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Sample records for advection upstream splitting

  1. Evolution of Advection Upstream Splitting Method Schemes

    NASA Technical Reports Server (NTRS)

    Liou, Meng-Sing

    2010-01-01

    This paper focuses on the evolution of advection upstream splitting method(AUSM) schemes. The main ingredients that have led to the development of modern computational fluid dynamics (CFD) methods have been reviewed, thus the ideas behind AUSM. First and foremost is the concept of upwinding. Second, the use of Riemann problem in constructing the numerical flux in the finite-volume setting. Third, the necessity of including all physical processes, as characterised by the linear (convection) and nonlinear (acoustic) fields. Fourth, the realisation of separating the flux into convection and pressure fluxes. The rest of this review briefly outlines the technical evolution of AUSM and more details can be found in the cited references. Keywords: Computational fluid dynamics methods, hyperbolic systems, advection upstream splitting method, conservation laws, upwinding, CFD

  2. Higher-order flux difference splitting schemes for the Euler equations using upstream interpolations

    NASA Technical Reports Server (NTRS)

    Yang, J. Y.

    1986-01-01

    A class of explicit two time-level, 2p + 1 space-point, (2p 1)-th order, upwind-biased flux difference splitting schemes are proposed for the numerical advection based on Lagrange's interpolation, and the method is an accord with the physical domain of dependence. A normalized Jacobian coefficient matrix is introduced to convert the schemes to hyperbolic systems of conservation laws, and approaches to make the higher-order schemes total variation stable are discussed. Accuracy and stability of the present schemes are examined, and implicit total variation diminishing schemes are developed for steady-state calculations.Application to gasdynamic problems for both steady and unsteady flows covering a wide range of Mach numbers is considered, and results for a blast wave passing a cylinder, and head-on collision of two blast waves over a circular arc, are presented. The flow patterns were found to be symmetric, and good resolution of flow structures was obtained.

  3. A flux-splitting method for hyperbolic-equation system of magnetized electron fluids in quasi-neutral plasmas

    NASA Astrophysics Data System (ADS)

    Kawashima, Rei; Komurasaki, Kimiya; Schönherr, Tony

    2016-04-01

    A flux-splitting method is proposed for the hyperbolic-equation system (HES) of magnetized electron fluids in quasi-neutral plasmas. The numerical fluxes are split into four categories, which are computed by using an upwind method which incorporates a flux-vector splitting (FVS) and advection upstream splitting method (AUSM). The method is applied to a test calculation condition of uniformly distributed and angled magnetic lines of force. All of the pseudo-time advancement terms converge monotonically and the conservation laws are strictly satisfied in the steady state. The calculation results are compared with those computed by using the elliptic-parabolic-equation system (EPES) approach using a magnetic-field-aligned mesh (MFAM). Both qualitative and quantitative comparisons yield good agreements of results, indicating that the HES approach with the flux-splitting method attains a high computational accuracy.

  4. Fast multigrid solution of the advection problem with closed characteristics

    SciTech Connect

    Yavneh, I.; Venner, C.H.; Brandt, A.

    1996-12-31

    The numerical solution of the advection-diffusion problem in the inviscid limit with closed characteristics is studied as a prelude to an efficient high Reynolds-number flow solver. It is demonstrated by a heuristic analysis and numerical calculations that using upstream discretization with downstream relaxation-ordering and appropriate residual weighting in a simple multigrid V cycle produces an efficient solution process. We also derive upstream finite-difference approximations to the advection operator, whose truncation terms approximate {open_quotes}physical{close_quotes} (Laplacian) viscosity, thus avoiding spurious solutions to the homogeneous problem when the artificial diffusivity dominates the physical viscosity.

  5. VAC: Versatile Advection Code

    NASA Astrophysics Data System (ADS)

    Tóth, Gábor; Keppens, Rony

    2012-07-01

    The Versatile Advection Code (VAC) is a freely available general hydrodynamic and magnetohydrodynamic simulation software that works in 1, 2 or 3 dimensions on Cartesian and logically Cartesian grids. VAC runs on any Unix/Linux system with a Fortran 90 (or 77) compiler and Perl interpreter. VAC can run on parallel machines using either the Message Passing Interface (MPI) library or a High Performance Fortran (HPF) compiler.

  6. A novel second-order flux splitting for ideal magnetohydrodynamics

    NASA Astrophysics Data System (ADS)

    Borah, Kalpajyoti; Natarajan, Ganesh; Dass, Anoop K.

    2016-05-01

    A new flux splitting scheme based on wave-particle behaviour is developed for one-dimensional ideal magnetohydrodynamics. We exploit the idea that while ideal magnetohydrodynamics equations are non-convex with non-homogeneous fluxes as opposed to their hydrodynamic counterparts, they exhibit an overall wave-like structure. The proposed approach splits the flux vector into three distinct parts: the particle-like transport part and the wave-like pressure and magnetic parts, with the latter vanishing for pure hydrodynamics. The pressure part of the fluxes satisfy homogeneity property and the split flux Jacobians are constructed with a provision to regulate the numerical dissipation. The magnetic part of the fluxes however is non-homogeneous and is treated using a central scheme with artificial viscosity. This disparate treatment of the individual components of the total flux vector results in a scheme with a central-upwind character that can be implemented with low computational effort. Referred to as Magneto-acoustic Wave Particle Splitting (MWPS) scheme, it is extended to second-order accuracy by using slope limiters incorporated through the solution-dependent weighted least squares approach for gradient calculations. Several one-dimensional MHD problems are numerically solved to highlight the accuracy, positivity preservation and robustness of the MWPS scheme and comparative studies show that MWPS performs at least as well as the Advection Upstream Splitting Method (AUSM) and even outperforms it for some test cases.

  7. The 'optimum' upwind advection on a triangular mesh

    NASA Technical Reports Server (NTRS)

    Roe, P. L.

    1990-01-01

    For advection schemes based on fluctuation splitting, a design criterion of optimizing the time step leads to linear schemes that coincide with those designed for least truncation error. A further stage of optimizing the time step using a nonlinear positivity criterion, leads to considerable further gains in resolution.

  8. AN EULERIAN-LAGRANGIAN LOCALIZED ADJOINT METHOD FOR THE ADVECTION-DIFFUSION EQUATION

    EPA Science Inventory

    Many numerical methods use characteristic analysis to accommodate the advective component of transport. Such characteristic methods include Eulerian-Lagrangian methods (ELM), modified method of characteristics (MMOC), and operator splitting methods. A generalization of characteri...

  9. EULERIAN-LAGRANGIAN LOCALIZED ADJOINT METHOD FOR THE ADVECTION-DIFFUSION EQUATION

    EPA Science Inventory

    Many numerical methods use characteristic analysis to accommodate the advective component of transport. uch characteristic methods include Eulerian-Lagrangian methods (ELM), modified method of characteristics (MMOC), and operator splitting methods. eneralization of characteristic...

  10. Concentration through large advection

    NASA Astrophysics Data System (ADS)

    Aleja, D.; López-Gómez, J.

    2014-11-01

    In this paper we extend the elegant results of Chen, Lam and Lou [6, Section 2], where a concentration phenomenon was established as the advection blows up, to a general class of adventive-diffusive generalized logistic equations of degenerate type. Our improvements are really sharp as we allow the carrying capacity of the species to vanish in some subdomain with non-empty interior. The main technical devices used in the derivation of the concentration phenomenon are Proposition 3.2 of Cano-Casanova and López-Gómez [5], Theorem 2.4 of Amann and López-Gómez [1] and the classical Harnack inequality. By the relevance of these results in spatial ecology, complete technical details seem imperative, because the proof of Theorem 2.2 of [6] contains some gaps originated by an “optimistic” use of Proposition 3.2 of [5]. Some of the general assumptions of [6] are substantially relaxed.

  11. LAYER DEPENDENT ADVECTION IN CMAQ

    EPA Science Inventory

    The advection methods used in CMAQ require that the Courant-Friedrichs-Lewy (CFL) condition be satisfied for numerical stability and accuracy. In CMAQ prior to version 4.3, the ADVSTEP algorithm established CFL-safe synchronization and advection timesteps that were uniform throu...

  12. Advection around ventilated U-shaped burrows: A model study

    NASA Astrophysics Data System (ADS)

    Brand, Andreas; Lewandowski, JöRg; Hamann, Enrico; Nützmann, Gunnar

    2013-05-01

    Advective transport in the porous matrix of sediments surrounding burrows formed by fauna such as Chironomus plumosus has been generally neglected. A positron emission tomography study recently revealed that the pumping activity of the midge larvae can indeed induce fluid flow in the sediment. We present a numerical model study which explores the conditions at which advective transport in the sediment becomes relevant. A 0.15 m deep U-shaped burrow with a diameter of 0.002 m within the sediment was represented in a 3-D domain. Fluid flow in the burrow was calculated using the Navier-Stokes equation for incompressible laminar flow in the burrow, and flow in the sediment was described by Darcy's law. Nonreactive and reactive transport scenarios were simulated considering diffusion and advection. The pumping activity of the model larva results in considerable advective flow in the sediment at reasonable high permeabilities with flow velocities of up to 7.0 × 10-6 m s-1 close to the larva for a permeability of 3 × 10-12 m2. At permeabilities below 7 × 10-13 m2 advection is negligible compared to diffusion. Reactive transport simulations using first-order kinetics for oxygen revealed that advective flux into the sediment downstream of the pumping larva enhances sedimentary uptake, while the advective flux into the burrow upstream of the larvae inhibits diffusive sedimentary uptake. Despite the fact that both effects cancel each other with respect to total solute uptake, the advection-induced asymmetry in concentration distribution can lead to a heterogeneous solute and redox distribution in the sediment relevant to complex reaction networks.

  13. Investigation of Convection and Pressure Treatment with Splitting Techniques

    NASA Technical Reports Server (NTRS)

    Thakur, Siddharth; Shyy, Wei; Liou, Meng-Sing

    1995-01-01

    Treatment of convective and pressure fluxes in the Euler and Navier-Stokes equations using splitting formulas for convective velocity and pressure is investigated. Two schemes - controlled variation scheme (CVS) and advection upstream splitting method (AUSM) - are explored for their accuracy in resolving sharp gradients in flows involving moving or reflecting shock waves as well as a one-dimensional combusting flow with a strong heat release source term. For two-dimensional compressible flow computations, these two schemes are implemented in one of the pressure-based algorithms, whose very basis is the separate treatment of convective and pressure fluxes. For the convective fluxes in the momentum equations as well as the estimation of mass fluxes in the pressure correction equation (which is derived from the momentum and continuity equations) of the present algorithm, both first- and second-order (with minmod limiter) flux estimations are employed. Some issues resulting from the conventional use in pressure-based methods of a staggered grid, for the location of velocity components and pressure, are also addressed. Using the second-order fluxes, both CVS and AUSM type schemes exhibit sharp resolution. Overall, the combination of upwinding and splitting for the convective and pressure fluxes separately exhibits robust performance for a variety of flows and is particularly amenable for adoption in pressure-based methods.

  14. Upstream waves at Uranus

    NASA Technical Reports Server (NTRS)

    Russell, C. T.; Lepping, R. P.; Smith, C. W.

    1990-01-01

    Since the Mach number of the solar wind increases with increasing heliocentric distance, the ratio of thermal to magnetic pressure, or beta, of the Uranian magnetosheath is expected to be much higher than in the terrestrial magnetosheath. Consistent with this expectation, the magnetosheat is observed to be extremely turbulent, and many particles may leak back upstream into the solar wind and/or be scattered from the bow shock. In accord with the expected presence of backstreaming particles, waves of the type associated with terrestrial backstreaming particles are seen outbound along the trajectory of Voyager in the preshock solar wind with frequencies close to 0.001 Hz. The wave frequency is close to that expected for upstream waves based on measurements closer to the sun. Upstream from the bow shock, the magnetic field was found to be much weaker than expected from observations in the inner solar system. The cause of this depression is unlikely to be the upstream particles; rather, the cause is probably intrinsic to the solar wind such as reconnection across the heliospheric current sheet.

  15. Unification of some advection schemes in two dimensions

    NASA Technical Reports Server (NTRS)

    Sidilkover, D.; Roe, P. L.

    1995-01-01

    The relationship between two approaches towards construction of genuinely two-dimensional upwind advection schemes is established. One of these approaches is of the control volume type applicable on structured cartesian meshes. It resulted in the compact high resolution schemes capable of maintaining second order accuracy in both homogeneous and inhomogeneous cases. Another one is the fluctuation splitting approach, which is well suited for triangular (and possibly) unstructured meshes. Understanding the relationship between these two approaches allows us to formulate here a new fluctuation splitting high resolution (i.e. possible use of artificial compression, while maintaining positivity property) scheme. This scheme is shown to be linearity preserving in inhomogeneous as well as homogeneous cases.

  16. Upstream waves at Mars

    NASA Technical Reports Server (NTRS)

    Russell, C. T.; Luhmann, J. G.; Schwingenschuh, K.; Riedler, W.; Eroshenko, E.

    1992-01-01

    Weak, about 0.15 nT, narrow band emissions at the proton gyro frequency are observed by the Phobos magnetometer MAGMA, upstream from the bow shock of Mars. These waves are left-hand elliptically polarized. They may be associated with the pick up of protons from the Martian hydrogen exosphere. Strong turbulence, similar to that observed at the terrestrial bow shock, is found on occasion in the upstream region when the IMF connects to the bow shock. On two occasions this turbulence occurred when the spacecraft crossed the orbit of Phobos. This coincidence raises the possibility that material in the orbits of Phobos interacts with the solar wind in such a way to either affect the direction of the IMF or to cause instabilities in the solar wind plasma. However, since on a third occasion these waves did not occur, these waves may be shock associated rather than Phobos associated.

  17. Upstream health law.

    PubMed

    Sage, William M; McIlhattan, Kelley

    2014-01-01

    For the first time, entrepreneurs are aggressively developing new technologies and business models designed to improve individual and population health, not just to deliver specialized medical care. Consumers of these goods and services are not yet "patients"; they are simply people. As this sector of the health care industry expands, it is likely to require new forms of legal governance, which we term "upstream health law." PMID:25565619

  18. Arbitrary-order difference schemes for solving linear advection equations with constant coefficients by the Godunov method with antidiffusion

    NASA Astrophysics Data System (ADS)

    Moiseev, N. Ya.; Silant'eva, I. Yu.

    2008-07-01

    An approach to the construction of second-and higher order accurate difference schemes in time and space is described for solving the linear one-and multidimensional advection equations with constant coefficients by the Godunov method with antidiffusion. The differential approximations for schemes of up to the fifth order are constructed and written. For multidimensional advection equations with constant coefficients, it is shown that Godunov schemes with splitting over spatial variables are preferable, since they have a smaller truncation error than schemes without splitting. The high resolution and efficiency of the difference schemes are demonstrated using test computations.

  19. An evaluation and intercomparison of four new advection schemes for use in global chemistry models

    NASA Astrophysics Data System (ADS)

    Petersen, Arthur C.; Spee, Edwin J.; van Dop, Han; Hundsdorfer, Willem

    1998-08-01

    The need to use a higher spatial resolution and to include more chemical species in global atmospheric chemistry models has led to a demand for efficient advection schemes with high accuracy. We test four newly developed three-dimensional advection schemes named Mol-rg, Split-u, Split-us, and Split-rg. We compare the new schemes with the existing schemes Slopes and Second Moments, both implemented on a uniform grid. Mol-rg and Split-rg make use of a reduced grid. Split-us is an unconditionally stable scheme on a uniform grid. Two tests are performed with all schemes: a solid-body rotation test and a radon transport test. The radon transport test is performed with the off-line global tracer model TM2. The solid-body rotation test shows that none of the new schemes generates undershoot and overshoot and that all of them are mass conservative. Slopes and Second Moments both generate small undershoot and overshoot at all resolutions. The accuracy of the new and old schemes for rotation of a smooth profile is similar for the horizontal resolutions studied. Since the new schemes are slightly more diffusive than the old schemes, they perform worse for rotation of a cone. The radon test shows that the errors related to the numerical schemes are much smaller than other model errors. The main advantage of the new schemes is that they use 75% and 90% less memory than Slopes and Second Moments, respectively. At horizontal resolutions higher than 5° × 5° Split-us and Split-rg are the most efficient of the schemes in terms of cpu time. The new advection schemes are available through Internet.

  20. Split gland

    DOEpatents

    Petranto, J.J.

    1989-09-05

    A split gland having only three parts is described. The gland has substantially the same stability to the relative motion of the constituent half-gland members during the attachment process to a female fitting as have more complicated designs. Ease of manufacture and use result from the reduction in complexity of the present invention. 15 figs.

  1. Split gland

    DOEpatents

    Petranto, Joseph J.

    1989-01-01

    A split gland having only three parts is described. The gland has substantially the same stability to the relative motion of the constituent half-gland members during the attachment process to a female fitting as have more complicated designs. Ease of manufacture and use result from the reduction in complexity of the present invention.

  2. Equivalence of Fluctuation Splitting and Finite Volume for One-Dimensional Gas Dynamics

    NASA Technical Reports Server (NTRS)

    Wood, William A.

    1997-01-01

    The equivalence of the discretized equations resulting from both fluctuation splitting and finite volume schemes is demonstrated in one dimension. Scalar equations are considered for advection, diffusion, and combined advection/diffusion. Analysis of systems is performed for the Euler and Navier-Stokes equations of gas dynamics. Non-uniform mesh-point distributions are included in the analyses.

  3. An efficient horizontal advection scheme for the modeling of global transport of constituents

    SciTech Connect

    Hundsdorfer, W.; Spee, E.J.

    1995-12-01

    In this paper the authors consider a dimensional-splitting scheme for horizontal advection on a sphere with a uniform longitude-latitude grid. The 1D subprocesses that arise within the splitting are solved with an explicit finite-volume type scheme, which is made unconditionally stable by allowing the stencil to vary with the Courant numbers. The scheme is made positive by flux limiting. For the inaccuracies at the poles some special measures are discussed. Numerical tests show that the scheme is almost shape preserving and conservative, and it gives accurate results at low computational costs. 23 refs., 7 figs., 1 tab.

  4. Surfzone alongshore advective accelerations: observations and modeling

    NASA Astrophysics Data System (ADS)

    Hansen, J.; Raubenheimer, B.; Elgar, S.

    2014-12-01

    The sources, magnitudes, and impacts of non-linear advective accelerations on alongshore surfzone currents are investigated with observations and a numerical model. Previous numerical modeling results have indicated that advective accelerations are an important contribution to the alongshore force balance, and are required to understand spatial variations in alongshore currents (which may result in spatially variable morphological change). However, most prior observational studies have neglected advective accelerations in the alongshore force balance. Using a numerical model (Delft3D) to predict optimal sensor locations, a dense array of 26 colocated current meters and pressure sensors was deployed between the shoreline and 3-m water depth over a 200 by 115 m region near Duck, NC in fall 2013. The array included 7 cross- and 3 alongshore transects. Here, observational and numerical estimates of the dominant forcing terms in the alongshore balance (pressure and radiation-stress gradients) and the advective acceleration terms will be compared with each other. In addition, the numerical model will be used to examine the force balance, including sources of velocity gradients, at a higher spatial resolution than possible with the instrument array. Preliminary numerical results indicate that at O(10-100 m) alongshore scales, bathymetric variations and the ensuing alongshore variations in the wave field and subsequent forcing are the dominant sources of the modeled velocity gradients and advective accelerations. Additional simulations and analysis of the observations will be presented. Funded by NSF and ASDR&E.

  5. Advection fog formation in a polluted atmosphere

    SciTech Connect

    Hung, R.J.; Liaw, G.S.

    1981-01-01

    Large quantities of atmospheric aerosols with composition SO/sub 4//sup 2 -/, NO/sub 3//sup -/ and NH/sub 4//sup +/ have been detected in highly industrialized areas. The major portions of aerosol products are the results of energy related fuel combustion. Both microphysical and macrophysical processes are considered in investigating the time dependent evolution of the saturation spectra of condensation nuclei associated with both polluted and clean atmospheres during the time periods of advection fog formation. The results show that the condensation nuclei associated with a polluted atmosphere provide more favorable conditions than condensation nuclei associated with a clean atmosphere to produce dense advection fog, and that attaining a certain degree of supersaturation is not necessarily required for the formation of advection fog with condensation nuclei associated with a polluted atmosphere for monodisperse distribution.

  6. Antidiffusive velocities for multipass donor cell advection

    SciTech Connect

    Margolin, L.; Smolarkiewicz, P.K.

    1999-01-01

    Multidimensional positive definite advection transport algorithm (MPDATA) is an iterative process for approximating the advection equation, which uses a donor cell approximation to compensate for the truncation error of the originally specified donor cell scheme. This step may be repeated an arbitrary number of times, leading to successfully more accurate solutions to the advection equation. In this paper, the authors show how to sum the successive approximations analytically to find a single antidiffusive velocity that represents the effects of an arbitrary number of passes. The analysis is first done in one dimension to illustrate the method and then is repeated in two dimensions. The existence of cross terms in the truncation analysis of the two-dimensional equations introduces an extra complication into the calculation. The authors discuss the implementation of the antidiffusive velocities and provide some examples of applications, including a third-order accurate scheme.

  7. MAGNETIC ADVECTION DUE TO DIFFUSIVITY GRADIENTS

    NASA Astrophysics Data System (ADS)

    Zita, E. J.

    2009-12-01

    We derive and discuss an important source of advection of magnetic fields in plasmas, for a completely general case. Magnetic diffusivity is proportional to electrical resistivity: where the value this parameter is high, it is well known that magnetic fields can leak (or diffuse) rapidly into (or out) of the plasma. Magnetohydrodynamic lore has it that where gradients, or changes in space, of the value of the diffusivity are high, magnetic fields can have enhanced flow (or advection). We derive this phenomenon rigorously, compare our results to other work in the literature, and discuss its implications, especially for kinematic dynamos. As an extra mathematical bonus, we find that the magnetic advection due to diffusivity gradients can be expressed in terms of a diffusion equation within the induction equation, making its computational implementation especially simple.

  8. Efficient mass transport by optical advection

    NASA Astrophysics Data System (ADS)

    Kajorndejnukul, Veerachart; Sukhov, Sergey; Dogariu, Aristide

    2015-10-01

    Advection is critical for efficient mass transport. For instance, bare diffusion cannot explain the spatial and temporal scales of some of the cellular processes. The regulation of intracellular functions is strongly influenced by the transport of mass at low Reynolds numbers where viscous drag dominates inertia. Mimicking the efficacy and specificity of the cellular machinery has been a long time pursuit and, due to inherent flexibility, optical manipulation is of particular interest. However, optical forces are relatively small and cannot significantly modify diffusion properties. Here we show that the effectiveness of microparticle transport can be dramatically enhanced by recycling the optical energy through an effective optical advection process. We demonstrate theoretically and experimentally that this new advection mechanism permits an efficient control of collective and directional mass transport in colloidal systems. The cooperative long-range interaction between large numbers of particles can be optically manipulated to create complex flow patterns, enabling efficient and tunable transport in microfluidic lab-on-chip platforms.

  9. 3D Flow Visualization Using Texture Advection

    NASA Technical Reports Server (NTRS)

    Kao, David; Zhang, Bing; Kim, Kwansik; Pang, Alex; Moran, Pat (Technical Monitor)

    2001-01-01

    Texture advection is an effective tool for animating and investigating 2D flows. In this paper, we discuss how this technique can be extended to 3D flows. In particular, we examine the use of 3D and 4D textures on 3D synthetic and computational fluid dynamics flow fields.

  10. DPDC (double-pass donor cell): A second-order monotone scheme for advection

    SciTech Connect

    Beason, C W; Margolin, L G

    1988-09-26

    We are developing a new, second-order, monotone scheme for advection. DPDC (i.e., double-pass donor cell) is based on Smolarkiewicz' simple, positive definite method. Both schemes are multipass methods in which upstream approximations to the truncation error are subtracted from the equations. We describe two significant improvements to Smolarkiewicz' method. First, we use a local gauge transformation to convert the method from being positive definite to the stronger condition of being monotone. Second, we analytically approximate the sum of the corrections of all the passes to use in a single corrective pass. This increases the accuracy of the method, but does not increase the order of accuracy. We compare DPDC with van Leer's method for advection of several different pulses in a constant velocity field. 5 refs., 4 figs.

  11. Hydraulic jumps with upstream shear

    NASA Astrophysics Data System (ADS)

    Ogden, Kelly; Helfrich, Karl

    2013-11-01

    Hydraulic jumps in flows with background shear are investigated, motivated by applications such as the flow over sills in Knight Inlet and the Pre-Bosphorus Channel. The full solution space and allowable solutions to several two-layer theories for hydraulic jumps with upstream shear are identified. The two-layer theories considered, including a recent theory by Borden et al. (JFM, 2012), are distinguished by how dissipation is partitioned between the layers. It is found that upstream shear with a faster and thinner lower layer causes an increase in bore speed, for a given jump height. Further, these two-layer solutions only exist for a limited range of upstream shear. 2D numerical simulations are conducted, guided by the two-layer theory solution space, and the results are compared to the theories. The simulations show the qualitative types of hydraulic transitions that occur, including undular bores, fully turbulent jumps, and conjugate state-like solutions; the type depends on the jump height and upstream shear for fixed upstream layer depths. Numerical simulations are used to investigate the mixing. Finally, a few 3D numerical simulations were made and are found to be consistent with the 2D results.

  12. Upstream Swimming in Microbiological Flows.

    PubMed

    Mathijssen, Arnold J T M; Shendruk, Tyler N; Yeomans, Julia M; Doostmohammadi, Amin

    2016-01-15

    Interactions between microorganisms and their complex flowing environments are essential in many biological systems. We develop a model for microswimmer dynamics in non-Newtonian Poiseuille flows. We predict that swimmers in shear-thickening (-thinning) fluids migrate upstream more (less) quickly than in Newtonian fluids and demonstrate that viscoelastic normal stress differences reorient swimmers causing them to migrate upstream at the centerline, in contrast to well-known boundary accumulation in quiescent Newtonian fluids. Based on these observations, we suggest a sorting mechanism to select microbes by swimming speed. PMID:26824571

  13. Upstream Swimming in Microbiological Flows

    NASA Astrophysics Data System (ADS)

    Mathijssen, Arnold J. T. M.; Shendruk, Tyler N.; Yeomans, Julia M.; Doostmohammadi, Amin

    2016-01-01

    Interactions between microorganisms and their complex flowing environments are essential in many biological systems. We develop a model for microswimmer dynamics in non-Newtonian Poiseuille flows. We predict that swimmers in shear-thickening (-thinning) fluids migrate upstream more (less) quickly than in Newtonian fluids and demonstrate that viscoelastic normal stress differences reorient swimmers causing them to migrate upstream at the centerline, in contrast to well-known boundary accumulation in quiescent Newtonian fluids. Based on these observations, we suggest a sorting mechanism to select microbes by swimming speed.

  14. MAST solution of advection problems in irrotational flow fields

    NASA Astrophysics Data System (ADS)

    Aricò, Costanza; Tucciarelli, Tullio

    2007-03-01

    A new numerical-analytical Eulerian procedure is proposed for the solution of convection-dominated problems in the case of existing scalar potential of the flow field. The methodology is based on the conservation inside each computational elements of the 0th and 1st order effective spatial moments of the advected variable. This leads to a set of small ODE systems solved sequentially, one element after the other over all the computational domain, according to a MArching in Space and Time technique. The proposed procedure shows the following advantages: (1) it guarantees the local and global mass balance; (2) it is unconditionally stable with respect to the Courant number, (3) the solution in each cell needs information only from the upstream cells and does not require wider and wider stencils as in most of the recently proposed higher-order methods; (4) it provides a monotone solution. Several 1D and 2D numerical test have been performed and results have been compared with analytical solutions, as well as with results provided by other recent numerical methods.

  15. Passive advection in a collisionless plasma

    NASA Astrophysics Data System (ADS)

    Kanekar, Anjor; Schekochihin, Alexander; Hammett, Greg; Dorland, William; Loureiro, Nuno

    2014-10-01

    We consider a simple kinetic model for the evolution of the particle distribution function in a magnetized turbulent plasma that includes both phase mixing (Landau damping) and advection by a stochastic velocity field: a ``kinetic passive scalar'' in the Batchelor regime. The advection due to stochastic velocity field allows for a stochastic version of the plasma echo by coupling the ``phase-mixing'' and the ``un-phase-mixing'' components of the free energy. We have developed a new analytical framework to diagnose the efficiency of such coupling. We have also developed a new GPU code named Gandalf that solves this kinetic model numerically. In this poster, we shall present numerical and analytical results related to this work.

  16. Antidiffusive velocities for multipass donor cell advection

    SciTech Connect

    Margolin, L.G. ); Smolarkiewicz, P.K. )

    1989-12-01

    Smolarkiewicz describes an iterative process for approximating the advection equation. Basically, he uses a donor cell approximation to correct for the truncation error of the originally specified donor cell scheme. This step may be repeated an arbitrary number of times leading to successively more accurate solutions to the advection equation. In this report, we show how to sum the successive approximations analytically to find a single antidiffusive velocity that represents the effects of an arbitrary number of passes. The analysis is first done dimension to illustrate the method. The analysis is then repeated in two dimensions. The existence of cross terms in the truncation analysis of the two-dimensional equations introduces an extra complication into the calculation. We discuss the implementation of our new antidiffusive velocities and provide some examples of applications. 6 refs., 5 figs., 4 tabs.

  17. CONTAMINANT TRANSPORT IN SEDIMENT UNDER THE INFLUENCE OF ADVECTIVE FLUX

    EPA Science Inventory

    Chemical flux across the sediment/water interface is controlled by a combination of diffusive, dispersive and advective processes. The advective process is a function of submarine groundwater discharge and tidal effects. In areas where surface water interacts with groundwater, ...

  18. Distributed Parallel Particle Advection using Work Requesting

    SciTech Connect

    Muller, Cornelius; Camp, David; Hentschel, Bernd; Garth, Christoph

    2013-09-30

    Particle advection is an important vector field visualization technique that is difficult to apply to very large data sets in a distributed setting due to scalability limitations in existing algorithms. In this paper, we report on several experiments using work requesting dynamic scheduling which achieves balanced work distribution on arbitrary problems with minimal communication overhead. We present a corresponding prototype implementation, provide and analyze benchmark results, and compare our results to an existing algorithm.

  19. High Order Semi-Lagrangian Advection Scheme

    NASA Astrophysics Data System (ADS)

    Malaga, Carlos; Mandujano, Francisco; Becerra, Julian

    2014-11-01

    In most fluid phenomena, advection plays an important roll. A numerical scheme capable of making quantitative predictions and simulations must compute correctly the advection terms appearing in the equations governing fluid flow. Here we present a high order forward semi-Lagrangian numerical scheme specifically tailored to compute material derivatives. The scheme relies on the geometrical interpretation of material derivatives to compute the time evolution of fields on grids that deform with the material fluid domain, an interpolating procedure of arbitrary order that preserves the moments of the interpolated distributions, and a nonlinear mapping strategy to perform interpolations between undeformed and deformed grids. Additionally, a discontinuity criterion was implemented to deal with discontinuous fields and shocks. Tests of pure advection, shock formation and nonlinear phenomena are presented to show performance and convergence of the scheme. The high computational cost is considerably reduced when implemented on massively parallel architectures found in graphic cards. The authors acknowledge funding from Fondo Sectorial CONACYT-SENER Grant Number 42536 (DGAJ-SPI-34-170412-217).

  20. Efficient mass transport by optical advection

    PubMed Central

    Kajorndejnukul, Veerachart; Sukhov, Sergey; Dogariu, Aristide

    2015-01-01

    Advection is critical for efficient mass transport. For instance, bare diffusion cannot explain the spatial and temporal scales of some of the cellular processes. The regulation of intracellular functions is strongly influenced by the transport of mass at low Reynolds numbers where viscous drag dominates inertia. Mimicking the efficacy and specificity of the cellular machinery has been a long time pursuit and, due to inherent flexibility, optical manipulation is of particular interest. However, optical forces are relatively small and cannot significantly modify diffusion properties. Here we show that the effectiveness of microparticle transport can be dramatically enhanced by recycling the optical energy through an effective optical advection process. We demonstrate theoretically and experimentally that this new advection mechanism permits an efficient control of collective and directional mass transport in colloidal systems. The cooperative long-range interaction between large numbers of particles can be optically manipulated to create complex flow patterns, enabling efficient and tunable transport in microfluidic lab-on-chip platforms. PMID:26440069

  1. Advection and diffusion in shoreline change prediction

    NASA Astrophysics Data System (ADS)

    Anderson, T. R.; Frazer, L. N.

    2010-12-01

    We added longshore advection and diffusion to the simple cross-shore rate calculation method, as used widely by the USGS and others, to model historic shorelines and to predict future shoreline positions; and applied this to Hawaiian Island beach data. Aerial photographs, sporadically taken throughout the past century, yield usable, albeit limited, historic shoreline data. These photographs provide excellent spatial coverage, but poor temporal resolution, of the shoreline. Due to the sparse historic shoreline data, and the many natural and anthropogenic events influencing coastlines, we constructed a simplistic shoreline change model that can identify long-term behavior of a beach. Our new, two-dimensional model combines the simple rate method to accommodate for cross-shore sediment transport with the classic Pelnard-Considère model for diffusion, as well as a longshore advection speed term. Inverse methods identify cross-shore rate, longshore advection speed, and longshore diffusivity down a sandy coastline. A spatial averaging technique then identifies shoreline segments where one parameter can reasonably account for the cross-shore and longshore transport rates in that area. This produces model results with spatial resolution more appropriate to the temporal spacing of the data. Because changes in historic data can be accounted for by varying degrees of cross-shore and longshore sediment transport - for example, beach erosion can equally be explained by sand moving either off-shore or laterally - we tested several different model scenarios on the data: allowing only cross-shore sediment movement, only longshore movement, and a combination of the two. We used statistical information criteria to determine both the optimal spatial resolution and best-fitting scenario. Finally, we employed a voting method predicting the relaxed shoreline position over time.

  2. Coupled ensemble flow line advection and analysis.

    PubMed

    Guo, Hanqi; Yuan, Xiaoru; Huang, Jian; Zhu, Xiaomin

    2013-12-01

    Ensemble run simulations are becoming increasingly widespread. In this work, we couple particle advection with pathline analysis to visualize and reveal the differences among the flow fields of ensemble runs. Our method first constructs a variation field using a Lagrangian-based distance metric. The variation field characterizes the variation between vector fields of the ensemble runs, by extracting and visualizing the variation of pathlines within ensemble. Parallelism in a MapReduce style is leveraged to handle data processing and computing at scale. Using our prototype system, we demonstrate how scientists can effectively explore and investigate differences within ensemble simulations. PMID:24051840

  3. Experiments in Advective and Turbulent Hyporheic Pumping

    NASA Astrophysics Data System (ADS)

    Mccluskey, A. H.; Grant, S.; Stewardson, M. J.

    2014-12-01

    Hyporheic exchange (HE) is the mixing of stream and subsurface waters beneath the sediment-water interface (SWI). At the patch and reach scales, HE is dominated by periodic upwelling and downwelling zones, induced by pressure variation and processes within the turbulent boundary layer (TBL). This can be caused by (1) the geometry of the stream, imposing a stationary wave at the SWI or (2) by a travelling wave associated with the propagation of turbulent pressure waves generated from the TBL. Case (1) has generally been the favoured model of hyporheic exchange and has been referred to as hyporheic 'pumping' by Elliott and Brooks, and subsequently others. Case (2) can be termed turbulent pumping, and has been proposed as a mechanism to model the combined effects of turbulent dispersion alongside steady-state advection. While this has been represented numerically and analytically, conjecture remains about the physical representation of these combined processes. We present initial results from experiments undertaken to classify the spatial and temporal characteristics of pressure variation at and beneath the SWI, with a periodic sinusoidal geometry of wavelength 0.28m and height 0.02m. As an initial characterisation, the advective flow profile has been examined using time-lapse photography of dyes released across the span of a periodic downwelling zone. These tracer tests confirmed delineation of isolated upwelling and downwelling cells as noted by previous authors in modelling studies. However, their distribution deviates from the typical pumping pattern with increased discharge and stream gradient. Empirical orthogonal function (EOF) analysis of high frequency (250Hz) pressure measurements, sampled at an array along the centroid of the flume underneath one wavelength gave further insight into the spatial distribution of turbulent signatures arising from roughness-generated turbulence. A turbulent frequency of 6-10Hz dominates, however the penetration depth appears to

  4. Evaluating two numerical advection schemes in HYCOM for eddy-resolving modelling of the Agulhas Current

    NASA Astrophysics Data System (ADS)

    Backeberg, B. C.; Bertino, L.; Johannessen, J. A.

    2009-06-01

    A 4th order advection scheme is applied in a nested eddy-resolving Hybrid Coordinate Ocean Model (HYCOM) of the greater Agulhas Current system for the purpose of testing advanced numerics as a means for improving the model simulation for eventual operational implementation. Model validation techniques comparing sea surface height variations, sea level skewness and variogram analyses to satellite altimetry measurements quantify that generally the 4th order advection scheme improves the realism of the model simulation. The most striking improvement over the standard 2nd order momentum advection scheme, is that the southern Agulhas Current is simulated as a well-defined meandering current, rather than a train of successive eddies. A better vertical structure and stronger poleward transports in the Agulhas Current core contribute toward a better southwestward penetration of the current, and its temperature field, implying a stronger Indo-Atlantic inter-ocean exchange. It is found that the transport, and hence this exchange, is sensitive to the occurrences of mesoscale features originating upstream in the Mozambique Channel and southern East Madagascar Current, and that the improved HYCOM simulation is well suited for further studies of these inter-actions.

  5. Evaluating two numerical advection schemes in HYCOM for eddy-resolving modelling of the Agulhas Current

    NASA Astrophysics Data System (ADS)

    Backeberg, B. C.; Bertino, L.; Johannessen, J. A.

    2009-02-01

    A 4th order advection scheme is applied in a nested eddy-resolving Hybrid Coordinate Ocean Model (HYCOM) of the greater Agulhas Current system for the purpose of testing advanced numerics as a means for improving the model simulation for eventual operational implementation. Model validation techniques comparing sea surface height variations, sea level skewness and variogram analyses to satellite altimetry measurements quantify that generally the 4th order advection scheme improves the realism of the model simulation. The most striking improvement over the standard 2nd order momentum advection scheme, is that the Southern Agulhas Current is simulated as a well-defined meandering current, rather than a train of successive eddies. A better vertical structure and stronger poleward transports in the Agulhas Current core contribute toward a better southwestward penetration of the current, and its temperature field, implying a stronger Indo-Atlantic inter-ocean exchange. It is found that the transport, and hence this exchange, is sensitive to the occurrences of mesoscale features originating upstream in the Mozambique Channel and Southern East Madagascar Current, and that the improved HYCOM simulation is well suited for further studies of these inter-actions.

  6. Advective turbulent transport in the fluid plasma

    NASA Astrophysics Data System (ADS)

    Min, Byung-Hoon; An, Chan-Yong; Kim, Chang-Bae

    2013-10-01

    The Hasegawa-Wakatani model (HWM) has been employed in pedagogical analyses of the physics behind the behavior of the tokamak plasmas. In addition to the geometric simplicity HWM has an appealing feature of sustaining autonomous quasi-steady state, unstable modes providing the power that is being transported by the nonlinear interactions and is eventually dissipated by the collisional damping at small scales. Emergence of the zonal flow out of the turbulence is a main candidate to cause the transition from the low plasma confinement to the high mode. In the study of such LH transition with the HWM, the adiabaticity parameter has been shown to play an important role in forcing the zonal flow that results in the regulation of the drift-wave turbulence. Instead of concentrating on the physics of the feedback loop between the turbulence and the zonal flow the present study focuses on the presence of the advective transport of the energy. Numerical simulations of HWM are performed and the connections between the advective transport and the zonal flow will be presented. This work was supported by the Supercpmputing Center/Korea Institute of Science and Technology Information with supercomputing resources including technical support (KSC-2013-C1-009).

  7. Advection, diffusion and delivery over a network

    PubMed Central

    Heaton, Luke L.M.; López, Eduardo; Maini, Philip K.; Fricker, Mark D.; Jones, Nick S.

    2014-01-01

    Many biological, geophysical and technological systems involve the transport of resource over a network. In this paper we present an algorithm for calculating the exact concentration of resource at any point in space or time, given that the resource in the network is lost or delivered out of the network at a given rate, while being subject to advection and diffusion. We consider the implications of advection, diffusion and delivery for simple models of glucose delivery through a vascular network, and conclude that in certain circumstances, increasing the volume of blood and the number of glucose transporters can actually decrease the total rate of glucose delivery. We also consider the case of empirically determined fungal networks, and analyze the distribution of resource that emerges as such networks grow over time. Fungal growth involves the expansion of fluid filled vessels, which necessarily involves the movement of fluid. In three empirically determined fungal networks we found that the minimum currents consistent with the observed growth would effectively transport resource throughout the network over the time-scale of growth. This suggests that in foraging fungi, the active transport mechanisms observed in the growing tips may not be required for long range transport. PMID:23005783

  8. Waves, advection, and cloud patterns on Venus

    NASA Technical Reports Server (NTRS)

    Schinder, Paul J.; Gierasch, Peter J.; Leroy, Stephen S.; Smith, Michael D.

    1990-01-01

    The stable layers adjacent to the nearly neutral layer within the Venus clouds are found to be capable of supporting vertically trapped, horizontally propagating waves with horizontal wavelengths of about 10 km and speeds of a few meters per second relative to the mean wind in the neutral layer. These waves may possibly be excited by turbulence within the neutral layer. Here, the properties of the waves, and the patterns which they might produce within the visible clouds if excited near the subsolar point are examined. The patterns can be in agreement with many features in images. The waves are capable of transferring momentum latitudinally to help maintain the general atmospheric spin, but at present we are not able to evaluate wave amplitudes. We also examine an alternative possibility that the cloud patterns are produced by advection and shearing by the mean zonal and meridional flow of blobs formed near the equator. It is concluded that advection and shearing by the mean flow is the most likely explanation for the general pattern of small scale striations.

  9. Upstream waves in Saturn's foreshock

    NASA Technical Reports Server (NTRS)

    Bavassano Cattaneo, M. B.; Cattaneo, P.; Moreno, G.; Lepping, R. P.

    1991-01-01

    An analysis based on plasma and magnetic-field data obtained from Voyager 1 during its Saturn encounter is reported. The plasma data provided every 96 sec and magnetic-field data averaged over 48 sec are utilized. The evidence of upstream waves at Saturn are detected. The waves have a period, in the spacecraft frame, of about 550 sec and a relative amplitude larger than 0.3, are left- and right-hand elliptically polarized, and propagate at about 30 deg with respect to the average magnetic field. The appearance of the waves is correlated with the spacecraft being magnetically connected to the bow shock.

  10. BUOYANT ADVECTION OF GASES IN UNSATURATED SOIL

    PubMed Central

    Seely, Gregory E.; Falta, Ronald W.; Hunt, James R.

    2010-01-01

    In unsaturated soil, methane and volatile organic compounds can significantly alter the density of soil gas and induce buoyant gas flow. A series of laboratory experiments was conducted in a two-dimensional, homogeneous sand pack with gas permeabilities ranging from 110 to 3,000 darcy. Pure methane gas was injected horizontally into the sand and steady-state methane profiles were measured. Experimental results are in close agreement with a numerical model that represents the advective and diffusive components of methane transport. Comparison of simulations with and without gravitational acceleration permits identification of conditions where buoyancy dominates methane transport. Significant buoyant flow requires a Rayleigh number greater than 10 and an injected gas velocity sufficient to overcome dilution by molecular diffusion near the source. These criteria allow the extension of laboratory results to idealized field conditions for methane as well as denser-than-air vapors produced by volatilizing nonaqueous phase liquids trapped in unsaturated soil. PMID:20396624

  11. Thermocouple split follower

    DOEpatents

    Howell, deceased, Louis J.

    1980-01-01

    Thermoelectric generator assembly accommodating differential thermal expansion between thermoelectric elements by means of a cylindrical split follower forming a slot and having internal spring loaded wedges that permit the split follower to open and close across the slot.

  12. Hourly and daily evapotranspiration of alfalfa under regional advection

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Regional advection often affects the evapotranspiration rates of irrigated crops in the Southern High Plains. In 1998, during a 10-day period (13-22 June) of unusually strong advection, high evapotranspiration (ET) rates for unstressed, irrigated alfalfa (Medicago sativa) were measured with two prec...

  13. Advection, diffusion, and delivery over a network

    NASA Astrophysics Data System (ADS)

    Heaton, Luke L. M.; López, Eduardo; Maini, Philip K.; Fricker, Mark D.; Jones, Nick S.

    2012-08-01

    Many biological, geophysical, and technological systems involve the transport of a resource over a network. In this paper, we present an efficient method for calculating the exact quantity of the resource in each part of an arbitrary network, where the resource is lost or delivered out of the network at a given rate, while being subject to advection and diffusion. The key conceptual step is to partition the resource into material that does or does not reach a node over a given time step. As an example application, we consider resource allocation within fungal networks, and analyze the spatial distribution of the resource that emerges as such networks grow over time. Fungal growth involves the expansion of fluid filled vessels, and such growth necessarily involves the movement of fluid. We develop a model of delivery in growing fungal networks, and find good empirical agreement between our model and experimental data gathered using radio-labeled tracers. Our results lead us to suggest that in foraging fungi, growth-induced mass flow is sufficient to account for long-distance transport, if the system is well insulated. We conclude that active transport mechanisms may only be required at the very end of the transport pathway, near the growing tips.

  14. Advective Mechanisms in Tree Island Formation

    NASA Astrophysics Data System (ADS)

    Stothoff, S.

    2002-05-01

    Tree islands are important landscape features in the Florida Everglades. Tres islands are formed of peat deposited on the shallow limestone bedrock, and have been stressed as the system has changed in response to anthropogenic activities due to the sensitivity of organic soils to hydrologic cycles. The plume shape aligned with flow direction for typical tree islands is characteristic of advective transport, despite the rather low flow velocities in the system. Hypothesized mechanisms for the plume shape include sediment transport downstream from the head of the island (often anchored by a bedrock rise), or nutrient transport downstream allowing plants to produce more sediments in situ. Understanding mechanisms controlling tree island shape will aid in understanding the response of tree islands to hydrologic management. An integrated system of field, laboratory, and modeling studies is underway, with the first effort aimed at bounding the importance of the simpler sediment transport processes before tackling more-complex nutrient transport processes. The numerical model integrating the field and laboratory efforts is a 3D finite volume model considering water flow in the shallow groundwater/surface-water system together with sediment transport. The model can account for variable vegetative resistance through the flow column, including the important case where a dense mat forms at the surface. Model components specific for this system and associated data requirements are presented.

  15. Solution of the advection-dispersion equation: Continuous load of finite duration

    USGS Publications Warehouse

    Runkel, R.L.

    1996-01-01

    Field studies of solute fate and transport in streams and rivers often involve an. experimental release of solutes at an upstream boundary for a finite period of time. A review of several standard references on surface-water-quality modeling indicates that the analytical solution to the constant-parameter advection-dispersion equation for this type of boundary condition has been generally overlooked. Here an exact analytical solution that considers a continuous load of unite duration is compared to an approximate analytical solution presented elsewhere. Results indicate that the exact analytical solution should be used for verification of numerical solutions and other solute-transport problems wherein a high level of accuracy is required. ?? ASCE.

  16. Chaotic advection, diffusion, and reactions in open flows

    SciTech Connect

    Tel, Tamas; Karolyi, Gyoergy; Pentek, Aron; Scheuring, Istvan; Toroczkai, Zoltan; Grebogi, Celso; Kadtke, James

    2000-03-01

    We review and generalize recent results on advection of particles in open time-periodic hydrodynamical flows. First, the problem of passive advection is considered, and its fractal and chaotic nature is pointed out. Next, we study the effect of weak molecular diffusion or randomness of the flow. Finally, we investigate the influence of passive advection on chemical or biological activity superimposed on open flows. The nondiffusive approach is shown to carry some features of a weak diffusion, due to the finiteness of the reaction range or reaction velocity. (c) 2000 American Institute of Physics.

  17. Upstream Waves and Particles at the Moon

    NASA Astrophysics Data System (ADS)

    Harada, Y.; Halekas, J. S.

    2016-02-01

    This chapter presents an up-to-date catalog of Moon-related particle populations and lunar upstream waves obtained from in situ measurements at low (<˜100 km) and high altitudes, aimed at organizing and clarifying the currently available information on this complex region, where multiple categories of waves and particles coexist. It then briefly outlines the observed properties of a variety of classes of lunar upstream waves, as well as their generation mechanisms currently proposed, in association with the lunar upstream particle distributions. The lunar upstream region magnetically connected to the Moon and its wake, the fore-moon, represents a remarkably rich zoo of different classes of waves and different types of particles. Although recent observations have substantially enhanced our knowledge by revealing a number of new categories of upstream particles and waves at the Moon, many fundamental questions remain unanswered, and these are outlined in the chapter.

  18. Burgers turbulence and passive random advection

    NASA Astrophysics Data System (ADS)

    Boldyrev, Stanislav Anatolievich

    1999-10-01

    , and the diffusivity is neglected. These considerations illustrate that even with simple statistics of the velocity field, the statistics of advected quantities are nontrivial due to nonlinear interactions of different spatial directions. The last Chapter 5 summarizes the results and discusses future directions of research.

  19. Anomalous scaling of a scalar field advected by turbulence

    SciTech Connect

    Kraichnan, R.H.

    1995-12-31

    Recent work leading to deduction of anomalous scaling exponents for the inertial range of an advected passive field from the equations of motion is reviewed. Implications for other turbulence problems are discussed.

  20. Magnetic helicity transport in the advective gauge family

    SciTech Connect

    Candelaresi, Simon; Brandenburg, Axel; Hubbard, Alexander; Mitra, Dhrubaditya

    2011-01-15

    Magnetic helicity fluxes are investigated in a family of gauges in which the contribution from ideal magnetohydrodynamics takes the form of a purely advective flux. Numerical simulations of magnetohydrodynamic turbulence in this advective gauge family exhibit instabilities triggered by the build-up of unphysical irrotational contributions to the magnetic vector potential. As a remedy, the vector potential is evolved in a numerically well behaved gauge, from which the advective vector potential is obtained by a gauge transformation. In the kinematic regime, the magnetic helicity density evolves similarly to a passive scalar when resistivity is small and turbulent mixing is mild, i.e., when the fluid Reynolds number is not too large. In the dynamical regime, resistive contributions to the magnetic helicity flux in the advective gauge are found to be significant owing to the development of small length scales in the irrotational part of the magnetic vector potential.

  1. Adaptive domain decomposition methods for advection-diffusion problems

    SciTech Connect

    Carlenzoli, C.; Quarteroni, A.

    1995-12-31

    Domain decomposition methods can perform poorly on advection-diffusion equations if diffusion is dominated by advection. Indeed, the hyperpolic part of the equations could affect the behavior of iterative schemes among subdomains slowing down dramatically their rate of convergence. Taking into account the direction of the characteristic lines we introduce suitable adaptive algorithms which are stable with respect to the magnitude of the convective field in the equations and very effective on bear boundary value problems.

  2. Accuracy of tablet splitting.

    PubMed

    McDevitt, J T; Gurst, A H; Chen, Y

    1998-01-01

    We attempted to determine the accuracy of manually splitting hydrochlorothiazide tablets. Ninety-four healthy volunteers each split ten 25-mg hydrochlorothiazide tablets, which were then weighed using an analytical balance. Demographics, grip and pinch strength, digit circumference, and tablet-splitting experience were documented. Subjects were also surveyed regarding their willingness to pay a premium for commercially available, lower-dose tablets. Of 1752 manually split tablet portions, 41.3% deviated from ideal weight by more than 10% and 12.4% deviated by more than 20%. Gender, age, education, and tablet-splitting experience were not predictive of variability. Most subjects (96.8%) stated a preference for commercially produced, lower-dose tablets, and 77.2% were willing to pay more for them. For drugs with steep dose-response curves or narrow therapeutic windows, the differences we recorded could be clinically relevant. PMID:9469693

  3. A spatial SIS model in advective heterogeneous environments

    NASA Astrophysics Data System (ADS)

    Cui, Renhao; Lou, Yuan

    2016-09-01

    We study the effects of diffusion and advection for a susceptible-infected-susceptible epidemic reaction-diffusion model in heterogeneous environments. The definition of the basic reproduction number R0 is given. If R0 < 1, the unique disease-free equilibrium (DFE) is globally asymptotically stable. Asymptotic behaviors of R0 for advection rate and mobility of the infected individuals (denoted by dI) are established, and the existence of the endemic equilibrium when R0 > 1 is studied. The effects of diffusion and advection rates on the stability of the DFE are further investigated. Among other things, we find that if the habitat is a low-risk domain, there may exist one critical value for the advection rate, under which the DFE changes its stability at least twice as dI varies from zero to infinity, while the DFE is unstable for any dI when the advection rate is larger than the critical value. These results are in strong contrast with the case of no advection, where the DFE changes its stability at most once as dI varies from zero to infinity.

  4. Phase mixing versus nonlinear advection in drift-kinetic plasma turbulence

    NASA Astrophysics Data System (ADS)

    Schekochihin, A. A.; Parker, J. T.; Highcock, E. G.; Dellar, P. J.; Dorland, W.; Hammett, G. W.

