WorldWideScience

Sample records for stagnation streamline flow

  1. On Stagnation points and streamline topology in vortex flows

    DEFF Research Database (Denmark)

    Aref, Hassan; Brøns, Morten

    1997-01-01

    The problem of locating stagnation points in the flow produced by a system of N interacting point vortices in two dimensions is considered. The general solution, which follows from an 1864 theorem by Siebeck, that the stagnation points are the foci of a certain plane curve of class N-1 that has a...

  2. On stagnation points and streamline topology in vortex flows

    DEFF Research Database (Denmark)

    Aref, Hassan; Brøns, Morten

    1998-01-01

    The problem of locating stagnation points in the flow produced by a system of N vortices in two dimensions is considered. The general solution follows from a 1864 theorem by Siebeck, that the stagnation points are the foci of a certain plane curve of class N-1 that has all lines connecting vortic...

  3. Inertioelastic Flow Instability at a Stagnation Point

    Science.gov (United States)

    Burshtein, Noa; Zografos, Konstantinos; Shen, Amy Q.; Poole, Robert J.; Haward, Simon J.

    2017-10-01

    A number of important industrial applications exploit the ability of small quantities of high molecular weight polymer to suppress instabilities that arise in the equivalent flow of Newtonian fluids, a particular example being turbulent drag reduction. However, it can be extremely difficult to probe exactly how the polymer acts to, e.g., modify the streamwise near-wall eddies in a fully turbulent flow. Using a novel cross-slot flow configuration, we exploit a flow instability in order to create and study a single steady-state streamwise vortex. By quantitative experiment, we show how the addition of small quantities (parts per million) of a flexible polymer to a Newtonian solvent dramatically affects both the onset conditions for this instability and the subsequent growth of the axial vorticity. Complementary numerical simulations with a finitely extensible nonlinear elastic dumbbell model show that these modifications are due to the growth of polymeric stress within specific regions of the flow domain. Our data fill a significant gap in the literature between the previously reported purely inertial and purely elastic flow regimes and provide a link between the two by showing how the instability mode is transformed as the fluid elasticity is varied. Our results and novel methods are relevant to understanding the mechanisms underlying industrial uses of weakly elastic fluids and also to understanding inertioelastic instabilities in more confined flows through channels with intersections and stagnation points.

  4. Streamline topology of axisymmetric flows

    DEFF Research Database (Denmark)

    Brøns, Morten

    Topological fluid mechanics in the sense of the present paper is the study and classification of flow patterns close to a critical point. Here we discuss the topology of steady viscous incompressible axisymmetric flows in the vicinity of the axis. Following previous studies the velocity field $v...... to the authors knowledge has not been used systematically to high orders in topological fluid mechanics. We compare the general results with experimental and computational results on the Vogel-Ronneberg flow. We show that the topology changes observed when recirculating bubbles on the vortex axis are created...... and interact follow the topological classification and that the complete set of patterns found is contained in a codimension-4 unfolding of the most simple singular configuration....

  5. Estimation of Centers and Stagnation points in optical flow fields

    DEFF Research Database (Denmark)

    Larsen, Rasmus

    1997-01-01

    In a topological sense fluid flows are characterised by their stagnation points. Given a temporal sequence of images of fluids we will consider the application of local polynomials to the estimation of smooth fluid flow fields. The normal flow at intensity contours is estimated from the local dis...

  6. Modeling study of rarefied gas effects on hypersonic reacting stagnation flows

    Science.gov (United States)

    Wang, Zhihui; Bao, Lin

    2014-12-01

    Recent development of the near space hypersonic sharp leading vehicles has raised a necessity to fast and accurately predict the aeroheating in hypersonic rarefied flows, which challenges our understanding of the aerothermodynamics and aerothermochemistry. The present flow and heat transfer problem involves complex rarefied gas effects and nonequilibrium real gas effects which are beyond the scope of the traditional prediction theory based on the continuum hypothesis and equilibrium assumption. As a typical example, it has been found that the classical Fay-Riddell equation fails to predict the stagnation point heat flux, when the flow is either rarefied or chemical nonequilibrium. In order to design a more general theory covering the rarefied reacting flow cases, an intuitive model is proposed in this paper to describe the nonequilibrium dissociation-recombination flow along the stagnation streamline towards a slightly blunted nose in hypersonic rarefied flows. Some characteristic flow parameters are introduced, and based on these parameters, an explicitly analytical bridging function is established to correct the traditional theory to accurately predict the actual aeroheating performance. It is shown that for a small size nose in medium density flows, the flow at the outer edge of the stagnation point boundary layer could be highly nonequilibrium, and the aeroheating performance is distinguished from that of the big blunt body reentry flows at high altitudes. As a result, when the rarefied gas effects and the nonequilibrium real gas effects are both significant, the classical similarity law could be questionable, and it is inadequate to directly analogize results from the classical blunt body reentry problems to the present new generation sharp-leading vehicles. In addition, the direct simulation Monte Carlo method is also employed to validate the conclusion.

  7. Unsteady MHD stagnation flow over a moving wall

    International Nuclear Information System (INIS)

    Kumari, M.; Nath, G.

    2006-01-01

    The unsteady viscous stagnation flow of an electrically conducting fluid over a continuously moving wall with an applied magnetic field has been investigated when the free stream and wall velocities increase arbitrarily with time. The flow is initially (t = 0) steady and at time t > 0, it becomes unsteady. The semi-similar solution of the unsteady Navier-Stokes equations along with the energy equation governing the flow and heat transfer has been obtained numerically. Also the self-similar solution is obtained when the surface and free stream velocities vary inversely as a linear function of time. The shear stress and the heat transfer increase with time and magnetic field. The surface shear stress vanishes for certain value of the ratio of the wall velocity to the free stream velocity. (author)

  8. On the freestream matching condition for stagnation point turbulent flows

    Science.gov (United States)

    Speziale, C. G.

    1989-01-01

    The problem of plane stagnation point flow with freestream turbulence is examined from a basic theoretical standpoint. It is argued that the singularity which arises from the standard kappa-epsilon model is not due to a defect in the model but results from the use of an inconsistent freestream boundary condition. The inconsistency lies in the implementation of a production equals dissipation equilibrium hypothesis in conjunction with a freestream mean velocity field that corresponds to homogeneous plane strain - a turbulent flow which does not reach such a simple equilibrium. Consequently, the adjustment that has been made in the constants of the epsilon-transport equation to eliminate this singularity is not self-consistent since it is tantamount to artificially imposing an equilibrium structure on a turbulent flow which is known not to have one.

  9. Turbulence modeling and surface heat transfer in a stagnation flow region

    Science.gov (United States)

    Wang, C. R.; Yeh, F. C.

    1987-01-01

    Analysis for the turbulent flow field and the effect of freestream turbulence on the surface heat transfer rate of a stagnation flow is presented. The emphasis is on modeling and its augmentation of surface heat transfer rate. The flow field considered is the region near the forward stagnation point of a circular cylinder in a uniform turbulent mean flow.

  10. Mass flow rate measurements in two-phase mixtrues with stagnation probes

    International Nuclear Information System (INIS)

    Fincke, J.R.; Deason, V.A.

    1979-01-01

    Applications of stagnation probes to the measurement of mass flow rate in two-phase flows are discussed. Descriptions of several stagnation devices, which have been evaluated at the Idaho National Engineering Laboratory, are presented along with modeling techniques and two-phase flow data

  11. Nested separatrices in simple shear flows: the effect of localized disturbances on stagnation lines

    OpenAIRE

    Wilson, M.C.T.; Gaskell, P.H.; Savage, M.D.

    2005-01-01

    The effects of localized two-dimensional disturbances on the structure of shear flows featuring a stagnation line are investigated. A simple superposition of a planar Couette flow and Moffatt's [J. Fluid Mech. 18, 1--18 (1964)] streamfunction for the decay of a disturbance between infinite stationary parallel plates shows that in general the stagnation line is replaced by a chain of alternating elliptic and hyperbolic stagnation points with a separation equal to 2.78 times the half-gap betwee...

  12. Streamline topology: Patterns in fluid flows and their bifurcations

    DEFF Research Database (Denmark)

    Brøns, Morten

    2007-01-01

    Using dynamical systems theory, we consider structures such as vortices and separation in the streamline patterns of fluid flows. Bifurcation of patterns under variation of external parameters is studied using simplifying normal form transformations. Flows away from boundaries, flows close to fix...... walls, and axisymmetric flows are analyzed in detail. We show how to apply the ideas from the theory to analyze numerical simulations of the vortex breakdown in a closed cylindrical container....

  13. Topology of streamlines and vorticity contours for two - dimensional flows

    DEFF Research Database (Denmark)

    Andersen, Morten

    on the vortex filament by the localised induction approximation the stream function is slightly modified and an extra parameter is introduced. In this setting two new flow topologies arise, but not more than two critical points occur for any combination of the parameters. The analysis of the closed form show...... by a point vortex above a wall in inviscid fluid. There is no reason to a priori expect equivalent results of the three vortex definitions. However, the study is mainly motivated by the findings of Kudela & Malecha (Fluid Dyn. Res. 41, 2009) who find good agreement between the vorticity and streamlines...

  14. Linear stability analysis of laminar flow near a stagnation point in the slip flow regime

    Science.gov (United States)

    Essaghir, E.; Oubarra, A.; Lahjomri, J.

    2017-12-01

    The aim of the present contribution is to analyze the effect of slip parameter on the stability of a laminar incompressible flow near a stagnation point in the slip flow regime. The analysis is based on the traditional normal mode approach and assumes parallel flow approximation. The Orr-Sommerfeld equation that governs the infinitesimal disturbance of stream function imposed to the steady main flow, which is an exact solution of the Navier-Stokes equation satisfying slip boundary conditions, is obtained by using the powerful spectral Chebyshev collocation method. The results of the effect of slip parameter K on the hydrodynamic characteristics of the base flow, namely the velocity profile, the shear stress profile, the boundary layer, displacement and momentum thicknesses are illustrated and discussed. The numerical data for these characteristics, as well as those of the eigenvalues and the corresponding wave numbers recover the results of the special case of no-slip boundary conditions. They are found to be in good agreement with previous numerical calculations. The effects of slip parameter on the neutral curves of stability, for two-dimensional disturbances in the Reynolds-wave number plane, are then obtained for the first time in the slip flow regime for stagnation point flow. Furthermore, the evolution of the critical Reynolds number against the slip parameter is established. The results show that the critical Reynolds number for instability is significantly increased with the slip parameter and the flow turn out to be more stable when the effect of rarefaction becomes important.

  15. Study of streamline flow in the portal system

    International Nuclear Information System (INIS)

    Atkins, H.L.; Deitch, J.S.; Oster, Z.H.; Perkes, E.A.

    1985-01-01

    The study was undertaken to determine if streamline flow occurs in the portal vein, thus separating inflow from the superior mesenteric artery (SMA) and the inferior mesenteric artery. Previously published data on this subject is inconsistent. Patients undergoing abdominal angiography received two administrations of Tc-99m sulfur colloid, first via the SMA during angiography and, after completion of the angiographic procedure, via a peripheral vein (IV). Anterior images of the liver were recorded over a three minute acquisition before and after the IV injection without moving the patient. The image from the SMA injection was subtracted from the SMA and IV image to provide a pure IV image. Analysis of R to L ratios for selected regions of interest as well as whole lobes was carried out and the shift of R to L (SMA to IV) determined. Six patients had liver metastases from the colon, four had cirrhosis and four had no known liver disease. The shift in the ratio was highly variable without a consistent pattern. Large changes in some patients could be attributed to hepatic artery flow directed to metastases. No consistent evidence for streamlining of portal flow was discerned

  16. Void fraction distribution in a heated rod bundle under flow stagnation conditions

    Energy Technology Data Exchange (ETDEWEB)

    Herrero, V.A.; Guido-Lavalle, G.; Clausse, A. [Centro Atomico Bariloche and Instituto Balseiro, Bariloche (Argentina)

    1995-09-01

    An experimental study was performed to determine the axial void fraction distribution along a heated rod bundle under flow stagnation conditions. The development of the flow pattern was investigated for different heat flow rates. It was found that in general the void fraction is overestimated by the Zuber & Findlay model while the Chexal-Lellouche correlation produces a better prediction.

  17. Effect of bed configuration on pebble flow uniformity and stagnation in the pebble bed reactor

    International Nuclear Information System (INIS)

    Gui, Nan; Yang, Xingtuan; Tu, Jiyuan; Jiang, Shengyao

    2014-01-01

    Highlights: • Pebble flow uniformity and stagnation characteristics are very important for HTR-PM. • Arc- and brachistochrone-shaped configuration effects are studied by DEM simulation. • Best bed configurations with uniform flow and no stagnated pebbles are suggested. • Detailed quantified characteristics of bed configuration effects are shown for explanation. - Abstract: Pebble flow uniformity and stagnation characteristics are very important for the design of pebble bed high temperature gas-cooled reactor. Pebble flows inside some specifically designed contraction configurations of pebble bed are studied by discrete element method. The results show the characteristics of stagnation rates, recycling rates, radial distribution of pebble velocity and residence time. It is demonstrated clearly that the bed with a brachistochrone-shaped configuration achieves optimum levels of flow uniformity and recycling rate concentration, and almost no pebbles are stagnated in the bed. Moreover, the optimum choice among the arc-shaped bed configurations is demonstrated too. Detailed information shows the quantified characteristics of bed configuration effects on flow uniformity. In addition, a good design of the pebble bed configuration is suggested

  18. Dynamic and Stagnating Plasma Flow Leading to Magnetic-Flux-Tube Collimation

    International Nuclear Information System (INIS)

    You, S.; Yun, G.S.; Bellan, P.M.

    2005-01-01

    Highly collimated, plasma-filled magnetic-flux tubes are frequently observed on galactic, stellar, and laboratory scales. We propose that a single, universal magnetohydrodynamic pumping process explains why such collimated, plasma-filled magnetic-flux tubes are ubiquitous. Experimental evidence from carefully diagnosed laboratory simulations of astrophysical jets confirms this assertion and is reported here. The magnetohydrodynamic process pumps plasma into a magnetic-flux tube and the stagnation of the resulting flow causes this flux tube to become collimated

  19. On two special values of temperature factor in hypersonic flow stagnation point

    Science.gov (United States)

    Bilchenko, G. G.; Bilchenko, N. G.

    2018-03-01

    The hypersonic aircraft permeable cylindrical and spherical surfaces laminar boundary layer heat and mass transfer control mathematical model properties are investigated. The nonlinear algebraic equations systems are obtained for two special values of temperature factor in the hypersonic flow stagnation point. The mappings bijectivity between heat and mass transfer local parameters and controls is established. The computation experiments results are presented: the domains of allowed values “heat-friction” are obtained.

  20. Sealable stagnation flow geometries for the uniform deposition of materials and heat

    Science.gov (United States)

    McCarty, Kevin F.; Kee, Robert J.; Lutz, Andrew E.; Meeks, Ellen

    2001-01-01

    The present invention employs a constrained stagnation flow geometry apparatus to achieve the uniform deposition of materials or heat. The present invention maximizes uniform fluxes of reactant gases to flat surfaces while minimizing the use of reagents and finite dimension edge effects. This results, among other things, in large area continuous films that are uniform in thickness, composition and structure which is important in chemical vapor deposition processes such as would be used for the fabrication of semiconductors.

  1. Application of turbulence modeling to predict surface heat transfer in stagnation flow region of circular cylinder

    Science.gov (United States)

    Wang, Chi R.; Yeh, Frederick C.

    1987-01-01

    A theoretical analysis and numerical calculations for the turbulent flow field and for the effect of free-stream turbulence on the surface heat transfer rate of a stagnation flow are presented. The emphasis is on the modeling of turbulence and its augmentation of surface heat transfer rate. The flow field considered is the region near the forward stagnation point of a circular cylinder in a uniform turbulent mean flow. The free stream is steady and incompressible with a Reynolds number of the order of 10 to the 5th power and turbulence intensity of less than 5 percent. For this analysis, the flow field is divided into three regions: (1) a uniform free-stream region where the turbulence is homogeneous and isotropic; (2) an external viscid flow region where the turbulence is distorted by the variation of the mean flow velocity; and, (3) an anisotropic turbulent boundary layer region over the cylinder surface. The turbulence modeling techniques used are the kappa-epsilon two-equation model in the external flow region and the time-averaged turbulence transport equation in the boundary layer region. The turbulence double correlations, the mean velocity, and the mean temperature within the boundary layer are solved numerically from the transport equations. The surface heat transfer rate is calculated as functions of the free-stream turbulence longitudinal microlength scale, the turbulence intensity, and the Reynolds number.

  2. Studies on scaling of flow noise received at the stagnation point of an axisymmetric body

    Science.gov (United States)

    Arakeri, V. H.; Satyanarayana, S. G.; Mani, K.; Sharma, S. D.

    1991-05-01

    A description of the studies related to the problem of scaling of flow noise received at the stagnation point of axisymmetric bodies is provided. The source of flow noise under consideration is the transitional/turbulent regions of the boundary layer flow on the axisymmetric body. Lauchle has recently shown that the noise measured in the laminar region (including the stagnation point) corresponds closely to the noise measured in the transition region, provided that the acoustic losses due to diffraction are accounted for. The present study includes experimental measurement of flow noise at the stagnation point of three different shaped axisymmetric headforms. One of the body shapes chosen is that used by Lauchle in similar studies. This was done to establish the effect of body size on flow noise. The results of the experimental investigations clearly show that the flow noise received at the stagnation point is a strong function of free stream velocity, a moderately strong function of body scale but a weak function of boundary layer thickness. In addition, there is evidence that when body scale change is involved, flow noise amplitude scales but no frequency shift is involved. A scaling procedure is proposed based on the present observations along with those of Lauchle. At a given frequency, the amplitude of noise level obtained under model testing conditions is first scaled to account for differences in the velocity and size corresponding to the prototype conditions; then a correction to this is applied to account for losses due to diffraction, which are estimated on the basis of the geometric theory of diffraction (GTD) with the source being located at the predicted position of turbulent transition. Use of the proposed scaling law to extrapolate presently obtained noise levels to two other conditions involving larger-scale bodies show good agreement with actually measured levels, in particular at higher frequencies. Since model scale results have been used

  3. On the Analytical Solution of Non-Orthogonal Stagnation Point Flow towards a Stretching Sheet

    DEFF Research Database (Denmark)

    Kimiaeifar, Amin; Bagheri, G. H.; Barari, Amin

    2011-01-01

    An analytical solution for non-orthogonal stagnation point for the steady flow of a viscous and incompressible fluid is presented. The governing nonlinear partial differential equations for the flow field are reduced to ordinary differential equations by using similarity transformations existed...... in the literature and are solved analytically by means of the Homotopy Analysis Method (HAM). The comparison of results from this paper and those published in the literature confirms the precise accuracy of the HAM. The resulting analytical equation from HAM is valid for entire physical domain and effective...

  4. Detection of flow separation and stagnation points using artificial hair sensors

    International Nuclear Information System (INIS)

    Phillips, D M; Baur, J W; Ray, C W; Hagen, B J; Reich, G W; Su, W

    2015-01-01

    Recent interest in fly-by-feel approaches for aircraft control has motivated the development of novel sensors for use in aerial systems. Artificial hair sensors (AHSs) are one type of device that promise to fill a unique niche in the sensory suite for aerial systems. In this work, we investigate the capability of an AHS based on structural glass fibers to directly identify flow stagnation and separation points on a cylindrical domain in a steady flow. The glass fibers are functionalized with a radially aligned carbon nanotube (CNT) forest and elicit a piezoresistive response as the CNT forest impinges on electrodes in a micropore when the hair is deflected due to viscous drag forces. Particle image velocimetry is used to measure the flow field allowing for the resulting moment and force acting on the hair to be correlated with the electrical response. It is demonstrated that the AHS provides estimates for the locations of both the stagnation and separation in steady flow. From this, a simulation of a heading estimation is presented to demonstrate a potential application for hair sensors. These results motivate the construction of large arrays of hair sensors for imaging and resolving flow structures in real time. (paper)

  5. Unique encoding for streamline topologies of incompressible and inviscid flows in multiply connected domains

    Energy Technology Data Exchange (ETDEWEB)

    Sakajo, T [Department of Mathematics, Kyoto University, Kitashirakawa Oiwake-cho, Sakyo-ku, Kyoto 606-8502 (Japan); Sawamura, Y; Yokoyama, T, E-mail: sakajo@math.kyoto-u.ac.jp [JST CREST, Kawaguchi, Saitama 332-0012 (Japan)

    2014-06-01

    This study considers the flow of incompressible and inviscid fluid in two-dimensional multiply connected domains. For such flows, encoding algorithms to assign a unique sequence of words to any structurally stable streamline topology based on the theory presented by Yokoyama and Sakajo (2013 Proc. R. Soc. A 469 20120558) are proposed. As an application, we utilize the algorithms to characterize the evolution of an incompressible and viscid flow around a flat plate inclined to the uniform flow in terms of the change of the word representations for their instantaneous streamline topologies. (papers)

  6. Categorization of flow conditions using Integral quantities for characterizing stagnation and recirculation

    International Nuclear Information System (INIS)

    Han, M.H.; Hwang, W.T.; Jeong, H.J.; Kim, E.H.

    2008-01-01

    This paper describes a method for categorizing an atmospheric flow condition of a site by using integral quantities for characterizing stagnation and recirculation. Authors have devised a method for categorizing flow conditions using distribution curves which represent the flow condition of the whole of Korea. It was found that the flow conditions for four nuclear power plant sites were good enough from a meteorological aspect. Among the four sites, Kori nuclear power plant site which is located at the south-eastern part of the Korean peninsular shows the best condition. Meteorological condition is the key factor for estimating the environmental effects of a nuclear facility. The devised method can be used for assessing the relative environmental risk of a nuclear facility with only meteorological data. And the devised categorization method can be used for choosing a suitable site for an industrial facility such as a nuclear power plant and a chemical complex. (author)

  7. Stagnation point flow towards nonlinear stretching surface with Cattaneo-Christov heat flux

    Science.gov (United States)

    Hayat, T.; Zubair, M.; Ayub, M.; Waqas, M.; Alsaedi, A.

    2016-10-01

    Here the influence of the non-Fourier heat flux in a two-dimensional (2D) stagnation point flow of Eyring-Powell liquid towards a nonlinear stretched surface is reported. The stretching surface is of variable thickness. Thermal conductivity of fluid is taken temperature-dependent. Ordinary differential systems are obtained through the implementation of meaningful transformations. The reduced non-dimensional expressions are solved for the convergent series solutions. Convergence interval is obtained for the computed solutions. Graphical results are displayed and analyzed in detail for the velocity, temperature and skin friction coefficient. The obtained results reveal that the temperature gradient enhances when the thermal relaxation parameter is increased.

  8. Melting heat transfer in boundary layer stagnation-point flow towards a stretching/shrinking sheet

    International Nuclear Information System (INIS)

    Bachok, Norfifah; Ishak, Anuar; Pop, Ioan

    2010-01-01

    An analysis is carried out to study the steady two-dimensional stagnation-point flow and heat transfer from a warm, laminar liquid flow to a melting stretching/shrinking sheet. The governing partial differential equations are converted into ordinary differential equations by similarity transformation, before being solved numerically using the Runge-Kutta-Fehlberg method. Results for the skin friction coefficient, local Nusselt number, velocity profiles as well as temperature profiles are presented for different values of the governing parameters. Effects of the melting parameter, stretching/shrinking parameter and Prandtl number on the flow and heat transfer characteristics are thoroughly examined. Different from a stretching sheet, it is found that the solutions for a shrinking sheet are non-unique.

  9. THERMOSS: a thermohydraulic model of flow stagnation in a horizontal fuel channel

    International Nuclear Information System (INIS)

    Gulshani, P.; Caplan, M.Z.; Spinks, N.J.

    1984-01-01

    Following a postulated inlet-side small break in the CANDU reactor, emergency coolant is injected to refull the horizontal fuel channels and remove the decay heat. As part of the accident analysis, the effects of loss of forced circulation during the accident are predicted. A break size exists for which, at the end of pump rundown, the break force balances the natural circulation force and the channel flow is reduced to near zero. The subcooled, stagnant channel condition is referred to as the standing-start condition. Subsequently, the channel coolant boils and stratifies. Eventually the steam flow from the channel heats up the endfitting to the saturation temperature and reaches the vertical feeder. The resulting buoyancy-induced flow then refills the channel. One dimensional, two-fluid conservation equations are solved in closed form to predict the duration of stagnation. In this calculation the channel water level is an important intermediate variable because it determines the amount of steam production

  10. Stagnation-point flow of second grade nanofluid towards a nonlinear stretching surface with variable thickness

    Directory of Open Access Journals (Sweden)

    Rai Sajjad Saif

    Full Text Available This paper investigates the stagnation point flow of second grade nanomaterial towards a nonlinear stretching surface subject to variable surface thickness. The process of heat transfer is examined through the melting heat and mixed convection effects. Further novel features regarding Brownian motion and thermophoresis are present. Boundary-layer approximation is employed in the problem formulation. Momentum, energy and concentration equations are converted into the non-linear ordinary differential system through the appropriate transformations. Convergent solutions for resulting problem are computed. Behaviors of various sundry variables on temperature and concentration are studied in detail. The skin friction coefficient and heat and mass transfer rates are also computed and analyzed. Our results indicate that the temperature and concentration distributions are enhanced for larger values of thermophoresis parameter. Further the present work is hoped to be useful in improving the performance of heat transfer of base fluid. Keywords: Stagnation-point flow, Second grade fluid, Nanoparticles, Melting heat process, Nonlinear stretching surface, Variable surface thickness

  11. Thermo-diffusion effects on MHD stagnation point flow towards a stretching sheet in a nanofluid

    Directory of Open Access Journals (Sweden)

    Umar Khan

    2014-09-01

    Full Text Available Thermodiffusion effects on stagnation point flow of a nanofluid towards a stretching surface with applied magnetic field is presented. Similarity transforms are applied to reduce the equations that govern the flow to a system of nonlinear ordinary differential equations. Runge-Kutta-Fehlberg method is applied to solve the system. Results are compared with existing solutions that are special cases to our problem. Concrete graphical analysis is carried out to study the effects of different emerging parameters such as stretching ratio A, magnetic influence parameter M, Prandtl number Pr, Lewis number Le, Brownian motion parameter Nb, thermophoresis parameter Nt, nanofluid Lewis number Ln, modified Dufour parameter Nd and Dufour solutal number Ld coupled with comprehensive discussions. Numerical effects of local Nusselt number, local Sherwood number and nanofluid Sherwood number are also discussed.

  12. A numerical study for off-centered stagnation flow towards a rotating disc

    Directory of Open Access Journals (Sweden)

    M. Heydari

    2015-09-01

    Full Text Available In this investigation, a semi-numerical method based on Bernstein polynomials for solving off-centered stagnation flow towards a rotating disc is introduced. This method expands the desired solutions in terms of a set of Bernstein polynomials over a closed interval and then makes use of the tau method to determine the expansion coefficients to construct approximate solutions. This method can satisfy boundary conditions at infinity. The properties of Bernstein polynomials are presented and are utilized to reduce the solution of governing nonlinear equations and their associated boundary conditions to the solution of algebraic equations. Graphical results are presented to investigate the influence of the rotation ratio α on the radial velocity, azimuthal velocity and the induced velocities. A comparative study with the previous results of viscous fluid flow in the literature is made.

  13. Nonlinear radiative heat transfer to stagnation-point flow of Sisko fluid past a stretching cylinder

    Directory of Open Access Journals (Sweden)

    Masood Khan

    2016-05-01

    Full Text Available In the present paper, we endeavor to perform a numerical analysis in connection with the nonlinear radiative stagnation-point flow and heat transfer to Sisko fluid past a stretching cylinder in the presence of convective boundary conditions. The influence of thermal radiation using nonlinear Rosseland approximation is explored. The numerical solutions of transformed governing equations are calculated through forth order Runge-Kutta method using shooting technique. With the help of graphs and tables, the influence of non-dimensional parameters on velocity and temperature along with the local skin friction and Nusselt number is discussed. The results reveal that the temperature increases however, heat transfer from the surface of cylinder decreases with the increasing values of thermal radiation and temperature ratio parameters. Moreover, the authenticity of numerical solutions is validated by finding their good agreement with the HAM solutions.

  14. Stagnation point flow and heat transfer over a nonlinear shrinking sheet with slip effects

    Directory of Open Access Journals (Sweden)

    N.F. Fauzi

    2015-12-01

    Full Text Available In this paper, an investigation is performed to analyze the effects of the slip parameters A and B on the steady stagnation-point flow and heat transfer due to a shrinking sheet in a viscous and incompressible fluid. Using similarity transformations, the governing boundary layer equations are transformed into the nonlinear ordinary (similar differential equations. The transformed equations are solved numerically using the shooting method. The dual solutions for velocity and temperature distribution exist for certain values of the positive constant velocity and temperature slip parameters. Likewise, a stability analysis has been performed to find the nature of the dual solutions. The velocity slip will delay the boundary layer separation whereas the temperature slip does not affect the boundary layer separation.

  15. Nonlinear radiative heat transfer to stagnation-point flow of Sisko fluid past a stretching cylinder

    Energy Technology Data Exchange (ETDEWEB)

    Khan, Masood [Department of Mathematics, Quaid-i-Azam University, Islamabad 44000 (Pakistan); Malik, Rabia, E-mail: rabiamalik.qau@gmail.com [Department of Mathematics, Quaid-i-Azam University, Islamabad 44000 (Pakistan); Department of Mathematics and Statistics, International Islamic University Islamabad 44000 (Pakistan); Hussain, M. [Department of Sciences and Humanities, National University of Computer and Emerging Sciences, Islamabad 44000 (Pakistan)

    2016-05-15

    In the present paper, we endeavor to perform a numerical analysis in connection with the nonlinear radiative stagnation-point flow and heat transfer to Sisko fluid past a stretching cylinder in the presence of convective boundary conditions. The influence of thermal radiation using nonlinear Rosseland approximation is explored. The numerical solutions of transformed governing equations are calculated through forth order Runge-Kutta method using shooting technique. With the help of graphs and tables, the influence of non-dimensional parameters on velocity and temperature along with the local skin friction and Nusselt number is discussed. The results reveal that the temperature increases however, heat transfer from the surface of cylinder decreases with the increasing values of thermal radiation and temperature ratio parameters. Moreover, the authenticity of numerical solutions is validated by finding their good agreement with the HAM solutions.

  16. Melting heat transfer in stagnation point flow of carbon nanotubes towards variable thickness surface

    Directory of Open Access Journals (Sweden)

    T. Hayat

    2016-01-01

    Full Text Available This work concentrates on the mathematical modeling for stagnation point flow of nanofluids over an impermeable stretching sheet with variable thickness. Carbon nanotubes [single-wall carbon nanotubes (SWCNTs and multi-wall carbon nanotubes (MWCNTs] as the nanoparticles are utilized. Water and kerosene oil are taken as the base fluids. Heat transfer through melting effect is discussed. Transformation procedure is adapted to obtain the non-linear ordinary differential equations from the fundamental laws of mass, linear momentum and energy. The optimal values of convergence control parameters and corresponding individual and total residual errors for SWCNTs and MWCNTs are computed by means of homotopy analysis method (HAM based BVPh 2.0. Characteristics of different involved parameters on the velocity, temperature, skin friction coefficient and Nusselt number are discussed. Higher velocity profile is observed for wall thickness parameter in case of water carbon nanotubes when compared with the kerosene oil carbon nanotubes.

  17. MHD stagnation point flow by a permeable stretching cylinder with Soret-Dufour effects

    Institute of Scientific and Technical Information of China (English)

    M Ramzan; M Farooq; T Hayat; A Alsaedi; J Cao

    2015-01-01

    Combined effects of Soret (thermal-diffusion) and Dufour (diffusion-thermo) in MHD stagnation point flow by a permeable stretching cylinder were studied. Analysis was examined in the presence of heat generation/absorption and chemical reaction. The laws of conservation of mass, momentum, energy and concentration are found to lead to the mathematical development of the problem. Suitable transformations were used to convert the nonlinear partial differential equations into the ordinary differential equations. The series solutions of boundary layer equations through momentum, energy and concentration equations were obtained. Convergence of the developed series solutions was discussed via plots and numerical values. The behaviors of different physical parameters on the velocity components, temperature and concentration were obtained. Numerical values of Nusselt number, skin friction and Sherwood number with different parameters were computed and analyzed. It is found that Dufour and Soret numbers result in the enhancement of temperature and concentration distributions, respectively.

  18. Analysis of stagnation point flow of an upper-convected Maxwell fluid

    Directory of Open Access Journals (Sweden)

    Joseph E. Paullet

    2017-12-01

    Full Text Available Several recent papers have investigated the two-dimensional stagnation point flow of an upper-convected Maxwell fluid by employing a similarity change of variable to reduce the governing PDEs to a nonlinear third order ODE boundary value problem (BVP. In these previous works, the BVP was studied numerically and several conjectures regarding the existence and behavior of the solutions were made. The purpose of this article is to mathematically verify these conjectures. We prove the existence of a solution to the BVP for all relevant values of the elasticity parameter. We also prove that this solution has monotonically increasing first derivative, thus verifying the conjecture that no ``overshoot'' of the boundary condition occurs. Uniqueness results are presented for a large range of parameter space and bounds on the skin friction coefficient are calculated.

  19. Streamline topologies near simple degenerate critical points in two-dimensional flow away from boundaries

    DEFF Research Database (Denmark)

    Brøns, Morten; Hartnack, Johan Nicolai

    1998-01-01

    Streamline patterns and their bifurcations in two-dimensional incompressible flow are investigated from a topological point of view. The velocity field is expanded at a point in the fluid, and the expansion coefficients are considered as bifurcation parameters. A series of non-linear coordinate c...

  20. Streamline topologies near simple degenerate critical points in two-dimensional flow away from boundaries

    DEFF Research Database (Denmark)

    Brøns, Morten; Hartnack, Johan Nicolai

    1999-01-01

    Streamline patterns and their bifurcations in two-dimensional incompressible flow are investigated from a topological point of view. The velocity field is expanded at a point in the fluid, and the expansion coefficients are considered as bifurcation parameters. A series of nonlinear coordinate ch...

  1. Mean streamline analysis for performance prediction of cross-flow fans

    International Nuclear Information System (INIS)

    Kim, Jae Won; Oh, Hyoung Woo

    2004-01-01

    This paper presents the mean streamline analysis using the empirical loss correlations for performance prediction of cross-flow fans. Comparison of overall performance predictions with test data of a cross-flow fan system with a simplified vortex wall scroll casing and with the published experimental characteristics for a cross-flow fan has been carried out to demonstrate the accuracy of the proposed method. Predicted performance curves by the present mean streamline analysis agree well with experimental data for two different cross-flow fans over the normal operating conditions. The prediction method presented herein can be used efficiently as a tool for the preliminary design and performance analysis of general-purpose cross-flow fans

  2. Analytical study of the non orthogonal stagnation point flow of a micro polar fluid

    Directory of Open Access Journals (Sweden)

    M. Ali. Abbas

    2017-01-01

    Full Text Available In this paper we consider the steady two dimensional flow of micro polar fluids on a flat plate. The flow under discussion is the modified Hiemenz flow for a micro polar fluid which occurs in the hjkns + skms boundary layer near an orthogonal stagnation point. The full governing equation reduced to a modified Hiemenz flow. The solution to the boundary value problem is governed by two non dimensional parameters, the material parameter K and the ratio of the micro rotation to skin friction parameter n. The obtained nonlinear coupled ordinary differential equations are solved by using the Homotopy perturbation method. Comparison between numerical and analytical solutions of the problem is shown in tables form for different values of the governing parameters K and n. Effects of the material parameter K on the velocity profile and microrotation profiles for different cases of n are discussed graphically as well as numerically. Velocity profile decreases as the material parameter K increases and the microrotation profile increases as the material parameter K increases for different cases of n.

  3. Changes of the corrosion potential of iron in stagnation and flow conditions and their relationship with metal release.

    Science.gov (United States)

    Fabbricino, Massimiliano; Korshin, Gregory V

    2014-10-01

    This study examined the behavior of corrosion potential (Ecorr) of iron exposed to drinking water during episodes of stagnation and flow. These measurements showed that during stagnation episodes, Ecorr values decrease prominently and consistently. This decrease is initially rapid but it becomes slower as the stagnation time increases. During flow episodes, the Ecorr values increase and reach a quasi-steady state. Experiments with varying concentrations of dissolved oxygen showed that the decrease of Ecorr values characteristic for stagnation is likely to be associated with the consumption of dissolved oxygen by the exposed metal. The corrosion potential of iron and its changes during stagnation were sensitive to the concentrations of sulfate and chloride ions. Measurements of iron release showed that both the absolute values of Ecorr measured prior to or after stagnation episodes were well correlated with the logarithms of concentrations of total iron. The slope of this dependence showed that the observed correlations between Ecorr values and Fe concentrations corresponded to the coupling between the oxidant consumption and changes of Fe redox status. These results demonstrate that in situ Ecorr measurements can be a sensitive method with which to ascertain effects of hydrodynamic conditions and short-term variations of water chemistry on metal release and corrosion in drinking water. This approach is valuable practically because Ecorr measurements are precise, can be carried out in situ with any desired time resolution, do not affect the state of exposed surface in any extent and can be carried out with readily available equipment. Copyright © 2014 Elsevier Ltd. All rights reserved.

  4. Large amplitude oscillation of a boiling bubble growing at a wall in stagnation flow

    International Nuclear Information System (INIS)

    Geld, C.W.M. van der; Berg, R. van de; Peukert, P.

    2009-01-01

    A boiling bubble is created on an artificial site that is part of a bubble generator that is mounted at the center of a pipe. Downflow of water impinges on the bubble generator and creates a stagnation flow above the artificial cavity. Stable axisymmetric elongation in the direction away from the wall and multiple shape oscillation cycles are observed. The time of growth and attachment is typically of the order of 250 ms. Amongst the length scales that characterize the bubble shape is the radius of curvature of the upper part of the bubble, R. The period of oscillation, T, is strongly dependent on time, as is R. The parameters C and m in the defining equation T = C R m √(ρL/σ) have been determined by fitting to data of more than 100 bubbles. For each operating condition, the same values of C and m have been found. The value of m is 1.49 ± 0.02, which is explained from the continuous growth of the bubble and from the relation to the period of oscillation of a free bubble deforming in the fundamental mode corresponding to the third Legendre Polynomial. For the latter, R is the radius of the volume-equivalent sphere, R 0 , and C is √12, while for attached boiling bubbles C is found to amount 1.9√12. The difference is easily explained from the continuous growth, difference in definition, finite amplitude oscillation and proximity of the wall. (author)

  5. Numerical modeling of time-dependent bio-convective stagnation flow of a nanofluid in slip regime

    Directory of Open Access Journals (Sweden)

    Rakesh Kumar

    Full Text Available A numerical investigation of unsteady stagnation point flow of bioconvective nanofluid due to an exponential deforming surface is made in this research. The effects of Brownian diffusion, thermophoresis, slip velocity and thermal jump are incorporated in the nanofluid model. By utilizing similarity transformations, the highly nonlinear partial differential equations governing present nano-bioconvective boundary layer phenomenon are reduced into ordinary differential system. The resultant expressions are solved for numerical solution by employing a well-known implicit finite difference approach termed as Keller-box method (KBM. The influence of involved parameters (unsteadiness, bioconvection Schmidt number, velocity slip, thermal jump, thermophoresis, Schmidt number, Brownian motion, bioconvection Peclet number on the distributions of velocity, temperature, nanoparticle and motile microorganisms concentrations, the coefficient of local skin-friction, rate of heat transport, Sherwood number and local density motile microorganisms are exhibited through graphs and tables. Keywords: Unsteadiness, Bio-convection, Slip regime, Stagnation point flow, Numerical modeling

  6. Investigation of Three-Dimensional Axisymmetric Unsteady Stagnation-Point Flow and Heat Transfer Impinging on an Accelerated Flat Plate

    OpenAIRE

    ali shokrgozar abbasi; Asghar Baradaran Rahimi; Hamidreza Mozayeni

    2016-01-01

    General formulation and solution of Navier-Stokes and energy equations are sought in the study of threedimensional axisymmetric unsteady stagnation-point flow and heat transfer impinging on a flat plate when the plate is moving with variable velocity and acceleration towards the main stream or away from it. As an application, among others, this accelerated plate can be assumed as a solidification front which is being formed with variable velocity. An external fluid, along z - directi...

  7. Large amplitude oscillation of a boiling bubble growing at a wall in stagnation flow

    Energy Technology Data Exchange (ETDEWEB)

    Geld, C.W.M. van der; Berg, R. van de; Peukert, P. [Eindhoven University of Technology, Eindhoven (Netherlands). Faculty of Mechanical Engineering], e-mail: C.W.M._v.d.Geld@tue.nl

    2009-07-01

    A boiling bubble is created on an artificial site that is part of a bubble generator that is mounted at the center of a pipe. Downflow of water impinges on the bubble generator and creates a stagnation flow above the artificial cavity. Stable axisymmetric elongation in the direction away from the wall and multiple shape oscillation cycles are observed. The time of growth and attachment is typically of the order of 250 ms. Amongst the length scales that characterize the bubble shape is the radius of curvature of the upper part of the bubble, R. The period of oscillation, T, is strongly dependent on time, as is R. The parameters C and m in the defining equation T = C R{sup m} {radical}({rho}L/{sigma}) have been determined by fitting to data of more than 100 bubbles. For each operating condition, the same values of C and m have been found. The value of m is 1.49 {+-} 0.02, which is explained from the continuous growth of the bubble and from the relation to the period of oscillation of a free bubble deforming in the fundamental mode corresponding to the third Legendre Polynomial. For the latter, R is the radius of the volume-equivalent sphere, R{sub 0}, and C is {radical}12, while for attached boiling bubbles C is found to amount 1.9{radical}12. The difference is easily explained from the continuous growth, difference in definition, finite amplitude oscillation and proximity of the wall. (author)

  8. THERMOSS: A thermohydraulic model of flow stagnation in a horizontal fuel channel

    International Nuclear Information System (INIS)

    Gulshani, P.; Caplan, M.Z.; Spinks, N.J.

    1984-01-01

    A model, called THERMOSS, is developed to compute the duration of stagnation in a CANDU reactor fuel channel with subcooled, stagnant initial conditions. The model solves, in closed form, the one dimensional, two-fluid conservation equations. In the computation of the duration of stagnation, the channel water level is an important intermediate variable because it determines the amount of steam production. A feature of the model is that water level is determined by a momentum balance between frictional pressure drop in the steam phase and hydrostatic head in the liquid phase. This is in contrast to an ealier model in which the level was determined from mass balance considerations. A satisfactory agreement between the predicted and experimentally observed channel water level and duration of stagnation is obtained. (orig.)

  9. Characteristics of buoyancy force on stagnation point flow with magneto-nanoparticles and zero mass flux condition

    Directory of Open Access Journals (Sweden)

    Iftikhar Uddin

    2018-03-01

    Full Text Available This attempt dedicated to the solution of buoyancy effect over a stretching sheet in existence of MHD stagnation point flow with convective boundary conditions. Thermophoresis and Brownian motion aspects are included. Incompressible fluid is electrically conducted in the presence of varying magnetic field. Boundary layer analysis is used to develop the mathematical formulation. Zero mass flux condition is considered at the boundary. Non-linear ordinary differential system of equations is constructed by means of proper transformations. Interval of convergence via numerical data and plots are developed. Characteristics of involved variables on the velocity, temperature and concentration distributions are sketched and discussed. Features of correlated parameters on Cf and Nu are examined by means of tables. It is found that buoyancy ratio and magnetic parameters increase and reduce the velocity field. Further opposite feature is noticed for higher values of thermophoresis and Brownian motion parameters on concentration distribution. Keywords: Stagnation point, MHD, Nanoparticles, Zero mass flux condition

  10. Flame stabilization and mixing characteristics in a Stagnation Point Reverse Flow combustor

    Science.gov (United States)

    Bobba, Mohan K.

    A novel combustor design, referred to as the Stagnation Point Reverse-Flow (SPRF) combustor, was recently developed that is able to operate stably at very lean fuel-air mixtures and with low NOx emissions even when the fuel and air are not premixed before entering the combustor. The primary objective of this work is to elucidate the underlying physics behind the excellent stability and emissions performance of the SPRF combustor. The approach is to experimentally characterize velocities, species mixing, heat release and flame structure in an atmospheric pressure SPRF combustor with the help of various optical diagnostic techniques: OH PLIF, chemiluminescence imaging, PIV and Spontaneous Raman Scattering. Results indicate that the combustor is primarily stabilized in a region downstream of the injector that is characterized by low average velocities and high turbulence levels; this is also the region where most of the heat release occurs. High turbulence levels in the shear layer lead to increased product entrainment levels, elevating the reaction rates and thereby enhancing the combustor stability. The effect of product entrainment on chemical timescales and the flame structure is illustrated with simple reactor models. Although reactants are found to burn in a highly preheated (1300 K) and turbulent environment due to mixing with hot product gases, the residence times are sufficiently long compared to the ignition timescales such that the reactants do not autoignite. Turbulent flame structure analysis indicates that the flame is primarily in the thin reaction zones regime throughout the combustor, and it tends to become more flamelet like with increasing distance from the injector. Fuel-air mixing measurements in case of non-premixed operation indicate that the fuel is shielded from hot products until it is fully mixed with air, providing nearly premixed performance without the safety issues associated with premixing. The reduction in NOx emissions in the SPRF

  11. The effect of mixing rates on the formation and growth of condensation aerosols in a model stagnation flow

    KAUST Repository

    Alshaarawi, Amjad; Bisetti, Fabrizio

    2015-01-01

    A steady, laminar stagnation flow configuration is adopted to investigate numerically the interaction between condensing aerosol particles and gas-phase transport across a canonical mixing layer. The mixing rates are varied by adjusting the velocity and length scales of the stagnation flow parametrically. The effect of mixing rates on particle concentration, polydispersity, and mean droplet diameter is explored and discussed. This numerical study reveals a complex response of the aerosol to varying flow times. Depending on the flow time, the variation of the particle concentration in response to varying mixing rates falls into one of the two regimes. For fast mixing rates, the number density and volume fraction of the condensing particles increase with residence time (nucleation regime). On the contrary, for low mixing rates, number density decreases with residence time and volume fraction reaches a plateau (condensation regime). It is shown that vapor scavenging by the aerosol phase is key to explaining the transition between these two regimes. The results reported here are general and illustrate genuine features of the evolution of aerosols forming by condensation of supersaturated vapor from heat and mass transport across mixing layers.

  12. Heat transfer in an axisymmetric stagnation flow at high Reynolds numbers on a cylinder using perturbation techniques

    International Nuclear Information System (INIS)

    Rahimi, A. B.

    2003-01-01

    Although there are many papers on the subject of heat transfer in an axisymmetric stagnation flow on a cylinder, the available knowledge is mainly for low Reynolds numbers and not much information exists for the same problem at large Reynolds numbers. In this work, the problem of heat transfer in an axisymmetric stagnation flow on a cylinder is solved at large Reynolds numbers using perturbation techniques. Starting from Navier-Stokes equations within a boundary layer approximation and using similarity transformations, the governing equations are obtained in the form of differential equations. The inverse of the Reynolds number is introduced as the perturbation parameter. This parameter appears in front of the highest-order terms and, as it tends to zero, reduces the order of the governing equations and produces singularities. In this paper, the flow field is divided into two regions; rapid changes in the region near wall and slow changes away from the wall. Thus, the flow is found to have dual-layer characteristics. Using inner and outer expansion produces uniform values of the relevant quantities

  13. The effect of mixing rates on the formation and growth of condensation aerosols in a model stagnation flow

    KAUST Repository

    Alshaarawi, Amjad

    2015-03-01

    A steady, laminar stagnation flow configuration is adopted to investigate numerically the interaction between condensing aerosol particles and gas-phase transport across a canonical mixing layer. The mixing rates are varied by adjusting the velocity and length scales of the stagnation flow parametrically. The effect of mixing rates on particle concentration, polydispersity, and mean droplet diameter is explored and discussed. This numerical study reveals a complex response of the aerosol to varying flow times. Depending on the flow time, the variation of the particle concentration in response to varying mixing rates falls into one of the two regimes. For fast mixing rates, the number density and volume fraction of the condensing particles increase with residence time (nucleation regime). On the contrary, for low mixing rates, number density decreases with residence time and volume fraction reaches a plateau (condensation regime). It is shown that vapor scavenging by the aerosol phase is key to explaining the transition between these two regimes. The results reported here are general and illustrate genuine features of the evolution of aerosols forming by condensation of supersaturated vapor from heat and mass transport across mixing layers.

  14. Stagnation point flow on bioconvection nanofluid over a stretching/shrinking surface with velocity and thermal slip effects

    Science.gov (United States)

    Chan, Sze Qi; Aman, Fazlina; Mansur, Syahira

    2017-09-01

    Nanofluid containing nanometer sized particles has become an ideal thermal conductivity medium for the flow and heat transfer in many industrial and engineering applications due to their high rate of heat transfer. However, swimming microorganisms are imposed into the nanofluid to overcome the instability of nanoparticles due to a bioconvection phenomenon. This paper investigates the stagnation point flow on bioconvection heat transfer of a nanofluid over a stretching/shrinking surface containing gyrotactic microorganisms. Velocity and thermal slip effects are the two conditions incorporated into the model. Similarity transformation is applied to reduce the governing nonlinear partial differential equations into the nonlinear ordinary differential equations. The transformed equations are then solved numerically. The results are displayed in the form of graphs and tables. The effects of these governing parameters on the skin friction coefficient, local Nusselt number, local Sherwood number and the local density of the motile microorganisms are analysed and discussed in details.

  15. Numerical study of unsteady MHD oblique stagnation point flow and heat transfer due to an oscillating stream

    Science.gov (United States)

    Javed, T.; Ghaffari, A.; Ahmad, H.

    2016-05-01

    The unsteady stagnation point flow impinging obliquely on a flat plate in presence of a uniform applied magnetic field due to an oscillating stream has been studied. The governing partial differential equations are transformed into dimensionless form and the stream function is expressed in terms of Hiemenz and tangential components. The dimensionless partial differential equations are solved numerically by using well-known implicit finite difference scheme named as Keller-box method. The obtained results are compared with those available in the literature. It is observed that the results are in excellent agreement with the previous studies. The effects of pertinent parameters involved in the problem namely magnetic parameter, Prandtl number and impinging angle on flow and heat transfer characteristics are illustrated through graphs. It is observed that the influence of magnetic field strength increases the fluid velocity and by the increase of obliqueness parameter, the skin friction increases.

  16. Development of a Streamlined Work Flow for Handling Patients' Genetic Testing Insurance Authorizations.

    Science.gov (United States)

    Uhlmann, Wendy R; Schwalm, Katie; Raymond, Victoria M

    2017-08-01

    Obtaining genetic testing insurance authorizations for patients is a complex, time-involved process often requiring genetic counselor (GC) and physician involvement. In an effort to mitigate this complexity and meet the increasing number of genetic testing insurance authorization requests, GCs formed a novel partnership with an industrial engineer (IE) and a patient services associate (PSA) to develop a streamlined work flow. Eight genetics clinics and five specialty clinics at the University of Michigan were surveyed to obtain benchmarking data. Tasks needed for genetic testing insurance authorization were outlined and time-saving work flow changes were introduced including 1) creation of an Excel password-protected shared database between GCs and PSAs, used for initiating insurance authorization requests, tracking and follow-up 2) instituting the PSAs sending GCs a pre-clinic email noting each patients' genetic testing insurance coverage 3) inclusion of test medical necessity documentation in the clinic visit summary note instead of writing a separate insurance letter and 4) PSAs development of a manual with insurance providers and genetic testing laboratories information. These work flow changes made it more efficient to request and track genetic testing insurance authorizations for patients, enhanced GCs and PSAs communication, and reduced tasks done by clinicians.

  17. Unsteady mixed convection flow of a micro-polar fluid near the stagnation point on a vertical surface

    Energy Technology Data Exchange (ETDEWEB)

    Lok, Y.Y. [Center for Academic Services, Kolej Universiti Teknikal Kebangsaan Malaysia, 75450 Ayer Keroh, Melaka (Malaysia); Amin, N. [Department of Mathematics, Universiti Teknologi Malaysia, 81310 Johor Bahru, Johor (Malaysia); Pop, I. [Faculty of Mathematics, University of Cluj, R-3400 Cluj, CP 253 (Romania)

    2006-12-15

    The unsteady mixed convection boundary-layer flow of a micro-polar fluid near the region of the stagnation point on a double-infinite vertical flat plate is studied. It is assumed that the unsteadiness is caused by the impulsive motion of the free stream velocity and by sudden increase or sudden decrease in the surface temperature from the uniform ambient temperature. The problem is reduced to a system of non-dimensional partial differential equations, which is solved numerically using the Keller-box method. This method may present well-behaved solutions for the transient (small time) solution and those of the steady-state flow (large time) solution. It was found that there is a smooth transition from the small-time solution (initial unsteady-state flow) to the large-time solution (final steady-state flow). Further, it is shown that for both assisting and opposing cases and a fixed value of the Prandtl number, the reduced steady-state skin friction and the steady-state heat transfer from the wall (or Nusselt number) decrease with the increase of the material parameter. On the other hand, it is shown that with the increase of the Prandtl number and a fixed value of the material parameter, the reduced steady-state skin friction decreases when the flow is assisting and it increases when the flow is opposing. (author)

  18. Local similar solution of MHD stagnation point flow in Carreau fluid over a non-linear stretched surface with double stratified medium

    Directory of Open Access Journals (Sweden)

    M. Farooq

    Full Text Available This article studies MHD double stratified stagnation point flow of Carreau fluid towards a non linear stretchable surface with radiation. Features of heat and mass transfer are evaluated by using convective boundary conditions. Resulting nonlinear problems are solved and studied for the velocity, temperature and concentration fields. Heat and mass transfer rates in addition to skin friction are discussed. Besides this for the verification of the present findings, the results of presented analysis have been compared with the available works in particular situations and reasonable agreement is noted. Keywords: Convective boundary condition, Thermal radiation, Double stratification, Stagnation point flow

  19. Heat transfer in boundary layer stagnation-point flow towards a shrinking sheet with non-uniform heat flux

    International Nuclear Information System (INIS)

    Bhattacharyya Krishnendu

    2013-01-01

    In this paper, the effect of non-uniform heat flux on heat transfer in boundary layer stagnation-point flow over a shrinking sheet is studied. The variable boundary heat fluxes are considered of two types: direct power-law variation with the distance along the sheet and inverse power-law variation with the distance. The governing partial differential equations (PDEs) are transformed into non linear self-similar ordinary differential equations (ODEs) by similarity transformations, and then those are solved using very efficient shooting method. The direct variation and inverse variation of heat flux along the sheet have completely different effects on the temperature distribution. Moreover, the heat transfer characteristics in the presence of non-uniform heat flux for several values of physical parameters are also found to be interesting

  20. Unsteady separated stagnation-point flow and heat transfer of a viscous fluid over a moving flat surface

    Science.gov (United States)

    Dholey, S.

    2018-04-01

    In this paper, we have investigated numerically the laminar unsteady separated stagnation-point flow and heat transfer of a viscous fluid over a moving flat surface in the presence of a time dependent free stream velocity which causes the unsteadiness of this flow problem. The plate is assumed to move in the same or opposite direction of the free stream velocity. The flow is therefore governed by the velocity ratio parameter λ (ratio of the plate velocity to the free stream velocity) and the unsteadiness parameter β. When the plate surface moves in the same direction of the free stream velocity (i.e., when λ > 0), the solution of this flow problem continues for any given value of β. On the other hand, when they move in opposite directions (i.e., when λ heat transfer analysis is that for a given value of λ(= 0), first the heat transfer rate increases with the increase of the Prandtl number Pr and after attaining a maximum value, it decreases and finally tends to be zero for large values of Pr depending upon the values of β > 0. On the contrary, for a given value of β(≤ 0), the rate of heat transfer increases consistently with the increase of Pr.

  1. Flow stagnation volume and abdominal aortic aneurysm growth: Insights from patient-specific computational flow dynamics of Lagrangian-coherent structures.

    Science.gov (United States)

    Joly, Florian; Soulez, Gilles; Garcia, Damien; Lessard, Simon; Kauffmann, Claude

    2018-01-01

    Abdominal aortic aneurysms (AAA) are localized, commonly-occurring dilations of the aorta. When equilibrium between blood pressure (loading) and wall mechanical resistance is lost, rupture ensues, and patient death follows, if not treated immediately. Experimental and numerical analyses of flow patterns in arteries show direct correlations between wall shear stress and wall mechano-adaptation with the development of zones prone to thrombus formation. For further insights into AAA flow topology/growth interaction, a workout of patient-specific computational flow dynamics (CFD) is proposed to compute finite-time Lyapunov exponents and extract Lagrangian-coherent structures (LCS). This computational model was first compared with 4-D phase-contrast magnetic resonance imaging (MRI) in 5 patients. To better understand the impact of flow topology and transport on AAA growth, hyperbolic, repelling LCS were computed in 1 patient during 8-year follow-up, including 9 volumetric morphologic AAA measures by computed tomography-angiography (CTA). LCS defined barriers to Lagrangian jet cores entering AAA. Domains enclosed between LCS and the aortic wall were considered to be stagnation zones. Their evolution was studied during AAA growth. Good correlation - 2-D cross-correlation coefficients of 0.65, 0.86 and 0.082 (min, max, SD) - was obtained between numerical simulations and 4-D MRI acquisitions in 6 specific cross-sections from 4 patients. In follow-up study, LCS divided AAA lumens into 3 dynamically-isolated zones: 2 stagnation volumes lying in dilated portions of the AAA, and circulating volume connecting the inlet to the outlet. The volume of each zone was tracked over time. Although circulating volume remained unchanged during 8-year follow-up, the AAA lumen and main stagnation zones grew significantly (8 cm 3 /year and 6 cm 3 /year, respectively). This study reveals that transient transport topology can be quantified in patient-specific AAA during disease progression

  2. Stagnation zone formation on the axis of a closed vortex flow

    DEFF Research Database (Denmark)

    Naumov, I. V.; Okulov, Valery; Mikkelsen, Robert Flemming

    2014-01-01

    The features of developing a counterflow zone (bubble-mode vortex breakdown or vortex explosion) at the center of an intensively swirled flow produced in a liquid-filled cylindrical container with a rotating endwall have been studied. The observation showed that the scenario of developing a bubbl......-mode breakdown zone with generation of counterflow is the same for cylinders with low or high aspect ratio, and it remains independent of stationary-nonstationary transition boundary for the main vortex flow....

  3. Boundary layer flow of an oldroyd-b fluid in the region of stagnation point over a stretching sheet

    International Nuclear Information System (INIS)

    Sajid, M.

    2012-01-01

    The mathematical modeling for the two-dimensional boundary layer flow of an Oldroyd-B fluid is presented. The developed equations are used to discuss the problem of two-dimensional flow in the region of a stagnation point over a stretching sheet. The obtained partial differential equations are reduced to an ordinary differential equation by a suitable transformation. The obtained equation is then solved using a finite difference method. The influence of the pertinent fluid parameters on the velocity is discussed through graphs. The behavior of f (0) is also investigated for the change in parameter values. Our main focus is to discuss the effects of relaxation and retardation time parameters on the velocity components in the x and y directions. In addition to it the skin friction coefficient is evaluated which is a measure of frictional drag at the surface illustrates that the boundary layer thickness decreases due to an increase in the relaxation time constant. The reason is that a higher relaxation time constant give rise to a slower recovery process and as a result the boundary layer thickness grows at a slower rate for a higher value of the relaxation time constant when compared with its lower value. (orig./A.B.)

  4. Nonlinear radiative heat transfer in magnetohydrodynamic (MHD stagnation point flow of nanofluid past a stretching sheet with convective boundary condition

    Directory of Open Access Journals (Sweden)

    Wubshet Ibrahim

    2015-12-01

    Full Text Available Two-dimensional boundary layer flow of nanofluid fluid past a stretching sheet is examined. The paper reveals the effect of non-linear radiative heat transfer on magnetohydrodynamic (MHD stagnation point flow past a stretching sheet with convective heating. Condition of zero normal flux of nanoparticles at the wall for the stretched flow is considered. The nanoparticle fractions on the boundary are considered to be passively controlled. The solution for the velocity, temperature and nanoparticle concentration depends on parameters viz. Prandtl number Pr, velocity ratio parameter A, magnetic parameter M, Lewis number Le, Brownian motion Nb, and the thermophoresis parameter Nt. Moreover, the problem is governed by temperature ratio parameter (Nr=TfT∞ and radiation parameter Rd. Similarity transformation is used to reduce the governing non-linear boundary-value problems into coupled higher order non-linear ordinary differential equation. These equations were numerically solved using the function bvp4c from the matlab software for different values of governing parameters. Numerical results are obtained for velocity, temperature and concentration, as well as the skin friction coefficient and local Nusselt number. The results indicate that the skin friction coefficient Cf increases as the values of magnetic parameter M increase and decreases as the values of velocity ratio parameter A increase. The local Nusselt number −θ′(0 decreases as the values of thermophoresis parameter Nt and radiation parameter Nr increase and it increases as the values of both Biot number Bi and Prandtl number Pr increase. Furthermore, radiation has a positive effect on temperature and concentration profiles.

  5. Surface kinetics for catalytic combustion of hydrogen-air mixtures on platinum at atmospheric pressure in stagnation flows

    Science.gov (United States)

    Ikeda, H.; Sato, J.; Williams, F. A.

    1995-03-01

    Experimental studies of the combustion of premixed hydrogen-air mixtures impinging on the surface of a heated platinum plate at normal atmospheric pressure were performed and employed to draw inferences concerning surface reaction mechanisms and rate parameters applicable under practical conditions of catalytic combustion. Plate and gas temperatures were measured by thermocouples, and concentration profiles of major stable species in the gas were measured by gas-chromatographic analyses of samples withdrawn by quartz probes. In addition, ignition and extinction phenomena were recorded and interpreted with the aid of a heat balance at the surface and a previous flow-field analysis of the stagnation-point boundary layer. From the experimental and theoretical results, conclusions were drawn concerning the surface chemical-kinetic mechanisms and values of the elementary rate parameters that are consistent with the observations. In particular, the activation energy for the surface oxidation step H + OH → H 2O is found to be appreciably less at these high surface coverages than in the low-coverage limit.

  6. Soret and Dufour effects on convective heat and mass transfer in stagnation-point flow towards a shrinking surface

    International Nuclear Information System (INIS)

    Bhattacharyya, Krishnendu; Layek, G C; Seth, G S

    2014-01-01

    A mathematical model is presented to study the Soret and Dufour effects on the convective heat and mass transfer in stagnation-point flow of viscous incompressible fluid towards a shrinking surface. Suitable similarity transformations are used to convert the governing partial differential equations into self-similarity ordinary differential equations that are then numerically solved by shooting method. Dual solutions for temperature and concentration are obtained in the presence of Soret and Dufour effects. Graphical representations of the heat and mass transfer coefficients, the dimensionless thermal and solute profiles for various values of Prandtl number, Lewis number, Soret number and Dufour number are demonstrated. With Soret number the mass transfer coefficient which is related to mass transfer rate increases for both solutions and the heat transfer coefficient (related to heat transfer rate) for both solutions becomes larger with Dufour number. The Prandtl number causes reduction in heat and the mass transfer coefficients and similarly with the Lewis number mass transfer coefficient decreases. Also, double crossing over is found in dual dimensionless temperature profiles for increasing Soret number and in dual dimensionless concentration profiles for the increase in Dufour number. Due to the larger values of Dufour number the thermal boundary layer increases and for Prandtl number increment it decreases; whereas, the solute boundary layer thickness reduces with increasing values of Prandtl number and Lewis number. (paper)

  7. Laboratory studies of stagnating plasma flows with applications to inner solar system and stellar bow shocks

    Science.gov (United States)

    Weber, T. E.; Smith, R. J.; Hsu, S. C.

    2016-10-01

    Supercritical magnetized collisionless shocks are thought to play a dominant role in the overall partition of energy throughout the universe by converting flow kinetic energy to other forms such as thermal and supra-thermal populations, magnetic field enhancement, turbulence, and energetic particles. The Magnetized Shock Experiment (MSX) at LANL creates conditions similar to those of inner solar system and stellar bow shocks by accelerating hot (100s of eV during translation) dense (1022 - 1023 m-3) Field Reversed Configuration (FRC) plasmoids to 100s of km/s; resulting in β 1, collisionless plasma flows with Msonic and MAlfvén 10. The drifting FRC can be made to impinge upon a variety of static obstacles including: a strong mirror or cusp magnetic field (mimicking magnetically excited shocks such as the Earth's bow shock), plasma pileup from a solid obstacle (similar to the bow shocks of Mercury and the Moon), and a neural gas puff (bow shocks of Venus or the comets). Characteristic shock length and time scales that are both large enough to observe yet small enough to fit within the experiment, enabling study of the complex interplay of kinetic and fluid processes that mediate cosmic shocks and can generate non-thermal distributions, produce density and magnetic field enhancements much greater than predicted by fluid theory, and accelerate particles. An overview of the experimental program will be presented, including recent results. This work is supported by the U.S. DOE, Office of Science, Office of Fusion Energy Sciences under Contract No. DE-AC52-06NA25369.

  8. Streamline-based microfluidic device

    Science.gov (United States)

    Tai, Yu-Chong (Inventor); Zheng, Siyang (Inventor); Kasdan, Harvey (Inventor)

    2013-01-01

    The present invention provides a streamline-based device and a method for using the device for continuous separation of particles including cells in biological fluids. The device includes a main microchannel and an array of side microchannels disposed on a substrate. The main microchannel has a plurality of stagnation points with a predetermined geometric design, for example, each of the stagnation points has a predetermined distance from the upstream edge of each of the side microchannels. The particles are separated and collected in the side microchannels.

  9. Analysis Of Convective Plane Stagnation Point Chemically Reactive Mhd Flow Past A Vertical Porous Plate With A Convective Boundary Condition In The Presence Of A Uniform Magnetic Field.

    OpenAIRE

    Adeniyan, A.,

    2013-01-01

    The numerical investigation of a stagnation point boundary layer flow , mass and heat transfer of a steady two dimensional , incompressible , viscous electrically conducting, chemically reacting laminar fluid over a vertical convectively heated , electrically neutral flat plate exposed to a transverse uniform magnetic field has been carried out to examine the influence of the simultaneous presence of the effects of a convective boundary condition, chemical reaction, heat transfer and suctio...

