preferential serpentinophytes (populations located mainly on serpentine and subserpentinophytes (with some populations located on magnesium-rich substrata. As observed in other Mediterranean outcrops, the number of obligate serpentinophytes increases with the area of the outcrop, and the genera Alyssum, Arenaria, Armeria, Centaurea and Silene were the most frequent. Most of the studied serpentinophytes, except for a few xerothermophilous taxa, present a wide bioclimatic (altitudinal range and grow in shrublands and pastures in rocky places with shallow soils. As many as 56% of the serpentinophytes are threatened and, among obligate serpentinophytes, 45% are categorized as critically endangered or endangered, emphasizing the need for urgent conservation measures on the species and their habitats Based on this checklist, more detailed studies may focus on serpentinophytes for their particular physiology, adaptive traits, functional types, phenology and applications.Las peridotitas muestran especiales características litológicas (serpentinas y edáficas; lo que condiciona una flora y vegetaci

  14. Seawater storage and element transfer associated with mantle serpentinization in magma-poor rifted margins: A quantitative approach (United States)

    Pinto, Victor Hugo G.; Manatschal, Gianreto; Karpoff, Anne Marie; Ulrich, Marc; Viana, Adriano R.


    Continental breakup in magma-poor rifted margins can develop, in some instances, after the formation of a wide exhumed domain that can be several hundreds of km wide. As exhumation of the continental mantle occurs serpentinization, due to seawater circulation, can extend as far down as 5-6 km, as observed in refraction seismic data. The impact caused by the process of serpentinization within the evolving ocean may have the potential to change: (i) seawater chemistry; (ii) sustain the evolution of primitive life; (iii) control depositional environments; and (iv) form weak zones preferentially used during the formation, reactivation and subduction of distal rifted margins. Based on geological observations, and geophysical and geochemical data from present-day and fossil zones of exhumed continental mantle, we present a first-order quantification showing that approximately 0.380 km3 of water per km2 can be stored in the mantle. Using simple methods, it can be shown that serpentinization may account for a significant loss of Si, Mg, Fe, Mn, Ca, Ni and Cr during serpentinization of mantle rocks. In particular during latest stages of rifting, when basins are often restricted and seaways are not yet connected, exhumation and the serpentinization of large areas of continental mantle may result in a major transfer of elements between the main Earth reservoirs, such as the mantle and seawater.

  15. Channel aspect ratio effect for serpentine proton exchange membrane fuel cell: Role of sub-rib convection (United States)

    Wang, Xiao-Dong; Duan, Yuan-Yuan; Yan, Wei-Mon; Lee, Duu-Jong; Su, Ay; Chi, Pei-Hung

    A complete three-dimensional, two-phase, non-isothermal model for proton exchange membrane (PEM) fuel cells was used to investigate the effect of the sub-rib convection on the performances for the single and triple serpentine flow fields at various channel aspect ratios and different thermal constraints. The occurrence of sub-rib convection, which is affected by the serpentine flow field, significantly influences the cell performance if the oxygen supply or membrane moisture content was limited. For single serpentine flow field in which sub-rib convection presents under all ribs, changing channel aspect ratio has minimal effects on cell performance since the oxygen supply is sufficient. For triple serpentine flow field or for serpentine cell with poor external heat loss, owing to limited sub-rib convection or to low membrane moisture content, decrease in channel aspect ratio significantly enhances cell performance. Blocking up the sub-rib convection markedly reduces cell performance. Flow field design for PEM fuel cell should take into consideration the effects of sub-rib convection flow on cell performance.

  16. Abiotic vs biological sources and fates of organic compounds in a low temperature continental serpentinizing system (United States)

    Robinson, K.; Noble, S. M.; Shock, E.


    Serpentinization is likely the most common water-rock reaction in our solar system. During this process ultramafic silicates are hydrated, a calcium hydroxide solution is formed, and H2O is reduced to H2 coupled to the oxidation of Fe2+ to Fe3+. The resulting hyper-alkaline, reduced conditions generate thermodynamic drives for numerous carbon compound reactions, including the precipitation of various carbonate minerals and the reduction of inorganic carbonate to organic carbon. Testing the extent to which these thermodynamic drives lead to observable results led to the present study of the flow and transformations of carbon through the active continental serpentinizing system at the Samail Ophiolite in the Sultanate of Oman. Water samples were collected from shallow groundwater (representing system input), hyper-alkaline seeps (system output), boreholes (system intermediate), and surface fluid mixing zones, and analyzed for concentrations of dissolved inorganic carbon (DIC + δ13C), organic carbon (+ δ13C), formate, acetate, H2, methane (+ δ13C), ethane, and an accompanying suite of other geochemical solutes. These analyses indicate that the vast majority of DIC in these serpentinizing fluids precipitates in the subsurface as carbonate minerals; however, a significant amount of DIC is converted into organic acids and light hydrocarbons and expelled at the surface in hyper-alkaline seeps. Based on thermodynamic calculations, it seems most likely that formate last equilibrated with dolomite (CaMg[CO3]2) in the subsurface, acetate last equilibrated with calcite (CaCO3) near the surface, and methane and ethane last equilibrated in a distinct carbon-limited region of the subsurface. As for the fates of these compounds, energetic calculations reveal that a combination of oxidative, reductive, and fermentative metabolisms are thermodynamically favorable. Indeed, δ13C trends record microbial methane oxidation at the surface and cannot rule out methane as biologically

  17. Ecological Features of Spontaneous Vascular Flora of Serpentine Post-Mining Sites in Lower Silesia

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    Kasowska Dorota


    Full Text Available The aim of this study was to determine the ecological characteristics of vascular plants colonizing serpentine mining waste dumps and quarries in Lower Silesia. The investigated flora was analyzed with regard to species composition, geographical-historical status, life forms, as well as selected ecological factors, such as light and trophic preferences, soil moisture and reaction, value of resistance to increased heavy metals content in the soil, seed dispersal modes and occurrence of mycorrhiza. There were 113 species of vascular plants, belonging to 28 families, found on seven sites in the study. The most numerous families were Asteraceae, Poaceae, Fabaceae and Caryophyllaceae. Only 13% of all plants recorded occurred on at least five of the study sites. The most numerous were species related to dry grassland communities, particularly of the Festuco-Brometea class, which included taxa endangered in the region of Lower Silesia: Avenula pratensis, Salvia pratensis, Festuca valesiaca. Apophytes dominated in the flora of the investigated communities. Hemicryptophytes were the most numerous group and therophytes were also abundant. The serpentine mining waste dumps and querries hosted heliophilous species which prefer mesic or dry habitats moderately poor in nutrients, featuring neutral soil reaction. On two study sites 30% of the flora composition consisted of species that tolerate an increased content of heavy metals in the soil. Anemochoric species were the most numerous with regard to types of seed dispersal. Species with an arbuscular type of mycorrhiza were definitely dominant in the flora of all the study sites, however, the number of nonmycorrhizal species was also relatively high. It was suggested that both the specific characteristics of the habitats from serpentine mining and the vegetation of adjacent areas had a major impact on the flora composition of the communities in the investigated sites.

  18. New insight on Li and B isotope fractionation during serpentinization derived from batch reaction investigations (United States)

    Hansen, Christian T.; Meixner, Anette; Kasemann, Simone A.; Bach, Wolfgang


    Multiple batch experiments (100 °C, 200 °C; 40 MPa) were conducted, using Dickson-type reactors, to investigate Li and B partitioning and isotope fractionation between rock and water during serpentinization. We reacted fresh olivine (5 g; Fo90; [B] = saline solutions (NaB(OH)4(aq) and B(OH)3Cl-) as well as variable B fixation and fractionation for different serpentinization product minerals (brucite, chrysotile). Breakdown of the Li-rich olivine and limited Li incorporation into product mineral phases resulted in an overall lower Li content of the final solid phase assemblage at 200 °C ([Li]final_200 °C = 0.77 μg/g; DS/FLi200 °C = 1.58). First order changes in Li isotopic compositions were defined by mixing of two isotopically distinct sources i.e. the fresh olivine and the fluid rather than by equilibrium isotope fraction. At 200 °C primary olivine is dissolved, releasing its Li budget into the fluid which shifts towards a lower δ7LiF of +38.62‰. Newly formed serpentine minerals (δ7LiS = +30.58‰) incorporate fluid derived Li with a minor preference of the 6Li isotope. At 100 °C Li enrichment of secondary phases exceeded Li release by olivine breakdown ([Li]final_100 °C = 2.10 μg/g; DS/FLi100 °C = 11.3) and it was accompanied by preferential incorporation of heavier 7Li isotope that might be due to incorporation of a 7Li enriched fluid fraction into chrysotile nanotubes.

  19. Serpentine endophytic bacterium Pseudomonas azotoformans ASS1 accelerates phytoremediation of soil metals under drought stress. (United States)

    Ma, Ying; Rajkumar, Mani; Moreno, António; Zhang, Chang; Freitas, Helena


    This study evaluates the potential of serpentine endophytic bacterium to foster phytoremediation efficiency of Trifolium arvense grown on multi-metal (Cu, Zn and Ni) contaminated soils under drought stress. A drought resistant endophytic bacterial strain ASS1 isolated from the leaves of Alyssum serpyllifolium grown in serpentine soils was identified as Pseudomonas azotoformans based on biochemical tests and partial 16S rRNA gene sequencing. P. azotoformans ASS1 possessed abiotic stress resistance (heavy metals, drought, salinity, antibiotics and extreme temperature) and plant growth promoting (PGP) properties (phosphate solubilization, nitrogen fixation, production of 1-aminocyclopropane-1-carboxylate deaminase, siderophore and ammonia). Inoculation of T. arvense with ASS1 considerably increased the plant biomass and leaf relative water content in both roll towel assay and pot experiments in the absence and presence of drought stress (DS). In the pot experiments, ASS1 greatly enhanced chlorophyll content, catalase, peroxidase, superoxide dismutase activities, and proline content (only in the absence of drought) in plant leaves, whereas they decreased the concentrations of malondialdehyde. Irrespective of water stress, ASS1 significantly improved accumulation, total removal, bio-concentration factor and biological accumulation coefficient of metals (Cu, Zn and Ni), while decreased translocation factors of Cu. The effective colonization and survival in the rhizosphere and tissue interior assured improved plant growth and successful metal phytoremediation under DS. These results demonstrate the potential of serpentine endophytic bacterium ASS1 for protecting plants against abiotic stresses and helping plants to thrive in semiarid ecosystems and accelerate phytoremediation process in metal polluted soils. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. From elementary flux modes to elementary flux vectors: Metabolic pathway analysis with arbitrary linear flux constraints (United States)

    Klamt, Steffen; Gerstl, Matthias P.; Jungreuthmayer, Christian; Mahadevan, Radhakrishnan; Müller, Stefan


    Elementary flux modes (EFMs) emerged as a formal concept to describe metabolic pathways and have become an established tool for constraint-based modeling and metabolic network analysis. EFMs are characteristic (support-minimal) vectors of the flux cone that contains all feasible steady-state flux vectors of a given metabolic network. EFMs account for (homogeneous) linear constraints arising from reaction irreversibilities and the assumption of steady state; however, other (inhomogeneous) linear constraints, such as minimal and maximal reaction rates frequently used by other constraint-based techniques (such as flux balance analysis [FBA]), cannot be directly integrated. These additional constraints further restrict the space of feasible flux vectors and turn the flux cone into a general flux polyhedron in which the concept of EFMs is not directly applicable anymore. For this reason, there has been a conceptual gap between EFM-based (pathway) analysis methods and linear optimization (FBA) techniques, as they operate on different geometric objects. One approach to overcome these limitations was proposed ten years ago and is based on the concept of elementary flux vectors (EFVs). Only recently has the community started to recognize the potential of EFVs for metabolic network analysis. In fact, EFVs exactly represent the conceptual development required to generalize the idea of EFMs from flux cones to flux polyhedra. This work aims to present a concise theoretical and practical introduction to EFVs that is accessible to a broad audience. We highlight the close relationship between EFMs and EFVs and demonstrate that almost all applications of EFMs (in flux cones) are possible for EFVs (in flux polyhedra) as well. In fact, certain properties can only be studied with EFVs. Thus, we conclude that EFVs provide a powerful and unifying framework for constraint-based modeling of metabolic networks. PMID:28406903

  1. Electron beam irradiation induces abnormal development and the stabilization of p53 protein of American serpentine leafminer, Liriomyza trifolii (Burgess)

    Energy Technology Data Exchange (ETDEWEB)

    Koo, Hyun-Na; Yun, Seung-Hwan; Yoon, Changmann [Department of Plant Medicine, College of Agriculture, Life and Environment Sciences, Chungbuk National University, Cheongju 361-763 (Korea, Republic of); Kim, Gil-Hah, E-mail: [Department of Plant Medicine, College of Agriculture, Life and Environment Sciences, Chungbuk National University, Cheongju 361-763 (Korea, Republic of)


    The American serpentine leafminer fly, Liriomyza trifolii (Burgess), is one of the most destructive polyphagous pests worldwide. In this study, we determined electron beam doses for inhibition of normal development of the leaf miner and investigated the effect of electron beam irradiation on DNA damage and p53 stability. Eggs (0-24 h old), larvae (2nd instar), puparia (0-24 h old after pupariation) and adults (24 h after emergence) were irradiated with increasing doses of electron beam irradiation (six levels between 30 and 200 Gy). At 150 Gy, the number of adults that developed from irradiated eggs, larvae and puparia was lower than in the untreated control. Fecundity and egg hatchability decreased depending on the doses applied. Reciprocal crosses between irradiated and unirradiated flies demonstrated that males were more radiotolerant than females. Adult longevity was not affected in all stages. The levels of DNA damage in L. trifolii adults were evaluated using the alkaline comet assay. Our results indicate that electron beam irradiation increased levels of DNA damage in a dose-dependent manner. Moreover, low doses of electron beam irradiation led to the rapid appearance of p53 protein within 6 h; however, it decreased after exposure to high doses (150 Gy and 200 Gy). These results suggest that electron beam irradiation induced not only abnormal development and reproduction but also p53 stability caused by DNA damage in L. trifolii. We conclude that a minimum dose of 150 Gy should be sufficient for female sterilization of L. trifolii. - Highlights: > Electron beam irradiation inhibited normal development of the leaf miner. > Electron beam irradiation inhibited normal reproduction of the leaf miner. > Electron beam irradiation increased levels of DNA damage. > Electron beam irradiation induced p53 stability.

  2. Linking Active Serpentinization with Volatiles and Life: Constraints from IODP Expedition 357 (Atlantis Massif, MAR 30°N) (United States)

    Fruh-Green, G. L.; Rouméjon, S.; Lilley, M. D.; Orcutt, B.


    The Atlantis Massif (MAR, 30°N) is one of the best-studied oceanic core complexes, and recently the target of IODP Expedition 357 (late 2015). This expedition successfully used two seabed rock drills to core 17 shallow holes at 9 sites to study serpentinization processes and microbial activity in the shallow subsurface of highly altered ultramafic and mafic rocks that have been uplifted to the seafloor along a major detachment fault zone. An in situ sensor and water sampling system mounted on the drills recorded real-time variations in dissolved methane, oxygen, pH, oxidation reduction potential, temperature and conductivity during drilling and sampled bottom water after drilling, providing evidence for active serpentinization at all sites. The cores have highly heterogeneous rock types, bulk rock chemistry, and alteration that reflect multiple phases of magmatism and fluid-rock interaction. Recovered ultramafic rocks are dominated by harzburgite with intervals of dunite and minor pyroxenite veins; gabbroic rocks occur as melt impregnations and veins. Dolerite dikes and basaltic rocks represent the latest magmatic activity. The ultramafic rocks show a high degree of serpentinization, with a metasomatic talc-amphibole-chlorite overprint and local rodingitization. Serpentinization textures vary between sites and holes, but are characterized by lizardite mesh textures after olivine, recrystallization textures into chrysotile-polygonal serpentine or antigorite, and veins. Monitoring of borehole fluids during drilling recorded numerous excursions in methane, temperature and redox potential that often correlated with each other. The fact that the excursions occurred both while drilling as well as when no coring operations were taking place implies that horizons of hydrogen- and methane-rich fluids must exist in the basement rocks, and that volatiles are continuously being expelled during active serpentinization at Atlantis Massif.

  3. Chromite and other mineral deposits in serpentine rocks of the Piedmont Upland, Maryland, Pennsylvania, and Delaware (United States)

    Pearre, Nancy C.; Heyl, Allen V.


    The Piedmont Upland in Maryland, Pennsylvania, and Delaware is about 160 miles long and at the most 50 miles wide. Rocks that underlie the province are the Baltimore gneiss of Precambrian age and quartzite, gneiss, schist, marble, phyllite, and greenstone, which make up the Glenarm series of early Paleozoic (?) age. These are intruded by granitic, gabbroic, and ultramaflc igneous rocks. Most of the ultramaflc rocks, originally peridotite, pyroxenite, and dunite, have been partly or completely altered to serpentine and talc; they are all designated by the general term serpentine. The bodies of serpentine are commonly elongate and conformable with the enclosing rocks. Many have been extensively quarried for building, decorative, and crushed stone. In addition, chromite, titaniferous magnetite, rutile, talc and soapstone, amphibole asbestos, magnesite, sodium- rich feldspar (commercially known as soda spar), and corundum have been mined or prospected for in the serpentine. Both high-grade massive chromite and lower grade disseminated chromite occur in very irregular and unpredictable form in the serpentine, and placer deposits of chromite are in and near streams that drain areas underlain by serpentine. A group of unusual minerals, among them kammererite, are typical associates of high-grade massive chromite but are rare in lower grade deposits. Chromite was first discovered in the United States at Bare Hills, Md., around 1810. Between 1820 and 1850, additional deposits were discovered and mined in Maryland and Pennsylvania, including the largest deposit of massive chromite ever found in the United States the Wood deposit, in the State Line district. A second period of extensive chromite mining came during the late 1860's and early 1870's. Production figures are incomplete and conflicting. Estimates from the available data indicate that the aggregate production from 27 of 40 known mines before 1900 totaled between 250,000 and 280,000 tons of lode-chromite ore

  4. A novel sandwich differential capacitive accelerometer with symmetrical double-sided serpentine beam-mass structure (United States)

    Xiao, D. B.; Li, Q. S.; Hou, Z. Q.; Wang, X. H.; Chen, Z. H.; Xia, D. W.; Wu, X. Z.


    This paper presents a novel differential capacitive silicon micro-accelerometer with symmetrical double-sided serpentine beam-mass sensing structure and glass-silicon-glass sandwich structure. The symmetrical double-sided serpentine beam-mass sensing structure is fabricated with a novel pre-buried mask fabrication technology, which is convenient for manufacturing multi-layer sensors. The glass-silicon-glass sandwich structure is realized by a double anodic bonding process. To solve the problem of the difficulty of leading out signals from the top and bottom layer simultaneously in the sandwich sensors, a silicon pillar structure is designed that is inherently simple and low-cost. The prototype is fabricated and tested. It has low noise performance (the peak to peak value is 40 μg) and μg-level Allan deviation of bias (2.2 μg in 1 h), experimentally demonstrating the effectiveness of the design and the novel fabrication technology.

  5. Mineral textures in Serpentine-hosted Alkaline Springs from the Oman ophiolite (United States)

    Giampouras, Manolis; Garcia-Ruiz, Juan Manuel; Bach, Wolfgang; Garrido, Carlos J.; Los, Karin; Fussmann, Dario; Monien, Monien


    Meteoric water infiltration in ultramafic rocks leads to serpentinization and the formation of subaerial, low temperature, hydrothermal alkaline springs. Here, we present a detailed investigation of the mineral precipitation mechanisms and textural features of mineral precipitates, along as the geochemical and hydrological characterization, of two alkaline spring systems in the Semail ophiolite (Nasif and Khafifah sites, Wadi Tayin massif). The main aim of the study is to provide new insights into mineral and textural variations in active, on-land, alkaline vents of the Oman ophiolite. Discharge of circulating fluids forms small-scale, localized hydrological catchments consisting in unevenly interconnected ponds. Three different types of waters can be distinguished within the pond systems: i) Mg-type; alkaline (7.9 11.6), Ca-OH-rich waters; and iii) Mix-type waters arising from the mixing of Mg-type and Ca-type waters (9.6 1.2). Detailed investigation of individual spring sites allowed the determination of geochemical and hydrological factors controlling the phases and textures of mineralogical assemblages in active, serpentinization-related, alkaline environments. Funding: We acknowledge funding from the People programme (Marie Curie Actions - ITN) of the European Union FP7 under REA Grant Agreement n˚ 608001.

  6. Metal toxicity and biodiversity in serpentine soils: application of bioassay tests and microarthropod index. (United States)

    Visioli, Giovanna; Menta, Cristina; Gardi, Ciro; Conti, Federica Delia


    Eco-toxicological or bioassay tests have been intensively discussed as tools for the evaluation of soil quality. Tests using soil organisms, including microarthropods and plants, allow direct estimates to be made of important soil characteristics and functions. In this study we compared the results obtained by two in vitro standard bioassays following ISO or OECD guidelines: (i) the short term-chronic phytotoxicity germination and root elongation test using three different plant species Cucumis sativus L. (Cucurbitaceae), Lepidium sativum L. (Brassicaceae), and Medicago sativa L. (Fabaceae) and (ii) the inhibition of reproduction of Folsomia candida (Collembola) by soil pollutants to investigate the toxicity of a serpentine soil present in the Italian Apennines, rich in heavy metals such as Ni, Cr, and Co. In addition, microarthropod communities were characterised to evaluate the effects of metal contents on the soil fauna in natural conditions. Abundances, Acari/Collembola ratio, biodiversity indices and the QBS-ar index were calculated. Our results demonstrate that the two in vitro tests distinguish differences correlated with metal and organic matter contents in four sub-sites within the serpentinite. Soil fauna characterisation, not previously performed on serpentine soils, revealed differences in the most vulnerable and adapted groups of microarthropods to soil among the four sub-sites: the microarthropod community was found to be rich in term of biodiversity in the sub-site characterised by a lower metal content and a higher organic matter content and vegetation. Copyright © 2012 Elsevier Ltd. All rights reserved.

  7. Evolution of fracture permeability of ultramafic rocks undergoing serpentinization at hydrothermal conditions: An experimental study (United States)

    Farough, Aida; Moore, Diane E.; Lockner, David A.; Lowell, R. P.


    We performed flow-through laboratory experiments on five cylindrically cored samples of ultramafic rocks, in which we generated a well-mated through-going tensile fracture, to investigate evolution of fracture permeability during serpentinization. The samples were tested in a triaxial loading machine at a confining pressure of 50 MPa, pore pressure of 20 MPa, and temperature of 260°C, simulating a depth of 2 km under hydrostatic conditions. A pore pressure difference of up to 2 MPa was imposed across the ends of the sample. Fracture permeability decreased by 1–2 orders of magnitude during the 200–330 h experiments. Electron microprobe and SEM data indicated the formation of needle-shaped crystals of serpentine composition along the walls of the fracture, and chemical analyses of sampled pore fluids were consistent with dissolution of ferro-magnesian minerals. By comparing the difference between fracture permeability and matrix permeability measured on intact samples of the same rock types, we concluded that the contribution of the low matrix permeability to flow is negligible and essentially all of the flow is focused in the tensile fracture. The experimental results suggest that the fracture network in long-lived hydrothermal circulation systems can be sealed rapidly as a result of mineral precipitation, and generation of new permeability resulting from a combination of tectonic and crystallization-induced stresses is required to maintain fluid circulation.

  8. Efficacy of woody biomass and biochar for alleviating heavy metal bioavailability in serpentine soil. (United States)

    Bandara, Tharanga; Herath, Indika; Kumarathilaka, Prasanna; Hseu, Zeng-Yei; Ok, Yong Sik; Vithanage, Meththika


    Crops grown in metal-rich serpentine soils are vulnerable to phytotoxicity. In this study, Gliricidia sepium (Jacq.) biomass and woody biochar were examined as amendments on heavy metal immobilization in a serpentine soil. Woody biochar was produced by slow pyrolysis of Gliricidia sepium (Jacq.) biomass at 300 and 500 °C. A pot experiment was conducted for 6 weeks with tomato (Lycopersicon esculentum L.) at biochar application rates of 0, 22, 55 and 110 t ha(-1). The CaCl2 and sequential extractions were adopted to assess metal bioavailability and fractionation. Six weeks after germination, plants cultivated on the control could not survive, while all the plants were grown normally on the soils amended with biochars. The most effective treatment for metal immobilization was BC500-110 as indicated by the immobilization efficiencies for Ni, Mn and Cr that were 68, 92 and 42 %, respectively, compared to the control. Biochar produced at 500 °C and at high application rates immobilized heavy metals significantly. Improvements in plant growth in biochar-amended soil were related to decreasing in metal toxicity as a consequence of metal immobilization through strong sorption due to high surface area and functional groups.

  9. Fast flux test facility hazards assessment

    Energy Technology Data Exchange (ETDEWEB)

    Sutton, L.N.


    This document establishes the technical basis in support of Emergency Planning Activities for the Fast Flux Test Facility on the Hanford Site. The document represents an acceptable interpretation of the implementing guidance document for DOE Order 5500.3A. Through this document, the technical basis for the development of facility specific Emergency Action Levels and the Emergency Planning Zone is demonstrated.

  10. Role of serpentinization in the thermal and connected mineral evolution of planetesimals - evaluating possible consequences for exoplanetary systems (United States)

    Góbi, Sándor; Kereszturi, Ákos


    This work gives an overview on the general consequences of serpentinization occurring in the planetesimals of any planetary system. These processes were studied by numerical simulations and the model used - based on earlier works - was developed by implementing the effect of interfacial water. As liquid water is fundamentally required for serpentinization, previous simulations considered only such cases when the initial temperature inside the planetesimal was above the melting point of ice thus neglecting the effect of microscopic water layer completely. However, our results show that it must be taken into account and since it facilitates the reaction to occur at temperatures even as low as 200 K - at which bulk liquid water is completely absent - it substantially broadens the initiation of this alteration regarding the range of possible objects. Investigating the effect of changing the initial parameters helps examine the serpentinization in more general terms. Consequently, the findings described here are ubiquitous and can be applied to any exoplanetary system, even if the initial conditions differ considerably from those that were characteristic to our early Solar system. As a first step towards the generalization of such heating processes, we evaluate the role of composition, starting temperature, porosity and planetesimal size on this heating effect. Besides heat generated by decay of radioactive nuclei, serpentinization should be considered as a 'universal process' in the thermal evolution of planetesimals, and variations of parameters considered in this model might provide an insight into differences between objects in various protoplanetary discs.

  11. Identifying and Quantifying Carbonate and Serpentine Textures and Abundances at Multiple Scales with VSWIR Imaging Spectroscopy, Samail Ophiolite, Oman (United States)

    Leask, E.; Ehlmann, B. L.


    Visible-shortwave infrared (VSWIR) imaging reflectance spectroscopy is a technique that can be used to identify minerals, quantify abundances, and assess textural relationships at many scales, from microscopic(10m/pixel). Here, we assess microscopic-, outcrop-, and airborne-scale data of rocks from serpentine-hosted carbonate springs and veins within the Samail Ophiolite (Oman), a system of interest to terrestrial geologists and an analog for early Martian environments. Multi-scale VSWIR imaging spectroscopy enables study of the fracturing and mineralization processes of serpentinization at multiple spatial scales from sub-mm to meters, as it can be used to identify minerals (even if partially altered), trace veins and quantify their approximate volume, and directly compare active serpentine springs sites to their inactive equivalents. It also allows non-destructive estimation of carbonation. We tested the efficacy of microimaging spectroscopy to evaluate serpentinization textures while simultaneously quantifying abundances of different minerals, comparing values from linear spectral unmixing to traditional techniques (quantitative XRD, EDS/SEM). We find abundances derived typically agree to within 10%. At the microscopic scale, VSWIR imaging spectroscopy identifies spatially coherent rare phases missed by XRD as well as XRD `amorphous' component (partially serpentinized clasts) and can quickly differentiate between carbonates and different phyllosilicate minerals (e.g., serpentine vs. chlorite) through subtle wavelength shifts. While outcrop and landscape-scale data are noisier (and lack key wavelength regions around 1.4 and 1.9 μm due to atmospheric absorptions), for standoff distances 3-15 m it is possible to identify different types/generations of veining and track the specific wavelength of major absorptions as well as their depth/shape as a proxy for crystal size. Network scales of veining and fracturing are quantified and sites of biological activity in

  12. B-type olivine fabric induced by low temperature dissolution creep during serpentinization and deformation in mantle wedge (United States)

    Liu, Wenlong; Zhang, Junfeng; Barou, Fabrice


    The B-type olivine fabric (i.e., the [010] axes subnormal to foliation and the [001] axes subparallel to the lineation) has been regarded as an important olivine fabric for interpreting global trench-parallel S-wave polarization in fore-arc regions. However, strong serpentinization and cold temperature environment in the mantle wedge should inhibit development of the B-type olivine fabric that requires high temperature to activate solid-state plastic deformation. Here we report fabrics of olivine and antigorite generated at low temperatures (300-370 °C) during serpentinization in a fossil mantle wedge of the Val Malenco area, Central Alps. Olivine in the serpentine matrix develops a pronounced B-type fabric, while antigorite in the same matrix displays a strong crystallographic preferred orientation (CPO) with the (001) planes and the [010] axes subparallel to foliation and lineation, respectively. The following evidence leads to the conclusion that the B-type olivine fabric results from dissolution creep assisted by grain boundary sliding (GBS) and grain rotation, rather than solid-state plastic deformation: (1) serpentinization took place at low temperatures and a fluid-enriched environment, ideal for dissolution-precipitation creep; (2) the voids and zigzag boundaries along the interface between antigorite and olivine suggest a fluid dissolution reaction; (3) the primary coarse olivine develops a nearly random fabric, indicating the B-type fabrics in the fine-grained olivine may not be inherited fabrics. These results document for the first time the B-type olivine CPO formed by dissolution creep at low temperatures during serpentinization and provide a mechanism to reconcile petrofabric observations with geophysical observations of trench parallel fast S-wave seismic anisotropy in fore-arc mantle wedge regions.

  13. Serpentinization of abyssal peridotites from the MARK area, Mid-Atlantic Ridge: Sulfur geochemistry and reaction modeling (United States)

    Alt, J.C.; Shanks, Wayne C.


    The opaque mineralogy and the contents and isotope compositions of sulfur in serpentinized peridotites from the MARK (Mid-Atlantic Ridge, Kane Fracture Zone) area were examined to understand the conditions of serpentinization and evaluate this process as a sink for seawater sulfur. The serpentinites contain a sulfur-rich secondary mineral assemblage and have high sulfur contents (up to 1 wt.%) and elevated ??34Ssulfide (3.7 to 12.7???). Geochemical reaction modeling indicates that seawater-peridotite interaction at 300 to 400??C alone cannot account for both the high sulfur contents and high ??34Ssulfide. These require a multistage reaction with leaching of sulfide from subjacent gabbro during higher temperature (???400??C) reactions with seawater and subsequent deposition of sulfide during serpentinization of peridotite at ???300??C. Serpentinization produces highly reducing conditions and significant amounts of H2 and results in the partial reduction of seawater carbonate to methane. The latter is documented by formation of carbonate veins enriched in 13C (up to 4.5???) at temperatures above 250??C. Although different processes produce variable sulfur isotope effects in other oceanic serpentinites, sulfur is consistently added to abyssal peridotites during serpentinization. Data for serpentinites drilled and dredged from oceanic crust and from ophiolites indicate that oceanic peridotites are a sink for up to 0.4 to 6.0 ?? 1012 g seawater S yr-1. This is comparable to sulfur exchange that occurs in hydrothermal systems in mafic oceanic crust at midocean ridges and on ridge flanks and amounts to 2 to 30% of the riverine sulfate source and sedimentary sulfide sink in the oceans. The high concentrations and modified isotope compositions of sulfur in serpentinites could be important for mantle metasomatism during subduction of crust generated at slow spreading rates. ?? 2003 Elsevier Science Ltd.

  14. Generation of droplets to serpentine threads on a rotating compact-disk platform (United States)

    Kar, Shantimoy; Joshi, Sumit; Chaudhary, Kaustav; Maiti, Tapas Kumar; Chakraborty, Suman


    We generate stable monodisperse droplets of nano-liter volumes and long serpentine liquid threads in a single, simple "Y"-shaped microchannel mounted on a rotationally actuated lab-on-a-compact-disk platform. Exploitation of Coriolis force offers versatile modus operandi of the present setup, without involving any design complications. Based on the fundamental understanding and subsequent analysis, we present scaling theories consistent with the experimental observations. We also outline specific applications of this technique, in the biological as well as in the physical domain, including digital polymerase chain reaction (PCR), controlled release of medical components, digital counting of colony forming units, hydrogel engineering, optical sensors and scaffolds for living tissues, to name a few.

  15. Integrated axial and tangential serpentine cooling circuit in a turbine airfoil (United States)

    Lee, Ching-Pang; Jiang, Nan; Marra, John J; Rudolph, Ronald J; Dalton, John P


    A continuous serpentine cooling circuit forming a progression of radial passages (44, 45, 46, 47A, 48A) between pressure and suction side walls (52, 54) in a MID region of a turbine airfoil (24). The circuit progresses first axially, then tangentially, ending in a last radial passage (48A) adjacent to the suction side (54) and not adjacent to the pressure side (52). The passages of the axial progression (44, 45, 46) may be adjacent to both the pressure and suction side walls of the airfoil. The next to last radial passage (47A) may be adjacent to the pressure side wall and not adjacent to the suction side wall. The last two radial passages (47A, 48A) may be longer along the pressure and suction side walls respectively than they are in a width direction, providing increased direct cooling surface area on the interiors of these hot walls.

  16. [Participation of nitrifying bacteria in the disintegration of serpentinous ultrabasic rock]. (United States)

    Lebedeva, E V; Lialikova, N N; Bugel'skiĭ, Iu Iu


    Nitrifying bacteria were found to be widely distributed among the products of the weathering crust of ultrabasite rocks. Nitrosospira briensis and Nitrobacter winogradskyi involved in the first and second phases of nitrification, respectively, were detected and isolated as pure cultures. In experiments conducted with a pure culture of Nitrosospira briensis, a correlation was established between degradation of serpentinite by this culture and an increase in the content of nitrites in the growth medium. The presence of nitrogen compounds in the deposits, as well as wide distribution of nitrifying bacteria, suggests that this bacterial group along with other, in particular, heterotrophic microorganisms participates in weathering of serpentinized ultrabasite rocks, leaching of elements, and formation of the weathering crust.

  17. Performance of Polycrystalline Photovoltaic and Thermal Collector (PVT on Serpentine-Parallel Absorbers Design

    Directory of Open Access Journals (Sweden)

    Mustofa Mustofa


    Full Text Available This paper presents the performance of an unglazed polycrystalline photovoltaic-thermal PVT on 0.045 kg/s mass flow rate. PVT combine photovoltaic modules and solar thermal collectors, forming a single device that receive solar radiation and produces heat and electricity simultaneously. The collector figures out serpentine-parallel tubes that can prolong fluid heat conductivity from morning till afternoon. During testing, cell PV, inlet and outlet fluid temperaturs were recorded by thermocouple digital LM35 Arduino Mega 2560. Panel voltage and electric current were also noted in which they were connected to computer and presented each second data recorded. But, in this performance only shows in the certain significant time data. This because the electric current was only noted by multimeter device not the digital one. Based on these testing data, average cell efficieny was about 19%, while thermal efficiency of above 50% and correspondeng cell efficiency of 11%, respectively

  18. Performance of Polycrystalline Photovoltaic and Thermal Collector (PVT on Serpentine-Parallel Absor

    Directory of Open Access Journals (Sweden)



    Full Text Available This paper presents the performance of an unglazed polycrystalline photovoltaic-thermal PVT on 0.045 kg/s mass flow rate. PVT combine photovoltaic modules and solar thermal collectors, forming a single device that receive solar radiation and produces heat and electricity simultaneously. The collector figures out serpentine-parallel tubes that can prolong fluid heat conductivity from morning till afternoon. During testing, cell PV, inlet and outlet fluid temperatures were recorded by thermocouple digital LM35 Arduino Mega 2560. Panel voltage and electric current were also noted in which they were connected to computer and presented each second data recorded. But, in this performance only shows in the certain significant time data. This because the electric current was only noted by multimeter device not the digital one. Based on these testing data, average cell efficiency was about 19%, while thermal efficiency of above 50% and correspondent cell efficiency of 11%, respectively.

  19. Channel geometric scales effect on performance and optimization for serpentine proton exchange membrane fuel cell (PEMFC) (United States)

    Youcef, Kerkoub; Ahmed, Benzaoui; Ziari, Yasmina; Fadila, Haddad


    A three dimensional computational fluid dynamics model is proposed in this paper to investigate the effect of flow field design and dimensions of bipolar plates on performance of serpentine proton exchange membrane fuel cell (PEMFC). A complete fuel cell of 25 cm2 with 25 channels have been used. The aim of the work is to investigate the effect of flow channels and ribs scales on overall performance of PEM fuel cell. Therefore, geometric aspect ratio parameter defined as (width of flow channel/width of rib) is used. Influences of the ribs and openings current collector scales have been studied and analyzed in order to find the optimum ratio between them to enhance the production of courant density of PEM fuel cell. Six kind of serpentine designs have been used in this paper included different aspect ratio varying from 0.25 to 2.33 while the active surface area and number of channels are keeping constant. Aspect ratio 0.25 corresponding of (0.4 mm channel width/ 1.6mm ribs width), and Aspect ratio2.33 corresponding of (0.6 mm channel width/ 1.4mm ribs width. The results show that the best flow field designs (giving the maximum density of current) are which there dimensions of channels width is minimal and ribs width is maximal (Γ≈0.25). Also decreasing width of channels enhance the pressure drop inside the PEM fuel cell, this causes an increase of gazes velocity and enhance convection process, therefore more power generation.

  20. The Potential Role of Formate for Synthesis and Life in Serpentinization Systems (United States)

    Lang, S. Q.; Frueh-Green, G. L.; Bernasconi, S. M.; Brazelton, W. J.; McGonigle, J. M.


    The high hydrogen concentrations produced during water-rock serpentinization reactions provide abundant thermodynamic energy that can drive the synthesis of organic compounds both biotically and abiotically. We investigated the synthesis of abiotic carbon and the metabolic pathways of the microbial inhabitants of the high energy but low diversity serpentinite-hosted Lost City Hydrothermal Field. High concentrations of the organic acid formate can be attributed to two sources. In some locations formate lacks detectable 14C, demonstrating it was formed abiotically from mantle-derived CO2. In other locations there is an additional modern contribution to the formate pool, potentially indicating active cycling with modern seawater dissolved inorganic carbon by microorganisms. The presence of this carbon source is likely critical for the survival of the subsurface microbial communities that inhabit alkaline serpentinization environments, where inorganic carbon is severely limited. Archaeal lipids produced by the Lost City Methanosarcinales (LCMS) also largely lack 14C, requiring their carbon source to be similarly 14C-free. Metagenomic evidence suggests that the LCMS could use formate for methanogenesis and, altogether, the data suggests that these organisms cannot rely on inorganic carbon as their carbon source and substrate for methanogenesis. Considering the lack of dissolved inorganic carbon in this system, the ability to utilize formate may have been a key evolutionary adaptation for survival in serpentinite-hosted environments. In the Lost City system, the LCMS apparently rely upon an abiotically produced organic carbon source, which may enable the Lost City microbial ecosystem to survive in the absence of photosynthesis or its byproducts.

  1. Mapping the Environmental Boundaries for Methanogenesis in Serpentinizing Systems using a Cell-scale Numerical Model (United States)

    Alperin, M. J.; Hoehler, T. M.; McCollom, T.


    Serpentinizing systems occur where liquid water reacts with ultramafic minerals. The reaction releases heat and produces an alkaline fluid that is rich in H2. The abundant H2 suggests that the energetics of methane production by CO2 reduction is highly favorable (ΔG ~ -102 kJ/mol CH4 for [H2] ~ 10-2 M). Given the possibility of subsurface water and ultramafic minerals on Mars, methanogenesis in serpentinizing systems has been considered as a possible model for photosynthesis-independent, extraterrestrial life. However, the high pH (9 - 11) and possibly elevated temperature have a negative impact on the overall cellular energy balance by increasing the cell's maintenance energy and reducing the concentration of CO2 substrate. We developed a reaction-transport model on the scale of a methanogen cell to investigate how the overall bioenergetics of methane production is influenced by the interplay between pH, temperature, and H2 and CO2 concentration. The model differentiates the cell into three basic structural units (cell wall, cell membrane with gated ion channels, and cytoplasm) and employs both thermodynamic and kinetic controls to estimate an upper-limit energy yield as a function of environmental conditions. The model provides a map of the range of environmental extremes for which the energy balance for microbial methane production is positive. The model also provides a tool for exploring the energetics of different metabolic strategies that methanogens could use to cope with stresses associated with life in an alkaline, low-CO2 environment.

  2. Exploration of the Most Alkaline Extreme in a Deep-Sea Serpentine Seamount, the South Chamorro Seamount as an Interface Between Abiotic and Biotic in this Planet (United States)

    Takai, K.; Miyazaki, J.; Morono, Y.; Inagaki, F.; Kubota, K.; Moyer, C.; Seewald, J.; Wheat, G.


    The most alkaline-extreme environment beneath the Mariana Forearc serpentine seamount was geochemicallly and microbiologicallly explored. The results suggested that the environment was a marginal between abiotic and biotic terrains in this planet.

  3. Critical flux determination by flux-stepping

    DEFF Research Database (Denmark)

    Beier, Søren; Jonsson, Gunnar Eigil


    In membrane filtration related scientific literature, often step-by-step determined critical fluxes are reported. Using a dynamic microfiltration device, it is shown that critical fluxes determined from two different flux-stepping methods are dependent upon operational parameters such as step...... length, step height, and.flux start level. Filtrating 8 kg/m(3) yeast cell suspensions by a vibrating 0.45 x 10(-6) m pore size microfiltration hollow fiber module, critical fluxes from 5.6 x 10(-6) to 1.2 x 10(-5) m/s have been measured using various step lengths from 300 to 1200 seconds. Thus...

  4. Differences in Growth Characteristics and Dynamics of Elements Absorbed in Seedlings of Three Spruce Species Raised on Serpentine Soil in Northern Japan (United States)



    • Background and Aims Serpentine soils are characterized by the presence of heavy metals (Ni and Cr) and excess Mg; these elements often suppress plant growth. Picea glehnii is nevertheless distributed widely on serpentine soils in northern Japan. Growth characteristics were compared among P. glehnii, Picea jezoensis (distributed in the same region) and Picea abies (planted for timber production), and concentrations of elements in various tissues over time and the amount of ectomycorrhizal infection in short roots were evaluated. • Methods Seedlings of three spruce species were planted in two types of experimental plots, comprising serpentine soil and brown forest (non-serpentine) soil, and these seedlings were grown for 3 years. Growth, ectomycorrhizal infection of short roots, and elemental composition of tissues were examined. • Key Results The total dry mass of P. glehnii planted on serpentine soil was almost the same as on brown forest soil, and a large number of needles survived to reach later age classes. By contrast, growth of P. jezoensis and P. abies in serpentine soil was significantly less than in brown forest soil, and needle shedding was accelerated. Moreover, roots of seedlings of P. glehnii on serpentine soil were highly infected with ectomycorrhiza, and the concentration of Ni in needles and roots of P. glehnii was the lowest of the three species. • Conclusions Picea glehnii has a high ability to maintain a low concentration of Ni, and the ectomycorrhizal infection may have the positive effect of excluding Ni. As a result, P. glehnii is more tolerant than the other spruce species to serpentine soil conditions. PMID:15650010

  5. Carbonate control of H2 and CH4 production in serpentinization systems at elevated P-Ts (United States)

    Jones, L. Camille; Rosenbauer, Robert; Goldsmith, Jonas I.; Oze, Christopher


    Serpentinization of forsteritic olivine results in the inorganic synthesis of molecular hydrogen (H2) in ultramafic hydrothermal systems (e.g., mid-ocean ridge and forearc environments). Inorganic carbon in those hydrothermal systems may react with H2 to produce methane (CH4) and other hydrocarbons or react with dissolved metal ions to form carbonate minerals. Here, we report serpentinization experiments at 200°C and 300 bar demonstrating Fe2+ being incorporated into carbonates more rapidly than Fe2+ oxidation (and concomitant H2 formation) leading to diminished yields of H2 and H2-dependent CH4. In addition, carbonate formation is temporally fast in carbonate oversaturated fluids. Our results demonstrate that carbonate chemistry ultimately modulates the abiotic synthesis of both H2 and CH4 in hydrothermal ultramafic systems and that ultramafic systems present great potential for CO2-mineral sequestration.

  6. Secondary metabolites and metal content dynamics in Teucrium montanum L. and Teucrium chamaedrys L. from habitats with serpentine and calcareous substrate. (United States)

    Zlatić, Nenad M; Stanković, Milan S; Simić, Zoran S


    The purpose of this comparative analysis is the determination of the total quantity of metals (Mg, Ca, K, Ni, Fe, Mn, Zn, Cu, Cr and Pb) in soil samples, above ground plant parts and tea made of plants Teucrium montanum and T. chamaedrys from different serpentine and calcareous habitats as well as of the total quantity of phenolic compounds and antioxidant activity. The obtained results showed that the quantities of certain metals (Mg, Fe, Ni and Mn) in the soil from the serpentine habitats were greater in comparison with other metals (Ca, Zn and Pb) which were more frequently found in the soil from the calcareous habitats. The results demonstrated that the analysed plant samples from the serpentine habitats contained higher quantity of Fe, Ni and Cr as opposed to the plant samples from the calcareous habitats which contained greater quantity of Ca and Zn. Although the studied species accumulate analysed metals in different quantities, depending on the substrate type, they are not hyperaccumulators of these metals. The use of these species from serpentine habitats for tea preparation is safe to a great extent, because in spite of the determined metal absorption by plant organs, the tea does not contain dangerous quantity of heavy metals. The results showed greater total quantity of phenolic compounds and the higher level of antioxidant activity in the plant samples from serpentine habitats in comparison with the samples from calcareous habitats, which is an indicator of one of the mechanisms of adaptation to the serpentine habitat conditions.

  7. From transmission error measurement to Pulley-Belt slip determination in serpentine belt drives : influence of tensioner and belt characteristics


    Manin, Lionel; Michon, Guilhem; Rémond, Didier; Dufour, Regis


    Serpentine belt drives are often used in front end accessory drive of automotive engine. The accessories resistant torques are getting higher within new technological innovations as stater-alternator, and belt transmissions are always asked for higher capacity. Two kind of tensioners are used to maintain minimum tension that insure power transmission and minimize slip: dry friction or hydraulic tensioners. An experimental device and a specific transmission error measurement method have been u...

  8. The pretzel sign: angiographic pattern of tortuous intra-aneurysmal blood flow in a giant serpentine aneurysm.

    LENUS (Irish Health Repository)

    Fanning, N F


    Giant serpentine aneurysms (GSAs) form a specific subgroup of giant cerebral aneurysms that have pathognomonic angiographic features. We report the angiographic findings of a GSA demonstrating a striking convoluted dynamic flow pattern, which we have called the \\'pretzel sign\\'. The aneurysm was successfully treated by permanent occlusion of the parent vessel using a detachable balloon. GSAs should be identified prior to treatment in view of their particular management requirements.

  9. Mineralogical and experimental study of serpentine minerals and ultramafic rocks with application to carbon capture and storage by mineralisation


    Lacinska, Alicja M.


    The type of feedstock and host rock utilised in ex situ and in situ Carbon Capture and Storage by Mineralisation (CCSM) is an important aspect of these technologies, and detailed appraisal of candidate mineral/rock performance in the presence of CO2 may greatly improve CCSM efficiency. Here, a detailed mineralogical and geochemical investigation of serpentine minerals and ultramafic rocks under laboratory-controlled experiments simulating ex situ and in situ process conditions is presented. ...

  10. A highly compliant serpentine shaped polyimide interconnect for front-end strain relief in chronic neural implants

    Directory of Open Access Journals (Sweden)

    Viswanath eSankar


    Full Text Available While the signal quality of recording neural electrodes is observed to degrade over time, the degradation mechanisms are complex and less easily observable. Recording microelectrodes failures are attributed to different biological factors such as tissue encapsulation, immune response, and disruption of blood-brain barrier (BBB and non-biological factors such as strain due to micromotion, insulation delamination, corrosion, and surface roughness on the recording site (Polikov et. al., 2005; Prasad et. al., 2011; Streit et. al., 2012; Prasad et. al., 2012. Strain due to brain micromotion is considered to be one of the important abiotic factors contributing to the failure of the neural implants. To reduce the forces exerted by the electrode on the brain, a high compliance 2D serpentine shaped electrode cable was designed, simulated, and measured using polyimide as the substrate material. Serpentine electrode cables were fabricated using MEMS microfabrication techniques, and the prototypes were subjected to load tests to experimentally measure the compliance. The compliance of the serpentine cable was numerically modeled and quantitatively measured to be up to 10 times higher than the compliance of a straight cable of same dimensions and material.

  11. Microbial Substrate Use at Sites of Continental Serpentinization: The Tablelands, NL, CAD and the Cedars, CA, USA (United States)

    Morrill, P. L.; Rietze, A.; Kohl, L.; Miles, S.; Kavanagh, H.; Cox, A.; Brazelton, W. J.; Ishii, S.; Sherwood Lollar, B.; Schrenk, M. O.; Nealson, K. H.; Ziegler, S. E.; Ono, S.; Wang, D. T.; Lang, S. Q.; Cumming, E.