    2016-04-01

    > A scaling theory of long-wavelength electrostatic turbulence in a magnetised, weakly collisional plasma (e.g. drift-wave turbulence driven by ion temperature gradients) is proposed, with account taken both of the nonlinear advection of the perturbed particle distribution by fluctuating flows and of its phase mixing, which is caused by the streaming of the particles along the mean magnetic field and, in a linear problem, would lead to Landau damping. It is found that it is possible to construct a consistent theory in which very little free energy leaks into high velocity moments of the distribution function, rendering the turbulent cascade in the energetically relevant part of the wavenumber space essentially fluid-like. The velocity-space spectra of free energy expressed in terms of Hermite-moment orders are steep power laws and so the free-energy content of the phase space does not diverge at infinitesimal collisionality (while it does for a linear problem); collisional heating due to long-wavelength perturbations vanishes in this limit (also in contrast with the linear problem, in which it occurs at the finite rate equal to the Landau damping rate). The ability of the free energy to stay in the low velocity moments of the distribution function is facilitated by the `anti-phase-mixing' effect, whose presence in the nonlinear system is due to the stochastic version of the plasma echo (the advecting velocity couples the phase-mixing and anti-phase-mixing perturbations). The partitioning of the wavenumber space between the (energetically dominant) region where this is the case and the region where linear phase mixing wins its competition with nonlinear advection is governed by the `critical balance' between linear and nonlinear time scales (which for high Hermite moments splits into two thresholds, one demarcating the wavenumber region where phase mixing predominates, the other where plasma echo does).

  5. Multi-dimensional upwind fluctuation splitting scheme with mesh adaption for hypersonic viscous flow

    NASA Astrophysics Data System (ADS)

    Wood, William Alfred, III

    A multi-dimensional upwind fluctuation splitting scheme is developed and implemented for two dimensional and axisymmetric formulations of the Navier-Stokes equations on unstructured meshes. Key features of the scheme are the compact stencil, full upwinding, and non-linear discretization which allow for second-order accuracy with enforced positivity. Throughout, the fluctuation splitting scheme is compared to a current state-of-the-art finite volume approach, a second-order, dual mesh upwind flux difference splitting scheme (DMFDSFV), and is shown to produce more accurate results using fewer computer resources for a wide range of test cases. The scalar test cases include advected shear, circular advection, non-linear advection with coalescing shock and expansion fans, and advection-diffusion. For all scalar cases the fluctuation splitting scheme is more accurate, and the primary mechanism for the improved fluctuation splitting performance is shown to be the reduced production of artificial dissipation relative to DMFDSFV. The most significant scalar result is for combined advection-diffusion, where the present fluctuation splitting scheme is able to resolve the physical dissipation from the artificial dissipation on a much coarser mesh than DMFDSFV is able to, allowing order-of-magnitude reductions in solution time. Among the inviscid test cases the converging supersonic streams problem is notable in that the fluctuation splitting scheme exhibits superconvergent third-order spatial accuracy. For the inviscid cases of a supersonic diamond airfoil, supersonic slender cone, and incompressible circular bump the fluctuation splitting drag coefficient errors are typically half the DMFDSFV drag errors. However, for the incompressible inviscid sphere the fluctuation splitting drag error is larger than for DMFDSFV. A Blasius flat plate viscous validation case reveals a more accurate v-velocity profile for fluctuation splitting, and the reduced artificial dissipation

  6. Split-Doa10: a naturally split polytopic eukaryotic membrane protein generated by fission of a nuclear gene.

    PubMed

    Stuerner, Elisabeth; Kuraku, Shigehiro; Hochstrasser, Mark; Kreft, Stefan G

    2012-01-01

    Large polytopic membrane proteins often derive from duplication and fusion of genes for smaller proteins. The reverse process, splitting of a membrane protein by gene fission, is rare and has been studied mainly with artificially split proteins. Fragments of a split membrane protein may associate and reconstitute the function of the larger protein. Most examples of naturally split membrane proteins are from bacteria or eukaryotic organelles, and their exact history is usually poorly understood. Here, we describe a nuclear-encoded split membrane protein, split-Doa10, in the yeast Kluyveromyces lactis. In most species, Doa10 is encoded as a single polypeptide with 12-16 transmembrane helices (TMs), but split-KlDoa10 is encoded as two fragments, with the split occurring between TM2 and TM3. The two fragments assemble into an active ubiquitin-protein ligase. The K. lactis DOA10 locus has two ORFs separated by a 508-bp intervening sequence (IVS). A promoter within the IVS drives expression of the C-terminal KlDoa10 fragment. At least four additional Kluyveromyces species contain an IVS in the DOA10 locus, in contrast to even closely related genera, allowing dating of the fission event to the base of the genus. The upstream Kluyveromyces Doa10 fragment with its N-terminal RING-CH and two TMs resembles many metazoan MARCH (Membrane-Associated RING-CH) and related viral RING-CH proteins, suggesting that gene splitting may have contributed to MARCH enzyme diversification. Split-Doa10 is the first unequivocal case of a split membrane protein where fission occurred in a nuclear-encoded gene. Such a split may allow divergent functions for the individual protein segments. PMID:23071509

  7. High-speed compressible flow and other advection-dominated problems of fluid dynamics

    NASA Technical Reports Server (NTRS)

    Zienkiewicz, O. C.; Lohner, R.; Morgan, K.; Peraire, J.

    1985-01-01

    Finite element methods are described for modeling high speed compressible flows with strong advection, problems important to aerodynamics. The situations are characterized by high pressure and temperature gradients, transients and the appearance of discontinuities, factors which require mesh refinement during computations. Techniques are developed for temporal and spatial discretization of a model problem. Several observations are made regarding the explicit and implicit features of the calculations, the use of the Lax-Wendroff scheme to produce a mass-matrix for obtaining accurate results for transients, methods of performing stability analyses, and simplification techniques. Examples are provided of solving the nonlinear shallow-water equations and describing compressible flows, particularly transonic flows. Domain splitting is defined for improving the calculations at each time step and in different parts of the flow regime while simultaneously advancing the calculations towards a solution.

  8. Experimental tsunami deposits: Linking hydrodynamics to sediment entrainment, advection lengths and downstream fining

    NASA Astrophysics Data System (ADS)

    Johnson, Joel P. L.; Delbecq, Katie; Kim, Wonsuck; Mohrig, David

    2016-01-01

    A goal of paleotsunami research is to quantitatively reconstruct wave hydraulics from sediment deposits in order to better understand coastal hazards. Simple models have been proposed to predict wave heights and velocities, based largely on deposit grain size distributions (GSDs). Although seemingly consistent with some recent tsunamis, little independent data exist to test these equations. We conducted laboratory experiments to evaluate inversion assumptions and uncertainties. A computer-controlled lift gate instantaneously released ~ 6.5 m3 of water into a 32 m flume with shallow ponded water, creating a hydraulic bore that transported sand from an upstream source dune. Differences in initial GSDs and ponded water depths influenced entrainment, transport, and deposition. While the source dune sand was fully suspendable based on size alone, experimental tsunamis produced deposits dominated by bed load sand transport in the upstream ~ 1/3 of the flume and suspension-dominated transport downstream. The suspension deposits exhibited downstream fining and thinning. At 95% confidence, a published advection-settling model predicts time-averaged flow depths to approximately a factor of two, and time-averaged downstream flow velocities to within a factor of 1.5. Finally, reasonable scaling is found between flume and field cases by comparing flow depths, inundation distances, Froude numbers, Rouse numbers and grain size trends in suspension-dominated tsunami deposits, justifying laboratory study of sediment transport and deposition by tsunamis.

  9. UPSTREAM MOTIONS IN STRATIFIED FLOW (JOURNAL VERSION)

    EPA Science Inventory

    In the paper experimental measurements of the time-dependent velocity and density perturbations upstream of obstacles in linearly stratified flow are presented. Attention is concentrated on obstacles which generate turbulent separated wakes at Froude numbers, based on velocity an...

  10. Direct Upstream Motility in Escherichia coli

    PubMed Central

    Kaya, Tolga; Koser, Hur

    2012-01-01

    We provide an experimental demonstration of positive rheotaxis (rapid and continuous upstream motility) in wild-type Escherichia coli freely swimming over a surface. This hydrodynamic phenomenon is dominant below a critical shear rate and robust against Brownian motion and cell tumbling. We deduce that individual bacteria entering a flow system can rapidly migrate upstream (>20 μm/s) much faster than a gradually advancing biofilm. Given a bacterial population with a distribution of sizes and swim speeds, local shear rate near the surface determines the dominant hydrodynamic mode for motility, i.e., circular or random trajectories for low shear rates, positive rheotaxis for moderate flow, and sideways swimming at higher shear rates. Faster swimmers can move upstream more rapidly and at higher shear rates, as expected. Interestingly, we also find on average that both swim speed and upstream motility are independent of cell aspect ratio. PMID:22500751

  11. Splitting a default theory

    SciTech Connect

    Turner, H.

    1996-12-31

    This paper presents mathematical results that can sometimes be used to simplify the task of reasoning about a default theory, by {open_quotes}splitting it into parts.{close_quotes} These so-called Splitting Theorems for default logic are related in spirit to {open_quotes}partial evaluation{close_quotes} in logic programming, in which results obtained from one part of a program are used to simplify the remainder of the program. In this paper we focus primarily on the statement and proof of the Splitting Theorems for default logic. We illustrate the usefulness of the results by applying them to an example default theory for commonsense reasoning about action.

  12. Tablet Splitting: A Risky Practice

    MedlinePlus

    ... and splitting tablets in an effort to save money. Regarding the practice of splitting tablets, the Food ... tablet. So a patient may try to save money by buying the 30 mg tablets and splitting ...

  13. Damping and spectral formation of upstream whistlers

    SciTech Connect

    Orlowski, D.S.; Russell, C.T.; Krauss-Varban, D.

    1995-09-01

    Previous studies have indicated that damping rates of upstream whistlers strongly depend on the details of the electron distribution function. Moreover, detailed analysis of Doppler shift and the whistler dispersion relation indicate that upstream whistlers propagate obliquely in a finite band of frequencies. In this paper we present results of a kinetic calculation of damping lengths of wideband whistlers using the sum of seven drifting bi-Maxwellian electron distributions as a best fit to the ISEE 1 electron data. For two cases, when upstream whistlers are observed, convective damping lengths derived from ISEE magnetic field and ephemeris data are compared with theoretical results. We find that the calculated convective damping lengths are consistent with the data and that upstream whistlers remain marginally stable. We also show that the slope of plasma frame spectra of upstream whistlers, obtained by direct fitting of the observed spectra, is between 5 and 7. The overall spectral, wave, and particle characteristics, proximity to the shock, as well as propagation and damping properties indicated that these waves cannot be generated locally. Instead, the observed upstream whistlers arise in the shock ramp, most likely by a variety of cross-field drift and/or anisotropy driven instabilities. 57 refs., 11 figs.

  14. Concentric Split Flow Filter

    NASA Technical Reports Server (NTRS)

    Stapleton, Thomas J. (Inventor)

    2015-01-01

    A concentric split flow filter may be configured to remove odor and/or bacteria from pumped air used to collect urine and fecal waste products. For instance, filter may be designed to effectively fill the volume that was previously considered wasted surrounding the transport tube of a waste management system. The concentric split flow filter may be configured to split the air flow, with substantially half of the air flow to be treated traveling through a first bed of filter media and substantially the other half of the air flow to be treated traveling through the second bed of filter media. This split flow design reduces the air velocity by 50%. In this way, the pressure drop of filter may be reduced by as much as a factor of 4 as compare to the conventional design.

  15. Polarized Antenna Splitting Functions

    SciTech Connect

    Larkoski, Andrew J.; Peskin, Michael E.; /SLAC

    2009-10-17

    We consider parton showers based on radiation from QCD dipoles or 'antennae'. These showers are built from 2 {yields} 3 parton splitting processes. The question then arises of what functions replace the Altarelli-Parisi splitting functions in this approach. We give a detailed answer to this question, applicable to antenna showers in which partons carry definite helicity, and to both initial- and final-state emissions.

  16. Propagation and damping of broadband upstream whistlers

    NASA Technical Reports Server (NTRS)

    Orlowski, D. S.; Russell, C. T.; Krauss-Varban, D.; Omidi, N.; Thomsen, M. F.

    1995-01-01

    Previous studies indicated that damping rates of upstream whistlers strongly depend on the details of the electron distribution function. Moreover, detailed analysis of Doppler-shift and whistler dispersion relation indicated that upstream whistlers propagate obliquely in a broad band. In this paper we present results of a kinetic calculation of damping lengths of wide-band whistlers using the sum of 7-drifting bi-Maxwellian electron distributions as a best fit to the International Sun Earth Explorer (ISEE) 1 electron data. For 2 cases, when upstream whistlers are observed, convective damping lengths derived from ISEE magnetic field and ephemeris data are compared with theoretical results. We find that the calculated convective damping lengths are consistent with the data and that upstream whistlers remain marginally stable. We also show that the slope of plasma frame spectra of upstream whistlers, obtained by direct fitting of the observed spectra is between 5 and 7 with a sharp lower frequency cutoff corresponding to a wavelength of about one ion inertial length. When the solar wind velocity is directed largely along the wave normal of the upstream whistlers the polariztion of the right hand waves becomes reversed and low frequencies are switched to high resulting in a peaked spectrum with a strong high frequency cutoff. The overall spectral, wave and particle characteristics, proximity to the shock as well as propagation and damping properties indicate that these waves cannot be generated locally. Instead the observed upstream whistlers arise in the shock ramp most likely by a variety of cross-field drift and/or anisotropy driven instabilities.

  17. Advecting Procedural Textures for 2D Flow Animation

    NASA Technical Reports Server (NTRS)

    Kao, David; Pang, Alex; Moran, Pat (Technical Monitor)

    2001-01-01

    This paper proposes the use of specially generated 3D procedural textures for visualizing steady state 2D flow fields. We use the flow field to advect and animate the texture over time. However, using standard texture advection techniques and arbitrary textures will introduce some undesirable effects such as: (a) expanding texture from a critical source point, (b) streaking pattern from the boundary of the flowfield, (c) crowding of advected textures near an attracting spiral or sink, and (d) absent or lack of textures in some regions of the flow. This paper proposes a number of strategies to solve these problems. We demonstrate how the technique works using both synthetic data and computational fluid dynamics data.

  18. Concentration polarization, surface currents, and bulk advection in a microchannel

    NASA Astrophysics Data System (ADS)

    Nielsen, Christoffer P.; Bruus, Henrik

    2014-10-01

    We present a comprehensive analysis of salt transport and overlimiting currents in a microchannel during concentration polarization. We have carried out full numerical simulations of the coupled Poisson-Nernst-Planck-Stokes problem governing the transport and rationalized the behavior of the system. A remarkable outcome of the investigations is the discovery of strong couplings between bulk advection and the surface current; without a surface current, bulk advection is strongly suppressed. The numerical simulations are supplemented by analytical models valid in the long channel limit as well as in the limit of negligible surface charge. By including the effects of diffusion and advection in the diffuse part of the electric double layers, we extend a recently published analytical model of overlimiting current due to surface conduction.

  19. Split-target neutronics and the MLNSC spallation target system

    SciTech Connect

    Russell, G.J.; Ferguson, P.D.; Pitcher, E.J.; Court, J.D.

    1996-12-31

    The Manuel Lujan, Jr., Neutron Scattering Center (MLNSC) at the Los Alamos National Laboratory is one of four operating Short-Pulse Spallation Sources worldwide. The MLNSC target system (composed of targets, moderators, and reflectors) was first installed in 1985. The target system employs a split tungsten spallation target with a void space in between (the flux-trap gap); this target system will be upgraded in 1998. The ability to efficiently split a spallation target allowed us to introduce the concept of flux-trap moderators and ultimately the notion of backscattering and upstream moderators. The upgraded MLNSC target system will employ both flux-trap and upstream/backscattering moderators to simultaneously service 16 neutron flight paths with high-intensity neutron beams for materials science research.

  20. [Sanatoria in Split].

    PubMed

    Kraljević, L; Tomaseo, I

    1990-01-01

    In 1904, the first private surgical sanatorium in the Slavic South was founded in Split by Jaksa Racić, M.D., surgeon, urologist and radiologist. He was conferred degree in Insbruck "sub auspiciis imperatoris" in 1900. The sanatorium had 14 beds, operating theaters for aseptic and septic surgeries, the most modern devices, instruments, roentgenograph and electric light (17 years before Split was supplied with electricity). Doctor Jaksa Racić contributed a lot to the development of Marjan as city-park. All those achievements of Dr. Jaksa Racić were often reported in the Yugoslav and foreign newspapers. Doctor Vladimir Roić opened his own private surgical sanatorium in Split in 1929. His sanatorium had 20 beds, operating theater, delivery room and roentgenograph. In 1933 Dr. Jakov Milicić opened gynecological and obstetric sanatorium in Split. His sanatorium had 15 beds, operating theater, delivery room and roentgenograph. Those three sanatoriums, founded at the beginning of this century, with the first surgical sanatorium of Dr. Jaksa Racić, in 1904, have been of great importance for the development of health services in Split, in general. PMID:2204775

  1. Whistler waves observed upstream from collisionless shocks

    NASA Technical Reports Server (NTRS)

    Fairfield, D. H.

    1973-01-01

    Waves in the frequency range 0.5 - 4 Hz were studied in the region upstream of the earth's bow shock using data from the fluxgate magnetic field experiment on IMP-6. Analysis of 150 examples of these waves during a three month interval indicates that amplitudes are generally less than 1 or 2 gammas and propagation directions generally make angles of between 20 and 40 degrees with the field direction. The waves as measured in the spacecraft frame of reference are either left or right hand polarized with respect to the average field direction. It is concluded that the observed waves are right handed waves in the plasma frame of reference with wavelengths of approximately 100 km propagating upstream in the whistler mode. Doppler shifting reduces the observed frequencies in the spacecraft frame and reverses the observed polarization for those waves propagating more directly upstream. Similar waves are seen ahead of most interplanetary shocks.

  2. Split spline screw

    NASA Technical Reports Server (NTRS)

    Vranish, John M. (Inventor)

    1993-01-01

    A split spline screw type payload fastener assembly, including three identical male and female type split spline sections, is discussed. The male spline sections are formed on the head of a male type spline driver. Each of the split male type spline sections has an outwardly projecting load baring segment including a convex upper surface which is adapted to engage a complementary concave surface of a female spline receptor in the form of a hollow bolt head. Additionally, the male spline section also includes a horizontal spline releasing segment and a spline tightening segment below each load bearing segment. The spline tightening segment consists of a vertical web of constant thickness. The web has at least one flat vertical wall surface which is designed to contact a generally flat vertically extending wall surface tab of the bolt head. Mutual interlocking and unlocking of the male and female splines results upon clockwise and counter clockwise turning of the driver element.

  3. Stabilized Zeeman split laser

    NASA Technical Reports Server (NTRS)

    1981-01-01

    The development of a stablized Zeeman split laser for use in a polarization profilometer is discussed. A Hewlett-Packard laser was modified to stabilize the Zeeman split beat frequency thereby increasing the phase measurement accuracy from the Hewlett-Packard 3 degrees to an accuracy of .01 degrees. The addition of a two layered inductive winding converts the laser to a current controlled oscillator whose frequency is linearly related to coil current. This linear relationship between coil current and laser frequency permits phase locking the laser frequency to a stable crystal controlled reference frequency. The stability of the system is examined and the equipment operation procedures are outlined.

  4. Theory of advection-driven long range biotic transport

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We propose a simple mechanistic model to examine the effects of advective flow on the spread of fungal diseases spread by wind-blown spores. The model is defined by a set of two coupled non-linear partial differential equations for spore densities. One equation describes the long-distance advectiv...

  5. Topology preserving advection of implicit interfaces on Cartesian grids

    NASA Astrophysics Data System (ADS)

    Qin, Zhipeng; Delaney, Keegan; Riaz, Amir; Balaras, Elias

    2015-06-01

    Accurate representation of implicit interface topology is important for the numerical computation of two phase flow on Cartesian grids. A new method is proposed for the construction of signed distance function by geometrically projecting interface topology onto the Cartesian grid using a multi-level projection framework. The method involves a stepwise improvement in the approximation to the signed distance function based on pointwise, piecewise and locally smooth reconstructions of the interface. We show that this approach provides accurate representation of the projected interface and its topology on the Cartesian grid, including the distance from the interface and the interface normal and curvature. The projected interface can be in the form of either a connected set of marker particles that evolve with Lagrangian advection, or a discrete set of points associated with an implicit interface that evolves with the advection of a scalar function. The signed distance function obtained with geometric projection is independent of the details of the scaler field, in contrast to the conventional approach where advection and reinitialization cannot be decoupled. As a result, errors introduced by reinitialization do not amplify advection errors, which leads to substantial improvement in both volume conservation and topology representation.

  6. Consistency problem with tracer advection in the Atmospheric Model GAMIL

    NASA Astrophysics Data System (ADS)

    Zhang, Kai; Wan, Hui; Wang, Bin; Zhang, Meigen

    2008-03-01

    The radon transport test, which is a widely used test case for atmospheric transport models, is carried out to evaluate the tracer advection schemes in the Grid-Point Atmospheric Model of IAP-LASG (GAMIL). Two of the three available schemes in the model are found to be associated with significant biases in the polar regions and in the upper part of the atmosphere, which implies potentially large errors in the simulation of ozone-like tracers. Theoretical analyses show that inconsistency exists between the advection schemes and the discrete continuity equation in the dynamical core of GAMIL and consequently leads to spurious sources and sinks in the tracer transport equation. The impact of this type of inconsistency is demonstrated by idealized tests and identified as the cause of the aforementioned biases. Other potential effects of this inconsistency are also discussed. Results of this study provide some hints for choosing suitable advection schemes in the GAMIL model. At least for the polar-region-concentrated atmospheric components and the closely correlated chemical species, the Flux-Form Semi-Lagrangian advection scheme produces more reasonable simulations of the large-scale transport processes without significantly increasing the computational expense.

  7. ADVECTION INFLUENCES ON EVAPOTRANSPIRATION OF ALFALFA IN A SEMIARID ENVIRONMENT

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Advective enhancement of crop evapotranspiration (ET) occurs when drier, hotter air is transported into the crop by wind and can be an important factor in the water balance of irrigated crops in a semiarid climate. Thirteen days of moderate to extremely high ET rates of irrigated alfalfa (Medicago ...

  8. Tidal variability of lateral advection in a coastal plain estuary

    NASA Astrophysics Data System (ADS)

    Basdurak, N. B.; Valle-Levinson, A.

    2013-07-01

    Tidal variability of lateral advection of momentum (vuy, where u and v are along-estuary and lateral flows, respectively, and the subindex indicates differentiation with respect to the cross-estuary direction) was investigated in a coastal plain estuary with observations at Hampton Roads, which is the transition between the James River and Chesapeake Bay. Towed current velocity profiles and hydrographic profiles were captured during 9 expeditions in 2004 and 2005, to determine the intratidal and spatial changes in lateral advection of momentum and its contribution to along-channel flow. Curvature effects and lateral density gradients were important in driving lateral circulation and in modifying intratidal lateral advection of momentum. Lateral advection had the same order of magnitude as the baroclinic pressure gradient. Its contribution to the along-channel momentum balance was greatest during or just after peak flood and weakest at the end of ebb. During peak flood and peak ebb, the spatial distribution of vuy was seaward at the southern (left) side near surface and at the northern side (right) near bed (looking up-estuary), and landward in the rest of the channel. During slack periods the vuy structures were mostly landward. Observations were in good agreement with analytical model results during peak ebb and flood, but inconsistent during slack periods. The discrepancies between model results and field measurements can be attributed to bathymetry-density gradient interactions, which enhanced ebb-to-flood asymmetries in the along-channel and lateral flow.

  9. Does dispersal control population densities in advection-dominated systems? A fresh look at critical assumptions and a direct test.

    PubMed

    Downes, Barbara J; Lancaster, Jill

    2010-01-01

    1. In advection-dominated systems (both freshwater and marine), population dynamics are usually presumed to be dominated by the effects of migrants dispersing by advection, especially over the small spatial scales at which populations can be studied, but few studies have tested this presumption. We tested the hypothesis that benthic densities are controlled by densities of dispersers for two aquatic insects in upland streams. 2. Our study animals were two species of caddisflies (Hydropsychidae), which become sedentary filter-feeders following settlement onto substrata. Densities of dispersers in the drift (advective dispersal) were quantified using nets placed along the upstream edges of riffles, where the latter abruptly abutted a slower, upstream run. Settlement was estimated at each site using brick pavers, half of which had been fenced to prevent colonization of their top surfaces by walking hydropsychids, thus allowing us to distinguish also the mode of movement during settlement. 3. First through fifth instars of two species, Smicrophylax sp. AV2 and Asmicridea sp. AV1, were abundant and showed disparate results. Drift and settlement were relatively strongly related for Smicrophylax. The best fit lines were shown by second and third instars settling on plain bricks, suggesting that drift played a strong role in settlement, but that some drifters dropped to the bottom and located substrata by walking. Quantile regression suggested that drift sets limits to settlement in this species and that settlement success was highly variable. In contrast, settlement by Asmicridea was poorly related to drift; settlers were mainly individuals re-dispersing within sites. 4. Smicrophylax densities appear to be controlled by dispersal from upstream, but benthic density of Asmicridea is more likely linked to local demography. Our data demonstrate the dangers of assuming that supposedly drift-prone species can all be modelled in the same way. Alternative models emphasizing

  10. The Splitting Group

    ERIC Educational Resources Information Center

    Norton, Anderson; Wilkins, Jesse L. M.

    2012-01-01

    Piagetian theory describes mathematical development as the construction and organization of mental operations within psychological structures. Research on student learning has identified the vital roles of two particular operations--splitting and units coordination--play in students' development of advanced fractions knowledge. Whereas Steffe and…

  11. Splitting of asphaltene species

    SciTech Connect

    Galimov, R.A.; Yusupova, T.N.; Abushaeva, V.V.

    1994-05-10

    The extent of splitting of asphaltene species under the action of solvents correlates with their nature, and primarily with their electron- and proton-donor properties. According to the data of thermal analysis asphaltene species being retained after the action of solvents differ in the weight ratio of peripheral substituents to condensed part and in the fraction of labile bonds. 12 refs., 4 tabs.

  12. Split image optical display

    DOEpatents

    Veligdan, James T.

    2007-05-29

    A video image is displayed from an optical panel by splitting the image into a plurality of image components, and then projecting the image components through corresponding portions of the panel to collectively form the image. Depth of the display is correspondingly reduced.

  13. Split image optical display

    DOEpatents

    Veligdan, James T.

    2005-05-31

    A video image is displayed from an optical panel by splitting the image into a plurality of image components, and then projecting the image components through corresponding portions of the panel to collectively form the image. Depth of the display is correspondingly reduced.

  14. The Splitting Loope

    ERIC Educational Resources Information Center

    Wilkins, Jesse L. M.; Norton, Anderson

    2011-01-01

    Teaching experiments have generated several hypotheses concerning the construction of fraction schemes and operations and relationships among them. In particular, researchers have hypothesized that children's construction of splitting operations is crucial to their construction of more advanced fractions concepts (Steffe, 2002). The authors…

  15. (O)Mega split

    NASA Astrophysics Data System (ADS)

    Benakli, Karim; Darmé, Luc; Goodsell, Mark D.

    2015-11-01

    We study two realisations of the Fake Split Supersymmetry Model (FSSM), the simplest model that can easily reproduce the experimental value of the Higgs mass for an arbitrarily high supersymmetry scale M S , as a consequence of swapping higgsinos for equivalent states, fake higgsinos, with suppressed Yukawa couplings. If the LSP is identified as the main Dark matter component, then a standard thermal history of the Universe implies upper bounds on M S , which we derive. On the other hand, we show that renormalisation group running of soft masses above M S barely constrains the model — in stark contrast to Split Supersymmetry — and hence we can have a "Mega Split" spectrum even with all of these assumptions and constraints, which include the requirements of a correct relic abundance, a gluino life-time compatible with Big Bang Nucleosynthesis and absence of signals in present direct detection experiments of inelastic dark matter. In an appendix we describe a related scenario, Fake Split Extended Supersymmetry, which enjoys similar properties.

  16. On the error propagation of semi-Lagrange and Fourier methods for advection problems☆

    PubMed Central

    Einkemmer, Lukas; Ostermann, Alexander

    2015-01-01

    In this paper we study the error propagation of numerical schemes for the advection equation in the case where high precision is desired. The numerical methods considered are based on the fast Fourier transform, polynomial interpolation (semi-Lagrangian methods using a Lagrange or spline interpolation), and a discontinuous Galerkin semi-Lagrangian approach (which is conservative and has to store more than a single value per cell). We demonstrate, by carrying out numerical experiments, that the worst case error estimates given in the literature provide a good explanation for the error propagation of the interpolation-based semi-Lagrangian methods. For the discontinuous Galerkin semi-Lagrangian method, however, we find that the characteristic property of semi-Lagrangian error estimates (namely the fact that the error increases proportionally to the number of time steps) is not observed. We provide an explanation for this behavior and conduct numerical simulations that corroborate the different qualitative features of the error in the two respective types of semi-Lagrangian methods. The method based on the fast Fourier transform is exact but, due to round-off errors, susceptible to a linear increase of the error in the number of time steps. We show how to modify the Cooley–Tukey algorithm in order to obtain an error growth that is proportional to the square root of the number of time steps. Finally, we show, for a simple model, that our conclusions hold true if the advection solver is used as part of a splitting scheme. PMID:25844018

  17. Aerosol particles and the formation of advection fog

    NASA Technical Reports Server (NTRS)

    Hung, R. J.; Liaw, G. S.; Vaughan, O. H., Jr.

    1979-01-01

    A study of numerical simulation of the effects of concentration, particle size, mass of nuclei, and chemical composition on the dynamics of warm fog formation, particularly the formation of advection fog, is presented. This formation is associated with the aerosol particle characteristics, and both macrophysical and microphysical processes are considered. In the macrophysical model, the evolution of wind components, water vapor content, liquid water content, and potential temperature under the influences of vertical turbulent diffusion, turbulent momentum, and turbulent energy transfers are taken into account. In the microphysical model, the supersaturation effect is incorporated with the surface tension and hygroscopic material solution. It is shown that the aerosol particles with the higher number density, larger size nuclei, the heavier nuclei mass, and the higher ratio of the Van't Hoff factor to the molecular weight favor the formation of the lower visibility advection fogs with stronger vertical energy transfer during the nucleation and condensation time period.

  18. Spiral defect chaos in an advection-reaction-diffusion system

    NASA Astrophysics Data System (ADS)

    Affan, H.; Friedrich, R.

    2014-06-01

    This paper comprises numerical and theoretical studies of spatiotemporal patterns in advection-reaction-diffusion systems in which the chemical species interact with the hydrodynamic fluid. Due to the interplay between the two, we obtained the spiral defect chaos in the activator-inhibitor-type model. We formulated the generalized Swift-Hohenberg-type model for this system. Then the evolution of fractal boundaries due to the effect of the strong nonlinearity at the interface of the two chemical species is studied numerically. The purpose of the present paper is to point out that spiral defect chaos, observed in model equations of the extended Swift-Hohenberg equation for low Prandtl number convection, may actually be obtained also in certain advection-reaction-diffusion systems.

  19. Phase Segregation of Passive Advective Particles in an Active Medium.

    PubMed

    Das, Amit; Polley, Anirban; Rao, Madan

    2016-02-12

    Localized contractile configurations or asters spontaneously appear and disappear as emergent structures in the collective stochastic dynamics of active polar actomyosin filaments. Passive particles which (un)bind to the active filaments get advected into the asters, forming transient clusters. We study the phase segregation of such passive advective scalars in a medium of dynamic asters, as a function of the aster density and the ratio of the rates of aster remodeling to particle diffusion. The dynamics of coarsening shows a violation of Porod behavior; the growing domains have diffuse interfaces and low interfacial tension. The phase-segregated steady state shows strong macroscopic fluctuations characterized by multiscaling and intermittency, signifying rapid reorganization of macroscopic structures. We expect these unique nonequilibrium features to manifest in the actin-dependent molecular clustering at the cell surface. PMID:26919022

  20. Phase Segregation of Passive Advective Particles in an Active Medium

    NASA Astrophysics Data System (ADS)

    Das, Amit; Polley, Anirban; Rao, Madan

    2016-02-01

    Localized contractile configurations or asters spontaneously appear and disappear as emergent structures in the collective stochastic dynamics of active polar actomyosin filaments. Passive particles which (un)bind to the active filaments get advected into the asters, forming transient clusters. We study the phase segregation of such passive advective scalars in a medium of dynamic asters, as a function of the aster density and the ratio of the rates of aster remodeling to particle diffusion. The dynamics of coarsening shows a violation of Porod behavior; the growing domains have diffuse interfaces and low interfacial tension. The phase-segregated steady state shows strong macroscopic fluctuations characterized by multiscaling and intermittency, signifying rapid reorganization of macroscopic structures. We expect these unique nonequilibrium features to manifest in the actin-dependent molecular clustering at the cell surface.

  1. High time resolution studies of upstream ions

    NASA Technical Reports Server (NTRS)

    Anderson, K. A.; Levedahl, W. K.; Lin, R. P.; Parks, G. K.

    1984-01-01

    The influence of phi, the angle between the interplanetary magnetic field and the earth-sun vector on ions and electrons in the earth's bow shock, was investigated in terms of ISEE 2 data. A small phi was associated with intermediate energy upstream ions and reduced populations of low energy, about 1.6 keV, ion fluxes. The magnitude of phi was closely related to particular, constant energy levels, e.g., a phi of 40 deg and an energy of 30 keV and a phi of 75 deg and an energy of 6 keV. Ion fluxes are high in the angles form 60-80 deg and feature energies of 55-280 keV. The acceleration process up to the high energy levels in the 1-3 min interval from upstream to downstream occurs more rapidly than could be accounted for by a first-order Fermi process.

  2. Bilateral Sagittal Split Osteotomy

    PubMed Central

    Monson, Laura A.

    2013-01-01

    The bilateral sagittal split osteotomy is an indispensable tool in the correction of dentofacial abnormalities. The technique has been in practice since the late 1800s, but did not reach widespread acceptance and use until several modifications were described in the 1960s and 1970s. Those modifications came from a desire to make the procedure safer, more reliable, and more predictable with less relapse. Those goals continue to stimulate innovation in the field today and have helped the procedure evolve to be a very dependable, consistent method of correction of many types of malocclusion. The operative surgeon should be well versed in the history, anatomy, technical aspects, and complications of the bilateral sagittal split osteotomy to fully understand the procedure and to counsel the patient. PMID:24872760

  3. Fee splitting in ophthalmology.

    PubMed

    Levin, Alex V; Ganesh, Anuradha; Al-Busaidi, Ahmed

    2011-02-01

    Fee splitting and co-management are common practices in ophthalmology. These arrangements may conflict with the ethical principles governing the doctor-patient relationship, may constitute professional misconduct, and at times, may be illegal. Implications and perceptions of these practices may vary between different cultures. Full disclosure to the patient may minimize the adverse effects of conflicts of interest that arise from these practices, and may thereby allow these practices to be deemed acceptable by some cultural morays, professional guidelines, or by law. Disclosure does not necessarily relieve the physician from a potential ethical compromise. This review examines the practice of fee splitting in ophthalmology, its legal implications, the policies or guidelines governing such arrangements, and the possible ethical ramifications. A comparative view between 3 countries, Canada, the United States, and Oman, was conducted; illustrating that even in disparate cultures, there may be some universality to the application of ethical principles. PMID:21283153

  4. Splitting water with cobalt.

    PubMed

    Artero, Vincent; Chavarot-Kerlidou, Murielle; Fontecave, Marc

    2011-08-01

    The future of energy supply depends on innovative breakthroughs regarding the design of cheap, sustainable, and efficient systems for the conversion and storage of renewable energy sources, such as solar energy. The production of hydrogen, a fuel with remarkable properties, through sunlight-driven water splitting appears to be a promising and appealing solution. While the active sites of enzymes involved in the overall water-splitting process in natural systems, namely hydrogenases and photosystem II, use iron, nickel, and manganese ions, cobalt has emerged in the past five years as the most versatile non-noble metal for the development of synthetic H(2)- and O(2)-evolving catalysts. Such catalysts can be further coupled with photosensitizers to generate photocatalytic systems for light-induced hydrogen evolution from water. PMID:21748828

  5. Upgrade of the Upstream Tracker at LHCb

    NASA Astrophysics Data System (ADS)

    Andrews, Jason; LHCb Collaboration

    2015-04-01

    The LHCb detector will be upgraded to allow it operate at higher collider luminosity without the need for a hardware trigger stage. Flavor enriched events will be selected in a software based, high level trigger, using fully reconstructed events. This presentation will describe the design, optimization and the expected performance of the Upstream Tracker (UT), which has a critical role in high level trigger scheme.

  6. Admissible upstream conditions for slender compressible vortices

    NASA Technical Reports Server (NTRS)

    Liu, C. H.; Krause, E.; Menne, S.

    1986-01-01

    The influence of the compressibility on the flow in slender vortices is being studied. The dependence of the breakdown of the slender-vortex approximation on the upstream conditions is demonstrated for various Reynolds numbers and Mach numbers. Compatibility conditions, which have to be satisfied if the vortex is to remain slender, are discussed in detail. The general discussions are supplemented by several sample calculations.

  7. Lattice Boltzmann method for the fractional advection-diffusion equation

    NASA Astrophysics Data System (ADS)

    Zhou, J. G.; Haygarth, P. M.; Withers, P. J. A.; Macleod, C. J. A.; Falloon, P. D.; Beven, K. J.; Ockenden, M. C.; Forber, K. J.; Hollaway, M. J.; Evans, R.; Collins, A. L.; Hiscock, K. M.; Wearing, C.; Kahana, R.; Villamizar Velez, M. L.

    2016-04-01

    Mass transport, such as movement of phosphorus in soils and solutes in rivers, is a natural phenomenon and its study plays an important role in science and engineering. It is found that there are numerous practical diffusion phenomena that do not obey the classical advection-diffusion equation (ADE). Such diffusion is called abnormal or superdiffusion, and it is well described using a fractional advection-diffusion equation (FADE). The FADE finds a wide range of applications in various areas with great potential for studying complex mass transport in real hydrological systems. However, solution to the FADE is difficult, and the existing numerical methods are complicated and inefficient. In this study, a fresh lattice Boltzmann method is developed for solving the fractional advection-diffusion equation (LabFADE). The FADE is transformed into an equation similar to an advection-diffusion equation and solved using the lattice Boltzmann method. The LabFADE has all the advantages of the conventional lattice Boltzmann method and avoids a complex solution procedure, unlike other existing numerical methods. The method has been validated through simulations of several benchmark tests: a point-source diffusion, a boundary-value problem of steady diffusion, and an initial-boundary-value problem of unsteady diffusion with the coexistence of source and sink terms. In addition, by including the effects of the skewness β , the fractional order α , and the single relaxation time τ , the accuracy and convergence of the method have been assessed. The numerical predictions are compared with the analytical solutions, and they indicate that the method is second-order accurate. The method presented will allow the FADE to be more widely applied to complex mass transport problems in science and engineering.

  8. Advective and diffusive cosmic ray transport in galactic haloes

    NASA Astrophysics Data System (ADS)

    Heesen, Volker; Dettmar, Ralf-Jürgen; Krause, Marita; Beck, Rainer; Stein, Yelena

    2016-05-01

    We present 1D cosmic ray transport models, numerically solving equations of pure advection and diffusion for the electrons and calculating synchrotron emission spectra. We find that for exponential halo magnetic field distributions advection leads to approximately exponential radio continuum intensity profiles, whereas diffusion leads to profiles that can be better approximated by a Gaussian function. Accordingly, the vertical radio spectral profiles for advection are approximately linear, whereas for diffusion they are of `parabolic' shape. We compare our models with deep Australia Telescope Compact Array observations of two edge-on galaxies, NGC 7090 and 7462, at λλ 22 and 6 cm. Our result is that the cosmic ray transport in NGC 7090 is advection dominated with V=150^{+80}_{-30} km s^{-1}, and that the one in NGC 7462 is diffusion dominated with D=3.0± 1.0 × 10^{28}E_GeV^{0.5} cm^2 s^{-1}. NGC 7090 has both a thin and thick radio disc with respective magnetic field scale heights of hB1 = 0.8 ± 0.1 kpc and hB2 = 4.7 ± 1.0 kpc. NGC 7462 has only a thick radio disc with hB2 = 3.8 ± 1.0 kpc. In both galaxies, the magnetic field scale heights are significantly smaller than what estimates from energy equipartition would suggest. A non-negligible fraction of cosmic ray electrons can escape from NGC 7090, so that this galaxy is not an electron calorimeter.

  9. Lattice Boltzmann method for the fractional advection-diffusion equation.

    PubMed

    Zhou, J G; Haygarth, P M; Withers, P J A; Macleod, C J A; Falloon, P D; Beven, K J; Ockenden, M C; Forber, K J; Hollaway, M J; Evans, R; Collins, A L; Hiscock, K M; Wearing, C; Kahana, R; Villamizar Velez, M L

    2016-04-01

    Mass transport, such as movement of phosphorus in soils and solutes in rivers, is a natural phenomenon and its study plays an important role in science and engineering. It is found that there are numerous practical diffusion phenomena that do not obey the classical advection-diffusion equation (ADE). Such diffusion is called abnormal or superdiffusion, and it is well described using a fractional advection-diffusion equation (FADE). The FADE finds a wide range of applications in various areas with great potential for studying complex mass transport in real hydrological systems. However, solution to the FADE is difficult, and the existing numerical methods are complicated and inefficient. In this study, a fresh lattice Boltzmann method is developed for solving the fractional advection-diffusion equation (LabFADE). The FADE is transformed into an equation similar to an advection-diffusion equation and solved using the lattice Boltzmann method. The LabFADE has all the advantages of the conventional lattice Boltzmann method and avoids a complex solution procedure, unlike other existing numerical methods. The method has been validated through simulations of several benchmark tests: a point-source diffusion, a boundary-value problem of steady diffusion, and an initial-boundary-value problem of unsteady diffusion with the coexistence of source and sink terms. In addition, by including the effects of the skewness β, the fractional order α, and the single relaxation time τ, the accuracy and convergence of the method have been assessed. The numerical predictions are compared with the analytical solutions, and they indicate that the method is second-order accurate. The method presented will allow the FADE to be more widely applied to complex mass transport problems in science and engineering. PMID:27176431

  10. Anomalous diffusion of a tracer advected by wave turbulence

    NASA Astrophysics Data System (ADS)

    Balk, Alexander M.

    2001-02-01

    We consider the advection of a passive tracer when the velocity field is a superposition of random waves. Green's function for the turbulent transport (turbulent diffusion and turbulent drift) is derived. This Green's function is shown to imply sub-diffusive or super-diffusive behavior of the tracer. For the analysis we introduce the statistical near-identity transformation. The results are confirmed by numerical simulations.

  11. Cellwise conservative unsplit advection for the volume of fluid method

    NASA Astrophysics Data System (ADS)

    Comminal, Raphaël; Spangenberg, Jon; Hattel, Jesper Henri

    2015-02-01

    We present a cellwise conservative unsplit (CCU) advection scheme for the volume of fluid method (VOF) in 2D. Contrary to other schemes based on explicit calculations of the flux balances, the CCU advection adopts a cellwise approach where the pre-images of the control volumes are traced backwards through the flow map. The donating regions of the fluxes are calculated via the streaklines of the grid intersections, represented as polygonal chains whose vertices are determined by backward tracing of particles injected in the flow at different times. High order accuracy is obtained from the fourth-order Runge-Kutta method, where intermediate velocities along pathlines are determined with quadratic temporal and bicubic spatial interpolations. The volumes of the donating regions are corrected in order to fulfill the discrete continuity of incompressible flows. Consequently, the calculation produces non-overlapping donating regions and pre-images with conforming edges to their neighbors, resulting in the conservativeness and the boundedness (liquid volume fraction inside the interval [ 0 , 1 ]) of the CCU advection scheme. Finally, the update of the liquid volume fractions is computed from the intersections of the pre-image polygons with the reconstructed interfaces. The CCU scheme is tested on several benchmark tests for the VOF advection, together with the standard piecewise linear interface calculation (PLIC). The geometrical errors of the CCU compare favorably with other unsplit VOF-PLIC schemes. Finally, potential improvements of the VOF method with the use of more precise interface representation techniques and the future extension of the CCU scheme to 3D are discussed.

  12. TUBE SPLITTING APPARATUS

    DOEpatents

    Frantz, C.E.; Cawley, W.E.

    1961-05-01

    A tool is described for cutting a coolant tube adapted to contain fuel elements to enable the tube to be removed from a graphite moderator mass. The tool splits the tube longitudinally into halves and curls the longitudinal edges of the halves inwardly so that they occupy less space and can be moved radially inwardly away from the walls of the hole in the graphite for easy removal from the graphite.

  13. Development of new flux splitting schemes. [computational fluid dynamics algorithms

    NASA Technical Reports Server (NTRS)

    Liou, Meng-Sing; Steffen, Christopher J., Jr.

    1992-01-01

    Maximizing both accuracy and efficiency has been the primary objective in designing a numerical algorithm for computational fluid dynamics (CFD). This is especially important for solutions of complex three dimensional systems of Navier-Stokes equations which often include turbulence modeling and chemistry effects. Recently, upwind schemes have been well received for their capability in resolving discontinuities. With this in mind, presented are two new flux splitting techniques for upwind differencing. The first method is based on High-Order Polynomial Expansions (HOPE) of the mass flux vector. The second new flux splitting is based on the Advection Upwind Splitting Method (AUSM). The calculation of the hypersonic conical flow demonstrates the accuracy of the splitting in resolving the flow in the presence of strong gradients. A second series of tests involving the two dimensional inviscid flow over a NACA 0012 airfoil demonstrates the ability of the AUSM to resolve the shock discontinuity at transonic speed. A third case calculates a series of supersonic flows over a circular cylinder. Finally, the fourth case deals with tests of a two dimensional shock wave/boundary layer interaction.

  14. Modeling solute advection coupled with sorption kinetics in heterogeneous formations

    NASA Astrophysics Data System (ADS)

    Selroos, Jan-Olof; Cvetkovic, Vladimir

    1992-05-01

    A method for coupling sorption kinetics and solute advection in particle-tracking models is proposed; this method is efficient for the case where sorption rate coefficients can be assumed constant field scale parameters. A simulation example of reactive solute advection in two-dimensional heterogeneous porous media is presented. The effect of sorption kinetics on solute advection is investigated. Nonequilibrium effects are exhibited as enhanced tailing in the solute breakthrough. Because high variability in the hydraulic conductivity also yields enhanced tailing, the nonequilibrium effect is more pronounced for the case of low variability. Moreover, it may be difficult to distinguish cases of low variability with nonequilibrium sorption from cases of high variability with equilibrium sorption. A comparison of Monte Carlo ensemble results is made with an analytical model for the mass arrival of kinetically sorbing solute in heterogeneous porous media obtained using first-order perturbation. The comparison indicates that the analytical model provides reasonable approximations of the expected solute breakthrough if the variance of the natural logarithm of the hydraulic conductivity is smaller than 1.

  15. Super-diffusion versus competitive advection: a simulation

    NASA Astrophysics Data System (ADS)

    Del Moro, D.; Giannattasio, F.; Berrilli, F.; Consolini, G.; Lepreti, F.; Gošić, M.

    2015-04-01

    Context. Magnetic element tracking is often used to study the transport and diffusion of the magnetic field on the solar photosphere. From the analysis of the displacement spectrum of these tracers, it has recently been agreed that a regime of super-diffusivity dominates the solar surface. Quite habitually this result is discussed in the framework of fully developed turbulence. Aims: However, the debate whether the super-diffusivity is generated by a turbulent dispersion process, by the advection due to the convective pattern, or even by another process is still open, as is the question of the amount of diffusivity at the scales relevant to the local dynamo process. Methods: To understand how such peculiar diffusion in the solar atmosphere takes place, we compared the results from two different data sets (ground-based and space-borne) and developed a simulation of passive tracers advection by the deformation of a Voronoi network. Results: The displacement spectra of the magnetic elements obtained by the data sets are consistent in retrieving a super-diffusive regime for the solar photosphere, but the simulation also shows a super-diffusive displacement spectrum: its competitive advection process can reproduce the signature of super-diffusion. Conclusions: Therefore, it is not necessary to hypothesize a totally developed turbulence regime to explain the motion of the magnetic elements on the solar surface.

  16. Vertical Structure of Advection-dominated Accretion Flows

    NASA Astrophysics Data System (ADS)

    Zahra Zeraatgari, Fateme; Abbassi, Shahram

    2015-08-01

    We solve the set of hydrodynamic equations for optically thin advection-dominated accretion flows by assuming a radially self-similar spherical coordinate system (r,θ ,φ ). The disk is considered to be in steady state and axisymmetric. We define the boundary conditions at the pole and the equator of the disk and, to avoid singularity at the rotation axis, the disk is taken to be symmetric with respect to this axis. Moreover, only the {τ }rφ component of the viscous stress tensor is assumed, and we have set {v}θ =0. The main purpose of this study is to investigate the variation of dynamical quantities of the flow in the vertical direction by finding an analytical solution. As a consequence, we found that the advection parameter, {f}{adv}, varies along the θ direction and reaches its maximum near the rotation axis. Our results also show that, in terms of the no-outflow solution, thermal equilibrium still exists and consequently advection cooling can balance viscous heating.

  17. Laser speckle contrast imaging is sensitive to advective flux

    NASA Astrophysics Data System (ADS)

    Khaksari, Kosar; Kirkpatrick, Sean J.

    2016-07-01

    Unlike laser Doppler flowmetry, there has yet to be presented a clear description of the physical variables that laser speckle contrast imaging (LSCI) is sensitive to. Herein, we present a theoretical basis for demonstrating that LSCI is sensitive to total flux and, in particular, the summation of diffusive flux and advective flux. We view LSCI from the perspective of mass transport and briefly derive the diffusion with drift equation in terms of an LSCI experiment. This equation reveals the relative sensitivity of LSCI to both diffusive flux and advective flux and, thereby, to both concentration and the ordered velocity of the scattering particles. We demonstrate this dependence through a short series of flow experiments that yield relationships between the calculated speckle contrast and the concentration of the scatterers (manifesting as changes in scattering coefficient), between speckle contrast and the velocity of the scattering fluid, and ultimately between speckle contrast and advective flux. Finally, we argue that the diffusion with drift equation can be used to support both Lorentzian and Gaussian correlation models that relate observed contrast to the movement of the scattering particles and that a weighted linear combination of these two models is likely the most appropriate model for relating speckle contrast to particle motion.

  18. Distinguishing resuspension and advection signals in a hypertidal estuary

    NASA Astrophysics Data System (ADS)

    Todd, David; Souza, Alex; Jago, Colin

    2015-04-01

    Terrestrial material is supplied to an estuary system by the river, while marine material is supplied by the sea. Whether the estuary acts as a trap or a bypass zone for SPM (suspended particulate matter) depends upon the properties and dynamics of both the estuary, including the tidal and residual behaviour of the currents, and the SPM, including particle sizes and settling velocities and concentration gradients, which together control the dynamics, such as the trapping efficiency, of the estuary. Whether an SPM signal is regarded as being one of resuspension or advection depends upon the area of interest, and therefore distinguishing between resuspension and advection can be complex. Material that is resuspended within the area of study is regarded as resuspension, while that which is resuspended outside, but passes through, the area of interest, is regarded as advection. The results of a measurement campaign undertaken in a hypertidal UK estuary during the pre-spring bloom February-March and post-spring bloom May-June are presented utilising a combination of acoustic and optical instruments, moorings, and CTD stations. A characteristic asymmetric "twin peak" signal is present during both time periods, implying the presence of both resuspension and advection. This is confirmed through the use of harmonic analysis. A seasonal variation in the relative importance of the resuspension and advection components is seen between the two observation periods, with the small (<122µm) and large (>122µm) particles displaying different behaviours and providing a strong indication of the presence of flocculation. Approximate point flux calculations showed a reduction in the horizontal gradient of concentration, and subsequently the flood dominance of sediment transport, between May-June and February-March. This has been attributed to changes in biological activity and atmospheric forcing between the two observational periods. Ebb-dominant concentrations brought about by the

  19. Horizontal Advection and Mixing of Pollutants in the Urban Atmospheric Environment

    NASA Astrophysics Data System (ADS)

    Magnusson, S. P.; Entekhabi, D.; Britter, R.; Norford, L.; Fernando, H. J.

    2013-12-01

    Although urban air quality and its impacts on the public health have long been studied, the increasing urbanization is raising concerns on how to better control and mitigate these health impacts. A necessary element in predicting exposure levels is fundamental understanding of flow and dispersion in urban canyons. The complex topology of building structures and roads requires the resolution of turbulence phenomena within urban canyons. The use of dense and low porosity construction material can lead to rapid heating in response to direct solar exposure due to large thermal mass. Hence thermal and buoyancy effects may be as important as mechanically-forced or shear-induced flows. In this study, the transport of pollutants within the urban environment, as well as the thermal and advection effects, are investigated. The focus is on the horizontal transport or the advection effects within the urban environment. With increased urbanization and larger and more spread cities, concern about how the upstream air quality situation can affect downstream areas. The study also examines the release and the dispersion of hazardous material. Due to the variety and complexity of urban areas around the world, the urban environment is simplified into adjacent two-dimensional urban street canyons. Pollutants are released inside each canyon. Computational Fluid Dynamics (CFD) simulations are applied to evaluate and quantify the flow rate out of each canyon and also the exchange of pollutants between the canyons. Imagine a row of ten adjacent urban street canyons of aspect ratio 1 with horizontal flow perpendicular to it as shown in the attached figure. C is the concentration of pollutants. The first digit indicates in what canyon the pollutant is released and the second digit indicates the location of that pollutant. For example, C3,4 is the concentration of pollutant released inside canyon 3 measured in canyon 4. The same amount of pollution is released inside the ten street canyons

  20. The nature and role of advection in advection-diffusion equations used for modelling bed load transport

    NASA Astrophysics Data System (ADS)

    Ancey, Christophe; Bohorquez, Patricio; Heyman, Joris

    2016-04-01

    The advection-diffusion equation arises quite often in the context of sediment transport, e.g., for describing time and space variations in the particle activity (the solid volume of particles in motion per unit streambed area). Stochastic models can also be used to derive this equation, with the significant advantage that they provide information on the statistical properties of particle activity. Stochastic models are quite useful when sediment transport exhibits large fluctuations (typically at low transport rates), making the measurement of mean values difficult. We develop an approach based on birth-death Markov processes, which involves monitoring the evolution of the number of particles moving within an array of cells of finite length. While the topic has been explored in detail for diffusion-reaction systems, the treatment of advection has received little attention. We show that particle advection produces nonlocal effects, which are more or less significant depending on the cell size and particle velocity. Albeit nonlocal, these effects look like (local) diffusion and add to the intrinsic particle diffusion (dispersal due to velocity fluctuations), with the important consequence that local measurements depend on both the intrinsic properties of particle displacement and the dimensions of the measurement system.

