Sample records for subgrid scale closure

  1. A nonlinear structural subgrid-scale closure for compressible MHD. I. Derivation and energy dissipation properties

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    Vlaykov, Dimitar G., E-mail: [Institut für Astrophysik, Universität Göttingen, Friedrich-Hund-Platz 1, D-37077 Göttingen (Germany); Max-Planck-Institut für Dynamik und Selbstorganisation, Am Faßberg 17, D-37077 Göttingen (Germany); Grete, Philipp [Institut für Astrophysik, Universität Göttingen, Friedrich-Hund-Platz 1, D-37077 Göttingen (Germany); Max-Planck-Institut für Sonnensystemforschung, Justus-von-Liebig-Weg 3, D-37077 Göttingen (Germany); Schmidt, Wolfram [Hamburger Sternwarte, Universität Hamburg, Gojenbergsweg 112, D-21029 Hamburg (Germany); Schleicher, Dominik R. G. [Departamento de Astronomía, Facultad Ciencias Físicas y Matemáticas, Universidad de Concepción, Av. Esteban Iturra s/n Barrio Universitario, Casilla 160-C (Chile)


    Compressible magnetohydrodynamic (MHD) turbulence is ubiquitous in astrophysical phenomena ranging from the intergalactic to the stellar scales. In studying them, numerical simulations are nearly inescapable, due to the large degree of nonlinearity involved. However, the dynamical ranges of these phenomena are much larger than what is computationally accessible. In large eddy simulations (LESs), the resulting limited resolution effects are addressed explicitly by introducing to the equations of motion additional terms associated with the unresolved, subgrid-scale dynamics. This renders the system unclosed. We derive a set of nonlinear structural closures for the ideal MHD LES equations with particular emphasis on the effects of compressibility. The closures are based on a gradient expansion of the finite-resolution operator [W. K. Yeo (CUP, 1993)] and require no assumptions about the nature of the flow or magnetic field. Thus, the scope of their applicability ranges from the sub- to the hyper-sonic and -Alfvénic regimes. The closures support spectral energy cascades both up and down-scale, as well as direct transfer between kinetic and magnetic resolved and unresolved energy budgets. They implicitly take into account the local geometry, and in particular, the anisotropy of the flow. Their properties are a priori validated in Paper II [P. Grete et al., Phys. Plasmas 23, 062317 (2016)] against alternative closures available in the literature with respect to a wide range of simulation data of homogeneous and isotropic turbulence.

  2. A nonlinear structural subgrid-scale closure for compressible MHD Part II: a priori comparison on turbulence simulation data

    CERN Document Server

    Grete, P; Schmidt, W; Schleicher, D R G


    Even though compressible plasma turbulence is encountered in many astrophysical phenomena, its effect is often not well understood. Furthermore, direct numerical simulations are typically not able to reach the extreme parameters of these processes. For this reason, large-eddy simulations (LES), which only simulate large and intermediate scales directly, are employed. The smallest, unresolved scales and the interactions between small and large scales are introduced by means of a subgrid-scale (SGS) model. We propose and verify a new set of nonlinear SGS closures for future application as an SGS model in LES of compressible magnetohydrodynamics (MHD). We use 15 simulations (without explicit SGS model) of forced, isotropic, homogeneous turbulence with varying sonic Mach number $\\mathrm{M_s} = 0.2$ to $20$ as reference data for the most extensive \\textit{a priori} tests performed so far in literature. In these tests we explicitly filter the reference data and compare the performance of the new closures against th...

  3. A nonlinear structural subgrid-scale closure for compressible MHD Part I: derivation and energy dissipation properties

    CERN Document Server

    Vlaykov, Dimitar G; Schmidt, Wolfram; Schleicher, Dominik R G


    Compressible magnetohydrodynamic (MHD) turbulence is ubiquitous in astrophysical phenomena ranging from the intergalactic to the stellar scales. In studying them, numerical simulations are nearly inescapable, due to the large degree of nonlinearity involved. However the dynamical ranges of these phenomena are much larger than what is computationally accessible. In large eddy simulations (LES), the resulting limited resolution effects are addressed explicitly by introducing to the equations of motion additional terms associated with the unresolved, subgrid-scale (SGS) dynamics. This renders the system unclosed. We derive a set of nonlinear structural closures for the ideal MHD LES equations with particular emphasis on the effects of compressibility. The closures are based on a gradient expansion of the finite-resolution operator (W.K. Yeo CUP 1993, ed. Galperin & Orszag) and require no assumptions about the nature of the flow or magnetic field. Thus the scope of their applicability ranges from the sub- to ...

  4. Assessment of sub-grid scale dispersion closure with regularized deconvolution method in a particle-laden turbulent jet (United States)

    Wang, Qing; Zhao, Xinyu; Ihme, Matthias


    Particle-laden turbulent flows are important in numerous industrial applications, such as spray combustion engines, solar energy collectors etc. It is of interests to study this type of flows numerically, especially using large-eddy simulations (LES). However, capturing the turbulence-particle interaction in LES remains challenging due to the insufficient representation of the effect of sub-grid scale (SGS) dispersion. In the present work, a closure technique for the SGS dispersion using regularized deconvolution method (RDM) is assessed. RDM was proposed as the closure for the SGS dispersion in a counterflow spray that is studied numerically using finite difference method on a structured mesh. A presumed form of LES filter is used in the simulations. In the present study, this technique has been extended to finite volume method with an unstructured mesh, where no presumption on the filter form is required. The method is applied to a series of particle-laden turbulent jets. Parametric analyses of the model performance are conducted for flows with different Stokes numbers and Reynolds numbers. The results from LES will be compared against experiments and direct numerical simulations (DNS).

  5. Simple subgrid scale stresses models for homogeneous isotropic turbulence (United States)

    Aupoix, B.; Cousteix, J.

    Large eddy simulations employing the filtering of Navier-Stokes equations highlight stresses, related to the interaction between large scales below the cut and small scales above it, which have been designated 'subgrid scale stresses'. Their effects include both the energy flux through the cut and a component of viscous diffusion. The eddy viscosity introduced in the subgrid scale models which give the correct energy flux through the cut by comparison with spectral closures is shown to depend only on the small scales. The Smagorinsky (1963) model can only be obtained if the cut lies in the middle of the inertial range. A novel model which takes the small scales into account statistically, and includes the effects of viscosity, is proposed and compared with classical models for the Comte-Bellot and Corrsin (1971) experiment.

  6. Statistical dynamical subgrid-scale parameterizations for geophysical flows

    Energy Technology Data Exchange (ETDEWEB)

    O' Kane, T J; Frederiksen, J S [Centre for Australian Weather and Climate Research, Bureau of Meteorology, 700 Collins St, Docklands, Melbourne, VIC (Australia) and CSIRO Marine and Atmospheric Research, Aspendale, VIC (Australia)], E-mail:


    Simulations of both atmospheric and oceanic circulations at given finite resolutions are strongly dependent on the form and strengths of the dynamical subgrid-scale parameterizations (SSPs) and in particular are sensitive to subgrid-scale transient eddies interacting with the retained scale topography and the mean flow. In this paper, we present numerical results for SSPs of the eddy-topographic force, stochastic backscatter, eddy viscosity and eddy-mean field interaction using an inhomogeneous statistical turbulence model based on a quasi-diagonal direct interaction approximation (QDIA). Although the theoretical description on which our model is based is for general barotropic flows, we specifically focus on global atmospheric flows where large-scale Rossby waves are present. We compare and contrast the closure-based results with an important earlier heuristic SSP of the eddy-topographic force, based on maximum entropy or statistical canonical equilibrium arguments, developed specifically for general ocean circulation models (Holloway 1992 J. Phys. Oceanogr. 22 1033-46). Our results demonstrate that where strong zonal flows and Rossby waves are present, such as in the atmosphere, maximum entropy arguments are insufficient to accurately parameterize the subgrid contributions due to eddy-eddy, eddy-topographic and eddy-mean field interactions. We contrast our atmospheric results with findings for the oceans. Our study identifies subgrid-scale interactions that are currently not parameterized in numerical atmospheric climate models, which may lead to systematic defects in the simulated circulations.

  7. Sub-Grid Scale Plume Modeling

    Directory of Open Access Journals (Sweden)

    Greg Yarwood


    Full Text Available Multi-pollutant chemical transport models (CTMs are being routinely used to predict the impacts of emission controls on the concentrations and deposition of primary and secondary pollutants. While these models have a fairly comprehensive treatment of the governing atmospheric processes, they are unable to correctly represent processes that occur at very fine scales, such as the near-source transport and chemistry of emissions from elevated point sources, because of their relatively coarse horizontal resolution. Several different approaches have been used to address this limitation, such as using fine grids, adaptive grids, hybrid modeling, or an embedded sub-grid scale plume model, i.e., plume-in-grid (PinG modeling. In this paper, we first discuss the relative merits of these various approaches used to resolve sub-grid scale effects in grid models, and then focus on PinG modeling which has been very effective in addressing the problems listed above. We start with a history and review of PinG modeling from its initial applications for ozone modeling in the Urban Airshed Model (UAM in the early 1980s using a relatively simple plume model, to more sophisticated and state-of-the-science plume models, that include a full treatment of gas-phase, aerosol, and cloud chemistry, embedded in contemporary models such as CMAQ, CAMx, and WRF-Chem. We present examples of some typical results from PinG modeling for a variety of applications, discuss the implications of PinG on model predictions of source attribution, and discuss possible future developments and applications for PinG modeling.

  8. Importance of subgrid-scale parameterization in numerical simulations of lake circulation (United States)

    Wang, Yongqi

    Two subgrid-scale modeling techniques--Smagorinsky's postulation for the horizontal eddy viscosity and the Mellor-Yamada level-2 model for the vertical eddy viscosity--are applied as turbulence closure conditions to numerical simulations of resolved-scale baroclinic lake circulations. The use of the total variation diminishing (TVD) technique in the numerical treatment of the advection terms in the governing equations depresses numerical diffusion to an acceptably low level and makes stable numerical performances possible with small eddy viscosities resulting from the turbulence closure parameterizations. The results show that, with regard to the effect of an external wind stress, the vertical turbulent mixing is mainly restricted to the topmost epilimnion with the order of magnitude for the vertical eddy viscosity of 10 -3 m 2 s -1, whilst the horizontal turbulent mixing may reach a somewhat deeper zone with an order of magnitude for the horizontal eddy viscosity of 0.1-1 m 2 s -1. Their spatial and temporal variations and influences on numerical results are significant. A comparison with prescribed constant eddy viscosities clearly shows the importance of subgrid-scale closures on resolved-scale flows in the lake circulation simulation. A predetermination of the eddy viscosities is inappropriate and should be abandoned. Their values must be determined by suitable subgrid-scale closure techniques.

  9. Modeling Subgrid Scale Droplet Deposition in Multiphase-CFD (United States)

    Agostinelli, Giulia; Baglietto, Emilio


    The development of first-principle-based constitutive equations for the Eulerian-Eulerian CFD modeling of annular flow is a major priority to extend the applicability of multiphase CFD (M-CFD) across all two-phase flow regimes. Two key mechanisms need to be incorporated in the M-CFD framework, the entrainment of droplets from the liquid film, and their deposition. Here we focus first on the aspect of deposition leveraging a separate effects approach. Current two-field methods in M-CFD do not include appropriate local closures to describe the deposition of droplets in annular flow conditions. As many integral correlations for deposition have been proposed for lumped parameters methods applications, few attempts exist in literature to extend their applicability to CFD simulations. The integral nature of the approach limits its applicability to fully developed flow conditions, without geometrical or flow variations, therefore negating the scope of CFD application. A new approach is proposed here that leverages local quantities to predict the subgrid-scale deposition rate. The methodology is first tested into a three-field approach CFD model.

  10. Stochastic fields method for sub-grid scale emission heterogeneity in mesoscale atmospheric dispersion models

    Directory of Open Access Journals (Sweden)

    M. Cassiani


    Full Text Available The stochastic fields method for turbulent reacting flows has been applied to the issue of sub-grid scale emission heterogeneity in a mesoscale model. This method is a solution technique for the probability density function (PDF transport equation and can be seen as a straightforward extension of currently used mesoscale dispersion models. It has been implemented in an existing mesoscale model and the results are compared with Large-Eddy Simulation (LES data devised to test specifically the effect of sub-grid scale emission heterogeneity on boundary layer concentration fluctuations. The sub-grid scale emission variability is assimilated in the model as a PDF of the emissions. The stochastic fields method shows excellent agreement with the LES data without adjustment of the constants used in the mesoscale model. The stochastic fields method is a stochastic solution of the transport equations for the concentration PDF of dispersing scalars, therefore it possesses the ability to handle chemistry of any complexity without the need to introduce additional closures for the high order statistics of chemical species. This study shows for the first time the feasibility of applying this method to mesoscale chemical transport models.

  11. Lagrangian scheme to model subgrid-scale mixing and spreading in heterogeneous porous media (United States)

    Herrera, P. A.; Cortínez, J. M.; Valocchi, A. J.


    Small-scale heterogeneity of permeability controls spreading, dilution, and mixing of solute plumes at large scale. However, conventional numerical simulations of solute transport are unable to resolve scales of heterogeneity below the grid scale. We propose a Lagrangian numerical approach to implement closure models to account for subgrid-scale spreading and mixing in Darcy-scale numerical simulations of solute transport in mildly heterogeneous porous media. The novelty of the proposed approach is that it considers two different dispersion coefficients to account for advective spreading mechanisms and local-scale dispersion. Using results of benchmark numerical simulations, we demonstrate that the proposed approach is able to model subgrid-scale spreading and mixing provided there is a correct choice of block-scale dispersion coefficient. We also demonstrate that for short travel times it is only possible to account for spreading or mixing using a single block-scale dispersion coefficient. Moreover, we show that it is necessary to use time-dependent dispersion coefficients to obtain correct mixing rates. On the contrary, for travel times that are large in comparison to the typical dispersive time scale, it is possible to use a single expression to compute the block-dispersion coefficient, which is equal to the asymptotic limit of the block-scale macrodispersion coefficient proposed by Rubin et al. (1999). Our approach provides a flexible and efficient way to model subgrid-scale mixing in numerical models of large-scale solute transport in heterogeneous aquifers. We expect that these findings will help to better understand the applicability of the advection-dispersion-equation (ADE) to simulate solute transport at the Darcy scale in heterogeneous porous media.

  12. Subgrid-scale turbulence in shock-boundary layer flows (United States)

    Jammalamadaka, Avinash; Jaberi, Farhad


    Data generated by direct numerical simulation (DNS) for a Mach 2.75 zero-pressure gradient turbulent boundary layer interacting with shocks of different intensities are used for a priori analysis of subgrid-scale (SGS) turbulence and various terms in the compressible filtered Navier-Stokes equations. The numerical method used for DNS is based on a hybrid scheme that uses a non-dissipative central scheme in the shock-free turbulent regions and a robust monotonicity-preserving scheme in the shock regions. The behavior of SGS stresses and their components, namely Leonard, Cross and Reynolds components, is examined in various regions of the flow for different shock intensities and filter widths. The backscatter in various regions of the flow is found to be significant only instantaneously, while the ensemble-averaged statistics indicate no significant backscatter. The budgets for the SGS kinetic energy equation are examined for a better understanding of shock-tubulence interactions at the subgrid level and also with the aim of providing useful information for one-equation LES models. A term-by-term analysis of SGS terms in the filtered total energy equation indicate that while each term in this equation is significant by itself, the net contribution by all of them is relatively small. This observation is consistent with our a posteriori analysis.

  13. A priori study of subgrid-scale flux of a passive scalar in isotropic homogeneous turbulence

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    Chumakov, Sergei [Los Alamos National Laboratory


    We perform a direct numerical simulation (DNS) of forced homogeneous isotropic turbulence with a passive scalar that is forced by mean gradient. The DNS data are used to study the properties of subgrid-scale flux of a passive scalar in the framework of large eddy simulation (LES), such as alignment trends between the flux, resolved, and subgrid-scale flow structures. It is shown that the direction of the flux is strongly coupled with the subgrid-scale stress axes rather than the resolved flow quantities such as strain, vorticity, or scalar gradient. We derive an approximate transport equation for the subgrid-scale flux of a scalar and look at the relative importance of the terms in the transport equation. A particular form of LES tensor-viscosity model for the scalar flux is investigated, which includes the subgrid-scale stress. Effect of different models for the subgrid-scale stress on the model for the subgrid-scale flux is studied.

  14. Exploring nonlinear subgrid-scale models and new characteristic length scales for large-eddy simulation

    NARCIS (Netherlands)

    Silvis, Maurits H.; Trias, F. Xavier; Abkar, M.; Bae, H.J.; Lozano-Duran, A.; Verstappen, R.W.C.P.; Moin, Parviz; Urzay, Javier


    We study subgrid-scale modeling for large-eddy simulation of anisotropic turbulent flows on anisotropic grids. In particular, we show how the addition of a velocity-gradient-based nonlinear model term to an eddy viscosity model provides a better representation of energy transfer. This is shown to

  15. Physical consistency of subgrid-scale models for large-eddy simulation of incompressible turbulent flows

    CERN Document Server

    Silvis, Maurits H; Verstappen, Roel


    We study the construction of subgrid-scale models for large-eddy simulation of incompressible turbulent flows. In particular, we aim to consolidate a systematic approach of constructing subgrid-scale models, based on the idea that it is desirable that subgrid-scale models are consistent with the properties of the Navier-Stokes equations and the turbulent stresses. To that end, we first discuss in detail the symmetries of the Navier-Stokes equations, and the near-wall scaling behavior, realizability and dissipation properties of the turbulent stresses. We furthermore summarize the requirements that subgrid-scale models have to satisfy in order to preserve these important mathematical and physical properties. In this fashion, a framework of model constraints arises that we apply to analyze the behavior of a number of existing subgrid-scale models that are based on the local velocity gradient. We show that these subgrid-scale models do not satisfy all the desired properties, after which we explain that this is p...

  16. Evapotranspiration and cloud variability at regional sub-grid scales (United States)

    Vila-Guerau de Arellano, Jordi; Sikma, Martin; Pedruzo-Bagazgoitia, Xabier; van Heerwaarden, Chiel; Hartogensis, Oscar; Ouwersloot, Huug


    In regional and global models uncertainties arise due to our incomplete understanding of the coupling between biochemical and physical processes. Representing their impact depends on our ability to calculate these processes using physically sound parameterizations, since they are unresolved at scales smaller than the grid size. More specifically over land, the coupling between evapotranspiration, turbulent transport of heat and moisture, and clouds lacks a combined representation to take these sub-grid scales interactions into account. Our approach is based on understanding how radiation, surface exchange, turbulent transport and moist convection are interacting from the leaf- to the cloud scale. We therefore place special emphasis on plant stomatal aperture as the main regulator of CO2-assimilation and water transpiration, a key source of moisture source to the atmosphere. Plant functionality is critically modulated by interactions with atmospheric conditions occurring at very short spatiotemporal scales such as cloud radiation perturbations or water vapour turbulent fluctuations. By explicitly resolving these processes, the LES (large-eddy simulation) technique is enabling us to characterize and better understand the interactions between canopies and the local atmosphere. This includes the adaption time of vegetation to rapid changes in atmospheric conditions driven by turbulence or the presence of cumulus clouds. Our LES experiments are based on explicitly coupling the diurnal atmospheric dynamics to a plant physiology model. Our general hypothesis is that different partitioning of direct and diffuse radiation leads to different responses of the vegetation. As a result there are changes in the water use efficiencies and shifts in the partitioning of sensible and latent heat fluxes under the presence of clouds. Our presentation is as follows. First, we discuss the ability of LES to reproduce the surface energy balance including photosynthesis and CO2 soil

  17. The subgrid-scale scalar variance under supercritical pressure conditions (United States)

    Masi, Enrica; Bellan, Josette


    To model the subgrid-scale (SGS) scalar variance under supercritical-pressure conditions, an equation is first derived for it. This equation is considerably more complex than its equivalent for atmospheric-pressure conditions. Using a previously created direct numerical simulation (DNS) database of transitional states obtained for binary-species systems in the context of temporal mixing layers, the activity of terms in this equation is evaluated, and it is found that some of these new terms have magnitude comparable to that of governing terms in the classical equation. Most prominent among these new terms are those expressing the variation of diffusivity with thermodynamic variables and Soret terms having dissipative effects. Since models are not available for these new terms that would enable solving the SGS scalar variance equation, the adopted strategy is to directly model the SGS scalar variance. Two models are investigated for this quantity, both developed in the context of compressible flows. The first one is based on an approximate deconvolution approach and the second one is a gradient-like model which relies on a dynamic procedure using the Leonard term expansion. Both models are successful in reproducing the SGS scalar variance extracted from the filtered DNS database, and moreover, when used in the framework of a probability density function (PDF) approach in conjunction with the β-PDF, they excellently reproduce a filtered quantity which is a function of the scalar. For the dynamic model, the proportionality coefficient spans a small range of values through the layer cross-stream coordinate, boding well for the stability of large eddy simulations using this model.

  18. Numerical dissipation vs. subgrid-scale modelling for large eddy simulation (United States)

    Dairay, Thibault; Lamballais, Eric; Laizet, Sylvain; Vassilicos, John Christos


    This study presents an alternative way to perform large eddy simulation based on a targeted numerical dissipation introduced by the discretization of the viscous term. It is shown that this regularisation technique is equivalent to the use of spectral vanishing viscosity. The flexibility of the method ensures high-order accuracy while controlling the level and spectral features of this purely numerical viscosity. A Pao-like spectral closure based on physical arguments is used to scale this numerical viscosity a priori. It is shown that this way of approaching large eddy simulation is more efficient and accurate than the use of the very popular Smagorinsky model in standard as well as in dynamic version. The main strength of being able to correctly calibrate numerical dissipation is the possibility to regularise the solution at the mesh scale. Thanks to this property, it is shown that the solution can be seen as numerically converged. Conversely, the two versions of the Smagorinsky model are found unable to ensure regularisation while showing a strong sensitivity to numerical errors. The originality of the present approach is that it can be viewed as implicit large eddy simulation, in the sense that the numerical error is the source of artificial dissipation, but also as explicit subgrid-scale modelling, because of the equivalence with spectral viscosity prescribed on a physical basis.

  19. A dynamic subgrid scale model for Large Eddy Simulations based on the Mori-Zwanzig formalism (United States)

    Parish, Eric J.; Duraisamy, Karthik


    The development of reduced models for complex multiscale problems remains one of the principal challenges in computational physics. The optimal prediction framework of Chorin et al. [1], which is a reformulation of the Mori-Zwanzig (M-Z) formalism of non-equilibrium statistical mechanics, provides a framework for the development of mathematically-derived reduced models of dynamical systems. Several promising models have emerged from the optimal prediction community and have found application in molecular dynamics and turbulent flows. In this work, a new M-Z-based closure model that addresses some of the deficiencies of existing methods is developed. The model is constructed by exploiting similarities between two levels of coarse-graining via the Germano identity of fluid mechanics and by assuming that memory effects have a finite temporal support. The appeal of the proposed model, which will be referred to as the 'dynamic-MZ-τ' model, is that it is parameter-free and has a structural form imposed by the mathematics of the coarse-graining process (rather than the phenomenological assumptions made by the modeler, such as in classical subgrid scale models). To promote the applicability of M-Z models in general, two procedures are presented to compute the resulting model form, helping to bypass the tedious error-prone algebra that has proven to be a hindrance to the construction of M-Z-based models for complex dynamical systems. While the new formulation is applicable to the solution of general partial differential equations, demonstrations are presented in the context of Large Eddy Simulation closures for the Burgers equation, decaying homogeneous turbulence, and turbulent channel flow. The performance of the model and validity of the underlying assumptions are investigated in detail.

  20. Multifractal subgrid-scale modeling within a variational multiscale method for large-eddy simulation of turbulent flow (United States)

    Rasthofer, U.; Gravemeier, V.


    Multifractal subgrid-scale modeling within a variational multiscale method is proposed for large-eddy simulation of turbulent flow. In the multifractal subgrid-scale modeling approach, the subgrid-scale velocity is evaluated from a multifractal description of the subgrid-scale vorticity, which is based on the multifractal scale similarity of gradient fields in turbulent flow. The multifractal subgrid-scale modeling approach is integrated into a variational multiscale formulation, which constitutes a new application of the variational multiscale concept. A focus of this study is on the application of the multifractal subgrid-scale modeling approach to wall-bounded turbulent flow. Therefore, a near-wall limit of the multifractal subgrid-scale modeling approach is derived in this work. The novel computational approach of multifractal subgrid-scale modeling within a variational multiscale formulation is applied to turbulent channel flow at various Reynolds numbers, turbulent flow over a backward-facing step and turbulent flow past a square-section cylinder, which are three of the most important and widely-used benchmark examples for wall-bounded turbulent flow. All results presented in this study confirm a very good performance of the proposed method. Compared to a dynamic Smagorinsky model and a residual-based variational multiscale method, improved results are obtained. Moreover, it is demonstrated that the subgrid-scale energy transfer incorporated by the proposed method very well approximates the expected energy transfer as obtained from appropriately filtered direct numerical simulation data. The computational cost is notably reduced compared to a dynamic Smagorinsky model and only marginally increased compared to a residual-based variational multiscale method.

  1. Subgrid-scale models for large-eddy simulation of rotating turbulent channel flows (United States)

    Silvis, Maurits H.; Bae, Hyunji Jane; Trias, F. Xavier; Abkar, Mahdi; Moin, Parviz; Verstappen, Roel


    We aim to design subgrid-scale models for large-eddy simulation of rotating turbulent flows. Rotating turbulent flows form a challenging test case for large-eddy simulation due to the presence of the Coriolis force. The Coriolis force conserves the total kinetic energy while transporting it from small to large scales of motion, leading to the formation of large-scale anisotropic flow structures. The Coriolis force may also cause partial flow laminarization and the occurrence of turbulent bursts. Many subgrid-scale models for large-eddy simulation are, however, primarily designed to parametrize the dissipative nature of turbulent flows, ignoring the specific characteristics of transport processes. We, therefore, propose a new subgrid-scale model that, in addition to the usual dissipative eddy viscosity term, contains a nondissipative nonlinear model term designed to capture transport processes, such as those due to rotation. We show that the addition of this nonlinear model term leads to improved predictions of the energy spectra of rotating homogeneous isotropic turbulence as well as of the Reynolds stress anisotropy in spanwise-rotating plane-channel flows. This work is financed by the Netherlands Organisation for Scientific Research (NWO) under Project Number 613.001.212.

  2. Stochastic fields method for sub-grid scale emission heterogeneity in mesoscale atmospheric dispersion models


    M. Cassiani; Vinuesa, J.F.; Galmarini, S.; Denby, B


    The stochastic fields method for turbulent reacting flows has been applied to the issue of sub-grid scale emission heterogeneity in a mesoscale model. This method is a solution technique for the probability density function (PDF) transport equation and can be seen as a straightforward extension of currently used mesoscale dispersion models. It has been implemented in an existing mesoscale model and the results are compared with Large-Eddy Simulation (LES) data devised to test specifically the...

  3. Subgrid-scale stresses and scalar fluxes constructed by the multi-scale turnover Lagrangian map (United States)

    AL-Bairmani, Sukaina; Li, Yi; Rosales, Carlos; Xie, Zheng-tong


    The multi-scale turnover Lagrangian map (MTLM) [C. Rosales and C. Meneveau, "Anomalous scaling and intermittency in three-dimensional synthetic turbulence," Phys. Rev. E 78, 016313 (2008)] uses nested multi-scale Lagrangian advection of fluid particles to distort a Gaussian velocity field and, as a result, generate non-Gaussian synthetic velocity fields. Passive scalar fields can be generated with the procedure when the fluid particles carry a scalar property [C. Rosales, "Synthetic three-dimensional turbulent passive scalar fields via the minimal Lagrangian map," Phys. Fluids 23, 075106 (2011)]. The synthetic fields have been shown to possess highly realistic statistics characterizing small scale intermittency, geometrical structures, and vortex dynamics. In this paper, we present a study of the synthetic fields using the filtering approach. This approach, which has not been pursued so far, provides insights on the potential applications of the synthetic fields in large eddy simulations and subgrid-scale (SGS) modelling. The MTLM method is first generalized to model scalar fields produced by an imposed linear mean profile. We then calculate the subgrid-scale stress, SGS scalar flux, SGS scalar variance, as well as related quantities from the synthetic fields. Comparison with direct numerical simulations (DNSs) shows that the synthetic fields reproduce the probability distributions of the SGS energy and scalar dissipation rather well. Related geometrical statistics also display close agreement with DNS results. The synthetic fields slightly under-estimate the mean SGS energy dissipation and slightly over-predict the mean SGS scalar variance dissipation. In general, the synthetic fields tend to slightly under-estimate the probability of large fluctuations for most quantities we have examined. Small scale anisotropy in the scalar field originated from the imposed mean gradient is captured. The sensitivity of the synthetic fields on the input spectra is assessed by

  4. A Physically Based Horizontal Subgrid-scale Turbulent Mixing Parameterization for the Convective Boundary Layer in Mesoscale Models (United States)

    Zhou, Bowen; Xue, Ming; Zhu, Kefeng


    Compared to the representation of vertical turbulent mixing through various PBL schemes, the treatment of horizontal turbulence mixing in the boundary layer within mesoscale models, with O(10) km horizontal grid spacing, has received much less attention. In mesoscale models, subgrid-scale horizontal fluxes most often adopt the gradient-diffusion assumption. The horizontal mixing coefficients are usually set to a constant, or through the 2D Smagorinsky formulation, or in some cases based on the 1.5-order turbulence kinetic energy (TKE) closure. In this work, horizontal turbulent mixing parameterizations using physically based characteristic velocity and length scales are proposed for the convective boundary layer based on analysis of a well-resolved, wide-domain large-eddy simulation (LES). The proposed schemes involve different levels of sophistication. The first two schemes can be used together with first-order PBL schemes, while the third uses TKE to define its characteristic velocity scale and can be used together with TKE-based higher-order PBL schemes. The current horizontal mixing formulations are also assessed a priori through the filtered LES results to illustrate their limitations. The proposed parameterizations are tested a posteriori in idealized simulations of turbulent dispersion of a passive scalar. Comparisons show improved horizontal dispersion by the proposed schemes, and further demonstrate the weakness of the current schemes.

  5. An explicit relaxation filtering framework based upon Perona-Malik anisotropic diffusion for shock capturing and subgrid scale modeling of Burgers turbulence

    CERN Document Server

    Maulik, Romit


    In this paper, we introduce a relaxation filtering closure approach to account for subgrid scale effects in explicitly filtered large eddy simulations using the concept of anisotropic diffusion. We utilize the Perona-Malik diffusion model and demonstrate its shock capturing ability and spectral performance for solving the Burgers turbulence problem, which is a simplified prototype for more realistic turbulent flows showing the same quadratic nonlinearity. Our numerical assessments present the behavior of various diffusivity functions in conjunction with a detailed sensitivity analysis with respect to the free modeling parameters. In comparison to direct numerical simulation (DNS) and under-resolved DNS results, we find that the proposed closure model is efficient in the prevention of energy accumulation at grid cut-off and is also adept at preventing any possible spurious numerical oscillations due to shock formation under the optimal parameter choices. In contrast to other relaxation filtering approaches, it...

  6. Resolution-dependent behavior of subgrid-scale vertical transport in the Zhang-McFarlane convection parameterization (United States)

    Xiao, Heng; Gustafson, William I.; Hagos, Samson M.; Wu, Chien-Ming; Wan, Hui


    To better understand the behavior of quasi-equilibrium-based convection parameterizations at higher resolution, we use a diagnostic framework to examine the resolution-dependence of subgrid-scale vertical transport of moist static energy as parameterized by the Zhang-McFarlane convection parameterization (ZM). Grid-scale input to ZM is supplied by coarsening output from cloud-resolving model (CRM) simulations onto subdomains ranging in size from 8 × 8 to 256 × 256 km2. Then the ZM-based parameterization of vertical transport of moist static energy for scales smaller than the subdomain size (w'h'>¯ZM) are compared to those directly calculated from the CRM simulations (w'h'>¯CRM) for different subdomain sizes. The ensemble mean w'h'>¯CRM decreases by more than half as the subdomain size decreases from 128 to 8 km across while w'h'>¯ZM decreases with subdomain size only for strong convection cases and increases for weaker cases. The resolution dependence of w'h'>¯ZM is determined by the positive-definite grid-scale tendency of convective available potential energy (CAPE) in the convective quasi-equilibrium (QE) closure. Further analysis shows the actual grid-scale tendency of CAPE (before taking the positive definite value) and w'h'>¯CRM behave very similarly as the subdomain size changes because they are both tied to grid-scale advective tendencies. We can improve the resolution dependence of w'h'>¯ZM significantly by averaging the grid-scale tendency of CAPE over an appropriately large area surrounding each subdomain before taking its positive definite value. Even though the ensemble mean w'h'>¯CRM decreases with increasing resolution, its variability increases dramatically. w'h'>¯ZM cannot capture such increase in the variability, suggesting the need for stochastic treatment of convection at relatively high spatial resolution (8 or 16 km).

  7. Evaluation of Subgrid-Scale Transport of Hydrometeors in a PDF-based Scheme using High-Resolution CRM Simulations (United States)

    Wong, M.; Ovchinnikov, M.; Wang, M.; Larson, V. E.


    In current climate models, the model resolution is too coarse to explicitly resolve deep convective systems. Parameterization schemes are therefore needed to represent the physical processes at the sub-grid scale. Recently, an approach based on assumed probability density functions (PDFs) has been developed to help unify the various parameterization schemes used in current global models. In particular, a unified parameterization scheme called the Cloud Layers Unified By Binormals (CLUBB) scheme has been developed and tested successfully for shallow boundary-layer clouds. CLUBB's implementation in the Community Atmosphere Model, version 5 (CAM5) is also being extended to treat deep convection cases, but parameterizing subgrid-scale vertical transport of hydrometeors remains a challenge. To investigate the roots of the problem and possible solutions, we generate a high-resolution benchmark simulation of a deep convection case using a cloud-resolving model (CRM) called System for Atmospheric Modeling (SAM). We use the high-resolution 3D CRM results to assess the prognostic and diagnostic higher-order moments in CLUBB that are in relation to the subgrid-scale transport of hydrometeors. We also analyze the heat and moisture budgets in terms of CLUBB variables from the SAM benchmark simulation. The results from this study will be used to devise a better representation of vertical subgrid-scale transport of hydrometeors by utilizing the sub-grid variability information from CLUBB.

  8. Effects of Implementing Subgrid-Scale Cloud-Radiation Interactions in a Regional Climate Model (United States)

    Herwehe, J. A.; Alapaty, K.; Otte, T.; Nolte, C. G.


    Interactions between atmospheric radiation, clouds, and aerosols are the most important processes that determine the climate and its variability. In regional scale models, when used at relatively coarse spatial resolutions (e.g., larger than 1 km), convective cumulus clouds need to be parameterized as subgrid-scale clouds. Like many groups, our regional climate modeling group at the EPA uses the Weather Research & Forecasting model (WRF) as a regional climate model (RCM). One of the findings from our RCM studies is that the summertime convective systems simulated by the WRF model are highly energetic, leading to excessive surface precipitation. We also found that the WRF model does not consider the interactions between convective clouds and radiation, thereby omitting an important process that drives the climate. Thus, the subgrid-scale cloudiness associated with convective clouds (from shallow cumuli to thunderstorms) does not exist and radiation passes through the atmosphere nearly unimpeded, potentially leading to overly energetic convection. This also has implications for air quality modeling systems that are dependent upon cloud properties from the WRF model, as the failure to account for subgrid-scale cloudiness can lead to problems such as the underrepresentation of aqueous chemistry processes within clouds and the overprediction of ozone from overactive photolysis. In an effort to advance the climate science of the cloud-aerosol-radiation (CAR) interactions in RCM systems, as a first step we have focused on linking the cumulus clouds with the radiation processes. To this end, our research group has implemented into WRF's Kain-Fritsch (KF) cumulus parameterization a cloudiness formulation that is widely used in global earth system models (e.g., CESM/CAM5). Estimated grid-scale cloudiness and associated condensate are adjusted to account for the subgrid clouds and then passed to WRF's Rapid Radiative Transfer Model - Global (RRTMG) radiation schemes to affect

  9. Improving sub-grid scale accuracy of boundary features in regional finite-difference models (United States)

    Panday, Sorab; Langevin, Christian D.


    As an alternative to grid refinement, the concept of a ghost node, which was developed for nested grid applications, has been extended towards improving sub-grid scale accuracy of flow to conduits, wells, rivers or other boundary features that interact with a finite-difference groundwater flow model. The formulation is presented for correcting the regular finite-difference groundwater flow equations for confined and unconfined cases, with or without Newton Raphson linearization of the nonlinearities, to include the Ghost Node Correction (GNC) for location displacement. The correction may be applied on the right-hand side vector for a symmetric finite-difference Picard implementation, or on the left-hand side matrix for an implicit but asymmetric implementation. The finite-difference matrix connectivity structure may be maintained for an implicit implementation by only selecting contributing nodes that are a part of the finite-difference connectivity. Proof of concept example problems are provided to demonstrate the improved accuracy that may be achieved through sub-grid scale corrections using the GNC schemes.

  10. Large eddy simulation of flow over a wall-mounted cube: Comparison of different semi dynamic subgrid scale models

    Directory of Open Access Journals (Sweden)

    M Nooroullahi


    Full Text Available In this paper the ability of different semi dynamic subgrid scale models for large eddy simulation was studied in a challenging test case. The semi dynamic subgrid scale models were examined in this investigation is Selective Structure model, Coherent structure model, Wall Adaptive Large Eddy model. The test case is a simulation of flow over a wall-mounted cube in a channel. The results of these models were compared to structure function model, dynamic models and experimental data at Reynolds number 40000. Results show that these semi dynamic models could improve the ability of numerical simulation in comparison with other models which use a constant coefficient for simulation of subgrid scale viscosity. In addition, these models don't have the instability problems of dynamic models.

  11. Parameterization of subgrid plume dilution for use in large-scale atmospheric simulations

    Directory of Open Access Journals (Sweden)

    A. D. Naiman


    Full Text Available A new model of plume dynamics has been developed for use as a subgrid model of plume dilution in a large-scale atmospheric simulation. The model uses mean wind, shear, and diffusion parameters derived from the local large-scale variables to advance the plume cross-sectional shape and area in time. Comparisons with a large eddy simulation of aircraft emission plume dynamics, with an analytical solution to the dynamics of a sheared Gaussian plume, and with measurements of aircraft exhaust plume dilution at cruise altitude show good agreement with these previous studies. We argue that the model also provides a reasonable approximation of line-shaped contrail dilution and give an example of how it can be applied in a global climate model.

  12. Closure for milliliter scale bioreactor (United States)

    Klein, David L.; Laidlaw, Robert D.; Andronaco, Gregory; Boyer, Stephen G.


    A closure for a microreactor includes a cap that is configured to be inserted into a well of the microreactor. The cap, or at least a portion of the cap, is compliant so as to form a seal with the well when the cap is inserted. The cap includes an aperture that provides an airway between the inside of the well to the external environment when the cap is inserted into the well. A porous plug is inserted in the aperture, e.g., either directly or in tube that extends through the aperture. The porous plug permits gas within the well to pass through the aperture while preventing liquids from passing through to reduce evaporation and preventing microbes from passing through to provide a sterile environment. A one-way valve may also be used to help control the environment in the well.