  10. Thermophysical analysis for three-dimensional MHD stagnation-point flow of nano-material influenced by an exponential stretching surface

    Directory of Open Access Journals (Sweden)

    Fiaz Ur Rehman

    2018-03-01

    Full Text Available In the present paper a theoretical investigation is performed to analyze heat and mass transport enhancement of water-based nanofluid for three dimensional (3D MHD stagnation-point flow caused by an exponentially stretched surface. Water is considered as a base fluid. There are three (3 types of nanoparticles considered in this study namely, CuO (Copper oxide, Fe3O4 (Magnetite, and Al2O3 (Alumina are considered along with water. In this problem we invoked the boundary layer phenomena and suitable similarity transformation, as a result our three dimensional non-linear equations of describing current problem are transmuted into nonlinear and non-homogeneous differential equations involving ordinary derivatives. We solved the final equations by applying homotopy analysis technique. Influential outcomes of aggressing parameters involved in this study, effecting profiles of temperature field and velocity are explained in detail. Graphical results of involved parameters appearing in considered nanofluid are presented separately. It is worth mentioning that Skin-friction along x and y-direction is maximum for Copper oxide-water nanofluid and minimum for Alumina-water nanofluid. Result for local Nusselt number is maximum for Copper oxide-water nanofluid and is minimum for magnetite-water nanofluid. Keywords: Heat transfer, Nanofluids, Stagnation-point flow, Three-dimensional flow, Nano particles, Boundary layer

  11. Large eddy simulation of premixed and non-premixed combustion in a Stagnation Point Reverse Flow combustor

    Science.gov (United States)

    Undapalli, Satish

    A new combustor referred to as Stagnation Point Reverse Flow (SPRF) combustor has been developed at Georgia Tech to meet the increasingly stringent emission regulations. The combustor incorporates a novel design to meet the conflicting requirements of low pollution and high stability in both premixed and non-premixed modes. The objective of this thesis work is to perform Large Eddy Simulations (LES) on this lab-scale combustor and elucidate the underlying physics that has resulted in its excellent performance. To achieve this, numerical simulations have been performed in both the premixed and non-premixed combustion modes, and velocity field, species field, entrainment characteristics, flame structure, emissions, and mixing characteristics have been analyzed. Simulations have been carried out first for a non-reactive case to resolve relevant fluid mechanics without heat release by the computational grid. The computed mean and RMS quantities in the non-reacting case compared well with the experimental data. Next, the simulations were extended for the premixed reactive case by employing different sub-grid scale combustion chemistry closures: Eddy Break Up (EBU), Artificially Thickened Flame (TF) and Linear Eddy Mixing (LEM) models. Results from the EBU and TF models exhibit reasonable agreement with the experimental velocity field. However, the computed thermal and species fields have noticeable discrepancies. Only LEM with LES (LEMLES), which is an advanced scalar approach, has been able to accurately predict both the velocity and species fields. Scalar mixing plays an important role in combustion, and this is solved directly at the sub-grid scales in LEM. As a result, LEM accurately predicts the scalar fields. Due to the two way coupling between the super-grid and sub-grid quantities, the velocity predictions also compare very well with the experiments. In other approaches, the sub-grid effects have been either modeled using conventional approaches (EBU) or need

  12. Mixed hybrid finite elements and streamline computation for the potential flow problem

    NARCIS (Netherlands)

    Kaasschieter, E.F.; Huijben, A.J.M.

    1992-01-01

    An important class of problems in mathematical physics involves equations of the form -¿ · (A¿¿) = f. In a variety of problems it is desirable to obtain an accurate approximation of the flow quantity u = -A¿¿. Such an accurate approximation can be determined by the mixed finite element method. In

  13. Solar wind stagnation near comets

    International Nuclear Information System (INIS)

    Galeev, A.A.; Cravens, T.E.; Gombosi, T.I.

    1983-03-01

    The nature of the solar wind flow near comets is examined analytically. In particular, the typical values for the stagnation pressure and magnetic barrier strength are estimated, taking into account the magnetic field line tension and the charge exchange cooling of the mass loaded solar wind. Knowledge of the strength of the magnetic barrier is required in order to determine the location of the contact discontinuity which separates the contaminated solar wind plasma and the outflowing plasma of the cometary ionosphere. (author)

  14. Numerical analysis for MHD thermal and solutal stratified stagnation point flow of Powell-Eyring fluid induced by cylindrical surface with dual convection and heat generation effects

    Science.gov (United States)

    Khalil-Ur-Rehman; Malik, M. Y.; Bilal, S.; Bibi, M.

    The current analysis reports the untapped characteristics of magneto-hydrodynamic dual convection boundary layer stagnation point flow of Powell-Eyring fluid by way of cylindrical surface. Flow exploration is carried out with the combined effects of thermal and solutal stratification. The strength of temperature and concentration adjacent to the cylindrical surface is assumed to be greater than the ambient fluid. Flow conducting mathematically modelled equations are fairly transformed into system of coupled non-linear ordinary differential equations with the aid of suitable transformations. The computations are made against these resultant coupled equations through shooting technique by the support of fifth order Runge-Kutta algorithm. A parametric study is performed to examine the effect logs of various pertinent flow controlling parameters on the velocity, temperature and concentration flow regime. The achieved outcomes are validated by developing comparison with existing published literature. In addition, numerical values of skin friction coefficient and Nusselt number are presented graphically for two different geometries namely, plate and cylinder.

  15. MHD stagnation point flow and heat transfer of a nanofluid over a permeable nonlinear stretching/shrinking sheet with viscous dissipation effect

    Science.gov (United States)

    Jusoh, Rahimah; Nazar, Roslinda

    2018-04-01

    The magnetohydrodynamic (MHD) stagnation point flow and heat transfer of an electrically conducting nanofluid over a nonlinear stretching/shrinking sheet is studied numerically. Mathematical modelling and analysis are attended in the presence of viscous dissipation. Appropriate similarity transformations are used to reduce the boundary layer equations for momentum, energy and concentration into a set of ordinary differential equations. The reduced equations are solved numerically using the built in bvp4c function in Matlab. The numerical and graphical results on the effects of various parameters on the velocity and temperature profiles as well as the skin friction coefficient and the local Nusselt number are analyzed and discussed in this paper. The study discovers the existence of dual solutions for a certain range of the suction parameter. The conducted stability analysis reveals that the first solution is stable and feasible, while the second solution is unstable.

  16. Effects of variable properties on MHD heat and mass transfer flow near a stagnation point towards a stretching sheet in a porous medium with thermal radiation

    Science.gov (United States)

    M. Salem, A.; Rania, Fathy

    2012-05-01

    The effect of variable viscosity and thermal conductivity on steady magnetohydrodynamic (MHD) heat and mass transfer flow of viscous and incompressible fluid near a stagnation point towards a permeable stretching sheet embedded in a porous medium are presented, taking into account thermal radiation and internal heat genberation/absorbtion. The stretching velocity and the ambient fluid velocity are assumed to vary linearly with the distance from the stagnation point. The Rosseland approximation is used to describe the radiative heat flux in the energy equation. The governing fundamental equations are first transformed into a system of ordinary differential equations using a scaling group of transformations and are solved numerically by using the fourth-order Rung—Kutta method with the shooting technique. A comparison with previously published work has been carried out and the results are found to be in good agreement. The results are analyzed for the effect of different physical parameters, such as the variable viscosity and thermal conductivity, the ratio of free stream velocity to stretching velocity, the magnetic field, the porosity, the radiation and suction/injection on the flow, and the heat and mass transfer characteristics. The results indicate that the inclusion of variable viscosity and thermal conductivity into the fluids of light and medium molecular weight is able to change the boundary-layer behavior for all values of the velocity ratio parameter λ except for λ = 1. In addition, the imposition of fluid suction increases both the rate of heat and mass transfer, whereas fluid injection shows the opposite effect.

  17. Effects of variable properties on MHD heat and mass transfer flow near a stagnation point towards a stretching sheet in a porous medium with thermal radiation

    International Nuclear Information System (INIS)

    Salem, A. M.; Fathy, Rania

    2012-01-01

    The effect of variable viscosity and thermal conductivity on steady magnetohydrodynamic (MHD) heat and mass transfer flow of viscous and incompressible fluid near a stagnation point towards a permeable stretching sheet embedded in a porous medium are presented, taking into account thermal radiation and internal heat genberation/absorbtion. The stretching velocity and the ambient fluid velocity are assumed to vary linearly with the distance from the stagnation point. The Rosseland approximation is used to describe the radiative heat flux in the energy equation. The governing fundamental equations are first transformed into a system of ordinary differential equations using a scaling group of transformations and are solved numerically by using the fourth-order Rung—Kutta method with the shooting technique. A comparison with previously published work has been carried out and the results are found to be in good agreement. The results are analyzed for the effect of different physical parameters, such as the variable viscosity and thermal conductivity, the ratio of free stream velocity to stretching velocity, the magnetic field, the porosity, the radiation and suction/injection on the flow, and the heat and mass transfer characteristics. The results indicate that the inclusion of variable viscosity and thermal conductivity into the fluids of light and medium molecular weight is able to change the boundary-layer behavior for all values of the velocity ratio parameter λ except for λ = 1. In addition, the imposition of fluid suction increases both the rate of heat and mass transfer, whereas fluid injection shows the opposite effect. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

  18. Geologic storage of carbon dioxide and enhanced oil recovery. I. Uncertainty quantification employing a streamline based proxy for reservoir flow simulation

    International Nuclear Information System (INIS)

    Kovscek, A.R.; Wang, Y.

    2005-01-01

    Carbon dioxide (CO 2 ) is already injected into a limited class of reservoirs for oil recovery purposes; however, the engineering design question for simultaneous oil recovery and storage of anthropogenic CO 2 is significantly different from that of oil recovery alone. Currently, the volumes of CO 2 injected solely for oil recovery are minimized due to the purchase cost of CO 2 . If and when CO 2 emissions to the atmosphere are managed, it will be necessary to maximize simultaneously both economic oil recovery and the volumes of CO 2 emplaced in oil reservoirs. This process is coined 'cooptimization'. This paper proposes a work flow for cooptimization of oil recovery and geologic CO 2 storage. An important component of the work flow is the assessment of uncertainty in predictions of performance. Typical methods for quantifying uncertainty employ exhaustive flow simulation of multiple stochastic realizations of the geologic architecture of a reservoir. Such approaches are computationally intensive and thereby time consuming. An analytic streamline based proxy for full reservoir simulation is proposed and tested. Streamline trajectories represent the three-dimensional velocity field during multiphase flow in porous media and so are useful for quantifying the similarity and differences among various reservoir models. The proxy allows rational selection of a representative subset of equi-probable reservoir models that encompass uncertainty with respect to true reservoir geology. The streamline approach is demonstrated to be thorough and rapid

  19. RELAP4 stagnation properties option

    International Nuclear Information System (INIS)

    DeYoung, T.L.

    1979-01-01

    The stagnation properties option in RELAP4/MOD6 was completely reviewed, from theoretical foundation to code application. The result of this investigation was the identification of a fundamental mismatch between the essentially homogeneous, equilibrium-based, RELAP4 code and the nonhomogeneous and/or nonequilibrium critical flow models imposed on the code. By continuously monitoring fluid Mach numbers and adjusting flow areas such that sonic velocity was never exceeded, the mismatch could be accommodated. This approach was implemented, found to work correctly, and will be incorporated into the MOD7 version of the code

  20. Numerical investigation on MHD micropolar fluid flow toward a stagnation point on a vertical surface with heat source and chemical reaction

    Directory of Open Access Journals (Sweden)

    S. Baag

    2017-01-01

    Full Text Available In this paper, the steady magnetohydrodynamic (MHD mixed convection stagnation point flow of an incompressible and electrically conducting micropolar fluid past a vertical flat plate is investigated. The effects of induced magnetic field, heat generation/absorption and chemical reaction have been taken into account during the present study. Numerical solutions are obtained by using the Runge–Kutta fourth order scheme with shooting technique. The skin friction and rate of heat and mass transfer at the bounding surface are also calculated. The generality of the present study is assured of by discussing the works of Ramachandran et al. (1988, Lok et al. (2005 and Ishak et al. (2008 as particular cases. It is interesting to note that the results of the previous authors are in good agreement with the results of the present study tabulated which is evident from the tabular values. Further, the novelty of the present analysis is to account for the effects of first order chemical reaction in a flow of reactive diffusing species in the presence of heat source/sink. The discussion of the present study takes care of both assisting and opposing flows. From the computational aspect, it is remarked that results of finite difference (Ishak et al. (2008 and Runge–Kutta associated with shooting technique (present method yield same numerical results with a certain degree of accuracy. It is important to note that the thermal buoyancy parameter in opposing flow acts as a controlling parameter to prevent back flow. Diffusion of lighter foreign species, suitable for initiating a destructive reaction, is a suggestive measure for reducing skin friction.

  1. Mixed convection stagnation-point flow of nanofluids over a stretching/shrinking sheet in a porous medium with internal heat generation/absorption

    Directory of Open Access Journals (Sweden)

    Dulal Pal

    2015-05-01

    Full Text Available In this paper, we analyzed the buoyancy-driven radiative non-isothermal heat transfer in a nanofluid stagnation-point flow over a stretching/shrinking sheet embedded in a porous medium.The effects of thermal radiation and internal heat generation/absorption along with suction/injection at the boundary are also considered. Three different types of nanofluids, namely the Copper-water, the Alumina-water and the Titanium dioxide water are considered. The resulting coupled nonlinear differential equations are solved numerically by a fifth-order Runge-Kutta-Fehlberg integration scheme with a shooting technique. A good agreement is found between the present numerical results and the available results in the literature for some special cases. The effects of the physical parameters on the flow and temperature characteristics are presented through tables and graphs, and the salient features are discussed. The results obtained reveal many interesting behaviors that warrant further study on the heat transfer enhancement due to the nanofluids.

  2. Thermophysical analysis for three-dimensional MHD stagnation-point flow of nano-material influenced by an exponential stretching surface

    Science.gov (United States)

    Ur Rehman, Fiaz; Nadeem, Sohail; Ur Rehman, Hafeez; Ul Haq, Rizwan

    2018-03-01

    In the present paper a theoretical investigation is performed to analyze heat and mass transport enhancement of water-based nanofluid for three dimensional (3D) MHD stagnation-point flow caused by an exponentially stretched surface. Water is considered as a base fluid. There are three (3) types of nanoparticles considered in this study namely, CuO (Copper oxide), Fe3O4 (Magnetite), and Al2O3 (Alumina) are considered along with water. In this problem we invoked the boundary layer phenomena and suitable similarity transformation, as a result our three dimensional non-linear equations of describing current problem are transmuted into nonlinear and non-homogeneous differential equations involving ordinary derivatives. We solved the final equations by applying homotopy analysis technique. Influential outcomes of aggressing parameters involved in this study, effecting profiles of temperature field and velocity are explained in detail. Graphical results of involved parameters appearing in considered nanofluid are presented separately. It is worth mentioning that Skin-friction along x and y-direction is maximum for Copper oxide-water nanofluid and minimum for Alumina-water nanofluid. Result for local Nusselt number is maximum for Copper oxide-water nanofluid and is minimum for magnetite-water nanofluid.

  3. The unsteady flow of a nanofluid in the stagnation point region of a time-dependent rotating sphere

    Directory of Open Access Journals (Sweden)

    Malvandi Amir

    2015-01-01

    Full Text Available This paper deals with the unsteady boundary layer flow and heat transfer of nanofluid over a time-dependent rotating sphere where the free stream velocity varies continuously with time. The boundary layer equations were normalized via similarity variables and solved numerically. Best accuracy of the results has been obtained for regular fluid with previous studies. The nanofluid is treated as a two-component mixture (base fluid+nanoparticles that incorporates the effects of Brownian diffusion and thermophoresis simultaneously as the two most important mechanisms of slip velocity in laminar flows. Our outcomes indicated that as A and λ increase, surface shear stresses, heat transfer and concentration rates, climb up. Also, Increasing the thermophoresis Nt is found to decrease in the both values of heat transfer and concentration rates. This decrease supresses for higher thermophoresis number. In addition, it was observed that unlike the heat transfer rate, a rise in Brownian motion Nb, leads to an increase in concentration rate.

  4. Impacts of variable thermal conductivity on stagnation point boundary layer flow past a Riga plate with variable thickness using generalized Fourier's law

    Science.gov (United States)

    Shah, S.; Hussain, S.; Sagheer, M.

    2018-06-01

    This article explores the problem of two-dimensional, laminar, steady and boundary layer stagnation point slip flow over a Riga plate. The incompressible upper-convected Maxwell fluid has been considered as a rheological fluid model. The heat transfer characteristics are investigated with generalized Fourier's law. The fluid thermal conductivity is assumed to be temperature dependent in this study. A system of partial differential equations governing the flow of an upper-convected Maxwell fluid, heat and mass transfer using generalized Fourier's law is developed. The main objective of the article is to inspect the impacts of pertinent physical parameters such as the stretching ratio parameter (0 ⩽ A ⩽ 0.3) , Deborah number (0 ⩽ β ⩽ 0.6) , thermal relaxation parameter (0 ⩽ γ ⩽ 0.5) , wall thickness parameter (0.1 ⩽ α ⩽ 3.5) , slip parameter (0 ⩽ R ⩽ 1.5) , thermal conductivity parameter (0.1 ⩽ δ ⩽ 1.0) and modified Hartmann number (0 ⩽ Q ⩽ 3) on the velocity and temperature profiles. Suitable local similarity transformations have been used to get a system of non-linear ODEs from the governing PDEs. The numerical solutions for the dimensionless velocity and temperature distributions have been achieved by employing an effective numerical method called the shooting method. It is seen that the velocity profile shows the reduction in the velocity for the higher values of viscoelastic parameter and the thermal relaxation parameter. In addition, to enhance the reliability at the maximum level of the obtained numerical results by shooting method, a MATLAB built-in solver bvp4c has also been utilized.

  5. Flow topology adjacent to a fast moving contact line

    International Nuclear Information System (INIS)

    Royon, A.; Ehrhard, P.

    2001-10-01

    Coating processes are commonly used in industry. In the present report the physical mechanisms involved in such wetting phenomena are investigated (a) by a numerical and (b) by an experimental approach in a plane section perpendicular to the contact line. The problem relates to a tape plunging vertically into a pool of two immiscible fluids. The equations and boundary conditions describing the problem are treated in non-dimensional form. Several simplifications are introduced to obtain a first approximative solution to the problem. The relevant parameters are the viscosity ratio V V , the density ratio D V and the Reynolds number of the heavy fluid, Re 1 . By a variation of the viscosity ratio or of the Reynolds number we demonstrate the existence of three typical flow structures: (1) stagnation point streamline in the light fluid, (2) stagnation point streamline in the heavy fluid or (3) transition flow with stagnation point streamlines in both fluids. The structure changes continuously from a complex flow in the light fluid to a complex flow in the heavy fluid by an increase of the viscosity ratio or by an increase of the Reynolds number in the heavy fluid. The mechanisms of the transitions, involving a thickening of the viscous boundary layer and inertial effects, are discussed in detail. The solution only weakly depends on the density ratio. In the experiment a PE-tape plunges into a pool of (a) silicone oil M1000 and air, (b) water and silicone oil M50 or (c) water and silicone oil M10. The experimental investigations confirm the existence of the two limit structures, namely a stagnation point streamline in air for the combination (a) or a stagnation point streamline in water for the combination (b). Even the transition from one flow structure to the other is observed with an increase of the Reynolds number for the combination (c). (orig.)

  6. Public debt, secular stagnation and functional finance

    DEFF Research Database (Denmark)

    Skott, Peter

    2016-01-01

    Fiscal policy and public debt may be required to maintain full employment and avoid secular stagnation. This conclusion emerges from a range of different models, including OLG specifications and stock-flow consistent (post-) Keynesian models. One of the determinants of the required long-run debt ...

  7. A Streamline-Upwind Petrov-Galerkin Finite Element Scheme for Non-Ionized Hypersonic Flows in Thermochemical Nonequilibrium

    Science.gov (United States)

    Kirk, Benjamin S.; Bova, Stephen W.; Bond, Ryan B.

    2011-01-01

    Presentation topics include background and motivation; physical modeling including governing equations and thermochemistry; finite element formulation; results of inviscid thermal nonequilibrium chemically reacting flow and viscous thermal equilibrium chemical reacting flow; and near-term effort.

  8. Secular stagnation or stagnation policy? Steindl after Summers

    Directory of Open Access Journals (Sweden)

    Eckhard Hein

    2016-03-01

    Full Text Available The debate on secular stagnation suffers from vagueness and several shortcomings, which affect its economic policy implications. In this work we provide an alternative view on the advanced economies’ tendencies to stagnation, based on Josef Steindl’s contributions. Steindl’s pioneering 1952 book in particular is not prone to several problems that affect the current debate on secular stagnation. It does not rely on the dubious notion of an equilibrium real interest rate as the equilibrating force of saving and investment at full employment levels. Rather, it is based on the notion that modern capitalist economies face aggregate demand constraints, and that saving adjusts to investment through income growth and changes in capacity utilisation in the long run. Steindl’s treatment allows for potential growth to become endogenous to actual demand, and it seriously considers the role of institutions and power relationships for long-run growth. In illustrating Steindl’s contributions on this topic, the article presents an original model synthetizing the main points in particular concerning long run growth and stagnation. JEL codes: B22, E11, E12, E65, O11

  9. Construction and analysis of compressible flow calculation algorithms

    International Nuclear Information System (INIS)

    Desideri, Jean-Antoine

    1993-01-01

    The aim of this study is to give a theoretical rationale of a 'paradox' related to the behavior at the stagnation point of some numerical solutions obtained by conventional methods for Eulerian non-equilibrium flows. This 'paradox' concerns the relationship between the solutions given by equilibrium and non-equilibrium models and was raised by several experts during the 'Workshop on Hypersonic Flows for Reentry Problems, Part 1. Antibes 1990'. In the first part, we show that equilibrium conditions are reached at the stagnation point and we analyse the sensitivity of these equilibrium conditions to the flow variables. In the second part, we develop an analysis of the behavior of the mathematical solution to an Eulerian non-equilibrium flow in the vicinity of the stagnation point, which gives an explanation to the described 'paradox'. Then, a numerical procedure, integrating the species convection equations projected on the stagnation point streamline in a Lagrangian time approach, gives a numerical support to the theoretical predictions. We also propose two numerical integration procedures, that allow us to recompute, starting from the equilibrium conditions at the stagnation point, the flow characteristics at the body. The validity limits of these procedures are discussed and the results obtained for a Workshop test-case are compared with the results given by several contributors. Finally, we survey briefly the influence of the local behavior of the solution on the coupling technique to a boundary layer calculation. (author) [fr

  10. Stability of stagnation via an expanding accretion shock wave

    International Nuclear Information System (INIS)

    Velikovich, A. L.; Giuliani, J. L.; Murakami, M.; Taylor, B. D.; Zalesak, S. T.; Iwamoto, Y.

    2016-01-01

    Stagnation of a cold plasma streaming to the center or axis of symmetry via an expanding accretion shock wave is ubiquitous in inertial confinement fusion (ICF) and high-energy-density plasma physics, the examples ranging from plasma flows in x-ray-generating Z pinches [Maron et al., Phys. Rev. Lett. 111, 035001 (2013)] to the experiments in support of the recently suggested concept of impact ignition in ICF [Azechi et al., Phys. Rev. Lett. 102, 235002 (2009); Murakami et al., Nucl. Fusion 54, 054007 (2014)]. Some experimental evidence indicates that stagnation via an expanding shock wave is stable, but its stability has never been studied theoretically. We present such analysis for the stagnation that does not involve a rarefaction wave behind the expanding shock front and is described by the classic ideal-gas Noh solution in spherical and cylindrical geometry. In either case, the stagnated flow has been demonstrated to be stable, initial perturbations exhibiting a power-law, oscillatory or monotonic, decay with time for all the eigenmodes. This conclusion has been supported by our simulations done both on a Cartesian grid and on a curvilinear grid in spherical coordinates. Dispersion equation determining the eigenvalues of the problem and explicit formulas for the eigenfunction profiles corresponding to these eigenvalues are presented, making it possible to use the theory for hydrocode verification in two and three dimensions.

  11. Stability of stagnation via an expanding accretion shock wave

    Energy Technology Data Exchange (ETDEWEB)

    Velikovich, A. L.; Giuliani, J. L. [Plasma Physics Division, Naval Research Laboratory, Washington, DC 20375 (United States); Murakami, M. [Institute of Laser Engineering, Osaka University, Osaka 565-0871 (Japan); Taylor, B. D. [Laboratory for Computational Physics and Fluid Dynamics, Naval Research Laboratory, Washington, DC 20375 (United States); Zalesak, S. T. [Berkeley Research Associates, Beltsville, Maryland 20705 (United States); Iwamoto, Y. [Ehime University, Matsuyama, Ehime Pref. 790-8577 (Japan)

    2016-05-15

    Stagnation of a cold plasma streaming to the center or axis of symmetry via an expanding accretion shock wave is ubiquitous in inertial confinement fusion (ICF) and high-energy-density plasma physics, the examples ranging from plasma flows in x-ray-generating Z pinches [Maron et al., Phys. Rev. Lett. 111, 035001 (2013)] to the experiments in support of the recently suggested concept of impact ignition in ICF [Azechi et al., Phys. Rev. Lett. 102, 235002 (2009); Murakami et al., Nucl. Fusion 54, 054007 (2014)]. Some experimental evidence indicates that stagnation via an expanding shock wave is stable, but its stability has never been studied theoretically. We present such analysis for the stagnation that does not involve a rarefaction wave behind the expanding shock front and is described by the classic ideal-gas Noh solution in spherical and cylindrical geometry. In either case, the stagnated flow has been demonstrated to be stable, initial perturbations exhibiting a power-law, oscillatory or monotonic, decay with time for all the eigenmodes. This conclusion has been supported by our simulations done both on a Cartesian grid and on a curvilinear grid in spherical coordinates. Dispersion equation determining the eigenvalues of the problem and explicit formulas for the eigenfunction profiles corresponding to these eigenvalues are presented, making it possible to use the theory for hydrocode verification in two and three dimensions.

  12. Stability of stagnation via an expanding accretion shock wave

    Science.gov (United States)

    Velikovich, A. L.; Murakami, M.; Taylor, B. D.; Giuliani, J. L.; Zalesak, S. T.; Iwamoto, Y.

    2016-05-01

    Stagnation of a cold plasma streaming to the center or axis of symmetry via an expanding accretion shock wave is ubiquitous in inertial confinement fusion (ICF) and high-energy-density plasma physics, the examples ranging from plasma flows in x-ray-generating Z pinches [Maron et al., Phys. Rev. Lett. 111, 035001 (2013)] to the experiments in support of the recently suggested concept of impact ignition in ICF [Azechi et al., Phys. Rev. Lett. 102, 235002 (2009); Murakami et al., Nucl. Fusion 54, 054007 (2014)]. Some experimental evidence indicates that stagnation via an expanding shock wave is stable, but its stability has never been studied theoretically. We present such analysis for the stagnation that does not involve a rarefaction wave behind the expanding shock front and is described by the classic ideal-gas Noh solution in spherical and cylindrical geometry. In either case, the stagnated flow has been demonstrated to be stable, initial perturbations exhibiting a power-law, oscillatory or monotonic, decay with time for all the eigenmodes. This conclusion has been supported by our simulations done both on a Cartesian grid and on a curvilinear grid in spherical coordinates. Dispersion equation determining the eigenvalues of the problem and explicit formulas for the eigenfunction profiles corresponding to these eigenvalues are presented, making it possible to use the theory for hydrocode verification in two and three dimensions.

  13. Reference Structures: Stagnation, Progress, and Future Challenges.

    Science.gov (United States)

    Greenberg, Jane

    1997-01-01

    Assesses the current state of reference structures in online public access catalogs (OPACs) in a framework defined by stagnation, progress, and future challenges. Outlines six areas for reference structure development. Twenty figures provide illustrations. (AEF)

  14. Streamline segment statistics of premixed flames with nonunity Lewis numbers

    Science.gov (United States)

    Chakraborty, Nilanjan; Wang, Lipo; Klein, Markus

    2014-03-01

    The interaction of flame and surrounding fluid motion is of central importance in the fundamental understanding of turbulent combustion. It is demonstrated here that this interaction can be represented using streamline segment analysis, which was previously applied in nonreactive turbulence. The present work focuses on the effects of the global Lewis number (Le) on streamline segment statistics in premixed flames in the thin-reaction-zones regime. A direct numerical simulation database of freely propagating thin-reaction-zones regime flames with Le ranging from 0.34 to 1.2 is used to demonstrate that Le has significant influences on the characteristic features of the streamline segment, such as the curve length, the difference in the velocity magnitude at two extremal points, and their correlations with the local flame curvature. The strengthenings of the dilatation rate, flame normal acceleration, and flame-generated turbulence with decreasing Le are principally responsible for these observed effects. An expression for the probability density function (pdf) of the streamline segment length, originally developed for nonreacting turbulent flows, captures the qualitative behavior for turbulent premixed flames in the thin-reaction-zones regime for a wide range of Le values. The joint pdfs between the streamline length and the difference in the velocity magnitude at two extremal points for both unweighted and density-weighted velocity vectors are analyzed and compared. Detailed explanations are provided for the observed differences in the topological behaviors of the streamline segment in response to the global Le.

  15. Aggregate demand, functional finance and secular stagnation

    DEFF Research Database (Denmark)

    Skott, Peter

    2016-01-01

    This paper makes three main points. Fiscal policy, first, may be needed in the long run to maintain full employment and avoid secular stagnation. If fiscal policy is used in this way, second, the long-run debt ratio depends (i) inversely on the rate of growth, (ii) inversely on government consump...

  16. Technological Progress, Globalization, and Secular Stagnation

    Directory of Open Access Journals (Sweden)

    Popović Milenko

    2018-01-01

    Full Text Available After the 2008 crisis, despite economic recovery that started in 2009, the world economy has experienced a downward shift of its growth path and a consequent decline. As shown at the beginning of this paper, this shift and growth rate stagnation are totally attributable to the economic dynamics in developed economies, the USA and the EU. Explanations of this phenomenon can be divided into two large groups: explanations that belong to the demand side and those that belong to the supply side. The aim of this paper is to give a critical survey of the most important explanations for the ongoing growth stagnation in developed countries and consequently in the entire world economy. This ongoing prolonged stagnation can only be explained by looking at both, the demand and supply sides of the explanation, and particularly by taking a closer look at the interaction between aggregate demand and aggregate supply. In other words, secular stagnation manifests itself as a problem of the limitation of long run growth of aggregate demand. However, in order to explain the causes of those demand limitations, we have to undertake a careful analysis of the supply side dynamics, especially the dynamics of innovations, which bring us to circular and cumulative causation. In order to explain the numerous consequences of this stagnation and to solve some important puzzles, like the productivity paradox for example, a special emphasis is given to the analysis of deindustrialization and the consequent strange reoccurrence of a dual economy within most developed countries during the period of the IT revolution and hyper-globalization. It will also be shown that this new dual economy presents serious limitations for further technological advancement and economic development, quite contrary to the old dualism which contributed to an acceleration of economic growth.

  17. Dividing Streamline Formation Channel Confluences by Physical Modeling

    Directory of Open Access Journals (Sweden)

    Minarni Nur Trilita

    2010-02-01

    Full Text Available Confluence channels are often found in open channel network system and is the most important element. The incoming flow from the branch channel to the main cause various forms and cause vortex flow. Phenomenon can cause erosion of the side wall of the channel, the bed channel scour and sedimentation in the downstream confluence channel. To control these problems needed research into the current width of the branch channel. The incoming flow from the branch channel to the main channel flow bounded by a line distributors (dividing streamline. In this paper, the wide dividing streamline observed in the laboratory using a physical model of two open channels, a square that formed an angle of 30º. Observations were made with a variety of flow coming from each channel. The results obtained in the laboratory observation that the width of dividing streamline flow is influenced by the discharge ratio between the channel branch with the main channel. While the results of a comparison with previous studies showing that the observation in the laboratory is smaller than the results of previous research.

  18. Flow Characteristics of Rectangular Underexpanded Impinging Jets

    Institute of Scientific and Technical Information of China (English)

    Minoru YAGA; Yoshio KINJO; Masumi TAMASHIRO; Kenyu OYAKAWA

    2006-01-01

    In this paper, the flow fields of underexpanded impinging jet issued from rectangular nozzles of aspect ratio 1,3 and 5 are numerically and experimentally studied. Two dimensional temperature and pressure distributions are measured by using infrared camera and the combination of a pressure scanning device and a stepping motor, respectively. The variation of the stagnation pressure on the impinging plate reveals that a hystcretic phenomenon exists during the increasing and decreasing of the pressure ratio for the aspect ratio of 3.0 and 5.0. It is also found that the nozzle of aspect ratio 1.0 caused the largest total pressure loss pc/p0 = 0.27 at the pressure ratio of p0/pb, = 6.5, where pc is the stagnation center pressure on the wall, p0 the upstream stagnation pressure, pb the ambient pressure. The other two nozzles showed that the pressure loss pc / p0=0.52 and 0.55 were achieved by the nozzles of the aspect ratio 3,0 and 5.0, respectively. The comparison between the calculations and experiments is fairly good, showing the three dimensional streamlines and structures of the shock waves in the jets. However, the hysteresis of the pressure variations observed in the experiments between the pressure ratio of 3.5 and 4.5 cannot be confirmed in the calculations.

  19. Demographic stagnation and decline in Spain: A cause for concern?

    Directory of Open Access Journals (Sweden)

    Serrano-Martínez José-María

    2018-03-01

    Full Text Available For years, the Spanish population has been rapidly ageing, showing signs of atony and stagnation. Between 1996 and 2007, in a phase of economic growth, the entry of foreign immigrants drove a global increase in population. But after the economic recession migratory flows show negative net balances. Our objective is to explain and confirm the demographic regression suffered by Spain. We are also interested in showing how the recent and intense immigration process has failed to generate significant changes in natural demographic characteristics and trends. National censuses, published by the National Institute of Statistics (INE, are our main source of demographic data. The analysis of the most recent relevant scientific literature has allowed us to compare opinions and discuss results. The data confirm an uncertain and worrying future for the Spanish population.

  20. Streamlining Smart Meter Data Analytics

    DEFF Research Database (Denmark)

    Liu, Xiufeng; Nielsen, Per Sieverts

    2015-01-01

    of the so-called big data possible. This can improve energy management, e.g., help utilities improve the management of energy and services, and help customers save money. As this regard, the paper focuses on building an innovative software solution to streamline smart meter data analytic, aiming at dealing......Today smart meters are increasingly used in worldwide. Smart meters are the advanced meters capable of measuring customer energy consumption at a fine-grained time interval, e.g., every 15 minutes. The data are very sizable, and might be from different sources, along with the other social......-economic metrics such as the geographic information of meters, the information about users and their property, geographic location and others, which make the data management very complex. On the other hand, data-mining and the emerging cloud computing technologies make the collection, management, and analysis...

  1. Damage Detection with Streamlined Structural Health Monitoring Data

    OpenAIRE

    Li, Jian; Deng, Jun; Xie, Weizhi

    2015-01-01

    The huge amounts of sensor data generated by large scale sensor networks in on-line structural health monitoring (SHM) systems often overwhelms the systems’ capacity for data transmission and analysis. This paper presents a new concept for an integrated SHM system in which a streamlined data flow is used as a unifying thread to integrate the individual components of on-line SHM systems. Such an integrated SHM system has a few desirable functionalities including embedded sensor data compressio...

  2. Energy-political stagnation or innovation

    International Nuclear Information System (INIS)

    Kitschelt, H.

    1982-01-01

    The author discusses the enquete report 1980. He makes an inventory for a political and sociological interpretation of the interim report between meaningful innovation and political insignificance as well as intellectual stagnation. The report is considered as an indicator for the transformation of the energy-political arena in the Federal Republic of Germany over the last years. ''Stagnation'' or ''innovation'' of the argumentation patterns in the report of the enquete commission relate to the question whether the analyses in that document are rather a brake or a motor to a shift of political perspectives in energy policy. A progress can be seen in the report regarding political debate about energy-options in the semi-official political spectrum of the Federal Republic of Germany, in as far as differring options of energy-political development are being acknowledged for the first time. At the same time, debate inside the commission directs the attention to issues of institutional policy in the energy sector. Considering the fights within the commission before the report was agreed on, it seems doubtful if its proposals for compromise will prove a sound political basis. The tensions inside the commission are just a first sign of the power conflicts due above all if the recommendations for energy conservation are intransigently carried out. (orig./HSCH) [de

  3. Joint statistics and conditional mean strain rates of streamline segments

    International Nuclear Information System (INIS)

    Schaefer, P; Gampert, M; Peters, N

    2013-01-01

    Based on four different direct numerical simulations of turbulent flows with Taylor-based Reynolds numbers ranging from Re λ = 50 to 300 among which are two homogeneous isotropic decaying, one forced and one homogeneous shear flow, streamlines are identified and the obtained space curves are parameterized with the pseudo-time as well as the arclength. Based on local extrema of the absolute value of the velocity along the streamlines, the latter are partitioned into segments following Wang (2010 J. Fluid Mech. 648 183–203). Streamline segments are then statistically analyzed based on both parameterizations using the joint probability density function of the pseudo-time lag τ (arclength l, respectively) between and the velocity difference Δu at the extrema: P(τ,Δu), (P(l,Δu)). We distinguish positive and negative streamline segments depending on the sign of the velocity difference Δu. Differences as well as similarities in the statistical description for both parameterizations are discussed. In particular, it turns out that the normalized probability distribution functions (pdfs) (of both parameterizations) of the length of positive, negative and all segments assume a universal shape for all Reynolds numbers and flow types and are well described by a model derived in Schaefer P et al (2012 Phys. Fluids 24 045104). Particular attention is given to the conditional mean velocity difference at the ending points of the segments, which can be understood as a first-order structure function in the context of streamline segment analysis. It determines to a large extent the stretching (compression) of positive (negative) streamline segments and corresponds to the convective velocity in phase space in the transport model equation for the pdf. While based on the random sweeping hypothesis a scaling ∝ (u rms ετ) 1/3 is found for the parameterization based on the pseudo-time, the parameterization with the arclength l yields a much larger than expected l 1/3 scaling. A

  4. Stream-lined Gating Systems with Improved Yield - Dimensioning and Experimental Validation

    DEFF Research Database (Denmark)

    Tiedje, Niels Skat; Skov-Hansen, Søren Peter

    the two types of lay-outs are cast in production. It is shown that flow in the stream-lined lay-out is well controlled and that the quality of the castings is as at least equal to that of castings produced with a traditional lay-out. Further, the yield is improved by 4 % relative to a traditional lay-out.......The paper describes how a stream-lined gating system where the melt is confined and controlled during filling can be designed. Commercial numerical modelling software has been used to compare the stream-lined design with a traditional gating system. These results are confirmed by experiments where...

  5. Orality disorders in melancholia: acedia as stagnation

    Directory of Open Access Journals (Sweden)

    Ana Cecília Magtaz

    2012-09-01

    Full Text Available In this article valuable contributions by Lasègue, Freud and Abraham are discussed, as they are all indispensible to the understanding of orality disorders in melancholia. Although none of the above authors used the exact term "orality disorders," their understandings of both hysteria and melancholia are important in the debate surrounding the clinical treatment of these difficulties. Sadness is a common denominator for the authors, but contributions on acedia, the "noonday demon" mentioned by Agamben, are also important. Acedia is defined as stagnation, a desperate lack of vigor when faced with a wearying and demanding situation. Those who suffer from chronic acedia feel great inertia and are unable to envision a future. They see their creativity wane away, especially due to the painful isolation caused by what might be called anguished sadness - a denial of sadness through manic action.

  6. ACHP | News | ACHP Issues Program Comment to Streamline Communication

    Science.gov (United States)

    Program Comment to Streamline Communication Facilities Construction and Modification ACHP Issues Program Comment to Streamline Communication Facilities Construction and Modification The Advisory Council on

  7. Accelerated Logistics: Streamlining the Army's Supply Chain

    National Research Council Canada - National Science Library

    Wang, Mark

    2000-01-01

    ...) initiative, the Army has dramatically streamlined its supply chain, cutting order and ship times for repair parts by nearly two-thirds nationwide and over 75 percent at several of the major Forces Command (FORSCOM) installations...

  8. Creating customer value by streamlining business processes.

    Science.gov (United States)

    Vantrappen, H

    1992-02-01

    Much of the strategic preoccupation of senior managers in the 1990s is focusing on the creation of customer value. Companies are seeking competitive advantage by streamlining the three processes through which they interact with their customers: product creation, order handling and service assurance. 'Micro-strategy' is a term which has been coined for the trade-offs and decisions on where and how to streamline these three processes. The article discusses micro-strategies applied by successful companies.

  9. Adhesion of leukocytes under oscillating stagnation point conditions: a numerical study.

    Science.gov (United States)

    Walker, P G; Alshorman, A A; Westwood, S; David, T

    2002-01-01

    Leukocyte recruitment from blood to the endothelium plays an important role in atherosclerotic plaque formation. Cells show a primary and secondary adhesive process with primary bonds responsible for capture and rolling and secondary bonds for arrest. Our objective was to investigate the role played by this process on the adhesion of leukocytes in complex flow. Cells were modelled as rigid spheres with spring like adhesion molecules which formed bonds with endothelial receptors. Models of bond kinetics and Newton's laws of motion were solved numerically to determine cell motion. Fluid force was obtained from the local shear rate obtained from a CFD simulation of the flow over a backward facing step.In stagnation point flow the shear rate near the stagnation point has a large gradient such that adherent cells in this region roll to a high shear region preventing permanent adhesion. This is enhanced if a small time dependent perturbation is imposed upon the stagnation point. For lower shear rates the cell rolling velocity may be such that secondary bonds have time to form. These bonds resist the lower fluid forces and consequently there is a relatively large permanent adhesion region.

  10. Industrial Compositional Streamline Simulation for Efficient and Accurate Prediction of Gas Injection and WAG Processes

    Energy Technology Data Exchange (ETDEWEB)

    Margot Gerritsen

    2008-10-31

    Gas-injection processes are widely and increasingly used for enhanced oil recovery (EOR). In the United States, for example, EOR production by gas injection accounts for approximately 45% of total EOR production and has tripled since 1986. The understanding of the multiphase, multicomponent flow taking place in any displacement process is essential for successful design of gas-injection projects. Due to complex reservoir geometry, reservoir fluid properties and phase behavior, the design of accurate and efficient numerical simulations for the multiphase, multicomponent flow governing these processes is nontrivial. In this work, we developed, implemented and tested a streamline based solver for gas injection processes that is computationally very attractive: as compared to traditional Eulerian solvers in use by industry it computes solutions with a computational speed orders of magnitude higher and a comparable accuracy provided that cross-flow effects do not dominate. We contributed to the development of compositional streamline solvers in three significant ways: improvement of the overall framework allowing improved streamline coverage and partial streamline tracing, amongst others; parallelization of the streamline code, which significantly improves wall clock time; and development of new compositional solvers that can be implemented along streamlines as well as in existing Eulerian codes used by industry. We designed several novel ideas in the streamline framework. First, we developed an adaptive streamline coverage algorithm. Adding streamlines locally can reduce computational costs by concentrating computational efforts where needed, and reduce mapping errors. Adapting streamline coverage effectively controls mass balance errors that mostly result from the mapping from streamlines to pressure grid. We also introduced the concept of partial streamlines: streamlines that do not necessarily start and/or end at wells. This allows more efficient coverage and avoids

  11. Impact assessment: Eroding benefits through streamlining?

    Energy Technology Data Exchange (ETDEWEB)

    Bond, Alan, E-mail: alan.bond@uea.ac.uk [School of Environmental Sciences, University of East Anglia (United Kingdom); School of Geo and Spatial Sciences, North-West University (South Africa); Pope, Jenny, E-mail: jenny@integral-sustainability.net [Integral Sustainability (Australia); Curtin University Sustainability Policy Institute (Australia); Morrison-Saunders, Angus, E-mail: A.Morrison-Saunders@murdoch.edu.au [School of Geo and Spatial Sciences, North-West University (South Africa); Environmental Science, Murdoch University (Australia); Retief, Francois, E-mail: francois.retief@nwu.ac.za [School of Geo and Spatial Sciences, North-West University (South Africa); Gunn, Jill A.E., E-mail: jill.gunn@usask.ca [Department of Geography and Planning and School of Environment and Sustainability, University of Saskatchewan (Canada)

    2014-02-15

    This paper argues that Governments have sought to streamline impact assessment in recent years (defined as the last five years) to counter concerns over the costs and potential for delays to economic development. We hypothesise that this has had some adverse consequences on the benefits that subsequently accrue from the assessments. This hypothesis is tested using a framework developed from arguments for the benefits brought by Environmental Impact Assessment made in 1982 in the face of the UK Government opposition to its implementation in a time of economic recession. The particular benefits investigated are ‘consistency and fairness’, ‘early warning’, ‘environment and development’, and ‘public involvement’. Canada, South Africa, the United Kingdom and Western Australia are the jurisdictions tested using this framework. The conclusions indicate that significant streamlining has been undertaken which has had direct adverse effects on some of the benefits that impact assessment should deliver, particularly in Canada and the UK. The research has not examined whether streamlining has had implications for the effectiveness of impact assessment, but the causal link between streamlining and benefits does sound warning bells that merit further investigation. -- Highlights: • Investigation of the extent to which government has streamlined IA. • Evaluation framework was developed based on benefits of impact assessment. • Canada, South Africa, the United Kingdom, and Western Australia were examined. • Trajectory in last five years is attrition of benefits of impact assessment.

  12. Impact assessment: Eroding benefits through streamlining?

    International Nuclear Information System (INIS)

    Bond, Alan; Pope, Jenny; Morrison-Saunders, Angus; Retief, Francois; Gunn, Jill A.E.

    2014-01-01

    This paper argues that Governments have sought to streamline impact assessment in recent years (defined as the last five years) to counter concerns over the costs and potential for delays to economic development. We hypothesise that this has had some adverse consequences on the benefits that subsequently accrue from the assessments. This hypothesis is tested using a framework developed from arguments for the benefits brought by Environmental Impact Assessment made in 1982 in the face of the UK Government opposition to its implementation in a time of economic recession. The particular benefits investigated are ‘consistency and fairness’, ‘early warning’, ‘environment and development’, and ‘public involvement’. Canada, South Africa, the United Kingdom and Western Australia are the jurisdictions tested using this framework. The conclusions indicate that significant streamlining has been undertaken which has had direct adverse effects on some of the benefits that impact assessment should deliver, particularly in Canada and the UK. The research has not examined whether streamlining has had implications for the effectiveness of impact assessment, but the causal link between streamlining and benefits does sound warning bells that merit further investigation. -- Highlights: • Investigation of the extent to which government has streamlined IA. • Evaluation framework was developed based on benefits of impact assessment. • Canada, South Africa, the United Kingdom, and Western Australia were examined. • Trajectory in last five years is attrition of benefits of impact assessment

  13. Identifying three-dimensional nested groundwater flow systems in a Tóthian basin

    Science.gov (United States)

    Wang, Xu-Sheng; Wan, Li; Jiang, Xiao-Wei; Li, Hailong; Zhou, Yangxiao; Wang, Junzhi; Ji, Xiaohui

    2017-10-01

    Nested groundwater flow systems have been revealed in Tóth's theory as the structural property of basin-scale groundwater circulation but were only well known with two-dimensional (2D) profile models. The method of searching special streamlines across stagnation points for partitioning flow systems, which has been successfully applied in the 2D models, has never been implemented for three-dimensional (3D) Tóthian basins because of the difficulty in solving the dual stream functions. Alternatively, a new method is developed to investigate 3D nested groundwater flow systems without determination of stagnation points. Connective indices are defined to quantify the connection between individual recharge and discharge zones along streamlines. Groundwater circulation cells (GWCCs) are identified according to the distribution of the connective indices and then grouped into local, intermediate and regional flow systems. This method requires existing solution of the flow velocity vector and is implemented via particle tracking technique. It is applied in a hypothetical 3D Tóthian basin with an analytical solution of the flow field and in a real-world basin with a numerical modeling approach. Different spatial patterns of flow systems compared to 2D profile models are found. The outcrops boundaries of GWCCs on water table may significantly deviate from and are not parallel to the nearby water table divides. Topological network is proposed to represent the linked recharge-discharge zones through closed and open GWCCs. Sensitivity analysis indicates that the development of GWCCs depends on the basin geometry, hydraulic parameters and water table shape.

  14. Recirculation, stagnation and ventilation: The 2014 legionella episode

    Science.gov (United States)

    Russo, Ana; Soares, Pedro M. M.; Gouveia, Célia M.; Cardoso, Rita M.; Trigo, Ricardo M.

    2017-04-01

    Legionella transmission through the atmosphere is unusual, but not unprecedented. A scientific paper published in 2006 reports a surge in Pas-de-Calais, France, in which 86 people have been infected by bacteria released by a cooling tower more than 6 km away [3]. Similarly, in Norway, in 2005, there was another case where contamination spread beyond 10 km, although more concentrated within a radius of 1 km from an industrial unit [2]. An unprecedented large Legionella outbreak occurred in November 2014 nearby Lisbon, Portugal. As of 7 November 2014, 375 individuals become hill and 12 died infected by the Legionella pneumophila bacteria, contracted by inhalation of steam droplets of contaminated water (aerosols). These droplets are so small that can carry the bacteria directly to the lungs, depositing it in the alveoli. One way of studying the propagation of legionella episodes is through the use of aerosol dispersion models. However, such approaches often require detailed 3D high resolution wind data over the region, which isn't often available for long periods. The likely impact of wind on legionella transmission can also be understood based on the analysis of special types of flow conditions such as stagnation, recirculation and ventilation [1, 4]. The Allwine and Whiteman (AW) approach constitutes a straightforward method to assess the assimilative and dispersal capacities of different airsheds [1,4], as it only requires hourly wind components. Thus, it has the advantage of not needing surface and upper air meteorological observations and a previous knowledge of the atmospheric transport and dispersion conditions. The objective of this study is to analyze if the legionella outbreak event which took place in November 2014 had extreme potential recirculation and/or stagnation characteristics. In order to accomplish the proposed objective, the AW approach was applied for a hindcast time-series covering the affected area (1989-2007) and then for an independent

  15. Streamline-concentration balance model for in-situ uranium leaching and site restoration

    International Nuclear Information System (INIS)

    Bommer, P.M.; Schechter, R.S.; Humenick, M.J.

    1981-03-01

    This work presents two computer models. One describes in-situ uranium leaching and the other describes post leaching site restoration. Both models use a streamline generator to set up the flow field over the reservoir. The leaching model then uses the flow data in a concentration balance along each streamline coupled with the appropriate reaction kinetics to calculate uranium production. The restoration model uses the same procedure except that binary cation exchange is used as the restoring mechanism along each streamline and leaching cation clean up is simulated. The mathematical basis for each model is shown in detail along with the computational schemes used. Finally, the two models have been used with several data sets to point out their capabilities and to illustrate important leaching and restoration parameters and schemes

  16. Streamline-concentration balance model for in situ uranium leaching and site restoration

    International Nuclear Information System (INIS)

    Bommer, P.M.

    1979-01-01

    This work presents two computer models. One describes in situ uranium leaching and the other describes post leaching site restoration. Both models use a streamline generator to set up the flow field over the reservoir. The leaching model then uses the flow data in a concentration balance along each streamline coupled with the appropriate reaction kinetics to calculate uranium production. The restoration model uses the same procedure ecept that binary cation exchange is used as the restoring mechanism along each streamline and leaching cation clean up is stimulated. The mathematical basis for each model is shown in detail along with the computational schemes used. Finally, the two models have been used with several data sets to point out their capabilities and to illustrate important leaching and restoration parameters and schemes

  17. Stagnation point flow and heat transfer for a viscoelastic fluid ...

    Indian Academy of Sciences (India)

    M REZA

    2017-11-09

    Nov 9, 2017 ... MS received 15 August 2016; revised 26 February 2017; accepted 15 March 2017; published online 9 ... surface has several engineering applications within, for ... viscoelastic fluids in several industrial manufacturing pro-.

  18. Effect of outer stagnation pressure on jet structure in supersonic coaxial jet

    International Nuclear Information System (INIS)

    Kim, Myoung Jong; Woo, Sang Woo; Lee, Byeong Eun; Kwon, Soon Bum

    2001-01-01

    The characteristics of dual coaxial jet which composed of inner supersonic nozzle of 26500 in constant expansion rate with 1.91 design Mach number and outer converging one with 40 .deg. C converging angle with the variation of outer nozzle stagnation pressure are experimentally investigated in this paper. In which the stagnation pressure for the inner supersonic nozzle is 750kPa thus, the inner jet leaving the nozzle is slightly underexpanded. The plenum pressure of outer nozzle are varied from 200 to 600kPa. Flow visualizations by shadowgraph method, impact pressure and centerline static pressure measurements of dual coaxial jet are presented. The results show that the presence of outer jet affects significantly the structures and pressure distributions of inner jet. And outer jet causes Mach disk which does not appear for the case of single jet stream. As the stagnation pressure of outer jet increases, impact pressure undulation is severe, but the average impact pressure keeps high far downstream

  19. Streamlining the Bankability Process using International Standards

    Energy Technology Data Exchange (ETDEWEB)

    Kurtz, Sarah [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Repins, Ingrid L [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Kelly, George [Sunset Technology, Mount Airy, MD; Ramu, Govind [SunPower, San Jose, California; Heinz, Matthias [TUV Rheinland, Cologne, Germany; Chen, Yingnan [CGC (China General Certification Center), Beijing; Wohlgemuth, John [PowerMark, Union Hall, VA; Lokanath, Sumanth [First Solar, Tempe, Arizona; Daniels, Eric [Suncycle USA, Frederick MD; Hsi, Edward [Swiss RE, Zurich, Switzerland; Yamamichi, Masaaki [RTS, Trumbull, CT

    2017-09-27

    NREL has supported the international efforts to create a streamlined process for documenting bankability and/or completion of each step of a PV project plan. IECRE was created for this purpose in 2014. This poster describes the goals, current status of this effort, and how individuals and companies can become involved.

  20. Hydrodynamic Drag on Streamlined Projectiles and Cavities

    KAUST Repository

    Jetly, Aditya

    2016-04-19

    The air cavity formation resulting from the water-entry of solid objects has been the subject of extensive research due to its application in various fields such as biology, marine vehicles, sports and oil and gas industries. Recently we demonstrated that at certain conditions following the closing of the air cavity formed by the initial impact of a superhydrophobic sphere on a free water surface a stable streamlined shape air cavity can remain attached to the sphere. The formation of superhydrophobic sphere and attached air cavity reaches a steady state during the free fall. In this thesis we further explore this novel phenomenon to quantify the drag on streamlined shape cavities. The drag on the sphere-cavity formation is then compared with the drag on solid projectile which were designed to have self-similar shape to that of the cavity. The solid projectiles of adjustable weight were produced using 3D printing technique. In a set of experiments on the free fall of projectile we determined the variation of projectiles drag coefficient as a function of the projectiles length to diameter ratio and the projectiles specific weight, covering a range of intermediate Reynolds number, Re ~ 104 – 105 which are characteristic for our streamlined cavity experiments. Parallel free fall experiment with sphere attached streamlined air cavity and projectile of the same shape and effective weight clearly demonstrated the drag reduction effect due to the stress-free boundary condition at cavity liquid interface. The streamlined cavity experiments can be used as the upper bound estimate of the drag reduction by air layers naturally sustained on superhydrophobic surfaces in contact with water. In the final part of the thesis we design an experiment to test the drag reduction capacity of robust superhydrophobic coatings deposited on the surface of various model vessels.

  1. Stagnation morphology in Magnetized Liner Inertial Fusion experiments

    Science.gov (United States)

    Gomez, M. R.; Harding, E. C.; Ampleford, D. J.; Jennings, C. A.; Awe, T. J.; Chandler, G. A.; Glinsky, M. E.; Hahn, K. D.; Hansen, S. B.; Jones, B.; Knapp, P. F.; Martin, M. R.; Peterson, K. J.; Rochau, G. A.; Ruiz, C. L.; Schmit, P. F.; Sinars, D. B.; Slutz, S. A.; Weis, M. R.; Yu, E. P.

    2017-10-01

    In Magnetized Liner Inertial Fusion (MagLIF) experiments on the Z facility, an axial current of 15-20 MA is driven through a thick metal cylinder containing axially-magnetized, laser-heated deuterium fuel. The cylinder implodes, further heating the fuel and amplifying the axial B-field. Instabilities, such as magneto-Rayleigh-Taylor, develop on the exterior of the liner and may feed through to the inner surface during the implosion. Monochromatic x-ray emission at stagnation shows the stagnation column is quasi-helical with axial variations in intensity. Recent experiments demonstrated that the stagnation emission structure changed with modifications to the target wall thickness. Additionally, applying a thick dielectric coating to the exterior of the target modified the stagnation column. A new version of the x-ray self-emission diagnostic has been developed to investigate stagnation with higher resolution. Sandia National Laboratories is a multi-mission laboratory managed and operated by National Technology & Engineering Solutions of Sandia, LLC., a wholly owned subsidiary of Honeywell International, Inc., for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-NA0003525.

  2. Response of air stagnation frequency to anthropogenically enhanced radiative forcing

    International Nuclear Information System (INIS)

    Horton, Daniel E; Diffenbaugh, Noah S; Harshvardhan

    2012-01-01

    Stagnant atmospheric conditions can lead to hazardous air quality by allowing ozone and particulate matter to accumulate and persist in the near-surface environment. By changing atmospheric circulation and precipitation patterns, global warming could alter the meteorological factors that regulate air stagnation frequency. We analyze the response of the National Climatic Data Center (NCDC) air stagnation index (ASI) to anthropogenically enhanced radiative forcing using global climate model projections of late-21st century climate change (SRESA1B scenario). Our results indicate that the atmospheric conditions over the highly populated, highly industrialized regions of the eastern United States, Mediterranean Europe, and eastern China are particularly sensitive to global warming, with the occurrence of stagnant conditions projected to increase by 12–25% relative to late-20th century stagnation frequencies (3–18 + days yr −1 ). Changes in the position/strength of the polar jet, in the occurrence of light surface winds, and in the number of precipitation-free days all contribute to more frequent late-21st century air mass stagnation over these high-population regions. In addition, we find substantial inter-model spread in the simulated response of stagnation conditions over some regions using either native or bias corrected global climate model simulations, suggesting that changes in the atmospheric circulation and/or the distribution of precipitation represent important sources of uncertainty in the response of air quality to global warming. (letter)

  3. Streamlining air import operations by trade facilitation measures

    Directory of Open Access Journals (Sweden)

    Yuri da Cunha Ferreira

    2017-12-01

    Full Text Available Global operations are subject to considerable uncertainties. Due to the Trade Facilitation Agreement that became effective in February 2017, the study of measures to streamline customs controls is urgent. This study aims to assess the impact of trade facilitation measures on import flows. An experimental study was performed in the largest cargo airport in South America through discrete-event simulation and design of experiments. Operation impacts of three trade facilitation measures are assessed on import flow by air. We shed light in the following trade facilitation measures: the use of X-ray equipment for physical inspection; increase of the number of qualified companies in the trade facilitation program; performance targets for customs officials. All trade facilitation measures used indicated potential to provide more predictability, cost savings, time reduction, and increase in security in international supply chain.

  4. Streamline Patterns and their Bifurcations near a wall with Navier slip Boundary Conditions

    DEFF Research Database (Denmark)

    Tophøj, Laust; Møller, Søren; Brøns, Morten

    2006-01-01

    We consider the two-dimensional topology of streamlines near a surface where the Navier slip boundary condition applies. Using transformations to bring the streamfunction in a simple normal form, we obtain bifurcation diagrams of streamline patterns under variation of one or two external parameters....... Topologically, these are identical with the ones previously found for no-slip surfaces. We use the theory to analyze the Stokes flow inside a circle, and show how it can be used to predict new bifurcation phenomena. ©2006 American Institute of Physics...

  5. Analysis of Streamline Separation at Infinity Using Time-Discrete Markov Chains.

    Science.gov (United States)

    Reich, W; Scheuermann, G

    2012-12-01

    Existing methods for analyzing separation of streamlines are often restricted to a finite time or a local area. In our paper we introduce a new method that complements them by allowing an infinite-time-evaluation of steady planar vector fields. Our algorithm unifies combinatorial and probabilistic methods and introduces the concept of separation in time-discrete Markov-Chains. We compute particle distributions instead of the streamlines of single particles. We encode the flow into a map and then into a transition matrix for each time direction. Finally, we compare the results of our grid-independent algorithm to the popular Finite-Time-Lyapunov-Exponents and discuss the discrepancies.

  6. Behavior of a solar collector loop during stagnation

    DEFF Research Database (Denmark)

    Chen, Ziqian; Dragsted, Janne; Furbo, Simon

    2015-01-01

    A mathematical model simulating the emptying behavior of a pressurized solar collector loop with solar collectors with a good emptying behavior is developed and validated with measured data. The calculated results are in good agreement with the measured results. The developed simulation model...... is therefore suitable to determine the behavior of a solar collector loop during stagnation. A volume ratio R, which is the ratio of the volume of the vapour in the upper pipes of the solar collector loop during stagnation and the fluid content of solar collectors, is introduced to determine the mass...... of the collector fluid pushed into the expansion vessel during stagnation, Min. A correlation function for the mass Min and the volume ratio R for solar collector loops is obtained. The function can be used to determine a suitable size of expansion vessels for solar collector loops....

  7. Aerosol impacts on regional trends in atmospheric stagnation

    Science.gov (United States)

    Mascioli, N. R.; Fiore, A. M.; Previdi, M. J.

    2017-12-01

    Extreme pollution events pose a significant threat to human health and are a leading cause of premature mortality worldwide. While emissions of atmospheric pollutants and their precursors are projected to decrease in the future due to air quality legislation, future climate change may affect the underlying meteorological conditions that contribute to extreme pollution events. Stagnation events, characterized by weak winds and an absence of precipitation, contribute to extreme pollution by halting the removal of pollutants via advection and wet deposition. Here, we use a global climate model (GFDL-CM3) to show that regional stagnation trends over the historical period (1860-2005) are driven by changes in anthropogenic aerosol emissions, rather than rising greenhouse gases. In the northeastern and central United States, aerosol-induced changes in surface and upper level winds have produced significant decreases in the number of stagnant summer days, while decreasing precipitation in the southeast US has increased the number of stagnant summer days. Significant drying over eastern China in response to aerosol forcing contributed to increased stagnation. Additionally, this region was found to be particularly sensitive to changes in local emissions, indicating that improving air quality will also lessen stagnation. In Europe, we find a dipole pattern wherein stagnation decreases over southern Europe and increases over northern Europe in response to global increases in aerosol emissions. We hypothesize that this is due to changes in the large-scale circulation patterns associated with a poleward shift of the North Atlantic storm track. We find that in the future, the combination of declining aerosol emissions and the continued rise of greenhouse gas emissions will lead to a reversal of the historical stagnation trends.

  8. Self streamlining wind tunnel: Further low speed testing and final design studies for the transonic facility

    Science.gov (United States)

    Wolf, S. W. D.

    1978-01-01

    Work was continued with the low speed self streamlining wind tunnel (SSWT) using the NACA 0012-64 airfoil in an effort to explain the discrepancies between the NASA Langley low turbulence pressure tunnel (LTPT) and SSWT results obtained with the airfoil stalled. Conventional wind tunnel corrections were applied to straight wall SSWT airfoil data, to illustrate the inadequacy of standard correction techniques in circumstances of high blockage. Also one SSWT test was re-run at different air speeds to investigate the effects of such changes (perhaps through changes in Reynold's number and freestream turbulence levels) on airfoil data and wall contours. Mechanical design analyses for the transonic self-streamlining wind tunnel (TSWT) were completed by the application of theoretical airfoil flow field data to the elastic beam and streamline analysis. The control system for the transonic facility, which will eventually allow on-line computer operation of the wind tunnel, was outlined.

  9. OFF-Stagnation point testing in plasma facility

    Science.gov (United States)

    Viladegut, A.; Chazot, O.

    2015-06-01

    Reentry space vehicles face extreme conditions of heat flux when interacting with the atmosphere at hypersonic velocities. Stagnation point heat flux is normally used as a reference for Thermal Protection Material (TPS) design; however, many critical phenomena also occur at off-stagnation point. This paper adresses the implementation of an offstagnation point methodology able to duplicate in ground facility the hypersonic boundary layer over a flat plate model. The first analysis using two-dimensional (2D) computational fluid dynamics (CFD) simulations is carried out to understand the limitations of this methodology when applying it in plasma wind tunnel. The results from the testing campaign at VKI Plasmatron are also presented.

  10. Streamlining Research by Using Existing Tools

    OpenAIRE

    Greene, Sarah M.; Baldwin, Laura-Mae; Dolor, Rowena J.; Thompson, Ella; Neale, Anne Victoria

    2011-01-01

    Over the past two decades, the health research enterprise has matured rapidly, and many recognize an urgent need to translate pertinent research results into practice, to help improve the quality, accessibility, and affordability of U.S. health care. Streamlining research operations would speed translation, particularly for multi-site collaborations. However, the culture of research discourages reusing or adapting existing resources or study materials. Too often, researchers start studies and...

  11. Effects of Gyejibongnyeong-hwan on dysmenorrhea caused by blood stagnation: study protocol for a randomized controlled trial

    Directory of Open Access Journals (Sweden)

    Park Jeong-Su

    2012-01-01

    Full Text Available Abstract Background Gyejibongnyeong-hwan (GJBNH is one of the most popular Korean medicine formulas for menstrual pain of dysmenorrhea. The concept of blood stagnation in Korean medicine is considered the main factor of causing abdominal pain, or cramps, during menstrual periods. To treat the symptoms, GJBNH is used to fluidify the stagnated blood and induce the blood flow to be smooth, reducing pain as the result. The purpose of this trial is to identify the efficacy of GJBNH in dysmenorrhea caused by blood stagnation. Methods This study is a multi-centre, randomised, double-blind, controlled trial with two parallel arms: the group taking GJBNH and the group taking placebo. 100 patients (women from age 18 to 35 will be enrolled to the trial. Through randomization 50 patients will be in experiment arm, and the other 50 patients will be in control arm. At the second visit (baseline, all participants who were already screened that they fulfil both the inclusion and the exclusion criteria will be randomised into two groups. Each group will take the intervention three times per day during two menstrual cycles. After the treatment for two cycles, each patient will be followed up during their 3rd, 4th and 5th menstrual cycles. From the screening (Visit 1 through the second follow-up (Visit 6 the entire process will take 25 weeks. Discussion This trial will provide evidence for the effectiveness of GJBNH in treating periodical pain due to dysmenorrhea that is caused by blood stagnation. The primary outcome between the two groups will be measured by changes in the Visual Analogue Score (VAS of pain. The secondary outcome will be measured by the Blood Stagnation Scale, the Short-form McGill questionnaire and the COX menstrual symptom scale. Analysis of covariance (ANCOVA and repeated measured ANOVA will be used to analyze the data analysis. Trial registration Current Controlled Trials: ISRCTN30426947

  12. Southern Ocean overturning across streamlines in an eddying simulation of the Antarctic Circumpolar Current

    Directory of Open Access Journals (Sweden)

    A. M. Treguier

    2007-12-01

    Full Text Available An eddying global model is used to study the characteristics of the Antarctic Circumpolar Current (ACC in a streamline-following framework. Previous model-based estimates of the meridional circulation were calculated using zonal averages: this method leads to a counter-intuitive poleward circulation of the less dense waters, and underestimates the eddy effects. We show that on the contrary, the upper ocean circulation across streamlines agrees with the theoretical view: an equatorward mean flow partially cancelled by a poleward eddy mass flux. Two model simulations, in which the buoyancy forcing above the ACC changes from positive to negative, suggest that the relationship between the residual meridional circulation and the surface buoyancy flux is not as straightforward as assumed by the simplest theoretical models: the sign of the residual circulation cannot be inferred from the surface buoyancy forcing only. Among the other processes that likely play a part in setting the meridional circulation, our model results emphasize the complex three-dimensional structure of the ACC (probably not well accounted for in streamline-averaged, two-dimensional models and the distinct role of temperature and salinity in the definition of the density field. Heat and salt transports by the time-mean flow are important even across time-mean streamlines. Heat and salt are balanced in the ACC, the model drift being small, but the nonlinearity of the equation of state cannot be ignored in the density balance.

  13. Effects of platinum stagnation surface on the lean extinction limits of premixed methane/air flames at moderate surface temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Wiswall, J.T.; Li, J.; Wooldridge, M.S.; Im, H.G. [Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI (United States)

    2011-01-15

    A stagnation flow reactor was used to study the effects of platinum on the lean flammability limits of atmospheric pressure premixed methane/air flames at moderate stagnation surface temperatures. Experimental and computational methods were used to quantify the equivalence ratio at the lean extinction limit ({phi}{sub ext}) and the corresponding stagnation surface temperature (T{sub s}). A range of flow rates (57-90 cm/s) and corresponding strain rates were considered. The results indicate that the gas-phase methane/air flames are sufficiently strong relative to the heterogeneous chemistry for T{sub s} conditions less than 750 K that the platinum does not affect {phi}{sub ext}. The computational results are in good agreement with the experimentally observed trends and further indicate that higher reactant flow rates (>139 cm/s) and levels of dilution (>{proportional_to}10% N{sub 2}) are required to weaken the gas-phase flame sufficiently for surface reaction to play a positive role on extending the lean flammability limits. (author)

  14. Streamlined approach to waste management at CRL

    International Nuclear Information System (INIS)

    Adams, L.; Campbell, B.