    Ultra-basic reducing springs at continental sites of serpentinization act as portals into the biogeochemistry of a subsurface ultramafic environment rich in hydrogen and methane gases. Field data and results from substrate addition microcosm experiments will be presented from two contrasting continental sites of serpentinization: the Tablelands, NL, CAN and The Cedars, CA, USA both Phanerozoic in age. These continental sites share geochemical characteristics that make these environments challenging for life, such as high pH, low Eh, scarce electron acceptors, and limited dissolved inorganic carbon for autotrophic growth. However, microbiological analyses have demonstrated that life does indeed exist in these environments. While environmental genomic studies indicated the potential metabolic capabilities of microorganisms in the sites, actual microbial metabolic activities in these environments remain unknown. To expand the understanding of biogeochemistry of the sites, we are conducting studies focusing on chemical and isotopic measurements, carbon substrate utilization, energy sources, and metabolic pathways of the microorganisms. Thus far, in situ geochemical data suggests that the methane from the Tablelands is primarily non-microbial, while the methane from The Cedars likely has some microbial contributions. To date, substrate addition microcosm experiments show no microbial production of methane from Tablelands' water and sediments. However, microbial carbon monoxide utilization has been observed in Tableland microcosms, but not in The Cedars microcosms. These results demonstrate how geochemistry and substrate addition experiments can be complementary for the determination of the processes favored at these continental sites of serpentinization.

  12. Albanian violets of the section Melanium, their morphological variability, genetic similarity and their adaptations to serpentine or chalk soils. (United States)

    Słomka, Aneta; Godzik, Barbara; Szarek-Łukaszewska, Grażyna; Shuka, Lulëzim; Hoef-Emden, Kerstin; Bothe, Hermann


    Violets of the section Melanium from Albanian serpentine and chalk soils were examined for their taxonomic affiliations, their ability to accumulate heavy metals and their colonization by arbuscular mycorrhizal fungi (AMF). The sequence analysis of the ITS1-5.8S rDNA-ITS2 region showed that all the sampled six Albanian violets grouped between Viola lutea and Viola arvensis, but not with Viola tricolor. The fine resolution of the ITS sequences was not sufficient for a further delimitation of the Albanian violets within the V. lutea-V. arvensis clade. Therefore, the Albanian violets were classified by a set of morphological characters. Viola albanica, Viola dukadjinica and Viola raunsiensis from serpentine soils as well as Viola aetolica from a chalk meadow were unambiguously identified, whereas the samples of Viola macedonica showed high morphological variability. All the violets, in both roots and shoots contained less than or similar levels of heavy metals as their harboring soils, indicating that they were heavy metal excluders. All the violets were strongly colonized by AMF with the remarkable exception of V. albanica. This violet lived as a scree creeper in shallow serpentine soil where the concentration of heavy metals was high but those of P, K and N were scarce. Copyright © 2014 Elsevier GmbH. All rights reserved.

  13. The Effect of Inertia on the Flow and Mixing Characteristics of a Chaotic Serpentine Mixer

    Directory of Open Access Journals (Sweden)

    Tae Gon Kang


    Full Text Available As an extension of our previous study, the flow and mixing characteristics of a serpentine mixer in non-creeping flow conditions are investigated numerically. A periodic velocity field is obtained for each spatially periodic channel with the Reynolds number (Re ranging from 0.1 to 70 and the channel aspect ratio from 0.25 to one. The flow kinematics is visualized by plotting the manifold of the deforming interface between two fluids. The progress of mixing affected by the Reynolds number and the channel geometry is characterized by a measure of mixing, the intensity of segregation, calculated using the concentration distribution. A mixer with a lower aspect ratio, which is a poor mixer in the creeping flow regime, turns out to be an efficient one above a threshold value of the Reynolds number, Re = 50. This is due to the combined effect of the enhanced rotational motion of fluid particles and back flows near the bends of the channel driven by inertia. As for a mixer with a higher aspect ratio, the intensity of segregation has its maximum around Re = 30, implying that inertia does not always have a positive influence on mixing in this mixer.

  14. A nonlinear analysis of the terahertz serpentine waveguide traveling-wave amplifier

    Energy Technology Data Exchange (ETDEWEB)

    Li, Ke, E-mail:; Cao, Miaomiao, E-mail: [Key Laboratory of High Power Microwave Sources and Technologies, Institute of Electronics, Chinese Academy of Sciences, Beijing 100190 (China); Institute of Electronics, University of Chinese Academy of Sciences, Beijing 100190 (China); Liu, Wenxin, E-mail:; Wang, Yong, E-mail: [Key Laboratory of High Power Microwave Sources and Technologies, Institute of Electronics, Chinese Academy of Sciences, Beijing 100190 (China)


    A nonlinear model for the numerical simulation of terahertz serpentine waveguide traveling-wave tube (SW-TWT) is described. In this model, the electromagnetic wave transmission in the SW is represented as an infinite set of space harmonics to interact with an electron beam. Analytical expressions for axial electric fields in axisymmetric interaction gaps of SW-TWTs are derived and compared with the results from CST simulation. The continuous beam is treated as discrete macro-particles with different initial phases. The beam-tunnel field equations, space-charge field equations, and motion equations are combined to solve the beam-wave interaction. The influence of backward wave and relativistic effect is also considered in the series of equations. The nonlinear model is used to design a 340 GHz SW-TWT. Several favorable comparisons of model predictions with results from a 3-D Particle-in-cell simulation code CHIPIC are presented, in which the output power versus beam voltage and interaction periods are illustrated. The relative error of the predicted output power is less than 15% in the 3 dB bandwidth and the relative error of the saturated length is less than 8%.The results show that the 1-D nonlinear analysis model is appropriate to solve the terahertz SW-TWT operation characteristics.

  15. Temperature distribution on the MEA surface of a PEMFC with serpentine channel flow bed (United States)

    Wang, Maohai; Guo, Hang; Ma, Chongfang

    Knowledge of the temperature distribution on the membrane electrode assembly (MEA) surface and heat transfer processes inside a proton exchange membrane fuel cell (PEMFC) is helpful to improvement of cell reliability, durability and performance. The temperature fields on the surface of MEA fixed inside a proton exchange membrane fuel cell with a serpentine channel flow bed were measured by infrared imaging technology under non-humidification conditions. The temperature distributions over the MEA surface under whole channel region were achieved. The experimental results show that the downstream temperatures are higher than the upstream. The hot region on the MEA surface is easy to locate from the infrared temperature image. The mean temperature on the MEA surface and the cell temperature both increase with the current density. Higher current density makes the non-uniformity of temperature distribution on the MEA surface worse. The loading time significantly affects the temperature distribution. Compared with the electrical performance of the cell, the MEA's temperatures need much more time to reach stable. The results indicate that isothermal assumption is not appropriate for a modeling of PEMFCs, and monitoring the temperature of external surface of the flow field plate or end plate cannot supply accurate reference to control the temperatures on MEA surface.

  16. One-carbon (bio ?) Geochemistry in Subsurface Waters of the Serpentinizing Coast Range Ophiolite (United States)

    Hoehler, Tori M.; Mccollom, Tom; Schrenk, Matt; Cardace, Dawn


    Serpentinization - the aqueous alteration of ultramafic rocks - typically imparts a highly reducing and alkaline character to the reacting fluids. In turn, these can influence the speciation and potential for metabolism of one-carbon compounds in the system. We examined the aqueous geochemistry and assessed the biological potential of one-carbon compounds in the subsurface of the McLaughlin Natural Reserve (Coast Range Ophiolite, California, USA). Fluids from wells sunk at depths of 25-90 meters have pH values ranging from 9.7 to 11.5 and dissolved inorganic carbon (DIC concentrations) generally below 60 micromolar. Methane is present at concentrations up to 1.3 millimolar (approximately one-atmosphere saturation), and hydrogen concentrations are below 15 nanomolar, suggesting active consumption of H2 and production of CH4. However, methane production from CO2 is thermodynamically unfavorable under these conditions. Additionally, the speciation of DIC predominantly into carbonate at these high pH values creates a problem of carbon availability for any organisms that require CO2 (or bicarbonate) for catabolism or anabolism. A potential alternative is carbon monoxide, which is present in these waters at concentrations 2000-fold higher than equilibrium with atmospheric CO. CO is utilized in a variety of metabolisms, including methanogenesis, and bioavailability is not adversely affected by pH-dependent speciation (as for DIC). Methanogenesis from CO under in situ conditions is thermodynamically favorable and would satisfy biological energy requirements with respect to both Gibbs Energy yield and power.

  17. One-carbon (bio?)geochemistry in subsurface waters of the serpentinizing Coast Range Ophiolite (United States)

    Hoehler, T. M.; McCollom, T.; Schrenk, M. O.; Kubo, M.; Cardace, D.


    Serpentinization - the aqueous alteration of ultramafic rocks - typically imparts a highly reducing and alkaline character to the reacting fluids. In turn, these can influence the speciation and potential for metabolism of one-carbon compounds in the system. We examined the aqueous geochemistry and assessed the biological potential of one-carbon compounds in the subsurface of the McLaughlin Natural Reserve (Coast Range Ophiolite, California, USA). Fluids from wells sunk at depths of 25-90 meters have pH values ranging from 9.7 to 11.5 and dissolved inorganic carbon (DIC concentrations) generally below 60 micromolar. Methane is present at concentrations up to 1.3 millimolar (approximately one-atmosphere saturation), and hydrogen concentrations are below 15 nanomolar, suggesting active consumption of H2 and production of CH4. However, methane production from CO2 is thermodynamically unfavorable under these conditions. Additionally, the speciation of DIC predominantly into carbonate at these high pH values creates a problem of carbon availability for any organisms that require CO2 (or bicarbonate) for catabolism or anabolism. A potential alternative is carbon monoxide, which is present in these waters at concentrations 2000-fold higher than equilibrium with atmospheric CO. CO is utilized in a variety of metabolisms, including methanogenesis, and bioavailability is not adversely affected by pH-dependent speciation (as for DIC). Methanogenesis from CO under in situ conditions is thermodynamically favorable and would satisfy biological energy requirements with respect to both Gibbs Energy yield and power.

  18. A hydrological and geochemical analysis of chromium mobilization from serpentinized ultramafic rocks and serpentine soils at the McLaughlin Natural Reserve, Lake County, California (United States)

    McClain, C.; Maher, K.; Fendorf, S.


    California recently adopted the nation's first Public Health Goal (PHG) for hexavalent chromium (Cr(VI)) in drinking water (0.02 μg/L) because recent studies show that Cr(VI) may be carcinogenic through ingestion. Approximately one third of drinking water sources in California tested for Cr(VI) have levels above 1 μg/L and thus may pose a risk to human health. Cr(VI) can enter drinking water directly from anthropogenic sources or from the release of Cr(III) in natural geogenic sources such as rocks, sediments and soils, and subsequent oxidation to Cr(VI) by manganese oxides. Ultramafic rocks and related soils and sediments have elevated Cr and Mn concentrations compared to other rock types. To study the release of Cr(VI) to water from geogenic sources we examined the local hydrology, groundwater, surface water, soils and sediment compositions within a serpentinized ultramafic terrain along Hunting Creek, a tributary to Putah Creek, at the McLaughlin Natural Reserve in the California Coast Ranges. The hydrology of the site is dominated by fracture flow: groundwater wells were screened in fractured serpentinite, and springs emanating from fractured serpentinite bedrock contribute to the baseflow of Hunting Creek. Soil profiles and bedrock were analyzed for major and trace elements by XRF to assess the fate of Cr during weathering and the distribution of manganese oxides. These factors, along with mineral surface areas, microbial activity, water content, and flow dynamics, collectively control the oxidation of Cr(III). The prevalence of Mg-HCO3 waters at this site indicates that waters are primarily interacting with serpentinites. Pyroxenes are slightly to highly undersaturated and amorphous silica is saturated. Smectite clays, chlorite, and hydromagnesite are supersaturated, indicating formation of secondary mineral phases is favorable and could lead to the inclusion of Cr(III). Total Cr concentrations in surface and groundwater vary from 0.1-26 μg/L and Cr

  19. Flux-P: Automating Metabolic Flux Analysis

    Directory of Open Access Journals (Sweden)

    Birgitta E. Ebert


    Full Text Available Quantitative knowledge of intracellular fluxes in metabolic networks is invaluable for inferring metabolic system behavior and the design principles of biological systems. However, intracellular reaction rates can not often be calculated directly but have to be estimated; for instance, via 13C-based metabolic flux analysis, a model-based interpretation of stable carbon isotope patterns in intermediates of metabolism. Existing software such as FiatFlux, OpenFLUX or 13CFLUX supports experts in this complex analysis, but requires several steps that have to be carried out manually, hence restricting the use of this software for data interpretation to a rather small number of experiments. In this paper, we present Flux-P as an approach to automate and standardize 13C-based metabolic flux analysis, using the Bio-jETI workflow framework. Exemplarily based on the FiatFlux software, it demonstrates how services can be created that carry out the different analysis steps autonomously and how these can subsequently be assembled into software workflows that perform automated, high-throughput intracellular flux analysis of high quality and reproducibility. Besides significant acceleration and standardization of the data analysis, the agile workflow-based realization supports flexible changes of the analysis workflows on the user level, making it easy to perform custom analyses.

  20. Transient computation fluid dynamics modeling of a single proton exchange membrane fuel cell with serpentine channel (United States)

    Hu, Guilin; Fan, Jianren

    The proton exchange membrane fuel cell (PEMFC) has become a promising candidate for the power source of electrical vehicles because of its low pollution, low noise and especially fast startup and transient responses at low temperatures. A transient, three-dimensional, non-isothermal and single-phase mathematical model based on computation fluid dynamics has been developed to describe the transient process and the dynamic characteristics of a PEMFC with a serpentine fluid channel. The effects of water phase change and heat transfer, as well as electrochemical kinetics and multicomponent transport on the cell performance are taken into account simultaneously in this comprehensive model. The developed model was employed to simulate a single laboratory-scale PEMFC with an electrode area about 20 cm 2. The dynamic behavior of the characteristic parameters such as reactant concentration, pressure loss, temperature on the membrane surface of cathode side and current density during start-up process were computed and are discussed in detail. Furthermore, transient responses of the fuel cell characteristics during step changes and sinusoidal changes in the stoichiometric flow ratio of the cathode inlet stream, cathode inlet stream humidity and cell voltage are also studied and analyzed and interesting undershoot/overshoot behavior of some variables was found. It was also found that the startup and transient response time of a PEM fuel cell is of the order of a second, which is similar to the simulation results predicted by most models. The result is an important guide for the optimization of PEMFC designs and dynamic operation.

  1. Hibridación de medios en la confluencia de forma, tiempo y espacio: de la Danse Serpentine al Capturing Dance = Hybridization of artistic media on the crossroad of Shape, Time and Space: from Danse Serpentine to Capturing Dance


    Clara Laguillo Abbad


    Los hermanos Lumière registraron la Danse Serpentine de Loïe Fuller en 1896. Mediante el movimiento de sus telas, Fuller investigaba la luz teatral. Y a través del registro y posterior tinte de sus fotogramas, los Lumière inauguraban el lenguaje cinematográfico. Así pues, cabe decir que ya en el siglo XIX, lo performativo y su registro iban de la mano.En mayo de 2011 las artistas pluridisciplinares Merche Blasco, Mimi Yin y Christine Doempke, presentaban en la Tisch School of the Arts de la N...

  2. Detachment Faulting, Serpentinization, Fluids and Life: Preliminary Results of IODP Expedition 357 (Atlantis Massif, MAR 30°N) (United States)

    Fruh-Green, G. L.; Orcutt, B.; Green, S.; Cotterill, C.


    We present an overview of IODP Expedition 357, which successfully used two seabed rock drills to core 17 shallow holes at 9 sites across Atlantis Massif (Mid-Atlantic Ridge 30°N). A major goal of this expedition is to investigate serpentinization processes and microbial activity in the shallow subsurface of highly altered ultramafic and mafic sequences that have been uplifted to the seafloor along a major detachment fault zone. More than 57 m of core were recovered, with borehole penetration ranging from 1.3 to 16.4 meters below seafloor, and core recovery as high as 75% of total penetration. The cores show highly heterogeneous rock type, bulk rock chemistry and alteration that reflect multiple phases of magmatism and fluid-rock interaction within the detachment fault zone. In cores along an E-W transect of the southern wall, recovered mantle peridotites are locally intruded by gabbroic and doleritic dikes and veins. The proportion of mafic rocks are volumetrically less than the amount of mafic rocks recovered previously in the central dome at IODP Site U1309, suggesting a lower degree of melt infiltration into mantle peridotite at the ridge-transform intersection. New technologies were developed and successfully applied for the first time: (1) an in-situ sensor package and water sampling system on each seabed drill measured real-time variations in dissolved methane, oxygen, pH, oxidation reduction potential, temperature, and conductivity during drilling and took water samples after drilling; (2) a borehole plug system to seal the boreholes was successfully deployed at two sites to allow access for future sampling; and (3) delivery of chemical tracers into the drilling fluids for contamination testing. We will provide an overview of the drilling strategy and preliminary results of Expedition 357, and highlight the role of serpentinization in sustaining microbial communities in a region of active serpentinization and low temperature hydrothermal alteration.

  3. Out of the dark: Transitional subsurface-to-surface microbial diversity in a terrestrial serpentinizing seep (Manleluag, Pangasinan, the Philippines

    Directory of Open Access Journals (Sweden)

    Kristin eWoycheese


    Full Text Available In the Zambales ophiolite range terrestrial serpentinizing fluid seeps host diverse microbial assemblages. The fluids fall within the profile of Ca2+-OH--type waters, indicative of active serpentinization, and are low in dissolved inorganic carbon (<0.5 ppm. Influx of atmospheric carbon dioxide affects the solubility of calcium carbonate as distance from the source increases, triggering the formation of meter-scale travertine terraces. Samples were collected at the source and along the outflow channel to determine subsurface microbial community response to surface exposure. DNA was extracted and submitted for high-throughput 16S rRNA gene sequencing on the Illumina MiSeq platform. Taxonomic assignment of the sequence data indicates that 8.1% of the total sequence reads at the source of the seep affiliate with the genus Methanobacterium. Other major classes detected at the source include anaerobic taxa such as Bacteroidetes (40.7% of total sequence reads and Firmicutes (19.1% of total reads. Hydrogenophaga spp. increase in relative abundance as redox potential increases. At the carbonate terrace, 45% of sequence reads affiliate with Meiothermus spp. Taxonomic observations and geochemical data suggest that several putative metabolisms may be favorable, including hydrogen oxidation, H2-associated sulfur cycling, methanogenesis, methanotrophy, nitrogen fixation, ammonia oxidation, denitrification, nitrate respiration, methylotrophy, carbon monoxide respiration, and ferrous iron oxidation, based on capabilities of nearest known neighbors. Scanning electron microscopy and energy dispersive X-ray spectroscopy suggest that microbial activity produces chemical and physical traces in the precipitated carbonates forming downstream of the seep’s source. These data provide context for future serpentinizing seep ecosystem studies, particularly with regards to tropical biomes.

  4. Effect of Louver Angle on Performance of Heat Exchanger With Serpentine Fins and Flat Tubes in Periodic Frosting


    Hrnjak, Predrag S.; Zhang, Ping; Rennels, Chris


    This paper presents the results of an experimental study on the air-side pressure drop and overall heat transfer coefficient characteristics for serpentine-louvered-fin, microchannel heat exchanger in periodic frosting. It focuses on quantification of the effects of louver angle on heat transfer and pressure drop and on defrost and refrost times. Nine heat exchangers differing in louver angle and fin pitch (i.e. louver angle 15º to 39º and fin pitch 15 to 18 fpi) are studied. The face velocit...

  5. Note: Non-destructive measurement of thermal effusivity of a solid and liquid using a freestanding serpentine sensor-based 3ω technique. (United States)

    Qiu, L; Zheng, X H; Zhu, J; Tang, D W


    A non-destructive thermal effusivity characterization method described as a freestanding serpentine sensor-based 3ω technique was reported. This freestanding serpentine sensor was fabricated by the mature flexible printed circuit production technique. Expression for the temperature response of the freestanding serpentine sensor with respect to the thermal effusivity of the test sample was presented. The technique was further verified by measuring four kinds of standard samples at room temperature. Experimental results which well agree with reference values demonstrate the new technique is of great application value to thermal effusivity characterization of solids, liquids, and structures to which the conventional 3ω technique is not applicable, e.g., solids with porous surfaces.

  6. Insights into the fine-grained fraction of serpentine mud from the Southern Chamorro seamount (ODP Leg 195): A combined XRD, RFA and TEM-EDS study (United States)

    Lischka, M.; Meschede, M.; Warr, L. N.


    Serpentine mud volcanoes in the outer forearc of the Izu-Bonin-Mariana subduction system occur in a restricted zone, 50km - 120 km away from the trench axis [Fryer et al., 1985]. The morphotectonic elements of the forearc are dominated by horst and graben structures, caused by extensional movements and normal fault systems related to seamount subduction [Fryer et al., 2000; Stern and Smooth, 1998]. These faults may provide conduits for the diapiric uprising of low density serpentine, extruding at the seafloor in stratovolcanic like structures. Released fluids from the subducted slab at estimated depths of approximately 30km are considered to hydrate the forearc mantle wedge along those fractures [Benton et al., 2001; Mottl et al., 2003; Rübke et al., 2004]. During the formation of the fault gouge, serpentine-bodies entrained xenoliths and xenocrysts from the surrounding rocks and are exhumed towards the surface [Fryer et al., 1990]. In our investigation we focus on the silty to clay-sized particle fraction of the serpentine mud matrix, drilled during ODP Leg 195 at site 1200E. We analysed the bulk mineral composition with X-ray diffraction methods on random powder samples, supplemented by X-ray fluorescence measurements on 25 samples. To obtain more insights into the mineralogy fabric and microstructure of the samples, electron microscopy and electron dispersive spectroscopy were used to determine the crystal-chemistry and alteration textures. Particular emphasis was given on determining serpentine polymorphs and the nature of other phyllosilicates and their geochemical composition and constraints. Geochemical observation of the secondary mineral phases should allow us to reconstruct the processes linked with the migration of fluids and volatile components during subduction related metamorphism affecting the mantle wedge. Based on the new data we characterize the conditions of alteration products within a subduction factory, related to the diapiric deposition of

  7. Large and variable genome size unrelated to serpentine adaptation but supportive of cryptic sexuality in Cenococcum geophilum. (United States)

    Bourne, Elizabeth C; Mina, Diogo; Gonçalves, Susana C; Loureiro, João; Freitas, Helena; Muller, Ludo A H


    Estimations of genome size and its variation can provide valuable information regarding the genetic diversity of organisms and their adaptation potential to heterogeneous environments. We used flow cytometry to characterize the variation in genome size among 40 isolates of Cenococcum geophilum, an ectomycorrhizal fungus with a wide ecological and geographical distribution, obtained from two serpentine and two non-serpentine sites in Portugal. Besides determining the genome size and its intraspecies variation, we wanted to assess whether a relationship exists between genome size and the edaphic background of the C. geophilum isolates. Our results reveal C. geophilum to have one of the largest genome sizes so far measured in the Ascomycota, with a mean haploid genome size estimate of 0.208 pg (203 Mbp). However, no relationship was found between genome size and the edaphic background of the sampled isolates, indicating genetic and demographic processes to be more important for shaping the genome size variation in this species than environmental selection. The detection of variation in ploidy level among our isolates, including a single individual with both presumed haploid and diploid nuclei, provides supportive evidence for a possible cryptic sexual or parasexual cycle in C. geophilum (although other mechanisms may have caused this variation). The existence of such a cycle would have wide significance, explaining the high levels of genetic diversity and likelihood of recombination previously reported in this species, and adds to the increasing number of studies suggesting sexual cycles in previously assumed asexual fungi.

  8. Effects of Straight and Serpentine Flow Field Designs on Temperature Distribution in Proton Exchange Membrane (PEM Fuel Cell

    Directory of Open Access Journals (Sweden)

    Zaman Izzuddin


    Full Text Available Proton exchange membrane fuel cells or sometimes called as polymer electrolyte membrane (PEM fuel cells is a device for energy transformation in a changing process from one form of energy to another form of energy. It became as an alternative especially for future use in stationary and vehicular applications. PEM fuel cells provide high efficiency and power density with null emission, low operating temperature, quickly start and long life. One of the aspects that are crucial in optimizing the PEM fuel cells performance is a flow field geometry. In this paper, a simulation case of PEM fuel cells was simulated to determine effects of a straight and serpentine flow field on temperature distribution in PEM fuel cells. ANSYS Fluent software was used to simulate 3-dimensional models of single PEM fuel cells in order to determine the effects of changes in the geometry flow field on temperature distributions. Results showed that the serpentine flow field design produces a better temperature distribution along the membrane. The simulation result shows a good agreement with the experiment, thus boost a higher confidence in the results to determine the effectiveness of the flow field design in PEM fuel cells.

  9. Experimental investigation of forced convective heat transfer performance in nanofluids of Al2O3/water and CuO/water in a serpentine shaped micro channel heat sink (United States)

    Sivakumar, A.; Alagumurthi, N.; Senthilvelan, T.


    The microchannels are device used to remove high heat fluxes from smaller area. In this experimental research work the heat transfer performance of nanofluids of Al2O3/water and CuO/water were compared. The important character of such fluids is the enhanced thermal conductivity, in comparison with base fluid without considerable alteration in physical and chemical properties. The effect of forced convective heat transfer coefficient was calculated using serpentine shaped microchannel heat exchanger. Furthermore we calculated the forced convective heat transfer coefficient of the nanofluids using theoretical correlations in order to compare the results with the experimental data. The heat transfer coefficient for different particle concentration and temperature were analysed using forced convection heat transfer using nanofluids. The findings indicate considerable enhancement in convective heat transfer coefficient of the nanofluids as compared to the basefluid. The results also shows that CuO/water nanofluid has increased heat transfer coefficient compared with Al2O3/water and base fluids. Moreover the experimental results indicate there is increased forced convective heat transfer coefficient with the increase in nano particle concentration.

  10. Relationships of a growing magnetic flux region to flares

    NARCIS (Netherlands)

    Schadee, A.; Martin, S.F.; Bentley, R.D.; Antalova, A.; Kucera, A.; Dezs, L.; Gesztelyi, L.; Harvey, K.L.; Jones, H.; Livi, S.H.B.; Wang, J.


    Some sites for solar flares are known to develop where new magnetic flux emerges and becomes abutted against opposite polarity pre-existing magnetic flux (review by Galzauskas/1/). We have identified and analyzed the evolution of such flare sites at the boundaries of a major new and growing magnetic

  11. Electron heat flux instability (United States)

    Saeed, Sundas; Sarfraz, M.; Yoon, P. H.; Lazar, M.; Qureshi, M. N. S.


    The heat flux instability is an electromagnetic mode excited by a relative drift between the protons and two-component core-halo electrons. The most prominent application may be in association with the solar wind where drifting electron velocity distributions are observed. The heat flux instability is somewhat analogous to the electrostatic Buneman or ion-acoustic instability driven by the net drift between the protons and bulk electrons, except that the heat flux instability operates in magnetized plasmas and possesses transverse electromagnetic polarization. The heat flux instability is also distinct from the electrostatic counterpart in that it requires two electron species with relative drifts with each other. In the literature, the heat flux instability is often called the 'whistler' heat flux instability, but it is actually polarized in the opposite sense to the whistler wave. This paper elucidates all of these fundamental plasma physical properties associated with the heat flux instability starting from a simple model, and gradually building up more complexity towards a solar wind-like distribution functions. It is found that the essential properties of the instability are already present in the cold counter-streaming electron model, and that the instability is absent if the protons are ignored. These instability characteristics are highly reminiscent of the electron firehose instability driven by excessive parallel temperature anisotropy, propagating in parallel direction with respect to the ambient magnetic field, except that the free energy source for the heat flux instability resides in the effective parallel pressure provided by the counter-streaming electrons.

  12. Modeling low-temperature serpentinization reactions to estimate molecular hydrogen production with implications for potential microbial life on Saturn's moon Enceladus. (United States)

    Zwicker, Jennifer; Smrzka, Daniel; Taubner, Ruth-Sophie; Bach, Wolfgang; Rittmann, Simon; Schleper, Christa; Peckmann, Jörn


    Serpentinization of ultramafic rocks attracts much interest in research on the origin of life on Earth and the search for life on extraterrestrial bodies including icy moons like Enceladus. Serpentinization on Earth occurs in peridotite-hosted systems at slow-spreading mid-ocean ridges, and produces large amounts of molecular hydrogen and methane. These reduced compounds can be utilized by diverse chemosynthetic microbial consortia as a metabolic energy source. Although many hydrothermal vents emit hot and acidic fluids today, it is more likely that life originated in the Archean at sites producing much cooler and more alkaline fluids that allowed for the synthesis and stability of essential organic molecules necessary for life. Therefore, a detailed understanding of water-rock interaction processes during low-temperature serpentinization is of crucial importance in assessing the life-sustaining potential of these environments. In the course of serpentinization, the metasomatic hydration of olivine and pyroxene produces various minerals including serpentine minerals, magnetite, brucite, and carbonates. Hydrogen production only occurs if ferrous iron within iron-bearing minerals is oxidized and incorporated as ferric iron into magnetite. The PHREEQC code was used to model the pH- and temperature-dependent dissolution of olivine and pyroxene to form serpentine, magnetite and hydrogen under pressure and temperature conditions that may exist on Saturn's icy moon Enceladus. Various model setups at 25 and 50°C were run to assess the influence of environmental parameters on hydrogen production. The results reveal that hydrogen production rates depend on the composition of the initial mineral assemblage and temperature. The current assumption is that there is a gaseous phase between Enceladus' ice sheet and subsurface ocean. To test various scenarios, model runs were conducted with and without the presence of a gas phase. The model results show that hydrogen production is

  13. Trace metal contents in wild edible mushrooms growing on serpentine and volcanic soils on the island of Lesvos, Greece. (United States)

    Aloupi, M; Koutrotsios, G; Koulousaris, M; Kalogeropoulos, N


    The objectives of this survey were (1) to assess for the first time the Cd, Cu, Cr, Fe, Mn, Ni, Pb and Zn contents in wild edible mushrooms (Russula delica, Lactarius sanguifluus, Lactarius semisanguifluus, Lactarius deliciosus, Suillus bellinii) from the island of Lesvos, (2) to investigate the metals' variability among the species, as well as in relation to the chemical composition of the underlying soil, comparing mushrooms collected from volcanic and serpentine substrates and (3) to estimate metal intake by the consumption of the mushrooms under consideration. The trace metals in 139 samples were determined by flame or flameless atomic absorption spectroscopy. The median metal concentrations were as follows: Cd: 0.14; Cr: 0.10; Cu: 8.51; Fe: 30.3; Mn: 5.26; Ni: 0.34; Pb: 0.093 and Zn: 64.50, all in mgkg(-1) dry weight. The observed concentrations are among the lowest reported for mushrooms from Europe or Turkey, while Pb and Cd values did not exceed the limits set by the European Union. Significant species- and substrate-related differences in the metal contents were found, but the variability did not follow a uniform pattern for all the metals in all mushroom species. As a general trend, the mushrooms growing in serpentine sites contained higher Cd, Cr and Ni than those from volcanic sites. The calculated bioconcentration factors (BCFs) showed that none of the mushrooms can be regarded as a metal bioaccumulator, although BCF values slightly above unity were found for Zn in the three Lactarius species, and for Cu in R. delica. The studied mushrooms could supply considerable amounts of essential metals such as Zn and Cr. On the other hand, the consumption of R. delica collected from volcanic soils could provide 12% of the Cd daily tolerable intake and as high as 53% when collected from serpentine soils. Nonetheless, our results indicate that the regular consumption of wild edible mushrooms from Lesvos is quite safe for human health. Copyright © 2011 Elsevier

  14. Whole rock and spinel compositions of serpentinized peridotites from the Divriği-Sivas region, eastern Turkey: Implications for their tectonic setting (United States)

    Ünlü, Taner; Akıska, Sinan; Varol, Ece; Öztürk, Ceyda; Mutlu, Halim


    In this study we investigate the spinel and whole rock chemistry of ultramafic rocks in the Divriği-Sivas region hosting one of the largest ophiolite suites in Turkey, which were emplaced following the convergence between the African and Eurasian plates in the Late Cretaceous. The ophiolitic mélange (Güneş Ophiolite) in Divriği is composed of ultramafic rocks, amphibolites, sub-ophiolitic metamorphic rocks and calc-silicates. The ultramafic rock section is made up of serpentinized wehrlites overlain by irregular segregations of pyroxenite levels. Whole rock chemistry of Divriği wehrlites resembles serpentinized peridotites in Himalayas. They have high MgO (average 31.27 wt%) and low Al2O3 (average 0.56 wt%) concentrations and Mg/Si and Al/Si ratios imply that peridotites formed in a supra-subduction zone environment. The U-shaped REE patterns of serpentinized wehrlites are formed by partial melting, coupled with interaction between peridotite and hydrous melts in the mantle wedge. The spinels collected from serpentinized wehrlites show compositions ranging from chromite in the core to ferritchromite and Cr-magnetite at the rims and have high Cr2O3 (46.5-56.2 wt%) and very low TiO2 contents (%35). Parental melt compositions computed (8.69-11.71 wt% for Al2O3 and 0.1 to 0.37 wt% for TiO2) from chromite-melt equilibrium conditions yield a boninitic affinity. Our data suggest that spinels from serpentinized wehrlites in the Divriği area are similar to peridotite xenoliths from the Kamchatka arc and West Bismarck.

  15. Crystallization of high-Ca chromium garnet upon interaction of serpentine, chromite, and Ca-bearing hydrous fluid (United States)

    Chepurov, A. A.; Turkin, A. I.; Pokhilenko, N. P.


    The results of experimental modeling of the conditions of crystallization of high-Ca chromium garnets in the system serpentine-chromite-Ca-Cr-bearing hydrous fluid at a pressure of 5 GPa and temperature of 1300°C are reported. The mineral association including quantitatively predominant high-Mg olivine and diopside-rich clinopyroxene, bright-green garnet, and newly formed chrome spinel was formed. Garnet mostly crystallized around primary chromite grains and was characterized by a high concentration of CaO and Cr2O3. According to the chemical composition, garnets obtained are close to the uvarovite-pyrope varieties, which enter the composition of relatively rare natural paragenesis of garnet wehrlite. The experimental data obtained clearly show that high-Ca chromium garnets are formed in the reaction of chromite-bearing peridotite and Ca-rich fluid at high P-T parameters.

  16. Serpentine bacteria influence metal translocation and bioconcentration of Brassica juncea and Ricinus communis grown in multi-metal polluted soils

    Directory of Open Access Journals (Sweden)

    Ying eMa


    Full Text Available The aim of this study was to assess the effects of inoculation of rhizosphere or endophytic bacteria (Psychrobacter sp. SRS8 and Pseudomonas sp. A3R3, respectively isolated from a serpentine environment on the plant growth and the translocation and accumulation of Ni, Zn and Fe by Brassica juncea and Ricinus communis on a multi-metal polluted serpentine soil (SS. Field collected SS was diluted to 0, 25, 50 and 75% with pristine soil in order to obtain a range of heavy metal concentrations and used in microcosm experiments. Regardless of inoculation with bacteria, the biomass of both plant species decreased with increase of the proportion of SS. Inoculation of plants with bacteria significantly increased the plant biomass and the heavy metal accumulation compared with non-inoculated control in the presence of different proportion of SS, which was attributed to the production of plant growth promoting and/or metal mobilizing metabolites by bacteria. However, SRS8 showed a maximum increase in the biomass of the test plants grown even in the treatment of 75% SS. In turn, A3R3 showed maximum effects on the accumulation of heavy metals in both plants. Regardless of inoculation of bacteria and proportion of SS, both plant species exhibited low values of bioconcentration factor (<1 for Ni and Fe. The inoculation of both bacterial strains significantly increased the translocation factor (TF of Ni while decreasing the TF of Zn in both plant species. Besides this contrasting effect, the TFs of all metals were < 1, indicating that all studied bacteria-plant combinations are suitable for phytostabilization. This study demonstrates that the bacterial isolates A3R3 and SRS8 improved the growth of B. juncea and R. communis in SS soils and have a great potential to be used as inoculants in phytostabilization scenarios of multi-metal contaminated soils.

  17. Aeronet Solar Flux (United States)

    National Aeronautics and Space Administration — SolRad-Net (Solar Radiation Network) is an established network of ground-based sensors providing high-frequency solar flux measurements in quasi-realtime to the...

  18. Net Ecosystem Carbon Flux (United States)

    U.S. Geological Survey, Department of the Interior — Net Ecosystem Carbon Flux is defined as the year-over-year change in Total Ecosystem Carbon Stock, or the net rate of carbon exchange between an ecosystem and the...

  19. Nitrous Oxide Flux (United States)

    U.S. Geological Survey, Department of the Interior — Nitrous Oxide (N20) flux is the net rate of nitrous oxide exchange between an ecosystem and the atmosphere. Data of this variable were generated by the USGS...

  20. Flux in Tallinn

    Index Scriptorium Estoniae


    Rahvusvahelise elektroonilise kunsti sümpoosioni ISEA2004 klubiõhtu "Flux in Tallinn" klubis Bon Bon. Eestit esindasid Ropotator, Ars Intel Inc., Urmas Puhkan, Joel Tammik, Taavi Tulev (pseud. Wochtzchee). Klubiõhtu koordinaator Andres Lõo

  1. Generic flux coupling analysis


    Reimers, Arne; Goldstein, Y.; Bockmayr, A.


    htmlabstractFlux coupling analysis (FCA) has become a useful tool for aiding metabolic reconstructions and guiding genetic manipulations. Originally, it was introduced for constraint-based models of metabolic networks that are based on the steady-state assumption. Recently, we have shown that the steady-state assumption can be replaced by a weaker lattice-theoretic property related to the supports of metabolic fluxes. In this paper, we further extend our approach and develop an efficient algo...

  2. Triode for magnetic flux quanta. (United States)

    Vlasko-Vlasov, Vitalii; Colauto, Fabiano; Benseman, Timothy; Rosenmann, Daniel; Kwok, Wai-Kwong

    We designed a magnetic vortex triode using an array of closely spaced soft magnetic Py strips on top of a Nb superconducting film. The strips act similar to the grid electrode in an electronic triode, where the electron flow is regulated by the grid potential. In our case, we tune the vortex motion by the magnetic charge potential of the strip edges, using a small magnetic field rotating in the film plane. The magnetic charges emerging at the stripe edges and proportional to the magnetization component perpendicular to the edge direction, form linear potential barriers or valleys for vortex motion in the superconducting layer. We directly imaged the normal flux penetration into the Py/Nb films and observed retarded or accelerated entry of the normal vortices depending on the in-plane magnetization direction in the stripes. The observed flux behavior is explained by interactions between magnetically charged lines and magnetic monopoles of vortices similar to those between electrically charged strings and point charges. We discuss the possibility of using our design for manipulation of individual vortices in high-speed, low-power superconducting electronic circuits. This work was supported by the U.S. DOE, Office of Science, Materials Sciences and Engineering Division, and Office of BES (contract DE-AC02-06CH11357). F. Colauto thanks the Sao Paulo Research Foundation FAPESP (Grant No. 2015/06.085-3).

  3. The flux-flux correlation function for anharmonic barriers

    NARCIS (Netherlands)

    Goussev, Arseni; Schubert, Roman; Waalkens, Holger; Wiggins, Stephen


    The flux-flux correlation function formalism is a standard and widely used approach for the computation of reaction rates. In this paper we introduce a method to compute the classical and quantum flux-flux correlation functions for anharmonic barriers essentially analytically through the use of the

  4. Diabetic Emergencies (United States)

    ... Emergencies A-Z Share this! Home » Emergency 101 Diabetic Emergencies It is estimated that more than 20 ... they have it. The best way to prevent diabetic emergencies is to effectively manage the disease through ...

  5. Flux Pinning in Superconductors

    CERN Document Server

    Matsushita, Teruo


    The book covers the flux pinning mechanisms and properties and the electromagnetic phenomena caused by the flux pinning common for metallic, high-Tc and MgB2 superconductors. The condensation energy interaction known for normal precipitates or grain boundaries and the kinetic energy interaction proposed for artificial Nb pins in Nb-Ti, etc., are introduced for the pinning mechanism. Summation theories to derive the critical current density are discussed in detail. Irreversible magnetization and AC loss caused by the flux pinning are also discussed. The loss originally stems from the ohmic dissipation of normal electrons in the normal core driven by the electric field induced by the flux motion. The readers will learn why the resultant loss is of hysteresis type in spite of such mechanism. The influence of the flux pinning on the vortex phase diagram in high Tc superconductors is discussed, and the dependencies of the irreversibility field are also described on other quantities such as anisotropy of supercondu...


    Directory of Open Access Journals (Sweden)

    G. N. Lukyanov


    Full Text Available Subject of Study.We present a method for heat flux measuring with the use of polarization properties of ferroelectric ceramics. Heat flux innovative sensor is developed on the basis of the proposed method. Its experimental verification is carried out. Method. The measurements are based on maintaining a balance between the processes caused by thermal energy and the energy of the electric field in the ferroelectric ceramics. Main Results. The testing of the proposed heat flux sensor has been organized in two stages. At the first stage the primary calibration has been performed by calibrated sensors ITP MG4.03/x(y “Potok”. At the second stage the testing of heat flux sensor has been carried out for calculating the quantity of heat. The comparison of the results to the readings of serial heat meters VKT-7 and STK-15 has been performed. Experiments have shown that the polarization properties of the ferroelectric ceramics can be used to measure the heat flow. Practical Relevance. The proposed sensor can be recommended as an apartment-level heat meter. The calibration of the proposed heat flux sensor with more accurate measurement tools gives the possibility to include it on the State Register of Measuring Instruments.

  7. Flux pinning in superconductors

    CERN Document Server

    Matsushita, Teruo


    The book covers the flux pinning mechanisms and properties and the electromagnetic phenomena caused by the flux pinning common for metallic, high-Tc and MgB2 superconductors. The condensation energy interaction known for normal precipitates or grain boundaries and the kinetic energy interaction proposed for artificial Nb pins in Nb-Ti, etc., are introduced for the pinning mechanism. Summation theories to derive the critical current density are discussed in detail. Irreversible magnetization and AC loss caused by the flux pinning are also discussed. The loss originally stems from the ohmic dissipation of normal electrons in the normal core driven by the electric field induced by the flux motion. The readers will learn why the resultant loss is of hysteresis type in spite of such mechanism. The influence of the flux pinning on the vortex phase diagram in high Tc superconductors is discussed, and the dependencies of the irreversibility field are also described on other quantities such as anisotropy of supercondu...

  8. Axial flux permanent magnet brushless machines

    CERN Document Server

    Gieras, Jacek F; Kamper, Maarten J


    Axial Flux Permanent Magnet (AFPM) brushless machines are modern electrical machines with a lot of advantages over their conventional counterparts. They are being increasingly used in consumer electronics, public life, instrumentation and automation system, clinical engineering, industrial electromechanical drives, automobile manufacturing industry, electric and hybrid electric vehicles, marine vessels and toys. They are also used in more electric aircrafts and many other applications on larger scale. New applications have also emerged in distributed generation systems (wind turbine generators

  9. Conditions of stichtite (Mg6Cr2(OH)16[CO3]·4H2O) formation and its geochemical and isotope record of early phanerozoic serpentinizing environments (United States)

    Melchiorre, Erik B.; Bottrill, Ralph; Huss, Gary R.; Lopez, Amanda


    Stichtite is a magnesium-chromium hydroxycarbonate mineral found in association with early Phanerozoic chromite-rich serpentinite rocks of Tasmania, Australia and Tehuitzingo, Mexico. Elemental analysis of stichtite shows a range of compositions within the Cr-Fe-Al hydrotalcite group, with compositional trends associated with each discrete serpentinite host body. Elemental and textural analysis of stichtite-associated chromite indicates that stichtite forms in fore-arc setting rocks through interaction of chromite and methane-rich serpentinizing fluids. The degree to which chromite is replaced by stichtite is inferred to correlate with the length of time that the host rocks spent within the ;stichtite window.; Carbon stable-isotope analyses of stichtite suggest carbon sourcing from marine kerogen with a minor marine carbonate component in some samples. The carbon and hydrogen stable isotope profile of stichtite ranges from the field of methane from active serpentinizing zones, to organic thermogenic methane. The association of the stichtite 2H polytype (nee barbertonite) with aragonite ± antigorite suggests this is a higher pressure/temperature polytype of stichtite. Reaction completion textures, isotopic values, and qualitative mineral thermobarometric indicators indicate that stichtite forms during serpentinization of fore-arc setting rocks in a methane/H2-rich environment within fluid conduits, ranging from low temperatures and pressures near the surface, to depths where pressure is up to 0.8-1.2 GPa and temperature is up to ∼300 °C. These unique chemical, isotopic, and textural properties of stichtite from distinct serpentinite bodies likely record the duration of serpentinization at specific thermobarometric conditions, and provide a window into the conditions associated with a potentially habitable environment on early Earth and other bodies of the solar system.

  10. Dislocation Reduction and Stress Relaxation of GaN and InGaN Multiple Quantum Wells with Improved Performance via Serpentine Channel Patterned Mask. (United States)

    Ji, Qingbin; Li, Lei; Zhang, Wei; Wang, Jia; Liu, Peichi; Xie, Yahong; Yan, Tongxing; Yang, Wei; Chen, Weihua; Hu, Xiaodong


    The existence of high threading dislocation density (TDD) in GaN-based epilayers is a long unsolved problem, which hinders further applications of defect-sensitive GaN-based devices. Multiple-modulation of epitaxial lateral overgrowth (ELOG) is used to achieve high-quality GaN template on a novel serpentine channel patterned sapphire substrate (SCPSS). The dislocation blocking brought by the serpentine channel patterned mask, coupled with repeated dislocation bending, can reduce the dislocation density to a yet-to-be-optimized level of ∼2 × 10(5) to 2 × 10(6) cm(-2). About 80% area utilization rate of GaN with low TDD and stress relaxation is obtained. The periodical variations of dislocation density, optical properties and residual stress in GaN-based epilayers on SCPSS are analyzed. The quantum efficiency of InGaN/GaN multiple quantum wells (MQWs) on it can be increased by 52% compared with the conventional sapphire substrate. The reduced nonradiative recombination centers, the enhanced carrier localization, and the suppressed quantum confined Stark effect, are the main determinants of improved luminous performance in MQWs on SCPSS. This developed ELOG on serpentine shaped mask needs no interruption and regrowth, which can be a promising candidate for the heteroepitaxy of semipolar/nonpolar GaN and GaAs with high quality.

  11. Methane: Fuel or Exhaust at the Emergence of Life? (United States)

    Russell, Michael J.; Nitschke, Wolfgang


    As many of the methanogens first encountered at hydrothermal vents were thermophilic to hyperthermophilic and comprised one of the lower roots of the evolutionary tree, it has been assumed that methanogenesis was one of the earliest, if not the earliest, pathway to life. It being well known that hydrothermal springs associated with serpentinization also bore abiotic methane, it had been further assumed that emergent biochemistry merely adopted and quickened this supposed serpentinization reaction. Yet, recent hydrothermal experiments simulating serpentinization have failed to generate methane so far, thus casting doubt on this assumption. The idea that the inverse view is worthy of debate, that is, that methanotrophy was the earlier, is stymied by the "fact" that methanotrophy itself has been termed "reverse methanogenesis," so allotting the methanogens the founding pedigree. Thus, attempting to suggest instead that methanogenesis might be termed reverse methanotrophy would require "unlearning" - a challenge to the subconscious! Here we re-examine the "impossibility" of methanotrophy predating methanogenesis as in what we have termed the "denitrifying methanotrophic acetogenic pathway." Advantages offered by such thinking are that methane would not only be a fuel but also a ready source of reduced carbon to combine with formate or carbon monoxide - available in hydrothermal fluids - to generate acetate, a target molecule of the first autotrophs. And the nitrate/nitrite required for the putative oxidation of methane with activated NO would also be a ready source of fixed nitrogen for amination reactions. Theoretical conditions for such a putative pathway would be met in a hydrothermal green rust-bearing exhalative pile and associated chimneys subject to proton and electron counter gradients. This hypothesis could be put to test in a high-pressure hydrothermal reaction chamber in which a cool carbonate/nitrate/nitrite-bearing early acidulous ocean simulant is

  12. Generic flux coupling analysis

    NARCIS (Netherlands)

    A.C. Reimers (Arne); Y. Goldstein; A. Bockmayr


    htmlabstractFlux coupling analysis (FCA) has become a useful tool for aiding metabolic reconstructions and guiding genetic manipulations. Originally, it was introduced for constraint-based models of metabolic networks that are based on the steady-state assumption. Recently, we have shown that the

  13. Flux Vacua and Supermanifolds

    CERN Document Server

    Grassi, P A


    As been recently pointed out, physically relevant models derived from string theory require the presence of non-vanishing form fluxes besides the usual geometrical constraints. In the case of NS-NS fluxes, the Generalized Complex Geometry encodes these informations in a beautiful geometrical structure. On the other hand, the R-R fluxes call for supergeometry as the underlying mathematical framework. In this context, we analyze the possibility of constructing interesting supermanifolds recasting the geometrical data and RR fluxes. To characterize these supermanifolds we have been guided by the fact topological strings on supermanifolds require the super-Ricci flatness of the target space. This can be achieved by adding to a given bosonic manifold enough anticommuting coordinates and new constraints on the bosonic sub-manifold. We study these constraints at the linear and non-linear level for a pure geometrical setting and in the presence of p-form field strengths. We find that certain spaces admit several supe...