  13. Sub-grid scale models for discontinuous Galerkin methods based on the Mori-Zwanzig formalism (United States)

    Parish, Eric; Duraisamy, Karthk


    The optimal prediction framework of Chorin et al., which is a reformulation of the Mori-Zwanzig (M-Z) formalism of non-equilibrium statistical mechanics, provides a framework for the development of mathematically-derived closure models. The M-Z formalism provides a methodology to reformulate a high-dimensional Markovian dynamical system as a lower-dimensional, non-Markovian (non-local) system. In this lower-dimensional system, the effects of the unresolved scales on the resolved scales are non-local and appear as a convolution integral. The non-Markovian system is an exact statement of the original dynamics and is used as a starting point for model development. In this work, we investigate the development of M-Z-based closures model within the context of the Variational Multiscale Method (VMS). The method relies on a decomposition of the solution space into two orthogonal subspaces. The impact of the unresolved subspace on the resolved subspace is shown to be non-local in time and is modeled through the M-Z-formalism. The models are applied to hierarchical discontinuous Galerkin discretizations. Commonalities between the M-Z closures and conventional flux schemes are explored. This work was supported in part by AFOSR under the project ''LES Modeling of Non-local effects using Statistical Coarse-graining'' with Dr. Jean-Luc Cambier as the technical monitor.

  14. A priori study of subgrid-scale features in turbulent Rayleigh-Bénard convection (United States)

    Dabbagh, F.; Trias, F. X.; Gorobets, A.; Oliva, A.


    At the crossroad between flow topology analysis and turbulence modeling, a priori studies are a reliable tool to understand the underlying physics of the subgrid-scale (SGS) motions in turbulent flows. In this paper, properties of the SGS features in the framework of a large-eddy simulation are studied for a turbulent Rayleigh-Bénard convection (RBC). To do so, data from direct numerical simulation (DNS) of a turbulent air-filled RBC in a rectangular cavity of aspect ratio unity and π spanwise open-ended distance are used at two Rayleigh numbers R a ∈{1 08,1 010 } [Dabbagh et al., "On the evolution of flow topology in turbulent Rayleigh-Bénard convection," Phys. Fluids 28, 115105 (2016)]. First, DNS at Ra = 108 is used to assess the performance of eddy-viscosity models such as QR, Wall-Adapting Local Eddy-viscosity (WALE), and the recent S3PQR-models proposed by Trias et al. ["Building proper invariants for eddy-viscosity subgrid-scale models," Phys. Fluids 27, 065103 (2015)]. The outcomes imply that the eddy-viscosity modeling smoothes the coarse-grained viscous straining and retrieves fairly well the effect of the kinetic unfiltered scales in order to reproduce the coherent large scales. However, these models fail to approach the exact evolution of the SGS heat flux and are incapable to reproduce well the further dominant rotational enstrophy pertaining to the buoyant production. Afterwards, the key ingredients of eddy-viscosity, νt, and eddy-diffusivity, κt, are calculated a priori and revealed positive prevalent values to maintain a turbulent wind essentially driven by the mean buoyant force at the sidewalls. The topological analysis suggests that the effective turbulent diffusion paradigm and the hypothesis of a constant turbulent Prandtl number are only applicable in the large-scale strain-dominated areas in the bulk. It is shown that the bulk-dominated rotational structures of vortex-stretching (and its synchronous viscous dissipative structures) hold

  15. Convective kinetic energy equation under the mass-flux subgrid-scale parameterization (United States)

    Yano, Jun-Ichi


    The present paper originally derives the convective kinetic energy equation under mass-flux subgrid-scale parameterization in a formal manner based on the segmentally-constant approximation (SCA). Though this equation is long since presented by Arakawa and Schubert (1974), a formal derivation is not known in the literature. The derivation of this formulation is of increasing interests in recent years due to the fact that it can explain basic aspects of the convective dynamics such as discharge-recharge and transition from shallow to deep convection. The derivation is presented in two manners: (i) for the case that only the vertical component of the velocity is considered and (ii) the case that both the horizontal and vertical components are considered. The equation reduces to the same form as originally presented by Arakwa and Schubert in both cases, but with the energy dissipation term defined differently. In both cases, nevertheless, the energy "dissipation" (loss) term consists of the three principal contributions: (i) entrainment-detrainment, (ii) outflow from top of convection, and (iii) pressure effects. Additionally, inflow from the bottom of convection contributing to a growth of convection is also formally counted as a part of the dissipation term. The eddy dissipation is also included for a completeness. The order-of-magnitude analysis shows that the convective kinetic energy "dissipation" is dominated by the pressure effects, and it may be approximately described by Rayleigh damping with a constant time scale of the order of 102-103 s. The conclusion is also supported by a supplementary analysis of a cloud-resolving model (CRM) simulation. The Appendix discusses how the loss term ("dissipation") of the convective kinetic energy is qualitatively different from the conventional eddy-dissipation process found in turbulent flows.

  16. A scale-aware subgrid model for quasi-geostrophic turbulence (United States)

    Bachman, Scott D.; Fox-Kemper, Baylor; Pearson, Brodie


    This paper introduces two methods for dynamically prescribing eddy-induced diffusivity, advection, and viscosity appropriate for primitive equation models with resolutions permitting the forward potential enstrophy cascade of quasi-geostrophic dynamics, such as operational ocean models and high-resolution climate models with O>(25>) km horizontal resolution and finer. Where quasi-geostrophic dynamics fail (e.g., the equator, boundary layers, and deep convection), the method reverts to scalings based on a matched two-dimensional enstrophy cascade. A principle advantage is that these subgrid models are scale-aware, meaning that the model is suitable over a range of grid resolutions: from mesoscale grids that just permit baroclinic instabilities to grids below the submesoscale where ageostrophic effects dominate. Two approaches are presented here using Large Eddy Simulation (LES) techniques adapted for three-dimensional rotating, stratified turbulence. The simpler approach has one nondimensional parameter, Λ, which has an optimal value near 1. The second approach dynamically optimizes Λ during simulation using a test filter. The new methods are tested in an idealized scenario by varying the grid resolution, and their use improves the spectra of potential enstrophy and energy in comparison to extant schemes. The new methods keep the gridscale Reynolds and Péclet numbers near 1 throughout the domain, which confers robust numerical stability and minimal spurious diapycnal mixing. Although there are no explicit parameters in the dynamic approach, there is strong sensitivity to the choice of test filter. Designing test filters for heterogeneous ocean turbulence adds cost and uncertainty, and we find the dynamic method does not noticeably improve over setting Λ = 1.

  17. A Dynamic Subgrid Scale Model for Large Eddy Simulations Based on the Mori-Zwanzig Formalism

    CERN Document Server

    Parish, Eric J


    The development of reduced models for complex systems that lack scale separation remains one of the principal challenges in computational physics. The optimal prediction framework of Chorin et al., which is a reformulation of the Mori-Zwanzig (M-Z) formalism of non-equilibrium statistical mechanics, provides a methodology for the development of mathematically-derived reduced models of dynamical systems. Several promising models have emerged from the optimal prediction community and have found application in molecular dynamics and turbulent flows. In this work, a novel M-Z-based closure model that addresses some of the deficiencies of existing methods is developed. The model is constructed by exploiting similarities between two levels of coarse-graining via the Germano identity of fluid mechanics and by assuming that memory effects have a finite temporal support. The appeal of the proposed model, which will be referred to as the `dynamic-$\\tau$' model, is that it is parameter-free and has a structural form imp...

  18. Parameterization for subgrid-scale motion of ice-shelf calving fronts

    Directory of Open Access Journals (Sweden)

    T. Albrecht


    Full Text Available A parameterization for the motion of ice-shelf fronts on a Cartesian grid in finite-difference land-ice models is presented. The scheme prevents artificial thinning of the ice shelf at its edge, which occurs due to the finite resolution of the model. The intuitive numerical implementation diminishes numerical dispersion at the ice front and enables the application of physical boundary conditions to improve the calculation of stress and velocity fields throughout the ice-sheet-shelf system. Numerical properties of this subgrid modification are assessed in the Potsdam Parallel Ice Sheet Model (PISM-PIK for different geometries in one and two horizontal dimensions and are verified against an analytical solution in a flow-line setup.

  19. One-equation sub-grid scale (SGS) modelling for Euler-Euler large eddy simulation (EELES) of dispersed bubbly flow

    NARCIS (Netherlands)

    Niceno, B.; Dhotre, M.T.; Deen, N.G.


    In this work, we have presented a one-equation model for sub-grid scale (SGS) kinetic energy and applied it for an Euler-Euler large eddy simulation (EELES) of a bubble column reactor. The one-equation model for SGS kinetic energy shows improved predictions over the state-of-the-art dynamic

  20. On the Effect of an Anisotropy-Resolving Subgrid-Scale Model on Turbulent Vortex Motions (United States)


    expression coincides with the modified Leonard stress proposed by Ger- mano et al. (1991). In this model, the SGS turbulence energy kSGS may be evaluated as... mano subgridscale closure method. Phys. Fluids A, Vol. 4, pp. 633-635. Morinishi, Y. and Vasilyev, O.V. (2001), A recommended modification to the

  1. High-Resolution Global Modeling of the Effects of Subgrid-Scale Clouds and Turbulence on Precipitating Cloud Systems

    Energy Technology Data Exchange (ETDEWEB)

    Bogenschutz, Peter [National Center for Atmospheric Research, Boulder, CO (United States); Moeng, Chin-Hoh [National Center for Atmospheric Research, Boulder, CO (United States)


    The PI’s at the National Center for Atmospheric Research (NCAR), Chin-Hoh Moeng and Peter Bogenschutz, have primarily focused their time on the implementation of the Simplified-Higher Order Turbulence Closure (SHOC; Bogenschutz and Krueger 2013) to the Multi-scale Modeling Framework (MMF) global model and testing of SHOC on deep convective cloud regimes.

  2. Impact of Sub-grid Soil Textural Properties on Simulations of Hydrological Fluxes at the Continental Scale Mississippi River Basin (United States)

    Kumar, R.; Samaniego, L. E.; Livneh, B.


    Knowledge of soil hydraulic properties such as porosity and saturated hydraulic conductivity is required to accurately model the dynamics of near-surface hydrological processes (e.g. evapotranspiration and root-zone soil moisture dynamics) and provide reliable estimates of regional water and energy budgets. Soil hydraulic properties are commonly derived from pedo-transfer functions using soil textural information recorded during surveys, such as the fractions of sand and clay, bulk density, and organic matter content. Typically large scale land-surface models are parameterized using a relatively coarse soil map with little or no information on parametric sub-grid variability. In this study we analyze the impact of sub-grid soil variability on simulated hydrological fluxes over the Mississippi River Basin (≈3,240,000 km2) at multiple spatio-temporal resolutions. A set of numerical experiments were conducted with the distributed mesoscale hydrologic model (mHM) using two soil datasets: (a) the Digital General Soil Map of the United States or STATSGO2 (1:250 000) and (b) the recently collated Harmonized World Soil Database based on the FAO-UNESCO Soil Map of the World (1:5 000 000). mHM was parameterized with the multi-scale regionalization technique that derives distributed soil hydraulic properties via pedo-transfer functions and regional coefficients. Within the experimental framework, the 3-hourly model simulations were conducted at four spatial resolutions ranging from 0.125° to 1°, using meteorological datasets from the NLDAS-2 project for the time period 1980-2012. Preliminary results indicate that the model was able to capture observed streamflow behavior reasonably well with both soil datasets, in the major sub-basins (i.e. the Missouri, the Upper Mississippi, the Ohio, the Red, and the Arkansas). However, the spatio-temporal patterns of simulated water fluxes and states (e.g. soil moisture, evapotranspiration) from both simulations, showed marked

  3. Final Report. Evaluating the Climate Sensitivity of Dissipative Subgrid-Scale Mixing Processes and Variable Resolution in NCAR's Community Earth System Model

    Energy Technology Data Exchange (ETDEWEB)

    Jablonowski, Christiane [Univ. of Michigan, Ann Arbor, MI (United States)


    The goals of this project were to (1) assess and quantify the sensitivity and scale-dependency of unresolved subgrid-scale mixing processes in NCAR’s Community Earth System Model (CESM), and (2) to improve the accuracy and skill of forthcoming CESM configurations on modern cubed-sphere and variable-resolution computational grids. The research thereby contributed to the description and quantification of uncertainties in CESM’s dynamical cores and their physics-dynamics interactions.

  4. Large Eddy Simulation of an SD7003 Airfoil: Effects of Reynolds number and Subgrid-scale modeling (United States)

    Sarlak, Hamid


    This paper presents results of a series of numerical simulations in order to study aerodynamic characteristics of the low Reynolds number Selig-Donovan airfoil, SD7003. Large Eddy Simulation (LES) technique is used for all computations at chord-based Reynolds numbers 10,000, 24,000 and 60,000 and simulations have been performed to primarily investigate the role of sub-grid scale (SGS) modeling on the dynamics of flow generated over the airfoil, which has not been dealt with in great detail in the past. It is seen that simulations are increasingly getting influenced by SGS modeling with increasing the Reynolds number, and the effect is visible even at a relatively low chord-Reynolds number of 60,000. Among the tested models, the dynamic Smagorinsky gives the poorest predictions of the flow, with overprediction of lift and a larger separation on airfoils suction side. Among various models, the implicit LES offers closest pressure distribution predictions compared with literature.

  5. A new mixed subgrid-scale model for large eddy simulation of turbulent drag-reducing flows of viscoelastic fluids (United States)

    Li, Feng-Chen; Wang, Lu; Cai, Wei-Hua


    A mixed subgrid-scale (SGS) model based on coherent structures and temporal approximate deconvolution (MCT) is proposed for turbulent drag-reducing flows of viscoelastic fluids. The main idea of the MCT SGS model is to perform spatial filtering for the momentum equation and temporal filtering for the conformation tensor transport equation of turbulent flow of viscoelastic fluid, respectively. The MCT model is suitable for large eddy simulation (LES) of turbulent drag-reducing flows of viscoelastic fluids in engineering applications since the model parameters can be easily obtained. The LES of forced homogeneous isotropic turbulence (FHIT) with polymer additives and turbulent channel flow with surfactant additives based on MCT SGS model shows excellent agreements with direct numerical simulation (DNS) results. Compared with the LES results using the temporal approximate deconvolution model (TADM) for FHIT with polymer additives, this mixed SGS model MCT behaves better, regarding the enhancement of calculating parameters such as the Reynolds number. For scientific and engineering research, turbulent flows at high Reynolds numbers are expected, so the MCT model can be a more suitable model for the LES of turbulent drag-reducing flows of viscoelastic fluid with polymer or surfactant additives. Project supported by the China Postdoctoral Science Foundation (Grant No. 2011M500652), the National Natural Science Foundation of China (Grant Nos. 51276046 and 51206033), and the Specialized Research Fund for the Doctoral Program of Higher Education of China (Grant No. 20112302110020).

  6. Exploring the Limits of the Dynamic Procedure for Modeling Subgrid-Scale Stresses in LES of Inhomogeneous Flows. (United States)

    Le, A.-T.; Kim, J.; Coleman, G.


    One of the primary reasons dynamic subgrid-scale (SGS) models are more successful than those that are `hand-tuned' is thought to be their insensitivity to numerical and modeling parameters. Jiménez has recently demonstrated that large-eddy simulations (LES) of decaying isotropic turbulence using a dynamic Smagorinsky model yield correct decay rates -- even when the model is subjected to a range of artificial perturbations. The objective of the present study is to determine to what extent this `self-adjusting' feature of dynamic SGS models is found in LES of inhomogeneous flows. The effects of numerical and modeling parameters on the accuracy of LES solutions of fully developed and developing turbulent channel flow are studied, using a spectral code and various dynamic models (including those of Lilly et al. and Meneveau et al.); other modeling parameters tested include the filter-width ratio and the effective magnitude of the Smagorinsky coefficient. Numerical parameters include the form of the convective term and the type of test filter (sharp-cutoff versus tophat). The resulting LES statistics are found to be surprisingly sensitive to the various parameter choices, which implies that more care than is needed for homogeneous-flow simulations must be exercised when performing LES of inhomogeneous flows.

  7. Opening up closure. Semiotics across scales (United States)



    The dynamic emergence of new levels of organization in complex systems is related to the semiotic reorganization of discrete/continuous variety at the level below as continuous/discrete meaning for the level above. In this view both the semiotic and the dynamic closure of system levels is reopened to allow the development and evolution of greater complexity.

  8. Effect of Considering Sub-Grid Scale Uncertainties on the Forecasts of a High-Resolution Limited Area Ensemble Prediction System (United States)

    Kim, SeHyun; Kim, Hyun Mee


    The ensemble prediction system (EPS) is widely used in research and at operation center because it can represent the uncertainty of predicted atmospheric state and provide information of probabilities. The high-resolution (so-called "convection-permitting") limited area EPS can represent the convection and turbulence related to precipitation phenomena in more detail, but it is also much sensitive to small-scale or sub-grid scale processes. The convection and turbulence are represented using physical processes in the model and model errors occur due to sub-grid scale processes that were not resolved. This study examined the effect of considering sub-grid scale uncertainties using the high-resolution limited area EPS of the Korea Meteorological Administration (KMA). The developed EPS has horizontal resolution of 3 km and 12 ensemble members. The initial and boundary conditions were provided by the global model. The Random Parameters (RP) scheme was used to represent sub-grid scale uncertainties. The EPSs with and without the RP scheme were developed and the results were compared. During the one month period of July, 2013, a significant difference was shown in the spread of 1.5 m temperature and the Root Mean Square Error and spread of 10 m zonal wind due to application of the RP scheme. For precipitation forecast, the precipitation tended to be overestimated relative to the observation when the RP scheme was applied. Moreover, the forecast became more accurate for heavy precipitations and the longer forecast lead times. For two heavy rainfall cases occurred during the research period, the higher Equitable Threat Score was observed for heavy precipitations in the system with the RP scheme compared to the one without, demonstrating consistency with the statistical results for the research period. Therefore, the predictability for heavy precipitation phenomena that affected the Korean Peninsula increases if the RP scheme is used to consider sub-grid scale uncertainties

  9. Simple lattice Boltzmann subgrid-scale model for convectional flows with high Rayleigh numbers within an enclosed circular annular cavity (United States)

    Chen, Sheng; Tölke, Jonas; Krafczyk, Manfred


    Natural convection within an enclosed circular annular cavity formed by two concentric vertical cylinders is of fundamental interest and practical importance. Generally, the assumption of axisymmetric thermal flow is adopted for simulating such natural convections and the validity of the assumption of axisymmetric thermal flow is still held even for some turbulent convection. Usually the Rayleigh numbers (Ra) of realistic flows are very high. However, the work to design suitable and efficient lattice Boltzmann (LB) models on such flows is quite rare. To bridge the gap, in this paper a simple LB subgrid-scale (SGS) model, which is based on our recent work [S. Chen, J. Tölke, and M. Krafczyk, Phys. Rev. E 79, 016704 (2009); S. Chen, J. Tölke, S. Geller, and M. Krafczyk, Phys. Rev. E 78, 046703 (2008)], is proposed for simulating convectional flow with high Ra within an enclosed circular annular cavity. The key parameter for the SGS model can be quite easily and efficiently evaluated by the present model. The numerical experiments demonstrate that the present model works well for a large range of Ra and Prandtl number (Pr). Though in the present study a popularly used static Smagorinsky turbulence model is adopted to demonstrate how to develop a LB SGS model for simulating axisymmetric thermal flows with high Ra, other state-of-the-art turbulence models can be incorporated into the present model in the same way. In addition, the present model can be extended straightforwardly to simulate other axisymmetric convectional flows with high Ra, for example, turbulent convection with internal volumetric heat generation in a vertical cylinder, which is an important simplified representation of a nuclear reactor.

  10. Sub-grid scale representation of vegetation in global land surface schemes: implications for estimation of the terrestrial carbon sink

    Directory of Open Access Journals (Sweden)

    J. R. Melton


    Full Text Available Terrestrial ecosystem models commonly represent vegetation in terms of plant functional types (PFTs and use their vegetation attributes in calculations of the energy and water balance as well as to investigate the terrestrial carbon cycle. Sub-grid scale variability of PFTs in these models is represented using different approaches with the "composite" and "mosaic" approaches being the two end-members. The impact of these two approaches on the global carbon balance has been investigated with the Canadian Terrestrial Ecosystem Model (CTEM v 1.2 coupled to the Canadian Land Surface Scheme (CLASS v 3.6. In the composite (single-tile approach, the vegetation attributes of different PFTs present in a grid cell are aggregated and used in calculations to determine the resulting physical environmental conditions (soil moisture, soil temperature, etc. that are common to all PFTs. In the mosaic (multi-tile approach, energy and water balance calculations are performed separately for each PFT tile and each tile's physical land surface environmental conditions evolve independently. Pre-industrial equilibrium CLASS-CTEM simulations yield global totals of vegetation biomass, net primary productivity, and soil carbon that compare reasonably well with observation-based estimates and differ by less than 5% between the mosaic and composite configurations. However, on a regional scale the two approaches can differ by > 30%, especially in areas with high heterogeneity in land cover. Simulations over the historical period (1959–2005 show different responses to evolving climate and carbon dioxide concentrations from the two approaches. The cumulative global terrestrial carbon sink estimated over the 1959–2005 period (excluding land use change (LUC effects differs by around 5% between the two approaches (96.3 and 101.3 Pg, for the mosaic and composite approaches, respectively and compares well with the observation-based estimate of 82.2 ± 35 Pg C over the same

  11. Triadic closure dynamics drives scaling laws in social multiplex networks (United States)

    Klimek, Peter; Thurner, Stefan


    Social networks exhibit scaling laws for several structural characteristics, such as degree distribution, scaling of the attachment kernel and clustering coefficients as a function of node degree. A detailed understanding if and how these scaling laws are inter-related is missing so far, let alone whether they can be understood through a common, dynamical principle. We propose a simple model for stationary network formation and show that the three mentioned scaling relations follow as natural consequences of triadic closure. The validity of the model is tested on multiplex data from a well-studied massive multiplayer online game. We find that the three scaling exponents observed in the multiplex data for the friendship, communication and trading networks can simultaneously be explained by the model. These results suggest that triadic closure could be identified as one of the fundamental dynamical principles in social multiplex network formation.

  12. Assessment of subgrid-scale models with a large-eddy simulation-dedicated experimental database: The pulsatile impinging jet in turbulent cross-flow (United States)

    Baya Toda, Hubert; Cabrit, Olivier; Truffin, Karine; Bruneaux, Gilles; Nicoud, Franck


    Large-Eddy Simulation (LES) in complex geometries and industrial applications like piston engines, gas turbines, or aircraft engines requires the use of advanced subgrid-scale (SGS) models able to take into account the main flow features and the turbulence anisotropy. Keeping this goal in mind, this paper reports a LES-dedicated experiment of a pulsatile hot-jet impinging a flat-plate in the presence of a cold turbulent cross-flow. Unlike commonly used academic test cases, this configuration involves different flow features encountered in complex configurations: shear/rotating regions, stagnation point, wall-turbulence, and the propagation of a vortex ring along the wall. This experiment was also designed with the aim to use quantitative and nonintrusive optical diagnostics such as Particle Image Velocimetry, and to easily perform a LES involving a relatively simple geometry and well-controlled boundary conditions. Hence, two eddy-viscosity-based SGS models are investigated: the dynamic Smagorinsky model [M. Germano, U. Piomelli, P. Moin, and W. Cabot, "A dynamic subgrid-scale eddy viscosity model," Phys. Fluids A 3(7), 1760-1765 (1991)] and the σ-model [F. Nicoud, H. B. Toda, O. Cabrit, S. Bose, and J. Lee, "Using singular values to build a subgrid-scale model for large eddy simulations," Phys. Fluids 23(8), 085106 (2011)]. Both models give similar results during the first phase of the experiment. However, it was found that the dynamic Smagorinsky model could not accurately predict the vortex-ring propagation, while the σ-model provides a better agreement with the experimental measurements. Setting aside the implementation of the dynamic procedure (implemented here in its simplest form, i.e., without averaging over homogeneous directions and with clipping of negative values to ensure numerical stability), it is suggested that the mitigated predictions of the dynamic Smagorinsky model are due to the dynamic constant, which strongly depends on the mesh resolution

  13. Recursive renormalization group theory based subgrid modeling (United States)

    Zhou, YE


    Advancing the knowledge and understanding of turbulence theory is addressed. Specific problems to be addressed will include studies of subgrid models to understand the effects of unresolved small scale dynamics on the large scale motion which, if successful, might substantially reduce the number of degrees of freedom that need to be computed in turbulence simulation.

  14. Applying an economical scale-aware PDF-based turbulence closure model in NOAA NCEP GCMs. (United States)

    Krueger, S. K.; Belochitski, A.; Moorthi, S.; Bogenschutz, P.; Pincus, R.


    A novel unified representation of sub-grid scale (SGS) turbulence, cloudiness, and shallow convection is being implemented into the NOAA NCEP Global Forecasting System (GFS) general circulation model. The approach, known as Simplified High Order Closure (SHOC), is based on predicting a joint PDF of SGS thermodynamic variables and vertical velocity and using it to diagnose turbulent diffusion coefficients, SGS fluxes, condensation and cloudiness. Unlike other similar methods, only one new prognostic variable, turbulent kinetic energy (TKE), needs to be intoduced, making the technique computationally efficient.SHOC code was adopted for a global model environment from its origins in a cloud resolving model, and incorporated into NCEP GFS. SHOC was first tested in a non-interactive mode, a configuration where SHOC receives inputs from the host model, but its outputs are not returned to the GFS. In this configuration: a) SGS TKE values produced by GFS SHOC are consistent with those produced by SHOC in a CRM, b) SGS TKE in GFS SHOC exhibits a well defined diurnal cycle, c) there's enhanced boundary layer turbulence in the subtropical stratocumulus and tropical transition-to-cumulus areas d) buoyancy flux diagnosed from the assumed PDF is consistent with independently calculated Brunt-Vaisala frequency in identifying stable and unstable regions.Next, SHOC was coupled to GFS, namely turbulent diffusion coefficients computed by SHOC are now used in place of those currently produced by the GFS boundary layer and shallow convection schemes (Han and Pan, 2011), as well as condensation and cloud fraction diagnosed from the SGS PDF replace those calculated in the current large-scale cloudines scheme (Zhao and Carr, 1997). Ongoing activities consist of debugging the fully coupled GFS/SHOC.Future work will consist of evaluating model performance and tuning the physics if necessary, by performing medium-range NWP forecasts with prescribed initial conditions, and AMIP-type climate

  15. Large Eddy Simulations of a Premixed Jet Combustor Using Flamelet-Generated Manifolds: Effects of Heat Loss and Subgrid-Scale Models

    KAUST Repository

    Hernandez Perez, Francisco E.


    Large eddy simulations of a turbulent premixed jet flame in a confined chamber were conducted using the flamelet-generated manifold technique for chemistry tabulation. The configuration is characterized by an off-center nozzle having an inner diameter of 10 mm, supplying a lean methane-air mixture with an equivalence ratio of 0.71 and a mean velocity of 90 m/s, at 573 K and atmospheric pressure. Conductive heat loss is accounted for in the manifold via burner-stabilized flamelets and the subgrid-scale (SGS) turbulencechemistry interaction is modeled via presumed probability density functions. Comparisons between numerical results and measured data show that a considerable improvement in the prediction of temperature is achieved when heat losses are included in the manifold, as compared to the adiabatic one. Additional improvement in the temperature predictions is obtained by incorporating radiative heat losses. Moreover, further enhancements in the LES predictions are achieved by employing SGS models based on transport equations, such as the SGS turbulence kinetic energy equation with dynamic coefficients. While the numerical results display good agreement up to a distance of 4 nozzle diameters downstream of the nozzle exit, the results become less satisfactory along the downstream, suggesting that further improvements in the modeling are required, among which a more accurate model for the SGS variance of progress variable can be relevant.

  16. Field-scale water balance closure in seasonally frozen conditions

    Directory of Open Access Journals (Sweden)

    X. Pan


    Full Text Available Hydrological water balance closure is a simple concept, yet in practice it is uncommon to measure every significant term independently in the field. Here we demonstrate the degree to which the field-scale water balance can be closed using only routine field observations in a seasonally frozen prairie pasture field site in Saskatchewan, Canada. Arrays of snow and soil moisture measurements were combined with a precipitation gauge and flux tower evapotranspiration estimates. We consider three hydrologically distinct periods: the snow accumulation period over the winter, the snowmelt period in spring, and the summer growing season. In each period, we attempt to quantify the residual between net precipitation (precipitation minus evaporation and the change in field-scale storage (snow and soil moisture, while accounting for measurement uncertainties. When the residual is negligible, a simple 1-D water balance with no net drainage is adequate. When the residual is non-negligible, we must find additional processes to explain the result. We identify the hydrological fluxes which confound the 1-D water balance assumptions during different periods of the year, notably blowing snow and frozen soil moisture redistribution during the snow accumulation period, and snowmelt runoff and soil drainage during the melt period. Challenges associated with quantifying these processes, as well as uncertainties in the measurable quantities, caution against the common use of water balance residuals to estimate fluxes and constrain models in such a complex environment.

  17. Field-scale water balance closure in seasonally frozen conditions (United States)

    Pan, Xicai; Helgason, Warren; Ireson, Andrew; Wheater, Howard


    Hydrological water balance closure is a simple concept, yet in practice it is uncommon to measure every significant term independently in the field. Here we demonstrate the degree to which the field-scale water balance can be closed using only routine field observations in a seasonally frozen prairie pasture field site in Saskatchewan, Canada. Arrays of snow and soil moisture measurements were combined with a precipitation gauge and flux tower evapotranspiration estimates. We consider three hydrologically distinct periods: the snow accumulation period over the winter, the snowmelt period in spring, and the summer growing season. In each period, we attempt to quantify the residual between net precipitation (precipitation minus evaporation) and the change in field-scale storage (snow and soil moisture), while accounting for measurement uncertainties. When the residual is negligible, a simple 1-D water balance with no net drainage is adequate. When the residual is non-negligible, we must find additional processes to explain the result. We identify the hydrological fluxes which confound the 1-D water balance assumptions during different periods of the year, notably blowing snow and frozen soil moisture redistribution during the snow accumulation period, and snowmelt runoff and soil drainage during the melt period. Challenges associated with quantifying these processes, as well as uncertainties in the measurable quantities, caution against the common use of water balance residuals to estimate fluxes and constrain models in such a complex environment.

  18. Intercomparison of different subgrid-scale models for the Large Eddy Simulation of the diurnal evolution of the atmospheric boundary layer during the Wangara experiment (United States)

    Dall'Ozzo, C.; Carissimo, B.; Musson-Genon, L.; Dupont, E.; Milliez, M.


    The study of a whole diurnal cycle of the atmospheric boundary layer evolving through unstable, neutral and stable states is essential to test a model applicable to the dispersion of pollutants. Consequently a LES of a diurnal cycle is performed and compared to observations from the Wangara experiment (Day 33-34). All simulations are done with Code_Saturne [1] an open source CFD code. The synthetic eddy method (SEM) [2] is implemented to initialize turbulence at the beginning of the simulation. Two different subgrid-scale (SGS) models are tested: the Smagorinsky model [3],[4] and the dynamical Wong and Lilly model [5]. The first one, the most classical, uses a Smagorinsky constant Cs to parameterize the dynamical turbulent viscosity while the second one relies on a variable C. Cs remains insensitive to the atmospheric stability level in contrary to the parameter C determined by the Wong and Lilly model. It is based on the error minimization of the difference between the tensors of the resolved turbulent stress (Lij) and the difference of the SGS stress tensors at two different filter scales (Mij). Furthermore, the thermal eddy diffusivity, as opposed to the Smagorinsky model, is calculated with a dynamical Prandtl number determination. The results are confronted to previous simulations from Basu et al. (2008) [6], using a locally averaged scale-dependent dynamic (LASDD) SGS model, and to previous RANS simulations. The accuracy in reproducing the experimental atmospheric conditions is discussed, especially regarding the night time low-level jet formation. In addition, the benefit of the utilization of a coupled radiative model is discussed.

  19. Advanced subgrid-scale modeling for convection-dominated species transport at fluid interfaces with application to mass transfer from rising bubbles (United States)

    Weiner, Andre; Bothe, Dieter


    This paper presents a novel subgrid scale (SGS) model for simulating convection-dominated species transport at deformable fluid interfaces. One possible application is the Direct Numerical Simulation (DNS) of mass transfer from rising bubbles. The transport of a dissolving gas along the bubble-liquid interface is determined by two transport phenomena: convection in streamwise direction and diffusion in interface normal direction. The convective transport for technical bubble sizes is several orders of magnitude higher, leading to a thin concentration boundary layer around the bubble. A true DNS, fully resolving hydrodynamic and mass transfer length scales results in infeasible computational costs. Our approach is therefore a DNS of the flow field combined with a SGS model to compute the mass transfer between bubble and liquid. An appropriate model-function is used to compute the numerical fluxes on all cell faces of an interface cell. This allows to predict the mass transfer correctly even if the concentration boundary layer is fully contained in a single cell layer around the interface. We show that the SGS-model reduces the resolution requirements at the interface by a factor of ten and more. The integral flux correction is also applicable to other thin boundary layer problems. Two flow regimes are investigated to validate the model. A semi-analytical solution for creeping flow is used to assess local and global mass transfer quantities. For higher Reynolds numbers ranging from Re = 100 to Re = 460 and Péclet numbers between Pe =104 and Pe = 4 ṡ106 we compare the global Sherwood number against correlations from literature. In terms of accuracy, the predicted mass transfer never deviates more than 4% from the reference values.

  20. Impact of an additional radiative CO2 cooling induced by subgrid-scale gravity waves in the middle and upper atmosphere (United States)

    Medvedev, A. S.; Yigit, E.; Kutepov, A.; Feofilov, A.


    Atmospheric fluctuations produced by GWs are a substantial source of momentum and energy in the thermosphere (Yigit et al., 2009). These fluctuations also affect radiative transfer and, ultimately, the radiative heating/cooling rates. Recently, Kutepov et al. (2007) developed a methodology to account for radiative effects of subgrid-scale GWs not captured by general circulation models (GCMs). It has been extended by Kutepov et al (2011) to account not only for wave-induced variations of temperature, but also of CO2 and atomic oxygen. It was shown that these GWs can cause additional cooling of up to 3 K/day around mesopause. A key parameter for calculating the additional cooling is the temperature variance associated with GWs, which is a subproduct of conventional GW schemes. In this study, the parameterization of Kutepov et al. (2011) has been implemented into a 3-D comprehensive GCM that incorporates the effects of unresolved GWs via the extended nonlinear scheme of Yigit et al. (2008). Simulated net effects of the additional radiative CO2 cooling on the temperature and wind in the mesosphere and lower thermosphere are presented and discussed for solstice conditions. 1. Kutepov, A. A, A. G. Feofilov, A. S. Medvedev, A. W. A. Pauldrach, and P. Hartogh (2007), Geophys. Res. Lett. 34, L24807, doi:10.1029/2007GL032392. 2. Kutepov, A. A., A. G. Feofilov, A. S. Medvedev, U. Berger, and M. Kaufmann (2011), submitted to Geophys. Res. Letts. 3. Yigit, E., A. D. Aylward, and A. S. Medvedev (2008), J. Geophys. Res., 113, D19106, doi:10.1029/2008JD010135. 4. Yigit, E., A. S. Medvedev, A. D. Aylward, P. Hartogh, and M. J. Harris (2009), J. Geophys. Res., 114, D07101, doi:10.1029/2008JD011132.

  1. Modeling lightning-NOx chemistry on a sub-grid scale in a global chemical transport model

    Directory of Open Access Journals (Sweden)

    A. Gressent


    Full Text Available For the first time, a plume-in-grid approach is implemented in a chemical transport model (CTM to parameterize the effects of the nonlinear reactions occurring within high concentrated NOx plumes from lightning NOx emissions (LNOx in the upper troposphere. It is characterized by a set of parameters including the plume lifetime, the effective reaction rate constant related to NOx–O3 chemical interactions, and the fractions of NOx conversion into HNO3 within the plume. Parameter estimates were made using the Dynamical Simple Model of Atmospheric Chemical Complexity (DSMACC box model, simple plume dispersion simulations, and the 3-D Meso-NH (non-hydrostatic mesoscale atmospheric model. In order to assess the impact of the LNOx plume approach on the NOx and O3 distributions on a large scale, simulations for the year 2006 were performed using the GEOS-Chem global model with a horizontal resolution of 2° × 2.5°. The implementation of the LNOx parameterization implies an NOx and O3 decrease on a large scale over the region characterized by a strong lightning activity (up to 25 and 8 %, respectively, over central Africa in July and a relative increase downwind of LNOx emissions (up to 18 and 2 % for NOx and O3, respectively, in July. The calculated variability in NOx and O3 mixing ratios around the mean value according to the known uncertainties in the parameter estimates is at a maximum over continental tropical regions with ΔNOx [−33.1, +29.7] ppt and ΔO3 [−1.56, +2.16] ppb, in January, and ΔNOx [−14.3, +21] ppt and ΔO3 [−1.18, +1.93] ppb, in July, mainly depending on the determination of the diffusion properties of the atmosphere and the initial NO mixing ratio injected by lightning. This approach allows us (i to reproduce a more realistic lightning NOx chemistry leading to better NOx and O3 distributions on the large scale and (ii to focus on other improvements to reduce remaining uncertainties from processes

  2. Effect of reactions in small eddies on biomass gasification with eddy dissipation concept - Sub-grid scale reaction model. (United States)

    Chen, Juhui; Yin, Weijie; Wang, Shuai; Meng, Cheng; Li, Jiuru; Qin, Bai; Yu, Guangbin


    Large-eddy simulation (LES) approach is used for gas turbulence, and eddy dissipation concept (EDC)-sub-grid scale (SGS) reaction model is employed for reactions in small eddies. The simulated gas molar fractions are in better agreement with experimental data with EDC-SGS reaction model. The effect of reactions in small eddies on biomass gasification is emphatically analyzed with EDC-SGS reaction model. The distributions of the SGS reaction rates which represent the reactions in small eddies with particles concentration and temperature are analyzed. The distributions of SGS reaction rates have the similar trend with those of total reactions rates and the values account for about 15% of the total reactions rates. The heterogeneous reaction rates with EDC-SGS reaction model are also improved during the biomass gasification process in bubbling fluidized bed. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. Numerical simulation of the dynamic flow behavior in a bubble column: a study of closures for turbulence and interface forces

    NARCIS (Netherlands)

    Zhang, D.; Deen, N.G.; Kuipers, J.A.M.


    Numerical simulations of the bubbly flow in two square cross-sectioned bubble columns were conducted with the commercial CFD package CFX-4.4. The effect of the model constant used in the sub-grid scale (SGS) model, CS, as well as the interfacial closures for the drag, lift and virtual mass forces

  4. Predicting the impacts of fishing canals on Floodplain Dynamics in Northern Cameroon using a small-scale sub-grid hydraulic model (United States)

    Shastry, A. R.; Durand, M. T.; Fernandez, A.; Hamilton, I.; Kari, S.; Labara, B.; Laborde, S.; Mark, B. G.; Moritz, M.; Neal, J. C.; Phang, S. C.


    Modeling Regime Shifts in the Logone floodplain (MORSL) is an ongoing interdisciplinary project at The Ohio State University studying the ecological, social and hydrological system of the region. This floodplain, located in Northern Cameroon, is part of the Lake Chad basin. Between September and October the floodplain is inundated by the overbank flow from the Logone River, which is important for agriculture and fishing. Fishermen build canals to catch fish during the flood's recession to the river by installing fishnets at the intersection of the canals and the river. Fishing canals thus connect the river to natural depressions of the terrain, which act as seasonal ponds during this part of the year. Annual increase in the number of canals affect hydraulics and hence fishing in the region. In this study, the Bara region (1 km2) of the Logone floodplain, through which Lorome Mazra flows, is modeled using LISFLOOD-FP, a raster-based model with sub-grid parameterizations of canals. The aim of the study is to find out how the small-scale, local features like canals and fishnets govern the flow, so that it can be incorporated in a large-scale model of the floodplain at a coarser spatial resolution. We will also study the effect of increasing number of canals on the flooding pattern. We use a simplified version of the hydraulic system at a grid-cell size of 30-m, using synthetic topography, parameterized fishing canals, and representing fishnets as trash screens. The inflow at Bara is obtained from a separate, lower resolution (1-km grid-cell) model run, which is forced by daily discharge records obtained from Katoa, located about 25-km to the south of Bara. The model appropriately captures the rise and recession of the annual flood, supporting use of the LISFLOOD-FP approach. Predicted water levels at specific points in the river, the canals, the depression and the floodplain will be compared to field measured heights of flood recession in Bara, November 2014.