    2011-01-01

    Radioactive, mixed, hazardous and non-hazardous wastes have been and continue to be generated at Chalk River Laboratories (CRL) as a result of research and development activities and operations since the 1940s. Over the years, the wastes produced as a byproduct of activities delivering the core missions of the CRL site have been of many types, and today, over thirty distinct waste streams have been identified, all requiring efficient management. With the commencement of decommissioning of the legacy created as part of the development of the Canadian nuclear industry, the volumes and range of wastes to be managed have been increasing in the near term, and this trend will continue into the future. The development of a streamlined approach to waste management is a key to successful waste management at CRL. Waste management guidelines that address all of the requirements have become complex, and so have the various waste management groups receiving waste, with their many different processes and capabilities. This has led to difficulties for waste generators in understanding all of the requirements to be satisfied for the various CRL waste receivers, whose primary concerns are to be safe and in compliance with their acceptance criteria and license conditions. As a result, waste movement on site can often be very slow, especially for non-routine waste types. Recognizing an opportunity for improvement, the Waste Management organization at CRL has implemented a more streamlined approach with emphasis on early identification of waste type and possible disposition path. This paper presents a streamlined approach to waste identification and waste management at CRL, the implementation methodology applied and the early results achieved from this process improvement. (author)

  15. Lightroom 5 streamlining your digital photography process

    CERN Document Server

    Sylvan, Rob

    2014-01-01

    Manage your images with Lightroom and this beautifully illustrated guide Image management can soak up huge amounts of a photographer's time, but help is on hand. This complete guides teaches you how to use Adobe Lightroom 5 to import, manage, edit, and showcase large quantities of images with impressive results. The authors, both professional photographers and Lightroom experts, walk you through step by step, demonstrating real-world techniques as well as a variety of practical tips, tricks, and shortcuts that save you time. Streamline image management tasks like a pro, and get back to doing

  16. Streamlining environmental product declarations: a stage model

    Science.gov (United States)

    Lefebvre, Elisabeth; Lefebvre, Louis A.; Talbot, Stephane; Le Hen, Gael

    2001-02-01

    General public environmental awareness and education is increasing, therefore stimulating the demand for reliable, objective and comparable information about products' environmental performances. The recently published standard series ISO 14040 and ISO 14025 are normalizing the preparation of Environmental Product Declarations (EPDs) containing comprehensive information relevant to a product's environmental impact during its life cycle. So far, only a few environmentally leading manufacturing organizations have experimented the preparation of EPDs (mostly from Europe), demonstrating its great potential as a marketing weapon. However the preparation of EPDs is a complex process, requiring collection and analysis of massive amounts of information coming from disparate sources (suppliers, sub-contractors, etc.). In a foreseeable future, the streamlining of the EPD preparation process will require product manufacturers to adapt their information systems (ERP, MES, SCADA) in order to make them capable of gathering, and transmitting the appropriate environmental information. It also requires strong functional integration all along the product supply chain in order to ensure that all the information is made available in a standardized and timely manner. The goal of the present paper is two fold: first to propose a transitional model towards green supply chain management and EPD preparation; second to identify key technologies and methodologies allowing to streamline the EPD process and subsequently the transition toward sustainable product development

  17. Quantification of topological changes of vorticity contours in two-dimensional Navier-Stokes flow.

    Science.gov (United States)

    Ohkitani, Koji; Al Sulti, Fayeza

    2010-06-01

    A characterization of reconnection of vorticity contours is made by direct numerical simulations of the two-dimensional Navier-Stokes flow at a relatively low Reynolds number. We identify all the critical points of the vorticity field and classify them by solving an eigenvalue problem of its Hessian matrix on the basis of critical-point theory. The numbers of hyperbolic (saddles) and elliptic (minima and maxima) points are confirmed to satisfy Euler's index theorem numerically. Time evolution of these indices is studied for a simple initial condition. Generally speaking, we have found that the indices are found to decrease in number with time. This result is discussed in connection with related works on streamline topology, in particular, the relationship between stagnation points and the dissipation. Associated elementary procedures in physical space, the merging of vortices, are studied in detail for a number of snapshots. A similar analysis is also done using the stream function.

  18. Kinetic analysis of thermally relativistic flow with dissipation

    International Nuclear Information System (INIS)

    Yano, Ryosuke; Suzuki, Kojiro

    2011-01-01

    Nonequilibrium flow of thermally relativistic matter with dissipation is considered in the framework of the relativistic kinetic theory. As an object of the analysis, the supersonic rarefied flow of thermally relativistic matter around the triangle prism is analyzed using the Anderson-Witting model. Obtained numerical results indicate that the flow field changes in accordance with the flow velocity and temperature of the uniform flow owing to both effects derived from the Lorentz contraction and thermally relativistic effects, even when the Mach number of the uniform flow is fixed. The profiles of the heat flux along the stagnation streamline can be approximated on the basis of the relativistic Navier-Stokes-Fourier (NSF) law except for a strong nonequilibrium regime such as the middle of the shock wave and the vicinity of the wall, whereas the profile of the heat flux behind the triangle prism cannot be approximated on the basis of the relativistic NSF law owing to rarefied effects via the expansion behind the triangle prism. Additionally, the heat flux via the gradient of the static pressure is non-negligible owing to thermally relativistic effects. The profile of the dynamic pressure is different from that approximated on the basis of the NSF law, which is obtained by the Eckart decomposition. Finally, variations of convections of the mass and momentum owing to the effects derived from the Lorentz contraction and thermally relativistic effects are numerically confirmed.

  19. Investigation of Hypersonic Laminar Heating Augmentation in the Stagnation Region

    Science.gov (United States)

    Marineau, Eric C.; Lewis, Daniel R.; Smith, Michael S.; Lafferty, John F.; White, Molly E.; Amar, Adam J.

    2012-01-01

    Laminar stagnation region heating augmentation is investigated in the AEDC Tunnel 9 at Mach 10 by performing high frequency surface pressure and heat transfer measurements on the Orion CEV capsule at zero degree angle-of-attack for unit Reynolds numbers between 0.5 and 15 million per foot. Heating augmentation increases with Reynolds number, but is also model size dependent as it is absent on a 1.25-inch diameter model at Reynolds numbers where it reaches up to 15% on a 7-inch model. Heat transfer space-time correlations on the 7-inch model show that disturbances convect at the boundary layer edge velocity and that the streamwise integral scale increases with distance. Therefore, vorticity amplification due to stretching and piling-up in the stagnation region appears to be responsible for the stagnation point heating augmentation on the larger model. This assumption is reinforced by the f(exp -11/3) dependence of the surface pressure spectrum compared to the f(exp -1) dependence in the free stream. Vorticity amplification does not occur on the 1.25- inch model because the disturbances are too large. Improved free stream fluctuation measurements will be required to determine if significant vorticity is present upstream or mostly generated behind the bow shock.

  20. Quantum mechanical streamlines. I - Square potential barrier

    Science.gov (United States)

    Hirschfelder, J. O.; Christoph, A. C.; Palke, W. E.

    1974-01-01

    Exact numerical calculations are made for scattering of quantum mechanical particles hitting a square two-dimensional potential barrier (an exact analog of the Goos-Haenchen optical experiments). Quantum mechanical streamlines are plotted and found to be smooth and continuous, to have continuous first derivatives even through the classical forbidden region, and to form quantized vortices around each of the nodal points. A comparison is made between the present numerical calculations and the stationary wave approximation, and good agreement is found between both the Goos-Haenchen shifts and the reflection coefficients. The time-independent Schroedinger equation for real wavefunctions is reduced to solving a nonlinear first-order partial differential equation, leading to a generalization of the Prager-Hirschfelder perturbation scheme. Implications of the hydrodynamical formulation of quantum mechanics are discussed, and cases are cited where quantum and classical mechanical motions are identical.

  1. A streamlined failure mode and effects analysis

    Energy Technology Data Exchange (ETDEWEB)

    Ford, Eric C., E-mail: eford@uw.edu; Smith, Koren; Terezakis, Stephanie; Croog, Victoria; Gollamudi, Smitha; Gage, Irene; Keck, Jordie; DeWeese, Theodore; Sibley, Greg [Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University, Baltimore, MD 21287 (United States)

    2014-06-15

    Purpose: Explore the feasibility and impact of a streamlined failure mode and effects analysis (FMEA) using a structured process that is designed to minimize staff effort. Methods: FMEA for the external beam process was conducted at an affiliate radiation oncology center that treats approximately 60 patients per day. A structured FMEA process was developed which included clearly defined roles and goals for each phase. A core group of seven people was identified and a facilitator was chosen to lead the effort. Failure modes were identified and scored according to the FMEA formalism. A risk priority number,RPN, was calculated and used to rank failure modes. Failure modes with RPN > 150 received safety improvement interventions. Staff effort was carefully tracked throughout the project. Results: Fifty-two failure modes were identified, 22 collected during meetings, and 30 from take-home worksheets. The four top-ranked failure modes were: delay in film check, missing pacemaker protocol/consent, critical structures not contoured, and pregnant patient simulated without the team's knowledge of the pregnancy. These four failure modes hadRPN > 150 and received safety interventions. The FMEA was completed in one month in four 1-h meetings. A total of 55 staff hours were required and, additionally, 20 h by the facilitator. Conclusions: Streamlined FMEA provides a means of accomplishing a relatively large-scale analysis with modest effort. One potential value of FMEA is that it potentially provides a means of measuring the impact of quality improvement efforts through a reduction in risk scores. Future study of this possibility is needed.

  2. Streamlining the license renewal review process

    International Nuclear Information System (INIS)

    Dozier, J.; Lee, S.; Kuo, P.T.

    2001-01-01

    The staff of the NRC has been developing three regulatory guidance documents for license renewal: the Generic Aging Lessons Learned (GALL) report, Standard Review Plan for License Renewal (SRP-LR), and Regulatory Guide (RG) for Standard Format and Content for Applications to Renew Nuclear Power Plant Operating Licenses. These documents are designed to streamline the license renewal review process by providing clear guidance for license renewal applicants and the NRC staff in preparing and reviewing license renewal applications. The GALL report systematically catalogs aging effects on structures and components; identifies the relevant existing plant programs; and evaluates the existing programs against the attributes considered necessary for an aging management program to be acceptable for license renewal. The GALL report also provides guidance for the augmentation of existing plant programs for license renewal. The revised SRP-LR allows an applicant to reference the GALL report to preclude further NRC staff evaluation if the plant's existing programs meet the criteria described in the GALL report. During the review process, the NRC staff will focus primarily on existing programs that should be augmented or new programs developed specifically for license renewal. The Regulatory Guide is expected to endorse the Nuclear Energy Institute (NEI) guideline, NEI 95-10, Revision 2, entitled 'Industry Guideline for Implementing the Requirements of 10 CFR Part 54 - The License Renewal Rule', which provides guidance for preparing a license renewal application. This paper will provide an introduction to the GALL report, SRP-LR, Regulatory Guide, and NEI 95-10 to show how these documents are interrelated and how they will be used to streamline the license renewal review process. This topic will be of interest to domestic power utilities considering license renewal and international ICONE participants seeking state-of-the-art information about license renewal in the United States

  3. A streamlined failure mode and effects analysis

    International Nuclear Information System (INIS)

    Ford, Eric C.; Smith, Koren; Terezakis, Stephanie; Croog, Victoria; Gollamudi, Smitha; Gage, Irene; Keck, Jordie; DeWeese, Theodore; Sibley, Greg

    2014-01-01

    Purpose: Explore the feasibility and impact of a streamlined failure mode and effects analysis (FMEA) using a structured process that is designed to minimize staff effort. Methods: FMEA for the external beam process was conducted at an affiliate radiation oncology center that treats approximately 60 patients per day. A structured FMEA process was developed which included clearly defined roles and goals for each phase. A core group of seven people was identified and a facilitator was chosen to lead the effort. Failure modes were identified and scored according to the FMEA formalism. A risk priority number,RPN, was calculated and used to rank failure modes. Failure modes with RPN > 150 received safety improvement interventions. Staff effort was carefully tracked throughout the project. Results: Fifty-two failure modes were identified, 22 collected during meetings, and 30 from take-home worksheets. The four top-ranked failure modes were: delay in film check, missing pacemaker protocol/consent, critical structures not contoured, and pregnant patient simulated without the team's knowledge of the pregnancy. These four failure modes hadRPN > 150 and received safety interventions. The FMEA was completed in one month in four 1-h meetings. A total of 55 staff hours were required and, additionally, 20 h by the facilitator. Conclusions: Streamlined FMEA provides a means of accomplishing a relatively large-scale analysis with modest effort. One potential value of FMEA is that it potentially provides a means of measuring the impact of quality improvement efforts through a reduction in risk scores. Future study of this possibility is needed

  4. A streamlined failure mode and effects analysis.

    Science.gov (United States)

    Ford, Eric C; Smith, Koren; Terezakis, Stephanie; Croog, Victoria; Gollamudi, Smitha; Gage, Irene; Keck, Jordie; DeWeese, Theodore; Sibley, Greg

    2014-06-01

    Explore the feasibility and impact of a streamlined failure mode and effects analysis (FMEA) using a structured process that is designed to minimize staff effort. FMEA for the external beam process was conducted at an affiliate radiation oncology center that treats approximately 60 patients per day. A structured FMEA process was developed which included clearly defined roles and goals for each phase. A core group of seven people was identified and a facilitator was chosen to lead the effort. Failure modes were identified and scored according to the FMEA formalism. A risk priority number,RPN, was calculated and used to rank failure modes. Failure modes with RPN > 150 received safety improvement interventions. Staff effort was carefully tracked throughout the project. Fifty-two failure modes were identified, 22 collected during meetings, and 30 from take-home worksheets. The four top-ranked failure modes were: delay in film check, missing pacemaker protocol/consent, critical structures not contoured, and pregnant patient simulated without the team's knowledge of the pregnancy. These four failure modes had RPN > 150 and received safety interventions. The FMEA was completed in one month in four 1-h meetings. A total of 55 staff hours were required and, additionally, 20 h by the facilitator. Streamlined FMEA provides a means of accomplishing a relatively large-scale analysis with modest effort. One potential value of FMEA is that it potentially provides a means of measuring the impact of quality improvement efforts through a reduction in risk scores. Future study of this possibility is needed.

  5. Calculation of heat transfer in transversely stream-lined tube bundles with chess arrangement

    International Nuclear Information System (INIS)

    Migaj, V.K.

    1978-01-01

    A semiempirical theory of heat transfer in transversely stream-lined chess-board tube bundles has been developed. The theory is based on a single cylinder model and involves external flow parameter evaluation on the basis of the solidification principle of a vortex zone. The effect of turbulence is estimated according to experimental results. The method is extended to both average and local heat transfer coefficients. Comparison with experiment shows satisfactory agreement

  6. The Effects of Propulsive Jetting on Drag of a Streamlined body

    Science.gov (United States)

    Krieg, Michael; Mohseni, Kamran

    2017-11-01

    Recently an abundance of bioinspired underwater vehicles have emerged to leverage eons of evolution. Our group has developed a propulsion technique inspired by jellyfish and squid. Propulsive jets are generated by ingesting and expelling water from a flexible internal cavity. We have demonstrated thruster capabilities for maneuvering on AUV platforms, where the internal thruster geometry minimized forward drag; however, such a setup cannot characterize propulsive efficiency. Therefore, we created a new streamlined vehicle platform that produces unsteady jets for forward propulsion rather than maneuvering. The streamlined jetting body is placed in a water tunnel and held stationary while jetting frequency and background flow velocity are varied. For each frequency/velocity pair the flow field is measured around the surface and in the wake using PIV. Using the zero jetting frequency as a baseline for each background velocity, the passive body drag is related to the velocity distribution. For cases with active jetting the drag and jetting forces are estimated from the velocity field and compared to the passive case. For this streamlined body, the entrainment of surrounding flow into the propulsive jet can reduce drag forces in addition to the momentum transfer of the jet itself. Office of Naval Research.

  7. The impact of groundwater velocity fields on streamlines in an aquifer system with a discontinuous aquitard (Inner Mongolia, China)

    Science.gov (United States)

    Wu, Qiang; Zhao, Yingwang; Xu, Hua

    2018-04-01

    Many numerical methods that simulate groundwater flow, particularly the continuous Galerkin finite element method, do not produce velocity information directly. Many algorithms have been proposed to improve the accuracy of velocity fields computed from hydraulic potentials. The differences in the streamlines generated from velocity fields obtained using different algorithms are presented in this report. The superconvergence method employed by FEFLOW, a popular commercial code, and some dual-mesh methods proposed in recent years are selected for comparison. The applications to depict hydrogeologic conditions using streamlines are used, and errors in streamlines are shown to lead to notable errors in boundary conditions, the locations of material interfaces, fluxes and conductivities. Furthermore, the effects of the procedures used in these two types of methods, including velocity integration and local conservation, are analyzed. The method of interpolating velocities across edges using fluxes is shown to be able to eliminate errors associated with refraction points that are not located along material interfaces and streamline ends at no-flow boundaries. Local conservation is shown to be a crucial property of velocity fields and can result in more accurate streamline densities. A case study involving both three-dimensional and two-dimensional cross-sectional models of a coal mine in Inner Mongolia, China, are used to support the conclusions presented.

  8. Streamlined islands and the English Channel megaflood hypothesis

    Science.gov (United States)

    Collier, J. S.; Oggioni, F.; Gupta, S.; García-Moreno, D.; Trentesaux, A.; De Batist, M.

    2015-12-01

    Recognising ice-age catastrophic megafloods is important because they had significant impact on large-scale drainage evolution and patterns of water and sediment movement to the oceans, and likely induced very rapid, short-term effects on climate. It has been previously proposed that a drainage system on the floor of the English Channel was initiated by catastrophic flooding in the Pleistocene but this suggestion has remained controversial. Here we examine this hypothesis through an analysis of key landform features. We use a new compilation of multi- and single-beam bathymetry together with sub-bottom profiler data to establish the internal structure, planform geometry and hence origin of a set of 36 mid-channel islands. Whilst there is evidence of modern-day surficial sediment processes, the majority of the islands can be clearly demonstrated to be formed of bedrock, and are hence erosional remnants rather than depositional features. The islands display classic lemniscate or tear-drop outlines, with elongated tips pointing downstream, typical of streamlined islands formed during high-magnitude water flow. The length-to-width ratio for the entire island population is 3.4 ± 1.3 and the degree-of-elongation or k-value is 3.7 ± 1.4. These values are comparable to streamlined islands in other proven Pleistocene catastrophic flood terrains and are distinctly different to values found in modern-day rivers. The island geometries show a correlation with bedrock type: with those carved from Upper Cretaceous chalk having larger length-to-width ratios (3.2 ± 1.3) than those carved into more mixed Paleogene terrigenous sandstones, siltstones and mudstones (3.0 ± 1.5). We attribute these differences to the former rock unit having a lower skin friction which allowed longer island growth to achieve minimum drag. The Paleogene islands, although less numerous than the Chalk islands, also assume more perfect lemniscate shapes. These lithologies therefore reached island

  9. Avoiding Intellectual Stagnation: The Starship as an Expander of Minds

    Science.gov (United States)

    Crawford, Ian A.

    2014-06-01

    Interstellar exploration will advance human knowledge and culture in multiple ways. Scientifically, it will advance our understanding of the interstellar medium, stellar astrophysics, planetary science and astrobiology. In addition, significant societal and cultural benefits will result from a programme of interstellar exploration and colonisation. Most important will be the cultural stimuli resulting from expanding the horizons of human experience, and increased opportunities for the spread and diversification of life and culture through the Galaxy. Ultimately, a programme of interstellar exploration may be the only way for human (and post-human) societies to avoid the intellectual stagnation predicted for the `end of history'.

  10. Stagnation and interpenetration of laser-created colliding plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Pollaine, S.M.; Albritton, J.R.; Kauffman, R.; Keane, C.J. (Lawrence Livermore National Lab., CA (USA)); Berger, R.L.; Bosch, R.; Delameter, N.D.; Failor, B.H. (KMS Fusion, Inc., Ann Arbor, MI (USA))

    1990-11-05

    A KMS laser experiment collides Aluminum (A1) and Magnesium (Mg) plasmas. The measurements include electron density, time and space resolved Ly-alpha and He-alpha lines of Al and Mg, and x-ray images. These measurements were analyzed with a hydrodynamic code, LASNEX, and a special two-fluid code OFIS. The results strongly suggest that at early times, the Al interpenetrates the counterstreaming Mg and deposits in the dense Mg region. At late times, the Al plasma stagnates against the Mg plasma.

  11. Pressure and temperature development in solar heating system during stagnation

    DEFF Research Database (Denmark)

    Dragsted, Janne; Furbo, Simon; Chen, Ziqian

    2010-01-01

    of the pipes of the solar collector loop. During the investigation the pre-pressure of the expansion vessel and system filling pressure was changed. The investigations showed that a large pressurised expansion vessel will protect the collector loop from critically high temperatures as long as the solar......This paper presents an investigation of stagnation in solar collectors and the effects it will have on the collector loop. At a laboratory test stand at the Technical University of Denmark, a pressurized solar collector loop was designed to test different numbers of collectors and different designs...

  12. Possible Origin of Stagnation and Variability of Earth's Biodiversity

    Science.gov (United States)

    Stollmeier, Frank; Geisel, Theo; Nagler, Jan

    2014-06-01

    The magnitude and variability of Earth's biodiversity have puzzled scientists ever since paleontologic fossil databases became available. We identify and study a model of interdependent species where both endogenous and exogenous impacts determine the nonstationary extinction dynamics. The framework provides an explanation for the qualitative difference of marine and continental biodiversity growth. In particular, the stagnation of marine biodiversity may result from a global transition from an imbalanced to a balanced state of the species dependency network. The predictions of our framework are in agreement with paleontologic databases.

  13. Use of Vortex Generators to Reduce Distortion for Mach 1.6 Streamline-Traced Supersonic Inlets

    Science.gov (United States)

    Baydar, Ezgihan; Lu, Frank; Slater, John W.; Trefny, Chuck

    2016-01-01

    Reduce the total pressure distortion at the engine-fan face due to low-momentum flow caused by the interaction of an external terminal shock at the turbulent boundary layer along a streamline-traced external-compression (STEX) inlet for Mach 1.6.

  14. Standard Test Method for Calculation of Stagnation Enthalpy from Heat Transfer Theory and Experimental Measurements of Stagnation-Point Heat Transfer and Pressure

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2005-01-01

    1.1 This test method covers the calculation from heat transfer theory of the stagnation enthalpy from experimental measurements of the stagnation-point heat transfer and stagnation pressure. 1.2 Advantages 1.2.1 A value of stagnation enthalpy can be obtained at the location in the stream where the model is tested. This value gives a consistent set of data, along with heat transfer and stagnation pressure, for ablation computations. 1.2.2 This computation of stagnation enthalpy does not require the measurement of any arc heater parameters. 1.3 Limitations and ConsiderationsThere are many factors that may contribute to an error using this type of approach to calculate stagnation enthalpy, including: 1.3.1 TurbulenceThe turbulence generated by adding energy to the stream may cause deviation from the laminar equilibrium heat transfer theory. 1.3.2 Equilibrium, Nonequilibrium, or Frozen State of GasThe reaction rates and expansions may be such that the gas is far from thermodynamic equilibrium. 1.3.3 Noncat...

  15. Stagnation of ablated metal vapor in laser fusion reactor with liquid wall

    International Nuclear Information System (INIS)

    Norimatsu, T.; Nagatomo, H.; Azechi, H.; Furukawa, H.; Shimada, Y.; Kurahashi, S.; Kunugi, T.; Kajimura, Y.

    2010-11-01

    In this paper, formation of clusters by ablated materials and those stagnation at the center of a laser fusion reactor with liquid wall are discussed using improved simulation code DECORE. We will report 1) numerical simulation on formation of clusters immediately before the stagnation, 2) preliminary results on the cluster formation at the first bounce of the stagnation, 3) experimental result on the diameter measurement of micro droplets formed in a simulation experiment with back-side irradiation of laser. (author)

  16. Theoretical Calculations on Sediment Transport on Titan, and the Possible Production of Streamlined Forms

    Science.gov (United States)

    Burr, D. M.; Emery, J. P.; Lorenz, R. D.

    2005-01-01

    The Cassini Imaging Science System (ISS) has been returning images of Titan, along with other Saturnian satellites. Images taken through the 938 nm methane window see down to Titan's surface. One of the purposes of the Cassini mission is to investigate possible fluid cycling on Titan. Lemniscate features shown recently and radar evidence of surface flow prompted us to consider theoretically the creation by methane fluid flow of streamlined forms on Titan. This follows work by other groups in theoretical consideration of fluid motion on Titan's surface.

  17. Stagnation, circulation, and erosion of granular materials through belt conveyor sluice gate

    Science.gov (United States)

    Pohlman, Nicholas; Moralda, Michael; Dunne, Ryan

    2013-11-01

    Control of flow rates in conversion reactors for discrete materials like biomass can be achieved in belt conveyors through a combination of belt speed, hopper size, and aperture opening. As material is extracted from the bottom of the storage hopper, other material cannot achieve plug flow and therefore is restricted from exiting through a sluice-gate type opening. The excess material moves vertically from the opening causing a pile up and recirculation back along the free surface of the hopper. Experimental results obtained through high speed imaging show the position of the stagnation point as well as the rate of circulation is dependent on the mass flow rate achieved and instantaneous fill level. The movement of material into the plug flow along the belt allows verification of deposition models on erodible beds rather than rigid surfaces with artificial roughness of glued particles. Similarly, the pile-up at the exit influences the efficiency of the transport affecting the narrow energy return on investment of biomass resources. The laboratory-scale behavior can therefore be translated into industrial performance metrics for increased operational efficiency. This work is supported by the NSF REU Site Operation E-Tank under award number 1156789.

  18. Damage Detection with Streamlined Structural Health Monitoring Data

    Directory of Open Access Journals (Sweden)

    Jian Li

    2015-04-01

    Full Text Available The huge amounts of sensor data generated by large scale sensor networks in on-line structural health monitoring (SHM systems often overwhelms the systems’ capacity for data transmission and analysis. This paper presents a new concept for an integrated SHM system in which a streamlined data flow is used as a unifying thread to integrate the individual components of on-line SHM systems. Such an integrated SHM system has a few desirable functionalities including embedded sensor data compression, interactive sensor data retrieval, and structural knowledge discovery, which aim to enhance the reliability, efficiency, and robustness of on-line SHM systems. Adoption of this new concept will enable the design of an on-line SHM system with more uniform data generation and data handling capacity for its subsystems. To examine this concept in the context of vibration-based SHM systems, real sensor data from an on-line SHM system comprising a scaled steel bridge structure and an on-line data acquisition system with remote data access was used in this study. Vibration test results clearly demonstrated the prominent performance characteristics of the proposed integrated SHM system including rapid data access, interactive data retrieval and knowledge discovery of structural conditions on a global level.

  19. Damage detection with streamlined structural health monitoring data.

    Science.gov (United States)

    Li, Jian; Deng, Jun; Xie, Weizhi

    2015-04-15

    The huge amounts of sensor data generated by large scale sensor networks in on-line structural health monitoring (SHM) systems often overwhelms the systems' capacity for data transmission and analysis. This paper presents a new concept for an integrated SHM system in which a streamlined data flow is used as a unifying thread to integrate the individual components of on-line SHM systems. Such an integrated SHM system has a few desirable functionalities including embedded sensor data compression, interactive sensor data retrieval, and structural knowledge discovery, which aim to enhance the reliability, efficiency, and robustness of on-line SHM systems. Adoption of this new concept will enable the design of an on-line SHM system with more uniform data generation and data handling capacity for its subsystems. To examine this concept in the context of vibration-based SHM systems, real sensor data from an on-line SHM system comprising a scaled steel bridge structure and an on-line data acquisition system with remote data access was used in this study. Vibration test results clearly demonstrated the prominent performance characteristics of the proposed integrated SHM system including rapid data access, interactive data retrieval and knowledge discovery of structural conditions on a global level.

  20. Case studies in geographic information systems for environmental streamlining

    Science.gov (United States)

    2012-05-31

    This 2012 summary report addresses the current use of geographic information systems (GIS) and related technologies by State Departments of Transportation (DOTs) for environmental streamlining and stewardship, particularly in relation to the National...

  1. Rise, stagnation, and rise of Danish women's life expectancy

    DEFF Research Database (Denmark)

    Lindahl-Jacobsen, Rune; Rau, Roland; Jeune, Bernard

    2016-01-01

    Health conditions change from year to year, with a general tendency in many countries for improvement. These conditions also change from one birth cohort to another: some generations suffer more adverse events in childhood, smoke more heavily, eat poorer diets, etc., than generations born earlier...... favor forecasts that hinge on cohort differences. We use a combination of age decomposition and exchange of survival probabilities between countries to study the remarkable recent history of female life expectancy in Denmark, a saga of rising, stagnating, and now again rising lifespans. The gap between...... female life expectancy in Denmark vs. Sweden grew to 3.5 y in the period 1975-2000. When we assumed that Danish women born 1915-1945 had the same survival probabilities as Swedish women, the gap remained small and roughly constant. Hence, the lower Danish life expectancy is caused by these cohorts...

  2. Impeding hohlraum plasma stagnation in inertial-confinement fusion.

    Science.gov (United States)

    Li, C K; Séguin, F H; Frenje, J A; Rosenberg, M J; Rinderknecht, H G; Zylstra, A B; Petrasso, R D; Amendt, P A; Landen, O L; Mackinnon, A J; Town, R P J; Wilks, S C; Betti, R; Meyerhofer, D D; Soures, J M; Hund, J; Kilkenny, J D; Nikroo, A

    2012-01-13

    This Letter reports the first time-gated proton radiography of the spatial structure and temporal evolution of how the fill gas compresses the wall blowoff, inhibits plasma jet formation, and impedes plasma stagnation in the hohlraum interior. The potential roles of spontaneously generated electric and magnetic fields in the hohlraum dynamics and capsule implosion are discussed. It is shown that interpenetration of the two materials could result from the classical Rayleigh-Taylor instability occurring as the lighter, decelerating ionized fill gas pushes against the heavier, expanding gold wall blowoff. This experiment showed new observations of the effects of the fill gas on x-ray driven implosions, and an improved understanding of these results could impact the ongoing ignition experiments at the National Ignition Facility.

  3. Expansionary economic effects of energy conversion under stagnation

    International Nuclear Information System (INIS)

    Ono, Yoshiyasu

    2013-01-01

    After the Fukushima disaster, energy conversion such as nuclear power phaseout and deployment of renewable energy or survival of nuclear power had been actively argued pro and con. Both sides admitted extra costs were needed but their economic effects would be contrary dependent on business state. Under better economy, extra costs would be actual burden of total economy. Under stagnation as was long in Japan at present, extra costs brought about expansion of employment and economy with simulated consumption increase. Industry conversion would occur such industry intensively using power would depreciate and energy conserved industry would grow. Difference of power use intensity between industries made difficult in energy conversion because present Japanese industry constitution was mostly formed based on cheap power cost for industry use. Even taking account of international competition, the same would be true by adjusting finance balance sheet and currency exchange rate. (T. Tanaka)

  4. Slab Penetration vs. Slab Stagnation: Mantle Reflectors as an Indicator

    Science.gov (United States)

    Okeler, A.; Gu, Y. J.; Schultz, R.; Contenti, S. M.

    2011-12-01

    Subducting oceanic lithosphere along convergent margins may stagnate near the base of the upper mantle or penetrate into the lower mantle. These dynamic processes cause extensive thermal and compositional variations, which can be observed in terms of impedance contrast (reflectivity) and topography of mantle transition zone (MTZ) discontinuities, i.e., 410- and 660-km discontinuities. In this study, we utilize ~ 15000 surface-reflected shear waves (SS) and their precursory arrivals (S410S and S660S) to analyze subduction related deformations on mantle reflectivity structure. We apply pre-stack, time-to-depth migration technique to SS precursors, and move weak underside reflections using PREM-predicted travel-time curves. Common Mid-point gathers are formed to investigate structure under the western Pacific, south America, and Mediterranean convergent boundaries. In general, mantle reflectivity structures are consistent with previous seismic tomography models. In regions of slab penetration (e.g., southern Kurile arc, Aegean Sea), our results show 1) a substantial decrease in S660S amplitude, and 2) strong lower mantle reflector(s) at ~ 900 km depth. These reflective structures are supported by zones of high P and S velocities extending into the lower mantle. Our 1-D synthetic simulations suggest that the decreasing S660S amplitudes are, at least partially, associated with shear wave defocusing due to changes in reflector depth (by ±20 km) within averaging bin. Assuming a ~500 km wide averaging area, a dipping reflector with 6-8 % slope can reduce the amplitude of a SS precursor by ~50%. On the other hand, broad depressions with strong impedance contrast at the base of the MTZ characterize the regions of slab stagnation, such as beneath the Tyrrhenian Sea and northeastern China. For the latter region, substantial topography on the 660-km discontinuity west of the Wadati-Benioff zone suggests that the stagnant part of the Pacific plate across Honshu arc is not

  5. Streamlined Modeling for Characterizing Spacecraft Anomalous Behavior

    Science.gov (United States)

    Klem, B.; Swann, D.

    2011-09-01

    Anomalous behavior of on-orbit spacecraft can often be detected using passive, remote sensors which measure electro-optical signatures that vary in time and spectral content. Analysts responsible for assessing spacecraft operational status and detecting detrimental anomalies using non-resolved imaging sensors are often presented with various sensing and identification issues. Modeling and measuring spacecraft self emission and reflected radiant intensity when the radiation patterns exhibit a time varying reflective glint superimposed on an underlying diffuse signal contribute to assessment of spacecraft behavior in two ways: (1) providing information on body component orientation and attitude; and, (2) detecting changes in surface material properties due to the space environment. Simple convex and cube-shaped spacecraft, designed to operate without protruding solar panel appendages, may require an enhanced level of preflight characterization to support interpretation of the various physical effects observed during on-orbit monitoring. This paper describes selected portions of the signature database generated using streamlined signature modeling and simulations of basic geometry shapes apparent to non-imaging sensors. With this database, summarization of key observable features for such shapes as spheres, cylinders, flat plates, cones, and cubes in specific spectral bands that include the visible, mid wave, and long wave infrared provide the analyst with input to the decision process algorithms contained in the overall sensing and identification architectures. The models typically utilize baseline materials such as Kapton, paints, aluminum surface end plates, and radiators, along with solar cell representations covering the cylindrical and side portions of the spacecraft. Multiple space and ground-based sensors are assumed to be located at key locations to describe the comprehensive multi-viewing aspect scenarios that can result in significant specular reflection

  6. Using 1D theory to understand 3D stagnation of a wire-array Z pinch in the absence of radiation

    Science.gov (United States)

    Yu, Edmund

    2015-11-01

    Many high-energy-density systems implode towards the axis of symmetry, where it collides on itself, forming a hot plasma. However, experiments show these imploding plasmas develop three-dimensional (3D) structures. As a result, the plasma cannot completely dissipate its kinetic energy at stagnation, instead retaining significant 3D flow. A useful tool for understanding the effects of this residual flow is 3D simulation, but the amount and complexity of information can be daunting. To address this problem, we explore the connection between 3D simulation and one-dimensional (1D) theory. Such a connection, if it exists, is mutually beneficial: 1D theory can provide a clear picture of the underlying dynamics of 3D stagnation. On the other hand, deviations between theory and simulation suggest how 1D theory must be modified to account for 3D effects. In this work, we focus on a 3D, magnetohydrodynamic simulation of a compact wire-array Z pinch. To provide a simpler background against which to test our ideas, we artificially turn off radiation during the stagnation phase. Examination of the initial accumulation of mass on axis reveals oblique collision between jets, shock accretion, and vortex formation. Despite evidence for shock-dominated stagnation, a 1D shockless stagnation solution is more appropriate for describing the global dynamics, in that it reproduces the increase of on-axis density with time. However, the 1D solution must be modified to account for 3D effects: the flows suggest enhanced thermal transport as well as centrifugal force. Upon reaching peak compression, the stagnation transitions to a second phase, in which the high-pressure core on axis expands outward into the remaining imploding plasma. During this phase, a 1D shock solution describes the growth of the shock accretion region, as well as the decrease of on-axis density with time. However, the effect of 3D flows is still present: the on-axis temperature does not cool during expansion, which

  7. The role of streamline curvature in sand dune dynamics: evidence from field and wind tunnel measurements

    Science.gov (United States)

    Wiggs, Giles F. S.; Livingstone, Ian; Warren, Andrew

    1996-09-01

    Field measurements on an unvegetated, 10 m high barchan dune in Oman are compared with measurements over a 1:200 scale fixed model in a wind tunnel. Both the field and wind tunnel data demonstrate similar patterns of wind and shear velocity over the dune, confirming significant flow deceleration upwind of and at the toe of the dune, acceleration of flow up the windward slope, and deceleration between the crest and brink. This pattern, including the widely reported upwind reduction in shear velocity, reflects observations of previous studies. Such a reduction in shear velocity upwind of the dune should result in a reduction in sand transport and subsequent sand deposition. This is not observed in the field. Wind tunnel modelling using a near-surface pulse-wire probe suggests that the field method of shear velocity derivation is inadequate. The wind tunnel results exhibit no reduction in shear velocity upwind of or at the toe of the dune. Evidence provided by Reynolds stress profiles and turbulence intensities measured in the wind tunnel suggest that this maintenance of upwind shear stress may be a result of concave (unstable) streamline curvature. These additional surface stresses are not recorded by the techniques used in the field measurements. Using the occurrence of streamline curvature as a starting point, a new 2-D model of dune dynamics is deduced. This model relies on the establishment of an equilibrium between windward slope morphology, surface stresses induced by streamline curvature, and streamwise acceleration. Adopting the criteria that concave streamline curvature and streamwise acceleration both increase surface shear stress, whereas convex streamline curvature and deceleration have the opposite effect, the relationships between form and process are investigated in each of three morphologically distinct zones: the upwind interdune and concave toe region of the dune, the convex portion of the windward slope, and the crest-brink region. The

  8. Experimental and Numerical Investigation of Flow Structures around Cylindrical Bluff Bodies

    Directory of Open Access Journals (Sweden)

    Yagmur Sercan

    2015-01-01

    Full Text Available The understanding and quantitative prediction of velocity and pressure fluctuations in turbulent flows around such bluff bodies have been evolving over the years. The main aim of the present work is to investigate experimentally and numerically the flow field in the wake region of different bluff bodies such as circular, square and triangle cross section cylinders placed horizontally perpendicular to the uniform flow. The experimental studies were performed by Particle Image Velocimetry (PIV method in an open water channel at Reynolds numbers 5000 and 10000 defined according to the characteristic lengths of the cylinders in the facilities of Selcuk University of Advanced Technology Research and Application Center in Turkey. The experimental results are compared to the numerical results obtained by means of transient simulation with LES turbulence model of ANSYS-Fluent Software. It is shown that the numerical and experimental results have a good agreement in respect of the instantaneous and time-averaged flow field patterns of vorticity, velocity component streamwise direction and streamline topology. In addition, drag coefficient of the geometries were also numerically calculated. For all geometries the wake length in x and y directions and size of the foci of the streamlines are decreasing by increasing Reynolds numbers in time-averaged results. The time-averaged flow patterns of both experimental and numerical results have considerable symmetry with respect to the centerline of each cylinder. Contours of the time-averaged stream wise velocity for Re=10000 demonstrate that the stagnation point around the symmetry plane moves further upstream for all cylinders in accordance with Re=5000. The maximum drag coefficient value was yielded for the square cross-section cylinder as 1.78 due to the sharp-edged geometry.

  9. An automatic, stagnation point based algorithm for the delineation of Wellhead Protection Areas

    Science.gov (United States)

    Tosco, Tiziana; Sethi, Rajandrea; di Molfetta, Antonio

    2008-07-01

    Time-related capture areas are usually delineated using the backward particle tracking method, releasing circles of equally spaced particles around each well. In this way, an accurate delineation often requires both a very high number of particles and a manual capture zone encirclement. The aim of this work was to propose an Automatic Protection Area (APA) delineation algorithm, which can be coupled with any model of flow and particle tracking. The computational time is here reduced, thanks to the use of a limited number of nonequally spaced particles. The particle starting positions are determined coupling forward particle tracking from the stagnation point, and backward particle tracking from the pumping well. The pathlines are postprocessed for a completely automatic delineation of closed perimeters of time-related capture zones. The APA algorithm was tested for a two-dimensional geometry, in homogeneous and nonhomogeneous aquifers, steady state flow conditions, single and multiple wells. Results show that the APA algorithm is robust and able to automatically and accurately reconstruct protection areas with a very small number of particles, also in complex scenarios.

  10. Self-Generated Magnetic Fields in Stagnation-Phase ICF Implosions

    Science.gov (United States)

    Walsh, Christopher; Chittenden, Jeremy; McGlinchey, Kristopher; Niasse, Nicolas

    2016-10-01

    3-D extended-MHD simulations of the stagnation phase of an ICF implosion are presented, showing significant self-generated magnetic fields (1000-5000T) due to the Biermann Battery effect. Perturbed hot-spots generate magnetic fields at their edges, as the extremities of hot bubbles are rapidly cooled by the surrounding low temperature fuel, giving non-parallel electron pressure and density gradients. Larger amplitude and higher mode-number perturbations lead to an increased hot-spot surface area and more heat flow, developing greater non-parallel gradients and therefore larger magnetic fields. Due to this, largely perturbed hot-spots can be affected more by magnetic fields, although the accelerated cooling associated with greater deviations from symmetry lowers magnetisation. The Nernst effect advects magnetic field down temperature gradients towards the outer region of the hot-spot, which can also lower the magnetisation of the plasma. In some regions, however, the Nernst velocity is convergent, magnetising the tips of cold fuel spikes, resulting in anisotropic heat-flow and an improvement in energy containment. Low-mode and multi-high-mode simulations are shown, with magnetisations reaching sufficiently high levels in some regions of the hot-spot to suppress thermal conduction to lower than 50% of the unmagnetised case. A quantitative analysis of how this affects the hot-spot energy balance is included.

  11. Assessment of Fuel Analysis Methodology and Fission Product Release for 37-Element Fuel by Using the Latest IST Codes during Stagnation Feeder Break in CANDU

    International Nuclear Information System (INIS)

    Park, Joo Hwan; Jung, Jong Yeob

    2009-09-01

    Feeder break accident is regarded as one of the design basis accident in CANDU reactor which results in a fuel failure. For a particular range of inlet feeder break sizes, the flow in the channel is reduced sufficiently that the fuel and fuel channel integrity can be significantly affected to have damage in the affected channel, while the remainder of the core remains adequately cooled. The flow in the downstream channel can be more or less stagnated due to a balance between pressure at the break on the upstream side and the reverse driving pressure between the break and the downstream end. In the extreme, this can lead to rapid fuel heatup and fuel damage and failure of the fuel channel similar to that associated with a severe channel flow blockage. Such an inlet feeder break scenario is called a stagnation break. In this report, the fuel analysis methodology and the assessment results of fission product inventory and release during the stagnation feeder break are described for conservatively assumed limiting channel. The accident was assumed to be occurred in the refurbished Wolsong unit 1 and the latest safety codes were used in the analysis. Fission product inventories during the steady state were calculated by using ELESTRES-IST 1.2 code. The whole analysis process was carried out by a script file which was programmed by Perl language. The perl script file was programmed to make all ELESTRES input files for each bundle and each ring based on the given power-burnup history and thermal-hydraulic conditions of the limiting channel and to perform the fuel analysis automatically. The fission product release during the transient period of stagnation feeder break was evaluated by applying Gehl model. The amounts of each isotope's release are conservatively evaluated for additional 2 seconds after channel failure. The calculated fission product releases are provided to the following dose assessment as a source term

  12. Turbulent Reynolds stress and quadrant event activity in wind flow over a coastal foredune

    Science.gov (United States)

    Chapman, Connie A.; Walker, Ian J.; Hesp, Patrick A.; Bauer, Bernard O.; Davidson-Arnott, Robin G. D.

    2012-05-01

    Recent research on quasi-instantaneous turbulent kinematic Reynolds stresses (RS, - u'w') and decomposed quadrant event activity (e.g., ejections and sweeps) over dunes in fluvial settings and in wind tunnels has shown that turbulent stresses at the toe of a dune often exceed time-averaged, streamwise shear stress (ρ u * 2) estimates. It is believed that semi-coherent turbulent structures are conveyed toward the bed along concave streamlines in this region and that impact of these structures cause fluctuations in local surface stresses that assist in grain entrainment. This has been hypothesized to explain how sand is supplied to the windward slope through a region of flow stagnation. Toward the crest, surface stress increases and becomes dominated by streamwise accelerations resulting from streamline compression and convexity that suppress vertical motions. High-frequency (32 Hz) measurements of turbulent wind flow from 3-D ultrasonic anemometers are analyzed for oblique onshore flow over a vegetated coastal foredune in Prince Edward Island, Canada. Reynolds stress and quadrant activity distributions varied with height (0.60 m and 1.66 m) and location over the dune. In general, quadrant 2 ejection (u' 0) and quadrant 4 sweep activity (u' > 0, w' 0, w' > 0) and quadrant 3 inward interaction (u' dune and may help to explain sand transport potential and dune maintenance. For example, areas with a high frequency of ejection and sweep activity may have higher rates of sediment entrainment and transport, whereas areas with lower ejection and sweep activity and an increase in outward and inward interactions, which contribute negatively to Reynolds stress generation, may experience a greater potential for deposition. Further research on associations between quadrant event activity and coincident sand transport is required to confirm this hypothesis and the resultant significance of the flow exuberance effect in aeolian dune morphodynamics.

  13. Stagnating Jatropha Biofuel Development in Southwest China: An Institutional Approach

    Directory of Open Access Journals (Sweden)

    Jia Li

    2014-05-01

    Full Text Available Biodiesel from jatropha has been considered as a promising alternative to fossil fuels for some time. Consequently, China started promoting jatropha as one of the options to meet its ever-increasing energy consumption, and the Chinese biodiesel industry also gained interest. However, the excitement of the biofuel industry in jatropha faded after it did not bring about the expected results. This article investigates the stagnation in jatropha development and production for biodiesel in China, using two detailed case studies of jatropha biofuel production in southeast China. It is found that the underdeveloped biodiesel policy and regulation, such as a rather late formulation of standards for biodiesel (especially the B5 and the absence of mandatory targets, is an important reason for hampering jatropha development. Besides that, lack of financial support undermined sustained jatropha planting at the farm level and lack of sustained commitment from state-owned enterprises or private companies over a long time span further contributed to jatropha project’s failure. Better implementation of the rule of law, mandatory blending requirements, hazard insurance, as well as continuous financial support, might improve the continuation of jatropha plantation schemes.

  14. Streamlining of the RELAP5-3D Code

    International Nuclear Information System (INIS)

    Mesina, George L; Hykes, Joshua; Guillen, Donna Post

    2007-01-01

    RELAP5-3D is widely used by the nuclear community to simulate general thermal hydraulic systems and has proven to be so versatile that the spectrum of transient two-phase problems that can be analyzed has increased substantially over time. To accommodate the many new types of problems that are analyzed by RELAP5-3D, both the physics and numerical methods of the code have been continuously improved. In the area of computational methods and mathematical techniques, many upgrades and improvements have been made decrease code run time and increase solution accuracy. These include vectorization, parallelization, use of improved equation solvers for thermal hydraulics and neutron kinetics, and incorporation of improved library utilities. In the area of applied nuclear engineering, expanded capabilities include boron and level tracking models, radiation/conduction enclosure model, feedwater heater and compressor components, fluids and corresponding correlations for modeling Generation IV reactor designs, and coupling to computational fluid dynamics solvers. Ongoing and proposed future developments include improvements to the two-phase pump model, conversion to FORTRAN 90, and coupling to more computer programs. This paper summarizes the general improvements made to RELAP5-3D, with an emphasis on streamlining the code infrastructure for improved maintenance and development. With all these past, present and planned developments, it is necessary to modify the code infrastructure to incorporate modifications in a consistent and maintainable manner. Modifying a complex code such as RELAP5-3D to incorporate new models, upgrade numerics, and optimize existing code becomes more difficult as the code grows larger. The difficulty of this as well as the chance of introducing errors is significantly reduced when the code is structured. To streamline the code into a structured program, a commercial restructuring tool, FOR( ) STRUCT, was applied to the RELAP5-3D source files. The

  15. Comparison of Flow Characteristics of Different Sphere Geometries Under the Free Surface Effect

    Directory of Open Access Journals (Sweden)

    Sahin B.

    2013-04-01

    Full Text Available Comparison of the experimental results of turbulent flow structures between a smooth sphere and a sphere with a vent hole, roughened, and o-ring is presented in the presence of a free-surface. Dye visualization and particle image velocimetry (PIV techniques were performed to examine effects of passive control methods on the sphere wake for Reynolds number Re = 5000 based on the sphere diameter with a 42.5mm in an open water channel. Instantaneous and time-averaged flow patterns in the wake region of the sphere were examined from point of flow physics for the different sphere locations in the range of 0≤h/D≤2.0 where h was the space between the top point of the sphere and the free surface. The ratio of ventilation hole to sphere diameter was 0.15, o-ring was located at 55° with a 2 mm from front stagnation point of the sphere and roughened surface was formed by means of totally 410 circular holes with a 3 mm diameter and around 2 mm depth in an equilateral triangle arrangement. The flow characteristics of instantaneous velocity vectors, vorticity contours, time-averaged streamline patterns, Reynolds stress correlations and streamwise and cross-stream velocity fluctuations for both the smooth and passively controlled sphere were interpreted.

  16. Structure and temperature distribution of a stagnation-point Diesel spray premixed flame

    International Nuclear Information System (INIS)

    Lin, J.-C.; Lin, Ta-Hui

    2005-01-01

    We experimentally examine the flow and flame characteristics of a stagnation point premixed flame influenced by Diesel sprays. In the experiment, distributions of drop size, drop axial velocity and its fluctuation as well as the gas phase temperature are measured by using the phase-doppler particle analyzer and a thin thermocouple. As might be expected, similar to the gasoline spray flame, the partially prevaporized Diesel spray flame is composed of a weak blue flame zone, indicating the burning of methane fuel, and a strongly luminous zone containing many bright yellow lines showing the passages of burning Diesel drops. It is found that the axial temperature profiles at various radial positions consist of an upstream preheat region, a maximum temperature downstream of the blue flame and a downstream region with a declined temperature curve because of the heat loss to the quartz plate. The SMD of the drops increases from the upstream preheat region to a maximum near the blue flame and then decreases in the downstream burning zone. Along the axial position, the drops are decelerated in front of the flame but accelerated when passing through the blue flame. It is also interesting to note that the radial distributions of SMD and number density of drops in the upstream region are mainly influenced by small drops flowing outward, since the upstream vaporization of Diesel drops is very limited; while those in the downstream region should be influenced by both small drops flowing outward and Diesel drops burning. From the experimental observations, there are impinging and bouncing of Diesel drops downstream of the spray flame near the quartz plate, resulting in a small amount of soot and carbon deposits on the wall. These interesting phenomena will be reported in the near future

  17. 48 CFR 12.602 - Streamlined evaluation of offers.

    Science.gov (United States)

    2010-10-01

    ... offers. 12.602 Section 12.602 Federal Acquisition Regulations System FEDERAL ACQUISITION REGULATION... for Commercial Items 12.602 Streamlined evaluation of offers. (a) When evaluation factors are used... evaluation factors. (b) Offers shall be evaluated in accordance with the criteria contained in the...

  18. Application-Tailored I/O with Streamline

    NARCIS (Netherlands)

    de Bruijn, W.J.; Bos, H.J.; Bal, H.E.

    2011-01-01

    Streamline is a stream-based OS communication subsystem that spans from peripheral hardware to userspace processes. It improves performance of I/O-bound applications (such as webservers and streaming media applications) by constructing tailor-made I/O paths through the operating system for each

  19. Safe, Non-Corrosive Dielectric Fluid for Stagnating Radiator Thermal Control System, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Paragon proposes to develop a single-loop, non-toxic, stagnating active pumped loop thermal control design for NASA's Orion or Lunar Surface Access Module (LSAM)...

  20. Side Flow Effect on Surface Generation in Nano Cutting.

    Science.gov (United States)

    Xu, Feifei; Fang, Fengzhou; Zhang, Xiaodong

    2017-12-01

    The side flow of material in nano cutting is one of the most important factors that deteriorate the machined surface quality. The effects of the crystallographic orientation, feed, and the cutting tool geometry, including tool edge radius, rake angle and inclination angle, on the side flow are investigated employing molecular dynamics simulation. The results show that the stagnation region is formed in front of tool edge and it is characterized by the stagnation radius R s and stagnation height h s . The side flow is formed because the material at or under the stagnation region is extruded by the tool edge to flow to the side of the tool edge. Higher stagnation height would increase the size of the side flow. The anisotropic nature of the material which partly determines the stagnation region also influences the side flow due to the different deformation mechanism under the action of the tool edge. At different cutting directions, the size of the side flow has a great difference which would finally affect the machined surface quality. The cutting directions of {100} , {110} , and {110}  are beneficial to obtain a better surface quality with small side flow. Besides that, the side flow could be suppressed by reducing the feed and optimizing the cutting tool geometry. Cutting tool with small edge radius, large positive rake angle, and inclination angle would decrease the side flow and consequently improve the machined surface quality.

  1. An Evaluation of the Acquisition Streamlining Methods at the Fleet and Industrial Supply Center Pearl Harbor Hawaii

    National Research Council Canada - National Science Library

    Henry, Mark

    1999-01-01

    ...) Pearl Harbor's implementation of acquisition streamlining initiatives and recommends viable methods of streamlining the acquisition process at FISC Pearl Harbor and other Naval Supply Systems Command...

  2. Streamlining: Reducing costs and increasing STS operations effectiveness

    Science.gov (United States)

    Petersburg, R. K.

    1985-01-01

    The development of streamlining as a concept, its inclusion in the space transportation system engineering and operations support (STSEOS) contract, and how it serves as an incentive to management and technical support personnel is discussed. The mechanics of encouraging and processing streamlining suggestions, reviews, feedback to submitters, recognition, and how individual employee performance evaluations are used to motivation are discussed. Several items that were implemented are mentioned. Information reported and the methodology of determining estimated dollar savings are outlined. The overall effect of this activity on the ability of the McDonnell Douglas flight preparation and mission operations team to support a rapidly increasing flight rate without a proportional increase in cost is illustrated.

  3. Zephyr: A secure Internet process to streamline engineering

    Energy Technology Data Exchange (ETDEWEB)

    Jordan, C.W.; Niven, W.A.; Cavitt, R.E. [and others

    1998-05-12

    Lawrence Livermore National Laboratory (LLNL) is implementing an Internet-based process pilot called `Zephyr` to streamline engineering and commerce using the Internet. Major benefits have accrued by using Zephyr in facilitating industrial collaboration, speeding the engineering development cycle, reducing procurement time, and lowering overall costs. Programs at LLNL are potentializing the efficiencies introduced since implementing Zephyr. Zephyr`s pilot functionality is undergoing full integration with Business Systems, Finance, and Vendors to support major programs at the Laboratory.

  4. A Streamlined Artificial Variable Free Version of Simplex Method

    OpenAIRE

    Inayatullah, Syed; Touheed, Nasir; Imtiaz, Muhammad

    2015-01-01

    This paper proposes a streamlined form of simplex method which provides some great benefits over traditional simplex method. For instance, it does not need any kind of artificial variables or artificial constraints; it could start with any feasible or infeasible basis of an LP. This method follows the same pivoting sequence as of simplex phase 1 without showing any explicit description of artificial variables which also makes it space efficient. Later in this paper, a dual version of the new ...

  5. Effect of ablation geometry on the formation of stagnation layer in laterally colliding plasmas

    International Nuclear Information System (INIS)

    Mondal, Alamgir; Singh, Rajesh K.; Kumar, Ajai

    2015-01-01

    Interaction between two parallel propagating plasma plumes have been investigated in two different ablation schemes e.g. laser-blow-off (LBO) of thin film and conventional laser ablation (LPP). Fast imagine technique is used to study the dynamical and geometrical aspect of seed plasmas and induced stagnation layer in between the two expanding seed plasmas. Interaction between the energetic particles, coming from the seed plasmas are responsible for formation of stagnation layer. It has been found that geometrical shape, size, kinetic energy and divergence of plasma plumes are highly dependent on the ablation geometry. These variations in seed plasmas initiate the significant differences in the stagnation layer formed by LBO and LPP geometry. In this presentation, characteristic feature of stagnation layer which includes density, initiation time, emissive life time and geometry in both LBO and LPP geometry are briefly discussed. A comparative study of present results suggests that the plume composition and directionality of seed plasma play crucial role in mechanistic aspect of stagnation layer. (author)

  6. Implications of the stagnation line model for energy input through the dayside magnetopause

    International Nuclear Information System (INIS)

    Pudovkin, M.I.; Semenov, V.S.; Heyn, M.F.; Biernat, H.K.

    1986-01-01

    Based on the formation of a stagnation line at the magnetopause the electromagnetic energy transport from the solar wind into the dayside magnetosphere is analyzed. The resulting energy flux is analyzed. The resulting energy flux is proportional to v/sub infinity/B/sub infinity/sin 2 (theta/sub infinity/-phi/sub infinity/), where v/sub infinity/ and B/sub infinity/ are the solar wind speed and magnetic field and theta/sub infinity/-phi/sub s/infinity is the angle between the IMF and the stagnation line projected into the interplanetary space. A stagnation line parallel to the separator gives approximately the sin 4 (theta/sub infinity//2) energy flux dependence of Akasofu's epsilon-index

  7. Wage Dispersion, Public Sector Wages and the Stagnating Danish Gender Wage Gap

    DEFF Research Database (Denmark)

    Gupta, Nabanita Datta; Oaxaca, Ronald L.; Smith, Nina

    1998-01-01

    The gender wage gap in Denmark has virtually stagnated since the early 70s. This study examines whether this stagnation is mainly due to a changing wage dispersion or to changing prices on observed and unobserved skills. Since about half the female labour force is employed in the public sector....... These techniques are applied to a sample of Danish wage earners in the period 1983-94. The decomposition results suggest different explanations behind the stagnation of the gender wage gap in the public and private sectors. The development in average public sector wages is calculated assuming observed......, the impact of the changing wage structure between the public and private sectors is investigated. The analysis is based on the Juhn-Murphy-Pierce decomposition applied to a pooled wage regression model. The equivalence between the former and the Oaxaca-Ransom generalized wage decomposition is established...

  8. Stagnation and Storage of Strongly Depleted Melts in Slow-Ultraslow Spreading Oceans: Evidence from the Ligurian Tethys

    Science.gov (United States)

    Piccardo, Giovanni; Guarnieri, Luisa; Padovano, Matteo

    2013-04-01

    Our studies of Alpine-Apennine ophiolite massifs (i.e., Lanzo, Voltri, Ligurides, Corsica) show that the Jurassic Ligurian Tethys oceanic basin was a slow-ultraslow spreading basin, characterized by the exposures on the seafloor of mantle peridotites with extreme compositional variability. The large majority of these peridotites are made of depleted spinel harzburgites and plagioclase peridotites. The former are interpreted as reactive peridotites formed by the reactive percolation of under-saturated, strongly trace element depleted asthenospheric melts migrated by porous flow through the mantle lithosphere. The latter are considered as refertilized peridotites formed by peridotite impregnation by percolated silica-saturated, strongly trace element depleted melts. Strongly depleted melts were produced as low-degrees, single melt increments by near fractional melting of the passively upwelling asthenosphere during the rifting stage of the basin. They escaped single melt increment aggregation, migrated isolated through the mantle lithosphere by reactive porous or channeled flow before oceanic opening, and were transformed into silica-saturated derivative liquids that underwent entrapment and stagnation in the shallow mantle lithosphere forming plagioclase-enriched peridotites. Widespread small bodies of strongly depleted gabbro-norites testify for the local coalescence of these derivative liquids. These melts never reached the surface (i.e., the hidden magmatism), since lavas with their composition have never been found in the basin. Subsequently, aggregated MORB melts upwelled within replacive dunite channels (as evidenced by composition of magmatic clinopyroxenes in dunites), intruded at shallow levels as olivine gabbro bodies and extruded as basaltic lavas, to form the crustal rocks of the oceanic lithosphere (i.e., the oceanic magmatism). Km-scale bodies of MORB olivine gabbros were intruded into the plagioclase-enriched peridotites, which were formed in the

  9. Analytical Work in Support of the Design and Operation of Two Dimensional Self Streamlining Test Sections

    Science.gov (United States)

    Judd, M.; Wolf, S. W. D.; Goodyer, M. J.

    1976-01-01

    A method has been developed for accurately computing the imaginary flow fields outside a flexible walled test section, applicable to lifting and non-lifting models. The tolerances in the setting of the flexible walls introduce only small levels of aerodynamic interference at the model. While it is not possible to apply corrections for the interference effects, they may be reduced by improving the setting accuracy of the portions of wall immediately above and below the model. Interference effects of the truncation of the length of the streamlined portion of a test section are brought to an acceptably small level by the use of a suitably long test section with the model placed centrally.

  10. Streamlining interventional radiology admissions: The role of the interventional radiology clinic and physician's assistant

    International Nuclear Information System (INIS)

    White, R.I. Jr.; Rizer, D.M.; Shuman, K.; White, E.J.; Adams, P.; Doyle, K.; Kinnison, M.

    1987-01-01

    During a 5-year period (1982-1987), 376 patients were admitted to an interventional radiology service where they were managed by the senior physician and interventional radiology fellows. Sixty-eight percent of patients were admitted for angioplasty and 32% for elective embolotherapy/diagnostic angiography. A one-half-day, twice weekly interventional radiology clinic and employment of a physician's assistant who performed preadmission history and physicals and wrote orders accounted, in part, for a decrease in hospital stay length from 3.74 days (1982-1983) to 2.41 days (1986-1987). The authors conclude that use of the clinic and the physician's assistant streamlines patient flow and the admitting process and is partially responsible for a decreased length of stay for patients admitted to an interventional radiology service

  11. Drag Reduction CFD Simulations and Flow Visualization of Light Vehicle-Trailer Systems

    Science.gov (United States)

    Sigurdson, Lorenz; Boyer, Henry; Lange, Carlos F.

    2016-11-01

    Experiments and CFD were performed to study the effect a deflector had on the flow and drag force associated with a 2010 F-150 truck and cargo trailer Light Vehicle-Trailer System (LVTS). Image Correlation Velocimetry (ICV) on smokewire streaklines measured the velocity field on the model mid-plane. CFD estimated the drag reduction as 13% at a Re of 14,900 with a moving ground-plane, and 17% without. Experiments suggested that the low Re does not diminish the full-scale relevance of the drag reduction results. One low Re effect was the presence of a separation bubble on the hood of the tow vehicle whose size reduced with an increase in Re. Three other characteristic flow patterns were identified: separation off the lead vehicle cab, stagnation of the free-stream on the trailer face for the no-deflector case, and subsequent separation at the trailer front corner. Comparisons of the ICV and CFD results with no deflector indicated good agreement in the direction of the velocity vectors, and the smoke streaklines and CFD streamlines also agreed well. However, for the deflector case, the CFD found an entirely different topological solution absent in the experiment. A pair of vertically-oriented mid-plane vortices were wrapped around the front of the trailer. Support from the Canadian Natural Sciences and Engineering Research Council Grant 41747 is gratefully acknowledged.

  12. Advection-diffusion model for normal grain growth and the stagnation of normal grain growth in thin films

    International Nuclear Information System (INIS)

    Lou, C.

    2002-01-01

    An advection-diffusion model has been set up to describe normal grain growth. In this model grains are divided into different groups according to their topological classes (number of sides of a grain). Topological transformations are modelled by advective and diffusive flows governed by advective and diffusive coefficients respectively, which are assumed to be proportional to topological classes. The ordinary differential equations governing self-similar time-independent grain size distribution can be derived analytically from continuity equations. It is proved that the time-independent distributions obtained by solving the ordinary differential equations have the same form as the time-dependent distributions obtained by solving the continuity equations. The advection-diffusion model is extended to describe the stagnation of normal grain growth in thin films. Grain boundary grooving prevents grain boundaries from moving, and the correlation between neighbouring grains accelerates the stagnation of normal grain growth. After introducing grain boundary grooving and the correlation between neighbouring grains into the model, the grain size distribution is close to a lognormal distribution, which is usually found in experiments. A vertex computer simulation of normal grain growth has also been carried out to make a cross comparison with the advection-diffusion model. The result from the simulation did not verify the assumption that the advective and diffusive coefficients are proportional to topological classes. Instead, we have observed that topological transformations usually occur on certain topological classes. This suggests that the advection-diffusion model can be improved by making a more realistic assumption on topological transformations. (author)

  13. Turbulent shear flow downstream of a sphere with and without an o-ring located over a plane boundary

    Directory of Open Access Journals (Sweden)

    Sahin Besir

    2012-04-01

    Full Text Available Flow-structure interaction of separated shear flow from the sphere and a flat plate was investigated by using dye visualization and the particle image velocimetry technique. Later, a passive control method was applied with 2mm oring located on the sphere surface at 55° from front stagnation point. The experiments were carried out in open water channel for Reynolds number value of Re=5000. Flow characteristics have been examined in terms of the 2-D instantaneous and time-averaged velocity vectors, patterns of vorticity, streamlines, rms of velocity fluctuations and Reynolds stress variations and discussed from the point of flow physics, vortex formation, lengths of large-scale Karman Vortex Streets and Kelvin-Helmholtz vortices depending on the sphere locations over the flat plate. It is demonstrated that the gap flow occurring between the sphere bottom point and the flat plate surface has very high scouring effect until h/d=0.25 and then unsymmetrical flow structure of the wake region keeps up to h/D=1.0 for smooth sphere. For the sphere with o-ring, the wake flow structure becomes symmetrical at smaller gap ratios and reattachment point on the flat plate surface occurs earlier. Moreover, o-ring on the sphere diminishes peak magnitudes of the flow characteristics and thus it is expected that the flow-induced forces will be lessened both on the sphere and flat plate surface. Vortex formation lengths and maximum value occurring points become closer locations to the rear surface of the sphere with o-ring.

  14. Filaments in curved streamlines: rapid formation of Staphylococcus aureus biofilm streamers

    International Nuclear Information System (INIS)

    Kevin Kim, Minyoung; Drescher, Knut; Shun Pak, On; Stone, Howard A; Bassler, Bonnie L

    2014-01-01

    Biofilms are surface-associated conglomerates of bacteria that are highly resistant to antibiotics. These bacterial communities can cause chronic infections in humans by colonizing, for example, medical implants, heart valves, or lungs. Staphylococcus aureus, a notorious human pathogen, causes some of the most common biofilm-related infections. Despite the clinical importance of S. aureus biofilms, it remains mostly unknown how physical effects, in particular flow, and surface structure influence biofilm dynamics. Here we use model microfluidic systems to investigate how environmental factors, such as surface geometry, surface chemistry, and fluid flow affect biofilm development of S. aureus. We discovered that S. aureus rapidly forms flow-induced, filamentous biofilm streamers, and furthermore if surfaces are coated with human blood plasma, streamers appear within minutes and clog the channels more rapidly than if the channels are uncoated. To understand how biofilm streamer filaments reorient in flows with curved streamlines to bridge the distances between corners, we developed a mathematical model based on resistive force theory of slender filaments. Understanding physical aspects of biofilm formation of S. aureus may lead to new approaches for interrupting biofilm formation of this pathogen. (paper)

  15. Streamlining digital signal processing a tricks of the trade guidebook

    CERN Document Server

    2012-01-01

    Streamlining Digital Signal Processing, Second Edition, presents recent advances in DSP that simplify or increase the computational speed of common signal processing operations and provides practical, real-world tips and tricks not covered in conventional DSP textbooks. It offers new implementations of digital filter design, spectrum analysis, signal generation, high-speed function approximation, and various other DSP functions. It provides:Great tips, tricks of the trade, secrets, practical shortcuts, and clever engineering solutions from seasoned signal processing professionalsAn assortment.