  14. Soluble organic nutrient fluxes (United States)

    Robert G. Qualls; Bruce L. Haines; Wayne Swank


    Our objectives in this study were (i) compare fluxes of the dissolved organic nutrients dissolved organic carbon (DOC), DON, and dissolved organic phosphorus (DOP) in a clearcut area and an adjacent mature reference area. (ii) determine whether concentrations of dissolved organic nutrients or inorganic nutrients were greater in clearcut areas than in reference areas,...

  15. Generic flux coupling analysis. (United States)

    Reimers, Arne C; Goldstein, Yaron; Bockmayr, Alexander


    Flux coupling analysis (FCA) has become a useful tool for aiding metabolic reconstructions and guiding genetic manipulations. Originally, it was introduced for constraint-based models of metabolic networks that are based on the steady-state assumption. Recently, we have shown that the steady-state assumption can be replaced by a weaker lattice-theoretic property related to the supports of metabolic fluxes. In this paper, we further extend our approach and develop an efficient algorithm for generic flux coupling analysis that works with any kind of qualitative pathway model. We illustrate our method by thermodynamic flux coupling analysis (tFCA), which allows studying steady-state metabolic models with loop-law thermodynamic constraints. These models do not satisfy the lattice-theoretic properties required in our previous work. For a selection of genome-scale metabolic network reconstructions, we discuss both theoretically and practically, how thermodynamic constraints strengthen the coupling results that can be obtained with classical FCA. A prototype implementation of tFCA is available at Copyright © 2015 Elsevier Inc. All rights reserved.

  16. Reuse of spent FCC catalyst, waste serpentine and kiln rollers waste for synthesis of cordierite and cordierite-mullite ceramics. (United States)

    Ramezani, A; Emami, S M; Nemat, S


    Spent fluid catalytic cracking (FCC) was gathered from several petrochemical plants and calcined in a rotary furnace between 1000 and 1100°C in order to remove sulphur and hydrocarbon based impurities. Calcining process on FCC led to formation of AlVO4 ceramic phase, so converted the hazardous waste to non-hazardous applicable raw material. In this study, two ceramic bodies as cordierite and cordierite-mullite were synthesized with calcined spent FCC, waste serpentine, kiln rollers waste and high grade kaolin as raw materials. The XRD results showed that the cordierite and cordierite-mullite were synthesized successfully so that 96.4% of F1 (cordierite) sample fired at 1400°C was cordierite phase and F2 (cordierite-mullite) sample fired at 1450°C was completely cordierite and mullite phases. The synthesized cordierite and cordierite-mullite samples had lower porosity values and coefficient of thermal expansion (CTE) than similar industrial products. The negative CTE value that obtained from the cordierite sample up to 800°C is favorable for some applications. The considerable results of the synthesized cordierite and cordierite-mullite from this work present cost reduction of the two ceramic bodies production and may help to solve the environmental problems with the use of three waste sources in large scales. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. Long-term evaluation of a 10-liter serpentine-type microbial fuel cell stack treating brewery wastewater. (United States)

    Zhuang, Li; Yuan, Yong; Wang, Yueqiang; Zhou, Shungui


    A 10-liter serpentine-type microbial fuel cell (MFC) stack was constructed by extending 40 tubular air-cathode MFC units in a 3-D alignment pattern. When operated in series and fed with brewery wastewater, the stack produced an open circuit voltage of 23.0V and a maximum power density of 4.1W/m(3) (at 0.7A/m(3)). During long-term performance (180days), electrochemical tests were conducted to explore the reasons for deterioration in performance of the stack system. Cyclic voltammetric measurements suggested that the cathodes, not the anodes, were responsible for the decrease in performance over time. After the cathode surface was rinsed with water, the power density produced by the stack system fully recovered instantaneously, due to the decrease in cathode alkalization and increase in humidity of the cathode side. This study provided an optimal configuration of a MFC stack for MFC scale-up towards large-scale applications. Copyright © 2012 Elsevier Ltd. All rights reserved.

  18. Effect of rheo-diecast process on the mechanical properties of A390 alloy by serpentine channel (United States)

    Ri, Kunhyok; Mao, Wei-min; Zheng, Zhi-kai; Kim, Myongsik; Sin, Yongho


    In this paper, the effects of rheo-diecast process parameters and T6 heat treatment on the microstructure and mechanical properties of the rheo-diecasting (RDC) semi-solid A390 alloy prepared through pure copper serpentine channel were investigated. The results indicate that the mechanical properties of the RDC samples change with the pouring temperature and injection pressure. In this case, a lower pouring temperature results in better tensile strength and elongation of the RDC A390 alloy; however, the tensile strength and elongation decrease when the pouring temperature decreases to 660°C. Higher injection pressures result in the improved mechanical properties of the RDC A390 alloy. To some extent, T6 heat treatment improves the tensile strength and ductility of the RDC A390 alloy compared to those of the non-heat treated alloy. However, when the pouring temperature and injection pressure are greater than 670°C and 70 MPa, respectively, the mechanical properties are sharply diminished.

  19. A Novel AP2/ERF Transcription Factor CR1 Regulates the Accumulation of Vindoline and Serpentine in Catharanthus roseus

    Directory of Open Access Journals (Sweden)

    Jiaqi Liu


    Full Text Available As one type of the most important alkaloids in the world, terpenoid indole alkaloids (TIAs show a wide range of pharmaceutical activities that are beneficial for clinical treatments. Catharanthus roseus produces approximately 130 identified TIAs and is considered to be a model plant to study TIA biosynthesis. In order to increase the production of high medical value metabolites whose yields are extremely low in C. roseus, genetic engineering combined with transcriptional regulation has been applied in recent years. By using bioinformatics which is based on RNA sequencing (RNA-seq data from methyl jasmonate (MeJA-treated C. roseus as well as phylogenetic analysis, the present work aims to screen candidate genes that may be involved in the regulation of TIA biosynthesis, resulting in a novel AP2/ERF transcription factor, CR1 (Catharanthus roseus 1. Subsequently, virus-induced gene silencing (VIGS of CR1 was carried out to identify the involvement of CR1 in the accumulations of several TIAs and quantitative real-time PCR (qRT-PCR was then applied to detect the expression levels of 7 genes in the related biosynthetic pathway in silenced plants. The results show that all the 7 genes were upregulated in CR1-silenced plants. Furthermore, metabolite analyses indicate that silencing CR1 could increase the accumulations of vindoline and serpentine in C. roseus. These results suggest a novel negative regulator which may be involved in the TIAs biosynthetic pathway.

  20. A Novel AP2/ERF Transcription Factor CR1 Regulates the Accumulation of Vindoline and Serpentine in Catharanthus roseus. (United States)

    Liu, Jiaqi; Gao, Fangyuan; Ren, Juansheng; Lu, Xianjun; Ren, Guangjun; Wang, Rui


    As one type of the most important alkaloids in the world, terpenoid indole alkaloids (TIAs) show a wide range of pharmaceutical activities that are beneficial for clinical treatments. Catharanthus roseus produces approximately 130 identified TIAs and is considered to be a model plant to study TIA biosynthesis. In order to increase the production of high medical value metabolites whose yields are extremely low in C. roseus, genetic engineering combined with transcriptional regulation has been applied in recent years. By using bioinformatics which is based on RNA sequencing (RNA-seq) data from methyl jasmonate (MeJA)-treated C. roseus as well as phylogenetic analysis, the present work aims to screen candidate genes that may be involved in the regulation of TIA biosynthesis, resulting in a novel AP2/ERF transcription factor, CR1 (Catharanthus roseus 1). Subsequently, virus-induced gene silencing (VIGS) of CR1 was carried out to identify the involvement of CR1 in the accumulations of several TIAs and quantitative real-time PCR (qRT-PCR) was then applied to detect the expression levels of 7 genes in the related biosynthetic pathway in silenced plants. The results show that all the 7 genes were upregulated in CR1-silenced plants. Furthermore, metabolite analyses indicate that silencing CR1 could increase the accumulations of vindoline and serpentine in C. roseus. These results suggest a novel negative regulator which may be involved in the TIAs biosynthetic pathway.

  1. Emergent geometry, emergent forces (United States)

    Selesnick, S. A.


    We give a brief account of some aspects of Finkelstein’s quantum relativity, namely an extension of it that derives elements of macroscopic geometry and the Lagrangians of the standard model including gravity from a presumed quantum version of spacetime. These emerge as collective effects in this quantal substrate. Our treatment, which is largely self-contained, differs mathematically from that originally given by Finkelstein. Dedicated to the memory of David Ritz Finkelstein

  2. Emergency contraception (United States)

    Morning-after pill; Postcoital contraception; Birth control - emergency; Plan B; Family planning - emergency contraception ... Emergency contraception most likely prevents pregnancy in the same way as regular birth control pills: By preventing ...

  3. Exploring the Flux Tube Paradigm in Solar-like Convection Zones (United States)

    Weber, Maria A.; Nelson, Nicholas; Browning, Matthew


    In the solar context, important insight into the flux emergence process has been obtained by assuming the magnetism giving rise to sunspots consists partly of idealized flux tubes. Global-scale dynamo models are only now beginning to capture some aspects of flux emergence. In certain regimes, these simulations self-consistently generate magnetic flux structures that rise buoyantly through the computational domain. How similar are these dynamo-generated, rising flux structures to traditional flux tube models? The work we present here is a step toward addressing this question. We utilize the thin flux tube (TFT) approximation to simply model the evolution of flux tubes in a global, three-dimensional geometry. The TFTs are embedded in convective flows taken from a global dynamo simulation of a rapidly rotating Sun within which buoyant flux structures arise naturally from wreaths of magnetism. The initial conditions of the TFTs are informed by rising flux structures identified in the dynamo simulation. We compare the trajectories of the dynamo-generated flux loops with those computed through the TFT approach. We also assess the nature of the relevant forces acting on both sets of flux structures, such as buoyancy, the Coriolis force, and external forces imparted by the surrounding convection. To achieve the fast Law trend of active regions. Our work aims to provide constraints, and possible calibrations, on the traditional flux tube model as it pertains to the Sun and other spotted stars.

  4. Ophthalmic emergencies. (United States)

    Mandell, Deborah C; Holt, Elaine


    Ophthalmic emergencies are common presenting complaints in an emergency room. Most ophthalmic emergencies can be treated and stabilized until an ophthalmologist can be consulted. Most ocular emergencies involve loss of vision, compromised globe integrity, or severe ocular pain. Delay in treating true emergencies may result ina blind eye or loss of an eye. This article discusses the clinical signs,diagnosis, and treatment as well as the prognosis of some of the more common ophthalmic emergencies.

  5. Entrepreneurship, Emerging Technologies, Emerging Markets

    NARCIS (Netherlands)

    Thukral, Inderpreet S.; Von Ehr, James; Walsh, Steven Thomas; Groen, Arend J.; van der Sijde, Peter; Adham, Khairul Akmaliah


    Academics and practitioners alike have long understood the benefits, if not the risks, of both emerging markets and emerging technologies.Yet it is only recently that foresighted firms have embraced emerging technologies and emerging markets through entrepreneurial activity. Emerging technologies

  6. Atmospheric lepton fluxes

    Directory of Open Access Journals (Sweden)

    Gaisser Thomas K.


    Full Text Available This review of atmospheric muons and neutrinos emphasizes the high energy range relevant for backgrounds to high-energy neutrinos of astrophysical origin. After a brief historical introduction, the main distinguishing features of atmospheric νμ and νe are discussed, along with the implications of the muon charge ratio for the νµ / ν̅µ ratio. Methods to account for effects of the knee in the primary cosmic-ray spectrum and the energy-dependence of hadronic interactions on the neutrino fluxes are discussed and illustrated in the context of recent results from IceCube. A simple numerical/analytic method is proposed for systematic investigation of uncertainties in neutrino fluxes arising from uncertainties in the primary cosmic-ray spectrum/composition and hadronic interactions.

  7. Hibridación de medios en la confluencia de forma, tiempo y espacio: de la Danse Serpentine al Capturing Dance = Hybridization of artistic media on the crossroad of Shape, Time and Space: from Danse Serpentine to Capturing Dance

    Directory of Open Access Journals (Sweden)

    Clara Laguillo Abbad


    Full Text Available Los hermanos Lumière registraron la Danse Serpentine de Loïe Fuller en 1896. Mediante el movimiento de sus telas, Fuller investigaba la luz teatral. Y a través del registro y posterior tinte de sus fotogramas, los Lumière inauguraban el lenguaje cinematográfico. Así pues, cabe decir que ya en el siglo XIX, lo performativo y su registro iban de la mano.En mayo de 2011 las artistas pluridisciplinares Merche Blasco, Mimi Yin y Christine Doempke, presentaban en la Tisch School of the Arts de la NYU 'Capturing Dance – Exploring movement with computer vision'. Se trataba de Una propuesta que incluía un dispositivo que funcionaba con tecnología kinect, que registraba la interacción entre el dispositivo y los bailarines, la audiencia y la música, además de generar modificaciones en los movimientos propuestos.La dos propuestas, con más de cien años de diferencia entre ellas, desvelan sin embargo inquietudes compartidas: el interés por la naturaleza móvil del arte; por el cuerpo y sus limites; por la tensión efímero-permanente; por la mediación como lugar de reflexión; y finalmente, ambas introducen lo último de la tecnología de su momento.In 1896 the Lumière Brothers registered Loïe Fuller's Danse Serpentine. Through the cloths' movement, Fuller was exploring theatrical light. And through cinematographic recording and postproduction -tinting frames one by one, the Lumière Brothers started film language. Therefore in the 19th century artistic performance and its recording went hand in hand.In May 2011, the multidisciplinary artists Merche Blasco, Mimi Yin and Christine Doempke, presented at the NYU Tisch School of the Arts "Capturing Dance – Exploring movement with computer vision". The artistic project included a device that worked with kinect technology, which  captured the interaction between the device and the dancers, the audience and the music, and also generated modifications in the

  8. Reactor flux calculations

    Energy Technology Data Exchange (ETDEWEB)

    Lhuillier, D. [Commissariat à l' Énergie Atomique et aux Énergies Alternatives, Centre de Saclay, IRFU/SPhN, 91191 Gif-sur-Yvette (France)


    The status of the prediction of reactor anti-neutrino spectra is presented. The most accurate method is still the conversion of total β spectra of fissionning isotopes as measured at research reactors. Recent re-evaluations of the conversion process led to an increased predicted flux by few percent and were at the origin of the so-called reactor anomaly. The up to date predictions are presented with their main sources of error. Perspectives are given on the complementary ab-initio predictions and upcoming experimental cross-checks of the predicted spectrum shape.

  9. Serpentine Ultralong Path with Extended Routing (SUPER) High Resolution Traveling Wave Ion Mobility-MS using Structures for Lossless Ion Manipulations

    Energy Technology Data Exchange (ETDEWEB)

    Deng, Liulin; Webb, Ian K.; Garimella, Venkata BS; Hamid, Ahmed M.; Zheng, Xueyun; Norheim, Randolph V.; Prost, Spencer A.; Anderson, Gordon A.; Sandoval, Jeremy A.; Baker, Erin M.; Ibrahim, Yehia M.; Smith, Richard D.


    Ion mobility (IM) separations have a broad range of analytical applications, but insufficient resolution limits many applications. Here we report on traveling wave (TW) ion mobility (IM) separations in a Serpentine Ultra-long Path with Extended Routing (SUPER) Structures for Lossless Ion Manipulations (SLIM) module in conjunction with mass spectrometry (MS). The extended routing utilized multiple passes was facilitated by the introduction of a lossless ion switch at the end of the ion path that either directed ions to the MS detector or to another pass through the serpentine separation region, providing theoretically unlimited TWIM path lengths. Ions were confined in the SLIM by rf fields in conjunction with a DC guard bias, enabling essentially lossless TW transmission over greatly extended paths (e.g., ~1094 meters over 81 passes through the 13.5 m serpentine path). In this multi-pass SUPER TWIM provided resolution approximately proportional to the square root of the number of passes (or path length). More than 30-fold higher IM resolution for Agilent tuning mix m/z 622 and 922 ions (~340 vs. ~10) was achieved for 40 passes compared to commercially available drift tube IM and other TWIM-based platforms. An initial evaluation of the isomeric sugars Lacto-N-hexaose and Lacto-N-neohexaose showed the isomeric structures to be baseline resolved, and a new conformational feature for Lacto-N-neohexaose was revealed after 9 passes. The new SLIM SUPER high resolution TWIM platform has broad utility in conjunction with MS and is expected to enable a broad range of previously challenging or intractable separations.

  10. Serpentine Ultralong Path with Extended Routing (SUPER) High Resolution Traveling Wave Ion Mobility-MS using Structures for Lossless Ion Manipulations. (United States)

    Deng, Liulin; Webb, Ian K; Garimella, Sandilya V B; Hamid, Ahmed M; Zheng, Xueyun; Norheim, Randolph V; Prost, Spencer A; Anderson, Gordon A; Sandoval, Jeremy A; Baker, Erin S; Ibrahim, Yehia M; Smith, Richard D


    Ion mobility (IM) separations have a broad range of analytical applications, but insufficient resolution often limits their utility. Here, we report on ion mobility separations in a structures for lossless ion manipulations (SLIM) serpentine ultralong path with extended routing (SUPER) traveling wave (TW) ion mobility (IM) module in conjunction with mass spectrometry (MS). Ions were confined in the SLIM by rf fields in conjunction with a DC guard bias, enabling essentially lossless TW transmission over greatly extended paths. The extended routing utilized multiple passes (e.g., ∼1094 m over 81 passes through the 13.5 m serpentine path) and was facilitated by the introduction of a lossless ion switch that allowed ions to be directed to either the MS detector or for another pass through the serpentine separation region, allowing theoretically unlimited IM path lengths. The multipass SUPER IM-MS provided resolution approximately proportional to the square root of the number of passes (or total path length). More than 30-fold higher IM resolution (∼340 vs ∼10) for Agilent tuning mix m/z 622 and 922 ions was achieved for 40 passes compared to commercially available drift tube IM and other TWIM-based platforms. An initial evaluation of the isomeric sugars lacto-N-hexaose and lacto-N-neohexaose showed the isomeric structures to be baseline resolved, and a new conformational feature for lacto-N-neohexaose was revealed after 9 passes. The new SLIM SUPER high resolution TWIM platform has broad utility in conjunction with MS and is expected to enable a broad range of previously challenging or intractable separations.

  11. Exploring the Deep Biosphere in Ophiolite-hosted Systems: What Can Metabolic Processes in Surface Seeps Tell Us About Subsurface Ecosystems in Serpentinizing Fluids? (United States)

    Meyer-Dombard, D. R.; Cardace, D.; Woycheese, K. M.; Vallalar, B.; Casar, C.; Simon, A.; Arcilla, C. A.


    Serpentinization in the subsurface produces highly reduced, high pH fluids that provide microbial habitats. It is assumed that these deep subsurface fluids contain copious H2 and CH4 gas, little/no inorganic carbon, and limited electron acceptors. As serpentinized fluids reach the oxygenated surface environment, microbial biomes shift and organisms capable of metabolizing O2 thrive (Woycheese et al., 2015). However, the relationship of microbial communities found in surface expressions of serpentinizing fluids to the subsurface biosphere is still a target of exploration. Our work in the Zambales ophiolite (Philippines) defines surface microbial habitats with geochemistry, targeted culturing efforts, and community analysis (Cardace et al., 2015; Woycheese et al., 2015). Springs range from pH 9-11.5, and contain 0.06-2 ppm DO, 0-3.7 ppm sulfide, 30-800 ppm silica. Gases include H2 and CH4 > 10uM, CO2 > 1 mM, and trace amounts of CO. These surface data allow prediction of the subsurface metabolic landscape. For example, Cardace et al., (2015) predicted that metabolism of iron is important in both biospheres. Growth media were designed to target iron reduction yielding heterotrophic and autotrophic iron reducers at high pH. Reduced iron minerals were produced in several cultures (Casar et al., sub.), and isolation efforts are underway. Shotgun metagenomic analysis shows the metabolic capacity for methanogenesis, suggesting microbial origins for some CH4 present. The enzymes methyl coenzyme M reductase, and formylmethanofuran dehydrogenase were detected, and relative abundance increased near the near-anoxic spring source. The metagenomes indicate carbon cycling at these sites is reliant on methanogenesis, acetogenesis, sulfate reduction, and H2 and CH4 oxidation. In this tropical climate, cellulose is also a likely carbon source; cellulose degrading isolates have been obtained. These results indicate a metabolically flexible community at the surface where serpentinizing

  12. Mineralizing Filamentous Bacteria from the Prony Bay Hydrothermal Field Give New Insights into the Functioning of Serpentinization-Based Subseafloor Ecosystems. (United States)

    Pisapia, Céline; Gérard, Emmanuelle; Gérard, Martine; Lecourt, Léna; Lang, Susan Q; Pelletier, Bernard; Payri, Claude E; Monnin, Christophe; Guentas, Linda; Postec, Anne; Quéméneur, Marianne; Erauso, Gaël; Ménez, Bénédicte


    Despite their potential importance as analogs of primitive microbial metabolisms, the knowledge of the structure and functioning of the deep ecosystems associated with serpentinizing environments is hampered by the lack of accessibility to relevant systems. These hyperalkaline environments are depleted in dissolved inorganic carbon (DIC), making the carbon sources and assimilation pathways in the associated ecosystems highly enigmatic. The Prony Bay Hydrothermal Field (PHF) is an active serpentinization site where, similar to Lost City (Mid-Atlantic Ridge), high-pH fluids rich in H2 and CH4 are discharged from carbonate chimneys at the seafloor, but in a shallower lagoonal environment. This study aimed to characterize the subsurface microbial ecology of this environment by focusing on the earliest stages of chimney construction, dominated by the discharge of hydrothermal fluids of subseafloor origin. By jointly examining the mineralogy and the microbial diversity of the conduits of juvenile edifices at the micrometric scale, we find a central role of uncultivated bacteria belonging to the Firmicutes in the ecology of the PHF. These bacteria, along with members of the phyla Acetothermia and Omnitrophica, are identified as the first chimneys inhabitants before archaeal Methanosarcinales. They are involved in the construction and early consolidation of the carbonate structures via organomineralization processes. Their predominance in the most juvenile and nascent hydrothermal chimneys, and their affiliation with environmental subsurface microorganisms, indicate that they are likely discharged with hydrothermal fluids from the subseafloor. They may thus be representative of endolithic serpentinization-based ecosystems, in an environment where DIC is limited. In contrast, heterotrophic and fermentative microorganisms may consume organic compounds from the abiotic by-products of serpentinization processes and/or from life in the deeper subsurface. We thus propose that

  13. Sisyawaytii tarawaytii : sifflements serpentins et autres voix d’esprits dans le chamanisme quechua du haut Pastaza (Amazonie péruvienne)


    Gutierrez Choquevilca, Andréa-Luz


    Sisyawaytii tarawaytii : sifflements serpentins et autres voix d’esprits dans le chamanisme quechua du haut Pastaza (Amazonie péruvienne). L’article analyse les techniques d’interpellations sonores des esprits dans un répertoire de chants rituels quechua en contextes cynégétique et thérapeutique. Adoptant une perspective pragmatique, l’auteur décrit les conditions d’apprentissage du savoir rituel et focalise son attention sur un dispositif de mise en abîme de la voix des esprits dans l’énonci...

  14. Coronal and heliospheric magnetic flux circulation and its relation to open solar flux evolution (United States)

    Owens, Mathew J.; Imber, Suzanne M.; James, Matthew K.; Bunce, Emma J.; Yeoman, Timothy K.


    Abstract Solar cycle 24 is notable for three features that can be found in previous cycles but which have been unusually prominent: (1) sunspot activity was considerably greater in the northern/southern hemisphere during the rising/declining phase; (2) accumulation of open solar flux (OSF) during the rising phase was modest, but rapid in the early declining phase; (3) the heliospheric current sheet (HCS) tilt showed large fluctuations. We show that these features had a major influence on the progression of the cycle. All flux emergence causes a rise then a fall in OSF, but only OSF with foot points in opposing hemispheres progresses the solar cycle via the evolution of the polar fields. Emergence in one hemisphere, or symmetric emergence without some form of foot point exchange across the heliographic equator, causes poleward migrating fields of both polarities in one or both (respectively) hemispheres which temporarily enhance OSF but do not advance the polar field cycle. The heliospheric field observed near Mercury and Earth reflects the asymmetries in emergence. Using magnetograms, we find evidence that the poleward magnetic flux transport (of both polarities) is modulated by the HCS tilt, revealing an effect on OSF loss rate. The declining phase rise in OSF was caused by strong emergence in the southern hemisphere with an anomalously low HCS tilt. This implies the recent fall in the southern polar field will be sustained and that the peak OSF has limited implications for the polar field at the next sunspot minimum and hence for the amplitude of cycle 25. PMID:28781930

  15. Coronal and heliospheric magnetic flux circulation and its relation to open solar flux evolution. (United States)

    Lockwood, Mike; Owens, Mathew J; Imber, Suzanne M; James, Matthew K; Bunce, Emma J; Yeoman, Timothy K


    Solar cycle 24 is notable for three features that can be found in previous cycles but which have been unusually prominent: (1) sunspot activity was considerably greater in the northern/southern hemisphere during the rising/declining phase; (2) accumulation of open solar flux (OSF) during the rising phase was modest, but rapid in the early declining phase; (3) the heliospheric current sheet (HCS) tilt showed large fluctuations. We show that these features had a major influence on the progression of the cycle. All flux emergence causes a rise then a fall in OSF, but only OSF with foot points in opposing hemispheres progresses the solar cycle via the evolution of the polar fields. Emergence in one hemisphere, or symmetric emergence without some form of foot point exchange across the heliographic equator, causes poleward migrating fields of both polarities in one or both (respectively) hemispheres which temporarily enhance OSF but do not advance the polar field cycle. The heliospheric field observed near Mercury and Earth reflects the asymmetries in emergence. Using magnetograms, we find evidence that the poleward magnetic flux transport (of both polarities) is modulated by the HCS tilt, revealing an effect on OSF loss rate. The declining phase rise in OSF was caused by strong emergence in the southern hemisphere with an anomalously low HCS tilt. This implies the recent fall in the southern polar field will be sustained and that the peak OSF has limited implications for the polar field at the next sunspot minimum and hence for the amplitude of cycle 25.

  16. Emergency Contraception (United States)

    ... after unprotected sex. Often called the morning-after pill, emergency contraception pills (ECPs) are hormone pills that women ... Does It Cost? Depending on the types of pills, the emergency contraception pill costs between $10 and $80. An ...

  17. Emergency Checklist (United States)

    ... Prevention Week National Prescription Drug Take-Back Day Emergency Checklist If someone may have been poisoned, call ... may save you from a visit to the emergency room. Below is a checklist to help you ...

  18. Emergence of Twisted Magnetic Flux Related Sigmoidal Brightening ...

    Indian Academy of Sciences (India)


    corona. Thus, it is essentially favourable for the subphotospheric twist to unwind the twist and transmit it through the photosphere to the corona. Therefore, it becomes essential to make complete observational descriptions of a flare from the magnetic field changes that are taking place in different atmospheric levels of the ...

  19. Obstetrical emergencies. (United States)

    Biddle, D; Macintire, D K


    This article discusses different techniques that can be used in the diagnosis and treatment of obstetrical emergencies. Female reproductive emergencies commonly encountered by small animal practitioners include pyometra, dystocia, cesarean section, mastitis, eclampsia, uterine torsion, and uterine prolapse. A thorough knowledge of normal and abnormal reproductive behavior will aid the emergency veterinarian in successfully managing such cases. Timely diagnosis and treatment of these emergencies will often give a good outcome.

  20. Optimal fluxes and Reynolds stresses

    CERN Document Server

    Jimenez, Javier


    It is remarked that fluxes in conservation laws, such as the Reynolds stresses in the momentum equation of turbulent shear flows, or the spectral energy flux in isotropic turbulence, are only defined up to an arbitrary solenoidal field. While this is not usually significant for long-time averages, it becomes important when fluxes are modelled locally in large-eddy simulations, or in the analysis of intermittency and cascades. As an example, a numerical procedure is introduced to compute fluxes in scalar conservation equations in such a way that their total integrated magnitude is minimised. The result is an irrotational vector field that derives from a potential, thus minimising sterile flux `circuits'. The algorithm is generalised to tensor fluxes and applied to the transfer of momentum in a turbulent channel. The resulting instantaneous Reynolds stresses are compared with their traditional expressions, and found to be substantially different.

  1. Graphene thermal flux transistor. (United States)

    Shafranjuk, S E


    Insufficient flexibility of existing approaches to controlling the thermal transport in atomic monolayers limits their capability for use in many applications. Here, we examine the means of electrode doping to control the thermal flux Q due to phonons propagating along the atomic monolayer. We found that the frequency of the electron-restricted phonon scattering strongly depends on the concentration nC. of the electric charge carriers, established by the electric potentials applied to local gates. As a result of the electrode doping, nC is increased, causing a sharp rise in both the electrical conductivity and Seebeck coefficient, while the thermal conductivity tumbles. Therefore, the effect of the thermal transistor improves the figure of merit of nanoelectronic circuits.

  2. Neutron fluxes in test reactors

    Energy Technology Data Exchange (ETDEWEB)

    Youinou, Gilles Jean-Michel [Idaho National Lab. (INL), Idaho Falls, ID (United States)


    Communicate the fact that high-power water-cooled test reactors such as the Advanced Test Reactor (ATR), the High Flux Isotope Reactor (HFIR) or the Jules Horowitz Reactor (JHR) cannot provide fast flux levels as high as sodium-cooled fast test reactors. The memo first presents some basics physics considerations about neutron fluxes in test reactors and then uses ATR, HFIR and JHR as an illustration of the performance of modern high-power water-cooled test reactors.

  3. Heat Flux Instrumentation Laboratory (HFIL) (United States)

    Federal Laboratory Consortium — Description: The Heat Flux Instrumentation Laboratory is used to develop advanced, flexible, thin film gauge instrumentation for the Air Force Research Laboratory....

  4. Methane flux from wetlands areas




    Ebullient gases from Michigan wetlands have been collected and analyzed to deduce in situ methane fluxes. Methane flux has been found to be a function of mean air temperature. This relationship has been utilized to extrapolate observed methane fluxes to estimates of fluxes from the Pripet marshes, Sudd, Everglades, and Ugandan swamps. These four wetlands together provide a yearly source of 6.8 × 1013 g of methane to the atmosphere.DOI: 10.1111/j.2153-3490.1977.tb00731.x

  5. Coronal and heliospheric magnetic flux circulation and its relation to open solar flux evolution (United States)

    Lockwood, Mike; Owens, Mathew J.; Imber, Suzanne M.; James, Matthew K.; Bunce, Emma J.; Yeoman, Timothy K.


    Solar cycle 24 is notable for three features that can be found in previous cycles but which have been unusually prominent: (1) sunspot activity was considerably greater in the northern/southern hemisphere during the rising/declining phase; (2) accumulation of open solar flux (OSF) during the rising phase was modest, but rapid in the early declining phase; (3) the heliospheric current sheet (HCS) tilt showed large fluctuations. We show that these features had a major influence on the progression of the cycle. All flux emergence causes a rise then a fall in OSF, but only OSF with foot points in opposing hemispheres progresses the solar cycle via the evolution of the polar fields. Emergence in one hemisphere, or symmetric emergence without some form of foot point exchange across the heliographic equator, causes poleward migrating fields of both polarities in one or both (respectively) hemispheres which temporarily enhance OSF but do not advance the polar field cycle. The heliospheric field observed near Mercury and Earth reflects the asymmetries in emergence. Using magnetograms, we find evidence that the poleward magnetic flux transport (of both polarities) is modulated by the HCS tilt, revealing an effect on OSF loss rate. The declining phase rise in OSF was caused by strong emergence in the southern hemisphere with an anomalously low HCS tilt. This implies the recent fall in the southern polar field will be sustained and that the peak OSF has limited implications for the polar field at the next sunspot minimum and hence for the amplitude of cycle 25.Plain Language SummaryThere is growing interest in being able to predict the evolution in solar conditions on a better basis than past experience, which is necessarily limited. Two of the key features of the solar magnetic cycle are that the polar fields reverse just after the peak of each sunspot cycle and that the polar field that has accumulated by the time of each sunspot minimum is a good indicator of the amplitude

  6. Microbial diversity in a submarine carbonate edifice from the serpentinizing hydrothermal system of the Prony Bay (New Caledonia over a 6-year period.

    Directory of Open Access Journals (Sweden)

    Anne ePostec


    Full Text Available Active carbonate chimneys from the shallow marine serpentinizing Prony Hydrothermal Field were sampled 3 times over a 6 years period at site ST09. Archaeal and bacterial communities composition was investigated using PCR-based methods (clone libraries, Denaturating Gel Gradient Electrophoresis, quantitative PCR targeting 16S rRNA genes, methyl coenzyme M reductase A and dissimilatory sulfite reductase subunit B genes. Methanosarcinales (Euryarchaeota and Thaumarchaea were the main archaeal members. The Methanosarcinales, also observed by epifluorescent microscopy and FISH, consisted of two phyotypes that were previously solely detected in two other serpentinitzing ecosystems (The Cedars and Lost City Hydrothermal Field. Surprisingly, members of the hyperthermophilic order Thermococcales were also found which may indicate the presence of a hot subsurface biosphere. The bacterial community mainly consisted of Firmicutes, Chloroflexi, Alpha-, Gamma-, Beta- and Delta-proteobacteria and of the candidate division NPL-UPA2. Members of these taxa were consistently found each year and may therefore represent a stable core of the indigenous bacterial community of the PHF chimneys. Firmicutes isolates representing new bacterial taxa were obtained by cultivation under anaerobic conditions. Our study revealed diverse microbial communities in PHF ST09 related to methane and sulfur compounds that share common populations with other terrestrial or submarine serpentinizing ecosystems.

  7. Microbial diversity in a submarine carbonate edifice from the serpentinizing hydrothermal system of the Prony Bay (New Caledonia) over a 6-year period. (United States)

    Postec, Anne; Quéméneur, Marianne; Bes, Méline; Mei, Nan; Benaïssa, Fatma; Payri, Claude; Pelletier, Bernard; Monnin, Christophe; Guentas-Dombrowsky, Linda; Ollivier, Bernard; Gérard, Emmanuelle; Pisapia, Céline; Gérard, Martine; Ménez, Bénédicte; Erauso, Gaël


    Active carbonate chimneys from the shallow marine serpentinizing Prony Hydrothermal Field were sampled 3 times over a 6 years period at site ST09. Archaeal and bacterial communities composition was investigated using PCR-based methods (clone libraries, Denaturating Gel Gradient Electrophoresis, quantitative PCR) targeting 16S rRNA genes, methyl coenzyme M reductase A and dissimilatory sulfite reductase subunit B genes. Methanosarcinales (Euryarchaeota) and Thaumarchaea were the main archaeal members. The Methanosarcinales, also observed by epifluorescent microscopy and FISH, consisted of two phylotypes that were previously solely detected in two other serpentinitzing ecosystems (The Cedars and Lost City Hydrothermal Field). Surprisingly, members of the hyperthermophilic order Thermococcales were also found which may indicate the presence of a hot subsurface biosphere. The bacterial community mainly consisted of Firmicutes, Chloroflexi, Alpha-, Gamma-, Beta-, and Delta-proteobacteria and of the candidate division NPL-UPA2. Members of these taxa were consistently found each year and may therefore represent a stable core of the indigenous bacterial community of the PHF chimneys. Firmicutes isolates representing new bacterial taxa were obtained by cultivation under anaerobic conditions. Our study revealed diverse microbial communities in PHF ST09 related to methane and sulfur compounds that share common populations with other terrestrial or submarine serpentinizing ecosystems.

  8. Investigations of potential microbial methanogenic and carbon monoxide utilization pathways in ultra-basic reducing springs associated with present-day continental serpentinization: the Tablelands, NL, CAN

    Directory of Open Access Journals (Sweden)

    Penny Lea Morrill


    Full Text Available Ultra-basic reducing springs at continental sites of serpentinization act as portals into the biogeochemistry of a subsurface environment with H2 and CH4 present. Very little, however, is known about the carbon substrate utilization, energy sources, and metabolic pathways of the microorganisms that live in this ultra-basic environment. The potential for microbial methanogenesis with bicarbonate, formate, acetate, and propionate precursors and carbon monoxide (CO utilization pathways were tested in laboratory experiments by adding substrates to water and sediment from the Tablelands, NL, CAD, a site of present-day continental serpentinization. Microbial methanogenesis was not observed after bicarbonate, formate, acetate, or propionate addition. CO was consumed in the live experiments but not in the killed controls and the residual CO in the live experiments became enriched in 13 C. The average isotopic enrichment factor resulting from this microbial utilization of CO was estimated to be 11.2 ± 0.2‰. Phospholipid fatty acid concentrations and δ13C values suggest limited incorporation of carbon from CO into microbial lipids. This indicates that in our experiments, CO was used primarily as an energy source, but not for biomass growth. Environmental DNA sequencing of spring fluids collected at the same time as the addition experiments yielded a large proportion of Hydrogenophaga-related sequences, which is consistent with previous metagenomic data indicating the potential for these taxa to utilize CO.

  9. Investigations of potential microbial methanogenic and carbon monoxide utilization pathways in ultra-basic reducing springs associated with present-day continental serpentinization: the Tablelands, NL, CAN. (United States)

    Morrill, Penny L; Brazelton, William J; Kohl, Lukas; Rietze, Amanda; Miles, Sarah M; Kavanagh, Heidi; Schrenk, Matthew O; Ziegler, Susan E; Lang, Susan Q


    Ultra-basic reducing springs at continental sites of serpentinization act as portals into the biogeochemistry of a subsurface environment with H2 and CH4 present. Very little, however, is known about the carbon substrate utilization, energy sources, and metabolic pathways of the microorganisms that live in this ultra-basic environment. The potential for microbial methanogenesis with bicarbonate, formate, acetate, and propionate precursors and carbon monoxide (CO) utilization pathways were tested in laboratory experiments by adding substrates to water and sediment from the Tablelands, NL, CAD, a site of present-day continental serpentinization. Microbial methanogenesis was not observed after bicarbonate, formate, acetate, or propionate addition. CO was consumed in the live experiments but not in the killed controls and the residual CO in the live experiments became enriched in (13)C. The average isotopic enrichment factor resulting from this microbial utilization of CO was estimated to be 11.2 ± 0.2‰. Phospholipid fatty acid concentrations and δ(13)C values suggest limited incorporation of carbon from CO into microbial lipids. This indicates that in our experiments, CO was used primarily as an energy source, but not for biomass growth. Environmental DNA sequencing of spring fluids collected at the same time as the addition experiments yielded a large proportion of Hydrogenophaga-related sequences, which is consistent with previous metagenomic data indicating the potential for these taxa to utilize CO.

  10. Deep long-period earthquakes west of the volcanic arc in Oregon: evidence of serpentine dehydration in the fore-arc mantle wedge (United States)

    Vidale, John E.; Schmidt, David A.; Malone, Stephen D.; Hotovec-Ellis, Alicia J.; Moran, Seth C.; Creager, Kenneth C.; Houston, Heidi


    Here we report on deep long-period earthquakes (DLPs) newly observed in four places in western Oregon. The DLPs are noteworthy for their location within the subduction fore arc: 40–80 km west of the volcanic arc, well above the slab, and near the Moho. These “offset DLPs” occur near the top of the inferred stagnant mantle wedge, which is likely to be serpentinized and cold. The lack of fore-arc DLPs elsewhere along the arc suggests that localized heating may be dehydrating the serpentinized mantle wedge at these latitudes and causing DLPs by dehydration embrittlement. Higher heat flow in this region could be introduced by anomalously hot mantle, associated with the western migration of volcanism across the High Lava Plains of eastern Oregon, entrained in the corner flow proximal to the mantle wedge. Alternatively, fluids rising from the subducting slab through the mantle wedge may be the source of offset DLPs. As far as we know, these are among the first DLPs to be observed in the fore arc of a subduction-zone system.

  11. Squeezing Flux Out of Fat

    DEFF Research Database (Denmark)

    Gonzalez-Franquesa, Alba; Patti, Mary-Elizabeth


    Merging transcriptomics or metabolomics data remains insufficient for metabolic flux estimation. Ramirez et al. integrate a genome-scale metabolic model with extracellular flux data to predict and validate metabolic differences between white and brown adipose tissue. This method allows both metab...

  12. Earth's surface heat flux

    Directory of Open Access Journals (Sweden)

    J. H. Davies


    Full Text Available We present a revised estimate of Earth's surface heat flux that is based upon a heat flow data-set with 38 347 measurements, which is 55% more than used in previous estimates. Our methodology, like others, accounts for hydrothermal circulation in young oceanic crust by utilising a half-space cooling approximation. For the rest of Earth's surface, we estimate the average heat flow for different geologic domains as defined by global digital geology maps; and then produce the global estimate by multiplying it by the total global area of that geologic domain. The averaging is done on a polygon set which results from an intersection of a 1 degree equal area grid with the original geology polygons; this minimises the adverse influence of clustering. These operations and estimates are derived accurately using methodologies from Geographical Information Science. We consider the virtually un-sampled Antarctica separately and also make a small correction for hot-spots in young oceanic lithosphere. A range of analyses is presented. These, combined with statistical estimates of the error, provide a measure of robustness. Our final preferred estimate is 47±2 TW, which is greater than previous estimates.

  13. Emergency surgery

    DEFF Research Database (Denmark)

    Stoneham, M; Murray, D; Foss, N


    National reports recommended that peri-operative care should be improved for elderly patients undergoing emergency surgery. Postoperative mortality and morbidity rates remain high, and indicate that emergency ruptured aneurysm repair, laparotomy and hip fracture fixation are high-risk procedures...... undertaken on elderly patients with limited physiological reserve. National audits have reported variations in care quality, data that are increasingly being used to drive quality improvement through professional guidance. Given that the number of elderly patients presenting for emergency surgery is likely...

  14. Reproductive emergencies. (United States)

    Jutkowitz, L Ari


    The emergency clinician is frequently called on to manage problems relating to the female reproductive tract. Because owners sel-dom have the medical knowledge needed to differentiate normal from abnormal reproductive behaviors, they frequently look to the emergency veterinarian for guidance and information during and after parturition. For this reason, it is essential that the veterinarian have a good understanding of the normal reproductive cycle as well as the common emergencies that may occur. This article reviews the events surrounding normal parturition in the dog and cat and the reproductive emergencies seen most commonly in practice.

  15. Principal Metabolic Flux Mode Analysis. (United States)

    Bhadra, Sahely; Blomberg, Peter; Castillo, Sandra; Rousu, Juho; Wren, Jonathan


    In the analysis of metabolism, two distinct and complementary approaches are frequently used: Principal component analysis (PCA) and stoichiometric flux analysis. PCA is able to capture the main modes of variability in a set of experiments and does not make many prior assumptions about the data, but does not inherently take into account the flux mode structure of metabolism. Stoichiometric flux analysis methods, such as Flux Balance Analysis (FBA) and Elementary Mode Analysis, on the other hand, are able to capture the metabolic flux modes, however, they are primarily designed for the analysis of single samples at a time, and not best suited for exploratory analysis on a large sets of samples. We propose a new methodology for the analysis of metabolism, called Principal Metabolic Flux Mode Analysis (PMFA), which marries the PCA and stoichiometric flux analysis approaches in an elegant regularized optimization framework. In short, the method incorporates a variance maximization objective form PCA coupled with a stoichiometric regularizer, which penalizes projections that are far from any flux modes of the network. For interpretability, we also introduce a sparse variant of PMFA that favours flux modes that contain a small number of reactions. Our experiments demonstrate the versatility and capabilities of our methodology. The proposed method can be applied to genome-scale metabolic network in efficient way as PMFA does not enumerate elementary modes. In addition, the method is more robust on out-of-steady steady-state experimental data than competing flux mode analysis approaches. Matlab software for PMFA and SPMFA and data set used for experiments are available in,,, Detailed results are in Supplementary files. Supplementary data are available at

  16. Emergency Shelters

    DEFF Research Database (Denmark)

    Popovic Larsen, Olga; Lee, Daniel Sang-Hoon; Eskemose Andersen, Jørgen


    The report gives all the research, teaching, seminars carried in the duration of the shelter cluster. It concludes with proposing relevant research agendas in the field of emergency architecture......The report gives all the research, teaching, seminars carried in the duration of the shelter cluster. It concludes with proposing relevant research agendas in the field of emergency architecture...

  17. Oncologic emergencies. (United States)

    Endicott, Melissa


    Cancer can lead to emergencies either due to the primary disease, or as a result of therapy. Appropriate diagnosis and rapid treatment of these conditions can result in survival of the patient. Whether chemotherapy is implemented or not, the clinician may be presented with a patient in need of emergency stabilization. Common occurring emergencies are related to effects of the cancer, ranging from immune dysfunction due to marrow infiltration to brain herniation due to increased intracranial pressure from neoplasia. Often adverse effects secondary to chemotherapy can cause emergency situations such as sepsis. Prompt diagnosis and treatment may result in a favorable outcome. Addressed in this chapter are commonly occurring emergencies and specific stabilizing treatments.

  18. Magnetic flux generation and transport in cool stars (United States)

    Işık, E.; Schmitt, D.; Schüssler, M.


    Context. The Sun and other cool stars harbouring outer convection zones manifest magnetic activity in their atmospheres. The connection between this activity and the properties of a deep-seated dynamo generating the magnetic flux is not well understood. Aims: By employing physical models, we study the spatial and temporal characteristics of the observable surface field for various stellar parameters. Methods: We combine models for magnetic flux generation, buoyancy instability, and transport, which encompass the entire convection zone. The model components are: (i) a thin-layer αΩ dynamo at the base of the convection zone; (ii) buoyancy instabilities and the rise of flux tubes through the convection zone in 3D, which provides a physically consistent determination of emergence latitudes and tilt angles; and (iii) horizontal flux transport at the surface. Results: For solar-type stars and rotation periods longer than about 10 days, the latitudinal dynamo waves generated by the deep-seated αΩ dynamo are faithfully reflected by the surface distribution of magnetic flux. For rotation periods of the order of two days, however, Coriolis acceleration of rising flux loops leads to surface flux emergence at much higher latitudes than the dynamo waves at the bottom of the convection zone reach. A similar result is found for a K0V star with a rotation period of two days. In the case of a rapidly rotating K1 subgiant, overlapping dynamo waves lead to noisy activity cycles and mixed-polarity fields at high latitudes. Conclusions: The combined model reproduces the basic observed features of the solar cycle. The differences between the latitude distributions of the magnetic field at the bottom of the convection zone and the emerging surface flux grow with increasing rotation rate and convection zone depth, becoming quite substantial for rapidly rotating dwarfs and subgiants. The dynamical evolution of buoyantly rising magnetic flux should be considered as an essential

  19. Accretionary wedge harzburgite serpentinization and rodingitization constrained by perovskite U/Pb SIMS age, trace elements and Sm/Nd isotopes: Case study from the Western Carpathians, Slovakia (United States)

    Li, Xian-Hua; Putiš, Marián; Yang, Yue-Heng; Koppa, Matúš; Dyda, Marian


    Perovskite-bearing harzburgites occur in a “mélange” type blueschist-bearing accretionary wedge complex of the Inner Western Carpathians Meliata Unit in Slovakia. Although dark rounded, slightly hydrated relic “cores” of harzburgite boulders are perovskite-free, perovskite (Prv) occurrence in the surrounding serpentinites and rodingites enabled dating of hydration, resulting in two metamorphic-metasomatic Prv generations. Perovskite (1) grows parallel to relic clinopyroxene exsolution lamellae or forms randomly oriented grain clusters in serpentinized orthopyroxene (Opx1) porphyroclasts, often accompanied by tiny andradite lamellae clusters, or it is partly replaced by Ti-andradite. Perovskite crystallization indicates evolving rodingitization fluids pervading the boundary between the harzburgite “cores” and Prv-free serpentinite. This strictly limited occurrence of Prv (1) within a 1 to 20-cm across-zone implies slightly postponed Prv crystallization to serpentinization by LREE(Ce,La), Ca2+, Ti/Fe3+-enriched aqueous fluids. A grain scale metasomatic mechanism partitioned Ca and Ti from the host orthopyroxene porphyroclasts, spinel (Ti) and grain-boundary pervasive fluids to Prv. In contrast, Prv (2) occurs in a 1 to 3 cm across chlorite-rich blackwall zone between hosting serpentinite and rodingite veins, thus indicating channelled rodingitization fluid flow and accompanying hydraulic fracturing. Here, Prv (2) is ingrown by chlorite and apatite. Part of this Prv (2) formed in a rodingite vein mineral assemblage composed of diopside, andradite, vesuvianite, epidote/zoisite, apatite and chlorite. Both perovskite 1 and 2 are replaced by pyrophanite along the grain rims and interiors; most likely via fluid-aided coupled dissolution-reprecipitation at increased Si-Fe-Mn-Al element solubility in rodingitization fluids pervading serpentinized harzburgite. Both Prv generations, especially Prv (2), can be partly to almost totally replaced by (Ti-) Adr

  20. Studying Emerge

    DEFF Research Database (Denmark)

    Davies, Sarah Rachael; Selin, Cynthia; Rodegher, Sandra


    The Emerge event, held in Tempe, AZ in March 2012, brought together a range of scientists, artists, futurists, engineers and students in order to experiment with innovative methods for thinking about the future. These methodological techniques were tested through nine workshops, each of which made...... use of a different format; Emerge as a whole, then, offered an opportunity to study a diverse set of future-oriented engagement practices. We conducted an event ethnography, in which a team of 11 researchers collaboratively developed accounts of the practices at play within Emerge and its workshops...