  1. ROTATIONAL SPLITTING OF PULSATION MODES

    SciTech Connect

    Deupree, Robert G.; Beslin, Wilfried

    2010-10-01

    Mode splittings produced by uniform rotation and a particular form of differential rotation are computed for two-dimensional rotating 10 M{sub sun} zero-age main sequence stellar models. The change in the character of the mode splitting is traced as a function of uniform rotation rate, and it is found that only relatively slow rotation rates are required before the mode splitting becomes asymmetric about the azimuthally symmetric (m = 0) mode. Increased rotation produces a progressively altered pattern of the individual modes with respect to each other. Large mode splittings begin to overlap with the mode splittings produced by different radial and latitudinal modes at relatively low rotation rates. The mode-splitting pattern for the differentially rotating stars we model is different than that for uniformly rotating stars, making the mode splitting a possible discriminant of the internal angular momentum distribution if one assumes that the formidable challenge of mode identification can be overcome.

  2. 8. GENERAL EXTERIOR VIEW LOOKING SOUTH, SHOWING UPSTREAM FACE OF ...

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

    8. GENERAL EXTERIOR VIEW LOOKING SOUTH, SHOWING UPSTREAM FACE OF DAM/SPILLWAY; THE VIEW HIGHLIGHTS THE UPSTREAM APPEARANCE OF THE PIERS SUPPORTING THE MOVABLE STONEY GATES. - Bonneville Project, Bonneville Dam, Columbia River, Bonneville, Multnomah County, OR

  3. Upstream waves at Mars - Phobos observations

    NASA Technical Reports Server (NTRS)

    Russell, C. T.; Luhmann, J. G.; Schwingenschuh, K.; Riedler, W.; Eroshenko, E.

    1990-01-01

    The region upstream from the Mars subsolar bow shock is surveyed for the presence of MHD wave phenomena using the high temporal resolution data from the Magma magnetometer. Strong turbulence is observed when the magnetic field is connected to the Mars bow shock in such a way as to allow diffuse ions to reach the spacecraft. Also weak waves are observed at the proton gyro frequency. These waves are left-hand elliptically polarized and may be associated with the pick-up of protons from the Mars hydrogen exosphere.

  4. Splitting the Cartesian point

    SciTech Connect

    Blodwell, J.F.

    1987-10-01

    It is argued that the point structure of space and time must be constructed from the primitive extensional character of space and time. A procedure for doing this is laid down and applied to one-dimensional and two-dimensional systems of abstract extensions. Topological and metrical properties of the constructed point systems, which differ nontrivially from the usual R and R/sup 2/ models, are examined. Briefly, constructed points are associated with directions and the Cartesian point is split. In one-dimension each point splits into a point pair compatible with the linear ordering. An application to one-dimensional particle motion is given, with the result that natural topological assumptions force the number of left point, right point transitions to remain locally finite in a continuous motion. In general, Cartesian points are seen to correspond to certain filters on a suitable Boolean algebra. Constructed points correspond to ultrafilters. Thus, point construction gives a natural refinement of the Cartesian systems.

  5. Update on Advection-Diffusion Purge Flow Model

    NASA Technical Reports Server (NTRS)

    Brieda, Lubos

    2015-01-01

    Gaseous purge is commonly used in sensitive spacecraft optical or electronic instruments to prevent infiltration of contaminants and/or water vapor. Typically, purge is sized using simplistic zero-dimensional models that do not take into account instrument geometry, surface effects, and the dependence of diffusive flux on the concentration gradient. For this reason, an axisymmetric computational fluid dynamics (CFD) simulation was recently developed to model contaminant infiltration and removal by purge. The solver uses a combined Navier-Stokes and Advection-Diffusion approach. In this talk, we report on updates in the model, namely inclusion of a particulate transport model.

  6. Numerical simulation of life cycles of advection warm fog

    NASA Technical Reports Server (NTRS)

    Hung, R. J.; Vaughan, O. H.

    1977-01-01

    The formation, development and dissipation of advection warm fog is investigated. The equations employed in the model include the equation of continuity, momentum and energy for the descriptions of density, wind component and potential temperature, respectively, together with two diffusion equations for the modification of water-vapor mixing ratio and liquid-water mixing ratios. A description of the vertical turbulent transfer of heat, moisture and momentum has been taken into consideration. The turbulent exchange coefficients adopted in the model are based on empirical flux-gradient relations.

  7. Subsurface barrier design alternatives for confinement and controlled advection flow

    SciTech Connect

    Phillips, S.J.; Stewart, W.E.; Alexander, R.G.; Cantrell, K.J.; McLaughlin, T.J.

    1994-02-01

    Various technologies and designs are being considered to serve as subsurface barriers to confine or control contaminant migration from underground waste storage or disposal structures containing radioactive and hazardous wastes. Alternatives including direct-coupled flood and controlled advection designs are described as preconceptual examples. Prototype geotechnical equipment for testing and demonstration of these alternative designs tested at the Hanford Geotechnical Development and Test Facility and the Hanford Small-Tube Lysimeter Facility include mobile high-pressure injectors and pumps, mobile transport and pumping units, vibratory and impact pile drivers, and mobile batching systems. Preliminary laboratory testing of barrier materials and additive sequestering agents have been completed and are described.

  8. Visualizing Vector Fields Using Line Integral Convolution and Dye Advection

    NASA Technical Reports Server (NTRS)

    Shen, Han-Wei; Johnson, Christopher R.; Ma, Kwan-Liu

    1996-01-01

    We present local and global techniques to visualize three-dimensional vector field data. Using the Line Integral Convolution (LIC) method to image the global vector field, our new algorithm allows the user to introduce colored 'dye' into the vector field to highlight local flow features. A fast algorithm is proposed that quickly recomputes the dyed LIC images. In addition, we introduce volume rendering methods that can map the LIC texture on any contour surface and/or translucent region defined by additional scalar quantities, and can follow the advection of colored dye throughout the volume.

  9. Whistler waves observed upstream from collisionless shocks

    NASA Technical Reports Server (NTRS)

    Fairfield, D. H.

    1974-01-01

    Waves in the frequency range 0.5-4. Hz have been studied in the region upstream of the earth's bow shock with data from the flux-gate magnetic field experiment on Imp 6. Such waves are invariably detected adjacent to the shock, persisting upstream for intervals often less than a minute but occasionally of the order of many hours. Analysis of 150 examples of these waves during a 3-month interval indicates that propagation directions generally make angles of between 20 and 40 deg with the field direction. The waves as measured in the spacecraft frame of reference are either left- or right-hand-polarized with respect to the average field direction. The left-handed waves generally have lower frequencies than the right-handed waves, and the left-handed frequencies never exceed 2.5 Hz. The measured sense of polarization is found to depend on the propagation direction (or alternatively, the field direction) relative to the solar wind direction.

  10. Internal hydraulic jumps with large upstream shear

    NASA Astrophysics Data System (ADS)

    Ogden, Kelly; Helfrich, Karl

    2015-11-01

    Internal hydraulic jumps in approximately two-layered flows with large upstream shear are investigated using numerical simulations. The simulations allow continuous density and velocity profiles, and a jump is forced to develop by downstream topography, similar to the experiments conducted by Wilkinson and Wood (1971). High shear jumps are found to exhibit significantly more entrainment than low shear jumps. Furthermore, the downstream structure of the flow has an important effect on the jump properties. Jumps with a slow upper (inactive) layer exhibit a velocity minimum downstream of the jump, resulting in a sub-critical downstream state, while flows with the same upstream vertical shear and a larger barotropic velocity remain super-critical downstream of the jump. A two-layer theory is modified to account for the vertical structure of the downstream density and velocity profiles and entrainment is allowed through a modification of the approach of Holland et al. (2002). The resulting theory can be matched reasonably well with the numerical simulations. However, the results are very sensitive to how the downstream vertical profiles of velocity and density are incorporated into the layered model, highlighting the difficulty of the two layer approximation when the shear is large.

  11. A cryogenic circulating advective multi-pass absorption cell

    NASA Astrophysics Data System (ADS)

    Stockett, M. H.; Lawler, J. E.

    2012-03-01

    A novel absorption cell has been developed to enable a spectroscopic survey of a broad range of polycyclic aromatic hydrocarbons (PAH) under astrophysically relevant conditions and utilizing a synchrotron radiation continuum to test the still controversial hypothesis that these molecules or their ions could be carriers of the diffuse interstellar bands. The cryogenic circulating advective multi-pass absorption cell resembles a wind tunnel; molecules evaporated from a crucible or injected using a custom gas feedthrough are entrained in a laminar flow of cryogenically cooled buffer gas and advected into the path of the synchrotron beam. This system includes a multi-pass optical White cell enabling absorption path lengths of hundreds of meters and a detection sensitivity to molecular densities on the order of 107 cm-3. A capacitively coupled radio frequency dielectric barrier discharge provides ionized and metastable buffer gas atoms for ionizing the candidate molecules via charge exchange and the Penning effect. Stronger than expected clustering of PAH molecules has slowed efforts to record gas phase PAH spectra at cryogenic temperatures, though such clusters may play a role in other interstellar phenomena.

  12. Advection-Based Sparse Data Management for Visualizing Unsteady Flow.

    PubMed

    Guo, Hanqi; Zhang, Jiang; Liu, Richen; Liu, Lu; Yuan, Xiaoru; Huang, Jian; Meng, Xiangfei; Pan, Jingshan

    2014-12-01

    When computing integral curves and integral surfaces for large-scale unsteady flow fields, a major bottleneck is the widening gap between data access demands and the available bandwidth (both I/O and in-memory). In this work, we explore a novel advection-based scheme to manage flow field data for both efficiency and scalability. The key is to first partition flow field into blocklets (e.g. cells or very fine-grained blocks of cells), and then (pre)fetch and manage blocklets on-demand using a parallel key-value store. The benefits are (1) greatly increasing the scale of local-range analysis (e.g. source-destination queries, streak surface generation) that can fit within any given limit of hardware resources; (2) improving memory and I/O bandwidth-efficiencies as well as the scalability of naive task-parallel particle advection. We demonstrate our method using a prototype system that works on workstation and also in supercomputing environments. Results show significantly reduced I/O overhead compared to accessing raw flow data, and also high scalability on a supercomputer for a variety of applications. PMID:26356969

  13. THE ADVECTION OF SUPERGRANULES BY THE SUN'S AXISYMMETRIC FLOWS

    SciTech Connect

    Hathaway, David H.; Williams, Peter E.; Rosa, Kevin Dela; Cuntz, Manfred E-mail: peter.williams@nasa.go

    2010-12-10

    We show that the motions of supergranules are consistent with a model in which they are simply advected by the axisymmetric flows in the Sun's surface shear layer. We produce a 10 day series of simulated Doppler images at a 15 minute cadence that reproduces most spatial and temporal characteristics seen in the SOHO/MDI Doppler data. Our simulated data have a spectrum of cellular flows with just two components-a granule component that peaks at spherical wavenumbers of about 4000 and a supergranule component that peaks at wavenumbers of about 110. We include the advection of these cellular components by the axisymmetric flows-differential rotation and meridional flow-whose variations with latitude and depth (wavenumber) are consistent with observations. We mimic the evolution of the cellular pattern by introducing random variations to the phases of the spectral components at rates that reproduce the levels of cross-correlation as functions of time and latitude. Our simulated data do not include any wave-like characteristics for the supergranules yet can reproduce the rotation characteristics previously attributed to wave-like behavior. We find rotation rates which appear faster than the actual rotation rates and attribute this to projection effects. We find that the measured meridional flow does accurately represent the actual flow and that the observations indicate poleward flow to 65{sup 0}-70{sup 0} latitude with equatorward countercells in the polar regions.

  14. Moisture advection to the Arctic : forecasted, analysed and observed

    NASA Astrophysics Data System (ADS)

    Dufour, Ambroise; Zolina, Olga

    2015-04-01

    Besides its contribution to the Arctic hydrological budget, moisture imports from mid-latitudes are also influential on shorter time scales since water vapour advection tends to occur together with extratropical cyclones. Influx of moisture to the Arctic cause the formation of clouds that have an immediate impact on the surface energy budget especially in winter. In the long run, inaccuracies in the description of cloud cover and phase lead to temperature biases in CMIP5 models. The ECMWF workshop on polar prediction has highlighted moisture advection as one of the problematic physical processes limiting the quality of forecasts. Verifying the accuracy of medium-term forecasts is of interest beyond weather prediction : it points to the ability of models to bring adequate quantities of moisture to the Arctic when they are less constrained by observations than in analyses. In this study, we have compared forecasted moisture flux fields with analyses and observations over the period 2000-2010. ECMWF's ERA-Interim provided the forecasts, extending to ten days. For the analyses, in addition to ERA-Interim, we used the Arctic System Reanalysis whose forecast model is optimized for the polar regions and runs at high resolution (30 km). Finally, the Integrated Global Radiosonde Archive data over the Arctic allowed a validation by observations.

  15. Backward fractional advection dispersion model for contaminant source prediction

    NASA Astrophysics Data System (ADS)

    Zhang, Yong; Meerschaert, Mark M.; Neupauer, Roseanna M.

    2016-04-01

    The forward Fractional Advection Dispersion Equation (FADE) provides a useful model for non-Fickian transport in heterogeneous porous media. The space FADE captures the long leading tail, skewness, and fast spreading typically seen in concentration profiles from field data. This paper develops the corresponding backward FADE model, to identify source location and release time. The backward method is developed from the theory of inverse problems, and then explained from a stochastic point of view. The resultant backward FADE differs significantly from the traditional backward Advection Dispersion Equation (ADE) because the fractional derivative is not self-adjoint and the probability density function for backward locations is highly skewed. Finally, the method is validated using tracer data from a well-known field experiment, where the peak of the backward FADE curve predicts source release time, while the median or a range of percentiles can be used to determine the most likely source location for the observed plume. The backward ADE cannot reliably identify the source in this application, since the forward ADE does not provide an adequate fit to the concentration data.

  16. Horizontal advection, diffusion and plankton spectra at the sea surface.

    NASA Astrophysics Data System (ADS)

    Bracco, A.; Clayton, S.; Pasquero, C.

    2009-04-01

    Plankton patchiness is ubiquitous in the oceans, and various physical and biological processes have been proposed as its generating mechanisms. However, a coherent statement on the problem is missing, due to both a small number of suitable observations and to an incomplete understanding of the properties of reactive tracers in turbulent media. Abraham (1998) suggested that horizontal advection may be the dominant process behind the observed distributions of phytoplankton and zooplankton, acting to mix tracers with longer reaction times (Rt) down to smaller scales. Conversely, Mahadevan and Campbell (2002) attributed the relative distributions of sea surface temperature and phytoplankton to small scale upwelling, where tracers with longer Rt are able to homogenize more than those with shorter reaction times. Neither of the above mechanisms can explain simultaneously the (relative) spectral slopes of temperature, phytoplankton and zooplankton. Here, with a simple advection model and a large suite of numerical experiments, we concentrate on some of the physical processes influencing the relative distributions of tracers at the ocean surface, and we investigate: 1) the impact of the spatial scale of tracer supply; 2) the role played by coherent eddies on the distribution of tracers with different Rt; 3) the role of diffusion (so far neglected). We show that diffusion determines the distribution of temperature, regardless of the nature of the forcing. We also find that coherent structures together with differential diffusion of tracers with different Rt impact the tracer distributions. This may help in understanding the highly variable nature of observed plankton spectra.

  17. SEPs Dropout Events Associated with Advected Interplanetary Magnetic Structures

    NASA Astrophysics Data System (ADS)

    Bruno, R.; Trenchi, L.; Telloni, D.; D'Amicis, R.; Marcucci, F.; Zurbuchen, T.; Weberg, M. J.

    2013-05-01

    The intensity profile of energetic particles from impulsive solar flares (SEP) often shows abrupt dropouts affecting all energies simultaneously, without time-dispersion. Part of the community thinks that these modulations are directly related to the presence of magnetic structures with a different magnetic topology advected by the wind, a sort of magnetic flux tubes. During the expansion, following the dynamical interaction between plasma regions travelling at different speed, these structures would be partially tangled up in a sort of spaghetti-like bundle. These flux tubes would be alternatively connected or not connected with the flare site and, consequently, they would be filled or devoid of SEPs. When the observer passes through them, he would observe clear particles dropout signatures. We will report about results from a detailed analysis of SEP events which showed several signatures in the local magnetic field and/or plasma parameters associated with SEP modulations. These findings corroborate the idea of a possible link between these particles events observed at the Earth's orbit and magnetic connection or disconnection of the ambient magnetic field with the flare region at the Sun. We will also discuss the advantages represented by future Solar Orbiter in-situ observations. As a matter of fact, Solar Orbiter, from its orbital vantage point during the quasi corotation phase, will be a priviledged observer of this kind of phenomenon since it will observe the advected structure of the solar wind not yet reprocessed by dynamical interaction due to wind expansion.

  18. Toward enhanced subsurface intervention methods using chaotic advection.

    PubMed

    Trefry, Michael G; Lester, Daniel R; Metcalfe, Guy; Ord, Alison; Regenauer-Lieb, Klaus

    2012-01-01

    Many intervention activities in the terrestrial subsurface involve the need to recover/emplace distributions of scalar quantities (e.g. dissolved phase concentrations or heat) from/in volumes of saturated porous media. These scalars can be targeted by pump-and-treat methods or by amendment technologies. Application examples include in-situ leaching for metals, recovery of dissolved contaminant plumes, or utilizing heat energy in geothermal reservoirs. While conventional pumping methods work reasonably well, costs associated with maintaining pumping schedules are high and improvements in efficiency would be welcome. In this paper we discuss how transient switching of the pressure at different wells can intimately control subsurface flow, generating a range of "programmed" flows with various beneficial characteristics. Some programs produce chaotic flows which accelerate mixing, while others create encapsulating flows which can isolate fluid zones for lengthy periods. In a simplified model of an aquifer subject to balanced pumping, chaotic flow topologies have been predicted theoretically and verified experimentally using Hele-Shaw cells. Here, a survey of the key characteristics of chaotic advection is presented. Mathematical methods are used to show how these characteristics may translate into practical situations involving regional flows and heterogeneity. The results are robust to perturbations, and withstand significant aquifer heterogeneity. It is proposed that chaotic advection may form the basis of new efficient technologies for groundwater interventions. PMID:21600670

  19. Chaotic advection in 2D anisotropic porous media

    NASA Astrophysics Data System (ADS)

    Varghese, Stephen; Speetjens, Michel; Trieling, Ruben; Toschi, Federico

    2015-11-01

    Traditional methods for heat recovery from underground geothermal reservoirs employ a static system of injector-producer wells. Recent studies in literature have shown that using a well-devised pumping scheme, through actuation of multiple injector-producer wells, can dramatically enhance production rates due to the increased scalar / heat transport by means of chaotic advection. However the effect of reservoir anisotropy on kinematic mixing and heat transport is unknown and has to be incorporated and studied for practical deployment in the field. As a first step, we numerically investigate the effect of anisotropy (both magnitude and direction) on (chaotic) advection of passive tracers in a time-periodic Darcy flow within a 2D circular domain driven by periodically reoriented diametrically opposite source-sink pairs. Preliminary results indicate that anisotropy has a significant impact on the location, shape and size of coherent structures in the Poincare sections. This implies that the optimal operating parameters (well spacing, time period of well actuation) may vary strongly and must be carefully chosen so as to enhance subsurface transport. This work is part of the research program of the Foundation for Fundamental Research on Matter (FOM), which is part of Netherlands Organisation for Scientific Research (NWO). This research program is co-financed by Shell Global Solutions International B.V.

  20. Multiple anisotropic collisions for advection-diffusion Lattice Boltzmann schemes

    NASA Astrophysics Data System (ADS)

    Ginzburg, Irina

    2013-01-01

    This paper develops a symmetrized framework for the analysis of the anisotropic advection-diffusion Lattice Boltzmann schemes. Two main approaches build the anisotropic diffusion coefficients either from the anisotropic anti-symmetric collision matrix or from the anisotropic symmetric equilibrium distribution. We combine and extend existing approaches for all commonly used velocity sets, prescribe most general equilibrium and build the diffusion and numerical-diffusion forms, then derive and compare solvability conditions, examine available anisotropy and stable velocity magnitudes in the presence of advection. Besides the deterioration of accuracy, the numerical diffusion dictates the stable velocity range. Three techniques are proposed for its elimination: (i) velocity-dependent relaxation entries; (ii) their combination with the coordinate-link equilibrium correction; and (iii) equilibrium correction for all links. Two first techniques are also available for the minimal (coordinate) velocity sets. Even then, the two-relaxation-times model with the isotropic rates often gains in effective stability and accuracy. The key point is that the symmetric collision mode does not modify the modeled diffusion tensor but it controls the effective accuracy and stability, via eigenvalue combinations of the opposite parity eigenmodes. We propose to reduce the eigenvalue spectrum by properly combining different anisotropic collision elements. The stability role of the symmetric, multiple-relaxation-times component, is further investigated with the exact von Neumann stability analysis developed in diffusion-dominant limit.

  1. Purely Lagrangian Simulation of Advection, Dispersion, Precipitation, and Dissolution

    NASA Astrophysics Data System (ADS)

    Benson, D.; Zhang, Y.; Reeves, D. M.

    2008-05-01

    We extend the advantages of Lagrangian random walk particle tracking (RWPT) methods that have long been used to simulate advection and dispersion in highly heterogeneous media. By formulating dissolution as a random, independent decay process, the classical continuum rate law is recovered. Formulating the random precipitation process requires a consideration of the probability that two nearby particles will coincide in a given time period. This depends on local mixing (as by diffusion) and the total domain particle number density, which are fixed and therefore easy to calculate. The result is that the classical law of mass action for equilibrium reactions can be reproduced in an ensemble sense. The same number of parameters for A+B ⇌ C are needed in a probabilistic versus continuum reaction simulation-- —one each for forward and backward probabilities that correspond to rates. The random nature of the simulations allows for significant disequilibrium in any given region at any time that is independent of the numerical details such as time stepping or particle density. This is exemplified by nearby or intermingled groups of reactants and little or no product--—a result that is often noted in the field that is difficult to reconcile with continuum methods or coarse-grained Eulerian models. Our results support recent results of perturbed advection-dispersion-reaction continuum models (Luo et al., WRR 44, 2008), and suggest that many different kinds of reactions can be easily added to existing RWPT codes.

  2. A cryogenic circulating advective multi-pass absorption cell

    SciTech Connect

    Stockett, M. H.; Lawler, J. E.

    2012-03-15

    A novel absorption cell has been developed to enable a spectroscopic survey of a broad range of polycyclic aromatic hydrocarbons (PAH) under astrophysically relevant conditions and utilizing a synchrotron radiation continuum to test the still controversial hypothesis that these molecules or their ions could be carriers of the diffuse interstellar bands. The cryogenic circulating advective multi-pass absorption cell resembles a wind tunnel; molecules evaporated from a crucible or injected using a custom gas feedthrough are entrained in a laminar flow of cryogenically cooled buffer gas and advected into the path of the synchrotron beam. This system includes a multi-pass optical White cell enabling absorption path lengths of hundreds of meters and a detection sensitivity to molecular densities on the order of 10{sup 7} cm{sup -3}. A capacitively coupled radio frequency dielectric barrier discharge provides ionized and metastable buffer gas atoms for ionizing the candidate molecules via charge exchange and the Penning effect. Stronger than expected clustering of PAH molecules has slowed efforts to record gas phase PAH spectra at cryogenic temperatures, though such clusters may play a role in other interstellar phenomena.

  3. A cryogenic circulating advective multi-pass absorption cell.

    PubMed

    Stockett, M H; Lawler, J E

    2012-03-01

    A novel absorption cell has been developed to enable a spectroscopic survey of a broad range of polycyclic aromatic hydrocarbons (PAH) under astrophysically relevant conditions and utilizing a synchrotron radiation continuum to test the still controversial hypothesis that these molecules or their ions could be carriers of the diffuse interstellar bands. The cryogenic circulating advective multi-pass absorption cell resembles a wind tunnel; molecules evaporated from a crucible or injected using a custom gas feedthrough are entrained in a laminar flow of cryogenically cooled buffer gas and advected into the path of the synchrotron beam. This system includes a multi-pass optical White cell enabling absorption path lengths of hundreds of meters and a detection sensitivity to molecular densities on the order of 10(7) cm(-3). A capacitively coupled radio frequency dielectric barrier discharge provides ionized and metastable buffer gas atoms for ionizing the candidate molecules via charge exchange and the Penning effect. Stronger than expected clustering of PAH molecules has slowed efforts to record gas phase PAH spectra at cryogenic temperatures, though such clusters may play a role in other interstellar phenomena. PMID:22462957

  4. Chaotic Advection, Fluid Spreading, and Groundwater Contaminant Plumes

    NASA Astrophysics Data System (ADS)

    Neupauer, R. M.; Mays, D. C.

    2011-12-01

    In situ remediation of contaminated groundwater requires degradation reactions at the interface between the contaminant plume and an injected treatment solution containing chemical or biological amendments. Therefore a promising approach to accelerate in situ remediation is to elongate the interface between the contaminant plume and treatment solution through fluid spreading. The literature on chaotic advection describes how to accomplish spreading in laminar flows, which lack the turbulent eddies that provide spreading in streams or engineered reactors. A key result from the literature on chaotic advection is that spreading is inherent in the vicinity of certain periodic points, which are points to which fluid particles return in successive iterations of chaotic flows. Specifically, spreading is enhanced near the stable and unstable manifolds associated with hyperbolic periodic points. We investigate the transient flow created with a four-well system in which wells are operated sequentially as either injection wells or extraction wells. In particular, we identify the periodic points and demonstrate that fluid spreading occurs nearby. For appropriately designed injection and extraction sequences, the periodic points are located near the interface between the contaminant plume and treatment solution, leading to elongation of the interface, with expected benefits of enhanced reaction and accelerated remediation.

  5. Positivity-preserving numerical schemes for multidimensional advection

    NASA Technical Reports Server (NTRS)

    Leonard, B. P.; Macvean, M. K.; Lock, A. P.

    1993-01-01

    This report describes the construction of an explicit, single time-step, conservative, finite-volume method for multidimensional advective flow, based on a uniformly third-order polynomial interpolation algorithm (UTOPIA). Particular attention is paid to the problem of flow-to-grid angle-dependent, anisotropic distortion typical of one-dimensional schemes used component-wise. The third-order multidimensional scheme automatically includes certain cross-difference terms that guarantee good isotropy (and stability). However, above first-order, polynomial-based advection schemes do not preserve positivity (the multidimensional analogue of monotonicity). For this reason, a multidimensional generalization of the first author's universal flux-limiter is sought. This is a very challenging problem. A simple flux-limiter can be found; but this introduces strong anisotropic distortion. A more sophisticated technique, limiting part of the flux and then restoring the isotropy-maintaining cross-terms afterwards, gives more satisfactory results. Test cases are confined to two dimensions; three-dimensional extensions are briefly discussed.

  6. OBSERVATION OF MAGNETIC RECONNECTION DRIVEN BY GRANULAR SCALE ADVECTION

    SciTech Connect

    Zeng Zhicheng; Cao Wenda; Ji Haisheng

    2013-06-01

    We report the first evidence of magnetic reconnection driven by advection in a rapidly developing large granule using high spatial resolution observations of a small surge event (base size {approx} 4'' Multiplication-Sign 4'') with the 1.6 m aperture New Solar Telescope at the Big Bear Solar Observatory. The observations were carried out in narrowband (0.5 A) He I 10830 A and broadband (10 A) TiO 7057 A. Since He I 10830 A triplet has a very high excitation level and is optically thin, its filtergrams enable us to investigate the surge from the photosphere through the chromosphere into the lower corona. Simultaneous space data from the Atmospheric Imaging Assembly and Helioseismic and Magnetic Imager on board the Solar Dynamics Observatory were used in the analysis. It is shown that the surge is spatio-temporally associated with magnetic flux emergence in the rapidly developing large granule. During the development of the granule, its advecting flow ({approx}2 km s{sup -1}) squeezed the magnetic flux into an intergranular lane area, where a magnetic flux concentration was formed and the neighboring flux with opposite magnetic polarity was canceled. During the cancellation, the surge was produced as absorption in He I 10830 A filtergrams while simultaneous EUV brightening occurred at its base. The observations clearly indicate evidence of a finest-scale reconnection process driven by the granule's motion.

  7. Twisted Split Fermions

    SciTech Connect

    Grossman, Yuval; Harnik, Roni; Perez, Gilad; Schwartz, MatthewD.; Surujon, Ze'ev

    2004-07-30

    The observed flavor structure of the standard model arises naturally in ''split fermion'' models which localize fermions at different places in an extra dimension. It has, until now, been assumed that the bulk masses for such fermions can be chosen to be flavor diagonal simultaneously at every point in the extra dimension, with all the flavor violation coming from the Yukawa couplings to the Higgs. We consider the more natural possibility in which the bulk masses cannot be simultaneously diagonalized, that is, that they are twisted in flavor space. We show that, in general, this does not disturb the natural generation of hierarchies in the flavor parameters. Moreover, it is conceivable that all the flavor mixing and CP-violation in the standard model may come only from twisting, with the five-dimensional Yukawa couplings taken to be universal.

  8. Twisted Split Fermions

    SciTech Connect

    Grossman, Y

    2004-07-24

    The observed flavor structure of the standard model arises naturally in ''split fermion'' models which localize fermions at different places in an extra dimension. It has, until now, been assumed that the bulk masses for such fermions can be chosen to be flavor diagonal simultaneously at every point in the extra dimension, with all the flavor violation coming from the Yukawa couplings to the Higgs. We consider the more natural possibility in which the bulk masses cannot be simultaneously diagonalized, that is, that they are twisted in flavor space. We show that, in general, this does not disturb the natural generation of hierarchies in the flavor parameters. Moreover, it is conceivable that all the flavor mixing and CP-violation in the standard model may come only from twisting, with the five-dimensional Yukawa couplings taken to be universal.

  9. Moving stormwater P management upstream (Invited)

    NASA Astrophysics Data System (ADS)

    Baker, L. A.; Hobbie, S. E.; Finlay, J. C.; Kalinosky, P.; Janke, B.

    2013-12-01

    Reducing stormwater phosphorus loading using current approaches, which focus on treatment at the end of the pipe, is unlikely to reduce P loads enough to restore nutrient-impaired urban lakes. An indication of this is that of the nearly 150 nutrient impaired lakes in the Twin Cities region, only one has been restored. We hypothesize that substantial reduction of eutrophication will require reductions of P inputs upstream from storm drains. Developing source reduction strategies will required a shift in thinking about system boundaries, moving upstream from the storm drain to the curb, and from the curb to the watershed. Our Prior Lake Street Sweeping Project, a 2-year study of enhanced street sweeping, will be used to illustrate the idea of moving the system boundary to the curb. This study showed that P load recovery from sweeping increases with both sweeping frequency and overhead tree canopy cover. For high canopy streets, coarse organic material (tree leaves; seed pods, etc.) comprised 42% of swept material. We estimate that P inputs from trees may be half of measured storm P yields in 8 urban catchments in St. Paul, MN. Moreover, the cost of removing P during autumn was often < 100/pound P, compared with > 1000/lb P for stormwater ponds. We can also move further upstream, to the watershed boundary. P inputs to urban watersheds that enter lawns include lawn fertilizer, polyphosphates added to water supplies (and hence to lawns via irrigation), and pet food (transformed to pet waste). Minnesota enacted a lawn P fertilizer restriction in 2003, but early reductions in stormwater P loads were modest, probably reflecting reduction in direct wash-off of applied fertilizer. Because urban soils are enriched in P, growing turf has continued to extract available soil P. When turf is mowed, cut grass decomposes, generating P in runoff. As soil P becomes depleted, P concentrations in lawn runoff will gradually decline. Preliminary modeling suggests that substantial

  10. Suprathermal ions upstream from interplanetary shocks

    NASA Astrophysics Data System (ADS)

    Gosling, J. T.; Bame, S. J.; Feldman, W. C.; Paschmann, G.; Sckopke, N.; Russell, C. T.

    1984-07-01

    Low energy (10 eV-30 keV) observations of suprathermal ions ahead of outward propagating interplanetary shock waves (ISQ) are reported. The data were taken with the fast plasma experiment on ISEE 1 and 2 during 17 events. Structure was more evident in the suprathermal ion distribution in the earth bow shock region than in the upstream region. Isotropic distributions were only observed ahead of ISW, although field alignment, kidney-bean distributions, ion shells in velocity space and bunches of gyrating ions were not. The data suggest that the solar wind ions are accelerated to suprathermal energies in the vicinity of the shocks, which feature low and subcritical Mach numbers at 1 AU.

  11. Structural polymers in upstream production service

    SciTech Connect

    Dismukes, J.P.; Lustiger, A.; Chang, J.; Abrams, P.I.; Chiu, A.S.

    1993-12-31

    Polymers in the form of coatings, seals and composites for corrosion resistant and secondary load-bearing applications have been used in oilfield production operations for a number of years in specialty applications. The increasing needs of the industry for corrosion resistant piping, and for structural components combining corrosion resistance with high specific strength and weight, have now made the potential for use of polymer composites of increasing interest, for pipe and tubing and for load-bearing structural members. The purpose of this paper is to review the current status of structural polymer usage in the upstream, and to highlight major application areas where there is a strong economic incentive to evaluate the benefits for applying polymer composite. In addition, the underlying science and technology affecting composite properties, application life, environmental resistance and economics are assessed, since these issues need to be addressed in considering the decision to design-in composites, as compared to commonly used metals and alloys.

  12. Suprathermal ions upstream from interplanetary shocks

    NASA Technical Reports Server (NTRS)

    Gosling, J. T.; Bame, S. J.; Feldman, W. C.; Paschmann, G.; Sckopke, N.; Russell, C. T.

    1984-01-01

    Low energy (10 eV-30 keV) observations of suprathermal ions ahead of outward propagating interplanetary shock waves (ISQ) are reported. The data were taken with the fast plasma experiment on ISEE 1 and 2 during 17 events. Structure was more evident in the suprathermal ion distribution in the earth bow shock region than in the upstream region. Isotropic distributions were only observed ahead of ISW, although field alignment, kidney-bean distributions, ion shells in velocity space and bunches of gyrating ions were not. The data suggest that the solar wind ions are accelerated to suprathermal energies in the vicinity of the shocks, which feature low and subcritical Mach numbers at 1 AU.

  13. An Observational Revisit of Band-split Solar Type-II Radio Bursts

    NASA Astrophysics Data System (ADS)

    Du, Guohui; Kong, Xiangliang; Chen, Yao; Feng, Shiwei; Wang, Bing; Li, Gang

    2015-10-01

    The band split of solar type II radio bursts, discovered several decades ago, is a fascinating phenomenon, with the type II lanes exhibiting two almost parallel sub-bands with similar morphology. The underlying split mechanism remains elusive. One popular interpretation is that the splitting bands are emitted from the shock upstream and downstream, respectively, with their frequency ratio (γ) determined by the shock compression ratio. This interpretation has been taken as the physical basis of many published references. Here we report on an observational analysis of type II events with a nice split selected from ground-based RSTN data from 2001 to 2014, in the metric-decametric wavelength. We investigate the temporal variation and distribution of γ, and conduct correlation analyses on the deduced spectral values. It is found that γ varies in a very narrow range with >80% of γ (one-minute averaged data) being between 1.15 and 1.25. For some well-observed and long-lasting events, γ does not show a systematic variation trend within observational uncertainties, from the onset to the termination of the splits. In addition, the parameters representing the propagation speed of the radio source (presumably the coronal shock) show a very weak or basically no correlation with γ. We suggest that these results do not favor the upstream-downstream scenario of band splits.

  14. Blueberry Fruit Development and Splitting

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A problem facing blueberry growers in the southeastern United States is rain-related fruit splitting. Splitting refers to a break in the skin and/or pulp of the berry, prevalent in some cultivars, that occurs after a period of drought followed by intense rain. We hypothesize that blueberry cultiv...

  15. Thermally driven advection for radioxenon transport from an underground nuclear explosion

    NASA Astrophysics Data System (ADS)

    Sun, Yunwei; Carrigan, Charles R.

    2016-05-01

    Barometric pumping is a ubiquitous process resulting in migration of gases in the subsurface that has been studied as the primary mechanism for noble gas transport from an underground nuclear explosion (UNE). However, at early times following a UNE, advection driven by explosion residual heat is relevant to noble gas transport. A rigorous measure is needed for demonstrating how, when, and where advection is important. In this paper three physical processes of uncertain magnitude (oscillatory advection, matrix diffusion, and thermally driven advection) are parameterized by using boundary conditions, system properties, and source term strength. Sobol' sensitivity analysis is conducted to evaluate the importance of all physical processes influencing the xenon signals. This study indicates that thermally driven advection plays a more important role in producing xenon signals than oscillatory advection and matrix diffusion at early times following a UNE, and xenon isotopic ratios are observed to have both time and spatial dependence.

  16. A flux splitting scheme with high-resolution and robustness for discontinuities

    NASA Technical Reports Server (NTRS)

    Wada, Yasuhiro; Liou, Meng-Sing

    1994-01-01

    A flux splitting scheme is proposed for the general nonequilibrium flow equations with an aim at removing numerical dissipation of Van-Leer-type flux-vector splittings on a contact discontinuity. The scheme obtained is also recognized as an improved Advection Upwind Splitting Method (AUSM) where a slight numerical overshoot immediately behind the shock is eliminated. The proposed scheme has favorable properties: high-resolution for contact discontinuities; conservation of enthalpy for steady flows; numerical efficiency; applicability to chemically reacting flows. In fact, for a single contact discontinuity, even if it is moving, this scheme gives the numerical flux of the exact solution of the Riemann problem. Various numerical experiments including that of a thermo-chemical nonequilibrium flow were performed, which indicate no oscillation and robustness of the scheme for shock/expansion waves. A cure for carbuncle phenomenon is discussed as well.

  17. Mobile scintillometry to study heat advection over heterogeneous surfaces

    NASA Astrophysics Data System (ADS)

    Kleissl, J.

    2007-12-01

    Large Aperture Scintillometer (LAS) receivers measure the structure parameter of the refractive index from intensity fluctuations of the transmitter beam. Due to the spatial averaging over 1-4 km employed by this emerging technique the constraints for long temporal averaging (15-30 min) and associated uncertainties that have to be met by other flux measurement techniques do not apply for LASs. In this paper the constraints for temporal averaging of LASs will be examined as a function of environmental conditions and transect geometry. Moreover, analysis of data from a mobile LAS measurement across a surface gradient from rough and dry to smoother and wet will be presented. In this experiment the LAS was mounted on a pickup truck, allowing for quick redeployment of the transect after meaurement. The potential for the use of LAS to study local advection of heat in riparian or irrigated areas in the semi-arid southwest will be evaluated.

  18. Deconvolved spectra of Two Component Advective Flow including jet

    NASA Astrophysics Data System (ADS)

    Mondal, Santanu; Debnath, Dipak; Chakrabarti, Sandip Kumar

    2016-07-01

    Outflows and winds are produced when the accretion flows have positive specific energy. Two Component Advective Flow (TCAF) model suggests that the centrifugal pressure supported region of the flow outside the black hole horizon, acts as the base of this outflow. We study the spectral properties of the TCAF which includes a jet component. We consider the jet as a conical in shape which also up-scatters the soft photons from the Keplerian disc. We see that due to the presence of jet component, spectrum become harder as the jet itself behaves like an another Compton cloud above the inner hot corona. We also see how the jet spectra depends on the flow rates. This gives the direct link in timing properties of the X-rays in CENBOL component and the radiation emitted in the jet component.

  19. Carbon dioxide degassing by advective flow from Usu volcano, Japan.

    PubMed

    Hernández, P A; Notsu, K; Salazar, J M; Mori, T; Natale, G; Okada, H; Virgili, G; Shimoike, Y; Sato, M; Pérez, N M

    2001-04-01

    Magmatic carbon dioxide (CO2) degassing has been documented before the 31 March 2000 eruption of Usu volcano, Hokkaido, Japan. Six months before the eruption, an increase in CO2 flux was detected on the summit caldera, from 120 (September 1998) to 340 metric tons per day (September 1999), followed by a sudden decrease to 39 metric tons per day in June 2000, 3 months after the eruption. The change in CO2 flux and seismic observations suggests that before the eruption, advective processes controlled gas migration toward the surface. The decrease in flux after the eruption at the summit caldera could be due to a rapid release of CO2 during the eruption from ascending dacitic dikes spreading away from the magma chamber beneath the caldera. PMID:11292867

  20. Split supersymmetry radiates flavor

    NASA Astrophysics Data System (ADS)

    Baumgart, Matthew; Stolarski, Daniel; Zorawski, Thomas

    2014-09-01

    Radiative flavor models where the hierarchies of Standard Model (SM) fermion masses and mixings are explained via loop corrections are elegant ways to solve the SM flavor puzzle. Here we build such a model in the context of mini-split supersymmetry (SUSY) where both flavor and SUSY breaking occur at a scale of 1000 TeV. This model is consistent with the observed Higgs mass, unification, and dark matter as a weakly interacting massive particle. The high scale allows large flavor mixing among the sfermions, which provides part of the mechanism for radiative flavor generation. In the deep UV, all flavors are treated democratically, but at the SUSY-breaking scale, the third, second, and first generation Yukawa couplings are generated at tree level, one loop, and two loops, respectively. Save for one, all the dimensionless parameters in the theory are O(1), with the exception being a modest and technically natural tuning that explains both the smallness of the bottom Yukawa coupling and the largeness of the Cabibbo angle.

  1. How Hydrate Saturation Anomalies are Diffusively Constructed and Advectively Smoothed

    NASA Astrophysics Data System (ADS)

    Rempel, A. W.; Irizarry, J. T.; VanderBeek, B. P.; Handwerger, A. L.

    2015-12-01

    The physical processes that control the bulk characteristics of hydrate reservoirs are captured reasonably well by long-established model formulations that are rooted in laboratory-verified phase equilibrium parameterizations and field-based estimates of in situ conditions. More detailed assessments of hydrate distribution, especially involving the occurrence of high-saturation hydrate anomalies have been more difficult to obtain. Spatial variations in sediment properties are of central importance for modifying the phase behavior and promoting focussed fluid flow. However, quantitative predictions of hydrate anomaly development cannot be made rigorously without also addressing the changes in phase behavior and mechanical balances that accompany changes in hydrate saturation level. We demonstrate how pore-scale geometrical controls on hydrate phase stability can be parameterized for incorporation in simulations of hydrate anomaly development along dipping coarse-grained layers embedded in a more fine-grained background that is less amenable to fluid transport. Model simulations demonstrate how hydrate anomaly growth along coarse-layer boundaries is promoted by diffusive gas transport from the adjacent fine-grained matrix, while advective transport favors more distributed growth within the coarse-grained material and so effectively limits the difference between saturation peaks and background levels. Further analysis demonstrates how sediment contacts are unloaded once hydrate saturation reaches sufficient levels to form a load-bearing skeleton that can evolve to produce segregated nodules and lenses. Decomposition of such growth forms poses a significant geohazard that is expected to be particularly sensitive to perturbations induced by gas extraction. The figure illustrates the predicted evolution of hydrate saturation Sh in a coarse-grained dipping layer showing how prominent bounding hydrate anomalies (spikes) supplied by diffusive gas transport at early times

  2. Frictional drag reduction by wavy advection of deformable bubbles

    NASA Astrophysics Data System (ADS)

    Oishi, Yoshihiko; Murai, Yuichi; Tasaka, Yuji; Yasushi, Takeda

    2009-02-01

    Bubbles can reduce frictional drag in wall turbulence, and its effect is expected to use for ships and pipelines to save their power consumptions. A number of basic experiments have been carried out to date for finding out the best condition for enhancing the drag reduction. One issue that remains at present is the difference of the performance between steady and unsteady status in terms of bubble concentration. All the experiments in the past deal with the steady effect, i.e., the drag reduction is evaluated as a function of mean void fraction or given gas flow rate of continuous injection. Despite to this, the actual phenomena highly depend on local interaction between two phases upon unsteady manner. We focus on this point and elucidate the influence of time-fluctuating void fraction on the total response to the drag reduction. This view is in fact important to estimate the persistency of the bubble-based drag reduction in the flow direction since bubbles formulate wavy advection during their migration. Our experiments are designed to measure the above-mentioned effect from laminar, transitional, and turbulent flows in a horizontal channel. For avoiding the contamination effect that worsens the reproducibility of the experiment, Silicone oil is used as carrier fluid. The oil also simulates the high Weber number bubble condition because of low surface tension. The unsteady interaction between the wavy advection of bubbles and the local skin friction, a synchronized system is constructed to connect the high-speed camera with the shear transducer, which can evaluate the interaction at 1000 fps. From the results, we confirm that the drag reduction is provided at Re>3000 in the turbulent flow regime, and also the total drag reduction is enhanced by the presence of the waves.

  3. Multirate Runge-Kutta schemes for advection equations

    NASA Astrophysics Data System (ADS)

    Schlegel, Martin; Knoth, Oswald; Arnold, Martin; Wolke, Ralf

    2009-04-01

    Explicit time integration methods can be employed to simulate a broad spectrum of physical phenomena. The wide range of scales encountered lead to the problem that the fastest cell of the simulation dictates the global time step. Multirate time integration methods can be employed to alter the time step locally so that slower components take longer and fewer time steps, resulting in a moderate to substantial reduction of the computational cost, depending on the scenario to simulate [S. Osher, R. Sanders, Numerical approximations to nonlinear conservation laws with locally varying time and space grids, Math. Comput. 41 (1983) 321-336; H. Tang, G. Warnecke, A class of high resolution schemes for hyperbolic conservation laws and convection-diffusion equations with varying time and pace grids, SIAM J. Sci. Comput. 26 (4) (2005) 1415-1431; E. Constantinescu, A. Sandu, Multirate timestepping methods for hyperbolic conservation laws, SIAM J. Sci. Comput. 33 (3) (2007) 239-278]. In air pollution modeling the advection part is usually integrated explicitly in time, where the time step is constrained by a locally varying Courant-Friedrichs-Lewy (CFL) number. Multirate schemes are a useful tool to decouple different physical regions so that this constraint becomes a local instead of a global restriction. Therefore it is of major interest to apply multirate schemes to the advection equation. We introduce a generic recursive multirate Runge-Kutta scheme that can be easily adapted to an arbitrary number of refinement levels. It preserves the linear invariants of the system and is of third order accuracy when applied to certain explicit Runge-Kutta methods as base method.

  4. Examination of the evolution of radiation and advection fogs. Final report

    SciTech Connect

    Orgill, M.M.

    1993-01-01

    A literature study was done on radiation and advection fog evolution. For radiation fog, six stages of fog evolution have been identified -- (1) precursor, (2) sunset, (3) conditioning, (4) mature, (5) sunrise, and (6) dissipation. The evolution of advection fog models has been in parallel with radiation fog models, but no identified stages in the evolution of advection fog have been proposed: (1) precursor, (2) initiation, (3) mature, and (4) dissipation. Radiation and advection fog models will require greater sophistication in order to study fog spatial and temporal variability. Physical aspects that require further study are discussed.

  5. Escape of heated ions upstream of quasi-parallel shocks

    NASA Technical Reports Server (NTRS)

    Edmiston, J. P.; Kennel, C. F.; Eichler, D.

    1982-01-01

    A simple theoretical criterion by which quasi-parallel and quasi-perpendicular collisionless shocks may be distinguished is proposed on the basis of an investigation of the free escape of ions from the post-shock plasma into the region upstream of a fast collisionless shock. It was determined that the accessibility of downstream ions to the upstream region depends on upstream magnetic field shock normal angle, in addition to the upstream plasma parameters, with post-shock ions escaping upstream for shock normal angles of less than 45 deg, in agreement with the observed transition between quasi-parallel and quasi-perpendicular shock structure. Upstream ion distribution functions resembling those of observed intermediate ions and beams are also calculated.

  6. Upstream/downstream: Issues in environmental ethics

    SciTech Connect

    Scherer, D.

    1991-01-01

    Upstream/Downstream reminds us that there are four issues that are more or less distinctive to environmental ethics. First, and most distinctively, environmental issues involve the standing of nonhuman living things and systems. Thus, environmental politics is only partly a clash among the interest of the parties involved; it often involves actions on behalf of the existence rights of nonhuman life forms. Second, environmental ethics concern the intergenerational distribution of benefits more explicitly than do most other ethical issues, which brings out serious weaknesses in legal frameworks that rely on claims for damages. Third, the complexity and indirectness of many environmental impacts introduces a high degree of uncertainty and thus technical as well as ethical issues of prudent behavior. Specifically, where science may not fully reveal environmental risks, should development proceed; should analysis proceed if it is known to have a Pollyanna bias Fourth, insofar as environmental damage is typically done to common property, and thus its regulation is generally a matter for governmental regulation, the obligations of private actors to make sacrifices beyond what government requires is at issue - an issue that one would expect to be taken up at length in the other volumes.

  7. Developmental Origins, Epigenetics, and Equity: Moving Upstream.

    PubMed

    Wallack, Lawrence; Thornburg, Kent

    2016-05-01

    The Developmental Origins of Health and Disease and the related science of epigenetics redefines the meaning of what constitutes upstream approaches to significant social and public health problems. An increasingly frequent concept being expressed is "When it comes to your health, your zip code may be more important than your genetic code". Epigenetics explains how the environment-our zip code-literally gets under our skin, creates biological changes that increase our vulnerability for disease, and even children's prospects for social success, over their life course and into future generations. This science requires us to rethink where disease comes from and the best way to promote health. It identifies the most fundamental social equity issue in our society: that initial social and biological disadvantage, established even prior to birth, and linked to the social experience of prior generations, is made worse by adverse environments throughout the life course. But at the same time, it provides hope because it tells us that a concerted focus on using public policy to improve our social, physical, and economic environments can ultimately change our biology and the trajectory of health and social success into future generations. PMID:27029539

  8. Split-illumination electron holography

    SciTech Connect

    Tanigaki, Toshiaki; Aizawa, Shinji; Suzuki, Takahiro; Park, Hyun Soon; Inada, Yoshikatsu; Matsuda, Tsuyoshi; Taniyama, Akira; Shindo, Daisuke; Tonomura, Akira

    2012-07-23

    We developed a split-illumination electron holography that uses an electron biprism in the illuminating system and two biprisms (applicable to one biprism) in the imaging system, enabling holographic interference micrographs of regions far from the sample edge to be obtained. Using a condenser biprism, we split an electron wave into two coherent electron waves: one wave is to illuminate an observation area far from the sample edge in the sample plane and the other wave to pass through a vacuum space outside the sample. The split-illumination holography has the potential to greatly expand the breadth of applications of electron holography.

  9. A partnership in upstream HSE technology transfer

    SciTech Connect

    Olszewski, R.E. Wahjosoedibjo, A.S.; Hunley, M.; Peargin, J.C.

    1996-11-01

    The oil and gas industry was for nearly two decades the dominant force in the Indonesian economy and the single largest contributor to the nation`s development. Because of the success of Indonesia`s long-term development and diversification program, this once-dominant sector today occupies a more equal but still vital position in a better-balanced economy. The Indonesian government understands the danger to the environment posed by rapid industrial expansion and has enacted laws and regulations to ensure the sustainable development of its resources while protecting its rain forest environment. In 1992, the government oil company approached Chevron and Texaco for assistance in training its Health, Safety, and Environment (HSE) professionals. The upstream environment, health and safety training program was developed to transfer HSE knowledge and technology to PERTAMINA, PT Caltex Pacific Indonesia, a C&T affiliate, and indirectly, to the entire Indonesian oil and gas industry and government ministries. The four companies have demonstrated the effectiveness of a partnership approach in developing and carrying out HSE training. During 1994 and 1995, four groups, each consisting of about twenty representatives from PERTAMINA, the Directorate of Oil and Gas (MIGAS), the Indonesian Environmental Impact Management Agency (BAPEDAL), CPI, and Chevron and Texaco worldwide subsidiaries, traveled to the United States for an intensive four-month program of study in HSE best practices and technology conducted by Chevron and Texaco experts. This paper describes the development and realization of The PERTAMINA/CPI Health, Safety and Environment Training Program, outlines subjects covered and explains the methodology used to ensure the effective transfer of HSE knowledge and technology. The paper also offers an evaluation of the sessions and presents the plans developed by participant-teams for follow up on their return to Indonesia.