  16. A streamlined ribosome profiling protocol for the characterization of microorganisms

    DEFF Research Database (Denmark)

    Latif, Haythem; Szubin, Richard; Tan, Justin

    2015-01-01

    Ribosome profiling is a powerful tool for characterizing in vivo protein translation at the genome scale, with multiple applications ranging from detailed molecular mechanisms to systems-level predictive modeling. Though highly effective, this intricate technique has yet to become widely used...... in the microbial research community. Here we present a streamlined ribosome profiling protocol with reduced barriers to entry for microbial characterization studies. Our approach provides simplified alternatives during harvest, lysis, and recovery of monosomes and also eliminates several time-consuming steps...

  17. Streamlined library programming how to improve services and cut costs

    CERN Document Server

    Porter-Reynolds, Daisy

    2014-01-01

    In their roles as community centers, public libraries offer many innovative and appealing programs; but under current budget cuts, library resources are stretched thin. With slashed budgets and limited staff hours, what can libraries do to best serve their publics? This how-to guide provides strategies for streamlining library programming in public libraries while simultaneously maintaining-or even improving-quality delivery. The wide variety of principles and techniques described can be applied on a selective basis to libraries of all sizes. Based upon the author's own extensive experience as

  18. Invalidating stagnation theory for family owned businesses : comparing family-to-family and third party ownership transfers

    NARCIS (Netherlands)

    Alija Ibrahimovic; Lex van Teeffelen; Roger Heaver

    2015-01-01

    Miller, Le Breton-Miller and Scholnick (2008) summarize and discuss two major perspectives constructed from the literature on family owned businesses (FOBs): stewardship and stagnation theory. In this paper the stagnation theory is being put to the test on Dutch small/medium enterprises (SMEs).

  19. Growth or stagnation in pre-industrial Britain? A revealed income growth approach

    DEFF Research Database (Denmark)

    Groth, Christian; Persson, Karl Gunnar

    2016-01-01

    The extent of growth in pre-industrial Europe in general and in Britain in particular has attracted intense scholarly focus. Growth or Malthusian stagnation? No consensus has evolved. Reconstructions of national income from 1300 and up to the Industrial Revolution come to opposing conclusions...

  20. Prediction and experimental validation of stagnation temperature attained by a solar cooker of hot box type

    Energy Technology Data Exchange (ETDEWEB)

    Narasimha Rao, A. V; Srikrishna, D. V. N [Warangal (India)

    2000-07-01

    A hot box type solar cooker, having double glass covers and a plane mirror reflector, is tested for stagnation temperature. A computer code is developed based on the analytical model proposed by Vaishya et. al. The global and beam components of solar radiation measured at Warangal are made use to predict the stagnation temperature of the cooker. The observed values of stagnation temperature at Warangal are compared with those of predicted values. A good agreement of the measured and observed values of the stagnation temperature is observed during the afternoon period. The lag in the observed values during the forenoon may be due to thermal inertia of the cooker. [Spanish] Se probo una estufa solar de tipo caja caliente con cubiertas dobles de vidrio y un espejo reflector plano para medir la temperatura de estancamiento. Se desarrollo un codigo de computacion basado en el modelo analitico propuesto por Vaishya et. al. Los componentes de la radiacion solar globales y de rayo medidos en Warangal se usan para predecir la temperatura de estancamiento de la estufa. Los valores observados de la temperatura de estancamiento en Warangal se comparan con los valores predichos. Se aprecia una buena concidencia de los valores medidos y observados de la temperatura de estancamiento durante el periodo de la tarde. El retraso de los valores observados durante la manana puede ser debido a la inercia termica de la estufa.

  1. What Explains the Stagnation of Female Labor Force Participation in Urban India?

    NARCIS (Netherlands)

    Klasen, S.; Pieters, J.

    2015-01-01

    Female labor force participation rates in urban India between 1987 and 2011 are surprisingly low and have stagnated since the late 1980s. Despite rising growth, fertility decline, and rising wage and education levels, married women's labor force participation hovered around 18 percent. Analysis of

  2. Evaluation of two streamlined life cycle assessment methods

    International Nuclear Information System (INIS)

    Hochschomer, Elisabeth; Finnveden, Goeran; Johansson, Jessica

    2002-02-01

    Two different methods for streamlined life cycle assessment (LCA) are described: the MECO-method and SLCA. Both methods are tested on an already made case-study on cars fuelled with petrol or ethanol, and electric cars with electricity produced from hydro power or coal. The report also contains some background information on LCA and streamlined LCA, and a deschption of the case study used. The evaluation of the MECO and SLCA-methods are based on a comparison of the results from the case study as well as practical aspects. One conclusion is that the SLCA-method has some limitations. Among the limitations are that the whole life-cycle is not covered, it requires quite a lot of information and there is room for arbitrariness. It is not very flexible instead it difficult to develop further. We are therefore not recommending the SLCA-method. The MECO-method does in comparison show several attractive features. It is also interesting to note that the MECO-method produces information that is complementary compared to a more traditional quantitative LCA. We suggest that the MECO method needs some further development and adjustment to Swedish conditions

  3. Effect of the Aligned Flow Obstacles on Downward-Facing CHF in an Inclined Rectangular Channel

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Ui ju; Son, Hong Hyun; Seo, Gwang Hyeok; Jeun, Gyoo Dong; Kim, Sung Joong [Hanyang, Seoul (Korea, Republic of)

    2016-05-15

    The cooling channel consists of the inclined (10 .deg. ) portion of the downward facing heating channel and vertical portion of the heating channel. Features unique to flow boiling with the downward-facing heater surface in the inclined cooling channel where the studs are installed have drawn a considerable attention. That's because prior studies on boiling crisis indicate the orientation of the heated wall can exert substantial influence on CHF. Especially, the concentration of the vapor near the downward facing heater surface makes this region susceptible to premature boiling crisis when compared to vertical or upward-facing heated wall. Also, the installed studs could cause a partial flow blockage, and distort the flow streamline. Due to the distortion, stagnation points may occur in the cooling channel, promoting the concentration of the vapor near the heated wall. Then, the locally degraded heat transfer around the points may result in the formation of vapor pocket. The primary objective of this study is to make available experimental data on the CHF values varying the shape of studs and to improve understanding of the mechanism of flow boiling crisis associated with the aligned flow obstructions by means of visual experimental study. This study presents experimental data for subcooled flow boiling of water at atmospheric pressure and low mass flux conditions. The major outcomes from this investigation can be summarized as follows: (1) The CHF value from bare test section is -320kW/m{sup 2} , significantly lower than the values from the existing correlations even considering the uncertainty in the experiments. (2) The CHF value is remarkably decreased as columnar structures are installed in the channel. It is confirmed that formation and extinction of local dryout occurs repeatedly just behind the first stud at heat flux of -160 kW/m{sup 2}.

  4. Vortex Generators in a Streamline-Traced, External-Compression Supersonic Inlet

    Science.gov (United States)

    Baydar, Ezgihan; Lu, Frank K.; Slater, John W.; Trefny, Charles J.

    2017-01-01

    Vortex generators within a streamline-traced, external-compression supersonic inlet for Mach 1.66 were investigated to determine their ability to increase total pressure recovery and reduce total pressure distortion. The vortex generators studied were rectangular vanes arranged in counter-rotating and co-rotating arrays. The vane geometric factors of interest included height, length, spacing, angle-of-incidence, and positions upstream and downstream of the inlet terminal shock. The flow through the inlet was simulated numerically through the solution of the steady-state, Reynolds-averaged Navier-Stokes equations on multi-block, structured grids using the Wind-US flow solver. The vanes were simulated using a vortex generator model. The inlet performance was characterized by the inlet total pressure recovery and the radial and circumferential total pressure distortion indices at the engine face. Design of experiments and statistical analysis methods were applied to quantify the effect of the geometric factors of the vanes and search for optimal vane arrays. Co-rotating vane arrays with negative angles-of-incidence positioned on the supersonic diffuser were effective in sweeping low-momentum flow from the top toward the sides of the subsonic diffuser. This distributed the low-momentum flow more evenly about the circumference of the subsonic diffuser and reduced distortion. Co-rotating vane arrays with negative angles-of-incidence or counter-rotating vane arrays positioned downstream of the terminal shock were effective in mixing higher-momentum flow with lower-momentum flow to increase recovery and decrease distortion. A strategy of combining a co-rotating vane array on the supersonic diffuser with a counter-rotating vane array on the subsonic diffuser was effective in increasing recovery and reducing distortion.

  5. Heat transfer in MHD unsteady stagnation point flow with variable wall temperature

    Digital Repository Service at National Institute of Oceanography (India)

    Soundalgekar, V.M.; Murty, T.V.R.; Takhar, H.S.

    stream_size 8739 stream_content_type text/plain stream_name Indian_J_Pure_Appl_Math_21_384.pdf.txt stream_source_info Indian_J_Pure_Appl_Math_21_384.pdf.txt Content-Encoding UTF-8 Content-Type text/plain; charset=UTF-8.... Soc. A224 (1954), 1-23. 2. S. I. Cheng and D. Elliott, Heat Transfer and Fluid Mech. IlIstitUfl?, S:anfoni University. Stanford (CA). 1956, p.p.221-38. 3. S. I. Cheng, Quart. appl. Math. 14 (1956-1957), 337-52. (\\ K. T. Yang, J. Appl. Mecll. (Tr. ASME...

  6. Streamlining of the Decontamination and Demolition Document Preparation Process

    International Nuclear Information System (INIS)

    Durand, Nick; Meincke, Carol; Peek, Georgianne

    1999-01-01

    During the past five years, the Sandia National Labo- ratories Decontamination, Decommissioning, Demolition, and Reuse (D3R) Program has evolved and become more focused and efficient. Historical approaches to project documentation, requirements, and drivers are discussed detailing key assumptions, oversight authority, and proj- ect approvals. Discussion of efforts to streamline the D3R project planning and preparation process include the in- corporation of the principles of graded approach, Total Quality Management, and the Observational Method (CH2MHILL April 1989).1 Process improvements were realized by clearly defining regulatory requirements for each phase of a project, establishing general guidance for the program and combining project-specific documents to eliminate redundant and unneeded information. Proc- ess improvements to cost, schedule, and quality are dis- cussed in detail for several projects

  7. The Zig-zag Instability of Streamlined Bodies

    Science.gov (United States)

    Guillet, Thibault; Coux, Martin; Quere, David; Clanet, Christophe

    2017-11-01

    When a floating bluff body, like a sphere, impacts water with a vertical velocity, its trajectory is straight and the depth of its dive increases with its initial velocity. Even though we observe the same phenomenon at low impact speed for axisymmetric streamlined bodies, the trajectory is found to deviate from the vertical when the velocity overcomes a critical value. This instability results from a competition between the destabilizing torque of the lift and the stabilizing torque of the Archimede's force. Balancing these torques yields a prediction on the critical velocity above which the instability appears. This theoretical value is found to depend on the position of the gravity center of the projectile and predicts with a full agreement the behaviour observed in our different experiments. Project funded by DGA.

  8. State Models to Incentivize and Streamline Small Hydropower Development

    Energy Technology Data Exchange (ETDEWEB)

    Curtis, Taylor [National Renewable Energy Lab. (NREL), Golden, CO (United States); Levine, Aaron [National Renewable Energy Lab. (NREL), Golden, CO (United States); Johnson, Kurt [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2017-10-31

    In 2016, the hydropower fleet in the United States produced more than 6 percent (approximately 265,829 gigawatt-hours [GWh]) of the total net electricity generation. The median-size hydroelectric facility in the United States is 1.6 MW and 75 percent of total facilities have a nameplate capacity of 10 MW or less. Moreover, the U.S. Department of Energy's Hydropower Vision study identified approximately 79 GW hydroelectric potential beyond what is already developed. Much of the potential identified is at low-impact new stream-reaches, existing conduits, and non-powered dams with a median project size of 10 MW or less. To optimize the potential and value of small hydropower development, state governments are crafting policies that provide financial assistance and expedite state and federal review processes for small hydroelectric projects. This report analyzes state-led initiatives and programs that incentivize and streamline small hydroelectric development.

  9. Streamlined bioreactor-based production of human cartilage tissues.

    Science.gov (United States)

    Tonnarelli, B; Santoro, R; Adelaide Asnaghi, M; Wendt, D

    2016-05-27

    Engineered tissue grafts have been manufactured using methods based predominantly on traditional labour-intensive manual benchtop techniques. These methods impart significant regulatory and economic challenges, hindering the successful translation of engineered tissue products to the clinic. Alternatively, bioreactor-based production systems have the potential to overcome such limitations. In this work, we present an innovative manufacturing approach to engineer cartilage tissue within a single bioreactor system, starting from freshly isolated human primary chondrocytes, through the generation of cartilaginous tissue grafts. The limited number of primary chondrocytes that can be isolated from a small clinically-sized cartilage biopsy could be seeded and extensively expanded directly within a 3D scaffold in our perfusion bioreactor (5.4 ± 0.9 doublings in 2 weeks), bypassing conventional 2D expansion in flasks. Chondrocytes expanded in 3D scaffolds better maintained a chondrogenic phenotype than chondrocytes expanded on plastic flasks (collagen type II mRNA, 18-fold; Sox-9, 11-fold). After this "3D expansion" phase, bioreactor culture conditions were changed to subsequently support chondrogenic differentiation for two weeks. Engineered tissues based on 3D-expanded chondrocytes were more cartilaginous than tissues generated from chondrocytes previously expanded in flasks. We then demonstrated that this streamlined bioreactor-based process could be adapted to effectively generate up-scaled cartilage grafts in a size with clinical relevance (50 mm diameter). Streamlined and robust tissue engineering processes, as the one described here, may be key for the future manufacturing of grafts for clinical applications, as they facilitate the establishment of compact and closed bioreactor-based production systems, with minimal automation requirements, lower operating costs, and increased compliance to regulatory guidelines.

  10. Streamlining cardiovascular clinical trials to improve efficiency and generalisability.

    Science.gov (United States)

    Zannad, Faiez; Pfeffer, Marc A; Bhatt, Deepak L; Bonds, Denise E; Borer, Jeffrey S; Calvo-Rojas, Gonzalo; Fiore, Louis; Lund, Lars H; Madigan, David; Maggioni, Aldo Pietro; Meyers, Catherine M; Rosenberg, Yves; Simon, Tabassome; Stough, Wendy Gattis; Zalewski, Andrew; Zariffa, Nevine; Temple, Robert

    2017-08-01

    Controlled trials provide the most valid determination of the efficacy and safety of an intervention, but large cardiovascular clinical trials have become extremely costly and complex, making it difficult to study many important clinical questions. A critical question, and the main objective of this review, is how trials might be simplified while maintaining randomisation to preserve scientific integrity and unbiased efficacy assessments. Experience with alternative approaches is accumulating, specifically with registry-based randomised controlled trials that make use of data already collected. This approach addresses bias concerns while still capitalising on the benefits and efficiencies of a registry. Several completed or ongoing trials illustrate the feasibility of using registry-based controlled trials to answer important questions relevant to daily clinical practice. Randomised trials within healthcare organisation databases may also represent streamlined solutions for some types of investigations, although data quality (endpoint assessment) is likely to be a greater concern in those settings. These approaches are not without challenges, and issues pertaining to informed consent, blinding, data quality and regulatory standards remain to be fully explored. Collaboration among stakeholders is necessary to achieve standards for data management and analysis, to validate large data sources for use in randomised trials, and to re-evaluate ethical standards to encourage research while also ensuring that patients are protected. The rapidly evolving efforts to streamline cardiovascular clinical trials have the potential to lead to major advances in promoting better care and outcomes for patients with cardiovascular disease. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  11. Supply chain cost improvement opportunities through streamlining cross-border operations

    Directory of Open Access Journals (Sweden)

    Jan Hendrik Havenga

    2013-09-01

    Full Text Available The Cross-Border Road Transport Agency (CBRTA in South Africa aims to encourage and facilitate trade between South Africa and its neighbouring countries. The CBRTA sponsored a study by Stellenbosch University (SU to determine the logistics cost impact of cross-border delays between South Africa and its major neighbouring trading partners, and prioritise opportunities for improvement. SU is the proprietor of both a comprehensive freight demand model and a logistics cost model for South Africa, which enable extractions and extensions of freight flows and related costs for specific purposes. Through the application of these models, the following information is identified and presented in this paper: South Africa’s most important border posts (based on traffic flows; a product profile for imports and exports through these border posts; the modal split (road and rail; the annual logistics costs incurred on the corridors feeding the border posts, as well as the additional costs incurred due to border delays. The research has proved that the streamlining of border-post operations that take a total supply chain view (i.e. of both border operations and those that could be moved from the border is beneficial.

  12. Using absolute x-ray spectral measurements to infer stagnation conditions in ICF implosions

    Science.gov (United States)

    Patel, Pravesh; Benedetti, L. R.; Cerjan, C.; Clark, D. S.; Hurricane, O. A.; Izumi, N.; Jarrott, L. C.; Khan, S.; Kritcher, A. L.; Ma, T.; Macphee, A. G.; Landen, O.; Spears, B. K.; Springer, P. T.

    2016-10-01

    Measurements of the continuum x-ray spectrum emitted from the hot-spot of an ICF implosion can be used to infer a number thermodynamic properties at stagnation including temperature, pressure, and hot-spot mix. In deuterium-tritium (DT) layered implosion experiments on the National Ignition Facility (NIF) we field a number of x-ray diagnostics that provide spatial, temporal, and spectrally-resolved measurements of the radiated x-ray emission. We report on analysis of these measurements using a 1-D hot-spot model to infer thermodynamic properties at stagnation. We compare these to similar properties that can be derived from DT fusion neutron measurements. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  13. Modeling of Aerobrake Ballute Stagnation Point Temperature and Heat Transfer to Inflation Gas

    Science.gov (United States)

    Bahrami, Parviz A.

    2012-01-01

    A trailing Ballute drag device concept for spacecraft aerocapture is considered. A thermal model for calculation of the Ballute membrane temperature and the inflation gas temperature is developed. An algorithm capturing the most salient features of the concept is implemented. In conjunction with the thermal model, trajectory calculations for two candidate missions, Titan Explorer and Neptune Orbiter missions, are used to estimate the stagnation point temperature and the inflation gas temperature. Radiation from both sides of the membrane at the stagnation point and conduction to the inflating gas is included. The results showed that the radiation from the membrane and to a much lesser extent conduction to the inflating gas, are likely to be the controlling heat transfer mechanisms and that the increase in gas temperature due to aerodynamic heating is of secondary importance.

  14. Current redistribution and generation of kinetic energy in the stagnated Z pinch.

    Science.gov (United States)

    Ivanov, V V; Anderson, A A; Papp, D; Astanovitskiy, A L; Talbot, B R; Chittenden, J P; Niasse, N

    2013-07-01

    The structure of magnetic fields was investigated in stagnated wire-array Z pinches using a Faraday rotation diagnostic at the wavelength of 266 nm. The distribution of current in the pinch and trailing material was reconstructed. A significant part of current can switch from the main pinch to the trailing plasma preheated by x-ray radiation of the pinch. Secondary implosions of trailing plasma generate kinetic energy and provide enhanced heating and radiation of plasma at stagnation. Hot spots in wire-array Z pinches also provide enhanced radiation of the Z pinch. A collapse of a single hot spot radiates 1%-3% of x-ray energy of the Z pinch with a total contribution of hot spots of 10%-30%.

  15. Responses of three-dimensional flow to variations in the angle of incident wind and profile form of dunes: Greenwich Dunes, Prince Edward Island, Canada

    Science.gov (United States)

    Walker, Ian J.; Hesp, Patrick A.; Davidson-Arnott, Robin G. D.; Bauer, Bernard O.; Namikas, Steven L.; Ollerhead, Jeff

    2009-04-01

    This study reports the responses of three-dimensional near-surface airflow over a vegetated foredune to variations in the conditions of incident flow during an 8-h experiment. Two parallel measurement transects were established on morphologically different dune profiles: i) a taller, concave-convex West foredune transect with 0.5-m high, densely vegetated (45%), seaward incipient foredune, and ii) a shorter, concave-straight East foredune transect with lower, sparsely vegetated (14%) seaward incipient foredune. Five stations on each transect from the incipient dune to the crest were equipped with ultrasonic anemometers at 0.6 and 1.65 m height and logged at 1 Hz. Incident conditions were recorded from a 4-m tower over a flat beach. Winds increased from 6 m s - 1 to > 20 m s - 1 and were generally obliquely onshore (ENE, 73°). Three sub-events and the population of 10-minute averages of key properties of flow ( U, W, S, CV U) from all sample locations on the East transect ( n = 235) are examined to identify location- and profile-specific responses over 52° of the incident direction of flow (from 11 to 63° onshore). Topographic steering and forcing cause major deviations in the properties and vectors of near-surface flow from the regional wind. Topographic forcing on the concave-straight dune profile increases wind speed and steadiness toward the crest, with speed-up values to 65% in the backshore. Wind speed and steadiness of flow are least responsive to changes in incident angle in the backshore because of stagnation of flow and are most responsive at the lower stoss under pronounced streamline compression. On the steeper concave-convex profile, speed and steadiness decrease toward the crest because of stagnation of flow at the toe and flow expansion at the slope inflection point on the lower stoss. Net downward vertical velocity occurs over both profiles, increases toward the crest, and reflects enhanced turbulent momentum conveyance toward the surface. All of

  16. New optical method for heat flux measurements in stagnation point laminar methane/air flames and hydrogen/methane/air flames using thermographic phosphors

    Energy Technology Data Exchange (ETDEWEB)

    Elmnefi, Mohamed Salem

    2010-11-24

    In the present study, a new optical method was implemented to study the heat transfer from flat stagnation point flames which can be regarded as one-dimensional in the central part. Premixed methane-air flames and hydrogen-methane-air flames were investigated. The effects of burner-to-plate distance and the fresh gas mixture velocity on heat transfer were examined. Experiments were performed using light induced phosphorescence from thermographic phosphors to study the wall temperatures and heat fluxes of nearly one-dimensional flat premixed flames impinging upward normally on a horizontal water cooled circular flat plate. The investigated flames were stoichiometric, lean and rich laminar methane/air flames with different equivalence ratios of {phi} =1, {phi} = 0.75 and {phi} = 1.25 and stoichiometric laminar hydrogen/methane/air flames. Mixtures of air with 10, 25, 50 and 75 % hydrogen in methane (CH{sub 4}) as well as a pure hydrogen flames at ambient pressure were investigated. The central part of this plate was an alumina ceramic plate coated from both sides with chromium doped alumina (ruby) and excited with a Nd:YAG laser or a green light emitting diode (LED) array to measure the wall temperature from both sides and thus the heat flux rate from the flame. The outlet velocity of the gases was varied from 0.1 m/s to 1.2 m/s. The burner to plate distance ranged from 0.5 to 2 times the burner exit diameter (d = 30 mm).The accuracy of the method was evaluated. The measured heat flux indicate the change of the flame stabilization mechanism from a burner stabilized to a stagnation plate stabilized flame. The results were compared to modeling results of a one dimensional stagnation point flow, with a detailed reaction mechanism. In order to prove the model, also measured gas phase temperatures by OH LIF for a stoichiometric stagnation point flame were discussed. It turns out that the flame stabilization mechanism and with it the heat fluxes change from low to high

  17. Bulk damping of sound in superfluid 3He--4He under stagnation of the normal component

    International Nuclear Information System (INIS)

    Karchava, T.A.; Sanikidze, D.G.; Chkhaidze, N.D.

    1983-01-01

    The propagation of waves in superfluid 3 He-- 4 He solutions is considered under partial stagnation of the normal component. The wave processes in capillaries are presented as a superposition of the first sound, second sound, and viscous and diffusion waves. The damping coefficients are calculated for the modified first sound and for the thermal wave in superfluid 3 He-- 4 He solutions and related to the viscosity, thermal conductivity, diffusion, barodiffusion, and thermodiffusion coefficients

  18. Study of atmospheric stagnation, recirculation, and ventilation potential at Narora Atomic Power Station site

    International Nuclear Information System (INIS)

    Kumar, Deepak; Kumar, Avinash; Kumar, Vimal; Rao, K.S.; Kumar, Jaivender; Ravi, P.M.

    2011-01-01

    Atmosphere is an important pathway to be considered in assessment of the environmental impact of radioactivity releases from nuclear facilities. Estimation of concentration of released effluents in air and possible ground contamination needs an understanding of relevant atmospheric dispersion. This article describes the meteorological characteristics of Narora Atomic Power Station (NAPS) site by using the integral parameters developed by Allwine and Whiteman. Meteorological data measured during the period 2006-2010 were analyzed. The integral quantities related to the occurrence of stagnation, recirculation, and ventilation characteristics were studied for NAPS site to assess the dilution potential of the atmosphere. Wind run and recirculation factors were calculated for a 24-h transport time using 5 years of hourly surface measurements of wind speed and direction. The occurrence of stagnation, recirculation, and ventilation characteristics during 2006-2010 at NAPS site is observed to be 33.8% of the time, 19.5% of the time, and 34.7% of the time, respectively. The presence of strong winds with predominant wind direction NW and WNW during winter and summer seasons leads to higher ventilation (48.1% and 44.3%) and recirculation (32.6% of the summer season). The presence of light winds and more dispersed winds during prewinter season with predominant wind directions W and WNW results in more stagnation (59.7% of the prewinter season). Thus, this study will serve as an essential meteorological tool to understand the transport mechanism of atmospheric radioactive effluent releases from any nuclear industry. (author)

  19. Efficient solution to the stagnation problem of the particle swarm optimization algorithm for phase diversity.

    Science.gov (United States)

    Qi, Xin; Ju, Guohao; Xu, Shuyan

    2018-04-10

    The phase diversity (PD) technique needs optimization algorithms to minimize the error metric and find the global minimum. Particle swarm optimization (PSO) is very suitable for PD due to its simple structure, fast convergence, and global searching ability. However, the traditional PSO algorithm for PD still suffers from the stagnation problem (premature convergence), which can result in a wrong solution. In this paper, the stagnation problem of the traditional PSO algorithm for PD is illustrated first. Then, an explicit strategy is proposed to solve this problem, based on an in-depth understanding of the inherent optimization mechanism of the PSO algorithm. Specifically, a criterion is proposed to detect premature convergence; then a redistributing mechanism is proposed to prevent premature convergence. To improve the efficiency of this redistributing mechanism, randomized Halton sequences are further introduced to ensure the uniform distribution and randomness of the redistributed particles in the search space. Simulation results show that this strategy can effectively solve the stagnation problem of the PSO algorithm for PD, especially for large-scale and high-dimension wavefront sensing and noisy conditions. This work is further verified by an experiment. This work can improve the robustness and performance of PD wavefront sensing.

  20. Large scale flow in the dayside magnetosheath

    International Nuclear Information System (INIS)

    Crooker, N.U.; Siscoe, G.L.; Eastman, T.E.; Frank, L.A.; Zwickl, R.D.

    1984-01-01

    The degree of control over plasma flow direction exerted by the compressed magnetic field in the dayside magnetosheath is examined by comparing ISEE 1 LEPEDEA data with hydrodynamic and magnetohydrodynamic predictions. Measured flow directions projected toward the subsolar region pass within approx.1 R/sub E/ of the aberrated theoretical hydrodynamic stagnation point in 11 of 20 cases analyzed. The remaining nine cases pass within approx.2-3 R/sub E/ of the stagnation point. One case with large deflection has been studied in detail with large-time-resolution plasma and magnetic field data both from ISEE 1 and from ISEE 3, in the role of a solar wind monitor. The deflected flow is persitent over a period of 1 1/2 hours, and its direction is consistent with a stagnation point displacement resulting from increased, asymmetric magnetic field pressure contributions during periods of low Alfven Mach number, as predicted by Russell et al. Of the other eight cases with large deflections, four are associated with flux transfer events identified independently by Berchem and Russell. The observed deflections in these cases are consistent with either the subsolar merging line or the antiparallel merging hypothesis, but not exclusively with one or the other. The results relating to the formation of a stagnation line rather than a stagnation point are inconclusive

  1. Three dimensional numerical investigation of flow mixing in curved tubes and mass transfer in T-channel junction

    International Nuclear Information System (INIS)

    Pandey, Pradeep; Nayak, A.K.; Vijayan, P.K.

    2014-01-01

    Three dimensional flow patterns appearing in geometries such as curved pipes and T-channel junctions have important applications and are attractive for research. Unlike the flow in a straight tube, fluid motion in a curved tube is not parallel to the axis of bend, owing to the presence of centrifugal effects. It is characterized by a secondary flow in a cross-sectional plane normal to the main flow. Consequently, secondary flow separation near the inner wall is observed in the developing region. The strength of the secondary flow is greatly influenced by the curvature ratio and in turn, a non-dimensional parameter called the Dean Number. Secondary flow increases flow resistance, resulting in a larger pressure drop along the bend. The location of the maximum axial velocity gets shifted towards the outer wall. Flow in a T-channel junction is also a configuration of great significance. The simulations of the present work show that flow at low Reynolds numbers (Re ≤ 115) is steady and symmetric. For low Reynolds numbers, flow in the downstream channel remains highly segregated about the centerline. The appearance of vortices in the T-channel junction does little to redistribute concentration when flow remains symmetric. With increasing Reynolds number, transition takes place towards asymmetric flow. The incoming flow field gets redistributed at the center-plane and the dividing streamline becomes increasingly distorted. The flow field is characterized by thin elongated fluid interfaces across which momentum diffusion takes place. Flow at higher Reynolds numbers (Re ≥ 250) becomes unsteady in which unstable stagnation stream traces move periodically leftward and rightward at top and bottom walls. Trajectories of mass-less particles show greater dwelling in the junction as compared to those of finite mass particle. The numerical simulation is carried out in the present work using ANUPRAVAHA, a general purpose CFD solver developed at IIT Kanpur in collaboration with

  2. The Role of Rumination and Stressful Life Events in the Relationship between the Qi Stagnation Constitution and Depression in Women: A Moderated Mediation Model

    Science.gov (United States)

    Liu, Qiaosheng

    2017-01-01

    The qi stagnation constitution is associated with depression in traditional Chinese medicine. It is unclear how rumination and stressful life events affect the relationship between the qi stagnation constitution and depression. The Qi Stagnation Constitution Scale, Ruminative Response Scale, Center for Epidemiologic Studies Depression Scale, and Adolescent Self-Rating Life Events Checklist were used to assess this association in 1200 female college students. The results revealed that the qi stagnation constitution was positively associated with depression. Furthermore, rumination was a partial mediator of the relationship between the qi stagnation constitution and depression. In addition, stressful life events moderated the direct effect and mediating effect of the qi stagnation constitution on depression. These findings indicate that rumination and stressful life events may affect the relationship between the qi stagnation constitution and depression in women. PMID:28757889

  3. The Role of Rumination and Stressful Life Events in the Relationship between the Qi Stagnation Constitution and Depression in Women: A Moderated Mediation Model

    Directory of Open Access Journals (Sweden)

    Mingfan Liu

    2017-01-01

    Full Text Available The qi stagnation constitution is associated with depression in traditional Chinese medicine. It is unclear how rumination and stressful life events affect the relationship between the qi stagnation constitution and depression. The Qi Stagnation Constitution Scale, Ruminative Response Scale, Center for Epidemiologic Studies Depression Scale, and Adolescent Self-Rating Life Events Checklist were used to assess this association in 1200 female college students. The results revealed that the qi stagnation constitution was positively associated with depression. Furthermore, rumination was a partial mediator of the relationship between the qi stagnation constitution and depression. In addition, stressful life events moderated the direct effect and mediating effect of the qi stagnation constitution on depression. These findings indicate that rumination and stressful life events may affect the relationship between the qi stagnation constitution and depression in women.

  4. Streamlining Collaboration for the Gravitational-wave Astronomy Community

    Science.gov (United States)

    Koranda, S.

    2016-12-01

    In the morning hours of September 14, 2015 the LaserInterferometer Gravitational-wave Observatory (LIGO) directlydetected gravitational waves from inspiraling and coalescingblack holes, confirming a major prediction of AlbertEinstein's general theory of relativity and beginning the eraof gravitational-wave astronomy. With the LIGO detectors in the United States, the Virgo andGEO detectors in Europe, and the KAGRA detector in Japan thegravitational-wave astrononmy community is opening a newwindow on our Universe. Realizing the full science potentialof LIGO and the other interferometers requires globalcollaboration not only within the gravitational-wave astronomycommunity but also with the astronomers and astrophysicists acrossmultipe disciplines working to realize and leverage the powerof multi-messenger astronomy. Enabling thousands of researchers from around the world andacross multiple projects to efficiently collaborate, share,and analyze data and provide streamlined access to services,computing, and tools requires new and scalable approaches toidentity and access management (IAM). We will discuss LIGO'sIAM journey that began in 2007 and how today LIGO leveragesinternal identity federations like InCommon and eduGAIN toprovide scalable and managed access for the gravitational-waveastronomy community. We will discuss the steps both largeand small research organizations and projects take as theirIAM infrastructure matures from ad-hoc silos of independent services to fully integrated and federated services thatstreamline collaboration so that scientists can focus onresearch and not managing passwords.

  5. An integrated billing application to streamline clinician workflow.

    Science.gov (United States)

    Vawdrey, David K; Walsh, Colin; Stetson, Peter D

    2014-01-01

    Between 2008 and 2010, our academic medical center transitioned to electronic provider documentation using a commercial electronic health record system. For attending physicians, one of the most frustrating aspects of this experience was the system's failure to support their existing electronic billing workflow. Because of poor system integration, it was difficult to verify the supporting documentation for each bill and impractical to track whether billable notes had corresponding charges. We developed and deployed in 2011 an integrated billing application called "iCharge" that streamlines clinicians' documentation and billing workflow, and simultaneously populates the inpatient problem list using billing diagnosis codes. Each month, over 550 physicians use iCharge to submit approximately 23,000 professional service charges for over 4,200 patients. On average, about 2.5 new problems are added to each patient's problem list. This paper describes the challenges and benefits of workflow integration across disparate applications and presents an example of innovative software development within a commercial EHR framework.

  6. Lessons learned in streamlining the preparation of SNM standard solutions

    International Nuclear Information System (INIS)

    Clark, J.P.; Johnson, S.R.

    1986-01-01

    Improved safeguard measurements have produced a demand for greater quantities of reliable SNM solution standards. At the Savannah River Plant (SRP), the demand for these standards has been met by several innovations to improve the productivity and reliability of standards preparations. With the use of computer controlled balance, large batches of SNM stock solutions are prepared on a gravimetric basis. Accurately dispensed quantities of the stock solution are weighed and stored in bottles. When needed, they are quantitatively transferred to tared containers, matrix adjusted to target concentrations, weighed, and measured for density at 25 0 C. Concentrations of SNM are calculated both gravimetrically and volumetrically. Calculated values are confirmed analytically before the standards are used in measurement control program (MCP) activities. The lessons learned include: MCP goals include error identification and management. Strategy modifications are required to improve error management. Administrative controls can minimize certain types of errors. Automation can eliminate redundancy and streamline preparations. Prudence and simplicity enhance automation success. The effort expended to increase productivity has increased the reliability of standards and provided better documentation for quality assurance

  7. VISMASHUP: streamlining the creation of custom visualization applications

    Energy Technology Data Exchange (ETDEWEB)

    Ahrens, James P [Los Alamos National Laboratory; Santos, Emanuele [UNIV OF UTAH; Lins, Lauro [UNIV OF UTAH; Freire, Juliana [UNIV OF UTAH; Silva, Cl' audio T [UNIV OF UTAH

    2010-01-01

    Visualization is essential for understanding the increasing volumes of digital data. However, the process required to create insightful visualizations is involved and time consuming. Although several visualization tools are available, including tools with sophisticated visual interfaces, they are out of reach for users who have little or no knowledge of visualization techniques and/or who do not have programming expertise. In this paper, we propose VISMASHUP, a new framework for streamlining the creation of customized visualization applications. Because these applications can be customized for very specific tasks, they can hide much of the complexity in a visualization specification and make it easier for users to explore visualizations by manipulating a small set of parameters. We describe the framework and how it supports the various tasks a designer needs to carry out to develop an application, from mining and exploring a set of visualization specifications (pipelines), to the creation of simplified views of the pipelines, and the automatic generation of the application and its interface. We also describe the implementation of the system and demonstrate its use in two real application scenarios.

  8. Microdiversification in genome-streamlined ubiquitous freshwater Actinobacteria.

    Science.gov (United States)

    Neuenschwander, Stefan M; Ghai, Rohit; Pernthaler, Jakob; Salcher, Michaela M

    2018-01-01

    Actinobacteria of the acI lineage are the most abundant microbes in freshwater systems, but there are so far no pure living cultures of these organisms, possibly because of metabolic dependencies on other microbes. This, in turn, has hampered an in-depth assessment of the genomic basis for their success in the environment. Here we present genomes from 16 axenic cultures of acI Actinobacteria. The isolates were not only of minute cell size, but also among the most streamlined free-living microbes, with extremely small genome sizes (1.2-1.4 Mbp) and low genomic GC content. Genome reduction in these bacteria might have led to auxotrophy for various vitamins, amino acids and reduced sulphur sources, thus creating dependencies to co-occurring organisms (the 'Black Queen' hypothesis). Genome analyses, moreover, revealed a surprising degree of inter- and intraspecific diversity in metabolic pathways, especially of carbohydrate transport and metabolism, and mainly encoded in genomic islands. The striking genotype microdiversification of acI Actinobacteria might explain their global success in highly dynamic freshwater environments with complex seasonal patterns of allochthonous and autochthonous carbon sources. We propose a new order within Actinobacteria ('Candidatus Nanopelagicales') with two new genera ('Candidatus Nanopelagicus' and 'Candidatus Planktophila') and nine new species.

  9. A streamlined artificial variable free version of simplex method.

    Directory of Open Access Journals (Sweden)

    Syed Inayatullah

    Full Text Available This paper proposes a streamlined form of simplex method which provides some great benefits over traditional simplex method. For instance, it does not need any kind of artificial variables or artificial constraints; it could start with any feasible or infeasible basis of an LP. This method follows the same pivoting sequence as of simplex phase 1 without showing any explicit description of artificial variables which also makes it space efficient. Later in this paper, a dual version of the new method has also been presented which provides a way to easily implement the phase 1 of traditional dual simplex method. For a problem having an initial basis which is both primal and dual infeasible, our methods provide full freedom to the user, that whether to start with primal artificial free version or dual artificial free version without making any reformulation to the LP structure. Last but not the least, it provides a teaching aid for the teachers who want to teach feasibility achievement as a separate topic before teaching optimality achievement.

  10. A streamlined artificial variable free version of simplex method.

    Science.gov (United States)

    Inayatullah, Syed; Touheed, Nasir; Imtiaz, Muhammad

    2015-01-01

    This paper proposes a streamlined form of simplex method which provides some great benefits over traditional simplex method. For instance, it does not need any kind of artificial variables or artificial constraints; it could start with any feasible or infeasible basis of an LP. This method follows the same pivoting sequence as of simplex phase 1 without showing any explicit description of artificial variables which also makes it space efficient. Later in this paper, a dual version of the new method has also been presented which provides a way to easily implement the phase 1 of traditional dual simplex method. For a problem having an initial basis which is both primal and dual infeasible, our methods provide full freedom to the user, that whether to start with primal artificial free version or dual artificial free version without making any reformulation to the LP structure. Last but not the least, it provides a teaching aid for the teachers who want to teach feasibility achievement as a separate topic before teaching optimality achievement.

  11. Experimental analysis of flow of ductile cast iron in stream lined gating systems

    DEFF Research Database (Denmark)

    Skov-Hansen, Søren Peter; Tiedje, Niels Skat

    2008-01-01

    Streamlined gating systems have been developed for production of high integrity ductile cast iron parts. Flow of ductile cast iron in streamlined gating systems was studied in glass fronted sand moulds where flow in the gating system and casting was recorded by a digital video camera. These results...... show how the quality of pouring, design of ingates, design of bends and flow over cores influence melt flow and act to determine the quality of the castings....

  12. Streamlined, Inexpensive 3D Printing of the Brain and Skull.

    Science.gov (United States)

    Naftulin, Jason S; Kimchi, Eyal Y; Cash, Sydney S

    2015-01-01

    Neuroimaging technologies such as Magnetic Resonance Imaging (MRI) and Computed Tomography (CT) collect three-dimensional data (3D) that is typically viewed on two-dimensional (2D) screens. Actual 3D models, however, allow interaction with real objects such as implantable electrode grids, potentially improving patient specific neurosurgical planning and personalized clinical education. Desktop 3D printers can now produce relatively inexpensive, good quality prints. We describe our process for reliably generating life-sized 3D brain prints from MRIs and 3D skull prints from CTs. We have integrated a standardized, primarily open-source process for 3D printing brains and skulls. We describe how to convert clinical neuroimaging Digital Imaging and Communications in Medicine (DICOM) images to stereolithography (STL) files, a common 3D object file format that can be sent to 3D printing services. We additionally share how to convert these STL files to machine instruction gcode files, for reliable in-house printing on desktop, open-source 3D printers. We have successfully printed over 19 patient brain hemispheres from 7 patients on two different open-source desktop 3D printers. Each brain hemisphere costs approximately $3-4 in consumable plastic filament as described, and the total process takes 14-17 hours, almost all of which is unsupervised (preprocessing = 4-6 hr; printing = 9-11 hr, post-processing = Printing a matching portion of a skull costs $1-5 in consumable plastic filament and takes less than 14 hr, in total. We have developed a streamlined, cost-effective process for 3D printing brain and skull models. We surveyed healthcare providers and patients who confirmed that rapid-prototype patient specific 3D models may help interdisciplinary surgical planning and patient education. The methods we describe can be applied for other clinical, research, and educational purposes.

  13. Streamlined, Inexpensive 3D Printing of the Brain and Skull.

    Directory of Open Access Journals (Sweden)

    Jason S Naftulin

    Full Text Available Neuroimaging technologies such as Magnetic Resonance Imaging (MRI and Computed Tomography (CT collect three-dimensional data (3D that is typically viewed on two-dimensional (2D screens. Actual 3D models, however, allow interaction with real objects such as implantable electrode grids, potentially improving patient specific neurosurgical planning and personalized clinical education. Desktop 3D printers can now produce relatively inexpensive, good quality prints. We describe our process for reliably generating life-sized 3D brain prints from MRIs and 3D skull prints from CTs. We have integrated a standardized, primarily open-source process for 3D printing brains and skulls. We describe how to convert clinical neuroimaging Digital Imaging and Communications in Medicine (DICOM images to stereolithography (STL files, a common 3D object file format that can be sent to 3D printing services. We additionally share how to convert these STL files to machine instruction gcode files, for reliable in-house printing on desktop, open-source 3D printers. We have successfully printed over 19 patient brain hemispheres from 7 patients on two different open-source desktop 3D printers. Each brain hemisphere costs approximately $3-4 in consumable plastic filament as described, and the total process takes 14-17 hours, almost all of which is unsupervised (preprocessing = 4-6 hr; printing = 9-11 hr, post-processing = <30 min. Printing a matching portion of a skull costs $1-5 in consumable plastic filament and takes less than 14 hr, in total. We have developed a streamlined, cost-effective process for 3D printing brain and skull models. We surveyed healthcare providers and patients who confirmed that rapid-prototype patient specific 3D models may help interdisciplinary surgical planning and patient education. The methods we describe can be applied for other clinical, research, and educational purposes.

  14. Streamlined, Inexpensive 3D Printing of the Brain and Skull

    Science.gov (United States)

    Cash, Sydney S.

    2015-01-01

    Neuroimaging technologies such as Magnetic Resonance Imaging (MRI) and Computed Tomography (CT) collect three-dimensional data (3D) that is typically viewed on two-dimensional (2D) screens. Actual 3D models, however, allow interaction with real objects such as implantable electrode grids, potentially improving patient specific neurosurgical planning and personalized clinical education. Desktop 3D printers can now produce relatively inexpensive, good quality prints. We describe our process for reliably generating life-sized 3D brain prints from MRIs and 3D skull prints from CTs. We have integrated a standardized, primarily open-source process for 3D printing brains and skulls. We describe how to convert clinical neuroimaging Digital Imaging and Communications in Medicine (DICOM) images to stereolithography (STL) files, a common 3D object file format that can be sent to 3D printing services. We additionally share how to convert these STL files to machine instruction gcode files, for reliable in-house printing on desktop, open-source 3D printers. We have successfully printed over 19 patient brain hemispheres from 7 patients on two different open-source desktop 3D printers. Each brain hemisphere costs approximately $3–4 in consumable plastic filament as described, and the total process takes 14–17 hours, almost all of which is unsupervised (preprocessing = 4–6 hr; printing = 9–11 hr, post-processing = Printing a matching portion of a skull costs $1–5 in consumable plastic filament and takes less than 14 hr, in total. We have developed a streamlined, cost-effective process for 3D printing brain and skull models. We surveyed healthcare providers and patients who confirmed that rapid-prototype patient specific 3D models may help interdisciplinary surgical planning and patient education. The methods we describe can be applied for other clinical, research, and educational purposes. PMID:26295459

  15. Managing Written Directives: A Software Solution to Streamline Workflow.

    Science.gov (United States)

    Wagner, Robert H; Savir-Baruch, Bital; Gabriel, Medhat S; Halama, James R; Bova, Davide

    2017-06-01

    A written directive is required by the U.S. Nuclear Regulatory Commission for any use of 131 I above 1.11 MBq (30 μCi) and for patients receiving radiopharmaceutical therapy. This requirement has also been adopted and must be enforced by the agreement states. As the introduction of new radiopharmaceuticals increases therapeutic options in nuclear medicine, time spent on regulatory paperwork also increases. The pressure of managing these time-consuming regulatory requirements may heighten the potential for inaccurate or incomplete directive data and subsequent regulatory violations. To improve on the paper-trail method of directive management, we created a software tool using a Health Insurance Portability and Accountability Act (HIPAA)-compliant database. This software allows for secure data-sharing among physicians, technologists, and managers while saving time, reducing errors, and eliminating the possibility of loss and duplication. Methods: The software tool was developed using Visual Basic, which is part of the Visual Studio development environment for the Windows platform. Patient data are deposited in an Access database on a local HIPAA-compliant secure server or hard disk. Once a working version had been developed, it was installed at our institution and used to manage directives. Updates and modifications of the software were released regularly until no more significant problems were found with its operation. Results: The software has been used at our institution for over 2 y and has reliably kept track of all directives. All physicians and technologists use the software daily and find it superior to paper directives. They can retrieve active directives at any stage of completion, as well as completed directives. Conclusion: We have developed a software solution for the management of written directives that streamlines and structures the departmental workflow. This solution saves time, centralizes the information for all staff to share, and decreases

  16. The influence of the stagnation zone on the fluid dynamics at the nozzle exit of a confined and submerged impinging jet

    Science.gov (United States)

    Jeffers, Nicholas; Stafford, Jason; Conway, Ciaran; Punch, Jeff; Walsh, Edmond

    2016-02-01

    Low profile impinging jets provide a means to achieve high heat transfer coefficients while occupying a small quantity of space. Consequently, they are found in many engineering applications such as electronics cooling, annealing of metals, food processing, and others. This paper investigates the influence of the stagnation zone fluid dynamics on the nozzle exit flow condition of a low profile, submerged, and confined impinging water jet. The jet was geometrically constrained to a round, 16-mm diameter, square-edged nozzle at a jet exit to target surface spacing ( H/ D) that varied between 0.25 choice of inlet boundary conditions in numerical models, and it was found that it is necessary to model a jet tube length {{ L}{/}{ D}} > 0.5—where D is the inner diameter of the jet—in order to minimise modelling uncertainty.

  17. Swedish district heating—A system in stagnation: Current and future trends in the district heating sector

    International Nuclear Information System (INIS)

    Magnusson, Dick

    2012-01-01

    This paper argues that Sweden’s old and established district heating sector is heading into a stagnation phase. The aim is to analyse the factors influencing this development as well as the strategies used by involved parties to prevent stagnation. Using large technical system theory, I analyse internal and external factors potentially causing stagnation. The most obvious external factors are: an increase in the number of energy-efficient buildings, in response to stricter energy policies, which reduces the future potential for district heating in new and existing buildings; climate change; competition from other heating systems; and market saturation in the key sector, multi-dwelling buildings. The main internal factor is changed business strategies following electricity market deregulation, when energy companies were supposed to be run on businesslike terms. I also argue that stagnation can be defined as occurring when the key measure feature of a system, in this case, heat load is starting to stagnate or decline, even though the trend is positive in other areas. The strategies for avoiding stagnation are various forms of broadening scope, primarily by focusing more on electricity production by building combined heat and power plants, or using the alternative value of the technical system for new applications. - Highlights: ► The Swedish district heating sector is heading into a stage of stagnation. ► The main reasons are: climate change, competition and energy efficient buildings. ► Strategies to change trend: broadening of scope by focusing on electricity in CHP plants. ► Contribution to Large Technical Systems—theory and the later phases of system development.

  18. Institutionel stagnation i hertugdømmet Slesvig 1840-1860

    DEFF Research Database (Denmark)

    Clausen, Thomas

    2017-01-01

    This article provides a study of the framework conditions for trade and industry in the Duchy of Schleswig in the middle of the 19th century. Grounded on theory of institutional economics the main argument of the paper is that Schleswig on a range of parameters suffered from stagnation...... in the development of the economy. The cause of this slowdown had to do with inertia in adaption of important institutional arrangement to the increasing complexity of trade and business. The study concludes that the Duchy, despite a seemingly favorable starting point, lost ground and that the institutional...

  19. Streamlining genomes: toward the generation of simplified and stabilized microbial systems

    NARCIS (Netherlands)

    Leprince, A.; Passel, van M.W.J.; Martins Dos Santos, V.A.P.

    2012-01-01

    At the junction between systems and synthetic biology, genome streamlining provides a solid foundation both for increased understanding of cellular circuitry, and for the tailoring of microbial chassis towards innovative biotechnological applications. Iterative genomic deletions (targeted and

  20. West Virginia Peer Exchange : Streamlining Highway Safety Improvement Program Project Delivery - An RSPCB Peer Exchange

    Science.gov (United States)

    2014-09-01

    The West Virginia Division of Highways (WV DOH) hosted a Peer Exchange to share information and experiences for streamlining Highway Safety Improvement Program (HSIP) project delivery. The event was held September 23 to 24, 2014 in Charleston, West V...

  1. 77 FR 50691 - Request for Information (RFI): Guidance on Data Streamlining and Reducing Undue Reporting Burden...

    Science.gov (United States)

    2012-08-22

    .... Attention: HIV Data Streamlining. FOR FURTHER INFORMATION CONTACT: Andrew D. Forsyth Ph.D. or Vera... of HIV/AIDS programs that vary in their specifications (e.g., numerators, denominators, time frames...

  2. West Virginia peer exchange : streamlining highway safety improvement program project delivery.

    Science.gov (United States)

    2015-01-01

    The West Virginia Division of Highways (WV DOH) hosted a Peer Exchange to share information and experiences : for streamlining Highway Safety Improvement Program (HSIP) project delivery. The event was held September : 22 to 23, 2014 in Charleston, We...

  3. Stagnating energy efficiency in the Swedish building sector-Economic and organisational explanations

    International Nuclear Information System (INIS)

    Naessen, Jonas; Sprei, Frances; Holmberg, John

    2008-01-01

    The development towards higher energy efficiency in the Swedish building sector stagnated in the late 1980s and 1990s. In new buildings the average specific energy use for heating is twice as high as in the best performing buildings 20 years ago. By combining econometric studies and interviews with actors in the building sector we analyse the underlying economic and organisational causes for this development. In the stock of buildings, specific energy use for heating (kWh/m 2 /yr) has a high correlation with increasing energy prices and price elasticities have not changed markedly over time. This implies that the stagnation to a large extent can be explained by energy price trends. On the contrary, in new buildings the correlation between energy prices and specific energy use is much weaker. One important cause of low sensitivity to price changes is that information about the life cycle cost (LCC) of different investment alternatives is often not available to the involved actors. The most common investment criterion is instead the requirements of the national building energy standard which has developed into a norm rather than a minimum for energy performance. In this paper we also discuss potential improvements in the learning processes within the sector

  4. Impacts of Anthropogenic Aerosols on Regional Climate: Extreme Events, Stagnation, and the United States Warming Hole

    Science.gov (United States)

    Mascioli, Nora R.

    temperature response pattern in AER and GHG is characterized by strong responses over the western U.S. and weak or opposite signed responses over the southeast U.S., raising the question of whether the observed U.S. "warming hole" could have a forced component. To address this question, I systematically examine observed seasonal temperature trends over all time periods of at least 10 years during 1901-2015. In the northeast and southern U.S., significant summertime cooling occurs from the early 1950s to the mid 1970s, which I partially attribute to increasing anthropogenic aerosol emissions (median fraction of the observed temperature trends explained is 0.69 and 0.17, respectively). In winter, the northeast and southern U.S. cool significantly from the early 1950s to the early 1990s, which I attribute to long-term phase changes in the North Atlantic Oscillation and the Pacific Decadal Oscillation. Rather than being a single phenomenon stemming from a single cause, both the warming hole and its dominant drivers vary by season, region, and time period. Finally, I examine historical and projected future changes in atmospheric stagnation. Stagnation, which is characterized by weak winds and an absence of precipitation, is a meteorological contributor to heat waves, extreme pollution, and drought. Using CM3, I show that regional stagnation trends over the historical period (1860-2005) are driven by changes in anthropogenic aerosol emissions, rather than rising greenhouse gases. In the northeastern and central United States, aerosol-induced changes in surface and upper level winds produce significant decreases in the number of stagnant summer days, while decreasing precipitation in the southeast US increases the number of stagnant summer days. Outside of the U.S., significant drying over eastern China in response to rising aerosol emissions contributed to increased stagnation during 1860-2005. Additionally, this region was found to be particularly sensitive to changes in local

  5. International health policy and stagnating maternal mortality: is there a causal link?

    Science.gov (United States)

    Unger, Jean-Pierre; Van Dessel, Patrick; Sen, Kasturi; De Paepe, Pierre

    2009-05-01

    This paper examines why progress towards Millennium Development Goal 5 on maternal health appears to have stagnated in much of the global south. We contend that besides the widely recognised existence of weak health systems, including weak services, low staffing levels, managerial weaknesses, and lack of infrastructure and information, this stagnation relates to the inability of most countries to meet two essential conditions: to develop access to publicly funded, comprehensive health care, and to provide the not-for-profit sector with needed political, technical and financial support. This paper offers a critical perspective on the past 15 years of international health policies as a possible cofactor of high maternal mortality, because of their emphasis on disease control in public health services at the expense of access to comprehensive health care, and failures of contracting out and public-private partnerships in health care. Health care delivery cannot be an issue both of trade and of right. Without policies to make health systems in the global south more publicly-oriented and accountable, the current standards of maternal and child health care are likely to remain poor, and maternal deaths will continue to affect women and their families at an intolerably high level.

  6. Stagnation of the exploitation of Al ores and the depression of world prices of Al

    Directory of Open Access Journals (Sweden)

    Slavkovský Jozef

    1999-03-01

    Full Text Available In the contribution, data on Al – a metal of the 20th century are compiled together with the problems of genesis of the Al mineral raw ma-terials as well as types of bauxite and Al-laterite deposits. Furthermore, an overview of the world exploitation of bauxite during 1935-1980 is given along with the prognoses to 2000 and present situation (1992-1996. Overviews of the production of Al follows, providing its rela-tion to the bauxite exploitation. Contrary to the prognoses, a stabilization or stagnation has been observed in the exploitation of bauxite and production of Al during nineties, which a tendency is directly reflected in the world price of this commodity. When analyzing the Al prices for a longer period, some serious deviations can be noticed, that however presently represent a long-term minimum. We hope the stagnation of the production and the price decline are only temporary and new possibilities of the utilization of Al will be found soon.

  7. Variations in the Spatial Distribution of Areas of Economic Growth and Stagnation in Poland: Determinants and Consequences

    Directory of Open Access Journals (Sweden)

    Churski Paweł

    2014-06-01

    Full Text Available This study seeks to identify the spatial distribution of and changes in areas of economic growth and stagnation in Poland resulting from spatial differences in the process of the country’s socio-economic advancement. The research covered two spatial systems, NUTS 2 and NUTS 4, and embraced the following steps: (1 identification of the spatial distribution of areas of economic growth and stagnation, by region and subregion, and of its determinants; (2 analysis of variations in the spatial distribution of areas of economic growth and stagnation, by region and subregion, and of its consequences; and (3 conclusions from the development trajectories identified and recommendations for intervention measures to be taken under cohesion policy.

  8. Effectiveness of and obstacles to antibiotic streamlining to amoxicillin monotherapy in bacteremic pneumococcal pneumonia.

    Science.gov (United States)

    Blot, Mathieu; Pivot, Diane; Bourredjem, Abderrahmane; Salmon-Rousseau, Arnaud; de Curraize, Claire; Croisier, Delphine; Chavanet, Pascal; Binquet, Christine; Piroth, Lionel

    2017-09-01

    Antibiotic streamlining is pivotal to reduce the emergence of resistant bacteria. However, whether streamlining is frequently performed and safe in difficult situations, such as bacteremic pneumococcal pneumonia (BPP), has still to be assessed. All adult patients admitted to Dijon Hospital (France) from 2005 to 2013 who had BPP without complications, and were alive on the third day were enrolled. Clinical, biological, radiological, microbiological and therapeutic data were recorded. A first analysis was conducted to assess factors associated with being on amoxicillin on the third day. A second analysis, adjusting for a propensity score, was performed to determine whether 30-day mortality was associated with streamlining to amoxicillin monotherapy. Of the 196 patients hospitalized for BPP, 161 were still alive on the third day and were included in the study. Treatment was streamlined to amoxicillin in 60 patients (37%). Factors associated with not streamlining were severe pneumonia (OR 3.11, 95%CI [1.23-7.87]) and a first-line antibiotic combination (OR 3.08, 95%CI [1.34-7.09]). By contrast, starting with amoxicillin monotherapy correlated inversely with the risk of subsequent treatment with antibiotics other than amoxicillin (OR 0.06, 95%CI [0.01-0.30]). The Cox model adjusted for the propensity-score analysis showed that streamlining to amoxicillin during BPP was not significantly associated with a higher risk of 30-day mortality (HR 0.38, 95%CI [0.08-1.87]). Streamlining to amoxicillin is insufficiently implemented during BPP. This strategy is safe and potentially associated with ecological and economic benefits; therefore, it should be further encouraged, particularly when antibiotic combinations are started for severe pneumonia. Copyright © 2017. Published by Elsevier B.V.

  9. The Chinese medicine construct "stagnation" in mind-body connection mediates the effects of mindfulness training on depression and anxiety.

    Science.gov (United States)

    Lo, Herman H M; Ng, Siu Man; Chan, Cecilia L W; Lam, K F; Lau, Bobo H P

    2013-08-01

    Previous studies have identified different, but highly correlated variables explaining the effects of mindfulness training. Many of them are limited by tautological explanation. Under the framework of the mind-body connection, mindfulness training cultivates body awareness and promotes self-management of illness. Stagnation, a concept from Chinese medicine, may help explain the mechanism of change in mindfulness training. Individuals with depressive and anxiety symptoms (n=82) were randomized to either a Compassion-Mindfulness Therapy (C-MT) program or a waitlist control condition. The effect of stagnation as a mediator was investigated for dependent variables including depression, anxiety, and other physical and mental health variables. Depression, anxiety, stagnation, physical distress, daily functioning, positive affect, negative affect. Compared with the participants in the control group, those who completed C-MT demonstrated significant decreases in depression, F(1, 78)=15.67, p<.001, anxiety, F(1, 78)=7.72, p<.001, stagnation, F(1, 78)=4.96, p<.001, and other body-mind-spirit well-being measures. After entering the change in stagnation as the mediator, the effect of treatment reduced: depression (.35-.22), anxiety (.33-.05), and same patterns in other three secondary measures. The Sobel test was administered and significant reductions between group and depression (z=2.18, p=.029), anxiety (z=2.21, p=.027), and three secondary other measures (p<.05) were indicated. The study provides initial support for the role of stagnation in mediating changes in mindfulness training. It adds evidence to body-mind nondualism and offers new possibilities in studying treatment process and change mechanism. Copyright © 2013 Elsevier Ltd. All rights reserved.

  10. Real-Gas Correction Factors for Hypersonic Flow Parameters in Helium

    Science.gov (United States)

    Erickson, Wayne D.

    1960-01-01

    The real-gas hypersonic flow parameters for helium have been calculated for stagnation temperatures from 0 F to 600 F and stagnation pressures up to 6,000 pounds per square inch absolute. The results of these calculations are presented in the form of simple correction factors which must be applied to the tabulated ideal-gas parameters. It has been shown that the deviations from the ideal-gas law which exist at high pressures may cause a corresponding significant error in the hypersonic flow parameters when calculated as an ideal gas. For example the ratio of the free-stream static to stagnation pressure as calculated from the thermodynamic properties of helium for a stagnation temperature of 80 F and pressure of 4,000 pounds per square inch absolute was found to be approximately 13 percent greater than that determined from the ideal-gas tabulation with a specific heat ratio of 5/3.

  11. Inter-laboratory validation of an inexpensive streamlined method to measure inorganic arsenic in rice grain.

    Science.gov (United States)

    Chaney, Rufus L; Green, Carrie E; Lehotay, Steven J

    2018-05-04

    With the establishment by CODEX of a 200 ng/g limit of inorganic arsenic (iAs) in polished rice grain, more analyses of iAs will be necessary to ensure compliance in regulatory and trade applications, to assess quality control in commercial rice production, and to conduct research involving iAs in rice crops. Although analytical methods using high-performance liquid chromatography-inductively coupled plasma-mass spectrometry (HPLC-ICP-MS) have been demonstrated for full speciation of As, this expensive and time-consuming approach is excessive when regulations are based only on iAs. We report a streamlined sample preparation and analysis of iAs in powdered rice based on heated extraction with 0.28 M HNO 3 followed by hydride generation (HG) under control of acidity and other simple conditions. Analysis of iAs is then conducted using flow-injection HG and inexpensive ICP-atomic emission spectroscopy (AES) or other detection means. A key innovation compared with previous methods was to increase the acidity of the reagent solution with 4 M HCl (prior to reduction of As 5+ to As 3+ ), which minimized interferences from dimethylarsinic acid. An inter-laboratory method validation was conducted among 12 laboratories worldwide in the analysis of six shared blind duplicates and a NIST Standard Reference Material involving different types of rice and iAs levels. Also, four laboratories used the standard HPLC-ICP-MS method to analyze the samples. The results between the methods were not significantly different, and the Horwitz ratio averaged 0.52 for the new method, which meets official method validation criteria. Thus, the simpler, more versatile, and less expensive method may be used by laboratories for several purposes to accurately determine iAs in rice grain. Graphical abstract Comparison of iAs results from new and FDA methods.

  12. Connecting streamlined subglacial bedforms with the geological/geographical environment in which they are located.

    Science.gov (United States)

    Dowling, Tom; Möller, Per; Greenwood, Sarah; Spagnolo, Matteo; Åkesson, Maria; Fraser, Stephen; Hughs, Anna; Clark, Chris

    2016-04-01

    Much work has qualitatively shown that there appears to be a relationship between the morphology of streamlined subglacial bedforms (drumlinoids) and the geological/geographical environment in which said bedforms are located upon, particularly in terms of bedrock influence. However, the one quantitative study that has been carried out on this connectivity (Greenwood and Clark, 2010) found that there appears to be a connection between bedrock type and morphology only at a local scale. At a regional scale the most important geological factor seemed to be the properties of the substrate, usually till. In order to investigate these connections further, self-organising maps (SOM) are used to investigate the role of contextual geology/geography in drumlinoid morphology. The SOM method allows the statistical exploration of data that cannot normally be evaluated by traditional means; categorical data (e.g. bedrock type) can be used in the same analysis as continuous/vector data (e.g. drift depth). Here, three large morphological data sets from Sweden (20 041), Britain (36 104) and Ireland (13 454) are combined with bedrock type, drift depth, basal elevation and distance to esker to see if there are any relationships to be found between them. The results indicate that there are pervasive, statistically significant, and weak to very weak correlations between contextual geological/geographical factors and drumlinoid morphology. The most important contextual factor appears to be 'drift depth', followed by 'distance to esker'. Therefore, models of drumlinoid formation and any efforts to use such features for palaeo-ice reconstruction must take into account the geological and geographical environment in which they are situated. The logical extension of this is that models of ice-sheet growth and retreat must also take into account and be sensitive to the type of substratum present beneath the ice. Further research into the effect of drift properties on the flow of ice is needed.

  13. Gas-liquid flow around an obstacle in a vertical pipe

    International Nuclear Information System (INIS)

    Prasser, Horst-Michael; Beyer, Matthias; Frank, Thomas; Al Issa, Suleiman; Carl, Helmar; Pietruske, Heiko; Schuetz, Peter

    2008-01-01

    This paper presents a novel technique to study the two-phase flow field around an asymmetric obstruction in a vertical pipe with a nominal diameter of DN200. Main feature of the experiments is the shifting of a half-moon shaped diaphragm causing the obstruction along the axis of the pipe. In this way, the 3D void field is scanned with a stationary wire-mesh sensor that supplies data with a spatial resolution of 3 mm over the cross-section and a measuring frequency of 2.5 kHz. Besides the measurement of time-averaged void fraction fields and bubble-size distributions, novel data evaluation methods were developed to extract estimated liquid velocity profiles as well as lateral components of bubble velocities from the wire-mesh sensor data. The combination of void fraction fields and velocity profiles offer the opportunity to analyse a two-phase flow in a geometry that owns a series of features characteristic for complex components of power and chemical plant equipment. Such characteristics are sharp edges with flow separation, recirculation areas, jet formation, stagnation points and curved stream-lines. The tests were performed with an air-water flow at nearly ambient conditions and with a saturated steam-water mixture at 6.5 MPa. The superficial velocities of liquid and gas or, respectively, vapour were varied in a wide range. The flow structure upstream and downstream of the obstacle is characterized in detail. Bubble size dependent effects of bubble accumulation and migration are discussed on basis of void-fraction profiles decomposed into bubble-size classes. A pronounced influence of the fluid parameters was found in the behaviour of bubbles at the boundary of the jet coming from the non-obstructed part of the cross-section. In case of an air-water flow, bubbles are restrained from entering the jet, a phenomenon which was not observed in high-pressure steam-water flow. A detailed uncertainty analyse of the velocity assessments finishes the presented paper. A

  14. Hall effect on magnetohydrodynamic instabilities at an elliptic magnetic stagnation line

    Science.gov (United States)

    Spies, Günther O.; Faghihi, Mustafa

    1987-06-01

    To answer the question whether the Hall effect removes the unphysical feature of ideal magnetohydrodynamics of predicting small wavelength kink instabilities at any elliptic magnetic stagnation line, a normal mode analysis is performed of the motion of an incompressible Hall fluid about cylindrical Z-pinch equilibria with circular cross sections. The eigenvalue loci in the complex frequency plane are derived for the equilibrium with constant current density. Every particular mode becomes stable as the Hall parameter exceeds a critical value. This value, however, depends on the mode such that it increases to infinity as the ideal growth rate decreases to zero, implying that there always remains an infinite number of slowly growing instabilities. Correspondingly, the stability criterion for equilibria with arbitrary current distributions is independent of the Hall parameter.

  15. Hall effect upon small wavelength kink instabilities near an elliptic magnetic stagnation line

    International Nuclear Information System (INIS)

    Spies, G.O.; Faghihi, M.