  1. Conical electromagnetic radiation flux concentrator (United States)

    Miller, E. R.


    Concentrator provides method of concentrating a beam of electromagnetic radiation into a smaller beam, presenting a higher flux density. Smaller beam may be made larger by sending radiation through the device in the reverse direction.

  2. High Flux Isotope Reactor (HFIR) (United States)

    Federal Laboratory Consortium — The HFIR at Oak Ridge National Laboratory is a light-water cooled and moderated reactor that is the United States’ highest flux reactor-based neutron source. HFIR...

  3. Specification of ROP flux shape

    Energy Technology Data Exchange (ETDEWEB)

    Min, Byung Joo [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of); Gray, A. [Atomic Energy of Canada Ltd., Chalk River, ON (Canada)


    The CANDU 9 480/SEU core uses 0.9% SEU (Slightly Enriched Uranium) fuel. The use f SEU fuel enables the reactor to increase the radial power form factor from 0.865, which is typical in current natural uranium CANDU reactors, to 0.97 in the nominal CANDU 9 480/SEU core. The difference is a 12% increase in reactor power. An additional 5% increase can be achieved due to a reduced refuelling ripple. The channel power limits were also increased by 3% for a total reactor power increase of 20%. This report describes the calculation of neutron flux distributions in the CANDU 9 480/SEU core under conditions specified by the C and I engineers. The RFSP code was used to calculate of neutron flux shapes for ROP analysis. Detailed flux values at numerous potential detector sites were calculated for each flux shape. (author). 6 tabs., 70 figs., 4 refs.

  4. Physics of Magnetic Flux Ropes

    CERN Document Server

    Priest, E R; Lee, L C


    The American Geophysical Union Chapman Conference on the Physics of Magnetic Flux Ropes was held at the Hamilton Princess Hotel, Hamilton, Bermuda on March 27–31, 1989. Topics discussed ranged from solar flux ropes, such as photospheric flux tubes, coronal loops and prominences, to flux ropes in the solar wind, in planetary ionospheres, at the Earth's magnetopause, in the geomagnetic tail and deep in the Earth's magnetosphere. Papers presented at that conference form the nucleus of this book, but the book is more than just a proceedings of the conference. We have solicited articles from all interested in this topic. Thus, there is some material in the book not discussed at the conference. Even in the case of papers presented at the conference, there is generally a much more detailed and rigorous presentation than was possible in the time allowed by the oral and poster presentations.

  5. Global Intercomparison of 12 Land Surface Heat Flux Estimates (United States)

    Jimenez, C.; Prigent, C.; Mueller, B.; Seneviratne, S. I.; McCabe, M. F.; Wood, E. F.; Rossow, W. B.; Balsamo, G.; Betts, A. K.; Dirmeyer, P. A.; hide


    A global intercomparison of 12 monthly mean land surface heat flux products for the period 1993-1995 is presented. The intercomparison includes some of the first emerging global satellite-based products (developed at Paris Observatory, Max Planck Institute for Biogeochemistry, University of California Berkeley, University of Maryland, and Princeton University) and examples of fluxes produced by reanalyses (ERA-Interim, MERRA, NCEP-DOE) and off-line land surface models (GSWP-2, GLDAS CLM/ Mosaic/Noah). An intercomparison of the global latent heat flux (Q(sub le)) annual means shows a spread of approx 20 W/sq m (all-product global average of approx 45 W/sq m). A similar spread is observed for the sensible (Q(sub h)) and net radiative (R(sub n)) fluxes. In general, the products correlate well with each other, helped by the large seasonal variability and common forcing data for some of the products. Expected spatial distributions related to the major climatic regimes and geographical features are reproduced by all products. Nevertheless, large Q(sub le)and Q(sub h) absolute differences are also observed. The fluxes were spatially averaged for 10 vegetation classes. The larger Q(sub le) differences were observed for the rain forest but, when normalized by mean fluxes, the differences were comparable to other classes. In general, the correlations between Q(sub le) and R(sub n) were higher for the satellite-based products compared with the reanalyses and off-line models. The fluxes were also averaged for 10 selected basins. The seasonality was generally well captured by all products, but large differences in the flux partitioning were observed for some products and basins.

  6. Timing of fluid seepage on summits of Quaker and Conical serpentine mud volcanoes, Mariana forearc: Evidence from U/Th dating of carbonate chimneys (United States)

    Tong, Hongpeng; Fryer, Patricia; Feng, Dong; Chen, Duofu


    Serpetinization of forearc mantle along deep faults in the Mariana convergent plate margin permits formation of large active serpentinite mud volcanoes on the overiding plate within 90 km of the trench. Fluid seepage on summits of the mud volcanoes lead to the formation of authigenic carbonate chimneys close to the seafloor. Such carbonate chimneys are unique archives of past fluid seepage and assciated envrionemtnal parameters. Here, we report U/Th dating and stable carbon and oxygen isotopes of the chimneys from Quaker and Conical serpentine mud volcanoes. The resulting U/Th ages of samples from Quaker Seamount show three time intervals of 11,081 to10,542 yBP, 5,857 to 5,583 yBP, and 781 to 164 yBP, respectively. By comparison, carbonates from Conical Seamount have U/Th ages between 3,070 yBP and 1,623 yBP. Our results suggest that fluid seepage on the summits of serpentine mud volcanoes are episodic and probably locally controlled. Samples from Quaker seamount show depletion of 13C (δ13C=-7.0-0.4‰ V-PDB), indicating contribution of carbon from anoxic oxidation of abiogenic methane. By contrast, samples from Conical seamount have positive δ18O values (0.6-6.3), suggesting enrichment of 18O in the seepage fluid. The data obtained provide time integrated variation of seepage fluids and seepage dynamics that are archived in authigenic carbonates. This finding adds to the ongoing multidisciplinary effort to better constrain the environment in the Mariana forearc region and to determine the locally dominant biogeochemical processes. Acknowlegment: This study was funded by the CAS (Grant No. XDB06030102).

  7. P fluxes and exotic branes

    Energy Technology Data Exchange (ETDEWEB)

    Lombardo, Davide M. [Dipartimento di Fisica, Università di Roma “La Sapienza”,Piazzale Aldo Moro 2, 00185 Roma (Italy); Riccioni, Fabio [INFN - Sezione di Roma, Dipartimento di Fisica, Università di Roma “La Sapienza”,Piazzale Aldo Moro 2, 00185 Roma (Italy); Risoli, Stefano [Dipartimento di Fisica, Università di Roma “La Sapienza”,Piazzale Aldo Moro 2, 00185 Roma (Italy); INFN - Sezione di Roma, Dipartimento di Fisica, Università di Roma “La Sapienza”,Piazzale Aldo Moro 2, 00185 Roma (Italy)


    We consider the N=1 superpotential generated in type-II orientifold models by non-geometric fluxes. In particular, we focus on the family of P fluxes, that are related by T-duality transformations to the S-dual of the Q flux. We determine the general rule that transforms a given flux in this family under a single T-duality transformation. This rule allows to derive a complete expression for the superpotential for both the IIA and the IIB theory for the particular case of a T{sup 6}/[ℤ{sub 2}×ℤ{sub 2}] orientifold. We then consider how these fluxes modify the generalised Bianchi identities. In particular, we derive a fully consistent set of quadratic constraints coming from the NS-NS Bianchi identities. On the other hand, the P flux Bianchi identities induce tadpoles, and we determine a set of exotic branes that can be consistently included in order to cancel them. This is achieved by determining a universal transformation rule under T-duality satisfied by all the branes in string theory.

  8. Flux tubes at finite temperature

    Energy Technology Data Exchange (ETDEWEB)

    Cea, Paolo [INFN, Sezione di Bari,Via G. Amendola 173, I-70126 Bari (Italy); Dipartimento di Fisica dell’Università di Bari,Via G. Amendola 173, I-70126 Bari (Italy); Cosmai, Leonardo [INFN, Sezione di Bari,Via G. Amendola 173, I-70126 Bari (Italy); Cuteri, Francesca; Papa, Alessandro [Dipartimento di Fisica, Università della Calabria & INFN-Cosenza,Ponte Bucci, cubo 31C, I-87036 Rende (Cosenza) (Italy)


    The chromoelectric field generated by a static quark-antiquark pair, with its peculiar tube-like shape, can be nicely described, at zero temperature, within the dual superconductor scenario for the QCD confining vacuum. In this work we investigate, by lattice Monte Carlo simulations of the SU(3) pure gauge theory, the fate of chromoelectric flux tubes across the deconfinement transition. We find that, if the distance between the static sources is kept fixed at about 0.76 fm ≃1.6/√σ and the temperature is increased towards and above the deconfinement temperature T{sub c}, the amplitude of the field inside the flux tube gets smaller, while the shape of the flux tube does not vary appreciably across deconfinement. This scenario with flux-tube “evaporation” above T{sub c} has no correspondence in ordinary (type-II) superconductivity, where instead the transition to the phase with normal conductivity is characterized by a divergent fattening of flux tubes as the transition temperature is approached from below. We present also some evidence about the existence of flux-tube structures in the magnetic sector of the theory in the deconfined phase.



    Renata Rajapakse


    This paper describes emergency triage. It presents the reasons for implementation of triage and its benefits. Focuses on the Manchester triage system, which is formally validated triage model in Slovenia.

  10. Emergency Response (United States)

    Information for first responders, industry, federal, state and local governments on EPA's role and available resources for response to oil spills, chemical, biological, radiological releases, and large-scale national emergencies.

  11. Emergent emotion


    O'Connell, Elaine Finbarr


    I argue that emotion is an ontologically emergent and sui generis. I argue that emotion meets both of two individually necessary and jointly sufficient conditions for ontological emergence. These are, (i) that emotion necessarily has constituent parts to which it cannot be reduced, and (ii) that emotion has a causal effect on its constituent parts (i.e. emotion demonstrates downward causation).\\ud \\ud I argue that emotion is partly cognitive, partly constituted by feelings and partly perceptu...

  12. Dermatologic emergencies

    Directory of Open Access Journals (Sweden)

    M.P. Simón Díaz


    Full Text Available Dermatologic emergencies represent about 8–20% of the diseases seen in the Emergency Department of hospitals. It is often a challenge for primary care physicians to differentiate mundane skin ailments from more serious, life threatening conditions that require immediate intervention. In this review we included the following conditions: Stevens-Johnson syndrome/toxic epidermal necrosis, pemphigus vulgaris, toxic shock syndrome, fasciitis necrotising, angioedema/urticaria, meningococcemia, Lyme disease and Rocky Mountain spotted fever.

  13. Emerging images

    KAUST Repository

    Mitra, Niloy J.


    Emergence refers to the unique human ability to aggregate information from seemingly meaningless pieces, and to perceive a whole that is meaningful. This special skill of humans can constitute an effective scheme to tell humans and machines apart. This paper presents a synthesis technique to generate images of 3D objects that are detectable by humans, but difficult for an automatic algorithm to recognize. The technique allows generating an infinite number of images with emerging figures. Our algorithm is designed so that locally the synthesized images divulge little useful information or cues to assist any segmentation or recognition procedure. Therefore, as we demonstrate, computer vision algorithms are incapable of effectively processing such images. However, when a human observer is presented with an emergence image, synthesized using an object she is familiar with, the figure emerges when observed as a whole. We can control the difficulty level of perceiving the emergence effect through a limited set of parameters. A procedure that synthesizes emergence images can be an effective tool for exploring and understanding the factors affecting computer vision techniques. © 2009 ACM.


    CERN Document Server


    IN URGENT NEED OF A DOCTOR GENEVA EMERGENCY SERVICES GENEVA AND VAUD 144 FIRE BRIGADE 118 POLICE 117 CERN FIREMEN 767-44-44 ANTI-POISONS CENTRE Open 24h/24h 01-251-51-51 Patient not fit to be moved, call family doctor, or: GP AT HOME, open 24h/24h 748-49-50 Association Of Geneva Doctors Emergency Doctors at home 07h-23h 322 20 20 Patient fit to be moved: HOPITAL CANTONAL CENTRAL 24 Micheli-du-Crest 372-33-11 ou 382-33-11 EMERGENCIES 382-33-11 ou 372-33-11 CHILDREN'S HOSPITAL 6 rue Willy-Donzé 372-33-11 MATERNITY 32 la Cluse 382-68-16 ou 382-33-11 OPHTHALMOLOGY 22 Alcide Jentzer 382-33-11 ou 372-33-11 MEDICAL CENTRE CORNAVIN 1-3 rue du Jura 345 45 50 HOPITAL DE LA TOUR Meyrin EMERGENCIES 719-61-11 URGENCES PEDIATRIQUES 719-61-00 LA TOUR MEDICAL CENTRE 719-74-00 European Emergency Call 112 FRANCE EMERGENCY SERVICES 15 FIRE BRIGADE 18 POLICE 17 CERN FIREMEN AT HOME 00-41-22-767-44-44 ANTI-POISONS CENTRE Open 24h/24h 04-72-11-69-11 All doctors ...

  15. Auxin-driven patterning with unidirectional fluxes (United States)

    Cieslak, Mikolaj; Runions, Adam; Prusinkiewicz, Przemyslaw


    The plant hormone auxin plays an essential role in the patterning of plant structures. Biological hypotheses supported by computational models suggest that auxin may fulfil this role by regulating its own transport, but the plausibility of previously proposed models has been questioned. We applied the notion of unidirectional fluxes and the formalism of Petri nets to show that the key modes of auxin-driven patterning—the formation of convergence points and the formation of canals—can be implemented by biochemically plausible networks, with the fluxes measured by dedicated tally molecules or by efflux and influx carriers themselves. Common elements of these networks include a positive feedback of auxin efflux on the allocation of membrane-bound auxin efflux carriers (PIN proteins), and a modulation of this allocation by auxin in the extracellular space. Auxin concentration in the extracellular space is the only information exchanged by the cells. Canalization patterns are produced when auxin efflux and influx act antagonistically: an increase in auxin influx or concentration in the extracellular space decreases the abundance of efflux carriers in the adjacent segment of the membrane. In contrast, convergence points emerge in networks in which auxin efflux and influx act synergistically. A change in a single reaction rate may result in a dynamic switch between these modes, suggesting plausible molecular implementations of coordinated patterning of organ initials and vascular strands predicted by the dual polarization theory. PMID:26116915

  16. Pool size measurements facilitate the determination of fluxes at branching points in nonstationary metabolic flux analysis: The case of Arabidopsis thaliana

    Directory of Open Access Journals (Sweden)

    Robert eHeise


    Full Text Available Pool size measurements are important for the estimation of absolute intracellular fluxes in particular scenarios based on data from heavy carbon isotope experiments. Recently, steady-state fluxes estimates were obtained for central carbon metabolism in an intact illuminated rosette of Arabidopsis thaliana grown photoautotrophically (Szecowka et al., 2013; Heise et al., 2014. Fluxes were estimated therein by integrating mass-spectrometric data of the dynamics of the unlabeled metabolic fraction, data on metabolic pool sizes, partitioning of metabolic pools between cellular compartments and estimates of photosynthetically inactive pools, with a simplified model of plant central carbon metabolism. However, the fluxes were determined by treating the pool sizes as fixed parameters. Here we investigated whether and, if so, to what extent the treatment of pool sizes as parameters to be optimized in three scenarios may affect the flux estimates. The results are discussed in terms of benchmark values for canonical pathways and reactions, including starch and sucrose synthesis as well as the ribulose-1,5-bisphosphate carboxylation and oxygenation reactions. In addition, we discuss pathways emerging from a divergent branch point for which pool sizes are required for flux estimation, irrespective of the computational approach used for the simulation of the observable labelling pattern. Therefore, our findings indicate the necessity for development of techniques for accurate pool size measurements to improve the quality of flux estimates from nonstationary flux estimates in intact plant cells in the absence of alternative flux measurements.

  17. Serpentinization and carbonation of pristine continental ultramafic rocks and applications to the oceanic crust; H2O-CO2 alteration of dunites and re-distribution of Ni-Cu-PGE in sulphide deposits (United States)

    Grant, Thomas; McEnroe, Suzanne; Eske Sørensen, Bjørn; Larsen, Rune; Pastore, Zeudia; Rune Grannes, Kim; Nikolaisen, Even


    Here, we document carbonation and serpentinization within a suite of ultramafic rocks from a continental setting. These ultramafic rocks vary from pristine dunites to varying degrees of serpentinization which locally penetrates the ultramafic complex. Hence, it allows us to observe a number of delicate serpentinization and carbonation reactions, otherwise lost during more extensive alteration or tectonic events. We use a multi-disciplinary approach using petrographic, EPMA, thermodynamic modelling and geophysical data to reveal how the initial stages of serpentization and carbonation in dunites affects the distribution of economic to sub-economic deposits of Ni-Cu and PGE. The data can then be applied to oceanic crust. The samples are dunites and poikilitic wehrlites from the Reinfjord Ultramafic complex, Seiland Igneous Province Northern Norway. The complex formed through crystallization of picritic melts in the lower continental crust. The dunites contain small amounts of interstitial clinopyroxene, sulphides and spinel, with local enrichments in Ni, Cu and PGE. Late magmatic CO2-H2O-S fluids reacted with the dunite forming clots of amphibole + dolomite + sulphides + enstatite, reaction rims of enstatite + dolomite, and inclusions trails of dolomite + enstatite + magnetite + CO2 fluid. Thermodynamic modelling reveals that these textures formed at pressures of >12 kbar and temperatures 850-950 °C, which would be consistent with the late magmatic history of the Reinfjord complex. The clots and reactions have local association with enrichments in gold-rich PGMs. A second stage of alteration involved H2O-dominated fluids. These formed predominantly lizardite serpentinization, as is often concentrated within highly localized fracture zones. Thermodynamic modelling shows that these formed carbonate bearing assemblages leading to the formation of serpentinite, native copper and symplectites of brucite + calcite. The two processes of carbonation and serpentinization re

  18. Two fluxes multistage induction coilgun (United States)

    Gherman, L.; Pearsica, M.; Circiu, I.; Rotaru, C.


    This paper presents a brand new induction electromagnetic launcher, which uses two magnetic fluxes in order to accelerate a projectile. One magnetic flux induce a current in the armature and the second magnetic flux is creating a radial magnetic field. This aproach offer multiple advantages over single flux designs. First we are able to control the induced current in armature because we use the coil just to induce current inside the ring with a great efficiency. Second advantage is the angle of 900 between magnetic field density B and the ring. We used the induction to avoid contact between armature and accelerator. In order to create the magnetic field radial we used four coils perpendicular on armature. This approach alove us to control the phase difference between induced current in armature and current in magnetic field coils for a maximum force. The phase difference is obtained by changing the frequency of magnetic field coils power source. We used simulation software to analyze, and simulate a multistage induction coilgun design with two fluxes. The simulation results demonstrated the theoretical results.

  19. Physics of magnetic flux tubes

    CERN Document Server

    Ryutova, Margarita


    This book is the first account of the physics of magnetic flux tubes from their fundamental properties to collective phenomena in an ensembles of flux tubes. The physics of magnetic flux tubes is absolutely vital for understanding fundamental physical processes in the solar atmosphere shaped and governed by magnetic fields. High-resolution and high cadence observations from recent space and  ground-based instruments taken simultaneously at different heights and temperatures not only show the ubiquity of filamentary structure formation but also allow to study how various events are interconnected by system of magnetic flux tubes. The book covers both theory and observations. Theoretical models presented in analytical and phenomenological forms are tailored for practical applications. These are welded with state-of-the-art observations from early decisive ones to the most recent data that open a new phase-space for exploring the Sun and sun-like stars. Concept of magnetic flux tubes is central to various magn...

  20. Emergency preparedness

    CERN Document Server

    Cennini, E; Oortman Gerlings, P


    On September 19th 2008, a technical fault was at the centre of a sequence of events which hampered the performance of certain equipments of the LHC 3-4 sector. Once the first effects of this sequence of events were detected, the behaviour of the CERN staff confronted to this complex and critical situation became the centre of the risk control process. During such a downward spiral the preparation of all stakeholders is essential and should respect the (apparently) basic principles of emergency preparedness. Preparedness towards normal operation of CERN facilities towards minor up to major emergency situations will be presented. The main technical, organisational and legal frameworks of the CERN emergency preparedness will be recalled, highlighting the CERN risk management and risk control strategy. Then, the sequence of events experienced by different stakeholders on September 19th will be reported, thus starting the learned lessons process.


    Directory of Open Access Journals (Sweden)

    Dragana Pantić


    Full Text Available Emergency contraception refers to any device or drug that is used as an emergency procedure to prevent pregnancy after unprotected sexual intercourse.The first method of emergency contraception was high dose of estrogen. Concern about side effects led to subsequent development of the so-called Yuzpe regimen which combined ethinil estradiol with levonorgestrel and levonorgestrel alone. Less convenient to use is the copper intauterine contraceptive device.It is known that in some women sexual steroids may inhibit or delay ovulation and may interfere with ovum and sperm transport and implantation. Copper intrauterine device causes a foreign-body effect on the endometrium and a direct toxic effect to sperm and blastocyst.The Yuzpe regimen reduces the risk of pregnancy after a single act of sexual intercourse by about 75% and the levonorgestrel alone by about 85%. The copper intrauterine device is an extremely effective method for selected patients.Nausea and vomiting are common among women using the Yuzpe regimen and considerably less common among women using levonorgestrel alone regimen.Emergency contraception is relatively safe with no contraindications except pregnancy. It is ineffective if a woman is pregnant. There is no need for a medical hystory or a phisical examination before providing emergency contraceptive pills. They are taken long before organogenesis starts, so they should not have a teratogenic effect.Counseling should include information about correct use of the method, possible side effects and her preferences for regular contraception.Unintended pregnancy is a great problem. Several safe, effective and inexpensive methods of emergency contraception are available including Yuzpe regimen, levonorges-trel-only regimen and copper intrauterine device.

  2. Reconnecting flux-rope dynamo. (United States)

    Baggaley, Andrew W; Barenghi, Carlo F; Shukurov, Anvar; Subramanian, Kandaswamy


    We develop a model of the fluctuation dynamo in which the magnetic field is confined to thin flux ropes advected by a multiscale model of turbulence. Magnetic dissipation occurs only via reconnection of the flux ropes. This model can be viewed as an implementation of the asymptotic limit R_{m}-->infinity for a continuous magnetic field, where magnetic dissipation is strongly localized to small regions of strong-field gradients. We investigate the kinetic-energy release into heat mediated by the dynamo action, both in our model and by solving the induction equation with the same flow. We find that a flux-rope dynamo is an order of magnitude more efficient at converting mechanical energy into heat. The probability density of the magnetic energy release in reconnections has a power-law form with the slope -3 , consistent with the solar corona heating by nanoflares.

  3. Anthropogenic heat flux estimation from space: first results (United States)

    Chrysoulakis, Nektarios; Heldens, Wieke; Gastellu-Etchegorry, Jean-Philippe; Grimmond, Sue; Feigenwinter, Christian; Lindberg, Fredrik; Del Frate, Fabio; Klostermann, Judith; Mitraka, Zina; Esch, Thomas; Albitar, Ahmad; Gabey, Andrew; Parlow, Eberhard; Olofson, Frans


    While Earth Observation (EO) has made significant advances in the study of urban areas, there are several unanswered science and policy questions to which it could contribute. To this aim the recently launched Horizon 2020 project URBANFLUXES (URBan ANthrpogenic heat FLUX from Earth observation Satellites) investigates the potential of EO to retrieve anthropogenic heat flux, as a key component in the urban energy budget. The anthropogenic heat flux is the heat flux resulting from vehicular emissions, space heating and cooling of buildings, industrial processing and the metabolic heat release by people. Optical, thermal and SAR data from existing satellite sensors are used to improve the accuracy of the radiation balance spatial distribution calculation, using also in-situ reflectance measurements of urban materials are for calibration. EO-based methods are developed for estimating turbulent sensible and latent heat fluxes, as well as urban heat storage flux and anthropogenic heat flux spatial patterns at city scale and local scale by employing an energy budget closure approach. Independent methods and models are engaged to evaluate the derived products and statistical analyses provide uncertainty measures as well. Ultimate goal of the URBANFLUXES is to develop a highly automated method for estimating urban energy budget components to use with Copernicus Sentinel data, enabling its integration into applications and operational services. Thus, URBANFLUXES prepares the ground for further innovative exploitation of European space data in scientific activities (i.e. Earth system modelling and climate change studies in cities) and future and emerging applications (i.e. sustainable urban planning) by exploiting the improved data quality, coverage and revisit times of the Copernicus data. The URBANFLUXES products will therefore have the potential to support both sustainable planning strategies to improve the quality of life in cities, as well as Earth system models to

  4. Where is the Open Flux? (United States)

    Linker, Jon A.; Downs, Cooper; Caplan, Ronald M.; Lionello, Roberto; Mikic, Zoran; Riley, Pete; Henney, Carl John; Arge, Charles; Owens, Matthew


    The Sun’s magnetic field has been observed in the photosphere from ground- and space-based observatories for many years. Global maps of the solar magnetic field based on full disk magnetograms (either built up over a solar rotation, or evolved using flux transport models) are commonly used as boundary conditions for coronal and solar wind models. Maps from different observatories typically agree qualitatively but often disagree quantitatively. Estimation of the coronal/solar wind physics can range from potential field source surface (PFSS) models with empirical prescriptions to magnetohydrodynamic (MHD) models with realistic energy transport and sub-grid scale descriptions of heating and acceleration. Two primary observational constraints on the models are (1) The open field regions in the model should approximately correspond to coronal holes observed in emission, and (2) the magnitude of the open magnetic flux in the model should match that inferred from in situ spacecraft measurements. We have investigated the July 2010 time period, using PFSS and MHD models computed using several available magnetic maps, coronal hole boundaries detected from STEREO and SDO EUV observations, and estimates of the interplanetary magnetic flux from in situ ACE measurements. We show that for all the model/map combinations, models that agree for (1) underestimate the interplanetary magnetic flux, or, conversely, for models to match (2), the modeled open field regions are larger than observed coronal holes. Alternatively, we estimate the open magnetic flux entirely from solar observations by combining detected coronal hole boundaries with observatory synoptic magnetic maps, and show that this method also underestimates the interplanetary magnetic flux. We discuss possible resolutions.Research supported by NASA, AFOSR, and NSF.

  5. Recovery of aquatic insect-mediated methylmercury flux from ponds following drying disturbance. (United States)

    Chumchal, Matthew M; Drenner, Ray W; Greenhill, Frank M; Kennedy, James H; Courville, Ashlyn E; Gober, Charlie A A; Lossau, Luke O


    Small ponds exist across a permanence gradient, and pond permanence is hypothesized to be a primary determinant of insect community structure and insect-mediated methylmercury (MeHg) flux from ponds to the surrounding terrestrial landscape. The present study describes the first experiment examining the recovery of insect-mediated MeHg flux following a drying disturbance that converted permanent ponds with insectivorous fish to semipermanent ponds without fish. Floating emergence traps were used to collect emergent insects for 10 wk in the spring and summer from 5 ponds with fish (permanent) and 5 ponds that were drained to remove fish, dried, and refilled with water (semipermanent). During the 73-d period after semipermanent ponds were refilled, total MeHg flux from semipermanent ponds was not significantly different than total MeHg flux from permanent ponds, indicating that insect-mediated MeHg flux had rapidly recovered in semipermanent ponds following the drying disturbance. Methylmercury fluxes from dragonflies (Odonata: Anisoptera) and phantom midges (Diptera: Chaoboridae) were significantly greater from newly refilled semipermanent ponds than permanent ponds, but the MeHg fluxes from the other 8 emergent insect taxa did not differ between treatments. The present study demonstrates the impact of drying disturbance and the effect of community structure on the cross-system transport of contaminants from aquatic to terrestrial ecosystems. Environ Toxicol Chem 2017;36:1986-1990. © 2017 SETAC. © 2017 SETAC.

  6. Respiratory carbon fluxes in leaves. (United States)

    Tcherkez, Guillaume; Boex-Fontvieille, Edouard; Mahé, Aline; Hodges, Michael


    Leaf respiration is a major metabolic process that drives energy production and growth. Earlier works in this field were focused on the measurement of respiration rates in relation to carbohydrate content, photosynthesis, enzymatic activities or nitrogen content. Recently, several studies have shed light on the mechanisms describing the regulation of respiration in the light and in the dark and on associated metabolic flux patterns. This review will highlight advances made into characterizing respiratory fluxes and provide a discussion of metabolic respiration dynamics in relation to important biological functions. Copyright © 2011 Elsevier Ltd. All rights reserved.

  7. Dermatologic emergencies. (United States)

    Chacon, Anna H


    Although dermatology may be regarded as a medical specialty with few emergencies, they do exist and range from primary cutaneous disorders to severe systemic conditions with skin manifestations. Prompt recognition for appropriate diagnosis and treatment often is necessary to improve a patient's prognosis and a single decision can mark the difference between life and death.

  8. Emerging Materiality

    DEFF Research Database (Denmark)

    Bertelsen, Olav Wedege; Breinbjerg, Morten; Pold, Søren


    The authors examine how materiality emerges from complex chains of mediation in creative software use. The primarily theoretical argument is inspired and illustrated by interviews with two composers of electronic music. The authors argue that computer mediated activity should not primarily...

  9. Emergence delirium

    DEFF Research Database (Denmark)

    Munk, Louise; Andersen, Lars Peter Holst; Gögenur, Ismail


    Emergence delirium (ED) is a well-known phenomenon in the postoperative period. However, the literature concerning this clinical problem is limited. This review evaluates the literature with respect to epidemiology and risk factors. Treatment strategies are discussed. The review concludes...

  10. Neurosurgical emergencies. (United States)

    Kapatkin, A S; Vite, C H


    The neurologic patient is considered a neurosurgical emergency when delay of treatment may influence the patient's outcome. Diseases of the spinal cord, brain, and peripheral nerves are presented in this article. Diagnostic tools (i.e., advanced imaging and electrophysiologic tests), differential diagnoses, treatment options (conventional and controversial), whether the patient requires surgery, and the optimal time for surgical intervention are discussed.

  11. Emerging Options for Emergency Contraception

    Directory of Open Access Journals (Sweden)

    Atsuko Koyama


    Full Text Available Emergency post-coital contraception (EC is an effective method of preventing pregnancy when used appropriately. EC has been available since the 1970s, and its availability and use have become widespread. Options for EC are broad and include the copper intrauterine device (IUD and emergency contraceptive pills such as levonorgestrel, ulipristal acetate, combined oral contraceptive pills (Yuzpe method, and less commonly, mifepristone. Some options are available over-the-counter, while others require provider prescription or placement. There are no absolute contraindications to the use of emergency contraceptive pills, with the exception of ulipristal acetate and mifepristone. This article reviews the mechanisms of action, efficacy, safety, side effects, clinical considerations, and patient preferences with respect to EC usage. The decision of which regimen to use is influenced by local availability, cost, and patient preference.

  12. Emerging Options for Emergency Contraception (United States)

    Koyama, Atsuko; Hagopian, Laura; Linden, Judith


    Emergency post-coital contraception (EC) is an effective method of preventing pregnancy when used appropriately. EC has been available since the 1970s, and its availability and use have become widespread. Options for EC are broad and include the copper intrauterine device (IUD) and emergency contraceptive pills such as levonorgestrel, ulipristal acetate, combined oral contraceptive pills (Yuzpe method), and less commonly, mifepristone. Some options are available over-the-counter, while others require provider prescription or placement. There are no absolute contraindications to the use of emergency contraceptive pills, with the exception of ulipristal acetate and mifepristone. This article reviews the mechanisms of action, efficacy, safety, side effects, clinical considerations, and patient preferences with respect to EC usage. The decision of which regimen to use is influenced by local availability, cost, and patient preference. PMID:24453516

  13. Flux decline in ultrafiltration processes

    NARCIS (Netherlands)

    van den Berg, G.B.; Smolders, C.A.


    When a membrane filtration process such as ultrafiltration is used a flux- and yield-decline can be observed. The causes are i) concentration polarization (i.e. accumulation of retained solutes, reversibly and immediately occurring) and ii) fouling phenomena such as adsorption, pore-blocking and

  14. Black branes in flux compactifications

    Energy Technology Data Exchange (ETDEWEB)

    Torroba, Gonzalo; Wang, Huajia


    We construct charged black branes in type IIA flux compactifications that are dual to (2 + 1)-dimensional field theories at finite density. The internal space is a general Calabi-Yau manifold with fluxes, with internal dimensions much smaller than the AdS radius. Gauge fields descend from the 3-form RR potential evaluated on harmonic forms of the Calabi-Yau, and Kaluza-Klein modes decouple. Black branes are described by a four-dimensional effective field theory that includes only a few light fields and is valid over a parametrically large range of scales. This effective theory determines the low energy dynamics, stability and thermodynamic properties. Tools from flux compactifications are also used to construct holographic CFTs with no relevant scalar operators, that can lead to symmetric phases of condensed matter systems stable to very low temperatures. The general formalism is illustrated with simple examples such as toroidal compactifications and manifolds with a single size modulus. We initiate the classification of holographic phases of matter described by flux compactifications, which include generalized Reissner-Nordstrom branes, nonsupersymmetric AdS2×R2 and hyperscaling violating solutions.

  15. Simple models with ALICE fluxes

    CERN Document Server

    Striet, J


    We introduce two simple models which feature an Alice electrodynamics phase. In a well defined sense the Alice flux solutions we obtain in these models obey first order equations similar to those of the Nielsen-Olesen fluxtube in the abelian higgs model in the Bogomol'nyi limit. Some numerical solutions are presented as well.

  16. Mathematical Modeling of Electrolyte Flow Dynamic Patterns and Volumetric Flow Penetrations in the Flow Channel over Porous Electrode Layered System in Vanadium Flow Battery with Serpentine Flow Field Design


    Ke, Xinyou; Prahl, Joseph M.; Alexander, J. Iwan D.; Savinell, Robert F.


    In this work, a two-dimensional mathematical model is developed to study the flow patterns and volumetric flow penetrations in the flow channel over the porous electrode layered system in vanadium flow battery with serpentine flow field design. The flow distributions at the interface between the flow channel and porous electrode are examined. It is found that the non-linear pressure distributions can distinguish the interface flow distributions under the ideal plug flow and ideal parabolic fl...

  17. X-Ray microtomography analysis of the impact of pCO2 on serpentinization reactions: A reactive percolation experimental approach (United States)

    Escario, Sofia; Godard, Marguerite; Gouze, Philippe; Smal, Pavel; Rodriguez, Olivier; Leprovost, Richard


    Serpentinization is the main hydrothermal process driving the alteration of the mantle lithosphere by seawater at ridges. It consists in the alteration of olivine to serpentine and is associated to processes such as oxidation as well as carbonation when CO2 is present. The sustainability and efficiency of the reaction requires penetration and renewal of fluids at the mineral-fluid interface. Yet the secondary low density minerals can fill the porous network, clogging flow paths efficiently. This study aims at better understanding the coupled hydrodynamic and chemical processes driving the earliest stages of alteration of the ultramafic basement, when seawater-derived hydrothermal fluids penetrate and interact with exposed mantle rocks at slow spreading ridges. We investigate the structural changes of the rock in relation to dissolution-precipitation reactions triggered by the injection CO2-rich seawater using an experimental approach. The experiments simulate open conditions and were performed using the reactive percolation bench ICARE Lab 3 - Géosciences Montpellier. ICARE 3 allows to continuously measuring permeability changes during experiments and sampling the outlet fluids passing through the sample. We analysed the reacted samples before and after the experiments using a combination of geochemical (TGA-MS) and high resolution X-Ray microtomography (ESRF ID19 synchrotron beamline, Grenoble) approaches. A series of experiments was carried out at 190°C and 25 MPa. CO2 enriched natural seawater (XCO2 5.24 mmol/kg) was injected into Titanium capsules (2 mm diameter, 6 mm length) filled by pressed powdered San Carlos olivine (Fo90; grains 150-200 µm). The outlet section of the samples were analysed at 0.65 µm resolution using microtomography before and after the experiments. The reacted powdered sample was analysed by TGA-MS. Comparison of microtomography images of reacted and unreacted samples shows evidences of olivine dissolution and secondary minerals

  18. Oxygen and hydrogen isotope fractionation in serpentine-water and talc-water systems from 250 to 450 °C, 50 MPa (United States)

    Saccocia, Peter J.; Seewald, Jeffrey S.; Shanks, Wayne C.


    Oxygen and hydrogen isotope fractionation factors in the talc–water and serpentine–water systems have been determined by laboratory experiment from 250 to 450 °C at 50 MPa using the partial exchange technique. Talc was synthesized from brucite + quartz, resulting in nearly 100% exchange during reaction at 350 and 450 °C. For serpentine, D–H exchange was much more rapid than 18O–16O exchange when natural chrysotile fibers were employed in the initial charge. In experiments with lizardite as the starting charge, recrystallization to chrysotile enhanced the rate of 18O–16O exchange with the coexisting aqueous phase. Oxygen isotope fractionation factors in both the talc–water and serpentine–water systems decrease with increasing temperature and can be described from 250 to 450 °C by the relationships: 1000 ln  = 11.70 × 106/T2 − 25.49 × 103/T + 12.48 and 1000 ln  = 3.49 × 106/T2 − 9.48 where T is temperature in Kelvin. Over the same temperature interval at 50 MPa, talc–water D–H fractionation is only weakly dependent on temperature, similar to brucite and chlorite, and can be described by the equation: 1000 ln  = 10.88 × 106/T2 − 41.52 × 103/T + 5.61 where T is temperature in Kelvin. Our D–H serpentine–water fractionation factors calibrated by experiment decrease with temperature and form a consistent trend with fractionation factors derived from lower temperature field calibrations. By regression of these data, we have refined and extended the D–H fractionation curve from 25 to 450 °C, 50 MPa as follows: 1000 ln  = 3.436 × 106/T2 − 34.736 × 103/T + 21.67 where T is temperature in Kelvin. These new data should improve the application of D–H and 18O–16O isotopes to constrain the temperature and origin of hydrothermal fluids responsible for serpentine formation in a variety of geologic settings.

  19. Gastrointestinal emergencies. (United States)

    Aronson, L R; Brockman, D J; Brown, D C


    The animal with a surgical gastrointestinal emergency usually requires a rapid, thorough physical examination with concurrent resuscitation. As the diagnosis is being made, the animal must be made as stable as possible before undergoing general anesthesia. During surgery, there must be a critical evaluation of gastrointestinal viability and the use of precise technical skills to achieve the best outcome. Adept postoperative management, including careful monitoring and an index of suspicion for potential complications, is vital.

  20. Emerging Jets

    CERN Document Server

    Schwaller, Pedro; Weiler, Andreas


    In this work, we propose a novel search strategy for new physics at the LHC that utilizes calorimeter jets that (i) are composed dominantly of displaced tracks and (ii) have many different vertices within the jet cone. Such emerging jet signatures are smoking guns for models with a composite dark sector where a parton shower in the dark sector is followed by displaced decays of dark pions back to SM jets. No current LHC searches are sensitive to this type of phenomenology. We perform a detailed simulation for a benchmark signal with two regular and two emerging jets, and present and implement strategies to suppress QCD backgrounds by up to six orders of magnitude. At the 14 TeV LHC, this signature can be probed with mediator masses as large as 1.5 TeV for a range of dark pion lifetimes, and the reach is increased further at the high-luminosity LHC. The emerging jet search is also sensitive to a broad class of long-lived phenomena, and we show this for a supersymmetric model with R-parity violation. Possibilit...

  1. A coupled model of magnetic flux generation and transport in stars (United States)

    Işik, E.; Schmitt, D.; Schüssler, M.


    We present a combined model for magnetic field generation and transport in cool stars with outer convection zones. The mean toroidal magnetic field, which is generated by a cyclic thin-layer \\alpha\\Omega dynamo at the bottom of the convection zone is taken to determine the emergence probability of magnetic flux tubes in the photosphere. Following the nonlinear rise of the unstable thin flux tubes, emergence latitudes and tilt angles of bipolar magnetic regions are determined. These quantities are put into a surface flux transport model, which simulates the surface evolution of magnetic flux under the effects of large-scale flows and turbulent diffusion. First results are discussed for the case of the Sun and for more rapidly rotating solar-type stars. Movies are available via

  2. Connecting extracellular metabolomic measurements to intracellular flux states in yeast

    Directory of Open Access Journals (Sweden)

    Herrgård Markus J


    Full Text Available Abstract Background Metabolomics has emerged as a powerful tool in the quantitative identification of physiological and disease-induced biological states. Extracellular metabolome or metabolic profiling data, in particular, can provide an insightful view of intracellular physiological states in a noninvasive manner. Results We used an updated genome-scale metabolic network model of Saccharomyces cerevisiae, iMM904, to investigate how changes in the extracellular metabolome can be used to study systemic changes in intracellular metabolic states. The iMM904 metabolic network was reconstructed based on an existing genome-scale network, iND750, and includes 904 genes and 1,412 reactions. The network model was first validated by comparing 2,888 in silico single-gene deletion strain growth phenotype predictions to published experimental data. Extracellular metabolome data measured in response to environmental and genetic perturbations of ammonium assimilation pathways was then integrated with the iMM904 network in the form of relative overflow secretion constraints and a flux sampling approach was used to characterize candidate flux distributions allowed by these constraints. Predicted intracellular flux changes were consistent with published measurements on intracellular metabolite levels and fluxes. Patterns of predicted intracellular flux changes could also be used to correctly identify the regions of the metabolic network that were perturbed. Conclusion Our results indicate that integrating quantitative extracellular metabolomic profiles in a constraint-based framework enables inferring changes in intracellular metabolic flux states. Similar methods could potentially be applied towards analyzing biofluid metabolome variations related to human physiological and disease states.

  3. A Simple Analytical Model of Coupled Single Flow Channel over Porous Electrode in Vanadium Redox Flow Battery with Serpentine Flow Channel

    CERN Document Server

    Ke, Xinyou; Prahl, Joseph M; Savinell, Robert F


    A simple analytical model of a layered system comprised of a single passage of a serpentine flow channel and a parallel underlying porous electrode (or porous layer) is proposed. This analytical model is derived from Navier-Stokes motion in the flow channel and Darcy-Brinkman model in the porous layer. The continuities of flow velocity and normal stress are applied at the interface between the flow channel and the porous layer. The effects of the inlet volumetric flow rate, thickness of the flow channel and thickness of a typical carbon fiber paper porous layer on the volumetric flow rate within this porous layer are studied. The maximum current density based on the electrolyte volumetric flow rate is predicted, and found to be consistent with reported numerical simulation. It is found that, for a mean inlet flow velocity of 33.3 cm s-1, the analytical maximum current density is estimated to be 377 mA cm-2, which compares favorably with experimental result reported by others of ~400 mA cm-2.

  4. Ultra-High Resolution Ion Mobility Separations Utilizing Traveling Waves in a 13 m Serpentine Path Length Structures for Lossless Ion Manipulations Module

    Energy Technology Data Exchange (ETDEWEB)

    Deng, Liulin; Ibrahim, Yehia M.; Hamid, Ahmed M.; Garimella, Sandilya V. B.; Webb, Ian K.; Zheng, Xueyun; Prost, Spencer A.; Sandoval, Jeremy A.; Norheim, Randolph V.; Anderson, Gordon A.; Tolmachev, Aleksey V.; Baker, Erin S.; Smith, Richard D.


    We report the development and initial evaluation of a 13-m path length Structures for Lossless Manipulations (SLIM) module for achieving high resolution separations using traveling waves (TW) with ion mobility (IM) spectrometry. The TW SLIM module was fabricated using two mirror-image printed circuit boards with appropriately configured RF, DC and TW electrodes and positioned with a 2.75-mm inter-surface gap. Ions were effective confined between the surfaces by RF-generated pseudopotential fields and moved losslessly through a serpentine path including 44 “U” turns using TWs. The ion mobility resolution was characterized at different pressures, gaps between the SLIM surfaces, TW and RF parameters. After initial optimization the SLIM IM-MS module provided about 5-fold higher resolution separations than present commercially available drift tube or traveling wave IM-MS platforms. Peak capacity and peak generation rates achieved were 246 and 370 s-1, respectively, at a TW speed of 148 m/s. The high resolution achieved in the TW SLIM IM-MS enabled e.g., isomeric sugars (Lacto-N-fucopentaose I and Lacto-N-fucopentaose II) to be baseline resolved, and peptides from a albumin tryptic digest much better resolved than with existing commercial IM-MS platforms. The present work also provides a foundation for the development of much higher resolution SLIM devices based upon both considerably longer path lengths and multi-pass designs.

  5. Ultra-High Resolution Ion Mobility Separations Utilizing Traveling Waves in a 13 m Serpentine Path Length Structures for Lossless Ion Manipulations Module. (United States)

    Deng, Liulin; Ibrahim, Yehia M; Hamid, Ahmed M; Garimella, Sandilya V B; Webb, Ian K; Zheng, Xueyun; Prost, Spencer A; Sandoval, Jeremy A; Norheim, Randolph V; Anderson, Gordon A; Tolmachev, Aleksey V; Baker, Erin S; Smith, Richard D


    We report the development and initial evaluation of a 13 m path length Structures for Lossless Manipulations (SLIM) module for achieving high resolution separations using traveling waves (TW) with ion mobility (IM) spectrometry. The TW SLIM module was fabricated using two mirror-image printed circuit boards with appropriately configured RF, DC, and TW electrodes and positioned with a 2.75 mm intersurface gap. Ions were effectively confined in field-generated conduits between the surfaces by RF-generated pseudopotential fields and moved losslessly through a serpentine path including 44 "U" turns using TWs. The ion mobility resolution was characterized at different pressures, gaps between the SLIM surfaces, and TW and RF parameters. After initial optimization, the SLIM IM-MS module provided about 5-fold higher resolution separations than present commercially available drift tube or traveling wave IM-MS platforms. Peak capacity and peak generation rates achieved were 246 and 370 s(-1), respectively, at a TW speed of 148 m/s. The high resolution achieved in the TW SLIM IM-MS enabled, e.g., isomeric sugars (lacto-N-fucopentaose I and lacto-N-fucopentaose II) to be baseline resolved, and peptides from an albumin tryptic digest were much better resolved than with existing commercial IM-MS platforms. The present work also provides a foundation for the development of much higher resolution SLIM devices based upon both considerably longer path lengths and multipass designs.

  6. Modeling of quantitative effects of water components on the photocatalytic degradation of 17α-ethynylestradiol in a modified flat plate serpentine reactor. (United States)

    Wang, Dawei; Li, Yi; Li, Guoping; Wang, Chao; Zhang, Wenlong; Wang, Qing


    The effect of water components on the photocatalytic degradation of organic pollutants was incompletely understood, especially in the case of hydroxyl radical (•OH) generation and scavenging. Previous studies have used various methods to determine the rate constants for the reactions between •OH and water components, but the interactions between water components were not taken into concern. In this study, a sequential relative rate technique was used to investigate the effects of water components on the rates of •OH generation and EE2 degradation in a modified flat plate serpentine reactor, including NO₃(-), H₂PO₄(-), SO₄(2-), CO₃(2-), Cl(-), Na(+), Fe(3+), dissolved organic matter (DOM) etc. The results reflected that NO₃(-) and DOM accelerated the photodegradation of 17α-ethynylestradiol (EE2) (3.2% and 21.2%, respectively). Cl(-) and Fe(3+) inhibited that process (5.2% and 3.1%, respectively). Finally, a model for the photocatalytic degradation of EE2 was developed for the first time, taking the obtained rate constants, catalyst concentrations, flow velocities and light intensities into concern. A good agreement was observed between the model and experimental profiles. Copyright © 2013 Elsevier B.V. All rights reserved.

  7. Performance analysis of a continuous serpentine flow reactor for electrochemical oxidation of synthetic and real textile wastewater: Energy consumption, mass transfer coefficient and economic analysis. (United States)

    Pillai, Indu M Sasidharan; Gupta, Ashok K


    A continuous flow electrochemical reactor was developed, and its application was tested for the treatment of textile wastewater. A parallel plate configuration with serpentine flow was chosen for the continuous flow reactor. Uniparameter optimization was carried out for electrochemical oxidation of synthetic and real textile wastewater (collected from the inlet of the effluent treatment plant). Chemical Oxygen Demand (COD) removal efficiency of 90% was achieved for synthetic textile wastewater (initial COD - 780 mg L-1) at a flow rate of 500 mL h-1 (retention time of 6 h) and a current density of 1.15 mA cm-2 and the energy consumption for the degradation was 9.2 kWh (kg COD)-1. The complete degradation of real textile wastewater (initial COD of 368 mg L-1) was obtained at a current density of 1.15 mA cm-2, NaCl concentration of 1 g L-1 and retention time of 6 h. Energy consumption and mass transfer coefficient of the reactions were calculated. The continuous flow reactor performed better than batch reactor with reference to energy consumption and economy. The overall treatment cost for complete COD removal of real textile wastewater was 5.83 USD m-3. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Is it an Emergency? (United States)

    ... Emergency 101 Share this! Home » Emergency 101 Is it an Emergency? Medical emergencies can be frightening and ... situation. Here you can find information about emergencies. It is essential to know how to recognize the ...