  5. Scaling laws and turbulence closures for stable boundary layers (United States)

    Zilitinkevich, S.; Esau, I.; Baklanov, A.; Djolov, G.


    This paper presents a recently developed theory of non-local turbulence in the stably stratified planetary boundary layers (PBLs): basic theoretical results, new LES code specifically designed for LES of stably stratified flows, and comparison of theoretical predictions with LES and experimental data. The paper includes improved formulations for the PBL depth and resistance laws and outlines an advanced turbulence closure accounting for the transport properties of internal gravity waves.

  6. Birefringent dispersive FDTD subgridding scheme


    De Deckere, B; Van Londersele, Arne; De Zutter, Daniël; Vande Ginste, Dries


    A novel 2D finite difference time domain (FDTD) subgridding method is proposed, only subject to the Courant limit of the coarse grid. By making mu or epsilon inside the subgrid dispersive, unconditional stability is induced at the cost of a sparse, implicit set of update equations. By only adding dispersion along preferential directions, it is possible to dramatically reduce the rank of the matrix equation that needs to be solved.

  7. Glottal closure instant and voice source analysis using time-scale ...

    Indian Academy of Sciences (India)

    For each period, the optimal LoMA is computed by linking amplitude maxima at each scale of a wavelet transform, using a dynamic programming algorithm. A time-scale analysis of the linear acoustic model of speech production shows several interesting properties. The LoMA points to the glottal closure instants. The LoMA ...

  8. Examination of convective parameterization closures and their scale awareness using cloud-resolving model simulations (United States)

    Ettammal, S.; Zhang, G. J.; Chen, R.


    Closure is the main component of a mass flux-based convective parameterization scheme and it determines the amount of convection under a given large-scale condition. In this study, we use cloud-resolving model output from simulations of both tropical and midlatitude convection to evaluate commonly used closures for a range of global climate model (GCM) horizontal resolutions, taking convective precipitation and mass flux at 600 hPa as measures for deep convection. To mimic different GCM horizontal resolutions, we use high resolution CRM data to create domain averages representing GCM horizontal resolutions of 128 km, 64 km, 32 km, 16 km, 8 km and 4 km. Lead-lag correlation analysis shows that except moisture convergence and turbulent kinetic energy (TKE), none of the other closure variables evaluated in this study show any relationship with convection for the six subdomain sizes. It is found that the correlation between moisture convergence and convective precipitation is largest when moisture convergence leads convection. This correlation weakens as the subdomain size decreases to 8 km or smaller. Although convective precipitation and mass flux increase with moisture convergence, as the subdomain size increases the rate at which they increase becomes smaller. This suggests that moisture convergence-based closure should scale down the predicted mass flux for given moisture convergence as GCM resolution increases. Lead-lag correlation and composite analysis show that TKE is largely a result of convection and therefore its use in a closure variable is not supported.

  9. A subgrid parameterization scheme for precipitation

    Directory of Open Access Journals (Sweden)

    S. Turner


    Full Text Available With increasing computing power, the horizontal resolution of numerical weather prediction (NWP models is improving and today reaches 1 to 5 km. Nevertheless, clouds and precipitation formation are still subgrid scale processes for most cloud types, such as cumulus and stratocumulus. Subgrid scale parameterizations for water vapor condensation have been in use for many years and are based on a prescribed probability density function (PDF of relative humidity spatial variability within the model grid box, thus providing a diagnosis of the cloud fraction. A similar scheme is developed and tested here. It is based on a prescribed PDF of cloud water variability and a threshold value of liquid water content for droplet collection to derive a rain fraction within the model grid. Precipitation of rainwater raises additional concerns relative to the overlap of cloud and rain fractions, however. The scheme is developed following an analysis of data collected during field campaigns in stratocumulus (DYCOMS-II and fair weather cumulus (RICO and tested in a 1-D framework against large eddy simulations of these observed cases. The new parameterization is then implemented in a 3-D NWP model with a horizontal resolution of 2.5 km to simulate real cases of precipitating cloud systems over France.

  10. Performance of four turbulence closure models implemented using a generic length scale method (United States)

    Warner, J.C.; Sherwood, C.R.; Arango, H.G.; Signell, R.P.


    A two-equation turbulence model (one equation for turbulence kinetic energy and a second for a generic turbulence length-scale quantity) proposed by Umlauf and Burchard [J. Marine Research 61 (2003) 235] is implemented in a three-dimensional oceanographic model (Regional Oceanographic Modeling System; ROMS v2.0). These two equations, along with several stability functions, can represent many popular turbulence closures, including the k-kl (Mellor-Yamada Level 2.5), k-??, and k-?? schemes. The implementation adds flexibility to the model by providing an unprecedented range of turbulence closure selections in a single 3D oceanographic model and allows comparison and evaluation of turbulence models in an otherwise identical numerical environment. This also allows evaluation of the effect of turbulence models on other processes such as suspended-sediment distribution or ecological processes. Performance of the turbulence models and sediment-transport schemes is investigated with three test cases for (1) steady barotropic flow in a rectangular channel, (2) wind-induced surface mixed-layer deepening in a stratified fluid, and (3) oscillatory stratified pressure-gradient driven flow (estuarine circulation) in a rectangular channel. Results from k-??, k-??, and gen (a new closure proposed by Umlauf and Burchard [J. Marine Research 61 (2003) 235]) are very similar for these cases, but the k-kl closure results depend on a wall-proximity function that must be chosen to suit the flow. Greater variations appear in simulations of suspended-sediment concentrations than in salinity simulations because the transport of suspended-sediment amplifies minor variations in the methods. The amplification is caused by the added physics of a vertical settling rate, bottom stress dependent resuspension, and diffusive transport of sediment in regions of well mixed salt and temperature. Despite the amplified sensitivity of sediment to turbulence models in the estuary test case, the four

  11. Simulation of Boundary-Layer Cumulus and Stratocumulus Clouds using a Cloud-Resolving Model With Low- and Third-Order Turbulence Closures (United States)

    Xu, Kuan-Man; Cheng, Anning


    The effects of subgrid-scale condensation and transport become more important as the grid spacings increase from those typically used in large-eddy simulation (LES) to those typically used in cloud-resolving models (CRMs). Incorporation of these effects can be achieved by a joint probability density function approach that utilizes higher-order moments of thermodynamic and dynamic variables. This study examines how well shallow cumulus and stratocumulus clouds are simulated by two versions of a CRM that is implemented with low-order and third-order turbulence closures (LOC and TOC) when a typical CRM horizontal resolution is used and what roles the subgrid-scale and resolved-scale processes play as the horizontal grid spacing of the CRM becomes finer. Cumulus clouds were mostly produced through subgrid-scale transport processes while stratocumulus clouds were produced through both subgrid-scale and resolved-scale processes in the TOC version of the CRM when a typical CRM grid spacing is used. The LOC version of the CRM relied upon resolved-scale circulations to produce both cumulus and stratocumulus clouds, due to small subgrid-scale transports. The mean profiles of thermodynamic variables, cloud fraction and liquid water content exhibit significant differences between the two versions of the CRM, with the TOC results agreeing better with the LES than the LOC results. The characteristics, temporal evolution and mean profiles of shallow cumulus and stratocumulus clouds are weakly dependent upon the horizontal grid spacing used in the TOC CRM. However, the ratio of the subgrid-scale to resolved-scale fluxes becomes smaller as the horizontal grid spacing decreases. The subcloud-layer fluxes are mostly due to the resolved scales when a grid spacing less than or equal to 1 km is used. The overall results of the TOC simulations suggest that a 1-km grid spacing is a good choice for CRM simulation of shallow cumulus and stratocumulus.

  12. A data-driven analysis of energy balance closure across FLUXNET research sites: The role of landscape scale heterogeneity

    DEFF Research Database (Denmark)

    Stoy, Paul C.; Mauder, Matthias; Foken, Thomas


    . We analyzed energy balance closure across 173 ecosystems in the FLUXNET database and explored the relationship between energy balance closure and landscape heterogeneity using MODIS products and GLOBEstat elevation data. Energy balance closure per research site (CEB,s) averaged 0.84±0.20, with best......The energy balance at most surface-atmosphere flux research sites remains unclosed. The mechanisms underlying the discrepancy between measured energy inputs and outputs across the global FLUXNET tower network are still under debate. Recent reviews have identified exchange processes and turbulent...... motions at large spatial and temporal scales in heterogeneous landscapes as the primary cause of the lack of energy balance closure at some intensively-researched sites, while unmeasured storage terms cannot be ruled out as a dominant contributor to the lack of energy balance closure at many other sites...

  13. Anomalous Scaling from Controlled Closure in a Shell Model of Turbulence

    CERN Document Server

    Lvov, V S; Pomyalov, A; Procaccia, I; L'vov, Victor S.; Pierotti, Daniela; Pomyalov, Anna; Procaccia, Itamar


    We present a model of hydrodynamic turbulence for which the program of computing the scaling exponents from first principles can be developed in a controlled fashion. The model consists of $N$ suitably coupled copies of the "Sabra" shell model of turbulence. The couplings are chosen to include two components: random and deterministic, with a relative importance that is characterized by a parameter called $\\epsilon$. It is demonstrated, using numerical simulations of up to 25 copies and 28 shells that in the $N\\to functions whose scaling exponents are anomalous. The theoretical calculation of the scaling exponents follows verbatim the closure procedure suggested recently for the Navier-Stokes problem, with the additional advantage that in the $N\\to procedure. The main result of this paper is a finite and closed set of scale-invariant equations for the 2nd and 3rd order statistical objects of the theory. This set of equations takes into account terms up to order $\\epsilon^4$ and neglects terms of order $\\epsilo...

  14. The Sensitivity of Simulated Competition Between Different Plant Functional Types to Subgrid Scale Representation of Vegetation in a Land Surface Model (United States)

    Shrestha, R. K.; Arora, V.; Melton, J. R.


    Vegetation is a dynamic component of the earth system that affects weather and climate at hourly to centennial time scales. However, most current dynamic vegetation models do not explicitly simulate competition among Plant Functional Types (PFTs). Here we use the coupled CLASS-CTEM model (Canadian Land Surface Scheme coupled to Canadian Terrestrial Ecosystem Model) to explicitly simulate competition between nine PFTs for available space using a modified version of Lotka - Volterra (LV) predator-prey equations. The nine PFTs include evergreen and deciduous needleleaf trees, evergreen and cold and drought deciduous broadleaf trees and C3 and C4 crops and grasses. The CLASS-CTEM model can be configured either in the composite (single tile) or the mosaic (multiple tiles) mode. Our results show that the model is sensitive to the chosen mode. The simulated fractional coverage of PFTs are similar between two approaches at some locations whereas at the other locations the two approaches yield different results. The simulated fractional coverage of PFTs are also compared with the available observations-based estimates. Simulated results at selected locations across the globe show that the model is able to realistically simulate the fractional coverage of tree and grass PFTs and the bare fraction, as well as the fractional coverage of individual tree and grass PFTs. Along with the observed patterns of vegetation distribution the CLASS-CTEM modelling framework is also able to simulate realistic succession patterns. Some differences remain and these are attributed to the coarse spatial resolution of the model (~3.75°) and the limited number of PFTs represented in the model.

  15. Subgrid Parameterization of the Soil Moisture Storage Capacity for a Distributed Rainfall-Runoff Model

    Directory of Open Access Journals (Sweden)

    Weijian Guo


    Full Text Available Spatial variability plays an important role in nonlinear hydrologic processes. Due to the limitation of computational efficiency and data resolution, subgrid variability is usually assumed to be uniform for most grid-based rainfall-runoff models, which leads to the scale-dependence of model performances. In this paper, the scale effect on the Grid-Xinanjiang model was examined. The bias of the estimation of precipitation, runoff, evapotranspiration and soil moisture at the different grid scales, along with the scale-dependence of the effective parameters, highlights the importance of well representing the subgrid variability. This paper presents a subgrid parameterization method to incorporate the subgrid variability of the soil storage capacity, which is a key variable that controls runoff generation and partitioning in the Grid-Xinanjiang model. In light of the similar spatial pattern and physical basis, the soil storage capacity is correlated with the topographic index, whose spatial distribution can more readily be measured. A beta distribution is introduced to represent the spatial distribution of the soil storage capacity within the grid. The results derived from the Yanduhe Basin show that the proposed subgrid parameterization method can effectively correct the watershed soil storage capacity curve. Compared to the original Grid-Xinanjiang model, the model performances are quite consistent at the different grid scales when the subgrid variability is incorporated. This subgrid parameterization method reduces the recalibration necessity when the Digital Elevation Model (DEM resolution is changed. Moreover, it improves the potential for the application of the distributed model in the ungauged basin.

  16. Triadic closure dynamics explains scaling-exponents for preferential attachment-, degree- and clustering distributions in social multiplex data

    CERN Document Server

    Klimek, Peter


    Social networks exhibit scaling-laws for several structural characteristics, such as the degree distribution, the scaling of the attachment kernel, and the clustering coefficients as a function of node degree. A detailed understanding if and how these scaling laws are inter-related is missing so far, let alone whether they can be understood through a common, dynamical principle. We propose a simple model for stationary network formation and show that the three mentioned scaling relations follow as natural consequences of triadic closure. The validity of the model is tested on multiplex data from a well studied massive multiplayer online game. We find that the three scaling exponents observed in the multiplex data for the friendship, communication and trading networks can simultaneously be explained by the model. These results suggest that triadic closure could be identified as one of the fundamental dynamical principles in social multiplex network formation.

  17. Quantitative modelling of the closure of meso-scale parallel currents in the nightside ionosphere

    Directory of Open Access Journals (Sweden)

    A. Marchaudon


    Full Text Available On 12 January 2000, during a northward IMF period, two successive conjunctions occur between the CUTLASS SuperDARN radar pair and the two satellites Ørsted and FAST. This situation is used to describe and model the electrodynamic of a nightside meso-scale arc associated with a convection shear. Three field-aligned current sheets, one upward and two downward on both sides, are observed.

    Based on the measurements of the parallel currents and either the conductance or the electric field profile, a model of the ionospheric current closure is developed along each satellite orbit. This model is one-dimensional, in a first attempt and a two-dimensional model is tested for the Ørsted case. These models allow one to quantify the balance between electric field gradients and ionospheric conductance gradients in the closure of the field-aligned currents.

    These radar and satellite data are also combined with images from Polar-UVI, allowing for a description of the time evolution of the arc between the two satellite passes. The arc is very dynamic, in spite of quiet solar wind conditions. Periodic enhancements of the convection and of electron precipitation associated with the arc are observed, probably associated with quasi-periodic injections of particles due to reconnection in the magnetotail. Also, a northward shift and a reorganisation of the precipitation pattern are observed, together with a southward shift of the convection shear.

    Key words. Ionosphere (auroral ionosphere; electric fields and currents; particle precipitation – Magnetospheric physics (magnetosphere-ionosphere interactions

  18. Quantitative modelling of the closure of meso-scale parallel currents in the nightside ionosphere

    Directory of Open Access Journals (Sweden)

    A. Marchaudon


    Full Text Available On 12 January 2000, during a northward IMF period, two successive conjunctions occur between the CUTLASS SuperDARN radar pair and the two satellites Ørsted and FAST. This situation is used to describe and model the electrodynamic of a nightside meso-scale arc associated with a convection shear. Three field-aligned current sheets, one upward and two downward on both sides, are observed. Based on the measurements of the parallel currents and either the conductance or the electric field profile, a model of the ionospheric current closure is developed along each satellite orbit. This model is one-dimensional, in a first attempt and a two-dimensional model is tested for the Ørsted case. These models allow one to quantify the balance between electric field gradients and ionospheric conductance gradients in the closure of the field-aligned currents. These radar and satellite data are also combined with images from Polar-UVI, allowing for a description of the time evolution of the arc between the two satellite passes. The arc is very dynamic, in spite of quiet solar wind conditions. Periodic enhancements of the convection and of electron precipitation associated with the arc are observed, probably associated with quasi-periodic injections of particles due to reconnection in the magnetotail. Also, a northward shift and a reorganisation of the precipitation pattern are observed, together with a southward shift of the convection shear. Key words. Ionosphere (auroral ionosphere; electric fields and currents; particle precipitation – Magnetospheric physics (magnetosphere-ionosphere interactions

  19. Subgrid Modeling Geomorphological and Ecological Processes in Salt Marsh Evolution (United States)

    Shi, F.; Kirby, J. T., Jr.; Wu, G.; Abdolali, A.; Deb, M.


    Numerical modeling a long-term evolution of salt marshes is challenging because it requires an extensive use of computational resources. Due to the presence of narrow tidal creeks, variations of salt marsh topography can be significant over spatial length scales on the order of a meter. With growing availability of high-resolution bathymetry measurements, like LiDAR-derived DEM data, it is increasingly desirable to run a high-resolution model in a large domain and for a long period of time to get trends of sedimentation patterns, morphological change and marsh evolution. However, high spatial-resolution poses a big challenge in both computational time and memory storage, when simulating a salt marsh with dimensions of up to O(100 km^2) with a small time step. In this study, we have developed a so-called Pre-storage, Sub-grid Model (PSM, Wu et al., 2015) for simulating flooding and draining processes in salt marshes. The simulation of Brokenbridge salt marsh, Delaware, shows that, with the combination of the sub-grid model and the pre-storage method, over 2 orders of magnitude computational speed-up can be achieved with minimal loss of model accuracy. We recently extended PSM to include a sediment transport component and models for biomass growth and sedimentation in the sub-grid model framework. The sediment transport model is formulated based on a newly derived sub-grid sediment concentration equation following Defina's (2000) area-averaging procedure. Suspended sediment transport is modeled by the advection-diffusion equation in the coarse grid level, but the local erosion and sedimentation rates are integrated over the sub-grid level. The morphological model is based on the existing morphological model in NearCoM (Shi et al., 2013), extended to include organic production from the biomass model. The vegetation biomass is predicted by a simple logistic equation model proposed by Marani et al. (2010). The biomass component is loosely coupled with hydrodynamic and

  20. A scalable moment-closure approximation for large-scale biochemical reaction networks. (United States)

    Kazeroonian, Atefeh; Theis, Fabian J; Hasenauer, Jan


    Stochastic molecular processes are a leading cause of cell-to-cell variability. Their dynamics are often described by continuous-time discrete-state Markov chains and simulated using stochastic simulation algorithms. As these stochastic simulations are computationally demanding, ordinary differential equation models for the dynamics of the statistical moments have been developed. The number of state variables of these approximating models, however, grows at least quadratically with the number of biochemical species. This limits their application to small- and medium-sized processes. In this article, we present a scalable moment-closure approximation (sMA) for the simulation of statistical moments of large-scale stochastic processes. The sMA exploits the structure of the biochemical reaction network to reduce the covariance matrix. We prove that sMA yields approximating models whose number of state variables depends predominantly on local properties, i.e. the average node degree of the reaction network, instead of the overall network size. The resulting complexity reduction is assessed by studying a range of medium- and large-scale biochemical reaction networks. To evaluate the approximation accuracy and the improvement in computational efficiency, we study models for JAK2/STAT5 signalling and NF κ B signalling. Our method is applicable to generic biochemical reaction networks and we provide an implementation, including an SBML interface, which renders the sMA easily accessible. The sMA is implemented in the open-source MATLAB toolbox CERENA and is available from . or Supplementary data are available at Bioinformatics online.

  1. A refined statistical cloud closure using double-Gaussian probability density functions (United States)

    Naumann, A. K.; Seifert, A.; Mellado, J. P.


    We introduce a probability density function (PDF)-based scheme to parameterize cloud fraction, average liquid water and liquid water flux in large-scale models, that is developed from and tested against large-eddy simulations and observational data. Because the tails of the PDFs are crucial for an appropriate parameterization of cloud properties, we use a double-Gaussian distribution that is able to represent the observed, skewed PDFs properly. Introducing two closure equations, the resulting parameterization relies on the first three moments of the subgrid variability of temperature and moisture as input parameters. The parameterization is found to be superior to a single-Gaussian approach in diagnosing the cloud fraction and average liquid water profiles. A priori testing also suggests improved accuracy compared to existing double-Gaussian closures. Furthermore, we find that the error of the new parameterization is smallest for a horizontal resolution of about 5-20 km and also depends on the appearance of mesoscale structures that are accompanied by higher rain rates. In combination with simple autoconversion schemes that only depend on the liquid water, the error introduced by the new parameterization is orders of magnitude smaller than the difference between various autoconversion schemes. For the liquid water flux, we introduce a parameterization that is depending on the skewness of the subgrid variability of temperature and moisture and that reproduces the profiles of the liquid water flux well.

  2. RELAP-7 Closure Correlations

    Energy Technology Data Exchange (ETDEWEB)

    Zou, Ling [Idaho National Lab. (INL), Idaho Falls, ID (United States); Berry, R. A. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Martineau, R. C. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Andrs, D. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Zhang, H. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Hansel, J. E. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Sharpe, J. P. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Johns, Russell C. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)


    The RELAP-7 code is the next generation nuclear reactor system safety analysis code being developed at the Idaho National Laboratory (INL). The code is based on the INL’s modern scientific software development framework, MOOSE (Multi-Physics Object Oriented Simulation Environment). The overall design goal of RELAP-7 is to take advantage of the previous thirty years of advancements in computer architecture, software design, numerical integration methods, and physical models. The end result will be a reactor systems analysis capability that retains and improves upon RELAP5’s and TRACE’s capabilities and extends their analysis capabilities for all reactor system simulation scenarios. The RELAP-7 code utilizes the well-posed 7-equation two-phase flow model for compressible two-phase flow. Closure models used in the TRACE code has been reviewed and selected to reflect the progress made during the past decades and provide a basis for the colure correlations implemented in the RELAP-7 code. This document provides a summary on the closure correlations that are currently implemented in the RELAP-7 code. The closure correlations include sub-grid models that describe interactions between the fluids and the flow channel, and interactions between the two phases.

  3. Test of small-scale central-core-cavity closure for a 300-MW(e) GCFR

    Energy Technology Data Exchange (ETDEWEB)

    Robinson, G.C.; Dougan, J.R.; Naus, D.J.


    Under the Prestressed Concrete Reactor Vessel (PCRV) Program at the Oak Ridge National Laboratory, model tests are conducted to verify the design of the PCRV for a 300 MW(e) Gas-Cooled Fast Reactor (GCFR). Prominent features of the 1:20-scale central core cavity model included a close pitched array of fifty-five penetration tubes, forty-four segmented gusset/bearing plate assemblies, and intermeshed reinforcing steel. The closure model which was designed for a maximum cavity pressure (MCP) of 10.08 MPa was initially tested by applying 10 pressurization cycles from essentially no load to the MCP with strain and deflection data obtained during each cycle. This was followed by pressurization cycles to 32.8 MPa, 41.3 MPa, 48.3 MPa, 58.4 MPa and 79.3 MPa. At a pressure of 79.3 MPa an end cap on a penetration tube developed leaks and the test was terminated. An inelastic analysis was conducted to provide an estimate of the ultimate strength of the closure plug and to determine the potential mode of failure.

  4. Efficient non-hydrostatic modelling of 3D wave-induced currents using a subgrid approach (United States)

    Rijnsdorp, Dirk P.; Smit, Pieter B.; Zijlema, Marcel; Reniers, Ad J. H. M.


    Wave-induced currents are an ubiquitous feature in coastal waters that can spread material over the surf zone and the inner shelf. These currents are typically under resolved in non-hydrostatic wave-flow models due to computational constraints. Specifically, the low vertical resolutions adequate to describe the wave dynamics - and required to feasibly compute at the scales of a field site - are too coarse to account for the relevant details of the three-dimensional (3D) flow field. To describe the relevant dynamics of both wave and currents, while retaining a model framework that can be applied at field scales, we propose a two grid approach to solve the governing equations. With this approach, the vertical accelerations and non-hydrostatic pressures are resolved on a relatively coarse vertical grid (which is sufficient to accurately resolve the wave dynamics), whereas the horizontal velocities and turbulent stresses are resolved on a much finer subgrid (of which the resolution is dictated by the vertical scale of the mean flows). This approach ensures that the discrete pressure Poisson equation - the solution of which dominates the computational effort - is evaluated on the coarse grid scale, thereby greatly improving efficiency, while providing a fine vertical resolution to resolve the vertical variation of the mean flow. This work presents the general methodology, and discusses the numerical implementation in the SWASH wave-flow model. Model predictions are compared with observations of three flume experiments to demonstrate that the subgrid approach captures both the nearshore evolution of the waves, and the wave-induced flows like the undertow profile and longshore current. The accuracy of the subgrid predictions is comparable to fully resolved 3D simulations - but at much reduced computational costs. The findings of this work thereby demonstrate that the subgrid approach has the potential to make 3D non-hydrostatic simulations feasible at the scale of a

  5. Cloud Feedbacks on Greenhouse Warming in a Multi-Scale Modeling Framework with a Higher-Order Turbulence Closure (United States)

    Cheng, Anning; Xu, Kuan-Man


    Five-year simulation experiments with a multi-scale modeling Framework (MMF) with a advanced intermediately prognostic higher-order turbulence closure (IPHOC) in its cloud resolving model (CRM) component, also known as SPCAM-IPHOC (super parameterized Community Atmospheric Model), are performed to understand the fast tropical (30S-30N) cloud response to an instantaneous doubling of CO2 concentration with SST held fixed at present-day values. SPCAM-IPHOC has substantially improved the low-level representation compared with SPCAM. It is expected that the cloud responses to greenhouse warming in SPCAM-IPHOC is more realistic. The change of rising motion, surface precipitation, cloud cover, and shortwave and longwave cloud radiative forcing in SPCAM-IPHOC from the greenhouse warming will be presented in the presentation.

  6. Monte Carlo-based subgrid parameterization of vertical velocity and stratiform cloud microphysics in ECHAM5.5-HAM2

    Directory of Open Access Journals (Sweden)

    J. Tonttila


    Full Text Available A new method for parameterizing the subgrid variations of vertical velocity and cloud droplet number concentration (CDNC is presented for general circulation models (GCMs. These parameterizations build on top of existing parameterizations that create stochastic subgrid cloud columns inside the GCM grid cells, which can be employed by the Monte Carlo independent column approximation approach for radiative transfer. The new model version adds a description for vertical velocity in individual subgrid columns, which can be used to compute cloud activation and the subgrid distribution of the number of cloud droplets explicitly. Autoconversion is also treated explicitly in the subcolumn space. This provides a consistent way of simulating the cloud radiative effects with two-moment cloud microphysical properties defined at subgrid scale. The primary impact of the new parameterizations is to decrease the CDNC over polluted continents, while over the oceans the impact is smaller. Moreover, the lower CDNC induces a stronger autoconversion of cloud water to rain. The strongest reduction in CDNC and cloud water content over the continental areas promotes weaker shortwave cloud radiative effects (SW CREs even after retuning the model. However, compared to the reference simulation, a slightly stronger SW CRE is seen e.g. over mid-latitude oceans, where CDNC remains similar to the reference simulation, and the in-cloud liquid water content is slightly increased after retuning the model.

  7. Glottal closure instant and voice source analysis using time-scale ...

    Indian Academy of Sciences (India)

    of psychological scale, such as third-octave, Bark, Mel or Equivalent Rectangular Bandwidth. (ERB) scales. The filtering ... The top panel displays only positive part of the filter outputs. 'We hear' spoken by female .... This shows that lines of positive amplitudes are converging to the peak position. The lines cor- responding to ...

  8. Unsteady Flame Embedding (UFE) Subgrid Model for Turbulent Premixed Combustion Simulations

    KAUST Repository

    El-Asrag, Hossam


    We present a formulation for an unsteady subgrid model for premixed combustion in the flamelet regime. Since chemistry occurs at the unresolvable scales, it is necessary to introduce a subgrid model that accounts for the multi-scale nature of the problem using the information available on the resolved scales. Most of the current models are based on the laminar flamelet concept, and often neglect the unsteady effects. The proposed model\\'s primary objective is to encompass many of the flame/turbulence interactions unsteady features and history effects. In addition it provides a dynamic and accurate approach for computing the subgrid flame propagation velocity. The unsteady flame embedding approach (UFE) treats the flame as an ensemble of locally one-dimensional flames. A set of elemental one dimensional flames is used to describe the turbulent flame structure at the subgrid level. The stretched flame calculations are performed on the stagnation line of a strained flame using the unsteady filtered strain rate computed from the resolved- grid. The flame iso-surface is tracked using an accurate high-order level set formulation to propagate the flame interface at the coarse resolution with minimum numerical diffusion. In this paper the solver and the model components are introduced and used to investigate two unsteady flames with different Lewis numbers in the thin reaction zone regime. The results show that the UFE model captures the unsteady flame-turbulence interactions and the flame propagation speed reasonably well. Higher propagation speed is observed for the lower than unity Lewis number flame because of the impact of differential diffusion.

  9. Discontinuous Galerkin Subgrid Finite Element Method for Heterogeneous Brinkman’s Equations

    KAUST Repository

    Iliev, Oleg P.


    We present a two-scale finite element method for solving Brinkman\\'s equations with piece-wise constant coefficients. This system of equations model fluid flows in highly porous, heterogeneous media with complex topology of the heterogeneities. We make use of the recently proposed discontinuous Galerkin FEM for Stokes equations by Wang and Ye in [12] and the concept of subgrid approximation developed for Darcy\\'s equations by Arbogast in [4]. In order to reduce the error along the coarse-grid interfaces we have added a alternating Schwarz iteration using patches around the coarse-grid boundaries. We have implemented the subgrid method using Deal.II FEM library, [7], and we present the computational results for a number of model problems. © 2010 Springer-Verlag Berlin Heidelberg.

  10. A new downscaling method for sub-grid turbulence modeling

    Directory of Open Access Journals (Sweden)

    L. Rottner


    Full Text Available In this study we explore a new way to model sub-grid turbulence using particle systems. The ability of particle systems to model small-scale turbulence is evaluated using high-resolution numerical simulations. These high-resolution data are averaged to produce a coarse-grid velocity field, which is then used to drive a complete particle-system-based downscaling. Wind fluctuations and turbulent kinetic energy are compared between the particle simulations and the high-resolution simulation. Despite the simplicity of the physical model used to drive the particles, the results show that the particle system is able to represent the average field. It is shown that this system is able to reproduce much finer turbulent structures than the numerical high-resolution simulations. In addition, this study provides an estimate of the effective spatial and temporal resolution of the numerical models. This highlights the need for higher-resolution simulations in order to evaluate the very fine turbulent structures predicted by the particle systems. Finally, a study of the influence of the forcing scale on the particle system is presented.

  11. Surgical Scales: Primary Closure versus Gastric Resection for Perforated Gastric Ulcer - A Surgical Debate. (United States)

    Gachabayov, Mahir; Babyshin, Valentin; Durymanov, Oleg; Neronov, Dmitriy


    Perforated gastric ulcer is one of the most life-threatening complications of peptic ulcer disease with high morbidity and mortality rates. The surgical strategy for gastric perforation in contrast with duodenal perforations often requires consilium and intraoperative debates. The subject of the debate is a 59-year-old male patient who presented with perforated giant gastric ulcer complicated by generalized peritonitis and severe sepsis. The debate is based on a systematized table dividing all factors into three groups and putting them on surgical scales. Pathology-related factors influencing the decision-making are size and site of perforation, local tissue inflammation, signs of malignancy, simultaneous complications of peptic ulcer, peritonitis, and sepsis. Besides these factors, patient- and healthcare-related factors should also be considered.

  12. A Fast and Accurate Scheme for Sea Ice Dynamics with a Stochastic Subgrid Model (United States)

    Seinen, C.; Khouider, B.


    Sea ice physics is a very complex process occurring over a wide range of scales; such as local melting or large scale drift. At the current grid resolution of Global Climate Models (GCMs), we are able to resolve large scale sea ice dynamics but uncertainty remains due to subgrid physics and potential dynamic feedback, especially due to the formation of melt ponds. Recent work in atmospheric science has shown success of Markov Jump stochastic subgrid models in the representation of clouds and convection and their feedback into the large scales. There has been a push to implement these methods in other parts of the Earth System and for the cryosphere in particular but in order to test these methods, efficient and accurate solvers are required for the resolved large scale sea-ice dynamics. We present a second order accurate scheme, in both time and space, for the sea ice momentum equation (SIME) with a Jacobian Free Newton Krylov (JFNK) solver. SIME is a highly nonlinear equation due to sea ice rheology terms appearing in the stress tensor. The most commonly accepted formulation, introduced by Hibler, allows sea-ice to resist significant stresses in compression but significantly less in tension. The relationship also leads to large changes in internal stresses from small changes in velocity fields. These non-linearities have resulted in the use of implicit methods for SIME and a JFNK solver was recently introduced and used to gain efficiency. However, the method used so far is only first order accurate in time. Here we expand the JFNK approach to a Crank-Nicholson discretization of SIME. This fully second order scheme is achieved with no increase in computational cost and will allow efficient testing and development of subgrid stochastic models of sea ice in the near future.

  13. Use of fundamental condensation heat transfer experiments for the development of a sub-grid liquid jet condensation model

    Energy Technology Data Exchange (ETDEWEB)

    Buschman, Francis X., E-mail:; Aumiller, David L.


    Highlights: • Direct contact condensation data on liquid jets up to 1.7 MPa in pure steam and in the presence of noncondensable gas. • Identified a pressure effect on the impact of noncondensables to suppress condensation heat transfer not captured in existing data or correlations. • Pure steam data is used to develop a new correlation for condensation heat transfer on subcooled liquid jets. • Noncondensable data used to develop a modification to the renewal time estimate used in the Young and Bajorek correlation for condensation suppression in the presence of noncondensables. • A jet injection boundary condition, using a sub-grid jet condensation model, is developed for COBRA-IE which provides a more detailed estimate of the condensation rate on the liquid jet and allows the use of jet specific closure relationships. - Abstract: Condensation on liquid jets is an important phenomenon for many different facets of nuclear power plant transients and analyses such as containment spray cooling. An experimental facility constructed at the Pennsylvania State University, the High Pressure Liquid Jet Condensation Heat Transfer facility (HPLJCHT), has been used to perform steady-state condensation heat transfer experiments in which the temperature of the liquid jet is measured at different axial locations allowing the condensation rate to be determined over the jet length. Test data have been obtained in a pure steam environment and with varying concentrations of noncondensable gas. This data extends the available jet condensation data from near atmospheric pressure up to a pressure of 1.7 MPa. An empirical correlation for the liquid side condensation heat transfer coefficient has been developed based on the data obtained in pure steam. The data obtained with noncondensable gas were used to develop a correlation for the renewal time as used in the condensation suppression model developed by Young and Bajorek. This paper describes a new sub-grid liquid jet

  14. A distributed Grid-Xinanjiang model with integration of subgrid variability of soil storage capacity

    Directory of Open Access Journals (Sweden)

    Wei-jian Guo


    Full Text Available Realistic hydrological response is sensitive to the spatial variability of landscape properties. For a grid-based distributed rainfall-runoff model with a hypothesis of a uniform grid, the high-frequency information within a grid cell will be gradually lost as the resolution of the digital elevation model (DEM grows coarser. Therefore, the performance of a hydrological model is usually scale-dependent. This study used the Grid-Xinanjiang (GXAJ model as an example to investigate the effects of subgrid variability on hydrological response at different scales. With the aim of producing a more reasonable hydrological response and spatial description of the landscape properties, a new distributed rainfall-runoff model integrating the subgrid variability (the GXAJSV model was developed. In this model, the topographic index is used as an auxiliary variable correlated with the soil storage capacity. The incomplete beta distribution is suggested for simulating the probability distribution of the soil storage capacity within the raster grid. The Yaogu Basin in China was selected for model calibration and validation at different spatial scales. Results demonstrated that the proposed model can effectively eliminate the scale dependence of the GXAJ model and produce a more reasonable hydrological response.

  15. Combination of Lidar Elevations, Bathymetric Data, and Urban Infrastructure in a Sub-Grid Model for Predicting Inundation in New York City during Hurricane Sandy

    CERN Document Server

    Loftis, Jon Derek; Hamilton, Stuart E; Forrest, David R


    We present the geospatial methods in conjunction with results of a newly developed storm surge and sub-grid inundation model which was applied in New York City during Hurricane Sandy in 2012. Sub-grid modeling takes a novel approach for partial wetting and drying within grid cells, eschewing the conventional hydrodynamic modeling method by nesting a sub-grid containing high-resolution lidar topography and fine scale bathymetry within each computational grid cell. In doing so, the sub-grid modeling method is heavily dependent on building and street configuration provided by the DEM. The results of spatial comparisons between the sub-grid model and FEMA's maximum inundation extents in New York City yielded an unparalleled absolute mean distance difference of 38m and an average of 75% areal spatial match. An in-depth error analysis reveals that the modeled extent contour is well correlated with the FEMA extent contour in most areas, except in several distinct areas where differences in special features cause sig...

  16. Eigenspace perturbations for structural uncertainty estimation of turbulence closure models (United States)

    Jofre, Lluis; Mishra, Aashwin; Iaccarino, Gianluca


    With the present state of computational resources, a purely numerical resolution of turbulent flows encountered in engineering applications is not viable. Consequently, investigations into turbulence rely on various degrees of modeling. Archetypal amongst these variable resolution approaches would be RANS models in two-equation closures, and subgrid-scale models in LES. However, owing to the simplifications introduced during model formulation, the fidelity of all such models is limited, and therefore the explicit quantification of the predictive uncertainty is essential. In such scenario, the ideal uncertainty estimation procedure must be agnostic to modeling resolution, methodology, and the nature or level of the model filter. The procedure should be able to give reliable prediction intervals for different Quantities of Interest, over varied flows and flow conditions, and at diametric levels of modeling resolution. In this talk, we present and substantiate the Eigenspace perturbation framework as an uncertainty estimation paradigm that meets these criteria. Commencing from a broad overview, we outline the details of this framework at different modeling resolution. Thence, using benchmark flows, along with engineering problems, the efficacy of this procedure is established. This research was partially supported by NNSA under the Predictive Science Academic Alliance Program (PSAAP) II, and by DARPA under the Enabling Quantification of Uncertainty in Physical Systems (EQUiPS) project (technical monitor: Dr Fariba Fahroo).

  17. Statistical Mechanics-based Closures for Large Eddy Simulations (United States)

    Parish, Eric; Duraisamy, Karthik; Gouasmi, Ayoub; Computational Aerosciences Laboratory Team


    The simulation of high Reynolds-number fluid flows is made challenging by the presence of an enormous range of temporal and spatial scales. The Mori-Zwanzig (MZ) formalism originates from non-equilibrium statistical mechanics and provides a formal backdrop for the construction of coarse-grained models. In this work, a class of models inspired from the Mori-Zwanzig formalism are applied to turbulent flows. The MZ-models are derived directly from the governing equations and require minimal heuristics. The resulting closures are non-Markovian and are akin to modeling the divergence of the sub-grid stress. Non-local temporal effects are captured through a finite memory approximation of the MZ memory kernel. Numerical simulations of rotating homogeneous turbulence and turbulent channel flow are presented. The MZ-based models are shown to accurately characterize the behavior of the unresolved dynamics associated energy transfer mechanisms. This work was supported in part by AFOSR under the project "LES Modeling of Non-local effects using Statistical Coarse-graining" with Dr. Jean-Luc Cambier as the technical monitor.