    1985-12-01

    To explore the question whether the Hall effect removes the unphysical feature of ideal magnetohydrodynamics of predicting unstable small wavelenght kinks near any elliptic magnetic stagnation line, a spectral analysis is performed of the motion of an incompressible plasma about cylindrical Z-pinch equilibria with circular sections. The eigenvalue loci in the complex frequency plane are derived for the equilibrium with constant current density. These show that every particular mode becomes stable as the Hall parameter exceeds a critical value. However, this critical value is a decreasing function of the ideal growth rate and has a pole at the origin, implying that there always remains an infinite reservoir of slowly growing instabilities. Correspondingly, for equilibiria with arbitrary current distributions, the stability criterion is unaffected by the Hall term. (author)

  16. Hall effect on magnetohydrodynamic instabilities at an elliptic magnetic stagnation line

    International Nuclear Information System (INIS)

    Spies, G.O.; Faghihi, M.

    1987-01-01

    To answer the question whether the Hall effect removes the unphysical feature of ideal magnetohydrodynamics of predicting small wavelength kink instabilities at any elliptic magnetic stagnation line, a normal mode analysis is performed of the motion of an incompressible Hall fluid about cylindrical Z-pinch equilibria with circular cross sections. The eigenvalue loci in the complex frequency plane are derived for the equilibrium with constant current density. Every particular mode becomes stable as the Hall parameter exceeds a critical value. This value, however, depends on the mode such that it increases to infinity as the ideal growth rate decreases to zero, implying that there always remains an infinite number of slowly growing instabilities. Correspondingly, the stability criterion for equilibria with arbitrary current distributions is independent of the Hall parameter

  17. 3D Stagnation instabilities in MagLIF loads on the Z Generator

    Science.gov (United States)

    Jennings, Christopher

    2017-10-01

    Experiments with Magnetized Liner Inertial Fusion (MagLIF) loads have successfully demonstrated the premise of magnetized fusion. While these experiments are increasingly well diagnosed, many of the measurements (particularly during stagnation) are time integrated, limited in spatial resolution or require additional assumptions to interpret in the context of a structured, rapidly evolving system. As such, there is some ambiguity over what may be limiting performance. Poor laser coupling in preheating the fuel prior to implosion has been suggested as a mechanism. Mix of high Z contaminants that cool the fuel is also a significant concern. In addition, time integrated crystal imaging has shown significant structure in the final fuel assembly indicating potential disruption from instabilities. Understanding the balance between these degradation mechanisms is vital to progress with MagLif. We compare several sets of experimental data with synthetically generated data from systematically varied 3D resistive-MHD simulations to gain insight into the relative contributions of different degradation mechanisms. We demonstrate how some measurements strongly indicate disruption from liner material penetrating into the fuel at stagnation, and discuss the implications this has for how MagLif targets work and scale to larger drive currents. We then explore the extent to which different combinations of instability development, current delivery, high-Z mix into the fuel and initial laser deposition can be differentiated in our existing measurements. Better determining the dominant degradation mechanisms can directly influence the direction we take to improve performance, or our confidence in scaling these targets to higher currents. Sandia National Laboratories is a multimission laboratory managed and operated by National Technology and Engineering Solutions of Sandia LLC, a wholly owned subsidiary of Honeywell International Inc. for the U.S. DoE's NNSA under contract DE-NA0003525.

  18. Overcoming Stagnation in the Levels and Distribution of Child Mortality: The Case of the Philippines.

    Directory of Open Access Journals (Sweden)

    Raoul Bermejo

    Full Text Available Health-related within-country inequalities continue to be a matter of great interest and concern to both policy makers and researchers. This study aims to assess the level and the distribution of child mortality outcomes in the Philippines across geographical and socioeconomic indicators.Data on 159,130 children ever borne were analysed from five waves of the Philippine Demographic and Health Survey. Direct estimation was used to construct under-five and neonatal mortality rates for the period 1980-2013. Rate differences and ratios, and where possible, slope and relative indices of inequality were calculated to measure disparities on absolute and relative scales. Stratification was undertaken by levels of rural/urban location, island groups and household wealth.National under-five and neonatal mortality rates have shown considerable albeit differential reductions since 1980. Recently released data suggests that neonatal mortality has declined following a period of stagnation. Declines in under-five mortality have been accompanied by decreases in wealth and geography-related absolute inequalities. However, relative inequalities for the same markers have remained stable over time. For neonates, mixed evidence suggests that absolute and relative inequalities have remained stable or may have risen.In addition to continued reductions in under-five mortality, new data suggests that the Philippines have achieved success in addressing the commonly observed stagnated trend in neonatal mortality. This success has been driven by economic improvement since 2006 as well as efforts to implement a nationwide universal health care campaign. Yet, such patterns, nonetheless, accorded with persistent inequalities, particularly on a relative scale. A continued focus on addressing universal coverage, the influence of decentralisation and armed conflict, and issues along the continuum of care is advocated.

  19. Mass conservative fluid flow visualization for CFD velocity fields

    International Nuclear Information System (INIS)

    Li, Zhenquan; Mallinson, Gordon D.

    2001-01-01

    Mass conservation is a key issue for accurate streamline and stream surface visualization of flow fields. This paper complements an existing method (Feng et al., 1997) for CFD velocity fields defined at discrete locations in space that uses dual stream functions to generate streamlines and stream surfaces. Conditions for using the method have been examined and its limitations defined. A complete set of dual stream functions for all possible cases of the linear fields on which the method relies are presented. The results in this paper are important for developing new methods for mass conservative streamline visualization from CFD data and using the existing method

  20. Fluorescence Imaging and Streamline Visualization of Hypersonic Flow over Rapid Prototype Wind-Tunnel Models

    Science.gov (United States)

    Danehy, Paul M.; Alderfer, David W.; Inman, Jennifer A.; Berger, Karen T.; Buck, Gregory M.; Schwartz, Richard J.

    2008-01-01

    Reentry models for use in hypersonic wind tunnel tests were fabricated using a stereolithography apparatus. These models were produced in one day or less, which is a significant time savings compared to the manufacture of ceramic or metal models. The models were tested in the NASA Langley Research Center 31-Inch Mach 10 Air Tunnel. Only a few of the models survived repeated tests in the tunnel, and several failure modes of the models were identified. Planar laser-induced fluorescence (PLIF) of nitric oxide (NO) was used to visualize the flowfields in the wakes of these models. Pure NO was either seeded through tubes plumbed into the model or via a tube attached to the strut holding the model, which provided localized addition of NO into the model s wake through a porous metal cylinder attached to the end of the tube. Models included several 2- inch diameter Inflatable Reentry Vehicle Experiment (IRVE) models and 5-inch diameter Crew Exploration Vehicle (CEV) models. Various model configurations and NO seeding methods were used, including a new streamwise visualization method based on PLIF. Virtual Diagnostics Interface (ViDI) technology, developed at NASA Langley Research Center, was used to visualize the data sets in post processing. The use of calibration "dotcards" was investigated to correct for camera perspective and lens distortions in the PLIF images.

  1. Going with the flow: Implementing a workflow system to streamline acquisitions in a special library

    CSIR Research Space (South Africa)

    Halland, Y

    2004-05-01

    Full Text Available and used CSIRIS staff within the business units as “guinea pigs”. Some refinement was done on the basis of the feedback received from them before a few end-users were asked to test the system as well. The testing period was limited as CS had other...

  2. Economics of thinning stagnated ponderosa pine sapling stands in the pine-grass areas of central Washington.

    Science.gov (United States)

    Robert W. Sassaman; James W. Barrett; Justin G. Smith

    1972-01-01

    Present net worth values earned by investments in precommercial thinning of stagnated ponderosa pine sapling stands are reported for three stocking levels. Thirteen timber management regimes are ranked by their returns from timber only, and 22 regimes are ranked according to their returns from timber and forage, with and without the allowable cut effect.

  3. Influence of secondary flow on meandring of rivers

    NARCIS (Netherlands)

    Olesen, K.W.

    1982-01-01

    A linear stability analysis of the governing equations for the bed and flow topography in straight alluvial channels is treated. The flow is described by a horizontal two-dimensional model, but secondary flow due to curvature of the streamlines is included. Further more knowledge about secondary

  4. Streamlining Transportation Corridor Planning Processess: Freight and Traffic Information

    Energy Technology Data Exchange (ETDEWEB)

    Franzese, Oscar [ORNL

    2010-08-01

    The traffic investigation is one of the most important parts of an Environmental Impact Statement of projects involving the construction of new roadway facilities and/or the improvement of existing ones. The focus of the traffic analysis is on the determination of anticipated traffic flow characteristics of the proposed project, by the application of analytical methods that can be grouped under the umbrella of capacity analysis methodologies. In general, the main traffic parameter used in EISs to describe the quality of traffic flow is the Level of Service (LOS). The current state of the practice in terms of the traffic investigations for EISs has two main shortcomings. The first one is related to the information that is necessary to conduct the traffic analysis, and specifically to the lack of integration among the different transportation models and the sources of information that, in general, reside in GIS databases. A discussion of the benefits of integrating CRS&SI technologies and the transportation models used in the EIS traffic investigation is included. The second shortcoming is in the presentation of the results, both in terms of the appearance and formatting, as well as content. The presentation of traffic results (current and proposed) is discussed. This chapter also addresses the need of additional data, in terms of content and coverage. Regarding the former, other traffic parameters (e.g., delays) that are more meaningful to non-transportation experts than LOS, as well as additional information (e.g., freight flows) that can impact traffic conditions and safety are discussed. Spatial information technologies can decrease the negative effects of, and even eliminate, these shortcomings by making the relevant information that is input to the models more complete and readily available, and by providing the means to communicate the results in a more clear and efficient manner. The benefits that the application and use of CRS&SI technologies can provide to

  5. Turbulence modeling for flows around convex features giving rapid eddy distortion

    International Nuclear Information System (INIS)

    Tucker, P.G.; Liu, Y.

    2007-01-01

    Reynolds averaged Navier-Stokes model performances in the stagnation and wake regions for turbulent flows with relatively large Lagrangian length scales (generally larger than the scale of geometrical features) approaching small cylinders (both square and circular) is explored. The effective cylinder (or wire) diameter based Reynolds number, Re W ≤ 2.5 x 10 3 . The following turbulence models are considered: a mixing-length; standard Spalart and Allmaras (SA) and streamline curvature (and rotation) corrected SA (SARC); Secundov's ν t -92; Secundov et al.'s two equation ν t -L; Wolfshtein's k-l model; the Explicit Algebraic Stress Model (EASM) of Abid et al.; the cubic model of Craft et al.; various linear k-ε models including those with wall distance based damping functions; Menter SST, k-ω and Spalding's LVEL model. The use of differential equation distance functions (Poisson and Hamilton-Jacobi equation based) for palliative turbulence modeling purposes is explored. The performance of SA with these distance functions is also considered in the sharp convex geometry region of an airfoil trailing edge. For the cylinder, with Re W ∼ 2.5 x 10 3 the mixing length and k-l models give strong turbulence production in the wake region. However, in agreement with eddy viscosity estimates, the LVEL and Secundov ν t -92 models show relatively little cylinder influence on turbulence. On the other hand, two equation models (as does the one equation SA) suggest the cylinder gives a strong turbulence deficit in the wake region. Also, for SA, an order or magnitude cylinder diameter decrease from Re W = 2500 to 250 surprisingly strengthens the cylinder's disruptive influence. Importantly, results for Re W W = 250 i.e. no matter how small the cylinder/wire its influence does not, as it should, vanish. Similar tests for the Launder-Sharma k-ε, Menter SST and k-ω show, in accordance with physical reality, the cylinder's influence diminishing albeit slowly with size. Results

  6. Streamlined Calibration of the ATLAS Muon Spectrometer Precision Chambers

    CERN Document Server

    Levin, DS; The ATLAS collaboration; Dai, T; Diehl, EB; Ferretti, C; Hindes, JM; Zhou, B

    2009-01-01

    The ATLAS Muon Spectrometer is comprised of nearly 1200 optically Monitored Drifttube Chambers (MDTs) containing 354,000 aluminum drift tubes. The chambers are configured in barrel and endcap regions. The momentum resolution required for the LHC physics reach (dp/p = 3% and 10% at 100 GeV and 1 TeV) demands rigorous MDT drift tube calibration with frequent updates. These calibrations (RT functions) convert the measured drift times to drift radii and are a critical component to the spectrometer performance. They are sensitive to the MDT gas composition: Ar 93%, CO2 7% at 3 bar, flowing through the detector at arate of 100,000 l hr−1. We report on the generation and application of Universal RT calibrations derived from an inline gas system monitor chamber. Results from ATLAS cosmic ray commissioning data are included. These Universal RTs are intended for muon track reconstuction in LHC startup phase.

  7. Streamlining the Online Course Development Process by Using Project Management Tools

    Science.gov (United States)

    Abdous, M'hammed; He, Wu

    2008-01-01

    Managing the design and production of online courses is challenging. Insufficient instructional design and inefficient management often lead to issues such as poor course quality and course delivery delays. In an effort to facilitate, streamline, and improve the overall design and production of online courses, this article discusses how we…

  8. Less is More : Better Compliance and Increased Revenues by Streamlining Business Registration in Uganda

    OpenAIRE

    Sander, Cerstin

    2003-01-01

    A pilot of a streamlined business registration system in Entebbe, Uganda, reduced compliance costs for enterprises by 75 percent, raised registration numbers and fee revenue by 40 percent and reduced the cost of administering the system. It also reduced opportunities for corruption, improved relations between businesses and the local authorities and resulted in better compliance.

  9. Zephyr: A secure Internet-based process to streamline engineering procurements using the World Wide Web

    Energy Technology Data Exchange (ETDEWEB)

    Jordan, C.W.; Cavitt, R.E.; Niven, W.A.; Warren, F.E.; Taylor, S.S.; Sharick, T.M.; Vickers, D.L.; Mitschkowetz, N.; Weaver, R.L.

    1996-08-13

    Lawrence Livermore National Laboratory (LLNL) is piloting an Internet- based paperless process called `Zephyr` to streamline engineering procurements. Major benefits have accrued by using Zephyr in reducing procurement time, speeding the engineering development cycle, facilitating industrial collaboration, and reducing overall costs. Programs at LLNL are benefiting by the efficiencies introduced since implementing Zephyr`s engineering and commerce on the Internet.

  10. The design of the Comet streamliner: An electric land speed record motorcycle

    Science.gov (United States)

    McMillan, Ethan Alexander

    The development of the land speed record electric motorcycle streamliner, the Comet, is discussed herein. Its design process includes a detailed literary review of past and current motorcycle streamliners in an effort to highlight the main components of such a vehicle's design, while providing baseline data for performance comparisons. A new approach to balancing a streamliner at low speeds is also addressed, a system henceforth referred to as landing gear, which has proven an effective means for allowing the driver to control the low speed instabilities of the vehicle with relative ease compared to tradition designs. This is accompanied by a dynamic stability analysis conducted on a test chassis that was developed for the primary purpose of understanding the handling dynamics of streamliners, while also providing a test bed for the implementation of the landing gear system and a means to familiarize the driver to the operation and handling of such a vehicle. Data gathered through the use of GPS based velocity tracking, accelerometers, and a linear potentiometer provided a means to validate a dynamic stability analysis of the weave and wobble modes of the vehicle through linearization of a streamliner model developed in the BikeSIM software suite. Results indicate agreement between the experimental data and the simulation, indicating that the conventional recumbent design of a streamliner chassis is in fact highly stable throughout the performance envelope beyond extremely low speeds. A computational fluid dynamics study was also performed, utilized in the development of the body of the Comet to which a series of tests were conducted in order to develop a shape that was both practical to transport and highly efficient. By creating a hybrid airfoil from a NACA 0018 and NACA 66-018, a drag coefficient of 0.1 and frontal area of 0.44 m2 has been found for the final design. Utilizing a performance model based on the proposed vehicle's motor, its rolling resistance, and

  11. Vortex flow in acoustically levitated drops

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Z.L.; Xie, W.J. [Department of Applied Physics, Northwestern Polytechnical University, Xi' an 710072 (China); Wei, B., E-mail: bbwei@nwpu.edu.cn [Department of Applied Physics, Northwestern Polytechnical University, Xi' an 710072 (China)

    2011-08-29

    The internal flow of acoustically levitated water drops is investigated experimentally. This study reveals a kind of vortex flow which rotates in the meridional plane of the levitated drop. The magnitude of fluid velocity is nearly vanishing at the drop center, whereas it increases toward the free surface of a levitated drop until the maximum value of about 80 mm/s. A transition of streamline shapes from concentric circles to ellipses takes place at the distance of about 1.2 mm from the drop center. The fluid velocity distribution is plotted as a function of polar angle for seven characteristic streamlines. -- Highlights: → We experimentally observe the internal flow of acoustically levitated water drops. → We present a fascinating structure of vortex flow inside the levitated water drop. → This vortex flow rotates around the drop center in the meridional plane. → Velocity distribution information of this vortex flow is quantitatively analyzed.

  12. Vortex flow in acoustically levitated drops

    International Nuclear Information System (INIS)

    Yan, Z.L.; Xie, W.J.; Wei, B.

    2011-01-01

    The internal flow of acoustically levitated water drops is investigated experimentally. This study reveals a kind of vortex flow which rotates in the meridional plane of the levitated drop. The magnitude of fluid velocity is nearly vanishing at the drop center, whereas it increases toward the free surface of a levitated drop until the maximum value of about 80 mm/s. A transition of streamline shapes from concentric circles to ellipses takes place at the distance of about 1.2 mm from the drop center. The fluid velocity distribution is plotted as a function of polar angle for seven characteristic streamlines. -- Highlights: → We experimentally observe the internal flow of acoustically levitated water drops. → We present a fascinating structure of vortex flow inside the levitated water drop. → This vortex flow rotates around the drop center in the meridional plane. → Velocity distribution information of this vortex flow is quantitatively analyzed.

  13. An improved design of axially driven permanent maglev centrifugal pump with streamlined impeller.

    Science.gov (United States)

    Qian, K X; Zeng, P; Ru, W M; Yuan, H Y

    2007-01-01

    In 1839, Earnshaw proved theoretically that it is impossible to achieve a stable equilibrium with a pure permanent maglev. Furthermore, in 1939, Braunbeck deduced that it is only possible to stabilize a super conductive or an electric maglev. In 2000, however, the present authors discovered that stable levitation is achievable by a combination of permanent magnetic and nonmagnetic forces, and its stability can be maintained even with mere passive magnetic forces by use of the gyro-effect. An improved design of permanent maglev impeller pump has been developed. Passive magnetic (PM) bearings support the rotor radially; on its right side, an impeller is fixed and on its left side a motor magnets-assemble is mounted. Unlike a previous prototype design, in which the rotor magnets were driven by a motor via magnetic coupling, a motor coil is installed opposite to the motor magnets disc, producing a rotating magnetic field. At standstill or if the rotating speed is lower than 4000 rpm, the rotor has one axial point contact with the motor coil. The contact point is located at the centre of the rotor. As the rotating speed increases gradually to higher than 4000 rpm, the rotor will be drawn off from the contact point by the hydrodynamic force of the fluid. Then the rotor becomes fully suspended. For radial and peripheral stabilization, a gyro-effect is important, which is realized by designing the motor magnets disc to have large diameter, short length and high rotating speed; for axial stability, an axial rehabilitating force is necessary, which is produced by PM bearings. The rotor demonstrated a full levitation by rotation over 4000 rpm. As a left ventricular assist device, the rotation of the pump has a speed range from 5000 to 8000 rpm. The relation between pressure head and flow rate indicates that there is neither mechanical friction nor hydrodynamic turbulence inside the pump; the former is due to the frictionless maglev and the latter is a result of the

  14. Oxidation of iridium coating on rhenium coated graphite at elevated temperature in stagnated air

    International Nuclear Information System (INIS)

    Huang, Yongle; Bai, Shuxin; Zhang, Hong; Ye, Yicong

    2015-01-01

    Highlights: • Continuous and dense Ir coatings were prepared on graphite by electrodepostion. • The purification of the as-prepared Ir coating was higher than about 99.98%. • The Ir/Re/C specimen kept integrity without significant failures after oxidation. • The average oxidation rate of the Ir coating was about 0.219 mg/(cm 2 min). • Penetrating holes at gains boundaries resulted in the failure of the Ir coating. - Abstract: Continuous and dense iridium coatings were prepared on the rhenium coated graphite specimens by electrodeposition. The iridium/rhenium coated graphite (Ir/Re/C) specimens were oxidized at elevated temperatures in stagnated air for 3600 s. The purification of the as-prepared Ir coating was higher than about 99.98% with the main impurity elements Si, Al, Fe and Ru. After oxidation, the Ir/Re/C specimens kept integrity without significant failures and the average oxidation rate was about 0.219 mg/(cm 2 min). Pores were found at the grain boundaries and concentrated to penetrating holes with the growth of Ir grains, which resulted in disastrous failures of the Ir coating

  15. Oxidation of iridium coating on rhenium coated graphite at elevated temperature in stagnated air

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Yongle; Bai, Shuxin, E-mail: NUDT_MSE_501@163.com; Zhang, Hong; Ye, Yicong

    2015-02-15

    Highlights: • Continuous and dense Ir coatings were prepared on graphite by electrodepostion. • The purification of the as-prepared Ir coating was higher than about 99.98%. • The Ir/Re/C specimen kept integrity without significant failures after oxidation. • The average oxidation rate of the Ir coating was about 0.219 mg/(cm{sup 2} min). • Penetrating holes at gains boundaries resulted in the failure of the Ir coating. - Abstract: Continuous and dense iridium coatings were prepared on the rhenium coated graphite specimens by electrodeposition. The iridium/rhenium coated graphite (Ir/Re/C) specimens were oxidized at elevated temperatures in stagnated air for 3600 s. The purification of the as-prepared Ir coating was higher than about 99.98% with the main impurity elements Si, Al, Fe and Ru. After oxidation, the Ir/Re/C specimens kept integrity without significant failures and the average oxidation rate was about 0.219 mg/(cm{sup 2} min). Pores were found at the grain boundaries and concentrated to penetrating holes with the growth of Ir grains, which resulted in disastrous failures of the Ir coating.

  16. Stable isotopic fractionation, climate change and episodic stagnation in the eastern Mediterranean during the late Quaternary

    Energy Technology Data Exchange (ETDEWEB)

    Vergnaud-Grazzini, C [Laboratoire de Geologie Dynamique, Paris (France); Ryan, W B.F. [Columbia Univ., Palisades, NY (USA). Lamont-Doherty Geological Observatory; Cita, M B [Milan Univ. (Italy)

    1977-11-01

    Fluctuations in the delta/sup 18/O composition of planktonic foraminifers in eastern Mediterranean piston cores indicate cycles with amplitudes much greater than those which can be attributed alone to global ice-volume changes. Isotopic values become markedly negative within lithostratigraphic levels characterized by the apparition of organic-rich sapropels. These owe their origin to the development of euxinic bottom water during episodes of basin-wide stagnation. The depletion of delta/sup 18/O in many of the sapropels is accompanied by the occurrence of poorly diversified planktonic faunas, and both phenomena are attributed to a strong dilution of the local eastern Mediterranean surface water mass by a combination of glacial run off from large continental ice sheets and by an important increase of regional precipitation synchronous with the transition from pleniglacial to kataglacial climate. Although sapropel accumulation occurs generally during intervals of warming of the Mediterranean region as determined from a quantitative evaluation of planktonic foraminiferal assemblages, the pre-125,000 years, local warming of eastern Mediterranean surface water lagged the acme of glacial melting by up to 15,000 years. Climatic and isotopic cycles are correlative within the eastern Mediterranean for lateral distances in excess of 1000 km and, except for amplitude and phase, they are in most aspects remarkably similar to those recorded in the equatorial Pacific and Caribbean.

  17. Diagnosing the Stagnation Conditions of MagLIF Implosions Using Co and Kr dopants

    Science.gov (United States)

    Harding, E. C.; Hansen, S. B.; Harvey-Thompson, A. J.; Weis, M. R.; Hahn, K. D.; Gomez, M. R.; Knapp, P. F.; Slutz, S. A.; Geissel, M.; Ampleford, D. J.; Jennings, C. A.; Peterson, K.; Rochau, G. A.; Doron, R.; Stambulchik, E.; Nedostup, O.; Maron, Y.; Golovkin, I.

    2017-10-01

    Recent experiments on the Z-machine tested several new diagnostic techniques for investigating the stagnation conditions and the origins of the mix present in a Magnetized Liner Inertial Fusion (MagLIF) target. For the first time we have collected K-shell spectra from a low-concentration, Kr dopant placed in the gaseous D2 fuel. In addition, thin Co coatings were strategically applied to three different internal surfaces of the target in order to assess which surfaces actively contribute to the contamination of the fuel. Both imaging spectroscopy and narrow-band crystal imaging were used to identify the location of He-like Co ions. The Te and ne of the Co is inferred by fitting the He-alpha lines and the near-by Li-like satellites. The experimental measurements and the challenges associated with the analysis will be discussed. Sandia Natl Lab is a multi-mission laboratory managed and operated by National Technology and Engineering Solutions of Sandia, LLC., a wholly owned subsidiary of Honeywell International, Inc., for the U.S. DOE NNSA under contract DE-NA-0003525.

  18. 2-D simulations of the implosion, collapse and stagnation of laser fusion shells

    International Nuclear Information System (INIS)

    Atzeni, S.; Guerrieri, A.

    1989-01-01

    We discuss the method, model and first results of 2-D numerical simulations of the entire history of gas-filled shells irradiated by laser pulses with long wavelength non-uniformities. Although this issue has already been addressed in connection with the design of reactor targets, or with the interpretation of experimental results, a complete, clear, and quantitative picture of the relevant phenomenology is still missing. In general, the history of a target can be divided into three phases, namely, the acceleration and inertial phase of the implosion (I;t≤t 0 ), the shock collapse and reflection (II,t 0 ≤t≤t ' 0 ) and the stagnation (t ' 0 ≤t≤t 1 ). In a previous study, we were able to study quantitatively phase I and to get some qualitative information on phase II. At t≅t 0 , however, negative area zones occurred in the mesh of our purely Lagrangian code, and the simulations became unreliable. We have now upgraded our code, by introducing an automatic mesh-rezoning package, which allows us to follow with reasonable accuracy phase II and III of the target implosion. (author) 9 refs., 6 figs

  19. Proton imaging of hohlraum plasma stagnation in inertial-confinement-fusion experiments

    International Nuclear Information System (INIS)

    Li, C.K.; Séguin, F.H.; Frenje, J.A.; Sinenian, N.; Rosenberg, M.J.; Manuel, M.J.-E; Rinderknecht, H.G.; Zylstra, A.B.; Petrasso, R.D.; Amendt, P.A.; Landen, O.L.; Mackinnon, A.J.; Town, R.P.J.; Wilks, S.C.; Betti, R.; Meyerhofer, D.D.; Soures, J.M.; Hund, J.; Kilkenny, J.D.; Nikroo, A.

    2013-01-01

    Proton radiography of the spatial structure and temporal evolution of plasma blowing off from a hohlraum wall reveals how the fill gas compresses the wall blow-off, inhibits plasma jet formation and impedes plasma stagnation in the hohlraum interior. The roles of spontaneously generated electric and magnetic fields in hohlraum dynamics and capsule implosions are demonstrated. The heat flux is shown to rapidly convect the magnetic field due to the Nernst effect, which is shown to be ∼10 times faster than convection by the plasma fluid from expanded wall blow-off (v N ∼ 10v). This leads to inhibition of heat transfer from the gas region in the laser beam paths to the surrounding cold gas, resulting in a local plasma temperature increase. The experiments show that interpenetration of the two materials (gas and wall) occurs due to the classical Rayleigh–Taylor instability as the lighter, decelerating ionized fill gas pushes against the heavier, expanding gold wall blow-off. This experiment provides physics insight into the effects of fill gas on x-ray-driven implosions, and would impact the ongoing ignition experiments at the National Ignition Facility. (paper)

  20. New Stagnation Arc Jet Model Design for Testing ADEPT 3-D Carbon Cloth

    Science.gov (United States)

    Beck, R.; Chen, Y.-K.; Wercinski, P.; Agrawal, P.; Chavez-Garcia, J.

    2017-01-01

    The ADEPT concept has been considered as an entry, descent and landing system to enable Human Mars class missions. Ground rules for the Mars studies required aerocapture, orbit, and then entry. The design utilizes a 3-D woven carbon cloth fabric as both heatshield and primary structure and design guidelines required 6 layers remaining after all entry events. The peak heating predicted for the ADEPT carbon cloth was 35 Wcm2 and resulting temperatures were predicted to be 1400K. Predictions for carbon mass loss were performed using equilibrium thermochemistry, which is only accurate for T2000K. Carbon oxidation is kinetically controlled at T2000K, and mass loss drops off considerably from equilibrium values. Design of the cloth thickness and mass would be significantly reduced if kinetics were considered. This effort was to design a stagnation test article design that could be used in the AHF with varying levels of oxygen where the results could be used to develop an engineering model to describe the recession rate of the carbon as a function of the partial pressure of monotomic oxygen.

  1. Temperature measurement in the flowing medium

    Directory of Open Access Journals (Sweden)

    Sedlák Kamil

    2018-01-01

    Full Text Available The article deals with a brief description of methods of temperature measurements in a flowing water steam. Attention is paid to the measurement of pseudo static temperature by a single sealed thermocouple entering the flowing liquid through the flown-by wall. Then three types of probes for stagnation temperature measurement are shown, whose properties were tested using CFD calculations. The aim was to design a probe of stagnation parameters of described properties which can be used for measuring flow parameters in a real steam turbine. An important factor influencing the construction is not only the safe manipulation of the probe when inserting and removing it from the machine in operation, but also the possibility to traverse the probe along the blade length.

  2. The role of atmospheric nuclear explosions on the stagnation of global warming in the mid 20th century

    Science.gov (United States)

    Fujii, Yoshiaki

    2011-04-01

    This study suggests that the cause of the stagnation in global warming in the mid 20th century was the atmospheric nuclear explosions detonated between 1945 and 1980. The estimated GST drop due to fine dust from the actual atmospheric nuclear explosions based on the published simulation results by other researchers (a single column model and Atmosphere-Ocean General Circulation Model) has served to explain the stagnation in global warming. Atmospheric nuclear explosions can be regarded as full-scale in situ tests for nuclear winter. The non-negligible amount of GST drop from the actual atmospheric explosions suggests that nuclear winter is not just a theory but has actually occurred, albeit on a small scale. The accuracy of the simulations of GST by IPCC would also be improved significantly by introducing the influence of fine dust from the actual atmospheric nuclear explosions into their climate models; thus, global warming behavior could be more accurately predicted.

  3. The stagnation of the Mexican male life expectancy in the first decade of the 21st century

    DEFF Research Database (Denmark)

    Canudas-Romo, Vladimir; García-Guerrero, Víctor Manuel; Echarri-Cánovas, Carlos Javier

    2015-01-01

    OBJECTIVES: In the first decade of the 21st century, the Mexican life expectancy changed from a long trend of increase to stagnation. These changes concur with an increase in deaths by homicides that the country experienced in that decade, and an obesity epidemic that had developed over the last...... of life expectancy from 2000 to 2010. RESULTS: The apparent stagnation in life expectancy is the result of an increase in deaths by homicides and diabetes mellitus on the one hand, and the positive improvements observed in other causes of death on the other. The negative impact of homicides...... by 2 years if deaths by homicides and diabetes mellitus had been avoided....

  4. Climatic and technological ceilings for Chinese rice stagnation based on yield gaps and yield trend pattern analysis.

    Science.gov (United States)

    Zhang, Tianyi; Yang, Xiaoguang; Wang, Hesong; Li, Yong; Ye, Qing

    2014-04-01

    Climatic or technological ceilings could cause yield stagnation. Thus, identifying the principal reasons for yield stagnation within the context of the local climate and socio-economic conditions are essential for informing regional agricultural policies. In this study, we identified the climatic and technological ceilings for seven rice-production regions in China based on yield gaps and on a yield trend pattern analysis for the period 1980-2010. The results indicate that 54.9% of the counties sampled experienced yield stagnation since the 1980. The potential yield ceilings in northern and eastern China decreased to a greater extent than in other regions due to the accompanying climate effects of increases in temperature and decreases in radiation. This may be associated with yield stagnation and halt occurring in approximately 49.8-57.0% of the sampled counties in these areas. South-western China exhibited a promising scope for yield improvement, showing the greatest yield gap (30.6%), whereas the yields were stagnant in 58.4% of the sampled counties. This finding suggests that efforts to overcome the technological ceiling must be given priority so that the available exploitable yield gap can be achieved. North-eastern China, however, represents a noteworthy exception. In the north-central area of this region, climate change has increased the yield potential ceiling, and this increase has been accompanied by the most rapid increase in actual yield: 1.02 ton ha(-1) per decade. Therefore, north-eastern China shows a great potential for rice production, which is favoured by the current climate conditions and available technology level. Additional environmentally friendly economic incentives might be considered in this region. © 2013 John Wiley & Sons Ltd.

  5. Role Overload, Role Self Distance, Role Stagnation as Determinants of Job Satisfaction and Turnover Intention in Banking Sector

    OpenAIRE

    Kunte, Monica; Gupta, Priya; Bhattacharya, Sonali; Neelam, Netra

    2017-01-01

    Purpose: This study examined the relationship of the organizational role stress: Role overload, role self-distance, and role stagnation with job satisfaction and turnover intention with a sample of banking employees in India. Methodology: In this research, we used the RODS scale developed by Prohit and Pareek (2010) for measuring occupational role scale. The reliability of the scale came out to be 0.71. Findings: The majority of employees of all ranks, in both private and public sector banks,...

  6. [Expressions of neurotransmitters in patients of insomnia differentiated as liver stagnation transforming into fire treated with acupuncture].

    Science.gov (United States)

    Ji, Xiangdong; Wang, Qunsong; Zhu, Wenxian

    2015-06-01

    To compare the difference in the efficacy between acupuncture and oral administration of trazodone and the expressions of neurotransmitters in patients of insomnia differentiated as liver stagnation transforming into fire. Seventy patients of insomnia differentiated as liver stagnation transforming into fire were randomized into an observation group and a control group, 35 cases in each one. In the observation group, acupuncture therapy was adopted at Shenmen (HT 7), Baihui (GV 20), Yintang (GV 29), Hegu (LI 4), Taichong (LR 3), etc. The needles were retained for 20 min each time. The treatment was given once a day, the treatment of 2 weeks made one session. In the control group, trazodone, 100 mg, oral administration, once a day, the treatment of 2 weeks made one session. Two sessions were required in the two groups. The scores in Pittsburgh sleep quality index (PSQI) and Asberg rating scale for side effects (SERS), the levels of neurotransmitters such as 5-hydroxy tryptamine (5-HT) and norepinephrine (NE) and the expressions of protein kinase C (PKC) and brain-derived neurotrophic factor (BDNF) in peripheral blood were observed before and after treatment in the two groups. PSQI score and SERS score after treatment were all decreased compared with those in both groups before treatment (both Pinsomnia differentiated as liver stagnation transforming into fire, and reduces serum NE level and increases 5-HT content and BDNF expression, which achieves the better efficacy as compared with the oral administration of trazodone. It is one of the effective approaches to the treatment of insomnia differentiated as liver stagnation transforming into fire.

  7. Impact of Water Chemistry, Pipe Material and Stagnation on the Building Plumbing Microbiome.

    Directory of Open Access Journals (Sweden)

    Pan Ji

    Full Text Available A unique microbiome establishes in the portion of the potable water distribution system within homes and other buildings (i.e., building plumbing. To examine its composition and the factors that shape it, standardized cold water plumbing rigs were deployed at the treatment plant and in the distribution system of five water utilities across the U.S. Three pipe materials (copper with lead solder, CPVC with brass fittings or copper/lead combined pipe were compared, with 8 hour flush cycles of 10 minutes to simulate typical daily use patterns. High throughput Illumina sequencing of 16S rRNA gene amplicons was employed to profile and compare the resident bulk water bacteria and archaea. The utility, location of the pipe rig, pipe material and stagnation all had a significant influence on the plumbing microbiome composition, but the utility source water and treatment practices were dominant factors. Examination of 21 water chemistry parameters suggested that the total chlorine concentration, pH, P, SO42- and Mg were associated with the most of the variation in bulk water microbiome composition. Disinfectant type exerted a notably low-magnitude impact on microbiome composition. At two utilities using the same source water, slight differences in treatment approaches were associated with differences in rare taxa in samples. For genera containing opportunistic pathogens, Utility C samples (highest pH of 9-10 had the highest frequency of detection for Legionella spp. and lowest relative abundance of Mycobacterium spp. Data were examined across utilities to identify a true universal core, special core, and peripheral organisms to deepen insight into the physical and chemical factors that shape the building plumbing microbiome.

  8. Constraining the timescale of magma stagnation beneath Mauna Kea volcano, Hawaii,using diffusion profiles in olivine phenocrysts

    Science.gov (United States)

    Bloch, E. M.; Ganguly, J.

    2009-12-01

    Fe-Mg diffusion profiles have been measured in olivine xenocrysts within alkalic basalts in order to constrain the timescales of magma stagnation beneath Mauna Kea volcano, Hawaii. It has been suggested that during the main tholeiitic shield-building stage, and postshield eruptive stages of Mauna Kea, magmas were stalled and stagnated near the Moho, at a depth of ~15 km. Evidence in support of this hypothesis comes from cumulates formed by gravity-settling and in situ crystallization within magma chambers (Fodor and Galar, 1997), and from clinopyroxene-wholerock thermobarometry on Hamakua basalts (Putirka, in press). The cumulates represent a ‘fossil’ magma chamber which formed primarily from tholeiitic basalts; during the later capping-lava stage of Mauna Kea, alkalic basalts tore off chunks of these cumulates during ascent to the surface. We have measured several diffusion profiles in olivine xenocrysts from a single basalt sample. Because these xenocrysts have homogenous core compositions identical to a neighboring dunite cumulate, and because they are much larger and texturally distinct from compositionally dissimilar olivine phenocrysts, they are interpreted to be cumulate olivines which were dislodged during magma recharge/mixing in the stagnation zone. Although the orientations of the phenocrysts are not yet known, the diffusion profiles have been fit using diffusion coefficients parallel to the c and a crystallographic axes (i.e. minimum and maximum values). Modeling diffusion profiles yields ∫Ddt ≤4.5 x 10-5 cm2. Assuming that the xenocrysts were broken off from the cumulate immediately when the magma chamber was recharged, it is possible to calculate the maximum stagnation time of the basalts. Thus, the retrieved ∫Ddt value yields a maximum stagnation time of ~0.7 years. References: Fodor RV, Galar, PA (1997). A View into the Subsurface of Mauna Kea Volcano, Hawaii: Crystallization Processes Interpreted through the Petrology and Petrography of

  9. Streamline processing of discrete nuclear spectra by means of authoregularized iteration process (the KOLOBOK code)

    International Nuclear Information System (INIS)

    Gadzhokov, V.; Penev, I.; Aleksandrov, L.

    1979-01-01

    A brief description of the KOLOBOK computer code designed for streamline processing of discrete nuclear spectra with symmetric Gaussian shape of the single line on computers of the ES series, models 1020 and above, is given. The program solves the stream of discrete-spectrometry generated nonlinear problems by means of authoregularized iteration process. The Fortran-4 text of the code is reported in an Appendix

  10. InterviewStreamliner, a minimalist, free, open source, relational approach to computer-assisted qualitative data analysis software

    NARCIS (Netherlands)

    H.D. Pruijt (Hans)

    2010-01-01

    textabstractInterviewStreamliner is a free, open source, minimalist alternative to complex computer-assisted qualitative data analysis packages. It builds on the flexibility of relational database management technology.

  11. Brownfields Assessing Contractor Capabilities for Streamlined Site Investigation: Additional Information Regarding All Appropriate Inquiries and Hiring an Environmental Professional

    Science.gov (United States)

    This document assists Brownfields grantees and other decision makers as they assess the capabilities of contractors and consultants to determine their qualifications to provide streamlined and innovative strategies for the assessment and and cleanup.

  12. Report: Follow-Up Report: EPA Proposes to Streamline the Review, Management and Disposal of Hazardous Waste Pharmaceuticals

    Science.gov (United States)

    Report #15-P-0260, August 19, 2015. EPA states that it intends to issue a proposed rule, Management Standards for Hazardous Waste, which will attempt to streamline the approach to managing and disposing of hazardous and nonhazardous pharmaceutical waste.

  13. Guessing right for the next war: streamlining, pooling, and right-timing force design decisions for an environment of uncertainty

    Science.gov (United States)

    2017-05-25

    key ingredients for not only how the Army fought World War II, but also how it continues to organize today. In essence , streamlining pares down every...Germans.1 The Battle of Mortain reflected the US Army in World War II at its best.2 It defined US Army success in the European theater of operations...continues to organize today.5 In essence , streamlining pared down every unit to its essentials based around a critical capability it provided to

  14. Combustion and Mixing Studies in Compressible Flows.

    Science.gov (United States)

    1996-09-01

    Astronautics 2 FULLER ET AL. dence times. It is a primary concern in hypersonic aircraft In fact, studies conducted by Povinelli et al.1 3 and Schetz...downstream. It was reasoned that pressure gradients in the swirling flow. Povinelli et al." such behavior should lead to increased turbulence levels...E.M., "Design and Calibration of Stagnation Tem- tion, 1968, pp. 1153-1162.11 .perature Probes for Use at High Supersonic Speeds and Elevated Povinelli

  15. Predictive Flow Control to Minimize Convective Time Delays

    Science.gov (United States)

    2013-08-19

    external flows around air vehicles or ground based systems such as bridges and buildings, internal flows in pipes and propulsion systems, acoustical...3437, 1977. [4] Bridges , D. H., "The Asymmetric Vortex Wake Problem - Asking the Right Question," A/AA Paper 2006-3553, 2006. [5) Deng, X. Y., Tian, W...Aircraft, Vol. 42, No. 2, 2003, pp. 42~23. [8] Darden, L. and Komerath, N., "Forebody Vortex Control at High Incidence using a Moveable Nose Stagnation

  16. Stable–streamlined and helical cavities following the impact of Leidenfrost spheres

    KAUST Repository

    Mansoor, Mohammad M.

    2017-06-23

    We report results from an experimental study on the formation of stable–streamlined and helical cavity wakes following the free-surface impact of Leidenfrost spheres. Similar to the observations of Mansoor et al. (J. Fluid Mech., vol. 743, 2014, pp. 295–326), we show that acoustic ripples form along the interface of elongated cavities entrained in the presence of wall effects as soon as the primary cavity pinch-off takes place. The crests of these ripples can act as favourable points for closure, producing multiple acoustic pinch-offs, which are found to occur in an acoustic pinch-off cascade. We show that these ripples pacify with time in the absence of physical contact between the sphere and the liquid, leading to extremely smooth cavity wake profiles. More importantly, the downward-facing jet at the apex of the cavity is continually suppressed due to a skin-friction drag effect at the colliding cavity-wall junction, which ultimately produces a stable–streamlined cavity wake. This streamlined configuration is found to experience drag coefficients an order of a magnitude lower than those acting on room-temperature spheres. A striking observation is the formation of helical cavities which occur for impact Reynolds numbers and are characterized by multiple interfacial ridges, stemming from and rotating synchronously about an evident contact line around the sphere equator. The contact line is shown to result from the degeneration of Kelvin–Helmholtz billows into turbulence which are observed forming along the liquid–vapour interface around the bottom hemisphere of the sphere. Using sphere trajectory measurements, we show that this helical cavity wake configuration has 40 %–55 % smaller force coefficients than those obtained in the formation of stable cavity wakes.

  17. Stable–streamlined and helical cavities following the impact of Leidenfrost spheres

    KAUST Repository

    Mansoor, Mohammad M.; Vakarelski, Ivan Uriev; Marston, J. O.; Truscott, T. T.; Thoroddsen, Sigurdur T

    2017-01-01

    We report results from an experimental study on the formation of stable–streamlined and helical cavity wakes following the free-surface impact of Leidenfrost spheres. Similar to the observations of Mansoor et al. (J. Fluid Mech., vol. 743, 2014, pp. 295–326), we show that acoustic ripples form along the interface of elongated cavities entrained in the presence of wall effects as soon as the primary cavity pinch-off takes place. The crests of these ripples can act as favourable points for closure, producing multiple acoustic pinch-offs, which are found to occur in an acoustic pinch-off cascade. We show that these ripples pacify with time in the absence of physical contact between the sphere and the liquid, leading to extremely smooth cavity wake profiles. More importantly, the downward-facing jet at the apex of the cavity is continually suppressed due to a skin-friction drag effect at the colliding cavity-wall junction, which ultimately produces a stable–streamlined cavity wake. This streamlined configuration is found to experience drag coefficients an order of a magnitude lower than those acting on room-temperature spheres. A striking observation is the formation of helical cavities which occur for impact Reynolds numbers and are characterized by multiple interfacial ridges, stemming from and rotating synchronously about an evident contact line around the sphere equator. The contact line is shown to result from the degeneration of Kelvin–Helmholtz billows into turbulence which are observed forming along the liquid–vapour interface around the bottom hemisphere of the sphere. Using sphere trajectory measurements, we show that this helical cavity wake configuration has 40 %–55 % smaller force coefficients than those obtained in the formation of stable cavity wakes.

  18. Novel diffusion tensor imaging technique reveals developmental streamline volume changes in the corticospinal tract associated with leg motor control.

    Science.gov (United States)

    Kamson, David O; Juhász, Csaba; Chugani, Harry T; Jeong, Jeong-Won

    2015-04-01

    Diffusion tensor imaging (DTI) has expanded our knowledge of corticospinal tract (CST) anatomy and development. However, previous developmental DTI studies assessed the CST as a whole, overlooking potential differences in development of its components related to control of the upper and lower extremities. The present cross-sectional study investigated age-related changes, side and gender differences in streamline volume of the leg- and hand-related segments of the CST in children. DTI data of 31 children (1-14 years; mean age: 6±4 years; 17 girls) with normal conventional MRI were analyzed. Leg- and hand-related CST streamline volumes were quantified separately, using a recently validated novel tractography approach. CST streamline volumes on both sides were compared between genders and correlated with age. Higher absolute streamline volumes were found in the left leg-related CST compared to the right (p=0.001) without a gender effect (p=0.4), whereas no differences were found in the absolute hand-related CST volumes (p>0.4). CST leg-related streamline volumes, normalized to hemispheric white matter volumes, declined with age in the right hemisphere only (R=-.51; p=0.004). Absolute leg-related CST streamline volumes showed similar, but slightly weaker correlations. Hand-related absolute or normalized CST streamline volumes showed no age-related variations on either side. These results suggest differential development of CST segments controlling hand vs. leg movements. Asymmetric volume changes in the lower limb motor pathway may be secondary to gradually strengthening left hemispheric dominance and is consistent with previous data suggesting that footedness is a better predictor of hemispheric lateralization than handedness. Copyright © 2014 The Japanese Society of Child Neurology. Published by Elsevier B.V. All rights reserved.

  19. An experimental study on the influence of water stagnation and temperature change on water quality in a full-scale domestic drinking water system.

    Science.gov (United States)

    Zlatanović, Lj; van der Hoek, J P; Vreeburg, J H G

    2017-10-15

    The drinking water quality changes during the transport through distribution systems. Domestic drinking water systems (DDWSs), which include the plumbing between the water meter and consumer's taps, are the most critical points in which water quality may be affected. In distribution networks, the drinking water temperature and water residence time are regarded as indicators of the drinking water quality. This paper describes an experimental research on the influence of stagnation time and temperature change on drinking water quality in a full-scale DDWS. Two sets of stagnation experiments, during winter and summer months, with various stagnation intervals (up to 168 h of stagnation) were carried out. Water and biofilms were sampled at two different taps, a kitchen and a shower tap. Results from this study indicate that temperature and water stagnation affect both chemical and microbial quality in DDWSs, whereas microbial parameters in stagnant water appear to be driven by the temperature of fresh water. Biofilm formed in the shower pipe contained more total and intact cells than the kitchen pipe biofilm. Alphaproteobacteria were found to dominate in the shower biofilm (78% of all Proteobacteria), while in the kitchen tap biofilm Alphaproteobacteria, Betaproteobacteria and Gammaproteobacteria were evenly distributed. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

  20. Role Overload, Role Self Distance, Role Stagnation as Determinants of Job Satisfaction and Turnover Intention in Banking Sector

    Science.gov (United States)

    Kunte, Monica; Gupta, Priya; Bhattacharya, Sonali; Neelam, Netra

    2017-01-01

    Purpose: This study examined the relationship of the organizational role stress: Role overload, role self-distance, and role stagnation with job satisfaction and turnover intention with a sample of banking employees in India. Methodology: In this research, we used the RODS scale developed by Prohit and Pareek (2010) for measuring occupational role scale. The reliability of the scale came out to be 0.71. Findings: The majority of employees of all ranks, in both private and public sector banks, suffer from high role stress of all types. It was found that role overload and role stagnation are inversely associated with banking employees' job satisfaction. Private sector bank employees have more role stress and more unsatisfied than employees of public sector banks. Employees Turnover intention was found to be positively impacted by job satisfaction, contrary to many other studies. Possible reasons have been suggested. Job satisfaction was found to play a partial mediating role in the relationship between role overload and turnover intention with 40% mediation. Further, employees with longer tenure (work experience) have less role stress and are more satisfied. Originality: This study is unique in the sense there is hardly any study linking role stress to job satisfaction and turnover intention, specially in Indian context. PMID:29200554

  1. Role Overload, Role Self Distance, Role Stagnation as Determinants of Job Satisfaction and Turnover Intention in Banking Sector.

    Science.gov (United States)

    Kunte, Monica; Gupta, Priya; Bhattacharya, Sonali; Neelam, Netra

    2017-01-01

    This study examined the relationship of the organizational role stress: Role overload, role self-distance, and role stagnation with job satisfaction and turnover intention with a sample of banking employees in India. In this research, we used the RODS scale developed by Prohit and Pareek (2010) for measuring occupational role scale. The reliability of the scale came out to be 0.71. The majority of employees of all ranks, in both private and public sector banks, suffer from high role stress of all types. It was found that role overload and role stagnation are inversely associated with banking employees' job satisfaction. Private sector bank employees have more role stress and more unsatisfied than employees of public sector banks. Employees Turnover intention was found to be positively impacted by job satisfaction, contrary to many other studies. Possible reasons have been suggested. Job satisfaction was found to play a partial mediating role in the relationship between role overload and turnover intention with 40% mediation. Further, employees with longer tenure (work experience) have less role stress and are more satisfied. This study is unique in the sense there is hardly any study linking role stress to job satisfaction and turnover intention, specially in Indian context.

  2. Standard Practice for Exposure of Solar Collector Cover Materials to Natural Weathering Under Conditions Simulating Stagnation Mode

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    1992-01-01

    1.1 This practice covers a procedure for the exposure of solar collector cover materials to the natural weather environment at elevated temperatures that approximate stagnation conditions in solar collectors having a combined back and edge loss coefficient of less than 1.5 W/(m2 · °C). 1.2 This practice is suitable for exposure of both glass and plastic solar collector cover materials. Provisions are made for exposure of single and double cover assemblies to accommodate the need for exposure of both inner and outer solar collector cover materials. 1.3 This practice does not apply to cover materials for evacuated collectors, photovoltaic cells, flat-plate collectors having a combined back and edge loss coefficient greater than 1.5 W/(m2 ·° C), or flat-plate collectors whose design incorporates means for limiting temperatures during stagnation. 1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard t...

  3. Dye visualization near a three-dimensional stagnation point: application to the vortex breakdown bubble

    DEFF Research Database (Denmark)

    Brøns, Morten; Thompson, M. C.; Hourigan, K.

    2009-01-01

    flows are typically visualized. Predictions based on the model are made for the steady vortex breakdown bubble in a torsionally driven cylinder and compared with computational fluid dynamics predictions and experimental observations. Previous experimental observations using tracer visualization...... techniques have suggested that even for low-Reynolds-number flows, the steady vortex breakdown bubble in a torsionally driven cylinder is not axisymmetric and has an inflow/outflow asymmetry at its tail. Recent numerical and theoretical studies show that the asymmetry of the vortex breakdown bubble......, and consequently its open nature, can be explained by the very small imperfections that are present in any experimental rig. Distinct from this, here it is shown that even for a perfectly axisymmetric flow and breakdown bubble, the combined effect of dye diffusion and the inevitable small errors in the dye...

  4. Streamlining the process: A strategy for making NEPA work better and cost less

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, R.P.; Hansen, J.D. [Hansen Environmental Consultants, Englewood, CO (United States); Wolff, T.A. [Sandia National Labs., Albuquerque, NM (United States)

    1998-05-01

    When the National Environmental Policy Act (NEPA) was enacted in 1969, neither Congress nor the Federal Agencies affected anticipated that implementation of the NEPA process would result in the intolerable delays, inefficiencies, duplication of effort, commitments of excessive financial and personnel resources, and bureaucratic gridlock that have become institutionalized. The 1975 Council on Environmental Quality (CEQ) regulations, which were intended to make the NEPA process more efficient and more useful to decision makers and the public, have either been largely ignored or unintentionally subverted. Agency policy mandates, like those of former Secretary of Energy Hazel R. O`Leary, to ``make NEPA work better and cost less`` have, so far, been disappointingly ineffectual. Federal Agencies have reached the point where almost every constituent of the NEPA process must be subjected to crisis management. This paper focuses on a ten-point strategy for streamlining the NEPA process in order to achieve the Act`s objectives while easing the considerable burden on agencies, the public, and the judicial system. How the ten points are timed and implemented is critical to any successful streamlining.

  5. A new method for calculating volumetric sweeps efficiency using streamline simulation concepts

    International Nuclear Information System (INIS)

    Hidrobo, E A

    2000-01-01

    One of the purposes of reservoir engineering is to quantify the volumetric sweep efficiency for optimizing reservoir management decisions. The estimation of this parameter has always been a difficult task. Until now, sweep efficiency correlations and calculations have been limited to mostly homogeneous 2-D cases. Calculating volumetric sweep efficiency in a 3-D heterogeneous reservoir becomes difficult due to inherent complexity of multiple layers and arbitrary well configurations. In this paper, a new method for computing volumetric sweep efficiency for any arbitrary heterogeneity and well configuration is presented. The proposed method is based on Datta-Gupta and King's formulation of streamline time-of-flight (1995). Given the fact that the time-of-flight reflects the fluid front propagation at various times, then the connectivity in the time-of-flight represents a direct measure of the volumetric sweep efficiency. The proposed approach has been applied to synthetic as well as field examples. Synthetic examples are used to validate the volumetric sweep efficiency calculations using the streamline time-of-flight connectivity criterion by comparison with analytic solutions and published correlations. The field example, which illustrates the feasibility of the approach for large-scale field applications, is from the north Robertson unit, a low permeability carbonate reservoir in west Texas

  6. Craft-Joule Project: Stagnation proof transparently insulated flat plate solar collector (static)

    Energy Technology Data Exchange (ETDEWEB)

    Oliva, A; Cadafalch, J; Perez-Segarra, C.D. [Universitat Politecnica de Catalunya, Barcelona (Spain)] (and others)

    2000-07-01

    The STATIC (STAgnation proof Transparently Insulated flat plate Solar Collector) project is a Craft-Joule Project within the framework of the Non Nuclear Energy Programme Joule III coordinated by the Centre Technologic de Transferencia de Calor (CTTC). The core group of SMEs involved in the project has its main economical activity in the field of solar thermal systems at low temperature level (domestic hot water, solar heating, etc.). Beyond this, a large application potential exists for solar heating at medium temperature level (from 80 to 160 Celsius degrees) : industrial process heat, solar cooling and air conditioning, solar drying , distillation and desalination. Three of the four SME proposers are located in Southern Europe and in the Caribean, where a continuos increase of the demand for air conditioning and cooling has been demonstrated in the last years. The recent development of flat plate solar collectors with honeycomb-type transparent insulation cover has shown that this type of collectors can become a low cost alternative to evacuated tube and high concentrating CPC collectors in the medium temperature range from 80 to 160 Celsius degrees. With the expected reduction of collector cost, that forms 30%-50% of total system cost, a decisive break-through of solar thermal systems using heat in the medium temperature range can be achieved. The feasibility and good performance of these solar collectors has been proved in several prototypes. Nevertheless, up to now no commercial products are available. In order to reach this, the following developments of new concepts are necessary and are being carried out within this project: solution of the problem of overheating: development of collector versions for different working temperatures: optimization of the design with the support of high level numerical simulation. Several prototypes of the new solar collectors are being tested. System tests will also be carried or for two test arrays of optimized collector

  7. Self-Generated Magnetic Fields in the Stagnation Phase of Indirect-Drive Implosions on the National Ignition Facility

    Science.gov (United States)

    Walsh, C. A.; Chittenden, J. P.; McGlinchey, K.; Niasse, N. P. L.; Appelbe, B. D.

    2017-04-01

    Three-dimensional extended-magnetohydrodynamic simulations of the stagnation phase of inertial confinement fusion implosion experiments at the National Ignition Facility are presented, showing self-generated magnetic fields over 104 T . Angular high mode-number perturbations develop large magnetic fields, but are localized to the cold, dense hot-spot surface, which is hard to magnetize. When low-mode perturbations are also present, the magnetic fields are injected into the hot core, reaching significant magnetizations, with peak local thermal conductivity reductions greater than 90%. However, Righi-Leduc heat transport effectively cools the hot spot and lowers the neutron spectra-inferred ion temperatures compared to the unmagnetized case. The Nernst effect qualitatively changes the results by demagnetizing the hot-spot core, while increasing magnetizations at the edge and near regions of large heat loss.

  8. A vortex ring interacting with a vortex filament and its deformation near the two-dimensional stagnation point

    International Nuclear Information System (INIS)

    Kiya, M.; Sato, T.

    1986-01-01

    In this paper the interaction between vortex filaments and vortex rings and the deformation of vortex rings near the two-dimensional stagnation point are simulated by a three-dimensional vortex method. The two problems are respectively concerned with the effect of free-stream turbulence on turbulent plane mixing layers and the production of turbulence by the vortex stretching near saddles associated with large-scale coherent structures. The authors assume that the first step to understand the free-stream turbulence effect is to study the interaction between a vortex ring and a vortex filament and that the process of deformation of a vortex ring gives us a clue to understand physical processes occurring near the saddles

  9. Tables of homogeneous equilibrium critical flow parameters for water in SI units

    International Nuclear Information System (INIS)

    Hall, D.G.; Czapary, L.S.

    1980-09-01

    This reference document presents tables and charts containing data calculated using the homogeneous equilibrium critical flow model (HEM). The ranges of stagnation state properties for which data are presented include: pressures from 2 to 22 120kPa, temperatures from 290 to 640 K, and thermodynamic qualities from 0 to 1

  10. The streamline upwind Petrov-Galerkin stabilising method for the numerical solution of highly advective problems

    Directory of Open Access Journals (Sweden)

    Carlos Humberto Galeano Urueña

    2009-05-01

    Full Text Available This article describes the streamline upwind Petrov-Galerkin (SUPG method as being a stabilisation technique for resolving the diffusion-advection-reaction equation by finite elements. The first part of this article has a short analysis of the importance of this type of differential equation in modelling physical phenomena in multiple fields. A one-dimensional description of the SUPG me- thod is then given to extend this basis to two and three dimensions. The outcome of a strongly advective and a high numerical complexity experiment is presented. The results show how the version of the implemented SUPG technique allowed stabilised approaches in space, even for high Peclet numbers. Additional graphs of the numerical experiments presented here can be downloaded from www.gnum.unal.edu.co.

  11. Streamlining and Standardizing Due Diligence to Ensure Quality of PV Power Plants

    Energy Technology Data Exchange (ETDEWEB)

    Kurtz, Sarah [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2017-11-28

    Those investing in PV power plants would like to have confidence that the plants will provide the anticipated return on investment. While due diligence is capably performed by independent engineers today, as PV systems mature, there will be benefit in standardization and streamlining of this process. The IECRE has defined technical information that is needed as a basis for each transaction step such as approving a design to begin construction, documenting readiness to operate, quantifying performance after a year of operation, and assessing the health of the plant in preparation for sale of the plant. The technical requirements have been defined by IEC Technical Committee 82 and have been designed to be both effective and efficient in completing the assessments. This workshop will describe these new tools that are now available to the community and will include a panel/audience discussion about how and when they can be most effectively used.

  12. Roof Box Shape Streamline Adaptation and the Impact towards Fuel Consumption

    Directory of Open Access Journals (Sweden)

    Abdul Latif M.F.

    2017-01-01

    Full Text Available The fuel price hike is currently a sensational national issue in Malaysia. Since the rationalization of fuel subsidies many were affected especially the middle income family. Vehicle aerodynamic were directly related to the fuel consumption, were extra frontal area result a higher drag force hence higher fuel consumption. Roof box were among the largest contributor to the extra drag, thus the roof box shape rationalization were prominent to reduce the extra drag. The idea of adopting water drop shape to the roof box design shows prominent result. The roof box has been simulated using MIRA virtual wind tunnel modelling via commercial computational fluid dynamic (CFD package. This streamline shape drastically reduce the drag force by 34% resulting to a 1.7% fuel saving compare to the conventional boxy roof box. This is an effort to reduce the carbon foot print for a sustainable green world.

  13. Easy XMM-Newton Data Analysis with the Streamlined ABC Guide!

    Science.gov (United States)

    Valencic, Lynne A.; Snowden, Steven L.; Pence, William D.

    2016-01-01

    The US XMM-Newton GOF has streamlined the time-honored XMM-Newton ABC Guide, making it easier to find and use what users may need to analyze their data. It takes into account what type of data a user might have, if they want to reduce the data on their own machine or over the internet with Web Hera, and if they prefer to use the command window or a GUI. The GOF has also included an introduction to analyzing EPIC and RGS spectra, and PN Timing mode data. The guide is provided for free to students, educators, and researchers for educational and research purposes. Try it out at: http://heasarc.gsfc.nasa.gov/docs/xmm/sl/intro.html

  14. Investigating the effects of streamline-based fiber tractography on matrix scaling in brain connective network.

    Science.gov (United States)

    Jan, Hengtai; Chao, Yi-Ping; Cho, Kuan-Hung; Kuo, Li-Wei

    2013-01-01

    Investigating the brain connective network using the modern graph theory has been widely applied in cognitive and clinical neuroscience research. In this study, we aimed to investigate the effects of streamline-based fiber tractography on the change of network properties and established a systematic framework to understand how an adequate network matrix scaling can be determined. The network properties, including degree, efficiency and betweenness centrality, show similar tendency in both left and right hemispheres. By employing the curve-fitting process with exponential law and measuring the residuals, the association between changes of network properties and threshold of track numbers is found and an adequate range of investigating the lateralization of brain network is suggested. The proposed approach can be further applied in clinical applications to improve the diagnostic sensitivity using network analysis with graph theory.

  15. An analytical study on groundwater flow in drainage basins with horizontal wells

    Science.gov (United States)

    Wang, Jun-Zhi; Jiang, Xiao-Wei; Wan, Li; Wang, Xu-Sheng; Li, Hailong

    2014-06-01

    Analytical studies on release/capture zones are often limited to a uniform background groundwater flow. In fact, for basin-scale problems, the undulating water table would lead to the development of hierarchically nested flow systems, which are more complex than a uniform flow. Under the premise that the water table is a replica of undulating topography and hardly influenced by wells, an analytical solution of hydraulic head is derived for a two-dimensional cross section of a drainage basin with horizontal injection/pumping wells. Based on the analytical solution, distributions of hydraulic head, stagnation points and flow systems (including release/capture zones) are explored. The superposition of injection/pumping wells onto the background flow field leads to the development of new internal stagnation points and new flow systems (including release/capture zones). Generally speaking, the existence of n injection/pumping wells would result in up to n new internal stagnation points and up to 2n new flow systems (including release/capture zones). The analytical study presented, which integrates traditional well hydraulics with the theory of regional groundwater flow, is useful in understanding basin-scale groundwater flow influenced by human activities.

  16. Psychological distress and streamlined BreastScreen follow-up assessment versus standard assessment.

    Science.gov (United States)

    Sherman, Kerry A; Winch, Caleb J; Borecky, Natacha; Boyages, John

    2013-11-04

    To establish whether altered protocol characteristics of streamlined StepDown breast assessment clinics heightened or reduced the psychological distress of women in attendance compared with standard assessment. Willingness to attend future screening was also compared between the assessment groups. Observational, prospective study of women attending either a mammogram-only StepDown or a standard breast assessment clinic. Women completed questionnaires on the day of assessment and 1 month later. Women attending StepDown (136 women) or standard assessment clinics (148 women) at a BreastScreen centre between 10 November 2009 and 7 August 2010. Breast cancer worries; positive and negative psychological consequences of assessment (Psychological Consequences Questionnaire); breast cancer-related intrusion and avoidance (Impact of Event Scale); and willingness to attend, and uneasiness about, future screening. At 1-month follow-up, no group differences were evident between those attending standard and StepDown clinics on breast cancer worries (P= 0.44), positive (P= 0.88) and negative (P = 0.65) consequences, intrusion (P = 0.64), and avoidance (P = 0.87). Willingness to return for future mammograms was high, and did not differ between groups (P = 0.16), although higher levels of unease were associated with lessened willingness to rescreen (P = 0.04). There was no evidence that attending streamlined StepDown assessments had different outcomes in terms of distress than attending standard assessment clinics for women with a BreastScreen-detected abnormality. However, unease about attending future screening was generally associated with less willingness to do so in both groups; thus, there is a role for psycho-educational intervention to address these concerns.

  17. Flow Curvature Effects for VAWT: a Review of Virtual Airfoil Transformations and Implementation in XFOIL

    DEFF Research Database (Denmark)

    van der Horst, Sander; van de Wiel, Jelmer E.; Ferreira, Carlos Simao

    2016-01-01

    Blades on a Vertical Axis Wind Turbine (VAWT) experience curved streamlines, caused by the rotation of the turbine. This phenomenon is known as flow curvature and has effects on the aerodynamic loading of the blades. Several authors have proposed methods to account for flow curvature, resulting...

  18. Proposed Model for a Streamlined, Cohesive, and Optimized K-12 STEM Curriculum with a Focus on Engineering

    Science.gov (United States)

    Locke, Edward

    2009-01-01

    This article presents a proposed model for a clear description of K-12 age-possible engineering knowledge content, in terms of the selection of analytic principles and predictive skills for various grades, based on the mastery of mathematics and science pre-requisites, as mandated by national or state performance standards; and a streamlined,…

  19. Topology of helical fluid flow

    DEFF Research Database (Denmark)

    Andersen, Morten; Brøns, Morten

    2014-01-01

    function for the topology of the streamline pattern in incompressible flows. On this basis, we perform a comprehensive study of the topology of the flow field generated by a helical vortex filament in an ideal fluid. The classical expression for the stream function obtained by Hardin (Hardin, J. C. 1982...... the zeroes of a single real function of one variable, and we show that three different flow topologies can occur, depending on a single dimensionless parameter. By including the self-induced velocity on the vortex filament by a localised induction approximation, the stream function is slightly modified...... and an extra parameter is introduced. In this setting two new flow topologies arise, but not more than two critical points occur for any combination of parameters....

  20. Upscaling of Forchheimer flows

    KAUST Repository

    Aulisa, Eugenio

    2014-08-01

    In this work we propose upscaling method for nonlinear Forchheimer flow in heterogeneous porous media. The generalized Forchheimer law is considered for incompressible and slightly-compressible single-phase flows. We use recently developed analytical results (Aulisa et al., 2009) [1] and formulate the resulting system in terms of a degenerate nonlinear flow equation for the pressure with the nonlinearity depending on the pressure gradient. The coarse scale parameters for the steady state problem are determined so that the volumetric average of velocity of the flow in the domain on fine scale and on coarse scale are close. A flow-based coarsening approach is used, where the equivalent permeability tensor is first evaluated following streamline methods for linear cases, and modified in order to take into account the nonlinear effects. Compared to previous works (Garibotti and Peszynska, 2009) [2], (Durlofsky and Karimi-Fard) [3], this approach can be combined with rigorous mathematical upscaling theory for monotone operators, (Efendiev et al., 2004) [4], using our recent theoretical results (Aulisa et al., 2009) [1]. The developed upscaling algorithm for nonlinear steady state problems is effectively used for variety of heterogeneities in the domain of computation. Direct numerical computations for average velocity and productivity index justify the usage of the coarse scale parameters obtained for the special steady state case in the fully transient problem. For nonlinear case analytical upscaling formulas in stratified domain are obtained. Numerical results were compared to these analytical formulas and proved to be highly accurate. © 2014.