  9. Flavour mixings in flux compactifications

    Energy Technology Data Exchange (ETDEWEB)

    Buchmuller, Wilfried; Schweizer, Julian


    A multiplicity of quark-lepton families can naturally arise as zero-modes in flux compactifications. The flavour structure of quark and lepton mass matrices is then determined by the wave function profiles of the zero-modes. We consider a supersymmetric SO(10) x U(1) model in six dimensions compactified on the orbifold T{sup 2}=Z{sub 2} with Abelian magnetic flux. A bulk 16-plet charged under the U(1) provides the quark-lepton generations whereas two uncharged 10-plets yield two Higgs doublets. Bulk anomaly cancellation requires the presence of additional 16- and 10-plets. The corresponding zero-modes form vectorlike split multiplets that are needed to obtain a successful flavour phenomenology. We analyze the pattern of flavour mixings for the two heaviest families of the Standard Model and discuss possible generalizations to three and more generations.

  10. Constrained Allocation Flux Balance Analysis

    CERN Document Server

    Mori, Matteo; Martin, Olivier C; De Martino, Andrea; Marinari, Enzo


    New experimental results on bacterial growth inspire a novel top-down approach to study cell metabolism, combining mass balance and proteomic constraints to extend and complement Flux Balance Analysis. We introduce here Constrained Allocation Flux Balance Analysis, CAFBA, in which the biosynthetic costs associated to growth are accounted for in an effective way through a single additional genome-wide constraint. Its roots lie in the experimentally observed pattern of proteome allocation for metabolic functions, allowing to bridge regulation and metabolism in a transparent way under the principle of growth-rate maximization. We provide a simple method to solve CAFBA efficiently and propose an "ensemble averaging" procedure to account for unknown protein costs. Applying this approach to modeling E. coli metabolism, we find that, as the growth rate increases, CAFBA solutions cross over from respiratory, growth-yield maximizing states (preferred at slow growth) to fermentative states with carbon overflow (preferr...

  11. Structural Control of Metabolic Flux (United States)

    Sajitz-Hermstein, Max; Nikoloski, Zoran


    Organisms have to continuously adapt to changing environmental conditions or undergo developmental transitions. To meet the accompanying change in metabolic demands, the molecular mechanisms of adaptation involve concerted interactions which ultimately induce a modification of the metabolic state, which is characterized by reaction fluxes and metabolite concentrations. These state transitions are the effect of simultaneously manipulating fluxes through several reactions. While metabolic control analysis has provided a powerful framework for elucidating the principles governing this orchestrated action to understand metabolic control, its applications are restricted by the limited availability of kinetic information. Here, we introduce structural metabolic control as a framework to examine individual reactions' potential to control metabolic functions, such as biomass production, based on structural modeling. The capability to carry out a metabolic function is determined using flux balance analysis (FBA). We examine structural metabolic control on the example of the central carbon metabolism of Escherichia coli by the recently introduced framework of functional centrality (FC). This framework is based on the Shapley value from cooperative game theory and FBA, and we demonstrate its superior ability to assign “share of control” to individual reactions with respect to metabolic functions and environmental conditions. A comparative analysis of various scenarios illustrates the usefulness of FC and its relations to other structural approaches pertaining to metabolic control. We propose a Monte Carlo algorithm to estimate FCs for large networks, based on the enumeration of elementary flux modes. We further give detailed biological interpretation of FCs for production of lactate and ATP under various respiratory conditions. PMID:24367246

  12. Sediment flux and the Anthropocene. (United States)

    Syvitski, James P M; Kettner, Albert


    Data and computer simulations are reviewed to help better define the timing and magnitude of human influence on sediment flux--the Anthropocene epoch. Impacts on the Earth surface processes are not spatially or temporally homogeneous. Human influences on this sediment flux have a secondary effect on floodplain and delta-plain functions and sediment dispersal into the coastal ocean. Human impact on sediment production began 3000 years ago but accelerated more widely 1000 years ago. By the sixteenth century, societies were already engineering their environment. Early twentieth century mechanization has led to global signals of increased sediment flux in most large rivers. By the 1950s, this sediment disturbance signal reversed for many rivers owing to the proliferation of dams, and sediment load reduction below pristine conditions is the dominant signal today. A delta subsidence signal began in the 1930s and is now a dominant signal in terms of sea level for many coastal environments, overwhelming even the global warming imprint on sea level. Humans have engineered how most water and sediment are discharged into the coastal ocean. Hyperpycnal flow events have become more common for some rivers, and less common for other rivers. Bottom trawling is now widespread, suggesting that even continental shelves have received a significant but as yet quantified Anthropocene impact. The Anthropocene attains the level of a geological climate event, such as that seen in the transition between the Pleistocene and the Holocene.

  13. Surface fluxes in heterogeneous landscape

    Energy Technology Data Exchange (ETDEWEB)

    Bay Hasager, C.


    The surface fluxes in homogeneous landscapes are calculated by similarity scaling principles. The methodology is well establish. In heterogeneous landscapes with spatial changes in the micro scale range, i e from 100 m to 10 km, advective effects are significant. The present work focus on these effects in an agricultural countryside typical for the midlatitudes. Meteorological and satellite data from a highly heterogeneous landscape in the Rhine Valley, Germany was collected in the large-scale field experiment TRACT (Transport of pollutants over complex terrain) in 1992. Classified satellite images, Landsat TM and ERS SAR, are used as basis for roughness maps. The roughnesses were measured at meteorological masts in the various cover classes and assigned pixel by pixel to the images. The roughness maps are aggregated, i e spatially averaged, into so-called effective roughness lengths. This calculation is performed by a micro scale aggregation model. The model solves the linearized atmospheric flow equations by a numerical (Fast Fourier Transform) method. This model also calculate maps of friction velocity and momentum flux pixel wise in heterogeneous landscapes. It is indicated how the aggregation methodology can be used to calculate the heat fluxes based on the relevant satellite data i e temperature and soil moisture information. (au) 10 tabs., 49 ills., 223 refs.

  14. Determination of Energy Fluxes Over Agricultural Surfaces

    Directory of Open Access Journals (Sweden)

    Josefina Argete


    Full Text Available An energy budget was conducted over two kinds if surfaces: grass and corn canopy. The net radiative flux and the soil heat flux were directly measured while the latent and sensible heat flux were calculated from the vertical profiles if wet and dry-bulb temperature and wind speed. The crop storage flux was also estimated. Using the gradient or aerodynamic equations, the calculated fluxes when compared to the measured fluxes in the context of an energy budget gave an SEE = 63 Wm-2 over grass and SEE = 81 Wm-2 over corn canopy. The calculated fluxes compared reasonably well with those obtained using the Penman equations.For an energy budget research with limited instrumentation, the aerodynamic method performed satisfactorily in estimating the daytime fluxes, when atmospheric conditions are fully convective, but failed when conditions were stably stratified as during nighttime.

  15. Flux Enhancement in Membrane Distillation Using Nanofiber Membranes

    Directory of Open Access Journals (Sweden)

    T. Jiříček


    Full Text Available Membrane distillation (MD is an emerging separation technology, whose largest application potential lies in the desalination of highly concentrated solutions, which are out of the scope of reverse osmosis. Despite many attractive features, this technology is still awaiting large industrial application. The main reason is the lack of commercially available membranes with fluxes comparable to reverse osmosis. MD is a thermal separation process driven by a partial vapour pressure difference. Flux, distillate purity, and thermal efficiency are always in conflict, all three being strictly connected with pore size, membrane hydrophobicity, and thickness. The world has not seen the ideal membrane yet, but nanofibers may offer a solution to these contradictory requirements. Membranes of electrospun PVDF were tested under various conditions on a direct contact (DCMD unit, in order to determine the optimum conditions for maximum flux. In addition, their performance was compared to commonly available PTFE, PE, and PES membranes. It was confirmed that thinner membranes have higher fluxes and a lower distillate purity and also higher energy losses via conduction across the membrane. As both mass and heat transfer are connected, it is best to develop new membranes with a target application in mind, for the specific membrane module and operational conditions.

  16. High-flux solar photon processes

    Energy Technology Data Exchange (ETDEWEB)

    Lorents, D C; Narang, S; Huestis, D C; Mooney, J L; Mill, T; Song, H K; Ventura, S [SRI International, Menlo Park, CA (United States)


    This study was commissioned by the National Renewable Energy Laboratory (NREL) for the purpose of identifying high-flux photoprocesses that would lead to beneficial national and commercial applications. The specific focus on high-flux photoprocesses is based on the recent development by NREL of solar concentrator technology capable of delivering record flux levels. We examined photolytic and photocatalytic chemical processes as well as photothermal processes in the search for processes where concentrated solar flux would offer a unique advantage. 37 refs.

  17. Force sensor using changes in magnetic flux (United States)

    Pickens, Herman L. (Inventor); Richard, James A. (Inventor)


    A force sensor includes a magnetostrictive material and a magnetic field generator positioned in proximity thereto. A magnetic field is induced in and surrounding the magnetostrictive material such that lines of magnetic flux pass through the magnetostrictive material. A sensor positioned in the vicinity of the magnetostrictive material measures changes in one of flux angle and flux density when the magnetostrictive material experiences an applied force that is aligned with the lines of magnetic flux.

  18. Calibration of soil heat flux sensors.

    NARCIS (Netherlands)

    Loon, van W.K.P.; Bastings, H.M.H.; Moors, E.J.


    Soil heat flux is difficult to measure accurately and soil heat flux plates are difficult to calibrate. In this research the reference heat flux was calculated from the temperature gradient and independent thermal conductivity measurements. Reference conductivities, as measured by the non-steady

  19. Surface fluxes over natural landscapes using scintillometry

    NARCIS (Netherlands)

    Meijninger, W.M.L.


    Motivated by the demand for reliable area-averaged fluxes associated with natural landscapes this thesis investigates a relative new measurement technique known as the scintillation method. For homogeneous areas the surface fluxes can be derived with reasonable accuracy. However, fluxes

  20. Metabolic Flux Analysis of Mammalian Cells

    NARCIS (Netherlands)

    Martens, D.E.


    Metabolic flux analysis has become a standard tool for analyzing metabolism and optimizing bioprocesses. Metabolic flux analysis makes use of a metabolic reaction network in combination with extra-cellular measurements and mass balancing to calculate flux distributions in metabolism. It is a useful

  1. Apparatus for measuring a flux of neutrons (United States)

    Stringer, James L.


    A flux of neutrons is measured by disposing a detector in the flux and applying electronic correlation techniques to discriminate between the electrical signals generated by the neutron detector and the unwanted interfering electrical signals generated by the incidence of a neutron flux upon the cables connecting the detector to the electronic measuring equipment at a remote location.

  2. Emerging Multinationals

    DEFF Research Database (Denmark)

    Gammeltoft, Peter

    abroad. Even though FDI usually constitutes only a minor part of countries' total capital formation, the relationships between FDI and economic growth, welfare, and industrial upgrading in developing countries have been the object of long and extensive treatment in the literature. However, the literature...... countries. Apart from a few early pioneering studies (Lecraw 1977; Lall 1983; Wells 1983; Agarwal 1985) only few studies have been made so far of outward investment from emerging and developing economies. This is in spite of the fact that the value of outward FDI stock from developing countries reached USD......859 billion in 2003, up from USD129 billion in 1990, and has increased 11 times since 1985. A limited number of recent studies do exist, though (e.g. Cai 1999; Lecraw 1993; van Hoesel 1999; Tolentino 1993; Andreff 2003; Chudnovsky and López 2000; Bulatov 1998, Yeung 2000). Furthermore, academic...

  3. Emergencies and Emergency Permits for Ocean Dumping (United States)

    Emergency permits under the MPRSA are issued if disposed material poses a threat to human health. Information is provided on emergency permit examples and disposal sites. Emergencies to safeguard life at sea does not require an ocean dumping permit.

  4. Geometrical correction factors for heat flux meters (United States)

    Baumeister, K. J.; Papell, S. S.


    General formulas are derived for determining gage averaging errors of strip-type heat flux meters used in the measurement of one-dimensional heat flux distributions. The local averaging error e(x) is defined as the difference between the measured value of the heat flux and the local value which occurs at the center of the gage. In terms of e(x), a correction procedure is presented which allows a better estimate for the true value of the local heat flux. For many practical problems, it is possible to use relatively large gages to obtain acceptable heat flux measurements.

  5. Emergency contraception. (United States)

    Gemzell-Danielsson, Kristina; Rabe, Thomas; Cheng, Linan


    There have been numerous attempts to control fertility after unprotected sexual intercourse (UPSI). From very bizarre methods like the vaginal application of Coca Cola to the more serious attempts using calcium antagonists influencing fertility parameters in sperm to hormonal methods or intrauterine devices. So far, hormonal methods preventing or delaying ovulation have proved to be the most popular starting with the combination of ethinyl estradiol and levonorgestrel (LNG), known as the Yuzpe regimen. The first dose had to be taken within 72 hours of UPSI, a second one 12 hours later. Later on, LNG alone, at first in a regimen similar to the Yuzpe method (2 × 0.75 mg 12 hours apart) showed to be more successful, eventually resulting in the development of a 1.5 mg LNG pill that combined good efficacy with a high ease of use. Several efficacious and easy to use methods for emergency contraception (EC) are available on the market today with the most widely spread being LNG in a single dose of 1.5 mg (given as one tablet of 1.5 mg or 2 tablets of 0.75 mg each) for administration up to 3 days (according to WHO up to 5 days) after UPSI. Its limitations are the non-optimal efficacy which is decreasing the later the drug is taken and the fact that it is only approved for up to 72 hours after UPSI. This regimen has no effect on the endometrium, corpus luteum function and implantation, is not abortive and don't harm the fetus if accidentally taken in early pregnancy. It has no impact on the rate of ectopic pregnancies. It has become the standard method used up to this day in most countries. Since the mid 1970s copper IUDs have been used for EC, which show a high efficacy. Their disadvantages lie in the fact that EC is considered an off label use for most IUDs (not for the GynFix copper IUD in the European Union) and that they might not be acceptable for every patient. Furthermore IUD-insertion is an invasive procedure and it is required trained providers and

  6. Flux limiters and Eddington factors

    Energy Technology Data Exchange (ETDEWEB)

    Pomraning, G.C.


    In this paper a closure scheme for the first two angular moments of the time-dependent equation of transfer is presented, either via an Eddington factor which leads to a telegrapher's description, or via a Fick's law which leads to a diffusion description. Points discussed include boundary conditions (both an extension of the classic Marshak-Milne condition and those arising from a boundary layer analysis), the flux limiting feature of the diffusion approximation, and the reduction of the theory to asymptotic diffusion theory in the steady state limit.

  7. Methane Fluxes from Subtropical Wetlands (United States)

    DeLucia, N.; Gomez-Casanovas, N.; Bernacchi, C.


    It is well documented that green house gas concentrations have risen at unequivocal rates since the industrial revolution but the disparity between anthropogenic sources and natural sources is uncertain. Wetlands are one example of a natural ecosystem that can be a substantial source or sink for methane (CH4) depending on climate conditions. Due to strict anaerobic conditions required for CH4-generating microorganisms, natural wetlands are one of the main sources for biogenic CH4. Although wetlands occupy less than 5% of total land surface area, they contribute approximately 20% of total CH4 emissions to the atmosphere. The processes regulating CH4 emissions are sensitive to land use and management practices of areas surrounding wetlands. Variation in adjacent vegetation or grazing intensity by livestock can, for example, alter CH4 fluxes from wetland soils by altering nutrient balance, carbon inputs and hydrology. Therefore, understanding how these changes will affect wetland source strength is essential to understand the impact of wetland management practices on the global climate system. In this study we quantify wetland methane fluxes from subtropical wetlands on a working cattle ranch in central Florida near Okeechobee Lake (27o10'52.04'N, 81o21'8.56'W). To determine differences in CH4 fluxes associated with land use and management, a replicated (n = 4) full factorial experiment was designed for wetlands where the surrounding vegetation was (1) grazed or un-grazed and (2) composed of native vegetation or improved pasture. Net exchange of CH4 and CO2 between the land surface and the atmosphere were sampled with a LICOR Li-7700 open path CH4 analyzer and Li-7500A open path CO2/H20 analyzer mounted in a 1-m3 static gas-exchange chamber. Our results showed and verified that CH4 emissions from subtropical wetlands were larger when high soil moisture was coupled with high temperatures. The presence of cattle only amplified these results. These results help quantify

  8. Emerging technologies

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Shin-yee


    The mission of the Emerging Technologies thrust area at Lawrence Livermore National Laboratory is to help individuals establish technology areas that have national and commercial impact, and are outside the scope of the existing thrust areas. We continue to encourage innovative ideas that bring quality results to existing programs. We also take as our mission the encouragement of investment in new technology areas that are important to the economic competitiveness of this nation. In fiscal year 1992, we have focused on nine projects, summarized in this report: (1) Tire, Accident, Handling, and Roadway Safety; (2) EXTRANSYT: An Expert System for Advanced Traffic Management; (3) Odin: A High-Power, Underwater, Acoustic Transmitter for Surveillance Applications; (4) Passive Seismic Reservoir Monitoring: Signal Processing Innovations; (5) Paste Extrudable Explosive Aft Charge for Multi-Stage Munitions; (6) A Continuum Model for Reinforced Concrete at High Pressures and Strain Rates: Interim Report; (7) Benchmarking of the Criticality Evaluation Code COG; (8) Fast Algorithm for Large-Scale Consensus DNA Sequence Assembly; and (9) Using Electrical Heating to Enhance the Extraction of Volatile Organic Compounds from Soil.

  9. Emerging memories (United States)

    Baldi, Livio; Bez, Roberto; Sandhu, Gurtej


    Memory is a key component of any data processing system. Following the classical Turing machine approach, memories hold both the data to be processed and the rules for processing them. In the history of microelectronics, the distinction has been rather between working memory, which is exemplified by DRAM, and storage memory, exemplified by NAND. These two types of memory devices now represent 90% of all memory market and 25% of the total semiconductor market, and have been the technology drivers in the last decades. Even if radically different in characteristics, they are however based on the same storage mechanism: charge storage, and this mechanism seems to be near to reaching its physical limits. The search for new alternative memory approaches, based on more scalable mechanisms, has therefore gained new momentum. The status of incumbent memory technologies and their scaling limitations will be discussed. Emerging memory technologies will be analyzed, starting from the ones that are already present for niche applications, and which are getting new attention, thanks to recent technology breakthroughs. Maturity level, physical limitations and potential for scaling will be compared to existing memories. At the end the possible future composition of memory systems will be discussed.

  10. Growth and Metal Accumulation of an Alyssum murale Nickel Hyperaccumulator Ecotype Co-cropped with Alyssum montanum and Perennial Ryegrass in Serpentine Soil

    Directory of Open Access Journals (Sweden)

    Catherine Leigh Broadhurst


    Full Text Available The genus Alyssum (Brassicaceae contains Ni hyperaccumulators (50, many of which can achieve 30 g kg-1 Ni in dry leaf. Some Alyssum hyperaccumulators are viable candidates for commercial Ni phytoremediation and phytomining technologies. It is not known whether these species secrete organic and/or amino acids into the rhizosphere to solubilize Ni, or can make use of such acids within the soil to facilitate uptake. It has been hypothesized that in fields with mixed plant species, mobilization of metals by phytosiderophores secreted by Graminaceae plants could affect Alyssum Ni, Fe, Cu and Mn uptake.We co-cropped the Ni hyperaccumulator Alyssum murale, non-hyperaccumulator A. montanum and perennial ryegrass in a natural serpentine soil. All treatments had standard inorganic fertilization required for ryegrass growth and one treatment was compost amended. After 4 months A. murale leaves and stems contained 3600 mg kg-1 Ni which did not differ significantly with co-cropping. Overall Ni and Mn concentrations were significantly higher in A. murale than in A. montanum or L. perenne. Copper was not accumulated by either Alyssum species, but L. perenne accumulated up to 10 mg kg-1. A. montanum could not compete with either A. murale or ryegrass, and neither Alyssum species survived in the compost-amended soil. Co-cropping with ryegrass reduced Fe and Mn concentrations in A. murale but not to the extent of either increasing Ni uptake or affecting plant nutrition. The hypothesized Alyssum Ni accumulation in response to phytosiderophores secreted by co-cropped grass did not occur. Our data do not support increased mobilization of Mn by a phytosiderophore mechanism either, but the converse: mobilization of Mn by the Alyssum hyperaccumulator species significantly increased Mn levels in L. perenne. Tilling soil to maximize root penetration, adequate inorganic fertilization and appropriate plant densities are more important for developing efficient

  11. Flux of Millimetric Space Debris (United States)

    Goldstein, R. M.; Goldstein, S. J., Jr.


    In 21.4 hr of zenith radar observations on 4 days at 8510 MHz, we found 831 particles with altitudes between 177 and 1662 km. From the duration of the echoes and the angular size (0.030 deg) of the antenna beam 157 particles were identified as passing through the side lobes and not through the main beam. Our analysis is based on the 674 particles that did not broaden the beam. On the assumptions that these particles went through the main beam, their radar cross sections vary between 0.02 and 260 sq mm , and their radial velocities vary between +/- 700 m/s. If they are conducting spheres, their diameters lie between 2 and 18 mm. If not, they must be larger. The flux of these particles, that is the number per sq km day, was determined in 100 km intervals. The maximum flux, 3.3 particles per sq km day, occurs at 950 km altitude. The small and large particles are not well mixed. The largest particles occur beyond 1000 km and middle-sized particles are missing below 300 km. If the earth's atmosphere caused the smallest particles to lose energy from initial orbits identical to those of the large particles, the orbits would have lower eccentricity at low altitudes. We find a larger eccentricity for the inner particles, and conclude that two or more populations are present.

  12. DWSB in heterotic flux compactifications

    CERN Document Server

    Held, Johannes; Marchesano, Fernando; Martucci, Luca


    We address the construction of non-supersymmetric vacua in heterotic compactifications with intrinsic torsion and background fluxes. In particular, we implement the approach of domain-wall supersymmetry breaking (DWSB) previously developed in the context of type II flux compactifications. This approach is based on considering backgrounds where probe NS5-branes wrapping internal three-cycles and showing up as four-dimensional domain-walls do not develop a BPS bound, while all the other BPS bounds characterizing the N=1 supersymmetric compactifications are preserved at tree-level. Via a scalar potential analysis we provide the conditions for these backgrounds to solve the ten-dimensional equations of motion including order \\alpha' corrections. We also consider backgrounds where some of the NS5-domain-walls develop a BPS bound, show their relation to no-scale SUSY-breaking vacua and construct explicit examples via elliptic fibrations. Finally, we consider backgrounds with a non-trivial gaugino condensate and dis...

  13. How the Saturnian Magnetosphere Conserves Magnetic Flux (United States)

    Powell, R. L.; Wei, H.; Russell, C. T.; Arridge, C. S.; Dougherty, M. K.


    The magnetospheric dynamics at Saturn are driven by the centrifugal force of near co-rotating water group ions released at a rate of hundreds of kilograms per second by Saturn's moon Enceladus. The plasma is accelerated up to co-rotation speed by the magnetospheric magnetic field coupled to the Saturnian ionosphere. The plasma is lost ultimately through the process of magnetic reconnection in the tail. Conservation of magnetic flux requires that plasma-depleted, "empty" flux tubes return magnetic flux to the inner magnetosphere. After completion of the initial inrush of the reconnected and largely emptied flux tubes inward of the reconnection point, the flux tubes face the outflowing plasma and must move inward against the flow. Observations of such flux tubes have been identified in the eight years of Cassini magnetometer data. The occurrence of these tubes is observed at all local times indicating slow inward transport of the tubes relative to the co-rotation speed. Depleted flux tubes observed in the equatorial region appear as an enhancement in the magnitude of the magnetic field, whereas the same flux tubes observed at higher latitudes appear as decreased field strength. The difference in appearance of the low latitude and the high latitude tubes is due to the plasma environment just outside the tube. Warm low-density plasma fills the inside of the flux tube at all latitudes. This flux tube thus will expand in the less dense regions away from the magnetic equator and will be observed as a decrease in the magnitude of the magnetic field from the background. These flux tubes near the equator, where the plasma density outside of the flux tube is much greater, will be observed as an enhancement in the magnitude of the magnetic field. Cassini magnetometer and CAPS data are examined to understand the properties of these flux tubes and their radial and latitudinal evolution throughout the Saturnian magnetospheric environment.

  14. Partitioning evapotranspiration fluxes using atmometer (United States)

    Orsag, Matej; Fischer, Milan; Trnka, Miroslav; Kucera, Jiri; Zalud, Zdenek


    This effort is aimed to derive a simple tool for separating soil evaporation and transpiration from evapotranspiration, measured by Bowen ration energy balance method (BREB) in short rotation coppice (SRC). The main idea is to utilize daily data of actual evapotranspiration (ETa) measured above bare soil (spring 2010 - first year following harvest), reference evapotranspiration (ETo) measured by atmometer ETgage and precipitation data, in order to create an algorithm for estimation evaporation from bare soil. This approach is based on the following assumption: evaporation of wetted bare soil same as the ETo from atmometer is assumed to be identical in days with rain. In first and further days with no rain (and e.g. high evaporative demand) the easily evaporable soil water depletes and ETa so as crop coefficient of bare soil (Kcb) decreases in a way similar to decreasing power function. The algorithm represents a parameterized function of daily cumulated ETo (ETc) measured by atmometer in days elapsed from last rain event (Kcb = a*ETc^b). After each rain event the accumulation of ETo starts again till next rain event (e. g. only days with no rain are cumulated). The function provides decreasing Kcb for each day without rain. The bare soil evaporation can be estimated when the atmometer-recorded value is multiplied by Kcb for particular day without rain. In days with rain Kcb is assumed to be back at 1. This method was successfully tested for estimating evaporation from bare soil under closed canopy of poplar-based SRC. When subtracting the estimated soil evaporation from total ETa flux, measured above the canopy using BREB method, it is possible to obtain transpiration flux of the canopy. There is also possibility to test this approach on the contrary - subtracting transpiration derived from sap-flow measurement from total ETa flux is possible to get soil evaporation as well. Acknowledgements: The present experiment is made within the frame of project Inter

  15. Chaos in Magnetic Flux Ropes (United States)

    Gekelman, Walter; DeHaas, T.; Van Compernolle, B.; Vincena, S.


    Magnetic Flux Ropes Immersed in a uniform magnetoplasma are observed to twist about themselves, writhe about each other and rotate about a central axis. They are kink unstable and smash into one another as they move. Each collision results in magnetic field line generation and the generation of a quasi-seperatrix layer. Three dimensional magnetic field lines are computed by conditionally averaging the data using correlation techniques. When the currents associated with the ropes are large,this is possible for only a number of rotation cycles as the field line motion becomes chaotic. The permutation entropy1 can be calculated from the the time series of the magnetic field data (this is also done with flows) and used to calculate the positions of the data on a Jensen Shannon complexity map2. The power spectra of much of the magnetic and flow data is exponential and Lorentzian structures in the time domain are embedded in them. The location of data on this map indicates if the magnetic fields are stochastic, or fall into regions of minimal or maximal complexity. The complexity is a function of space and time. The complexity map, and analysis will be explained in the course of the talk. Other types of chaotic dynamical models such as the Lorentz or Gissinger process also fall on the map and can give a clue to the nature of the flux rope turbulence. The ropes fall in the region of the C-H plane where chaotic systems lie. 1 C. Bandt, B. Pompe, Phys. Rev. Lett., 88,174102 (2007) 2 O. Russo et al., Phys. Rev. Lett., 99, 154102 (2007), J. Maggs, G.Morales, “Permutation Entropy analysis of temperature fluctuations from a basic electron heat transport experiment”,submitted PPCF (2013)

  16. Magnetic Energy and Helicity in Two Emerging Active Regions in the Sun (United States)

    Liu, Y.; Schuck, P. W.


    The magnetic energy and relative magnetic helicity in two emerging solar active regions, AR 11072 and AR 11158,are studied. They are computed by integrating over time the energy and relative helicity fluxes across the photosphere. The fluxes consist of two components: one from photospheric tangential flows that shear and braid field lines (shear term), the other from normal flows that advect magnetic flux into the corona (emergence term). For these active regions: (1) relative magnetic helicity in the active-region corona is mainly contributed by the shear term,(2) helicity fluxes from the emergence and the shear terms have the same sign, (3) magnetic energy in the corona (including both potential energy and free energy) is mainly contributed by the emergence term, and(4) energy fluxes from the emergence term and the shear term evolved consistently in phase during the entire flux emergence course.We also examine the apparent tangential velocity derived by tracking field-line footpoints using a simple tracking method. It is found that this velocity is more consistent with tangential plasma velocity than with the flux transport velocity, which agrees with the conclusion by Schuck.

  17. Structure and correlations of the flux line lattice in crystalline Nb through the peak effect

    DEFF Research Database (Denmark)

    Gammel, P.L.; Yaron, U.; Ramirez, Y.P.


    We have measured the structure of the field cooled flux line lattice (FLL) in single crystal Nb using small angle neutron scattering. Augmented by transport and thermodynamic data, a scenario for the dramatic disordering of the FLL near the peak effect emerges. A precursor to the peak effect...

  18. Emergency teams in Danish emergency departments

    DEFF Research Database (Denmark)

    Lafrenz, Thomas; Lindberg, Søren Østergaard; La Cour, Jeppe Lerche


    The use of designated emergency teams for cardiac arrest and trauma patients is widely implemented. However, the use of designated teams in Danish emergency departments (EDs) has not been investigated. Our aim was to investigate the use and staffing of emergency teams in Danish EDs.......The use of designated emergency teams for cardiac arrest and trauma patients is widely implemented. However, the use of designated teams in Danish emergency departments (EDs) has not been investigated. Our aim was to investigate the use and staffing of emergency teams in Danish EDs....

  19. The potential and flux landscape theory of ecology.

    Directory of Open Access Journals (Sweden)

    Li Xu

    Full Text Available The species in ecosystems are mutually interacting and self sustainable stable for a certain period. Stability and dynamics are crucial for understanding the structure and the function of ecosystems. We developed a potential and flux landscape theory of ecosystems to address these issues. We show that the driving force of the ecological dynamics can be decomposed to the gradient of the potential landscape and the curl probability flux measuring the degree of the breaking down of the detailed balance (due to in or out flow of the energy to the ecosystems. We found that the underlying intrinsic potential landscape is a global Lyapunov function monotonically going down in time and the topology of the landscape provides a quantitative measure for the global stability of the ecosystems. We also quantified the intrinsic energy, the entropy, the free energy and constructed the non-equilibrium thermodynamics for the ecosystems. We studied several typical and important ecological systems: the predation, competition, mutualism and a realistic lynx-snowshoe hare model. Single attractor, multiple attractors and limit cycle attractors emerge from these studies. We studied the stability and robustness of the ecosystems against the perturbations in parameters and the environmental fluctuations. We also found that the kinetic paths between the multiple attractors do not follow the gradient paths of the underlying landscape and are irreversible because of the non-zero flux. This theory provides a novel way for exploring the global stability, function and the robustness of ecosystems.

  20. Comparison of the high temperature heat flux sensor to traditional heat flux gages under high heat flux conditions.

    Energy Technology Data Exchange (ETDEWEB)

    Blanchat, Thomas K.; Hanks, Charles R.


    Four types of heat flux gages (Gardon, Schmidt-Boelter, Directional Flame Temperature, and High Temperature Heat Flux Sensor) were assessed and compared under flux conditions ranging between 100-1000 kW/m2, such as those seen in hydrocarbon fire or propellant fire conditions. Short duration step and pulse boundary conditions were imposed using a six-panel cylindrical array of high-temperature tungsten lamps. Overall, agreement between all gages was acceptable for the pulse tests and also for the step tests. However, repeated tests with the HTHFS with relatively long durations at temperatures approaching 1000ÀC showed a substantial decrease (10-25%) in heat flux subsequent to the initial test, likely due to the mounting technique. New HTHFS gages have been ordered to allow additional tests to determine the cause of the flux reduction.

  1. Chemistry of serpentine "polymorphs" in the Pan-African serpentinites from the Eastern Desert of Egypt, with an emphasis on the effect of superimposed thermal metamorphism (United States)

    Surour, Adel A.


    The present work deals with some Pan-African serpentinites of Neoproterozoic age from five localities in the Eastern Desert of Egypt namely, Abu Fannani, Fawakhir, Barramiya, Ras Shait and Wadi Ghadir that derivedmostly from lherzolite to harzburgite protoliths. The M-value of antigorite is anindicator of the metamorphic grade which is lowest at Fawakhir (greenschist facies) and highest at Abu Fannani (lower amphibolite facies). Antigoritization during progressive regional metamorphism at Fawakhir is limited and its M-value is much higher than 8.52 indicating crystallization temperatures of 220-250 °C whereas it is ≥300 °C in the rest. Antigorite recrystallized at T ≈ 400-450 °C in the contact metamorphic aureoles due to the emplacement of post-orogenic leucogranites at Fawakhir and Gebel Ghadir. Towards the contact with the granites, M-value of antigorite is low (6.48) compared to 8.52 in the least recrystallized antigorite due to the thermal effect. Antigorite that forms in the thermal aureoles is characterized by two types of substitution; Tschermak substitution (Al3+ and Cr3+ for Si4+ in the tetrahedral sites and Mg2+ in the octahedral sites) and non-Tschermak substitutionin the octahedral sites (2R3+ = 3R2+). Generally, both ortho- and clinochrysotiles are common with MgO contents of 41-41.13 wt% and 39.38-40.93 wt%, respectively. In addition to chlorite, high- and low-Al lizardites are present with almost constant total iron ( 0.24 cations) as Fe2+(vi) and variable Mg2+. This suggests that significant R3+ in the octahedral sites are mostly occupied by Al3+ and Cr3+ and not iron. In the lizardite structure, there is Tschermak substitution of Si4+ by some trivalent cations in the tetrahedral sites. Using the TEM images, antigorite is distinguishable from chrysotile and they suggest the presence of polyhedral or polygonal serpentine (spherical or circular with alternating sectors of lizardite). Crack-seal microstructures are displayed by chrysotile and

  2. Surface Flux Modeling for Air Quality Applications

    Directory of Open Access Journals (Sweden)

    Limei Ran


    Full Text Available For many gasses and aerosols, dry deposition is an important sink of atmospheric mass. Dry deposition fluxes are also important sources of pollutants to terrestrial and aquatic ecosystems. The surface fluxes of some gases, such as ammonia, mercury, and certain volatile organic compounds, can be upward into the air as well as downward to the surface and therefore should be modeled as bi-directional fluxes. Model parameterizations of dry deposition in air quality models have been represented by simple electrical resistance analogs for almost 30 years. Uncertainties in surface flux modeling in global to mesoscale models are being slowly reduced as more field measurements provide constraints on parameterizations. However, at the same time, more chemical species are being added to surface flux models as air quality models are expanded to include more complex chemistry and are being applied to a wider array of environmental issues. Since surface flux measurements of many of these chemicals are still lacking, resistances are usually parameterized using simple scaling by water or lipid solubility and reactivity. Advances in recent years have included bi-directional flux algorithms that require a shift from pre-computation of deposition velocities to fully integrated surface flux calculations within air quality models. Improved modeling of the stomatal component of chemical surface fluxes has resulted from improved evapotranspiration modeling in land surface models and closer integration between meteorology and air quality models. Satellite-derived land use characterization and vegetation products and indices are improving model representation of spatial and temporal variations in surface flux processes. This review describes the current state of chemical dry deposition modeling, recent progress in bi-directional flux modeling, synergistic model development research with field measurements, and coupling with meteorological land surface models.

  3. CycleFreeFlux: efficient removal of thermodynamically infeasible loops from flux distributions. (United States)

    Desouki, Abdelmoneim Amer; Jarre, Florian; Gelius-Dietrich, Gabriel; Lercher, Martin J


    Constraint-based metabolic modeling methods such as Flux Balance Analysis (FBA) are routinely used to predict metabolic phenotypes, e.g. growth rates, ATP yield or the fitness of gene knockouts. One frequent difficulty of constraint-based solutions is the inclusion of thermodynamically infeasible loops (or internal cycles), which add nonbiological fluxes to the predictions. We propose a simple postprocessing of constraint-based solutions, which removes internal cycles from any given flux distribution [Formula: see text] without disturbing other fluxes not involved in the loops. This new algorithm, termed CycleFreeFlux, works by minimizing the sum of absolute fluxes [Formula: see text] while (i) conserving the exchange fluxes and (ii) using the fluxes of the original solution to bound the new flux distribution. This strategy reduces internal fluxes until at least one reaction of every possible internal cycle is inactive, a necessary and sufficient condition for the thermodynamic feasibility of a flux distribution. If alternative representations of the input flux distribution in terms of elementary flux modes exist that differ in their inclusion of internal cycles, then CycleFreeFlux is biased towards solutions that maintain the direction given by [Formula: see text] and towards solutions with lower total flux [Formula: see text]. Our method requires only one additional linear optimization, making it computationally very efficient compared to alternative strategies. We provide freely available R implementations for the enumeration of thermodynamically infeasible cycles as well as for cycle-free FBA solutions, flux variability calculations and random sampling of solution spaces. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail:

  4. Sensorless Direct Flux Vector Control of Synchronous Reluctance Motors Including Standstill, MTPA and Flux Weakening


    Yousefi-Talouki, Arzhang; Pescetto, Paolo; Pellegrino, Gian-Mario Luigi


    This paper proposes a sensorless direct flux vector control scheme for synchronous reluctance motor drives. Torque is controlled at constant switching frequency, via the closed loop regulation of the stator flux linkage vector and of the current component in quadrature with it, using the stator flux oriented reference frame. A hybrid flux and position observer combines back-electromotive force integration with pulsating voltage injection around zero speed. Around zero speed, the position obse...

  5. Integrated analysis of 454 and Illumina transcriptomic sequencing characterizes carbon flux and energy source for fatty acid synthesis in developing Lindera glauca fruits for woody biodiesel

    National Research Council Canada - National Science Library

    Zixin Lin; Jiyong An; Jia Wang; Jun Niu; Chao Ma; Libing Wang; Guanshen Yuan; Lingling Shi; Lili Liu; Jinsong Zhang; Zhixiang Zhang; Ji Qi; Shanzhi Lin


    Background Lindera glauca fruit with high quality and quantity of oil has emerged as a novel potential source of biodiesel in China, but the molecular regulatory mechanism of carbon flux and energy...

  6. Platinum-Group Minerals in Chromitites of the Niquelândia Layered Intrusion (Central Goias, Brazil: Their Magmatic Origin and Low-Temperature Reworking during Serpentinization and Lateritic Weathering

    Directory of Open Access Journals (Sweden)

    Nelson Angeli


    Full Text Available A variety of platinum-group-minerals (PGM have been found to occur associated with the chromitite and dunite layers in the Niquelândia igneous complex. Two genetically distinct populations of PGM have been identified corresponding to phases crystallized at high temperatures (primary, and others formed or modified during post-magmatic serpentinization and lateritic weathering (secondary. Primary PGM have been found in moderately serpentinized chromitite and dunite, usually included in fresh chromite grains or partially oxidized interstitial sulfides. Due to topographically controlled lateritic weathering, the silicate rocks are totally transformed to a smectite-kaolinite-garnierite-amorphous silica assemblage, while the chromite is changed into a massive aggregate of a spinel phase having low-Mg and a low Fe3+/Fe2+ ratio, intimately associated with Ti-minerals, amorphous Fe-hydroxides, goethite, hematite and magnetite. The PGM in part survive alteration, and in part are corroded as a result of deep chemical weathering. Laurite is altered to Ru-oxides or re-crystallizes together with secondary Mg-ilmenite. Other PGM, especially the Pt-Fe alloys, re-precipitate within the altered chromite together with kaolinite and Fe-hydroxides. Textural evidence suggests that re-deposition of secondary PGM took place during chromite alteration, controlled by variation of the redox conditions on a microscopic scale.

  7. Emergency teams in Danish emergency departments

    DEFF Research Database (Denmark)

    Lafrenz, Thomas; Lindberg, Søren Østergaard; La Cour, Jeppe Lerche


    The use of designated emergency teams for cardiac arrest and trauma patients is widely implemented. However, the use of designated teams in Danish emergency departments (EDs) has not been investigated. Our aim was to investigate the use and staffing of emergency teams in Danish EDs....

  8. Prediction of metabolic fluxes by incorporating genomic context and flux-converging pattern analyses. (United States)

    Park, Jong Myoung; Kim, Tae Yong; Lee, Sang Yup


    Flux balance analysis (FBA) of a genome-scale metabolic model allows calculation of intracellular fluxes by optimizing an objective function, such as maximization of cell growth, under given constraints, and has found numerous applications in the field of systems biology and biotechnology. Due to the underdetermined nature of the system, however, it has limitations such as inaccurate prediction of fluxes and existence of multiple solutions for an optimal objective value. Here, we report a strategy for accurate prediction of metabolic fluxes by FBA combined with systematic and condition-independent constraints that restrict the achievable flux ranges of grouped reactions by genomic context and flux-converging pattern analyses. Analyses of three types of genomic contexts, conserved genomic neighborhood, gene fusion events, and co-occurrence of genes across multiple organisms, were performed to suggest a group of fluxes that are likely on or off simultaneously. The flux ranges of these grouped reactions were constrained by flux-converging pattern analysis. FBA of the Escherichia coli genome-scale metabolic model was carried out under several different genotypic (pykF, zwf, ppc, and sucA mutants) and environmental (altered carbon source) conditions by applying these constraints, which resulted in flux values that were in good agreement with the experimentally measured (13)C-based fluxes. Thus, this strategy will be useful for accurately predicting the intracellular fluxes of large metabolic networks when their experimental determination is difficult.

  9. Theoretical models of flux pinning and flux motion in high-{Tc} superconducting oxides

    Energy Technology Data Exchange (ETDEWEB)

    Welch, D.O.


    Various issues involved in the development of phenomenological models of flux pinning and motion in high-{Tc} oxides are discussed. A simplified model is presented for the critical current density and is used to examine the question of whether flux flow results from an instability due to plasticity of the flux-line array or from pin breaking.

  10. Flux Modulation in the Electrodynamic Loudspeaker

    DEFF Research Database (Denmark)

    Halvorsen, Morten; Tinggaard, Carsten; Agerkvist, Finn T.


    This paper discusses the effect of flux modulation in the electrodynamic loudspeaker with main focus on the effect on the force factor. A measurement setup to measure the AC flux modulation with static voice coil is explained and the measurements shows good consistency with FEA simulations. Measu...

  11. On flux terms in volume averaging

    NARCIS (Netherlands)

    Chu, S.G.; Prosperetti, Andrea


    This note examines the modeling of non-convective fluxes (e.g., stress, heat flux and others) as they appear in the general, unclosed form of the volume-averaged equations of multiphase flows. By appealing to the difference between slowly and rapidly varying quantities, it is shown that the natural

  12. Surface Flux Modeling for Air Quality Applications (United States)

    For many gasses and aerosols, dry deposition is an important sink of atmospheric mass. Dry deposition fluxes are also important sources of pollutants to terrestrial and aquatic ecosystems. The surface fluxes of some gases, such as ammonia, mercury, and certain volatile organic c...

  13. Heat flux viscosity in collisional magnetized plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Liu, C., E-mail: [Princeton University, Princeton, New Jersey 08544 (United States); Fox, W. [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States); Bhattacharjee, A. [Princeton University, Princeton, New Jersey 08544 (United States); Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States)


    Momentum transport in collisional magnetized plasmas due to gradients in the heat flux, a “heat flux viscosity,” is demonstrated. Even though no net particle flux is associated with a heat flux, in a plasma there can still be momentum transport owing to the velocity dependence of the Coulomb collision frequency, analogous to the thermal force. This heat-flux viscosity may play an important role in numerous plasma environments, in particular, in strongly driven high-energy-density plasma, where strong heat flux can dominate over ordinary plasma flows. The heat flux viscosity can influence the dynamics of the magnetic field in plasmas through the generalized Ohm's law and may therefore play an important role as a dissipation mechanism allowing magnetic field line reconnection. The heat flux viscosity is calculated directly using the finite-difference method of Epperlein and Haines [Phys. Fluids 29, 1029 (1986)], which is shown to be more accurate than Braginskii's method [S. I. Braginskii, Rev. Plasma Phys. 1, 205 (1965)], and confirmed with one-dimensional collisional particle-in-cell simulations. The resulting transport coefficients are tabulated for ease of application.

  14. Metamaterial anisotropic flux concentrators and magnetic arrays

    DEFF Research Database (Denmark)

    Bjørk, Rasmus; Smith, Anders; Bahl, Christian R.H.


    A metamaterial magnetic flux concentrator is investigated in detail in combination with a Halbach cylinder of infinite length. A general analytical solution to the field is determined and the magnetic figure of merit is determined for a Halbach cylinder with a flux concentrator. It is shown...

  15. Flux Noise in a Superconducting Transmission Line (United States)

    Vasko, F. T.


    We study a superconducting transmission line (TL) formed by distributed L C oscillators and excited by external magnetic fluxes which are aroused from random magnetization (A ) placed in substrate or (B ) distributed at interfaces of a two-wire TL. The low-frequency dynamics of a random magnetic field is described based on the diffusion Langevin equation with a short-range source caused by (a ) a random amplitude or (b ) the gradient of magnetization. For a TL modeled as a two-port network with open and shorted ends, the effective magnetic flux at the open end has nonlocal dependency on noise distribution along the TL. The flux-flux correlation function is evaluated and analyzed for the regimes (A a ), (A b ), (B a ), and (B b ). Essential frequency dispersion takes place around the inverse diffusion time of random flux along the TL. Typically, noise effect increases with size faster than the area of the TL. The flux-flux correlator can be verified both via the population relaxation rate of the qubit, which is formed by the Josephson junction shunted by the TL with flux noises, and via random voltage at the open end of the TL.

  16. Fast flux module detection using matroid theory. (United States)

    Reimers, Arne C; Bruggeman, Frank J; Olivier, Brett G; Stougie, Leen


    Flux balance analysis (FBA) is one of the most often applied methods on genome-scale metabolic networks. Although FBA uniquely determines the optimal yield, the pathway that achieves this is usually not unique. The analysis of the optimal-yield flux space has been an open challenge. Flux variability analysis is only capturing some properties of the flux space, while elementary mode analysis is intractable due to the enormous number of elementary modes. However, it has been found by Kelk et al. (2012) that the space of optimal-yield fluxes decomposes into flux modules. These decompositions allow a much easier but still comprehensive analysis of the optimal-yield flux space. Using the mathematical definition of module introduced by Müller and Bockmayr (2013b), we discovered useful connections to matroid theory, through which efficient algorithms enable us to compute the decomposition into modules in a few seconds for genome-scale networks. Using that every module can be represented by one reaction that represents its function, in this article, we also present a method that uses this decomposition to visualize the interplay of modules. We expect the new method to replace flux variability analysis in the pipelines for metabolic networks.

  17. Heat Flux Distribution of Antarctica Unveiled (United States)

    Martos, Yasmina M.; Catalán, Manuel; Jordan, Tom A.; Golynsky, Alexander; Golynsky, Dmitry; Eagles, Graeme; Vaughan, David G.


    Antarctica is the largest reservoir of ice on Earth. Understanding its ice sheet dynamics is crucial to unraveling past global climate change and making robust climatic and sea level predictions. Of the basic parameters that shape and control ice flow, the most poorly known is geothermal heat flux. Direct observations of heat flux are difficult to obtain in Antarctica, and until now continent-wide heat flux maps have only been derived from low-resolution satellite magnetic and seismological data. We present a high-resolution heat flux map and associated uncertainty derived from spectral analysis of the most advanced continental compilation of airborne magnetic data. Small-scale spatial variability and features consistent with known geology are better reproduced than in previous models, between 36% and 50%. Our high-resolution heat flux map and its uncertainty distribution provide an important new boundary condition to be used in studies on future subglacial hydrology, ice sheet dynamics, and sea level change.