  18. Acceleration of inertial particles in wall bounded flows: DNS and LES with stochastic modelling of the subgrid acceleration

    Energy Technology Data Exchange (ETDEWEB)

    Zamansky, Remi; Vinkovic, Ivana; Gorokhovski, Mikhael, E-mail: [Laboratoire de Mecanique des Fluides et d' Acoustique CNRS UMR 5509 Ecole Centrale de Lyon, 36, av. Guy de Collongue, 69134 Ecully Cedex (France)


    Inertial particle acceleration statistics are analyzed using DNS for turbulent channel flow. Along with effects recognized in homogeneous isotropic turbulence, an additional effect is observed due to high and low speed vortical structures aligned with the channel wall. In response to those structures, particles with moderate inertia experience strong longitudinal acceleration variations. DNS is also used in order to assess LES-SSAM (Subgrid Stochastic Acceleration Model), in which an approximation to the instantaneous non-filtered velocity field is given by simulation of both, filtered and residual, accelerations. This approach allow to have access to the intermittency of the flow at subgrid scale. Advantages of LES-SSAM in predicting particle dynamics in the channel flow at a high Reynolds number are shown.

  19. Autonomous Operation of Hybrid Microgrid With AC and DC Subgrids

    DEFF Research Database (Denmark)

    Chiang Loh, Poh; Li, Ding; Kang Chai, Yi


    This paper investigates on power-sharing issues of an autonomous hybrid microgrid. Unlike existing microgrids which are purely ac, the hybrid microgrid studied here comprises dc and ac subgrids interconnected by power electronic interfaces. The main challenge here is to manage power flows among all...... converters. Suitable control and normalization schemes are now developed for controlling them with the overall hybrid microgrid performance already verified in simulation and experiment....

  20. Operational forecasting with the subgrid technique on the Elbe Estuary (United States)

    Sehili, Aissa


    Modern remote sensing technologies can deliver very detailed land surface height data that should be considered for more accurate simulations. In that case, and even if some compromise is made with regard to grid resolution of an unstructured grid, simulations still will require large grids which can be computationally very demanding. The subgrid technique, first published by Casulli (2009), is based on the idea of making use of the available detailed subgrid bathymetric information while performing computations on relatively coarse grids permitting large time steps. Consequently, accuracy and efficiency are drastically enhanced if compared to the classical linear method, where the underlying bathymetry is solely discretized by the computational grid. The algorithm guarantees rigorous mass conservation and nonnegative water depths for any time step size. Computational grid-cells are permitted to be wet, partially wet or dry and no drying threshold is needed. The subgrid technique is used in an operational forecast model for water level, current velocity, salinity and temperature of the Elbe estuary in Germany. Comparison is performed with the comparatively highly resolved classical unstructured grid model UnTRIM. The daily meteorological forcing data are delivered by the German Weather Service (DWD) using the ICON-EU model. Open boundary data are delivered by the coastal model BSHcmod of the German Federal Maritime and Hydrographic Agency (BSH). Comparison of predicted water levels between classical and subgrid model shows a very good agreement. The speedup in computational performance due to the use of the subgrid technique is about a factor of 20. A typical daily forecast can be carried out within less than 10 minutes on standard PC-like hardware. The model is capable of permanently delivering highly resolved temporal and spatial information on water level, current velocity, salinity and temperature for the whole estuary. The model offers also the possibility to

  1. Restaurant closures

    CERN Document Server

    Novae Restauration


    Christmas Restaurant closures Please note that the Restaurant 1 and Restaurant 3 will be closed from Friday, 21 December at 5 p.m. to Sunday, 6 January, inclusive. They will reopen on Monday, 7 January 2013.   Restaurant 2 closure for renovation To meet greater demand and to modernize its infrastructure, Restaurant 2 will be closed from Monday, 17 December. On Monday, 14 January 2013, Sophie Vuetaz’s team will welcome you to a renovated self-service area on the 1st floor. The selections on the ground floor will also be expanded to include pasta and pizza, as well as snacks to eat in or take away. To ensure a continuity of service, we suggest you take your break at Restaurant 1 or Restaurant 3 (Prévessin).

  2. On the development of a subgrid CFD model for fire extinguishment

    Energy Technology Data Exchange (ETDEWEB)



    A subgrid model is presented for use in CFD fire simulations to account for thermal suppressants and strain. The extinguishment criteria is based on the ratio of a local fluid-mechanics time-scale to a local chemical time-scale compared to an empirically-determined critical Damkohler number. Local extinction occurs if this time scale is exceeded, global fire extinguishment occurs when local extinction has occurred for all combusting cells. The fluid mechanics time scale is based on the Kolmogorov time scale and the chemical time scale is based on blowout of a perfectly stirred reactor. The input to the reactor is based on cell averaged temperatures, assumed stoichiometric fuel/air composition, and cell averaged suppressant concentrations including combustion products. A detailed chemical mechanism is employed. The chemical time-scale is precalculated and mixing rules are used to reduce the composition space that must be parameterized. Comparisons with experimental data for fire extinguishment in a flame-stabilizing, backward-facing step geometry indicates that the model is conservative for this condition.

  3. CLOSURE DEVICE (United States)

    Linzell, S.M.; Dorcy, D.J.


    A quick opening type of stuffing box employing two banks of rotatable shoes, each of which has a caraming action that forces a neoprene sealing surface against a pipe or rod where it passes through a wall is presented. A ring having a handle or wrench attached is placed eccentric to and between the two banks of shoes. Head bolts from the shoes fit into slots in this ring, which are so arranged that when the ring is rotated a quarter turn in one direction the shoes are thrust inwardly to cramp the neopnrene about the pipe, malting a tight seal. Moving the ring in the reverse direction moves the shoes outwardly and frees the pipe which then may be readily removed from the stuffing box. This device has particular application as a closure for the end of a coolant tube of a neutronic reactor.

  4. Resolving terrestrial ecosystem processes along a subgrid topographic gradient for an earth-system model (United States)

    Subin, Z M; Milly, Paul C.D.; Sulman, B N; Malyshev, Sergey; Shevliakova, E


    Soil moisture is a crucial control on surface water and energy fluxes, vegetation, and soil carbon cycling. Earth-system models (ESMs) generally represent an areal-average soil-moisture state in gridcells at scales of 50–200 km and as a result are not able to capture the nonlinear effects of topographically-controlled subgrid heterogeneity in soil moisture, in particular where wetlands are present. We addressed this deficiency by building a subgrid representation of hillslope-scale topographic gradients, TiHy (Tiled-hillslope Hydrology), into the Geophysical Fluid Dynamics Laboratory (GFDL) land model (LM3). LM3-TiHy models one or more representative hillslope geometries for each gridcell by discretizing them into land model tiles hydrologically coupled along an upland-to-lowland gradient. Each tile has its own surface fluxes, vegetation, and vertically-resolved state variables for soil physics and biogeochemistry. LM3-TiHy simulates a gradient in soil moisture and water-table depth between uplands and lowlands in each gridcell. Three hillslope hydrological regimes appear in non-permafrost regions in the model: wet and poorly-drained, wet and well-drained, and dry; with large, small, and zero wetland area predicted, respectively. Compared to the untiled LM3 in stand-alone experiments, LM3-TiHy simulates similar surface energy and water fluxes in the gridcell-mean. However, in marginally wet regions around the globe, LM3-TiHy simulates shallow groundwater in lowlands, leading to higher evapotranspiration, lower surface temperature, and higher leaf area compared to uplands in the same gridcells. Moreover, more than four-fold larger soil carbon concentrations are simulated globally in lowlands as compared with uplands. We compared water-table depths to those simulated by a recent global model-observational synthesis, and we compared wetland and inundated areas diagnosed from the model to observational datasets. The comparisons demonstrate that LM3-TiHy has the

  5. Full closure strategic analysis. (United States)


    The full closure strategic analysis was conducted to create a decision process whereby full roadway : closures for construction and maintenance activities can be evaluated and approved or denied by CDOT : Traffic personnel. The study reviewed current...

  6. Quantification of marine aerosol subgrid variability and its correlation with clouds based on high-resolution regional modeling: Quantifying Aerosol Subgrid Variability

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Guangxing; Qian, Yun; Yan, Huiping; Zhao, Chun; Ghan, Steven J.; Easter, Richard C.; Zhang, Kai


    One limitation of most global climate models (GCMs) is that with the horizontal resolutions they typically employ, they cannot resolve the subgrid variability (SGV) of clouds and aerosols, adding extra uncertainties to the aerosol radiative forcing estimation. To inform the development of an aerosol subgrid variability parameterization, here we analyze the aerosol SGV over the southern Pacific Ocean simulated by the high-resolution Weather Research and Forecasting model coupled to Chemistry. We find that within a typical GCM grid, the aerosol mass subgrid standard deviation is 15% of the grid-box mean mass near the surface on a 1 month mean basis. The fraction can increase to 50% in the free troposphere. The relationships between the sea-salt mass concentration, meteorological variables, and sea-salt emission rate are investigated in both the clear and cloudy portion. Under clear-sky conditions, marine aerosol subgrid standard deviation is highly correlated with the standard deviations of vertical velocity, cloud water mixing ratio, and sea-salt emission rates near the surface. It is also strongly connected to the grid box mean aerosol in the free troposphere (between 2 km and 4 km). In the cloudy area, interstitial sea-salt aerosol mass concentrations are smaller, but higher correlation is found between the subgrid standard deviations of aerosol mass and vertical velocity. Additionally, we find that decreasing the model grid resolution can reduce the marine aerosol SGV but strengthen the correlations between the aerosol SGV and the total water mixing ratio (sum of water vapor, cloud liquid, and cloud ice mixing ratios).

  7. Closure The Definitive Guide

    CERN Document Server

    Bolin, Michael


    If you're ready to use Closure to build rich web applications with JavaScript, this hands-on guide has precisely what you need to learn this suite of tools in depth. Closure makes it easy for experienced JavaScript developers to write and maintain large and complex codebases -- as Google has demonstrated by using Closure with Gmail, Google Docs, and Google Maps. Author and Closure contributor Michael Bolin has included numerous code examples and best practices, as well as valuable information not available publicly until now. You'll learn all about Closure's Library, Compiler, Templates, tes

  8. Aerosol indirect effects in the ECHAM5-HAM2 climate model with subgrid cloud microphysics in a stochastic framework (United States)

    Tonttila, Juha; Räisänen, Petri; Järvinen, Heikki


    Representing cloud properties in global climate models remains a challenging topic, which to a large extent is due to cloud processes acting on spatial scales much smaller than the typical model grid resolution. Several attempts have been made to alleviate this problem. One such method was introduced in the ECHAM5-HAM2 climate model by Tonttila et al. (2013), where cloud microphysical properties, along with the processes of cloud droplet activation and autoconversion, were computed using an ensemble of stochastic subcolumns within the climate model grid columns. Moreover, the subcolumns were sampled for radiative transfer using the Monte Carlo Independent Column Approximation approach. The same model version is used in this work (Tonttila et al. 2014), where 5-year nudged integrations are performed with a series of different model configurations. Each run is performed twice, once with pre-industrial (PI, year 1750) aerosol emission conditions and once with present-day (PD, year 2000) conditions, based on the AEROCOM emission inventories. The differences between PI and PD simulations are used to estimate the impact of anthropogenic aerosols on clouds and the aerosol indirect effect (AIE). One of the key results is that when both cloud activation and autoconversion are computed in the subcolumn space, the aerosol-induced PI-to-PD change in the global-mean liquid water path is up to 19 % smaller than in the reference with grid-scale computations. Together with similar changes in the cloud droplet number concentration, this influences the cloud radiative effects and thus the AIE, which is estimated as the difference in the net cloud radiative effect between PI and PD conditions. Accordingly, the AIE is reduced by 14 %, from 1.59 W m-2 in the reference model version to 1.37 W m-2 in the experimental model configuration. The results of this work explicitly show that careful consideration of the subgrid variability in cloud microphysical properties and consistent

  9. The effects of the sub-grid variability of soil and land cover data on agricultural droughts in Germany (United States)

    Kumar, Rohini; Samaniego, Luis; Zink, Matthias


    Simulated soil moisture from land surface or water balance models is increasingly used to characterize and/or monitor the development of agricultural droughts at regional and global scales (e.g. NLADS, EDO, GLDAS). The skill of these models to accurately replicate hydrologic fluxes and state variables is strongly dependent on the quality meteorological forcings, the conceptualization of dominant processes, and the parameterization scheme used to incorporate the variability of land surface properties (e.g. soil, topography, and vegetation) at a coarser spatial resolutions (e.g. at least 4 km). The goal of this study is to analyze the effects of the sub-grid variability of soil texture and land cover properties on agricultural drought statistics such as duration, severity, and areal extent. For this purpose, a process based mesoscale hydrologic model (mHM) is used to create two sets of daily soil moisture fields over Germany at the spatial resolution of (4 × 4) km2 from 1950 to 2011. These simulations differ from each other only on the manner in which the land surface properties are accounted within the model. In the first set, soil moisture fields are obtained with the multiscale parameter regionalization (MPR) scheme (Samaniego, et. al. 2010, Kumar et. al. 2012), which explicitly takes the sub-grid variability of soil texture and land cover properties into account. In the second set, on the contrary, a single dominant soil and land cover class is used for ever grid cell at 4 km. Within each set, the propagation of the parameter uncertainty into the soil moisture simulations is also evaluated using an ensemble of 100 best global parameter sets of mHM (Samaniego, et. al. 2012). To ensure comparability, both sets of this ensemble simulations are forced with the same fields of meteorological variables (e.g., precipitation, temperature, and potential evapotranspiration). Results indicate that both sets of model simulations, with and without the sub-grid variability of

  10. Sub-Grid Modeling of Electrokinetic Effects in Micro Flows (United States)

    Chen, C. P.


    Advances in micro-fabrication processes have generated tremendous interests in miniaturizing chemical and biomedical analyses into integrated microsystems (Lab-on-Chip devices). To successfully design and operate the micro fluidics system, it is essential to understand the fundamental fluid flow phenomena when channel sizes are shrink to micron or even nano dimensions. One important phenomenon is the electro kinetic effect in micro/nano channels due to the existence of the electrical double layer (EDL) near a solid-liquid interface. Not only EDL is responsible for electro-osmosis pumping when an electric field parallel to the surface is imposed, EDL also causes extra flow resistance (the electro-viscous effect) and flow anomaly (such as early transition from laminar to turbulent flow) observed in pressure-driven microchannel flows. Modeling and simulation of electro-kinetic effects on micro flows poses significant numerical challenge due to the fact that the sizes of the double layer (10 nm up to microns) are very thin compared to channel width (can be up to 100 s of m). Since the typical thickness of the double layer is extremely small compared to the channel width, it would be computationally very costly to capture the velocity profile inside the double layer by placing sufficient number of grid cells in the layer to resolve the velocity changes, especially in complex, 3-d geometries. Existing approaches using "slip" wall velocity and augmented double layer are difficult to use when the flow geometry is complicated, e.g. flow in a T-junction, X-junction, etc. In order to overcome the difficulties arising from those two approaches, we have developed a sub-grid integration method to properly account for the physics of the double layer. The integration approach can be used on simple or complicated flow geometries. Resolution of the double layer is not needed in this approach, and the effects of the double layer can be accounted for at the same time. With this

  11. Yucca Mountain Waste Package Closure System

    Energy Technology Data Exchange (ETDEWEB)

    Herschel Smartt; Arthur Watkins; David Pace; Rodney Bitsoi; Eric Larsen; Timothy McJunkin; Charles Tolle


    The current disposal path for high-level waste is to place the material into secure waste packages that are inserted into a repository. The Idaho National Laboratory has been tasked with the development, design, and demonstration of the waste package closure system for the repository project. The closure system design includes welding three lids and a purge port cap, four methods of nondestructive examination, and evacuation and backfill of the waste package, all performed in a remote environment. A demonstration of the closure system will be performed with a full-scale waste package.

  12. Yucca Mountain Waste Package Closure System

    Energy Technology Data Exchange (ETDEWEB)

    shelton-davis; Colleen Shelton-Davis; Greg Housley


    The current disposal path for high-level waste is to place the material into secure waste packages that are inserted into a repository. The Idaho National Laboratory has been tasked with the development, design, and demonstration of the waste package closure system for the repository project. The closure system design includes welding three lids and a purge port cap, four methods of nondestructive examination, and evacuation and backfill of the waste package, all performed in a remote environment. A demonstration of the closure system will be performed with a full-scale waste package.

  13. The Storm Surge and Sub-Grid Inundation Modeling in New York City during Hurricane Sandy

    Directory of Open Access Journals (Sweden)

    Harry V. Wang


    Full Text Available Hurricane Sandy inflicted heavy damage in New York City and the New Jersey coast as the second costliest storm in history. A large-scale, unstructured grid storm tide model, Semi-implicit Eulerian Lagrangian Finite Element (SELFE, was used to hindcast water level variation during Hurricane Sandy in the mid-Atlantic portion of the U.S. East Coast. The model was forced by eight tidal constituents at the model’s open boundary, 1500 km away from the coast, and the wind and pressure fields from atmospheric model Regional Atmospheric Modeling System (RAMS provided by Weatherflow Inc. The comparisons of the modeled storm tide with the NOAA gauge stations from Montauk, NY, Long Island Sound, encompassing New York Harbor, Atlantic City, NJ, to Duck, NC, were in good agreement, with an overall root mean square error and relative error in the order of 15–20 cm and 5%–7%, respectively. Furthermore, using large-scale model outputs as the boundary conditions, a separate sub-grid model that incorporates LIDAR data for the major portion of the New York City was also set up to investigate the detailed inundation process. The model results compared favorably with USGS’ Hurricane Sandy Mapper database in terms of its timing, local inundation area, and the depth of the flooding water. The street-level inundation with water bypassing the city building was created and the maximum extent of horizontal inundation was calculated, which was within 30 m of the data-derived estimate by USGS.

  14. Enhancing Representation of Subgrid Land Surface Characteristics in the Community Land Model (United States)

    Ke, Y.; Coleman, A.; Leung, L.; Huang, M.; Li, H.; Wigmosta, M. S.


    The Community Land Model (CLM) is the land surface model used in the Community Earth System Model (CESM). In CLM each grid cell is composed of subgrid land units, snow/soil columns and plant functional types (PFTs). In the current version of CLM (CLM4.0), land surface parameters such as vegetated/non-vegetated land cover and surface characteristics including fractional glacier, lake, wetland, urban area, and PFT, and its associated leaf area index (LAI), stem area index (SAI), and canopy top and bottom heights are provided at 0.5° or coarser resolution. This study aims to enhance the representation of the land surface data by (1) creating higher resolution (0.05° or higher) global land surface parameters, and (2) developing an effective and accurate subgrid classification scheme for elevation and PFTs so that variations of land surface processes due to the subgrid distribution of PFTs and elevation can be represented in CLM. To achieve higher-resolution global land surface parameters, MODIS 500m land cover product (MCD12Q1) collected in 2005 was used to generate percentage of glacier, lake, wetland, and urban area and fractional PFTs at 0.05° resolution. Spatially and temporally continuous and consistent global LAI data re-processed and improved from MOD15A2 (, combined with the PFT data, was used to create LAI, SAI, and, canopy top and bottom height data. 30-second soil texture data was obtained from a hybrid 30-second State Soil Geographic Database (STATSGO) and the 5-minute Food and Agriculture Organization two-layer 16-category soil texture dataset. The relationship between global distribution of PFTs and 1-km resolution elevation data is being analyzed to develop a subgrid classification of PFT and elevation. Statistical analysis is being conducted to compare different subgrid classification methods to select a method that explains the highest percentage of subgrid variance in both PFT and elevation distribution

  15. Eyelid closure at death

    Directory of Open Access Journals (Sweden)

    A D Macleod


    Full Text Available Aim: To observe the incidence of full or partial eyelid closure at death. Materials and Methods: The presence of ptosis was recorded in 100 consecutive hospice patient deaths. Results: Majority (63% of the patients died with their eyes fully closed, however, 37% had bilateral ptosis at death, with incomplete eye closure. In this study, central nervous system tumor involvement and/or acute hepatic encephalopathy appeared to be pre-mortem risk factors of bilateral ptosis at death. Conclusion: Organicity and not psychogenicity is, therefore, the likely etiology of failure of full eyelid closure at death.

  16. Sternal exploration or closure (United States)

    You may have already been receiving wound care or treatment and antibiotics. There are two main reasons for doing exploration and closure procedures for the chest wound after heart surgery: Get rid ...

  17. Crystal structures of yeast beta-alanine synthase complexes reveal the mode of substrate binding and large scale domain closure movements. (United States)

    Lundgren, Stina; Andersen, Birgit; Piskur, Jure; Dobritzsch, Doreen


    Beta-alanine synthase is the final enzyme of the reductive pyrimidine catabolic pathway, which is responsible for the breakdown of uracil and thymine in higher organisms. The fold of the homodimeric enzyme from the yeast Saccharomyces kluyveri identifies it as a member of the AcyI/M20 family of metallopeptidases. Its subunit consists of a catalytic domain harboring a di-zinc center and a smaller dimerization domain. The present site-directed mutagenesis studies identify Glu(159) and Arg(322) as crucial for catalysis and His(262) and His(397) as functionally important but not essential. We determined the crystal structures of wild-type beta-alanine synthase in complex with the reaction product beta-alanine, and of the mutant E159A with the substrate N-carbamyl-beta-alanine, revealing the closed state of a dimeric AcyI/M20 metallopeptidase-like enzyme. Subunit closure is achieved by a approximately 30 degrees rigid body domain rotation, which completes the active site by integration of substrate binding residues that belong to the dimerization domain of the same or the partner subunit. Substrate binding is achieved via a salt bridge, a number of hydrogen bonds, and coordination to one of the zinc ions of the di-metal center.

  18. A global data set of soil hydraulic properties and sub-grid variability of soil water retention and hydraulic conductivity curves (United States)

    Montzka, Carsten; Herbst, Michael; Weihermüller, Lutz; Verhoef, Anne; Vereecken, Harry


    Agroecosystem models, regional and global climate models, and numerical weather prediction models require adequate parameterization of soil hydraulic properties. These properties are fundamental for describing and predicting water and energy exchange processes at the transition zone between solid earth and atmosphere, and regulate evapotranspiration, infiltration and runoff generation. Hydraulic parameters describing the soil water retention (WRC) and hydraulic conductivity (HCC) curves are typically derived from soil texture via pedotransfer functions (PTFs). Resampling of those parameters for specific model grids is typically performed by different aggregation approaches such a spatial averaging and the use of dominant textural properties or soil classes. These aggregation approaches introduce uncertainty, bias and parameter inconsistencies throughout spatial scales due to nonlinear relationships between hydraulic parameters and soil texture. Therefore, we present a method to scale hydraulic parameters to individual model grids and provide a global data set that overcomes the mentioned problems. The approach is based on Miller-Miller scaling in the relaxed form by Warrick, that fits the parameters of the WRC through all sub-grid WRCs to provide an effective parameterization for the grid cell at model resolution; at the same time it preserves the information of sub-grid variability of the water retention curve by deriving local scaling parameters. Based on the Mualem-van Genuchten approach we also derive the unsaturated hydraulic conductivity from the water retention functions, thereby assuming that the local parameters are also valid for this function. In addition, via the Warrick scaling parameter λ, information on global sub-grid scaling variance is given that enables modellers to improve dynamical downscaling of (regional) climate models or to perturb hydraulic parameters for model ensemble output generation. The present analysis is based on the ROSETTA PTF

  19. A global data set of soil hydraulic properties and sub-grid variability of soil water retention and hydraulic conductivity curves

    Directory of Open Access Journals (Sweden)

    C. Montzka


    Full Text Available Agroecosystem models, regional and global climate models, and numerical weather prediction models require adequate parameterization of soil hydraulic properties. These properties are fundamental for describing and predicting water and energy exchange processes at the transition zone between solid earth and atmosphere, and regulate evapotranspiration, infiltration and runoff generation. Hydraulic parameters describing the soil water retention (WRC and hydraulic conductivity (HCC curves are typically derived from soil texture via pedotransfer functions (PTFs. Resampling of those parameters for specific model grids is typically performed by different aggregation approaches such a spatial averaging and the use of dominant textural properties or soil classes. These aggregation approaches introduce uncertainty, bias and parameter inconsistencies throughout spatial scales due to nonlinear relationships between hydraulic parameters and soil texture. Therefore, we present a method to scale hydraulic parameters to individual model grids and provide a global data set that overcomes the mentioned problems. The approach is based on Miller–Miller scaling in the relaxed form by Warrick, that fits the parameters of the WRC through all sub-grid WRCs to provide an effective parameterization for the grid cell at model resolution; at the same time it preserves the information of sub-grid variability of the water retention curve by deriving local scaling parameters. Based on the Mualem–van Genuchten approach we also derive the unsaturated hydraulic conductivity from the water retention functions, thereby assuming that the local parameters are also valid for this function. In addition, via the Warrick scaling parameter λ, information on global sub-grid scaling variance is given that enables modellers to improve dynamical downscaling of (regional climate models or to perturb hydraulic parameters for model ensemble output generation. The present analysis is based

  20. Autonomous Operation of Hybrid Microgrid with AC and DC Sub-Grids

    DEFF Research Database (Denmark)

    Loh, Poh Chiang; Blaabjerg, Frede


    This paper investigates on the active and reactive power sharing of an autonomous hybrid microgrid. Unlike existing microgrids which are purely ac, the hybrid microgrid studied here comprises dc and ac sub-grids, interconnected by power electronic interfaces. The main challenge here is to manage...... the power flow among all the sources distributed throughout the two types of sub-grids, which certainly is tougher than previous efforts developed for only either ac or dc microgrid. This wider scope of control has not yet been investigated, and would certainly rely on the coordinated operation of dc...... sources, ac sources and interlinking converters. Suitable control and normalization schemes are therefore developed for controlling them with results presented for showing the overall performance of the hybrid microgrid....

  1. Analysis of subgrid models of heat convection by symmetry group theory (United States)

    Razafindralandy, Dina; Hamdouni, Aziz


    Symmetries, i.e. transformations which leave the set of the solutions of the Navier-Stokes equations unchanged, play an important role in turbulence (conservation laws, wall laws, …). They should not be destroyed by turbulence models. The symmetries of the heat convection equations are then presented, for a non-isothermal fluid. Next, common subgrid stress tensor and flux models are analyzed, using the symmetry approach. To cite this article: D. Razafindralandy, A. Hamdouni, C. R. Mecanique 335 (2007).

  2. Tank closure reducing grout

    Energy Technology Data Exchange (ETDEWEB)

    Caldwell, T.B.


    A reducing grout has been developed for closing high level waste tanks at the Savannah River Site in Aiken, South Carolina. The grout has a low redox potential, which minimizes the mobility of Sr{sup 90}, the radionuclide with the highest dose potential after closure. The grout also has a high pH which reduces the solubility of the plutonium isotopes. The grout has a high compressive strength and low permeability, which enhances its ability to limit the migration of contaminants after closure. The grout was designed and tested by Construction Technology Laboratories, Inc. Placement methods were developed by the Savannah River Site personnel.

  3. 40 CFR 264.113 - Closure; time allowed for closure. (United States)


    ... corrective action program, compile all ground-water monitoring data, and evaluate the effect of the continued... assurance for closure and post-closure care as necessary and appropriate, to reflect any changes due to the presence of hazardous constituents in the non-hazardous wastes, and changes in closure activities...

  4. ROCKET PORT CLOSURE (United States)

    Mattingly, J.T.


    This invention provides a simple pressure-actuated closure whereby windowless observation ports are opened to the atmosphere at preselected altitudes. The closure comprises a disk which seals a windowless observation port in rocket hull. An evacuated instrument compartment is affixed to the rocket hull adjacent the inner surface of the disk, while the outer disk surface is exposed to the atmosphere through which the rocket is traveling. The pressure differential between the evacuated instrument compartment and the relatively high pressure external atmosphere forces the disk against the edge of the observation port, thereby effecting a tight seai. The instrument compartment is evacuated to a pressure equal to the atmospheric pressure existing at the altitude at which it is desiretl that the closure should open. When the rocket reaches this preselected altitude, the inwardly directed atmospheric force on the disk is just equaled by the residual air pressure force within the instrument compartment. Consequently, the closure disk falls away and uncovers the open observation port. The separation of the disk from the rocket hull actuates a switch which energizes the mechanism of a detecting instrument disposed within the instrument compartment. (AE C)

  5. Mail Office annual closure

    CERN Multimedia


    On the occasion of the annual closure of CERN, there will be no mail distributed on Friday 20 December 2013 but mail will be collected in the morning. Nevertheless, you will still be able to bring your outgoing mail to Building 555-R-002 until 12 noon.  

  6. Ring closure in actin polymers

    Energy Technology Data Exchange (ETDEWEB)

    Sinha, Supurna, E-mail: [Raman Research Institute, Bangalore 560080 (India); Chattopadhyay, Sebanti [Doon University, Dehradun 248001 (India)


    We present an analysis for the ring closure probability of semiflexible polymers within the pure bend Worm Like Chain (WLC) model. The ring closure probability predicted from our analysis can be tested against fluorescent actin cyclization experiments. We also discuss the effect of ring closure on bend angle fluctuations in actin polymers. - Highlights: • Ring closure of biopolymers. • Worm like chain model. • Predictions for experiments.

  7. Ring closure in actin polymers


    Sinha, Supurna; Chattopadhyay, Sebanti


    We present an analysis for the ring closure probability of semiflexible polymers within the pure bend Worm Like Chain (WLC) model. The ring closure probability predicted from our analysis can be tested against fluorescent actin cyclization experiments.We also discuss the effect of ring closure on bend angle fluctuations in actin polymers.

  8. Numerical Dissipation and Subgrid Scale Modeling for Separated Flows at Moderate Reynolds Numbers (United States)

    Cadieux, Francois; Domaradzki, Julian Andrzej


    Flows in rotating machinery, for unmanned and micro aerial vehicles, wind turbines, and propellers consist of different flow regimes. First, a laminar boundary layer is followed by a laminar separation bubble with a shear layer on top of it that experiences transition to turbulence. The separated turbulent flow then reattaches and evolves downstream from a nonequilibrium turbulent boundary layer to an equilibrium one. In previous work, the capability of LES to reduce the resolution requirements down to 1 % of DNS resolution for such flows was demonstrated (Cadieux et al., JFE 136-6). However, under-resolved DNS agreed better with the benchmark DNS than simulations with explicit SGS modeling because numerical dissipation and filtering alone acted as a surrogate SGS dissipation. In the present work numerical viscosity is quantified using a new method proposed recently by Schranner et al. and its effects are analyzed and compared to turbulent eddy viscosities of explicit SGS models. The effect of different SGS models on a simulation of the same flow using a non-dissipative code is also explored. Supported by NSF.

  9. Accounting for subgrid scale topographic variations in flood propagation modeling using MODFLOW

    DEFF Research Database (Denmark)

    Milzow, Christian; Kinzelbach, W.


    To be computationally viable, grid-based spatially distributed hydrological models of large wetlands or floodplains must be set up using relatively large cells (order of hundreds of meters to kilometers). Computational costs are especially high when considering the numerous model runs or model time...

  10. Final Report: Systematic Development of a Subgrid Scaling Framework to Improve Land Simulation

    Energy Technology Data Exchange (ETDEWEB)

    Dickinson, Robert Earl [Univ. of Texas, Austin, TX (United States)


    We carried out research to development improvements of the land component of climate models and to understand the role of land in climate variability and change. A highlight was the development of a 3D canopy radiation model. More than a dozen publications resulted.

  11. How Difficult is it to Reduce Low-Level Cloud Biases With the Higher-Order Turbulence Closure Approach in Climate Models? (United States)

    Xu, Kuan-Man


    Low-level clouds cover nearly half of the Earth and play a critical role in regulating the energy and hydrological cycle. Despite the fact that a great effort has been put to advance the modeling and observational capability in recent years, low-level clouds remains one of the largest uncertainties in the projection of future climate change. Low-level cloud feedbacks dominate the uncertainty in the total cloud feedback in climate sensitivity and projection studies. These clouds are notoriously difficult to simulate in climate models due to its complicated interactions with aerosols, cloud microphysics, boundary-layer turbulence and cloud dynamics. The biases in both low cloud coverage/water content and cloud radiative effects (CREs) remain large. A simultaneous reduction in both cloud and CRE biases remains elusive. This presentation first reviews the effort of implementing the higher-order turbulence closure (HOC) approach to representing subgrid-scale turbulence and low-level cloud processes in climate models. There are two HOCs that have been implemented in climate models. They differ in how many three-order moments are used. The CLUBB are implemented in both CAM5 and GDFL models, which are compared with IPHOC that is implemented in CAM5 by our group. IPHOC uses three third-order moments while CLUBB only uses one third-order moment while both use a joint double-Gaussian distribution to represent the subgrid-scale variability. Despite that HOC is more physically consistent and produces more realistic low-cloud geographic distributions and transitions between cumulus and stratocumulus regimes, GCMs with traditional cloud parameterizations outperform in CREs because tuning of this type of models is more extensively performed than those with HOCs. We perform several tuning experiments with CAM5 implemented with IPHOC in an attempt to produce the nearly balanced global radiative budgets without deteriorating the low-cloud simulation. One of the issues in CAM5-IPHOC

  12. Need for closure and youths' leisure time preferences. (United States)

    Vermeir, Iris; Geuens, Maggie


    The Need for Closure is an individual characteristic which may help explain individual differences in engagement in leisure activities. Both a leisure engagement inventory and a validated Dutch version of the Need for Closure Scale were administered to a convenient sample of 1,035 young adults ages 15 to 24 years of whom 552 were female. Leisure engagement was hypothesized to differ for groups differing in Need for Closure. More specifically, youngsters who score high (versus low) on Need for Closure engaged more in structured, cognitively effortless, and predictable leisure activities like shopping for fun and going to the cinema, while young adults scoring low (versus high) on Need for Closure more often participated in unstructured, unpredictable, cognitively effortful or challenging leisure activities like going to a party, a pub, or a pop concert, idly lazing away, visiting or hosting friends, attending an evening class and playing computer games.

  13. Prolonged Eyelid Closure Episodes during Sleep Deprivation in Professional Drivers. (United States)

    Alvaro, Pasquale K; Jackson, Melinda L; Berlowitz, David J; Swann, Philip; Howard, Mark E


    Real life ocular measures of drowsiness use average blink duration, amplitude and velocity of eyelid movements to reflect drowsiness in drivers. However, averaged data may conceal the variability in duration of eyelid closure episodes, and more prolonged episodes that indicate higher levels of drowsiness. The current study aimed to describe the frequency and duration of prolonged eyelid closure episodes during acute sleep deprivation. Twenty male professional drivers (mean age ± standard deviation = 41.9 ± 8.3 years) were recruited from the Transport Workers Union newsletter and newspaper advertisements in Melbourne, Australia. Each participant underwent 24 hours of sleep deprivation and completed a simulated driving task (AusEd), the Psychomotor Vigilance Task, and the Karolinska Sleepiness Scale. Eyelid closure episodes during the driving task were recorded and analyzed manually from digital video recordings. Eyelid closure episodes increased in frequency and duration with a median of zero s/h of eyelid closure after 3 h increasing to 34 s/h after 23 h awake. Eyelid closure episodes were short and infrequent from 3 to 14 h of wakefulness. After 17 h of sleep deprivation, longer and more frequent eyelid closure episodes began to occur. Episodes lasting from 7 seconds up to 18 seconds developed after 20 h of wakefulness. Length of eyelid closure episodes was moderately to highly correlated with the standard deviation of lateral lane position, braking reaction time, crashes, impaired vigilance, and subjective sleepiness. The frequency and duration of episodes of prolonged eyelid closure increases during acute sleep deprivation, with very prolonged episodes after 17 hours awake. Automated devices that assess drowsiness using averaged measures of eyelid closure episodes need to be able to detect prolonged eyelid closure episodes that occur during more severe sleep deprivation. © 2016 American Academy of Sleep Medicine.

  14. Evaluation of a Sub-Grid Topographic Drag Parameterizations for Modeling Surface Wind Speed During Storms Over Complex Terrain in the Northeast U.S. (United States)

    Frediani, M. E.; Hacker, J.; Anagnostou, E. N.; Hopson, T. M.


    This study aims at improving regional simulation of 10-meter wind speed by verifying PBL schemes for storms at different scales, including convective storms, blizzards, tropical storms and nor'easters over complex terrain in the northeast U.S. We verify a recently proposed sub-grid topographic drag scheme in stormy conditions and compare it with two PBL schemes (Mellor-Yamada and Yonsei University) from WRF-ARW over a region in the Northeast U.S. The scheme was designed to adjust the surface drag over regions with high subgrid-scale topographic variability. The schemes are compared using spatial, temporal, and pattern criteria against surface observations. The spatial and temporal criteria are defined by season, diurnal cycle, and topography; the pattern, is based on clusters derived using clustering analysis. Results show that the drag scheme reduces the positive bias of low wind speeds, but over-corrects the high wind speeds producing a magnitude-increasing negative bias with increasing speed. Both other schemes underestimate the most frequent low-speed mode and overestimate the high-speeds. Error characteristics of all schemes respond to seasonal and diurnal cycle changes. The Topo-wind experiment shows the best agreement with the observation quantiles in summer and fall, the best representation of the diurnal cycle in these seasons, and reduces the bias of all surface stations near the coast. In more stable conditions the Topo-wind scheme shows a larger negative bias. The cluster analysis reveals a correlation between bias and mean speed from the Mellor-Yamada and Yonsei University schemes that is not present when the drag scheme is used. When the drag scheme is used the bias correlates with wind direction; the bias increases when the meridional wind component is negative. This pattern corresponds to trajectories with more land interaction with the highest biases found in northwest circulation clusters.

  15. Summer season | Cafeteria closures

    CERN Multimedia


    Please note the following cafeteria closures over the summer season: Bldg. 54 closed from 29/07/2013 to 06/09/2013. Bldg. 13: closed from 13/07/2013 to 06/09/2013. Restaurant No. 2, table service (brasserie and restaurant): closed from 01/08/2013 to 06/09/2013. Bldg. 864: closed from 29/07/2013 to 06/09/2013. Bldg. 865: closed from 29/07/2013 to 06/09/2013.

  16. Suture Closure versus Non-Closure of Subcutaneous Fat and Cosmetic Outcome after Cesarean Section: A Randomized Controlled Trial.

    Directory of Open Access Journals (Sweden)

    Heinrich Husslein

    Full Text Available To investigate the effect of subcutaneous fat suture closure versus non-closure at cesarean section (CS on long-term cosmetic outcome.Women undergoing planned or unplanned CS were randomized to either subcutaneous fat suture closure or non-closure using a 1∶1 allocation algorithm. Participants and outcome assessors were blinded to group allocation. Scar evaluation was performed after two and six months. Primary outcome measures were Patient and Observer Scar Assessment Scale (POSAS summary scores six months after surgery. Secondary outcome measures were Vancouver Scar Scale (VSS summary scores, retraction of the scar below the level of the surrounding skin, duration of surgery, and development of hematoma, seroma, surgical site infection (SSI or wound disruption. Data were analyzed according to the intention to treat principle.A total of 116 women were randomized and 91 participants, 47 in the closure and 44 in the non-closure group, completed the trial and were analyzed. There were no differences in patient morphometrics or surgery indications between groups. At two and six months no significant differences were found with respect to POSAS or VSS scores between groups. After two months significantly more women in the non-closure group described their scar as being retracted below the level of the skin (36% vs. 15%, p = 0.02 whereas no difference was observed at six months. There were significantly more hematomas in the non-closure (25% compared to the closure group (4% (p = 0.005. There was no difference in duration of surgery, SSI, seroma formation or wound disruption between groups.Suture closure of the subcutaneous fat at CS does not affect long-term cosmetic outcome. (Level I NCT01542346.