  1. Impedance spectroscopy and structural properties of the perovskite-like Sn(Ba,Sr)O{sub 3} stagnate

    Energy Technology Data Exchange (ETDEWEB)

    Cuervo Farfan, J. [Grupo de Fisica de Nuevos Materiales, Departamento de Fisica, Universidad Nacional de Colombia, AA 5997, Bogota DC (Colombia); Ciencias Basicas, Universidad Manuela Beltran, Bogota DC (Colombia); Olaya, J.J. [Departamento de Ingenieria Mecanica y Mecatronica, Universidad Nacional de Colombia, Bogota DC (Colombia); Vera Lopez, E. [Grupo de Superficies, Electroquimica y Corrosion, Universidad Pedagogica y Tecnologica de Colombia, Tunja (Colombia); Landinez Tellez, D.A. [Grupo de Fisica de Nuevos Materiales, Departamento de Fisica, Universidad Nacional de Colombia, AA 5997, Bogota DC (Colombia); Roa-Rojas, J., E-mail: jroar@unal.edu.co [Grupo de Fisica de Nuevos Materiales, Departamento de Fisica, Universidad Nacional de Colombia, AA 5997, Bogota DC (Colombia)

    2012-08-15

    An exhaustive study of structural, electrical and transport properties on the perovskite stagnate Sn(Ba,Sr)O{sub 3} was performed. Samples of SnBa{sub 1-x}Sr{sub x}O{sub 3} with 0{<=}x{<=}1.00 were prepared by the solid state reaction method. The crystallographic structure was studied by X-ray diffraction experiments and Rietveld refinement using the GSAS code. Results reveal the material synthesized in a cubic structure (space group Pm3-bar m, no. 221) for 0{<=}x{<=}0.50 and in an orthorhombic (space group Pnma, no. 62) for x>0.50. The approximate grain size was found from experiments' Scanning Electron Microscopy. The electric response was studied by the Impedance Spectroscopy technique from 10.0 mHz up to 0,10 MHz. Electric polarization measurements for SnSrO{sub 3} and SnBaO{sub 3} were determined through curves of polarization as a function of applied electric field, which reveal the ferroelectric character of the material. From the saturation polarization the dielectric constants of materials were calculated.

  2. One- and two-dimensional density and temperature measurements of an argon-neon Z-pinch plasma at stagnation

    International Nuclear Information System (INIS)

    Wong, K.L.; Springer, P.T.; Hammer, J.H.; Iglesias, C.A.; Osterheld, A.L.; Foord, M.E.; Bruns, H.C.; Emig, J.A.; Deeney, C.

    1996-10-01

    In order to benchmark and improve current 2D radiation magnetohydrodynamic (MHD) models of Z-pinch plasmas, we have performed experiments which characterize the plasma -conditions at stagnation. In the experiments the SATURN pulsed power facility at Sandia National Laboratory was used to create an imploding -Ar-Ne plasma. An absolutely calibrated, high resolution space- and time- resolving Johann crystal spectrometer was used to infer the electron temperature Te from the slope of the hydrogenlike Ne free-bound continuum, and the ion density ni from the Stark broadening of the Ar heliunlike Rydberg series. 2D electron temperature profiles of the plasma are obtained from a set of imaging crystals also focused on the Ne free-bound continuum. We shot two types of gas nozzles in the experiment, annular and uniform fill which varies the amount of mass in the plasma. 2D local thermodynamic equilibrium (LTE) and non-LTE MM models predict a radiating region denser and cooler than measured

  3. Impedance spectroscopy and structural properties of the perovskite-like Sn(Ba,Sr)O3 stagnate

    International Nuclear Information System (INIS)

    Cuervo Farfán, J.; Olaya, J.J.; Vera López, E.; Landínez Téllez, D.A.; Roa-Rojas, J.

    2012-01-01

    An exhaustive study of structural, electrical and transport properties on the perovskite stagnate Sn(Ba,Sr)O 3 was performed. Samples of SnBa 1-x Sr x O 3 with 0≤x≤1.00 were prepared by the solid state reaction method. The crystallographic structure was studied by X-ray diffraction experiments and Rietveld refinement using the GSAS code. Results reveal the material synthesized in a cubic structure (space group Pm3-bar m, no. 221) for 0≤x≤0.50 and in an orthorhombic (space group Pnma, no. 62) for x>0.50. The approximate grain size was found from experiments' Scanning Electron Microscopy. The electric response was studied by the Impedance Spectroscopy technique from 10.0 mHz up to 0,10 MHz. Electric polarization measurements for SnSrO 3 and SnBaO 3 were determined through curves of polarization as a function of applied electric field, which reveal the ferroelectric character of the material. From the saturation polarization the dielectric constants of materials were calculated.

  4. A Critical Pragmatism: Marcuse, Adorno, and Peirce on the Artificial Stagnation of Individual and Social Development in Advanced Industrial Societies

    Directory of Open Access Journals (Sweden)

    Clancy Smith

    2009-12-01

    Full Text Available This paper will analyze the effects advanced industrial societies have on individual and social development through the eyes of Marcuse’s One-Dimensional Man and the moral consequences of such artificial stagnation through Adorno’s lectures on The Problems of Moral Philosophy. Because such an investigation necessarily brings us into the realm of social psychology, we will turn to the social psychological tradition at the heart of American pragmatism, a target for critical theorists who are often antagonistic to the entire tradition. We will endeavor to advance two alternate readings of the work of C.S. Peirce, arguing that although one type of pragmatism may be justly attacked by critical theorists, there is another, I argue, more critical manifestation of pragmatic human development, that requires the type of autonomy-infused, open-ended development that Marcuse champions. Moreover, I will argue that Peirce’s seminal essay “The Fixation of Belief” anticipated many of Marcuse’s critiques of advanced industrial societies by nearly ninety years.

  5. One- and two-dimensional density and temperature measurements of an argon-neon Z-pinch plasma at stagnation

    International Nuclear Information System (INIS)

    Wong, K.L.; Springer, P.T.; Hammer, J.H.; Iglesias, C.A.; Osterheld, A.L.; Foord, M.E.; Bruns, H.C.; Emig, J.A.; Deeney, C.

    1997-01-01

    In order to benchmark and improve current 2D radiation magnetohydrodynamic (MHD) models of Z-pinch plasmas, we have performed experiments which characterize the plasma conditions at stagnation. In the experiments the SATURN pulsed power facility at Sandia National Laboratory was used to create an imploding Ar-Ne plasma. An absolutely calibrated, high resolution space- and time-resolving Johann crystal spectrometer was used to infer the electron temperature T e from the slope of the hydrogenlike Ne free-bound continuum, and the ion density n i from the Stark broadening of the Ar heliumlike Rydberg series. 2D electron temperature profiles of the plasma are obtained from a set of imaging crystals also focused on the Ne free-bound continuum. We shot two types of gas nozzles in the experiment, annular and uniform fill, which varies the amount of mass in the plasma. 2D local thermodynamic equilibrium (LTE) and non-LTE MHD models predict a radiating region denser and cooler than measured. copyright 1997 American Institute of Physics

  6. Challenges and Obstacles of e-Government Streamlining: A Case Study

    Directory of Open Access Journals (Sweden)

    Anupam K. Nath

    2014-05-01

    Full Text Available e-Government streamlining has been a challenge since its inception in the domain of e-business. Business organizations face challenges while trying to collaborate with partners through the use of information technology in order to ensure efficient delivery of services. One of the major reasons for these inefficient services has been political bureaucracies among government organizations. To meet this challenge, a transparent and networked environment is required where government organizations can effectively partner with other relevant organizations. Using a case study analysis, we intend to identify not just the challenges in government organizations while providing services which require collaborative effort, but also the obstacles in adopting new technology for collaboration. We believe that the outcome of our research could provide a generalized guideline for government agencies where there is need for digital collaboration. Our findings will thus help government organizations to address the challenges in digital collaboration, and also help them implement new technology successfully to ensure efficient delivery of services.

  7. Surrogate Based Optimization of Aerodynamic Noise for Streamlined Shape of High Speed Trains

    Directory of Open Access Journals (Sweden)

    Zhenxu Sun

    2017-02-01

    Full Text Available Aerodynamic noise increases with the sixth power of the running speed. As the speed increases, aerodynamic noise becomes predominant and begins to be the main noise source at a certain high speed. As a result, aerodynamic noise has to be focused on when designing new high-speed trains. In order to perform the aerodynamic noise optimization, the equivalent continuous sound pressure level (SPL has been used in the present paper, which could take all of the far field observation probes into consideration. The Non-Linear Acoustics Solver (NLAS approach has been utilized for acoustic calculation. With the use of Kriging surrogate model, a multi-objective optimization of the streamlined shape of high-speed trains has been performed, which takes the noise level in the far field and the drag of the whole train as the objectives. To efficiently construct the Kriging model, the cross validation approach has been adopted. Optimization results reveal that both the equivalent continuous sound pressure level and the drag of the whole train are reduced in a certain extent.

  8. Localized Plasticity in the Streamlined Genomes of Vinyl Chloride Respiring Dehalococcoides

    Energy Technology Data Exchange (ETDEWEB)

    McMurdie, Paul J.; Behrens, Sebastien F.; Muller, Jochen A.; Goke, Jonathan; Ritalahti, Kirsti M.; Wagner, Ryan; Goltsman, Eugene; Lapidus, Alla; Holmes, Susan; Loffler, Frank E.; Spormann, Alfred M.

    2009-06-30

    Vinyl chloride (VC) is a human carcinogen and widespread priority pollutant. Here we report the first, to our knowledge, complete genome sequences of microorganisms able to respire VC, Dehalococcoides sp. strains VS and BAV1. Notably, the respective VC reductase encoding genes, vcrAB and bvcAB, were found embedded in distinct genomic islands (GEIs) with different predicted integration sites, suggesting that these genes were acquired horizontally and independently by distinct mechanisms. A comparative analysis that included two previously sequenced Dehalococcoides genomes revealed a contextually conserved core that is interrupted by two high plasticity regions (HPRs) near the Ori. These HPRs contain the majority of GEIs and strain-specific genes identified in the four Dehalococcoides genomes, an elevated number of repeated elements including insertion sequences (IS), as well as 91 of 96 rdhAB, genes that putatively encode terminal reductases in organohalide respiration. Only three core rdhA orthologous groups were identified, and only one of these groups is supported by synteny. The low number of core rdhAB, contrasted with the high rdhAB numbers per genome (up to 36 in strain VS), as well as their colocalization with GEIs and other signatures for horizontal transfer, suggests that niche adaptation via organohalide respiration is a fundamental ecological strategy in Dehalococccoides. This adaptation has been exacted through multiple mechanisms of recombination that are mainly confined within HPRs of an otherwise remarkably stable, syntenic, streamlined genome among the smallest of any free-living microorganism.

  9. Symbiotic adaptation drives genome streamlining of the cyanobacterial sponge symbiont "Candidatus Synechococcus pongiarum"

    KAUST Repository

    Gao, Zhao-Ming

    2014-04-01

    "Candidatus Synechococcus spongiarum" is a cyanobacterial symbiont widely distributed in sponges, but its functions at the genome level remain unknown. Here, we obtained the draft genome (1.66 Mbp, 90% estimated genome recovery) of "Ca. Synechococcus spongiarum" strain SH4 inhabiting the Red Sea sponge Carteriospongia foliascens. Phylogenomic analysis revealed a high dissimilarity between SH4 and free-living cyanobacterial strains. Essential functions, such as photosynthesis, the citric acid cycle, and DNA replication, were detected in SH4. Eukaryoticlike domains that play important roles in sponge-symbiont interactions were identified exclusively in the symbiont. However, SH4 could not biosynthesize methionine and polyamines and had lost partial genes encoding low-molecular-weight peptides of the photosynthesis complex, antioxidant enzymes, DNA repair enzymes, and proteins involved in resistance to environmental toxins and in biosynthesis of capsular and extracellular polysaccharides. These genetic modifications imply that "Ca. Synechococcus spongiarum" SH4 represents a low-light-adapted cyanobacterial symbiont and has undergone genome streamlining to adapt to the sponge\\'s mild intercellular environment. 2014 Gao et al.

  10. Streamlining Workflow for Endovascular Mechanical Thrombectomy: Lessons Learned from a Comprehensive Stroke Center.

    Science.gov (United States)

    Wang, Hongjin; Thevathasan, Arthur; Dowling, Richard; Bush, Steven; Mitchell, Peter; Yan, Bernard

    2017-08-01

    Recently, 5 randomized controlled trials confirmed the superiority of endovascular mechanical thrombectomy (EMT) to intravenous thrombolysis in acute ischemic stroke with large-vessel occlusion. The implication is that our health systems would witness an increasing number of patients treated with EMT. However, in-hospital delays, leading to increased time to reperfusion, are associated with poor clinical outcomes. This review outlines the in-hospital workflow of the treatment of acute ischemic stroke at a comprehensive stroke center and the lessons learned in reduction of in-hospital delays. The in-hospital workflow for acute ischemic stroke was described from prehospital notification to femoral arterial puncture in preparation for EMT. Systematic review of literature was also performed with PubMed. The implementation of workflow streamlining could result in reduction of in-hospital time delays for patients who were eligible for EMT. In particular, time-critical measures, including prehospital notification, the transfer of patients from door to computed tomography (CT) room, initiation of intravenous thrombolysis in the CT room, and the mobilization of neurointervention team in parallel with thrombolysis, all contributed to reduction in time delays. We have identified issues resulting in in-hospital time delays and have reported possible solutions to improve workflow efficiencies. We believe that these measures may help stroke centers initiate an EMT service for eligible patients. Copyright © 2017 National Stroke Association. Published by Elsevier Inc. All rights reserved.

  11. Streamlining Appointment, Promotion, and Tenure Procedures to Promote Early-Career Faculty Success.

    Science.gov (United States)

    Smith, Shannon B; Hollerbach, Ann; Donato, Annemarie Sipkes; Edlund, Barbara J; Atz, Teresa; Kelechi, Teresa J

    2016-01-01

    A critical component of the progression of a successful academic career is being promoted in rank. Early-career faculty are required to have an understanding of appointment, promotion, and tenure (APT) guidelines, but many factors often impede this understanding, thwarting a smooth and planned promotion pathway for professional advancement. This article outlines the steps taken by an APT committee to improve the promotion process from instructor to assistant professor. Six sigma's DMAIC improvement model was selected as the guiding operational framework to remove variation in the promotion process. After faculty handbook revisions were made, several checklists developed, and a process review rubric was implemented; recently promoted faculty were surveyed on satisfaction with the process. Faculty opinions captured in the survey suggest increased transparency in the process and perceived support offered by the APT committee. Positive outcomes include a strengthened faculty support framework, streamlined promotion processes, and improved faculty satisfaction. Changes to the APT processes resulted in an unambiguous and standardized pathway for successful promotion. Copyright © 2016 Elsevier Inc. All rights reserved.

  12. Streamlining the Design-to-Build Transition with Build-Optimization Software Tools.

    Science.gov (United States)

    Oberortner, Ernst; Cheng, Jan-Fang; Hillson, Nathan J; Deutsch, Samuel

    2017-03-17

    Scaling-up capabilities for the design, build, and test of synthetic biology constructs holds great promise for the development of new applications in fuels, chemical production, or cellular-behavior engineering. Construct design is an essential component in this process; however, not every designed DNA sequence can be readily manufactured, even using state-of-the-art DNA synthesis methods. Current biological computer-aided design and manufacture tools (bioCAD/CAM) do not adequately consider the limitations of DNA synthesis technologies when generating their outputs. Designed sequences that violate DNA synthesis constraints may require substantial sequence redesign or lead to price-premiums and temporal delays, which adversely impact the efficiency of the DNA manufacturing process. We have developed a suite of build-optimization software tools (BOOST) to streamline the design-build transition in synthetic biology engineering workflows. BOOST incorporates knowledge of DNA synthesis success determinants into the design process to output ready-to-build sequences, preempting the need for sequence redesign. The BOOST web application is available at https://boost.jgi.doe.gov and its Application Program Interfaces (API) enable integration into automated, customized DNA design processes. The herein presented results highlight the effectiveness of BOOST in reducing DNA synthesis costs and timelines.

  13. Comparative Analysis of Wolbachia Genomes Reveals Streamlining and Divergence of Minimalist Two-Component Systems

    Science.gov (United States)

    Christensen, Steen; Serbus, Laura Renee

    2015-01-01

    Two-component regulatory systems are commonly used by bacteria to coordinate intracellular responses with environmental cues. These systems are composed of functional protein pairs consisting of a sensor histidine kinase and cognate response regulator. In contrast to the well-studied Caulobacter crescentus system, which carries dozens of these pairs, the streamlined bacterial endosymbiont Wolbachia pipientis encodes only two pairs: CckA/CtrA and PleC/PleD. Here, we used bioinformatic tools to compare characterized two-component system relays from C. crescentus, the related Anaplasmataceae species Anaplasma phagocytophilum and Ehrlichia chaffeensis, and 12 sequenced Wolbachia strains. We found the core protein pairs and a subset of interacting partners to be highly conserved within Wolbachia and these other Anaplasmataceae. Genes involved in two-component signaling were positioned differently within the various Wolbachia genomes, whereas the local context of each gene was conserved. Unlike Anaplasma and Ehrlichia, Wolbachia two-component genes were more consistently found clustered with metabolic genes. The domain architecture and key functional residues standard for two-component system proteins were well-conserved in Wolbachia, although residues that specify cognate pairing diverged substantially from other Anaplasmataceae. These findings indicate that Wolbachia two-component signaling pairs share considerable functional overlap with other α-proteobacterial systems, whereas their divergence suggests the potential for regulatory differences and cross-talk. PMID:25809075

  14. Symbiotic adaptation drives genome streamlining of the cyanobacterial sponge symbiont "Candidatus Synechococcus pongiarum"

    KAUST Repository

    Gao, Zhao-Ming; Wang, Yong; Tian, Ren-Mao; Wong, Yue Him; Batang, Zenon B.; Al-Suwailem, Abdulaziz M.; Bajic, Vladimir B.; Qian, Pei-Yuan

    2014-01-01

    "Candidatus Synechococcus spongiarum" is a cyanobacterial symbiont widely distributed in sponges, but its functions at the genome level remain unknown. Here, we obtained the draft genome (1.66 Mbp, 90% estimated genome recovery) of "Ca. Synechococcus spongiarum" strain SH4 inhabiting the Red Sea sponge Carteriospongia foliascens. Phylogenomic analysis revealed a high dissimilarity between SH4 and free-living cyanobacterial strains. Essential functions, such as photosynthesis, the citric acid cycle, and DNA replication, were detected in SH4. Eukaryoticlike domains that play important roles in sponge-symbiont interactions were identified exclusively in the symbiont. However, SH4 could not biosynthesize methionine and polyamines and had lost partial genes encoding low-molecular-weight peptides of the photosynthesis complex, antioxidant enzymes, DNA repair enzymes, and proteins involved in resistance to environmental toxins and in biosynthesis of capsular and extracellular polysaccharides. These genetic modifications imply that "Ca. Synechococcus spongiarum" SH4 represents a low-light-adapted cyanobacterial symbiont and has undergone genome streamlining to adapt to the sponge's mild intercellular environment. 2014 Gao et al.

  15. A streamlined DNA tool for global identification of heavily exploited coastal shark species (genus Rhizoprionodon.

    Directory of Open Access Journals (Sweden)

    Danillo Pinhal

    Full Text Available Obtaining accurate species-specific landings data is an essential step toward achieving sustainable shark fisheries. Globally distributed sharpnose sharks (genus Rhizoprionodon exhibit life-history characteristics (rapid growth, early maturity, annual reproduction that suggests that they could be fished in a sustainable manner assuming an investment in monitoring, assessment and careful management. However, obtaining species-specific landings data for sharpnose sharks is problematic because they are morphologically very similar to one another. Moreover, sharpnose sharks may also be confused with other small sharks (either small species or juveniles of large species once they are processed (i.e., the head and fins are removed. Here we present a highly streamlined molecular genetics approach based on seven species-specific PCR primers in a multiplex format that can simultaneously discriminate body parts from the seven described sharpnose shark species commonly occurring in coastal fisheries worldwide. The species-specific primers are based on nucleotide sequence differences among species in the nuclear ribosomal internal transcribed spacer 2 locus (ITS2. This approach also distinguishes sharpnose sharks from a wide range of other sharks (52 species and can therefore assist in the regulation of coastal shark fisheries around the world.

  16. [Comparative analysis on the biological basis of blood stasis syndrome induced by qi-stagnation and qi-deficiency in patients with unstable angina pectoris].

    Science.gov (United States)

    Ren, Jian-xun; Liu, Jian-xun; Lin, Cheng-ren

    2010-04-01

    To comparatively analyse the objective characteristics of different syndrome types of qi-disturbance-induced blood stasis syndrome (QDBS) in the pathogenetic evolution of unstable angina coronary heart disease (UA-CHD). Seventy-eight patients with UA-CHD of QDBS were differentiated into 2 groups: 55 in the qi-deficiency-induced blood-stasis syndrome group (A) and 23 in the qi-stagnation-induced blood-stasis syndrome group (B). The comparative analysis on them was carried out through comparing their blood pressure, glucose and lipid metabolisms, coagulation function, thyroid function and inflammation reaction changes, etc. In the pathogenetic process of qi-disturbance induced blood stasis, the initiating age, levels of HbA1c, TSH, PT and APTT between the two groups were significantly different (P emotional stress is possibly the essence of qi-stagnation induced blood stasis syndrome.

  17. Robust Preconditioning Estimates for Convection-Dominated Elliptic Problems via a Streamline Poincaré--Friedrichs Inequality

    Czech Academy of Sciences Publication Activity Database

    Axelsson, Owe; Karátson, J.; Kovács, B.

    2014-01-01

    Roč. 52, č. 6 (2014), s. 2957-2976 ISSN 0036-1429 R&D Projects: GA MŠk ED1.1.00/02.0070 Institutional support: RVO:68145535 Keywords : streamline diffusion finite element method * solving convection-dominated elliptic problems * convergence is robust Subject RIV: BA - General Mathematics Impact factor: 1.788, year: 2014 http://epubs.siam.org/doi/abs/10.1137/130940268

  18. Stagnations of increasing trends in negative pressure with repeated cavitation in water/metal Berthelot tubes as a result of mechanical sealing

    International Nuclear Information System (INIS)

    Hiro, Kazuki; Ohde, Yoshihito; Tanzawa, Yasutoshi

    2003-01-01

    To investigate effects of mechanical sealing on negative pressures in water/metal tube Berthelot systems, trends in negative pressure are observed through runs of temperature cycles below 90 deg. C in two systems made of metals having small amounts of gas inclusions. The first system is a pre-degassed all-stainless-steel tube/plug system. The steel is a special product for vacuum engineering. The second is the same tube sealed with plugs made of silver solidified one-dimensionally in a vacuum furnace. A new type of trend, stagnation for intermediate cycles is found in both systems so long as sealing distortion of each plug is small in amount. The stagnation period for the first system is longer than that for the second one. A metallurgical mechanism of a gas-being-replenished crevice model is proposed: distorted parts of metals undergo heat-treatment during runs of temperature cycles, and the heat-treatment enhances the rates of impurity gas transports to crevices on the metal surface where cavitation occurs, and the transport causes the stagnation for cycles during which the rates are still high

  19. Flow patterns in a cylindrical porous enclosure

    International Nuclear Information System (INIS)

    Sezai, I.

    2005-01-01

    Natural convection in a 3-D vertical cylinder containing an isotropic porous media is studied numerically using the Brinkman and Forcheimer's extensions to the Darcy law. The cylinder is heated from below and cooled from top while the vertical wall is insulated. The formation of multiple flow patterns are investigated by varying the Rayleigh number. Altogether, six different steady flow patterns are found exhibiting different symmetries. The results are presented in terms of projection of streamlines and Nusselt number distributions on the heated plate. (authors)

  20. Flow patterns in a cylindrical porous enclosure

    Energy Technology Data Exchange (ETDEWEB)

    Sezai, I. [Eastern Mediterranean Univ., Dept. Mechanical Engineering(Turkey)

    2005-07-01

    Natural convection in a 3-D vertical cylinder containing an isotropic porous media is studied numerically using the Brinkman and Forcheimer's extensions to the Darcy law. The cylinder is heated from below and cooled from top while the vertical wall is insulated. The formation of multiple flow patterns are investigated by varying the Rayleigh number. Altogether, six different steady flow patterns are found exhibiting different symmetries. The results are presented in terms of projection of streamlines and Nusselt number distributions on the heated plate. (authors)

  1. Improving and streamlining the workflow in the graphic arts and printing industry

    Science.gov (United States)

    Tuijn, Chris

    2003-01-01

    In order to survive in the economy of today, an ever-increasing productivity is required from all the partners participating in a specific business process. This is not different for the printing industry. One of the ways to remain profitable is, on one hand, to reduce costs by automation and aiming for large-scale projects and, on the other hand, to specialize and become an expert in the area in which one is active. One of the ways to realize these goals is by streamlining the communication of the different partners and focus on the core business. If we look at the graphic arts and printing industry, we can identify different important players that eventually help in the realization of printed material. For the printing company (as is the case for any other company), the most important player is the customer. This role can be adopted by many different players including publishers, companies, non-commercial institutions, private persons etc. Sometimes, the customer will be the content provider as well but this is not always the case. Often, the content is provided by other organizations such as design and prepress agencies, advertising companies etc. In most printing organizations, the customer has one contact person often referred to as the CSR (Customers Service Representative). Other people involved at the printing organization include the sales representatives, prepress operators, printing operators, postpress operators, planners, the logistics department, the financial department etc. In the first part of this article, we propose a solution that will improve the communication between all the different actors in the graphic arts and printing industry considerably and will optimize and streamline the overall workflow as well. This solution consists of an environment in which the customer can communicate with the CSR to ask for a quote based on a specific product intent; the CSR will then (after the approval from the customer's side) organize the work and brief

  2. A streamlined risk screening method for managing reutilization of abandoned factories in Taiwan

    Directory of Open Access Journals (Sweden)

    I-Chun Chen

    2017-05-01

    Full Text Available An integrated management strategy that considers the competing relationships between land values and associated risks in the process of land-use conversion is needed to assess and manage the reutilization of brownfields. However, the often large number of individual brownfields renders it difficult to conduct a completed risk assessment for all sites, and a streamlined risk screening method would facilitate prioritization of the redevelopment of those factories. This methodology takes into account the spatial heterogeneity of contaminated lands and produces risk mapping that compiles complex risk-related information. Using abandoned factories in Taiwan as a case study, the method considers 40 points (50% accumulated probability as the threshold of acceptable risk. Emergency risk should be over 90% of accumulated probability. For the sustainability of brownfield reutilization in Taiwan, this research uses a risk matrix to identify the low, middle, and high risk for brownfield reutilization. It can indicate zones with a high risk level or low economic incentive as areas of concern for future decision making. In Taiwan, high-risk sites with high incentive account for only 21.3% of the sites. In contrast, the sites with the lowest incentive and low risk account for 57.6% of the sites. To avoid failure in the brownfield market, three strategies are suggested: (1 flexible land management with urban planning is a feasible option for protecting the receptor's health; (2 the government could provide the tool or brownfield funds to reduce the uncertainty of investment risk; and (3 risk monitoring and management can reduce the possible pitfalls associated with brownfield reutilization.

  3. Providing Data Management Support to NASA Airborne Field Studies through Streamlined Usability Design

    Science.gov (United States)

    Beach, A. L., III; Northup, E. A.; Early, A. B.; Chen, G.

    2016-12-01

    Airborne field studies are an effective way to gain a detailed understanding of atmospheric processes for scientific research on climate change and air quality relevant issues. One major function of airborne project data management is to maintain seamless data access within the science team. This allows individual instrument principal investigators (PIs) to process and validate their own data, which requires analysis of data sets from other PIs (or instruments). The project's web platform streamlines data ingest, distribution processes, and data format validation. In May 2016, the NASA Langley Research Center (LaRC) Atmospheric Science Data Center (ASDC) developed a new data management capability to help support the Korea U.S.-Air Quality (KORUS-AQ) science team. This effort is aimed at providing direct NASA Distributed Active Archive Center (DAAC) support to an airborne field study. Working closely with the science team, the ASDC developed a scalable architecture that allows investigators to easily upload and distribute their data and documentation within a secure collaborative environment. The user interface leverages modern design elements to intuitively guide the PI through each step of the data management process. In addition, the new framework creates an abstraction layer between how the data files are stored and how the data itself is organized(i.e. grouping files by PI). This approach makes it easy for PIs to simply transfer their data to one directory, while the system itself can automatically group/sort data as needed. Moreover, the platform is "server agnostic" to a certain degree, making deployment and customization more straightforward as hardware needs change. This flexible design will improve development efficiency and can be leveraged for future field campaigns. This presentation will examine the KORUS-AQ data portal as a scalable solution that applies consistent and intuitive usability design practices to support ingest and management of airborne

  4. ExoMars Trace Gas Orbiter Instrument Modelling Approach to Streamline Science Operations

    Science.gov (United States)

    Munoz Fernandez, Michela; Frew, David; Ashman, Michael; Cardesin Moinelo, Alejandro; Garcia Beteta, Juan Jose; Geiger, Bernhard; Metcalfe, Leo; Nespoli, Federico; Muniz Solaz, Carlos

    2018-05-01

    ExoMars Trace Gas Orbiter (TGO) science operations activities are centralised at ESAC's Science Operations Centre (SOC). The SOC receives the inputs from the principal investigators (PIs) in order to implement and deliver the spacecraft pointing requests and instrument timelines to the Mission Operations Centre (MOC). The high number of orbits per planning cycle has made it necessary to abstract the planning interactions between the SOC and the PI teams at the observation level. This paper describes the modelling approach we have conducted for TGOís instruments to streamline science operations. We have created dynamic observation types that scale to adapt to the conditions specified by the PI teams including observation timing, and pointing block parameters calculated from observation geometry. This approach is considered and improvement with respect to previous missions where the generation of the observation pointing and commanding requests was performed manually by the instrument teams. Automation software assists us to effectively handle the high density of planned orbits with increasing volume of scientific data and to successfully meet opportunistic scientific goals and objectives. Our planning tool combines the instrument observation definition files provided by the PIs together with the flight dynamics products to generate the Pointing Requests and the instrument timeline (ITL). The ITL contains all the validated commands at the TC sequence level and computes the resource envelopes (data rate, power, data volume) within the constraints. At the SOC, our main goal is to maximise the science output while minimising the number of iterations among the teams, ensuring that the timeline does not violate the state transitions allowed in the Mission Operations Rules and Constraints Document.

  5. Effects of plasma jet parameters, ionization, thermal conduction, and radiation on stagnation conditions of an imploding plasma liner

    Science.gov (United States)

    Stanic, Milos

    The disciplines of High Energy Density Physics (HEDP) and Inertial Confinement Fusion (ICF) are characterized by hypervelocity implosions and strong shocks. The Plasma Liner Experiment (PLX) is focused on reaching HEDP and/or ICF relevant regimes in excess of 1 Mbar peak pressure by the merging and implosion of discrete plasma jets, as a potentially efficient path towards these extreme conditions in a laboratory. In this work we have presented the first 3D simulations of plasma liner, formation, and implosion by the merging of discrete plasma jets in which ionization, thermal conduction, and radiation are all included in the physics model. The study was conducted by utilizing a smoothed particle hydrodynamics code (SPHC) and was a part of the plasma liner experiment (PLX). The salient physics processes of liner formation and implosion are studied, namely vacuum propagation of plasma jets, merging of the jets (liner forming), implosion (liner collapsing), stagnation (peak pressure), and expansion (rarefaction wave disassembling the target). Radiative transport was found to significantly reduce the temperature of the liner during implosion, thus reducing the thermal expansion rates and leaving more pronounced gradients in the plasma liner during the implosion compared with ideal hydrodynamic simulations. These pronounced gradients lead to a greater sensitivity of initial jet geometry and symmetry on peak pressures obtained. Accounting for ionization and transport, many cases gave higher peak pressures than the ideal hydrodynamic simulations. Scaling laws were developed accordingly, creating a non-dimensional parameter space in which performance of an imploding plasma jet liner can be estimated. It is shown that HEDP regimes could be reached with ≈ 5 MJ of liner energy, which would translate to roughly 10 to 20 MJ of stored (capacitor) energy. This is a potentially significant improvement over the currently available means via ICF of achieving HEDP and nuclear

  6. Brownfields Assessing Contractor Capabilities for Streamlined Site Investigations -- Additional Information Regarding All Appropriate Inquiries and Hiring an Environmental Professional (November 2006)

    Science.gov (United States)

    Guidance for Brownfields grantees and other decision makers to assess the capabilities of contractors and consultants to determine their qualifications to provide streamlined and innovative strategies for the assessment and cleanup of brownfields.

  7. Botulinum Toxin A for Oral Cavity Cancer Patients: In Microsurgical Patients BTX Injections in Major Salivary Glands Temporarily Reduce Salivary Production and the Risk of Local Complications Related to Saliva Stagnation

    OpenAIRE

    Corradino, Bartolo; Lorenzo, Sara Di; Moschella, Francesco

    2012-01-01

    In patients suffering from oral cavity cancer surgical treatment is complex because it is necessary to remove carcinoma and lymph node metastasis (through a radical unilateral or bilateral neck dissection) and to reconstruct the affected area by means of free flaps. The saliva stagnation in the post-operative period is a risk factor with regard to local complications. Minor complications related to saliva stagnation (such as tissue maceration and wound dehiscence) could become major complicat...

  8. Meanline Analysis of Turbines with Choked Flow in the Object-Oriented Turbomachinery Analysis Code

    Science.gov (United States)

    Hendricks, Eric S.

    2016-01-01

    The Object-Oriented Turbomachinery Analysis Code (OTAC) is a new meanline/streamline turbomachinery modeling tool being developed at NASA GRC. During the development process, a limitation of the code was discovered in relation to the analysis of choked flow in axial turbines. This paper describes the relevant physics for choked flow as well as the changes made to OTAC to enable analysis in this flow regime.

  9. The effect of buoyancy on flow and heat transfer in curved pipes

    OpenAIRE

    Mochizuki, Munekazu; Ishigaki, Hiroshi; 望月 宗和; 石垣 博

    1994-01-01

    Fully developed laminar flow in a heated horizontal curved pipe is studied numerically. The thermal boundary conditions at the wall are uniform wall heat flux axially and uniform wall temperature peripherally. Flow and heat transfer are governed by Dean number, Prandtl number and buoyancy number. Detailed prediction of the friction factor, average heat transfer rate, velocity profile, temperature profile and secondary-flow streamlines are given.

  10. Flow behaviour in a CANDU horizontal fuel channel from stagnant subcooled initial conditions

    International Nuclear Information System (INIS)

    Caplan, M.Z.; Gulshani, P.; Holmes, R.W.; Wright, A.C.D.

    1984-01-01

    The flow behaviour in a CANDU primary system with horizontal fuel channels is described following a small inlet header break. With the primary pumps running, emergency coolant injection is in the forward direction so that the channel outlet feeders remain warmer than the inlet thereby promoting forward natural circulation. However, the break force opposes the forward driving force. Should the primary pumps run down after the circuit has refilled, there is a break size for which the natural circulation force is balanced by the break force and channels could, theoretically, stagnate. Result of visualization and of full-size channel tests on channel flow behaviour from an initially stagnant channel condition are discussed. After a channel stagnation, the decay power heats the coolant to saturation. Steam is then formed and the coolant stratifies. The steam expands into the subcooled water in the end fitting in a chugging type of flow regime due to steam condensation. After the end fitting reaches the saturation temperature, steam is able to penetrate into the vertical feeder thereby initiating a large buoyancy induced flow which refills the channel. The duration of stagnation is shown to be sensitive to small asymmetries in the initial conditions. A small initial flow can significantly shorten the occurrence and/or duration of boiling as has been confirmed by reactor experience. (author)

  11. DIDACTICS: DEVELOPMENT OR STAGNATION?

    Directory of Open Access Journals (Sweden)

    I. P. Smirnov

    2016-01-01

    Full Text Available ARTICLE RETRACTEDThe aim of the paper – the detailed analysis of the monograph «Contents and Structure of Regularities of Process of Training (Theory and Experiment» which is written by the corresponding member of the Russian Academy of Education (RAE, Doctor of pedagogical sciences, Professor I. I. Logvinov. The book was included into a series «Basic researches of institute of the theory and history of pedagogics of the Russian Academy of Education. Proceedings 2008–2012».The review of the monograph of I. I. Logvinov has become a reason for reflections of the author of the present publication about actual, most burning issues of a modern Russian educational system: on the status of pedagogics in modern domestic science; evolutions of didactic knowledge and its typology; quality of dissertation researches and emasculation in scientific pedagogical concepts of the fundamental bases; ideologization of didactics and a role of the state in this process.Sorting basic thesis of I. I. Logvinov’s work, in something agreeing, and in something arguing with the scientist, the author of article claims that it is a serious and necessary work where the extremely important questions concerning the most painful points of the Russian pedagogical science and a condition of our education in general are brought up.

  12. Heating plant privatization stagnates

    International Nuclear Information System (INIS)

    Janoska, J.; Benka, M.; Sobinkovic, B.; Haluza, I.

    2005-01-01

    The state has been talking about privatization of 6 municipal heating plants since 2001. The tenders were to start last year. But nothing has happened and the future is uncertain. The city councils would prefer to receive, if not 100%, then at least a majority stake in the heating plants free of charge. But the Cabinet has decided to sell 51% to investors. The privatization agency - the National Property Fund (FNM) is preparing a proposal to increase the stake offered for sale to 67%. According to information provided by the FNM the sale will begin after Cabinet approval. The Fund intends to apply the same model to the sale of all the heating plants. Last year, a major German company Verbundnetz Gas declared its interest in purchasing large municipal heating plants in Slovakia. But it has been waiting for a response ever since. The French company - Dalkia, which has 10-years' experience of doing business in Slovakia, is interested in all the heating plants to be offered for sale. The Austrian company - Stefe is not new to the business either, it is interested mainly in the regions where it has already established itself - Central and Eastern Slovakia. Strategic investors expect financial groups to show interest too. The Penta Group has not hid its ambitions - it has already privatised a company which represents the key to the future development of heat management in Bratislava - Paroplynovy cyklus. Whereas Penta is not new to the heat production business another financial group - Slavia Capital is still surveying the sector. Should it not succeed, it plans several projects that would allow it to take a stake in the sector

  13. Breathtaking or stagnation?

    DEFF Research Database (Denmark)

    Sauer, Johannes; Graversen, Jesper Tranbjerg; Park, Tim

    2006-01-01

    in technical change as well as a general index model specification. Input specific bias in technical change as well elasticities of input substitution are analyzed. Factors for the development of technical change and the change in efficiency over time are investigated by applying a bootstrapped ITSUR...

  14. A topological method for vortex identification in turbulent flows

    Energy Technology Data Exchange (ETDEWEB)

    Zhong, Qiang; Chen, Huai; Li, Danxun [State Key Laboratory of Hydroscience and Engineering, Tsinghua University, Beijing 100084 (China); Chen, Qigang, E-mail: lidx@mail.tsinghua.edu.cn [School of Civil Engineering, Beijing Jiaotong University, Beijing 100044 (China)

    2017-02-15

    We present a novel vortex identification method based on structured vorticity ( ω {sub s}) of the direction field of flow (velocity vectors set to unit magnitude). As a direct measure of streamline curvature is insensitive to vortex strength, ω {sub s} is effective in detecting vortices of various strengths. The effectiveness has been tested against both analytical flows (pure shear flow, Oseen vortex flow, strong outward spiraling motion, straining flow, Taylor–Green flow) and experimental flows (closed cavity flow, closed and open channel flow). Comparison of the new method with the swirling-strength method indicates that the new method shows promise as being a simple and effective criterion for vortex identification. (paper)

  15. PIV pictures of stream field predict haemolysis index of centrifugal pump with streamlined impeller.

    Science.gov (United States)

    Qian, K X; Feng, Z G; Ru, W M; Zeng, P; Yuan, H Y

    2007-01-01

    Previously it has been found by pump haemolysis testing that the flow rate has a remarkable effect on index of haemolysis (IH), while pressure head does not affect IH. Recent investigation with particle image velocimetry (PIV) technology has demonstrated that IH is directly related to the flow pattern of stream field in impeller vane channels. PIV is a visible approach showing the real flow status in the pump. The different positions of a tracer particle in two PIV pictures taken at 20 micros intervals decide the velocity value and direction. The velocity vectors of many particles draw the flow pattern of the stream field. The same pictures are taken at 2, 4 and 6 l min(-1) flow rates while the pressure head is kept unchanged at 100 mmHg; then the pictures are taken at 4 l min(-1) flow with different pressure heads of 80, 100 and 120 mmHg. Results reveal that the flow rate of 4 l min(-1) (IH = 0.030) has the best stream field, and neither turbulence nor separation can be seen. In other flow rates (IH: 0.048 - 0.082), there is obviously second flow. Meanwhile, no significant difference can be seen among the PIV pictures of different pressure heads pumped, which agrees with the results of haemolysis testing showing that pressure has no effect on pump haemolysis. It may be concluded that the haemolysis property of a centrifugal pump can be assessed approximately by PIV pictures, which are much easier to take than haemolysis tests.

  16. Homogeneous nonequilibrium critical flashing flow with a cavity flooding model

    International Nuclear Information System (INIS)

    Lee, S.Y.; Schrock, V.E.

    1989-01-01

    The primary purpose of the work presented here is to describe the model for pressure undershoot at incipient flashing in the critical flow of straight channels (Fanno-type flow) for subcooled or saturated stagnation conditions on a more physical basis. In previous models, a modification of the pressure undershoot prediction of Alamgir and Lienhard was used. Their method assumed nucleation occurs on the bounding walls as a result of molecular fluctuations. Without modification it overpredicts the pressure undershoot. In the present work the authors develop a mechanistic model for nucleation from wall cavities. This physical concept is more consistent with experimental data

  17. Thermophysical aspects of re-entry flows

    International Nuclear Information System (INIS)

    Moss, J.N.; Scott, C.D.

    1986-01-01

    The present conference discusses low density aerothermodynamics, the drag of bodies in rarefied hypersonic flow, transitional hypervelocity aerodynamic simulation and scaling, high temperature kinetics and transport properties, electron-nitrogen molecule collisions in high temperature nonequilibrium air, theoretical studies of dissociative recombination, the transport properties of some atom/ion interactions in air, and the interaction energies, dipole transition moments, and transport cross sections of N(+)-N and O(+)-O. Also discussed are the results of studies of potential fluid mechanisms for enhanced stagnation heating, vortex-induced leeward heating on a biconic at Mach 6 and 10, the effects of surface discontinuities on convective heat transfer in hypersonic flow, computational convergence in chemical reacting flows, and three-dimensional viscous shock layer applications for the Space Shuttle Orbiter

  18. Faradaic AC Electrokinetic Flow and Particle Traps

    Science.gov (United States)

    Ben, Yuxing; Chang, Hsueh-Chia

    2004-11-01

    Faradaic reaction at higher voltages can produce co-ion polarization at AC electrodes instead of counter-ion polarization due to capacitive charging from the bulk. The Faradaic co-ion polarization also does not screen the external field and hence can produce large net electro-kinetic flows at frequencies lower than the inverse RC time of the double layer. Due to the opposite polarization of capacitve and Faradaic charging, we can reverse the direction of AC flows on electrodes by changing the voltage and frequency. Particles and bacteria are trapped and then dispersed at stagnation lines, at locations predicted by our theory, by using these two flows sequentially. This technique offers a good way to concentrate and detect bacteria.

  19. Flow deflection over a foredune

    Science.gov (United States)

    Hesp, Patrick A.; Smyth, Thomas A. G.; Nielsen, Peter; Walker, Ian J.; Bauer, Bernard O.; Davidson-Arnott, Robin

    2015-02-01

    Flow deflection of surface winds is common across coastal foredunes and blowouts. Incident winds approaching obliquely to the dune toe and crestline tend to be deflected towards a more crest-normal orientation across the stoss slope of the foredune. This paper examines field measurements for obliquely incident winds, and compares them to computational fluid dynamics (CFD) modelling of flow deflection in 10° increments from onshore (0°) to alongshore (90°) wind approach angles. The mechanics of flow deflection are discussed, followed by a comparative analysis of measured and modelled flow deflection data that shows strong agreement. CFD modelling of the full range of onshore to alongshore incident winds reveals that deflection of the incident wind flow is minimal at 0° and gradually increases as the incident wind turns towards 30° to the dune crest. The greatest deflection occurs between 30° and 70° incident to the dune crest. The degree of flow deflection depends secondarily on height above the dune surface, with the greatest effect near the surface and toward the dune crest. Topographically forced flow acceleration ("speed-up") across the stoss slope of the foredune is greatest for winds less than 30° (i.e., roughly perpendicular) and declines significantly for winds with more oblique approach angles. There is less lateral uniformity in the wind field when the incident wind approaches from > 60° because the effect of aspect ratio on topographic forcing and streamline convergence is less pronounced.

  20. Discussion of boundary-layer characteristics near the casing of an axial-flow compressor

    Science.gov (United States)

    Mager, Artur; Mahoney, John J; Budinger, Ray E

    1951-01-01

    Boundary-layer velocity profiles on the casing of an axial-flow compressor behind the guide vanes and rotor were measured and resolved into two components: along the streamline of the flow and perpendicular to it. Boundary-layer thickness and the deflection of the boundary layer at the wall were the generalizing parameters. By use of these results and the momentum-integral equations, the characteristics of boundary on the walls of axial-flow compressor are qualitatively discussed. Important parameters concerning secondary flow in the boundary layer appear to be turning of the flow and the product of boundary-layer thickness and streamline curvature outside the boundary layer. Two types of separation are shown to be possible in three dimensional boundary layer.

  1. Two-phase flow experiments through intergranular stress corrosion cracks

    International Nuclear Information System (INIS)

    Collier, R.P.; Norris, D.M.

    1984-01-01

    Experimental studies of critical two-phase water flow, through simulated and actual intergranular stress corrosion cracks, were performed to obtain data to evaluate a leak flow rate model and investigate acoustic transducer effectiveness in detecting and sizing leaks. The experimental program included a parametric study of the effects of crack geometry, fluid stagnation pressure and temperature, and crack surface roughness on leak flow rate. In addition, leak detection, location, and leak size estimation capabilities of several different acoustic transducers were evaluated as functions of leak rate and transducer position. This paper presents flow rate data for several different cracks and fluid conditions. It also presents the minimum flows rate detected with the acoustic sensors and a relationship between acoustic signal strength and leak flow rate

  2. Estimation of flow rates through intergranular stress corrosion cracks

    International Nuclear Information System (INIS)

    Collier, R.P.; Norris, D.M.

    1984-01-01

    Experimental studies of critical two-phase water flow, through simulated and actual intergranular stress corrosion cracks, were performed to obtain data to evaluate a leak flow rate model and investigate acoustic transducer effectiveness in detecting and sizing leaks. The experimental program included a parametric study of the effects of crack geometry, fluid stagnation pressure and temperature, and crack surface roughness on leak flow rate. In addition, leak detection, location, and leak size estimation capabilities of several different acoustic transducers were evaluated as functions of leak rate and transducer position. This paper presents flow rate data for several different cracks and fluid conditions. It also presents the minimum flow rate detected with the acoustic sensors and a relationship between acoustic signal strength and leak flow rate

  3. Edge maps: Representing flow with bounded error

    KAUST Repository

    Bhatia, Harsh

    2011-03-01

    Robust analysis of vector fields has been established as an important tool for deriving insights from the complex systems these fields model. Many analysis techniques rely on computing streamlines, a task often hampered by numerical instabilities. Approaches that ignore the resulting errors can lead to inconsistencies that may produce unreliable visualizations and ultimately prevent in-depth analysis. We propose a new representation for vector fields on surfaces that replaces numerical integration through triangles with linear maps defined on its boundary. This representation, called edge maps, is equivalent to computing all possible streamlines at a user defined error threshold. In spite of this error, all the streamlines computed using edge maps will be pairwise disjoint. Furthermore, our representation stores the error explicitly, and thus can be used to produce more informative visualizations. Given a piecewise-linear interpolated vector field, a recent result [15] shows that there are only 23 possible map classes for a triangle, permitting a concise description of flow behaviors. This work describes the details of computing edge maps, provides techniques to quantify and refine edge map error, and gives qualitative and visual comparisons to more traditional techniques. © 2011 IEEE.

  4. Interaction of single-pulse laser energy with bow shock in hypersonic flow

    Directory of Open Access Journals (Sweden)

    Hong Yanji

    2014-04-01

    Full Text Available Pressure sensing and schlieren imaging with high resolution and sensitivity are applied to the study of the interaction of single-pulse laser energy with bow shock at Mach 5. An Nd:YAG laser operated at 1.06 μm, 100 mJ pulse energy is used to break down the hypersonic flow in a shock tunnel. Three-dimensional Navier–Stokes equations are solved with an upwind scheme to simulate the interaction. The pressure at the stagnation point on the blunt body is measured and calculated to examine the pressure variation during the interaction. Schlieren imaging is used in conjunction with the calculated density gradients to examine the process of the interaction. The results show that the experimental pressure at the stagnation point on the blunt body and schlieren imaging fit well with the simulation. The pressure at the stagnation point on the blunt body will increase when the transmission shock approaches the blunt body and decrease with the formation of the rarefied wave. Bow shock is deformed during the interaction. Quasi-stationary waves are formed by high rate laser energy deposition to control the bow shock. The pressure and temperature at the stagnation point on the blunt body and the wave drag are reduced to 50%, 75% and 81% respectively according to the simulation. Schlieren imaging has provided important information for the investigation of the mechanism of the interaction.

  5. Large-scale renewable energy project barriers: Environmental impact assessment streamlining efforts in Japan and the EU

    International Nuclear Information System (INIS)

    Schumacher, Kim

    2017-01-01

    Environmental Impact Assessment (EIA) procedures have been identified as a major barrier to renewable energy (RE) development with regards to large-scale projects (LS-RE). However EIA laws have also been neglected by many decision-makers who have been underestimating its impact on RE development and the stifling potential they possess. As a consequence, apart from acknowledging the shortcomings of the systems currently in place, few governments momentarily have concrete plans to reform their EIA laws. By looking at recent EIA streamlining efforts in two industrialized regions that underwent major transformations in their energy sectors, this paper attempts to assess how such reform efforts can act as a means to support the balancing of environmental protection and climate change mitigation with socio-economic challenges. Thereby this paper fills this intellectual void by identifying the strengths and weaknesses of the Japanese EIA law by contrasting it with the recently revised EIA Directive of the European Union (EU). This enables the identification of the regulatory provisions that impact RE development the most and the determination of how structured EIA law reforms would affect domestic RE project development. The main focus lies on the evaluation of regulatory streamlining efforts in the Japanese and EU contexts through the application of a mixed-methods approach, consisting of in-depth literary and legal reviews, followed by a comparative analysis and a series of semi-structured interviews. Highlighting several legal inconsistencies in combination with the views of EIA professionals, academics and law- and policymakers, allowed for a more comprehensive assessment of what streamlining elements of the reformed EU EIA Directive and the proposed Japanese EIA framework modifications could either promote or stifle further RE deployment. - Highlights: •Performs an in-depth review of EIA reforms in OECD territories •First paper to compare Japan and the European

  6. Patient and physician attitudes regarding risk and benefit in streamlined development programmes for antibacterial drugs: a qualitative analysis.

    Science.gov (United States)

    Holland, Thomas L; Mikita, Stephen; Bloom, Diane; Roberts, Jamie; McCall, Jonathan; Collyar, Deborah; Santiago, Jonas; Tiernan, Rosemary; Toerner, Joseph

    2016-11-10

    To explore patient, caregiver and physician perceptions and attitudes regarding the balance of benefit and risk in using antibacterial drugs developed through streamlined development processes. Semistructured focus groups and in-depth interviews were conducted to elicit perceptions and attitudes about the use of antibacterial drugs to treat multidrug-resistant infections. Participants were given background information about antibiotic resistance, streamlined drug development programmes and FDA drug approval processes. Audio recordings of focus groups/interviews were reviewed and quotes excerpted and categorised to identify key themes. Two primary stakeholder groups were engaged: one comprising caregivers, healthy persons and patients who had recovered from or were at risk of resistant infection (N=67; 11 focus groups); and one comprising physicians who treat resistant infections (N=23). Responses from focus groups/interviews indicated widespread awareness among patients/caregivers and physicians of the seriousness of the problem of antibacterial resistance. Both groups were willing to accept a degree of uncertainty regarding the balance of risk and benefit in a new therapy where a serious unmet need exists, but also expressed a desire for rigorous monitoring and rapid, transparent reporting of safety/effectiveness data. Both groups wanted to ensure that >1 physician had input on whether to treat patients with antibiotics developed through a streamlined process. Some patients/caregivers unfamiliar with exigencies of critical care suggested a relatively large multidisciplinary team, while physicians believed individual expert consultations would be preferable. Both groups agreed that careful oversight and stewardship of antibacterial drugs are needed to ensure patient safety, preserve efficacy and prevent abuse. Groups comprising patients/caregivers and physicians were aware of serious issues posed by resistant infections and the lack of effective antibacterial drug

  7. Influence of de qi on the immediate analgesic effect of SP6 acupuncture in patients with primary dysmenorrhoea and cold and dampness stagnation: a multicentre randomised controlled trial.

    Science.gov (United States)

    Zhao, Min-Yi; Zhang, Peng; Li, Jing; Wang, Lin-Peng; Zhou, Wei; Wang, Yan-Xia; She, Yan-Fen; Ma, Liang-Xiao; Wang, Pei; Hu, Ni-Juan; Lin, Chi; Hu, Shang-Qin; Wu, Gui-Wen; Wang, Ya-Feng; Sun, Jun-Jun; Jiang, Si-Zhu; Zhu, Jiang

    2017-10-01

    The aim of this multicentre randomised controlled trial was to investigate the contribution of de qi to the immediate analgesic effect of acupuncture in patients with primary dysmenorrhoea and the specific traditional Chinese medicine diagnosis cold and dampness stagnation . Eighty-eight patients with primary dysmenorrhoea and cold and dampness stagnation were randomly assigned to de qi (n=43) or no de qi (n=45) groups and underwent 30 min of SP6 acupuncture. The de qi group received deep needling at SP6 with manipulation using thick needles; the no de qi group received shallow needling with no manipulation using thin needles. In both groups the pain scores and actual de qi sensation were evaluated using a visual analogue scale for pain (VAS-P) and the acupuncture de qi clinical assessment scale (ADCAS), respectively. Both groups showed reductions in VAS-P, with no signficant differences between groups. ADCAS scores showed 43/43 and 25/45 patients in de qi and no de qi groups, respectively, actually experienced de qi sensation. Independent of original group allocation, VAS-P reductions associated with actual de qi (n=68) were greater than those without (28.4±18.19 mm vs 14.6±12.28 mm, p=0.008). This study showed no significant difference in VAS-P scores in patients with primary dysmenorrhoea and cold and dampness stagnation immediately after SP6 acupuncture designed to induce or avoid de qi sensation. Both treatments significantly reduced VAS-P relative to baseline. Irrespective of group allocation, patients experiencing actual de qi sensation demonstrated larger reductions in pain score relative to those without, suggesting greater analgesic effects. Chinese Clinical Trial Registry (ChiCTR-TRC-13003086); Results. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

  8. Biological nitrate transport in sediments on the Peruvian margin mitigates benthic sulfide emissions and drives pelagic N loss during stagnation events

    Science.gov (United States)

    Dale, A. W.; Sommer, S.; Lomnitz, U.; Bourbonnais, A.; Wallmann, K.

    2016-06-01

    Benthic N cycling in the Peruvian oxygen minimum zone (OMZ) was investigated at ten stations along 12 °S from the middle shelf (74 m) to the upper slope (1024 m) using in situ flux measurements, sediment biogeochemistry and modeling. Middle shelf sediments were covered by mats of the filamentous bacteria Thioploca spp. and contained a large 'hidden' pool of nitrate that was not detectable in the porewater. This was attributed to a biological nitrate reservoir stored within the bacteria to oxidize sulfide during 'dissimilatory nitrate reduction to ammonium' (DNRA). The extremely high rates of DNRA on the shelf (15.6 mmol m-2 d-1 of N), determined using an empirical steady-state model, could easily supply all the ammonium requirements for anammox in the water column. The model further showed that denitrification by foraminifera may account for 90% of N2 production at the lower edge of the OMZ. At the time of sampling, dissolved oxygen was below detection limit down to 400 m and the water body overlying the shelf had stagnated, resulting in complete depletion of nitrate and nitrite. A decrease in the biological nitrate pool was observed on the shelf during fieldwork concomitant with a rise in porewater sulfide levels in surface sediments to 2 mM. Using a non-steady state model to simulate this natural anoxia experiment, these observations were shown to be consistent with Thioploca surviving on a dwindling intracellular nitrate reservoir to survive the stagnation period. The model shows that sediments hosting Thioploca are able to maintain high ammonium fluxes for many weeks following stagnation, potentially sustaining pelagic N loss by anammox. In contrast, sulfide emissions remain low, reducing the economic risk to the Peruvian fishery by toxic sulfide plume development.

  9. Life Disparity before, during and after Stagnation of Danish Female Life Expectancy. a Cause of Death Analysis and a Comparison with Their Scandinavian Counterparts

    DEFF Research Database (Denmark)

    Aburto, José Manuel; Wensink, Maarten Jan; Lindahl-Jacobsen, Rune

    that as Norway increasingly came to resemble Sweden in terms of high life expectancy, it also came to resemble Sweden in terms of low lifespan inequality. Next, we aim to make similar decompositions for Sweden and Norway, and aim to disentangle cohort effects from the question: what can Denmark do now...... cancers and non-infectious respiratory diseases, offsetting continuous improvement in cardiovascular mortality. Before and after stagnation, life expectancy increased as disparity decreased, as the cardiovascular revolution unfolded. Comparing Denmark and its Scandinavian counterparts, we find...

  10. Flow topology of rare back flow events and critical points in turbulent channels and toroidal pipes

    Science.gov (United States)

    Chin, C.; Vinuesa, R.; Örlü, R.; Cardesa, J. I.; Noorani, A.; Schlatter, P.; Chong, M. S.

    2018-04-01

    A study of the back flow events and critical points in the flow through a toroidal pipe at friction Reynolds number Re τ ≈ 650 is performed and compared with the results in a turbulent channel flow at Re τ ≈ 934. The statistics and topological properties of the back flow events are analysed and discussed. Conditionally-averaged flow fields in the vicinity of the back flow event are obtained, and the results for the torus show a similar streamwise wall-shear stress topology which varies considerably for the spanwise wall-shear stress when compared to the channel flow. The comparison between the toroidal pipe and channel flows also shows fewer back flow events and critical points in the torus. This cannot be solely attributed to differences in Reynolds number, but is a clear effect of the secondary flow present in the toroidal pipe. A possible mechanism is the effect of the secondary flow present in the torus, which convects momentum from the inner to the outer bend through the core of the pipe, and back from the outer to the inner bend through the pipe walls. In the region around the critical points, the skin-friction streamlines and vorticity lines exhibit similar flow characteristics with a node and saddle pair for both flows. These results indicate that back flow events and critical points are genuine features of wall-bounded turbulence, and are not artifacts of specific boundary or inflow conditions in simulations and/or measurement uncertainties in experiments.

  11. Large Eddy Simulation of stratified flows over structures

    OpenAIRE

    Brechler J.; Fuka V.

    2013-01-01

    We tested the ability of the LES model CLMM (Charles University Large-Eddy Microscale Model) to model the stratified flow around three dimensional hills. We compared the quantities, as the height of the dividing streamline, recirculation zone length or length of the lee waves with experiments by Hunt and Snyder[3] and numerical computations by Ding, Calhoun and Street[5]. The results mostly agreed with the references, but some important differences are present.

  12. Large Eddy Simulation of stratified flows over structures

    Directory of Open Access Journals (Sweden)

    Brechler J.

    2013-04-01

    Full Text Available We tested the ability of the LES model CLMM (Charles University Large-Eddy Microscale Model to model the stratified flow around three dimensional hills. We compared the quantities, as the height of the dividing streamline, recirculation zone length or length of the lee waves with experiments by Hunt and Snyder[3] and numerical computations by Ding, Calhoun and Street[5]. The results mostly agreed with the references, but some important differences are present.

  13. Large Eddy Simulation of stratified flows over structures

    Science.gov (United States)

    Fuka, V.; Brechler, J.

    2013-04-01

    We tested the ability of the LES model CLMM (Charles University Large-Eddy Microscale Model) to model the stratified flow around three dimensional hills. We compared the quantities, as the height of the dividing streamline, recirculation zone length or length of the lee waves with experiments by Hunt and Snyder[3] and numerical computations by Ding, Calhoun and Street[5]. The results mostly agreed with the references, but some important differences are present.

  14. Experimental Evidence of Helical Flow in Porous Media

    DEFF Research Database (Denmark)

    Ye, Yu; Chiogna, Gabriele; Cirpka, Olaf A.

    2015-01-01

    Helical flow leads to deformation of solute plumes and enhances transverse mixing in porous media. We present experiments in which macroscopic helical flow is created by arranging different materials to obtain an anisotropic macroscopic permeability tensor with spatially variable orientation....... The resulting helical flow entails twisting streamlines which cause a significant increase in lateral mass exchange and thus a large enhancement of plume dilution (up to 235%) compared to transport in homogenous media. The setup may be used to effectively mix solutes in parallel streams similarly to static...... mixers, but in porous media....

  15. Numerical study of homogeneous–heterogeneous reactions in Sisko fluid flow past a stretching cylinder

    Directory of Open Access Journals (Sweden)

    Rabia Malik

    2018-03-01

    Full Text Available The motivation behind the present study is to focus on the effects of stagnation-point flow and heat transfer to the Sisko fluid past an impermeable stretching cylinder involving convective boundary conditions with homogeneous–heterogeneous reactions. Diffusion coefficients of species A and B are assumed to be of the same size. Also, it is assumed that heat released during chemical reaction is negligible. A system of governing ordinary differential equations is obtained by using suitable transformations which are then solved numerically by means of the shooting method combined with Runge-Kutta method. The obtained numerical results are then presented in graphical and tabular form and are discussed at length. The results obtained reveal that the concentration profile decreases with increasing homogeneous and heterogeneous reactions parameters. Keywords: Homogeneous–heterogeneous reactions, Non-linearly stretching cylinder, Stagnation-point flow, Convective boundary conditions, Sisko fluid

  16. Topological fluid dynamics of interfacial flows

    DEFF Research Database (Denmark)

    Brøns, Morten

    1994-01-01

    The topological description of flows in the vicinity of a solid boundary, that is familiar from the aerodynamics literature, has recently been extended to the case of flow at a liquid–gas interface or a free surface by Lugt [Phys. Fluids 30, 3647 (1987)]. Lugt's work is revisited in a more general...... setting, including nonconstant curvature of the interface and gradients of surface tension, using tools of modern nonlinear dynamics. Bifurcations of the flow pattern occur at degenerate configurations. Using the theory of unfolding, this paper gives a complete description of the bifurcations that depend...... on terms up to the second order. The general theory of this paper is applied to the topology of streamlines during the breaking of a wave and to the flow below a stagnant surface film. Physics of Fluids is copyrighted by The American Institute of Physics....

  17. Flow and scour around spherical bodies

    DEFF Research Database (Denmark)

    Truelsen, Christoffer

    2003-01-01

    Spherical bodies placed in the marine environment may bury themselves due to the action of the waves and the current on the sediment in their immediate neighborhood. The present study addresses this topic by a numerical and an experimental investigation of the flow and scour around a spherical body...... results except in the critical flow regime. For flow around a near-wall sphere, a weak horseshoe vortex emerges as the gap ratio becomes less than or equal to 0.3. In Chapter 3, a RANS flow solver has been used to compute the bed shear stress for a near-wall sphere. The model results compare well...... 4, an experimental study on the scour around spherical bodies and self-burial in sand for steady current and waves has been carried out. The effect of the contraction of streamlines is found to be the key element in the scour process both for steady current and waves. Furthermore, it is demonstrated...

  18. Direct numerical simulation of laminar-turbulent flow over a flat plate at hypersonic flow speeds

    Science.gov (United States)

    Egorov, I. V.; Novikov, A. V.

    2016-06-01

    A method for direct numerical simulation of a laminar-turbulent flow around bodies at hypersonic flow speeds is proposed. The simulation is performed by solving the full three-dimensional unsteady Navier-Stokes equations. The method of calculation is oriented to application of supercomputers and is based on implicit monotonic approximation schemes and a modified Newton-Raphson method for solving nonlinear difference equations. By this method, the development of three-dimensional perturbations in the boundary layer over a flat plate and in a near-wall flow in a compression corner is studied at the Mach numbers of the free-stream of M = 5.37. In addition to pulsation characteristic, distributions of the mean coefficients of the viscous flow in the transient section of the streamlined surface are obtained, which enables one to determine the beginning of the laminar-turbulent transition and estimate the characteristics of the turbulent flow in the boundary layer.

  19. Bioprofiling of unknown antibiotics in herbal extracts: Development of a streamlined direct bioautography using Bacillus subtilis linked to mass spectrometry.

    Science.gov (United States)

    Jamshidi-Aidji, Maryam; Morlock, Gertrud E

    2015-11-13

    Working in the field of profiling and identification of bioactive compounds in herbal extracts is faced with the challenge that common chromatographic methods do not directly link to bioactive compounds. Direct bioautography, the combination of TLC/HPTLC with bioassays, linked to structure elucidating techniques is demonstrated to overcome this challenge. The combination of TLC and Bacillus subtilis bioassay was already demonstrated to detect the antibiotics in samples. However, previous studies in this field were faced with some challenges, like being time-consuming, leading not to a homogenous plate background or being restricted to a non-acidic mobile phase. In this study, these aspects were investigated and a streamlined HPTLC-B. subtilis bioassay was developed that generated a homogenous plate background, which was crucial to yield a good baseline for biodensitometry. Two commonly used broths for B. subtilis and a self-designed medium were compared with regard to their capability of detection and baseline noise. The workflow developed allowed the use of acidic mobile phases for the first time. To prove this, 20 herbal extracts were screened for antimicrobial substances developed in parallel with an acidic mobile phase. The main antimicrobial substance in Salvia officinalis tincture detected was further characterized by microchemical reactions, Aliivibrio fischeri, β-glucosidase and acetylcholinesterase (bio)assays as well as mass spectrometry. Scientists looking for new herbal-based medicine may benefit from this time-saving and streamlined bioactivity profiling. Copyright © 2015 Elsevier B.V. All rights reserved.

  20. The benefits of life cycle inventory parametric models in streamlining data collection. A case study in the wooden pallet sector

    DEFF Research Database (Denmark)

    Niero, Monia; Di Felice, F.; Ren, J.

    2014-01-01

    LCA methodology is time and resource consuming particularly when it comes to data collection and handling, therefore companies, particularly Small and Medium Enterprises (SMEs), are inclined to use streamlined approaches to shorten the resource-consuming life cycle inventory (LCI) phase. An effec......LCA methodology is time and resource consuming particularly when it comes to data collection and handling, therefore companies, particularly Small and Medium Enterprises (SMEs), are inclined to use streamlined approaches to shorten the resource-consuming life cycle inventory (LCI) phase...... study of a SME in the wooden pallet sector, investigating to what extent the use of parametric LCI models can be beneficial both in evaluating the environmental impacts of similar products and in providing a preliminary assessment of the potential environmental impacts of new products. We developed...... an LCI parametric model describing the LCI of a range of wooden pallets and tested its effectiveness with a reference product, namely a non-reversible pallet with four-way blocks. The identified parameters refer to the technical characteristics of the product system, e.g. the number and dimension...