  10. Photocatalytic water splitting

    NASA Astrophysics Data System (ADS)

    Kuo, Yenting

    New photocatalystic materials Ti-In oxy(nitride) and nanosized Ru-loaded strontium titanate doped with Rh (Ru/SrTiO3:Rh) have been synthesized. The textural and surface characteristic properties were studied by nitrogen BET analysis, diffuse reflectance UV-vis spectroscopy, X-ray photoelectron spectroscopy, transmission electron microscopy, scanning electron microscopy and powder XRD. The photocatalytic properties were enhanced by the binary metal oxides of titanium dioxide and indium oxide. The XRD patterns confirmed the oxygen exchange between two metal oxides during the synthesis. Moreover, the presence of titanium dioxide can help the stabilization of InN during hot NH3(g) treatment. On the other hand, the particle sizes of aerogel prepared Ru/SrTiO3:Rh varied from 12 to 25 nm depended on different Rh doping. A mixture of ethanol and toluene was found to be the best binary solvent for supercritical drying, which yielded a SrTiO3 sample with a surface area of 130 m2/g and an average crystallite size of 6 nm. Enhanced photocatalytic hydrogen production under UV-vis light irradiation was achieved by ammonolysis of intimately mixed titanium dioxide and indium oxide at high temperatures. Gas chromatography monitored steadily the formation of hydrogen when sacrificial (methanol or ethanol) were present. XRD patterns confirmed that the photocatalysts maintain crystalline integrity before and after water splitting experiments. Moreover, the presence of InN may be crucial for the increase of hydrogen production activities. These Ru/SrTiO3:Rh photocatalysts have been studied for photocatalytic hydrogen production under visible light. The band gap of the bulk SrTiO 3 (3.2 eV) does not allow response to visible light. However, after doping with rhodium and loaded with ruthenium, the modified strontium titanates can utilize light above 400 nm due to the formation of valence band or electron donor levels inside of the band gap. Moreover, the surface areas of these

  11. Effects of thinning on transpiration by riparian buffer trees in response to advection and solar radiation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Advective energy occurring in edge environments may increase tree water use (e.g., latent heat loss, LE > net radiation, Rn). In humid agricultural landscapes, advection-enhanced transpiration in riparian buffers may provide hydrologic regulation and flood control benefits; however, research in humi...

  12. Fractional Advective-Dispersive Equation as a Model of Solute Transport in Porous Media

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Understanding and modeling transport of solutes in porous media is a critical issue in the environmental protection. The common model is the advective-dispersive equation (ADE) describing the superposition of the advective transport and the Brownian motion in water-filled pore space. Deviations from...

  13. Effects of thinning on transpiration by riparian buffer trees in response to advection and solar radiation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Advective energy occurring in edge environments may increase tree water use. In humid agricultural landscapes, advection-enhanced transpiration in riparian buffers may provide hydrologic regulation; however, research in humid environments is lacking. The objectives of this study were to determine ho...

  14. Analytical solution for the advection-dispersion transport equation in layered media

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The advection-dispersion transport equation with first-order decay was solved analytically for multi-layered media using the classic integral transform technique (CITT). The solution procedure used an associated non-self-adjoint advection-diffusion eigenvalue problem that had the same form and coef...

  15. Iteration SSII cancellation in DD-OFDM PON upstream scheme

    NASA Astrophysics Data System (ADS)

    Ju, Cheng; Liu, Na; Chen, Xue

    2016-04-01

    Iteration interference cancellation algorithm is proposed in direct detection OFDM PON upstream scheme to mitigate subcarrier to subcarrier intermixing interference (SSII) caused by dispersion and square-law photo-detection. The receiver sensitivity is improved by 1 dB in 20-Gbps, 16-QAM OFDM PON upstream experiment after 100-km standard single mode fiber (SSMF) transmission.

  16. Sanitary locking lip split well seal

    SciTech Connect

    Jozwiak, T.H.; Hunley, E.C. Jr.

    1992-05-12

    This patent describes a well seal for cooperating with a casing of a wall. It comprises a first split plate; a second split plate having a size and shape to allow insertion within the well casing; a split packer, which is provided with at least one tapered through hole, positioned between first split plate, and second split plate, the split packer having a size and shape approximately the same as an inner dimension of the well casing to allow insertion therein, split packer having at least two sections with interlocking lips to provide an effective sanitary seal by providing a leakproof labyrinth path to avoid a straight-through leak path; and clamp means for compressing split packer between first split plate and second split plates to expand the split packer into sealing engagement with an inner wall of the well casing.

  17. Low Frequency Waves at and Upstream of Collisionless Shocks

    NASA Astrophysics Data System (ADS)

    Wilson, L. B.

    2016-02-01

    This chapter focuses on the range of low frequency electromagnetic modes observed at and upstream of collisionless shocks in the heliosphere. It discusses a specific class of whistler mode wave observed immediately upstream of collisionless shock ramps, called a whistler precursor. Though these modes have been (and are often) observed upstream of quasi-parallel shocks, the authors limit their discussion to those observed upstream of quasi-perpendicular shocks. The chapter discusses the various ion velocity distributions observed at and upstream of collisionless shocks. It also introduces some terminology and relevant instabilities for ion foreshock waves. The chapter discusses the most common ultra-low frequency (ULF) wave types, their properties, and their free energy sources. It discusses modes that are mostly Alfvénic (i.e., mostly transverse but can be compressive) in nature.

  18. Sea breezes and advective effects in southwest James Bay

    NASA Technical Reports Server (NTRS)

    Mckendry, Ian; Roulet, Nigel

    1994-01-01

    Observations from a transect extending 100 km inland during the Northern Wetlands Study (NOWES) in 1990 show that the sea breeze develops on approximately 25% of days during summer and may penetrate up to 100 km inland on occasions. The sea breeze exhibits a marked diurnal clockwise rotation as a result of the Coriolis effect along the unobstructed coastline. The marine advective effect is shown to depend on gradient wind direction. With northwesterly upper level flow the sea breeze tends to be northeasterly in direction and is associated with decreased temperatures and vapor pressure deficits (VPD). With southwesterly upper level flow the sea breeze tends to have a southeasterly direction and less effect on temperatures and VPD. This is attributed to shorter residence times of air parcels over water. For two cases, Colorado State University mesoscale model simulations show good agreement with surface wind observations and suggest that under northwesterly gradient flow, Bowen ratios are increased in the onshore flow along western James Bay, while during southwesterly gradient flow these effects are negligible. These results have implications for the interpretation of local climate, ecology, and hydrology as well as land-based and airborne turbulent flux measurements made during NOWES.

  19. Sediment transport in a surface-advected estuarine plume

    NASA Astrophysics Data System (ADS)

    Yao, H. Y.; Leonardi, N.; Li, J. F.; Fagherazzi, S.

    2016-03-01

    The interplay between suspended-sediment transport and plume hydrodynamics in a surface-advected estuarine plume is studied using a three-dimensional numerical model. Our analysis focuses on the formation of a sediment-rich alongshore current and on the effect of sediments on the structure of the recirculating freshwater bulge. We introduce the ratio Y between the traveling time of sediment along the bulge edge and the settling timescale. When Y <1, suspended sediments enter the alongshore coastal current. When Y >1 the sediments are deposited within the bulge. We find that a critical range of settling velocities exist above which no transport in the costal current is allowed. Critical settling-velocity values increase with river discharge. Therefore, low magnitude and long-lasting floods promote sediment sorting in the continental shelf. We further find that, for a given flood duration, intermediate flood magnitudes at the limit between subcritical and supercritical flow maximize the alongshore sediment transport. Similarly, for a fixed input of water and sediments, intermediate discharge durations maximize alongshore sediment transport.

  20. Implementation of two-component advective flow solution in XSPEC

    NASA Astrophysics Data System (ADS)

    Debnath, Dipak; Chakrabarti, Sandip K.; Mondal, Santanu

    2014-05-01

    Spectral and temporal properties of black hole candidates can be explained reasonably well using Chakrabarti-Titarchuk solution of two-component advective flow (TCAF). This model requires two accretion rates, namely the Keplerian disc accretion rate and the halo accretion rate, the latter being composed of a sub-Keplerian, low-angular-momentum flow which may or may not develop a shock. In this solution, the relevant parameter is the relative importance of the halo (which creates the Compton cloud region) rate with respect to the Keplerian disc rate (soft photon source). Though this model has been used earlier to manually fit data of several black hole candidates quite satisfactorily, for the first time, we made it user friendly by implementing it into XSPEC software of Goddard Space Flight Center (GSFC)/NASA. This enables any user to extract physical parameters of the accretion flows, such as two accretion rates, the shock location, the shock strength, etc., for any black hole candidate. We provide some examples of fitting a few cases using this model. Most importantly, unlike any other model, we show that TCAF is capable of predicting timing properties from the spectral fits, since in TCAF, a shock is responsible for deciding spectral slopes as well as quasi-periodic oscillation frequencies. L86

  1. Revisiting the Rossby Haurwitz wave test case with contour advection

    NASA Astrophysics Data System (ADS)

    Smith, Robert K.; Dritschel, David G.

    2006-09-01

    This paper re-examines a basic test case used for spherical shallow-water numerical models, and underscores the need for accurate, high resolution models of atmospheric and ocean dynamics. The Rossby-Haurwitz test case, first proposed by Williamson et al. [D.L. Williamson, J.B. Drake, J.J. Hack, R. Jakob, P.N. Swarztrauber, A standard test set for numerical approximations to the shallow-water equations on the sphere, J. Comput. Phys. (1992) 221-224], has been examined using a wide variety of shallow-water models in previous papers. Here, two contour-advective semi-Lagrangian (CASL) models are considered, and results are compared with previous test results. We go further by modifying this test case in a simple way to initiate a rapid breakdown of the basic wave state. This breakdown is accompanied by the formation of sharp potential vorticity gradients (fronts), placing far greater demands on the numerics than the original test case does. We also go further by examining other dynamical fields besides the height and potential vorticity, to assess how well the models deal with gravity waves. Such waves are sensitive to the presence or not of sharp potential vorticity gradients, as well as to numerical parameter settings. In particular, large time steps (convenient for semi-Lagrangian schemes) can seriously affect gravity waves but can also have an adverse impact on the primary fields of height and velocity. These problems are exacerbated by a poor resolution of potential vorticity gradients.

  2. Entropy Splitting and Numerical Dissipation

    NASA Technical Reports Server (NTRS)

    Yee, H. C.; Vinokur, M.; Djomehri, M. J.

    1999-01-01

    A rigorous stability estimate for arbitrary order of accuracy of spatial central difference schemes for initial-boundary value problems of nonlinear symmetrizable systems of hyperbolic conservation laws was established recently by Olsson and Oliger (1994) and Olsson (1995) and was applied to the two-dimensional compressible Euler equations for a perfect gas by Gerritsen and Olsson (1996) and Gerritsen (1996). The basic building block in developing the stability estimate is a generalized energy approach based on a special splitting of the flux derivative via a convex entropy function and certain homogeneous properties. Due to some of the unique properties of the compressible Euler equations for a perfect gas, the splitting resulted in the sum of a conservative portion and a non-conservative portion of the flux derivative. hereafter referred to as the "Entropy Splitting." There are several potential desirable attributes and side benefits of the entropy splitting for the compressible Euler equations that were not fully explored in Gerritsen and Olsson. The paper has several objectives. The first is to investigate the choice of the arbitrary parameter that determines the amount of splitting and its dependence on the type of physics of current interest to computational fluid dynamics. The second is to investigate in what manner the splitting affects the nonlinear stability of the central schemes for long time integrations of unsteady flows such as in nonlinear aeroacoustics and turbulence dynamics. If numerical dissipation indeed is needed to stabilize the central scheme, can the splitting help minimize the numerical dissipation compared to its un-split cousin? Extensive numerical study on the vortex preservation capability of the splitting in conjunction with central schemes for long time integrations will be presented. The third is to study the effect of the non-conservative proportion of splitting in obtaining the correct shock location for high speed complex shock

  3. Relative effects of advection, sorption and diffusion on transport and tailing of chlorinated solvents

    NASA Astrophysics Data System (ADS)

    Maghrebi, M.; Jankovic, I.; Rabideau, A. J.; Allen-King, R. M.; Weissmann, G. S.

    2011-12-01

    Effects of three key transport mechanisms (advection, diffusion and sorption) on transport and contaminant tailing of chlorinated solvents have been investigated using a numerical model. Thousands of model simulations have been conducted for various combinations of transport parameters that govern three key mechanisms in order to quantify tailing and relative importance of each mechanism. Hydraulic conductivity model contains a single inclusion of constant conductivity K embedded in a homogeneous anisotropic background of conductivity Kh,Kv. The inclusion is shaped as an oblate ellipsoid and subject to uniform flow. The background represents "average" conductivity of a heterogeneous formation while inclusion is used to represent geologic units that are more or less conductive than the background. The ratio of long to short semi-axis of the inclusion (a/b) models the ratio of horizontal to vertical integral scales (Ih/Iv) of different geologic units, where integral scales can be obtained, for example, using indicator variograms. The flow solution for present problem is obtained analytically as a closed form solution with exact expressions for Darcy velocity valid both inside and outside the inclusion. Sorption is modeled as an equilibrium process governed by a linear isotherm. The effects on transport and tailing are accounted for using retardation factors. Sorption heterogeneity is created by allowing different values of retardation factor for the interior (Ri) and the exterior of the inclusion (Rb). Diffusive displacements have been added to retarded advective displacements using random walk method. Peclet number, defined as Pe=U Ih/D (U is the groundwater velocity, D is the molecular diffusion coefficient for chlorinated solvents), is used to quantify the diffusion process. Very large numbers of particles (hundreds of thousands) have been tracked using very small time steps (as small as a/10,000) to provide sufficient resolution to breakthrough curves and to

  4. Application of a monotonic upstream-biased transport scheme to three-dimensional constituent transport calculations

    NASA Technical Reports Server (NTRS)

    Allen, Dale J.; Douglass, Anne R.; Rood, Richard B.; Guthrie, Paul D.

    1991-01-01

    The application of van Leer's scheme, a monotonic, upstream-biased differencing scheme, to three-dimensional constituent transport calculations is shown. The major disadvantage of the scheme is shown to be a self-limiting diffusion. A major advantage of the scheme is shown to be its ability to maintain constituent correlations. The scheme is adapted for a spherical coordinate system with a hybrid sigma-pressure coordinate in the vertical. Special consideration is given to cross-polar flow. The vertical wind calculation is shown to be extremely sensitive to the method of calculating the divergence. This sensitivity implies that a vertical wind formulation consistent with the transport scheme is essential for accurate transport calculations. The computational savings of the time-splitting method used to solve this equation are shown. Finally, the capabilities of this scheme are illustrated by an ozone transport and chemistry model simulation.

  5. An upstream reach-extender for 10Gb/s PON applications based on an optimized semiconductor amplifier cascade.

    PubMed

    Porto, Stefano; Antony, Cleitus; Ossieur, Peter; Townsend, Paul D

    2012-01-01

    We present a reach-extender for the upstream transmission path of 10Gb/s passive optical networks based on an optimised cascade of two semiconductor optical amplifiers (SOAs). Through careful optimisation of the bias current of the second stage SOA, over 19dB input dynamic range and up to 12dB compression of the output dynamic range were achieved without any dynamic control. A reach of 70km and split up to 32 were demonstrated experimentally using an ac-coupled, continuous-mode receiver with a reduced 56ns ac-coupling constant. PMID:22274342

  6. Simulation of Field-Scale Non-Fickian Plumes With Spatiotemporal Fractional Advection- Dispersion Equations

    NASA Astrophysics Data System (ADS)

    Benson, D. A.; Zhang, Y.

    2006-12-01

    Conservative solute transport through natural media is typically "anomalous" or non-Fickian. The anomalous transport may be characterized by faster than linear growth of the centered second moment, or non-Gaussian leading or trailing edges of a plume emanating from a point source. These characteristics develop because of non-local dependence on either past (time) or far upstream (space) concentrations. Non-local equations developed to describe anomalous dispersion usually focus on constant transport parameters and/or independence of the transport on space dimension. These simplifications have been useful for fitting simple transport processes, such as laboratory column tests or 1-D projections of field data. However, they may be insufficient for real field settings, where direction-dependent depositional processes and nonstationary heterogeneity can occur. We develop a generalized, multi-dimensional, spatiotemporal fractional advection- dispersion equation (fADE) with variable parameters to characterize regional-scale anomalous dispersion processes including trapping in immobile zones and/or super-Fickian rapid transport. A Lagrangian numerical model of the space-time fractional transport equation is developed in which solute particles can disperse in both space and time, depending on the medium heterogeneity properties, such as the connectivity and statistical distributions of high versus low-permeability deposits. In the generalized fADE, the range of the order of fractional time derivative is (0 2], representing a wide range of possible trapping behavior. The extension of the order to the range (1 2] is novel to transport theory. We apply the numerical model in 1-D and 2-D to the MADE site tritium plumes, and results indicate that this method can capture the main behaviors of realistic plumes, including local variations of spreading, direction-dependent scaling rates, and arbitrary rapid transport along preferential flow paths. Since the governing equation

  7. BEHAVIOR OF SENSITIVITIES IN THE ONE-DIMENSIONAL ADVECTION-DISPERSION EQUATION: IMPLICATIONS FOR PARAMETER ESTIMATION AND SAMPLING DESIGN.

    USGS Publications Warehouse

    Knopman, Debra S.; Voss, Clifford I.

    1987-01-01

    The spatial and temporal variability of sensitivities has a significant impact on parameter estimation and sampling design for studies of solute transport in porous media. Physical insight into the behavior of sensitivities is offered through an analysis of analytically derived sensitivities for the one-dimensional form of the advection-dispersion equation. When parameters are estimated in regression models of one-dimensional transport, the spatial and temporal variability in sensitivities influences variance and covariance of parameter estimates. Several principles account for the observed influence of sensitivities on parameter uncertainty. (1) Information about a physical parameter may be most accurately gained at points in space and time. (2) As the distance of observation points from the upstream boundary increases, maximum sensitivity to velocity during passage of the solute front increases. (3) The frequency of sampling must be 'in phase' with the S shape of the dispersion sensitivity curve to yield the most information on dispersion. (4) The sensitivity to the dispersion coefficient is usually at least an order of magnitude less than the sensitivity to velocity. (5) The assumed probability distribution of random error in observations of solute concentration determines the form of the sensitivities. (6) If variance in random error in observations is large, trends in sensitivities of observation points may be obscured by noise. (7) Designs that minimize the variance of one parameter may not necessarily minimize the variance of other parameters.

  8. A family of Eulerian-Lagrangian localized adjoint methods for multi-dimensional advection-reaction equations

    SciTech Connect

    Wang, H.; Man, S.; Ewing, R.E.; Qin, G.; Lyons, S.L.; Al-Lawatia, M.

    1999-06-10

    Many difficult problems arise in the numerical simulation of fluid flow processes within porous media in petroleum reservoir simulation and in subsurface contaminant transport and remediation. The authors develop a family of Eulerian-Lagrangian localized adjoint methods for the solution of the initial-boundary value problems for first-order advection-reaction equations on general multi-dimensional domains. Different tracking algorithms, including the Euler and Runge-Kutta algorithms, are used. The derived schemes, which are full mass conservative, naturally incorporate inflow boundary conditions into their formulations and do not need any artificial outflow boundary conditions. Moreover, they have regularly structured, well-conditioned, symmetric, and positive-definite coefficient matrices, which can be efficiently solved by the conjugate gradient method in an optimal order number of iterations without any preconditioning needed. Numerical results are presented to compare the performance of the ELLAM schemes with many well studied and widely used methods, including the upwind finite difference method, the Galerkin and the Petrov-Galerkin finite element methods with backward-Euler or Crank-Nicolson temporal discretization, the streamline diffusion finite element methods, the monotonic upstream-centered scheme for conservation laws (MUSCL), and the Minmod scheme.

  9. Round window membrane intracochlear drug delivery enhanced by induced advection.

    PubMed

    Borkholder, David A; Zhu, Xiaoxia; Frisina, Robert D

    2014-01-28

    Delivery of therapeutic compounds to the inner ear via absorption through the round window membrane (RWM) has advantages over direct intracochlear infusions; specifically, minimizing impact upon functional hearing measures. However, previous reports show that significant basal-to-apical concentration gradients occur, with the potential to impact treatment efficacy. Here we present a new approach to inner ear drug delivery with induced advection aiding distribution of compounds throughout the inner ear in the murine cochlea. Polyimide microtubing was placed near the RWM niche through a bullaostomy into the middle ear cavity allowing directed delivery of compounds to the RWM. We hypothesized that a posterior semicircular canalostomy would induce apical flow from the patent cochlear aqueduct to the canalostomy due to influx of cerebral spinal fluid. To test this hypothesis, young adult CBA/CaJ mice were divided into two groups: bullaostomy approach only (BA) and bullaostomy+canalostomy (B+C). Cochlear function was evaluated by distortion product otoacoustic emission (DPOAE) and auditory brainstem response (ABR) thresholds during and after middle ear infusion of salicylate in artificial perilymph (AP), applied near the RWM. The mice recovered for 1week, and were re-tested. The results demonstrate there was no significant impact on auditory function utilizing the RWM surgical procedure with or without the canalostomy, and DPOAE thresholds were elevated reversibly during the salicylate infusion. Comparing the threshold shifts for both methods, the B+C approach had more of a physiological effect than the BA approach, including at lower frequencies representing more apical cochlear locations. Unlike mouse cochleostomies, there was no deleterious auditory functional impact after 1week recovery from surgery. The B+C approach had more drug efficacy at lower frequencies, underscoring potential benefits for more precise control of delivery of inner ear therapeutic compounds

  10. Round Window Membrane Intracochlear Drug Delivery Enhanced by Induced Advection

    PubMed Central

    Borkholder, David A.; Zhu, Xiaoxia; Frisina, Robert D.

    2014-01-01

    Delivery of therapeutic compounds to the inner ear via absorption through the round window membrane (RWM) has advantages over direct intracochlear infusions; specifically, minimizing impact upon functional hearing measures. However, previous reports show that significant basal-to-apical concentration gradients occur, with the potential to impact treatment efficacy. Here we present a new approach to inner ear drug delivery with induced advection aiding distribution of compounds throughout the inner ear in the murine cochlea. Polyimide microtubing was placed near the RWM niche through a bullaostomy into the middle ear cavity allowing directed delivery of compounds to the RWM. We hypothesized that a posterior semicircular canalostomy would induce apical flow from the patent cochlear aqueduct to the canalostomy due to influx of cerebral spinal fluid. To test this hypothesis, young adult CBA/CaJ mice were divided into two groups: bullaostomy approach only (BA) and bullaostomy + canalostomy (B+C). Cochlear function was evaluated by distortion product otoacoustic emission (DPOAE) and auditory brainstem response (ABR) thresholds during and after middle ear infusion of salicylate in artificial perilymph (AP), applied near the RWM. The mice recovered for 1 week, and were re-tested. The results demonstrate there was no significant impact on auditory function utilizing the RWM surgical procedure with or without the canalostomy, and DPOAE thresholds were elevated reversibly during the salicylate infusion. Comparing the threshold shifts for both methods, the B+C approach had more of a physiological effect than the BA approach, including at lower frequencies representing more apical cochlear locations. Unlike mouse cochleostomies, there was no deleterious auditory functional impact after 1 week recovery from surgery. The B+C approach had more drug efficacy at lower frequencies, underscoring potential benefits for more precise control of delivery of inner ear therapeutic compounds

  11. Evaporation of traffic-generated nanoparticles during advection from source

    NASA Astrophysics Data System (ADS)

    Harrison, Roy M.; Jones, Alan M.; Beddows, David C. S.; Dall'Osto, Manuel; Nikolova, Irina

    2016-01-01

    Earlier work has demonstrated the potential for volatilisation of nanoparticles emitted by road traffic as these are advected downwind from the source of emissions, but there have been few studies and the processes have yet to be elucidated in detail. Using a dataset collected at paired sampling sites located respectively in a street canyon and in a nearby park, an in depth analysis of particle number size distributions has been conducted in order to better understand the size reduction of the semi-volatile nanoparticles. By sorting the size distributions according to wind direction and fitting log normal modes, it can be seen that the mode peaking at around 22 nm at the street canyon site is on average shrinking to 6.2 nm diameter at the park site which indicates a mean shrinkage rate for these particles of 0.13 nm s-1 with temperatures within the range 12-18 °C. The diurnal variation of the shrunken mode in the park reflects the diurnal pattern of particle concentrations at the street canyon site taken as the main source area. An analysis of peak diameter for the smallest mode at the downwind park site shows an inverse relationship to wind speed suggesting that dilution rather than travel time is the main determinant of the particle shrinkage rate. An evaluation of previously collected C10 to C35 n-alkane data from a different urban location shows a good fit to Pankow partitioning theory reflecting the semi-volatility of compounds believed to be representative of the composition of diesel exhaust nanoparticles, hence confirming the feasibility of an evaporative mechanism for particle shrinkage.

  12. Advective hydrogel membrane chromatography for monoclonal antibody purification in bioprocessing.

    PubMed

    Hou, Ying; Brower, Mark; Pollard, David; Kanani, Dharmesh; Jacquemart, Renaud; Kachuik, Bradley; Stout, James

    2015-01-01

    Protein A chromatography is widely employed for the capture and purification of monoclonal antibodies (mAbs). Because of the high cost of protein A resins, there is a significant economic driving force to seek new downstream processing strategies. Membrane chromatography has emerged as a promising alternative to conventional resin based column chromatography. However, to date, the application has been limited to mostly ion exchange flow through (FT) mode. Recently, significant advances in Natrix hydrogel membrane has resulted in increased dynamic binding capacities for proteins, which makes membrane chromatography much more attractive for bind/elute operations. The dominantly advective mass transport property of the hydrogel membrane has also enabled Natrix membrane to be run at faster volumetric flow rates with high dynamic binding capacities. In this work, the potential of using Natrix weak cation exchange membrane as a mAb capture step is assessed. A series of cycle studies was also performed in the pilot scale device (> 30 cycles) with good reproducibility in terms of yield and product purities, suggesting potential for improved manufacturing flexibility and productivity. In addition, anion exchange (AEX) hydrogel membranes were also evaluated with multiple mAb programs in FT mode. Significantly higher binding capacity for impurities (support mAb loads up to 10Kg/L) and 40X faster processing speed were observed compared with traditional AEX column chromatography. A proposed protein A free mAb purification process platform could meet the demand of a downstream purification process with high purity, yield, and throughput. PMID:26018631

  13. Critical time scales for advection-diffusion-reaction processes

    NASA Astrophysics Data System (ADS)

    Ellery, Adam J.; Simpson, Matthew J.; McCue, Scott W.; Baker, Ruth E.

    2012-04-01

    The concept of local accumulation time (LAT) was introduced by Berezhkovskii and co-workers to give a finite measure of the time required for the transient solution of a reaction-diffusion equation to approach the steady-state solution [A. M. Berezhkovskii, C. Sample, and S. Y. Shvartsman, Biophys. J.BIOJAU0006-349510.1016/j.bpj.2010.07.045 99, L59 (2010); A. M. Berezhkovskii, C. Sample, and S. Y. Shvartsman, Phys. Rev. EPLEEE81539-375510.1103/PhysRevE.83.051906 83, 051906 (2011)]. Such a measure is referred to as a critical time. Here, we show that LAT is, in fact, identical to the concept of mean action time (MAT) that was first introduced by McNabb [A. McNabb and G. C. Wake, IMA J. Appl. Math.IJAMDM0272-496010.1093/imamat/47.2.193 47, 193 (1991)]. Although McNabb's initial argument was motivated by considering the mean particle lifetime (MPLT) for a linear death process, he applied the ideas to study diffusion. We extend the work of these authors by deriving expressions for the MAT for a general one-dimensional linear advection-diffusion-reaction problem. Using a combination of continuum and discrete approaches, we show that MAT and MPLT are equivalent for certain uniform-to-uniform transitions; these results provide a practical interpretation for MAT by directly linking the stochastic microscopic processes to a meaningful macroscopic time scale. We find that for more general transitions, the equivalence between MAT and MPLT does not hold. Unlike other critical time definitions, we show that it is possible to evaluate the MAT without solving the underlying partial differential equation (pde). This makes MAT a simple and attractive quantity for practical situations. Finally, our work explores the accuracy of certain approximations derived using MAT, showing that useful approximations for nonlinear kinetic processes can be obtained, again without treating the governing pde directly.

  14. Verification of Advective Bar Elements Implemented in the Aria Thermal Response Code.

    SciTech Connect

    Mills, Brantley

    2016-01-01

    A verification effort was undertaken to evaluate the implementation of the new advective bar capability in the Aria thermal response code. Several approaches to the verification process were taken : a mesh refinement study to demonstrate solution convergence in the fluid and the solid, visually examining the mapping of the advective bar element nodes to the surrounding surfaces, and a comparison of solutions produced using the advective bars for simple geometries with solutions from commercial CFD software . The mesh refinement study has shown solution convergence for simple pipe flow in both temperature and velocity . Guidelines were provided to achieve appropriate meshes between the advective bar elements and the surrounding volume. Simulations of pipe flow using advective bars elements in Aria have been compared to simulations using the commercial CFD software ANSYS Fluent (r) and provided comparable solutions in temperature and velocity supporting proper implementation of the new capability. Verification of Advective Bar Elements iv Acknowledgements A special thanks goes to Dean Dobranich for his guidance and expertise through all stages of this effort . His advice and feedback was instrumental to its completion. Thanks also goes to Sam Subia and Tolu Okusanya for helping to plan many of the verification activities performed in this document. Thank you to Sam, Justin Lamb and Victor Brunini for their assistance in resolving issues encountered with running the advective bar element model. Finally, thanks goes to Dean, Sam, and Adam Hetzler for reviewing the document and providing very valuable comments.

  15. Suprathermal ions observed upstream of the Venus bow shock

    NASA Technical Reports Server (NTRS)

    Moore, K. R.; Mccomas, D. J.; Russell, C. T.; Mihalov, J. D.

    1989-01-01

    Suprathermal ions with arrival directions quite distinct from those of the solar wind have been detected upstream of the Venus bow shock. The possibility that these events could be caused by instrumental or spacecraft effects or that they could be either solar wind disturbances, planetary pickup ions, or suprethermal ions upstream of the Venus bow shock is examined. It is concluded that they are consistent with upstream suprathermal ions associated with the bow shock that are observed downstream from the points of intersection of their extrapolated trajectories with the shock.

  16. The Upstream Hospital Leader: Taking Action to Improve Population Health.

    PubMed

    Graham, Ross; Meili, Ryan

    2016-01-01

    Canadian hospital leaders face numerous barriers when they seek to work upstream in an effort to improve population health. A noted challenge is lack of role clarity. We introduce the concept of an "upstream hospital leader" in an attempt to address this challenge, and suggest behaviours for how this role can advance population health at the individual, organizational and health system levels. These suggestions aim to contribute to the ongoing conversation and growing interest in the role of hospitals in population health improvement. We invite feedback on these suggestions and encourage leaders to explore opportunities where greater upstream action by their hospital and health system can improve population health. PMID:27009704

  17. The contiguous domains of Arctic Ocean advection: Trails of life and death

    NASA Astrophysics Data System (ADS)

    Wassmann, P.; Kosobokova, K. N.; Slagstad, D.; Drinkwater, K. F.; Hopcroft, R. R.; Moore, S. E.; Ellingsen, I.; Nelson, R. J.; Carmack, E.; Popova, E.; Berge, J.

    2015-12-01

    The central Arctic Ocean is not isolated, but tightly connected to the northern Pacific and Atlantic Oceans. Advection of nutrient-, detritus- and plankton-rich waters into the Arctic Ocean forms lengthy contiguous domains that connect subarctic with the arctic biota, supporting both primary production and higher trophic level consumers. In turn, the Arctic influences the physical, chemical and biological oceanography of adjacent subarctic waters through southward fluxes. However, exports of biomass out of the Arctic Ocean into both the Pacific and Atlantic Oceans are thought to be far smaller than the northward influx. Thus, Arctic Ocean ecosystems are net biomass beneficiaries through advection. The biotic impact of Atlantic- and Pacific-origin taxa in arctic waters depends on the total supply of allochthonously-produced biomass, their ability to survive as adults and their (unsuccessful) reproduction in the new environment. Thus, advective transport can be thought of as trails of life and death in the Arctic Ocean. Through direct and indirect (mammal stomachs, models) observations this overview presents information about the advection and fate of zooplankton in the Arctic Ocean, now and in the future. The main zooplankton organisms subjected to advection into and inside the Arctic Ocean are (a) oceanic expatriates of boreal Atlantic and Pacific origin, (b) oceanic Arctic residents and (c) neritic Arctic expatriates. As compared to the Pacific gateway the advective supply of zooplankton biomass through the Atlantic gateways is 2-3 times higher. Advection characterises how the main planktonic organisms interact along the contiguous domains and shows how the subarctic production regimes fuel life in the Arctic Ocean. The main differences in the advective regimes through the Pacific and Atlantic gateways are presented. The Arctic Ocean is, at least in some regions, a net heterotrophic ocean that - during the foreseeable global warming trend - will more and more rely

  18. Lattice splitting under intermittent flows

    NASA Astrophysics Data System (ADS)

    Schläpfer, Markus; Trantopoulos, Konstantinos

    2010-05-01

    We study the splitting of regular square lattices subject to stochastic intermittent flows. Various flow patterns are produced by different groupings of the nodes, based on their random alternation between two possible states. The resulting flows on the lattices decrease with the number of groups according to a power law. By Monte Carlo simulations we reveal how the time span until the occurrence of a splitting depends on the flow patterns. Increasing the flow fluctuation frequency shortens this time span, which reaches a minimum before rising again due to inertia effects incorporated in the model. The size of the largest connected component after the splitting is rather independent of the flow fluctuation frequency but slightly decreases with the link capacities. Our findings carry important implications for real-world networks, such as electric power grids with a large share of renewable intermittent energy sources.

  19. Lattice splitting under intermittent flows.

    PubMed

    Schläpfer, Markus; Trantopoulos, Konstantinos

    2010-05-01

    We study the splitting of regular square lattices subject to stochastic intermittent flows. Various flow patterns are produced by different groupings of the nodes, based on their random alternation between two possible states. The resulting flows on the lattices decrease with the number of groups according to a power law. By Monte Carlo simulations we reveal how the time span until the occurrence of a splitting depends on the flow patterns. Increasing the flow fluctuation frequency shortens this time span, which reaches a minimum before rising again due to inertia effects incorporated in the model. The size of the largest connected component after the splitting is rather independent of the flow fluctuation frequency but slightly decreases with the link capacities. Our findings carry important implications for real-world networks, such as electric power grids with a large share of renewable intermittent energy sources. PMID:20866296

  20. Measurement of advection of CO2 over grasslands in complex terrain in the Alps

    NASA Astrophysics Data System (ADS)

    Zhao, Peng; Hammerle, Albin; Wohlfahrt, Georg

    2015-04-01

    The role of advection is often ignored in the estimation of net ecosystem exchange (NEE) of CO2 in ecosystems. However, some studies reported that more realistic estimates of night-time NEE could be gathered if horizontal and vertical advections are included. While most of previous advection experiments have been conducted in forest ecosystems, grassland ecosystems have a great advantage as measurements of advection can be realised with smaller infrastructure and thus less experimental effort. In a preliminary simplified study, advection showed an important contribution to NEE during night time at a sub-alpine grassland site. This three-year program is focused on the role of advection for NEE of grassland ecosystems in complex terrain in the Alps. We are going to carry out field campaigns at four sites which cover a range of terrain types typical for mountains with varying degrees of complexity, including a valley-bottom site, a steep-slope site, a mixed-terrain site, and an undulating-terrain site. Observations will take place in a notional control volume with a length varying from 50 m to 5 m at each site in order to quantify the effects of horizontal spatial scale on advection estimates. The observations at each site include vertical flux of CO2 measured by eddy-covariance technique, horizontal and vertical advections of CO2 calculated from the measurement of wind components and CO2 gradients, and NEE measured by chambers. Among all, the measurement of the horizontal advection of CO2 needs many efforts because of small-scale variability in sources/sinks of CO2. We are going to use tubes with multiple inlets, which allows sampling at multiple positions across the faces at three heights of the control volume. Thus, we would be able to quantify the contribution of advection to NEE at different grassland sites situated in complex terrain in the Alps, and to quantify the effect of spatial scale of advection measurements with a given experimental setup and accuracy on

  1. Split ring containment attachment device

    DOEpatents

    Sammel, Alfred G.

    1996-01-01

    A containment attachment device 10 for operatively connecting a glovebag 200 to plastic sheeting 100 covering hazardous material. The device 10 includes an inner split ring member 20 connected on one end 22 to a middle ring member 30 wherein the free end 21 of the split ring member 20 is inserted through a slit 101 in the plastic sheeting 100 to captively engage a generally circular portion of the plastic sheeting 100. A collar potion 41 having an outer ring portion 42 is provided with fastening means 51 for securing the device 10 together wherein the glovebag 200 is operatively connected to the collar portion 41.

  2. Baryon asymmetry and split SUSY

    SciTech Connect

    Kasuya, Shinta

    2005-12-02

    It is one of the greatest mysteries that the baryon asymmetry in our universe is so small. It is argued that it may originate from some profound physics beyond the standard model. We investigate the Affleck-Dine baryogenesis in split supersymmetry, and find that the smallness of the baryon asymmetry is directly related to the hierarchy between the supersymmetry breaking squark/slepton masses and the weak scale. Put simply, the baryon asymmetry is small because of the split mass spectrum. LHC may prove or falsify our scenario.

  3. SEBAL-A: A remote sensing ET algorithm that accounts for advection with limited data. Part II: Test for transferability

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Because the Surface Energy Balance Algorithm for Land (SEBAL) tends to underestimate ET under conditions of advection, the model was modified by incorporating an advection component as part of the energy usable for crop evapotranspiration (ET). The modification involved the estimation of advected en...

  4. Mitigation of Rayleigh backscattering in 10-Gb/s downstream and 2.5-Gb/s upstream DWDM 100-km long-reach PONs.

    PubMed

    Chow, C W; Yeh, C H

    2011-03-14

    Long-reach passive optical network (LR-PON) is considered as a promising technology towards higher capacity and extended coverage optical system. We propose and demonstrate a LR-PON with the capability of Rayleigh backscattering (RB) noise mitigation. By using the upstream signal wavelength-transition generated by a dual-parallel Mach-Zehnder modulator (DP-MZM) based colorless optical networking unit (ONU), the spectral overlap among the upstream signal and the RB noises can be minimized. Hence, due to the achievement of effective RB mitigation, a 100 km LR-PON with a high split-ratio of 512 is demonstrated using 10 Gb/s non-return-to-zero (NRZ) downstream and 2.5 Gb/s NRZ upstream signals. Detail analysis of the wavelength-transition generation is presented. PMID:21445132

  5. 4. VIEW SHOWING UPSTREAM FACE OF DAM, LOOKING NORTHEAST ...

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

    4. VIEW SHOWING UPSTREAM FACE OF DAM, LOOKING NORTHEAST - High Mountain Dams in Upalco Unit, Kidney Lake Dam, Ashley National Forest, 4.7 miles North of Miners Gulch Campground, Mountain Home, Duchesne County, UT

  6. 3. OVERALL VIEW OF DAM, SHOWING UPSTREAM FACE, LOOKING EAST ...

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

    3. OVERALL VIEW OF DAM, SHOWING UPSTREAM FACE, LOOKING EAST - High Mountain Dams in Upalco Unit, Kidney Lake Dam, Ashley National Forest, 4.7 miles North of Miners Gulch Campground, Mountain Home, Duchesne County, UT

  7. OVERALL VIEW OF CASCADE CANAL COMPANY CRIB DAM, LOOKING UPSTREAM ...

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

    OVERALL VIEW OF CASCADE CANAL COMPANY CRIB DAM, LOOKING UPSTREAM FROM DIRECTION OF KACHESS DAM. VIEW TO NORTH - Kachess Dam, 1904 Cascade Canal Company Crib Dam, Kachess River, 1.5 miles north of Interstate 90, Easton, Kittitas County, WA

  8. 10. UPSTREAM EXTENSION TO 60' INFILTRATION PIPE: MISCELLANEOUS METAL DETAILS. ...

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

    10. UPSTREAM EXTENSION TO 60' INFILTRATION PIPE: MISCELLANEOUS METAL DETAILS. Sheet A-22, November, 1940. File no. SA 342/31. - Prado Dam, Embankment, Santa Ana River near junction of State Highways 71 & 91, Corona, Riverside County, CA

  9. 2. UPSTREAM SIDE OF DIVERSION DAM ON THE SNAKE RIVER, ...

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

    2. UPSTREAM SIDE OF DIVERSION DAM ON THE SNAKE RIVER, LOOKING SOUTH-SOUTHWEST. NOTE BANK REINFORCEMENT ON LEFT AND SPILLWAY ON RIGHT. - Snake River Ditch, Headgate on north bank of Snake River, Dillon, Summit County, CO

  10. 63. INTERIOR VIEW OF UPSTREAM LOCKKEEPER'S HOUSE, SHOWING FIRST FLOOR ...

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

    63. INTERIOR VIEW OF UPSTREAM LOCKKEEPER'S HOUSE, SHOWING FIRST FLOOR DINING ROOM, WITH ENTRY FRENCH DOORS IN RIGHT FOREGROUND, LOOKING NORTH - Upper Mississippi River 9-Foot Channel, Lock & Dam No. 10, Guttenberg, Clayton County, IA

  11. 5. VIEW FROM THE SOUTHEAST, LOOKING UPSTREAM (NORTHWEST), ACROSS THE ...

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

    5. VIEW FROM THE SOUTHEAST, LOOKING UPSTREAM (NORTHWEST), ACROSS THE ROADWAY OF BRIDGE 808 - Wagamon Pond Dam & Bridge, Spanning Broadkill River at State Road No. 197 (Mulberry Street), Milton, Sussex County, DE

  12. 14. VIEW NORTHEASTWARD OF THE UPSTREAM (WEST) SIDE OF THE ...

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

    14. VIEW NORTHEASTWARD OF THE UPSTREAM (WEST) SIDE OF THE PENSTOCK (HEADRACE) BRIDGE - Wagamon Pond Dam & Bridge, Spanning Broadkill River at State Road No. 197 (Mulberry Street), Milton, Sussex County, DE

  13. The electron distribution function upstream from the earth's bow shock

    NASA Technical Reports Server (NTRS)

    Cairns, Iver H.

    1987-01-01

    A general analytic theory for the distribution function of particles backstreaming from an arbitrary shock in a magnetized plasma is presented. Particle motions are shown to be restricted to two-dimensional planes. A general form for the source term describing upstreaming particles accelerated at the shock is presented along with explicit source terms for planar and parabolic shocks. The origin and form of the escape velocity cutoff for a shock in a magnetized plasma are discussed. The distribution function upstream of a finite planar shock and a parabolic shock in two dimensions is calculated, and an analytic approximation of the cutoff velocity at points in the upstream region is derived. The theory is then applied to the earth's bow shock, calculating distribution functions and the nature and spatial variation of the cutoff velocity. The theory for the particle distribution upstream of the bow shock is compared with the model of Filbert and Kellogg (1979).

  14. 2. OVERALL VIEW OF LOWWATER DAM, LOOKING UPSTREAM. CHAIN OF ...

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

    2. OVERALL VIEW OF LOW-WATER DAM, LOOKING UPSTREAM. CHAIN OF ROCKS BRIDGE AND ST. LOUIS WATER DEPARTMENT INTAKE IN BACKGROUND, LOOKING NORTHWEST - Upper Mississippi River 9-Foot Channel Project, Lock & Dam 27, Granite City, Madison County, IL

  15. 46. INTAKE DAM NO. 2, VIEW LOOKING UPSTREAM. THIS WAS ...

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

    46. INTAKE DAM NO. 2, VIEW LOOKING UPSTREAM. THIS WAS FORMERLY THE MAIN INTAKE FOR THE SYSTEM. - Kalaupapa Water Supply System, Waikolu Valley to Kalaupapa Settlement, Island of Molokai, Kalaupapa, Kalawao County, HI

  16. 10. DETAIL OF UPSTREAM FACE OF NEW YORK CANAL HEADWORKS, ...

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

    10. DETAIL OF UPSTREAM FACE OF NEW YORK CANAL HEADWORKS, SHOWING GATE LIFTING GEARS (TOP), WORM GEAR SHAFTS (CENTER) AND SLIDE GATES (BOTTOM). VIEW TO NORTHWEST. - Boise Project, Boise River Diversion Dam, Across Boise River, Boise, Ada County, ID

  17. DOG HOUSE AT UPSTREAM LOCK GATE. ALSO SEEN AT LEFT ...

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

    DOG HOUSE AT UPSTREAM LOCK GATE. ALSO SEEN AT LEFT IN PHOTO NO. IL-164-A-23. - Illinois Waterway, La Grange Lock and Dam, 3/4 mile south of Country 795N at Illinois River, Versailles, Brown County, IL

  18. UPSTREAM LOCK GATE DETAIL AND DOG HOUSE. NOTE ARM AND ...

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

    UPSTREAM LOCK GATE DETAIL AND DOG HOUSE. NOTE ARM AND GEARING FOR CONTROLLING LOCK GATE. LOOKING WEST SOUTHWEST. - Illinois Waterway, Brandon Road Lock and Dam , 1100 Brandon Road, Joliet, Will County, IL

  19. 23. UPSTREAM DETAIL OF PIER NO. 2 AND THROUGH AND ...

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

    23. UPSTREAM DETAIL OF PIER NO. 2 AND THROUGH AND DECK TRUSS END PANELS. VIEW TO SOUTHEAST. - MacArthur Bridge, Spanning Mississippi River on Highway 34 between IA & IL, Burlington, Des Moines County, IA

  20. 43. Photocopied August 1978. ICE RACK, VIEW FROM UPSTREAM, OCTOBER ...

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

    43. Photocopied August 1978. ICE RACK, VIEW FROM UPSTREAM, OCTOBER 9, 1902. NOTE TIMBERED FLOOR ABOVE RACK, THE UNTIMBERED FLOOR TO THE REAR. (284) - Michigan Lake Superior Power Company, Portage Street, Sault Ste. Marie, Chippewa County, MI

  1. 20. VIEW OF LE CLAIRE LOCK (19211925), SHOWING UPSTREAM GATES, ...

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

    20. VIEW OF LE CLAIRE LOCK (1921-1925), SHOWING UPSTREAM GATES, DOWNSTREAM SIDE AND SOUTH LOCKWALL - Mississippi River 9-Foot Channel, Lock & Dam No. 14, Upper Mississippi River, Le Claire, Scott County, IA

  2. EVALUATING THE EFFECT OF UPSTREAM WATERSHED ACTIVITIES TO DOWNSTREAM STREAMFLOW

    EPA Science Inventory

    Linking the impacts of upstream activities such as urban development to changes in downstream streamflow is critical to achieving a balance between economic development and environmental protection as a basis for sustainable watershed development. This paper presents a modeling a...

  3. 11. OBLIQUE VIEW OF BRIDGE, LOOKING SOUTHEAST OF UPSTREAM SIDE ...

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

    11. OBLIQUE VIEW OF BRIDGE, LOOKING SOUTHEAST OF UPSTREAM SIDE OF BRIDGE FROM YOLO COUNTY SIDE OF SACRAMENTO RIVER - Sacramento River Bridge, Spanning Sacramento River at California State Highway 275, Sacramento, Sacramento County, CA

  4. 3. CONTEXTUAL VIEW FROM UPSTREAM OF BRIDGE IN ITS SETTING, ...

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

    3. CONTEXTUAL VIEW FROM UPSTREAM OF BRIDGE IN ITS SETTING, LOOKING SOUTHWEST FROM ROOF OF CALIFORNIA STATE RAILROAD MUSEUM - Sacramento River Bridge, Spanning Sacramento River at California State Highway 275, Sacramento, Sacramento County, CA

  5. 7. DETAIL CENTRAL PIER (SKEWBACK) WITH BREAKWATER, UPSTREAM (EAST) SIDE. ...

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

    7. DETAIL CENTRAL PIER (SKEWBACK) WITH BREAKWATER, UPSTREAM (EAST) SIDE. NOTE FRACTURES ALONG BARREL ARCH EXTRADOS. - Roaring Creek Bridge, State Road 2005 spanning Roaring Creek in Locust Township, Slabtown, Columbia County, PA

  6. 16. VIEW EASTERLY ALONG THE UPSTREAM SIDE OF THE OGEE ...

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

    16. VIEW EASTERLY ALONG THE UPSTREAM SIDE OF THE OGEE SECTION OF THE SPILLWAY.... Volume XVIII, No. 13, January 29, 1940. - Prado Dam, Spillway, Santa Ana River near junction of State Highways 71 & 91, Corona, Riverside County, CA

  7. 26. UPSTREAM VIEW OF DISCHARGE END OF OUTLET STRUCTURE.... Volume ...

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

    26. UPSTREAM VIEW OF DISCHARGE END OF OUTLET STRUCTURE.... Volume XVI, No. 17, September 29, 1939. - Prado Dam, Outlet Works, Santa Ana River near junction of State Highways 71 & 91, Corona, Riverside County, CA

  8. 24. UPSTREAM VIEW OF A PORTION OF THE CLOSED CONDUIT ...

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

    24. UPSTREAM VIEW OF A PORTION OF THE CLOSED CONDUIT SECTION OF OUTLET WORKS.... Volume XVI, No. 15, August 16, 1939. - Prado Dam, Outlet Works, Santa Ana River near junction of State Highways 71 & 91, Corona, Riverside County, CA

  9. 7. VIEW WEST ALONG THE UPSTREAM SLOPE OF THE EMBANKMENT, ...

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

    7. VIEW WEST ALONG THE UPSTREAM SLOPE OF THE EMBANKMENT, SHOWING ROCK PAVING IN PROGRESS.... Volume XIX, No. 7, June 24, 1940. - Prado Dam, Embankment, Santa Ana River near junction of State Highways 71 & 91, Corona, Riverside County, CA

  10. 22. UPSTREAM VIEW OF THE OUTLET CONTROL STRUCTURE AND THE ...

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

    22. UPSTREAM VIEW OF THE OUTLET CONTROL STRUCTURE AND THE PIER FOR THE SERVICE BRIDGE.... Volume XVIII, No. 12, January 29, 1940. - Prado Dam, Outlet Works, Santa Ana River near junction of State Highways 71 & 91, Corona, Riverside County, CA

  11. 14. Detail, upper chord connection point on upstream side of ...

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

    14. Detail, upper chord connection point on upstream side of truss, showing connection of upper chord, laced vertical compression member, strut, counters, and laterals. - Dry Creek Bridge, Spanning Dry Creek at Cook Road, Ione, Amador County, CA

  12. 15. OVERALL VIEW OF UPSTREAM FACE OF LIFT GATE SECTION ...

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

    15. OVERALL VIEW OF UPSTREAM FACE OF LIFT GATE SECTION WITH TAINTER GATE SECTION OF SPILLWAY TO THE LEFT. VIEW TO SOUTHWEST. - Starved Rock Locks & Dam, Illinois Waterway River mile 231, Peru, La Salle County, IL

  13. 10. UPSTREAM SIDE OF UPPER MITER GATES SHOWING STOWED LEFT ...

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

    10. UPSTREAM SIDE OF UPPER MITER GATES SHOWING STOWED LEFT WING OF UPPER GUARD GATE (FAR LEFT). VIEW TO NORTHWEST. - Starved Rock Locks & Dam, Illinois Waterway River mile 231, Peru, La Salle County, IL

  14. 1. OVERALL VIEW OF UPSTREAM FACE OF DAM; SPILLWAY IN ...

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

    1. OVERALL VIEW OF UPSTREAM FACE OF DAM; SPILLWAY IN FOREGROUND, LOCK IN BACKGROUND ON NORTH RIVER BANK. VIEW TO NORTH. - Starved Rock Locks & Dam, Illinois Waterway River mile 231, Peru, La Salle County, IL

  15. 7. Detail view of reinforced concrete archrings comprising dam's upstream ...

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

    7. Detail view of reinforced concrete arch-rings comprising dam's upstream face. Impressions of the wooden formwork used in construction are visible in the concrete. - Little Rock Creek Dam, Little Rock Creek, Littlerock, Los Angeles County, CA

  16. View of upstream face of Lake Sabrina Dam showing the ...

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

    View of upstream face of Lake Sabrina Dam showing the redwood planks and base of dam from Lake Sabrina Basin, view north - Bishop Creek Hydroelectric System, Plant 2, Lake Sabrina Dam, Bishop Creek, Bishop, Inyo County, CA

  17. View of upstream face of Lake Sabrina Dam showing redwood ...

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

    View of upstream face of Lake Sabrina Dam showing redwood planks and boulders in Lake Sabrina Basin, view north - Bishop Creek Hydroelectric System, Plant 2, Lake Sabrina Dam, Bishop Creek, Bishop, Inyo County, CA

  18. View of Lake Sabrina Dam upstream face from ridge showing ...

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

    View of Lake Sabrina Dam upstream face from ridge showing spillway at lower right of photo, view southwest - Bishop Creek Hydroelectric System, Plant 2, Lake Sabrina Dam, Bishop Creek, Bishop, Inyo County, CA

  19. 4. SPILLWAY DRUM GATES AND CHANNEL, LOOKING NORTHEAST (upstream face ...