  17. Closure modeling using field inversion and machine learning (United States)

    Duraisamy, Karthik


    The recent acceleration in computational power and measurement resolution has made possible the availability of extreme scale simulations and data sets. In this work, a modeling paradigm that seeks to comprehensively harness large scale data is introduced, with the aim of improving closure models. Full-field inversion (in contrast to parameter estimation) is used to obtain corrective, spatially distributed functional terms, offering a route to directly address model-form errors. Once the inference has been performed over a number of problems that are representative of the deficient physics in the closure model, machine learning techniques are used to reconstruct the model corrections in terms of variables that appear in the closure model. These machine-learned functional forms are then used to augment the closure model in predictive computations. The approach is demonstrated to be able to successfully reconstruct functional corrections and yield predictions with quantified uncertainties in a range of turbulent flows.

  18. Nevada Test Site closure program

    Energy Technology Data Exchange (ETDEWEB)

    Shenk, D.P.


    This report is a summary of the history, design and development, procurement, fabrication, installation and operation of the closures used as containment devices on underground nuclear tests at the Nevada Test Site. It also addresses the closure program mothball and start-up procedures. The Closure Program Document Index and equipment inventories, included as appendices, serve as location directories for future document reference and equipment use.

  19. MNC Subsidiary Closure

    DEFF Research Database (Denmark)

    de Faria, Pedro; Sofka, Wolfgang; Torres Preto, Miguel

    We investigate the consequences of MNC subsidiary closures for employees who lose their jobs. We ask to what degree the foreign knowledge that they were exposed to is valued in their new job. We argue theoretically that this foreign knowledge is both valuable and not readily available in the host...... country but is also distant and therefore difficult to absorb. We predict an inverse u-shaped relationship between the exposure to foreign knowledge and the salary in the new job. We empirically support our predictions for a sample of almost 140,000 affected employees in Portugal from 2002 to 2009....

  20. MNC Subsidiary Closure

    DEFF Research Database (Denmark)

    de Faria, Pedro; Preto, Miguel Torres; Sofka, Wolfgang


    We investigate the consequences of MNC subsidiary closures for employees who lose their jobs. We ask to what degree the foreign knowledge that they were exposed to is valued in their new job. We argue theoretically that this foreign knowledge is both valuable and not readily available in the host...... country but is also distant and therefore difficult to absorb. We predict an inverse u-shaped relationship between the exposure to foreign knowledge and the salary in the new job. We empirically support our predictions for a sample of almost 140,000 affected employees in Portugal from 2002 to 2009....

  1. Empirical Correlates of Narrative Closure

    Directory of Open Access Journals (Sweden)

    Tobias Klauk


    Full Text Available This paper presents an experimental investigation of the narratological concept of narrative closure. While narrative closure is a well-studied phenomenon in contemporary narratology, it still lacks a serious empirical foundation. In order to fill that lacuna, we performed a controlled rating experiment aimed at validating some of the properties of narrative closure proposed in the narratological literature. Our results suggest that narrative closure is closely related to two connected properties: to the completeness of the text and to questions left open by the text.

  2. Modelling sub-grid wetland in the ORCHIDEE global land surface model: evaluation against river discharges and remotely sensed data

    Directory of Open Access Journals (Sweden)

    B. Ringeval


    Full Text Available The quality of the global hydrological simulations performed by land surface models (LSMs strongly depends on processes that occur at unresolved spatial scales. Approaches such as TOPMODEL have been developed, which allow soil moisture redistribution within each grid-cell, based upon sub-grid scale topography. Moreover, the coupling between TOPMODEL and a LSM appears as a potential way to simulate wetland extent dynamic and its sensitivity to climate, a recently identified research problem for biogeochemical modelling, including methane emissions. Global evaluation of the coupling between TOPMODEL and an LSM is difficult, and prior attempts have been indirect, based on the evaluation of the simulated river flow. This study presents a new way to evaluate this coupling, within the ORCHIDEE LSM, using remote sensing data of inundated areas. Because of differences in nature between the satellite derived information – inundation extent – and the variable diagnosed by TOPMODEL/ORCHIDEE – area at maximum soil water content, the evaluation focuses on the spatial distribution of these two quantities as well as on their temporal variation. Despite some difficulties in exactly matching observed localized inundated events, we obtain a rather good agreement in the distribution of these two quantities at a global scale. Floodplains are not accounted for in the model, and this is a major limitation. The difficulty of reproducing the year-to-year variability of the observed inundated area (for instance, the decreasing trend by the end of 90s is also underlined. Classical indirect evaluation based on comparison between simulated and observed river flow is also performed and underlines difficulties to simulate river flow after coupling with TOPMODEL. The relationship between inundation and river flow at the basin scale in the model is analyzed, using both methods (evaluation against remote sensing data and river flow. Finally, we discuss the potential of


    Energy Technology Data Exchange (ETDEWEB)

    Lane, J E; Scott, J E; Mathews, S E


    Lawrence Livermore National Laboratory of the University of California (LLNL) operates two Class II surface impoundments that store wastewater that is discharged from a number of buildings located on the Site 300 Facility (Site 300). The wastewater is the by-product of explosives processing. Reduction in the volume of water discharged from these buildings over the past several years has significantly reduced the wastewater storage needs. In addition, the impoundments were constructed in 1984, and the high-density polyethylene (HDPE) geomembrane liners are nearing the end of their service life. The purpose of this project is to clean close the surface impoundments and provide new wastewater storage using portable, above ground storage tanks at six locations. The tanks will be installed prior to closure of the impoundments and will include heaters for allowing evaporation during relatively cool weather. Golder Associates (Golder) has prepared this Final Closure Plan (Closure Plan) on behalf of LLNL to address construction associated with the clean closure of the impoundments. This Closure Plan complies with State Water Resources Control Board (SWRCB) Section 21400 of the California Code of Regulations Title 27 (27 CCR {section}21400). As required by these regulations and guidance, this Plan provides the following information: (1) A site characterization, including the site location, history, current operations, and geology and hydrogeology; (2) The regulatory requirements relevant to clean closure of the impoundments; (3) The closure procedures; and, (4) The procedures for validation and documentation of clean closure.

  4. Perturbed airway closure (United States)

    Grotberg, James B.; Halpern, David


    The small airways of the lungs are lined with a thin viscous film. A surface-tension driven instability at the air-liquid interface may induce the formation of a liquid bridge blocking airflow if there is sufficient fluid within the film. As a result of the pressures generated within the non-uniform film, the airway wall may also collapse. These instabilities often occur in premature neonates who do not produce sufficient quantities of surfactant. Often, they are placed in ventilators to diminish the risk of airway closure. Two fundamental parameters are the frequency of the ventilation and the tidal volume of the delivered gas. In the current study, we consider the effect of an oscillatory shear stress impinged by the air on a thin film coating a single compliant tube. Nonlinear evolution equations are derived for the film thickness and the wall position. Numerical solutions show that the oscillatory shear stress can saturate the growth of a disturbance at the air-liquid interface. For a given film thickness, there is a critical frequency, dependent on wall parameters, above which closure does not occur when forced by oscillatory shear but will close when unforced.

  5. 40 CFR 265.1102 - Closure and post-closure care. (United States)


    ..., STORAGE, AND DISPOSAL FACILITIES Containment Buildings § 265.1102 Closure and post-closure care. (a) At closure of a containment building, the owner or operator must remove or decontaminate all waste residues... applies. The closure plan, closure activities, cost estimates for closure, and financial responsibility...

  6. Numerical Simulation of Atmospheric Boundary Layer Flow Over Battlefield-scale Complex Terrain: Surface Fluxes From Resolved and Subgrid Scales (United States)


    Grimmond, 2015: Proc. 9th International Conference on Urban Climate , Paris, France. Anderson W, Li Q, Bou-Zeid E, 2014: Proc. of American...represen- tative information is known about the macroscale attributes of these coher- ent motions, we have developed a sim- ple, semi -empirical model to...dust from arid landscapes on the Llano Estacado in west Texas and eastern New Mexico. • Under Review: National Science Foundation, Fluid Dynamics Program

  7. A variational multi-scale method with spectral approximation of the sub-scales: Application to the 1D advection-diffusion equations

    KAUST Repository

    Chacón Rebollo, Tomás


    This paper introduces a variational multi-scale method where the sub-grid scales are computed by spectral approximations. It is based upon an extension of the spectral theorem to non necessarily self-adjoint elliptic operators that have an associated base of eigenfunctions which are orthonormal in weighted L2 spaces. This allows to element-wise calculate the sub-grid scales by means of the associated spectral expansion. We propose a feasible VMS-spectral method by truncation of this spectral expansion to a finite number of modes. We apply this general framework to the convection-diffusion equation, by analytically computing the family of eigenfunctions. We perform a convergence and error analysis. We also present some numerical tests that show the stability of the method for an odd number of spectral modes, and an improvement of accuracy in the large resolved scales, due to the adding of the sub-grid spectral scales.

  8. Closure report for N Reactor

    Energy Technology Data Exchange (ETDEWEB)


    This report has been prepared to satisfy Section 3156(b) of Public Law 101-189 (Reports in Connection with Permanent Closures of Department of Energy Defense Nuclear Facilities), which requires submittal of a Closure Report to Congress by the Secretary of Energy upon the permanent cessation of production operations at a US Department of Energy (DOE) defense nuclear facility (Watkins 1991). This closure report provides: (1) A complete survey of the environmental problems at the facility; (2) Budget quality data indicating the cost of environmental restoration and other remediation and cleanup efforts at the facility; (3) A proposed cleanup schedule.

  9. RCRA closure of mixed waste impoundments

    Energy Technology Data Exchange (ETDEWEB)

    Blaha, F.J. [Doty and Associates (United States); Greengard, T.C.; Arndt, M.B. [Rockwell International (United States)


    A case study of a RCRA closure action at the Rocky Flats Plant is presented. Closure of the solar evaporation ponds involves removal and immobilization of a mixed hazardous/radioactive sludge, treatment of impounded water, groundwater monitoring, plume delineation, and collection and treatment of contaminated groundwater. The site closure is described within the context of regulatory negotiations, project schedules, risk assessment, clean versus dirty closure, cleanup levels, and approval of closure plans and reports. Lessons learned at Rocky Flats are summarized.

  10. Time line cell tracking for the approximation of lagrangian coherent structures with subgrid accuracy

    KAUST Repository

    Kuhn, Alexander


    Lagrangian coherent structures (LCSs) have become a widespread and powerful method to describe dynamic motion patterns in time-dependent flow fields. The standard way to extract LCS is to compute height ridges in the finite-time Lyapunov exponent field. In this work, we present an alternative method to approximate Lagrangian features for 2D unsteady flow fields that achieve subgrid accuracy without additional particle sampling. We obtain this by a geometric reconstruction of the flow map using additional material constraints for the available samples. In comparison to the standard method, this allows for a more accurate global approximation of LCS on sparse grids and for long integration intervals. The proposed algorithm works directly on a set of given particle trajectories and without additional flow map derivatives. We demonstrate its application for a set of computational fluid dynamic examples, as well as trajectories acquired by Lagrangian methods, and discuss its benefits and limitations. © 2013 The Authors Computer Graphics Forum © 2013 The Eurographics Association and John Wiley & Sons Ltd.

  11. Stochastic representation of the Reynolds transport theorem: revisiting large-scale modeling

    CERN Document Server

    Harouna, S Kadri


    We explore the potential of a formulation of the Navier-Stokes equations incorporating a random description of the small-scale velocity component. This model, established from a version of the Reynolds transport theorem adapted to a stochastic representation of the flow, gives rise to a large-scale description of the flow dynamics in which emerges an anisotropic subgrid tensor, reminiscent to the Reynolds stress tensor, together with a drift correction due to an inhomogeneous turbulence. The corresponding subgrid model, which depends on the small scales velocity variance, generalizes the Boussinesq eddy viscosity assumption. However, it is not anymore obtained from an analogy with molecular dissipation but ensues rigorously from the random modeling of the flow. This principle allows us to propose several subgrid models defined directly on the resolved flow component. We assess and compare numerically those models on a standard Green-Taylor vortex flow at Reynolds 1600. The numerical simulations, carried out w...

  12. [Endoscopic vacuum-assisted closure]. (United States)

    Wedemeyer, J; Lankisch, T


    Anastomotic leakage in the upper and lower intestinal tract is associated with high morbidity and mortality. Within the last 10 years endoscopic treatment options have been accepted as sufficient treatment option of these surgical complications. Endoscopic vacuum assisted closure (E-VAC) is a new innovative endoscopic therapeutic option in this field. E-VAC transfers the positive effects of vacuum assisted closure (VAC) on infected cutaneous wounds to infected cavities that can only be reached endoscopically. A sponge connected to a drainage tube is endoscopically placed in the leakage and a continuous vacuum is applied. Sponge and vacuum allow removal of infected fluids and promote granulation of the leakage. This results in clean wound grounds and finally allows wound closure. Meanwhile the method was also successfully used in the treatment of necrotic pancreatitis.

  13. Sub-grid combustion modeling for compressible two-phase reacting flows (United States)

    Sankaran, Vaidyanathan


    A generic formulation for modeling the turbulent combustion in compressible, high Reynolds number, two-phase; reacting flows has been developed and validated. A sub-grid mixing/combustion model called Linear Eddy Mixing (LEM) model has been extended to compressible flows and used inside the framework of Large Eddy Simulation (LES) in this LES-LEM approach. The LES-LEM approach is based on the proposition that the basic mechanistic distinction between the convective and the molecular effects should be preserved for accurate prediction of complex flow-fields such as those encountered in many combustion systems. Liquid droplets (represented by computational parcels) are tracked using the Lagrangian approach wherein the Newton's equation of motion for the discrete particles are integrated explicitly in the Eulerian gas field. The gas phase LES velocity fields are used to estimate the instantaneous gas velocity at the droplet location. Drag effects due to the droplets on the gas phase and the heat transfer between the gas and the liquid phase are explicitly included. Thus, full coupling is achieved between the two phases in the simulation. Validation of the compressible LES-LEM approach is conducted by simulating the flow-field in an operational General Electric Aircraft Engines combustor (LM6000). The results predicted using the proposed approach compares well with the experiments and a conventional (G-equation) thin-flame model. Particle tracking algorithms used in the present study are validated by simulating droplet laden temporal mixing layers. Quantitative and qualitative comparison with the results of spectral DNS exhibits good agreement. Simulations using the current LES-LEM for freely propagating partially premixed flame in a droplet-laden isotropic turbulent field correctly captures the flame structure in the partially premixed flames. Due to the strong spatial variation of equivalence ratio a broad flame similar to a premixed flame is realized. The current

  14. Outcome of colostomy closure with different skin closure techniques ...

    African Journals Online (AJOL)

    Background: Colostomy site, which is a potentially contaminated wound, is traditionally closed with interrupted skin stitches and placement of intraperitoneal or parietal or both drains; often with poor cosmetic outcome in our country. This study aims at prospective evaluation of colostomy closure wounds by different ...

  15. Moment Closure for the Stochastic Logistic Model

    National Research Council Canada - National Science Library

    Singh, Abhyudai; Hespanha, Joao P


    ..., which we refer to as the moment closure function. In this paper, a systematic procedure for constructing moment closure functions of arbitrary order is presented for the stochastic logistic model...

  16. Telephone switchboard closure | 19 December

    CERN Multimedia


    Exceptionally, the telephone switchboard will close at 4 p.m. on Friday, 19 December, instead of the usual time of 6 p.m., to allow time for closing all systems properly before the annual closure. Therefore, switchboard operator assistance to transfer calls from/to external lines will stop. All other phone services will run as usual.

  17. An improvised wound closure system

    NARCIS (Netherlands)

    Lapid, Oren


    BACKGROUND: Skin stretching harnesses the same viscoelastic properties of the skin as expansion, with the difference that the forces are applied externally and not internally. An improvised system for wound closure is presented. METHOD: The system is assembled using silicone vascular loops used as

  18. Vacuum assisted closure in coloproctology

    NARCIS (Netherlands)

    Bemelman, W.A.


    Vacuum-assisted closure has earned its indications in coloproctology. It has been described with variable results in the treatment of large perineal defects after abdominoperineal excision, in the treatment of stoma dehiscence and perirectal abscesses. The most promising indication for

  19. Abdominal wound closure: current perspectives

    Directory of Open Access Journals (Sweden)

    Williams ZF


    Full Text Available Zachary F Williams, William W Hope Department of Surgery, South East Area Health Education Center, New Hanover Regional Medical Center, Wilmington, NC, USA Abstract: This review examines both early and late wound complications following laparotomy closure, with particular emphasis on technical aspects that reduce hernia formation. Abdominal fascial closure is an area of considerable variation within the field of general surgery. The formation of hernias following abdominal wall incisions continues to be a challenging problem. Ventral hernia repairs are among the most common surgeries performed by general surgeons, and despite many technical advances in the field, incisional hernia rates remain high. Much attention and research has been directed to the surgical management of hernias. Less focus has been placed on prevention of hernia formation despite its obvious importance. This review examines the effects of factors such as the type of incision, suture type and size, closure method, patient risk factors, and the use of prophylactic mesh. Keywords: incisional, abdominal, hernia, prevention, wound closure techniques 

  20. Variational Multi-Scale method with spectral approximation of the sub-scales.

    KAUST Repository

    Dia, Ben Mansour


    A variational multi-scale method where the sub-grid scales are computed by spectral approximations is presented. It is based upon an extension of the spectral theorem to non necessarily self-adjoint elliptic operators that have an associated base of eigenfunctions which are orthonormal in weighted L2 spaces. We propose a feasible VMS-spectral method by truncation of this spectral expansion to a nite number of modes.

  1. Distributed Programming via Safe Closure Passing

    Directory of Open Access Journals (Sweden)

    Philipp Haller


    Full Text Available Programming systems incorporating aspects of functional programming, e.g., higher-order functions, are becoming increasingly popular for large-scale distributed programming. New frameworks such as Apache Spark leverage functional techniques to provide high-level, declarative APIs for in-memory data analytics, often outperforming traditional "big data" frameworks like Hadoop MapReduce. However, widely-used programming models remain rather ad-hoc; aspects such as implementation trade-offs, static typing, and semantics are not yet well-understood. We present a new asynchronous programming model that has at its core several principles facilitating functional processing of distributed data. The emphasis of our model is on simplicity, performance, and expressiveness. The primary means of communication is by passing functions (closures to distributed, immutable data. To ensure safe and efficient distribution of closures, our model leverages both syntactic and type-based restrictions. We report on a prototype implementation in Scala. Finally, we present preliminary experimental results evaluating the performance impact of a static, type-based optimization of serialization.

  2. 27 CFR 27.62 - Affixing closures. (United States)


    ... OF THE TREASURY LIQUORS IMPORTATION OF DISTILLED SPIRITS, WINES, AND BEER General Requirements Closures for Containers of Distilled Spirits § 27.62 Affixing closures. Closures or other devices on containers of imported distilled spirits having a capacity of 1 gallon (3.785 liters) or less shall be...

  3. Sensitivity of the scale partition for variational multiscale large-eddy simulation of channel flow

    NARCIS (Netherlands)

    Holmen, J.; Hughes, T.J.R.; Oberai, A.A.; Wells, G.N.


    The variational multiscale method has been shown to perform well for large-eddy simulation (LES) of turbulent flows. The method relies upon a partition of the resolved velocity field into large- and small-scale components. The subgrid model then acts only on the small scales of motion, unlike

  4. From Detailed Description of Chemical Reacting Carbon Particles to Subgrid Models for CFD

    Directory of Open Access Journals (Sweden)

    Schulze S.


    Full Text Available This work is devoted to the development and validation of a sub-model for the partial oxidation of a spherical char particle moving in an air/steam atmosphere. The particle diameter is 2 mm. The coal particle is represented by moisture- and ash-free nonporous carbon while the coal rank is implemented using semi-global reaction rate expressions taken from the literature. The submodel includes six gaseous chemical species (O2, CO2, CO, H2O, H2, N2. Three heterogeneous reactions are employed, along with two homogeneous semi-global reactions, namely carbon monoxide oxidation and the water-gas-shift reaction. The distinguishing feature of the subgrid model is that it takes into account the influence of homogeneous reactions on integral characteristics such as carbon combustion rates and particle temperature. The sub-model was validated by comparing its results with a comprehensive CFD-based model resolving the issues of bulk flow and boundary layer around the particle. In this model, the Navier-Stokes equations coupled with the energy and species conservation equations were used to solve the problem by means of the pseudo-steady state approach. At the surface of the particle, the balance of mass, energy and species concentration was applied including the effect of the Stefan flow and heat loss due to radiation at the surface of the particle. Good agreement was achieved between the sub-model and the CFD-based model. Additionally, the CFD-based model was verified against experimental data published in the literature (Makino et al. (2003 Combust. Flame 132, 743-753. Good agreement was achieved between numerically predicted and experimentally obtained data for input conditions corresponding to the kinetically controlled regime. The maximal discrepancy (10% between the experiments and the numerical results was observed in the diffusion-controlled regime. Finally, we discuss the influence of the Reynolds number, the ambient O2 mass fraction and the ambient

  5. Effects of cumulus parameterization closures on simulations of summer precipitation over the continental United States (United States)

    Qiao, Fengxue; Liang, Xin-Zhong


    This study examines the effects of five cumulus closure assumptions on simulations of summer precipitation in the continental U.S. by utilizing an ensemble cumulus parameterization (ECP) that incorporates multiple alternate closure schemes into a single cloud model formulation. Results demonstrate that closure algorithms significantly affect the summer mean, daily frequency and intensity, and diurnal variation of precipitation, with strong regional dependence. Overall, the vertical velocity (W) closure produces the smallest summer mean biases, while the moisture convergence (MC) closure most realistically reproduces daily variability. Both closures have advantages over others in simulating U.S. daily rainfall frequency distribution, though both slightly overestimate intense rain events. The MC closure is superior at capturing summer rainfall amount, daily variability, and heavy rainfall frequency over the Central U.S., but systematically produces wet biases over the North American Monsoon (NAM) region and Southeast U.S., which can be reduced by using the W closure. The instability tendency (TD) and the total instability adjustment (KF) closures are better at capturing observed diurnal signals over the Central U.S. and the NAM, respectively. The results reasonably explain the systematic behaviors of several major cumulus parameterizations. A preliminary experiment combining two optimal closures (averaged moisture convergence and vertical velocity) in the ECP scheme significantly reduced the wet (dry) biases over the Southeast U.S. in the summer of 1993 (2003), and greatly improved daily rainfall correlations over the NAM. Further improved model simulation skills may be achieved in the future if optimal closures and their appropriate weights can be derived at different time scales based on specific climate regimes.

  6. A scale invariance criterion for LES parametrizations

    Directory of Open Access Journals (Sweden)

    Urs Schaefer-Rolffs


    Full Text Available Turbulent kinetic energy cascades in fluid dynamical systems are usually characterized by scale invariance. However, representations of subgrid scales in large eddy simulations do not necessarily fulfill this constraint. So far, scale invariance has been considered in the context of isotropic, incompressible, and three-dimensional turbulence. In the present paper, the theory is extended to compressible flows that obey the hydrostatic approximation, as well as to corresponding subgrid-scale parametrizations. A criterion is presented to check if the symmetries of the governing equations are correctly translated into the equations used in numerical models. By applying scaling transformations to the model equations, relations between the scaling factors are obtained by demanding that the mathematical structure of the equations does not change.The criterion is validated by recovering the breakdown of scale invariance in the classical Smagorinsky model and confirming scale invariance for the Dynamic Smagorinsky Model. The criterion also shows that the compressible continuity equation is intrinsically scale-invariant. The criterion also proves that a scale-invariant turbulent kinetic energy equation or a scale-invariant equation of motion for a passive tracer is obtained only with a dynamic mixing length. For large-scale atmospheric flows governed by the hydrostatic balance the energy cascade is due to horizontal advection and the vertical length scale exhibits a scaling behaviour that is different from that derived for horizontal length scales.

  7. The timing of ostomy closure in infants with necrotizing enterocolitis: a systematic review. (United States)

    Struijs, Marie-Chantal; Sloots, Cornelius E J; Hop, Wim C J; Tibboel, Dick; Wijnen, Rene M H


    The optimal timing of ostomy closure is a matter of debate. We performed a systematic review of outcomes of early ostomy closure (EC, within 8 weeks) and late ostomy closure (LC, after 8 weeks) in infants with necrotizing enterocolitis. PubMed, EMbase, Web-of-Science, and Cinahl were searched for studies that detailed time to ostomy closure, and time to full enteral nutrition (FEN) or complications after ostomy closure. Patients with Hirschsprung's disease or anorectal malformations were excluded. Analysis was performed using SPSS 17 and RevMan 5. Of 778 retrieved articles, 5 met the inclusion criteria. The median score for study quality was 9 [range 8-14 on a scale of 0 to 32 points (Downs and Black, J Epidemiol Community Health 52:377-384, 1998)]. One study described mean time to FEN: 19.1 days after EC (n = 13) versus 7.2 days after LC (n = 24; P = 0.027). Four studies reported complication rates after ostomy closure, complications occurred in 27% of the EC group versus 23% of the LC group. The combined odds ratio (LC vs. EC) was 1.1 [95% CI 0.5, 2.5]. Evidence that supports early or late closure is scarce and the published articles are of poor quality. There is no significant difference between EC versus LC in the complication rate. This systematic review supports neither early nor late ostomy closure.

  8. Large Eddy Simulation of an SD7003 Airfoil: Effects of Reynolds number and Subgrid-scale modeling

    DEFF Research Database (Denmark)

    Sarlak Chivaee, Hamid


    This paper presents results of a series of numerical simulations in order to study aerodynamic characteristics of the low Reynolds number Selig-Donovan airfoil, SD7003. Large Eddy Simulation (LES) technique is used for all computations at chord-based Reynolds numbers 10,000, 24,000 and 60...

  9. Adaptive moment closure for parameter inference of biochemical reaction networks. (United States)

    Schilling, Christian; Bogomolov, Sergiy; Henzinger, Thomas A; Podelski, Andreas; Ruess, Jakob


    Continuous-time Markov chain (CTMC) models have become a central tool for understanding the dynamics of complex reaction networks and the importance of stochasticity in the underlying biochemical processes. When such models are employed to answer questions in applications, in order to ensure that the model provides a sufficiently accurate representation of the real system, it is of vital importance that the model parameters are inferred from real measured data. This, however, is often a formidable task and all of the existing methods fail in one case or the other, usually because the underlying CTMC model is high-dimensional and computationally difficult to analyze. The parameter inference methods that tend to scale best in the dimension of the CTMC are based on so-called moment closure approximations. However, there exists a large number of different moment closure approximations and it is typically hard to say a priori which of the approximations is the most suitable for the inference procedure. Here, we propose a moment-based parameter inference method that automatically chooses the most appropriate moment closure method. Accordingly, contrary to existing methods, the user is not required to be experienced in moment closure techniques. In addition to that, our method adaptively changes the approximation during the parameter inference to ensure that always the best approximation is used, even in cases where different approximations are best in different regions of the parameter space. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  10. Single clips versus multi-firing clip device for closure of mucosal incisions after peroral endoscopic myotomy (POEM). (United States)

    Verlaan, Tessa; Ponds, Fraukje A M; Bastiaansen, Barbara A J; Bredenoord, Albert J; Fockens, Paul


    Background and aims: After Peroral Endoscopic Myotomy (POEM), the mucosal incision is closed with endoscopically applied clips. After each clip placement, a subsequent clipping device has to be introduced through the working channel. With the Clipmaster3, three consecutive clips can be placed without reloading which could reduce closure time. We performed a prospective study evaluating efficacy, safety, and ease of use. Closure using Clipmaster3 was compared to closure with standard clips. Methods: Patients undergoing closure with the Clipmaster3 were compared to patients who underwent POEM with standard clip closure. Results: In total, 12 consecutive POEM closures with Clipmaster3 were compared to 24 standard POEM procedures. The Clipmaster3 and the standard group did not differ in sex distribution, age (42 years [29 - 49] vs 41 years [34 - 54] P = 0.379), achalasia subtype, disease duration, length of the mucosal incision (25.0 mm [20 - 30] vs 20.0 mm [20 - 30], P = 1.0), and closure time (622 seconds [438 - 909] vs 599 seconds [488 - 664] P = 0.72). Endoscopically successful closure could be performed in all patients. The proportion of all clips used that were either displaced or discarded was larger for Clipmaster3 (8.8 %) compared to standard closure (2.0 %, P  = 0.00782). Ease of handling VAS (visual analogue scale) score for Clipmaster3 did not differ between endoscopist and endoscopy nurse (7 out of 10). Conclusions: Clipmaster3 is feasible and safe for closure of mucosal incisions after POEM. Clipmaster3 was not associated with reduced closure time. Compared to standard closure, more Clipmaster3 clips were displaced or discarded to achieve successful closure. A training effect cannot be excluded as a cause of these results. NCT01405417.

  11. Primary closure of equine laryngotomy incisions

    DEFF Research Database (Denmark)

    Lindegaard, C.; Karlsson, L.; Ekstrøm, Claus Thorn


    The objective was to report healing characteristics and complications after primary closure of equine laryngotomies and analyse factors potentially associated with complications. This retrospective case series of the medical records of horses (n = 180) undergoing laryngoplasty and laryngotomy...... after primary closure of equine laryngotomy incisions are infrequent and considered of minimal severity and can be performed safely when paying careful attention to the closure of the cricothyroid membrane....

  12. Ocular Biometry in Angle Closure

    Directory of Open Access Journals (Sweden)

    Mohammad Reza Razeghinejad


    Full Text Available Purpose: To compare ocular biometric parameters in primary angle closure suspects (PACS, primary angle closure glaucoma (PACG and acute primary angle closure (APAC. Methods: This cross-sectional study was performed on 113 patients including 33 cases of PACS, 45 patients with PACG and 35 subjects with APAC. Central corneal thickness (CCT, axial length (AL, anterior chamber depth (ACD and lens thickness (LT were measured with an ultrasonic biometer. Lens-axial length factor (LAF, relative lens position, corrected ACD (CACD and corrected lens position were calculated. The parameters were measured bilaterally but only data from the right eyes were compared. In the APAC group, biometric parameters were also compared between affected and unaffected fellow eyes. Logistic regression analysis was performed to identify risk factors. Results: No statistically significant difference was observed in biometric parameters between PACS and PACG eyes, or between affected and fellow eyes in the APAC group (P>0.05 for all comparisons. However, eyes with APAC had thicker cornea (P=0.001, thicker lens (P<0.0001, shallower ACD (P=0.009, shallower CACD (P=0.003 and larger LAF (P<0.0001. Based on ROC curve analysis, lower ACD, and larger LT, LAF and CCT values were associated with APAC. In the APAC group, LAF (P<0.0001 and CCT (P=0.001 were significant risk factors. Conclusion: This study revealed no significant difference in biometric characteristics in eyes with PACS and PACG. However, larger LAF and CCT were predictive of APAC.

  13. Sustained eye closure slows saccades (United States)

    Shaikh, Aasef G.; Wong, Aaron L.; Optican, Lance M.; Miura, Kenichiro; Solomon, David; Zee, David S.


    Saccadic eye movements rapidly orient the line of sight towards the object of interest. Pre-motor burst neurons (BNs) controlling saccades receive excitation from superior colliculus and cerebellum, but inhibition by omnipause neurons (OPNs) prevents saccades. When the OPNs pause, BNs begin to fire. It has been presumed that part of the BN burst comes from post-inhibitory rebound (PIR). We hypothesized that in the absence of prior inhibition from OPNs there would be no PIR, and thus the increase in initial firing rate of BNs would be reduced. Consequently, saccade acceleration would be reduced. We measured eye movements and showed that sustained eye closure, which inhibits the activity of OPNs and thus hypothetically should weaken PIR, reduced the peak velocity, acceleration, and deceleration of saccades in healthy human subjects. Saccades under closed eyelids also had irregular trajectories; the frequency of the oscillations underlying this irregularity was similar to that of high-frequency ocular flutter (back-to-back saccades) often seen in normal subjects during attempted fixation at straight ahead while eyes are closed. Saccades and quick phases of nystagmus are generated by the same pre-motor neurons, and we found that the quick-phase velocity of nystagmus was also reduced by lid closure. These changes were not due to a mechanical hindrance to the eyes, because lid closure did not affect the peak velocities or accelerations of the eyes in the “slow-phase” response to rapid head movements of comparable speeds to those of saccades. These results indicate a role for OPNs in generating the abrupt onset and high velocities of saccades. We hypothesize that the mechanism involved is PIR in pre-motor burst neurons. PMID:20573593

  14. A Subgrid Parameterization for Wind Turbines in Weather Prediction Models with an Application to Wind Resource Limits

    Directory of Open Access Journals (Sweden)

    B. H. Fiedler


    Full Text Available A subgrid parameterization is offered for representing wind turbines in weather prediction models. The parameterization models the drag and mixing the turbines cause in the atmosphere, as well as the electrical power production the wind causes in the wind turbines. The documentation of the parameterization is complete; it does not require knowledge of proprietary data of wind turbine characteristics. The parameterization is applied to a study of wind resource limits in a hypothetical giant wind farm. The simulated production density was found not to exceed 1 W m−2, peaking at a deployed capacity density of 5 W m−2 and decreasing slightly as capacity density increased to 20 W m−2.

  15. 100-D Ponds closure plan. Revision 1

    Energy Technology Data Exchange (ETDEWEB)

    Petersen, S.W.


    The 100-D Ponds is a Treatment, Storage, and Disposal (TSD) unit on the Hanford Facility that received both dangerous and nonregulated waste. This Closure Plan (Rev. 1) for the 100-D Ponds TSD unit consists of a RCRA Part A Dangerous Waste Permit Application (Rev. 3), a RCRA Closure Plan, and supporting information contained in the appendices to the plan. The closure plan consists of eight chapters containing facility description, process information, waste characteristics, and groundwater monitoring data. There are also chapters containing the closure strategy and performance standards. The strategy for the closure of the 100-D Ponds TSD unit is clean closure. Appendices A and B of the closure plan demonstrate that soil and groundwater beneath 100-D Ponds are below cleanup limits. All dangerous wastes or dangerous waste constituents or residues associated with the operation of the ponds have been removed, therefore, human health and the environment are protected. Discharges to the 100-D Ponds, which are located in the 100-DR-1 operable unit, were discontinued in June 1994. Contaminated sediment was removed from the ponds in August 1996. Subsequent sampling and analysis demonstrated that there is no contamination remaining in the ponds, therefore, this closure plan is a demonstration of clean closure.

  16. Glottic closure patterns: type I thyroplasty versus type I thyroplasty with arytenoid adduction. (United States)

    Li, Anya J; Johns, Michael M; Jackson-Menaldi, Cristina; Dailey, Seth; Heman-Ackah, Yolanda; Merati, Albert; Rubin, Adam D


    The goal of laryngeal framework surgery in patients with unilateral vocal fold paralysis is to improve glottic closure by medializing the paralyzed vocal fold. Type I thyroplasty (Th) and arytenoid adduction (AA) are two of the most commonly performed procedures. Two of the main rationales for performing an AA are to improve closure of the posterior glottis and correct vertical height discrepancy. The purpose of this study was to evaluate if AA with Th yields better posterior glottic closure and vertical height equality than Th alone. Retrospective. Using visual analog scales, three blinded reviewers evaluated glottic closure patterns in patients who underwent Th or Th with AA. Pre- and postoperative videostroboscopic examinations of 45 patients with unilateral vocal fold paralysis, who underwent laryngeal framework surgery, were evaluated. No significant difference was identified in postoperative scores for midmembranous glottis closure (P=0.282), closure just anterior to the vocal processes (P=0.426), respiratory glottis closure (P=0.158), or vertical height discrepancy (P=0.113). Although larger glottic gaps and vertical height discrepancies may lead some surgeons to predict that an AA is warranted, the usefulness of AA may not always be related to these parameters. Ultimately, voice improvement and not geometry should guide the surgeon's decision making. Copyright © 2011 The Voice Foundation. Published by Mosby, Inc. All rights reserved.

  17. Comparison of Subcuticular Suture Materials in Cesarean Skin Closure

    Directory of Open Access Journals (Sweden)

    Pınar Solmaz Hasdemir


    Full Text Available Aim. Comparison of the rate of wound complications, pain, and patient satisfaction based on used subcuticular suture material. Methods. A total of 250 consecutive women undergoing primary and repeat cesarean section with low transverse incision were prospectively included. The primary outcome was wound complication rate including infection, dehiscence, hematoma, and hypertrophic scar formation within a 6-week period after operation. Secondary outcomes were skin closure time, the need for use of additional analgesic agent, pain score on numeric rating scale, cosmetic score, and patient scar satisfaction scale. Results. Absorbable polyglactin was used in 108 patients and nonabsorbable polypropylene was used in 142 patients. Wound complication rates were similar in primary and repeat cesarean groups based on the type of suture material. Skin closure time is longer in nonabsorbable suture material group in both primary and repeat cesarean groups. There was no difference between groups in terms of postoperative pain, need for additional analgesic use, late phase pain, and itching at the scar. Although the cosmetic results tended to be better in the nonabsorbable group in primary surgery patients, there was no significant difference in the visual satisfaction of the patients. Conclusions. Absorbable and nonabsorbable suture materials are comparable in cesarean section operation skin closure.

  18. 40 CFR 146.71 - Closure. (United States)


    ... Director. (3) Prior to well closure, the well shall be flushed with a buffer fluid. (4) Upon closure, a... of fluids into or between USDWs. (5) Placement of the cement plugs shall be accomplished by one of... is completed. (7) The well to be closed shall be in a state of static equilibrium with the mud weight...

  19. Acute angle closure glaucoma following ileostomy surgery

    Directory of Open Access Journals (Sweden)

    Mariana Meirelles Lopes


    Full Text Available Angle-closure glaucoma can be induced by drugs that may cause pupillary dilatation. We report a case of a patient that developed bilateral angle closure glaucoma after an ileostomy surgery because of systemic atropine injection. This case report highlights the importance of a fast ophthalmologic evaluation in diseases with ocular involvement in order to make accurate diagnoses and appropriate treatments.

  20. Hospital closure: Phoenix, Hydra or Titanic? (United States)

    Dunne, T; Davis, S


    Very little has been published about the effects of hospital closure in terms of the service, financial or management issues of the process. Attempts through a case-study format to redress the balance and as such represents the reflections of practitioners who have recently undergone the experience of hospital closure and the often neglected issues arising both during and after the process.

  1. Complementary techniques of percutaneous closure of ductus ...

    African Journals Online (AJOL)

    East African Medical Journal ... Device closure of the ductus was first performed at the Mater hospital in 1999 in a ten year old male using a five millilitre detachable cook coil. In 2000 the ... We report this single centre experience of percutaneous PDA closure in a resource-limited setting; utilising the two techniques.

  2. Hortonian runoff closure relations for geomorphologic response units: evaluation against field data

    NARCIS (Netherlands)

    Vannametee, E.|info:eu-repo/dai/nl/341156515; Karssenberg, D.J.|info:eu-repo/dai/nl/241557119; Hendriks, M.R.|info:eu-repo/dai/nl/075179504; Bierkens, M.F.P.|info:eu-repo/dai/nl/125022794


    This paper presents an evaluation of the closure relation for Hortonian runoff, proposed in Vannametee et al. (2012), that incorporates a scaling component to explicitly account for the process heterogeneity and scale effects in runoff generation for the real-world case studies. We applied the

  3. Vacuum-Assisted Closure for Episiotomy Dehiscence. (United States)

    Aviki, Emeline M; Batalden, Rebecca Posthuma; del Carmen, Marcela G; Berkowitz, Lori R


    Episiotomy dehiscence can result in a large vulvovaginal defect not amenable to delayed primary closure. A 26-year-old woman who underwent a forceps-assisted vaginal delivery with mediolateral episiotomy presented on postpartum day 5 with complete wound breakdown. Surgical exploration of the wound revealed a defect extending from the perineum into the vagina and deep into the ischiorectal fossa with poor tissue quality not amenable to a timely delayed primary closure. A vacuum-assisted closure device was used in lieu of traditional wound preparation and resulted in wound closure after 11 days of vacuum-assisted wound therapy. A vacuum-assisted closure device may be appropriate in cases of complex episiotomy breakdown and may expedite wound healing in the outpatient setting.