  1. Cardiogenic induction of pluripotent stem cells streamlined through a conserved SDF-1/VEGF/BMP2 integrated network.

    Directory of Open Access Journals (Sweden)

    Anca Chiriac

    Full Text Available BACKGROUND: Pluripotent stem cells produce tissue-specific lineages through programmed acquisition of sequential gene expression patterns that function as a blueprint for organ formation. As embryonic stem cells respond concomitantly to diverse signaling pathways during differentiation, extraction of a pro-cardiogenic network would offer a roadmap to streamline cardiac progenitor output. METHODS AND RESULTS: To resolve gene ontology priorities within precursor transcriptomes, cardiogenic subpopulations were here generated according to either growth factor guidance or stage-specific biomarker sorting. Innate expression profiles were independently delineated through unbiased systems biology mapping, and cross-referenced to filter transcriptional noise unmasking a conserved progenitor motif (55 up- and 233 down-regulated genes. The streamlined pool of 288 genes organized into a core biological network that prioritized the "Cardiovascular Development" function. Recursive in silico deconvolution of the cardiogenic neighborhood and associated canonical signaling pathways identified a combination of integrated axes, CXCR4/SDF-1, Flk-1/VEGF and BMP2r/BMP2, predicted to synchronize cardiac specification. In vitro targeting of the resolved triad in embryoid bodies accelerated expression of Nkx2.5, Mef2C and cardiac-MHC, enhanced beating activity, and augmented cardiogenic yield. CONCLUSIONS: Transcriptome-wide dissection of a conserved progenitor profile thus revealed functional highways that coordinate cardiogenic maturation from a pluripotent ground state. Validating the bioinformatics algorithm established a strategy to rationally modulate cell fate, and optimize stem cell-derived cardiogenesis.

  2. Two-phase flow models in unbounded two-phase critical flows

    International Nuclear Information System (INIS)

    Celata, G.P.; Cumo, M.; Farello, G.E.

    1985-01-01

    With reference to a Loss-of-Coolant Accident in Light Water Reactors, an analysis of the unbounded two-phase critical flow (i.e. the issuing two-phase jet) has been accomplished. Considering jets external shape, obtained by means of photographic pictures; pressure profiles inside the jet, obtained by means of a movable ''Pitot;'' and jet phases distribution information, obtained by means of X-rays pictures; a characterization of the flow pattern in the unbounded region of a two-phase critical flow is given. Jets X-ray pictures show the existence of a central high density ''core'' gradually evaporating all around, which gives place to a characteristic ''dartflow'' the length of which depends on stagnation thermodynamic conditions

  3. Establishing the Basis for Validated Predictions of Highly Non-Equilibrium Flows. (With 9 Attachments)

    Science.gov (United States)

    1993-10-14

    expansion in Figure 8, a finite rate chemistry, inviscid flow solution was calculated using a One Dimensional Kinetics ( ODK ) computer program2 0...T Temperature range (K) 300 < T < 2000 Units cm3 mo-L’ sec-, [able 2: Reaction rate used in ODK compuiations. Working Gas 12 Stagnation pressure (atm...and proceeding to shorter wavelengths. The laser beam was focused on the probed volume with a 30 cm focal length lens. The LIF signal was collected in

  4. Minimising the risk of water hammer and other problems at the beginning of stagnation of solar thermal plants - A theoretical approach

    International Nuclear Information System (INIS)

    Streicher, W.

    2000-01-01

    Solar plants are increasingly used not only for hot tap water heating but also for the assistance of space heating. These plants produce much more energy in summer than needed, which often results in stagnation. Because of stagnation-temperatures of todays selective collectors up to 200 deg. C, the collector fluid evaporates. In several plants a high noise level and a vibration of the plant during this evaporation phase is reported. This is due to the occurrence of water hammers in the system, when liquid collector fluid passes areas where the fluid was already evaporated and superheated. The remaining vapor bubbles deflate rapidly and the liquid phases collide with high velocity, which results in a rapid pressure increase. This paper describes the theory of condensate-induced water hammers and conditions of solar plants, under which this can happen. A simulation model for the evaporation phase of the collector is presented to give a deeper understanding about the influences of solar radiation, the size of the tubing, and the size of the expansion device on the process of the evaporation. Three hydraulic layouts of the collector area are discussed for there possibilities producing water hammers. (au)

  5. The stagnation of the Mexican male life expectancy in the first decade of the 21st century: the impact of homicides and diabetes mellitus.

    Science.gov (United States)

    Canudas-Romo, Vladimir; García-Guerrero, Víctor Manuel; Echarri-Cánovas, Carlos Javier

    2015-01-01

    In the first decade of the 21st century, the Mexican life expectancy changed from a long trend of increase to stagnation. These changes concur with an increase in deaths by homicides that the country experienced in that decade, and an obesity epidemic that had developed over the last decades of the 20th century. We quantify the impact of causes of death on life expectancy from 2000 to 2010. Two approaches to analyse causes of death are used: the number of life years lost due to each of the causes of death in a given year, and cause-decomposition techniques for comparisons of life expectancy from 2000 to 2010. The apparent stagnation in life expectancy is the result of an increase in deaths by homicides and diabetes mellitus on the one hand, and the positive improvements observed in other causes of death on the other. The negative impact of homicides is particularly observed for ages 15 and 50, and for that of diabetes mellitus at ages above 45 years. There is little basis for optimism regarding the future scenarios of the health of the Mexican population based on the first decade of the 21st century. Male life expectancy would have increased by 2 years if deaths by homicides and diabetes mellitus had been avoided. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  6. Non-Hydrostatic Effects in the Interaction between Flow and Orography

    OpenAIRE

    Gladich, Ivan; Stel, F.; Giaiotti, D.; Furlan, G.

    2008-01-01

    The interaction between flows and orography is a fundamental aspect of theoretical fluid dynamics for its direct applications (e.g., in dynamical meteorology); a comprehensive description is nowadays still lacking in some aspects. In this work, in particular, the authors would like to face the problem of flow-blocking and of the streamlines pattern formation, examining the role of stratification (i.e., Brunt-Vaisala frequency) and Froude number on these problems. In particular this work wants...

  7. Utilizing DMAIC six sigma and evidence-based medicine to streamline diagnosis in chest pain.

    Science.gov (United States)

    Kumar, Sameer; Thomas, Kory M

    2010-01-01

    The purpose of this study was to quantify the difference between the current process flow model for a typical patient workup for chest pain and development of a new process flow model that incorporates DMAIC (define, measure, analyze, improve, control) Six Sigma and evidence-based medicine in a best practices model for diagnosis and treatment. The first stage, DMAIC Six Sigma, is used to highlight areas of variability and unnecessary tests in the current process flow for a patient presenting to the emergency department or physician's clinic with chest pain (also known as angina). The next stage, patient process flow, utilizes DMAIC results in the development of a simulated model that represents real-world variability in the diagnosis and treatment of a patient presenting with angina. The third and final stage is used to analyze the evidence-based output and quantify the factors that drive physician diagnosis accuracy and treatment, as well as review the potential for a broad national evidence-based database. Because of the collective expertise captured within the computer-oriented evidence-based model, the study has introduced an innovative approach to health care delivery by bringing expert-level care to any physician triaging a patient for chest pain anywhere in the world. Similar models can be created for other ailments as well, such as headache, gastrointestinal upset, and back pain. This updated way of looking at diagnosing patients stemming from an evidence-based best practice decision support model may improve workflow processes and cost savings across the health care continuum.

  8. Effects of the Meetings-Flow Approach on Quality Teamwork in the Training of Software Capstone Projects

    Science.gov (United States)

    Chen, Chung-Yang; Hong, Ya-Chun; Chen, Pei-Chi

    2014-01-01

    Software development relies heavily on teamwork; determining how to streamline this collaborative development is an essential training subject in computer and software engineering education. A team process known as the meetings-flow (MF) approach has recently been introduced in software capstone projects in engineering programs at various…

  9. Numerical investigation on nonlinear effect and vortex formation of oscillatory flow throughout a short tube in a thermoacoustic Stirling engine

    Science.gov (United States)

    Yang, Peng; Chen, Hui; Liu, Yingwen

    2017-06-01

    In this paper, a two-dimensional axisymmetric model of a thermoacoustic Stirling engine with a short tube where the cross section narrows has been developed. The transient streamlines and vortex formation through short tubes with different diameters in oscillatory flow have been investigated visually by computational fluid dynamics. Three dimensionless parameters, Reynolds number (Re), Keulegan-Carpenter number (KC), and Womersley number (Wo), are used to describe the flow regime and vortex characteristic throughout the short tube. High Re and Wo numbers indicate that the oscillatory flow develops into the turbulent flow through the short tube. The KC number has a direct effect on the transition of streamlines and the development of the vortex. For a small cross section where KC ≈ 1, streamlines rotate and the vortex forms at both sides of the short tube. The vortex stays in the main flow region, and intensity varies as streamlines are convected downstream. The velocity along the radius presents a Poiseuille profile within the influence of the vortex. For a large cross section where KC < 1, streamlines pass the short tube with little rotation and the vortex disappears in the main flow region and confines near the short tube. The velocity profile tends to be flat. The nonlinear effects including instantaneous pressure drop and power dissipation throughout the short tube are also discussed. It shows that the time averaged pressure drop is generated at the cost of power dissipation. Finally, the "effectiveness" is applied to evaluate the performance of the short tube. The results suggest that increasing the diameter of the short tube is in favor of reducing power dissipation, which is beneficial to improve "effectiveness."

  10. Microfluidic DNA microarrays in PMMA chips: streamlined fabrication via simultaneous DNA immobilization and bonding activation by brief UV exposure

    DEFF Research Database (Denmark)

    Sabourin, David; Petersen, J; Snakenborg, Detlef

    2010-01-01

    This report presents and describes a simple and scalable method for producing functional DNA microarrays within enclosed polymeric, PMMA, microfluidic devices. Brief (30 s) exposure to UV simultaneously immobilized poly(T)poly(C)-tagged DNA probes to the surface of unmodified PMMA and activated...... the surface for bonding below the glass transition temperature of the bulk PMMA. Functionality and validation of the enclosed PMMA microarrays was demonstrated as 18 patients were correctly genotyped for all eight mutation sites in the HBB gene interrogated. The fabrication process therefore produced probes...... with desired hybridization properties and sufficient bonding between PMMA layers to allow construction of microfluidic devices. The streamlined fabrication method is suited to the production of low-cost microfluidic microarray-based diagnostic devices and, as such, is equally applicable to the development...

  11. Response of small pitot tubes in gas-liquid flows

    International Nuclear Information System (INIS)

    Davis, M.R.

    1980-01-01

    The pressure rise experienced by a pitot tube immersed in a bubbly gas-liquid mixture flow exceeds that predicted by homogeneous flow analysis under conditions where the pitot is smaller than the mean bubble size. A systematic dependence of the deviation from homogeneous flow analysis exists, depending upon the mixture void fraction. A maximum effect is observed at a void fraction of 0.60, where the pressure rise was found to be 1.73 times the predicted stagnation pressure rise or 0.87 of the mixture momentum flux density. The magnitude of these effects is comparable with similar effects reported elsewhere for gas/solid mixture flow due to relative motion between phases in the vicinity of the sensing probe tip. (orig.)

  12. Flow characteristics in nuclear steam turbine blade passage

    International Nuclear Information System (INIS)

    Ahn, H.J.; Yoon, W.H.; Kwon, S.B.

    1995-01-01

    The rapid expansion of condensable gas such as moist air or steam gives rise to nonequilibrium condensation. As a result of irreversibility of condensation process in the nuclear steam turbine blade passage, the entropy of the flow increases, and the efficiency of the turbine decreases. In the present study, in order to investigate the flow characteristics of moist air in two-dimensional turbine blade passage which is made from the configuration of the last stage tip section of the actual nuclear steam turbine moving blade, the static pressures along both pressure and suction sides of blade are measured by static pressure taps and the distribution of Mach number on both sides of the blade are obtained by using the measured static pressure. Also, the flow field is visualized by a Schlieren system. From the experimental results, the effects of the stagnation temperature and specific humidity on the flow properties in the two dimensional steam turbine blade passage are clearly identified

  13. Flow visualization IV; Proceedings of the Fourth International Symposium, Ecole Nationale Superieure de Techniques Avancees, Paris, France, Aug. 26-29, 1986

    International Nuclear Information System (INIS)

    Veret, C.

    1987-01-01

    Papers are presented on optical techniques, speckle techniques, observation methods, image processing, boundary layers and separated flows, stratified flows and the mixing layer, vortices and wakes, jets, supersonic and hypersonic flows, the velocity field, two-phase flows, heat transfer, and engines. Specific attention is paid to applications including shear layer stability in axisymmetric backstep flows, visualization of the pulsating flow past aortic prostheses, and flow visualization by dye and by optical interferometry. Other topics include photochromic flow visualization in liquid-liquid two-phase flow, shear flow patterns analyzed by video systems, the visualization of longitudinal vortices in stagnation flows, and the development of the Karman vortex due to buoyant force in opposing flow

  14. Study on changes of hypothalamus-pituitary-target axis hormones in patients with insomnia of fire-symdrome due to the stagnation

    International Nuclear Information System (INIS)

    Chen Jianfei; Yan Songqin

    2007-01-01

    Objective: To study the changes of hypothalamus-pituitary-target axis hormones in patients with insomnia of fire-symdrom due to the stagnation of liver-qi. Methods: Serum thyrotropin-releasing hormone (TRH), thyroid stimulating hormone (TSH), growth hormone (GH), free thyroxine (FT 4 ), cortisol levels were measured with immunoradioassay (IMRA) and radioimmunoassay (RIA) in 30 patients with this type of insomnia and 30 controls. Results: The serum TSH levels were significantly lower and serum TRH, GH, cortisol FT 4 levels were significantly higher in the patients than those in controls (P<0.05 or P<0.01). Conclusion: This insomnia syndrome was closely related to the dysfunction of mpothalamus-pituitary-thyroid and adrenal axis. (authors)

  15. Dynamics of topological solitons, knotted streamlines, and transport of cargo in liquid crystals

    Science.gov (United States)

    Sohn, Hayley R. O.; Ackerman, Paul J.; Boyle, Timothy J.; Sheetah, Ghadah H.; Fornberg, Bengt; Smalyukh, Ivan I.

    2018-05-01

    Active colloids and liquid crystals are capable of locally converting the macroscopically supplied energy into directional motion and promise a host of new applications, ranging from drug delivery to cargo transport at the mesoscale. Here we uncover how topological solitons in liquid crystals can locally transform electric energy to translational motion and allow for the transport of cargo along directions dependent on frequency of the applied electric field. By combining polarized optical video microscopy and numerical modeling that reproduces both the equilibrium structures of solitons and their temporal evolution in applied fields, we uncover the physical underpinnings behind this reconfigurable motion and study how it depends on the structure and topology of solitons. We show that, unexpectedly, the directional motion of solitons with and without the cargo arises mainly from the asymmetry in rotational dynamics of molecular ordering in liquid crystal rather than from the asymmetry of fluid flows, as in conventional active soft matter systems.

  16. STREAMLINED APPROACH FOR ENVIRONMENTAL RESTORATION PLAN FOR CORRECTIVE ACTION UNIT 116: AREA 25 TEST CELL C FACILITY NEVADA TEST SITE, NEVADA

    International Nuclear Information System (INIS)

    2006-01-01

    This Streamlined Approach for Environmental Restoration Plan identifies the activities required for the closure of Corrective Action Unit 116, Area 25 Test Cell C Facility. The Test Cell C Facility is located in Area 25 of the Nevada Test Site approximately 25 miles northwest of Mercury, Nevada

  17. Tracer dispersion in planar multipole flows

    International Nuclear Information System (INIS)

    Koplik, J.; Redner, S.; Hinch, E.J.

    1994-01-01

    We study the motion of passive Brownian tracer particles in steady two-dimensional potential flows between sources and sinks. Our primary focus is understanding the long-time properties of the transit time probability distribution for the tracer to reach the sink p(t) and the influence of the flow geometry on this probability. A variety of illustrative case studies is considered. For radial potential flow in an annular region, competition between convection and diffusion leads to nonuniversal decay of the transit time probability. Dipolar and higher multipole flows are found to exhibit generic features, such as a power-law decay in p(t) with an exponent determined by the multipole moment, an exponential cutoff related to stagnation points, and a ''shoulder'' in p(t) that is related to reflection from the system boundaries. For spatially extended sinks, it is also shown that the spatial distribution of the collected tracer is independent of the overall magnitude of the flow field and that p(t) decays as a power law with a geometry-dependent exponent. Our results may offer the possibility of using tracer measurements to characterize the flow geometry of porous media

  18. Flow produced in a conical container by a rotating endwall

    International Nuclear Information System (INIS)

    Escudier, M.P.; O'Leary, J.; Poole, R.J.

    2007-01-01

    Numerical calculations have been carried out for flow in a truncated cone generated by rotation of one endwall. For both convergent (radius increasing with approach to the rotating endwall) and divergent geometries, vortex breakdown is suppressed beyond a certain angle of inclination of the sidewall. At the same time Moffat eddies of increasing strength and extent appear in the corner between the sidewall and the non-rotating endwall. For the divergent geometry, a zone of recirculation appears on the sidewall and eventually merges with the Moffat eddies. The flow phenomena identified from streamline patterns are consistent with the calculated variation of pressure around the periphery of the computational domain

  19. A visual study of radial inward choked flow of liquid nitrogen.

    Science.gov (United States)

    Hendricks, R. C.; Simoneau, R. J.; Hsu, Y. Y.

    1973-01-01

    Data and high speed movies were acquired on pressurized subcooled liquid nitrogen flowing radially inward through a 0.0076 cm gap. The stagnation pressure ranged from 0.7 to 4 MN/sq m. Steady radial inward choked flow appears equivalent to steady choked flow through axisymmetric nozzles. Transient choked flows through the radial gap are not uniform and the discharge pattern appears as nonuniform impinging jets. The critical mass flow rate data for the transient case appear different from those for the steady case. On the mass flow rate vs pressure map, the slope and separation of the isotherms appear to be less for transient than for steady radial choked flow.

  20. Change regularity of water quality parameters in leakage flow conditions and their relationship with iron release.

    Science.gov (United States)

    Liu, Jingqing; Shentu, Huabin; Chen, Huanyu; Ye, Ping; Xu, Bing; Zhang, Yifu; Bastani, Hamid; Peng, Hongxi; Chen, Lei; Zhang, Tuqiao

    2017-11-01

    The long-term stagnation in metal water supply pipes, usually caused by intermittent consumption patterns, will cause significant iron release and water quality deterioration, especially at the terminus of pipelines. Another common phenomenon at the terminus of pipelines is leakage, which is considered helpful by allowing seepage of low-quality drinking water resulting from long-term stagnation. In this study, the effect of laminar flow on alleviating water quality deterioration under different leakage conditions was investigated, and the potential thresholds of the flow rate, which can affect the iron release process, were discussed. Based on a galvanized pipe and ductile cast iron pipe pilot platform, which was established at the terminus of pipelines, this research was carried out by setting a series of leakage rate gradients to analyze the influence of different leakage flow rates on iron release, as well as the relationship with chemical and biological parameters. The results showed that the water quality parameters were obviously influenced by the change in flow velocity. Water quality was gradually improved with an increase in flow velocity, but its change regularity reflected a diversity under different flow rates (p water distribution system, when the bulk water was at the critical laminar flow velocity, the concentration of total iron, the quantity and rate of total iron release remain relatively in an ideal and safe situation. Copyright © 2017. Published by Elsevier Ltd.

  1. Oscillatory Stokes Flow Past a Slip Cylinder

    Science.gov (United States)

    Palaniappan, D.

    2013-11-01

    Two-dimensional transient slow viscous flow past a circular cylinder with Navier slip boundary conditions is considered in the limit of low-Reynolds number. The oscillatory Stokes flow problem around a cylinder is solved using the stream function method leading to an analytic solution in terms of modified Bessel functions of the second kind. The corresponding steady-state behavior yields the familiar paradoxical result first detected by Stokes. It is noted that the two key parameters, viz., the frequency λ, and the slip coefficient ξ have a significant impact on the flow field in the vicinity of the cylinder contour. In the limit of very low frequency, the flow is dominated by a term containing a well-known biharmonic function found by Stokes that has a singular behavior at infinity. Local streamlines for small times show interesting flow patterns. Attached eddies due to flow separation - observed in the no-slip case - either get detached or pushed away from the cylinder surface as ξ is varied. Computed asymptotic results predict that the flow exhibits inviscid behavior far away from the cylinder in the frequency range 0 < λ << 1 . Although the frequency of oscillations is finite, our exact solutions reveal fairly rapid transitions in the flow domain. Research Enhancement grant, TAMUCC.

  2. Streamlined vessels for speedboats: Macro modifications of shark skin design applications

    Science.gov (United States)

    Ibrahim, M. D.; Amran, S. N. A.; Zulkharnain, A.; Sunami, Y.

    2018-01-01

    Functional properties of shark denticles have caught the attention of engineers and scientist today due to the hydrodynamic effects of its skin surface roughness. The skin of a fast swimming shark reveals riblet structures that help to reduce skin friction drag, shear stresses, making its movement to be more efficient and faster. Inspired by the structure of the shark skin denticles, our team has conducted a study on alternative on improving the hydrodynamic design of marine vessels by applying the simplified version of shark skin skin denticles on the surface hull of the vessels. Models used for this study are constructed and computational fluid dynamic (CFD) simulations are then carried out to predict the effectiveness of the hydrodynamic effects of the biomimetic shark skins on those models. Interestingly, the numerical calculated results obtained shows that the presence of biomimetic shark skin implemented on the vessels give improvements in the maximum speed as well as reducing the drag force experience by the vessels. The pattern of the wave generated post cruising area behind the vessels can also be observed to reduce the wakes and eddies. Theoretically, reduction of drag force provides a more efficient vessel with a better cruising speed. To further improve on this study, the authors are now actively arranging an experimental procedure in order to verify the numerical results obtained by CFD. The experimental test will be carried out using an 8 metre flow channel provided by University Malaysia Sarawak, Malaysia.

  3. The role of radio pharmacological imaging in streamlining the drug development process

    International Nuclear Information System (INIS)

    Campbell, D. B.

    1997-01-01

    Radio imaging techniques have found a place in clinical diagnosis, but there has been a hesitancy to use this approach in drug development. This reluctance may have been due to the availability of ligands, the time and cost of synthesis and the number of centres and for many the benefits are not evident. The use in drug development is potentially large since tomography can measure drug levels, specific binding, blood flow and activity within the human body. In drug discovery, the synthesis of candidate drugs with specific binding properties are dependent on understanding the disease and using appropriate in vitro or animal models. Using small animal tomographs, these can be validated using radio imaging. Pharmacokinetics and metabolic problems, such as the distribution of inhaled gases, drug targeting into tumours of the brain or specific gastrointestinal absorption sites can be investigated within the human rather than relying on animals. The high specific activity allows low doses to be administered to man with limited safety studies permitting kinetic and metabolic studies to be undertaken early in development. Safety studies and ensuing toxicological endpoints in animals rely on histopathology for gross degenerative in physiological function. Where concern exists, radio imaging could detect early in situ changes in humans, for example hepatic toxicity, before they become hazardous. In clinical studies, the action of drugs can be measured directly at the effector site prior to undertaking longer studies, which is important for many diseases, but particularly for those such as Alzheimer's disease, where improvements may be slow or subtle

  4. CFD study of fluid flow changes with erosion

    Science.gov (United States)

    López, Alejandro; Stickland, Matthew T.; Dempster, William M.

    2018-06-01

    For the first time, a three dimensional mesh deformation algorithm is used to assess fluid flow changes with erosion. The validation case chosen is the Jet Impingement Test, which was thoroughly analysed in previous works by Hattori et al. (Kenichi Sugiyama and Harada, 2008), Gnanavelu et al. in (Gnanavelu et al., 2009, 2011), Lopez et al. in (Lopez et al., 2015) and Mackenzie et al. in (Mackenzie et al., 2015). Nguyen et al. (2014) showed the formation of a new stagnation area when the wear scar is deep enough by performing a three-dimensional scan of the wear scar after 30 min of jet impingement test. However, in the work developed here, this stagnation area was obtained solely by computational means. The procedure consisted of applying an erosion model in order to obtain a deformed geometry, which, due to the changes in the flow pattern lead to the formation of a new stagnation area. The results as well as the wear scar were compared to the results by Nguyen et al. (2014) showing the same trend. OpenFOAM® was the software chosen for the implementation of the deforming mesh algorithm as well as remeshing of the computational domain after deformation. Different techniques for mesh deformation and approaches to erosion modelling are discussed and a new methodology for erosion calculation including mesh deformation is developed. This new approach is independent of the erosion modelling approach, being applicable to both Eulerian and Lagrangian based equations for erosion calculation. Its different applications such as performance decay in machinery subjected to erosion as well as modelling of natural erosion processes are discussed here.

  5. Midstream streamlining: crude-oil document exchange would be faster with fewer errors

    Energy Technology Data Exchange (ETDEWEB)

    Roche, P.

    2001-11-01

    WellPoint Systems, a Calgary-based oil and gas software firm has designed an Internet-based crude-oil document exchange system, dubbed CDOX, that would see battery operators filling out production forecast forms on the systems they are using now, but instead of faxing the form to pipeline and terminal operators the operator could automatically transmit data over the Internet to the intended companies' computers. Unlike e-mail, the information would be put in place at the receiving end without human intervention. At the heart of the system is a digital hub that securely routes documents from one system to another. Each participating company only has to keep its own profile information up to date, instead of managing hundreds of customer e-mail addresses. The system would run on software provided by webMethods Inc., a Fairfax, Virginia-based B2B software provider. Documents will be in extensible markup language (XML) which is more flexible than HTML, allowing groups of users to create their own tags or extensions, for integrated information flows and automated business-to-business transactions. Advantages are lower cost due to automated loading; CDOX would eliminate the need for manual retyping of faxed data and the errors made during this process; pipeline operators could start analyzing the data immediately rather than waiting to have the data keyed into their systems. A one-year pilot project is now being organized by WellPoint Systems. The pilot project will include crude oil shippers and pipeline operators. WellPoint hopes that the monthly Form A battery operators' forecast will be moving on the system within three months. During the rest of the year pilot project seven other documents are planned to be added, including notice of shipment and shippers balance.

  6. Semiflexible polymer conformation, distribution and migration in microcapillary flows

    International Nuclear Information System (INIS)

    Chelakkot, Raghunath; Gompper, Gerhard; Winkler, Roland G

    2011-01-01

    The flow behavior of a semiflexible polymer in microchannels is studied using multiparticle collision dynamics, a particle-based hydrodynamic simulation technique. Conformations, distributions, and radial cross-streamline migration are investigated for various bending rigidities, with persistence lengths L p in the range 0.5 ≤ L p /L r ≤ 30. The flow behavior is governed by the competition between a hydrodynamic lift force and steric repulsion from the wall, which lead to migration away from the wall, and a locally varying flow induced orientation, which drives the polymer away from the channel center and towards the wall. The different dependences of these effects on the polymer bending rigidity and the flow velocity results in a complex dynamical behavior. However, a generic effect is the appearance of a maximum in the monomer and the center-of-mass distributions, which occurs at the channel center for small flow velocities, but moves off-center at higher velocities.

  7. Streamlined Approach for Environmental Restoration (SAFER) Plan for Corrective Action Unit 465: Hydronuclear Nevada National Security Site, Nevada, with ROTC 1, Revision 0

    Energy Technology Data Exchange (ETDEWEB)

    Patrick Matthews

    2011-11-01

    This Streamlined Approach for Environmental Restoration (SAFER) Plan addresses the actions needed to achieve closure for Corrective Action Unit (CAU) 465, Hydronuclear, identified in the Federal Facility Agreement and Consent Order (FFACO). Corrective Action Unit 465 comprises the following four corrective action sites (CASs) located in Areas 6 and 27 of the Nevada National Security Site: (1) 00-23-01, Hydronuclear Experiment; (2) 00-23-02, Hydronuclear Experiment; (3) 00-23-03, Hydronuclear Experiment; (4) 06-99-01, Hydronuclear. The sites will be investigated based on the data quality objectives (DQOs) developed on July 6, 2011, by representatives of the Nevada Division of Environmental Protection (NDEP) and the U.S. Department of Energy (DOE), National Nuclear Security Administration Nevada Site Office. The DQO process was used to identify and define the type, amount, and quality of data needed to determine and implement appropriate corrective actions for each CAS in CAU 465. For CAU 465, two potential release components have been identified. The subsurface release component includes potential releases of radiological and nonradiological contaminants from the subsurface hydronuclear experiments and disposal boreholes. The surface release component consists of other potential releases of radiological and nonradiological contaminants to surface soils that may have occurred during the pre- and post-test activities. This plan provides the methodology for collection of the necessary information for closing each CAS component. There is sufficient information and process knowledge from historical documentation, contaminant characteristics, existing regional and site groundwater models, and investigations of similar sites regarding the expected nature and extent of potential contaminants to recommend closure of CAU 465 using the SAFER process. For potential subsurface releases, flow and transport models will be developed to integrate existing data into a conservative

  8. Nozzle flow calculation for real gases

    International Nuclear Information System (INIS)

    Bier, K.; Ehrler, F.; Hartz, U.; Kissau, G.

    1977-01-01

    The flow of CHF 2 Cl vapor (refrigerant R 22) through a Laval nozzle of annular geometry has been investigated in the region near the saturation line with stagnation pressures up to 85 per cent of the critical pressure. Static pressure profiles measured along the nozzle axis were found in good agreement with profiles calculated for one-dimensional isentropic flow of the real gas the thermal properties of which were derived from an equation of state proposed previously by Rombusch. Minor deviations between measured and calculated static pressure curves occur in the supersonic part of the mozzle, especially when supersaturated states of the vapour are passed. These deviations can be attributed to uncertainties in the calculation of the enthalpy and to a small influence of the static pressure probe. An additional investigation was concerned with an approximate calculation of the nozzle flow of real gases. In this approximation the well known relations of ideal gas dynamics are applied, the ratio of specific heats for the ideal gas being replaced, however, by a suitably adapted isentropic exponent, which can be determined e.g. from measured values of the Laval pressure or of the mass flow. For pressure ratios p/po between 1 and approximately 0.1, corresponding to Mach numbers up to approximately 2.2, all the interesting properties of the investigated flow of CHF 2 Cl vapour are approximated within a few per cent. (orig.) [de

  9. Numerical Simulation of Polymer Injection in Turbulent Flow Past a Circular Cylinder

    KAUST Repository

    Richter, David; Shaqfeh, Eric S. G.; Iaccarino, Gianluca

    2011-01-01

    Using a code developed to compute high Reynolds number viscoelastic flows, polymer injection from the upstream stagnation point of a circular cylinder is modeled at Re = 3900. Polymer stresses are represented using the FENE-P constitutive equations. By increasing polymer injection rates within realistic ranges, significant near wake stabilization is observed. Rather than a turbulent detached shear layer giving way to a chaotic primary vortex (as seen in Newtonian flows at high Re), a much more coherent primary vortex is shed, which possesses an increased core pressure as well as a reduced level of turbulent energy. © 2011 American Society of Mechanical Engineers.

  10. Simultaneous measurements of temperature and density in air flows using UV laser spectroscopy

    Science.gov (United States)

    Fletcher, D. G.; Mckenzie, R. L.

    1991-01-01

    The simultaneous measurement of temperature and density using laser-induced fluorescence of oxygen in combination with Q-branch Raman scattering of nitrogen and oxygen is demonstrated in a low-speed air flow. The lowest density and temperature measured in the experiment correspond to the freestream values at Mach 5 in the Ames 3.5-Foot Hypersonic Wind Tunnel for stagnation conditions of 100 atm and 1000 K. The experimental results demonstrate the viability of the optical technique for measurements that support the study of compressible turbulence and the validation of numerical codes in supersonic and hypersonic wind tunnel flows.

  11. Numerical calculation of the main variables of the laminar flow around a circunferential square obstacle at the wall of a circular pipe

    International Nuclear Information System (INIS)

    Nogueira, A.C.R.

    1981-10-01

    The numerical calculation of the main variables of the laminar, incompressible, axissimmetric, steady flow around a circunferential square obstacle placed at the wall of a circular pipe, is done. The velocity profiles, the separating length and the shape of the separating streamline are compared with experimental available data and a good agreement is achieved. (E.G.) [pt

  12. Streamlined Approach for Environmental Restoration Plan for Corrective Action Unit 574: Neptune, Nevada National Security Site, Nevada

    Energy Technology Data Exchange (ETDEWEB)

    NSTec Environmental Restoration

    2011-08-31

    This Streamlined Approach for Environmental Restoration (SAFER) Plan identifies the activities required for closure of Corrective Action Unit (CAU) 574, Neptune. CAU 574 is included in the Federal Facility Agreement and Consent Order (FFACO) (1996 [as amended March 2010]) and consists of the following two Corrective Action Sites (CASs) located in Area 12 of the Nevada National Security Site: (1) CAS 12-23-10, U12c.03 Crater (Neptune); (2) CAS 12-45-01, U12e.05 Crater (Blanca). This plan provides the methodology for the field activities that will be performed to gather the necessary information for closure of the two CASs. There is sufficient information and process knowledge regarding the expected nature and extent of potential contaminants to recommend closure of CAU 574 using the SAFER process. Based on historical documentation, personnel interviews, site process knowledge, site visits, photographs, field screening, analytical results, the results of the data quality objective (DQO) process (Section 3.0), and an evaluation of corrective action alternatives (Appendix B), closure in place with administrative controls is the expected closure strategy for CAU 574. Additional information will be obtained by conducting a field investigation to verify and support the expected closure strategy and provide a defensible recommendation that no further corrective action is necessary. This will be presented in a Closure Report that will be prepared and submitted to the Nevada Division of Environmental Protection (NDEP) for review and approval.

  13. Streamlined Membrane Proteome Preparation for Shotgun Proteomics Analysis with Triton X-100 Cloud Point Extraction and Nanodiamond Solid Phase Extraction

    Directory of Open Access Journals (Sweden)

    Minh D. Pham

    2016-05-01

    Full Text Available While mass spectrometry (MS plays a key role in proteomics research, characterization of membrane proteins (MP by MS has been a challenging task because of the presence of a host of interfering chemicals in the hydrophobic protein extraction process, and the low protease digestion efficiency. We report a sample preparation protocol, two-phase separation with Triton X-100, induced by NaCl, with coomassie blue added for visualizing the detergent-rich phase, which streamlines MP preparation for SDS-PAGE analysis of intact MP and shot-gun proteomic analyses. MP solubilized in the detergent-rich milieu were then sequentially extracted and fractionated by surface-oxidized nanodiamond (ND at three pHs. The high MP affinity of ND enabled extensive washes for removal of salts, detergents, lipids, and other impurities to ensure uncompromised ensuing purposes, notably enhanced proteolytic digestion and down-stream mass spectrometric (MS analyses. Starting with a typical membranous cellular lysate fraction harvested with centrifugation/ultracentrifugation, MP purities of 70%, based on number (not weight of proteins identified by MS, was achieved; the weight-based purity can be expected to be much higher.

  14. The potential of high resolution melting analysis (hrma) to streamline, facilitate and enrich routine diagnostics in medical microbiology.

    Science.gov (United States)

    Ruskova, Lenka; Raclavsky, Vladislav

    2011-09-01

    Routine medical microbiology diagnostics relies on conventional cultivation followed by phenotypic techniques for identification of pathogenic bacteria and fungi. This is not only due to tradition and economy but also because it provides pure culture needed for antibiotic susceptibility testing. This review focuses on the potential of High Resolution Melting Analysis (HRMA) of double-stranded DNA for future routine medical microbiology. Search of MEDLINE database for publications showing the advantages of HRMA in routine medical microbiology for identification, strain typing and further characterization of pathogenic bacteria and fungi in particular. The results show increasing numbers of newly-developed and more tailor-made assays in this field. For microbiologists unfamiliar with technical aspects of HRMA, we also provide insight into the technique from the perspective of microbial characterization. We can anticipate that the routine availability of HRMA in medical microbiology laboratories will provide a strong stimulus to this field. This is already envisioned by the growing number of medical microbiology applications published recently. The speed, power, convenience and cost effectiveness of this technology virtually predestine that it will advance genetic characterization of microbes and streamline, facilitate and enrich diagnostics in routine medical microbiology without interfering with the proven advantages of conventional cultivation.

  15. Effects and mechanisms of Shaofu-Zhuyu decoction and its major bioactive component for Cold - Stagnation and Blood - Stasis primary dysmenorrhea rats.

    Science.gov (United States)

    Huang, Xiaochen; Su, Shulan; Duan, Jin-Ao; Sha, Xiuxiu; Zhu, Kavin Yue; Guo, Jianming; Yu, Li; Liu, Pei; Shang, Erxin; Qian, Dawei

    2016-06-20

    Traditional Chinese medicine (TCM) is used under the guidance of the theory of traditional Chinese medical sciences in clinical application. The Chinese herbal formula, Shaofu Zhuyu decoction (SFZYD), is considered as an effective prescription for treating Cold - Stagnation and Blood - Stasis (CSBS) primary dysmenorrhea. The previous studies showed the SFZYD exhibited significant anti-inflammation and analgesic effect. In this present study the metabolomics of CSBS primary dysmenorrhea diseased rats and the cytokine transcription in PHA stimulated-PBMC were investigated to explore the effects and mechanisms. Explore a valuable insight into the effects and mechanisms of SFZYD on Cold - Stagnation and Blood - Stasis primary dysmenorrhea rats. We established CSBS primary dysmenorrhea diseased rats according the clinical symptoms. A targeted tandem mass spectrometry (MS/MS)-based metabolomic platform was used to evaluate the metabolic profiling changes and the intervention effects by SFZYD. The PBMC cell was adopted to explore the mechanisms by analyzing the signaling pathway evaluated by expression of inflammatory cytokines, c-jun and c-fos and corresponding phosphorylation levels. Estradiol, oxytocin, progesterone, endothelin, β-endorphin and PGF2α were restored back to the normal level after the treatment of SFZYD. Total twenty-five metabolites (10 in plasma and 15 in urine), up-regulated or down-regulated, were identified. These identified biomarkers underpinning the metabolic pathway including pentose and glucuronate interconversions, steroid hormone biosynthesis, and glycerophospholipid metabolism are disturbed in model rats. Among these metabolites, twenty one potential biomarkers were regulated after SFZYD treated. The compound of paeoniflorin, a major bioactive compound in SFZYD, was proved to regulate the MAPK signaling pathway by inhibiting the expression of IL-1β, IL-2, IL-10, IL-12, TNFα, INFγ, c-jun and c-fos in PHA stimulated-PBMC. These findings

  16. Spin Transition in the Lower Mantle: Deep Learning and Pattern Recognition of Superplumes from the Mid-mantle and Mid-mantle Slab Stagnation

    Science.gov (United States)

    Yuen, D. A.; Shahnas, M. H.; De Hoop, M. V.; Pysklywec, R.

    2016-12-01

    The broad, slow seismic anomalies under Africa and Pacific cannot be explained without ambiguity. There is no well-established theory to explain the fast structures prevalent globally in seismic tomographic images that are commonly accepted to be the remnants of fossil slabs at different depths in the mantle. The spin transition from high spin to low spin in iron in ferropericlase and perovskite, two major constituents of the lower mantle can significantly impact their physical properties. We employ high resolution 2D-axisymmetric and 3D-spherical control volume models to reconcile the influence of the spin transition-induced anomalies in density, thermal expansivity, and bulk modulus in ferropericlase and perovskite on mantle dynamics. The model results reveal that the spin transition effects increase the mixing in the lower regions of mantle. Depending on the changes of bulk modulus associated with the spin transition, these effects may also cause both stagnation of slabs and rising plumes at mid-mantle depths ( 1600 km). The stagnation may be followed by downward or upward penetration of cold or hot mantle material, respectively, through an avalanche process. The size of these mid-mantle plumes reaches 1500 km across with a radial velocity reaching 20 cm/yr near the seismic transition zone and plume heads exceeding 2500 km across. We will employ a deep-learning algorithm to formulate this challenge as a classification problem where modelling/computation aids in the learning stage for detecting the particular patterns.The parameters based on which the convection models are developed are poorly constrained. There are uncertainties in initial conditions, heterogeneities and boundary conditions in the simulations, which are nonlinear. Thus it is difficult to reconstruct the past configuration over long time scales. In order to extract information and better understand the parameters in mantle convection, we employ deep learning algorithm to search for different

  17. Flow Visualization with Quantified Spatial and Temporal Errors Using Edge Maps

    KAUST Repository

    Bhatia, H.

    2012-09-01

    Robust analysis of vector fields has been established as an important tool for deriving insights from the complex systems these fields model. Traditional analysis and visualization techniques rely primarily on computing streamlines through numerical integration. The inherent numerical errors of such approaches are usually ignored, leading to inconsistencies that cause unreliable visualizations and can ultimately prevent in-depth analysis. We propose a new representation for vector fields on surfaces that replaces numerical integration through triangles with maps from the triangle boundaries to themselves. This representation, called edge maps, permits a concise description of flow behaviors and is equivalent to computing all possible streamlines at a user defined error threshold. Independent of this error streamlines computed using edge maps are guaranteed to be consistent up to floating point precision, enabling the stable extraction of features such as the topological skeleton. Furthermore, our representation explicitly stores spatial and temporal errors which we use to produce more informative visualizations. This work describes the construction of edge maps, the error quantification, and a refinement procedure to adhere to a user defined error bound. Finally, we introduce new visualizations using the additional information provided by edge maps to indicate the uncertainty involved in computing streamlines and topological structures. © 2012 IEEE.

  18. Flow Visualization with Quantified Spatial and Temporal Errors Using Edge Maps

    KAUST Repository

    Bhatia, H.; Jadhav, S.; Bremer, P.; Guoning Chen,; Levine, J. A.; Nonato, L. G.; Pascucci, V.

    2012-01-01

    Robust analysis of vector fields has been established as an important tool for deriving insights from the complex systems these fields model. Traditional analysis and visualization techniques rely primarily on computing streamlines through numerical integration. The inherent numerical errors of such approaches are usually ignored, leading to inconsistencies that cause unreliable visualizations and can ultimately prevent in-depth analysis. We propose a new representation for vector fields on surfaces that replaces numerical integration through triangles with maps from the triangle boundaries to themselves. This representation, called edge maps, permits a concise description of flow behaviors and is equivalent to computing all possible streamlines at a user defined error threshold. Independent of this error streamlines computed using edge maps are guaranteed to be consistent up to floating point precision, enabling the stable extraction of features such as the topological skeleton. Furthermore, our representation explicitly stores spatial and temporal errors which we use to produce more informative visualizations. This work describes the construction of edge maps, the error quantification, and a refinement procedure to adhere to a user defined error bound. Finally, we introduce new visualizations using the additional information provided by edge maps to indicate the uncertainty involved in computing streamlines and topological structures. © 2012 IEEE.

  19. Study on the inside gas flow visualization of oxygen sensor cover; Kashika ni yoru O2 sensor cover nai no gas nagare hyoka

    Energy Technology Data Exchange (ETDEWEB)

    Hocho, S; Mitsuishi, Y; Inagaki, M [Nippon Soken, Inc., Tokyo (Japan); Hamaguchi, S; Mizusawa, K [Toyota Motor Corp., Aichi (Japan)

    1997-10-01

    In order to make clear the difference of the response time between the oxygen sensors with different protection covers, we visualized gas flow inside of sensor covers by means of two experimental methods: One is `Smoke Suspension Method` using liquid paraffin vapor as the smoke. With smoke suspension method, we detected the streamlines inside of the covers. The other is `Color Reaction Method` using the reaction of phenolphthalein and NH3 gas. With color reaction method, we confirmed the streamline inside of the cover and furthermore detected the difference of the response time of each sensor. 3 refs., 7 figs., 1 tab.

  20. CFD Prediction on the Pressure Distribution and Streamlines around an Isolated Single-Storey House Considering the Effect of Topographic Characteristics

    Science.gov (United States)

    Abdullah, J.; Zaini, S. S.; Aziz, M. S. A.; Majid, T. A.; Deraman, S. N. C.; Yahya, W. N. W.

    2018-04-01

    Single-storey houses are classified as low rise building and vulnerable to damages under windstorm event. This study was carried out with the aim to investigate the pressure distribution and streamlines around an isolated house by considering the effect of terrain characteristics. The topographic features such as flat, depression, ridge, and valley, are considered in this study. This simulation were analysed with Ansys FLUENT 14.0 software package. The result showed the topography characteristics influence the value of pressure coefficient and streamlines especially when the house was located at ridge terrain. The findings strongly suggested that wind analysis should include all topographic features in the analysis in order to establish the true wind force exerted on any structure.

  1. Flow Control in a Compact Inlet

    Science.gov (United States)

    Vaccaro, John C.

    2011-12-01

    secondary flow structures. Unlike the baseline, these secondary flow structures produced downwash along the centerline. The formation of such structures was caused by the core flow stagnating on the lower surface near the aerodynamic interface plane. Using the two-dimensional steady jet resulted in an increase in the spanwise flow within the inlet and a reduction in the energy content of the 350 Hz shedding frequency. Unsteady forcing did not show much improvement over steady forcing for this configuration. A spanwise varying control jet and a hybrid Coanda jet / vortex generator jets were tested to reduce the three-dimensionality of the flow field. It was found that anytime the flow control method suppressed separation along the centerline, counter-rotating vortices existed in the lower corners of the aerodynamic interface plane.

  2. Experimental analysis of flow structure in contra-rotating axial flow pump designed with different rotational speed concept

    Science.gov (United States)

    Cao, Linlin; Watanabe, Satoshi; Imanishi, Toshiki; Yoshimura, Hiroaki; Furukawa, Akinori

    2013-08-01

    As a high specific speed pump, the contra-rotating axial flow pump distinguishes itself in a rear rotor rotating in the opposite direction of the front rotor, which remarkably contributes to the energy conversion, the reduction of the pump size, better hydraulic and cavitation performances. However, with two rotors rotating reversely, the significant interaction between blade rows was observed in our prototype contra-rotating rotors, which highly affected the pump performance compared with the conventional axial flow pumps. Consequently, a new type of rear rotor was designed by the rotational speed optimization methodology with some additional considerations, aiming at better cavitation performance, the reduction of blade rows interaction and the secondary flow suppression. The new rear rotor showed a satisfactory performance at the design flow rate but an unfavorable positive slope of the head — flow rate curve in the partial flow rate range less than 40% of the design flow rate, which should be avoided for the reliability of pump-pipe systems. In the present research, to understand the internal flow field of new rear rotor and its relation to the performances at the partial flow rates, the velocity distributions at the inlets and outlets of the rotors are firstly investigated. Then, the boundary layer flows on rotor surfaces, which clearly reflect the secondary flow inside the rotors, are analyzed through the limiting streamline observations using the multi-color oil-film method. Finally, the unsteady numerical simulations are carried out to understand the complicated internal flow structures in the rotors.

  3. Rotational flow in tapered slab rocket motors

    Science.gov (United States)

    Saad, Tony; Sams, Oliver C.; Majdalani, Joseph

    2006-10-01

    Internal flow modeling is a requisite for obtaining critical parameters in the design and fabrication of modern solid rocket motors. In this work, the analytical formulation of internal flows particular to motors with tapered sidewalls is pursued. The analysis employs the vorticity-streamfunction approach to treat this problem assuming steady, incompressible, inviscid, and nonreactive flow conditions. The resulting solution is rotational following the analyses presented by Culick for a cylindrical motor. In an extension to Culick's work, Clayton has recently managed to incorporate the effect of tapered walls. Here, an approach similar to that of Clayton is applied to a slab motor in which the chamber is modeled as a rectangular channel with tapered sidewalls. The solutions are shown to be reducible, at leading order, to Taylor's inviscid profile in a porous channel. The analysis also captures the generation of vorticity at the surface of the propellant and its transport along the streamlines. It is from the axial pressure gradient that the proper form of the vorticity is ascertained. Regular perturbations are then used to solve the vorticity equation that prescribes the mean flow motion. Subsequently, numerical simulations via a finite volume solver are carried out to gain further confidence in the analytical approximations. In illustrating the effects of the taper on flow conditions, comparisons of total pressure and velocity profiles in tapered and nontapered chambers are entertained. Finally, a comparison with the axisymmetric flow analog is presented.

  4. Flow Structure and Surface Topology on a UCAV Planform

    Science.gov (United States)

    Elkhoury, Michel; Yavuz, Metin; Rockwell, Donald

    2003-11-01

    Flow past a X-45 UCAV planform involves the complex generation and interaction of vortices, their breakdown and occurrence of surface separation and stall. A cinema technique of high-image-density particle image velocimetry, in conjunction with dye visualization, allows characterization of the time-averaged and instantaneous states of the flow, in terms of critical points of the near-surface streamlines. These features are related to patterns of surface normal vorticity and velocity fluctuation. Spectral analysis of the naturally occurring unsteadiness of the flow allows definition of the most effective frequencies for small-amplitude perturbation of the wing, which leads to substantial alterations of the aforementioned patterns of flow structure and topology adjacent to the surface.

  5. Mixed convection boundary-layer flow from a horizontal circular cylinder with a constant surface heat flux

    Energy Technology Data Exchange (ETDEWEB)

    Nazar, R.; Amin, N. [Department of Mathematics, Universiti Teknologi Malaysia, 81310 Johor Bahru, Johor (Malaysia); Pop, I. [Faculty of Mathematics, University of Cluj, R-3400 Cluj, CP 253 (Romania)

    2004-02-01

    The laminar mixed convection boundary-layer flow of a viscous and incompressible fluid past a horizontal circular cylinder, which is maintained at a constant heat flux and is placed in a stream flowing vertically upward has been theoretically studied in this paper. The solutions for the flow and heat transfer characteristics are evaluated numerically for different values of the mixed convection parameter {lambda} with the Prandtl number Pr = 1 and 7, respectively. It is found, as for the case of a heated or cooled cylinder, considered by Merkin [5], that assisting flow delays separation of the boundary-layer and can, if the assisting flow is strong enough, suppress it completely. The opposing flow, on the other side, brings the separation point nearer to the lower stagnation point and for sufficiently strong opposing flows there will not be a boundary-layer on the cylinder. (orig.)

  6. Can streamlined multi-criteria decision analysis be used to implement shared decision making for colorectal cancer screening?

    Science.gov (United States)

    Dolan, James G.; Boohaker, Emily; Allison, Jeroan; Imperiale, Thomas F.

    2013-01-01

    Background Current US colorectal cancer screening guidelines that call for shared decision making regarding the choice among several recommended screening options are difficult to implement. Multi-criteria decision analysis (MCDA) is an established methodology well suited for supporting shared decision making. Our study goal was to determine if a streamlined form of MCDA using rank order based judgments can accurately assess patients’ colorectal cancer screening priorities. Methods We converted priorities for four decision criteria and three sub-criteria regarding colorectal cancer screening obtained from 484 average risk patients using the Analytic Hierarchy Process (AHP) in a prior study into rank order-based priorities using rank order centroids. We compared the two sets of priorities using Spearman rank correlation and non-parametric Bland-Altman limits of agreement analysis. We assessed the differential impact of using the rank order-based versus the AHP-based priorities on the results of a full MCDA comparing three currently recommended colorectal cancer screening strategies. Generalizability of the results was assessed using Monte Carlo simulation. Results Correlations between the two sets of priorities for the seven criteria ranged from 0.55 to 0.92. The proportions of absolute differences between rank order-based and AHP-based priorities that were more than ± 0.15 ranged from 1% to 16%. Differences in the full MCDA results were minimal and the relative rankings of the three screening options were identical more than 88% of the time. The Monte Carlo simulation results were similar. Conclusion Rank order-based MCDA could be a simple, practical way to guide individual decisions and assess population decision priorities regarding colorectal cancer screening strategies. Additional research is warranted to further explore the use of these methods for promoting shared decision making. PMID:24300851

  7. Streamlined Approach for Environmental Restoration Plan for Corrective Action Unit 408: Bomblet Target Area, Tonopah Test Range, Nevada

    International Nuclear Information System (INIS)

    NSTec Environmental Management

    2006-01-01

    This Streamlined Approach for Environmental Restoration Plan provides the details for the closure of Corrective Action Unit (CAU) 408, Bomblet Target Area. CAU 408 is located at the Tonopah Test Range and is currently listed in Appendix III of the Federal Facility Agreement and Consent Order of 1996. One Corrective Action Site (CAS) is included in CAU 408: (lg b ullet) CAS TA-55-002-TAB2, Bomblet Target Areas Based on historical documentation, personnel interviews, process knowledge, site visits, aerial photography, multispectral data, preliminary geophysical surveys, and the results of data quality objectives process (Section 3.0), clean closure will be implemented for CAU 408. CAU 408 closure activities will consist of identification and clearance of bomblet target areas, identification and removal of depleted uranium (DU) fragments on South Antelope Lake, and collection of verification samples. Any soil containing contaminants at concentrations above the action levels will be excavated and transported to an appropriate disposal facility. Based on existing information, contaminants of potential concern at CAU 408 include explosives. In addition, at South Antelope Lake, bomblets containing DU were tested. None of these contaminants is expected to be present in the soil at concentrations above the action levels; however, this will be determined by radiological surveys and verification sample results. The corrective action investigation and closure activities have been planned to include data collection and hold points throughout the process. Hold points are designed to allow decision makers to review the existing data and decide which of the available options are most suitable. Hold points include the review of radiological, geophysical, and analytical data and field observations

  8. Streamlined Approach for Environmental Restoration Plan for Corrective Action Unit 107: Low Impact Soil Sites, Nevada Test Site, Nevada

    International Nuclear Information System (INIS)

    2008-01-01

    This Streamlined Approach for Environmental Restoration Plan covers activities associated with Corrective Action Unit (CAU) 107 of the Federal Facility Agreement and Consent Order (FFACO, 1996 (as amended February 2008)). CAU 107 consists of the following Corrective Action Sites (CASs) located in Areas 1, 2, 3, 4, 5, 9, 10, and 18 of the Nevada Test Site. (1) CAS 01-23-02, Atmospheric Test Site - High Alt; (2) CAS 02-23-02, Contaminated Areas (2); (3) CAS 02-23-03, Contaminated Berm; (4) CAS 02-23-10, Gourd-Amber Contamination Area; (5) CAS 02-23-11, Sappho Contamination Area; (6) CAS 02-23-12, Scuttle Contamination Area; (7) CAS 03-23-24, Seaweed B Contamination Area; (8) CAS 03-23-27, Adze Contamination Area; (9) CAS 03-23-28, Manzanas Contamination Area; (10) CAS 03-23-29, Truchas-Chamisal Contamination Area; (11) CAS 04-23-02, Atmospheric Test Site T4-a; (12) CAS 05-23-06, Atmospheric Test Site; (13) CAS 09-23-06, Mound of Contaminated Soil; (14) CAS 10-23-04, Atmospheric Test Site M-10; and (15) CAS 18-23-02, U-18d Crater (Sulky). Based on historical documentation, personnel interviews, site process knowledge, site visits, photographs, engineering drawings, field screening, analytical results, and the results of data quality objectives process (Section 3.0), closure in place with administrative controls or no further action will be implemented for CAU 107. CAU 107 closure activities will consist of verifying that the current postings required under Title 10 Code of Federal Regulations (CFR) Part 835 are in place and implementing use restrictions (URs) at two sites, CAS 03-23-29 and CAS 18-23-02. The current radiological postings combined with the URs are adequate administrative controls to limit site access and worker dose

  9. Streamlined Approach for Environmental Restoration Plan for Corrective Action Unit 107: Low Impact Soil Sites, Nevada Test Site, Nevada

    International Nuclear Information System (INIS)

    2009-01-01

    This Streamlined Approach for Environmental Restoration Plan covers activities associated with Corrective Action Unit (CAU) 107 of the Federal Facility Agreement and Consent Order (1996 (as amended February 2008)). CAU 107 consists of the following Corrective Action Sites (CASs) located in Areas 1, 2, 3, 4, 5, 9, 10, and 18 of the Nevada Test Site. (sm b ullet) CAS 01-23-02, Atmospheric Test Site - High Alt(sm b ullet) CAS 02-23-02, Contaminated Areas (2)(sm b ullet) CAS 02-23-03, Contaminated Berm(sm b ullet) CAS 02-23-10, Gourd-Amber Contamination Area(sm b ullet) CAS 02-23-11, Sappho Contamination Area(sm b ullet) CAS 02-23-12, Scuttle Contamination Area(sm b ullet) CAS 03-23-24, Seaweed B Contamination Area(sm b ullet) CAS 03-23-27, Adze Contamination Area(sm b ullet) CAS 03-23-28, Manzanas Contamination Area(sm b ullet) CAS 03-23-29, Truchas-Chamisal Contamination Area(sm b ullet) CAS 04-23-02, Atmospheric Test Site T4-a(sm b ullet) CAS 05-23-06, Atmospheric Test Site(sm b ullet) CAS 09-23-06, Mound of Contaminated Soil(sm b ullet) CAS 10-23-04, Atmospheric Test Site M-10(sm b ullet) CAS 18-23-02, U-18d Crater (Sulky) Based on historical documentation, personnel interviews, site process knowledge, site visits, photographs, engineering drawings, field screening, analytical results, and the results of data quality objectives process (Section 3.0), closure in place with administrative controls or no further action will be implemented for CAU 107.

  10. Flow and Heat Transfer Characteristics of Turbulent Gas Flow in Microtube with Constant Heat Flux

    International Nuclear Information System (INIS)

    Hong, Chungpyo; Matsushita, Shinichi; Ueno, Ichiro; Asako, Yutaka

    2012-01-01

    Local friction factors for turbulent gas flows in circular microtubes with constant wall heat flux were obtained numerically. The numerical methodology is based on arbitrary-Lagrangian-Eulerian method to solve two-dimensional compressible momentum and energy equations. The Lam-Bremhorst's Low-Reynolds number turbulence model was employed to calculate eddy viscosity coefficient and turbulence energy. The simulations were performed for a wide flow range of Reynolds numbers and Mach numbers with different constant wall heat fluxes. The stagnation pressure was chosen in such a way that the outlet Mach number ranged from 0.07 to 1.0. Both Darcy friction factor and Fanning friction factor were locally obtained. The result shows that the obtained both friction factors were evaluated as a function of Reynolds number on the Moody chart. The values of Darcy friction factor differ from Blasius correlation due to the compressibility effects but the values of Fanning friction factor almost coincide with Blasius correlation. The wall heat flux varied from 100 to 10000 W/m 2 . The wall and bulk temperatures with positive heat flux are compared with those of incompressible flow. The result shows that the Nusselt number of turbulent gas flow is different from that of incompressible flow.

  11. Mechanism of flow reversal during solidification of an anomalous liquid

    Science.gov (United States)

    Kumar, Virkeshwar; Kumawat, Mitesh; Srivastava, Atul; Karagadde, Shyamprasad

    2017-12-01

    In a wide variety of fluidic systems involving thermal and compositional gradients, local density changes lead to the onset of natural convection that influences the process itself, for example, during phase-change phenomena and magmatic flows. Accurate knowledge of the flow characteristics is essential to quantify the impact of the flow of the processes. In this work, the first-ever demonstration of flow reversal during bottom-up solidification of water using full-field thermal and flow measurements and its direct impact on the solidifying interface is presented. Based on prior optical interferometric measurements of full-field temperature distribution in water during solidification, we use the particle image velocimetry technique to quantify and reveal the changing natural convection pattern arising solely due to the density anomaly of water between 0 °C and 4 °C. The independently captured thermal and flow fields show striking similarities and clearly elucidate the plausible mechanism explaining the formation of a curved interface at the stagnation point and the subsequent reversal of flow direction due to a changed interface morphology. A control volume analysis is further presented to estimate the energy invested in the formation of a perturbation and the resulting flip in the flow direction caused by this perturbation.

  12. Analysis Streamlining in ATLAS

    CERN Document Server

    Heinrich, Lukas; The ATLAS collaboration

    2018-01-01

    We present recent work within the ATLAS collaboration centrally provide tools to facilitate analysis management and highly automated container-based analysis execution in order to both enable non-experts to benefit from these best practices as well as the collaboration to track and re-execute analyses indpendently, e.g. during their review phase. Through integration with the ATLAS GLANCE system, users can request a pre-configured, but customizable version control setup, including continuous integration for automated build and testing as well as continuous Linux Container image building for software preservation purposes. As analyses typically require many individual steps, analysis workflow pipelines can then be defined using such images and the yadage workflow description language. The integration into the workflow exection service REANA allows the interactive or automated reproduction of the main analysis results by orchestrating a large number of container jobs using the Kubernetes. For long-term archival,...

  13. Streamlining the Hiring Process

    Science.gov (United States)

    DePrater, Karen

    2011-01-01

    Historically, education employees have been hired after a process that consists of these steps: Determining the need for a position, posting the vacancy, paper-screening applications, an interview with a panel or committee, background check, reference calling, and finally the selection of a candidate. This is a very time-consuming and costly…

  14. Streamline topology of steady axisymmetric vortex breakdown in a cylinder with co- and counter-rotating end-covers

    DEFF Research Database (Denmark)

    Brøns, Morten; Voigt, Lars Peter Køllgaard; Sørensen, Jens Nørkær

    1998-01-01

    Using a combination of bifurcation theory for two-dimensional dynamical systems and numerical simulations, we systematically determine the possible flow topologies of the steady vortex breakdown in axisymmetric flow in a cylindrical container with rotating end-covers. For fixed values...

  15. Streamline topology of steady axisymmetric vortex breakdown in a cylinder with co- and counter-rotating end-covers

    DEFF Research Database (Denmark)

    Brøns, Morten; Voigt, Lars Peter Kølgaard; Sørensen, Jens Nørkær

    1999-01-01

    Using a combination of bifurcation theory for two-dimensional dynamical systems and numerical simulations, we systematically determine the possible flow topologies of the steady vortex breakdown in axisymmetric flow in a cylindrical container with rotating end-covers. For fixed values of the ratio...

  16. A continuum model for pressure-flow relationship in human pulmonary circulation.

    Science.gov (United States)

    Huang, Wei; Zhou, Qinlian; Gao, Jian; Yen, R T

    2011-06-01

    A continuum model was introduced to analyze the pressure-flow relationship for steady flow in human pulmonary circulation. The continuum approach was based on the principles of continuum mechanics in conjunction with detailed measurement of vascular geometry, vascular elasticity and blood rheology. The pulmonary arteries and veins were considered as elastic tubes and the "fifth-power law" was used to describe the pressure-flow relationship. For pulmonary capillaries, the "sheet-flow" theory was employed and the pressure-flow relationship was represented by the "fourth-power law". In this paper, the pressure-flow relationship for the whole pulmonary circulation and the longitudinal pressure distribution along the streamlines were studied. Our computed data showed general agreement with the experimental data for the normal subjects and the patients with mitral stenosis and chronic bronchitis in the literature. In conclusion, our continuum model can be used to predict the changes of steady flow in human pulmonary circulation.

  17. Magnetohydrodynamic Ekman layers with field-aligned flow

    Energy Technology Data Exchange (ETDEWEB)

    Nunez, Manuel, E-mail: mnjmhd@am.uva.es [Departamento de Analisis Matematico, Universidad de Valladolid, 47005 Valladolid (Spain)

    2011-05-01

    The Ekman layer in a conducting fluid with constant angular velocity, provided with a magnetic field aligned with the flow, is studied here. The existence of solutions to the magnetohydrodynamic linearized equations depends on the balance between viscosity and resistivity, on the one hand, and the angular and Alfven velocities, on the other. In most cases, exponentially decreasing solutions exist, although their longitudinal oscillations do not need to be periodic. One of the instances without a solution is explained by the presence of Alfven waves traveling backwards along the streamlines.

  18. Lagrangian structures in time-periodic vortical flows

    Directory of Open Access Journals (Sweden)

    S. V. Kostrykin

    2006-01-01

    Full Text Available The Lagrangian trajectories of fluid particles are experimentally studied in an oscillating four-vortex velocity field. The oscillations occur due to a loss of stability of a steady flow and result in a regular reclosure of streamlines between the vortices of the same sign. The Eulerian velocity field is visualized by tracer displacements over a short time period. The obtained data on tracer motions during a number of oscillation periods show that the Lagrangian trajectories form quasi-regular structures. The destruction of these structures is determined by two characteristic time scales: the tracers are redistributed sufficiently fast between the vortices of the same sign and much more slowly transported into the vortices of opposite sign. The observed behavior of the Lagrangian trajectories is quantitatively reproduced in a new numerical experiment with two-dimensional model of the velocity field with a small number of spatial harmonics. A qualitative interpretation of phenomena observed on the basis of the theory of adiabatic chaos in the Hamiltonian systems is given. The Lagrangian trajectories are numerically simulated under varying flow parameters. It is shown that the spatial-temporal characteristics of the Lagrangian structures depend on the properties of temporal change in the streamlines topology and on the adiabatic parameter corresponding to the flow. The condition for the occurrence of traps (the regions where the Lagrangian particles reside for a long time is obtained.

  19. Application of Potential Theory to Steady Flow Past Two Cylinders in Tandem Arrangement

    Directory of Open Access Journals (Sweden)

    Yangyang Gao

    2014-01-01

    Full Text Available The wake flow patterns associated with flow past a cylinder and a cylinder-pair in tandem configuration are revisited, compared, and evaluated with respect to the streamline patterns generated based on potential flow theory and superposition of various potential flow elements. The wakes, which are vortex shedding in the lee of the cylinder(s, are reproduced by placing pairs of equal but opposite circulation elements in the potential flow field. The strength of the circulation elements determines the size of the vortices produced. The streamline patterns of flow past a pair of unequal cylinders in tandem configuration provide an indirect means to establish the threshold condition for the wake transition from that of a single bluff body to alternating reattachment behavior. This threshold condition is found to be a function of the diameter ratio, d/D (diameters d and D, d≤D , spacing ratio, L/D (centre-to-centre distance, L, to cylinder diameter, D, and equivalent incident flow speed, U. A unique functional relationship f (L/D, d/D, U of this threshold condition is established.

  20. Analysis of the test results for the two-phase critical flow with non-condensible gas

    International Nuclear Information System (INIS)

    Chang, S. K.; Chung, C. H.; Park, H. S.; Min, K. H.; Choi, N. H.; Kim, C. H.; Lee, S. H.; Kim, H. C.; Chang, M. H.

    2002-07-01

    The two-phase critical flow test was performed for simulating the pipe break accident of SMART reactor. The requirements of the critical flow test are 7∼20mm pipe break dia., 7∼12MPa stagnation pressure, 0∼60 .deg. C subcooling degree and 0∼0.5kg/s N 2 gas flow rate. The test section is sharp edged pipe type which has the dimension of I.D.=20, L=300mm and I.D.=10.9, L=1000mm. The test conditions are 4, 7, 10 MPa at stagnation pressure, 0, 20, 50 .deg. C of subcooling degree and 0.028∼0.39 kg/s of N 2 injection gas flowrate. The measured data at test section and other components in terms of pressure, temperature and flowrate were collected in DAS computer with maintaining the steady state conditions at least 60 seconds. From the test results, the critical characteristics of the break pipe were analysed and verified the capacity of the test facility. For the verification of the Modified Henry-Fauske model which can predict the two-phase critical flow with non-condensible gas, the code simulation using MARS which contains the option of the Modified Henry -Fauske model was performed. The simulation results of steady-state two-phase critical flow experiments show that they agree with the measured critical flow rates within 6% root-mean-square error

  1. One stop or full stop? The continuing challenges for researchers despite the new streamlined NHS research governance process

    Directory of Open Access Journals (Sweden)

    France Emma F

    2010-05-01

    Full Text Available Abstract Background Obtaining the necessary approvals and permission for clinical research requires successful negotiation of the ethical and R&D layers of the NHS. Differences in structure and governance frameworks feature between the constituent nations of the UK (England, Scotland, Wales and Northern Ireland, which adds complexity to cross-national studies. Difficulties in carrying out research in the NHS in the UK due to bureaucratic and time-consuming governance processes have led to the development of a new system of application and co-ordination from 2009. This paper illustrates how this new system fails to be consistent and streamlined and is unlikely to become so unless changes are made to the implementation and management of the governance processes. Methods We present a case study of the research governance process at the survey stage of an investigation into the use, preferences and need for information by people making choices or decisions about health care. The method involved home-based, face-to-face interviewing in a questionnaire survey in relation to decisions about lymphoma treatment, Down's syndrome screening in pregnancy, and caring for people with dementia. Results Our experience of the ethics stage was very positive, noting an efficient process of application and a speedy decision, both in relation to the initial application and to subsequent substantial amendments. By contrast, the R&D stages were very slow, most with unexplained delays, but some offering contradictory advice and exhibiting a lack of clear guidance and training for NHS staff. The R&D arrangements in Scotland were far quicker and more likely to be successful than in England. Overall, the delays were so severe that substantial parts of the research could not be delivered as planned within the funding timescale. Conclusions If high-quality research in the NHS, particularly in England, is to be delivered in a timely and cost-effective way, R&D processes for

  2. One stop or full stop? The continuing challenges for researchers despite the new streamlined NHS research governance process.