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

    4. SPILLWAY DRUM GATES AND CHANNEL, LOOKING NORTHEAST (upstream face and Control House in background) - Tieton Dam, Spillway & Drum Gates, South & East side of State Highway 12, Naches, Yakima County, WA

  20. VIEW OF COLUMBIA SOUTHERN CANAL (UPSTREAM) AND THE WEST BRANCH ...

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

    VIEW OF COLUMBIA SOUTHERN CANAL (UPSTREAM) AND THE WEST BRANCH COLUMBIA SOUTHERN CANAL DIVERSION STRUCTURE. LOOKING SOUTHWEST - Tumalo Irrigation District, Tumalo Project, West of Deschutes River, Tumalo, Deschutes County, OR

  1. VIEW OF BEGINNING (UPSTREAM) OF THE COLUMBIA SOUTHERN CANAL'S "BIG ...

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

    VIEW OF BEGINNING (UPSTREAM) OF THE COLUMBIA SOUTHERN CANAL'S "BIG CUT" BETWEEN CONSTRUCTION CAMP ROCK FEATURE AND THE COLUMBIA SOUTHERN DIVERSION STRUCTURE. LOOKING SOUTH/SOUTHEAST - Tumalo Irrigation District, Tumalo Project, West of Deschutes River, Tumalo, Deschutes County, OR

  2. View of upstream face of Grand Coulee Dam, looking west. ...

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

    View of upstream face of Grand Coulee Dam, looking west. - Columbia Basin Project, Grand Coulee Dam & Franklin D. Roosevelt Lake, Across Columbia River, Southeast of Town of Grand Coulee, Grand Coulee, Grant County, WA

  3. View of upstream face of Grand Coulee Dam, looking northeast ...

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

    View of upstream face of Grand Coulee Dam, looking northeast from the Pumping Plant. - Columbia Basin Project, Grand Coulee Dam & Franklin D. Roosevelt Lake, Across Columbia River, Southeast of Town of Grand Coulee, Grand Coulee, Grant County, WA

  4. View of upstream face of Grand Coulee Dam, looking northeast. ...

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

    View of upstream face of Grand Coulee Dam, looking northeast. This image features a cloudless sky.) - Columbia Basin Project, Grand Coulee Dam & Franklin D. Roosevelt Lake, Across Columbia River, Southeast of Town of Grand Coulee, Grand Coulee, Grant County, WA

  5. 51. VIEW, LOOKING UPSTREAM, SHOWING THE REINFORCING FOR APRON BELOW ...

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

    51. VIEW, LOOKING UPSTREAM, SHOWING THE REINFORCING FOR APRON BELOW MAIN LOCK Photograph No. 1856. December 22, 1936 - Upper Mississippi River Nine-Foot Channel Project, Lock & Dam No. 25, Cap au Gris, Lincoln County, MO

  6. 8. VIEW LOOKING UPSTREAM FROM THE RIVER ARM OF THE ...

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

    8. VIEW LOOKING UPSTREAM FROM THE RIVER ARM OF THE COFFERDAM NEAR STATION (September 1936) - Mississippi River 9-Foot Channel Project, Lock & Dam No. 13, Upper Mississippi River, Fulton, Whiteside County, IL

  7. STEEL ERECTION. View of upstream side of bridge, looking north ...

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

    STEEL ERECTION. View of upstream side of bridge, looking north from the old suspension bridge at unjoined cantilever arms - South Fork Trinity River Bridge, State Highway 299 spanning South Fork Trinity River, Salyer, Trinity County, CA

  8. 23. VIEW LOOKING UPSTREAM FROM WEST BANK OF HEADRACE SHOWING ...

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

    23. VIEW LOOKING UPSTREAM FROM WEST BANK OF HEAD-RACE SHOWING RECONSTRUCTED MAIN AND DIVERSION DAMS; HEAD-RACE IS JUST OUT OF PICTURE AT LEFT. - Forge Creek Dam-John Cable Mill, Townsend, Blount County, TN

  9. DETAIL ELEVATION OF UPSTREAM PARAPET. NOTE THE CLOSED SPANDRELS WHERE ...

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

    DETAIL ELEVATION OF UPSTREAM PARAPET. NOTE THE CLOSED SPANDRELS WHERE THE BEAM BEARINGS CONTACT THE SLENDER CONCRETE PIERS. VIEW FACING SOUTH. - Waikele Canal Bridge and Highway Overpass, Farrington Highway and Waikele Stream, Waipahu, Honolulu County, HI

  10. 65. VIEW LOOKING UPSTREAM FROM FLUME SUBSTRUCTURE, SHOWING COLUMBIA IMPROVEMENT ...

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

    65. VIEW LOOKING UPSTREAM FROM FLUME SUBSTRUCTURE, SHOWING COLUMBIA IMPROVEMENT COMPANY'S NEISSON CREEK SAWMILL. Print No. 177, November 1903 - Electron Hydroelectric Project, Along Puyallup River, Electron, Pierce County, WA

  11. 18. VIEW OF SETTLING BASIN FROM UPSTREAM TRESTLE, SHOWING BULKHEAD ...

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

    18. VIEW OF SETTLING BASIN FROM UPSTREAM TRESTLE, SHOWING BULKHEAD ON RIGHT AND SAND BANK ON LEFT, LOOKING NORTHWEST - Electron Hydroelectric Project, Along Puyallup River, Electron, Pierce County, WA

  12. 6. CREST ROAD ON UPPER EMBANKMENT, SHOWING MASONRY UPSTREAM PARAPET ...

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

    6. CREST ROAD ON UPPER EMBANKMENT, SHOWING MASONRY UPSTREAM PARAPET WALL (LEFT) AND ENTRANCE TO DEER FLAT NAMPA CANAL HEADWORKS (ALSO LEFT). VIEW TO WEST. - Boise Project, Deer Flat Embankments, Lake Lowell, Nampa, Canyon County, ID

  13. 3. General view of upstream face, looking northwest. Spillway is ...

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

    3. General view of upstream face, looking northwest. Spillway is at the far end of the dam. The Antelope Valley is visible in center background. - Little Rock Creek Dam, Little Rock Creek, Littlerock, Los Angeles County, CA

  14. 2. VIEW OF MAIN STORAGE RESERVOIR, SHOWING UPSTREAM SIDE OF ...

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

    2. VIEW OF MAIN STORAGE RESERVOIR, SHOWING UPSTREAM SIDE OF DAM AND DISCHARGE GATE (LEFT), LOOKING SOUTHWEST (October 1991) - Bonanza Hydraulic Mining Site, Main Storage Reservoir, Swamp Gulch, Salmon, Lemhi County, ID

  15. 6. GENERAL EXTERIOR VIEW LOOKING SOUTHWEST, SHOWING UPSTREAM FACE OF ...

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

    6. GENERAL EXTERIOR VIEW LOOKING SOUTHWEST, SHOWING UPSTREAM FACE OF DAM/SPILLWAY; FOLIAGE IN FOREGROUND IS ON WASHINGTON SHORELINE. - Bonneville Project, Bonneville Dam, Columbia River, Bonneville, Multnomah County, OR

  16. 10. GENERAL EXTERIOR VIEW LOOKING SOUTH, SHOWING UPSTREAM FACE OF ...

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

    10. GENERAL EXTERIOR VIEW LOOKING SOUTH, SHOWING UPSTREAM FACE OF DAM/SPILLWAY; ELECTRICALLY-OPERATED GATE MECHANISMS ARE ON RIGHT; GANTRY CRANES ARE VISIBLE IN CENTER/LEFT. - Bonneville Project, Bonneville Dam, Columbia River, Bonneville, Multnomah County, OR

  17. 6. VIEW OF UPSTREAM FACE OF HORSE MESA, SHOWING CONCRETE ...

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

    6. VIEW OF UPSTREAM FACE OF HORSE MESA, SHOWING CONCRETE BEING PLACED. PENSTOCK OPENINGS ARE VISIBLE AT CENTER LEFT. August 24, 1926 - Horse Mesa Dam, Salt River, 65 miles East of Phoenix, Phoenix, Maricopa County, AZ

  18. 7. Chandler Falls, looking upstream (from north). Golf tee of ...

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

    7. Chandler Falls, looking upstream (from north). Golf tee of the Mesa Country Club on right. Photographer: Mark Durben, February 1989. Source: SRPA - Tempe Canal, South Side Salt River in Tempe, Mesa & Phoenix, Tempe, Maricopa County, AZ

  19. 1. UPSTREAM VIEW OF THE SOUTH CHANNEL DAM, LOOKING EAST. ...

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

    1. UPSTREAM VIEW OF THE SOUTH CHANNEL DAM, LOOKING EAST. - Washington Water Power Company Post Falls Power Plant, South Channel Dam, West of intersection of Spokane & Fourth Streets, Post Falls, Kootenai County, ID

  20. 56. Upstream face of diversion dam looking east. Headgates are ...

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

    56. Upstream face of diversion dam looking east. Headgates are partially visible at far left. Photographer Mark Durben, 1986. Source: Salt River Project. - Waddell Dam, On Agua Fria River, 35 miles northwest of Phoenix, Phoenix, Maricopa County, AZ

  1. 30. Upstream face of construction effort. Photographer unknown, January 29, ...

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

    30. Upstream face of construction effort. Photographer unknown, January 29, 1927. Source: Fritz Seifritz. - Waddell Dam, On Agua Fria River, 35 miles northwest of Phoenix, Phoenix, Maricopa County, AZ

  2. 23. Upstream view of buttress and arch form work and ...

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

    23. Upstream view of buttress and arch form work and construction. Photographer unknown, 1927. Source: MWD. - Waddell Dam, On Agua Fria River, 35 miles northwest of Phoenix, Phoenix, Maricopa County, AZ

  3. 19. Upstream face of arches and buttresses at west end. ...

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

    19. Upstream face of arches and buttresses at west end. Photographer unknown, January 29, 1927. Source: MWD. - Waddell Dam, On Agua Fria River, 35 miles northwest of Phoenix, Phoenix, Maricopa County, AZ

  4. 41. Upstream end of emergency spillway excavation. Photographer unknown, 1929. ...

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

    41. Upstream end of emergency spillway excavation. Photographer unknown, 1929. Source: Arizona Department of Water Resources (ADWR). - Waddell Dam, On Agua Fria River, 35 miles northwest of Phoenix, Phoenix, Maricopa County, AZ

  5. 50. Upstream face of Humbug Creek Diversion Dam showing sluice ...

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

    50. Upstream face of Humbug Creek Diversion Dam showing sluice opening. Photographer James Eastwood, 1986. Source: Salt River Project. - Waddell Dam, On Agua Fria River, 35 miles northwest of Phoenix, Phoenix, Maricopa County, AZ

  6. 11. Close up view of construction on the upstream face. ...

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

    11. Close up view of construction on the upstream face. Photographer unknown, October 15, 1924. Source: Salt River Project. - Mormon Flat Dam, On Salt River, Eastern Maricopa County, east of Phoenix, Phoenix, Maricopa County, AZ

  7. Oscillation of circular shock waves with upstream nonuniformity

    NASA Astrophysics Data System (ADS)

    Park, Myeong-Kwan; Oshima, Shuzo; Yamane, Ryuichiro

    1992-01-01

    Up to previous reports by Park et al. on the oscillation of the circular shock waves, the investigations have been concerned with situations where the upstream flow is uniform, and oscillation and deformation were induced by only downstream conditions. But in the centrifugal diffuser of a centrifugal compressor, the flow into the diffuser becomes nonuniform due to the impeller wake and the stall in the upstream impeller, which causes deformation and oscillation of the shock wave. Here, the above effects are considered, and the upstream disturbance is generated by cylindrical bars. The imperfect circular shock wave was induced by the effect of the wake, and the oscillation state, along with the oscillation modes caused by forced oscillation, is investigated experimentally. It was found that the basic mode of the oscillation is predominant and that the oscillation is weaker than in the case of uniform upstream.

  8. 75. PALMDALE WATER COMPANY, LITTLEROCK DAM, EASTWOOD MULTIPLEARCHED TYPE: UPSTREAM ...

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

    75. PALMDALE WATER COMPANY, LITTLEROCK DAM, EASTWOOD MULTIPLE-ARCHED TYPE: UPSTREAM ELEVATION, SHEET 2; OCTOBER 2, 1919. Littlerock Water District files. - Little Rock Creek Dam, Little Rock Creek, Littlerock, Los Angeles County, CA

  9. Particles and waves Upstream of ICME Driven Interplanetary Shocks

    NASA Astrophysics Data System (ADS)

    Kajdic, P.; Blanco-Cano, X.; Aguilar-Rodriguez, E.; Russell, C. T.; Jian, L.; Opitz, A.; Luhmann, J. G.; Galvin, A. B.

    2011-12-01

    We use STEREO data to study interplanetary shocks driven by coronal mass ejections. We have found ultra-low frequency (ULF, f ~ 0.01 - 0.2 Hz) waves and high-frequency (HF, f ~ 1 Hz) fluctuations in regions upstream and downstream of these shocks. Some of the upstream HF fluctuations were classified as whistler waves. In the past whistler origin has been explained in terms of shock generation. The variety of waves found in the studied regions suggests that some of them may be generated by particle populations (electrons, ions) that can be unstable to different types of instabilities. In this work we study ions and electrons in regions immediately upstream of ten IP shocks of our sample. We use the STEREO SWEA data for electrons and STEREO PLASTIC data for ions. We study particle distributions in different points upstream of the shocks (anisotropies, temperatures, etc.) and investigate which of the observed waves can be generated by backstreaming particles.

  10. GENERAL VIEW OF CHECK DAM (UPSTREAM SIDE), CONCRETE LINED TUMALO ...

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

    GENERAL VIEW OF CHECK DAM (UPSTREAM SIDE), CONCRETE LINED TUMALO RESERVOIR FEED CANAL, AND UPPER TUMALO RESERVOIR (IN BACKGROUND) NEAR COLLINS ROAD. LOOKING WEST - Tumalo Irrigation District, Tumalo Project, West of Deschutes River, Tumalo, Deschutes County, OR

  11. Advection of Microphysical Scalars in Terminal Area Simulation System (TASS)

    NASA Technical Reports Server (NTRS)

    Ahmad, Nashat N.; Proctor, Fred H.

    2011-01-01

    The Terminal Area Simulation System (TASS) is a large eddy scale atmospheric flow model with extensive turbulence and microphysics packages. It has been applied successfully in the past to a diverse set of problems ranging from prediction of severe convective events (Proctor et al. 2002), tracking storms and for simulating weapons effects such as the dispersion and fallout of fission debris (Bacon and Sarma 1991), etc. More recently, TASS has been used for predicting the transport and decay of wake vortices behind aircraft (Proctor 2009). An essential part of the TASS model is its comprehensive microphysics package, which relies on the accurate computation of microphysical scalar transport. This paper describes an evaluation of the Leonard scheme implemented in the TASS model for transporting microphysical scalars. The scheme is validated against benchmark cases with exact solutions and compared with two other schemes - a Monotone Upstream-centered Scheme for Conservation Laws (MUSCL)-type scheme after van Leer and LeVeque's high-resolution wave propagation method. Finally, a comparison between the schemes is made against an incident of severe tornadic super-cell convection near Del City, Oklahoma.

  12. Emergence of Upstream Swimming via a Hydrodynamic Transition

    NASA Astrophysics Data System (ADS)

    Tung, Chih-kuan; Ardon, Florencia; Roy, Anubhab; Koch, Donald L.; Suarez, Susan S.; Wu, Mingming

    2015-03-01

    We demonstrate that upstream swimming of sperm emerges via an orientation disorder-order transition. The order parameter, the average orientation of the sperm head against the flow, follows a 0.5 power law with the deviation from the critical flow shear rate (γ -γc ). This transition is successfully explained by a hydrodynamic bifurcation theory, which extends the sperm upstream swimming to a broad class of near surface microswimmers that possess front-back asymmetry and circular motion.

  13. Clay with Desiccation Cracks is an Advection Dominated Environment

    NASA Astrophysics Data System (ADS)

    Baram, S.; Kurtzman, D.; Sher, Y.; Ronen, Z.; Dahan, O.

    2012-04-01

    , indicating deep soil evaporation. Daily fluctuation of the air temperature in the desiccation cracks supported thermally induced air convection within the cracks void and could explain the deep soil salinization process. Combination of all the abovementioned observations demonstrated that the formation of desiccation cracks network in dispersive clay sediments generates a bulk advection dominated environment for both air and water flow, and that the reference to clay sediments as "hydrologically safe" should to be reconsidered.

  14. Black Hole Event Horizons and Advection-Dominated Accretion

    NASA Technical Reports Server (NTRS)

    McClintock, Jeffrey; Mushotzky, Richard F. (Technical Monitor)

    2001-01-01

    The XMM data on black-hole X-ray novae are only now becoming available and they have so far not been included in any publications. This work is part of a larger project that makes use of both XMM and Chandra data. Our first publication on the Chandra results is the following: "New Evidence for Black Hole Event Horizons from Chandra" by M.R. Garcia, J.E. McClintock, R. Narayan, P. Callanan, D. Barret and S. Murray (2001, ApJ, 553, L47). Therein we present the luminosities of the two black-hole X-ray novae, GRO J0422+22 and 4U1 543-47, which were observed by Chandra. These results are combined with the luminosities of four additional black-hole X-ray novae, which were observed as part of a Chandra GTO program (PI: S. Murray). The very low, but nonzero, quiescent X-ray luminosities of these black hole binaries is very difficult to understand in the context of standard viscous accretion disk theory. The principal result of this work is that X-ray novae that contain black hole primaries are about 100 times fainter that X-ray novae that contain neutron star primaries. This result had been suggested in earlier work, but the present work very firmly establishes this large luminosity difference. The result is remarkable because the black-hole and the neutron-star systems are believed to be similar in many respects. Most importantly, the mass transfer rate from the secondary star is believed to be very comparable for the two kinds of systems for similar orbital periods. The advection-dominated accretion flow (ADAF) model provides a natural framework for understanding the extraordinarily low luminosities of the black hole systems and the hundred-fold greater luminosities of the neutron star systems. The chief feature of an ADAF is that the heat energy in the accreting gas is trapped in the gas and travels with it, rather than being radiated promptly. Thus the accreting gas reaches the central object with a huge amount of thermal energy. If the accretor is a black hole, the

  15. The Split-Stem Technique

    ERIC Educational Resources Information Center

    Carter, Roy A.

    1972-01-01

    Describes a procedure useful for investigating the effects of substances on plant growth and development. A bean seedling's stem is partially split, and each half is placed in a different nutrient solution. Suggestions for the instructional use of the technique are made. (AL)

  16. AN EXACT PEAK CAPTURING AND OSCILLATION-FREE SCHEME TO SOLVE ADVECTION-DISPERSION TRANSPORT EQUATIONS

    EPA Science Inventory

    An exact peak capturing and essentially oscillation-free (EPCOF) algorithm, consisting of advection-dispersion decoupling, backward method of characteristics, forward node tracking, and adaptive local grid refinement, is developed to solve transport equations. This algorithm repr...

  17. Fast Coherent Particle Advection through Time-Varying Unstructured Flow Datasets.

    PubMed

    Chen, Mingcheng; Shadden, Shawn C; Hart, John C

    2016-08-01

    Tracing the paths of collections of particles through a flow field is a key step for many flow visualization and analysis methods. When a flow field is interpolated from the nodes of an unstructured mesh, the process of advecting a particle must first find which cell in the unstructured mesh contains the particle. Since the paths of nearby particles often diverge, the parallelization of particle advection quickly leads to incoherent memory accesses of the unstructured mesh. We have developed a new block advection GPU approach that reorganizes particles into spatially coherent bundles as they follow their advection paths, which greatly improves memory coherence and thus shared-memory GPU performance. This approach works best for flows that meet the CFL criterion on unstructured meshes of uniformly sized elements, small enough to fit at least two timesteps in GPU memory. PMID:26353375

  18. Finite element approximation of large air pollution problems. I. Advection. Technical report, January-March 1995

    SciTech Connect

    Giraldo, F.X.; Neta, B.

    1995-04-21

    An Eulerian and semi-Lagrangian finite element methods for the solution of the two dimensional advection equation were developed. Bilinear rectangular elements were used. Linear stability analysis of the method is given.

  19. Sensitivity of Gcm Inm Ras To The Change of Humidity Advection Scheme

    NASA Astrophysics Data System (ADS)

    Kostrykin, S. V.

    We study the influence of change the numerical scheme used for humidity advection in the GCM INM RAS on the model results. The previously used advection scheme of the second order ­ leap-frog was changed on the semi-lagrangian cip scheme of the third order. It has shown that the last scheme has excelent numerical properties among other common semi-lagrangian schemes dealing with precise advection of sharp gra- dients. The numerical expriments with GCM has shown that the main changes in the humidity and temperature fields has happend near tropopause. More closeness of the model fields obtained with new advection of humidity to the NCAR/NCEP reanalyses fields are shown.

  20. A Quasi-Conservative Adaptive Semi-Lagrangian Advection-Diffusion Scheme

    NASA Astrophysics Data System (ADS)

    Behrens, Joern

    2014-05-01

    Many processes in atmospheric or oceanic tracer transport are conveniently represented by advection-diffusion type equations. Depending on the magnitudes of both components, the mathematical representation and consequently the discretization is a non-trivial problem. We will focus on advection-dominated situations and will introduce a semi-Lagrangian scheme with adaptive mesh refinement for high local resolution. This scheme is well suited for pollutant transport from point sources, or transport processes featuring fine filamentation with corresponding local concentration maxima. In order to achieve stability, accuracy and conservation, we combine an adaptive mesh refinement quasi-conservative semi-Lagrangian scheme, based on an integral formulation of the underlying advective conservation law (Behrens, 2006), with an advection diffusion scheme as described by Spiegelman and Katz (2006). The resulting scheme proves to be conservative and stable, while maintaining high computational efficiency and accuracy.

  1. Comparison of thermal advection measurements by clear-air radar and radiosonde techniques

    SciTech Connect

    Crochet, M.; Rougier, G.; Bazile, G. Meteorologie Nationale, Trappes )

    1990-10-01

    Vertical profiles of the horizontal wind have been measured every 4 min by a clear-air radar (stratospheric-troposphere radar), and vertical profiles of temperature have been obtained every 2 hours by three radiosonde soundings in the same zone in Brittany during the Mesoscale Frontal Dynamics Project FRONTS 87 campaign. Radar thermal advection is deduced from the thermal wind equation using the measured real horizontal wind instead of the geostrophic wind. Radiosonde thermal advection is determined directly from the sounding station data sets of temperature gradients and also approximately from the thermodynamic equation by the temperature tendency. These approximations, applied during a frontal passage, show the same general features and magnitude of the thermal advection, giving a preliminary but encouraging conclusion for a possible real-time utilization of clear-air radars to monitor thermal advection and to identify its characteristic features. 6 refs.

  2. The impact of advection on stratification and chlorophyll variability in the equatorial Pacific

    NASA Astrophysics Data System (ADS)

    Dave, Apurva C.; Lozier, M. Susan

    2015-06-01

    Previously reported global-scale correlations between interannual variability in upper ocean stratification and chlorophyll a (a proxy for phytoplankton biomass) have been shown to be driven by strong associations between the two properties in the central and western equatorial Pacific. Herein, we present evidence that these correlations are not causal but instead result from the advection of heat, salt, and nutrients in the region. Specifically, we demonstrate that stratification and chlorophyll are simultaneously influenced by shifts in the horizontal advective inputs of cold/saline/nutrient-rich waters from upwelling regions to the east and warm/fresh/nutrient-poor waters to the west. We find that horizontal advection contributes substantially to the annual surface layer nutrient budget and, together with vertical advection, significantly impacts interannual variability in chlorophyll. These results highlight the importance of a three-dimensional framework for examining nutrient supply in the upper ocean—a crucial requirement for assessing future marine ecosystem responses to a changing climate.

  3. A fully implicit method for 3D quasi-steady state magnetic advection-diffusion.

    SciTech Connect

    Siefert, Christopher; Robinson, Allen Conrad

    2009-09-01

    We describe the implementation of a prototype fully implicit method for solving three-dimensional quasi-steady state magnetic advection-diffusion problems. This method allows us to solve the magnetic advection diffusion equations in an Eulerian frame with a fixed, user-prescribed velocity field. We have verified the correctness of method and implementation on two standard verification problems, the Solberg-White magnetic shear problem and the Perry-Jones-White rotating cylinder problem.

  4. Advection-Induced Spectrotemporal Defects in a Free-Electron Laser

    SciTech Connect

    Bielawski, S.; Szwaj, C.; Bruni, C.; Garzella, D.; Orlandi, G.L.; Couprie, M.E.

    2005-07-15

    We evidence numerically and experimentally that advection can induce spectrotemporal defects in a system presenting a localized structure. Those defects in the spectrum are associated with the breakings induced by the drift of the localized solution. The results are based on simulations and experiments performed on the super-ACO free-electron laser. However, we show that this instability can be generalized using a real Ginzburg-Landau equation with (i) advection and (ii) a finite-size supercritical region.

  5. Spectral approximation to advection-diffusion problems by the fictitious interface method

    NASA Astrophysics Data System (ADS)

    Frati, A.; Pasquarelli, F.; Quarteroni, A.

    1993-08-01

    The algorithmic aspects of the 'fictitious interface' method used in numerical approximations of convection-dominated flows are discussed. The solution algorithm presented alternates the advection-equation solution with that of the advection-diffusion equation within complementary subdomains. For the problems presently considered, spatial discretization is obtained by the spectral collocation method via Legendre-Gaussian modes. Attention is given to the the fictitious interface method's application to the Burgers equation.

  6. Cool covered sky-splitting spectrum-splitting FK

    SciTech Connect

    Mohedano, Rubén; Chaves, Julio; Falicoff, Waqidi; Hernandez, Maikel; Sorgato, Simone; Miñano, Juan C.; Benitez, Pablo; Buljan, Marina

    2014-09-26

    Placing a plane mirror between the primary lens and the receiver in a Fresnel Köhler (FK) concentrator gives birth to a quite different CPV system where all the high-tech components sit on a common plane, that of the primary lens panels. The idea enables not only a thinner device (a half of the original) but also a low cost 1-step manufacturing process for the optics, automatic alignment of primary and secondary lenses, and cell/wiring protection. The concept is also compatible with two different techniques to increase the module efficiency: spectrum splitting between a 3J and a BPC Silicon cell for better usage of Direct Normal Irradiance DNI, and sky splitting to harvest the energy of the diffuse radiation and higher energy production throughout the year. Simple calculations forecast the module would convert 45% of the DNI into electricity.

  7. Barriers impede upstream spawning migration of flathead chub

    USGS Publications Warehouse

    Walters, David M.; Zuellig, Robert E.; Crockett, Harry J.; Bruce, James F.; Lukacs, Paul M.; Fitzpatrick, Ryan M.

    2014-01-01

    Many native cyprinids are declining throughout the North American Great Plains. Some of these species require long reaches of contiguous, flowing riverine habitat for drifting eggs or larvae to develop, and their declining populations have been attributed to habitat fragmentation or barriers (e.g., dams, dewatered channels, and reservoirs) that restrict fish movement. Upstream dispersal is also needed to maintain populations of species with passively drifting eggs or larvae, and prior researchers have suggested that these fishes migrate upstream to spawn. To test this hypothesis, we conducted a mark–recapture study of Flathead Chub Platygobio gracilis within a 91-km reach of continuous riverine habitat in Fountain Creek, Colorado. We measured CPUE, spawning readiness (percent of Flathead Chub expressing milt), and fish movement relative to a channel-spanning dam. Multiple lines of evidence indicate that Flathead Chub migrate upstream to spawn during summer. The CPUE was much higher at the base of the dam than at downstream sites; the seasonal increases in CPUE at the dam closely tracked seasonal increases in spawning readiness, and marked fish moved upstream as far as 33 km during the spawning run. The upstream migration was effectively blocked by the dam. The CPUE of Flathead Chub was much lower upstream of the OHDD than at downstream sites, and <0.2% of fish marked at the dam were recaptured upstream. This study provides the first direct evidence of spawning migration for Flathead Chub and supports the general hypothesis that barriers limit adult dispersal of these and other plains fishes.

  8. 7 CFR 51.2002 - Split shell.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ....2002 Split shell. Split shell means a shell having any crack which is open and conspicuous for a distance of more than one-fourth the circumference of the shell, measured in the direction of the crack....

  9. Stability of split Stirling refrigerators

    NASA Astrophysics Data System (ADS)

    de Waele, A. T. A. M.; Liang, W.

    2009-02-01

    In many thermal systems spontaneous mechanical oscillations are generated under the influence of large temperature gradients. Well-known examples are Taconis oscillations in liquid-helium cryostats and oscillations in thermoacoustic systems. In split Stirling refrigerators the compressor and the cold finger are connected by a flexible tube. The displacer in the cold head is suspended by a spring. Its motion is pneumatically driven by the pressure oscillations generated by the compressor. In this paper we give the basic dynamic equations of split Stirling refrigerators and investigate the possibility of spontaneous mechanical oscillations if a large temperature gradient develops in the cold finger, e.g. during or after cool down. These oscillations would be superimposed on the pressure oscillations of the compressor and could ruin the cooler performance.

  10. Health and safety in small workplaces: refocusing upstream.

    PubMed

    Eakin, Joan M; Champoux, Danièle; MacEachen, Ellen

    2010-01-01

    Small workplaces have particular injury risks and are enduringly difficult for the occupational health and safety (OHS) system to reach. This paper puts forward an "upstream" perspective on OHS in small workplaces that moves beyond the attributes of the workplace and those who work there. The paper draws on and synthesizes ideas and findings from emerging upstream OHS research, our own empirical investigations in Ontario and Quebec, and our collected research experience in small workplace health. Upstream structures and processes (regulations, policies, services, interventions, professional practices) are often misaligned with the conditions of work and social relations of small workplaces. Key upstream factors include regulatory exemption, subcontracting, unionization levels, the changing character of small enterprise, joint management, service and inspection constraints, competing institutional accountabilities, institutional orientation to large business, and inappropriate service and policy. Misalignment of the OHS system with the nature and practical realities of small workplaces can undermine prevention and the management of ill health and injury. To address such misalignments, the paper calls for: 1) restructuring of data collection and consultation processes to increase the visibility, voice and credibility of small workplaces; 2) "audits" of OHS-related legislation, policy and interventions to assess and address implications for small workplaces; 3) reflection on current terms and concepts that render workers invisible and capture poorly the essence and (increasing) diversity of these workplaces; and 4) extension of the upstream gaze to the global level. PMID:20629444

  11. Testing split supersymmetry with inflation

    NASA Astrophysics Data System (ADS)

    Craig, Nathaniel; Green, Daniel

    2014-07-01

    Split supersymmetry (SUSY) — in which SUSY is relevant to our universe but largely inaccessible at current accelerators — has become increasingly plausible given the absence of new physics at the LHC, the success of gauge coupling unification, and the observed Higgs mass. Indirect probes of split SUSY such as electric dipole moments (EDMs) and flavor violation offer hope for further evidence but are ultimately limited in their reach. Inflation offers an alternate window into SUSY through the direct production of superpartners during inflation. These particles are capable of leaving imprints in future cosmological probes of primordial non-gaussianity. Given the recent observations of BICEP2, the scale of inflation is likely high enough to probe the full range of split SUSY scenarios and therefore offers a unique advantage over low energy probes. The key observable for future experiments is equilateral non-gaussianity, which will be probed by both cosmic microwave background (CMB) and large scale structure (LSS) surveys. In the event of a detection, we forecast our ability to find evidence for superpartners through the scaling behavior in the squeezed limit of the bispectrum.

  12. Split torque transmission load sharing

    NASA Technical Reports Server (NTRS)

    Krantz, T. L.; Rashidi, M.; Kish, J. G.

    1992-01-01

    Split torque transmissions are attractive alternatives to conventional planetary designs for helicopter transmissions. The split torque designs can offer lighter weight and fewer parts but have not been used extensively for lack of experience, especially with obtaining proper load sharing. Two split torque designs that use different load sharing methods have been studied. Precise indexing and alignment of the geartrain to produce acceptable load sharing has been demonstrated. An elastomeric torque splitter that has large torsional compliance and damping produces even better load sharing while reducing dynamic transmission error and noise. However, the elastomeric torque splitter as now configured is not capable over the full range of operating conditions of a fielded system. A thrust balancing load sharing device was evaluated. Friction forces that oppose the motion of the balance mechanism are significant. A static analysis suggests increasing the helix angle of the input pinion of the thrust balancing design. Also, dynamic analysis of this design predicts good load sharing and significant torsional response to accumulative pitch errors of the gears.

  13. 10 CFR 26.135 - Split specimens.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 10 Energy 1 2013-01-01 2013-01-01 false Split specimens. 26.135 Section 26.135 Energy NUCLEAR REGULATORY COMMISSION FITNESS FOR DUTY PROGRAMS Licensee Testing Facilities § 26.135 Split specimens. (a) If the FFD program follows split-specimen procedures, as described in § 26.113, the licensee...

  14. 10 CFR 26.135 - Split specimens.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 10 Energy 1 2012-01-01 2012-01-01 false Split specimens. 26.135 Section 26.135 Energy NUCLEAR REGULATORY COMMISSION FITNESS FOR DUTY PROGRAMS Licensee Testing Facilities § 26.135 Split specimens. (a) If the FFD program follows split-specimen procedures, as described in § 26.113, the licensee...

  15. 10 CFR 26.135 - Split specimens.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 10 Energy 1 2014-01-01 2014-01-01 false Split specimens. 26.135 Section 26.135 Energy NUCLEAR REGULATORY COMMISSION FITNESS FOR DUTY PROGRAMS Licensee Testing Facilities § 26.135 Split specimens. (a) If the FFD program follows split-specimen procedures, as described in § 26.113, the licensee...

  16. Influence of porewater advection on denitrification in carbonate sands: Evidence from repacked sediment column experiments

    NASA Astrophysics Data System (ADS)

    Santos, Isaac R.; Eyre, Bradley D.; Glud, Ronnie N.

    2012-11-01

    Porewater flow enhances mineralization rates in organic-poor permeable sands. Here, a series of sediment column experiments were undertaken to assess the potential effect of advective porewater transport on denitrification in permeable carbonate sands collected from Heron Island (Great Barrier Reef). Experimental conditions (flow path length, advection rate, and temperature) were manipulated to represent conditions similar to near shore tropical environments. HgCl2-poisoned controls were used to assess whether reactions were microbially mediated. Overall, significant correlations were found between oxygen consumption and N2 production. The N:O2 slope of 0.114 implied that about 75% of all the nitrogen mineralized was denitrified. A 4-fold increase in sediment column length (from 10 to 40 cm) resulted in an overall increase in oxygen consumption (1.6-fold), TCO2 production (1.8-fold), and denitrification (1.9-fold). Oxic respiration increased quickly until advection reached 80 L m-2 h-1 and then plateaued at higher advection rates. Interestingly, denitrification peaked (up to 336 μmol N2 m-2 h-1) at intermediate advection rates (30-80 L m-2 h-1). We speculate that intermediate advection rates enhance the development of microniches (i.e., steep oxygen gradients) within porous carbonate sands, perhaps providing optimum conditions for denitrification. The denitrification peak fell within the broad range of advection rates (often on scales of 1-100 L m-2 h-1) typically found on continental shelves implying that carbonate sands may play a major, but as yet unquantified, role in oceanic nitrogen budgets.

  17. Comparison of properties of upstream whistlers at different planets

    NASA Technical Reports Server (NTRS)

    Orlowski, D. S.; Russell, C. T.

    1995-01-01

    Whistler mode waves have been recorded in the upstream region of Mercury, Venus, Earth and Saturn. They are elliptically polarized and observed typically at frequencies between 0.1 to 4 Hz. These intrinsically right handed waves can be left-handed polarized in the spaceframe as a result of strong negative Doppler shift. The waves propagate at an angle between 10 and 60 deg to the background magnetic field, with (Delta B)/B rarely exceeding 0.1. Comprehensive studies of these waves at Earth and Venus indicate that upstream whistlers are generated at the shock rather than locally in the foreshock. In this paper, we compare properties of upstream whistlers at all these planets. We also discuss the utilization of selected properties of these waves to evaluate the effective Alfvenic Mach number and the shock thickness at Mercury where solar wind measurements are not available.

  18. MESSENGER Observations of Upstream Whistler Waves in Mercury's Foreshock Region

    NASA Astrophysics Data System (ADS)

    Le, G.; Chi, P. J.; Blanco-Cano, X.; Boardsen, S. A.; Slavin, J. A.; Anderson, B. J.; Korth, H.

    2012-12-01

    The region upstream from a planetary bow shock is a natural plasma laboratory containing a variety of wave particle phenomena. The study of foreshocks other than the Earth's is important for extending our understanding of collisionless shocks and foreshock physics since the bow shock strength varies with heliocentric distance from the Sun, and the sizes of the bow shocks are different at different planets. The Mercury's bow shock is unique in our solar system as it is produced by low Mach number and low plasma beta solar wind blowing over a small magnetized body with a predominately radial interplanetary magnetic field. Previous observations of Mercury upstream ultra-low frequency (ULF) waves came exclusively from two Mercury flybys of Mariner 10. The MESSENGER orbiter data enable us to study upstream waves in the Mercury's foreshock in depth. This paper reports an overview of upstream ULF waves in the Mercury's foreshock using high-time resolution magnetic field data, 20 samples per second, from the MESSENGER spacecraft. A preliminary study has shown the existence of at least three types of upstream waves: 1) whistler waves at frequencies near 2 Hz, similar to 1-Hz waves at the Earth; 2) waves with frequencies ~ 0.1 Hz, similar to the large-amplitude 30-s waves at the Earth; 3) fluctuations with broad spectral peaks centered at ~ 0.6 Hz. Unlike the Earth's foreshock where the most prominent upstream wave phenomenon is locally generated large-amplitude 30-s waves, the most common foreshock waves are whistler waves generated at the bow shock, with properties similar to the 1-Hz waves in the Earth's foreshock. These "one-Hz" waves are present in both the flyby data and in every orbit of the orbital data we have surveyed. We will discuss their properties, spatial variations, and propagation and occurrence characteristics in this paper.

  19. Transition duct with divided upstream and downstream portions

    SciTech Connect

    McMahan, Kevin Weston; LeBegue, Jeffrey Scott; Maldonado, Jaime Javier; Dillard, Daniel Jackson; Flanagan, James Scott

    2015-07-14

    Turbine systems are provided. In one embodiment, a turbine system includes a transition duct comprising an inlet, an outlet, and a duct passage extending between the inlet and the outlet and defining a longitudinal axis, a radial axis, and a tangential axis. The outlet of the transition duct is offset from the inlet along the longitudinal axis and the tangential axis. The duct passage includes an upstream portion extending from the inlet and a downstream portion extending from the outlet. The turbine system further includes a rib extending from an outer surface of the duct passage, the rib dividing the upstream portion and the downstream portion.

  20. Emergence of upstream swimming through a hydrodynamic transition

    PubMed Central

    Tung, Chih-kuan; Ardon, Florencia; Roy, Anubhab; Koch, Donald L.; Suarez, Susan S.; Wu, Mingming

    2015-01-01

    We demonstrate that upstream swimming of sperm emerges via an orientation disorder-order transition. The order parameter, the average orientation of the sperm head against the flow, follows a 0.5 power law with the deviation from the critical flow shear rate (γ − γc). This transition is successfully explained by a hydrodynamic bifurcation theory, which extends the sperm upstream swimming to a broad class of near surface micro-swimmers that possess front-back asymmetry and circular motion. PMID:25815969

  1. Split-inteins and their bioapplications.

    PubMed

    Li, Yifeng

    2015-11-01

    Split-inteins are a subset of inteins that are expressed in two separate halves and catalyze splicing in trans upon association of the two domains. They occur naturally and have also been artificially generated by splitting of contiguous ones. With their unique properties, split-inteins offer improved controllability, flexibility and capability to existing tools based on contiguous inteins. In addition, split-inteins have proven useful in several new applications. This review gives a general introduction to split-inteins with a focus on their role in expanding the applications of intein-based technologies. PMID:26153348

  2. Advection and resulting CO2 exchange uncertainty in a tall forest in central Germany.

    PubMed

    Kutsch, Werner L; Kolle, Olaf; Rebmann, Corinna; Knohl, Alexander; Ziegler, Waldemar; Schulze, Ernst-Detlef

    2008-09-01

    Potential losses by advection were estimated at Hainich Forest, Thuringia, Germany, where the tower is located at a gentle slope. Three approaches were used: (1) comparing nighttime eddy covariance fluxes to an independent value of total ecosystem respiration by bottom-up modeling of the underlying processes, (2) direct measurements of a horizontal CO2 gradient and horizontal wind speed at 2 m height in order to calculate horizontal advection, and (3) direct measurements of a vertical CO2 gradient and a three-dimensional wind profile in order to calculate vertical advection. In the first approach, nighttime eddy covariance measurements were compared to independent values of total ecosystem respiration by means of bottom-up modeling of the underlying biological processes. Turbulent fluxes and storage term were normalized to the fluxes calculated by the bottom-up model. Below a u(*) threshold of 0.6 m/s the normalized turbulent fluxes decreased with decreasing u(*), but the flux to the storage increased only up to values less than 20% of the modeled flux at low turbulence. Horizontal advection was measured by a horizontal CO2 gradient over a distance of 130 m combined with horizontal wind speed measurements. Horizontal advection occurred at most of the evenings independently of friction velocity above the canopy. Nevertheless, horizontal advection was higher when u(*) was low. The peaks of horizontal advection correlated with changes in temperature. A full mass balance including turbulent fluxes, storage, and horizontal and vertical advection resulted in an increase of spikes and scatter but seemed to generally improve the results from the flux measurements. The comparison of flux data with independent bottom-up modeling results as well as the direct measurements resulted in strong indications that katabatic flows along the hill slope during evening and night reduces the measured apparent ecosystem respiration rate. In addition, anabatic flows may occur during the

  3. Modeling of Convective-Stratiform Precipitation Processes: Sensitivity to Partitioning Methods and Numerical Advection Schemes

    NASA Technical Reports Server (NTRS)

    Lang, Steve; Tao, W.-K.; Simpson, J.; Ferrier, B.; Einaudi, Franco (Technical Monitor)

    2001-01-01

    Six different convective-stratiform separation techniques, including a new technique that utilizes the ratio of vertical and terminal velocities, are compared and evaluated using two-dimensional numerical simulations of a tropical [Tropical Ocean Global Atmosphere Coupled Ocean-Atmosphere Response Experiment (TOGA COARE)] and midlatitude continental [Preliminary Regional Experiment for STORM-Central (PRESTORM)] squall line. The simulations are made using two different numerical advection schemes: 4th order and positive definite advection. Comparisons are made in terms of rainfall, cloud coverage, mass fluxes, apparent heating and moistening, mean hydrometeor profiles, CFADs (Contoured Frequency with Altitude Diagrams), microphysics, and latent heating retrieval. Overall, it was found that the different separation techniques produced results that qualitatively agreed. However, the quantitative differences were significant. Observational comparisons were unable to conclusively evaluate the performance of the techniques. Latent heating retrieval was shown to be sensitive to the use of separation technique mainly due to the stratiform region for methods that found very little stratiform rain. The midlatitude PRESTORM simulation was found to be nearly invariant with respect to advection type for most quantities while for TOGA COARE fourth order advection produced numerous shallow convective cores and positive definite advection fewer cells that were both broader and deeper penetrating above the freezing level.

  4. Curves to determine the relative importance of advection and dispersion for solute and vapor transport

    USGS Publications Warehouse

    Garges, J.A.; Baehr, A.L.

    1998-01-01

    The relative importance of advection and dispersion for both solute and vapor transport can be determined from type curves or concentration, flux, or cumulative flux. The dimensionless form of the type curves provides a means to directly evaluate the importance of mass transport by advection relative to that of mass transport by diffusion and dispersion. Type curves based on an analytical solution to the advection-dispersion equation are plotted in terms of dimensionless time and Peclet number. Flux and cumulative flux type curves provide additional rationale for transport regime determination in addition to the traditional concentration type curves. The extension of type curves to include vapor transport with phase partitioning in the unsaturated zone is a new development. Type curves for negative Peclet numbers also are presented. A negative Peclet number characterizes a problem in which one direction of flow is toward the contamination source, and thereby diffusion and advection can act in opposite directions. Examples are the diffusion of solutes away from the downgradient edge of a pump-and-treat capture zone, the upward diffusion of vapors through the unsaturated zone with recharge, and the diffusion of solutes through a low hydraulic conductivity cutoff wall with an inward advective gradient.

  5. A Novel Electrical Model for Advection-Diffusion-Based Molecular Communication in Nanonetworks.

    PubMed

    Azadi, Mehdi; Abouei, Jamshid

    2016-04-01

    In this paper, we propose an end-to-end electrical model to characterize the communication between two nanomachines via advection-diffusion motion along the conventional pipe medium. For this modeling, we consider three modules consisting of transmitter, advection-diffusion propagation and receiver. The modulation scheme and releasing molecules through the conventional pipe medium from the transmitter nanomachine is represented in the transmitter module. The advection-diffusion propagation of molecules along the flow-induced path is shown in advection-diffusion propagation module, and the demodulation scheme of bounded particles at the receiver nanomachine is characterized in the receiver module. Our objective is to find an electrical model of each module under the zero initial condition which enables us to represent the electrical circuit related to each module. The transmitter and the signal propagation models are built on the basis of the molecular advection-diffusion physics, whereas the receiver model is interpreted by stemming from the theory of the ligand-receptor binding chemical process. In addition, we employ the transfer function of modules to derive the normalized gain and the delay of each module. Supported by numerical results, we analyze the effect of physical parameters of the pipe medium on the total normalized gain and delay of molecular communications. PMID:27046879

  6. Construction of the SILAM Eulerian atmospheric dispersion model based on the advection algorithm of Michael Galperin

    NASA Astrophysics Data System (ADS)

    Sofiev, M.; Vira, J.; Kouznetsov, R.; Prank, M.; Soares, J.; Genikhovich, E.

    2015-11-01

    The paper presents the transport module of the System for Integrated modeLling of Atmospheric coMposition SILAM v.5 based on the advection algorithm of Michael Galperin. This advection routine, so far weakly presented in the international literature, is positively defined, stable at any Courant number, and efficient computationally. We present the rigorous description of its original version, along with several updates that improve its monotonicity and shape preservation, allowing for applications to long-living species in conditions of complex atmospheric flows. The scheme is connected with other parts of the model in a way that preserves the sub-grid mass distribution information that is a cornerstone of the advection algorithm. The other parts include the previously developed vertical diffusion algorithm combined with dry deposition, a meteorological pre-processor, and chemical transformation modules. The quality of the advection routine is evaluated using a large set of tests. The original approach has been previously compared with several classic algorithms widely used in operational dispersion models. The basic tests were repeated for the updated scheme and extended with real-wind simulations and demanding global 2-D tests recently suggested in the literature, which allowed one to position the scheme with regard to sophisticated state-of-the-art approaches. The advection scheme performance was fully comparable with other algorithms, with a modest computational cost. This work was the last project of Dr. Sci. Michael Galperin, who passed away on 18 March 2008.

  7. Estimation of the advection effects induced by surface heterogeneities in the surface energy budget

    NASA Astrophysics Data System (ADS)

    Cuxart, Joan; Wrenger, Burkhard; Martínez-Villagrasa, Daniel; Reuder, Joachim; Jonassen, Marius O.; Jiménez, Maria A.; Lothon, Marie; Lohou, Fabienne; Hartogensis, Oscar; Dünnermann, Jens; Conangla, Laura; Garai, Anirban

    2016-07-01

    The effect of terrain heterogeneities in one-point measurements is a continuous subject of discussion. Here we focus on the order of magnitude of the advection term in the equation of the evolution of temperature as generated by documented terrain heterogeneities and we estimate its importance as a term in the surface energy budget (SEB), for which the turbulent fluxes are computed using the eddy-correlation method. The heterogeneities are estimated from satellite and model fields for scales near 1 km or broader, while the smaller scales are estimated through direct measurements with remotely piloted aircraft and thermal cameras and also by high-resolution modelling. The variability of the surface temperature fields is not found to decrease clearly with increasing resolution, and consequently the advection term becomes more important as the scales become finer. The advection term provides non-significant values to the SEB at scales larger than a few kilometres. In contrast, surface heterogeneities at the metre scale yield large values of the advection, which are probably only significant in the first centimetres above the ground. The motions that seem to contribute significantly to the advection term in the SEB equation in our case are roughly those around the hectometre scales.

  8. Upstream particle events close to the bow shock and 200 earth radii upstream - ISEE-1 and ISEE-3 observations

    NASA Technical Reports Server (NTRS)

    Scholer, M.; Hovestadt, D.; Klecker, B.; Ipavich, F. M.; Gloeckler, G.

    1980-01-01

    Two energetic particle events (28 keV - 145 keV) upstream of the earth's bow shock have been investigated with two identical experiments of the Max-Planck-Institut/University of Maryland on ISEE-1 and ISEE-3. Close to the bow shock the particle distribution is more or less isotropic and indicates strong scattering of these particles in the upstream wave field. At ISEE-3 the particles move essentially scatter-free from the general bow shock direction. The temporal evolution of the particle bursts is discussed in terms of the interplanetary magnetic field topology and the scattering conditions.

  9. Laser Doppler velocity measurements of swirling flows with upstream influence

    NASA Technical Reports Server (NTRS)

    Rloff, K. L.; Bossel, H. H.

    1973-01-01

    Swirling flow in a rotating tube is studied by flow visualization at a moderate Reynolds number, and its velocity field is measured by laser-Doppler anemometry. The tube has constant diameter, and approximately uniform initial rigid rotation of the flow is assured by passing the flow through a rotating plug of porous metal before it enters the test section. At moderate swirl values, an object mounted on the tube centerline causes a closed bubble to form upstream of the obstacle, with a clearly defined stagnation point on the axis, and recirculating flow inside the bubble. The bubble length grows upstream as the swirl is increased, until it breaks up into a Taylor column reaching all the way upstream and downstream at swirl values above a certain critical value. A vortex jump (in the sense of Benjamin) occurs downstream of the obstacle except when the Taylor column is present. Using a laser-Doppler anemometer, axial and swirl velocity profiles are obtained at several stations upstream and downstream of the bubble, and in and around the bubble.

  10. 9. Detail, typical bearing, upstream side of west end of ...

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

    9. Detail, typical bearing, upstream side of west end of Bridge Number 301.85, view to east, 210mm lens with electronic flash fill. - Southern Pacific Railroad Shasta Route, Bridge No. 301.85, Milepost 301.85, Pollard Flat, Shasta County, CA

  11. 9. UPSTREAM EXTENSION TO 60' INFILTRATION PIPE: REINFORCEMENT DETAILS OF ...

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

    9. UPSTREAM EXTENSION TO 60' INFILTRATION PIPE: REINFORCEMENT DETAILS OF VALVE CONTROL STRUCTURE. Sheet A-20, July, 1939. File no. SA 342/29. - Prado Dam, Embankment, Santa Ana River near junction of State Highways 71 & 91, Corona, Riverside County, CA

  12. 68. VIEW, LOOKING NORTH (UPSTREAM) FROM LOWER ARM OF COFFERDAM, ...

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

    68. VIEW, LOOKING NORTH (UPSTREAM) FROM LOWER ARM OF COFFERDAM, SHOWING STATUS OF CONSTRUCTION. NOTE CONCRETE FORMS IN DISTANCE, TIMBER PILES FOR INTERMEDIATE WALL IN CENTER, AND CONCRETE MIXING PLANT ON RIGHT. Taken September 4, 1934. - Upper Mississippi River 9-Foot Channel, Lock & Dam No. 10, Guttenberg, Clayton County, IA

  13. 23. VIEW LOOKING UPSTREAM AND TOWARD LEFT ABUTMENT OF DAM. ...

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

    23. VIEW LOOKING UPSTREAM AND TOWARD LEFT ABUTMENT OF DAM. NOTE FORMS FOR LEFT GRAVITY ABUTMENT AT UPPER RIGHT CORNER OF PICTURE. ARCHES 3, 4, 5, AND 7 COMPLETED TO ELEVATION 1795. 5 OR 7.5 FEET BELOW TOP OF PARAPET WALL. November 29, 1938 - Bartlett Dam, Verde River, Phoenix, Maricopa County, AZ

  14. 25. UPSTREAM VIEW OF LOWER END OF OUTLET STRUCTURE SHOWING ...

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

    25. UPSTREAM VIEW OF LOWER END OF OUTLET STRUCTURE SHOWING FORMS IN PLACE FOR GRAVITY WALL SECTIONS.... Volume XVI, No. 16, August 16, 1939. - Prado Dam, Outlet Works, Santa Ana River near junction of State Highways 71 & 91, Corona, Riverside County, CA

  15. PHOTO OF THE BOAT HOUSE, GATE HOUSE, UPSTREAM SIDE OF ...

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

    PHOTO OF THE BOAT HOUSE, GATE HOUSE, UPSTREAM SIDE OF SPILLWAYS LOOKING EAST; WATER INTAKE AND LOG BOOMS ARE SEEN ON RESERVOIR. PHOTO BY JET LOWE, HAER, 1995. - Elwha River Hydroelectric System, Glines Hydroelectric Dam & Plant, Port Angeles, Clallam County, WA

  16. 3. FORMER INTAKE DAM NO. 2, VIEW LOOKING UPSTREAM AT ...

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

    3. FORMER INTAKE DAM NO. 2, VIEW LOOKING UPSTREAM AT LEFT IS RUBBLE MASONRY COVERING INTERSECTION OF THE TWO IRON PIPES FROM NEW DAM ENTERING OLD INTAKE OPENING AT RIGHT IS BOX FLUME LEADING TO AERATOR. - Kalaupapa Water Supply System, Waikolu Valley to Kalaupapa Settlement, Island of Molokai, Kalaupapa, Kalawao County, HI

  17. 1. OVERALL VIEW OF WHITE MILLER LAKE AND UPSTREAM FACE ...