  4. Intermittent acute angle closure glaucoma and chronic angle closure following topiramate use with plateau iris configuration

    Directory of Open Access Journals (Sweden)

    Rajjoub LZ


    Full Text Available Lamise Z Rajjoub, Nisha Chadha, David A Belyea Department of Ophthalmology, The George Washington University, Washington, DC, USA Abstract: This is a case report describing recurrent intermittent acute angle closure episodes in the setting of topiramate use in a female suffering from migraines. Despite laser peripheral iridotomy placement for the pupillary block component, and the discontinuation of topiramate, the acute angle closure did not resolve in the left eye with chronic angle closure and the patient required urgent trabeculectomy. The right eye responded to laser peripheral iridotomy immediately and further improved after the cessation of topiramate. While secondary angle closure glaucoma due to topiramate use has been widely reported, its effects in patients with underlying primary angle closure glaucoma have not been discussed. Our report highlights the importance of recognizing the often multifactorial etiology of angle closure glaucoma to help guide clinical management. Keywords: angle closure glaucoma, plateau iris, topiramate, secondary glaucoma, drug-induced glaucoma

  5. Simulation of subgrid orographic precipitation with an embedded 2-D cloud-resolving model (United States)

    Jung, Joon-Hee; Arakawa, Akio


    By explicitly resolving cloud-scale processes with embedded two-dimensional (2-D) cloud-resolving models (CRMs), superparameterized global atmospheric models have successfully simulated various atmospheric events over a wide range of time scales. Up to now, however, such models have not included the effects of topography on the CRM grid scale. We have used both 3-D and 2-D CRMs to simulate the effects of topography with prescribed "large-scale" winds. The 3-D CRM is used as a benchmark. The results show that the mean precipitation can be simulated reasonably well by using a 2-D representation of topography as long as the statistics of the topography such as the mean and standard deviation are closely represented. It is also shown that the use of a set of two perpendicular 2-D grids can significantly reduce the error due to a 2-D representation of topography.

  6. Climate Simulations from Super-parameterized and Conventional General Circulation Models with a Third-order Turbulence Closure (United States)

    Xu, Kuan-Man; Cheng, Anning


    A high-resolution cloud-resolving model (CRM) embedded in a general circulation model (GCM) is an attractive alternative for climate modeling because it replaces all traditional cloud parameterizations and explicitly simulates cloud physical processes in each grid column of the GCM. Such an approach is called "Multiscale Modeling Framework." MMF still needs to parameterize the subgrid-scale (SGS) processes associated with clouds and large turbulent eddies because circulations associated with planetary boundary layer (PBL) and in-cloud turbulence are unresolved by CRMs with horizontal grid sizes on the order of a few kilometers. A third-order turbulence closure (IPHOC) has been implemented in the CRM component of the super-parameterized Community Atmosphere Model (SPCAM). IPHOC is used to predict (or diagnose) fractional cloudiness and the variability of temperature and water vapor at scales that are not resolved on the CRM's grid. This model has produced promised results, especially for low-level cloud climatology, seasonal variations and diurnal variations (Cheng and Xu 2011, 2013a, b; Xu and Cheng 2013a, b). Because of the enormous computational cost of SPCAM-IPHOC, which is 400 times of a conventional CAM, we decided to bypass the CRM and implement the IPHOC directly to CAM version 5 (CAM5). IPHOC replaces the PBL/stratocumulus, shallow convection, and cloud macrophysics parameterizations in CAM5. Since there are large discrepancies in the spatial and temporal scales between CRM and CAM5, IPHOC used in CAM5 has to be modified from that used in SPCAM. In particular, we diagnose all second- and third-order moments except for the fluxes. These prognostic and diagnostic moments are used to select a double-Gaussian probability density function to describe the SGS variability. We also incorporate a diagnostic PBL height parameterization to represent the strong inversion above PBL. The goal of this study is to compare the simulation of the climatology from these three

  7. Closure of Microcosm for refurbishment

    CERN Multimedia


    Since 1994, the Microcosm exhibition has given the opportunity to visitors of all ages and backgrounds to have a first glimpse into the secrets of physics.   To ensure that Microcosm can continue fulfilling its educational aims at the same level of quality for many years to come, it is closing for renovation work on 8 December 2014 and is expected to reopen during Summer 2015. During the closure, the “Fun with Physics” workshop will not take place, but the Universe of Particles exhibition in the Globe and the Passport to the Big Bang circuit will remain accessible to the public, free of charge and with no need to book in advance.  Guided tours of CERN are also available (advance booking required via this page).

  8. An investigation of the sub-grid variability of trace gases and aerosols for global climate modeling

    Directory of Open Access Journals (Sweden)

    Y. Qian


    Full Text Available One fundamental property and limitation of grid based models is their inability to identify spatial details smaller than the grid cell size. While decades of work have gone into developing sub-grid treatments for clouds and land surface processes in climate models, the quantitative understanding of sub-grid processes and variability for aerosols and their precursors is much poorer. In this study, WRF-Chem is used to simulate the trace gases and aerosols over central Mexico during the 2006 MILAGRO field campaign, with multiple spatial resolutions and emission/terrain scenarios. Our analysis focuses on quantifying the sub-grid variability (SGV of trace gases and aerosols within a typical global climate model grid cell, i.e. 75×75 km2.

    Our results suggest that a simulation with 3-km horizontal grid spacing adequately reproduces the overall transport and mixing of trace gases and aerosols downwind of Mexico City, while 75-km horizontal grid spacing is insufficient to represent local emission and terrain-induced flows along the mountain ridge, subsequently affecting the transport and mixing of plumes from nearby sources. Therefore, the coarse model grid cell average may not correctly represent aerosol properties measured over polluted areas. Probability density functions (PDFs for trace gases and aerosols show that secondary trace gases and aerosols, such as O3, sulfate, ammonium, and nitrate, are more likely to have a relatively uniform probability distribution (i.e. smaller SGV over a narrow range of concentration values. Mostly inert and long-lived trace gases and aerosols, such as CO and BC, are more likely to have broad and skewed distributions (i.e. larger SGV over polluted regions. Over remote areas, all trace gases and aerosols are more uniformly distributed compared to polluted areas. Both CO and O3 SGV vertical profiles are nearly constant within the PBL during daytime, indicating that trace gases

  9. Renormalization-group theory for the eddy viscosity in subgrid modeling (United States)

    Zhou, YE; Vahala, George; Hossain, Murshed


    Renormalization-group theory is applied to incompressible three-dimensional Navier-Stokes turbulence so as to eliminate unresolvable small scales. The renormalized Navier-Stokes equation now includes a triple nonlinearity with the eddy viscosity exhibiting a mild cusp behavior, in qualitative agreement with the test-field model results of Kraichnan. For the cusp behavior to arise, not only is the triple nonlinearity necessary but the effects of pressure must be incorporated in the triple term. The renormalized eddy viscosity will not exhibit a cusp behavior if it is assumed that a spectral gap exists between the large and small scales.

  10. Turbulence Closure for Mixing Length Theories (United States)

    Jermyn, Adam S.; Lesaffre, Pierre; Tout, Christopher A.; Chitre, Shashikumar M.


    We present an approach to turbulence closure based on mixing length theory with three-dimensional fluctuations against a two-dimensional background. This model is intended to be rapidly computable for implementation in stellar evolution software and to capture a wide range of relevant phenomena with just a single free parameter, namely the mixing length. We incorporate magnetic, rotational, baroclinic and buoyancy effects exactly within the formalism of linear growth theories with nonlinear decay. We treat differential rotation effects perturbatively in the corotating frame using a novel controlled approximation which matches the time evolution of the reference frame to arbitrary order. We then implement this model in an efficient open source code and discuss the resulting turbulent stresses and transport coefficients. We demonstrate that this model exhibits convective, baroclinic and shear instabilities as well as the magnetorotational instability (MRI). It also exhibits non-linear saturation behaviour, and we use this to extract the asymptotic scaling of various transport coefficients in physically interesting limits.

  11. Sensitivity of the scale partition for variational multiscale large-eddy simulation of channel flow


    Holmen, J; Hughes, T.J.R; Oberai, A.A.; Wells, G. N.


    The variational multiscale method has been shown to perform well for large-eddy simulation (LES) of turbulent flows. The method relies upon a partition of the resolved velocity field into large- and small-scale components. The subgrid model then acts only on the small scales of motion, unlike conventional LES models which act on all scales of motion. For homogeneous isotropic turbulence and turbulent channel flows, the multiscale model can outperform conventional LES formulations. An issue in...


    Atmospheric processes and the associated transport and dispersion of atmospheric pollutants are known to be highly variable in time and space. Current air quality models that characterize atmospheric chemistry effects, e.g. the Community Multi-scale Air Quality (CMAQ), provide vo...

  13. A New Approach to Validate Subgrid Models in Complex High Reynolds Number Flows (United States)


    data are also shown. These figures show the characteristic decrease in correla- tion when the grid is coarsened with the scale similarity model showing...passmms sogbe .iului by a Pus* dll- apWaishmalm ass" immp to bpssm do af sepia abdas h bell pufai aftg a pmiuayomd NO P) emd a smA amedidg of do @*M

  14. A Sheaf Model of the Algebraic Closure

    Directory of Open Access Journals (Sweden)

    Bassel Mannaa


    Full Text Available In constructive algebra one cannot in general decide the irreducibility of a polynomial over a field K. This poses some problems to showing the existence of the algebraic closure of K. We give a possible constructive interpretation of the existence of the algebraic closure of a field in characteristic 0 by building, in a constructive metatheory, a suitable site model where there is such an algebraic closure. One can then extract computational content from this model. We give examples of computation based on this model.

  15. Physics and dynamics coupling across scales in the next generation CESM: Meeting the challenge of high resolution. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Larson, Vincent E.


    This is a final report for a SciDAC grant supported by BER. The project implemented a novel technique for coupling small-scale dynamics and microphysics into a community climate model. The technique uses subcolumns that are sampled in Monte Carlo fashion from a distribution of subgrid variability. The resulting global simulations show several improvements over the status quo.

  16. Numerical Methods for the Optimization of Nonlinear Residual-Based Sungrid-Scale Models Using the Variational Germano Identity

    NARCIS (Netherlands)

    Maher, G.D.; Hulshoff, S.J.


    The Variational Germano Identity [1, 2] is used to optimize the coefficients of residual-based subgrid-scale models that arise from the application of a Variational Multiscale Method [3, 4]. It is demonstrated that numerical iterative methods can be used to solve the Germano relations to obtain

  17. Model Validation for Propulsion - On the TFNS and LES Subgrid Models for a Bluff Body Stabilized Flame (United States)

    Wey, Thomas


    With advances in computational power and availability of distributed computers, the use of even the most complex of turbulent chemical interaction models in combustors and coupled analysis of combustors and turbines is now possible and more and more affordable for realistic geometries. Recent more stringent emission standards have enticed the development of more fuel-efficient and low-emission combustion system for aircraft gas turbine applications. It is known that the NOx emissions tend to increase dramatically with increasing flame temperature. It is well known that the major difficulty, when modeling the turbulence-chemistry interaction, lies in the high non-linearity of the reaction rate expressed in terms of the temperature and species mass fractions. The transport filtered density function (FDF) model and the linear eddy model (LEM), which both use local instantaneous values of the temperature and mass fractions, have been shown to often provide more accurate results of turbulent combustion. In the present, the time-filtered Navier-Stokes (TFNS) approach capable of capturing unsteady flow structures important for turbulent mixing in the combustion chamber and two different subgrid models, LEM-like and EUPDF-like, capable of emulating the major processes occurring in the turbulence-chemistry interaction will be used to perform reacting flow simulations of a selected test case. The selected test case from the Volvo Validation Rig was documented by Sjunnesson.

  18. Extender for securing a closure (United States)

    Thomas, II, Patrick A.


    An apparatus for securing a closure such as door or a window that opens and closes by movement relative to a fixed structure such as a wall or a floor. Many embodiments provide a device for relocating a padlock from its normal location where it secures a fastener (such as a hasp) to a location for the padlock that is more accessible for locking and unlocking the padlock. Typically an extender is provided, where the extender has a hook at a first end that is disposed through the eye of the staple of the hasp, and at an opposing second end the extender has an annulus, such as a hole in the extender or a loop or ring affixed to the extender. The shackle of the padlock may be disposed through the annulus and may be disposed through the eye of a second staple to secure the door or window in a closed or open position. Some embodiments employ a rigid sheath to enclose at least a portion of the extender. Typically the rigid sheath has an open state where the hook is exposed outside the sheath and a closed state where the hook is disposed within the sheath.

  19. complementary techniques of percutaneous closure of ductus ...

    African Journals Online (AJOL)


    Jul 7, 2013 ... We report this single centre experience of percutaneous. PDA closure in a ... Design: A descriptive retrospective cohort study. ... Three of the subjects in the coil group had the ducts embolised using the double technique while ...

  20. Cyanoacrylate for Intraoral Wound Closure: A Possibility?

    Directory of Open Access Journals (Sweden)

    Parimala Sagar


    Full Text Available Wound closure is a part of any surgical procedure and the objective of laceration repair or incision closure is to approximate the edges of a wound so that natural healing process may occur. Over the years new biomaterials have been discovered as an alternate to conventional suture materials. Cyanoacrylate bioadhesives are one among them. They carry the advantages of rapid application, patient comfort, resistance to infection, hemostatic properties, and no suture removal anxiety. Hence this study was undertaken to study the effect of long chain cyanoacrylate as an adhesive for intraoral wound closure and also to explore its hemostatic and antibacterial effects. Isoamyl-2-cyanoacrylate (AMCRYLATE was used as the adhesive in the study. In conclusion isoamyl cyanoacrylate can be used for intraoral wound closure, as an alternative to sutures for gluing the mucoperiosteum to bone, for example, after impaction removal, periapical surgeries, and cleft repair. Its hemostatic and antibacterial activity has to be further evaluated.

  1. Feasibility of lane closures using probe data. (United States)


    To develop an adequate traffic operations management and congestion mitigation plan for every roadway : maintenance and construction project requiring lane closures, transportation agencies need accurate and : reliable estimates of traffic impacts as...

  2. Options for Closure of the Infected Abdomen (United States)

    Campbell, Chris A.; Rosenberger, Laura H.; Politano, Amani D.; Davies, Stephen W.; Riccio, Lin M.; Sawyer, Robert G.


    Abstract Background The infected abdomen poses substantial challenges to surgeons, and often, both temporary and definitive closure techniques are required. We reviewed the options available to close the abdominal wall defect encountered frequently during and after the management of complicated intra-abdominal infections. Methods A comprehensive review was performed of the techniques and literature on abdominal closure in the setting of intra-abdominal infection. Results Temporary abdominal closure options include the Wittmann Patch, Bogota bag, vacuum-assisted closure (VAC), the AbThera™ device, and synthetic or biologic mesh. Definitive reconstruction has been described with mesh, components separation, and autologous tissue transfer. Conclusion Reconstructing the infected abdomen, both temporarily and definitively, can be accomplished with various techniques, each of which is associated with unique advantages and disadvantages. Appropriate judgment is required to optimize surgical outcomes in these complex cases. PMID:23216525

  3. Uterine incision cloSure at caesarean section: A randomised ...

    African Journals Online (AJOL)

    nylon suture size 0. The only difference between the two groups was on the method of closure of uterine incision i.e. intraperitoneal closure or closure after temporary exteriorisation. Intraperitoneal closure. After delivery of the baby and the placenta, the uterine incision is closed with the uterus within the abdominal cavity.

  4. Single-site neural tube closure in human embryos revisited

    NARCIS (Netherlands)

    de Bakker, Bernadette S.; Driessen, Stan; Boukens, Bastiaan J. D.; van den Hoff, Maurice J. H.; Oostra, Roelof-Jan


    Since the multi-site closure theory was first proposed in 1991 as explanation for the preferential localizations of neural tube defects, the closure of the neural tube has been debated. Although the multi-site closure theory is much cited in clinical literature, single-site closure is most apparent

  5. Spontaneous closure of muscular ventricular septal defects

    Directory of Open Access Journals (Sweden)

    Pejčić Ljiljana


    Full Text Available Introduction/Objective. Ventricular septal defect (VSD is the most frequently diagnosed congenital heart anomaly. The prognosis is usually good as it has spontaneous closure evolution, especially small muscular VSDs. The aim of this study was to determine the natural history of isolated muscular VSDs including the frequency of spontaneous closure in relation to location in the muscular septum and the age at the time of closure. Methods. The study included 96 children (52 girls and 44 boys with isolated muscular VSD diagnosed during the first month of life. We analyzed the tendency of spontaneous closure of these defects for the duration of childhood during a follow-up period of 16 years. Two-dimensional color Doppler echocardiography was performed to detect muscular VSD as a primary cardiac lesion. There was significant prevalence of small apical versus trabecular defects and their outcomes were evaluated. Results. Our study evaluated 91 children, 49 (53.8% girls and 42 (46.2% boys who did not undergo surgery. Apically located VSD was diagnosed in 68 (74.7%, while trabecular defects were found in 23 (25.3% children. Spontaneous closure occurred in 56 out of 91 cases (61.5%. The time of spontaneous closure was most commonly recorded during the first six months after birth (46.4%. The overall rate of spontaneous closure was 81.3% by the end of the first year. Apically located ventricular defects underwent spontaneous closure in the majority of patients, in comparison to trabecular ventricular defects (χ2 = 12.581; p < 0.001. Kaplan–Meier analysis demonstrated a significant difference in the average time required for spontaneous closure between the analyzed patient groups (log-rank = 9.64, p = 0.002. Conclusion. The frequency of spontaneous closure of muscular VSDs, especially apically located, is very high in the first six months, especially within the first year of life. It is advisable to detect them early on using color flow imaging and to

  6. Residual Angle Closure One Year After Laser Peripheral Iridotomy in Primary Angle Closure Suspects. (United States)

    Baskaran, Mani; Yang, Elizabeth; Trikha, Sameer; Kumar, Rajesh S; Wong, Hon Tym; He, Mingguang; Chew, Paul T K; Foster, Paul J; Friedman, David; Aung, Tin


    To determine the incidence and baseline clinical and anterior segment optical coherence tomography (AS-OCT) predictors associated with residual angle closure as assessed by gonioscopy 1 year after laser peripheral iridotomy (LPI) in primary angle closure suspects (PACS). Subanalysis of randomized controlled trial data. AS-OCT images from 181 PACS subjects ≥50 years of age were analyzed using customized software before and 1 year after LPI. Other parameters assessed were intraocular pressure (IOP) and axial length (Axl). Residual angle closure was defined as the inability to see the posterior trabecular meshwork for at least 2 quadrants on gonioscopy after LPI. Multivariate regression analysis determined the baseline predictors of residual angle closure 1 year after LPI. The mean age of participants was 62.4 (standard deviation 9.9) years. The majority were female (137, 75.7%) and Chinese (174, 96.1%). At 1 year post LPI, 148 (81.8%) subjects had gonioscopic residual angle closure. Univariate analysis showed that baseline Axl, anterior chamber area, anterior chamber volume, angle opening distance at 750 μm from the scleral spur, and angle recess area were smaller while baseline lens vault and iris curvature were larger in residual angle closure subjects (all P angle closure. One year after LPI, >80% of PACS had gonioscopic residual angle closure. Greater baseline iris volume and higher IOP at baseline are independent risk factors for residual gonioscopic angle closure. Copyright © 2017 Elsevier Inc. All rights reserved.

  7. Why does acute primary angle closure happen? Potential risk factors for acute primary angle closure. (United States)

    Zhang, Xiulan; Liu, Yaoming; Wang, Wei; Chen, Shida; Li, Fei; Huang, Wenbin; Aung, Tin; Wang, Ningli

    Acute primary angle closure is an ocular emergency and requires immediate management to avoid blindness. Narrow anterior chamber angle, advanced age, female gender, and Asian ethnic background are considered risk factors for acute primary angle closure. The predictive power of these factors is, however, relatively poor, and many questions remain unanswered because acute primary angle closure eventually develops in only a relatively small proportion of anatomically predisposed eyes. We summarize the potential roles of various factors in the pathogenesis of acute primary angle closure. Copyright © 2017 Elsevier Inc. All rights reserved.

  8. [Percutaneous closure of patent ductus arteriosus: results and costs compared to surgical closure]. (United States)

    Vieu, T; Beaurain, S; Angel, C; Leriche, H; Petit, J; Conso, J F; Planché, C; Losay, J


    The comparison of the clinical results and costs of the two methods of closure of patient ductus arteriosus was undertaken in two comparable groups of 40 patients treated in the same period in the same hospital. After transcatheter closure there was a 9% residual shunt rate at 3 years, the 2 patients with a residual continuous murmur being operated secondarily. The only complication was severe haemolysis which regressed after transcatheter ablation of the prosthesis. After surgical closure, there were no residual shunt. Some postoperative complications were observed in 20% of cases, usually benign (ventilatory problems, dysphonia or urinary infection), but occasionally more serious (peroperative lesion of the pulmonary artery). Morbidity, inherent to the technique of closure, was very different and much less in catheter closure. The average cost (daily cost x average length of hospital stay) was much less with transcatheter closure 38,558 francs versus 11,240 francs. On the other hand, the direct cost of transcatheter closure was greater than that of surgery: 32,798 francs versus 20,903 francs, the difference being related to the actual price of the prosthesis. The authors conclude that the 3 year results of transcatheter closure of patent ductus arterious make this technique a reasonable therapeutic alternative to surgery. From the safety point of view, the two techniques are comparable bu patient confort is greater with transcatheter closure for an increase in cost of the initial procedure which should decrease in relation to the types and prices of the prosthesis used.

  9. Exceptional closure of UNIQA office at CERN

    CERN Multimedia

    HR Department


    The UNIQA office at CERN will be closed from Wednesday 18 February to Friday 20 February due to painting work. During this closure, the Headquarters of UNIQA in Geneva will remain at the disposal of the members. See details The CERN office will re-open on Monday 23 February according to the normal schedule. We apologise for any inconvenience caused by this closure.

  10. Theater gateway closure: a strategic level barricade (United States)

    logistical planners at the strategic level can anticipate or mitigate the effects of a theater gateway closure on military operations. Through two...the national elements of power was used to find the strategic level effects of the anomaly, that is an unexpected theater gateway closure. It was found...operations. A detailed analysis of the theater gateways location is critical to mitigate or anticipate the sustainment impacts on military operations

  11. Numerical Determination of Crack Opening and Closure Stress Intensity Factors

    DEFF Research Database (Denmark)

    Ricardo, Luiz Carlos Hernandes


    The present work shows the numerical determination of fatigue crack opening and closure stress intensity factors of a C(T) specimen under variable amplitude loading using a finite element method. A half compact tension C(T) specimen, assuming plane stress constraint was used by finite element...... method covering the effects in two-dimensional (2D) small scale yielding models of fatigue crack growth under modified wind turbine standard spectrum loading WISPER. The crack propagation of the finite element model was based on release nodes in the minimum loads to minimize convergence problems...

  12. Why PUB needs scaling (United States)

    Lovejoy, S.; Schertzer, D.; Hubert, P.; Mouchel, J. M.; Benjoudhi, H.; Tchigurinskaya, Y.; Gaume, E.; Vesseire, J.-M.


    Hydrological fields display an extreme variability over a wide range of space-time scales. This variability is beyond the scope of classical mathematical and modeling methods which are forced to combine homogeneity assumptions with scale truncations and subgrid parameterizations. These ad hoc procedures nevertheless lead to complex numerical codes: they are difficult to transfer from one basin to another one, or even to verify with data at a different scale. Tuning the model parameters is hazardous: “predictions” are often reduced to fitting existing observations and are in any case essentially limited to the narrow range of space-time scales over which the parameters have been estimated. In contrast, in recent scaling approaches heterogeneity and uncertainty at all scales are no longer obstacles. The variability is viewed as a consequence of a scale symmetry which must first be elucidated and then exploited: small scale homogeneity assumptions are replaced by small scale heterogeneity assumptions which are verified from data covering wide ranges of scale. PUB provides an unprecedented opportunity not only to test scaling concepts and techniques, but also to development them further. Indeed, PUB can be restated in the following manner: given a partial knowledge on the input (atmospheric states, dynamics and fluxes) and of the media (basin) over a given range of scales, what can we predict for the output (steamflow and water quality) and over which range of scales? We illustrate this state of the art with examples taken from various projects involving precipitation and stream flow collectively spanning the range of scales from centimeters to planetary scales in space, from seconds to tens of years in time.

  13. 77 FR 75186 - Notice of Closure, Target Shooting Public Safety Closure on the Lake Mountains in Utah County, UT (United States)


    ... Bureau of Land Management Notice of Closure, Target Shooting Public Safety Closure on the Lake Mountains... shooting to protect public safety. This closure does not restrict other public activities or access to the Lake Mountains area. DATES: This target shooting closure within the described area will remain in...

  14. Accelerating cleanup: Paths to closure

    Energy Technology Data Exchange (ETDEWEB)



    This report describes the status of Environmental Management`s (EM`s) cleanup program and a direction forward to complete achievement of the 2006 vision. Achieving the 2006 vision results in significant benefits related to accomplishing EM program objectives. As DOE sites accelerate cleanup activities, risks to public health, the environment, and worker safety and health are all reduced. Finding more efficient ways to conduct work can result in making compliance with applicable environmental requirements easier to achieve. Finally, as cleanup activities at sites are completed, the EM program can focus attention and resources on the small number of sites with more complex cleanup challenges. Chapter 1 describes the process by which this report has been developed and what it hopes to accomplish, its relationship to the EM decision-making process, and a general background of the EM mission and program. Chapter 2 describes how the site-by-site projections were constructed, and summarizes, for each of DOE`s 11 Operations/Field Offices, the projected costs and schedules for completing the cleanup mission. Chapter 3 presents summaries of the detailed cleanup projections from three of the 11 Operations/Field Offices: Rocky Flats (Colorado), Richland (Washington), and Savannah River (South Carolina). The remaining eight Operations/Field Office summaries are in Appendix E. Chapter 4 reviews the cost drivers, budgetary constraints, and performance enhancements underlying the detailed analysis of the 353 projects that comprise EM`s accelerated cleanup and closure effort. Chapter 5 describes a management system to support the EM program. Chapter 6 provides responses to the general comments received on the February draft of this document.

  15. Land use-based landscape planning and restoration in mine closure areas. (United States)

    Zhang, Jianjun; Fu, Meichen; Hassani, Ferri P; Zeng, Hui; Geng, Yuhuan; Bai, Zhongke


    Landscape planning and restoration in mine closure areas is not only an inevitable choice to sustain mining areas but also an important path to maximize landscape resources and to improve ecological function in mine closure areas. The analysis of the present mine development shows that many mines are unavoidably facing closures in China. This paper analyzes the periodic impact of mining activities on landscapes and then proposes planning concepts and principles. According to the landscape characteristics in mine closure areas, this paper classifies available landscape resources in mine closure areas into the landscape for restoration, for limited restoration and for protection, and then summarizes directions for their uses. This paper establishes the framework of spatial control planning and design of landscape elements from "macro control, medium allocation and micro optimization" for the purpose of managing and using this kind of special landscape resources. Finally, this paper applies the theories and methods to a case study in Wu'an from two aspects: the construction of a sustainable land-use pattern on a large scale and the optimized allocation of typical mine landscape resources on a small scale.

  16. Anterior Segment Imaging for Angle Closure. (United States)

    Chansangpetch, Sunee; Rojanapongpun, Prin; Lin, Shan C


    To summarize the role of anterior segment imaging (AS-imaging) in angle closure diagnosis and management, and the possible advantages over the current standard of gonioscopy. Literature review and perspective. Review of the pertinent publications with interpretation and perspective in relation to the use of AS-imaging in angle closure assessment focusing on anterior segment optical coherence tomography and ultrasound biomicroscopy. Several limitations have been encountered with the reference standard of gonioscopy for angle assessment. AS-imaging has been shown to have performance in angle closure detection compared to gonioscopy. Also, imaging has greater reproducibility and serves as better documentation for long-term follow-up than conventional gonioscopy. The qualitative and quantitative information obtained from AS-imaging enables better understanding of the underlying mechanisms of angle closure and provides useful parameters for risk assessment and possible prediction of the response to laser and surgical intervention. The latest technologies-including 3-dimensional imaging-have allowed for the assessment of the angle that simulates the gonioscopic view. These advantages suggest that AS-imaging has a potential to be a reference standard for the diagnosis and monitoring of angle closure disease in the future. Although gonioscopy remains the primary method of angle assessment, AS-imaging has an increasing role in angle closure screening and management. The test should be integrated into clinical practice as an adjunctive tool for angle assessment. It is arguable that AS-imaging should be considered first-line screening for patients at risk for angle closure. Copyright © 2018 Elsevier Inc. All rights reserved.

  17. Vendor Assessment for the Waste Package Closure System (Yucca Mtn. Project)

    Energy Technology Data Exchange (ETDEWEB)

    Colleen Shelton-Davis


    The Idaho National Engineering and Environmental Laboratory (INEEL) has been tasked with developing, designing, constructing, and operating a full-scale prototype of the work package closure system. As a precursor to developing the conceptual design, all commercially available equipment was assessed to identify any existing technology gaps. This report presents the results of that assessment for all major equipment.

  18. Vendor Assessment for the Waste Package Closure System (Yucca Mountain Project)

    Energy Technology Data Exchange (ETDEWEB)

    Shelton-Davis, C.V.


    The Idaho National Engineering and Environmental Laboratory (INEEL) has been tasked with developing, designing, constructing, and operating a full-scale prototype of the work package closure system. As a precursor to developing the conceptual design, all commercially available equipment was assessed to identify any existing technology gaps. This report presents the results of that assessment for all major equipment.

  19. Consistent Two-Equation Closure Modelling for Atmospheric Research: Buoyancy and Vegetation Implementations

    DEFF Research Database (Denmark)

    Sogachev, Andrey; Kelly, Mark C.; Leclerc, Monique Y.


    A self-consistent two-equation closure treating buoyancy and plant drag effects has been developed, through consideration of the behaviour of the supplementary equation for the length-scale-determining variable in homogeneous turbulent flow. Being consistent with the canonical flow regimes of gri...

  20. Energy budget closure observed in paired Eddy Covariance towers with increased and continuous daily turbulence (United States)

    The lack of energy closure has been a longstanding issue with Eddy Covariance (EC). Multiple mechanisms have been proposed to explain the discrepancies in energy balance including diurnal energy storage changes, advection of energy, and larger scale turbulent processes that cannot be resolved by fi...

  1. A Note on Two-Equation Closure Modelling of Canopy Flow

    DEFF Research Database (Denmark)

    Sogachev, Andrey


    The note presents a rational approach to modelling the source/sink due to vegetation or buoyancy effects that appear in the turbulent kinetic energy, E, equation and a supplementary equation for a length-scale determining variable, φ, when two-equation closure is applied to canopy and atmospheric...

  2. Large scale finite element solvers for the large eddy simulation of incompressible turbulent flows


    Colomés Gené, Oriol


    In this thesis we have developed a path towards large scale Finite Element simulations of turbulent incompressible flows. We have assessed the performance of residual-based variational multiscale (VMS) methods for the large eddy simulation (LES) of turbulent incompressible flows. We consider VMS models obtained by different subgrid scale approximations which include either static or dynamic subscales, linear or nonlinear multiscale splitting, and different choices of the subscale space. W...

  3. Space Station evolution study oxygen loop closure (United States)

    Wood, M. G.; Delong, D.


    In the current Space Station Freedom (SSF) Permanently Manned Configuration (PMC), physical scars for closing the oxygen loop by the addition of oxygen generation and carbon dioxide reduction hardware are not included. During station restructuring, the capability for oxygen loop closure was deferred to the B-modules. As such, the ability to close the oxygen loop in the U.S. Laboratory module (LAB A) and the Habitation A module (HAB A) is contingent on the presence of the B modules. To base oxygen loop closure of SSF on the funding of the B-modules may not be desirable. Therefore, this study was requested to evaluate the necessary hooks and scars in the A-modules to facilitate closure of the oxygen loop at or subsequent to PMC. The study defines the scars for oxygen loop closure with impacts to cost, weight and volume and assesses the effects of byproduct venting. In addition, the recommended scenarios for closure with regard to topology and packaging are presented.

  4. Attempted eyelid closure affects intraocular pressure measurement. (United States)

    Gandhi, P D; Gürses-Ozden, R; Liebmann, J M; Ritch, R


    To evaluate the effect of attempted eyelid closure on intraocular pressure measurement. Normal subjects underwent intraocular pressure measurement in both eyes using Goldmann applanation tonometry and Tono-pen XL (Mentor, Inc, Norwell, Massachusetts) by the same examiner holding the eyelids open, both with and without the subject simultaneously attempting forced eyelid closure. Subjects were seated during all measurements and waited 5 minutes between measurements with each instrument; the order of measurement was randomized. Thirty eyes of 15 subjects (six men, nine women) were enrolled. Mean age was 30.5 +/- 5.2 years (range, 24 to 40 years). With Goldmann applanation tonometry, intraocular pressure increased in both eyes with attempted eyelid closure by a mean of 1.5 +/- 2.0 mm Hg (P =.0002, paired t test; range, -2 to 8 mm Hg). With the Tono-pen XL, intraocular pressure also increased in both eyes with attempted eyelid closure by a mean of 1.9 +/- 2.7 mm Hg (P =.0002, paired t test; range, -2 to 9 mm Hg). Tono-pen XL mean intraocular pressure values in both eyes (14.4 +/- 2.3 mm Hg) consistently overestimated those of Goldmann applanation tonometry (13.0 +/- 2.2 mm Hg) by a mean of 1.4 +/- 2.3 mm Hg. Attempted forced eyelid closure is a common and statistically significant source of error in routine outpatient measurement of intraocular pressure and could influence clinical management of glaucoma.

  5. Parallel closure theory for toroidally confined plasmas (United States)

    Ji, Jeong-Young; Held, Eric D.


    We solve a system of general moment equations to obtain parallel closures for electrons and ions in an axisymmetric toroidal magnetic field. Magnetic field gradient terms are kept and treated using the Fourier series method. Assuming lowest order density (pressure) and temperature to be flux labels, the parallel heat flow, friction, and viscosity are expressed in terms of radial gradients of the lowest-order temperature and pressure, parallel gradients of temperature and parallel flow, and the relative electron-ion parallel flow velocity. Convergence of closure quantities is demonstrated as the number of moments and Fourier modes are increased. Properties of the moment equations in the collisionless limit are also discussed. Combining closures with fluid equations parallel mass flow and electric current are also obtained. Work in collaboration with the PSI Center and supported by the U.S. DOE under Grant Nos. DE-SC0014033, DE-SC0016256, and DE-FG02-04ER54746.

  6. Hanford Patrol Academy demolition sites closure plan

    Energy Technology Data Exchange (ETDEWEB)


    The Hanford Site is owned by the U.S. Government and operated by the U.S. Department of Energy, Richland Operations Office. Westinghouse Hanford Company is a major contractor to the U.S. Department of Energy, Richland Operations Office and serves as co-operator of the Hanford Patrol Academy Demolition Sites, the unit addressed in this paper. This document consists of a Hanford Facility Dangerous Waste Part A Permit Application, Form 3 (Revision 4), and a closure plan for the site. An explanation of the Part A Form 3 submitted with this closure plan is provided at the beginning of the Part A section. This Hanford Patrol Academy Demolition Sites Closure Plan submittal contains information current as of December 15, 1994.

  7. Biological constraints do not entail cognitive closure. (United States)

    Vlerick, Michael


    From the premise that our biology imposes cognitive constraints on our epistemic activities, a series of prominent authors--most notably Fodor, Chomsky and McGinn--have argued that we are cognitively closed to certain aspects and properties of the world. Cognitive constraints, they argue, entail cognitive closure. I argue that this is not the case. More precisely, I detect two unwarranted conflations at the core of arguments deriving closure from constraints. The first is a conflation of what I will refer to as 'representation' and 'object of representation'. The second confuses the cognitive scope of the assisted mind for that of the unassisted mind. Cognitive closure, I conclude, cannot be established from pointing out the (uncontroversial) existence of cognitive constraints. Copyright © 2014 Elsevier Ltd. All rights reserved.

  8. Hamiltonian closures in fluid models for plasmas (United States)

    Tassi, Emanuele


    This article reviews recent activity on the Hamiltonian formulation of fluid models for plasmas in the non-dissipative limit, with emphasis on the relations between the fluid closures adopted for the different models and the Hamiltonian structures. The review focuses on results obtained during the last decade, but a few classical results are also described, in order to illustrate connections with the most recent developments. With the hope of making the review accessible not only to specialists in the field, an introduction to the mathematical tools applied in the Hamiltonian formalism for continuum models is provided. Subsequently, we review the Hamiltonian formulation of models based on the magnetohydrodynamics description, including those based on the adiabatic and double adiabatic closure. It is shown how Dirac's theory of constrained Hamiltonian systems can be applied to impose the incompressibility closure on a magnetohydrodynamic model and how an extended version of barotropic magnetohydrodynamics, accounting for two-fluid effects, is amenable to a Hamiltonian formulation. Hamiltonian reduced fluid models, valid in the presence of a strong magnetic field, are also reviewed. In particular, reduced magnetohydrodynamics and models assuming cold ions and different closures for the electron fluid are discussed. Hamiltonian models relaxing the cold-ion assumption are then introduced. These include models where finite Larmor radius effects are added by means of the gyromap technique, and gyrofluid models. Numerical simulations of Hamiltonian reduced fluid models investigating the phenomenon of magnetic reconnection are illustrated. The last part of the review concerns recent results based on the derivation of closures preserving a Hamiltonian structure, based on the Hamiltonian structure of parent kinetic models. Identification of such closures for fluid models derived from kinetic systems based on the Vlasov and drift-kinetic equations are presented, and

  9. Closure properties of Watson-Crick grammars (United States)

    Zulkufli, Nurul Liyana binti Mohamad; Turaev, Sherzod; Tamrin, Mohd Izzuddin Mohd; Azeddine, Messikh


    In this paper, we define Watson-Crick context-free grammars, as an extension of Watson-Crick regular grammars and Watson-Crick linear grammars with context-free grammar rules. We show the relation of Watson-Crick (regular and linear) grammars to the sticker systems, and study some of the important closure properties of the Watson-Crick grammars. We establish that the Watson-Crick regular grammars are closed under almost all of the main closure operations, while the differences between other Watson-Crick grammars with their corresponding Chomsky grammars depend on the computational power of the Watson-Crick grammars which still need to be studied.

  10. Straight line closure of congenital macrostomia

    Directory of Open Access Journals (Sweden)

    Schwarz Richard


    Full Text Available The results of patients operated on by Nepal Cleft Lip and Palate Association (NECLAPA surgeons for congenital macrostomia were prospectively studied between January 2000 and December 2002. There were four males and three females with a median age of 10 years. Three had an associated branchial arch syndrome. In all patients an overlapping repair of orbicularis oris was done. Six patients had a straight line closure with excellent cosmetic results and one a Z-plasty with a more obvious scar. All had a normal appearing commissure. Overlapping orbicularis repair with straight line skin closure for this rare congenital anomaly is recommended.