    Science.gov (United States)

    Thompson, Andrew G H; France, Emma F

    2010-05-13

    Obtaining the necessary approvals and permission for clinical research requires successful negotiation of the ethical and R&D layers of the NHS. Differences in structure and governance frameworks feature between the constituent nations of the UK (England, Scotland, Wales and Northern Ireland), which adds complexity to cross-national studies. Difficulties in carrying out research in the NHS in the UK due to bureaucratic and time-consuming governance processes have led to the development of a new system of application and co-ordination from 2009. This paper illustrates how this new system fails to be consistent and streamlined and is unlikely to become so unless changes are made to the implementation and management of the governance processes. We present a case study of the research governance process at the survey stage of an investigation into the use, preferences and need for information by people making choices or decisions about health care. The method involved home-based, face-to-face interviewing in a questionnaire survey in relation to decisions about lymphoma treatment, Down's syndrome screening in pregnancy, and caring for people with dementia. Our experience of the ethics stage was very positive, noting an efficient process of application and a speedy decision, both in relation to the initial application and to subsequent substantial amendments. By contrast, the R&D stages were very slow, most with unexplained delays, but some offering contradictory advice and exhibiting a lack of clear guidance and training for NHS staff. The R&D arrangements in Scotland were far quicker and more likely to be successful than in England. Overall, the delays were so severe that substantial parts of the research could not be delivered as planned within the funding timescale. If high-quality research in the NHS, particularly in England, is to be delivered in a timely and cost-effective way, R&D processes for gaining research governance approval need improvement. Attention is

  3. Streamlined Approach for Environmental Restoration Plan for Corrective Action Unit 398: Area 25 Spill Sites, Nevada Test Site, Nevada; TOPICAL

    International Nuclear Information System (INIS)

    K. B. Campbell

    2001-01-01

    This Streamlined Approach for Environmental Restoration (SAFER) plan addresses the activities necessary to close Corrective Action Unit (CAU) 398: Area 25 Spill Sites. CAU 398, located in Area 25 of the Nevada Test Site, is currently listed in Appendix III of the Federal Facility Agreement and Consent Order (FFACO) (FFACO, 1996), and consists of the following 13 Corrective Action Sites (CASs) (Figure 1): (1) CAS 25-44-01 , a fuel spill on soil that covers a concrete pad. The origins and use of the spill material are unknown, but the spill is suspected to be railroad bedding material. (2) CAS 25-44-02, a spill of liquid to the soil from leaking drums. (3) CAS 25-44-03, a spill of oil from two leaking drums onto a concrete pad and surrounding soil. (4) CAS 25-44-04, a spill from two tanks containing sulfuric acid and sodium hydroxide used for a water demineralization process. (5) CAS 25-25-02, a fuel or oil spill from leaking drums that were removed in 1992. (6) CAS 25-25-03, an oil spill adjacent to a tipped-over drum. The source of the drum is not listed, although it is noted that the drum was removed in 1991. (7) CAS 25-25-04, an area on the north side of the Engine-Maintenance, Assembly, and Disassembly (E-MAD) facility, where oils and cooling fluids from metal machining operations were poured directly onto the ground. (8) CAS 25-25-05, an area of oil and/or hydraulic fluid spills beneath the heavy equipment once stored there. (9) CAS 25-25-06, an area of diesel fuel staining beneath two generators that have since been removed. (10) CAS 25-25-07, an area of hydraulic oil spills associated with a tunnel-boring machine abandoned inside X-Tunnel. (11) CAS 25-25-08, an area of hydraulic fluid spills associated with a tunnel-boring machine abandoned inside Y-Tunnel. (12) CAS 25-25-16, a diesel fuel spill from an above-ground storage tank located near Building 3320 at Engine Test Stand-1 (ETS-1) that was removed in 1998. (13) CAS 25-25-17, a hydraulic oil spill

  4. Rotating flow

    CERN Document Server

    Childs, Peter R N

    2010-01-01

    Rotating flow is critically important across a wide range of scientific, engineering and product applications, providing design and modeling capability for diverse products such as jet engines, pumps and vacuum cleaners, as well as geophysical flows. Developed over the course of 20 years' research into rotating fluids and associated heat transfer at the University of Sussex Thermo-Fluid Mechanics Research Centre (TFMRC), Rotating Flow is an indispensable reference and resource for all those working within the gas turbine and rotating machinery industries. Traditional fluid and flow dynamics titles offer the essential background but generally include very sparse coverage of rotating flows-which is where this book comes in. Beginning with an accessible introduction to rotating flow, recognized expert Peter Childs takes you through fundamental equations, vorticity and vortices, rotating disc flow, flow around rotating cylinders and flow in rotating cavities, with an introduction to atmospheric and oceanic circul...

  5. Free-surface entrainment into a rimming flow containing surfactants

    Science.gov (United States)

    Thoroddsen, S. T.; Tan, Y.-K.

    2004-02-01

    We study experimentally the free-surface entrainment of tubes into a steady rimming flow formed inside a partially filled horizontally rotating cylinder. The liquid consists of a glycerin-water mixture containing surfactants (fatty acids). The phenomenon does not occur without the surfactants and the details are sensitive to their concentration. The entrainment of numerous closely spaced air tubes and/or surfactant columns can start intermittently along a two-dimensional stagnation line, but is usually associated with the appearance of an axially periodic vortex structure, the so-called shark teeth, which fixes the spanwise location of these tubes. The number of tubes is governed by the three-dimensional shape of the free surface, reducing from more than 10 to only two in each trough, as the rotation rate is increased. The tubes vary in diameter from 10-30 μm and can extend hundreds of diameters into the liquid layer before breaking up into a continuous stream of bubbles and/or drops. The tubes are driven through the stagnation line by the strong viscous shear and are stretched in the downstream direction. The entrainment starts when the Capillary number Ca=μωR/σ≃0.4.

  6. Flow visualization

    CERN Document Server

    Merzkirch, Wolfgang

    1974-01-01

    Flow Visualization describes the most widely used methods for visualizing flows. Flow visualization evaluates certain properties of a flow field directly accessible to visual perception. Organized into five chapters, this book first presents the methods that create a visible flow pattern that could be investigated by visual inspection, such as simple dye and density-sensitive visualization methods. It then deals with the application of electron beams and streaming birefringence. Optical methods for compressible flows, hydraulic analogy, and high-speed photography are discussed in other cha

  7. Credit Stagnation in Latin America

    OpenAIRE

    Adolfo Barajas; Roberto Steiner

    2002-01-01

    This study examines the recent marked slowdown in bank credit to the private sector in Latin America. Based on the study of eight countries (Argentina, Bolivia, Brazil, Chile, Colombia, Peru, Mexico, and Venezuela), the magnitude of the slowdown is documented, comparing it to historical behavior and to slowdown episodes in other regions of the world. Second, changes in bank balance sheets are examined to determine whether the credit slowdown is merely a reflection of a slowdown in bank deposi...

  8. Deleterious Thermal Effects due to Randomized Flow Paths in Pebble Bed, and Particle Bed Style Reactors

    Science.gov (United States)

    Moran, Robert P.

    2013-01-01

    Reactor fuel rod surface area that is perpendicular to coolant flow direction (+S) i.e. perpendicular to the P creates areas of coolant stagnation leading to increased coolant temperatures resulting in localized changes in fluid properties. Changes in coolant fluid properties caused by minor increases in temperature lead to localized reductions in coolant mass flow rates leading to localized thermal instabilities. Reductions in coolant mass flow rates result in further increases in local temperatures exacerbating changes to coolant fluid properties leading to localized thermal runaway. Unchecked localized thermal runaway leads to localized fuel melting. Reactor designs with randomized flow paths are vulnerable to localized thermal instabilities, localized thermal runaway, and localized fuel melting.

  9. Effect of microscale protrusions on local fluid flow and mass transport in the presence of forced convection

    Energy Technology Data Exchange (ETDEWEB)

    Matzen, Gehard W. [Univ. of California, Berkeley, CA (United States)

    1997-01-01

    Three-dimensional creeping flow around single, axisymmetric protrusions is studied numerically using the boundary-integral technique. Emphasis is placed upon cylindrical protrusions on plane walls for various height-to-radius (h-to-a) aspect ratios, but cones and sections of spheres protruding from plane walls are also briefly examined. The presented items include shear-stress distributions, shear-stress contours, extents of the fluid-flow disturbance, total forces and torques on the cylinders, streamlines, and skin-friction lines. Also included is a discussion of flow topology around axisymmetric geometries. No flow reversal is observed for cylindrical protrusions with aspect ratios greater than 2.4 to 2.6. At higher aspect ratios, the fluid tends to be swept around cylindrical protrusions with little vertical motion. At lower aspect ratios, the strength of the recirculation increases, and the recirculation region becomes wider in the transverse direction and narrower in the flow direction. Also, the recirculation pattern begins to resemble the closed streamline patterns in two-dimensional flow over square ridges. However, unlike two-dimensional flow, closed streamline patterns are not observed. For arbitrary axisymmetric geometries, the extent of the fluid-flow disturbance can be estimated with the total force that is exerted on the protrusion. When the same force is exerted on protrusions with different aspect ratios, the protrusion with the higher aspect ratio tends to have a greater disturbance in the flow direction and a smaller disturbance in the transverse direction. The total force exerted on cylindrical protrusions with rounded corners is only slightly lower than the total force exerted on cylindrical protrusions with sharp corners.

  10. Streamlined Total Synthesis of Trioxacarcins and Its Application to the Design, Synthesis, and Biological Evaluation of Analogues Thereof. Discovery of Simpler Designed and Potent Trioxacarcin Analogues.

    Science.gov (United States)

    Nicolaou, K C; Chen, Pengxi; Zhu, Shugao; Cai, Quan; Erande, Rohan D; Li, Ruofan; Sun, Hongbao; Pulukuri, Kiran Kumar; Rigol, Stephan; Aujay, Monette; Sandoval, Joseph; Gavrilyuk, Julia

    2017-11-01

    A streamlined total synthesis of the naturally occurring antitumor agents trioxacarcins is described, along with its application to the construction of a series of designed analogues of these complex natural products. Biological evaluation of the synthesized compounds revealed a number of highly potent, and yet structurally simpler, compounds that are effective against certain cancer cell lines, including a drug-resistant line. A novel one-step synthesis of anthraquinones and chloro anthraquinones from simple ketone precursors and phenylselenyl chloride is also described. The reported work, featuring novel chemistry and cascade reactions, has potential applications in cancer therapy, including targeted approaches as in antibody-drug conjugates.

  11. Investigating flow patterns in a channel with complex obstacles using the lattice Boltzmann method

    Energy Technology Data Exchange (ETDEWEB)

    Yojina, Jiraporn; Ngamsaad, Waipot; Nuttavut, Narin; Triampo, Darapond; Lenbury, Yongwimon; Sriyab, Somchai; Triampo, Wannapong [Faculty of Science, Mahidol University, Bangkok (Thailand); Kanthang, Paisan [Rajamangala University of Technology, Bangkok (Thailand)

    2010-10-15

    In this work, mesoscopic modeling via a computational lattice Boltzmann method (LBM) is used to investigate the flow pattern phenomena and the physical properties of the flow field around one and two square obstacles inside a two-dimensional channel with a fixed blockage ratio,{beta} =14 , centered inside a 2D channel, for a range of Reynolds numbers (Re) from 1 to 300. The simulation results show that flow patterns can initially exhibit laminar flow at low Re and then make a transition to periodic, unsteady, and, finally, turbulent flow as the Re get higher. Streamlines and velocity profiles and a vortex shedding pattern are observed. The Strouhal numbers are calculated to characterize the shedding frequency and flow dynamics. The effect of the layouts or configurations of the obstacles are also investigated, and the possible connection between the mixing process and the appropriate design of a chemical mixing system is discussed

  12. Theoretical and experimental investigation of the destruction of graphites in a flow of dissociated air

    Science.gov (United States)

    Bovina, T. A.; Zviagin, Y. V.; Markelov, N. V.; Chudetskiy, Y. V.

    1986-01-01

    A method is presented for calculating the heating and erosion of blunt bodies made of graphite in a high-enthalpy flow of dissociated air, assuming chemical equilibrium on the surface and taking account of the thermal effects of combustion and sublimation of graphite. The analysis involves the use of a finite difference scheme to solve an equation of unsteady heat conduction. Attention is given to the equilibrium vaporization of C, C2 and C3 molecules. The calculations agree well with experimental data for a wide range of temperatures and stagnation pressures.

  13. Flow regimes

    International Nuclear Information System (INIS)

    Kh'yuitt, G.

    1980-01-01

    An introduction into the problem of two-phase flows is presented. Flow regimes arizing in two-phase flows are described, and classification of these regimes is given. Structures of vertical and horizontal two-phase flows and a method of their identification using regime maps are considered. The limits of this method application are discussed. The flooding phenomena and phenomena of direction change (flow reversal) of the flow and interrelation of these phenomena as well as transitions from slug regime to churn one and from churn one to annular one in vertical flows are described. Problems of phase transitions and equilibrium are discussed. Flow regimes in tubes where evaporating liquid is running, are described [ru

  14. Flow-induced vibration and flow characteristics prediction for a sliding roller gate by two-dimensional unsteady CFD simulation

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Nak-Geun; Lee, Kye-Bock [Chungbuk National University, Cheongju (Korea, Republic of); Cho, Yong [Korea Water Resources Corporation, Daejeon (Korea, Republic of)

    2017-07-15

    Numerical analysis on the flow induced vibration and flow characteristics in the water gate has been carried out by 2-dimensional unsteady CFD simulation when sea water flows into the port in the river. Effect of gate opening on the frequency and the mean velocity and the vortex shedding under the water gate were studied. The streamlines were compared for various gate openings. To get the frequency spectrum, Fourier transform should be performed. Spectral analysis of the excitation force signals permitted identification of the main characteristics of the interaction process. The results show that the sources of disturbed frequency are the vortex shedding from under the water gate. As the gate opening ratio increases, the predicted vibration frequency decreases. The bottom scouring occurs for large gate opening rather than smaller one. The unstable operation conditions can be estimated by using the CFD results and the Strouhal number results for various gate opening gaps.

  15. Flow-induced vibration and flow characteristics prediction for a sliding roller gate by two-dimensional unsteady CFD simulation

    International Nuclear Information System (INIS)

    Kim, Nak-Geun; Lee, Kye-Bock; Cho, Yong

    2017-01-01

    Numerical analysis on the flow induced vibration and flow characteristics in the water gate has been carried out by 2-dimensional unsteady CFD simulation when sea water flows into the port in the river. Effect of gate opening on the frequency and the mean velocity and the vortex shedding under the water gate were studied. The streamlines were compared for various gate openings. To get the frequency spectrum, Fourier transform should be performed. Spectral analysis of the excitation force signals permitted identification of the main characteristics of the interaction process. The results show that the sources of disturbed frequency are the vortex shedding from under the water gate. As the gate opening ratio increases, the predicted vibration frequency decreases. The bottom scouring occurs for large gate opening rather than smaller one. The unstable operation conditions can be estimated by using the CFD results and the Strouhal number results for various gate opening gaps.

  16. Exact partial solution to the compressible flow problems of jet formation and penetration in plane, steady flow

    International Nuclear Information System (INIS)

    Karpp, R.R.

    1984-01-01

    The particle solution of the problem of the symmetric impact of two compressible fluid stream is derived. The plane two-dimensional flow is assumed to be steady, and the inviscid compressible fluid is of the Chaplygin (tangent gas) type. The equations governing this flow are transformed to the hodograph plane where an exact, closed-form solution for the stream function is obtained. The distribution of fluid properties along the plane of symmetry and the shape of free surface streamlines are determined by transformation back to the physical plane. The problem of a compressible fluid jet penetrating an infinite target of similar material is also solved by considering a limiting case of this solution. Differences between compressible and incompressible flows of the type considered are illustrated

  17. An Experimental investigation of critical flow rates of subcooled water through short pipes with small diameters

    International Nuclear Information System (INIS)

    Park, Choon Kyung

    1997-02-01

    The primary objective of this study is to improve our understanding on critical flow phenomena in a small size leak and to develop a model which can be used to estimate the critical mass flow rates through reactor vessel or primary coolant pipe wall. For this purpose, critical two-phase flow phenomena of subcooled water through short pipes (100 ≤ L ≤ 400 mm) with small diameters (3.4 ≤ D ≤ 7.15 mm) have been experimentally investigated for wide ranges of subcooling (0∼199 .deg. C) and pressure (0.5∼2.0MPa). To examine the effects of various parameters (i.e., the location of flashing inception, the degree of subcooling, the stagnation temperature and pressure, and the pipe size) on the critical two-phase flow rates of subcooled water, a total of 135 runs were made for various combinations of test parameters using four different L/D test sections. Experimental results that show effects of various parameters on subcooled critical two-phase flow rates are presented. The measured static pressure profiles along the discharge pipe show that the critical flow rate can be strongly influenced by the flashing location. The locations of saturation pressure for different values of the stagnation subcooling have been consistently determined from the pressure profiles. Based upon the test results, two important parameters have been identified. These are cold state discharge coefficient and dimensionless subcooling, which are found to efficiently take into account the test section geometry and the stagnation conditions, respectively. A semi-empirical model has been developed to predict subcooled two-phase flow rates through small size openings. This model provides a simple and direct calculation of the critical mass flow rates with information on the initial condition and on the test section geometry. Comparisons between the mass fluxes calculated by present model and a total of 755 selected experimental data from 9 different investigators show that the agreement is

  18. Three-dimensional analysis of the coolant flow characteristics in the fuel assemblies of VVER-1000 reactors

    International Nuclear Information System (INIS)

    Dinh Van Thin; Tran Thi Nhan

    2015-01-01

    Computational Fluid Dynamics (CFD) is a widely used method around the world for complex flow and heat industrial problems. In this paper, the coolant flow parameters were investigated in subchannels of VVER-1000 reactor’s fuel assemblies by ANSYS V14.5 programme. The different mesh solutions and turbulence models were carried out to deal with the water flow problems such as velocity distribution, streamline, temperature and pressure change as well as the hydraulic resistances of the spacer grids. The obtained results are good agreement with the measured values and the published reports from other authors. (author)

  19. Homogeneous non-equilibrium two-phase critical flow model

    International Nuclear Information System (INIS)

    Schroeder, J.J.; Vuxuan, N.

    1987-01-01

    An important aspect of nuclear and chemical reactor safety is the ability to predict the maximum or critical mass flow rate from a break or leak in a pipe system. At the beginning of such a blowdown, if the stagnation condition of the fluid is subcooled or slightly saturated thermodynamic non-equilibrium exists in the downstream, e.g. the fluid becomes superheated to a degree determined by the liquid pressure. A simplified non-equilibrium model, explained in this report, is valid for rapidly decreasing pressure along the flow path. It presumes that fluid has to be superheated by an amount governed by physical principles before it starts to flash into steam. The flow is assumed to be homogeneous, i.e. the steam and liquid velocities are equal. An adiabatic flow calculation mode (Fanno lines) is employed to evaluate the critical flow rate for long pipes. The model is found to satisfactorily describe critical flow tests. Good agreement is obtained with the large scale Marviken tests as well as with small scale experiments. (orig.)

  20. Streamlined Approach for Environmental Restoration Plan for Corrective Action Unit 121: Storage Tanks and Miscellaneous Sites, Nevada Test Site, Nevada

    International Nuclear Information System (INIS)

    NSTec Environmental Restoration

    2007-01-01

    This Streamlined Approach for Environmental Restoration (SAFER) Plan identifies the activities required for the closure of Corrective Action Unit (CAU) 121, Storage Tanks and Miscellaneous Sites. CAU 121 is currently listed in Appendix III of the ''Federal Facility Agreement and Consent Order'' (FFACO, 1996) and consists of three Corrective Action Sites (CASs) located in Area 12 of the Nevada Test Site (NTS): CAS 12-01-01, Aboveground Storage Tank; CAS 12-01-02, Aboveground Storage Tank; and CAS 12-22-26, Drums; 2 AST's. CASs 12-01-01 and 12-01-02 are located to the west of the Area 12 Camp, and CAS 12-22-26 is located near the U-12g Tunnel, also known as G-tunnel, in Area 12 (Figure 1). The aboveground storage tanks (ASTs) present at CASs 12-01-01 and 12-01-02 will be removed and disposed of at an appropriate facility. Soil below the ASTs will be sampled to identify whether it has been impacted with chemicals or radioactivity above action levels. If impacted soil above action levels is present, the soil will be excavated and disposed of at an appropriate facility. The CAS 12-22-26 site is composed of two overlapping areas, one where drums had formerly been stored, and the other where an AST was used to dispense diesel for locomotives used at G-tunnel. This area is located above an underground radioactive materials area (URMA), and within an area that may have elevated background radioactivity because of containment breaches during nuclear tests and associated tunnel reentry operations. CAS 12-22-26 does not include the URMA or the elevated background radioactivity. An AST that had previously been used to store liquid magnesium chloride (MgCl) was properly disposed of several years ago, and releases from this tank are not an environmental concern. The diesel AST will be removed and disposed of at an appropriate facility. Soil at the former drum area and the diesel AST area will be sampled to identify whether it has been impacted by releases, from the drums or the

  1. Generalization of measurements of local and integral heat transfer while transverse stream-lining of smooth and rough cylinders

    International Nuclear Information System (INIS)

    Akhenbakh, Eh.

    1976-01-01

    The investigation is presented into heat transfer in the boundary layer and in the tear-away region of a rough round cylinder. The data obtained must aid in improving nuclear reactor heat exchangers. The experiments were carried out in the Re range between 2 x 10 4 and 4 x 10 6 . The roughness parameter k 5 /d (where ksub(S) is the equivalent roughness, and d is the cylinder diameter) varied in the range 0 -5 . The degree of turbulence of the incident flow Tu = 0.45%. Heat transfer values are given in relation to Re and the roughness parameter in subcritical, critical, supercritical, and transcritical flows

  2. A Numerical Study of the Effect of Non-equilibrium Condensation on the Oscillation of Shock Wave in a Transonic Airfoil Flow

    Energy Technology Data Exchange (ETDEWEB)

    Kim, In Won; Kwon, Young Doo; Kwon, Soon Bum [Kyungpook Nat' l Univ., Daegu (Korea, Republic of); Jeon, Heung Kyun [Daegu Health College, Daegu (Korea, Republic of)

    2014-03-15

    In this study, to find the characteristics of the oscillation of a terminating shock wave in a transonic airfoil flow with non-equilibrium condensation, a NACA00-12,14,15 airfoil flow with non-equilibrium condensation is investigated through numerical analysis of TVD scheme. Transonic free stream Mach number of 0.81-0.90 with the variation of stagnation relative humidity and airfoil thickness is tested. For the free stream Mach number 0.87 and attack angle of α=0 .deg., the increase in stagnation relative humidity attenuates the strength of the terminating shock wave and inactivates the oscillation of the terminating shock wave. For the case of M{sub ∞}=0.87 and φ{sub 0}=60%, the decreasing rate in the frequency of the shock oscillation caused by non-equilibrium condensation to that of φ{sub 0}=30% amounts to 5%. Also, as the stagnation relative humidity gets larger, the maximum coefficient of drag and the difference between the maximum and minimum in C{sub D} become smaller. On the other hand, as the thickness of the airfoil gets larger, the supersonic bubble size becomes bigger and the oscillation of the shock wave becomes higher.

  3. A Numerical Study of the Effect of Non-equilibrium Condensation on the Oscillation of Shock Wave in a Transonic Airfoil Flow

    International Nuclear Information System (INIS)

    Kim, In Won; Kwon, Young Doo; Kwon, Soon Bum; Jeon, Heung Kyun

    2014-01-01

    In this study, to find the characteristics of the oscillation of a terminating shock wave in a transonic airfoil flow with non-equilibrium condensation, a NACA00-12,14,15 airfoil flow with non-equilibrium condensation is investigated through numerical analysis of TVD scheme. Transonic free stream Mach number of 0.81-0.90 with the variation of stagnation relative humidity and airfoil thickness is tested. For the free stream Mach number 0.87 and attack angle of α=0 .deg., the increase in stagnation relative humidity attenuates the strength of the terminating shock wave and inactivates the oscillation of the terminating shock wave. For the case of M ∞ =0.87 and φ 0 =60%, the decreasing rate in the frequency of the shock oscillation caused by non-equilibrium condensation to that of φ 0 =30% amounts to 5%. Also, as the stagnation relative humidity gets larger, the maximum coefficient of drag and the difference between the maximum and minimum in C D become smaller. On the other hand, as the thickness of the airfoil gets larger, the supersonic bubble size becomes bigger and the oscillation of the shock wave becomes higher

  4. Heat transfer and pressure drop characteristics of the tube bank fin heat exchanger with fin punched with flow redistributors and curved triangular vortex generators

    Science.gov (United States)

    Liu, Song; Jin, Hua; Song, KeWei; Wang, LiangChen; Wu, Xiang; Wang, LiangBi

    2017-10-01

    The heat transfer performance of the tube bank fin heat exchanger is limited by the air-side thermal resistance. Thus, enhancing the air-side heat transfer is an effective method to improve the performance of the heat exchanger. A new fin pattern with flow redistributors and curved triangular vortex generators is experimentally studied in this paper. The effects of the flow redistributors located in front of the tube stagnation point and the curved vortex generators located around the tube on the characteristics of heat transfer and pressure drop are discussed in detail. A performance comparison is also carried out between the fins with and without flow redistributors. The experimental results show that the flow redistributors stamped out from the fin in front of the tube stagnation points can decrease the friction factor at the cost of decreasing the heat transfer performance. Whether the combination of the flow redistributors and the curved vortex generators will present a better heat transfer performance depends on the size of the curved vortex generators. As for the studied two sizes of vortex generators, the heat transfer performance is promoted by the flow redistributors for the fin with larger size of vortex generators and the performance is suppressed by the flow redistributors for the fin with smaller vortex generators.

  5. Rules for Flight Paths and Time of Flight for Flows in Porous Media with Heterogeneous Permeability and Porosity

    Directory of Open Access Journals (Sweden)

    Lihua Zuo

    2017-01-01

    Full Text Available Porous media like hydrocarbon reservoirs may be composed of a wide variety of rocks with different porosity and permeability. Our study shows in algorithms and in synthetic numerical simulations that the flow pattern of any particular porous medium, assuming constant fluid properties and standardized boundary and initial conditions, is not affected by any spatial porosity changes but will vary only according to spatial permeability changes. In contrast, the time of flight along the streamline will be affected by both the permeability and porosity, albeit in opposite directions. A theoretical framework is presented with evidence from flow visualizations. A series of strategically chosen streamline simulations, including systematic spatial variations of porosity and permeability, visualizes the respective effects on the flight path and time of flight. Two practical rules are formulated. Rule  1 states that an increase in permeability decreases the time of flight, whereas an increase in porosity increases the time of flight. Rule  2 states that the permeability uniquely controls the flight path of fluid flow in porous media; local porosity variations do not affect the streamline path. The two rules are essential for understanding fluid transport mechanisms, and their rigorous validation therefore is merited.

  6. Analysis of atmospheric flow over a surface protrusion using the turbulence kinetic energy equation with reference to aeronautical operating systems

    Science.gov (United States)

    Frost, W.; Harper, W. L.

    1975-01-01

    Flow over surface obstructions can produce significantly large wind shears such that adverse flying conditions can occur for aeronautical systems (helicopters, STOL vehicles, etc.). Atmospheric flow fields resulting from a semi-elliptical surface obstruction in an otherwise horizontally homogeneous statistically stationary flow are modelled with the boundary-layer/Boussinesq-approximation of the governing equation of fluid mechanics. The turbulence kinetic energy equation is used to determine the dissipative effects of turbulent shear on the mean flow. Iso-lines of turbulence kinetic energy and turbulence intensity are plotted in the plane of the flow and highlight regions of high turbulence intensity in the stagnation zone and sharp gradients in intensity along the transition from adverse to favourable pressure gradient. Discussion of the effects of the disturbed wind field in CTOL and STOL aircraft flight path and obstruction clearance standards is given. The results indicate that closer inspection of these presently recommended standards as influenced by wind over irregular terrains is required.

  7. Laminar or turbulent boundary-layer flows of perfect gases or reacting gas mixtures in chemical equilibrium

    Science.gov (United States)

    Anderson, E. C.; Lewis, C. H.

    1971-01-01

    Turbulent boundary layer flows of non-reacting gases are predicted for both interal (nozzle) and external flows. Effects of favorable pressure gradients on two eddy viscosity models were studied in rocket and hypervelocity wind tunnel flows. Nozzle flows of equilibrium air with stagnation temperatures up to 10,000 K were computed. Predictions of equilibrium nitrogen flows through hypervelocity nozzles were compared with experimental data. A slender spherically blunted cone was studied at 70,000 ft altitude and 19,000 ft/sec. in the earth's atmosphere. Comparisons with available experimental data showed good agreement. A computer program was developed and fully documented during this investigation for use by interested individuals.

  8. To compare the efficacy of two kinds of Zhizhu pills in the treatment of functional dyspepsia of spleen-deficiency and qi-stagnation syndrome:a randomized group sequential comparative trial

    Science.gov (United States)

    2011-01-01

    Background In Traditional Chinese Medicine (TCM) theory, functional dyspepsia (FD) can be divided into different syndromes according to different clinical symptoms and signs, and the most common one is spleen-deficiency and qi-stagnation syndrome that can be treated by Chinese traditional patent medicine ---- two kinds of Zhizhu pills, between which the primary difference in ingredients is that one contains immature orange fruit of Citrus aurantium L.(IFCA) and the other contains that of Citrus sinensis Osbeck (IFCS). The trial's objective was to compare the efficacy of two kinds of Zhizhu pills on symptom changes in patients with FD of spleen-deficiency and qi-stagnation syndrome. Methods A randomized, group sequential, double-blinded, multicenter trial was conducted in patients with FD of spleen-deficiency and qi-stagnation syndrome at 3 hospitals in Beijing between June 2003 and May 2005. Participants were randomly allocated into two groups (IFCA group and IFCS group) in a 1:1 ratio, and respectively took one of the two kinds of Zhizhu pills orally, 6 g each time, 3 times a day, for 4 weeks. Statistical analysis was performed with use of a group sequential method, the triangular test (TT). Results A total of 163 patients were randomized, and 3 patients were excluded from analysis because of early dropouts, leaving 160 patients (IFCA group: n = 82; IFCS group: n = 78) for statistical analysis. Three interim analyses were done after 62, 116, and 160 patients had completed their 4-week treatment, respectively. At the third interim analysis, the sample path crossed the upper boundary and the trial was stopped, the cure-markedly effective rates were 45% for IFCS group and 67% for IFCA group, respectively, the one-sided p-value was 0.0036, the median unbiased estimate of the odds ratio (OR) for the benefit of IFCA relative to IFCS was 2.91 with 95%CI: 1.40 to 6.06. No adverse events were observed in the two groups. Conclusions Zhizhu pills containing IFCA was superior

  9. Flow visualization

    International Nuclear Information System (INIS)

    Weinstein, L.M.

    1991-01-01

    Flow visualization techniques are reviewed, with particular attention given to those applicable to liquid helium flows. Three techniques capable of obtaining qualitative and quantitative measurements of complex 3D flow fields are discussed including focusing schlieren, particle image volocimetry, and holocinematography (HCV). It is concluded that the HCV appears to be uniquely capable of obtaining full time-varying, 3D velocity field data, but is limited to the low speeds typical of liquid helium facilities. 8 refs

  10. Numerical Analysis of the Cavity Flow subjected to Passive Controls Techniques

    Science.gov (United States)

    Melih Guleren, Kursad; Turk, Seyfettin; Mirza Demircan, Osman; Demir, Oguzhan

    2018-03-01

    Open-source flow solvers are getting more and more popular for the analysis of challenging flow problems in aeronautical and mechanical engineering applications. They are offered under the GNU General Public License and can be run, examined, shared and modified according to user’s requirements. SU2 and OpenFOAM are the two most popular open-source solvers in Computational Fluid Dynamics (CFD) community. In the present study, some passive control methods on the high-speed cavity flows are numerically simulated using these open-source flow solvers along with one commercial flow solver called ANSYS/Fluent. The results are compared with the available experimental data. The solver SU2 are seen to predict satisfactory the mean streamline velocity but not turbulent kinetic energy and overall averaged sound pressure level (OASPL). Whereas OpenFOAM predicts all these parameters nearly as the same levels of ANSYS/Fluent.

  11. Flow regimes

    International Nuclear Information System (INIS)

    Liles, D.R.

    1982-01-01

    Internal boundaries in multiphase flow greatly complicate fluid-dynamic and heat-transfer descriptions. Different flow regimes or topological configurations can have radically dissimilar interfacial and wall mass, momentum, and energy exchanges. To model the flow dynamics properly requires estimates of these rates. In this paper the common flow regimes for gas-liquid systems are defined and the techniques used to estimate the extent of a particular regime are described. Also, the current computer-code procedures are delineated and introduce a potentially better method is introduced

  12. Calculation of Thomson scattering spectral fits for interpenetrating flows

    Energy Technology Data Exchange (ETDEWEB)

    Swadling, G. F., E-mail: george.swadling@imperial.ac.uk; Lebedev, S. V., E-mail: george.swadling@imperial.ac.uk; Burdiak, G. C.; Suttle, L.; Patankar, S.; Smith, R. A.; Bennett, M.; Suzuki-Vidal, F. [Blackett Laboratory, Imperial College, London SW7 2BW (United Kingdom); Harvey-Thompson, A. J. [Sandia National Laboratories, PO Box 5800, Albuquerque, New Mexico 87185-1193 (United States); Rozmus, W. [Department of Physics, University of Alberta, Edmonton, Alberta T6G 2JI (Canada); Hall, G. N. [Blackett Laboratory, Imperial College, London, United Kingdom SW7 2BW and Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94551 (United States); Yuan, J. [Key Laboratory of Pulsed Power, Institute of Fluid Physics, CAE, Mianyang 621900 (China)

    2014-12-15

    Collective mode optical Thomson scattering has been used to investigate the interactions of radially convergent ablation flows in Tungsten wire arrays. These experiments were carried out at the Magpie pulsed power facility at Imperial College, London. Analysis of the scattered spectra has provided direct evidence of ablation stream interpenetration on the array axis, and has also revealed a previously unobserved axial deflection of the ablation streams towards the anode as they approach the axis. It is has been suggested that this deflection is caused by the presence of a static magnetic field, advected with the ablation streams, stagnated and accrued around the axis. Analysis of the Thomson scattering spectra involved the calculation and fitting of the multi-component, non-relativistic, Maxwellian spectral density function S (k, ω). The method used to calculate the fits of the data are discussed in detail.

  13. DNS of flows over superhydrophobic surfaces with small texture

    Science.gov (United States)

    Fairhall, Chris; Garcia-Mayoral, Ricardo

    2015-11-01

    We present results from direct numerical simulations of turbulent flows over superhydrophobic surfaces with small texture sizes, comparable to those of practical application. Textures studied with DNS are usually much larger, as the cost of the simulations would otherwise be prohibitive. For this reason, a multi-block code that allows for finer resolution near the walls has been developed. We focus particularly on the pressure distribution at the wall. This distribution can cause the deformation of the gas pockets, which can ultimately lead to their loss and that of the drag reduction effect. The layout of the texture causes stagnation pressures which can contribute substantially to the wall pressure signal (Seo et al. JFM, under review). We study a range of different textures and their influence on these pressures.

  14. Determination of averaged axisymmetric flow surfaces according to results obtained by numerical simulation of flow in turbomachinery

    Directory of Open Access Journals (Sweden)

    Bogdanović-Jovanović Jasmina B.

    2012-01-01

    Full Text Available In the increasing need for energy saving worldwide, the designing process of turbomachinery, as an essential part of thermal and hydroenergy systems, goes in the direction of enlarging efficiency. Therefore, the optimization of turbomachinery designing strongly affects the energy efficiency of the entire system. In the designing process of turbomachinery blade profiling, the model of axisymmetric fluid flows is commonly used in technical practice, even though this model suits only the profile cascades with infinite number of infinitely thin blades. The actual flow in turbomachinery profile cascades is not axisymmetric, and it can be fictively derived into the axisymmetric flow by averaging flow parameters in the blade passages according to the circular coordinate. Using numerical simulations of flow in turbomachinery runners, its operating parameters can be preliminarily determined. Furthermore, using the numerically obtained flow parameters in the blade passages, averaged axisymmetric flow surfaces in blade profile cascades can also be determined. The method of determination of averaged flow parameters and averaged meridian streamlines is presented in this paper, using the integral continuity equation for averaged flow parameters. With thus obtained results, every designer can be able to compare the obtained averaged flow surfaces with axisymmetric flow surfaces, as well as the specific work of elementary stages, which are used in the procedure of blade designing. Numerical simulations of flow in an exemplary axial flow pump, used as a part of the thermal power plant cooling system, were performed using Ansys CFX. [Projekat Ministarstva nauke Republike Srbije, br. TR33040: Revitalization of existing and designing new micro and mini hydropower plants (from 100 kW to 1000 kW in the territory of South and Southeast Serbia

  15. Parametric Study of Cantilever Plates Exposed to Supersonic and Hypersonic Flows

    Science.gov (United States)

    Sri Harsha, A.; Rizwan, M.; Kuldeep, S.; Giridhara Prasad, A.; Akhil, J.; Nagaraja, S. R.

    2017-08-01

    Analysis of hypersonic flows associated with re-entry vehicles has gained a lot of significance due to the advancements in Aerospace Engineering. An area that is studied extensively by researchers is the simultaneous reduction aerodynamic drag and aero heating in re-entry vehicles. Out of the many strategies being studied, the use of aerospikes at the stagnation point of the vehicle is found to give favourable results. The structural stability of the aerospike becomes important as it is exposed to very high pressures and temperatures. Keeping this in view, the deflection and vibration of an inclined cantilever plate in hypersonic flow is carried out using ANSYS. Steady state pressure distribution obtained from Fluent is applied as load to the transient structural module for analysis. After due validation of the methods, the effects of parameters like flow Mach number, plate inclination and plate thickness on the deflection and vibration are studied.

  16. Effect of Axisymmetric Aft Wall Angle Cavity in Supersonic Flow Field

    Science.gov (United States)

    Jeyakumar, S.; Assis, Shan M.; Jayaraman, K.

    2018-03-01

    Cavity plays a significant role in scramjet combustors to enhance mixing and flame holding of supersonic streams. In this study, the characteristics of axisymmetric cavity with varying aft wall angles in a non-reacting supersonic flow field are experimentally investigated. The experiments are conducted in a blow-down type supersonic flow facility. The facility consists of a supersonic nozzle followed by a circular cross sectional duct. The axisymmetric cavity is incorporated inside the duct. Cavity aft wall is inclined with two consecutive angles. The performance of the aft wall cavities are compared with rectangular cavity. Decreasing aft wall angle reduces the cavity drag due to the stable flow field which is vital for flame holding in supersonic combustor. Uniform mixing and gradual decrease in stagnation pressure loss can be achieved by decreasing the cavity aft wall angle.

  17. Heat transfer in gas turbine engines and three-dimensional flows; Proceedings of the Symposium, ASME Winter Annual Meeting, Chicago, IL, Nov. 27-Dec. 2, 1988

    Science.gov (United States)

    Elovic, E. (Editor); O'Brien, J. E. (Editor); Pepper, D. W. (Editor)

    1988-01-01

    The present conference on heat transfer characteristics of gas turbines and three-dimensional flows discusses velocity-temperature fluctuation correlations at the flow stagnation flow of a circular cylinder in turbulent flow, heat transfer across turbulent boundary layers with pressure gradients, the effect of jet grid turbulence on boundary layer heat transfer, and heat transfer characteristics predictions for discrete-hole film cooling. Also discussed are local heat transfer in internally cooled turbine airfoil leading edges, secondary flows in vane cascades and curved ducts, three-dimensional numerical modeling in gas turbine coal combustor design, numerical and experimental results for tube-fin heat exchanger airflow and heating characteristics, and the computation of external hypersonic three-dimensional flow field and heat transfer characteristics.

  18. Dual Solutions for Nonlinear Flow Using Lie Group Analysis.

    Directory of Open Access Journals (Sweden)

    Muhammad Awais

    Full Text Available `The aim of this analysis is to investigate the existence of the dual solutions for magnetohydrodynamic (MHD flow of an upper-convected Maxwell (UCM fluid over a porous shrinking wall. We have employed the Lie group analysis for the simplification of the nonlinear differential system and computed the absolute invariants explicitly. An efficient numerical technique namely the shooting method has been employed for the constructions of solutions. Dual solutions are computed for velocity profile of an upper-convected Maxwell (UCM fluid flow. Plots reflecting the impact of dual solutions for the variations of Deborah number, Hartman number, wall mass transfer are presented and analyzed. Streamlines are also plotted for the wall mass transfer effects when suction and blowing situations are considered.

  19. Vorticity amplification and its effects on flow separation from simplified landing gear wheels

    Science.gov (United States)

    McCarthy, Philip; Feltham, Graham; Ekmekci, Alis

    2015-11-01

    In the presence of weak streams of inbound vorticity, the stagnation region of bluff bodies have been shown to support mechanisms for the collection and amplification of said vorticity into large-scale, discrete vortex structures. For extremely low aspect ratio cylinders, such as those which represent simplified aircraft landing gear wheels, these discrete vortex structures tilt around the sides of the geometry, orientating their axes in the streamwise direction. Once the oncoming vorticity is collected and amplified into discrete vortices, they are shed from the stagnation region and this cycle repeats itself periodically. The present work investigates the effect of the vortex tilting and subsequent shedding on the behaviour of the outboard side flow separation region present on simplified landing gear wheels. Experiments were conducted in a recirculating-type water tunnel on a two-wheel landing gear model, with the upstream vorticity source being a 100 µm platinum wire. Hydrogen bubble visualisations were first used for qualitative understanding of the flow, accompanied by 2D-PIV for vortex identification and tracking of the growth and movement of the observed structures. Finally, the side separation bubble has been characterised using 3D velocity measurements (using V3V). The authors would like to thank Bombardier, Messier-Bugatti-Dowty and NSERC for their support for this project.

  20. Streamlined Approach for Environmental Restoration Plan for Corrective Action Unit 484: Surface Debris, Waste Sites, and Burn Area, Tonopah Test Range, Nevada

    International Nuclear Information System (INIS)

    Bechel Nevada

    2004-01-01

    This Streamlined Approach for Environmental Restoration plan details the activities necessary to close Corrective Action Unit (CAU) 484: Surface Debris, Waste Sites, and Burn Area (Tonopah Test Range). CAU 484 consists of sites located at the Tonopah Test Range, Nevada, and is currently listed in Appendix III of the Federal Facility Agreement and Consent Order. CAU 484 consists of the following six Corrective Action Sites: (1) CAS RG-52-007-TAML, Davis Gun Penetrator Test; (2) CAS TA-52-001-TANL, NEDS Detonation Area; (3) CAS TA-52-004-TAAL, Metal Particle Dispersion Test; (4) CAS TA-52-005-TAAL, Joint Test Assembly DU Sites; (5) CAS TA-52-006-TAPL, Depleted Uranium Site; and (6) CAS TA-54-001-TANL, Containment Tank and Steel Structure

  1. Streamlined approach for environmental restoration plan for corrective action unit 430, buried depleted uranium artillery round No. 1, Tonopah test range

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-09-01

    This plan addresses actions necessary for the restoration and closure of Corrective Action Unit (CAU) No. 430, Buried Depleted Uranium (DU) Artillery Round No. 1 (Corrective Action Site No. TA-55-003-0960), a buried and unexploded W-79 Joint Test Assembly (JTA) artillery test projectile with high explosives (HE), at the U.S. Department of Energy, Nevada Operations Office (DOE/NV) Tonopah Test Range (TTR) in south-central Nevada. It describes activities that will occur at the site as well as the steps that will be taken to gather adequate data to obtain a notice of completion from Nevada Division of Environmental Protection (NDEP). This plan was prepared under the Streamlined Approach for Environmental Restoration (SAFER) concept, and it will be implemented in accordance with the Federal Facility Agreement and Consent Order (FFACO) and the Resource Conservation and Recovery Act (RCRA) Industrial Sites Quality Assurance Project Plan.

  2. Streamlined Approach for Environmental Restoration Plan for Corrective Action Unit 113: Reactor Maintenance, Assembly, and Disassembly Building Nevada Test Site, Nevada

    International Nuclear Information System (INIS)

    Smith, J. L.

    2001-01-01

    This Streamlined Approach for Environmental Restoration (SAFER) Plan addresses the action necessary for the closure in place of Corrective Action Unit (CAU) 113 Area 25 Reactor Maintenance, Assembly, and Disassembly Facility (R-MAD). CAU 113 is currently listed in Appendix III of the Federal Facility Agreement and Consent Order (FFACO) (NDEP, 1996). The CAU is located in Area 25 of the Nevada Test Site (NTS) and consists of Corrective Action Site (CAS) 25-04-01, R-MAD Facility (Figures 1-2). This plan provides the methodology for closure in place of CAU 113. The site contains radiologically impacted and hazardous material. Based on preassessment field work, there is sufficient process knowledge to close in place CAU 113 using the SAFER process. At a future date when funding becomes available, the R-MAD Building (25-3110) will be demolished and inaccessible radiologic waste will be properly disposed in the Area 3 Radiological Waste Management Site (RWMS)

  3. Streamlined Approach for Environmental Restoration Plan for Corrective Action Unit 113: Reactor Maintenance, Assembly, and Disassembly Building Nevada Test Site, Nevada

    Energy Technology Data Exchange (ETDEWEB)

    J. L. Smith

    2001-01-01

    This Streamlined Approach for Environmental Restoration (SAFER) Plan addresses the action necessary for the closure in place of Corrective Action Unit (CAU) 113 Area 25 Reactor Maintenance, Assembly, and Disassembly Facility (R-MAD). CAU 113 is currently listed in Appendix III of the Federal Facility Agreement and Consent Order (FFACO) (NDEP, 1996). The CAU is located in Area 25 of the Nevada Test Site (NTS) and consists of Corrective Action Site (CAS) 25-04-01, R-MAD Facility (Figures 1-2). This plan provides the methodology for closure in place of CAU 113. The site contains radiologically impacted and hazardous material. Based on preassessment field work, there is sufficient process knowledge to close in place CAU 113 using the SAFER process. At a future date when funding becomes available, the R-MAD Building (25-3110) will be demolished and inaccessible radiologic waste will be properly disposed in the Area 3 Radiological Waste Management Site (RWMS).

  4. Streamlined approach for environmental restoration plan for corrective action unit 430, buried depleted uranium artillery round No. 1, Tonopah test range

    International Nuclear Information System (INIS)

    1996-09-01

    This plan addresses actions necessary for the restoration and closure of Corrective Action Unit (CAU) No. 430, Buried Depleted Uranium (DU) Artillery Round No. 1 (Corrective Action Site No. TA-55-003-0960), a buried and unexploded W-79 Joint Test Assembly (JTA) artillery test projectile with high explosives (HE), at the U.S. Department of Energy, Nevada Operations Office (DOE/NV) Tonopah Test Range (TTR) in south-central Nevada. It describes activities that will occur at the site as well as the steps that will be taken to gather adequate data to obtain a notice of completion from Nevada Division of Environmental Protection (NDEP). This plan was prepared under the Streamlined Approach for Environmental Restoration (SAFER) concept, and it will be implemented in accordance with the Federal Facility Agreement and Consent Order (FFACO) and the Resource Conservation and Recovery Act (RCRA) Industrial Sites Quality Assurance Project Plan

  5. Rapid Evidence Assessment of the Literature (REAL(©)): streamlining the systematic review process and creating utility for evidence-based health care.

    Science.gov (United States)

    Crawford, Cindy; Boyd, Courtney; Jain, Shamini; Khorsan, Raheleh; Jonas, Wayne

    2015-11-02

    Systematic reviews (SRs) are widely recognized as the best means of synthesizing clinical research. However, traditional approaches can be costly and time-consuming and can be subject to selection and judgment bias. It can also be difficult to interpret the results of a SR in a meaningful way in order to make research recommendations, clinical or policy decisions, or practice guidelines. Samueli Institute has developed the Rapid Evidence Assessment of the Literature (REAL) SR process to address these issues. REAL provides up-to-date, rigorous, high quality SR information on health care practices, products, or programs in a streamlined, efficient and reliable manner. This process is a component of the Scientific Evaluation and Review of Claims in Health Care (SEaRCH™) program developed by Samueli Institute, which aims at answering the question of "What works?" in health care. The REAL process (1) tailors a standardized search strategy to a specific and relevant research question developed with various stakeholders to survey the available literature; (2) evaluates the quantity and quality of the literature using structured tools and rulebooks to ensure objectivity, reliability and reproducibility of reviewer ratings in an independent fashion and; (3) obtains formalized, balanced input from trained subject matter experts on the implications of the evidence for future research and current practice. Online tools and quality assurance processes are utilized for each step of the review to ensure a rapid, rigorous, reliable, transparent and reproducible SR process. The REAL is a rapid SR process developed to streamline and aid in the rigorous and reliable evaluation and review of claims in health care in order to make evidence-based, informed decisions, and has been used by a variety of organizations aiming to gain insight into "what works" in health care. Using the REAL system allows for the facilitation of recommendations on appropriate next steps in policy, funding

  6. Scientific Evaluation and Review of Claims in Health Care (SEaRCH): A Streamlined, Systematic, Phased Approach for Determining “What Works” in Healthcare

    Science.gov (United States)

    Crawford, Cindy; Hilton, Lara; Elfenbaum, Pamela

    2017-01-01

    Abstract Background: Answering the question of “what works” in healthcare can be complex and requires the careful design and sequential application of systematic methodologies. Over the last decade, the Samueli Institute has, along with multiple partners, developed a streamlined, systematic, phased approach to this process called the Scientific Evaluation and Review of Claims in Health Care (SEaRCH™). The SEaRCH process provides an approach for rigorously, efficiently, and transparently making evidence-based decisions about healthcare claims in research and practice with minimal bias. Methods: SEaRCH uses three methods combined in a coordinated fashion to help determine what works in healthcare. The first, the Claims Assessment Profile (CAP), seeks to clarify the healthcare claim and question, and its ability to be evaluated in the context of its delivery. The second method, the Rapid Evidence Assessment of the Literature (REAL©), is a streamlined, systematic review process conducted to determine the quantity, quality, and strength of evidence and risk/benefit for the treatment. The third method involves the structured use of expert panels (EPs). There are several types of EPs, depending on the purpose and need. Together, these three methods—CAP, REAL, and EP—can be integrated into a strategic approach to help answer the question “what works in healthcare?” and what it means in a comprehensive way. Discussion: SEaRCH is a systematic, rigorous approach for evaluating healthcare claims of therapies, practices, programs, or products in an efficient and stepwise fashion. It provides an iterative, protocol-driven process that is customized to the intervention, consumer, and context. Multiple communities, including those involved in health service and policy, can benefit from this organized framework, assuring that evidence-based principles determine which healthcare practices with the greatest promise are used for improving the public's health and

  7. Scientific Evaluation and Review of Claims in Health Care (SEaRCH): A Streamlined, Systematic, Phased Approach for Determining "What Works" in Healthcare.

    Science.gov (United States)

    Jonas, Wayne B; Crawford, Cindy; Hilton, Lara; Elfenbaum, Pamela

    2017-01-01

    Answering the question of "what works" in healthcare can be complex and requires the careful design and sequential application of systematic methodologies. Over the last decade, the Samueli Institute has, along with multiple partners, developed a streamlined, systematic, phased approach to this process called the Scientific Evaluation and Review of Claims in Health Care (SEaRCH™). The SEaRCH process provides an approach for rigorously, efficiently, and transparently making evidence-based decisions about healthcare claims in research and practice with minimal bias. SEaRCH uses three methods combined in a coordinated fashion to help determine what works in healthcare. The first, the Claims Assessment Profile (CAP), seeks to clarify the healthcare claim and question, and its ability to be evaluated in the context of its delivery. The second method, the Rapid Evidence Assessment of the Literature (REAL © ), is a streamlined, systematic review process conducted to determine the quantity, quality, and strength of evidence and risk/benefit for the treatment. The third method involves the structured use of expert panels (EPs). There are several types of EPs, depending on the purpose and need. Together, these three methods-CAP, REAL, and EP-can be integrated into a strategic approach to help answer the question "what works in healthcare?" and what it means in a comprehensive way. SEaRCH is a systematic, rigorous approach for evaluating healthcare claims of therapies, practices, programs, or products in an efficient and stepwise fashion. It provides an iterative, protocol-driven process that is customized to the intervention, consumer, and context. Multiple communities, including those involved in health service and policy, can benefit from this organized framework, assuring that evidence-based principles determine which healthcare practices with the greatest promise are used for improving the public's health and wellness.

  8. Numerical Simulation on Forced Convective Condensation of Steam Upward Flow in a Vertical Pipe

    Directory of Open Access Journals (Sweden)

    Guo-Dong Qiu

    2014-05-01

    Full Text Available A transient three-dimensional volume of fluid (VOF simulation on condensation of upward flow of wet steam inside a 12 mm i.d. vertical pipe is presented. The effect of gravity and surface tension are taken into account. A uniform wall temperature has been fixed as boundary conditions. The mass flux is 130~6400 kg m−2's−1 and the turbulence inside the vapor phase and liquid phase have been handled by Reynolds stress model (RSM. The vapor quality of fluid is 0~0.4. The numerical simulation results show that, in all the simulation conditions, the bubbly flow, slug flow, churn flow, wispy annular flow, and annular flow are observed; in addition, the results of flow pattern are in good agreement with the regime map from Hewitt and Roberts. The typical velocity field characteristic of each flow pattern and the effect of velocity field on heat transfer of condensation are analyzed, indicating that the slug flow and churn flow have obvious local eddy. However, no obvious eddy is observed in other flow patterns and the streamlines are almost parallel to the flow direction. The simulation results of heat transfer coefficients and frictional pressure drop show good agreement with the correlations from existing literatures.

  9. The effect of forward skewed rotor blades on aerodynamic and aeroacoustic performance of axial-flow fan

    Science.gov (United States)

    Wei, Jun; Zhong, Fangyuan

    Based on comparative experiment, this paper deals with using tangentially skewed rotor blades in axial-flow fan. It is seen from the comparison of the overall performance of the fan with skewed bladed rotor and radial bladed rotor that the skewed blades operate more efficiently than the radial blades, especially at low volume flows. Meanwhile, decrease in pressure rise and flow rate of axial-flow fan with skewed rotor blades is found. The rotor-stator interaction noise and broadband noise of axial-flow fan are reduced with skewed rotor blades. Forward skewed blades tend to reduce the accumulation of the blade boundary layer in the tip region resulting from the effect of centrifugal forces. The turning of streamlines from the outer radius region into inner radius region in blade passages due to the radial component of blade forces of skewed blades is the main reason for the decrease in pressure rise and flow rate.

  10. Investigation and visualization of internal flow through particle aggregates and microbial flocs using particle image velocimetry.

    Science.gov (United States)

    Xiao, Feng; Lam, Kit Ming; Li, Xiao-yan

    2013-05-01

    An advanced particle-tracking and flow-visualization technology, particle image velocimetry (PIV), was utilized to investigate the hydrodynamic properties of large aggregates in water. The laser-based PIV system was used together with a settling column to capture the streamlines around two types of aggregates: latex particle aggregates and activated sludge (AS) flocs. Both types of the aggregates were highly porous and fractal with fractal dimensions of 2.13±0.31 for the latex particle aggregates (1210-2144 μm) and 1.78±0.24 for the AS flocs (1265-3737 μm). The results show that PIV is a powerful flow visualization technique capable of determining flow field details at the micrometer scale around and through settling aggregates and flocs. The PIV streamlines provided direct experimental proof of internal flow through the aggregate interiors. According to the PIV images, fluid collection efficiency ranged from 0.052 to 0.174 for the latex particle aggregates and from 0.008 to 0.126 for AS flocs. AS flocs are apparently less permeable than the particle aggregates, probably due to the extracellular polymeric substances (EPSs) produced by bacteria clogging the pores within the flocs. The internal permeation of fractal aggregates and bio-flocs would enhance flocculation between particles and material transport into the aggregates. Copyright © 2013 Elsevier Inc. All rights reserved.

  11. On the flow of an electrically conducting gas past a slender body of revolution placed in a circular wind tunnel in the presence of a crossed magnetic field

    International Nuclear Information System (INIS)

    Suwa, Shigeaki; Kusukawa, Ken-ichi.

    1976-01-01

    The wind tunnel interference problem in magnetohydrodynamics, in which an inviscid compressible fluid with small electrical conductivity flows steadily past a slender axi-symmetric pointed body of revolution placed in a cylindrical perfectly insulated wind tunnel, in the presence of a crossed magnetic field, is considered. Using the analytical method which was studied by one of the present authors, the streamlines and the space charge in a cross section are calculated. (auth.)

  12. Fast ion distribution in the presence of flow

    Science.gov (United States)

    Davidovits, Seth; Fisch, Nathaniel

    2014-10-01

    Experiments and simulations in multiple ICF related configurations have observed signs of bulk flow near stagnation. These configurations include both laser driven implosions such as at the NIF, as well as Z-Pinches. We investigate the possibilities for enhancement or depletion of fast ion tails in simplified flow models, with an eye towards applicability to ICF experiments. Small effects on the tail populations may substantially affect fusion output, as the fast ions in these tails have much larger fusion cross sections than thermal ions and make up the majority of fusion production for typical ICF temperatures. While in collisional plasma the bulk of the distribution function is driven toward Maxwellian in a few collision times, the high velocity tails can take much longer to form. Furthermore, the long mean free paths of the fast ions means they may sample differing regions of flow, while thermal particles only sample the local flow. This work was supported by DOE through Contracts DE-AC02-09CH1-1466 and 67350-9960 (Prime # DOE DE-NA0001836). Seth Davidovits would like to acknowledge support by the DOE-CSGF program under Grant DE-FG02-97ER25308.

  13. Stability of hypersonic boundary-layer flows with chemistry

    Science.gov (United States)

    Reed, Helen L.; Stuckert, Gregory K.; Haynes, Timothy S.

    1993-01-01

    The effects of nonequilibrium chemistry and three dimensionality on the stability characteristics of hypersonic flows are discussed. In two-dimensional (2-D) and axisymmetric flows, the inclusion of chemistry causes a shift of the second mode of Mack to lower frequencies. This is found to be due to the increase in size of the region of relative supersonic flow because of the lower speeds of sound in the relatively cooler boundary layers. Although this shift in frequency is present in both the equilibrium and nonequilibrium air results, the equilibrium approximation predicts modes which are not observed in the nonequilibrium calculations (for the flight conditions considered). These modes are superpositions of incoming and outgoing unstable disturbances which travel supersonically relative to the boundary-layer edge velocity. Such solutions are possible because of the finite shock stand-off distance. Their corresponding wall-normal profiles exhibit an oscillatory behavior in the inviscid region between the boundary-layer edge and the bow shock. For the examination of three-dimensional (3-D) effects, a rotating cone is used as a model of a swept wing. An increase of stagnation temperature is found to be only slightly stabilizing. The correlation of transition location (N = 9) with parameters describing the crossflow profile is discussed. Transition location does not correlate with the traditional crossflow Reynolds number. A new parameter that appears to correlate for boundary-layer flow was found. A verification with experiments on a yawed cone is provided.

  14. Computational fluid dynamics simulations of single-phase flow in a filter-press flow reactor having a stack of three cells

    International Nuclear Information System (INIS)

    Sandoval, Miguel A.; Fuentes, Rosalba; Walsh, Frank C.; Nava, José L.; Ponce de León, Carlos

    2016-01-01

    Highlights: • Computational fluid dynamic simulations in a filter-press stack of three cells. • The fluid velocity was different in each cell due to local turbulence. • The upper cell link pipe of the filter press cell acts as a fluid mixer. • The fluid behaviour tends towards a continuous mixing flow pattern. • Close agreement between simulations and experimental data was achieved. - Abstract: Computational fluid dynamics (CFD) simulations were carried out for single-phase flow in a pre-pilot filter press flow reactor with a stack of three cells. Velocity profiles and streamlines were obtained by solving the Reynolds-Averaged Navier-Stokes (RANS) equations with a standard k − ε turbulence model. The flow behaviour shows the appearance of jet flow at the entrance to each cell. At lengths from 12 to 15 cm along the cells channels, a plug flow pattern is developed at all mean linear flow rates studied here, 1.2 ≤ u ≤ 2.1 cm s −1 . The magnitude of the velocity profiles in each cell was different, due to the turbulence generated by the change of flow direction in the last fluid manifold. Residence time distribution (RTD) simulations indicated that the fluid behaviour tends towards a continuous mixing flow pattern, owing to flow at the output of each cell across the upper cell link pipe, which acts as a mixer. Close agreement between simulations and experimental RTD was obtained.

  15. CLARKE AND WRIGHT SAVING ALGORITHM AS A MEANS OF DISTRIBUTION STREAMLINING IN THE ENVIRONMENT OF A CONCRETE COMPANY

    Directory of Open Access Journals (Sweden)

    Martin Straka

    2015-03-01

    Full Text Available Reducing costs forces of companies to look for reserves also in field of management, support and implementation of material flow. This is connected with the optimization of costs for product distribution, which forms a significant part of the total cost of the company. In practice, it happens that making plans for distribution of materials within a distribution space is left solely to the implementers of distribution and it drivers of vehicles. As a result is uneconomic material distribution and unnecessary cost increases to his distribution. The objective of the paper is to propose a methodology for optimization of transport planning from DC Prešov to the individual Tesco units within the region that comes under this distribution centre. The methodology is based on the Clarke and Wright saving algorithm.

  16. Air flow quality analysis of modenas engine exhaust system

    Science.gov (United States)

    Shahriman A., B.; Mohamad Syafiq A., K.; Hashim, M. S. M.; Razlan, Zuradzman M.; Khairunizam W. A., N.; Hazry, D.; Afendi, Mohd; Daud, R.; Rahman, M. D. Tasyrif Abdul; Cheng, E. M.; Zaaba, S. K.

    2017-09-01

    The simulation process being conducted to determine the air flow effect between the original exhaust system and modified exhaust system. The simulations are conducted to investigate the flow distribution of exhaust gases that will affect the performance of the engine. The back flow pressure in the original exhaust system is predicted toward this simulation. The design modification to the exhaust port, exhaust pipe, and exhaust muffler has been done during this simulation to reduce the back flow effect. The new designs are introduced by enlarging the diameter of the exhaust port, enlarge the diameter of the exhaust pipe and created new design for the exhaust muffler. Based on the result obtained, there the pulsating flow form at the original exhaust port that will increase the velocity and resulting the back pressure occur. The result for new design of exhaust port, the velocity is lower at the valve guide in the exhaust port. New design muffler shows that the streamline of the exhaust flow move smoothly compare to the original muffler. It is proved by using the modification exhaust system, the back pressure are reduced and the engine performance can be improve.

  17. Simulation of the solidification in a channel of a water-cooled glass flow

    Directory of Open Access Journals (Sweden)

    G. E. Ovando Chacon

    2014-12-01

    Full Text Available A computer simulation study of a laminar steady-state glass flow that exits from a channel cooled with water is reported. The simulations are carried out in a two-dimensional, Cartesian channel with a backward-facing step for three different angles of the step and different glass outflow velocities. We studied the interaction of the fluid dynamics, phase change and thermal behavior of the glass flow due to the heat that transfers to the cooling water through the wall of the channel. The temperature, streamline, phase change and pressure fields are obtained and analyzed for the glass flow. Moreover, the temperature increments of the cooling water are characterized. It is shown that, by reducing the glass outflow velocity, the solidification is enhanced; meanwhile, an increase of the step angle also improves the solidification of the glass flow.

  18. Finite element methods in incompressible, adiabatic, and compressible flows from fundamental concepts to applications

    CERN Document Server

    Kawahara, Mutsuto

    2016-01-01

    This book focuses on the finite element method in fluid flows. It is targeted at researchers, from those just starting out up to practitioners with some experience. Part I is devoted to the beginners who are already familiar with elementary calculus. Precise concepts of the finite element method remitted in the field of analysis of fluid flow are stated, starting with spring structures, which are most suitable to show the concepts of superposition/assembling. Pipeline system and potential flow sections show the linear problem. The advection–diffusion section presents the time-dependent problem; mixed interpolation is explained using creeping flows, and elementary computer programs by FORTRAN are included. Part II provides information on recent computational methods and their applications to practical problems. Theories of Streamline-Upwind/Petrov–Galerkin (SUPG) formulation, characteristic formulation, and Arbitrary Lagrangian–Eulerian (ALE) formulation and others are presented with practical results so...

  19. A Quantized Boundary Representation of 2D Flows

    KAUST Repository

    Levine, J. A.

    2012-06-01

    Analysis and visualization of complex vector fields remain major challenges when studying large scale simulation of physical phenomena. The primary reason is the gap between the concepts of smooth vector field theory and their computational realization. In practice, researchers must choose between either numerical techniques, with limited or no guarantees on how they preserve fundamental invariants, or discrete techniques which limit the precision at which the vector field can be represented. We propose a new representation of vector fields that combines the advantages of both approaches. In particular, we represent a subset of possible streamlines by storing their paths as they traverse the edges of a triangulation. Using only a finite set of streamlines creates a fully discrete version of a vector field that nevertheless approximates the smooth flow up to a user controlled error bound. The discrete nature of our representation enables us to directly compute and classify analogues of critical points, closed orbits, and other common topological structures. Further, by varying the number of divisions (quantizations) used per edge, we vary the resolution used to represent the field, allowing for controlled precision. This representation is compact in memory and supports standard vector field operations.

  20. An analytical phantom for the evaluation of medical flow imaging algorithms

    International Nuclear Information System (INIS)

    Pashaei, A; Fatouraee, N

    2009-01-01

    Blood flow characteristics (e.g. velocity, pressure, shear stress, streamline and volumetric flow rate) are effective tools in diagnosis of cardiovascular diseases such as atherosclerotic plaque, aneurism and cardiac muscle failure. Noninvasive estimation of cardiovascular blood flow characteristics is mostly limited to the measurement of velocity components by medical imaging modalities. Once the velocity field is obtained from the images, other flow characteristics within the cardiovascular system can be determined using algorithms relating them to the velocity components. In this work, we propose an analytical flow phantom to evaluate these algorithms accurately. The Navier-Stokes equations are used to derive this flow phantom. The exact solution of these equations obtains analytical expression for the flow characteristics inside the domain. Features such as pulsatility, incompressibility and viscosity of flow are included in a three-dimensional domain. The velocity domain of the resulted system is presented as reference images. These images could be employed to evaluate the performance of different flow characteristic algorithms. In this study, we also present some applications of the obtained phantom. The calculation of pressure domain from velocity data, volumetric flow rate, wall shear stress and particle trace are the characteristics whose algorithms are evaluated here. We also present the application of this phantom in the analysis of noisy and low-resolution images. The presented phantom can be considered as a benchmark test to compare the accuracy of different flow characteristic algorithms.