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

    1. OVERALL VIEW OF WHITE MILLER LAKE AND UPSTREAM FACE OF DAM, LOOKING NORTH - High Mountain Dams in Upalco Unit, White Miller Lake Dam, Ashley National Forest, 6.9 miles North of Swift Creek Campground, Mountain Home, Duchesne County, UT

  18. 8. GENERAL EXTERIOR VIEW LOOKING NORTHWEST TOWARD UPSTREAM END OF ...

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

    8. GENERAL EXTERIOR VIEW LOOKING NORTHWEST TOWARD UPSTREAM END OF NAVIGATION LOCK #1; SOUTH END OF POWERHOUSE #1 IS VISIBLE ON RIGHT; BRADFORD SLOUGH IS VISIBLE IN FOREGROUND. - Bonneville Project, Navigation Lock No. 1, Oregon shore of Columbia River near first Powerhouse, Bonneville, Multnomah County, OR

  19. View of upstream face of the forebay dam of Grand ...

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

    View of upstream face of the forebay dam of Grand Coulee Dam, looking southwest. Note the trash racks at the entrance to the penstocks. - Columbia Basin Project, Grand Coulee Dam & Franklin D. Roosevelt Lake, Across Columbia River, Southeast of Town of Grand Coulee, Grand Coulee, Grant County, WA

  20. 6. AERATOR VIEWED UPSTREAM. DETAIL OF FLUSH VALVE AND VIEW ...

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

    6. AERATOR VIEWED UPSTREAM. DETAIL OF FLUSH VALVE AND VIEW INTO BOX FLUME. NOTE WRENCH TO OPEN VALVE AND REMAINS OF OLD SHOVEL USED FOR MAINTENANCE. TRASH SCREEN MESH IS SEEN AT BOTTOM LEFT. - Kalaupapa Water Supply System, Waikolu Valley to Kalaupapa Settlement, Island of Molokai, Kalaupapa, Kalawao County, HI

  1. 1. VIEW NORTH FROM UPSTREAM WITH IMPOUNDED LAKE AND (LEFT ...

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

    1. VIEW NORTH FROM UPSTREAM WITH IMPOUNDED LAKE AND (LEFT TO RIGHT): EARTHEN DIKE, HYDROELECTRIC GENERATING FACILITY, AND DAM - Middle Creek Hydroelectric Dam, On Middle Creek, West of U.S. Route 15, 3 miles South of Selinsgrove, Selinsgrove, Snyder County, PA

  2. 2. CONTEXTUAL VIEW FROM UPSTREAM OF BRIDGE IN ITS SETTING, ...

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

    2. CONTEXTUAL VIEW FROM UPSTREAM OF BRIDGE IN ITS SETTING, LOOKING SOUTH-SOUTHWEST FROM LOWER (RAILROAD) DECK OF SOUTHERN PACIFIC TRANSPORTATION COMPANY'S I STREET BRIDGE - Sacramento River Bridge, Spanning Sacramento River at California State Highway 275, Sacramento, Sacramento County, CA

  3. 10. VIEW UPSTREAM OF PIPELINE SECTION AT JUNCTION OF HUME ...

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

    10. VIEW UPSTREAM OF PIPELINE SECTION AT JUNCTION OF HUME CEMENT PIPE AND CAST-IRON (460'). NOTE CYLINDRICAL COLLAR OF CEMENT SECTIONS AND BELL JUNCTIONS OF IRON PIPE. - Kalaupapa Water Supply System, Waikolu Valley to Kalaupapa Settlement, Island of Molokai, Kalaupapa, Kalawao County, HI

  4. 10. View to west from Jacob Meyer Park, showing upstream ...

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

    10. View to west from Jacob Meyer Park, showing upstream (east) side of truss span. Bend is visible in lower portion of damaged vertical compression member third from right. - Stanislaus River Bridge, Atchison, Topeka & Santa Fe Railway at Stanislaus River, Riverbank, Stanislaus County, CA

  5. 32. AERIAL VIEW OF TIETON DAM, UPSTREAM FACE OF DAM ...

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

    32. AERIAL VIEW OF TIETON DAM, UPSTREAM FACE OF DAM (Trashrack-structure for outlet at lower left in reservoir, spillway at upper left. Reservoir nearly empty due to drought.) - Tieton Dam, South & East of State Highway 12, Naches, Yakima County, WA

  6. 43. View of log boom (upstream) protecting fish screens at ...

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

    43. View of log boom (upstream) protecting fish screens at Dingle Basin, looking southwest from north side of basin. Photo by Brian C. Morris, PUget Power, 1989. - Puget Sound Power & Light Company, White River Hydroelectric Project, 600 North River Avenue, Dieringer, Pierce County, WA

  7. 45. View of upstream face of fish screens at Dingle ...

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

    45. View of upstream face of fish screens at Dingle Basin, looking northwest from south side of basin. Photo by Brian C. Morris, Puget Power, 1989. - Puget Sound Power & Light Company, White River Hydroelectric Project, 600 North River Avenue, Dieringer, Pierce County, WA

  8. 2. VIEW OF UPSTREAM SIDE OF HISTORIC OUTLET WORKS TAKEN ...

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

    2. VIEW OF UPSTREAM SIDE OF HISTORIC OUTLET WORKS TAKEN FROM CENTER OF THE CHANNEL FROM TWIN LAKES. VIEW LOOKING EAST. - Twin Lakes Dam & Outlet Works, Beneath Twin Lakes Reservoir, T11S, R80W, S22, Twin Lakes, Lake County, CO

  9. View of Stehr Lake from FS 502 looking upstream (northeast). ...

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

    View of Stehr Lake from FS 502 looking upstream (northeast). Vehicle at right center is parked on earthen Upper Stehr Lake Dam. - Childs-Irving Hydroelectric Project, Childs System, Stehr Lake & Dams, Forest Service Road 708/502, Camp Verde, Yavapai County, AZ

  10. 13. Detail, upper chord connection point on upstream side of ...

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

    13. Detail, upper chord connection point on upstream side of truss, showing connection of upper chord, laced vertical compression member, knee-braced strut, counters, and laterals. - Red Bank Creek Bridge, Spanning Red Bank Creek at Rawson Road, Red Bluff, Tehama County, CA

  11. 42. VIEW OF STAGE RECORDER AT END OF UPSTREAM GUIDE ...

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

    42. VIEW OF STAGE RECORDER AT END OF UPSTREAM GUIDE WALL, LOOKING NORTHEAST. (Several hours after this view was taken, the stage recorder was hit a~d heavily damaged by a grain barge.) - Upper Mississippi River 9-Foot Channel, Lock & Dam No. 9, Lynxville, Crawford County, WI

  12. 12. Upstream view showing thelower log pond log chute in ...

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

    12. Upstream view showing thelower log pond log chute in the main channel of the Hudson River. The log chute in the dam can be seen in the background. Facing southwest. - Glens Falls Dam, 100' to 450' West of U.S. Route 9 Bridge Spanning Hudson River, Glens Falls, Warren County, NY

  13. 18. View to southwest. Detail, bearing shoe, upstream side of ...

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

    18. View to southwest. Detail, bearing shoe, upstream side of east pier. Copy negative made from 35mm color transparency made with with 135mm lens by John Snyder, due to lack of sufficiently long lens for 4x5 camera. - South Fork Trinity River Bridge, State Highway 299 spanning South Fork Trinity River, Salyer, Trinity County, CA

  14. DESCHUTES PROJECT – WICKIUP DAM – VIEW OF UPSTREAM FACE ...

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

    DESCHUTES PROJECT – WICKIUP DAM – VIEW OF UPSTREAM FACE FROM RIGHT ABUTMENT. CPS CREW PLACING RIPRAP. Photocopy of historic photographs (original photograph on file at National Archives, Rocky Mountain Region, Denver, CO). Unknown USBR Photographer, July 26, 1944 - Wickiup Dam, Deschutes River, La Pine, Deschutes County, OR

  15. VIEW OF UPSTREAM SIDE OF TUMALO RESERVOIR FEED CANAL INTAKE ...

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

    VIEW OF UPSTREAM SIDE OF TUMALO RESERVOIR FEED CANAL INTAKE STRUCTURE, OLD COLUMBIA SOUTHERN CANAL POND OUTLET (FAR LEFT), AND NEW COLUMBIA SOUTHERN CANAL INTAKE STRUCTURES (FAR RIGHT). LOOKING NORTH - Tumalo Irrigation District, Tumalo Project, West of Deschutes River, Tumalo, Deschutes County, OR

  16. DESCHUTES. WICKIUP DAM OUTLET WORKS. GENERAL VIEW LOOKING UPSTREAM FROM ...

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

    DESCHUTES. WICKIUP DAM OUTLET WORKS. GENERAL VIEW LOOKING UPSTREAM FROM LEFT BANK OF DESCHUTES RIVER. Photocopy of historic photograph (original photograph on file at National Archives, Rocky Mountain Region, Denver, CO). Unknown USBR photographer, August 5, 1940 - Wickiup Dam, Outlet Works, Deschutes River, La Pine, Deschutes County, OR

  17. DESCHUTES PROJECT – WICKIUP DAM – RIPRAP ON UPSTREAM FACE ...

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

    DESCHUTES PROJECT – WICKIUP DAM – RIPRAP ON UPSTREAM FACE OF DAM. Photocopy of historic photographs (original photograph on file at National Archives, Rocky Mountain Region, Denver, CO). Unknown USBR Photographer, October 1, 1942 - Wickiup Dam, Deschutes River, La Pine, Deschutes County, OR

  18. DESCHUTES. WICKIUP DAM OUTLET WORKS. GENERAL VIEW LOOKING UPSTREAM FROM ...

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

    DESCHUTES. WICKIUP DAM OUTLET WORKS. GENERAL VIEW LOOKING UPSTREAM FROM LEFT BANK OF DESCHUTES RIVER. MONTAG & SONS, CONTRACTOR. Photocopy of historic photograph (original photograph on file at National Archives, Rocky Mountain Region, Denver, CO). Unknown USBR photographer, November 24, 1940 - Wickiup Dam, Outlet Works, Deschutes River, La Pine, Deschutes County, OR

  19. DESCHUTES PROJECT, WICKIUP RESERVOIR, UPSTREAM SIDE OF COMPLETED EAST DIKE ...

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

    DESCHUTES PROJECT, WICKIUP RESERVOIR, UPSTREAM SIDE OF COMPLETED EAST DIKE FROM RIGHT ABUTMENT. Photocopy of historic photograph (original photograph on file at National Archives, Rocky Mountain Region, Denver, CO). R.A. Baker, photographer, August 29, 1947 - Wickiup Dam, Dikes and Spillway, Deschutes River, La Pine, Deschutes County, OR

  20. DESCHUTES PROJECT – VIEW OF RIPRAP ON UPSTREAM FACE OF ...

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

    DESCHUTES PROJECT – VIEW OF RIPRAP ON UPSTREAM FACE OF WICKIUP DAM FROM RIGHT BANK. Photocopy of historic photographs (original photograph on file at National Archives, Rocky Mountain Region, Denver, CO). Unknown USBR Photographer, August 31, 1943 - Wickiup Dam, Deschutes River, La Pine, Deschutes County, OR

  1. DESCHUTES, WICKIUP DAM OUTLET WORKS. STILLING BASIN LOOKING UPSTREAM. MONTAG ...

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

    DESCHUTES, WICKIUP DAM OUTLET WORKS. STILLING BASIN LOOKING UPSTREAM. MONTAG & SONS, CONTRACTOR. Photocopy of historic photograph (original photograph on file at National Archives, Rocky Mountain Region, Denver, CO). Unknown USBR photographer, April 18, 1940 - Wickiup Dam, Outlet Works, Deschutes River, La Pine, Deschutes County, OR

  2. DESCHUTES. WICKIUP DAM OUTLET WORKS. LOOKING UPSTREAM FROM VALVE HOUSE ...

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

    DESCHUTES. WICKIUP DAM OUTLET WORKS. LOOKING UPSTREAM FROM VALVE HOUSE TOWARD GATE CHAMBER. Photocopy of historic photograph (original photograph on file at National Archives, Rocky Mountain Region, Denver, CO). Unknown USBR photographer, October 22, 1940 - Wickiup Dam, Outlet Works, Deschutes River, La Pine, Deschutes County, OR

  3. DESCHUTES. WICKIUP DAM OUTLET WORKS, LOOKING UPSTREAM. REINFORCING STEEL IN ...

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

    DESCHUTES. WICKIUP DAM OUTLET WORKS, LOOKING UPSTREAM. REINFORCING STEEL IN PLACE FOR FLOOR OF STILLING BASIN IN FOREGROUND. Photocopy of historic photograph (original photograph on file at National Archives, Rocky Mountain Region, Denver, CO). Unknown USBR photographer, June 17, 1940 - Wickiup Dam, Outlet Works, Deschutes River, La Pine, Deschutes County, OR

  4. DESCHUTES. WICKIUP DAM OUTLET WORKS. LOOKING UPSTREAM, THROUGH STILL BASIN, ...

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

    DESCHUTES. WICKIUP DAM OUTLET WORKS. LOOKING UPSTREAM, THROUGH STILL BASIN, MONTAG & SONS, CONTRACTOR, POURING CONCRETE IN CENTER WALL. Photocopy of historic photograph (original photograph on file at National Archives, Rocky Mountain Region, Denver, CO). Unknown USBR photographer, August 24, 1940 - Wickiup Dam, Outlet Works, Deschutes River, La Pine, Deschutes County, OR

  5. View of upstream face of Grand Coulee Dam, looking northeast. ...

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

    View of upstream face of Grand Coulee Dam, looking northeast. This image features a partially cloudy sky.) - Columbia Basin Project, Grand Coulee Dam & Franklin D. Roosevelt Lake, Across Columbia River, Southeast of Town of Grand Coulee, Grand Coulee, Grant County, WA

  6. View of upstream face of the forebay dam of Grand ...

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

    View of upstream face of the forebay dam of Grand Coulee Dam, looking west. Construction of the forebay dam, which replaced the eastern end of the original Grand Coulee Dam, was completed in 1974. - Columbia Basin Project, Grand Coulee Dam & Franklin D. Roosevelt Lake, Across Columbia River, Southeast of Town of Grand Coulee, Grand Coulee, Grant County, WA

  7. 4. AERATOR AT 525, CONSTRUCTED 19371938, VIEW FROM UPSTREAM (TRASH ...

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

    4. AERATOR AT 525, CONSTRUCTED 1937-1938, VIEW FROM UPSTREAM (TRASH SCREEN REMOVED FOR CLARITY), WATER FROM INTAKE FLOWS THROUGH FLUME, THEN DAMS, AND SPILLS OVER STEPS TO MIX WITH OXYGEN, THUS REDUCING ACIDITY LEVELS. ACID INDUCES FASTER CORROSION OF PIPES AND SPOILS TASTE. - Kalaupapa Water Supply System, Waikolu Valley to Kalaupapa Settlement, Island of Molokai, Kalaupapa, Kalawao County, HI

  8. VIEW OF UPSTREAM (EAST) SIDES OF UPPER (EAST) END OF ...

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

    VIEW OF UPSTREAM (EAST) SIDES OF UPPER (EAST) END OF LOCK, SOUTHEAST AND NORTHEAST CONTROL HOUSES, LOCK UNDER REPAIR, BUILDING NOS. 51, 52 AND SOUTHWEST CONTROL HOUSE IN BACKGROUND, VIEW TOWARDS WEST-NORTHWEST - Ortona Lock, Lock No. 2, Machinery and Control Houses, Caloosahatchee River, Cross-State Canal, Okeechobee Intracoastal Waterway, Ortona, Glades County, FL

  9. Multispacecraft observations of diffuse ions upstream of Earth's bow shock

    NASA Astrophysics Data System (ADS)

    Kis, A.; Scholer, M.; Klecker, B.; Moebius, E.; Lucek, E.; Reme, H.

    We present observations of upstream ions at times of large separation distance between the Cluster spacecraft (~5000 km). On 18 February, 2003, during particulary quiet interplanetary conditions, the Cluster spacecraft were moving inbound through the foreshock region, where for more than 12 hours they simultaneously observed a continuous presence of a diffuse ion population. Using the HIA and CODIF sensors of the CIS plasma instrument onboard SC-1 and -3, we were able to directly measure the upstream ion density gradients in the energy range 10-32 keV in several energy bands. During this time period, the spacecraft distance from the bow shock parallel to the local magnetic field varies considerably (between 0 and 15 Re). The distance to the bow shock has been determined by using upstream magnetic field and plasma parameters and a bow shock model. We find up to 10 Re from the bow shock an exponential decrease of the upstream ion density, with an e-folding distance increasing from 3.1 to 5.6 Re at energies from 10 keV to 32 keV, respectively. From the e-folding distance the parallel diffusion coefficient and its energy dependence can be determined. At distances more than 10 Re the gradient is close to zero.

  10. 2. UPSTREAM SIDE OF DAM AND BRIDGE WITH ABANDONED SAN ...

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

    2. UPSTREAM SIDE OF DAM AND BRIDGE WITH ABANDONED SAN TAN FLOOD-WATER HEADGATE IN FOREGROUND. TAKEN FROM NORTH END OF DAM - San Carlos Irrigation Project, Sacaton Dam & Bridge, Gila River, T4S R6E S12/13, Coolidge, Pinal County, AZ

  11. 14. VIEW SHOWING UPSTREAM FACE OF HORSE MESA. TRACK FROM ...

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

    14. VIEW SHOWING UPSTREAM FACE OF HORSE MESA. TRACK FROM AGGREGATE BARGES TO MIXING PLANT IS AT LOWER LEFT, RIGHT SPILLWAY CHUTE IS TAKING FORM AT UPPER RIGHT April 29, 1927 - Horse Mesa Dam, Salt River, 65 miles East of Phoenix, Phoenix, Maricopa County, AZ

  12. 6. UPSTREAM VIEW OF THE SPILLWAY OF THE POST FALLS ...

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

    6. UPSTREAM VIEW OF THE SPILLWAY OF THE POST FALLS POWERHOUSE, WITH A PARTIAL VIEW OF THE MODERN TRANSFORMER IN THE FOREGROUND, AND THE OLD SWITCHING BUILDING IN THE LEFT BACKGROUND, LOOKING SOUTHEAST. - Washington Water Power Company Post Falls Power Plant, Middle Channel Powerhouse & Dam, West of intersection of Spokane & Fourth Streets, Post Falls, Kootenai County, ID

  13. 5. UPSTREAM VIEW OF THE TRASH RAKES, GATES AND GATELIFTING ...

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

    5. UPSTREAM VIEW OF THE TRASH RAKES, GATES AND GATE-LIFTING MECHANISMS FOR THE POST FALLS DAM AND POWERHOUSE, LOOKING NORTHWEST. - Washington Water Power Company Post Falls Power Plant, Middle Channel Powerhouse & Dam, West of intersection of Spokane & Fourth Streets, Post Falls, Kootenai County, ID

  14. 18. Upstream face of arches, concrete placing tower is at ...

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

    18. Upstream face of arches, concrete placing tower is at far right. Tower at center was used to convey material. Photographer unknown, January 29, 1927. Source: MWD. - Waddell Dam, On Agua Fria River, 35 miles northwest of Phoenix, Phoenix, Maricopa County, AZ

  15. 63. Upstream face of Waddell Dam as viewed from the ...

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

    63. Upstream face of Waddell Dam as viewed from the west abutment. Crane at center is used to service the penstock intake. Photographer Mark Durben. Source: Salt River Project. - Waddell Dam, On Agua Fria River, 35 miles northwest of Phoenix, Phoenix, Maricopa County, AZ

  16. 14. Close up view of upstream side of Taintor gates ...

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

    14. Close up view of upstream side of Taintor gates being installed. Placement tower chute is at upper right. Photographer unknown, January 6, 1925. Source: Salt River Project. - Mormon Flat Dam, On Salt River, Eastern Maricopa County, east of Phoenix, Phoenix, Maricopa County, AZ

  17. 1. View looking upstream (southwest) at diversion dam. Water enters ...

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

    1. View looking upstream (southwest) at diversion dam. Water enters half-round flume on right. Break in diversion structure provides a view of water flow in flume during the high water runoff in June. - Rock Creek Hydroelectric Project, Rock Creek, Baker County, OR

  18. 11. VIEW OF UPSTREAM ELEVATION OF BIG DALTON DAM SHOWING ...

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

    11. VIEW OF UPSTREAM ELEVATION OF BIG DALTON DAM SHOWING CONSTRUCTION OF THE ARCH WALLS, TAKEN ON SEPTEMBER 11, 1928 (PHOTOGRAPHER UNKNOWN). PICTURE WAS DEVELOPED FROM COPY NEGATIVES WHICH WERE TAKEN ON 6/5/1973 BY PHOTOGRAPHER GATSON OF L.A. COUNTY PUBLIC WORKS. - Big Dalton Dam, 2600 Big Dalton Canyon Road, Glendora, Los Angeles County, CA

  19. "Upstream"-The Case for Professional Counseling in Residence Halls.

    ERIC Educational Resources Information Center

    Rickgarn, Ralph L.

    1985-01-01

    Presents "upstream", a model for the utilization of professional counseling services in the residence halls, encompassing developmental, preventive, and remedial approaches. Suggests that the professional counselor can assist in four capacities in the actualization of these approaches: as a therapist, as a consultant, as a change agent, and as a…

  20. Advection of methane in the hydrate zone: model, analysis and examples

    NASA Astrophysics Data System (ADS)

    Peszynska, Malgorzata; Showalter, Ralph E.; Webster, Justin T.

    2015-12-01

    A two-phase two-component model is formulated for the advective-diffusive transport of methane in liquid phase through sediment with the accompanying formation and dissolution of methane hydrate. This free-boundary problem has a unique generalized solution in $L^1$; the proof combines analysis of the stationary semilinear elliptic Dirichlet problem with the nonlinear semigroup theory in Banach space for an m-accretive multi-valued operator. Additional estimates of maximum principle type are obtained, and these permit appropriate maximal extensions of the phase-change relations. An example with pure advection indicates the limitations of these estimates and of the model developed here. We also consider and analyze the coupled pressure equation that determines the advective flux in the transport model.

  1. Metamorphism during temperature gradient with undersaturated advective airflow in a snow sample

    NASA Astrophysics Data System (ADS)

    Ebner, Pirmin Philipp; Schneebeli, Martin; Steinfeld, Aldo

    2016-04-01

    Snow at or close to the surface commonly undergoes temperature gradient metamorphism under advective flow, which alters its microstructure and physical properties. Time-lapse X-ray microtomography is applied to investigate the structural dynamics of temperature gradient snow metamorphism exposed to an advective airflow in controlled laboratory conditions. Cold saturated air at the inlet was blown into the snow samples and warmed up while flowing across the sample with a temperature gradient of around 50 K m-1. Changes of the porous ice structure were observed at mid-height of the snow sample. Sublimation occurred due to the slight undersaturation of the incoming air into the warmer ice matrix. Diffusion of water vapor opposite to the direction of the temperature gradient counteracted the mass transport of advection. Therefore, the total net ice change was negligible leading to a constant porosity profile. However, the strong recrystallization of water molecules in snow may impact its isotopic or chemical content.

  2. First-Order Hyperbolic System Method for Time-Dependent Advection-Diffusion Problems

    NASA Technical Reports Server (NTRS)

    Mazaheri, Alireza; Nishikawa, Hiroaki

    2014-01-01

    A time-dependent extension of the first-order hyperbolic system method for advection-diffusion problems is introduced. Diffusive/viscous terms are written and discretized as a hyperbolic system, which recovers the original equation in the steady state. The resulting scheme offers advantages over traditional schemes: a dramatic simplification in the discretization, high-order accuracy in the solution gradients, and orders-of-magnitude convergence acceleration. The hyperbolic advection-diffusion system is discretized by the second-order upwind residual-distribution scheme in a unified manner, and the system of implicit-residual-equations is solved by Newton's method over every physical time step. The numerical results are presented for linear and nonlinear advection-diffusion problems, demonstrating solutions and gradients produced to the same order of accuracy, with rapid convergence over each physical time step, typically less than five Newton iterations.

  3. Power law breakthrough curve tailing in a fracture: The role of advection

    NASA Astrophysics Data System (ADS)

    Fiori, Aldo; Becker, Matthew W.

    2015-06-01

    We offer an explanation of the strongly tailed solute breakthrough curve typically observed when a tracer test is conducted in fractured bedrock. In this example, we limit the model to a single planar fracture of varying aperture. Flow heterogeneity derives from variable fracture aperture, which implies variable transmissivity (T). The analysis employs a physically based model well-suited to strong heterogeneity and relies only upon advective transport. The purely advective model is able to explain a power-law trend of magnitude -2 to -3 in the breakthrough curve tail; a range that has been found in field tracer experiments. The principle cause of this trend is the comparatively slow transport in zones of small transmissivity (tight aperture). Slow advection occurs when either heterogeneity (variance of lnT) is strong or when the assumed heterogeneity distribution is non-Gaussian. Thus, we link breakthrough tailing to the statistical parameters for the transmissivity field.

  4. Warm-air advection, air mass transformation and fog causes rapid ice melt

    NASA Astrophysics Data System (ADS)

    Tjernström, Michael; Shupe, Matthew D.; Brooks, Ian M.; Persson, P. Ola G.; Prytherch, John; Salisbury, Dominic J.; Sedlar, Joseph; Achtert, Peggy; Brooks, Barbara J.; Johnston, Paul E.; Sotiropoulou, Georgia; Wolfe, Dan

    2015-07-01

    Direct observations during intense warm-air advection over the East Siberian Sea reveal a period of rapid sea-ice melt. A semistationary, high-pressure system north of the Bering Strait forced northward advection of warm, moist air from the continent. Air-mass transformation over melting sea ice formed a strong, surface-based temperature inversion in which dense fog formed. This induced a positive net longwave radiation at the surface while reducing net solar radiation only marginally; the inversion also resulted in downward turbulent heat flux. The sum of these processes enhanced the surface energy flux by an average of ~15 W m-2 for a week. Satellite images before and after the episode show sea-ice concentrations decreasing from > 90% to ~50% over a large area affected by the air-mass transformation. We argue that this rapid melt was triggered by the increased heat flux from the atmosphere due to the warm-air advection.

  5. Altimetric lagrangian advection to reconstruct Pacific Ocean fine scale surface tracer fields

    NASA Astrophysics Data System (ADS)

    Rogé, Marine; Morrow, Rosemary; Dencausse, Guillaume

    2015-04-01

    In past studies, lagrangian stirring of surface tracer fields by altimetric surface geostrophic currents has been performed in different mid to high-latitude regions, showing good results in reconstructing finer-scale tracer patterns. Here we apply the technique to three different regions in the eastern and western tropical Pacific, and in the subtropical southwest Pacific. Initial conditions are derived from weekly gridded temperature and salinity fields, based on hydrographic data and Argo. Validation of the improved fine-scale surface tracer fields is performed using satellite AMSRE SST data, and high-resolution ship thermosalinograph data. We test two kinds of lagrangian advection. The standard one-way advection is shown to introduce an increased tracer bias as the advection time increases. Indeed, since we only use passive stirring, a bias is introduced from the missing physics, such as air-sea fluxes or mixing. A second "backward-forward" advection technique is shown to reduce the seasonal bias, but more data is lost around coasts and islands, a strong handicap in the tropical Pacific with many small islands. In the subtropical Pacific Ocean, the mesoscale temperature and salinity fronts are well represented by the one-way advection over a 10-day advection time, including westward propagating features not apparent in the initial fields. In the tropics, the results are less clear. The validation is hampered by the complex vertical stratification, and the technique is limited by the lack of accurate surface currents for the stirring - the gridded altimetric fields poorly represent the meridional currents, and are not detecting the fast tropical instability waves, nor the wind-driven circulation. We suggest that the passive lateral stirring technique is efficient in regions with moderate the high mesoscale energy and correlated mesoscale surface temperature and surface height. In other regions, more complex dynamical processes may need to be included.

  6. Altimetric Lagrangian advection to reconstruct Pacific Ocean fine-scale surface tracer fields

    NASA Astrophysics Data System (ADS)

    Rogé, Marine; Morrow, Rosemary A.; Dencausse, Guillaume

    2015-09-01

    In past studies, Lagrangian stirring of surface tracer fields by altimetric surface geostrophic currents has been performed in different mid- to high-latitude regions, showing good results in reconstructing finer scale tracer patterns. Here, we explore the pertinence of the technique in the western equatorial Pacific and in the subtropical southwest Pacific. Initial conditions are derived from weekly gridded low-resolution temperature and salinity fields based on in situ hydrographic data. Validation of the reconstructed fine-scale surface tracer fields is performed using satellite AMSRE Sea Surface Temperature data and high-resolution ship thermosalinograph data. We test two kinds of Lagrangian advection. The standard one-way advection leads to an increased error as the advection time increases, due to the missing physics, such as air-sea fluxes or non-geostrophic dynamics. A second "backward-forward" advection technique is explored to reduce this bias in the tracer field, with improved results. In the subtropical southwest Pacific Ocean, the mesoscale temperature and salinity fronts are well represented by both Lagrangian advection techniques over a short 7- to 14-day advection time, including westward-propagating features not apparent in the initial fields. In the tropics, the results are less clear. The validation is hampered by the complex vertical stratification, and the lateral stirring technique is limited by the pertinence of using geostrophic surface current fields in the tropics. We suggest that the passive lateral stirring technique is efficient in regions with moderate to high mesoscale energy, where mesoscale surface tracer and surface height fields are correlated. In other regions, more complex dynamical processes may need to be included.

  7. Detecting floodplain inundation based on the upstream-downstream relationship

    NASA Astrophysics Data System (ADS)

    Zhao, Tongtiegang; Shao, Quanxi

    2015-11-01

    The rise in river stage (water depth) can lead to disastrous floodplain inundation. On the basis of hydraulic simulation data, this study proposes novel data-analytical methods to infer the threshold river stage and detect floodplain inundation. A quasi-Muskingum model is derived from the classical Muskingum model to characterise the relationship between upstream and downstream river stages. Based on this model, F-test and modified Akaike information criterion AICc are introduced to test if there is a change of the upstream-downstream relationship. Furthermore, a bootstrap-based calibration-validation experiment is set up to evaluate the performance of the quasi-Muskingum model. The proposed methods are applied to a case study of the 1991 and 2001 floods in the Flinders and Norman Rivers in Northern Australia. The results show that floodplain inundation does change the upstream-downstream relationship as it drastically alters the stage-discharge relationship. To combine the quasi-Muskingum model with F-test and AICc facilitates an efficient approach to detect the change and infer the threshold river stage. The analytical testing is in concert with visual examination - the time when the river stage becomes higher than the detected threshold coincides with the beginning of floodplain inundation. Despite the change, the quasi-Muskingum model effectively captures the upstream-downstream relationship and requires a small number of samples in calibration. This study highlights the effectiveness of the data-analytical methods in dealing with the change of the upstream-downstream relationship.

  8. Geometrical splitting technique to improve the computational efficiency in Monte Carlo calculations for proton therapy

    SciTech Connect

    Ramos-Mendez, Jose; Perl, Joseph; Faddegon, Bruce; Schuemann, Jan; Paganetti, Harald

    2013-04-15

    Purpose: To present the implementation and validation of a geometrical based variance reduction technique for the calculation of phase space data for proton therapy dose calculation. Methods: The treatment heads at the Francis H Burr Proton Therapy Center were modeled with a new Monte Carlo tool (TOPAS based on Geant4). For variance reduction purposes, two particle-splitting planes were implemented. First, the particles were split upstream of the second scatterer or at the second ionization chamber. Then, particles reaching another plane immediately upstream of the field specific aperture were split again. In each case, particles were split by a factor of 8. At the second ionization chamber and at the latter plane, the cylindrical symmetry of the proton beam was exploited to position the split particles at randomly spaced locations rotated around the beam axis. Phase space data in IAEA format were recorded at the treatment head exit and the computational efficiency was calculated. Depth-dose curves and beam profiles were analyzed. Dose distributions were compared for a voxelized water phantom for different treatment fields for both the reference and optimized simulations. In addition, dose in two patients was simulated with and without particle splitting to compare the efficiency and accuracy of the technique. Results: A normalized computational efficiency gain of a factor of 10-20.3 was reached for phase space calculations for the different treatment head options simulated. Depth-dose curves and beam profiles were in reasonable agreement with the simulation done without splitting: within 1% for depth-dose with an average difference of (0.2 {+-} 0.4)%, 1 standard deviation, and a 0.3% statistical uncertainty of the simulations in the high dose region; 1.6% for planar fluence with an average difference of (0.4 {+-} 0.5)% and a statistical uncertainty of 0.3% in the high fluence region. The percentage differences between dose distributions in water for simulations

  9. Geometrical splitting technique to improve the computational efficiency in Monte Carlo calculations for proton therapy

    PubMed Central

    Ramos-Méndez, José; Perl, Joseph; Faddegon, Bruce; Schümann, Jan; Paganetti, Harald

    2013-01-01

    Purpose: To present the implementation and validation of a geometrical based variance reduction technique for the calculation of phase space data for proton therapy dose calculation. Methods: The treatment heads at the Francis H Burr Proton Therapy Center were modeled with a new Monte Carlo tool (TOPAS based on Geant4). For variance reduction purposes, two particle-splitting planes were implemented. First, the particles were split upstream of the second scatterer or at the second ionization chamber. Then, particles reaching another plane immediately upstream of the field specific aperture were split again. In each case, particles were split by a factor of 8. At the second ionization chamber and at the latter plane, the cylindrical symmetry of the proton beam was exploited to position the split particles at randomly spaced locations rotated around the beam axis. Phase space data in IAEA format were recorded at the treatment head exit and the computational efficiency was calculated. Depth–dose curves and beam profiles were analyzed. Dose distributions were compared for a voxelized water phantom for different treatment fields for both the reference and optimized simulations. In addition, dose in two patients was simulated with and without particle splitting to compare the efficiency and accuracy of the technique. Results: A normalized computational efficiency gain of a factor of 10–20.3 was reached for phase space calculations for the different treatment head options simulated. Depth–dose curves and beam profiles were in reasonable agreement with the simulation done without splitting: within 1% for depth–dose with an average difference of (0.2 ± 0.4)%, 1 standard deviation, and a 0.3% statistical uncertainty of the simulations in the high dose region; 1.6% for planar fluence with an average difference of (0.4 ± 0.5)% and a statistical uncertainty of 0.3% in the high fluence region. The percentage differences between dose distributions in water for

  10. Rectangular split-ring resonators with single-split and two-splits under different excitations at microwave frequencies

    NASA Astrophysics Data System (ADS)

    Zahertar, S.; Yalcinkaya, A. D.; Torun, H.

    2015-11-01

    In this work, transmission characteristics of rectangular split-ring resonators with single-split and two-splits are analyzed at microwave frequencies. The resonators are coupled with monopole antennas for excitation. The scattering parameters of the devices are investigated under different polarizations of E and H fields. The magnetic resonances induced by E and H fields are identified and the differences in the behavior of the resonators due to orientations of the fields are explained based on simulation and experimental results. The addition of the second split of the device is investigated considering different configurations of the excitation vectors. It is demonstrated that the single-split and the two-splits resonators exhibit identical transmission characteristics for a certain excitation configuration as verified with simulations and experiments. The presented resonators can effectively function as frequency selective media for varying excitation conditions.

  11. Large-eddy Advection in Evapotranspiration Estimates from an Array of Eddy Covariance Towers

    NASA Astrophysics Data System (ADS)

    Lin, X.; Evett, S. R.; Gowda, P. H.; Colaizzi, P. D.; Aiken, R.

    2014-12-01

    Evapotranspiration was continuously measured by an array of eddy covariance systems and large weighting lysimeter in a sorghum in Bushland, Texas in 2014. The advective divergence from both horizontal and vertical directions were measured through profile measurements above canopy. All storage terms were integrated from the depth of soil heat flux plate to the height of eddy covariance measurement. Therefore, a comparison between the eddy covariance system and large weighing lysimeter was conducted on hourly and daily basis. The results for the discrepancy between eddy covariance towers and the lysimeter will be discussed in terms of advection and storage contributions in time domain and frequency domain.

  12. Split-mode ultrasonic transducer.

    PubMed

    Ostrovskii, Igor; Cremaldi, Lucien

    2013-08-01

    A split-mode ultrasonic transducer is investigated in both theory and experiment. This transducer is a two-dimensional structure of periodically poled domains in a ferroelectric wafer with free surfaces. The acoustic vibrations are excited by a radio frequency electric current applied along the length of the wafer, which allows the basal-plane surfaces to be free of metal coatings and thus ready for further biomedical applications. A specific physical property of this transducer consists of the multiple acousto-electric resonances, which occur due to an acoustic mode split when the acoustic half-wavelength is equal to the domain length. Possible applications include ultrasonic generation and detection at the micro-scale, intravascular sonification and visualization, ultrasound therapy of localized small areas such as the eye, biomedical applications for cell cultures, and traditional nondestructive testing including bones and tissues. A potential use of a non-metallized wafer is a therapeutic application with double action that is both ultrasound itself and an electric field over the wafer. The experimental measurements and theoretical calculations are in good agreement. PMID:23927212

  13. Algebraic techniques for diagonalization of a split quaternion matrix in split quaternionic mechanics

    SciTech Connect

    Jiang, Tongsong; Jiang, Ziwu; Zhang, Zhaozhong

    2015-08-15

    In the study of the relation between complexified classical and non-Hermitian quantum mechanics, physicists found that there are links to quaternionic and split quaternionic mechanics, and this leads to the possibility of employing algebraic techniques of split quaternions to tackle some problems in complexified classical and quantum mechanics. This paper, by means of real representation of a split quaternion matrix, studies the problem of diagonalization of a split quaternion matrix and gives algebraic techniques for diagonalization of split quaternion matrices in split quaternionic mechanics.

  14. Algebraic techniques for diagonalization of a split quaternion matrix in split quaternionic mechanics

    NASA Astrophysics Data System (ADS)

    Jiang, Tongsong; Jiang, Ziwu; Zhang, Zhaozhong

    2015-08-01

    In the study of the relation between complexified classical and non-Hermitian quantum mechanics, physicists found that there are links to quaternionic and split quaternionic mechanics, and this leads to the possibility of employing algebraic techniques of split quaternions to tackle some problems in complexified classical and quantum mechanics. This paper, by means of real representation of a split quaternion matrix, studies the problem of diagonalization of a split quaternion matrix and gives algebraic techniques for diagonalization of split quaternion matrices in split quaternionic mechanics.

  15. Dephasing in coherently split quasicondensates

    SciTech Connect

    Stimming, H.-P.; Mauser, N. J.; Mazets, I. E.

    2011-02-15

    We numerically model the evolution of a pair of coherently split quasicondensates. A truly one-dimensional case is assumed, so that the loss of the (initially high) coherence between the two quasicondensates is due to dephasing only, but not due to the violation of integrability and subsequent thermalization (which are excluded from the present model). We confirm the subexponential time evolution of the coherence between two quasicondensates {proportional_to}exp[-(t/t{sub 0}){sup 2/3}], experimentally observed by Hofferberth et al. [Nature 449, 324 (2007)]. The characteristic time t{sub 0} is found to scale as the square of the ratio of the linear density of a quasicondensate to its temperature, and we analyze the full distribution function of the interference contrast and the decay of the phase correlation.

  16. Minimal Doubling and Point Splitting

    SciTech Connect

    Creutz, M.

    2010-06-14

    Minimally-doubled chiral fermions have the unusual property of a single local field creating two fermionic species. Spreading the field over hypercubes allows construction of combinations that isolate specific modes. Combining these fields into bilinears produces meson fields of specific quantum numbers. Minimally-doubled fermion actions present the possibility of fast simulations while maintaining one exact chiral symmetry. They do, however, introduce some peculiar aspects. An explicit breaking of hyper-cubic symmetry allows additional counter-terms to appear in the renormalization. While a single field creates two different species, spreading this field over nearby sites allows isolation of specific states and the construction of physical meson operators. Finally, lattice artifacts break isospin and give two of the three pseudoscalar mesons an additional contribution to their mass. Depending on the sign of this mass splitting, one can either have a traditional Goldstone pseudoscalar meson or a parity breaking Aoki-like phase.

  17. Dark matter from split seesaw

    NASA Astrophysics Data System (ADS)

    Kusenko, Alexander; Takahashi, Fuminobu; Yanagida, Tsutomu T.

    2010-09-01

    The seesaw mechanism in models with extra dimensions is shown to be generically consistent with a broad range of Majorana masses. The resulting democracy of scales implies that the seesaw mechanism can naturally explain the smallness of neutrino masses for an arbitrarily small right-handed neutrino mass. If the scales of the seesaw parameters are split, with two right-handed neutrinos at a high scale and one at a keV scale, one can explain the matter-antimatter asymmetry of the universe, as well as dark matter. The dark matter candidate, a sterile right-handed neutrino with mass of several keV, can account for the observed pulsar velocities and for the recent data from Chandra X-ray Observatory, which suggest the existence of a 5 keV sterile right-handed neutrino.

  18. Salt splitting with ceramic membranes

    SciTech Connect

    Kurath, D.

    1996-10-01

    The purpose of this task is to develop ceramic membrane technologies for salt splitting of radioactively contaminated sodium salt solutions. This technology has the potential to reduce the low-level waste (LLW) disposal volume, the pH and sodium hydroxide content for subsequent processing steps, the sodium content of interstitial liquid in high-level waste (HLW) sludges, and provide sodium hydroxide free of aluminum for recycle within processing plants at the DOE complex. Potential deployment sites include Hanford, Savannah River, and Idaho National Engineering Laboratory (INEL). The technical approach consists of electrochemical separation of sodium ions from the salt solution using sodium (Na) Super Ion Conductors (NaSICON). As the name implies, sodium ions are transported rapidly through these ceramic crystals even at room temperatures.

  19. Gauge mediated mini-split

    NASA Astrophysics Data System (ADS)

    Cohen, Timothy; Craig, Nathaniel; Knapen, Simon

    2016-03-01

    We propose a simple model of split supersymmetry from gauge mediation. This model features gauginos that are parametrically a loop factor lighter than scalars, accommodates a Higgs boson mass of 125 GeV, and incorporates a simple solution to the μ- b μ problem. The gaugino mass suppression can be understood as resulting from collective symmetry breaking. Imposing collider bounds on μ and requiring viable electroweak symmetry breaking implies small a-terms and small tan β — the stop mass ranges from 105 to 108 GeV. In contrast with models with anomaly + gravity mediation (which also predict a one-loop loop suppression for gaugino masses), our gauge mediated scenario predicts aligned squark masses and a gravitino LSP. Gluinos, electroweakinos and Higgsinos can be accessible at the LHC and/or future colliders for a wide region of the allowed parameter space.

  20. A global spectral element model for poisson equations and advective flow over a sphere

    NASA Astrophysics Data System (ADS)

    Mei, Huan; Wang, Faming; Zeng, Zhong; Qiu, Zhouhua; Yin, Linmao; Li, Liang

    2016-03-01

    A global spherical Fourier-Legendre spectral element method is proposed to solve Poisson equations and advective flow over a sphere. In the meridional direction, Legendre polynomials are used and the region is divided into several elements. In order to avoid coordinate singularities at the north and south poles in the meridional direction, Legendre-Gauss-Radau points are chosen at the elements involving the two poles. Fourier polynomials are applied in the zonal direction for its periodicity, with only one element. Then, the partial differential equations are solved on the longitude-latitude meshes without coordinate transformation between spherical and Cartesian coordinates. For verification of the proposed method, a few Poisson equations and advective flows are tested. Firstly, the method is found to be valid for test cases with smooth solution. The results of the Poisson equations demonstrate that the present method exhibits high accuracy and exponential convergence. Highprecision solutions are also obtained with near negligible numerical diffusion during the time evolution for advective flow with smooth shape. Secondly, the results of advective flow with non-smooth shape and deformational flow are also shown to be reasonable and effective. As a result, the present method is proved to be capable of solving flow through different types of elements, and thereby a desirable method with reliability and high accuracy for solving partial differential equations over a sphere.

  1. General solution of a fractional diffusion-advection equation for solar cosmic-ray transport

    NASA Astrophysics Data System (ADS)

    Rocca, M. C.; Plastino, A. R.; Plastino, A.; Ferri, G. L.; de Paoli, A.

    2016-04-01

    In this effort we exactly solve the fractional diffusion-advection equation for solar cosmic-ray transport and give its general solution in terms of hypergeometric distributions. Numerical analysis of this equation shows that its solutions resemble power-laws.

  2. Contributions of advective and diffusive oxygen transport through multilayer composite caps over mine waste.

    PubMed

    Kim, Hong; Benson, Craig H

    2004-07-01

    The relative contributions of four mechanisms of oxygen transport in multilayer composite (MLC) caps placed over oxygen-consuming mine waste were evaluated using numerical and analytical methods. MLC caps are defined here as caps consisting of earthen and geosynthetic (polymeric) components where a composite barrier layer consisting of a geomembrane (1-2 mm thick polymeric sheet) overlying a clay layer is the primary barrier to transport. The transport mechanisms that were considered are gas-phase advective transport, gas-phase diffusive transport, liquid-phase advective transport via infiltrating precipitation and liquid-phase diffusive transport. A numerical model was developed to simulate gas-phase advective-diffusive transport of oxygen through a multilayer cap containing seven layers. This model was also used to simulate oxygen diffusion in the liquid phase. An approximate analytical method was used to compute the advective flux of oxygen in the liquid phase. The numerical model was verified for limiting cases using an analytical solution. Comparisons were also made between model predictions and field data for earthen caps reported by others. Results of the analysis show that the dominant mechanism for oxygen transport through MLC caps is gas-phase diffusion. For the cases that were considered, the gas-phase diffusive flux typically comprises at least 99% of the total oxygen flux. Thus, designers of MLC caps should focus on design elements and features that will limit diffusion of gas-phase oxygen. PMID:15145567

  3. An objective method for computing advective surface velocities from sequential infrared satellite images

    NASA Astrophysics Data System (ADS)

    Emery, W. J.; Thomas, A. C.; Collins, M. J.; Crawford, W. R.; Mackas, D. L.

    1986-11-01

    Using cross correlations between sequential infrared satellite images, an objective technique is developed to compute advective sea surface velocities. Cross correlations are computed in 32 × 32 pixel search (second image) and 22 × 22 template (first image) windows from gradients of sea surface temperature computed from the satellite images. Velocity vectors, computed from sequential images of the British Columbia coastal ocean, generally appear coherent and consistent with the seasonal surface current in the region. During periods of strong wind forcing, as indicated by maps of sea level pressure, the image advective velocities are stronger and more coherent spatially and appear to cross surface temperature gradients; when winds are weaker, the advective velocities correspond better with the infrared temperature patterns, suggesting the increased contribution of the geostrophic current to the surface flow. Velocities determined from coincident, near-surface drogued (5-10 m) buoys, positioned every half hour by internal LORAN-C units in mid-June, show excellent agreement with the image advective velocities. In addition, conductivity, temperature, and depth (CTD) measurements (taken during the buoy tracking) confirm the homogeneity of the upper 10 m, and CTD-derived geostrophic currents are consistent with both buoy and sequential image displacement velocities.

  4. Satellite-advection based solar forecasting: lessons learned and progress towards probabalistic solar forecasting

    NASA Astrophysics Data System (ADS)

    Rogers, M. A.

    2015-12-01

    Using satellite observations from GOES-E and GOES-W platforms in concert with GFS-derived cloud-level winds and a standalone radiative transfer model, an advection-derived forecast for surface GHI over the continental United States, with intercomparison between forecasts for four zones over the CONUS and Central Pacific with SURFRAD results. Primary sources for error in advection-based forecasts, primarily driven by false- or mistimed ramp events are discussed, with identification of error sources quantified along with techniques used to improve advection-based forecasts to approximately 10% MAE for designated surface locations. Development of a blended steering wind product utilizing NWP output combined with satellite-derived winds from AMV techniques to improve 0-1 hour advection forecasts will be discussed. Additionally, the use of two years' of solar forecast observations in the development of a prototype probablistic forecast for ramp events will be shown, with the intent of increasing the use of satellite-derived forecasts for grid operators and optimizing integration of renewable resources into the power grid. Elements of the work were developed under the 'Public-Private-Academic Partnership to Advance Solar Power Forecasting' project spearheaded by the National Center for Atmospheric Research.

  5. Exact analytical solutions for contaminant transport in rivers 1. The equilibrium advection-dispersion equation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Analytical solutions of the advection-dispersion equation and related models are indispensable for predicting or analyzing contaminant transport processes in streams and rivers, as well as in other surface water bodies. Many useful analytical solutions originated in disciplines other than surface-w...

  6. DEVELOPMENT AND DEMONSTRATION OF A BIDIRECTIONAL ADVECTIVE FLUX METER FOR SEDIMENT-WATER INTERFACE

    EPA Science Inventory

    A bidirectional advective flux meter for measuring water transport across the sediment-water interface has been successfully developed and field tested. The flow sensor employs a heat-pulse technique combined with a flow collection funnel for the flow measurement. Because the dir...

  7. A Study of the Physical Processes of an Advection Fog Boundary Layer

    NASA Astrophysics Data System (ADS)

    Liu, Duan Yang; Yan, Wen Lian; Yang, Jun; Pu, Mei Juan; Niu, Sheng Jie; Li, Zi Hua

    2016-01-01

    A large quantity of advection fog appeared in the Yangtze River delta region between 1 and 2 December 2009. Here, we detail the fog formation and dissipation processes and the background weather conditions. The fog boundary layer and its formation and dissipation mechanisms have also been analyzed using field data recorded in a northern suburb of Nanjing. The results showed the following: (1) This advection fog was generated by interaction between advection of a north-east cold ground layer and a south-east warm upper layer. The double-inversion structure generated by this interaction between the cold and warm advections and steady south-east vapour transport was the main cause of this long-lasting fog. The double-inversion structure provided good thermal conditions for the thick fog, and the south-east vapour transport was not only conducive to maintaining the thickness of the fog but also sustained its long duration. (2) The fog-top altitude was over 600 m for most of the time, and the fog reduced visibility to less than 100 m for approximately 12 h. (3) The low-level jet near the lower inversion layer also played a role in maintaining the thick fog system by promoting heat, momentum and south-east vapour transport.

  8. MECHANISM OF OUTFLOWS IN ACCRETION SYSTEM: ADVECTIVE COOLING CANNOT BALANCE VISCOUS HEATING?

    SciTech Connect

    Gu, Wei-Min

    2015-01-20

    Based on the no-outflow assumption, we investigate steady-state, axisymmetric, optically thin accretion flows in spherical coordinates. By comparing the vertically integrated advective cooling rate with the viscous heating rate, we find that the former is generally less than 30% of the latter, which indicates that the advective cooling itself cannot balance the viscous heating. As a consequence, for radiatively inefficient flows with low accretion rates such as M-dot ≲10{sup −3} M-dot {sub Edd}, where M-dot {sub Edd} is the Eddington accretion rate, the viscous heating rate will be larger than the sum of the advective cooling rate and the radiative cooling one. Thus, no thermal equilibrium can be established under the no-outflow assumption. We therefore argue that in such cases outflows ought to occur and take away more than 70% of the thermal energy generated by viscous dissipation. Similarly, for optically thick flows with extremely large accretion rates such as M-dot ≳10 M-dot {sub Edd}, outflows should also occur owing to the limited advection and the low efficiency of radiative cooling. Our results may help to understand the mechanism of outflows found in observations and numerical simulations.

  9. ADVECTION, EDGE, AND OASIS EFFECTS ON SPATIAL MOISTURE AND FLUX FIELDS FROM LIDAR

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Relatively narrow forest stands such as the riparian Tamarisk bordering the Rio Grande are subject to dry air advection from the adjacent semi-desert environment. The transport of warm dry air into the canopy has a profound effect upon the spatial properties of the moisture field and associated lat...

  10. Wind Tunnel Measurement of Turbulent and Advective Scalar Fluxes: A Case Study on Intersection Ventilation

    PubMed Central

    Kukačka, Libor; Nosek, Štĕpán; Kellnerová, Radka; Jurčáková, Klára; Jaňour, Zbyněk

    2012-01-01

    The objective of this study is to determine processes of pollution ventilation in the X-shaped street intersection in an idealized symmetric urban area for the changing approach flow direction. A unique experimental setup for simultaneous wind tunnel measurement of the flow velocity and the tracer gas concentration in a high temporal resolution is assembled. Advective horizontal and vertical scalar fluxes are computed from averaged measured velocity and concentration data within the street intersection. Vertical advective and turbulent scalar fluxes are computed from synchronized velocity and concentration signals measured in the plane above the intersection. All the results are obtained for five approach flow directions. The influence of the approach flow on the advective and turbulent fluxes is determined. The contribution of the advective and turbulent flux to the ventilation is discussed. Wind direction with the best dispersive conditions in the area is found. The quadrant analysis is applied to the synchronized signals of velocity and concentration fluctuation to determine events with the dominant contribution to the momentum flux and turbulent scalar flux. PMID:22649290

  11. Alteration of chaotic advection in blood flow around partial blockage zone: Role of hematocrit concentration

    NASA Astrophysics Data System (ADS)

    Maiti, Soumyabrata; Chaudhury, Kaustav; DasGupta, Debabrata; Chakraborty, Suman

    2013-01-01

    Spatial distributions of particles carried by blood exhibit complex filamentary pattern under the combined effects of geometrical irregularities of the blood vessels and pulsating pumping by the heart. This signifies the existence of so called chaotic advection. In the present article, we argue that the understanding of such pathologically triggered chaotic advection is incomplete without giving due consideration to a major constituent of blood: abundant presence of red blood cells quantified by the hematocrit (HCT) concentration. We show that the hematocrit concentration in blood cells can alter the filamentary structures of the spatial distribution of advected particles in an intriguing manner. Our results reveal that there primarily are two major impacts of HCT concentrations towards dictating the chaotic dynamics of blood flow: changing the zone of influence of chaotic mixing and determining the enhancement of residence time of the advected particles away from the wall. This, in turn, may alter the extent of activation of platelets or other reactive biological entities, bearing immense consequence towards dictating the biophysical mechanisms behind possible life-threatening diseases originating in the circulatory system.