  18. Anthropogenic Heat Flux Estimation from Space: Results of the second phase of the URBANFLUXES Project (United States)

    Chrysoulakis, Nektarios; Marconcini, Mattia; Gastellu-Etchegorry, Jean-Philippe; Grimmond, Sue; Feigenwinter, Christian; Lindberg, Fredrik; Del Frate, Fabio; Klostermann, Judith; Mitraka, Zina; Esch, Thomas; Landier, Lucas; Gabey, Andy; Parlow, Eberhard; Olofson, Frans


    The H2020-Space project URBANFLUXES (URBan ANthrpogenic heat FLUX from Earth observation Satellites) investigates the potential of Copernicus Sentinels to retrieve anthropogenic heat flux, as a key component of the Urban Energy Budget (UEB). URBANFLUXES advances the current knowledge of the impacts of UEB fluxes on urban heat island and consequently on energy consumption in cities. In URBANFLUXES, the anthropogenic heat flux is estimated as a residual of UEB. Therefore, the rest UEB components, namely, the net all-wave radiation, the net change in heat storage and the turbulent sensible and latent heat fluxes are independently estimated from Earth Observation (EO), whereas the advection term is included in the error of the anthropogenic heat flux estimation from the UEB closure. The Discrete Anisotropic Radiative Transfer (DART) model is employed to improve the estimation of the net all-wave radiation balance, whereas the Element Surface Temperature Method (ESTM), adjusted to satellite observations is used to improve the estimation the estimation of the net change in heat storage. Furthermore the estimation of the turbulent sensible and latent heat fluxes is based on the Aerodynamic Resistance Method (ARM). Based on these outcomes, QF is estimated by regressing the sum of the turbulent heat fluxes versus the available energy. In-situ flux measurements are used to evaluate URBANFLUXES outcomes, whereas uncertainties are specified and analyzed. URBANFLUXES is expected to prepare the ground for further innovative exploitation of EO in scientific activities (climate variability studies at local and regional scales) and future and emerging applications (sustainable urban planning, mitigation technologies) to benefit climate change mitigation/adaptation. This study presents the results of the second phase of the project and detailed information on URBANFLUXES is available at:

  19. OpenFLUX: efficient modelling software for 13C-based metabolic flux analysis

    Directory of Open Access Journals (Sweden)

    Nielsen Lars K


    Full Text Available Abstract Background The quantitative analysis of metabolic fluxes, i.e., in vivo activities of intracellular enzymes and pathways, provides key information on biological systems in systems biology and metabolic engineering. It is based on a comprehensive approach combining (i tracer cultivation on 13C substrates, (ii 13C labelling analysis by mass spectrometry and (iii mathematical modelling for experimental design, data processing, flux calculation and statistics. Whereas the cultivation and the analytical part is fairly advanced, a lack of appropriate modelling software solutions for all modelling aspects in flux studies is limiting the application of metabolic flux analysis. Results We have developed OpenFLUX as a user friendly, yet flexible software application for small and large scale 13C metabolic flux analysis. The application is based on the new Elementary Metabolite Unit (EMU framework, significantly enhancing computation speed for flux calculation. From simple notation of metabolic reaction networks defined in a spreadsheet, the OpenFLUX parser automatically generates MATLAB-readable metabolite and isotopomer balances, thus strongly facilitating model creation. The model can be used to perform experimental design, parameter estimation and sensitivity analysis either using the built-in gradient-based search or Monte Carlo algorithms or in user-defined algorithms. Exemplified for a microbial flux study with 71 reactions, 8 free flux parameters and mass isotopomer distribution of 10 metabolites, OpenFLUX allowed to automatically compile the EMU-based model from an Excel file containing metabolic reactions and carbon transfer mechanisms, showing it's user-friendliness. It reliably reproduced the published data and optimum flux distributions for the network under study were found quickly ( Conclusion We have developed a fast, accurate application to perform steady-state 13C metabolic flux analysis. OpenFLUX will strongly facilitate and

  20. Emergency Medical Services (United States)

    ... and need help right away, you should use emergency medical services. These services use specially trained people ... facilities. You may need care in the hospital emergency room (ER). Doctors and nurses there treat emergencies, ...

  1. Emergency Contraception Website (United States)

    Text Only Full media Version Get Emergency Contraception NOW INFO about Emergency Contraception Q&A about Emergency Contraception Español | Arabic Find a Morning After Pill Provider Near You This ...

  2. A Serpentine Way to Signaling

    Indian Academy of Sciences (India) Keywords. Receptor; GPCR; crystal structure; drug discovery. Author Affiliations. Vignesh Narayanan Hariharan Raji R Nair Deepak Kumar Saini1. Department of Molecular Reproduction Development and Genetics Indian Institute of Science Bangalore 560 012, ...

  3. A Serpentine Way to Signaling

    Indian Academy of Sciences (India)

    IAS Admin

    Parkinson's. Serotonin (5HT) receptor. Schizophrenia, Autism. Risperidone,. Depression, Migraine. Rizatriptan. Adenosine (P2Y) receptor. Coronary artery disease. Clopidogrel. Cerebro vascular disease. Box 2. GPCRs as Drug Targets: The Top Sellers. Suggested Reading. [1]. A H Maehle, C R Prull and R F Halliwell, The ...

  4. Emerging Pathogens Initiative (EPI) (United States)

    Department of Veterans Affairs — The Emerging Pathogens Initiative (EPI) database contains emerging pathogens information from the local Veterans Affairs Medical Centers (VAMCs). The EPI software...

  5. Topology of magnetic flux ropes and formation of fossil flux transfer events and boundary layer plasmas (United States)

    Lee, L. C.; Ma, Z. W.; Fu, Z. F.; Otto, A.


    A mechanism for the formation of fossil flux transfer events and the low-level boundary layer within the framework of multiple X-line reconnection is proposed. Attention is given to conditions for which the bulk of magnetic flux in a flux rope of finite extent has a simple magnetic topology, where the four possible connections of magnetic field lines are: IMF to MSP, MSP to IMF, IMF to IMF, and MSP to MSP. For a sufficient relative shift of the X lines, magnetic flux may enter a flux rope from the magnetosphere and exit into the magnetosphere. This process leads to the formation of magnetic flux ropes which contain a considerable amount of magnetosheath plasma on closed magnetospheric field lines. This process is discussed as a possible explanation for the formation of fossil flux transfer events in the magnetosphere and the formation of the low-latitude boundary layer.

  6. Landscape and flux theory of non-equilibrium open economy (United States)

    Zhang, Kun; Wang, Jin


    The economy is open and never in true equilibrium due to the exchanges with outside. However, most of the quantitative studies have been focused on the equilibrium economy. Despite of the recent efforts, it is still challenging to formulate a quantitative theory for uncovering the principles of non-equilibrium open economy. In this study, we developed a landscape and flux theory for non-equilibrium economy. We quantified the states of economy and identify the multi-stable states as the basins of attractions on the underlying landscape. We found the global driving force of the non-equilibrium economy is determined by both the underlying landscape gradient and the curl probability flux measuring the degree of non-equilibriumness through the detailed balance breaking. The non-equilibrium thermodynamics, the global stability, the optimal path and speed of the non-equilibrium economy can be formulated and quantified. In the conventional economy, the supply and demand usually has only one equilibrium. By considering nonlinear supply-demand dynamics, we found that both bi-stable states and limit cycle oscillations can emerge. By shifting the slope of demand curve, we can see how the bi-stability transforms to the limit cycle dynamics and vice versa. By parallel shifting the demand curve, we can also see how the monopoly, the competition, and the bistable monopoly and competition states emerge and transform to one other. We can also see how the mono-stable monopoly, the limit cycle and the mono-stable competition states emerge and transform to one another.

  7. Benthic fluxes in San Francisco Bay (United States)

    Hammond, Douglas E.; Fuller, C.; Harmon, D.; Hartman, Blayne; Korosec, M.; Miller, L.G.; Rea, R.; Warren, S.; Berelson, W.; Hager, S.W.


    Measurements of benthic fluxes have been made on four occasions between February 1980 and February 1981 at a channel station and a shoal station in South San Francisco Bay, using in situ flux chambers. On each occasion replicate measurements of easily measured substances such as radon, oxygen, ammonia, and silica showed a variability (??1??) of 30% or more over distances of a few meters to tens of meters, presumably due to spatial heterogeneity in the benthic community. Fluxes of radon were greater at the shoal station than at the channel station because of greater macrofaunal irrigation at the former, but showed little seasonal variability at either station. At both stations fluxes of oxygen, carbon dioxide, ammonia, and silica were largest following the spring bloom. Fluxes measured during different seasons ranged over factors of 2-3, 3, 4-5, and 3-10 (respectively), due to variations in phytoplankton productivity and temperature. Fluxes of oxygen and carbon dioxide were greater at the shoal station than at the channel station because the net phytoplankton productivity is greater there and the organic matter produced must be rapidly incorporated in the sediment column. Fluxes of silica were greater at the shoal station, probably because of the greater irrigation rates there. N + N (nitrate + nitrite) fluxes were variable in magnitude and in sign. Phosphate fluxes were too small to measure accurately. Alkalinity fluxes were similar at the two stations and are attributed primarily to carbonate dissolution at the shoal station and to sulfate reduction at the channel station. The estimated average fluxes into South Bay, based on results from these two stations over the course of a year, are (in mmol m-2 d-1): O2 = -27 ?? 6; TCO2 = 23 ?? 6; Alkalinity = 9 ?? 2; N + N = -0.3 ?? 0.5; NH3 = 1.4 ?? 0.2; PO4 = 0.1 ?? 0.4; Si = 5.6 ?? 1.1. These fluxes are comparable in magnitude to those in other temperate estuaries with similar productivity, although the seasonal

  8. CO2 flux geothermometer for geothermal exploration (United States)

    Harvey, M. C.; Rowland, J. V.; Chiodini, G.; Rissmann, C. F.; Bloomberg, S.; Fridriksson, T.; Oladottir, A. A.


    A new geothermometer (TCO2 Flux) is proposed based on soil diffuse CO2 flux and shallow temperature measurements made on areas of steam heated, thermally altered ground above active geothermal systems. This CO2 flux geothermometer is based on a previously reported CO2 geothermometer that was designed for use with fumarole analysis. The new geothermometer provides a valuable additional exploration tool for estimating subsurface temperatures in high-temperature geothermal systems. Mean TCO2 Flux estimates fall within the range of deep drill hole temperatures at Wairakei (New Zealand), Tauhara (New Zealand), Rotokawa (New Zealand), Ohaaki (New Zealand), Reykjanes (Iceland) and Copahue (Argentina). The spatial distribution of geothermometry estimates is consistent with the location of major upflow zones previously reported at the Wairakei and Rotokawa geothermal systems. TCO2 Flux was also evaluated at White Island (New Zealand) and Reporoa (New Zealand), where limited sub-surface data exists. Mode TCO2 Flux at White Island is high (320 °C), the highest of the systems considered in this study. However, the geothermometer relies on mineral-water equilibrium in neutral pH reservoir fluids, and would not be reliable in such an active and acidic environment. Mean TCO2 Flux at Reporoa (310 °C) is high, which indicates Reporoa has a separate upflow from the nearby Waiotapu geothermal system; an outflow from Waiotapu would not be expected to have such high temperature.

  9. A time-varying magnetic flux concentrator (United States)

    Kibret, B.; Premaratne, M.; Lewis, P. M.; Thomson, R.; Fitzgerald, P. B.


    It is known that diverse technological applications require the use of focused magnetic fields. This has driven the quest for controlling the magnetic field. Recently, the principles in transformation optics and metamaterials have allowed the realization of practical static magnetic flux concentrators. Extending such progress, here, we propose a time-varying magnetic flux concentrator cylindrical shell that uses electric conductors and ferromagnetic materials to guide magnetic flux to its center. Its performance is discussed based on finite-element simulation results. Our proposed design has potential applications in magnetic sensors, medical devices, wireless power transfer, and near-field wireless communications.

  10. Eddy Correlation Flux Measurement System (ECOR) Handbook

    Energy Technology Data Exchange (ETDEWEB)

    Cook, DR


    The eddy correlation (ECOR) flux measurement system provides in situ, half-hour measurements of the surface turbulent fluxes of momentum, sensible heat, latent heat, and carbon dioxide (CO2) (and methane at one Southern Great Plains extended facility (SGP EF) and the North Slope of Alaska Central Facility (NSA CF). The fluxes are obtained with the eddy covariance technique, which involves correlation of the vertical wind component with the horizontal wind component, the air temperature, the water vapor density, and the CO2 concentration.

  11. A magnetoelectric flux gate: new approach for weak DC magnetic field detection. (United States)

    Chu, Zhaoqiang; Shi, Huaduo; PourhosseiniAsl, Mohammad Javad; Wu, Jingen; Shi, Weiliang; Gao, Xiangyu; Yuan, Xiaoting; Dong, Shuxiang


    The magnetic flux gate sensors based on Faraday's Law of Induction are widely used for DC or extremely low frequency magnetic field detection. Recently, as the fast development of multiferroics and magnetoelectric (ME) composite materials, a new technology based on ME coupling effect is emerging for potential devices application. Here, we report a magnetoelectric flux gate sensor (MEFGS) for weak DC magnetic field detection for the first time, which works on a similar magnetic flux gate principle, but based on ME coupling effect. The proposed MEFGS has a shuttle-shaped configuration made of amorphous FeBSi alloy (Metglas) serving as both magnetic and magnetostrictive cores for producing a closed-loop high-frequency magnetic flux and also a longitudinal vibration, and one pair of embedded piezoelectric PMN-PT fibers ([011]-oriented Pb(Mg,Nb)O3-PbTiO3 single crystal) serving as ME flux gate in a differential mode for detecting magnetic anomaly. In this way, the relative change in output signal of the MEFGS under an applied DC magnetic anomaly of 1 nT was greatly enhanced by a factor of 4 to 5 in comparison with the previous reports. The proposed ME flux gate shows a great potential for magnetic anomaly detections, such as magnetic navigation, magnetic based medical diagnosis, etc.

  12. The continuous UV flux of Alpha Lyrae - Non-LTE results (United States)

    Snijders, M. A. J.


    Non-LTE calculations for the ultraviolet C I and Si I continuous opacity show that LTE results overestimate the importance of these sources of opacity and underestimate the emergent flux in Alpha Lyr. The largest errors occur between 1100 and 1160 A, where the predicted flux in non-LTE is as much as 50 times larger than in LTE, in reasonable accord with Copernicus observations. The discrepancy between LTE models and observations has been interpreted to result from the existence of a chromosphere. Until a self-consistent non-LTE model atmosphere becomes available, such an interpretation is premature.

  13. The impact of sheep pasturing on the energy and organic nutrients levels in the steppe vegetation of the Mohelno Serpentine Steppe National Natural Reserve

    Directory of Open Access Journals (Sweden)

    Pavel Veselý


    Full Text Available The aim of this research was to assess the implications of sheep grazing for the nutritional value of the vegetation in the Mohelno Serpentine Steppe National Nature Reserve (NNR. A free pasture controlled by an electric fence was practised from 1997 to 1998. The German Merino sheep were grazing on an area of 4.25 and 6 ha with a pasture load of 6.8–9.4 sheep per 1 ha in 1997 and 6.7–8.7 sheep per 1 ha in 1998. The steppe vegetation samples were collected from five different sites reflecting the phytocenological composition typical of the individual steppe areas. The vegetation samples were collected on an area of 3×1 m2 during the growing season at two-week intervals. The collected samples were tested for the amount of dry matter, fibre, nitrogenous substances, fat, ash, nitrogen-free extractive substances (NFES, gross energy (GE, metabolic energy (ME, lactation net energy (LNE, fattening net energy (FNE, PDIN and PDIE (PDI – referring to the factually digestible nitrogenous substances in the small intestine of the ruminants. During pasture there was a decrease in the dry matter levels but its average levels remained high (35.45–46.78%. The effect on the nitrogenous levels became apparent (P < 0.05 mainly in the second year of grazing (10.00–10.94% compared to 11.64–19.35% in the vege­tation dry matter. However, in comparison with the pasture vegetation the effect remained less significant. A similar situation was observed in relation to the fluctuation of PDIN and PDIE (64.60–70.71 compared to 75.18–124.98 g/kg of the dry matter and 79.03–82.71 compared to 89.41–29.27 g/kg of the dry matter respectively. The fat levels (3.80–4.02% were not affected by the site (P < 0.05 but the specific utilization. The grazing brought about a marked increase in the fat levels (P < 0.001. The amount of the fibre during the first year was affected only in terms of its decreased site variability (29.60–31.31%. The conclusive evidence (P

  14. An improved flux-step method to determine the critical flux and the critical flux for irreversibility in a membrane bioreactor

    NARCIS (Netherlands)

    Marel, van der P.; Zwijnenburg, A.; Kemperman, A.; Wessling, M.; Temmink, B.G.; Meer, van der W.


    An improved flux-step method is presented incorporating cleaning steps by relaxation to determine the critical flux and the critical flux for irreversibility. Experiments are performed with activated sludge fed with real municipal wastewater. The improved flux-step method is compared with a common

  15. Pediatric ocular emergencies. (United States)

    Hamilton, H L


    There are few ocular emergencies that are unique to the pediatric patient. Most ocular emergencies are traumatic in origin, and the prognosis is often determined by the extent of the injury. Some congenital anomalies that may present as ocular emergencies are also discussed. The focus of this article is recognition and initial therapy for the more common pediatric ocular emergencies.

  16. Reconciling heat-flux and salt-flux estimates at a melting ice-ocean interface

    CERN Document Server

    Keitzl, Thomas; Notz, Dirk


    The ratio of heat and salt flux is employed in ice-ocean models to represent ice-ocean interactions. In this study, this flux ratio is determined from direct numerical simulations of free convection beneath a melting, horizontal, smooth ice-ocean interface. We find that the flux ratio at the interface is three times as large as previously assessed based on turbulent-flux measurements in the field. As a consequence, interface salinities and melt rates are overestimated by up to 40\\% if they are based on the three-equation formulation. We also find that the interface flux ratio depends only very weakly on the far-field conditions of the flow. Lastly, our simulations indicate that estimates of the interface flux ratio based on direct measurements of the turbulent fluxes will be difficult because at the interface the diffusivities alone determine the mixing and the flux ratio varies with depth. As an alternative, we present a consistent evaluation of the flux ratio based on the total heat and salt fluxes across t...

  17. Factors controlling vertical fluxes of prrticles in the Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Nair, T.M.B.; Ramaswamy, V.; Parthiban, G.; Shankar, R.

    whereas organic carbon percentages decreased. Particle flux patterns show a strong seasonality with peak fluxes during the southwest (SW) monsoon (June to September). Relatively high fluxes were also observed during the northeast (NE) monsoon (December...

  18. Accuracy of surface heat fluxes from observations of operational satellites

    Digital Repository Service at National Institute of Oceanography (India)

    Pankajakshan, T.; Sugimori, Y.

    Uncertainties in the flux estimates, resulting from the use of bulk method and remotely sensed data are worked out and are presented for individual and total fluxes. These uncertainties in satellite derived fluxes are further compared...

  19. MHD simulations of the eruption of prominence hosting coronal flux ropes (United States)

    Fan, Yuhong


    We present MHD simulations of the eruption of a prominence hosting coronal flux rope under a coronal streamer, with the thermodynamic treatment including a simple empirical coronal heating, optically thin radiative cooling and the field aligned thermal conduction. We first initialize a quasi-steady solar wind solution with a coronal helmet streamer, using an initial normal flux distribution of a simple bipolar arcade field on the lower boundary. Then into this coronal streamer with an ambient solar wind we impose at the lower boundary the slow emergence of a twisted magnetic torus. As a result a quasi-equilibrium flux rope is built up under the streamer magnetic field. With varying sizes of the streamer and the different length and total twist of the emerged flux rope, we found different scenarios for the evolution from quasi-equilibrium to loss of confinement and eruption. In the case with a broad streamer with slow decline of the overlying field, the flux rope remains well confined until there is sufficient twist such that it first develops the kink instability and evolves through a sequence of kinked, confined states with its apex rises slowly. It eventually develops a “hernia-like” eruption when the kinked apex reaches a certain height and can no-longer be confined. We find that for the long, significantly twisted flux ropes, prominence condensations form in the dips of the twisted field lines due to run-away radiative cooling. Once formed, the prominence carrying field becomes significantly non force-free due to the prominence weight despite being low plasma β. As the flux rope erupts, we also obtain the eruption of the prominence, which shows substantial draining along the legs of the erupting flux rope during the eruption. The prominence may not show a kinked morphology even the flux rope becomes kinked. On the other hand in the case with a narrower streamer, the flux rope with less than 1 wind of twist can erupt via the onset of the torus instability.

  20. On the Taxonomy of Flux Vacua

    Energy Technology Data Exchange (ETDEWEB)

    Giryavets, Alexander


    We investigate several predictions about the properties of IIB flux vacua on Calabi-Yau orientifolds, by constructing and characterizing a very large set of vacua in a specific example, an orientifold of the Calabi-Yau hypersurface in WP{sub 1,1,1,1,4}{sup 4}. We find support for the prediction of Ashok and Douglas that the density of vacua on moduli space is governed by det(-R-{omega}) where R and {omega} are curvature and Kaehler forms on the moduli space. The conifold point {psi} = 1 on moduli space therefore serves as an attractor, with a significant fraction of the flux vacua contained in a small neighborhood surrounding {psi} = 1. We also study the functional dependence of the number of flux vacua on the D3 charge in the fluxes, finding simple power law growth.

  1. Tetrakis-amido high flux membranes (United States)

    McCray, S.B.


    Composite RO membranes of a microporous polymeric support and a polyamide reaction product of a tetrakis-aminomethyl compound and a polyacylhalide are disclosed, said membranes exhibiting high flux and good chlorine resistance.

  2. 400 Area/Fast Flux Test Facility (United States)

    Federal Laboratory Consortium — The 400 Area at Hanford is home primarily to the Fast Flux Test Facility (FFTF), a DOE-owned, formerly operating, 400-megawatt (thermal) liquid-metal (sodium)-cooled...

  3. Dynamics of Muscle Microcirculatory and Blood-myocyte O2 Flux During Contractions (United States)

    Poole, David C.; Copp, Steven W.; Hirai, Daniel M.; Musch, Timothy I.


    The O2 requirements of contracting skeletal muscle may increase 100-fold above rest. In 1919 August Krogh’s brilliant insights recognized the capillary as the principal site for this increased blood-myocyte O2 flux. Based on the premise that most capillaries did not sustain RBC flux at rest Krogh proposed that capillary recruitment (i.e., initiation of red blood cell (RBC) flux in previously non-flowing capillaries) increased the capillary surface area available for O2 flux and reduced mean capillary-to-mitochondrial diffusion distances. More modern experimental approaches reveal that most muscle capillaries may support RBC flux at rest. Thus, rather than contraction-induced capillary recruitment per se, increased RBC flux and hematocrit within already-flowing capillaries likely elevate perfusive and diffusive O2 conductances and hence blood-myocyte O2 flux. Additional surface area for O2 exchange is recruited but, crucially, this may occur along the length of already-flowing capillaries (i.e. longitudinal recruitment). Today, the capillary is still considered the principal site for O2 and substrate delivery to contracting skeletal muscle. Indeed, the presence of very low intramyocyte O2 partial pressures (PO2’s) and the absence of PO2 gradients, whilst refuting the relevance of diffusion distances, place an even greater importance on capillary hemodynamics. This emergent picture calls for a paradigm-shift in our understanding of the function of capillaries by de-emphasizing de novo ‘capillary recruitment.’ Diseases such as heart failure impair blood-myocyte O2 flux, in part, by decreasing the proportion of RBC-flowing capillaries. Knowledge of capillary function in healthy muscle is requisite for identification of pathology and efficient design of therapeutic treatments. PMID:21199399

  4. Mold Flux Crystallization and Mold Thermal Behavior (United States)

    Peterson, Elizabeth Irene

    Mold flux plays a small but critical role in the continuous casting of steel. The carbon-coated powder is added at the top of the water-cooled copper mold, over time it melts and infiltrates the gap between the copper mold and the solidifying steel strand. Mold powders serve five primary functions: (1) chemical insulation, (2) thermal insulation, (3) lubrication between the steel strand and mold, (4) absorption of inclusions, and (5) promotion of even heat flux. All five functions are critical to slab casting, but surface defect prevention is primarily controlled through even heat flux. Glassy fluxes have high heat transfer and result in a thicker steel shell. Steels with large volumetric shrinkage on cooling must have a crystalline flux to reduce the radiative heat transfer and avoid the formation of cracks in the shell. Crystallinity plays a critical role in steel shell formation, therefore it is important to study the thermal conditions that promote each phase and its morphology. Laboratory tests were performed to generate continuous cooling transformation (CCT) and time-temperature-transformation (TTT) diagrams. Continuous cooling transformation tests were performed in an instrumented eight cell step chill mold. Results showed that cuspidine was the only phase formed in conventional fluxes and all observed structures were dendritic. An isothermal tin bath quench method was also developed to isothermally age glassy samples. Isothermal tests yielded different microstructures and different phases than those observed by continuous cooling. Comparison of aged tests with industrial flux films indicates similar faceted structures along the mold wall, suggesting that mold flux first solidifies as a glass along the mold wall, but the elevated temperature devitrifies the glassy structure forming crystals that cannot form by continuous cooling.

  5. Recurrence Analysis of Eddy Covariance Fluxes (United States)

    Lange, Holger; Flach, Milan; Foken, Thomas; Hauhs, Michael


    The eddy covariance (EC) method is one key method to quantify fluxes in biogeochemical cycles in general, and carbon and energy transport across the vegetation-atmosphere boundary layer in particular. EC data from the worldwide net of flux towers (Fluxnet) have also been used to validate biogeochemical models. The high resolution data are usually obtained at 20 Hz sampling rate but are affected by missing values and other restrictions. In this contribution, we investigate the nonlinear dynamics of EC fluxes using Recurrence Analysis (RA). High resolution data from the site DE-Bay (Waldstein-Weidenbrunnen) and fluxes calculated at half-hourly resolution from eight locations (part of the La Thuile dataset) provide a set of very long time series to analyze. After careful quality assessment and Fluxnet standard gapfilling pretreatment, we calculate properties and indicators of the recurrent structure based both on Recurrence Plots as well as Recurrence Networks. Time series of RA measures obtained from windows moving along the time axis are presented. Their interpretation is guided by three different questions: (1) Is RA able to discern periods where the (atmospheric) conditions are particularly suitable to obtain reliable EC fluxes? (2) Is RA capable to detect dynamical transitions (different behavior) beyond those obvious from visual inspection? (3) Does RA contribute to an understanding of the nonlinear synchronization between EC fluxes and atmospheric parameters, which is crucial for both improving carbon flux models as well for reliable interpolation of gaps? (4) Is RA able to recommend an optimal time resolution for measuring EC data and for analyzing EC fluxes? (5) Is it possible to detect non-trivial periodicities with a global RA? We will demonstrate that the answers to all five questions is affirmative, and that RA provides insights into EC dynamics not easily obtained otherwise.

  6. OpenFLUX: efficient modelling software for 13C-based metabolic flux analysis. (United States)

    Quek, Lake-Ee; Wittmann, Christoph; Nielsen, Lars K; Krömer, Jens O


    The quantitative analysis of metabolic fluxes, i.e., in vivo activities of intracellular enzymes and pathways, provides key information on biological systems in systems biology and metabolic engineering. It is based on a comprehensive approach combining (i) tracer cultivation on 13C substrates, (ii) 13C labelling analysis by mass spectrometry and (iii) mathematical modelling for experimental design, data processing, flux calculation and statistics. Whereas the cultivation and the analytical part is fairly advanced, a lack of appropriate modelling software solutions for all modelling aspects in flux studies is limiting the application of metabolic flux analysis. We have developed OpenFLUX as a user friendly, yet flexible software application for small and large scale 13C metabolic flux analysis. The application is based on the new Elementary Metabolite Unit (EMU) framework, significantly enhancing computation speed for flux calculation. From simple notation of metabolic reaction networks defined in a spreadsheet, the OpenFLUX parser automatically generates MATLAB-readable metabolite and isotopomer balances, thus strongly facilitating model creation. The model can be used to perform experimental design, parameter estimation and sensitivity analysis either using the built-in gradient-based search or Monte Carlo algorithms or in user-defined algorithms. Exemplified for a microbial flux study with 71 reactions, 8 free flux parameters and mass isotopomer distribution of 10 metabolites, OpenFLUX allowed to automatically compile the EMU-based model from an Excel file containing metabolic reactions and carbon transfer mechanisms, showing it's user-friendliness. It reliably reproduced the published data and optimum flux distributions for the network under study were found quickly (studies. By providing the software open source, we hope it will evolve with the rapidly growing field of fluxomics.

  7. Mathematical Modeling of Electrolyte Flow Dynamic Patterns and Volumetric Flow Penetrations in the Flow Channel over Porous Electrode Layered System in Vanadium Flow Battery with Serpentine Flow Field Design

    CERN Document Server

    Ke, Xinyou; Alexander, J Iwan D; Savinell, Robert F


    In this work, a two-dimensional mathematical model is developed to study the flow patterns and volumetric flow penetrations in the flow channel over the porous electrode layered system in vanadium flow battery with serpentine flow field design. The flow distributions at the interface between the flow channel and porous electrode are examined. It is found that the non-linear pressure distributions can distinguish the interface flow distributions under the ideal plug flow and ideal parabolic flow inlet boundary conditions. However, the volumetric flow penetration within the porous electrode beneath the flow channel through the integration of interface flow velocity reveals that this value is identical under both ideal plug flow and ideal parabolic flow inlet boundary conditions. The volumetric flow penetrations under the advection effects of flow channel and landing/rib are estimated. The maximum current density achieved in the flow battery can be predicted based on the 100% amount of electrolyte flow reactant ...

  8. The SeaFlux Turbulent Flux Dataset Version 1.0 Documentation (United States)

    Clayson, Carol Anne; Roberts, J. Brent; Bogdanoff, Alec S.


    Under the auspices of the World Climate Research Programme (WCRP) Global Energy and Water cycle EXperiment (GEWEX) Data and Assessment Panel (GDAP), the SeaFlux Project was created to investigate producing a high-resolution satellite-based dataset of surface turbulent fluxes over the global oceans. The most current release of the SeaFlux product is Version 1.0; this represents the initial release of turbulent surface heat fluxes, associated near-surface variables including a diurnally varying sea surface temperature.

  9. A finite element calculation of flux pumping (United States)

    Campbell, A. M.


    A flux pump is not only a fascinating example of the power of Faraday’s concept of flux lines, but also an attractive way of powering superconducting magnets without large electronic power supplies. However it is not possible to do this in HTS by driving a part of the superconductor normal, it must be done by exceeding the local critical density. The picture of a magnet pulling flux lines through the material is attractive, but as there is no direct contact between flux lines in the magnet and vortices, unless the gap between them is comparable to the coherence length, the process must be explicable in terms of classical electromagnetism and a nonlinear V–I characteristic. In this paper a simple 2D model of a flux pump is used to determine the pumping behaviour from first principles and the geometry. It is analysed with finite element software using the A formulation and FlexPDE. A thin magnet is passed across one or more superconductors connected to a load, which is a large rectangular loop. This means that the self and mutual inductances can be calculated explicitly. A wide strip, a narrow strip and two conductors are considered. Also an analytic circuit model is analysed. In all cases the critical state model is used, so the flux flow resistivity and dynamic resistivity are not directly involved, although an effective resistivity appears when J c is exceeded. In most of the cases considered here is a large gap between the theory and the experiments. In particular the maximum flux transferred to the load area is always less than the flux of the magnet. Also once the threshold needed for pumping is exceeded the flux in the load saturates within a few cycles. However the analytic circuit model allows a simple modification to allow for the large reduction in I c when the magnet is over a conductor. This not only changes the direction of the pumped flux but leads to much more effective pumping.

  10. Ground State Properties of the 1/2 Flux Harper Hamiltonian (United States)

    Kennedy, Colin; Burton, William Cody; Chung, Woo Chang; Ketterle, Wolfgang


    The Harper Hamiltonian describes the motion of charged particles in an applied magnetic field - the spectrum of which exhibits the famed Hofstadter's butterfly. Recent advances in driven optical lattices have made great strides in simulating nontrivial Hamiltonians, such as the Harper model, in the time-averaged sense. We report on the realization of the ground state of bosons in the Harper Hamiltonian for 1/2 flux per plaquette utilizing a tilted two-dimensional lattice with laser assisted tunneling. We detail progress in studying various ground state properties of the 1/2 flux Harper Hamiltonian including ground state degeneracies, gauge-dependent observables, effects of micromotion, adiabatic loading schemes, and emergence and decay of coherence. Additionally, we describe prospects for flux rectification using a period-tripled superlattice and generalizations to three dimensions. MIT-Harvard Center for Ultracold Atoms, Research Laboratory of Electronics, Department of Physics, Massachusetts Institute of Technology.

  11. Intense CH{sub 4} plumes generated by serpentinization of ultramafic rocks at the intersection of the 15{degree}20[minutes]N fracture zone and the Mid-Atlantic Ridge

    Energy Technology Data Exchange (ETDEWEB)

    Charlou, J.L.; Fouquet, Y.; Bougault, H.; Donval, J.P.; Etoubleau, J. [IFREMER Centre de Brest, Plouzane (France). Dept. Geosciences Marines; Jean-Baptiste, P.; Dapoigny, A. [CEA Saclay, Gif-sur-Yvette (France); Appriou, P. [Univ. de Bretagne Occidentale, Brest (France); Rona, P.A. [Rutgers-the State Univ. of New Jersey, New Brunswick, NJ (United States)


    As part of the FARA French-US Program designed to study the Mid-Atlantic Ridge (MAR) between 15{degree}N and the Azores, twenty-three dives with the submersible Nautile were conducted during the French-US Faranaut 15N cruise on the eastern and western parts of the Fracture Zone/Ridge axis intersection. South of the eastern ridge-transform fault intersection, nine Nautile dives were made within the rift valley and along the western rift valley wall. CH{sub 4} concentrations in the bottom waters reach 53.2 nmol/kg along faulted zones on top and on the east flank of the ultramafic inner corner high where serpentinized rocks outcrop. No {sup 3}He anomaly is associated with methane, ruling out any primary mantle component. High CH{sub 4} anomalies (up to 22 nmol/kg) are also present in the bottom waters of the rift valley northern segment on both the western and eastern valley walls and on the inner high adjacent to the eastern wall where ultramafic rocks outcrop. Seven vertical hydrocasts carried out in the axial valley (4500 M deep) show an intense CH{sub 4} anomaly, with a maximum (35.8 nmol/kg) at 3200 m depth. CH{sub 4} concentrations of 9.9--14.9 nmol/kg are also present on the western wall along the 3200 m isobath. CH{sub 4} output from ultramafic outcrops on the western and eastern intersections of the Fracture Zone with the MAR is believed to reflect ongoing serpentinization.

  12. Derivative processes for modelling metabolic fluxes (United States)

    Žurauskienė, Justina; Kirk, Paul; Thorne, Thomas; Pinney, John; Stumpf, Michael


    Motivation: One of the challenging questions in modelling biological systems is to characterize the functional forms of the processes that control and orchestrate molecular and cellular phenotypes. Recently proposed methods for the analysis of metabolic pathways, for example, dynamic flux estimation, can only provide estimates of the underlying fluxes at discrete time points but fail to capture the complete temporal behaviour. To describe the dynamic variation of the fluxes, we additionally require the assumption of specific functional forms that can capture the temporal behaviour. However, it also remains unclear how to address the noise which might be present in experimentally measured metabolite concentrations. Results: Here we propose a novel approach to modelling metabolic fluxes: derivative processes that are based on multiple-output Gaussian processes (MGPs), which are a flexible non-parametric Bayesian modelling technique. The main advantages that follow from MGPs approach include the natural non-parametric representation of the fluxes and ability to impute the missing data in between the measurements. Our derivative process approach allows us to model changes in metabolite derivative concentrations and to characterize the temporal behaviour of metabolic fluxes from time course data. Because the derivative of a Gaussian process is itself a Gaussian process, we can readily link metabolite concentrations to metabolic fluxes and vice versa. Here we discuss how this can be implemented in an MGP framework and illustrate its application to simple models, including nitrogen metabolism in Escherichia coli. Availability and implementation: R code is available from the authors upon request. Contact:; Supplementary information: Supplementary data are available at Bioinformatics online. PMID:24578401

  13. OEM Emergency Preparedness Information (United States)

    U.S. Environmental Protection Agency — The Office of Emergency Management compiles a wide variety of information in support of Emergency Preparedness, including certain elements of the System for Risk...

  14. Emergency airway puncture - slideshow (United States)

    ... this page: // Emergency airway puncture - series—Normal anatomy To use the ... 2016 Updated by: Jacob L. Heller, MD, MHA, Emergency Medicine, Virginia Mason Medical Center, Seattle, WA. Also ...

  15. Costs of Emergency Care (United States)

    American College of Emergency Physicians | News Room - Fact Sheets Newsroom Site Navigation News Releases Get News Alerts by Email All RSS Feeds ACEP ... Contact Us Site Body Main Content Annals of Emergency Medicine | EMAF Website | ACEP Policy Statements | ACEP Now | ...

  16. Emergency airway puncture (United States)

    ... this page: // Emergency airway puncture To use the sharing features on this page, please enable JavaScript. Emergency airway puncture is the placement of a hollow ...

  17. Historicism and Industry Emergence

    DEFF Research Database (Denmark)

    Kirsch, David; Moeen, Mahka; Wadhwani, Dan


    Management and organization scholars have increasingly turned to historical sources to examine the emergence and evolution of industries over time. This scholarship has typically used historical evidence as observations for testing theoretically relevant processes of industry emergence. In this c...

  18. Dog Bite Emergencies (United States)

    ... Emergency Care Animal Welfare Veterinary Careers Public Health Dog bite emergencies What do I do if I’ ... vaccination records. What do I do if my dog bites someone? Dog bites are scary for everyone ...

  19. CO2 flux from Javanese mud volcanism (United States)

    Queißer, M.; Burton, M. R.; Arzilli, F.; Chiarugi, A.; Marliyani, G. I.; Anggara, F.; Harijoko, A.


    Studying the quantity and origin of CO2 emitted by back-arc mud volcanoes is critical to correctly model fluid-dynamical, thermodynamical, and geochemical processes that drive their activity and to constrain their role in the global geochemical carbon cycle. We measured CO2 fluxes of the Bledug Kuwu mud volcano on the Kendeng Fold and thrust belt in the back arc of Central Java, Indonesia, using scanning remote sensing absorption spectroscopy. The data show that the expelled gas is rich in CO2 with a volume fraction of at least 16 vol %. A lower limit CO2 flux of 1.4 kg s-1 (117 t d-1) was determined, in line with the CO2 flux from the Javanese mud volcano LUSI. Extrapolating these results to mud volcanism from the whole of Java suggests an order of magnitude total CO2 flux of 3 kt d-1, comparable with the expected back-arc efflux of magmatic CO2. After discussing geochemical, geological, and geophysical evidence we conclude that the source of CO2 observed at Bledug Kuwu is likely a mixture of thermogenic, biogenic, and magmatic CO2, with faulting controlling potential pathways for magmatic fluids. This study further demonstrates the merit of man-portable active remote sensing instruments for probing natural gas releases, enabling bottom-up quantification of CO2 fluxes.

  20. CO2 flux from Javanese mud volcanism. (United States)

    Queißer, M; Burton, M R; Arzilli, F; Chiarugi, A; Marliyani, G I; Anggara, F; Harijoko, A


    Studying the quantity and origin of CO2 emitted by back-arc mud volcanoes is critical to correctly model fluid-dynamical, thermodynamical, and geochemical processes that drive their activity and to constrain their role in the global geochemical carbon cycle. We measured CO2 fluxes of the Bledug Kuwu mud volcano on the Kendeng Fold and thrust belt in the back arc of Central Java, Indonesia, using scanning remote sensing absorption spectroscopy. The data show that the expelled gas is rich in CO2 with a volume fraction of at least 16 vol %. A lower limit CO2 flux of 1.4 kg s-1 (117 t d-1) was determined, in line with the CO2 flux from the Javanese mud volcano LUSI. Extrapolating these results to mud volcanism from the whole of Java suggests an order of magnitude total CO2 flux of 3 kt d-1, comparable with the expected back-arc efflux of magmatic CO2. After discussing geochemical, geological, and geophysical evidence we conclude that the source of CO2 observed at Bledug Kuwu is likely a mixture of thermogenic, biogenic, and magmatic CO2, with faulting controlling potential pathways for magmatic fluids. This study further demonstrates the merit of man-portable active remote sensing instruments for probing natural gas releases, enabling bottom-up quantification of CO2 fluxes.

  1. T2K neutrino flux prediction (United States)

    Abe, K.; Abgrall, N.; Aihara, H.; Akiri, T.; Albert, J. B.; Andreopoulos, C.; Aoki, S.; Ariga, A.; Ariga, T.; Assylbekov, S.; Autiero, D.; Barbi, M.; Barker, G. J.; Barr, G.; Bass, M.; Batkiewicz, M.; Bay, F.; Bentham, S. W.; Berardi, V.; Berger, B. E.; Berkman, S.; Bertram, I.; Beznosko, D.; Bhadra, S.; Blaszczyk, F. d. M.; Blondel, A.; Bojechko, C.; Boyd, S.; Bravar, A.; Bronner, C.; Brook-Roberge, D. G.; Buchanan, N.; Calland, R. G.; Caravaca Rodríguez, J.; Cartwright, S. L.; Castillo, R.; Catanesi, M.-G.; Cervera, A.; Cherdack, D.; Christodoulou, G.; Clifton, A.; Coleman, J.; Coleman, S. J.; Collazuol, G.; Connolly, K.; Curioni, A.; Dabrowska, A.; Danko, I.; Das, R.; Davis, S.; Day, M.; de André, J. P. A. M.; de Perio, P.; De Rosa, G.; Dealtry, T.; Densham, C.; Di Lodovico, F.; Di Luise, S.; Dobson, J.; Duboyski, T.; Dufour, F.; Dumarchez, J.; Dytman, S.; Dziewiecki, M.; Dziomba, M.; Emery, S.; Ereditato, A.; Escudero, L.; Esposito, L. S.; Finch, A. J.; Frank, E.; Friend, M.; Fujii, Y.; Fukuda, Y.; Galymov, V.; Gaudin, A.; Giffin, S.; Giganti, C.; Gilje, K.; Golan, T.; Gomez-Cadenas, J. J.; Gonin, M.; Grant, N.; Gudin, D.; Guzowski, P.; Hadley, D. R.; Haesler, A.; Haigh, M. D.; Hansen, D.; Hara, T.; Hartz, M.; Hasegawa, T.; Hastings, N. C.; Hayato, Y.; Hearty, C.; Helmer, R. L.; Hignight, J.; Hillairet, A.; Himmel, A.; Hiraki, T.; Holeczek, J.; Horikawa, S.; Huang, K.; Hyndman, A.; Ichikawa, A. K.; Ieki, K.; Ieva, M.; Ikeda, M.; Imber, J.; Insler, J.; Ishida, T.; Ishii, T.; Ives, S. J.; Iyogi, K.; Izmaylov, A.; Jamieson, B.; Johnson, R. A.; Jo, J. H.; Jonsson, P.; Joo, K. K.; Jover-Manas, G. V.; Jung, C. K.; Kaji, H.; Kajita, T.; Kakuno, H.; Kameda, J.; Kanazawa, Y.; Karlen, D.; Karpikov, I.; Kearns, E.; Khabibullin, M.; Khanam, F.; Khotjantsev, A.; Kielczewska, D.; Kikawa, T.; Kilinski, A.; Kim, J. Y.; Kim, J.; Kim, S. B.; Kirby, B.; Kisiel, J.; Kitching, P.; Kobayashi, T.; Kogan, G.; Konaka, A.; Kormos, L. L.; Korzenev, A.; Koseki, K.; Koshio, Y.; Kowalik, K.; Kreslo, I.; Kropp, W.; Kubo, H.; Kudenko, Y.; Kumaratunga, S.; Kurjata, R.; Kutter, T.; Lagoda, J.; Laihem, K.; Laing, A.; Laveder, M.; Lawe, M.; Lee, K. P.; Licciardi, C.; Lim, I. T.; Lindner, T.; Lister, C.; Litchfield, R. P.; Longhin, A.; Lopez, G. D.; Ludovici, L.; Macaire, M.; Magaletti, L.; Mahn, K.; Malek, M.; Manly, S.; Marchionni, A.; Marino, A. D.; Marteau, J.; Martin, J. F.; Maruyama, T.; Marzec, J.; Masliah, P.; Mathie, E. L.; Matsumura, C.; Matsuoka, K.; Matveev, V.; Mavrokoridis, K.; Mazzucato, E.; McCauley, N.; McFarland, K. S.; McGrew, C.; McLachlan, T.; Messina, M.; Metelko, C.; Mezzetto, M.; Mijakowski, P.; Miller, C. A.; Minamino, A.; Mineev, O.; Mine, S.; Missert, A.; Miura, M.; Monfregola, L.; Moriyama, S.; Mueller, Th. A.; Murakami, A.; Murdoch, M.; Murphy, S.; Myslik, J.; Nagasaki, T.; Nakadaira, T.; Nakahata, M.; Nakai, T.; Nakajima, K.; Nakamura, K.; Nakayama, S.; Nakaya, T.; Nakayoshi, K.; Naples, D.; Nicholls, T. C.; Nielsen, C.; Nishikawa, K.; Nishimura, Y.; O'Keeffe, H. M.; Obayashi, Y.; Ohta, R.; Okumura, K.; Oryszczak, W.; Oser, S. M.; Otani, M.; Owen, R. A.; Oyama, Y.; Pac, M. Y.; Palladino, V.; Paolone, V.; Payne, D.; Pearce, G. F.; Perevozchikov, O.; Perkin, J. D.; Pinzon Guerra, E. S.; Plonski, P.; Poplawska, E.; Popov, B.; Posiadala, M.; Poutissou, J.-M.; Poutissou, R.; Przewlocki, P.; Quilain, B.; Radicioni, E.; Ratoff, P. N.; Ravonel, M.; Rayner, M. A.; Reeves, M.; Reinherz-Aronis, E.; Retiere, F.; Rodrigues, P. A.; Rondio, E.; Rossi, B.; Roth, S.; Rubbia, A.; Ruterbories, D.; Sacco, R.; Sakashita, K.; Sánchez, F.; Scantamburlo, E.; Scholberg, K.; Schwehr, J.; Scott, M.; Scully, D. I.; Seiya, Y.; Sekiguchi, T.; Sekiya, H.; Shibata, M.; Shiozawa, M.; Short, S.; Shustrov, Y.; Sinclair, P.; Smith, B.; Smith, R. J.; Smy, M.; Sobczyk, J. T.; Sobel, H.; Sorel, M.; Southwell, L.; Stamoulis, P.; Steinmann, J.; Still, B.; Sulej, R.; Suzuki, A.; Suzuki, K.; Suzuki, S. Y.; Suzuki, Y.; Szeglowski, T.; Szeptycka, M.; Tacik, R.; Tada, M.; Takahashi, S.; Takeda, A.; Takeuchi, Y.; Tanaka, H. A.; Tanaka, M.; Tanaka, M. M.; Taylor, I. J.; Terhorst, D.; Terri, R.; Thompson, L. F.; Thorley, A.; Tobayama, S.; Toki, W.; Tomura, T.; Totsuka, Y.; Touramanis, C.; Tsukamoto, T.; Tzanov, M.; Uchida, Y.; Ueno, K.; Vacheret, A.; Vagins, M.; Vasseur, G.; Wachala, T.; Waldron, A. V.; Walter, C. W.; Wang, J.; Wark, D.; Wascko, M. O.; Weber, A.; Wendell, R.; Wikström, G.; Wilkes, R. J.; Wilking, M. J.; Wilkinson, C.; Williamson, Z.; Wilson, J. R.; Wilson, R. J.; Wongjirad, T.; Yamada, Y.; Yamamoto, K.; Yanagisawa, C.; Yano, T.; Yen, S.; Yershov, N.; Yokoyama, M.; Yuan, T.; Zalewska, A.; Zambelli, L.; Zaremba, K.; Ziembicki, M.; Zimmerman, E. D.; Zito, M.; Żmuda, J.


    The Tokai-to-Kamioka (T2K) experiment studies neutrino oscillations using an off-axis muon neutrino beam with a peak energy of about 0.6 GeV that originates at the Japan Proton Accelerator Research Complex accelerator facility. Interactions of the neutrinos are observed at near detectors placed at 280 m from the production target and at the far detector—Super-Kamiokande—located 295 km away. The flux prediction is an essential part of the successful prediction of neutrino interaction rates at the T2K detectors and is an important input to T2K neutrino oscillation and cross section measurements. A FLUKA and GEANT3-based simulation models the physical processes involved in the neutrino production, from the interaction of primary beam protons in the T2K target, to the decay of hadrons and muons that produce neutrinos. The simulation uses proton beam monitor measurements as inputs. The modeling of hadronic interactions is reweighted using thin target hadron production data, including recent charged pion and kaon measurements from the NA61/SHINE experiment. For the first T2K analyses the uncertainties on the flux prediction are evaluated to be below 15% near the flux peak. The uncertainty on the ratio of the flux predictions at the far and near detectors is less than 2% near the flux peak.

  2. Untwisting Jets Related to Magnetic Flux Cancellation (United States)

    Liu, Jiajia; Erdélyi, Robert; Wang, Yuming; Liu, Rui


    The rotational motion of solar jets is believed to be a signature of the untwisting process resulting from magnetic reconnection, which takes place between twisted closed magnetic loops (i.e., magnetic flux ropes) and open magnetic field lines. The identification of the pre-existing flux rope, and the relationship between the twist contained in the rope and the number of turns the jet experiences, are then vital in understanding the jet-triggering mechanism. In this paper, we will perform a detailed analysis of imaging, spectral, and magnetic field observations of four homologous jets, among which the fourth one releases a twist angle of 2.6π. Nonlinear force-free field extrapolation of the photospheric vector magnetic field before the jet eruption presents a magnetic configuration with a null point between twisted and open fields—a configuration highly in favor of the eruption of solar jets. The fact that the jet rotates in the opposite sense of handness to the twist contained in the pre-eruption photospheric magnetic field confirms the unwinding of the twist by the jet’s rotational motion. The temporal relationship between jets’ occurrence and the total negative flux at their source region, together with the enhanced magnetic submergence term of the photospheric Poynting flux, shows that these jets are highly associated with local magnetic flux cancellation.