  11. Uncertainty Quantification of Multi-Phase Closures

    Energy Technology Data Exchange (ETDEWEB)

    Nadiga, Balasubramanya T. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Baglietto, Emilio [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)


    In the ensemble-averaged dispersed phase formulation used for CFD of multiphase ows in nuclear reactor thermohydraulics, closures of interphase transfer of mass, momentum, and energy constitute, by far, the biggest source of error and uncertainty. Reliable estimators of this source of error and uncertainty are currently non-existent. Here, we report on how modern Validation and Uncertainty Quanti cation (VUQ) techniques can be leveraged to not only quantify such errors and uncertainties, but also to uncover (unintended) interactions between closures of di erent phenomena. As such this approach serves as a valuable aide in the research and development of multiphase closures. The joint modeling of lift, drag, wall lubrication, and turbulent dispersion|forces that lead to tranfer of momentum between the liquid and gas phases|is examined in the frame- work of validation of the adiabatic but turbulent experiments of Liu and Banko , 1993. An extensive calibration study is undertaken with a popular combination of closure relations and the popular k-ϵ turbulence model in a Bayesian framework. When a wide range of super cial liquid and gas velocities and void fractions is considered, it is found that this set of closures can be validated against the experimental data only by allowing large variations in the coe cients associated with the closures. We argue that such an extent of variation is a measure of uncertainty induced by the chosen set of closures. We also nd that while mean uid velocity and void fraction pro les are properly t, uctuating uid velocity may or may not be properly t. This aspect needs to be investigated further. The popular set of closures considered contains ad-hoc components and are undesirable from a predictive modeling point of view. Consequently, we next consider improvements that are being developed by the MIT group under CASL and which remove the ad-hoc elements. We use non-intrusive methodologies for sensitivity analysis and calibration (using

  12. Use of dynamic wound closure system in conjunction with vacuum-assisted closure therapy in delayed closure of open abdomen. (United States)

    Salman, A E; Yetişir, F; Aksoy, M; Tokaç, M; Yildirim, M B; Kiliç, M


    Definitive abdominal closure may not be possible for several days or weeks after laparotomy in damage-control surgery, abdominal compartment syndrome and intraabdominal sepsis, until the patient has stabilized. Vacuum-assisted closure (VAC therapy(®), KCI, San Antonio, TX, USA) and abdominal re-approximation anchor system (ABRA, Canica, Almonte, Ontario, Canada) are novel techniques in delayed closure of open abdomen. Our aim is to present the use of these strategies in the management of 7 patients with open abdomen. Between August 2010 and December 2011, 7 patients with severe peritonitis were stabilized by laparotomy and treated with either ABRA system or ABRA system in conjunction with VAC dressing. VAC dressing applied to 4 patients initially and followed by ABRA. ABRA was applied alone to remaining 3 patients. Demographic data and patient characteristics, timing of VAC dressing and ABRA system were recorded. ICU and hospital stay and development of incisional hernia were also recorded. Stage of open abdomen, width of abdominal defect, extent to damage to fascia, and pressure sores were staged. The mean duration with VAC dressing before ABRA application was 18 days. The mean duration of ABRA application was 53 days. The average width of the abdominal defect was 18 cm. The average length of defect was 20.8 cm. Delayed primary abdominal closure was accomplished in 6 patients without further surgery. Incisional hernia with a small abdominal defect developed in 2 patients. Abdominal re-approximation anchor system and VAC dressing can be used separately or in conjunction with each other for closure of delayed open abdomen successfully.

  13. Scalping of light volatile sulfur compounds by wine closures. (United States)

    Silva, Maria A; Jourdes, Michaël; Darriet, Philippe; Teissedre, Pierre-Louis


    Closures have an important influence on wine quality during aging in a bottle. Closures have a direct impact on oxygen exposure and on volatiles scavenging in wine. Model wine solution soaking assays of several types of closures (i.e., natural and technical cork stoppers, synthetic closures, screw caps) with two important wine volatile sulfur compounds led to a considerable reduction in their levels. After 25 days, cork closures and synthetic closures, to a lesser extent, have significantly scavenged hydrogen sulfide and dimethyl sulfide. These compounds have a determinant impact on wine aging bouquet, being largely responsible for "reduced off-flavors". Hydrogen sulfide levels are often not well correlated with the exposure of wine to oxygen or with the permeability of the closure. Its preferential sorption by some types of closures may explain that behavior. Scalping phenomenon should be taken into account when studying wine post-bottling development.

  14. Military Base Closures: Time for Another Round? (United States)


    context and background, see CRS Report 97-305, Military Base Closures: A Brief Historical Review since 1988, by George Siehl , 16 p. 2“Realignment” is...official, to encourage Lockheed Martin Corporation to go after some of the depot maintenance work at McClellan Air Force Base and keep the work in

  15. complementary techniques of percutaneous closure of ductus ...

    African Journals Online (AJOL)


    Jul 7, 2013 ... Background: Patent Ductus Arteriosus (PDA) is a common cardiac malformation whose treatment locally has been surgical ligation via a lateral thoracotomy. Device closure of the ductus was first performed at the Mater hospital in 1999 in a ten year old male using a five millilitre detachable cook coil. In 2000 ...


    Energy Technology Data Exchange (ETDEWEB)

    Langton, C


    The USDOE complex currently has over 330 underground storage tanks that have been used to process and store radioactive waste generated from the production of weapons materials. These tanks contain over 380 million liters of high-level and low-level radioactive waste. The waste consists of radioactively contaminated sludge, supernate, salt cake or calcine. Most of the waste exists at four USDOE locations, the Hanford Site, the Savannah River Site, the Idaho Nuclear Technology and Engineering Center and the West Valley Demonstration Project. A summary of the DOE tank closure activities was first issued in 2001. Since then, regulatory changes have taken place that affect some of the sites and considerable progress has been made in closing tanks. This paper presents an overview of the current regulatory changes and drivers and a summary of the progress in tank closures at the various sites over the intervening six years. A number of areas are addressed including closure strategies, characterization of bulk waste and residual heel material, waste removal technologies for bulk waste, heel residuals and annuli, tank fill materials, closure system modeling and performance assessment programs, lessons learned, and external reviews.

  17. 50 CFR 622.43 - Closures. (United States)


    ... 50 Wildlife and Fisheries 8 2010-10-01 2010-10-01 false Closures. 622.43 Section 622.43 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION... hind, rock hind, yellowmouth grouper, tiger grouper, yellowfin grouper, graysby, and coney. (6...

  18. 300 Area Process Trenches Closure Plan

    Energy Technology Data Exchange (ETDEWEB)

    Luke, S.N.


    Since 1987, Westinghouse Hanford Company has been a major contractor to the US Department of Energy, Richland Operations Office and has served as co-operator of the 300 Area Process Trenches, the waste management unit addressed in this closure plan. For the purposes of the Resource Conservation and Recovery Act, Westinghouse Hanford Company is identified as ``co-operator.`` The 300 Area Process Trenches Closure Plan (Revision 0) consists of a Resource Conservation and Recovery Act Part A Dangerous Waste Permit Application, Form 3 and a Resource Conservation and Recovery Act Closure Plan. An explanation of the Part A Permit Application, Form 3 submitted with this document is provided at the beginning of the Part A Section. The closure plan consists of nine chapters and six appendices. The 300 Area Process Trenches received dangerous waste discharges from research and development laboratories in the 300 Area and from fuels fabrication processes. This waste consisted of state-only toxic (WT02), corrosive (D002), chromium (D007), spent halogenated solvents (F001, F002, and F003), and spent nonhalogented solvent (F005). Accurate records are unavailable concerning the amount of dangerous waste discharged to the trenches. The estimated annual quantity of waste (item IV.B) reflects the total quantity of both regulated and nonregulated waste water that was discharged to the unit.

  19. Spontaneous closure of traumatic CSF otorrhoea following ...

    African Journals Online (AJOL)

    ... the temporal bone extending in to the tympanomastoid area. Patient was managed conservatively with closure of the fistula and resolution of the leakage within 8 days after injury. We report this to further buttress the role of conservative management in CSF fistula. African Journal of Health Sciences Vol. 13 (3-4) 2006: pp.

  20. Individual Consequences of Plant Closures and Cutbacks

    DEFF Research Database (Denmark)

    Andersen, Steen


    This thesis describes the segment of unemployment which has its origin in major closures and cutbacks. The argument for this is to make it possible to describe and to analyse a flow into and a flow out of a population of unemployed. Given a major dismissal the following questions are to be answered...

  1. The Story of a Charter School Closure. (United States)

    Flynn, Susan L.; Arguelles, Lourdes


    The story of a charter school closure is told from the perspectives of students, parents, teachers, and community members, who felt that the sponsoring district revoked the charter for political reasons despite broad local support. The experience underscores the necessity of publicly subjecting the relationship of the public school system and the…

  2. Collective Protection (COLPRO) Novel Closures Testing (United States)


    miosis level) or a predetermined exposure value, as specified by the test requirement document. MINICAMS®-like instruments have a detection range of...Performance. Candidate novel closures must pass user-defined requirements. The pass/fail requirements may depend on miosis hazard level, inhalation

  3. Modeling elephant-mediated cascading effects of water point closure. (United States)

    Hilbers, Jelle P; Van Langevelde, Frank; Prins, Herbert H T; Grant, C C; Peel, Mike J S; Coughenour, Michael B; De Knegt, Henrik J; Slotow, Rob; Smit, Izak P J; Kiker, Greg A; De Boer, Willem F


    Wildlife management to reduce the impact of wildlife on their habitat can be done in several ways, among which removing animals (by either culling or translocation) is most often used. There are, however, alternative ways to control wildlife densities, such as opening or closing water points. The effects of these alternatives are poorly studied. In this paper, we focus on manipulating large herbivores through the closure of water points (WPs). Removal of artificial WPs has been suggested in order to change the distribution of African elephants, which occur in high densities in national parks in Southern Africa and are thought to have a destructive effect on the vegetation. Here, we modeled the long-term effects of different scenarios of WP closure on the spatial distribution of elephants, and consequential effects on the vegetation and other herbivores in Kruger National Park, South Africa. Using a dynamic ecosystem model, SAVANNA, scenarios were evaluated that varied in availability of artificial WPs; levels of natural water; and elephant densities. Our modeling results showed that elephants can indirectly negatively affect the distributions of meso-mixed feeders, meso-browsers, and some meso-grazers under wet conditions. The closure of artificial WPs hardly had any effect during these natural wet conditions. Under dry conditions, the spatial distribution of both elephant bulls and cows changed when the availability of artificial water was severely reduced in the model. These changes in spatial distribution triggered changes in the spatial availability of woody biomass over the simulation period of 80 years, and this led to changes in the rest of the herbivore community, resulting in increased densities of all herbivores, except for giraffe and steenbok, in areas close to rivers. The spatial distributions of elephant bulls and cows showed to be less affected by the closure of WPs than most of the other herbivore species. Our study contributes to ecologically

  4. Tissue adhesives for closure of surgical incisions. (United States)

    Dumville, Jo C; Coulthard, Paul; Worthington, Helen V; Riley, Philip; Patel, Neil; Darcey, James; Esposito, Marco; van der Elst, Maarten; van Waes, Oscar J F


    Sutures (stitches), staples and adhesive tapes have been used for many years as methods of wound closure, but tissue adhesives have entered clinical practice more recently. Closure of wounds with sutures enables the closure to be meticulous, but the sutures may show tissue reactivity and can require removal. Tissue adhesives offer the advantages of an absence of risk of needlestick injury and no requirement to remove sutures later. Initially, tissue adhesives were used primarily in emergency room settings, but this review looks at the use of tissue adhesives in the operating room/theatre where surgeons are using them increasingly for the closure of surgical skin incisions. To determine the effects of various tissue adhesives compared with conventional skin closure techniques for the closure of surgical wounds. In March 2014 for this second update we searched the Cochrane Wounds Group Specialised Register; The Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library); Ovid MEDLINE; Ovid MEDLINE (In-Process & Other Non-Indexed Citations); Ovid EMBASE and EBSCO CINAHL. We did not restrict the search and study selection with respect to language, date of publication or study setting. Only randomised controlled trials were eligible for inclusion. We conducted screening of eligible studies, data extraction and risk of bias assessment independently and in duplicate. We expressed results as random-effects models using mean difference for continuous outcomes and risk ratios (RR) with 95% confidence intervals (CI) for dichotomous outcomes. We investigated heterogeneity, including both clinical and methodological factors. This second update of the review identified 19 additional eligible trials resulting in a total of 33 studies (2793 participants) that met the inclusion criteria. There was low quality evidence that sutures were significantly better than tissue adhesives for reducing the risk of wound breakdown (dehiscence; RR 3.35; 95% CI 1.53 to 7

  5. Primary closure after carotid endarterectomy is not inferior to other closure techniques. (United States)

    Avgerinos, Efthymios D; Chaer, Rabih A; Naddaf, Abdallah; El-Shazly, Omar M; Marone, Luke; Makaroun, Michel S


    Primary closure after carotid endarterectomy (CEA) has been much maligned as an inferior technique with worse outcomes than in patch closure. Our purpose was to compare perioperative and long-term results of different CEA closure techniques in a large institutional experience. A consecutive cohort of CEAs between January 1, 2000, and December 31, 2010, was retrospectively analyzed. Closure technique was used to divide patients into three groups: primary longitudinal arteriotomy closure (PRC), patch closure (PAC), and eversion closure (EVC). End points were perioperative events, long-term strokes, and restenosis ≥70%. Multivariate regression models were used to assess the effect of baseline predictors. There were 1737 CEA cases (bilateral, 143; mean age, 71.4 ± 9.3 years; 56.2% men; 35.3% symptomatic) performed during the study period with a mean clinical follow-up of 49.8 ± 36.4 months (range, 0-155 months). More men had primary closure, but other demographic and baseline symptoms were similar between groups. Half the patients had PAC, with the rest evenly distributed between PRC and EVC. The rate of nerve injury was 2.7%, the rate of reintervention for hematoma was 1.5%, and the length of hospital stay was 2.4 ± 3.0 days, with no significant differences among groups. The combined stroke and death rate was 2.5% overall and 3.9% and 1.7% in the symptomatic and asymptomatic cohort, respectively. Stroke and death rates were similar between groups: PRC, 11 (2.7%); PAC, 19 (2.2%); EVC, 13 (2.9%). Multivariate analysis showed baseline symptomatic disease (odds ratio, 2.4; P = .007) and heart failure (odds ratio, 3.1; P = .003) as predictors of perioperative stroke and death, but not the type of closure. Cox regression analysis demonstrated, among other risk factors, no statin use (hazard ratio, 2.1; P = .008) as a predictor of ipsilateral stroke and severe (glomerular filtration rate <30 mL/min/1.73 m(2)) renal insufficiency (hazard ratio, 2.6; P

  6. Emergence time in forest bats: the influence of canopy closure (United States)

    Russo, Danilo; Cistrone, Luca; Jones, Gareth


    The role of the forest canopy in protecting bats roosting in forest from predators is poorly known. We analysed the effect of canopy closure on emergence time in Barbastella barbastellus in a mountainous area of central Italy. We used radio-tracking to locate roosts and filmed evening emergence. Comparisons were made between roosts in open areas and those in dense forest. Median emergence time and illuminance were correlated. Moreover, from pregnancy to late lactation bats emerged progressively earlier, probably because of the exceptionally high wing loading affecting pregnant bats and the high energy demand of lactation. A significant influence of canopy closure on median emergence time was revealed after adjusting for the effects of light and reproductive state. Bats in open habitat emerged later than those roosting beneath closed canopy. In cluttered habitats, predators relying on vision may find it more difficult to detect and catch bats at light levels which would offer more chances of success when attacking prey in open habitats. Bats in dense forest are less vulnerable to predators and may take advantage of an earlier emergence by prolonging foraging. Although more vulnerable, lactating females roosting at open sites may benefit from warmer roosting conditions. Roosts in dense forest may be preferred under intense predation pressure. Forest management should favour canopy heterogeneity to provide bats with a range of roosting conditions. Our work emphasises the role of a fine-grained spatial scale in the roosting ecology of forest bats.

  7. Permanent Closure of the TAN-664 Underground Storage Tank

    Energy Technology Data Exchange (ETDEWEB)

    Bradley K. Griffith


    This closure package documents the site assessment and permanent closure of the TAN-664 gasoline underground storage tank in accordance with the regulatory requirements established in 40 CFR 280.71, 'Technical Standards and Corrective Action Requirements for Owners and Operators of Underground Storage Tanks: Out-of-Service UST Systems and Closure.'

  8. Evolution of Fascial Closure Optimization in Damage Control Laparotomy. (United States)

    Lauerman, Margaret H; Dubose, Joseph J; Stein, Deborah M; Galvagno, Samuel M; Bradley, Matthew J; Diaz, Jose; Scalea, Thomas M


    Management of patients undergoing damage control laparotomy (DCL) involves many surgical, medical, and logistical factors. Ideal patient management optimizing fascial closure with regard to timing and closure techniques remains unclear. A retrospective review of patients undergoing DCL from 2000 to 2012 at an urban Level I trauma center was undertaken. Mortality of DCL decreased over the study period from 62.5 to 34.6 per cent, whereas enterocutaneous fistula rate decreased from 12.5 to 3.8 per cent. Delayed primary fascial closure rate improved from 22.2 to 88.2 per cent. Time to closure (P fascial closure. In subgroup analysis, achievement of delayed primary fascial closure was decreased with time to closure after one week (91.7% vs 52.0%, P = 0.002) and time to first attempted closure after two days (86.5% vs 70.0%, P = 0.042). In multivariate analysis, time to closure (odds ratio: 0.13, 95% confidence interval: 0.04-0.39; P fascial closure. Timing of attempted closure plays a significant role in attaining delayed primary fascial closure, highlighting the importance of early re-exploration.

  9. 9 CFR 381.301 - Containers and closures. (United States)


    ... 9 Animals and Animal Products 2 2010-01-01 2010-01-01 false Containers and closures. 381.301... Containers and closures. (a) Examination and cleaning of empty containers. (1) Empty containers, closures... and free of structural defects and damage that may affect product or container integrity. Such an...

  10. 9 CFR 318.301 - Containers and closures. (United States)


    ... 9 Animals and Animal Products 2 2010-01-01 2010-01-01 false Containers and closures. 318.301... Canning and Canned Products § 318.301 Containers and closures. (a) Examination and cleaning of empty containers. (1) Empty containers, closures, and flexible pouch roll stock shall be evaluated by the...

  11. The potential migration effect of rural hospital closures

    DEFF Research Database (Denmark)

    Sørensen, Jens Fyhn Lykke


    Rural hospital closures are high on the current health care agenda in Denmark. One raised concern is that rural hospital closures may further decrease population numbers in rural areas, as closures may induce some residents to move away from affected areas, i.e. closer to health care services els...

  12. Vacuum-assisted closure in the treatment of poststernotomy mediastinitis

    NARCIS (Netherlands)

    Obdeijn, MC; de Lange, M.Y.; Lichtendahl, DHE; de Boer, Willem


    A new technique using vacuum-assist-ed closure was successfully applied in 3 patients with poststernotomy mediastinitis. After surgical debridement, this vacuum-assisted closure technique has made it possible to avoid the need for secondary surgical closure (including direct secondary surgical

  13. The Rising Rate of Rural Hospital Closures. (United States)

    Kaufman, Brystana G; Thomas, Sharita R; Randolph, Randy K; Perry, Julie R; Thompson, Kristie W; Holmes, George M; Pink, George H


    Since 2010, the rate of rural hospital closures has increased significantly. This study is a preliminary look at recent closures and a formative step in research to understand the causes and the impact on rural communities. The 2009 financial performance and market characteristics of rural hospitals that closed from 2010 through 2014 were compared to rural hospitals that remained open during the same period, stratified by critical access hospitals (CAHs) and other rural hospitals (ORHs). Differences were tested using Pearson's chi-square (categorical variables) and Wilcoxon rank test of medians. The relationships between negative operating margin and (1) market factors and (2) utilization/staffing factors were explored using logistic regression. In 2009, CAHs that subsequently closed from 2010 through 2014 had, in general, lower levels of profitability, liquidity, equity, patient volume, and staffing. In addition, ORHs that closed had smaller market shares and operated in markets with smaller populations compared to ORHs that remained open. Odds of unprofitability were associated with both market and utilization factors. Although half of the closed hospitals ceased providing health services altogether, the remainder have since converted to an alternative health care delivery model. Financial and market characteristics appear to be associated with closure of rural hospitals from 2010 through 2014, suggesting that it is possible to identify hospitals at risk of closure. As closure rates show no sign of abating, it is important to study the drivers of distress in rural hospitals, as well as the potential for alternative health care delivery models. © 2015 National Rural Health Association.

  14. Results of vacuum assisted wound closure application. (United States)

    Atay, Tolga; Burc, Halil; Baykal, Yakup Barbaros; Kirdemir, Vecihi


    In recent past, various methods have been used for wound treatment purpose. In this study, we aimed to compare our results established from the vacuum-assisted wound closure method, which has gained popularity day by day, with the literature. A total of 48 patients, who received vacuum-assisted wound closure treatment in our clinic between 2007and 2010, were included in this study. Etiological distribution of the patients was as follows: 32 traumatic, 6 pressure sore, 9 diabetic, and 1 iliac disarticulation. All cases were evaluated in terms of age, gender, etiology, period of treatment, and size of the wound. In the patients studied, 42 were men (87.5 %) and 6 were women (12.5 %). Mean age of the patients was 39.6 years (11-61 years). All of our traumatic patients suffered from open fracture. After the vacuum-assisted wound closure application, wound size reduced by 28.8 %, while the mean area of the surface of the wound was 94.7 cm(2) (13.7-216.3 cm(2)) on average. After the wounds became ready for surgery, 15 of them were treated with split-thickness grafting, 9 of them were treated with secondary suture, 18 of them were treated with full-thickness grafting, and 6 of them were treated with flap. Average period of the application of vacuum-assisted wound closure was 11.6 days (7-15 days). Results of vacuum-assisted wound closure can be regarded as satisfactory when cases are selected properly. This system has three different effect mechanisms. Firstly, it increases local blood flow on the wound bed. Secondly, cell proliferation is triggered following the mechanic stress. Thirdly, vacuum removes the proteases from the environment which obstructs healing. Therefore, it is intended to prepare alive wound bed which is required for subsequent soft tissue reconstructions.

  15. Summary of Group Development and Testing for Single Shell Tank Closure at Hanford

    Energy Technology Data Exchange (ETDEWEB)

    Harbour, John, R.


    This report is a summary of the bench-scale and large scale experimental studies performed by Savannah River National Laboratory for CH2M HILL to develop grout design mixes for possible use in producing fill materials as a part of Tank Closure of the Single-Shell Tanks at Hanford. The grout development data provided in this report demonstrates that these design mixes will produce fill materials that are ready for use in Hanford single shell tank closure. The purpose of this report is to assess the ability of the proposed grout specifications to meet the current requirements for successful single shell tank closure which will include the contracting of services for construction and operation of a grout batch plant. The research and field experience gained by SRNL in the closure of Tanks 17F and 20F at the Savannah River Site was leveraged into the grout development efforts for Hanford. It is concluded that the three Hanford grout design mixes provide fill materials that meet the current requirements for successful placement. This conclusion is based on the completion of recommended testing using Hanford area materials by the operators of the grout batch plant. This report summarizes the regulatory drivers and the requirements for grout mixes as tank fill material. It is these requirements for both fresh and cured grout properties that drove the development of the grout formulations for the stabilization, structural and capping layers.

  16. 324 Building radiochemical engineering cells, high-level vault, low-level vault, and associated areas closure plan

    Energy Technology Data Exchange (ETDEWEB)

    Barnett, J.M.


    The Hanford Site, located adjacent to and north of Richland, Washington, is operated by the US Department of Energy, Richland Operations Office (RL). The 324 Building is located in the 300 Area of the Hanford Site. The 324 Building was constructed in the 1960s to support materials and chemical process research and development activities ranging from laboratory/bench-scale studies to full engineering-scale pilot plant demonstrations. In the mid-1990s, it was determined that dangerous waste and waste residues were being stored for greater than 90 days in the 324 Building Radiochemical Engineering Cells (REC) and in the High-Level Vault/Low-Level Vault (HLV/LLV) tanks. [These areas are not Resource Conservation and Recovery Act of 1976 (RCRA) permitted portions of the 324 Building.] Through the Hanford Federal Facility Agreement and Consent Order (Tri-Party Agreement) Milestone M-89, agreement was reached to close the nonpermitted RCRA unit in the 324 Building. This closure plan, managed under TPA Milestone M-20-55, addresses the identified building areas targeted by the Tri-Party Agreement and provides commitments to achieve the highest degree of compliance practicable, given the special technical difficulties of managing mixed waste that contains high-activity radioactive materials, and the physical limitations of working remotely in the areas within the subject closure unit. This closure plan is divided into nine chapters. Chapter 1.0 provides the introduction, historical perspective, 324 Building history and current mission, and the regulatory basis and strategy for managing the closure unit. Chapters 2.0, 3.0, 4.0, and 5.0 discuss the detailed facility description, process information, waste characteristics, and groundwater monitoring respectively. Chapter 6.0 deals with the closure strategy and performance standard, including the closure activities for the B-Cell, D-Cell, HLV, LLV; piping and miscellaneous associated building areas. Chapter 7.0 addresses the

  17. Closure versus non-closure of fascial defects in laparoscopic ventral and incisional hernia repairs: a review of the literature. (United States)

    Suwa, Katsuhito; Okamoto, Tomoyoshi; Yanaga, Katsuhiko


    The laparoscopic technique for repairing ventral and incisional hernias (VIH) is now well established. However, several issues related to laparoscopic VIH repair, such as the high recurrence rate for hernias with large fascial defects and in extremely obese patients, are yet to be resolved. Additional problems include seroma formation, mesh bulging/eventration, and non-restoration of the abdominal wall rigidity/function with only bridging of the hernial orifice using standard laparoscopic intraperitoneal onlay mesh repair (sIPOM). To solve these problems, laparoscopic fascial defect closure with IPOM reinforcement (IPOM-Plus) has been introduced in the past decade, and a few studies have reported satisfactory outcomes. Although detailed techniques for fascial defect closure and handling of the mesh have been published, standardized techniques are yet to be established. We reviewed the literature on IPOM-Plus in the PubMed database and identified 16 reports in which the recurrence rate, incidence of seroma formation, and incidence of mesh bulging were 0-7.7, 0-11.4, and 0 %, respectively. Several comparison studies between sIPOM and IPOM-Plus seem to suggest that IPOM-Plus is associated with more favorable surgical outcomes; however, larger-scale studies are essential.

  18. Temporary Closure of the Open Abdomen: A Systematic Review on Delayed Primary Fascial Closure in Patients with an Open Abdomen

    NARCIS (Netherlands)

    Boele van Hensbroek, P.; Wind, J.; Dijkgraaf, M.G.W.; Busch, O.R.C.; Goslings, J.C.


    Background This study was designed to systematically review the literature to assess which temporary abdominal closure (TAC) technique is associated with the highest delayed primary fascial closure (FC) rate. In some cases of abdominal trauma or infection, edema or packing precludes fascial closure

  19. Suitability of Exoseal Vascular Closure Device for Antegrade Femoral Artery Puncture Site Closure

    Energy Technology Data Exchange (ETDEWEB)

    Schmelter, Christopher, E-mail:; Liebl, Andrea; Poullos, Nektarios [Klinikum Ingolstadt, Department of Diagnostic and Interventional Radiology (Germany); Ruppert, Volker [Klinikum Ingolstadt, Department of Vascular Surgery (Germany); Vorwerk, Dierk [Klinikum Ingolstadt, Department of Diagnostic and Interventional Radiology (Germany)


    Purpose. To assess the efficacy and safety of the Exoseal vascular closure device for antegrade puncture of the femoral artery. Methods. In a prospective study from February 2011 to January 2012, a total of 93 consecutive patients received a total of 100 interventional procedures via an antegrade puncture of the femoral artery. An Exoseal vascular closure device (6F) was used for closure in all cases. Puncture technique, duration of manual compression, and use of compression bandages were documented. All patients were monitored by vascular ultrasound and color-coded duplex sonography of their respective femoral artery puncture site within 12 to 36 h after angiography to check for vascular complications. Results. In 100 antegrade interventional procedures, the Exoseal vascular closure device was applied successfully for closure of the femoral artery puncture site in 96 cases (96 of 100, 96.0 %). The vascular closure device could not be deployed in one case as a result of kinking of the vascular sheath introducer and in three cases because the bioabsorbable plug was not properly delivered to the extravascular space adjacent to the arterial puncture site, but instead fully removed with the delivery system (4.0 %). Twelve to 36 h after the procedure, vascular ultrasound revealed no complications at the femoral artery puncture site in 93 cases (93.0 %). Minor vascular complications were found in seven cases (7.0 %), with four cases (4.0 %) of pseudoaneurysm and three cases (3.0 %) of significant late bleeding, none of which required surgery. Conclusion. The Exoseal vascular closure device was safely used for antegrade puncture of the femoral artery, with a high rate of procedural success (96.0 %), a low rate of minor vascular complications (7.0 %), and no major adverse events.

  20. Application of electron closures in extended MHD (United States)

    Held, Eric; Adair, Brett; Taylor, Trevor


    Rigorous closure of the extended MHD equations in plasma fluid codes includes the effects of electron heat conduction along perturbed magnetic fields and contributions of the electron collisional friction and stress to the extended Ohms law. In this work we discuss application of a continuum numerical solution to the Chapman-Enskog-like electron drift kinetic equation using the NIMROD code. The implementation is a tightly-coupled fluid/kinetic system that carefully addresses time-centering in the advance of the fluid variables with their kinetically-computed closures. Comparisons of spatial accuracy, computational efficiency and required velocity space resolution are presented for applications involving growing magnetic islands in cylindrical and toroidal geometry. The reduction in parallel heat conduction due to particle trapping in toroidal geometry is emphasized. Work supported by DOE under Grant Nos. DE-FC02-08ER54973 and DE-FG02-04ER54746.

  1. Closure measurements of naturally initiating small cracks (United States)

    Sharpe, W. N., Jr.; Su, X.


    The initiation and growth of cracks in smooth 2024-T3 aluminum specimens have been investigated using acetate replicas. Crack opening displacements were measured as a function of load at several positions along the crack as it grew across the thickness of the specimen and became a through-the-thickness crack of a few millimeters in length. Tests run for R-ratios of 0.5, 0.0 and -1.0 showed that closure loads were well predicted by Newman's (1984) model. It is noted that small cracks grow slightly faster than would be predicted by long-crack data, and it is suggested that effects other than plasticity-induced closure must be taken into account.

  2. The Galois closure of Drinfeld modular towers

    DEFF Research Database (Denmark)

    Bassa, Alp; Beelen, Peter


    In this article we study Drinfeld modular curves X0(pn) associated to congruence subgroups Γ0(pn) of GL(2,Fq[T]) where p is a prime of Fq[T]. For n>r>0 we compute the extension degrees and investigate the structure of the Galois closures of the covers X0(pn)→X0(pr) and some of their variations...

  3. Calcined solids storage facility closure study

    Energy Technology Data Exchange (ETDEWEB)

    Dahlmeir, M.M.; Tuott, L.C.; Spaulding, B.C. [and others


    The disposal of radioactive wastes now stored at the Idaho National Engineering and Environmental Laboratory is currently mandated under a {open_quotes}Settlement Agreement{close_quotes} (or {open_quotes}Batt Agreement{close_quotes}) between the Department of Energy and the State of Idaho. Under this agreement, all high-level waste must be treated as necessary to meet the disposal criteria and disposed of or made road ready to ship from the INEEL by 2035. In order to comply with this agreement, all calcined waste produced in the New Waste Calcining Facility and stored in the Calcined Solids Facility must be treated and disposed of by 2035. Several treatment options for the calcined waste have been studied in support of the High-Level Waste Environmental Impact Statement. Two treatment methods studied, referred to as the TRU Waste Separations Options, involve the separation of the high-level waste (calcine) into TRU waste and low-level waste (Class A or Class C). Following treatment, the TRU waste would be sent to the Waste Isolation Pilot Plant (WIPP) for final storage. It has been proposed that the low-level waste be disposed of in the Tank Farm Facility and/or the Calcined Solids Storage Facility following Resource Conservation and Recovery Act closure. In order to use the seven Bin Sets making up the Calcined Solids Storage Facility as a low-level waste landfill, the facility must first be closed to Resource Conservation and Recovery Act (RCRA) standards. This study identifies and discusses two basic methods available to close the Calcined Solids Storage Facility under the RCRA - Risk-Based Clean Closure and Closure to Landfill Standards. In addition to the closure methods, the regulatory requirements and issues associated with turning the Calcined Solids Storage Facility into an NRC low-level waste landfill or filling the bin voids with clean grout are discussed.

  4. Comprehensive Approaches to Multiphase Flows in Geophysics - Application to nonisothermal, nonhomogenous, unsteady, large-scale, turbulent dusty clouds I. Hydrodynamic and Thermodynamic RANS and LES Models

    Energy Technology Data Exchange (ETDEWEB)

    S. Dartevelle


    The objective of this manuscript is to fully derive a geophysical multiphase model able to ''accommodate'' different multiphase turbulence approaches; viz., the Reynolds Averaged Navier-Stokes (RANS), the Large Eddy Simulation (LES), or hybrid RANSLES. This manuscript is the first part of a larger geophysical multiphase project--lead by LANL--that aims to develop comprehensive modeling tools for large-scale, atmospheric, transient-buoyancy dusty jets and plume (e.g., plinian clouds, nuclear ''mushrooms'', ''supercell'' forest fire plumes) and for boundary-dominated geophysical multiphase gravity currents (e.g., dusty surges, diluted pyroclastic flows, dusty gravity currents in street canyons). LES is a partially deterministic approach constructed on either a spatial- or a temporal-separation between the large and small scales of the flow, whereas RANS is an entirely probabilistic approach constructed on a statistical separation between an ensemble-averaged mean and higher-order statistical moments (the so-called ''fluctuating parts''). Within this specific multiphase context, both turbulence approaches are built up upon the same phasic binary-valued ''function of presence''. This function of presence formally describes the occurrence--or not--of any phase at a given position and time and, therefore, allows to derive the same basic multiphase Navier-Stokes model for either the RANS or the LES frameworks. The only differences between these turbulence frameworks are the closures for the various ''turbulence'' terms involving the unknown variables from the fluctuating (RANS) or from the subgrid (LES) parts. Even though the hydrodynamic and thermodynamic models for RANS and LES have the same set of Partial Differential Equations, the physical interpretations of these PDEs cannot be the same, i.e., RANS models an averaged field, while LES simulates a

  5. Folate receptors and neural tube closure. (United States)

    Saitsu, Hirotomo


    Neural tube defects (NTD) are among the most common human congenital malformations, affecting 0.5-8.0/1000 of live births. Human clinical trials have shown that periconceptional folate supplementation significantly decreases the occurrence of NTD in offspring. However, the mechanism by which folate acts on NTD remains largely unknown. Folate receptor (Folr) is one of the three membrane proteins that mediate cellular uptake of folates. Recent studies suggest that mouse Folr1 (formerly referred to as Fbp1) is essential for neural tube closure. Therefore, we examined spatial and temporal expression patterns of Folr1 in developing mouse embryos, showing a close association between Folr1 and anterior neural tube closure. Transient transgenic analysis was performed using lacZ as a reporter; we identified a 1.1-kb enhancer that directs lacZ expression in the neural tube and optic vesicle in a manner that is similar to endogenous Folr1. The 1.1-kb enhancer sequences were highly conserved between humans and mice, suggesting that human FOLR1 is associated with anterior neural tube closure in humans. Several experimental studies in mice and human epidemiological and genetics studies have suggested that folate receptor abnormalities are involved in a portion of human NTDs, although the solo defect of FOLR1 did not cause NTD. © 2017 Japanese Teratology Society.

  6. Phenomenology of convection-parameterization closure

    Directory of Open Access Journals (Sweden)

    J.-I. Yano


    Full Text Available Closure is a problem of defining the convective intensity in a given parameterization. In spite of many years of efforts and progress, it is still considered an overall unresolved problem. The present article reviews this problem from phenomenological perspectives. The physical variables that may contribute in defining the convective intensity are listed, and their statistical significances identified by observational data analyses are reviewed. A possibility is discussed for identifying a correct closure hypothesis by performing a linear stability analysis of tropical convectively coupled waves with various different closure hypotheses. Various individual theoretical issues are considered from various different perspectives. The review also emphasizes that the dominant physical factors controlling convection differ between the tropics and extra-tropics, as well as between oceanic and land areas. Both observational as well as theoretical analyses, often focused on the tropics, do not necessarily lead to conclusions consistent with our operational experiences focused on midlatitudes. Though we emphasize the importance of the interplays between these observational, theoretical and operational perspectives, we also face challenges for establishing a solid research framework that is universally applicable. An energy cycle framework is suggested as such a candidate.

  7. Creativity & Cognitive Closure (Creatividad y cierre cognitivo

    Directory of Open Access Journals (Sweden)

    Melike Hazir


    Full Text Available Abstract The aim of this paper is to present the relationship between the need for cognitive closure (NFC and creativity. In light of previous research, a theoretical foundation is established for the term creativity. Next the social-cognitive phenomenon of the need for cognitive closure is explained based on the theory of Kruglanski and Webster, and considering the tendencies of urgency and permanency. Conclusion: The role of creativity is to control cognitive closure in order to solve problems that arise during the learning process and usually during the life. Resumen El objetivo de este trabajo es presentar la relación entre la necesidad de cierre cognitivo (NCC y la creatividad. A la luz de las investigaciones realizadas, se establece la base teórica para el término de creatividad y la explica del fenómeno socio-cognitivo de necesidad de cierre cognitivo en base a la teoría de Kruglanski y Webster, teniendo en cuenta las tendencias de urgencia y permanencia. Conclusión: La creatividad tiene un papel importante de control del cierre cognitivo con el fin de resolver los problemas que surjan durante el proceso de aprendizaje y en general durante la vida.

  8. A sub-grid, mixture-fraction-based thermodynamic equilibrium model for gas phase combustion in FIRETEC: development and results (United States)

    M. M. Clark; T. H. Fletcher; R. R. Linn


    The chemical processes of gas phase combustion in wildland fires are complex and occur at length-scales that are not resolved in computational fluid dynamics (CFD) models of landscape-scale wildland fire. A new approach for modelling fire chemistry in HIGRAD/FIRETEC (a landscape-scale CFD wildfire model) applies a mixture– fraction model relying on thermodynamic...

  9. Risk and Performance Analyses Supporting Closure of WMA C at the Hanford Site in Southeast Washington

    Energy Technology Data Exchange (ETDEWEB)

    Eberlein, Susan J.; Bergeron, Marcel P.; Kemp, Christopher J.


    The Office of River Protection under the U.S. Department of Energy (DOE) is pursuing closure of the Single-Shell Tank (SST) Waste Management Area (WMA) C as stipulated by the Hanford Federal Facility Agreement and Consent Order (HFFACO) under federal requirements and work tasks will be done under the State-approved closure plans and permits. An initial step in meeting the regulatory requirements is to develop a baseline risk assessment representing current conditions based on available characterization data and information collected at the WMA C location. The baseline risk assessment will be supporting a Resource Conservation and Recovery Act of 1976 (RCRA) Field Investigation (RFI)/Corrective Measures Study (CMS) for WMA closure and RCRA corrective action. Complying with the HFFACO conditions also involves developing a long-term closure Performance Assessment (PA) that evaluates human health and environmental impacts resulting from radionuclide inventories in residual wastes remaining in WMA C tanks and ancillary equipment. This PA is being developed to meet the requirements necessary for closure authorization under DOE Order 435.1 and Washington State Hazardous Waste Management Act. To meet the HFFACO conditions, the long-term closure risk analysis will include an evaluation of human health and environmental impacts from hazardous chemical inventories along with other performance Comprehensive Environmental Response, Compensation, and Liability Act Appropriate and Applicable Requirements (CERCLA ARARs) in residual wastes left in WMA C facilities after retrieval and removal. This closure risk analysis is needed to needed to comply with the requirements for permitted closure. Progress to date in developing a baseline risk assessment of WMA C has involved aspects of an evaluation of soil characterization and groundwater monitoring data collected as a part of the RFI/CMS and RCRA monitoring. Developing the long-term performance assessment aspects has involved the

  10. Umbilical trocar site closure with Berci's needle after laparoscopic cholecystectomy. (United States)

    Calik, Adnan; Yucel, Yusuf; Topaloglu, Serdar; Hos, Gultekin; Aktas, Aydin; Piskin, Burhan


    The umbilical region is particularly susceptible for development of incisional hernia after laparoscopic cholecystectomy (LC). To evaluate the effects of port-closure techniques on the complications seen after umbilical port-site closure, we compared closure with Berci's needle and the standard technique of a hand-sutured closure. A hundred patients underwent LC were randomly divided into two groups. We evaluated the required time for closure, the security of techniques and the factors affecting postoperative complications for both closure groups in a prospective manner. Closure of the umbilical port site was performed faster with the Berci's needle compared to standard hand-sutured technique. Postoperative hospital stay and complication rates were not altered significantly depend on the closure technique. Skin dimpling on the trocar site was observed predominantly after closure with Berci's needle. Spontaneous improvement on skin dimpling was observed within the 2 weeks after operation in all patients. During the follow-up period, there was no trocar site hernia observed in the study group. Closure of the umbilical port site with Berci's needle is found as an effective and safe method for laparoscopic cholecystectomy.