  12. Split Immunological Tolerance to Trophoblast

    PubMed Central

    de Mestre, Amanda; Noronha, Leela; Wagner, Bettina; Antczak, Douglas F.

    2010-01-01

    Split immunological tolerance refers to states in which an individual is capable of mounting certain types of immune responses to a particular antigenic challenge, but is tolerant of the same antigen in other compartments of the immune system. This concept is applicable to the immunological relationship between mother and fetus, and particularly relevant in equine pregnancy. In pregnant mares, antibody responses to paternal foreign Major Histocompatibility Complex class I antigens are robust, while anti-paternal cytotoxic T cell responses are diminished compared to those mounted by non-pregnant mares. Here we compared the distribution of the major lymphocyte subsets, the percentage of lymphocytes expressing Interferon Gamma (IFNG) and Interleukin 4 (IL4) and the level of expression of the immunoregulatory transcription factor FOXP3 between pregnant and non-pregnant mares, and between peripheral blood and the endometrium during pregnancy. In a cohort of mares in which peripheral blood lymphocytes were tested during early pregnancy and in the non-pregnant state, there were only slight changes observed during pregnancy. In contrast, comparison of peripheral blood lymphocytes with lymphocytes isolated from the endometrial cups of pregnant mares revealed striking differences in lymphocyte sub-populations. The endometrial cups contained higher numbers of IFNG+ lymphocytes, and lower numbers of lymphocytes expressing IL4. The endometrial cup lymphocytes also had higher numbers of FOXP3+ cells compared to peripheral blood lymphocytes. Taken together, these results strengthen the evidence for a state of split tolerance to trophoblast, and furthermore define sharp differences in immune reactivity during equine pregnancy between peripheral blood lymphocytes and lymphocytes at the maternal-fetal interface. PMID:19876828

  13. Salt splitting using ceramic membranes

    SciTech Connect

    Kurath, D.E.

    1997-10-01

    Many radioactive aqueous wastes in the DOE complex have high concentrations of sodium that can negatively affect waste treatment and disposal operations. Sodium can decrease the durability of waste forms such as glass and is the primary contributor to large disposal volumes. Waste treatment processes such as cesium ion exchange, sludge washing, and calcination are made less efficient and more expensive because of the high sodium concentrations. Pacific Northwest National Laboratory (PNNL) and Ceramatec Inc. (Salt Lake City UT) are developing an electrochemical salt splitting process based on inorganic ceramic sodium (Na), super-ionic conductor (NaSICON) membranes that shows promise for mitigating the impact of sodium. In this process, the waste is added to the anode compartment, and an electrical potential is applied to the cell. This drives sodium ions through the membrane, but the membrane rejects most other cations (e.g., Sr{sup +2}, Cs{sup +}). The charge balance in the anode compartment is maintained by generating H{sup +} from the electrolysis of water. The charge balance in the cathode is maintained by generating OH{sup {minus}}, either from the electrolysis of water or from oxygen and water using an oxygen cathode. The normal gaseous products of the electrolysis of water are oxygen at the anode and hydrogen at the cathode. Potentially flammable gas mixtures can be prevented by providing adequate volumes of a sweep gas, using an alternative reductant or destruction of the hydrogen as it is generated. As H{sup +} is generated in the anode compartment, the pH drops. The process may be operated with either an alkaline (pH>12) or an acidic anolyte (pH <1). The benefits of salt splitting using ceramic membranes are (1) waste volume reduction and reduced chemical procurement costs by recycling of NaOH; and (2) direct reduction of sodium in process streams, which enhances subsequent operations such as cesium ion exchange, calcination, and vitrification.

  14. Wave phenomena in the upstream region of Saturn

    NASA Technical Reports Server (NTRS)

    Orlowski, D. S.; Russell, C. T.; Lepping, R. P.

    1992-01-01

    A search was carried out for the signatures of waves associated with both the electron and the ion foreshocks in the upstream region of Saturn, using magnetic-field data obtained by Voyager 1 and 2 during transit through this region. Two distinct bands of wave activity were found at frequencies around 0.5-mHz and 2-mHz in the upstream region. The two classes of waves differ considerably in their properties: the 0.5-mHz waves are righthanded and strongly elliptically polarized, while the 2-mHz waves are elliptically or circularly polarized in the left-handed sense. It is suggested that the two waves may be associated with two different backstreaming particle distributions, possibly those reflected from the shock and those leaking from the hot magnetic field at frequencies between 90 and 150 mHz.

  15. Turbulence analysis of the Jovian upstream 'wave' phenomenon

    NASA Technical Reports Server (NTRS)

    Smith, C. W.; Goldstein, M. L.; Matthaeus, W. H.

    1983-01-01

    As Voyager 2 approached Jupiter's bow shock, large-amplitude fluctuations were seen in both the magnetic field and plasma fluid velocity. These fluctuations generally coincided with the occurrence of long-lived energetic particle events similar to the upstream waves often observed near the earth's bow shock. In this paper an analysis of the magnetic field and plasma observations using spectral methods is presented. The characteristic spectral features related to the upstream waves are generally seen near 1 mHz. The measured correlation lengths of these fluctuations suggest that they are coherent over only a few wavelengths. The analysis is consistent with the hypothesis that these fluctuations are driven by streaming ions, possibly protons. No evidence for the existence of whistler waves is found. It is argued that some of the observed spectral features suggest that dynamical turbulent processes are occurring in the uptream wave region, including a possible observation of an inverse cascade of magnetic helicity to large spatial scales.

  16. Coherence lengths of upstream ULF waves - Dual ISEE observations

    NASA Technical Reports Server (NTRS)

    Le, G.; Russell, C. T.; Orlowski, D. S.

    1993-01-01

    We have used high time resolution simultaneous magnetic field data from the dual ISEE spacecraft to study the coherence lengths of upstream ULF waves. We examine the cross-correlation between ISEE 1 and 2 observations for different spacecraft separations and determine the coherence lengths for upstream 30-second waves, 3-second waves, and one-Hz waves. We find that the observed coherence lengths are consistent with those estimated from the bandwidth of the spectral peak and that these lengths vary markedly from less than 100 km to over 1 R(E). In order to study all these wave phenomena, a multiple spacecraft mission such as the upcoming ESA Cluster mission would need to be capable of assuming a wide variety of possible separations.

  17. Vaccine production: upstream processing with adherent or suspension cell lines.

    PubMed

    Genzel, Yvonne; Rödig, Jana; Rapp, Erdmann; Reichl, Udo

    2014-01-01

    The production of viral vaccines in cell culture can be accomplished with primary, diploid, or continuous (transformed) cell lines. Each cell line, each virus type, and each vaccine preparation require the specific design of upstream and downstream processing. Media have to be selected as well as production vessels, cultivation conditions, and modes of operation. Many viruses only replicate to high titers in adherently growing cells, but similar to processes established for recombinant protein production, an increasing number of suspension cell lines is being evaluated for future use. Here, we describe key issues to be considered for the establishment of large-scale virus production in bioreactors. As an example upstream processing of cell culture-derived influenza virus production is described in more detail for adherently growing and for suspension cells. In particular, use of serum-containing, serum-free, and chemically defined media as well as choice of cultivation vessel are considered. PMID:24297427

  18. Torque fluctuations caused by upstream mean flow and turbulence

    NASA Astrophysics Data System (ADS)

    Farr, T. D.; Hancock, P. E.

    2014-12-01

    A series of studies are in progress investigating the effects of turbine-array-wake interactions for a range of atmospheric boundary layer states by means of the EnFlo meteorological wind tunnel. The small, three-blade model wind turbines drive 4-quadrant motor-generators. Only a single turbine in neutral flow is considered here. The motor-generator current can be measured with adequate sensitivity by means of a current sensor allowing the mean and fluctuating torque to be inferred. Spectra of torque fluctuations and streamwise velocity fluctuations ahead of the rotor, between 0.1 and 2 diameters, show that only the large-scale turbulent motions contribute significantly to the torque fluctuations. Time-lagged cross-correlation between upstream velocity and torque fluctuations are largest over the inner part of the blade. They also show the turbulence to be frozen in behaviour over the 2 diameters upstream of the turbine.

  19. Design of a subsonic airfoil with upstream blowing

    NASA Astrophysics Data System (ADS)

    Il'Inskii, N. B.; Mardanov, R. F.

    2007-10-01

    The problem is solved of designing a symmetric airfoil with upstream blowing opposite to subsonic irrotational steady flow of an inviscid incompressible fluid. The solution relies on Sedov’s idea of a stagnation region developing in the neighborhood of the stagnation point. An iterative solution process is developed, and examples of airfoils are constructed. The numerical results are analyzed, and conclusions are drawn about the effect of blowing parameters on the airfoil geometry and the resultant force acting on the airfoil.

  20. Steepened channels upstream of knickpoints: Controls on relict landscape response

    NASA Astrophysics Data System (ADS)

    Berlin, Maureen M.; Anderson, Robert S.

    2009-09-01

    The morphology of a relict landscape provides important insight into erosion rates and processes prior to base level fall. Fluvial knickpoints are commonly thought to form a leak-proof moving boundary between a rejuvenated landscape below and a relict landscape above. We argue that fluvial rejuvenation may leak farther upstream, depending on the rate and style of knickpoint migration. The outer margin of a relict landscape should therefore be used with caution in tectonic geomorphology studies, as channel steepening upstream of knickpoints could reduce the relict area. We explore the response of the Roan Plateau to knickpoint retreat triggered by late Cenozoic upper Colorado River incision. Multiple knickpoints (100-m waterfalls) separate a low-relief, upper landscape from incised canyons below. Two digital elevation model data sets (10-m U.S. Geological Survey and 1-m Airborne Laser Swath Mapping) indicate steeper channels above waterfalls relative to concave channels farther upstream. The steepened reaches are several kilometers long, correspond to doubling of slope, and exhibit channel narrowing and an increase in hillslope angle. We compare two mechanisms for generating steepened reaches. The first uses a recent model for erosion amplification due to flow acceleration at the waterfall lip. The second acknowledges that waterfall lips may be limited to the outcrop of a resistant formation. Subtle structural warping of the stratigraphy can lead to lowering of the waterfall lip as it retreats, thus lowering base level for upstream channels. Results of numerical modeling experiments suggest the latter mechanism is more consistent with our observations of long, mildly steepened reaches.

  1. 12. Detail, lower chord connection point on upstream side of ...

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

    12. Detail, lower chord connection point on upstream side of truss, showing pinned connection of lower chord eye bars, laced vertical compression member, diagonal eye bar tension members, turnbuckled diagonal counters, and floor beam. Note also timber floor stringers supported by floor beam, and exposed ends of timber deck members visible at left above lower chord eye bar. View to northwest. - Red Bank Creek Bridge, Spanning Red Bank Creek at Rawson Road, Red Bluff, Tehama County, CA

  2. VIEW SOUTH SOUTHWEST LOOKING UPSTREAM FROM ENTRANCE TO LOCKS 35 ...

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

    VIEW SOUTH SOUTHWEST LOOKING UPSTREAM FROM ENTRANCE TO LOCKS 35 AND 71. THE BRIDGE IN THE VIEW IS NOTED FOR ITS EXTRAORDINARY WIDTH (475 FT.) RELATIVE TO ITS MODEST SPAN (116 FT. 10 IN.). WHEN CONSTRUCTED IN 1914 IT WAS CLAIMED TO BE THE WIDEST BRIDGE IN THE WORLD. MAIN STREET CROSSES IT DIAGONALLY, ALONG WITH TWO CROSS STREETS. - New York State Barge Canal, Lockport Locks, Richmond Avenue, Lockport, Niagara County, NY

  3. Interannual variability in bottom-up processes in the upstream range of the California Current system: An isotopic approach

    NASA Astrophysics Data System (ADS)

    El-Sabaawi, Rana W.; Trudel, Marc; Mackas, David L.; Dower, John F.; Mazumder, Asit

    2012-11-01

    The abundance and composition of zooplankton, fish and seabirds show dramatic interannual variability in temperate coastal regions. Understanding links between this variability and bottom-up processes is an important goal for biological oceanographers. Because zooplankton stable isotopes (δ15N and δ13C) are potentially influenced by variability in phytoplankton nutrient utilization, primary production, and zooplankton trophic structure, they have the potential to elucidate links between bottom-up processes, food web structure, and abundance or species composition of higher trophic levels. Here we measure correlations between zooplankton stable isotopes and oceanographic variables in two time series from the west coast of Vancouver Island, upstream of the California Current upwelling system. We then relate interannual variability in zooplankton stable isotopes to interannual variability in zooplankton species composition. Zooplankton stable isotopes show striking patterns of seasonal, regional and interannual variability. A strong positive correlation between annual averages of zooplankton δ15N and sea-surface temperature is evident in both time series. Zooplankton δ15N is also negatively correlated with interannual anomalies of subarctic copepod biomass in both time series. We propose two different mechanisms to explain these correlations: variability in the strength and direction of horizontal advection, or local fluctuations nutrient availability. We conclude that they are most likely caused by local, temperature-driven fluctuations in nitrate concentrations and primary production. We show that the positive correlation between zooplankton δ15N and temperature is widespread, extending to regions outside of the California Current system. Our findings suggest that interannual variability in zooplankton composition is linked with bottom-up variability in nitrate availability and primary production in the upstream portion of the California Current system. Our

  4. A HIGHWAY MODEL FOR THE ADVECTION, DIFFUSION AND CHEMICAL REACTION OF POLLUTANTS RELEASED BY AUTOMOBILES: PART I. ADVECTION AND DIFFUSION OF SF6 TRACER GAS

    EPA Science Inventory

    A two-dimensional, finite-difference model simulating a highway has been developed which is able to handle linear and nonlinear chemical reactions. Transport of the pollutants is accomplished by use of an upstream-flux-corrected algorithm developed at the Naval Research Laborator...

  5. Catalytic Ignition and Upstream Reaction Propagation in Monolith Reactors

    NASA Technical Reports Server (NTRS)

    Struk, Peter M.; Dietrich, Daniel L.; Miller, Fletcher J.; T'ien, James S.

    2007-01-01

    Using numerical simulations, this work demonstrates a concept called back-end ignition for lighting-off and pre-heating a catalytic monolith in a power generation system. In this concept, a downstream heat source (e.g. a flame) or resistive heating in the downstream portion of the monolith initiates a localized catalytic reaction which subsequently propagates upstream and heats the entire monolith. The simulations used a transient numerical model of a single catalytic channel which characterizes the behavior of the entire monolith. The model treats both the gas and solid phases and includes detailed homogeneous and heterogeneous reactions. An important parameter in the model for back-end ignition is upstream heat conduction along the solid. The simulations used both dry and wet CO chemistry as a model fuel for the proof-of-concept calculations; the presence of water vapor can trigger homogenous reactions, provided that gas-phase temperatures are adequately high and there is sufficient fuel remaining after surface reactions. With sufficiently high inlet equivalence ratio, back-end ignition occurs using the thermophysical properties of both a ceramic and metal monolith (coated with platinum in both cases), with the heat-up times significantly faster for the metal monolith. For lower equivalence ratios, back-end ignition occurs without upstream propagation. Once light-off and propagation occur, the inlet equivalence ratio could be reduced significantly while still maintaining an ignited monolith as demonstrated by calculations using complete monolith heating.

  6. Comparison of upstream phenomena at Venus and Earth

    NASA Technical Reports Server (NTRS)

    Strangeway, R. J.; Crawford, G. K.

    1995-01-01

    The region upstream of a planetary bow shock, known as the foreshock, contains a variety of phenomena. Electrons and ions are reflected and energized at the shock. As these stream back upstream, they generate both VLF and ULF waves. Studies of the terrestrial foreshock have provided most of our understanding of these phenomena. However, comparisons with other planetary foreshocks are beneficial, even though the instrumentation used to provide the data may be less sophisticated than that flown on Earth orbiting spacecraft. In particular, maps of the VLF emissions upstream of the Venus bow shock, using data acquired by the Pioneer Venus Orbiter are particularly illuminating. These maps show that the tangent field line is clearly marked by the presence of plasma oscillations. Of additional interest is evidence that the emissions only extend some 15 Venus radii away from the shock, indicating that the emissions are controlled by the shock scale size. Lower frequency ion acoustic waves are observed deep in the ion foreshock. Only close to the shock do both the ion acoustic waves and ULF waves occur simultaneously. The ULF waves mark the ion foreshock boundary where ion beams should be present. The ion acoustic waves tend to be observed further downstream, where diffuse ion distributions are expected to occur. A similar mapping of the terrestrial foreshock, using data from the ISEE-3 spacecraft shows similar results for the electron foreshock. An extensions of this study to include ULF and ion acoustic waves would be helpful.

  7. Density Fluctuations Upstream and Downstream of Interplanetary Shocks

    NASA Astrophysics Data System (ADS)

    Pitňa, A.; Šafránková, J.; Němeček, Z.; Goncharov, O.; Němec, F.; Přech, L.; Chen, C. H. K.; Zastenker, G. N.

    2016-03-01

    Interplanetary (IP) shocks as typical large-scale disturbances arising from processes such as stream-stream interactions or Interplanetary Coronal Mass Ejection (ICME) launching play a significant role in the energy redistribution, dissipation, particle heating, acceleration, etc. They can change the properties of the turbulent cascade on shorter scales. We focus on changes of the level and spectral properties of ion flux fluctuations upstream and downstream of fast forward oblique shocks. Although the fluctuation level increases by an order of magnitude across the shock, the spectral slope in the magnetohydrodynamic range is conserved. The frequency spectra upstream of IP shocks are the same as those in the solar wind (if not spoiled by foreshock waves). The spectral slopes downstream are roughly proportional to the corresponding slopes upstream, suggesting that the properties of the turbulent cascade are conserved across the shock thus, the shock does not destroy the shape of the spectrum as turbulence passes through it. Frequency spectra downstream of IP shocks often exhibit “an exponential decay” in the ion kinetic range that was earlier reported at electron scales in the solar wind or at ion scales in the interstellar medium. We suggest that the exponential shape of ion flux spectra in this range is caused by stronger damping of the fluctuations in the downstream region.

  8. Interaction of upstream flow distortions with high Mach number cascades

    NASA Technical Reports Server (NTRS)

    Englert, G. W.

    1981-01-01

    Features of the interaction of flow distortions, such as gusts and wakes with blade rows of advance type fans and compressors having high tip Mach numbers are modeled. A typical disturbance was assumed to have harmonic time dependence and was described, at a far upstream location, in three orthogonal spatial coordinates by a double Fourier series. It was convected at supersonic relative to a linear cascade described as an unrolled annulus. Conditions were selected so that the component of this velocity parallel to the axis of the turbomachine was subsonic, permitting interaction between blades through the upstream as well as downstream flow media. A strong, nearly normal shock was considered in the blade passages which was allowed curvature and displacement. The flows before and after the shock were linearized relative to uniform mean velocities in their respective regions. Solution of the descriptive equations was by adaption of the Wiener-Hopf technique, enabling a determination of distortion patterns through and downstream of the cascade as well as pressure distributions on the blade and surfaces. Details of interaction of the disturbance with the in-passage shock were discussed. Infuences of amplitude, wave length, and phase of the disturbance on lifts and moments of cascade configurations are presented. Numerical results are clarified by reference to an especially orderly pattern of upstream vertical motion in relation to the cascade parameters.

  9. Upstream versus downstream control of meltwater plumes under ice shelves

    NASA Astrophysics Data System (ADS)

    Wells, Andrew

    2013-11-01

    In many locations the Greenland and Antarctic ice sheets discharge into the ocean through ice shelves floating on top of a warm salty ocean. The turbulent buoyancy-driven flow of meltwater beneath the sloping ice-shelf base enhances heat transfer and provides a feedback on ice melting rates, with consequences for ice sheet dynamics and predictions of sea-level rise. Previous steady-state models of meltwater plumes under ice shelves have solved for the development of flow along the slope from an initial source, corresponding to solely upstream control of the plume dynamics. I re-interpret the plume dynamics embedded within the framework of a time-dependent model, and show that the flow exhibits distinct regimes depending on the source conditions. Solutions with upstream control are physically consistent for certain source conditions, but the plume is influenced by a combination of upstream and downstream conditions in other regions of parameter space. The dynamics are illustrated for flow underneath a two-dimensional ice shelf of initially constant basal slope, and stable attracting states are determined. The implications for modelling meltwater flow under ice shelves are discussed.

  10. Upstream waves simultaneously observed by ISEE and UKS

    NASA Technical Reports Server (NTRS)

    Russell, C. T.; Luhmann, J. G.; Elphic, R. C.; Southwood, D. J.; Smith, M. F.

    1987-01-01

    Measurements obtained in the solar wind by ISEE-2 and the United Kingdom Subsatellite (UKS) have been examined for observations of upstream waves. These data reveal that the waves in the foreshock region are enhanced at all frequencies from at least 0.003 Hz to 0.5 Hz. The wave spectra generally have a spectral peak, but this peak is usually broad and the peak frequency depends on the position of the spacecraft. Generally, the spectra seen at the two spacecraft are most similar at high frequencies and least similar at low frequencies. The geometry of the interaction is displayed in the plane containing the magnetic field, the solar wind velocity, and the spacecraft location. However, this coordinate system does not order all the observed wave properties. It does not clearly explain or order the handedness of the waves, or their direction of propagation. It is clear that the upstream region is inherently three-dimensional. The position-dependent nature of the upstream waves indicates that comparisons between ground-based measurements and in-situ observations must be undertaken with some caution.

  11. Hydraulics of floods upstream of horseshoe canyons and waterfalls

    NASA Astrophysics Data System (ADS)

    Lapotre, Mathieu G. A.; Lamb, Michael P.

    2015-07-01

    Horseshoe waterfalls are ubiquitous in natural streams, bedrock canyons, and engineering structures. Nevertheless, water flow patterns upstream of horseshoe waterfalls are poorly known and likely differ from the better studied case of a one-dimensional linear step because of flow focusing into the horseshoe. This is a significant knowledge gap because the hydraulics at waterfalls controls sediment transport and bedrock incision, which can compromise the integrity of engineered structures and influence the evolution of river canyons on Earth and Mars. Here we develop new semiempirical theory for the spatial acceleration of water upstream of, and the cumulative discharge into, horseshoe canyons and waterfalls. To this end, we performed 110 numerical experiments by solving the 2-D depth-averaged shallow-water equations for a wide range of flood depths, widths and discharges, and canyon lengths, widths and bed gradients. We show that the upstream, normal flow Froude number is the dominant control on lateral flow focusing and acceleration into the canyon head and that focusing is limited when the flood width is small compared to a cross-stream backwater length scale. In addition, for sheet floods much wider than the canyon, flow focusing into the canyon head leads to reduced discharge (and drying in cases) across the canyon sidewalls, which is especially pronounced for canyons that are much longer than they are wide. Our results provide new expectations for morphodynamic feedbacks between floods and topography, and thus canyon formation.

  12. Energetic Particles and Upstream Waves at Co-rotating Shocks

    NASA Astrophysics Data System (ADS)

    Smith, Edward J.; Zhou, Xiaoyan

    2010-03-01

    We report a study of energetic ion acceleration at shocks bounding co-rotating interaction regions (CIRs). Archived data obtained by Ulysses magnetic field, solar wind and energetic particle investigations at low latitude CIRs have been assembled and analyzed. The statistical relations between various properties of 22 Forward shocks, energetic particles and upstream heliospheric magnetic field fluctuations are presented. No statistically significant correlations are found between the shock compression ratio, r, or the particle intensity, jp, or the energetic particle spectral index, s, and the shock normal-upstream field angle, θBn. Furthermore, a theoretical relation between the particle spectral index and shock compression is not consistent with the observed values of s and r. The particle intensities are poorly correlated with the power in upstream heliospheric magnetic field fluctuations contrary to our preliminary study of fewer shocks. We conclude that many of the expectations of Diffusive Shock Theory are not supported by this data set but it is too early to decide whether some key measurement is missing or the theory needs reconsideration.

  13. Whistler wave bursts upstream of the Uranian bow shock

    NASA Technical Reports Server (NTRS)

    Smith, Charles W.; Goldstein, Melvyn L.; Wong, Hung K.

    1989-01-01

    Observations of magnetic field wave bursts upstream of the Uranian bow shock are reported which were recorded prior to the inbound shock crossing. Three wave types are identified. One exhibits a broad spectral enhancement from a few millihertz to about 50 mHz and is seen from 17 to 10 hr prior to the inbound shock crossing. It is argued that these waves are whistler waves that have propagated upstream from the shock. A second wave type has a spacecraft frame frequency between 20 and 40 mHz, is seen only within or immediately upstream of the shock pedestal, is right-hand polarized in the spacecraft frame, and has a typical burst duration of 90 s. The third wave type has a spacecraft frame frequency of about 0.15 Hz, is seen exclusively within the shock pedestal, is left-hand polarized in the spacecraft frame, and has a burst duration lasting up to 4 min. It is argued that the low-frequency bursts are whistler waves with phase speed comparable to, but in excess of, the solar wind speed.

  14. Power Budget Analysis of Colorless Hybrid WDM/TDM-PON Scheme Using Downstream DPSK and Re-modulated Upstream OOK Data Signals

    NASA Astrophysics Data System (ADS)

    Khan, Yousaf; Afridi, Muhammad Idrees; Khan, Ahmed Mudassir; Rehman, Waheed Ur; Khan, Jahanzeb

    2014-09-01

    Hybrid wavelength-division multiplexed/time-division multiplexed passive optical access networks (WDM/TDM-PONs) combine the advance features of both WDM and TDM PONs to provide a cost-effective access network solution. We demonstrate and analyze the transmission performances and power budget issues of a colorless hybrid WDM/TDM-PON scheme. A 10-Gb/s downstream differential phase shift keying (DPSK) and remodulated upstream on/off keying (OOK) data signals are transmitted over 25 km standard single mode fiber. Simulation results show error free transmission having adequate power margins in both downstream and upstream transmission, which prove the applicability of the proposed scheme to future passive optical access networks. The power budget confines both the PON splitting ratio and the distance between the Optical Line Terminal (OLT) and Optical Network Unit (ONU).

  15. Improving estimates of ecosystem metabolism by reducing effects of tidal advection on dissolved oxygen time series-Abstract

    EPA Science Inventory

    Continuous time series of dissolved oxygen (DO) have been used to compute estimates of metabolism in aquatic ecosystems. Central to this open water or "Odum" method is the assumption that the DO time is not strongly affected by advection and that effects due to advection or mixin...

  16. Analytical solution of the advection-diffusion transport equation using a change-of-variable and integral transform technique

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This paper presents a formal exact solution of the linear advection-diffusion transport equation with constant coefficients for both transient and steady-state regimes. A classical mathematical substitution transforms the original advection-diffusion equation into an exclusively diffusive equation. ...

  17. Analytical solutions of the one-dimensional advection-dispersion solute transport equation subject to time-dependent boundary conditions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Analytical solutions of the advection-dispersion solute transport equation remain useful for a large number of applications in science and engineering. In this paper we extend the Duhamel theorem, originally established for diffusion type problems, to the case of advective-dispersive transport subj...

  18. Transferring Goods or Splitting a Resource Pool

    ERIC Educational Resources Information Center

    Dijkstra, Jacob; Van Assen, Marcel A. L. M.

    2008-01-01

    We investigated the consequences for exchange outcomes of the violation of an assumption underlying most social psychological research on exchange. This assumption is that the negotiated direct exchange of commodities between two actors (pure exchange) can be validly represented as two actors splitting a fixed pool of resources (split pool…

  19. Precision aligned split V-block

    DOEpatents

    George, Irwin S.

    1984-01-01

    A precision aligned split V-block for holding a workpiece during a milling operation having an expandable frame for allowing various sized workpieces to be accommodated, is easily secured directly to the mill table and having key lugs in one base of the split V-block that assures constant alignment.

  20. Splitting and Projection at Work in Schools

    ERIC Educational Resources Information Center

    Dunning, Gerald; James, Chris; Jones, Nicola

    2005-01-01

    Purpose: The purpose of this paper is to report research into the social defence of splitting and projection in schools. In splitting and projection, organisational members separate their unbearable feelings from the more acceptable ones and project them, typically towards other individuals and groups. Design/methodology/approach: The research was…

  1. Tracking Water Absorption in Split Susceptible Blueberries

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rain related fruit splitting in blueberries has been a problem for commercial blueberry growers in the Southeastern US. The presence of split berries can cause an entire batch of berries to be rejected. Rejection of batches can be devastating to the growers and their income. Previous studies ha...

  2. 7 CFR 51.2002 - Split shell.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ....2002 Split shell. Split shell means a shell having any crack which is open and conspicuous for a... Practices), DEPARTMENT OF AGRICULTURE REGULATIONS AND STANDARDS UNDER THE AGRICULTURAL MARKETING ACT OF 1946 AND THE EGG PRODUCTS INSPECTION ACT FRESH FRUITS, VEGETABLES AND OTHER PRODUCTS 1 2...

  3. Combining split-beam and dual-frequency identification sonars to estimate abundance of anadromous fishes in the Roanoke River, North Carolina

    USGS Publications Warehouse

    Hughes, Jacob B.; Hightower, Joseph E.

    2015-01-01

    Riverine hydroacoustic techniques are an effective method for evaluating abundance of upstream migrating anadromous fishes. To use these methods in the Roanoke River, North Carolina, at a wide site with uneven bottom topography, we used a combination of split-beam sonar and dual-frequency identification sonar (DIDSON) deployments. We aimed a split-beam sonar horizontally to monitor midchannel and near-bottom zones continuously over the 3-month spring monitoring periods in 2010 and 2011. The DIDSON was rotated between seven cross-channel locations (using a vertical aim) and nearshore regions (using horizontal aims). Vertical deployment addressed blind spots in split-beam coverage along the bottom and provided reliable information about the cross-channel and vertical distributions of upstream migrants. Using a Bayesian framework, we modeled sonar counts within four cross-channel strata and apportioned counts by species using species proportions from boat electrofishing and gill netting. Modeled estimates (95% credible intervals [CIs]) of total upstream migrants in 2010 and 2011 were 2.5 million (95% CI, 2.4–2.6 million) and 3.6 million (95% CI, 3.4–3.9 million), respectively. Results indicated that upstream migrants are extremely shore- and bottom-oriented, suggesting nearshore DIDSON monitoring improved the accuracy and precision of our estimates. This monitoring protocol and model may be widely applicable to river systems regardless of their cross-sectional width or profile.

  4. An experimental demonstration for carrier reused bidirectional PON system with adaptive modulation DDO-OFDM downstream and QPSK upstream signals.

    PubMed

    Yan, Jhih-Heng; Chen, You-Wei; Shen, Kuan-Heng; Feng, Kai-Ming

    2013-11-18

    A light source centralized bidirectional passive optical network (PON) system based on multiband direct-detection optical orthogonal frequency division multiplexing (DDO-OFDM) downstream and quadrature phase-shift keying (QPSK) upstream is experimentally demonstrated. By introducing a simple optical single-side band (SSB) filter at the optical network unit (ONU), all the desired signal bands will be immune from the deleterious signal-signal beating interference (SSBI) noise with only single-end direct-detection scheme. An adaptive modulation configuration is employed to enhance the entire downstream throughput which results in a 150-Gbps downstream data rate with a single optical carrier. In the upstream direction, by recycling the clean downstream optical carrier, a 12.5 Gb/s QPSK format with coherent receiving mechanism in central office is adopted for better receiving sensitivity and dispersion tolerance. With the power enhancement by the long-reach PON architecture, the downstream splitting ratio can achieve as high as 1:1024. PMID:24514327

  5. The Impact of Upstream Flow on the Atmospheric Boundary Layer in a Valley on a Mountainous Island

    NASA Astrophysics Data System (ADS)

    Adler, Bianca; Kalthoff, Norbert

    2016-03-01

    Comprehensive measurements on the mountainous island of Corsica were used to investigate how the mountain atmospheric boundary layer (mountain ABL) in a valley downstream of the main mountain ridge was influenced by the upstream flow. The data used were mainly collected with the mobile observation platform KITcube during the first special observation period of the Hydrological cycle in the Mediterranean Experiment (HyMeX) in 2012 and were based on various in situ, remote sensing and aircraft measurements. Two days in autumn 2012 were analyzed in detail. On these days the mountain ABL evolution was a result of convection and thermally-driven circulations as well as terrain-induced dynamically-driven flows. During periods when dynamically-driven flows were dominant, warm and dry air from aloft with a large-scale westerly wind component was transported downwards into the valley. On one day, these flows controlled the mountain ABL characteristics in a large section of the valley for several hours, while on the other day their impact was observed in a smaller section of the valley for about 1 h only. To explain the observations we considered a theoretical concept based on uniform upstream stratification and wind speed, and calculated the non-dimensional mountain height and the horizontal aspect ratio of the barrier to relate the existing conditions to diagnosed regimes of stratified flow past a ridge. On both days, wave breaking, flow splitting and lee vortices were likely to occur. Besides the upstream conditions, a reduction of stability in the valley seemed to be important for the downward transport to reach the ground. The spatio-temporal structure of such a mountain ABL over complex terrain, which was affected by various interacting flows, differed a lot from that of the classical ABL over homogeneous, flat terrain and it is stressed that the traditional ABL definitions need to be revised when applying them to complex terrain.

  6. Particulate export vs lateral advection in the Antarctic Polar Front (Southern Pacific Ocean)

    NASA Astrophysics Data System (ADS)

    Tesi, T.; Langone, L.; Ravaioli, M.; Capotondi, L.; Giglio, F.

    2012-04-01

    The overarching goal of our study was to describe and quantify the influence of lateral advection relative to the vertical export in the Antarctic Polar Front (Southern Pacific Ocean). In areas where lateral advection of particulate material is significant, budgets of bioactive elements can be inaccurate if fluxes through the water column and to the seabed are exclusively interpreted as passive sinking of particles. However, detailed information on the influence of lateral advection in the water column in the southern ocean is lacking. With this in mind, our study focused between the twilight zone (i.e. mesopelagic) and the benthic nepheloid layer to understand the relative importance of lateral flux with increasing water depth. Measurements were performed south of the Antarctic Polar Front for 1 year (January 10th 1999-January 3rd 2000) at 900, 1300, 2400, and 3700 m from the sea surface. The study was carried out using a 3.5 km long mooring line instrumented with sediment traps, current meters and sensors of temperature and conductivity. Sediment trap samples were characterized via several parameters including total mass flux, elemental composition (organic carbon, total nitrogen, biogenic silica, and calcium carbonate), concentration of metals (aluminum, iron, barium, and manganese), 210Pb activity, and foraminifera taxonomy. High fluxes of biogenic particles were observed in both summer 1999 and 2000 as a result of seasonal algal blooms associated with sea ice retreat and water column stratification. During no-productive periods, several high energy events occurred and resulted in advecting resuspended biogenic particles from flat-topped summits of the Pacific Antarctic Ridge. Whereas the distance between seabed and uppermost sediment traps was sufficient to avoid lateral advection processes, resuspension was significant in the lowermost sediment traps accounting for ~60 and ~90% of the material caught at 2400 and 3700 m, respectively. Samples collected during

  7. Process for photosynthetically splitting water

    SciTech Connect

    Greenbaum, E.

    1982-01-28

    In one form of the invention, hydrogen is produced by providing a reactor containing a body of water. The water contains photolytic material, i.e., photoactive material containing a hydrogen-catalyst. The interior of the reactor is isolated from atmosphere and includes a volume for receiving gases evolved from the body of water. The photolytic material is exposed to light to effect photosynthetic splitting of the water into gaseous hydrogen and oxygen. The gas-receiving volume is continuously evacuated by pumping to promote evolution of gaseous hydrogen and oxygen into that volume and to withdraw them therefrom. In another form of the invention, separation of the hydrogen and oxygen is effected by selectively diffusing the hydrogen through a heated semipermeable membrane in a separation zone while maintaining across the zone a magnetic field gradient biasing the oxygen away from the membrane. In a third form of the invention, the withdrawn gas is contacted with a membrane blocking flow of water vapor to the region for effecting recovery of the hydrogen. In a fourth embodiment, the invention comprises a process for selectively recovering hydrogen from a gas mixture comprising hydrogen and oxygen. The process is conducted in a separation zone and comprises contacting the mixture with a semipermeable membrane effecting selective diffusion of hydrogen while maintaining across the zone a magnetic field gradient effecting movement of oxygen in a direction away from the membrane.

  8. Lightweight electrical connector split backshell

    NASA Technical Reports Server (NTRS)

    Goldman, Elliot (Inventor)

    2009-01-01

    An electrical connector split backshell is provided, comprising two substantially identical backshell halves. Each half includes a first side and a cam projecting therefrom along an axis perpendicular thereto, the cam having an alignment tooth with a constant radius and an engagement section with a radius that increases with angular distance from the alignment tooth. Each half further includes a second side parallel to the first side and a circular sector opening disposed in the second side, the circular sector opening including an inner surface configured as a ramp with a constant radius, the ramp being configured to engage with an engagement section of a cam of the other half, the circular sector opening further including a relieved pocket configured to receive an alignment tooth of the cam of the other half. Each half further includes a back side perpendicular to the first and second sides and a wire bundle notch disposed in the back side, the wire bundle notch configured to align with a wire bundle notch of the other half to form a wire bundle opening. The two substantially identical halves are rotatably coupled by engaging the engagement section of each half to the ramp of the other half.

  9. Innovative solar thermochemical water splitting.

    SciTech Connect

    Hogan, Roy E. Jr.; Siegel, Nathan P.; Evans, Lindsey R.; Moss, Timothy A.; Stuecker, John Nicholas; Diver, Richard B., Jr.; Miller, James Edward; Allendorf, Mark D.; James, Darryl L.

    2008-02-01

    Sandia National Laboratories (SNL) is evaluating the potential of an innovative approach for splitting water into hydrogen and oxygen using two-step thermochemical cycles. Thermochemical cycles are heat engines that utilize high-temperature heat to produce chemical work. Like their mechanical work-producing counterparts, their efficiency depends on operating temperature and on the irreversibility of their internal processes. With this in mind, we have invented innovative design concepts for two-step solar-driven thermochemical heat engines based on iron oxide and iron oxide mixed with other metal oxides (ferrites). The design concepts utilize two sets of moving beds of ferrite reactant material in close proximity and moving in opposite directions to overcome a major impediment to achieving high efficiency--thermal recuperation between solids in efficient counter-current arrangements. They also provide inherent separation of the product hydrogen and oxygen and are an excellent match with high-concentration solar flux. However, they also impose unique requirements on the ferrite reactants and materials of construction as well as an understanding of the chemical and cycle thermodynamics. In this report the Counter-Rotating-Ring Receiver/Reactor/Recuperator (CR5) solar thermochemical heat engine and its basic operating principals are described. Preliminary thermal efficiency estimates are presented and discussed. Our ferrite reactant material development activities, thermodynamic studies, test results, and prototype hardware development are also presented.

  10. Increased risk of oesophageal adenocarcinoma among upstream petroleum workers

    PubMed Central

    Kirkeleit, Jorunn; Riise, Trond; Bjørge, Tone; Moen, Bente E; Bråtveit, Magne; Christiani, David C

    2013-01-01

    Objectives To investigate cancer risk, particularly oesophageal cancer, among male upstream petroleum workers offshore potentially exposed to various carcinogenic agents. Methods Using the Norwegian Registry of Employers and Employees, 24 765 male offshore workers registered from 1981 to 2003 was compared with 283 002 male referents from the general working population matched by age and community of residence. The historical cohort was linked to the Cancer Registry of Norway and the Norwegian Cause of Death Registry. Results Male offshore workers had excess risk of oesophageal cancer (RR 2.6, 95% CI 1.4 to 4.8) compared with the reference population. Only the adenocarcinoma type had a significantly increased risk (RR 2.7, 95% CI 1.0 to 7.0), mainly because of an increased risk among upstream operators (RR 4.3, 95% CI 1.3 to 14.5). Upstream operators did not have significant excess of respiratory system or colon cancer or mortality from any other lifestyle-related diseases investigated. Conclusion We found a fourfold excess risk of oesophageal adenocarcinoma among male workers assumed to have had the most extensive contact with crude oil. Due to the small number of cases, and a lack of detailed data on occupational exposure and lifestyle factors associated with oesophageal adenocarcinoma, the results must be interpreted with caution. Nevertheless, given the low risk of lifestyle-related cancers and causes of death in this working group, the results add to the observations in other low-powered studies on oesophageal cancer, further suggesting that factors related to the petroleum stream or carcinogenic agents used in the production process might be associated with risk of oesophageal adenocarcinoma. PMID:19858535

  11. Electron plasma oscillations upstream of the solar wind termination shock.

    PubMed

    Gurnett, D A; Kurth, W S

    2005-09-23

    Electron plasma oscillations have been detected upstream of the solar wind termination shock by the plasma wave instrument on the Voyager 1 spacecraft. These waves were first observed on 11 February 2004, at a heliocentric radial distance of 91.0 astronomical units, and continued sporadically with a gradually increasing occurrence rate for nearly a year. The last event occurred on 15 December 2004, at 94.1 astronomical units, just before the spacecraft crossed the termination shock. Since then, no further electron plasma oscillations have been observed, consistent with the spacecraft having crossed the termination shock into the heliosheath. PMID:16179470

  12. POSTRANSLATIONAL MODIFICATIONS OF P53: UPSTREAM SIGNALING PATHWAYS.

    SciTech Connect

    ANDERSON,C.W.APPELLA,E.

    2003-10-23

    The p53 tumor suppressor is a tetrameric transcription factor that is posttranslational modified at >20 different sites by phosphorylation, acetylation, or sumoylation in response to various cellular stress conditions. Specific posttranslational modifications, or groups of modifications, that result from the activation of different stress-induced signaling pathways are thought to modulate p53 activity to regulate cell fate by inducing cell cycle arrest, apoptosis, or cellular senescence. Here we review recent progress in characterizing the upstream signaling pathways whose activation in response to various genotoxic and non-genotoxic stresses result in p53 posttranslational modifications.

  13. 2. View of Potomac River at Great Falls looking upstream ...

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

    2. View of Potomac River at Great Falls looking upstream from Observation Tower. The majestic character of this wild and untrammeled spot is vividly shown. Scanty flow is evidenced by light colored normal water line markings on rock formation. Washington Agueduct Dam is shown in upper portion. Maryland on right and Virginia on left. Natives quoted as saying the water was as low or lower than during the drought conditions of 1930. Mr. Horyduzak, Photographer, 1943. - Potowmack Company: Great Falls Canal & Locks, Great Falls, Fairfax County, VA

  14. Hybrid simulation codes with application to shocks and upstream waves

    NASA Technical Reports Server (NTRS)

    Winske, D.

    1985-01-01

    Hybrid codes in which part of the plasma is represented as particles and the rest as a fluid are discussed. In the past few years such codes with particle ions and massless, fluid electrons have been applied to space plasmas, especially to collisionless shocks. All of these simulation codes are one-dimensional and similar in structure, except for how the field equations are solved. The various approaches that are used (resistive Ohm's law, predictor-corrector, Hamiltonian) are described in detail and results from the various codes are compared with examples taken from collisionless shocks and low frequency wave phenomena upstream of shocks.

  15. Swimming upstream: the strengths of women who survive homelessness.

    PubMed

    Montgomery, C

    1994-03-01

    A study of the strengths and personal resources of women who had overcome homelessness revealed that the experience of homelessness for these women was a temporary state of disruption resulting from an effort to free themselves from conditions associated with despair, such as abuse or addictions, and to search for a better life. Personal, interpersonal, and transpersonal categories of strengths were identified that enabled these women to move in a positive direction toward health and self-actualization. The synthesizing metaphor "swimming upstream" describes the stoic determination required to go against the overwhelming negative forces of their environment. PMID:7515608

  16. A balancing domain decomposition method by constraints for advection-diffusion problems

    SciTech Connect

    Tu, Xuemin; Li, Jing

    2008-12-10

    The balancing domain decomposition methods by constraints are extended to solving nonsymmetric, positive definite linear systems resulting from the finite element discretization of advection-diffusion equations. A pre-conditioned GMRES iteration is used to solve a Schur complement system of equations for the subdomain interface variables. In the preconditioning step of each iteration, a partially sub-assembled finite element problem is solved. A convergence rate estimate for the GMRES iteration is established, under the condition that the diameters of subdomains are small enough. It is independent of the number of subdomains and grows only slowly with the subdomain problem size. Numerical experiments for several two-dimensional advection-diffusion problems illustrate the fast convergence of the proposed algorithm.

  17. Perturbation analysis of steady and unsteady electrohydrodynamic chaotic advection inside translating drops

    NASA Astrophysics Data System (ADS)

    Wu, Fan; Vainchtein, Dmitri; Ward, Thomas

    2015-08-01

    A drop translating in the presence of an electric field is studied analytically. The flow is a combination of a Hadamard-Rybczynski and a Taylor circulation due to the translation and electric field, respectively. We consider chaotic advection that is generated by (1) tilting and (2) time-dependent modulation of the electric field. For the analysis we consider small perturbations in time and space to what is otherwise an integrable flow. By using a robust analytical technique we find an adiabatic invariant (AI) for the system by averaging the equations of motion. The chaotic advection is due to quasirandom jumps of the AI after crossing the separatrix of the unperturbed flow. We demonstrate that the asymptotic analysis leads to a set of criteria that can be used to optimize stirring in these systems.

  18. Advective-diffusive motion on large scales from small-scale dynamics with an internal symmetry

    NASA Astrophysics Data System (ADS)

    Marino, Raffaele; Aurell, Erik

    2016-06-01

    We consider coupled diffusions in n -dimensional space and on a compact manifold and the resulting effective advective-diffusive motion on large scales in space. The effective drift (advection) and effective diffusion are determined as a solvability conditions in a multiscale analysis. As an example, we consider coupled diffusions in three-dimensional space and on the group manifold SO(3) of proper rotations, generalizing results obtained by H. Brenner [J. Colloid Interface Sci. 80, 548 (1981), 10.1016/0021-9797(81)90214-9]. We show in detail how the analysis can be conveniently carried out using local charts and invariance arguments. As a further example, we consider coupled diffusions in two-dimensional complex space and on the group manifold SU(2). We show that although the local operators may be the same as for SO(3), due to the global nature of the solvability conditions the resulting diffusion will differ and generally be more isotropic.

  19. Reaction-diffusion-advection approach to spatially localized treadmilling aggregates of molecular motors

    NASA Astrophysics Data System (ADS)

    Yochelis, Arik; Bar-On, Tomer; Gov, Nir S.

    2016-04-01

    Unconventional myosins belong to a class of molecular motors that walk processively inside cellular protrusions towards the tips, on top of actin filament. Surprisingly, in addition, they also form retrograde moving self-organized aggregates. The qualitative properties of these aggregates are recapitulated by a mass conserving reaction-diffusion-advection model and admit two distinct families of modes: traveling waves and pulse trains. Unlike the traveling waves that are generated by a linear instability, pulses are nonlinear structures that propagate on top of linearly stable uniform backgrounds. Asymptotic analysis of isolated pulses via a simplified reaction-diffusion-advection variant on large periodic domains, allows to draw qualitative trends for pulse properties, such as the amplitude, width, and propagation speed. The results agree well with numerical integrations and are related to available empirical observations.

  20. Two-dimensional atmospheric transport and chemistry model - Numerical experiments with a new advection algorithm

    NASA Technical Reports Server (NTRS)

    Shia, Run-Lie; Ha, Yuk Lung; Wen, Jun-Shan; Yung, Yuk L.

    1990-01-01

    Extensive testing of the advective scheme proposed by Prather (1986) has been carried out in support of the California Institute of Technology-Jet Propulsion Laboratory two-dimensional model of the middle atmosphere. The original scheme is generalized to include higher-order moments. In addition, it is shown how well the scheme works in the presence of chemistry as well as eddy diffusion. Six types of numerical experiments including simple clock motion and pure advection in two dimensions have been investigated in detail. By comparison with analytic solutions, it is shown that the new algorithm can faithfully preserve concentration profiles, has essentially no numerical diffusion, and is superior to a typical fourth-order finite difference scheme.

  1. On Vortex Genesis. An Heuristic Model of Convection-Advection Linkages

    NASA Astrophysics Data System (ADS)

    Bouali, S.

    2003-04-01

    We connect to a model of convection roll an appropriate feedback loop (i.e., the advection retroaction) which unfolds a wide range of vorticity behavior. The 3D numerical computations display the conservative aerologic flows of waterspouts and tropical cyclones. Moreover, several simulations exhibit the singular topology of the structure of cyclones eventually trapped in period-2 orbit. On the other hand, additional advection linkages provide our dynamical system with an explicative proof of the tornadogenesis. These amendements modify the model. The airflows are now dissipatives and we investigate the kinematics of these short life span phenomena. The extended model leads the trajectories of air pockets to one or more vortices. The downbursts and microbursts described in the Fujita classification are also simulated. Our heuristic dynamical system lays the foundation of an unified modelisation of vortices. Theory and Direct Numerical Simulation of the vortex genesis are associated in a new perspective.

  2. A study of turbulent transport of an advective nature in a fluid plasma

    NASA Astrophysics Data System (ADS)

    Min, Byunghoon; An, Chan-Yong; Kim, Chang-Bae

    2014-08-01

    The advective nature of the electrostatic turbulent flux of plasma energy in Fourier space is studied numerically in a nearly adiabatic state. Such a state is represented by the Hasegawa-Mima equation, which is driven by a noise that may model the destabilization due to the phase mismatch of the plasma density and the electric potential. The noise is assumed to be Gaussian and not to be invariant under reflection along a direction ŝ. The flux density induced by such noise is found to be anisotropic: While it is random along ŝ, it is not along the perpendicular direction ŝ ⊥, and the flux is not diffusive. The renormalized response may be approximated as advective, with the velocity being proportional to ( kρ s )2, in the Fourier space.

  3. Multi-moment advection scheme in three dimension for Vlasov simulations of magnetized plasma

    SciTech Connect

    Minoshima, Takashi; Matsumoto, Yosuke; Amano, Takanobu

    2013-03-01

    We present an extension of the multi-moment advection scheme [T. Minoshima, Y. Matsumoto, T. Amano, Multi-moment advection scheme for Vlasov simulations, Journal of Computational Physics 230 (2011) 6800–6823] to the three-dimensional case, for full electromagnetic Vlasov simulations of magnetized plasma. The scheme treats not only point values of a profile but also its zeroth to second order piecewise moments as dependent variables, and advances them on the basis of their governing equations. Similar to the two-dimensional scheme, the three-dimensional scheme can accurately solve the solid body rotation problem of a gaussian profile with little numerical dispersion or diffusion. This is a very important property for Vlasov simulations of magnetized plasma. We apply the scheme to electromagnetic Vlasov simulations. Propagation of linear waves and nonlinear evolution of the electron temperature anisotropy instability are successfully simulated with a good accuracy of the energy conservation.

  4. A traceable physical calibration of the vertical advection-diffusion equation for modeling ocean heat uptake

    NASA Astrophysics Data System (ADS)

    Huber, Markus; Tailleux, Remi; Ferreira, David; Kuhlbrodt, Till; Gregory, Jonathan

    2015-04-01

    The classic vertical advection-diffusion (VAD) balance is a central concept in studying the ocean heat budget, in particular in simple climate models (SCMs). Here we present a new framework to calibrate the parameters of the VAD equation to the vertical ocean heat balance of two fully-coupled climate models that is traceable to the models' circulation as well as to vertical mixing and diffusion processes. Based on temperature diagnostics, we derive an effective vertical velocity w∗ and turbulent diffusivity kν∗ for each individual physical process. In steady state, we find that the residual vertical velocity and diffusivity change sign in middepth, highlighting the different regional contributions of isopycnal and diapycnal diffusion in balancing the models' residual advection and vertical mixing. We quantify the impacts of the time evolution of the effective quantities under a transient 1% CO2 simulation and make the link to the parameters of currently employed SCMs.

  5. Numerical advection algorithms and their role in atmospheric transport and chemistry models

    NASA Technical Reports Server (NTRS)

    Rood, Richard B.

    1987-01-01

    During the last 35 years, well over 100 algorithms for modeling advection processes have been described and tested. This review summarizes the development and improvements that have taken place. The nature of the errors caused by numerical approximation to the advection equation are highlighted. Then the particular devices that have been proposed to remedy these errors are discussed. The extensive literature comparing transport algorithms is reviewed. Although there is no clear cut 'best' algorithm, several conclusions can be made. Spectral and pseudospectral techniques consistently provide the highest degree of accuracy, but expense and difficulties assuring positive mixing ratios are serious drawbacks. Schemes which consider fluid slabs bounded by grid points (volume schemes), rather than the simple specification of constituent values at the grid points, provide accurate positive definite results.

  6. Estimation and correction of advection effects with single and multiple, conventional and Doppler radars

    NASA Technical Reports Server (NTRS)

    Gal-Chen, T.

    1981-01-01

    The laws of fluid motion are invariant under a Gallilean transformation. For a perfect observing system, the data analysis should, therefore, also be invariant under a Gallilean transformation. This invariance is often not preserved in practical observing systems. In this connection, it is often advisable to perform mesoscale analysis in a frame moving with respect to the earth's surface. In the present investigation the velocity of such a frame is referred to as an advection velocity. The investigation is concerned with remaining problems regarding the Gallilean transformation. The establishment of a frame of reference for the achievement of maximum coherence is considered, taking into account the case of given nonsimultaneous observations of scalars or Cartesian vectors. It is found that advection speed can be estimated objectively if a scalar or Cartesian vector can be observed directly and if, in addition, the time and position of each observation is approximately known.