  3. Emergent biosynthetic capacity in simple microbial communities.

    Directory of Open Access Journals (Sweden)

    Hsuan-Chao Chiu


    Full Text Available Microbes have an astonishing capacity to transform their environments. Yet, the metabolic capacity of a single species is limited and the vast majority of microorganisms form complex communities and join forces to exhibit capabilities far exceeding those achieved by any single species. Such enhanced metabolic capacities represent a promising route to many medical, environmental, and industrial applications and call for the development of a predictive, systems-level understanding of synergistic microbial capacity. Here we present a comprehensive computational framework, integrating high-quality metabolic models of multiple species, temporal dynamics, and flux variability analysis, to study the metabolic capacity and dynamics of simple two-species microbial ecosystems. We specifically focus on detecting emergent biosynthetic capacity--instances in which a community growing on some medium produces and secretes metabolites that are not secreted by any member species when growing in isolation on that same medium. Using this framework to model a large collection of two-species communities on multiple media, we demonstrate that emergent biosynthetic capacity is highly prevalent. We identify commonly observed emergent metabolites and metabolic reprogramming patterns, characterizing typical mechanisms of emergent capacity. We further find that emergent secretion tends to occur in two waves, the first as soon as the two organisms are introduced, and the second when the medium is depleted and nutrients become limited. Finally, aiming to identify global community determinants of emergent capacity, we find a marked association between the level of emergent biosynthetic capacity and the functional/phylogenetic distance between community members. Specifically, we demonstrate a "Goldilocks" principle, where high levels of emergent capacity are observed when the species comprising the community are functionally neither too close, nor too distant. Taken together

  4. A Self-Consistent Numerical Magnetohydrodynamic (MHD) Model of Helmet Streamer and Flux-Rope Interactions: Initiation and Propagation of Coronal Mass Ejections (CMEs) (United States)

    Wu, S. T.; Guo, W. P.


    We present results for an investigation of the interaction of a helmet streamer arcade and a helical flux-rope emerging from the sub-photosphere. These results are obtained by using a three-dimensional axisymmetric, time-dependent ideal magnetohydrodynamic (MHD) model. Because of the physical nature of the flux-rope, we investigate two types of flux-ropes; (1) high density flux-rope (i.e. flux-rope without cavity), and (2) low density flux rope (i.e. flux-rope with cavity). When the streamer is disrupted by the flux-rope, it will evolve into a configuration resembling the typical observed loop-like Coronal Mass Ejection (CMES) for both cases. The streamer-flux rope system with cavity is easier to be disrupted and the propagation speed of the CME is faster than the streamer-flux rope system without cavity. Our results demonstrate that magnetic buoyancy force plays an important role in disrupting the streamer.

  5. TropFlux: air-sea fluxes for the global tropical oceans-description and evaluation

    Digital Repository Service at National Institute of Oceanography (India)

    PraveenKumar, B.; Vialard, J.; Lengaigne, M.; Murty, V.S.N.; McPhaden, M.J.

    This paper evaluates several timely, daily air-sea heat flux products (NCEP, NCEP2, ERA-Interim and OAFlux/ISCCP) against observations and present the newly developed TropFlux product. This new product uses bias-corrected ERA-interim and ISCCP data...

  6. About Merging Threshold and Critical Flux Concepts into a Single One: The Boundary Flux

    Directory of Open Access Journals (Sweden)

    Marco Stoller


    Full Text Available In the last decades much effort was put in understanding fouling phenomena on membranes. One successful approach to describe fouling issues on membranes is the critical flux theory. The possibility to measure a maximum value of the permeate flux for a given system without incurring in fouling issues was a breakthrough in membrane process design. However, in many cases critical fluxes were found to be very low, lower than the economic feasibility of the process. The knowledge of the critical flux value must be therefore considered as a good starting point for process design. In the last years, a new concept was introduced, the threshold flux, which defines the maximum permeate flow rate characterized by a low constant fouling rate regime. This concept, more than the critical flux, is a new practical tool for membrane process designers. In this paper a brief review on critical and threshold flux will be reported and analyzed. And since the concepts share many common aspects, merged into a new concept, called the boundary flux, the validation will occur by the analysis of previously collected data by the authors, during the treatment of olive vegetation wastewater by ultrafiltration and nanofiltration membranes.

  7. Estimating biological elementary flux modes that decompose a flux distribution by the minimal branching property

    DEFF Research Database (Denmark)

    Chan, Siu Hung Joshua; Solem, Christian; Jensen, Peter Ruhdal


    MOTIVATION: Elementary flux mode (EFM) is a useful tool in constraint-based modeling of metabolic networks. The property that every flux distribution can be decomposed as a weighted sum of EFMs allows certain applications of EFMs to studying flux distributions. The existence of biologically infea...... knowledge, which facilitates interpretation. Comparison of the methods applied to a complex flux distribution in Lactococcus lactis similarly showed the advantages of MBD. The minimal branching EFM concept underlying MBD should be useful in other applications.......MOTIVATION: Elementary flux mode (EFM) is a useful tool in constraint-based modeling of metabolic networks. The property that every flux distribution can be decomposed as a weighted sum of EFMs allows certain applications of EFMs to studying flux distributions. The existence of biologically......, i.e. minimal branching. RESULTS: We developed the concept of minimal branching EFM and derived the minimal branching decomposition (MBD) to decompose flux distributions. Testing in the core Escherichia coli metabolic network indicated that MBD can distinguish branches at branch points and greatly...

  8. About merging threshold and critical flux concepts into a single one: the boundary flux. (United States)

    Stoller, Marco; Ochando-Pulido, Javier M


    In the last decades much effort was put in understanding fouling phenomena on membranes. One successful approach to describe fouling issues on membranes is the critical flux theory. The possibility to measure a maximum value of the permeate flux for a given system without incurring in fouling issues was a breakthrough in membrane process design. However, in many cases critical fluxes were found to be very low, lower than the economic feasibility of the process. The knowledge of the critical flux value must be therefore considered as a good starting point for process design. In the last years, a new concept was introduced, the threshold flux, which defines the maximum permeate flow rate characterized by a low constant fouling rate regime. This concept, more than the critical flux, is a new practical tool for membrane process designers. In this paper a brief review on critical and threshold flux will be reported and analyzed. And since the concepts share many common aspects, merged into a new concept, called the boundary flux, the validation will occur by the analysis of previously collected data by the authors, during the treatment of olive vegetation wastewater by ultrafiltration and nanofiltration membranes.

  9. Modelling weed emergence patterns

    NARCIS (Netherlands)

    Vleeshouwers, L.M.


    Anticipating weed pressure may be important in selecting and timing weed control measures in order to optimize their effectiveness, and thus reduce herbicide use. Therefore, a predictive model of the time of emergence and the numbers of seedling emerging (the weed emergence pattern) after

  10. Emerging technology and ethics

    CERN Document Server

    Wakunuma, Kutoma


    This e-book on Emerging Technologies and Ethics includes a collection of essays which explore the future and ethics of emerging information and communication technologies. Articles in the collection include an overview of the legal implications which may be relevant to the ethical aspects of emerging technologies and also ethical issues arising from the mass-take up of mobile technologies.

  11. Determination of surface fluxes using a Bowen ratio system | Kakane ...

    African Journals Online (AJOL)

    Components of the surface fluxes of the energy balance equation were determined using a Campbell Bowen ratio system. ... Soil heat flux (Qg) was measured with ground heat flux plates and the change in energy storage of the layer of soil above the heat flux plates was computed using direct measurements of soil ...

  12. Neutron-diffraction investigations of flux-lines in superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Forgan, E.M. [Birmingham Univ. (United Kingdom); Lee, S.L. [Saint Andrews Univ. (United Kingdom); McKPaul, D. [Warwick Univ., Coventry (United Kingdom); Mook, H.A. [Oak Ridge National Lab., TN (United States); Cubitt, R. [Institut Max von Laue - Paul Langevin (ILL), 38 - Grenoble (France)


    SANS has proved an extremely useful tool for investigating flux-line structures within the bulk of superconductors. With high-T{sub c} materials, the scattered intensities are weak, but careful measurements are giving important new information about flux lattices, flux pinning and flux-lattice melting. (author). 10 refs.

  13. Eddy covariance based methane flux in Sundarbans mangroves, India

    Indian Academy of Sciences (India)

    Eddy covariance based methane flux in Sundarbans mangroves, India ... Eddy covariance; mangrove forests; methane flux; Sundarbans. ... In order to quantify the methane flux in mangroves, an eddy covariance flux tower was recently erected in the largest unpolluted and undisturbed mangrove ecosystem in Sundarbans ...

  14. Generating energy dependent neutron flux maps for effective ...

    African Journals Online (AJOL)

    For activation analysis and irradiation scheme of miniature neutron source reactor, designers or engineers usually require information on thermal neutron flux levels and other energy group flux levels (such as fast, resonance and epithermal). A methodology for readily generating such flux maps and flux profiles for any ...

  15. Standardized Automated CO2/H2O Flux Systems for Individual Research Groups and Flux Networks (United States)

    Burba, George; Begashaw, Israel; Fratini, Gerardo; Griessbaum, Frank; Kathilankal, James; Xu, Liukang; Franz, Daniela; Joseph, Everette; Larmanou, Eric; Miller, Scott; Papale, Dario; Sabbatini, Simone; Sachs, Torsten; Sakai, Ricardo; McDermitt, Dayle


    In recent years, spatial and temporal flux data coverage improved significantly, and on multiple scales, from a single station to continental networks, due to standardization, automation, and management of data collection, and better handling of the extensive amounts of generated data. With more stations and networks, larger data flows from each station, and smaller operating budgets, modern tools are required to effectively and efficiently handle the entire process. Such tools are needed to maximize time dedicated to authoring publications and answering research questions, and to minimize time and expenses spent on data acquisition, processing, and quality control. Thus, these tools should produce standardized verifiable datasets and provide a way to cross-share the standardized data with external collaborators to leverage available funding, promote data analyses and publications. LI-COR gas analyzers are widely used in past and present flux networks such as AmeriFlux, ICOS, AsiaFlux, OzFlux, NEON, CarboEurope, and FluxNet-Canada, etc. These analyzers have gone through several major improvements over the past 30 years. However, in 2016, a three-prong development was completed to create an automated flux system which can accept multiple sonic anemometer and datalogger models, compute final and complete fluxes on-site, merge final fluxes with supporting weather soil and radiation data, monitor station outputs and send automated alerts to researchers, and allow secure sharing and cross-sharing of the station and data access. Two types of these research systems were developed: open-path (LI-7500RS) and enclosed-path (LI-7200RS). Key developments included: • Improvement of gas analyzer performance • Standardization and automation of final flux calculations onsite, and in real-time • Seamless integration with latest site management and data sharing tools In terms of the gas analyzer performance, the RS analyzers are based on established LI-7500/A and LI-7200

  16. Molten Metal Treatment by Salt Fluxing with Low Environmental Emissions

    Energy Technology Data Exchange (ETDEWEB)

    Yogeshwar Sahai


    Abstract: Chlorine gas is traditionally used for fluxing of aluminum melt for removal of alkali and alkaline earth elements. However this results in undesirable emissions of particulate matter and gases such as HCl and chlorine, which are often at unacceptable levels. Additionally, chlorine gas is highly toxic and its handling, storage, and use pose risks to employees and the local community. Holding of even minimal amounts of chlorine necessitates extensive training for all plant employees. Fugitive emissions from chlorine usage within the plant cause accelerated corrosion of plant equipment. The Secondary Aluminum Maximum Achievable Control Technology (MACT) under the Clean Air Act, finalized in March 2000 has set very tough new limits on particulate matter (PM) and total hydrogen chloride emissions from aluminum melting and holding furnaces. These limits are 0.4 and 0.1 lbs per ton of aluminum for hydrogen chloride and particulate emissions, respectively. Assuming new technologies for meeting these limits can be found, additional requirements under the Clean Air Act (Prevention of Significant Deterioration and New Source Review) trigger Best Available Control Technology (BACT) for new sources with annual emissions (net emissions not expressed per ton of production) over specified amounts. BACT currently is lime coated bag-houses for control of particulate and HCl emissions. These controls are expensive, difficult to operate and maintain, and result in reduced American competitiveness in the global economy. Solid salt fluxing is emerging as a viable option for the replacement of chlorine gas fluxing, provided emissions can be consistently maintained below the required levels. This project was a cooperative effort between the Ohio State University and Alcoa to investigate and optimize the effects of solid chloride flux addition in molten metal for alkali impurity and non-metallic inclusion removal minimizing dust and toxic emissions and maximizing energy

  17. Magnetic flux expulsions and secular acceleration pulses at the core surface: is there a link? (Invited) (United States)

    Chulliat, A.


    Recent observational studies based upon satellite data have shown that magnetic flux is being expelled from the core in several regions of the core surface. This phenomenon is observed below the South Atlantic Anomaly, where at least two reversed flux patches have been growing for several decades, including one under St Helena Island, and below the North polar region, where a small reversed flux patch has emerged in the 1990s, contributing to the acceleration of the North magnetic pole over the same time interval. Secular acceleration pulses are rapid surges in the second order derivative of the radial magnetic field at the core surface. The most recent pulse occurred in 2005 and was at the origin of the 2003 and 2007 geomagnetic jerks, defined as sudden changes in the field second derivative at the Earth’s surface. It was largest under St Helena and Cocos Islands. The simultaneous occurrences in the 2000s of a flux expulsion and an acceleration pulse under the St Helena region are intriguing. Both phenomena were also simultaneously observed under the North polar region in the 1990s. This presentation will (a) briefly review recent evidence in favor of the existence of magnetic flux expulsions and secular acceleration pulses at the core surface, and (b) discuss possible kinematic and dynamical links between both phenomena.

  18. Freezing E3-brane instantons with fluxes

    CERN Document Server

    Bianchi, Massimo; Martucci, Luca


    E3-instantons that generate non-perturbative superpotentials in IIB N=1 compactifications are more frequent than currently believed. Worldvolume fluxes will typically lift the E3-brane geometric moduli and their fermionic superpartners, leaving only the two required universal fermionic zero-modes. We consistently incorporate SL(2, Z) monodromies and world-volume fluxes in the effective theory of the E3-brane fermions and study the resulting zero-mode spectrum, highlighting the relation between F-theory and perturbative IIB results. This leads us to a IIB derivation of the index for generation of superpotential terms, which reproduces and generalizes available results. Furthermore, we show how worldvolume fluxes can be explicitly constructed in a one-modulus compactification, such that an E3-instanton has exactly two fermonic zero-modes. This construction is readily applicable to numerous scenarios.

  19. CO2 fluxes near a forest edge

    DEFF Research Database (Denmark)

    Sogachev, Andrey; Leclerc, Monique Y.; Zhang, Gensheng


    In contrast with recent advances on the dynamics of the flow at a forest edge, few studies have considered its role on scalar transport and, in particular, on CO2 transfer. The present study addresses the influence of the abrupt roughness change on forest atmosphere CO2 exchange and contrasts...... the concentration and flux fields against those of a uniform forested surface. We use an atmospheric boundary layer two-equation closure model that accounts for the flow dynamics and vertical divergence of CO2 sources/sinks within a plant canopy. This paper characterizes the spatial variation of CO2 fluxes...... as a function of both sources/sinks distribution and the vertical structure of the canopy. Results suggest that the ground source plays a major role in the formation of wave-like vertical CO2 flux behavior downwind of a forest edge, despite the fact that the contribution of foliage sources/sinks changes...

  20. Comic ray flux anisotropies caused by astrospheres (United States)

    Scherer, K.; Strauss, R. D.; Ferreira, S. E. S.; Fichtner, H.


    Huge astrospheres or stellar wind bubbles influence the propagation of cosmic rays at energies up to the TeV range and can act as small-scale sinks decreasing the cosmic ray flux. We model such a sink (in 2D) by a sphere of radius 10 pc embedded within a sphere of a radius of 1 kpc. The cosmic ray flux is calculated by means of backward stochastic differential equations from an observer, which is located at r0, to the outer boundary. It turns out that such small-scale sinks can influence the cosmic ray flux at the observer's location by a few permille (i.e. a few 0.1%), which is in the range of the observations by IceCube, Milagro and other large area telescopes.

  1. Warped Kähler potentials and fluxes

    Energy Technology Data Exchange (ETDEWEB)

    Martucci, Luca [Dipartimento di Fisica ed Astronomia “Galileo Galilei' ,Università di Padova & I.N.F.N. Sezione di Padova,Via Marzolo 8, 35131 Padova (Italy)


    The four-dimensional effective theory for type IIB warped flux compactifications proposed in is completed by taking into account the backreaction of the Kähler moduli on the three-form fluxes. The only required modification consists in a flux-dependent contribution to the chiral fields parametrising the Kähler moduli. The resulting supersymmetric effective theory satisfies the no-scale condition and consistently combines previous partial results present in the literature. Similar results hold for M-theory warped compactifications on Calabi-Yau fourfolds, whose effective field theory and Kähler potential are also discussed.

  2. Internal analysis of a transverse flux sensor (United States)

    Voyant, J.-Yves; Yonnet, J.-Paul; Jay, Guillaume; Foucher, Christian


    Rotary variable differential transformer (RVDT) sensors are used for industrial applications and are appreciated for their frictionless operation, reliability, linearity and sensitivity. The sensor shown here derives from a classic RVDT and is based on a differential rotating transformer. The functioning principle is explained and experimental measurements are shown. The originality of the studied sensor lies in the transverse flux design which gives a linearity error less than 0.1% of the stroke. However, this transverse flux circulation has uncommon features for an electrotechnical system due to flux paths which are not enclosed in radial planes. Finite element and experimental analysis are used for the magnetic study. This study aims to enhance sensor performances and manufacturing easiness.

  3. Planck intermediate results - LII. Planet flux densities

    DEFF Research Database (Denmark)

    Akrami, Y.; Ashdown, M.; Aumont, J.


    Measurements of flux density are described for five planets, Mars, Jupiter, Saturn, Uranus, and Neptune, across the six Planck High Frequency Instrument frequency bands (100–857 GHz) and these are then compared with models and existing data. In our analysis, we have also included estimates...... of the brightness of Jupiter and Saturn at the three frequencies of the Planck Low Frequency Instrument (30, 44, and 70 GHz). The results provide constraints on the intrinsic brightness and the brightness time-variability of these planets. The majority of the planet flux density estimates are limited by systematic...... errors, but still yield better than 1% measurements in many cases. Applying data from Planck HFI, the Wilkinson Microwave Anisotropy Probe (WMAP), and the Atacama Cosmology Telescope (ACT) to a model that incorporates contributions from Saturn’s rings to the planet’s total flux density suggests a best...

  4. Heat-Flux Gage thermophosphor system

    Energy Technology Data Exchange (ETDEWEB)

    Tobin, K.W.


    This document describes the installation, hardware requirements, and application of the Heat-Flux Gage (Version 1.0) software package developed by the Oak Ridge National Laboratory, Applied Technology Division. The developed software is a single component of a thermographic phosphor-based temperature and heat-flux measurement system. The heat-flux transducer was developed by EG G Energy Measurements Systems and consists of a 1- by 1-in. polymethylpentene sheet coated on the front and back with a repeating thermographic phosphor pattern. The phosphor chosen for this application is gadolinium oxysulphide doped with terbium. This compound has a sensitive temperature response from 10 to 65.6{degree}C (50--150{degree}F) for the 415- and 490-nm spectral emission lines. 3 refs., 17 figs.

  5. Regulation of Na+ fluxes in plants

    Directory of Open Access Journals (Sweden)

    Frans eMaathuis


    Full Text Available When exposed to salt, every plant takes up Na+ from the environment. Once in the symplast, Na+ is distributed within cells and between different tissues and organs. There it can help to lower the cellular water potential but also exert potentially toxic effects. Control of Na+ fluxes is therefore crucial and indeed, research shows that the divergence between salt tolerant and salt sensitive plants is not due to a variation in transporter types but rather originates in the control of uptake and internal Na+ fluxes. A number of regulatory mechanisms has been identified based on signalling of Ca2+, cyclic nucleotides, reactive oxygen species, hormones, or on transcriptional and post translational changes of gene and protein expression. This review will give an overview of intra- and intercellular movement of Na+ in plants and will summarise our current ideas of how these fluxes are controlled and regulated in the early stages of salt stress.

  6. Evaluating Energy Flux in Vibrofluidized Granular Bed

    Directory of Open Access Journals (Sweden)

    N. A. Sheikh


    Full Text Available Granular flows require sustained input of energy for fluidization. A level of fluidization depends on the amount of heat flux provided to the flow. In general, the dissipation of the grains upon interaction balances the heat inputs and the resultant flow patterns can be described using hydrodynamic models. However, with the increase in packing fraction, the heat fluxes prediction of the cell increases. Here, a comparison is made for the proposed theoretical models against the MD simulations data. It is observed that the variation of packing fraction in the granular cell influences the heat flux at the base. For the elastic grain-base interaction, the predictions vary appreciably compared to MD simulations, suggesting the need to accurately model the velocity distribution of grains for averaging.

  7. Flux Analysis in Process Models via Causality

    Directory of Open Access Journals (Sweden)

    Ozan Kahramanoğulları


    Full Text Available We present an approach for flux analysis in process algebra models of biological systems. We perceive flux as the flow of resources in stochastic simulations. We resort to an established correspondence between event structures, a broadly recognised model of concurrency, and state transitions of process models, seen as Petri nets. We show that we can this way extract the causal resource dependencies in simulations between individual state transitions as partial orders of events. We propose transformations on the partial orders that provide means for further analysis, and introduce a software tool, which implements these ideas. By means of an example of a published model of the Rho GTP-binding proteins, we argue that this approach can provide the substitute for flux analysis techniques on ordinary differential equation models within the stochastic setting of process algebras.

  8. Real Time Flux Control in PM Motors

    Energy Technology Data Exchange (ETDEWEB)

    Otaduy, P.J.


    Significant research at the Oak Ridge National Laboratory (ORNL) Power Electronics and Electric Machinery Research Center (PEEMRC) is being conducted to develop ways to increase (1) torque, (2) speed range, and (3) efficiency of traction electric motors for hybrid electric vehicles (HEV) within existing current and voltage bounds. Current is limited by the inverter semiconductor devices' capability and voltage is limited by the stator wire insulation's ability to withstand the maximum back-electromotive force (emf), which occurs at the upper end of the speed range. One research track has been to explore ways to control the path and magnitude of magnetic flux while the motor is operating. The phrase, real time flux control (RTFC), refers to this mode of operation in which system parameters are changed while the motor is operating to improve its performance and speed range. RTFC has potential to meet an increased torque demand by introducing additional flux through the main air gap from an external source. It can augment the speed range by diverting flux away from the main air gap to reduce back-emf at high speeds. Conventional RTFC technology is known as vector control [1]. Vector control decomposes the stator current into two components; one that produces torque and a second that opposes (weakens) the magnetic field generated by the rotor, thereby requiring more overall stator current and reducing the efficiency. Efficiency can be improved by selecting a RTFC method that reduces the back-emf without increasing the average current. This favors methods that use pulse currents or very low currents to achieve field weakening. Foremost in ORNL's effort to develop flux control is the work of J. S. Hsu. Early research [2,3] introduced direct control of air-gap flux in permanent magnet (PM) machines and demonstrated it with a flux-controlled generator. The configuration eliminates the problem of demagnetization because it diverts all the flux from the

  9. From Hubble's NGSL to Absolute Fluxes (United States)

    Heap, Sara R.; Lindler, Don


    Hubble's Next Generation Spectral Library (NGSL) consists of R-l000 spectra of 374 stars of assorted temperature, gravity, and metallicity. Each spectrum covers the wavelength range, 0.18-1.00 microns. The library can be viewed and/or downloaded from the website, Stars in the NGSL are now being used as absolute flux standards at ground-based observatories. However, the uncertainty in the absolute flux is about 2%, which does not meet the requirements of dark-energy surveys. We are therefore developing an observing procedure that should yield fluxes with uncertainties less than 1 % and will take part in an HST proposal to observe up to 15 stars using this new procedure.

  10. Eddy Correlation Flux Measurement System Handbook

    Energy Technology Data Exchange (ETDEWEB)

    Cook, D. R. [Argonne National Lab. (ANL), Argonne, IL (United States)


    The eddy correlation (ECOR) flux measurement system provides in situ, half-hour measurements of the surface turbulent fluxes of momentum, sensible heat, latent heat, and carbon dioxide (CO2) (and methane at one Southern Great Plains extended facility (SGP EF) and the North Slope of Alaska Central Facility (NSA CF). The fluxes are obtained with the eddy covariance technique, which involves correlation of the vertical wind component with the horizontal wind component, the air temperature, the water vapor density, and the CO2 concentration. The instruments used are: • a fast-response, three-dimensional (3D) wind sensor (sonic anemometer) to obtain the orthogonal wind components and the speed of sound (SOS) (used to derive the air temperature) • an open-path infrared gas analyzer (IRGA) to obtain the water vapor density and the CO2 concentration, and • an open-path infrared gas analyzer (IRGA) to obtain methane density and methane flux at one SGP EF and at the NSA CF. The ECOR systems are deployed at the locations where other methods for surface flux measurements (e.g., energy balance Bowen ratio [EBBR] systems) are difficult to employ, primarily at the north edge of a field of crops. A Surface Energy Balance System (SEBS) has been installed collocated with each deployed ECOR system in SGP, NSA, Tropical Western Pacific (TWP), ARM Mobile Facility 1 (AMF1), and ARM Mobile Facility 2 (AMF2). The surface energy balance system consists of upwelling and downwelling solar and infrared radiometers within one net radiometer, a wetness sensor, and soil measurements. The SEBS measurements allow the comparison of ECOR sensible and latent heat fluxes with the energy balance determined from the SEBS and provide information on wetting of the sensors for data quality purposes. The SEBS at one SGP and one NSA site also support upwelling and downwelling PAR measurements to qualify those two locations as Ameriflux sites.

  11. Cotunneling in pairs of coupled flux qubits (United States)

    Lanting, T.; Harris, R.; Johansson, J.; Amin, M. H. S.; Berkley, A. J.; Gildert, S.; Johnson, M. W.; Bunyk, P.; Tolkacheva, E.; Ladizinsky, E.; Ladizinsky, N.; Oh, T.; Perminov, I.; Chapple, E. M.; Enderud, C.; Rich, C.; Wilson, B.; Thom, M. C.; Uchaikin, S.; Rose, G.


    We report measurements of macroscopic resonant tunneling between the two lowest energy states of a pair of magnetically coupled rf-superconducting quantum interference device flux qubits. This technique provides both a direct means of measuring the energy gap of the two-qubit system and a method for probing of the environment coupled to the pair of qubits. Measurements of the tunneling rate as a function of qubit flux bias show a Gaussian line shape that is well matched to theoretical predictions. Moreover, the peak widths indicate that each qubit is coupled to a local environment whose fluctuations are uncorrelated with that of the other qubit.

  12. High-flux cellulose acetate membranes

    Energy Technology Data Exchange (ETDEWEB)

    Boeddeker, K.W.; Finken, H.; Wenzlaff, A.


    Three routes to increase the permeate flux of asymmetric cellulose diacetate membranes of the Loeb-Sourirajan type are investigated: increasing the hydrophilicity of the membranes; increasing their compaction stability; employing a swelling agent which allows for higher solvent-to-polymer ratio in the casting solution. The effect of casting solution composition on flux and rejection of formamide-modified cellulose acetate membranes is shown in Figure 1, illustrating the general capability of this membrane type as function of solvent concentration. Membranes of casting solution composition cellulose diacetate/acetone/formamide 23/52/25 (solvent-to-polymer ratio 2.26) were used as reference membranes in this work.

  13. High-flux cellulose acetate membranes

    Energy Technology Data Exchange (ETDEWEB)

    Boeddeker, K.W.; Finken, H.; Wenzlaff, A.


    Three routes to increase the permeate flux of asymmetric cellulose diacetate membranes of the Loeb-Sourirajan type were investigated: increasing the hydrophilicity of the membranes; increasing their compaction stability, and employing a swelling agent which allows for higher solvent-to-polymer ratio in the casting solution. The effect of casting solution composition on flux and rejection of formamide-modified cellulose acetate membrane is included, illustrating the general capability of this membrane type as function of solvent concentration. Membranes of casting solution composition cellulose diacetate/acetone/formamide 23/52/25 were used as reference membranes in the work. 6 figures. (DP)

  14. Measuring the Magnetic Flux Density with Flux Loops and Hall Probes in the CMS Magnet Flux Return Yoke

    CERN Document Server

    Curé, B; Ball, A; Gaddi, A; Gerwig, H; Hervé, A; Klyukhin, V I; Loveless, R; Mulders, M


    The Compact Muon Solenoid (CMS) is a general purpose detector, designed to run at the highest luminosity at the CERN Large Hadron Collider (LHC). Its distinctive features include a 4 T superconducting solenoid with 6-m-diameter by 12.5-m-length free bore, enclosed inside a 10,000-ton return yoke made of construction steel. The flux return yoke consists of five dodecagonal three-layered barrel wheels and four end-cap disks at each end comprised of steel blocks up to 620 mm thick, which serve as the absorber plates of the muon detection system. To measure the field in and around the steel, a system of 22 flux loops and 82 3-D Hall sensors is installed on the return yoke blocks. A TOSCA 3-D model of the CMS magnet is developed to describe the magnetic field everywhere outside the tracking volume that was measured with the field-mapping machine. The voltages induced in the flux loops by the magnetic flux changing during the CMS magnet standard ramps down are measured with six 16-bit DAQ modules. The off-line inte...

  15. Eddy covariance flux measurements of ozone: Three stations side-by-side (United States)

    Song, G.; Voß, L.; Falge, E.; Mayer, J.-C.; Moravek, A.; Trebs, I.; Bruse, M.; Zhu, Z.; Andreae, M. O.; Meixner, F. X.


    Since about two decades, fast response ozone analyzers, based on gas-phase chemiluminescence ("Güsten type"), became more and more available and emerged to be operational in atmosphere-biosphere exchange studies using the eddy-covariance technique. While there are first preliminary reports about measurements of the vertical profile of ozone fluxes in forest canopies (addressing the question of vertical flux divergence), measurements by ozone flux stations distributed in a horizontally arranged array (addressing questions of horizontal divergence and/or footprint) might be feasible. For all these measurements, the precision of ozone flux stations is of particular interest, because it defines the vertical/horizontal resolution of expected flux divergence. As a first step in this direction, we performed a 9 week, side-by-side experiment of three ozone flux stations on a small airfield in Mainz-Finthen/Germany (49.969° N, 8.148° E, 227 m a.s.l.) in late summer/autumn 2011. Turbulent fluctuations of ozone concentration (in arbitrary units) have been measured by three identical gas-phase chemiluminescence anaylzers (enviscope GmbH/ Germany) with a sampling frequency of 20 Hz. Absolute ozone concentrations have been monitored by three slow-response UV-absorption based analyzers (model 205, 2BTechnologies/U.S.A.; model 49i, ThermoInstruments/U.S.A.) every 2 and 10 seconds, respectively. Three 3D sonic anemometers (model USA-1, METEK/Germany; model CSAT3, Campbell Scientific/U.K.) have been applied to obtain fluctuations of 3D wind vectors and temperature (20Hz). All fast response sensors were mounted at 3 m above ground, the three flux stations have been aligned in cross-wind direction in a distance of about 5.5 m to each other. Sensor separation (3D anemometer - ozone intake) was 0.3 m, the length of ozone intake tubes were about 3 m. Ozone monitors have routinely been calibrated every 15 days. For the calculation of turbulent fluxes of ozone, momentum, and sensible

  16. Limit on the diffuse flux of ultrahigh energy tau neutrinos with the surface detector of the Pierre Auger Observatory

    NARCIS (Netherlands)

    Abraham, J.; Abreu, P.; Aglietta, M.; Aguirre, C.; Ahn, E. J.; Allard, D.; Allekotte, I.; Allen, J.; Allison, P.; Alvarez-Muniz, J.; Ambrosio, M.; Anchordoqui, L.; Andringa, S.; Anzalone, A.; Aramo, C.; Argiro, S.; Arisaka, K.; Arneodo, F.; Arqueros, F.; Asch, T.; Asorey, H.; Assis, P.; Aublin, J.; Ave, M.; Avila, G.; Baecker, T.; Badagnani, D.; Barber, K. B.; Barbosa, A. F.; Barroso, S. L. C.; Baughman, B.; Bauleo, P.; Beatty, J. J.; Beau, T.; Becker, B. R.; Becker, K. H.; Belletoile, A.; Bellido, J. A.; BenZvi, S.; Berat, C.; Bernardini, P.; Bertou, X.; Biermann, P. L.; Billoir, P.; Blanch-Bigas, O.; Blanco, F.; Bleve, C.; Bluemer, H.; Bohacova, M.; Bonifazi, C.; Bonino, R.; Brack, J.; Brogueira, P.; Brown, W. C.; Bruijn, R.; Buchholz, P.; Bueno, A.; Burton, R. E.; Busca, N. G.; Caballero-Mora, K. S.; Caramete, L.; Caruso, R.; Carvalho, W.; Castellina, A.; Catalano, O.; Cazon, L.; Cester, R.; Chauvin, J.; Chiavassa, A.; Chinellato, J. A.; Chou, A.; Chudoba, J.; Chye, J.; Clay, R. W.; Colombo, E.; Conceicao, R.; Connolly, B.; Contreras, F.; Coppens, J.; Cordier, A.; Cotti, U.; Coutu, S.; Covault, C. E.; Creusot, A.; Criss, A.; Cronin, J.; Curutiu, A.; Dagoret-Campagne, S.; Daumiller, K.; Dawson, B. R.; de Almeida, R. M.; De Domenico, M.; De Donato, C.; de Jong, S. J.; De La Vega, G.; de Mello, W. J. M.; de Mello Neto, J. R. T.; De Mitri, I.; de Souza, V.; Decerprit, G.; del Peral, L.; Deligny, O.; Della Selva, A.; Delle Fratte, C.; Dembinski, H.; Di Giulio, C.; Diaz, J. C.; Diep, P. N.; Dobrigkeit, C.; D'Olivo, J. C.; Dong, P. N.; Dornic, D.; Dorofeev, A.; dos Anjos, J. C.; Dova, M. T.; D'Urso, D.; Dutan, I.; DuVernois, M. A.; Engel, R.; Escobar, C. O.; Etchegoyen, A.; San Luis, P. Facal; Falcke, H.; Farrar, G.; Fauth, A. C.; Fazzini, N.; Ferrer, F.; Ferrero, A.; Fick, B.; Filevich, A.; Filipcic, A.; Fleck, I.; Fliescher, S.; Fracchiolla, C. E.; Fraenkel, E. D.; Fulgione, W.; Gamarra, R. F.; Gambetta, S.; Garcia, B.; Garcia Gamez, D.; Garcia-Pinto, D.; Garrido, X.; Gelmini, G.; Gemmeke, H.; Ghia, P. L.; Giaccari, U.; Giller, M.; Glass, H.; Goggin, L. M.; Gold, M. S.; Golup, G.; Gomez Albarracin, F.; Gomez Berisso, M.; Goncalves, P.; do Amaral, M. Goncalves; Gonzalez, D.; Gonzalez, J. G.; Gora, D.; Gorgi, A.; Gouffon, P.; Grebe, S.; Grigat, M.; Grillo, A. F.; Guardincerri, Y.; Guarino, F.; Guedes, G. P.; Gutierrez, J.; Hague, J. D.; Halenka, V.; Hansen, P.; Harari, D.; Harmsma, S.; Harton, J. L.; Haungs, A.; Healy, M. D.; Hebbeker, T.; Hebrero, G.; Heck, D.; Hojvat, C.; Holmes, V. C.; Homola, P.; Hoerandel, J. R.; Horneffer, A.; Hrabovsky, M.; Huege, T.; Hussain, M.; Iarlori, M.; Insolia, A.; Ionita, F.; Italiano, A.; Jiraskova, S.; Kaducak, M.; Kampert, K. H.; Karova, T.; Kasper, P.; Kegl, B.; Keilhauer, B.; Kemp, E.; Kieckhafer, R. M.; Klages, H. O.; Kleifges, M.; Kleinfeller, J.; Knapik, R.; Knapp, J.; Koang, D. -H.; Krieger, A.; Kroemer, O.; Kruppke, D.; Kuempel, D.; Kunka, N.; Kusenko, A.; La Rosa, G.; Lachaud, C.; Lago, B. L.; Leao, M. S. A. B.; Lebrun, D.; Lebrun, P.; Lee, J.; Leigui de Oliveira, M. A.; Lemiere, A.; Letessier-Selvon, A.; Leuthold, M.; Lhenry-Yvon, I.; Lopez, R.; Lopez Agueera, A.; Lozano Bahilo, J.; Lucero, A.; Luna Garcia, R.; Maccarone, M. C.; Macolino, C.; Maldera, S.; Mandat, D.; Mantsch, P.; Mariazzi, A. G.; Maris, I. C.; Marquez Falcon, H. R.; Martello, D.; Martinez, J.; Martinez Bravo, O.; Mathes, H. J.; Matthews, J.; Matthews, J. A. J.; Matthiae, G.; Maurizio, D.; Mazur, P. O.; McEwen, M.; McNeil, R. R.; Medina-Tanco, G.; Melissas, M.; Melo, D.; Menichetti, E.; Menshikov, A.; Meyhandan, R.; Micheletti, M. I.; Miele, G.; Miller, W.; Miramonti, L.; Mollerach, S.; Monasor, M.; Ragaigne, D. Monnier; Montanet, F.; Morales, B.; Morello, C.; Moreno, J. C.; Morris, C.; Mostafa, M.; Mueller, S.; Muller, M. A.; Mussa, R.; Navarra, G.; Navarro, J. L.; Navas, S.; Necesal, P.; Nellen, L.; Newman-Holmes, C.; Newton, D.; Nhung, P. T.; Nierstenhoefer, N.; Nitz, D.; Nosek, D.; Nozka, L.; Oehlschlaeger, J.; Olinto, A.; Olmos-Gilbaja, V. M.; Ortiz, M.; Ortolani, F.; Pacheco, N.; Selmi-Dei, D. Pakk; Palatka, M.; Pallotta, J.; Parente, G.; Parizot, E.; Parlati, S.; Pastor, S.; Patel, M.; Paul, T.; Pavlidou, V.; Payet, K.; Pech, M.; Pekala, J.; Pelayo, R.; Pepe, I. M.; Perrone, L.; Pesce, R.; Petermann, E.; Petrera, S.; Petrinca, P.; Petrolini, A.; Petrov, Y.; Petrovic, J.; Pfendner, C.; Pichel, A.; Piegaia, R.; Pierog, T.; Pimenta, M.; Pinto, T.; Pirronello, V.; Pisanti, O.; Platino, M.; Pochon, J.; Ponce, V. H.; Pontz, M.; Privitera, P.; Prouza, M.; Quel, E. J.; Rautenberg, J.; Ravignani, D.; Redondo, A.; Reucroft, S.; Revenu, B.; Rezende, F. A. S.; Ridky, J.; Riggi, S.; Risse, M.; Riviere, C.; Rizi, V.; Robledo, C.; Rodriguez, G.; Martino, J. Rodriguez; Rodriguez Rojo, J.; Rodriguez-Cabo, I.; Rodriguez-Frias, M. D.; Ros, G.; Rosado, J.; Roth, M.; Rouille-d'Orfeuil, B.; Roulet, E.; Rovero, A. C.; Salamida, F.; Salazar, H.; Salina, G.; Sanchez, F.; Santander, M.; Santo, C. E.; Santos, E. M.; Sarazin, F.; Sarkar, S.; Sato, R.; Scharf, N.; Scherini, V.; Schieler, H.; Schiffer, P.; Schmidt, A.; Schmidt, F.; Schmidt, T.; Scholten, O.; Schoorlemmer, H.; Schovancova, J.; Schovanek, P.; Schroeder, F.; Schulte, S.; Schuessler, F.; Schuster, D.; Sciutto, S. J.; Scuderi, M.; Segreto, A.; Semikoz, D.; Settimo, M.; Shellard, R. C.; Sidelnik, I.; Siffert, B. B.; Smetniansky De Grande, N.; Smialkowski, A.; Smida, R.; Smith, B. E.; Snow, G. R.; Sommers, P.; Sorokin, J.; Spinka, H.; Squartini, R.; Strazzeri, E.; Stutz, A.; Suarez, F.; Suomijaervi, T.; Supanitsky, A. D.; Sutherland, M. S.; Swain, J.; Szadkowski, Z.; Tamashiro, A.; Tamburro, A.; Tarutina, T.; Tascau, O.; Tcaciuc, R.; Tcherniakhovski, D.; Thao, N. T.; Thomas, D.; Ticona, R.; Tiffenberg, J.; Timmermans, C.; Tkaczyk, W.; Peixoto, C. J. Todero; Tome, B.; Tonachini, A.; Torres, I.; Travnicek, P.; Tridapalli, D. B.; Tristram, G.; Trovato, E.; Tuci, V.; Tueros, M.; Ulrich, R.; Unger, M.; Urban, M.; Valdes Galicia, J. F.; Valino, I.; Valore, L.; van den Berg, A. M.; van Elewyck, V.; Vazquez, R. A.; Veberic, D.; Velarde, A.; Venters, T.; Verzi, V.; Videla, M.; Villasenor, L.; Vorobiov, S.; Voyvodic, L.; Wahlberg, H.; Wahrlich, P.; Wainberg, O.; Warner, D.; Watson, A. A.; Westerhoff, S.; Whelan, B. J.; Wieczorek, G.; Wiencke, L.; Wilczynska, B.; Wilczynski, H.; Wileman, C.; Winnick, M. G.; Wu, H.; Wundheiler, B.; Younk, P.; Yuan, G.; Zas, E.; Zavrtanik, D.; Zavrtanik, M.; Zaw, I.; Zepeda, A.; Ziolkowski, M.

    Data collected at the Pierre Auger Observatory are used to establish an upper limit on the diffuse flux of tau neutrinos in the cosmic radiation. Earth-skimming nu(tau) may interact in the Earth's crust and produce a tau lepton by means of charged-current interactions. The tau lepton may emerge from

  17. Color on emergency mapping (United States)

    Jiang, Lili; Qi, Qingwen; Zhang, An


    There are so many emergency issues in our daily life. Such as typhoons, tsunamis, earthquake, fires, floods, epidemics, etc. These emergencies made people lose their lives and their belongings. Every day, every hour, even every minute people probably face the emergency, so how to handle it and how to decrease its hurt are the matters people care most. If we can map it exactly before or after the emergencies; it will be helpful to the emergency researchers and people who live in the emergency place. So , through the emergency map, before emergency is occurring we can predict the situation, such as when and where the emergency will be happen; where people can refuge, etc. After disaster, we can also easily assess the lost, discuss the cause and make the lost less. The primary effect of mapping is offering information to the people who care about the emergency and the researcher who want to study it. Mapping allows the viewers to get a spatial sense of hazard. It can also provide the clues to study the relationship of the phenomenon in emergency. Color, as the basic element of the map, it can simplify and clarify the phenomenon. Color can also affects the general perceptibility of the map, and elicits subjective reactions to the map. It is to say, structure, readability, and the reader's psychological reactions can be affected by the use of color.

  18. Train operation in emergencies

    CERN Document Server

    Jia, Limin; Qin, Yong


    This book presents the latest findings on train operation theories and methods in the context of emergencies. It examines and assesses a range of aspects—including the definition of a railway emergency, transport organization modes in emergencies, calculating railway transport capacity in emergencies, line planning in emergencies, train re-pathing in emergencies and train re-scheduling in emergencies—that are urgently needed in the railway transportation field, which faces the serious challenge of dealing with emergencies worldwide. The book highlights the latest research results in an integrated and systematic way, and the methodology presented is oriented on real-world problems, allowing it to be used not only directly in railway operational management, but also as the point of departure for further applications or theoretical research. As such, the book will be of considerable interest to graduate students and researchers in the field of traffic and transportation engineering.>.

  19. Assessment of Spatial Representativeness of Eddy Covariance Flux Data from Flux Tower to Regional Grid

    Directory of Open Access Journals (Sweden)

    Hesong Wang


    Full Text Available Combining flux tower measurements with remote sensing or land surface models is generally regarded as an efficient method to scale up flux data from site to region. However, due to the heterogeneous nature of the vegetated land surface, the changing flux source areas and the mismatching between ground source areas and remote sensing grids, direct use of in-situ flux measurements can lead to major scaling bias if their spatial representativeness is unknown. Here, we calculate and assess the spatial representativeness of 15 flux sites across northern China in two aspects: first, examine how well a tower represents fluxes from the specific targeted vegetation type, which is called vegetation-type level; and, second, examine how representative is the flux tower footprint of the broader landscape or regional extents, which is called spatial-scale level. We select fraction of target vegetation type (FTVT and Normalized Difference Vegetation Index (NDVI as key indicators to calculate the spatial representativeness of 15 EC sites. Then, these sites were ranked into four grades based on FTVT or cluster analysis from high to low in order: (1 homogeneous; (2 representative; (3 acceptable; and (4 disturbed measurements. The results indicate that: (1 Footprint climatology for each site was mainly distributed in an irregular shape, had similar spatial pattern as spatial distribution of prevailing wind direction; (2 At vegetation-type level, the number of homogeneous, representative, acceptable and disturbed measurements is 8, 4, 1 and 2, respectively. The average FTVT was 0.83, grass and crop sites had greater representativeness than forest sites; (3 At spatial-scale level, flux sites with zonal vegetation had greater representativeness than non-zonal vegetation sites, and the scales were further divided into three sub-scales: (a in flux site scale, the average of absolute NDVI bias was 4.34%, the number of the above four grades is 9, 4, 1 and 1, respectively

  20. Integrated passive flux measurement in groundwater: design and performance of iFLUX samplers (United States)

    Verreydt, Goedele; Razaei, Meisam; Meire, Patrick; Van Keer, Ilse; Bronders, Jan; Seuntjens, Piet


    The monitoring and management of soil and groundwater is a challenge. Current methods for the determination of movement or flux of pollution in groundwater use no direct measurements but only simulations based on concentration measurements and Darcy velocity estimations. This entails large uncertainties which cause remediation failures and higher costs for contaminated site owners. On top of that, the lack of useful data makes it difficult to get approval for a risk-based management approach which completely avoids costly remedial actions. The iFLUX technology is a key development of Dr. Goedele Verreydt at the University of Antwerp and VITO. It is supported by the passive flux measurement technology as invented by Prof. Mike Annable and his team at the University of Florida. The iFLUX technology includes an in situ measurement device for capturing dynamic groundwater quality and quantity, the iFLUX sampler, and an associated interpretation and visualization method. The iFLUX sampler is a modular passive sampler that provides simultaneous in situ point determinations of a time-averaged target compound mass flux and water flux. The sampler is typically installed in a monitoring well where it intercepts the groundwater flow and captures the compounds of interest. The sampler consists of permeable cartridges which are each packed with a specific sorbent matrix. The sorbent matrix of the water flux cartridge is impregnated with known amounts of water soluble resident tracers. These tracers are leached from the matrix at rates proportional to the groundwater flux. The measurements of the contaminants and the remaining resident tracer are used to determine groundwater and target compound fluxes. Exposure times range from 1 week to 6 months, depending on the expected concentration and groundwater flow velocity. The iFLUX sampler technology has been validated and tested at several field projects. Currently, 4 cartridges are tested and available: 1 waterflux cartridge to

  1. High heat flux single phase heat exchanger (United States)

    Valenzuela, Javier A.; Izenson, Michael G.


    This paper presents the results obtained to date in a program to develop a high heat flux, single-phase heat exchanger for spacecraft thermal management. The intended application is a net generation interface heat exchanger to couple the crew module water thermal bus to the two-phase ammonia main thermal bus in the Space Station Freedom. The large size of the interface heat exchanger is dictated by the relatively poor water-side heat transfer characteristics. The objective of this program is to develop a single-phase heat transfer approach which can achieve heat fluxes and heat transfer coefficients comparable to those of the evaporation ammonia side. A new heat exchanger concept has been developed to meet these objecties. The main feature of this heat exchanger is that it can achieve very high heat fluxes with a pressure drop one to two orders of magnitude lower than those of previous microchannel or jet impingement high heat flux heat exchangers. This paper describes proof-of-concept experiments performed in air and water and presents analytical model of the heat exchanger.

  2. Demystifying Electric Flux and Gauss's Law (United States)

    McManus, Jeff


    Many physics students have experienced the difficulty of internalizing concepts in electrostatics. After studying concrete, measurable details in mechanics, they are challenged by abstract ideas such as electric fields, flux, Gauss's law, and electric potential. There are a few well-known hands-on activities that help students get experience with…

  3. Exponentially tapered Josephson flux-flow oscillator

    DEFF Research Database (Denmark)

    Benabdallah, A.; Caputo, J. G.; Scott, Alwyn C.


    We introduce an exponentially tapered Josephson flux-flow oscillator that is tuned by applying a bias current to the larger end of the junction. Numerical and analytical studies show that above a threshold level of bias current the static solution becomes unstable and gives rise to a train of flu...

  4. Optimal flux patterns in cellular metabolic networks

    Energy Technology Data Exchange (ETDEWEB)

    Almaas, E


    The availability of whole-cell level metabolic networks of high quality has made it possible to develop a predictive understanding of bacterial metabolism. Using the optimization framework of flux balance analysis, I investigate metabolic response and activity patterns to variations in the availability of nutrient and chemical factors such as oxygen and ammonia by simulating 30,000 random cellular environments. The distribution of reaction fluxes is heavy-tailed for the bacteria H. pylori and E. coli, and the eukaryote S. cerevisiae. While the majority of flux balance investigations have relied on implementations of the simplex method, it is necessary to use interior-point optimization algorithms to adequately characterize the full range of activity patterns on metabolic networks. The interior-point activity pattern is bimodal for E. coli and S. cerevisiae, suggesting that most metabolic reaction are either in frequent use or are rarely active. The trimodal activity pattern of H. pylori indicates that a group of its metabolic reactions (20%) are active in approximately half of the simulated environments. Constructing the high-flux backbone of the network for every environment, there is a clear trend that the more frequently a reaction is active, the more likely it is a part of the backbone. Finally, I briefly discuss the predicted activity patterns of the central-carbon metabolic pathways for the sample of random environments.