  7. Sasaki's variational optimization analysis of temperature and moisture advection in a severe storm environment

    NASA Technical Reports Server (NTRS)

    Mcfarland, M. J.

    1975-01-01

    Temperature and moisture advection patterns of dry air intrusion were analyzed by a variational optimization method to relate mesoscale advection to a severe thunderstorm environment. The analysis results presented here were obtained from a case study, May 26, 1973, when a tornado squall line developed in Oklahoma in conjunction with a clearly delineated dry air intrusion. Observations from the synoptic upper air network were used for inputs of horizontal wind components, potential temperature, and mixing ratio at each 50 mb increment from 950 to 100 mb. An objective analysis was performed to assign values of the variables to grid points of a 15 x 14 horizontal grid with approximate 125 km grid spacing at each pressure level. After the analysis the data fields were smoothed using a variational formalism.

  8. CDF Solutions of Advection-Reaction equations with uncertain parameters (Invited)

    NASA Astrophysics Data System (ADS)

    Boso, F.; Tartakovsky, D. M.

    2013-12-01

    Flow and transport models are affected by parametric uncertainty. Quantitative forecasting of such processes in natural porous media are especially prone to uncertainty because of the inaccessibility and multi-scale nature of the subsurface. We consider a reduced-complexity stochastic transport system which takes into account advection and nonlinear reactions in advection-reaction equations (AREs) with uncertain (random) velocity and reaction parameters. We derive a deterministic equation that governs the evolution of cumulative distribution function (CDF) of a solution of the underlying ARE. Although requiring closure, this differential equation benefits from uniquely defined boundary and initial conditions and can be solved with classic techniques. Here we analyze the accuracy and robustness of the large-eddy-diffusivity closure by comparison with Monte Carlo simulations for different correlation structures and parameters.

  9. Improving Scatterometry Retrievals of Wind in Hurricanes Using Non-Simultaneous Passive Microwave Estimates of Precipitation and a Split-Step Advection/Convection Model

    NASA Astrophysics Data System (ADS)

    Fore, Alex; Haddad, Ziad S.; Krishnamurti, T. N.; Rodgridez, Ernesto

    2012-03-01

    One of the current problems in the accurate estimation of over-ocean wind from scatterometry observations is the proper accounting for precipitation. Specific cases such as hurricanes are particularly difficult, because precipitation in the eye wall and rain bands can be quite heavy, and therefore, affect the scatterometer signatures so drastically that a category-4 hurricane can appear, to the scatterometer, to have category-1 winds. We have developed an approach to infer and account for the signature of the precipitation from non-simultaneous passive-microwave measurements of rain, with the help of geostationary IR measurements. In this note, we describe the basic approach, and the results of applying it to the data taken by the Tropical Rainfall Measurement Mission Microwave Imager measurements several hours before and after the QuikSCAT observation of Hurricane Rita in September 2005. We also describe how we are enhancing the approach with more realism in the assimilation of the IR information.

  10. Scyphozoa in the Bornholm Basin (central Baltic Sea) The role of advection

    NASA Astrophysics Data System (ADS)

    Barz, Kristina; Hinrichsen, Hans-Harald; Hirche, Hans-Jürgen

    2006-04-01

    The usual absence of ephyrae and late appearance of medusae of the Scyphozoa Aurelia aurita and Cyanea capillata in the Bornholm Basin (BB; central Baltic Sea) indicate that these species are not strobilating in the region and their presence depends on advection. To study their potential origin we compared drift from historically known strobilation areas derived from a circulation model with spatial distributions observed during 19 cruises in the BB during 2002 and 2003. The model results are in good accordance with the field observations. According to the model results inter-annual differences in the timing of first appearance and life stage at appearance of A. aurita were clearly related to differences in the hydrodynamic regime during the investigation periods. During the stagnation regime in 2002 young medusae occurred first in June in the BB. In contrast, in 2003 fast transport due to several inflow events advected ephyrae released between January and March in the western Baltic already in April to the BB. Although the Gullmar Fjord (western Sweden) is the nearest known strobilation area for C. capillata, the model did not support advection from there in numbers explaining the occurrence of this species in the BB in 2002 and 2003. If the model works adequately in this regions we have to assume that the Gullmar Fjord is not a main source region of C. capillata in the BB, but other strobilation areas in the Kattegat or the North Sea appear more important. Our results imply that advection and inflow events are critical for the occurrence and distribution of early stages of jellyfish in the central Baltic Sea. They demonstrate the potential of circulation models as tools to study the effect of long-range transport on the spatial composition of these organisms.

  11. Approximate Solution of Time-Fractional Advection-Dispersion Equation via Fractional Variational Iteration Method

    PubMed Central

    İbiş, Birol

    2014-01-01

    This paper aims to obtain the approximate solution of time-fractional advection-dispersion equation (FADE) involving Jumarie's modification of Riemann-Liouville derivative by the fractional variational iteration method (FVIM). FVIM provides an analytical approximate solution in the form of a convergent series. Some examples are given and the results indicate that the FVIM is of high accuracy, more efficient, and more convenient for solving time FADEs. PMID:24578662

  12. Shadowing and the role of small diffusivity in the chaotic advection of scalars

    NASA Technical Reports Server (NTRS)

    Klapper, I.

    1992-01-01

    Using techniques from shadowing theory, the solution of the scalar advection-diffusion equation is studied. It is shown that, under certain circumstances, the effect of small scalar diffusivity is to smooth the zero-diffusivity solution by averaging local fine-scaled structure against a Gaussian. The method of study depends on shadowing and thus fails for nonuniformly stretching systems, its failure suggesting the ways in which the effects of asymptotically small molecular diffusion can become nonlocal in chaotic fluid flows.

  13. Carbon dioxide seasonality in dynamically ventilated caves: the role of advective fluxes

    NASA Astrophysics Data System (ADS)

    Lang, Marek; Faimon, Jiří; Godissart, Jean; Ek, Camille

    2016-07-01

    The seasonality in cave CO2 levels was studied based on (1) a new data set from the dynamically ventilated Comblain-au-Pont Cave (Dinant Karst Basin, Belgium), (2) archive data from Moravian Karst caves, and (3) published data from caves worldwide. A simplified dynamic model was proposed for testing the effect of all conceivable CO2 fluxes on cave CO2 levels. Considering generally accepted fluxes, i.e., the direct diffusive flux from soils/epikarst, the indirect flux derived from dripwater degassing, and the input/output fluxes linked to cave ventilation, gives the cave CO2 level maxima of 1.9 × 10-2 mol m-3 (i.e., ˜ 440 ppmv), which only slightly exceed external values. This indicates that an additional input CO2 flux is necessary for reaching usual cave CO2 level maxima. The modeling indicates that the additional flux could be a convective advective CO2 flux from soil/epikarst driven by airflow (cave ventilation) and enhanced soil/epikarstic CO2 concentrations. Such flux reaching up to 170 mol s-1 is capable of providing the cave CO2 level maxima up to 3 × 10-2 mol m-3 (70,000 ppmv). This value corresponds to the maxima known from caves worldwide. Based on cave geometry, three types of dynamic caves were distinguished: (1) the caves with the advective CO2 flux from soil/epikarst at downward airflow ventilation mode, (2) the caves with the advective soil/epikarstic flux at upward airflow ventilation mode, and (3) the caves without any soil/epikarstic advective flux. In addition to CO2 seasonality, the model explains both the short-term and seasonal variations in δ13C in cave air CO2.

  14. Advective transport and decomposition of chain-forming planktonic diatoms in permeable sediments

    NASA Astrophysics Data System (ADS)

    Ehrenhauss, Sandra; Huettel, Markus

    2004-09-01

    In laboratory chamber experiments we demonstrate that permeable sediments (>7×10 -12 m 2) exposed to boundary flows filter chain-forming coastal bloom diatoms ( Skeletonema costatum and Thalassiosira rotula) from the water column, causing rapid transfer of fresh organic particulate matter into sediment layers as deep as 5 cm within 72 h. The penetration depth of the diatoms depends on the permeability of the bed and the length of the chains. Long chains were not transported as deep into the sediment as short chains or single cells. The fast advective transfer of phytoplankton cells into sandy sediments may be an important process facilitating organic matter uptake and preventing resuspension of deposited organic material in high-energy coastal environments. High advective flushing rates in medium- and coarse-grained sandy sediments enhanced the mineralisation of the trapped diatoms (2300 to 3200 μmol C m -2 d -1), stimulated benthic oxygen consumption (2300 to 3000 μmol O 2 m -2 d -1), as well as nitrification (up to 20 μmol NO 3- m -2 d -1), relative to sediment where diffusion dominated the solute exchange. Advective solute exchange rates that increase with increasing permeability prevent the accumulation of Si(OH) 4 near the dissolving frustules and in the pore water, leading to an effective recycling of dissolved silica to the production process in the water column (95 to 101 μmol Si(OH) 4 m -2 d -1). This process may also enhance dissolution rates of the deposited opal in coarse-grained sands by maintaining higher degrees of undersaturation than in fine-grained sediments. Our results suggest that advective filtration of planktonic diatoms into permeable sediments increases mineralisation and recycling of Si(OH) 4 and organic matter in high energetic shelf areas.

  15. Approximate solution of time-fractional advection-dispersion equation via fractional variational iteration method.

    PubMed

    Ibiş, Birol; Bayram, Mustafa

    2014-01-01

    This paper aims to obtain the approximate solution of time-fractional advection-dispersion equation (FADE) involving Jumarie's modification of Riemann-Liouville derivative by the fractional variational iteration method (FVIM). FVIM provides an analytical approximate solution in the form of a convergent series. Some examples are given and the results indicate that the FVIM is of high accuracy, more efficient, and more convenient for solving time FADEs. PMID:24578662

  16. A Lagrangian-Eulerian finite element method with adaptive gridding for advection-dispersion problems

    SciTech Connect

    Ijiri, Y.; Karasaki, K.

    1994-02-01

    In the present paper, a Lagrangian-Eulerian finite element method with adaptive gridding for solving advection-dispersion equations is described. The code creates new grid points in the vicinity of sharp fronts at every time step in order to reduce numerical dispersion. The code yields quite accurate solutions for a wide range of mesh Peclet numbers and for mesh Courant numbers well in excess of 1.

  17. POD-Galerkin advection model for convective flow: application to a flapping rectangular supersonic jet

    NASA Astrophysics Data System (ADS)

    Jaunet, V.; Collin, E.; Delville, J.

    2016-05-01

    This article describes a model obtained by applying proper orthogonal decomposition to the advection equation. The resulting set of equations links the POD modes, their temporal and spatial derivatives and the flow convection velocity. It provides a technique to calculate the convection velocity of coherent structures. It follows, from the model, that a priori knowledge of the convection velocity suffices to construct a dynamical model of the flow. This is demonstrated using experimental data.

  18. A Crater Split In Two

    NASA Technical Reports Server (NTRS)

    2003-01-01

    [figure removed for brevity, see original site]

    Released 23 September 2003

    A 22 km-diameter crater has been sliced by the tectonic forces that produced the rift known as Sirenum Fossae. The orientation of this rift is roughly radial to the great Tharsis volcano Arsia Mons, probably indicating a link between the formation of the rift and the volcano. Note how the rift cuts through a jumble of mounds on the floor of the crater. This indicates a sequence of events beginning with the formation of the crater followed by an infilling of material that was then eroded into the mounds and ultimately split open by the shifting martian crust.

    Image information: VIS instrument. Latitude -29.7, Longitude 211.7 East (148.3 West). 19 meter/pixel resolution.

    Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.

    NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.

  19. Communication: Tunnelling splitting in the phosphine molecule.

    PubMed

    Sousa-Silva, Clara; Tennyson, Jonathan; Yurchenko, Sergey N

    2016-09-01

    Splitting due to tunnelling via the potential energy barrier has played a significant role in the study of molecular spectra since the early days of spectroscopy. The observation of the ammonia doublet led to attempts to find a phosphine analogous, but these have so far failed due to its considerably higher barrier. Full dimensional, variational nuclear motion calculations are used to predict splittings as a function of excitation energy. Simulated spectra suggest that such splittings should be observable in the near infrared via overtones of the ν2 bending mode starting with 4ν2. PMID:27608982

  20. A Petroleum Vapor Intrusion Model Involving Upward Advective Soil Gas Flow Due to Methane Generation.

    PubMed

    Yao, Yijun; Wu, Yun; Wang, Yue; Verginelli, Iason; Zeng, Tian; Suuberg, Eric M; Jiang, Lin; Wen, Yuezhong; Ma, Jie

    2015-10-01

    At petroleum vapor intrusion (PVI) sites at which there is significant methane generation, upward advective soil gas transport may be observed. To evaluate the health and explosion risks that may exist under such scenarios, a one-dimensional analytical model describing these processes is introduced in this study. This new model accounts for both advective and diffusive transport in soil gas and couples this with a piecewise first-order aerobic biodegradation model, limited by oxygen availability. The predicted results from the new model are shown to be in good agreement with the simulation results obtained from a three-dimensional numerical model. These results suggest that this analytical model is suitable for describing cases involving open ground surface beyond the foundation edge, serving as the primary oxygen source. This new analytical model indicates that the major contribution of upward advection to indoor air concentration could be limited to the increase of soil gas entry rate, since the oxygen in soil might already be depleted owing to the associated high methane source vapor concentration. PMID:26322369

  1. Modulated point-vortex pairs on a rotating sphere: Dynamics and chaotic advection

    NASA Astrophysics Data System (ADS)

    Drótos, Gábor; Tél, Tamás; Kovács, Gergely

    2013-06-01

    The dynamics of modulated point-vortex pairs is investigated on a rotating sphere, where modulation is chosen to reflect the conservation of angular momentum (potential vorticity). For sufficiently close vortices (dipoles) the trajectories of their center-of-mass are shown to correspond to those of a point particle moving freely on a rotating sphere. For finite size vortex pairs, a qualitative similarity to the geodesic dynamics is found. The advection dynamics generated by vortex pairs on a rotating sphere is found to be chaotic. In the short time dynamics we point out a transition from closed to open chaotic advection, which implies that the transport properties of the flow might drastically be altered by changing the initial conditions of the pair on the sphere. Due to spherical topology, for long times, even the open advection patterns are found to gradually cross over to that corresponding to a homogeneous closed mixing. This pattern extends along a zonal band, whereas short term closed mixing remains always bounded to the moving pair.

  2. Parallel simulation of particle transport in an advection field applied to volcanic explosive eruptions

    NASA Astrophysics Data System (ADS)

    Künzli, Pierre; Tsunematsu, Kae; Albuquerque, Paul; Falcone, Jean-Luc; Chopard, Bastien; Bonadonna, Costanza

    2016-04-01

    Volcanic ash transport and dispersal models typically describe particle motion via a turbulent velocity field. Particles are advected inside this field from the moment they leave the vent of the volcano until they deposit on the ground. Several techniques exist to simulate particles in an advection field such as finite difference Eulerian, Lagrangian-puff or pure Lagrangian techniques. In this paper, we present a new flexible simulation tool called TETRAS (TEphra TRAnsport Simulator) based on a hybrid Eulerian-Lagrangian model. This scheme offers the advantages of being numerically stable with no numerical diffusion and easily parallelizable. It also allows us to output particle atmospheric concentration or ground mass load at any given time. The model is validated using the advection-diffusion analytical equation. We also obtained a good agreement with field observations of the tephra deposit associated with the 2450 BP Pululagua (Ecuador) and the 1996 Ruapehu (New Zealand) eruptions. As this kind of model can lead to computationally intensive simulations, a parallelization on a distributed memory architecture was developed. A related performance model, taking into account load imbalance, is proposed and its accuracy tested.

  3. A Comparative Study of Indoor Radon Contributed by Diffusive and Advective Transport through Intact Concrete

    NASA Astrophysics Data System (ADS)

    Chauhan, R. P.; Kumar, Amit

    The present work is aimed that out of diffusive and advective transport which is dominant process for indoor radon entry under normal room conditions. For this purpose the radon diffusion coefficient and permeability of concrete were measured by specially designed experimental set up. The radon diffusion coefficient of concrete was measured by continuous radon monitor. The measured value was (3.78 ± 0.39)×10-8 m2/s and found independent of the radon gas concentration in source chamber. The radon permeability of concrete varied between 1.85×10-17 to 1.36×10-15 m2 for the bulk pressure difference fewer than 20 Pa to 73.3 kPa. From the measured diffusion coefficient and absolute permeability, the radon flux from the concrete surface having concentrations gradient 12-40 kBq/m3 and typical floor thickness 0.1 m was calculated by the application of Fick and Darcy laws. Using the measured flux attributable to diffusive and advective transport, the indoor radon concentration for a typical Indian model room having dimension (5×6×7) m3 was calculated under average room ventilation (0.63 h-1). The results showed that the contribution of diffusive transport through intact concrete is dominant over the advective transport, as expected from the low values of concrete permeability.

  4. Advective pore water input of nutrients to the Satilla River Estuary, Georgia, USA

    NASA Astrophysics Data System (ADS)

    Jahnke, R. A.; Alexander, C. R.; Kostka, J. E.

    2003-03-01

    In situ benthic flux measurements, pore water nutrient profiles, water column nutrient distributions, sediment grain size distributions and side-scan sonar observations suggest that advective transport of pore waters may be a major input pathway of nutrients into the Satilla River Estuary (coastal Georgia, USA). In situ benthic chamber incubations demonstrate the occurrence of highly variable, but occasionally very large sea floor fluxes of silicate, phosphate, and ammonium. Locally occurring benthic microbial mineralization of organic matter, as estimated by S 35-sulphate reduction rate measurements, is insufficient to support these large fluxes. We hypothesize that the observed interlayering of permeable, sandy sediments with fine-grained, organic-rich sediments in the estuary provides conduits for advective transport of pore water constituents out of the sediments. Because permeable layers may extend significant distances beneath the salt marsh, the large fluxes observed may be supported by remineralization occurring over large areas adjacent to the estuary. Advective transport may be induced by pressure gradients generated by a variety of processes, including landward recharge by meteoric or rain waters if sand layers extend far enough into the maritime coastal lands. Alternatively, tidal variations across the salt marsh sediment surface may hydraulically pump water through the sediment system. Because these fluxes appear to be concentrated into small layers, this source may be a significant input of nutrients to the estuary even if permeable, sandy layers comprise a very small proportion of the seabed.

  5. Modulated point-vortex pairs on a rotating sphere: dynamics and chaotic advection.

    PubMed

    Drótos, Gábor; Tél, Tamás; Kovács, Gergely

    2013-06-01

    The dynamics of modulated point-vortex pairs is investigated on a rotating sphere, where modulation is chosen to reflect the conservation of angular momentum (potential vorticity). For sufficiently close vortices (dipoles) the trajectories of their center-of-mass are shown to correspond to those of a point particle moving freely on a rotating sphere. For finite size vortex pairs, a qualitative similarity to the geodesic dynamics is found. The advection dynamics generated by vortex pairs on a rotating sphere is found to be chaotic. In the short time dynamics we point out a transition from closed to open chaotic advection, which implies that the transport properties of the flow might drastically be altered by changing the initial conditions of the pair on the sphere. Due to spherical topology, for long times, even the open advection patterns are found to gradually cross over to that corresponding to a homogeneous closed mixing. This pattern extends along a zonal band, whereas short term closed mixing remains always bounded to the moving pair. PMID:23848782

  6. Advection-condensation of water vapor with coherent stirring: a stochastic approach

    NASA Astrophysics Data System (ADS)

    Tsang, Yue-Kin; Vanneste, Jacques; Vallis, Geoffrey

    2015-11-01

    The dynamics of atmospheric water is an essential ingredient of weather and climate. Water vapor, in particular, is an important greenhouse gas whose distribution has a strong impact on climate. To gain insight into the factors controlling the distribution of atmospheric moisture, we study an advection-condensation model in which water vapor is passively advected by a prescribed velocity and condensation acts as a sink that maintains the specific humidity below a prescribed, spatially dependent saturation value. The velocity consists of two parts: a single vortex representing large-scale coherent flow (e.g. the Hadley cell) and a white noise component mimicking small-scale turbulence. Steady-state is achieved in the presence of a moisture source at a boundary. We formulate this model as a set of stochastic differential equations. In the fast advection limit, analytical expression for the water vapor distribution is obtained by matched asymptotics. This allows us to make various predictions including the dependence of total precipitation on the vortex strength. These analytical results are verified by Monte Carlo simulations. This work is supported by the UK EPSRC Grant EP/I028072/1 and the Feasibility Fund from the UK EPSRC Network ReCoVER.

  7. Solving turbulent diffusion flame in cylindrical frame applying an improved advective kinetics scheme

    NASA Astrophysics Data System (ADS)

    Darbandi, Masoud; Ghafourizadeh, Majid

    2015-12-01

    In this work, we derive a few new advective flux approximation expressions, apply them in a hybrid finite-volume-element (FVE) formulation, and solve the turbulent reacting flow governing equations in the cylindrical frame. To derive these advective-kinetic-based expressions, we benefit from the advantages of a physical influence scheme (PIS) basically, extend it to the cylindrical frame suitably, and approximate the required advective flux terms at the cell faces more accurately. The present numerical scheme not only respects the physics of flow correctly but also resolves the pressure-velocity coupling problem automatically. We also suggest a bi-implicit algorithm to solve the set of coupled turbulent reacting flow governing equations, in which the turbulence and chemistry governing equations are solved simultaneously. To evaluate the accuracy of new derived FVE-PIS expressions, we compare the current solutions with other available numerical solutions and experimental data. The comparisons show that the new derived expressions provide some more advantages over the past numerical approaches in solving turbulent diffusion flame in the cylindrical frame. Indeed, the current method and formulations can be used to solve and analyze the turbulent diffusion flames in the cylindrical coordinates very reliably.

  8. Universal limiter for transient interpolation modeling of the advective transport equations: The ULTIMATE conservative difference scheme

    NASA Technical Reports Server (NTRS)

    Leonard, B. P.

    1988-01-01

    A fresh approach is taken to the embarrassingly difficult problem of adequately modeling simple pure advection. An explicit conservative control-volume formation makes use of a universal limiter for transient interpolation modeling of the advective transport equations. This ULTIMATE conservative difference scheme is applied to unsteady, one-dimensional scalar pure advection at constant velocity, using three critical test profiles: an isolated sine-squared wave, a discontinuous step, and a semi-ellipse. The goal, of course, is to devise a single robust scheme which achieves sharp monotonic resolution of the step without corrupting the other profiles. The semi-ellipse is particularly challenging because of its combination of sudden and gradual changes in gradient. The ULTIMATE strategy can be applied to explicit conservation schemes of any order of accuracy. Second-order schemes are unsatisfactory, showing steepening and clipping typical of currently popular so-called high resolution shock-capturing of TVD schemes. The ULTIMATE third-order upwind scheme is highly satisfactory for most flows of practical importance. Higher order methods give predictably better step resolution, although even-order schemes generate a (monotonic) waviness in the difficult semi-ellipse simulation. Little is to be gained above ULTIMATE fifth-order upwinding which gives results close to the ultimate for which one might hope.

  9. Anisotropic Turbulent Advection of a Passive Vector Field: Effects of the Finite Correlation Time

    NASA Astrophysics Data System (ADS)

    Antonov, N. V.; Gulitskiy, N. M.

    2016-02-01

    The turbulent passive advection under the environment (velocity) field with finite correlation time is studied. Inertial-range asymptotic behavior of a vector (e.g., magnetic) field, passively advected by a strongly anisotropic turbulent flow, is investigated by means of the field theoretic renormalization group and the operator product expansion. The advecting velocity field is Gaussian, with finite correlation time and prescribed pair correlation function. The inertial-range behavior of the model is described by two regimes (the limits of vanishing or infinite correlation time) that correspond to nontrivial fixed points of the RG equations and depend on the relation between the exponents in the energy energy spectrum ɛ ∝ k⊥1-ξ and the dispersion law ω ∝ k⊥2-η . The corresponding anomalous exponents are associated with the critical dimensions of tensor composite operators built solely of the passive vector field itself. In contrast to the well-known isotropic Kraichnan model, where various correlation functions exhibit anomalous scaling behavior with infinite sets of anomalous exponents, here the dependence on the integral turbulence scale L has a logarithmic behavior: instead of power-like corrections to ordinary scaling, determined by naive (canonical) dimensions, the anomalies manifest themselves as polynomials of logarithms of L. Due to the presence of the anisotropy in the model, all multiloop diagrams are equal to zero, thus this result is exact.

  10. A deterministic Lagrangian particle separation-based method for advective-diffusion problems

    NASA Astrophysics Data System (ADS)

    Wong, Ken T. M.; Lee, Joseph H. W.; Choi, K. W.

    2008-12-01

    A simple and robust Lagrangian particle scheme is proposed to solve the advective-diffusion transport problem. The scheme is based on relative diffusion concepts and simulates diffusion by regulating particle separation. This new approach generates a deterministic result and requires far less number of particles than the random walk method. For the advection process, particles are simply moved according to their velocity. The general scheme is mass conservative and is free from numerical diffusion. It can be applied to a wide variety of advective-diffusion problems, but is particularly suited for ecological and water quality modelling when definition of particle attributes (e.g., cell status for modelling algal blooms or red tides) is a necessity. The basic derivation, numerical stability and practical implementation of the NEighborhood Separation Technique (NEST) are presented. The accuracy of the method is demonstrated through a series of test cases which embrace realistic features of coastal environmental transport problems. Two field application examples on the tidal flushing of a fish farm and the dynamics of vertically migrating marine algae are also presented.

  11. The effects of advection solvers on the performance of air quality models

    SciTech Connect

    Tanrikulu, S.; Odman, M.T.

    1996-12-31

    The available numerical solvers for the advection term in the chemical species conservation equation have different properties, and consequently introduce different types of errors. These errors can affect the performance of air quality models and lead to biases in model results. In this study, a large number of advection solvers have been studied and six of them were identified as having potential for use in photochemical models. The identified solvers were evaluated extensively using various numerical tests that are relevant to air quality simulations. Among the solvers evaluated, three of them showed better performance in terms of accuracy and some other characteristics such as conservation of mass and positivity. They are the solvers by Bott, Yuamartino, and Dabdub and Seinfeld. These three solvers were incorporated into the SARMAP Air Quality Model (SAQM) and the August 3-6, 1990 ozone episode in the San Joaquin Valley of California was simulated with each. A model performance analysis was conducted for each simulation using the rich air quality database of the 1990 San Joaquin Valley Air Quality Study. The results of the simulations were compared with each other and the effects of advection solvers on the performance of the model are discussed.

  12. Computational sciences in the upstream oil and gas industry.

    PubMed

    Halsey, Thomas C

    2016-10-13

    The predominant technical challenge of the upstream oil and gas industry has always been the fundamental uncertainty of the subsurface from which it produces hydrocarbon fluids. The subsurface can be detected remotely by, for example, seismic waves, or it can be penetrated and studied in the extremely limited vicinity of wells. Inevitably, a great deal of uncertainty remains. Computational sciences have been a key avenue to reduce and manage this uncertainty. In this review, we discuss at a relatively non-technical level the current state of three applications of computational sciences in the industry. The first of these is seismic imaging, which is currently being revolutionized by the emergence of full wavefield inversion, enabled by algorithmic advances and petascale computing. The second is reservoir simulation, also being advanced through the use of modern highly parallel computing architectures. Finally, we comment on the role of data analytics in the upstream industry.This article is part of the themed issue 'Energy and the subsurface'. PMID:27597785

  13. Growing 'Alfvenic' modes in the upstream region of Saturn

    NASA Technical Reports Server (NTRS)

    Orlowski, D. S.; Russell, C. T.; Krauss-Varban, D.; Omidi, N.

    1994-01-01

    Recent studies of low-frequency electromagnetic waves upstream of the Saturn bow shock have shown that these waves, in contrast to those at Earth, are observed not in one, but in at least two, distinct frequency bands. The results of wave mode identification based on the Hall-magnetohydrodynamic (MHD) model of plasma and observed wave polarization suggested that these waves propagate in the high beta intermediate mode. However, the underlying instability was not unambiguously determined. In the present paper we use the full electromagnetic dispersion relation derived from linear Vlasov theory in order to examine which of the plasma modes, with observed properties, are unstable in an isotropic Maxwellian plasma in the presence of backstreaming proton beams consistent with Voyager 2 observations at Saturn. As a result we find that the unstable 'Alfvenic' beam mode, as well as resonant and non-resonant fast magnetosonic modes have properties consistent with the data. Moreover, we find that in contrast to the Earth's upstream waves, at Saturn no 'kinetic' normal mode can account for the observed magnetic polarization.

  14. Anomalous transport regimes and asymptotic concentration distributions in the presence of advection and diffusion on a comb structure

    NASA Astrophysics Data System (ADS)

    Dvoretskaya, Olga A.; Kondratenko, Peter S.

    2009-04-01

    We study the transport of impurity particles on a comb structure in the presence of advection. The main body concentration and asymptotic concentration distributions are obtained. Seven different transport regimes occur on the comb structure with finite teeth: classical diffusion, advection, quasidiffusion, subdiffusion, slow classical diffusion, and two kinds of slow advection. Quasidiffusion deserves special attention. It is characterized by a linear growth of the mean-square displacement. However, quasidiffusion is an anomalous transport regime. We established that a change in transport regimes in time leads to a change in regimes in space. Concentration tails have a cascade structure, namely, consisting of several parts.

  15. Three-dimensional numerical modeling of mixing at the junction of the Calumet-Sag Channel and the Chicago Sanitary and Ship Canal: A comparison between density-driven and advection-driven mixing

    USGS Publications Warehouse

    Wang, Dongchen; Dudda, Som; Jackson, P. Ryan; Garcia, Marcelo H.

    2016-01-01

    The Chicago Area Waterway System (CAWS) includes the Chicago Sanitary and Ship Canal (CSSC) and the Calumet-Sag Channel (Cal-Sag), the two primary, man-made connections between the Mississippi River Basin and the Great Lakes. The U.S. Geological Survey (USGS) monitors diversion of Great Lakes water at a streamgage just downstream of the confluence of the CSSC and Cal-Sag (known as Sag Junction). Previous studies have explored the complex hydrodynamics in the CAWS near Sag Junction and at the USGS streamgage near Lemont, Illinois. The current study explores the mixing at Sag Junction which can be purely advection-driven or driven by density differences between the two branches. The current study simulates and analyzes two cases: 1) the density of water in CSSC is greater than in the Cal-Sag, 2) the density of the CSSC water is less than in the Cal-Sag. The density difference between the branches was found to play a major role in influencing the mixing process compared with purely advection-driven mixing. Density differences created near-bed gravity currents, some of which intruded upstream into the CSSC or Cal-Sag creating bi-directional flows. The phenomenon of double plunging was observed, along with formation of a recirculation zone between the two plunging fronts. Local mixing at the confluence was enhanced by density differences between the two channels, but mixing downstream from the confluence was impeded due to formation of a stabilizing stratification.

  16. Stochastic interpretation of the advection-diffusion equation and its relevance to bed load transport

    NASA Astrophysics Data System (ADS)

    Ancey, C.; Bohorquez, P.; Heyman, J.

    2015-12-01

    The advection-diffusion equation is one of the most widespread equations in physics. It arises quite often in the context of sediment transport, e.g., for describing time and space variations in the particle activity (the solid volume of particles in motion per unit streambed area). Phenomenological laws are usually sufficient to derive this equation and interpret its terms. Stochastic models can also be used to derive it, with the significant advantage that they provide information on the statistical properties of particle activity. These models are quite useful when sediment transport exhibits large fluctuations (typically at low transport rates), making the measurement of mean values difficult. Among these stochastic models, the most common approach consists of random walk models. For instance, they have been used to model the random displacement of tracers in rivers. Here we explore an alternative approach, which involves monitoring the evolution of the number of particles moving within an array of cells of finite length. Birth-death Markov processes are well suited to this objective. While the topic has been explored in detail for diffusion-reaction systems, the treatment of advection has received no attention. We therefore look into the possibility of deriving the advection-diffusion equation (with a source term) within the framework of birth-death Markov processes. We show that in the continuum limit (when the cell size becomes vanishingly small), we can derive an advection-diffusion equation for particle activity. Yet while this derivation is formally valid in the continuum limit, it runs into difficulty in practical applications involving cells or meshes of finite length. Indeed, within our stochastic framework, particle advection produces nonlocal effects, which are more or less significant depending on the cell size and particle velocity. Albeit nonlocal, these effects look like (local) diffusion and add to the intrinsic particle diffusion (dispersal due

  17. Advective Removal of Intraparticle Uranium from Contaminated Vadose Zone Sediments, Hanford, USA

    SciTech Connect

    Ilton, Eugene S.; Qafoku, Nikolla; Liu, Chongxuan; Moore, D. A.; Zachara, John M.

    2008-03-01

    A column study on U contaminated vadose zone sediments from the Hanford Site, WA, was performed in order to aid the development of a model for predicting U(VI) release rates under a dynamic flow regime and for variable geochemical conditions. The sediments of interest are adjacent to and below tank BX-102, part of the BX tank farm that contained high level liquid radioactive waste. Two sediments, with different U(VI) loadings and intraparticle large fracture vs. smaller fracture ratios, were reacted with three different solutions. The primary reservoir for U(VI) appears to be a micron-sized nanocrystalline Na-U-Si phase, possibly Na-boltwoodite, that nucleated and grew on plagioclase grains that line fractures within sand-sized granitic clasts. The solutions were all calcite saturated and in equilibrium with atmospheric CO2, where one solution was simply DI-water, the second was a synthetic ground water (SGW) with elevated Na, and the third was the same SGW but with both elevated Na and Si. The latter two solutions were employed, in part, to test the effect of saturation state on U(VI) release. For both sediments and all three electrolytes, there was an initial rapid release of U(VI) to the advecting solution followed by a plateau of low U(VI) concentration. U(VI) effluent concentration increased during subsequent stop flow (SF) events. The electrolytes with elevated Na and Si appreciably depressed U(VI) concentrations relative to DI water. The effluent data for both sediments and all three electrolytes was simulated reasonably well by a three domain model (the advecting fluid, fractures, and matrix) that coupled U(VI) dissolution rates, intraparticle U(VI) diffusion, and interparticle advective transport of U(VI); where key transport and dissolution processes had been parameterized in previous batch studies. For the calcite-saturated DI-water, U(VI) concentrations in the effluent remained far below saturation with respect to Na-boltwoodite and release of U(VI) to

  18. Variability of Sub-Canopy Flow, Temperature, and Horizontal Advection in Moderately Complex Terrain

    NASA Astrophysics Data System (ADS)

    Thomas, Christoph K.

    2011-04-01

    We examine the space-time structure of the wind and temperature fields, as well as that of the resulting spatial temperature gradients and horizontal advection of sensible heat, in the sub-canopy of a forest with a dense overstorey in moderately complex terrain. Data were collected from a sensor network consisting of ten stations and subject to orthogonal decomposition using the multiresolution basis set and stochastic analyses including two-point correlations, dimensional structure functions, and various other bulk measures for space and time variability. Despite some similarities, fundamental differences were found in the space-time structure of the motions dominating the variability of the sub-canopy wind and temperature fields. The dominating motions occupy similar spatial, but different temporal, scales. A conceptual space-time diagram was constructed based on the stochastic analysis that includes the important end members of the spatial and temporal scales of the observed motions of both variables. Short-lived and small-scale motions govern the variability of the wind, while the diurnal temperature oscillation driven by the surface radiative transfer is the main determinant of the variability in the temperature signal, which occupies much larger time scales. This scale mismatch renders Taylor's hypothesis for sub-canopy flow invalid and aggravates the computation of meaningful estimates of horizontal advective fluxes without dense spatial information. It may further explain the ambiguous and inconclusive results reported in numerous energy and mass balance and advection studies evaluating the hypothesis that accounting for budget components other than the change in storage term and the vertical turbulent flux improves the budget closure when turbulent diffusion is suppressed in plant canopies. Estimates of spatial temperature gradients and advective fluxes were sensitive to the network geometry and the spatial interpolation method. The assumption of linear

  19. Supramolecular Control over Split-Luciferase Complementation.

    PubMed

    Bosmans, Ralph P G; Briels, Jeroen M; Milroy, Lech-Gustav; de Greef, Tom F A; Merkx, Maarten; Brunsveld, Luc

    2016-07-25

    Supramolecular split-enzyme complementation restores enzymatic activity and allows for on-off switching. Split-luciferase fragment pairs were provided with an N-terminal FGG sequence and screened for complementation through host-guest binding to cucurbit[8]uril (Q8). Split-luciferase heterocomplex formation was induced in a Q8 concentration dependent manner, resulting in a 20-fold upregulation of luciferase activity. Supramolecular split-luciferase complementation was fully reversible, as revealed by using two types of Q8 inhibitors. Competition studies with the weak-binding FGG peptide revealed a 300-fold enhanced stability for the formation of the ternary heterocomplex compared to binding of two of the same fragments to Q8. Stochiometric binding by the potent inhibitor memantine could be used for repeated cycling of luciferase activation and deactivation in conjunction with Q8, providing a versatile module for in vitro supramolecular signaling networks. PMID:27356091

  20. Small-molecule-dependent split aptamer ligation.

    PubMed

    Sharma, Ashwani K; Heemstra, Jennifer M

    2011-08-17

    Here we describe the first use of small-molecule binding to direct a chemical reaction between two nucleic acid strands. The reported reaction is a ligation between two fragments of a DNA split aptamer using strain-promoted azide-alkyne cycloaddition. Utilizing the split aptamer for cocaine, we demonstrate small-molecule-dependent ligation that is dose-dependent over a wide range of cocaine concentrations and is compatible with complex biological fluids such as human blood serum. Moreover, studies of split aptamer ligation at varying salt concentrations and using structurally similar analogues of cocaine have revealed new insight into the assembly and small-molecule binding properties of the cocaine split aptamer. The ability to translate the presence of a small-molecule target into the output of DNA ligation is anticipated to enable the development of new, broadly applicable small-molecule detection assays. PMID:21761903

  1. Divided Opinions on the Split Fovea

    ERIC Educational Resources Information Center

    Ellis, Andrew W.; Brysbaert, Marc

    2010-01-01

    We explain once again the distinction between the "split fovea theory" and the "bilateral projection theory", and consider the implications of the two theories for understanding the processing of centrally fixated words and faces.

  2. Solar activity and oscillation frequency splittings

    NASA Technical Reports Server (NTRS)

    Woodard, M. F.; Libbrecht, K. G.

    1993-01-01

    Solar p-mode frequency splittings, parameterized by the coefficients through order N = 12 of a Legendre polynomial expansion of the mode frequencies as a function of m/L, were obtained from an analysis of helioseismology data taken at Big Bear Solar Observatory during the 4 years 1986 and 1988-1990 (approximately solar minimum to maximum). Inversion of the even-index splitting coefficients confirms that there is a significant contribution to the frequency splittings originating near the solar poles. The strength of the polar contribution is anti correlated with the overall level or solar activity in the active latitudes, suggesting a relation to polar faculae. From an analysis of the odd-index splitting coefficients we infer an uppor limit to changes in the solar equatorial near-surface rotatinal velocity of less than 1.9 m/s (3 sigma limit) between solar minimum and maximum.

  3. Structural basis of photosynthetic water-splitting

    SciTech Connect

    Shen, Jian-Ren; Kawakami, Keisuke; Kamiya, Nobuo

    2013-12-10

    Photosynthetic water-splitting takes place in photosystem II (PSII), a membrane protein complex consisting of 20 subunits with an overall molecular mass of 350 kDa. The light-induced water-splitting reaction catalyzed by PSII not only converts light energy into biologically useful chemical energy, but also provides us with oxygen indispensible for sustaining oxygenic life on the earth. We have solved the structure of PSII at a 1.9 Å resolution, from which, the detailed structure of the Mn{sub 4}CaO{sub 5}-cluster, the catalytic center for water-splitting, became clear. Based on the structure of PSII at the atomic resolution, possible mechanism of light-induced water-splitting was discussed.

  4. Antenna Splitting Functions for Massive Particles

    SciTech Connect

    Larkoski, Andrew J.; Peskin, Michael E.; /SLAC

    2011-06-22

    An antenna shower is a parton shower in which the basic move is a color-coherent 2 {yields} 3 parton splitting process. In this paper, we give compact forms for the spin-dependent antenna splitting functions involving massive partons of spin 0 and spin 1/2. We hope that this formalism we have presented will be useful in describing the QCD dynamics of the top quark and other heavy particles at LHC.

  5. Spin-dependent antenna splitting functions

    SciTech Connect

    Larkoski, Andrew J.; Peskin, Michael E.

    2010-03-01

    We consider parton showers based on radiation from QCD dipoles or 'antennas'. These showers are built from 2{yields}3 parton splitting processes. The question then arises of what functions replace the Altarelli-Parisi splitting functions in this approach. We give a detailed answer to this question, applicable to antenna showers in which partons carry definite helicity, and to both initial- and final-state emissions.

  6. Spontaneous splitting of a quadruply charged vortex.

    PubMed

    Isoshima, T; Okano, M; Yasuda, H; Kasa, K; Huhtamäki, J A M; Kumakura, M; Takahashi, Y

    2007-11-16

    We studied the splitting instability of a quadruply charged vortex both experimentally and theoretically. The density defect, which is a signature of the vortex core, is experimentally observed to deform into a linear shape. The deformed defect is theoretically confirmed to be an array of four linearly aligned singly charged vortices. The array of vortices rotates and precesses simultaneously with different angular velocities. The initial state of the system is not rotationally symmetric, which enables spontaneous splitting without external perturbations. PMID:18233124

  7. Spontaneous Splitting of a Quadruply Charged Vortex

    SciTech Connect

    Isoshima, T.; Okano, M.; Yasuda, H.; Kasa, K.; Huhtamaeki, J. A. M.; Kumakura, M.; Takahashi, Y.

    2007-11-16

    We studied the splitting instability of a quadruply charged vortex both experimentally and theoretically. The density defect, which is a signature of the vortex core, is experimentally observed to deform into a linear shape. The deformed defect is theoretically confirmed to be an array of four linearly aligned singly charged vortices. The array of vortices rotates and precesses simultaneously with different angular velocities. The initial state of the system is not rotationally symmetric, which enables spontaneous splitting without external perturbations.

  8. Smallness of baryon asymmetry from split supersymmetry

    SciTech Connect

    Kasuya, Shinta; Takahashi, Fuminobu

    2005-06-15

    The smallness of the baryon asymmetry in our universe is one of the greatest mysteries and may originate from some profound physics beyond the standard model. We investigate the Affleck-Dine baryogenesis in split supersymmetry, and find that the smallness of the baryon asymmetry is directly related to the hierarchy between the supersymmetry breaking squark/slepton masses and the weak scale. Put simply, the baryon asymmetry is small because of the split mass spectrum.

  9. Laser beam splitting by polarization encoding.

    PubMed

    Wan, Chenhao

    2015-03-20

    A scheme is proposed to design a polarization grating that splits an incident linearly polarized beam to an array of linearly polarized beams of identical intensity distribution and various azimuth angles of linear polarization. The grating is equivalent to a wave plate with space-variant azimuth angle and space-variant phase retardation. The linear polarization states of all split beams make the grating suitable for coherent beam combining architectures based on Dammann gratings. PMID:25968540

  10. Intersectional Gene Expression in Zebrafish Using the Split KalTA4 System

    PubMed Central

    2015-01-01

    Abstract In this study, we describe the adaptation of the split Gal4 system for zebrafish. The Gal4-UAS system is widely used for expression of genes-of-interest by crossing driver lines expressing the transcription factor Gal4 (under the control of the promoter of interest) with reporter lines where upstream activating sequence (UAS) repeats (recognized by Gal4) drive expression of the genes-of-interest. In the Split Gal4 system, hemi-drivers separately encode the DNA-binding domain (DBD) and the activation domain (AD) of Gal4. When encoded under two different promoters, only those cells in the intersection of the promoters' expression pattern and in which both promoters are active reconstitute a functional Gal4 and activate expression from a UAS-driven transgene. We split the zebrafish-optimized version of Gal4, KalTA4, and generated a hemi-driver encoding the KalTA4 DBD and a hemi-driver encoding KalTA4's AD. We show that split KalTA4 domains can assemble in vivo and transactivate a UAS reporter transgene and that each hemi-driver alone cannot transactivate the reporter. Also, transactivation can happen in several cell types, with similar efficiency to intact KalTA4. Finally, in transient mosaic expression assays, we show that when hemi-drivers are preceded by two distinct promoters, they restrict the expression of an UAS-driven reporter from a broader pattern (sox10) to its constituent smaller neuronal pattern. The Split KalTA4 system should be useful for expression of genes-of-interest in an intersectional manner, allowing for more refined manipulations of cell populations in zebrafish. PMID:26485616

  11. THE INTERPLAY BETWEEN GEOCHEMICAL REACTIONS AND ADVECTION-DISPERSION IN CONTAMINANT TRANSPORT AT A URANIUM MILL TAILINGS SITE

    EPA Science Inventory

    It is well known that the fate and transport of contaminants in the subsurface are controlled by complex processes including advection, dispersion-diffusion, and chemical reactions. However, the interplay between the physical transport processes and chemical reactions, and their...

  12. Replacement of split-pin assemblies in nuclear reactors

    SciTech Connect

    Nee, J.D.; Green, R.A.

    1989-12-12

    This patent describes a pin-insertion/torque tool for the replacement of old split-pin assemblies. Each of the new split-pin assemblies including a new split-pin having times and a new nut for securing the new split pin in the guide tube, a new nut being inserted in the guide tube in position to receive a split pin. The the pin-insertion/torque tool including a blade means for engaging a new split pin with the blade with the tines of the new split pins straddling the blade, means, connected to the blade, for advancing the split-pin into the guide tube into threading engagement with the new nut positioned to receive a new split pin and means, to be connected to the nut for securing the new nut onto the new split pin while the split pin is engaged by the blade.

  13. Quintessence and phantom emerging from the split-complex field and the split-quaternion field

    NASA Astrophysics Data System (ADS)

    Gao, Changjun; Chen, Xuelei; Shen, You-Gen

    2016-01-01

    Motivated by the mathematic theory of split-complex numbers (or hyperbolic numbers, also perplex numbers) and the split-quaternion numbers (or coquaternion numbers), we define the notion of split-complex scalar field and the split-quaternion scalar field. Then we explore the cosmic evolution of these scalar fields in the background of spatially flat Friedmann-Robertson-Walker Universe. We find that both the quintessence field and the phantom field could naturally emerge in these scalar fields. Introducing the metric of field space, these theories fall into a subclass of the multi-field theories which have been extensively studied in inflationary cosmology.

  14. Comparison of Results for Quarter 1 Surface Water Split Samples Collected at the Nuclear Fuel Services Site, Erwin, Tennessee

    SciTech Connect

    David A. King, CHP, PMP

    2012-10-10

    Oak Ridge Associated Universities (ORAU), under the Oak Ridge Institute for Science and Education (ORISE) contract, collected split surface water samples with Nuclear Fuel Services (NFS) representatives on August 22, 2012. Representatives from the U.S. Nuclear Regulatory Commission and Tennessee Department of Environment and Conservation were also in attendance. Samples were collected at four surface water stations, as required in the approved Request for Technical Assistance number 11-018. These stations included Nolichucky River upstream (NRU), Nolichucky River downstream (NRD), Martin Creek upstream (MCU), and Martin Creek downstream (MCD). Both ORAU and NFS performed gross alpha and gross beta analyses. The comparison of results using the duplicate error ratio (DER), also known as the normalized absolute difference. A DER ≤ 3 indicates that, at a 99% confidence interval, split sample results do not differ significantly when compared to their respective one standard deviation (sigma) uncertainty. The NFS split sample report does not specify the confidence level of reported uncertainties. Therefore, standard two sigma reporting is assumed and uncertainty values were divided by 1.96. A comparison of split sample results, using the DER equation, indicates one set with a DER greater than 3. A DER of 3.1 is calculated for gross alpha results from ORAU sample 5198W0003 and NFS sample MCU-310212003. The ORAU result is 0.98 ± 0.30 pCi/L (value ± 2 sigma) compared to the NFS result of -0.08 ± 0.60 pCi/L. Relatively high DER values are not unexpected for low (e.g., background) analyte concentrations analyzed by separate laboratories, as is the case here. It is noted, however, NFS uncertainties are at least twice the ORAU uncertainties, which contributes to the elevated DER value. Differences in ORAU and NFS minimum detectable activities are even more pronounced. comparison of ORAU and NFS split samples produces reasonably consistent results for low (e.g., background

  15. Solar wind flow upstream of the coronal slow shock

    NASA Technical Reports Server (NTRS)

    Whang, Y. C.

    1986-01-01

    Slow shocks have been predicted to exist embedded in large coronal holes at low altitude. Two or more curved slow shocks may link together to form a composite discontinuity surface around the sun which may be called the coronal slow shock (CSS). Here a solar-wind model is studied under the assumption that a standing CSS exists and cororates with the sun at a constant angular velocity. A steady, axisymmetrical one-fluid model is introduced to study the expansion of solar wind in the open-field region upstream of the CSS. The model requires that the conditions downstream of the CSS near the equatorial plane can produce a solar wind agreeable with the observations made near the earth's orbit. The paper presents an illustrative calculation in which the polar caps within 60 deg of the polar angle are assumed to be the source region of the solar wind.

  16. Shape and shear guide sperm cells spiraling upstream

    NASA Astrophysics Data System (ADS)

    Kantsler, Vasily; Dunkel, Jorn; Goldstein, Raymond E.

    2014-11-01

    A major puzzle in biology is how mammalian sperm determine and maintain the correct swimming direction during the various phases of the sexual reproduction process. Currently debated mechanisms for sperm long range travel vary from peristaltic pumping to temperature sensing (thermotaxis) and direct response to fluid flow (rheotaxis), but little is known quantitatively about their relative importance. Here, we report the first quantitative experimental study of mammalian sperm rheotaxis. Using microfluidic devices, we investigate systematically the swimming behavior of human and bull sperm over a wide range of physiologically relevant shear rates and viscosities. Our measurements show that the interplay of fluid shear, steric surface-interactions and chirality of the flagellar beat leads to a stable upstream spiraling motion of sperm cells, thus providing a generic and robust rectification mechanism to support mammalian fertilization. To rationalize these findings, we identify a minimal mathematical model that is capable of describing quantitatively the experimental observations.

  17. Upstream solutions for price-gouging on critical generic medicines.

    PubMed

    Houston, Adam R; Beall, Reed F; Attaran, Amir

    2016-01-01

    Exorbitant price increases for critical off-patent medicines have received considerable media attention in recent months, leading to an investigation by the U.S. Senate. However, much of this attention has focused upon the companies that initiated the price increases, all of whom had recently acquired the drugs in question. Overlooked are upstream interventions with the originators of these drugs to prevent generics trolling in the first place. Using the particular example of Eli Lilly and Company's efforts to divest itself of cycloserine, a flawed process that paved the way for the recent price hike by Rodelis Therapeutics, this article highlights the responsibilities of drug originators, and safeguards to ensure similar rights transfers do not affect ongoing affordable access. PMID:27141308

  18. Upstream and downstream strategies to economize biodiesel production.

    PubMed

    Hasheminejad, Meisam; Tabatabaei, Meisam; Mansourpanah, Yaghoub; Khatami far, Mahdi; Javani, Azita

    2011-01-01

    In recent years biodiesel has drawn considerable amount of attention as a clean and renewable fuel. Biodiesel is produced from renewable sources such as vegetable oils and animal fat mainly through catalytic or non-catalytic transesterification method as well as supercritical method. However, as a consequence of disadvantages of these methods, the production cost increases dramatically. This article summarizes different biodiesel production methods with a focus on their advantages and disadvantages. The downstream and upstream strategies such as using waste cooking oils, application of non-edible plant oils, plant genetic engineering, using membrane separation technology for biodiesel production, separation and purification, application of crude glycerin as an energy supplement for ruminants, glycerin ultra-purification and their consequent roles in economizing the production process are fully discussed in this article. PMID:20974530

  19. From worker health to citizen health: moving upstream.

    PubMed

    Sepulveda, Martin-Jose

    2013-12-01

    New rapid growth economies, urbanization, health systems crises, and "big data" are causing fundamental changes in social structures and systems, including health. These forces for change have significant consequences for occupational and environmental medicine and will challenge the specialty to think beyond workers and workplaces as the principal locus of innovation for health and performance. These trends are placing great emphasis on upstream strategies for addressing the complex systems dynamics of the social determinants of health. The need to engage systems in communities for healthier workforces is a shift in orientation from worker and workplace centric to citizen and community centric. This change for occupational and environmental medicine requires extending systems approaches in the workplace to communities that are systems of systems and that require different skills, data, tools, and partnerships. PMID:24284749

  20. 5. Looking west upstream, towards the location of the erstwhile ...

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

    5. Looking west upstream, towards the location of the erstwhile intake flume into canal from the upper reaches of the Potomac River above the Great Falls, on the old Potowmack Canal built by George Washington. The plan contemplated canal navigation around the Great Falls of the Potomac River, located on the Virginia side of the Potomac, about 15 miles above Washington, D.C. The Company was organized in 1785, and by 1802, this and three or four smaller canals were substantially completed and raft-like boats began operation with materials from the west to the city of Georgetown. 'Although the canals and locks of the Potomac Canal were considered a great engineering accomplishment, the improvements to the river channel were inadequate. Disappointment ... - Potowmack Company: Great Falls Canal & Locks, Great Falls, Fairfax County, VA