  5. On The Vibrational Flux in Bounded Atoms

    CERN Document Server

    Caturello, Naidel A M dos S


    In this paper we derived a model based on general assumptions and allowed us to derive some important thermodynamic functions that are time-dependent, also we could see the behavior of these functions by surfaces. The model is based on independent movements that couple and construct a flux, which makes the system as a whole not to be independent at all.

  6. Predicting flux decline of reverse osmosis membranes

    NARCIS (Netherlands)

    Schippers, J.C.; Hanemaayer, J.H.; Smolders, C.A.; Kostense, A.


    A mathematical model predicting flux decline of reverse osmosis membranes due to colloidal fouling has been verified. This mathema- tical model is based on the theory of cake or gel filtration and the Modified Fouling Index (MFI). Research was conducted using artificial colloidal solutions and a

  7. Diameter effect on critical heat flux

    Energy Technology Data Exchange (ETDEWEB)

    Tanase, A. [University of Ottawa, Department of Mechanical Engineering, Ottawa, ON (Canada)], E-mail:; Cheng, S.C. [University of Ottawa, Department of Mechanical Engineering, Ottawa, ON (Canada); Groeneveld, D.C. [University of Ottawa, Department of Mechanical Engineering, Ottawa, ON (Canada); Chalk River Laboratories, Atomic Energy of Canada Ltd., Chalk River, ON (Canada); Shan, J.Q. [Department of Nuclear Engineering, Xi' an Jiaotong University (China)


    The critical heat flux look-up table (CHF LUT) is widely used to predict CHF for various applications, including design and safety analysis of nuclear reactors. Using the CHF LUT for round tubes having inside diameters different from the reference 8 mm involves conversion of CHF to 8 mm. Different authors [Becker, K.M., 1965. An Analytical and Experimental Study of Burnout Conditions in Vertical Round Ducts, Aktiebolaget Atomenergie Report AE 177, Sweden; Boltenko, E.A., et al., 1989. Effect of tube diameter on CHF at various two phase flow regimes, Report IPE-1989; Biasi, L., Clerici, G.C., Garriba, S., Sala, R., Tozzi, A., 1967. Studies on Burnout, Part 3, Energia Nucleare, vol. 14, pp. 530-536; Groeneveld, D.C., Cheng, S.C., Doan, T., 1986. AECL-UO critical heat flux look-up table. Heat Transfer Eng., 7, 46-62; Groeneveld et al., 1996; Hall, D.D., Mudawar, I., 2000. Critical heat flux for water flow in tubes - II subcooled CHF correlations. Int. J. Heat Mass Transfer, 43, 2605-2640; Wong, W.C., 1996. Effect of tube diameter on critical heat flux, MaSC dissertation, Ottawa Carleton Institute for Mechanical and Aeronautical Engineering, University of Ottawa] have proposed several types of correlations or factors to describe the diameter effect on CHF. The present work describes the derivation of new diameter correction factor and compares it with several existing prediction methods.

  8. High flux expansion divertor studies in NSTX

    Energy Technology Data Exchange (ETDEWEB)

    Soukhanovskii, V A; Maingi, R; Bell, R E; Gates, D A; Kaita, R; Kugel, H W; LeBlanc, B P; Maqueda, R; Menard, J E; Mueller, D; Paul, S F; Raman, R; Roquemore, A L


    Projections for high-performance H-mode scenarios in spherical torus (ST)-based devices assume low electron collisionality for increased efficiency of the neutral beam current drive. At lower collisionality (lower density), the mitigation techniques based on induced divertor volumetric power and momentum losses may not be capable of reducing heat and material erosion to acceptable levels in a compact ST divertor. Divertor geometry can also be used to reduce high peak heat and particle fluxes by flaring a scrape-off layer (SOL) flux tube at the divertor plate, and by optimizing the angle at which the flux tube intersects the divertor plate, or reduce heat flow to the divertor by increasing the length of the flux tube. The recently proposed advanced divertor concepts [1, 2] take advantage of these geometry effects. In a high triangularity ST plasma configuration, the magnetic flux expansion at the divertor strike point (SP) is inherently high, leading to a reduction of heat and particle fluxes and a facilitated access to the outer SP detachment, as has been demonstrated recently in NSTX [3]. The natural synergy of the highly-shaped high-performance ST plasmas with beneficial divertor properties motivated a further systematic study of the high flux expansion divertor. The National Spherical Torus Experiment (NSTX) is a mid-sized device with the aspect ratio A = 1.3-1.5 [4]. In NSTX, the graphite tile divertor has an open horizontal plate geometry. The divertor magnetic configuration geometry was systematically changed in an experiment by either (1) changing the distance between the lower divertor X-point and the divertor plate (X-point height h{sub X}), or by (2) keeping the X-point height constant and increasing the outer SP radius. An initial analysis of the former experiment is presented below. Since in the divertor the poloidal field B{sub {theta}} strength is proportional to h{sub X}, the X-point height variation changed the divertor plasma wetted area due to

  9. Mesoscopic fluctuations in biharmonically driven flux qubits (United States)

    Ferrón, Alejandro; Domínguez, Daniel; Sánchez, María José


    We investigate flux qubits driven by a biharmonic magnetic signal, with a phase lag that acts as an effective time reversal broken parameter. The driving induced transition rate between the ground and the excited state of the flux qubit can be thought of as an effective transmittance, profiting from a direct analogy between interference effects at avoided level crossings and scattering events in disordered electronic systems. For time scales prior to full relaxation, but large compared to the decoherence time, this characteristic rate has been accessed experimentally by Gustavsson et al. [Phys. Rev. Lett. 110, 016603 (2013)], 10.1103/PhysRevLett.110.016603 and its sensitivity with both the phase lag and the dc flux detuning explored. In this way, signatures of universal conductance fluctuationslike effects have been analyzed and compared with predictions from a phenomenological model that only accounts for decoherence, as a classical noise. Here we go beyond the classical noise model and solve the full dynamics of the driven flux qubit in contact with a quantum bath employing the Floquet-Born-Markov master equation. Within this formalism, the computed relaxation and decoherence rates turn out to be strongly dependent on both the phase lag and the dc flux detuning. Consequently, the associated pattern of fluctuations in the characteristic rates display important differences with those obtained within the mentioned phenomenological model. In particular, we demonstrate the weak localizationlike effect in the average values of the relaxation rate. Our predictions can be tested for accessible but longer time scales than the current experimental times.

  10. Electric field control of emergent electrodynamics in quantum spin ice (United States)

    Lantagne-Hurtubise, Étienne; Bhattacharjee, Subhro; Moessner, R.


    We study the coupling between conventional (Maxwell) and emergent electrodynamics in quantum spin ice, a 3+1-dimensional U (1 ) quantum spin liquid. We find that a uniform electric field can be used to tune the properties of both the ground state and excitations of the spin liquid. In particular, it induces emergent birefringence, rendering the speed of the emergent light anisotropic and polarization-dependent. A sufficiently strong electric field triggers a quantum phase transition into new U (1 ) quantum spin liquid phases, which trap emergent electric π fluxes. The flux patterns of these new phases depend on the direction of the electric field. Strikingly, some of the canonical pinch points in the spin structure factor, characteristic of classical spin ice, emerge near the phase transition, while they are absent in the quantum spin liquid phases. Estimating the electric field strength required, we find that this transition is potentially accessible experimentally. Finally, we propose a minimal mechanism by which an oscillating electric field can generate emergent radiation inside a quantum spin ice material with non-Kramers spin doublets.

  11. Energy emergency handbook

    Energy Technology Data Exchange (ETDEWEB)


    This Handbook identifies selected state and federal measures available to mitigate the impact of an energy emergency, and provides a comprehensive energy emergency communications directory. In the case of state remedial actions, particular emphasis has been placed on typical implementation procedures and likely impacts. The discussions of federal actions focus on initation and implementation procedures. The directory is designed to facilitate communications of all types (telephone, Telex, TWX, or facsimile) among key energy emergency officials in the federal and state governments.

  12. Thermodynamics and emergent universe


    Ghosh, Saumya; Gangopadhyay, Sunandan


    We show that in the isentropic scenario the first order thermodynamical particle creation model gives an emergent universe solution even when the chemical potential is non-zero. However there exists no emergent universe scenario in the second order non-equilibrium theory for the particle creation model. We then point out a correspondence between the particle creation model with barotropic equation of state and the equation of state giving rise to an emergent universe without particle creation...

  13. Communication: On the calculation of time-dependent electron flux within the Born-Oppenheimer approximation: A flux-flux reflection principle. (United States)

    Albert, Julian; Hader, Kilian; Engel, Volker


    It is commonly assumed that the time-dependent electron flux calculated within the Born-Oppenheimer (BO) approximation vanishes. This is not necessarily true if the flux is directly determined from the continuity equation obeyed by the electron density. This finding is illustrated for a one-dimensional model of coupled electronic-nuclear dynamics. There, the BO flux is in perfect agreement with the one calculated from a solution of the time-dependent Schrödinger equation for the coupled motion. A reflection principle is derived where the nuclear BO flux is mapped onto the electronic flux.

  14. Tuberculosis in complex emergencies. (United States)

    Coninx, Rudi


    This paper describes the key factors and remaining challenges for tuberculosis (TB) control programmes in complex emergencies. A complex emergency is "a humanitarian crisis in a country, region or society where there is total or considerable breakdown of authority resulting from internal or external conflict and which requires an international response that goes beyond the mandate or capacity of any single agency and/or the ongoing United Nations country programme." Some 200 million people are believed to live in countries affected by complex emergencies; almost all of these are developing countries that also bear the main burden of TB. The effects of complex emergencies impact on TB control programmes, interfering with the goals of identifying and curing TB patients and possibly leading to the emergence of MDR-TB. There are many detailed descriptions of aid interventions during complex emergencies; yet TB control programmes are absent from most of these reports. If TB is neglected, it may quickly result in increased morbidity and mortality, as was demonstrated in Bosnia and Herzegovina and in Somalia. TB is a major disease in complex emergencies and requires an appropriate public health response. While there is no manual to cover complex emergencies, the interagency manual for TB control in refugee and displaced populations provides valuable guidance. These programmes contribute to the body of evidence needed to compile such a manual, and should ensure that the experiences of TB control in complex emergencies lead to the establishment of evidence-based programmes.

  15. Radiological Emergency Response Data (United States)

    U.S. Environmental Protection Agency — Quality Data Asset includes all current and historical emergency radiological response event and incident of national significance data and surveillance, monitoring,...

  16. Emergency care of reptiles. (United States)

    Martinez-Jimenez, David; Hernandez-Divers, Stephen J


    Most reptile emergencies are the result of improper husbandry and nutrition. Reptiles are good at masking disease, and owners, failing to recognize early signs of illness, only seek veterinary assistance when issues are advanced and near terminal. The veterinarian should be familiar with reptile species-specific husbandry and nutritional requirements and basic clinical techniques. The same principles and techniques used in small animal medicine can be applied to reptile emergencies. This article reviews general emergency principles that apply to the reptilian patient and common emergency presentations. The main areas of discussion focus on cardiopulmonary resuscitation, fluid therapy, and analgesia.

  17. EMERGE-ing from the Shadows (United States)

    Grier, Terry B.


    Houston school officials noticed their best performing low-income students weren't applying to Ivy League and selective colleges. In response, they created EMERGE, a program that develops and guides talented youths toward a top-college path.

  18. Formula Expression of Airgap Leakage flux Coefficient of Axial-Flux Permanent Magnet Motor

    Directory of Open Access Journals (Sweden)

    Yanliang Xu


    Full Text Available Airgap leakage flux coefficient is one of the main parameters which must be given ahead of time when performing initial designs or getting performance results by magnetic circuit analysis for any kinds of electrical machines. Three -dimensional finite element method (3D-FEM is the most reliable one to obtain the accurate leakage flux coefficient for axial flux permanent magnet (AFPM motor which definitely takes a much long time and is not advantageous to the motor’s initial and optimal design. By constituting the accurate lumped-parameter magnetic circuit (LPMC model and computing the resultant magnetic reluctances, the analytical formula of the leakage flux coefficient of AFPM is given which is verified by 3D-FEM and the prototyped AFPM experiment.

  19. MetaFluxNet: the management of metabolic reaction information and quantitative metabolic flux analysis. (United States)

    Lee, Dong-Yup; Yun, Hongsoek; Park, Sunwon; Lee, Sang Yup


    MetaFluxNet is a program package for managing information on the metabolic reaction network and for quantitatively analyzing metabolic fluxes in an interactive and customized way. It allows users to interpret and examine metabolic behavior in response to genetic and/or environmental modifications. As a result, quantitative in silico simulations of metabolic pathways can be carried out to understand the metabolic status and to design the metabolic engineering strategies. The main features of the program include a well-developed model construction environment, user-friendly interface for metabolic flux analysis (MFA), comparative MFA of strains having different genotypes under various environmental conditions, and automated pathway layout creation. A manual for MetaFluxNet is available as PDF file.

  20. A Tale of Two Emergences: Sunrise II Observations of Emergence Sites in a Solar Active Region (United States)

    Centeno, R.; Blanco Rodríguez, J.; Del Toro Iniesta, J. C.; Solanki, S. K.; Barthol, P.; Gandorfer, A.; Gizon, L.; Hirzberger, J.; Riethmüller, T. L.; van Noort, M.; Orozco Suárez, D.; Berkefeld, T.; Schmidt, W.; Martínez Pillet, V.; Knölker, M.


    In 2013 June, the two scientific instruments on board the second Sunrise mission witnessed, in detail, a small-scale magnetic flux emergence event as part of the birth of an active region. The Imaging Magnetograph Experiment (IMaX) recorded two small (˜ 5\\prime\\prime ) emerging flux patches in the polarized filtergrams of a photospheric Fe I spectral line. Meanwhile, the Sunrise Filter Imager (SuFI) captured the highly dynamic chromospheric response to the magnetic fields pushing their way through the lower solar atmosphere. The serendipitous capture of this event offers a closer look at the inner workings of active region emergence sites. In particular, it reveals in meticulous detail how the rising magnetic fields interact with the granulation as they push through the Sun’s surface, dragging photospheric plasma in their upward travel. The plasma that is burdening the rising field slides along the field lines, creating fast downflowing channels at the footpoints. The weight of this material anchors this field to the surface at semi-regular spatial intervals, shaping it in an undulatory fashion. Finally, magnetic reconnection enables the field to release itself from its photospheric anchors, allowing it to continue its voyage up to higher layers. This process releases energy that lights up the arch-filament systems and heats the surrounding chromosphere.

  1. Inverse modeling of the terrestrial carbon flux in China with flux covariance among inverted regions (United States)

    Wang, H.; Jiang, F.; Chen, J. M.; Ju, W.; Wang, H.


    Quantitative understanding of the role of ocean and terrestrial biosphere in the global carbon cycle, their response and feedback to climate change is required for the future projection of the global climate. China has the largest amount of anthropogenic CO2 emission, diverse terrestrial ecosystems and an unprecedented rate of urbanization. Thus information on spatial and temporal distributions of the terrestrial carbon flux in China is of great importance in understanding the global carbon cycle. We developed a nested inversion with focus in China. Based on Transcom 22 regions for the globe, we divide China and its neighboring countries into 17 regions, making 39 regions in total for the globe. A Bayesian synthesis inversion is made to estimate the terrestrial carbon flux based on GlobalView CO2 data. In the inversion, GEOS-Chem is used as the transport model to develop the transport matrix. A terrestrial ecosystem model named BEPS is used to produce the prior surface flux to constrain the inversion. However, the sparseness of available observation stations in Asia poses a challenge to the inversion for the 17 small regions. To obtain additional constraint on the inversion, a prior flux covariance matrix is constructed using the BEPS model through analyzing the correlation in the net carbon flux among regions under variable climate conditions. The use of the covariance among different regions in the inversion effectively extends the information content of CO2 observations to more regions. The carbon flux over the 39 land and ocean regions are inverted for the period from 2004 to 2009. In order to investigate the impact of introducing the covariance matrix with non-zero off-diagonal values to the inversion, the inverted terrestrial carbon flux over China is evaluated against ChinaFlux eddy-covariance observations after applying an upscaling methodology.

  2. Flux variability scanning based on enforced objective flux for identifying gene amplification targets (United States)


    Background In order to reduce time and efforts to develop microbial strains with better capability of producing desired bioproducts, genome-scale metabolic simulations have proven useful in identifying gene knockout and amplification targets. Constraints-based flux analysis has successfully been employed for such simulation, but is limited in its ability to properly describe the complex nature of biological systems. Gene knockout simulations are relatively straightforward to implement, simply by constraining the flux values of the target reaction to zero, but the identification of reliable gene amplification targets is rather difficult. Here, we report a new algorithm which incorporates physiological data into a model to improve the model’s prediction capabilities and to capitalize on the relationships between genes and metabolic fluxes. Results We developed an algorithm, flux variability scanning based on enforced objective flux (FVSEOF) with grouping reaction (GR) constraints, in an effort to identify gene amplification targets by considering reactions that co-carry flux values based on physiological omics data via “GR constraints”. This method scans changes in the variabilities of metabolic fluxes in response to an artificially enforced objective flux of product formation. The gene amplification targets predicted using this method were validated by comparing the predicted effects with the previous experimental results obtained for the production of shikimic acid and putrescine in Escherichia coli. Moreover, new gene amplification targets for further enhancing putrescine production were validated through experiments involving the overexpression of each identified targeted gene under condition-controlled batch cultivation. Conclusions FVSEOF with GR constraints allows identification of gene amplification targets for metabolic engineering of microbial strains in order to enhance the production of desired bioproducts. The algorithm was validated through the

  3. Emergências hipertensivas Hypertensive emergencies

    Directory of Open Access Journals (Sweden)

    Gilson Soares Feitosa-Filho


    Full Text Available As urgências e as emergências hipertensivas são ocorrências clínicas que podem representar mais de 25% dos atendimentos a urgências médicas. O médico deverá estar habilitado a diferenciá-las, pois o prognóstico e o tratamento são distintos. Estima-se que 3% de todas as visitas às salas de emergência decorrem de elevações significativas da pressão arterial. Nos quadros relacionados a estes atendimentos, a emergência hipertensiva é a entidade clínica mais grave que merece cuidados intensivos. É caracterizada por pressão arterial marcadamente elevada e sinais de lesões de órgãos-alvo (encefalopatia, infarto agudo do miocárdio, angina instável, edema agudo de pulmão, eclâmpsia, acidente vascular encefálico. O objetivo deste estudo foi apresentar os principais pontos sobre o seu apropriado diagnóstico e tratamento. Foi realizada busca por artigos originais com os unitermos "crise hipertensiva" e "emergência hipertensiva" nas bases de dados Pubmed e MedLine nos últimos dez anos. As referências disponíveis destes artigos foram verificadas. Os artigos foram identificados e revisados e o presente estudo condensa os principais resultados descritos. Para esta revisão foram considerados ensaios clínicos em língua inglesa, estudos retrospectivos e artigos de revisão. A crise hipertensiva é a entidade clínica com aumento súbito da PA (> 180 x 120 mmHg, acompanhada por sintomas, que podem ser leves (cefaléia, tontura, zumbido ou graves (dispnéia, dor precordial, coma e até morte, com ou sem lesão aguda de órgãos-alvo. Se os sintomas forem leves e sem lesão aguda de órgãos alvos, define-se a urgência hipertensiva. Se o quadro clínico apresentar risco de vida e refletir lesão aguda de órgãos-alvo têm-se, então, a emergência hipertensiva. Muitos pacientes também apresentam uma PA elevada demais, por não usarem suas medicações, tratando-se apenas de hipertensão arterial sistêmica crônica n

  4. Gauge fluxes in F-theory compactifications

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Ling


    In this thesis, we study the geometry and physics of gauge fluxes in F-theory compactifications to four dimensions. Motivated by the phenomenological requirement of chiral matter in realistic model building scenarios, we develop methods for a systematic analysis of primary vertical G{sub 4}-fluxes on torus-fibred Calabi-Yau fourfolds. In particular, we extend the well-known description of fluxes on elliptic fibrations with sections to the more general set-up of genus-one fibrations with multi-sections. The latter are known to give rise to discrete abelian symmetries in F-theory. We test our proposal for constructing fluxes in such geometries on an explicit model with SU(5) x Z{sub 2} symmetry, which is connected to an ordinary elliptic fibration with SU(5) x U(1) symmetry by a conifold transition. With our methods we systematically verify anomaly cancellation and tadpole matching in both models. Along the way, we find a novel way of understanding anomaly cancellation in 4D F-theory in purely geometric terms. This observation is further strengthened by a similar analysis of an SU(3) x SU(2) x U(1){sup 2} model. The obvious connection of this particular model with the Standard Model is then investigated in a more phenomenologically motivated survey. There, we will first provide possible matchings of the geometric spectrum with the Standard Model states, which highlights the role of the additional U(1) factor as a selection rule. In a second step, we then utilise our novel methods on flux computations to set up a search algorithm for semi-realistic chiral spectra in our Standard- Model-like fibrations over specific base manifolds B. As a demonstration, we scan over three choices P{sup 3}, Bl{sub 1}P{sup 3} and Bl{sub 2}P{sup 3} for the base. As a result we find a consistent flux that gives the chiral Standard Model spectrum with a vector-like triplet exotic, which may be lifted by a Higgs mechanism.

  5. FluxPro: Real time monitoring and simulation system for eddy covariance flux measurement (United States)

    Kim, W.; Seo, H.; Mano, M.; Ono, K.; Miyata, A.; Yokozawa, M.


    To cope with unusual weather changes on crop cultivation in a field level, prompt and precise monitoring of photosynthesis and evapotranspiration, and those fast and reliable forecasting are indispensable. So we have developed FluxPro which is simultaneous operating system of the monitoring and the forecasting. The monitoring subsystem provides vapor and CO2 fluxes with uncertainty to understand the live condition of photosynthesis and evapotranspiration by open-path eddy covariance flux measurement (EC) system and self-developed EC tolerance analysis scheme. The forecasting subsystem serves the predicted fluxes with anomaly based on model parameter assimilation to estimate the hourly or daily water consumption and carbon assimilation during a week by multi-simulation package consisting of various models from simple to complicate. FluxPro is helpful not only to detect a critical condition of growing crop in terms of photosynthesis and evapotranspiration but also to decide time and amount of launching control for keeping those optimization condition when an unusual weather event is arisen. In our presentation, we will demonstrate the FluxPro operated at tangerine orchard in Jeju, Korea.

  6. Comparison between elementary flux modes analysis and 13C-metabolic fluxes measured in bacterial and plant cells

    Directory of Open Access Journals (Sweden)

    Dieuaide-Noubhani Martine


    Full Text Available Abstract Background 13C metabolic flux analysis is one of the pertinent ways to compare two or more physiological states. From a more theoretical standpoint, the structural properties of metabolic networks can be analysed to explore feasible metabolic behaviours and to define the boundaries of steady state flux distributions. Elementary flux mode analysis is one of the most efficient methods for performing this analysis. In this context, recent approaches have tended to compare experimental flux measurements with topological network analysis. Results Metabolic networks describing the main pathways of central carbon metabolism were set up for a bacteria species (Corynebacterium glutamicum and a plant species (Brassica napus for which experimental flux maps were available. The structural properties of each network were then studied using the concept of elementary flux modes. To do this, coefficients of flux efficiency were calculated for each reaction within the networks by using selected sets of elementary flux modes. Then the relative differences - reflecting the change of substrate i.e. a sugar source for C. glutamicum and a nitrogen source for B. napus - of both flux efficiency and flux measured experimentally were compared. For both organisms, there is a clear relationship between these parameters, thus indicating that the network structure described by the elementary flux modes had captured a significant part of the metabolic activity in both biological systems. In B. napus, the extension of the elementary flux mode analysis to an enlarged metabolic network still resulted in a clear relationship between the change in the coefficients and that of the measured fluxes. Nevertheless, the limitations of the method to fit some particular fluxes are discussed. Conclusion This consistency between EFM analysis and experimental flux measurements, validated on two metabolic systems allows us to conclude that elementary flux mode analysis could be a

  7. Oscillations in the open solar magnetic flux with a period of 1.68 years: imprint on galactic cosmic rays and implications for heliospheric shielding

    Directory of Open Access Journals (Sweden)

    A. Rouillard


    Full Text Available An understanding of how the heliosphere modulates galactic cosmic ray (GCR fluxes and spectra is important, not only for studies of their origin, acceleration and propagation in our galaxy, but also for predicting their effects (on technology and on the Earth's environment and organisms and for interpreting abundances of cosmogenic isotopes in meteorites and terrestrial reservoirs. In contrast to the early interplanetary measurements, there is growing evidence for a dominant role in GCR shielding of the total open magnetic flux, which emerges from the solar atmosphere and enters the heliosphere. In this paper, we relate a strong 1.68-year oscillation in GCR fluxes to a corresponding oscillation in the open solar magnetic flux and infer cosmic-ray propagation paths confirming the predictions of theories in which drift is important in modulating the cosmic ray flux. Key words. Interplanetary physics (Cosmic rays, Interplanetary magnetic fields

  8. Preparing for Emergency

    DEFF Research Database (Denmark)

    Melchiors, Jacob; Todsen, Tobias; Nilsson, Philip


    OBJECTIVE: Emergency cricothyrodotomy (EC) is a lifesaving procedure. Evidence-based assessment of training effects and competency levels is relevant to all departments involved in emergency airway management. As most training uses low-fidelity models, the predictive value of good performance on ...

  9. Emerging wind energy technologies

    DEFF Research Database (Denmark)

    Rasmussen, Flemming; Grivel, Jean-Claude; Faber, Michael Havbro


    This chapter will discuss emerging technologies that are expected to continue the development of the wind sector to embrace new markets and to become even more competitive.......This chapter will discuss emerging technologies that are expected to continue the development of the wind sector to embrace new markets and to become even more competitive....

  10. Emergency Notification Strategy (United States)

    Katsouros, Mark


    In higher education, the IT department is often the service provider for the institution's emergency notification system (ENS). For many institutions, the complexity of providing emergency notification to students, faculty, and staff makes using a local, on-premise solution unrealistic. But finding the right commercially hosted technical solution…

  11. Common eye emergencies

    African Journals Online (AJOL)


    Oct 11, 2007 ... Common eye emergencies may present as an acute red eye, sudden visual loss or acute ocular trauma. Most eye emergencies will require referral to an ophthalmologist after initial basic examination and primary management. A relevant history of onset and symptoms of the current problem must be ...

  12. Birth and Emergency Planning

    African Journals Online (AJOL)

    AJRH Managing Editor

    Overall, 62% had a birth plan, 74% had adequate knowledge of danger signs, while 64% and 37% reported maternal and newborn complications ... Knowledge of danger signs was associated with birth and emergency planning, and birth and emergency planning was associated with .... Materials and Methods. Study site.

  13. Emergent Collaboration on Twitter

    DEFF Research Database (Denmark)

    Lundgaard, Daniel; Razmerita, Liana; Tan, Chee-Wee


    This paper explores the organizing elements that foster emergent collaboration within large-scale communities on online social platforms like Twitter. This study is based on a case study of the #BlackLivesMatter social movement and draws on organizing dynamics and online social network literature...... foster emergent collaboration in social movements using Twitter....

  14. Emergency presurgical visit

    Directory of Open Access Journals (Sweden)

    Alfredo Castro Díaz


    Full Text Available The objective has been to create a Protocol of Structured Presurgical Visit applicable to the patients who are undergoing an emergency surgery, to provide the user and his family all the necessary cares on the basis of those nursing diagnosis that prevail in all the cases of surgical emergency interventions. The used method has been an analysis of the emergency surgical interventions more prevalent from February 2007 until October 2008 in our area (a regional hospital, and statistic of those nursing diagnosis that more frequently appeared in these interventions, the previous moment to the intervention and in addition common to all of them. The results were the following ones: the more frequent emergency operations were: Caesarean, ginecological curettage, laparotomy, help in risk childbirth, orthopaedic surgery and appendectomy. The more frequent nursing diagnosis in all the emergency operations at the previous moment of the intervention were: risk of falls, pain, anxiety, deficit of knowledge, risk of infection, movement stress syndrome, risk of hemorrhage, cutaneous integrity deterioration. The conclusion is that users present at the previous moment to an emergency operation several problems, which force to the emergency surgical ward nurse to the introduction of the nursing methodology, in order to identify the problems, to mark results and to indicate the interventions to achieve those results, besides in a humanitarian way and with quality. This can be obtained by performing a Structured Emergency Presurgical Visit.

  15. Focus on emergency medicine. (United States)


    Manuela Herrera reports from the 10th Emergency and Critical Care UK annual congress, hosted by Vets Now, which was held in Harrogate last November. More than 500 small animal veterinary surgeons, veterinary nurses, practice managers and receptionists attended the meeting to learn more about all aspects of emergency care.

  16. 7. Emergency contraception

    African Journals Online (AJOL)


    Unintended pregnancies, carrying enormous costs to individuals and societies, are largely preventable with improved use of Emergency Contraceptive pills. The full potential of emergency contraception can be realized only when people, especially women are made aware of the existence of these methods and the need.

  17. Emergence of magnetic flux from the convection zone into the corona

    DEFF Research Database (Denmark)

    Archontis, Vasilis; Moreno-insertis, F.; Galsgaard, Klaus


    Sun: corona/ Sun: magentic fields/ Sun: interior/ magnetohydrodynamics (MHD)/methods: numerical/ stars: activity......Sun: corona/ Sun: magentic fields/ Sun: interior/ magnetohydrodynamics (MHD)/methods: numerical/ stars: activity...

  18. Flux Accretion and Coronal Mass Ejection Dynamics (United States)

    Welsch, Brian


    Coronal mass ejections (CMEs) are the primary drivers of severe space weather disturbances in the heliosphere. The equations of ideal magnetohydrodynamics (MHD) have been used to model the onset and, in some cases, the subsequent acceleration of ejections. Both observations and numerical modeling, however, suggest that magnetic reconnection likely plays a major role in most, if not all, fast CMEs. Here, we theoretically investigate the dynamical effects of accretion of magnetic flux onto a rising ejection by reconnection involving the ejection's background field. This reconnection alters the magnetic structure of the ejection and its environment, thereby modifying forces acting during the eruption, generically leading to faster acceleration of the CME. Our ultimate aim is to characterize changes in CME acceleration in terms of observable properties of magnetic reconnection, such as the amount of reconnected flux, deduced from observations of flare ribbons and photospheric magnetic fields.

  19. Flux qubit to a transmission line

    Energy Technology Data Exchange (ETDEWEB)

    Haeberlein, Max; Baust, Alexander; Zhong, Ling; Gross, Rudolf [Walther-Meissner-Institut, Bayerische Akademie der Wissenschaften, Garching (Germany); Physik-Department, TU Muenchen, Garching (Germany); Nanosystems Initiative Munich (NIM), Muenchen (Germany); Anderson, Gustav; Wang, Lujun; Eder, Peter; Fischer, Michael; Goetz, Jan; Xie, Edwar; Schwarz, Manuel; Wulschner, Karl Friedrich; Deppe, Frank; Fedorov, Kirill; Huebl, Hans; Menzel, Edwin [Walther-Meissner-Institut, Bayerische Akademie der Wissenschaften, Garching (Germany); Physik-Department, TU Muenchen, Garching (Germany); Marx, Achim [Walther-Meissner-Institut, Bayerische Akademie der Wissenschaften, Garching (Germany)


    Within the last decade, superconducting qubits coupled to microwave resonators have been extensively studied within the framework of quantum electrodynamics. Ultimately, quantum computing seems within reach in such architectures. However, error correction schemes are necessary to achieve the required fidelity in multi-qubit operations, drastically increasing the number of qubits involved. In this work, we couple a flux qubit to a transmission line where it interacts with itinerant microwave photons granting access to all-optical quantum computing. In this approach, travelling photons generate entanglement between two waveguides, containing the qubit information. In this presentation, we show experimental data on flux qubits coupled to transmission lines. Furthermore, we will discuss entanglement generation between two separate paths.

  20. Anthropogenic methane ebullition and continuous flux measurement (United States)

    Alshboul, Zeyad


    Keywords: Methane, Wastewater, Effluent, Anaerobic treatment. Municipal wastewater treatment plants (WWTPs) have shown to emit significant amount of methane during treatment processes. While most of studies cover only in-plant diffusive methane flux, magnitude and sources of methane ebullition have not well assessed. Moreover, the reported results of methane emissions from WWTPs are based on low spatial and temporal resolution. Using a continuous measurement approach of methane flux rate for effluent system and secondary clarifier treatment process at one WWTP in Southwest Germany, our results show that high percentage of methane is emitted by ebullition during the anaerobic treatment (clarification pond) with high spatial and temporal variability. Our measurements revealed that no ebullition is occur at the effluent system. The observed high contribution of methane ebullition to the total in-plant methane emission, emphasizes the need for considering in-plant methane emission by ebullition as well as the spatial and temporal variability of these emissions.

  1. High flux diffractometers on reactor neutron sources (United States)

    Hewat, Alan W.


    Continuous neutron sources such as reactors can deliver a very high time-averaged flux to the sample using a relatively wide band of wavelengths, while still retaining good resolution. For example, the D20 diffractometer at ILL Grenoble, the world's highest flux neutron powder machine, can collect complete patterns at 100 ms intervals, and this has been important for the real time study of explosive SHS reactions. New very large 2D detectors, such as those recently installed on D2B and D19 at ILL, are up to an order of magnitude larger than previous designs, and will provide unmatched speed of data collection from very small samples, opening up new scientific perspectives for powder and single crystal diffraction. We will discuss future reactor based diffractometers designed for rapid data collection from small samples in special environments.

  2. Soft Supersymmetry Breaking in KKLT Flux Compactification

    CERN Document Server

    Choi, Kiwoon; Nilles, Hans Peter; Olechowski, Marek; Choi, Kiwoon; Falkowski, Adam; Nilles, Hans Peter; Olechowski, Marek


    We examine the structure of soft supersymmetry breaking terms in KKLT models of flux compactification with low energy supersymmetry. Moduli are stabilized by fluxes and nonperturbative dynamics while a de Sitter vacuum is obtained by adding supersymmetry breaking anti-branes. We discuss the characteristic pattern of mass scales in such a set-up as well as some features of 4D N=1 supergravity breakdown by anti-branes. Anomaly mediation is found to always give an important contribution and one can easily arrange for flavor-independent soft terms. In its most attractive realization, the modulus mediation is comparable to the anomaly mediation, yielding a quite distinctive sparticle spectrum. In addition, the axion component of the modulus/dilaton superfield dynamically cancels the relative CP phase between the contributions of anomaly and modulus mediation, thereby avoiding dangerous SUSY CP violation.

  3. Electric power emergency handbook

    Energy Technology Data Exchange (ETDEWEB)

    Labadie, J.R.


    The Emergency Electric Power Administration's Emergency Operations Handbook is designed to provide guidance to the EEPA organization. It defines responsibilities and describes actions performed by the government and electric utilities in planning for, and in operations during, national emergencies. The EEPA Handbook is reissued periodically to describe organizational changes, to assign new duties and responsibilities, and to clarify the responsibilities of the government to direct and coordinate the operations of the electric utility industry under emergencies declared by the President. This Handbook is consistent with the assumptions, policies, and procedures contained in the National Plan for Emergency Preparedness. Claimancy and restoration, communications and warning, and effects of nuclear weapons are subjects covered in the appendices.

  4. Magnetic flux reconstruction methods for shaped tokamaks

    Energy Technology Data Exchange (ETDEWEB)

    Tsui, Chi-Wa [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)


    The use of a variational method permits the Grad-Shafranov (GS) equation to be solved by reducing the problem of solving the 2D non-linear partial differential equation to the problem of minimizing a function of several variables. This high speed algorithm approximately solves the GS equation given a parameterization of the plasma boundary and the current profile (p` and FF` functions). The author treats the current profile parameters as unknowns. The goal is to reconstruct the internal magnetic flux surfaces of a tokamak plasma and the toroidal current density profile from the external magnetic measurements. This is a classic problem of inverse equilibrium determination. The current profile parameters can be evaluated by several different matching procedures. Matching of magnetic flux and field at the probe locations using the Biot-Savart law and magnetic Green`s function provides a robust method of magnetic reconstruction. The matching of poloidal magnetic field on the plasma surface provides a unique method of identifying the plasma current profile. However, the power of this method is greatly compromised by the experimental errors of the magnetic signals. The Casing Principle provides a very fast way to evaluate the plasma contribution to the magnetic signals. It has the potential of being a fast matching method. The performance of this method is hindered by the accuracy of the poloidal magnetic field computed from the equilibrium solver. A flux reconstruction package has been implemented which integrates a vacuum field solver using a filament model for the plasma, a multi-layer perception neural network as an interface, and the volume integration of plasma current density using Green`s functions as a matching method for the current profile parameters. The flux reconstruction package is applied to compare with the ASEQ and EFIT data. The results are promising.


    Energy Technology Data Exchange (ETDEWEB)



    The Pacific Northwest Laboratory has convened this meeting to enlist the best talents of our laboratories and industry in soliciting factual, technical information pertinent to the Pacific Northwest's Laboratory's evaluation of the potential fuel systems for the Fast Flux Test Facility. The particular factors emphasized for these fuel systems are those associated with safety, ability to meet testing objectives, and economics. The proceedings includes twenty-three presentations, along with a transcript of the discussion following each, as well as a summary discussion.

  6. Parametric amplification by coupled flux qubits


    Rehak, M.; Neilinger, P.; Grajcar, M.; Oelsner, G.; Huebner, U.; Il'ichev, E.; Meyer, H. -G.


    We report the parametric amplification of a microwave signal in a Kerr medium formed from superconducting qubits. Two mutually coupled flux qubits, embedded in the current antinode of a superconducting coplanar waveguide resonator, are used as a nonlinear element. Shared Josephson junctions provide the qubit-resonator coupling, resulting in a device with a measured gain of about 20 dB. We argue, that this arrangement represents a unit cell which can be straightforwardly extended to a quasi on...

  7. HTS flux flow devices and applications

    Energy Technology Data Exchange (ETDEWEB)

    Martens, J.; Pance, A.; Johansson, M.; Char, K.; Whiteley, S. [Conductus, Sunnyvale, CA (United States); Hou, S.; Phillips, J. [AT and T Bell Labs., Murray Hill, NJ (United States)


    Flux flow devices are three terminal active superconducting elements. Among the circuits demonstrated are mm-wave amplifiers, a fairly complete logic family and multiplexers/demultiplexers. Before it can be decided if this technology is viable for circuits of sufficient complexity to be commercially interesting, many manufacturability and materials questions must be answered. Work pertaining to these questions as well as demonstrations to date will be discussed.

  8. Periods of High Intensity Solar Proton Flux (United States)

    Xapsos, Michael A.; Stauffer, Craig A.; Jordan, Thomas M.; Adams, James H.; Dietrich, William F.


    Analysis is presented for times during a space mission that specified solar proton flux levels are exceeded. This includes both total time and continuous time periods during missions. Results for the solar maximum and solar minimum phases of the solar cycle are presented and compared for a broad range of proton energies and shielding levels. This type of approach is more amenable to reliability analysis for spacecraft systems and instrumentation than standard statistical models.

  9. Stochastic flux freezing and magnetic dynamo. (United States)

    Eyink, Gregory L


    Magnetic flux conservation in turbulent plasmas at high magnetic Reynolds numbers is argued neither to hold in the conventional sense nor to be entirely broken, but instead to be valid in a statistical sense associated to the "spontaneous stochasticity" of Lagrangian particle trajectories. The latter phenomenon is due to the explosive separation of particles undergoing turbulent Richardson diffusion, which leads to a breakdown of Laplacian determinism for classical dynamics. Empirical evidence is presented for spontaneous stochasticity, including numerical results. A Lagrangian path-integral approach is then exploited to establish stochastic flux freezing for resistive hydromagnetic equations and to argue, based on the properties of Richardson diffusion, that flux conservation must remain stochastic at infinite magnetic Reynolds number. An important application of these results is the kinematic, fluctuation dynamo in nonhelical, incompressible turbulence at magnetic Prandtl number (Pr(m)) equal to unity. Numerical results on the Lagrangian dynamo mechanisms by a stochastic particle method demonstrate a strong similarity between the Pr(m)=1 and 0 dynamos. Stochasticity of field-line motion is an essential ingredient of both. Finally, some consequences for nonlinear magnetohydrodynamic turbulence, dynamo, and reconnection are briefly considered. © 2011 American Physical Society

  10. Production of fullerenes with concentrated solar flux

    Energy Technology Data Exchange (ETDEWEB)

    Hale, M. J.; Fields, C.; Lewandowski, A.; Bingham, C.; Pitts, R.


    Research at the National Renewable Energy Laboratory (NREL) has demonstrated that fullerenes can be produced using highly concentrated sunlight from a solar furnace. Since they were first synthesized in 1989, fullerenes have been the subject of intense research. They show considerable commercial potential in advanced materials and have potential applications that include semiconductors, superconductors, high-performance metals, and medical technologies. The most common fullerene is C{sub 60}, which is a molecule with a geometry resembling a soccer ball. Graphite vaporization methods such as pulsed-laser vaporization, resistive heating, and carbon arc have been used to produce fullerenes. None of these, however, seems capable of producing fullerenes economically on a large scale. The use of concentrated sunlight may help avoid the scale-up limitations inherent in more established production processes. Recently, researchers at NREL made fullerenes in NREL`s 10 kW High Flux Solar Furnace (HFSF) with a vacuum reaction chamber designed to deliver a solar flux of 1200 W/cm{sup 2} to a graphite pellet. Analysis of the resulting carbon soot by mass spectrometry and high-pressure liquid chromatography confirmed the existence of fullerenes. These results are very encouraging and we are optimistic that concentrated solar flux can provide a means for large-scale, economical production of fullerenes. This paper presents our method, experimental apparatus, and results of fullerene production research performed with the HFSF.

  11. Greenhouse gas flux dynamics in wetlands

    Energy Technology Data Exchange (ETDEWEB)

    Silvola, J.; Alm, J.; Saarnio, S. [Joensuu Univ. (Finland). Dept. of Biology; Martikainen, P.J. [National Public Health Inst., Kuopio (Finland). Dept. of Environmental Microbiology


    Two important greenhouse gases, CO{sub 2} and CH{sub 4}, are closely connected to the carbon cycling of wetlands. Although virgin wetlands are mostly carbon accumulating ecosystems, major proportion of the CO{sub 2} bound annually in photosynthesis is released back to the atmosphere. Main portion of the carbon cycling in wetlands is quite fast while a small proportion of carbon diffusing from soil is released from organic matter, which may be ten thousand years old. Methane is formed in the anaerobic layers of wetlands, from where it is released gradually to the atmosphere. The decomposition in anaerobic conditions is very slow, which means that usually only a few percent of the annual carbon cycling takes place as methane. Research on CO{sub 2} fluxes of different virgin and managed peatlands was the main topic of this project during the first phase of SILMU. The measurements were made during two seasons in varying conditions in c. 30 study sites. In the second phase of SILMU the research topics were the spatial and temporal variation of CO{sub 2} and CH{sub 4} fluxes, the relationships between vegetation and gas fluxes as well as carbon balance studies in wetlands at some intensive sites

  12. Robustness of metabolic networks: Flux balance analysis (United States)

    Jeong, Hawoong


    Biological systems are unimaginably complex, yet also highly robust to genetic perturbations on all levels of organization. For example, the cellular metabolism of the bacterium E. coli maintains its homeostasis, often with little or no effect on the biomass yield under a considerable portion of single gene knockouts. To address the interplay between the robustness of the final biomass yield and the underlying mechanisms in the intracellular metabolism, we identify the set of intracellular metabolites of which presences are essential for the cellular- level viability via flux balance analysis. These essential metabolites exhibit the quite different characteristics both in the topological and physiological aspects of the participating reactions, compared with the case for the non-essential ones. Most importantly, it is revealed that in viable case, production and consumption rates of each essential metabolite acquire their robustness responding to the genetic perturbations, by actively reorganizing the reaction fluxes for the ultimate robustness of the biomass yield. We also find that there is strong correlation between essentiality and flux fluctuation of metabolite under the gene deletion purturbations.

  13. Metal fluxes in the Mersey Narrows

    Directory of Open Access Journals (Sweden)

    J. A. Cole


    Full Text Available Surveys of the Mersey estuary in north-west England were undertaken near the mouth of the estuary in the region known as the Mersey Narrows. Tidal fluxes of suspended and dissolved matter, particularly heavy metals, through the Mersey Narrows were investigated. This paper gives results of conducting four intensive cross-sectional surveys of the Narrows, during which currents, salinities, turbidity and water samples were obtained systematically at numerous positions, throughout selected tidal cycles. Over 300 water samples per survey were analysed to yield suspended and dissolved concentrations of the elements As, Cd, Cr, Cu, Hg, Ni, Pb and Zn, at all states of the tide. Suspended solids, concentrations and salinities were also measured. Suspended particulates account for the majority of each element present, except for cadmium, which was present in roughly equal dissolved and suspended fractions. From the tidal current and water quality data, calculations were made of hour-by-hour fluxes of each component, to show the detailed ebb and flow of heavy metals and the net tidal transport of each component. Although some differences between landward transport on the flood tide and seaward transport on the ebb were not significant, the more definite results consistently showed a seawards net transport. For spring tides of high tidal range, there was an indication of an opposite tendency, reducing the seawards transport or even reversing it, for certain suspended components. Keywords: Mersey estuary, surveys, tidal flux, dissolved metals, particulate metals, salinity, suspended particulate matter, suspended solids

  14. Are Quasar Jets Dominated by Poynting Flux?

    Energy Technology Data Exchange (ETDEWEB)

    Sikora, M


    The formation of relativistic astrophysical jets is presumably mediated by magnetic fields threading accretion disks and central, rapidly rotating objects. As it is accelerated by magnetic stresses, the jet's kinetic energy flux grows at the expense of its Poynting flux. However, it is unclear how efficient is the conversion from magnetic to kinetic energy and whether there are any observational signatures of this process. We address this issue in the context of jets in quasars. Using data from all spatial scales, we demonstrate that in these objects the conversion from Poynting-flux-dominated to matter-dominated jets is very likely to take place closer to the black hole than the region where most of the Doppler boosted radiation observed in blazars is produced. We briefly discuss the possibility that blazar activity can be induced by global MHD instabilities, e.g., via the production of localized velocity gradients that lead to dissipative events such as shocks or magnetic reconnection, where acceleration of relativistic particles and production of non-thermal flares is taking place.


    National Aeronautics and Space Administration — The Galileo Probe Net Flux Radiometer (NFR) measured net and upward radiation fluxes in Jupiter's atmosphere between about 0.44 bars and 14 bars, using five spectral...


    National Aeronautics and Space Administration — The NAMMA Senegal Radiosonde and Tower Flux data includes measurements of humidity, wind speed/direction and velocity. Additionally the Flux data includes...

  17. Advanced Tethersonde for High-Speed Flux Measurements Project (United States)

    National Aeronautics and Space Administration — Flux measurements of trace gases and other quantities, such as latent heat, are of great importance in scientific field research. One typical flux measurement setup...

  18. Direct Torque Control Induction Motor Drive with Improved Flux Response

    Directory of Open Access Journals (Sweden)

    Bhoopendra Singh


    Full Text Available Accurate flux estimation and control of stator flux by the flux control loop is the determining factor in effective implementation of DTC algorithm. In this paper a comparison of voltage-model-based flux estimation techniques for flux response improvement is carried out. The effectiveness of these methods is judged on the basis of Root Mean Square Flux Error (RMSFE, Total Harmonic Distortion (THD of stator current, and dynamic flux response. The theoretical aspects of these methods are discussed and a comparative analysis is provided with emphasis on digital signal processor (DSP based controller implementation. The effectiveness of the proposed flux estimation algorithm is investigated through simulation and experimentally validated on a test drive.


    National Aeronautics and Space Administration — The NAMMA Senegal Radiosonde and Tower Flux data includes measurements of humidity, wind speed/direction and velocity. Additionally, the flux data includes...

  20. Close to the Edge: Growth Restrained by the NAD(PH/ATP Formation Flux Ratio

    Directory of Open Access Journals (Sweden)

    Ed W. J. van Niel


    Full Text Available Most fermentative microorganisms grow well-under anaerobic conditions managing a balanced redox and appropriate energy metabolism, but a few species do exist in which cells have to cope with inadequate energy recovery or capture and/or redox balancing. Two cases of these species, i.e., the metabolically engineered Saccharomyces cerevisiae enabling it to ferment xylose and Lactobacillus reuteri fermenting glucose via the phosphoketolase pathway, are here used to introduce a quantification parameter to capture what limits the growth rate of these microorganisms under anaerobic conditions. This dimensionless parameter, the cofactor formation flux ratio (RJ, is the ratio between the redox formation flux (JNADH+NADPH, and the energy carrier formation flux (JATP, which are mainly connected to the central carbon pathways. Data from metabolic flux analyses performed in previous and present studies were used to estimate the RJ-values. Even though both microorganisms possess different central pathways, a similar relationship between RJ and the specific growth rate (μ was found. Furthermore, for both microorganisms external electron acceptors moderately reduced the RJ-value, thereby raising the μ accordingly. Based on the emerging profile of this relationship an interpretation is presented suggesting that this quantitative analysis can be applied beyond the two microbial species experimentally investigated in the current study to provide data for future targeted strain development strategies.