  11. Techniques for Abdominal Wall Closure after Damage Control Laparotomy: From Temporary Abdominal Closure to Early/Delayed Fascial Closure-A Review. (United States)

    Huang, Qian; Li, Jieshou; Lau, Wan-Yee


    Open abdomen (OA) has been an effective treatment for abdominal catastrophes in traumatic and general surgery. However, management of patients with OA remains a formidable task for surgeons. The central goal of OA is closure of fascial defect as early as is clinically feasible without precipitating abdominal compartment syndrome. Historically, techniques such as packing, mesh, and vacuum-assisted closure have been developed to assist temporary abdominal closure, and techniques such as components separation, mesh-mediated traction, bridging fascial defect with permanent synthetic mesh, or biologic mesh have also been attempted to achieve early primary fascial closure, either alone or in combined use. The objective of this review is to present the challenges of these techniques for OA with a goal of early primary fascial closure, when the patient's physiological condition allows.

  12. 3718-F Alkali Metal Treatment and Storage Facility Closure Plan

    Energy Technology Data Exchange (ETDEWEB)



    Since 1987, Westinghouse Hanford Company has been a major contractor to the U.S. Department of Energy-Richland Operations Office and has served as co-operator of the 3718-F Alkali Metal Treatment and Storage Facility, the waste management unit addressed in this closure plan. The closure plan consists of a Part A Dangerous waste Permit Application and a RCRA Closure Plan. An explanation of the Part A Revision (Revision 1) submitted with this document is provided at the beginning of the Part A section. The closure plan consists of 9 chapters and 5 appendices. The chapters cover: introduction; facility description; process information; waste characteristics; groundwater; closure strategy and performance standards; closure activities; postclosure; and references.

  13. Sub-Grid-Scale Description of Turbulent Magnetic Reconnection in Magnetohydrodynamics

    CERN Document Server

    Widmer, Fabien; Yokoi, Nobumitsu


    Magnetic reconnection requires, at least locally, a non-ideal plasma response. In collisionless space and astrophysical plasmas, turbulence could permit this instead of the too rare binary collisions. We investigated the influence of turbulence on the reconnection rate in the framework of a single fluid compressible MHD approach. The goal is to find out, whether unresolved, sub-grid for MHD simulations, turbulence can enhance the reconnection process in high Reynolds number astrophysical plasma. We solve, simultaneously with the grid-scale MHD equations, evolution equations for the sub-grid turbulent energy and cross helicity according to Yokoi's model (Yokoi (2013)) where turbulence is self-generated and -sustained through the inhomogeneities of the mean fields. Simulations of Harris and force free sheets confirm the results of Higashimori et al. (2013) and new results are obtained about the dependence on resistivity for large Reynolds number as well as guide field effects. The amount of energy transferred f...

  14. Left atrial appendage closure: a new technique for clinical practice. (United States)

    John Camm, A; Colombo, Antonio; Corbucci, Giorgio; Padeletti, Luigi


    Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia. It is associated with increased risk for stroke mainly due to cardiac embolism from the left atrial appendage (LAA). Occlusion of the LAA by means of a device represents a valid alternative to oral anticoagulation, mainly in patients who cannot tolerate this therapy because of a high bleeding risk. Recent data on the endocardial device WATCHMAN show encouraging results for this patient population in terms of stroke risk reduction compared to the expected rate as well as in terms of implant success. This article reviews all relevant publications related to the main surgical and transcatheter devices used for LAA closure (LAAC). PROTECT-AF, the first prospective randomized trial conducted on this technique, showed that LAA occlusion using the WATCHMAN was noninferior to warfarin for a combined end-point in patients with nonvalvular AF. There is a lack of large-scale randomized trials on long-term stroke risk in patients submitted to LAAC. Most studies are relatively small and focus on the comparison of different surgical techniques with regard to complete/incomplete closure success. More recently, PROTECT-AF long-term results (4-year follow-up) demonstrated that LAAC was statistically superior to warfarin in terms of efficacy. This review concludes that it is now appropriate to consider these techniques for patients with AF who are at high risk for stroke for whom effective conventional or novel anticoagulant therapy is not available or who present problems in managing drug treatment. Copyright © 2014 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

  15. 105-DR Large Sodium Fire Facility closure plan. Revision 1

    Energy Technology Data Exchange (ETDEWEB)


    The Hanford Site, located northwest of the city of Richland, Washington, houses reactors, chemical-separation systems, and related facilities used for the production of special nuclear materials, and activities associated with nuclear energy development. The 105-DR Large Sodium Fire Facility (LSFF), which was in operation from about 1972 to 1986, was a research laboratory that occupied the former ventilation supply room on the southwest side of the 105-DR Reactor facility. The LSFF was established to provide a means of investigating fire and safety aspects associated with large sodium or other metal alkali fires in the liquid metal fast breeder reactor (LMFBR) facilities. The 105-DR Reactor facility was designed and built in the 1950`s and is located in the 100-D Area of the Hanford Site. The building housed the 105-DR defense reactor, which was shut down in 1964. The LSFF was initially used only for engineering-scale alkali metal reaction studies. In addition, the Fusion Safety Support Studies program sponsored intermediate-size safety reaction tests in the LSFF with lithium and lithium lead compounds. The facility has also been used to store and treat alkali metal waste, therefore the LSFF is subject to the regulatory requirements for the storage and treatment of dangerous waste. Closure will be conducted pursuant to the requirements of the Washington Administrative Code (WAC) 173-303-610. This closure plan presents a description of the facility, the history of waste managed, and the procedures that will be followed to close the LSFF as an Alkali Metal Treatment Facility. No future use of the LSFF is expected.

  16. Effect of aerosol subgrid variability on aerosol optical depth and cloud condensation nuclei: Implications for global aerosol modelling

    NARCIS (Netherlands)

    Weigum, Natalie; Schutgens, Nick; Stier, Philip


    A fundamental limitation of grid-based models is their inability to resolve variability on scales smaller than a grid box. Past research has shown that significant aerosol variability exists on scales smaller than these grid-boxes, which can lead to discrepancies in simulated aerosol climate effects

  17. Multiple coil closure of isolated aortopulmonary collateral

    Directory of Open Access Journals (Sweden)

    Padhi Sumanta


    Full Text Available A 7-month-old girl was diagnosed to have large aortopulmonary collateral during evaluation for congestive heart failure. There was no other evidence of cardiopulmonary disease. The collateral was successfully closed with multiple coils delivered sequentially. We describe the issues associated during closure of the aortopulmonary collateral in this case. To the best of our knowledge, this is the first reported case of large aortopulmonary collateral presenting with heart failure in an otherwise structurally normal heart that was closed successfully with multiple coils delivered sequentially.

  18. Defense Base Closure and Realignment Commission (United States)


    34A (mnor)Organlizar ion, Kansas City vInformat ion (C) Trideni Refit Fdily a Rii vinos \\VAy. Ulinr PceinCnirNIt(inr Organizat ion , CIlevelianid...the Gulf of Mexico was questionable. The Naval Station Ingleside, Fleet Training Center community also stated the closure of the Naval Mayport, and...EvlainFacility, VI,10 01t(NkEAlljU:jlNeMexico, inl Crder_ to IrIOVItLe 1iaisonl with the Albuquerque, N~ew Mexico Sandia L~ahorator)’ Of the DvIlepariucrt

  19. Simple Case Treatment Planning: Diastema Closure. (United States)

    Calamia, Vincent; Pantzis, Alexandria


    This article demonstrates the use of a smile evaluation form as an adjunct in arriving at diagnosis and developing a treatment plan for a patient desiring Diastema closure. It also shows the importance of the diagnostic wax-up for temporization and visualization of case outcome. The case also demonstrates the use of soft tissue lasers to create a gingival harmony that enhanced the resulting esthetics. Feldspathic porcelain was used for the final restorations because they provide optimal esthetics and translucency. Copyright © 2015 Elsevier Inc. All rights reserved.

  20. Narrative Intelligibility and Closure in Interactive Systems

    DEFF Research Database (Denmark)

    Bruni, Luis Emilio; Baceviciute, Sarune


    ), which in turn can be seen as a function of Narrative Intelligibility. AAD can also be influenced by the intended or unintended level of abstractedness or didascalicity (i.e. figurativeness) of a given narrative. We define narrative intelligibility in complementarity with the related notion of Narrative...... Closure. We also make a distinction between the goals of the system and the goals of the narrative that it mediates, and consider the proposed parameters at two interrelated levels of analysis: the system level and the embedded narrative level, as the normative values and goals of these two levels should...

  1. 100-N Area underground storage tank closures

    Energy Technology Data Exchange (ETDEWEB)

    Rowley, C.A.


    This report describes the removal/characterization actions concerning underground storage tanks (UST) at the 100-N Area. Included are 105-N-LFT, 182-N-1-DT, 182-N-2-DT, 182-N-3-DT, 100-N-SS-27, and 100-N-SS-28. The text of this report gives a summary of remedial activities. In addition, correspondence relating to UST closures can be found in Appendix B. Appendix C contains copies of Unusual Occurrence Reports, and validated sampling data results comprise Appendix D.

  2. Post Closure Safety of the Morsleben Repository

    Energy Technology Data Exchange (ETDEWEB)

    Preuss, J.; Eilers, G.; Mauke, R.; Moeller-Hoeppe, N.; Engelhardt, H.-J.; Kreienmeyer, M.; Lerch, C.; Schrimpf, C.


    After the completion of detailed studies of the suitability the twin-mine Bartensleben-Marie, situated in the Federal State of Saxony-Anhalt (Germany), was chosen in 1970 for the disposal of low and medium level radioactive waste. The waste emplacement started in 1978 in rock cavities at the mine's fourth level, some 500 m below the surface. Until the end of the operational phase in 1998 in total about 36,800 m{sup 3} of radioactive waste was disposed of. The Morsleben LLW/ILW repository (ERAM) is now under licensing for closure. After completing the licensing procedure the repository will be sealed and backfilled to exclude any undue future impact onto man or the environment. The main safety objective is to protect the biosphere from the harmful effects of the disposed radionuclides. Furthermore, classical or conventional requirements call for ruling out or minimizing other unfavorable environmental effects. The ERAM is an abandoned rock salt and potash mine. As a consequence it has a big void volume, however small parts of the cavities are backfilled with crushed salt rocks. Other goals of the closure concept are therefore a long-term stabilization of the cavities to prevent a dipping or buckling of the ground surface. In addition, groundwater protection shall be assured. For the sealing of the repository a closure concept was developed to ensure compliance with the safety protection objectives. The concept anticipates the backfilling of the cavities with hydraulically setting backfill materials (salt concretes). The reduction of the remaining void volume in the mine causes in the case of brine intrusions a limitation of the leaching processes of the exposed potash seams. However, during the setting process the hydration heat of the concrete will lead to an increase of the temperature and hence to thermally induced stresses of the concrete and the surrounding rocks. Therefore, the influence of these stresses and deformations on the stability of the salt body

  3. U.S. Small Business HUBZone Base Closure Areas (United States)

    Small Business Administration — HUBZone Qualitified Base Closure Areas - the lands within the boundaries of a military installation that was closed through a privatization process under the Federal...

  4. Simulating school closure policies for cost effective pandemic decision making

    Directory of Open Access Journals (Sweden)

    Araz Ozgur M


    Full Text Available Abstract Background Around the globe, school closures were used sporadically to mitigate the 2009 H1N1 influenza pandemic. However, such closures can detrimentally impact economic and social life. Methods Here, we couple a decision analytic approach with a mathematical model of influenza transmission to estimate the impact of school closures in terms of epidemiological and cost effectiveness. Our method assumes that the transmissibility and the severity of the disease are uncertain, and evaluates several closure and reopening strategies that cover a range of thresholds in school-aged prevalence (SAP and closure durations. Results Assuming a willingness to pay per quality adjusted life-year (QALY threshold equal to the US per capita GDP ($46,000, we found that the cost effectiveness of these strategies is highly dependent on the severity and on a willingness to pay per QALY. For severe pandemics, the preferred strategy couples the earliest closure trigger (0.5% SAP with the longest duration closure (24 weeks considered. For milder pandemics, the preferred strategies also involve the earliest closure trigger, but are shorter duration (12 weeks for low transmission rates and variable length for high transmission rates. Conclusions These findings highlight the importance of obtaining early estimates of pandemic severity and provide guidance to public health decision-makers for effectively tailoring school closures strategies in response to a newly emergent influenza pandemic.

  5. Military Base Closures: Updated Status of Prior Base Realignments and Closures (United States)

    As the Department of Defense (DOD) prepares for the 2005 base realignment and closure (BRAC) round, questions continue to be raised about the transfer and environmental cleanup of unneeded property arising from the prior four BRAC rounds and their impact on cost and savings and on local economies.

  6. Collaborative Project: High-resolution Global Modeling of the Effects of Subgrid-Scale Clouds and Turbulence on Precipitating Cloud Systems

    Energy Technology Data Exchange (ETDEWEB)

    Randall, David A. [Colorado State Univ., Fort Collins, CO (United States). Dept. of Atmospheric Science


    We proposed to implement, test, and evaluate recently developed turbulence parameterizations, using a wide variety of methods and modeling frameworks together with observations including ARM data. We have successfully tested three different turbulence parameterizations in versions of the Community Atmosphere Model: CLUBB, SHOC, and IPHOC. All three produce significant improvements in the simulated climate. CLUBB will be used in CAM6, and also in ACME. SHOC is being tested in the NCEP forecast model. In addition, we have achieved a better understanding of the strengths and limitations of the PDF-based parameterizations of turbulence and convection.

  7. Evaluation of the Transport and Diffusion of Pollutants over an Urban Area Using a Local-Scale Advection-Diffusion Model and a Sub-Grid Street Model

    DEFF Research Database (Denmark)

    Salerno, R.; Vignati, E.


    Fifth International Conference on the Development and Application of Computer Techniques to Environmental Studies, Envirosoft/94.......Fifth International Conference on the Development and Application of Computer Techniques to Environmental Studies, Envirosoft/94....

  8. Final Technical Report for "High-resolution global modeling of the effects of subgrid-scale clouds and turbulence on precipitating cloud systems"

    Energy Technology Data Exchange (ETDEWEB)

    Larson, Vincent [Univ. of Wisconsin, Milwaukee, WI (United States)


    The Multiscale Modeling Framework (MMF) embeds a cloud-resolving model in each grid column of a General Circulation Model (GCM). A MMF model does not need to use a deep convective parameterization, and thereby dispenses with the uncertainties in such parameterizations. However, MMF models grossly under-resolve shallow boundary-layer clouds, and hence those clouds may still benefit from parameterization. In this grant, we successfully created a climate model that embeds a cloud parameterization (“CLUBB”) within a MMF model. This involved interfacing CLUBB’s clouds with microphysics and reducing computational cost. We have evaluated the resulting simulated clouds and precipitation with satellite observations. The chief benefit of the project is to provide a MMF model that has an improved representation of clouds and that provides improved simulations of precipitation.

  9. Risk factors for surgical site infection after stoma closure comparison between pursestring wound closure and conventional linear wound closure: Propensity score matching analysis. (United States)

    Yamamoto, Masashi; Tanaka, Keitaro; Masubuchi, Shinsuke; Ishii, Masatsugu; Hamamoto, Hiroki; Suzuki, Shigenori; Ueda, Yasuhiko; Okuda, Junji; Uchiyama, Kazuhisa


    Stoma closure has been associated with a high rate of surgical site infection (SSI) and the optimal skin closure method is still controversial. The aim of this study was to compare the short-term and long-term outcomes between the conventional linear closure (CC) and the persestring closure (PC) using propensity score matching analysis. We analysed the data of 360 patients who underwent stoma closure with CC or PC between January 2000 and December 2014. The propensity score was calculated from age, gender, body mass index, primary disease, type of stoma, diabetes mellitus, history of smoking, steroid use, the American Society of Anesthesiologists score, Prognostic Nutritional Index and modified Glasgow Prognostic Score. There was no difference in operative variables between the two groups. The CC group and the PC group were comparable with regards to overall SSI (25.0 vs. 7.8%; P = 0.007), superficial SSI (21.9 vs. 4.7%; P = 0.003). Significant risk factor for SSI was conventional linear closure (OR, 4.14; 95% CI, 1.448-13.91). Our study suggests that a pursestring stoma closure leads to less SSI. Copyright © 2017 Elsevier Inc. All rights reserved.

  10. Tacks, staples, or suture: method of peritoneal closure in laparoscopic transabdominal preperitoneal inguinal hernia repair effects early quality of life. (United States)

    Ross, Samuel W; Oommen, Bindhu; Kim, Mimi; Walters, Amanda L; Augenstein, Vedra A; Heniford, B Todd; Todd Heniford, B


    TAPP inguinal hernia repair (IHR) entails the development of a peritoneal flap (PF) in order to reduce the hernia sac and create a preperitoneal space in which to place mesh. Many methods for closure of the PF exist including sutures, tacks, and staples. We hypothesized that patients who had PF closure with suture would have better short-term QOL outcomes. A prospective institutional hernia-specific database was queried for all adult, TAPP IHRs from July 2012 to August 2013. Unilateral and bilateral patients were included and each hernia was analyzed separately. The main outcome of interest was quality of life (QOL) at two- and four-week follow-up, as measured by the Carolinas Comfort Scale. There were 227 patients who underwent TAPP, with 99 bilateral and 128 unilateral IHR, for a total of 326 IHR. PF closure was performed using tacks in 45.1%, suture in 19.0%, and staples in 35.9%. Patient characteristics were statistically similar between the tack, suture, and staple group. There were 32.9% direct, 46.5% indirect, and 20.6% pantaloon hernias, which were not significantly different when compared by PF closure method. Post-operative complications and length of stay were same for the three groups. There were no hernia recurrences. Post-operative activity limitation at two weeks was significantly better in the suture group when compared to the stapled group (p = 0.005). Additionally, sutured PF closure had less early post-operative pain when compared to the tack group (p = 0.038). Following TAPP IHR, suture closure of the PF significantly improves 2-week post-operative movement limitation compared to stapled and tacked PF closure. Continued randomized studies are needed to determine the best surgical hernia repair methods for ideal post-op QOL.

  11. Impact of Different Standard Type A7A Drum Closure-Ring Practices on Gasket Contraction and Bolt Closure Distance– 15621

    Energy Technology Data Exchange (ETDEWEB)

    Ketusky, Edward [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Blanton, Paul [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Bobbitt, John H. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)


    The Department of Energy, the Savannah River National Laboratory, several manufacturers of specification drums, and the United States Department of Transportation (DOT) are collaborating in the development of a guidance document for DOE contractors and vendors who wish to qualify containers to DOT 7A Type A requirements. Currently, the effort is focused on DOT 7A Type A 208-liter (55-gallons) drums with a standard 12-gauge bolted closure ring. The U.S. requirements, contained in Title 49, Part 178.350 “Specification 7A; general packaging, Type A specifies a competent authority review of the packaging is not required for the transport of (Class 7) radioactive material containing less than Type A quantities of radioactive material. For Type AF drums, a 4 ft. regulatory free drop must be performed, such that the drum “suffers maximum damage.” Although the actual orientation is not defined by the specification, recent studies suggest that maximum damage would result from a shallow angle top impact, where kinetic energy is transferred to the lid, ultimately causing heavy damage to the lid, or even worse, causing the lid to come off. Since each vendor develops closure recommendations/procedures for the drums they manufacture, key parameters applied to drums during closing vary based on vendor. As part of the initial phase of the collaboration, the impact of the closure variants on the ability of the drum to suffer maximum damage is investigated. Specifically, closure testing is performed varying: 1) the amount of torque applied to the closure ring bolt; and, 2) stress relief protocol, including: a) weight of hammer; and, b) orientation that the hammer hits the closure ring. After closure, the amount of drum lid gasket contraction and the distance that the closure bolt moves through the closure ring is measured.

  12. SRS tank closure. Innovative technology summary report

    Energy Technology Data Exchange (ETDEWEB)


    High-level waste (HLW) tank closure technology is designed to stabilize any remaining radionuclides and hazardous constituents left in a tank after bulk waste removal. Two Savannah River Site (SRS) HLW tanks were closed after cleansing and then filling each tank with three layers of grout. The first layer consists of a chemically reducing grout. The fill material has chemical properties that retard the movement of some radionuclides and chemical constituents. A layer of controlled low-strength material (CLSM), a self-leveling fill material, is placed on top of the reducing grout. CLSM provides sufficient strength to support the overbearing weight. The final layer is a free-flowing, strong grout similar to normal concrete. After the main tank cavity is filled, risers are filled with grout, and all waste transfer piping connected to the tank is isolated. The tank ventilation system is dismantled, and the remaining systems are isolated. Equipment that remains with the tank is filled with grout. The tank and ancillary systems are left in a state requiring only limited surveillance. Administrative procedures are in place to control land use and access. DOE eventually plans to remove all of its HLW storage tanks from service. These tanks are located at SRS, Hanford, and Idaho National Engineering and Environmental Laboratory. Low-activity waste storage tanks at Oak Ridge Reservation are also scheduled for closure.

  13. Vascular Closure Devices in Interventional Radiology Practice

    Energy Technology Data Exchange (ETDEWEB)

    Patel, Rafiuddin, E-mail: [John Radcliffe Hospital, Department of Radiology (United Kingdom); Muller-Hulsbeck, Stefan, E-mail: [Diakonissen Hospital, Diagnostic and Interventional Radiology/Neuroradiology (Germany); Morgan, Robert, E-mail: [St George’s Hospital, Department of Radiology (United Kingdom); Uberoi, Raman, E-mail: [John Radcliffe Hospital, Department of Radiology (United Kingdom)


    Manual compression (MC) is a well-established technique for haemostasis following percutaneous arterial intervention. However, MC is labour and time intensive with potential limitations, particularly for patients who are coagulopathic, unable to comply with bed rest or obese and when large sheaths or anti-coagulants are used. There are a variety of vascular closure devices (VCDs) available to overcome these limitations. This review gives an overview of current VCDs, their mechanism of action, individual strengths and weaknesses, evidence base and utility in interventional radiology (IR) practice. The majority of the published evidence on VCDs is derived from patients undergoing cardiac interventions, which should be borne in mind when considering the applicability and transfer of this data for general IR practice. Overall, the evidence suggests that most VCDs are effective in achieving haemostasis with a similar rate of complications to MC although the complication profile associated with VCDs is distinct to that of MC. There is insufficient evidence to comparatively analyse the different types of VCDs currently available or reliably judge their cost-effectiveness. The interventional radiologist should have a thorough understanding of the available techniques for haemostasis and be able to identify and utilise the most appropriate strategy and closure technique for the individual patient.


    CERN Multimedia


    Mail, NICE 2000, Web, EDMS (in collaboration with EST Division), General purpose databases, lxbatch, lxplus, Automated tape devices, Castor, Backups, Campus Network, Remedy, Security and VPN services will be available during the CERN annual closure. Problems developing on these services should be addressed within about half a day except on Christmas and New Year evenings, December 25, 2002 and January 1st, 2003. All other services will be left running mostly unattended. No interruptions are scheduled but restoration of the service in case of failure cannot be guaranteed. It should be noted that the Helpdesk will be closed, that no file restores from backups will be possible and damaged tapes will not be processed. An operator service will be maintained and can be reached at extension 75011 or by email to Please remember to shutdown and power off any equipment in your office which is not foreseen to be used during the annual closure before you leave for the holiday.

  15. Thesaurus Building With Transitive Closures For Kadre (United States)

    Biswas, Gautam; Bezdek, J. C.; Huang, Li-ya


    Currently there is a big thrust towards the development of automated, user-friendly online information retrieval systems, which are software packages that allow a user population to query and receive appropriate information that is stored in a computer data-base. Our research adopts a knowledge based approach to the design and development of KADRE (Knowledge Assisted Document Retrieval Expert), an experimental online document retrieval system. Knowledge based techniques allow us to incorporate some of an expert librarian's heuristic techniques into the retrieval process. We present the mathematical model of the retrieval system as a five step process and discuss the system thesaurus in some detail. Six different transitive closures of the relational matrix of term pairs are used to compute the thesaurus, and the retrieval output produced by these techniques are compared. Representation of the thesaurus as a transitive closure offers two very significant advan-tages: this method provides a means for completion of partial knowledge which is represented as numerical relational data; and the ensuing completion has a well defined property of (mathemati-cal) consistency.


    Energy Technology Data Exchange (ETDEWEB)

    Daugherty, W.; Howard, S.; Peterson, K.; Stokes, M.


    Excess plutonium materials in the DOE complex are packaged and stored in accordance with DOE-STD-3013. This standard specifies requirements for the stabilization of such materials and subsequent packaging in dual nested seal-welded containers. Austenitic stainless steels have been selected for container fabrication. The inner 3013 container provides contamination control while the outer 3013 container is the primary containment vessel and is the focus of this paper. Each packaging site chose a process for seal welding the outer 3013 containers in accordance with its needs and expertise. The two processes chosen for weld closure were laser beam welding (LBW) and gas tungsten arc welding (GTAW). Following development efforts, each system was qualified in accordance with DOE-STD-3013 prior to production use. The 3013 outer container closure weld joint was designed to accommodate the characteristics of a laser weld. This aspect of the joint design necessitated some innovative process and equipment considerations in the application of the GTAW process. Details of the weld requirements and the development processes are presented and several potential enhancements for the GTAW system are described.

  17. Multiscale spatial Monte Carlo simulations: multigriding, computational singular perturbation, and hierarchical stochastic closures. (United States)

    Chatterjee, Abhijit; Vlachos, Dionisios G


    Monte Carlo (MC) simulation of most spatially distributed systems is plagued by several problems, namely, execution of one process at a time, large separation of time scales of various processes, and large length scales. Recently, a coarse-grained Monte Carlo (CGMC) method was introduced that can capture large length scales at reasonable computational times. An inherent assumption in this CGMC method revolves around a mean-field closure invoked in each coarse cell that is inaccurate for short-ranged interactions. Two new approaches are explored to improve upon this closure. The first employs the local quasichemical approximation, which is applicable to first nearest-neighbor interactions. The second, termed multiscale CGMC method, employs singular perturbation ideas on multiple grids to capture the entire cluster probability distribution function via short microscopic MC simulations on small, fine-grid lattices by taking advantage of the time scale separation of multiple processes. Computational strategies for coupling the fast process at small length scales (fine grid) with the slow processes at large length scales (coarse grid) are discussed. Finally, the binomial tau-leap method is combined with the multiscale CGMC method to execute multiple processes over the entire lattice and provide additional computational acceleration. Numerical simulations demonstrate that in the presence of fast diffusion and slow adsorption and desorption processes the two new approaches provide more accurate solutions in comparison to the previously introduced CGMC method.

  18. Resident-performed laser peripheral iridotomy in primary angle closure, primary angle closure suspects, and primary angle closure glaucoma

    Directory of Open Access Journals (Sweden)

    Kam JP


    Full Text Available Jason P Kam, Emily M Zepeda, Leona Ding, Joanne C Wen Department of Ophthalmology, University of Washington, Seattle, WA, USA Purpose: To investigate the power use and complication frequency of resident-performed laser peripheral iridotomy (LPI.Methods: A retrospective analysis of 196 eyes from 103 patients who underwent neodymium: yttrium-aluminum-garnet laser iridotomy performed by resident physicians from January 1, 2010 through April 30, 2015 at a university-based county hospital was done. All patients were treated for primary angle closure, primary angle closure suspects, and primary angle closure glaucoma. Data were collected on pre- and post-laser intraocular pressure (IOP, ethnicity, laser parameters and complications. Mean power use and frequency of complications were evaluated. Complications included elevated post-laser IOP at 30–45 minutes (≥8 mmHg, hyphema, aborted procedures, and lasering non-iris structures. The number of repeated LPI procedures, was also recorded.Results: Mean total power used for all residents was 78.2±68.7 mJ per eye. Power use by first-year trainees was significantly higher than second- and third-year trainees (103.5±75.5 mJ versus 73.7±73.8 mJ and 67.2±56.4 mJ, respectively, p=0.011. Complications included hyphema or microhyphema in 17.9% (35/196, IOP spikes in 5.1% (10/196, aborted procedures in 1.1% (3/196 and lasering non-iris structures in 0.5% (1/196. LPI was repeated in 22.4% of cases (44/196 with higher incidence of repeat LPI among non-Caucasian compared to the Caucasian subjects (p=0.02. Complication rates did not differ with increased training (p=0.16.Conclusion: Total power used for LPI decreased with increased resident training, while the complication rate did not differ significantly among resident classes. Complication rates were comparable to rates reported in the literature for attending-performed LPIs. Keywords: laser, iridotomy, resident, complications, power, energy

  19. A hierarchy of energy- and flux-budget (EFB) turbulence closure models for stably stratified geophysical flows

    CERN Document Server

    Zilitinkevich, S S; Kleeorin, N; Rogachevskii, I; Esau, I


    In this paper we advance physical background of the EFB turbulence closure and present its comprehensive description. It is based on four budget equations for the second moments: turbulent kinetic and potential energies (TKE and TPE) and vertical turbulent fluxes of momentum and buoyancy; a new relaxation equation for the turbulent dissipation time-scale; and advanced concept of the inter-component exchange of TKE. The EFB closure is designed for stratified, rotating geophysical flows from neutral to very stable. In accordance to modern experimental evidence, it grants maintaining turbulence by the velocity shear at any gradient Richardson number Ri, and distinguishes between the two principally different regimes: "strong turbulence" at Ri 1 typical of the free atmosphere or deep ocean, where Pr_T asymptotically linearly increases with increasing Ri that implies strong suppressing of the heat transfer compared to momentum transfer. For use in different applications, the EFB turbulence closure is formulated a...

  20. Patient Satisfaction After Femoral Arterial Access Site Closure Using the ExoSeal{sup ®} Vascular Closure Device Compared to Manual Compression: A Prospective Intra-individual Comparative Study

    Energy Technology Data Exchange (ETDEWEB)

    Pieper, Claus Christian, E-mail:; Thomas, Daniel, E-mail: [University of Bonn, Department of Radiology (Germany); Nadal, Jennifer, E-mail: [University of Bonn, Institute for Medical Biometry, Informatics and Epidemiology (Germany); Willinek, Winfried A., E-mail:; Schild, Hans Heinz, E-mail:; Meyer, Carsten, E-mail: [University of Bonn, Department of Radiology (Germany)


    PurposeTo intra-individually compare discomfort levels and patient satisfaction after arterial access closure using the ExoSeal{sup ®} vascular closure device (VCD) and manual compression (MC) in a prospective study design.MethodsPatients undergoing two planned interventions from 07/2013 to 09/2014 could participate in the study. Access closure was performed with an ExoSeal{sup ®}-VCD in one and MC in the other intervention. Patients were clinically and sonographically examined and were given questionnaires 1 day after intervention [groin- and back-pain during bedrest (100-point visual analog scale; 0: no pain); comfortability of bedrest (10-point Likert scale, 1: comfortable), satisfaction with closure (10-point Likert scale, 1: very satisfied)]. Results were analyzed in a cross-over design.Results48 patients (29 male, median age 62.5 (32–88) years) were included. An ExoSeal{sup ®}-VCD was used first in 25 cases. As four of these subsequently refused MC as second intervention, data from 44 patients could be analyzed. All closures were technically successful (successful device deployment) without major complications. Groin- and back-pain after VCD-use/MC was 0 (0–15) vs. 10 (0–80) and 0 (0–75) vs. 25 (0–90), respectively (p < 0.0001). Bedrest after VCD-use was more comfortable than after MC [1 (range 1–7) vs. 6 (2–10); p < 0.0001]. Satisfaction with the closure procedure and with the intervention in general was higher after VCD-use compared to MC [1 (1–3) vs. 5 (2–10) and 1 (1–2) vs. 2 (1–4), respectively; p < 0.0001].ConclusionIntra-individual comparison showed pain levels and discomfort to be significantly lower after ExoSeal{sup ®} use compared to MC. VCD closure was associated with higher satisfaction both with the closure itself and with the intervention in general.

  1. The impact of phonation mode and vocal technique on vocal fold closure in young females with normal voice quality. (United States)

    De Bodt, Marc S; Clement, Gregory; Wuyts, Floris L; Borghs, Cindy; Van Lierde, Kristiane M


    Because voice quality depends substantially on vocal fold closure (VFC), voice therapists try to modify VFC by specific voice techniques or adjustments in phonation mode. This study demonstrates the impact of six different phonation modes on VFC in healthy subjects. For this study, 21 female subjects with normal voice quality were selected. The impact of different phonation modes and voice techniques was examined by fiberoptic laryngovideoendoscopy during different modes of phonation: habitual phonation, high pitch, low pitch, resonance on /m/, Coblenzer's "abspannen," and chant talk. The video recordings were judged by three experienced professionals (two Speech and Language Pathologist and one laryngologist) by means of a visual analog scale. Statistical analysis showed that only resonance on /m/ significantly improved VFC compared with habitual phonation. All other phonation modes and techniques, except low-pitched phonation, led to a significant worse closure in comparison with the closure at normal pitch. The glottic closure observed by low-pitched phonation was not significantly different than the closure at habitual pitch. Interrater agreement was moderate to very good, depending on the mode of phonation. The results of this study allow a better understanding of the impact of phonation mode and vocal therapy techniques on VFC in healthy subjects and give an indication about the impact of these methods to influence VFC. Copyright © 2012 The Voice Foundation. Published by Mosby, Inc. All rights reserved.

  2. Guinea pig ductus arteriosus. II - Irreversible closure after birth. (United States)

    Fay, F. S.; Cooke, P. H.


    To investigate the mechanism underlying irreversibility of ductal closure after birth, studies were undertaken to determine the exact time course for the onset of irreversible closure of the guinea pig ductus arteriosus. Parallel studies of the reactivity of ductal smooth muscle to oxygen and studies of the postpartum cellular changes within the vessel were also carried out.

  3. On the normality of orbit closures which are hypersurfaces

    Indian Academy of Sciences (India)

    quiver representations). It is an interesting task to study geometric properties of the Zariski closures – being affine varieties – of GL(d)-orbits in repQ(d), as well as their connections with representation-theoretic properties of the quiver Q and its representations. Among the geometric properties of orbit closures that have ...

  4. On the normality of orbit closures which are hypersurfaces

    Indian Academy of Sciences (India)

    Let be a quiver representation with non-zero admissible annihilator. In this paper, we prove the normality of the orbit closure O ¯ N when it is a hypersurface. The result thus gives new examples of normal orbit closures of quiver representations.

  5. A Simple Technique for Safe Mesenteric Defect Closure Following ...

    African Journals Online (AJOL)

    laparoscopic-assisted sigmoid colectomy. JSLS 1999;3:79-81. 6. Causey MW, Oguntoye M, Steele SR. Incidence of complications following colectomy with mesenteric closure versus no mesenteric closure: Does it really matter? J Surg Res 2011;171:571-5. 7. Cabot JC, Lee SA, Yoo J, Nasar A, Whelan RL, Feingold DL.

  6. Which Patent Foramen Ovales Need Closure to Prevent Cryptogenic Strokes? (United States)

    Dalen, James E; Alpert, Joseph S


    Patients with cryptogenic strokes are more likely to have a patent foremen ovale than in the general population. It is speculated that these strokes are due to paradoxical embolism, that is, passage of a venous thrombus across the patent foremen ovale to enter the arterial circulation, resulting in an embolic stroke. Venous thromboembolism is rarely present in these cases of cryptogenic stroke. Thousands of patients with cryptogenic strokes have undergone transcatheter closure of their patent foremen ovale via a variety of devices. The first 3 randomized clinical trials comparing patent foremen ovale closure with medical therapy failed to show a significant advantage of patent foremen ovale closure. Three additional trials reported in 2017 had longer years of follow-up and demonstrated an advantage of patent foremen ovale closure versus medical therapy. Analysis of their data indicated that patent foremen ovale closure in patients with an atrial septal aneurysm in addition to a patent foremen ovale had a very significant decrease in cryptogenic strokes (P patent foremen ovale closure (P = .37). Aneurysms of the atrial septum are easily recognized by echocardiography and are present in approximately one-third of patients with patent foremen ovales. These data suggest that closure of patent foremen ovales in patients with an atrial septal aneurysm is indicated. In patients with a patent foremen ovale without an aneurysm of the atrial septum, patent foremen ovale closure is not indicated. Copyright © 2018 Elsevier Inc. All rights reserved.

  7. Patent Foramen Ovale Closure or Antiplatelet Therapy for Cryptogenic Stroke

    DEFF Research Database (Denmark)

    Søndergaard, Lars; Kasner, Scott E; Rhodes, John F


    BACKGROUND: The efficacy of closure of a patent foramen ovale (PFO) in the prevention of recurrent stroke after cryptogenic stroke is uncertain. We investigated the effect of PFO closure combined with antiplatelet therapy versus antiplatelet therapy alone on the risks of recurrent stroke and new...

  8. Surgical Experience with Closure of an Isolated PDA at Muhimbili ...

    African Journals Online (AJOL)

    Background: This study describes our experience in the management of isolated patent ductus arteriosus; complications and mortality rate. Further it describes the innovative technique for the closure of the duct. Methods: We retrospectively recruited all patients' files that underwent PDA closure from May 2008 to July 2011 ...

  9. Localization of tight closure in two-dimensional rings

    Indian Academy of Sciences (India)

    R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

    localization in a general situation. There are some related conjectures that a positive answer to each of them will yield solution to the localization problem. For example, it is an open question that for any ideal I of a domain R, I∗ = IR+ ∩ R, where R+ denote the integral closure of R in an algebraic closure of its fraction field.

  10. The Impact of Mine Closures on Rural Population Dynamics: The ...

    African Journals Online (AJOL)

    The paper examines the demographic and socio-cultural impact of spontaneous population inflows into Zhombe following the closure of the Empress Mine in 1982. Data was collected using a questionnaire survey. Results of the study show that mine closures cause rural population change. The population directly grows ...

  11. 40 CFR 265.112 - Closure plan; amendment of plan. (United States)


    ... contaminated soils, methods for sampling and testing surrounding soils, and criteria for determining the extent... partial and final closure. (For example, in the case of a landfill unit, estimates of the time required to... all hazardous wastes at closure, but are required to close as landfills in accordance with § 265.310...

  12. Morbidity of Colostomy Closure in Children | Nasir | African Journal ...

    African Journals Online (AJOL)

    The care of colostomy remains a burden to the family while complications associated with its construction and closure can be tasking to the surgeon. The aim of this study was to evaluate the outcome of colostomy closure in children in our setting. A prospective review of 31 consecutive children undergoing colostomy ...

  13. 21 CFR 211.94 - Drug product containers and closures. (United States)


    ... 21 Food and Drugs 4 2010-04-01 2010-04-01 false Drug product containers and closures. 211.94 Section 211.94 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... and closures shall be clean and, where indicated by the nature of the drug, sterilized and processed...

  14. 77 FR 55895 - Permanent Closure of Cincinnati Blue Ash Airport (United States)


    ... Federal Aviation Administration Permanent Closure of Cincinnati Blue Ash Airport AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Notice of permanent closure of Cincinnati Blue Ash Airport (ISZ). SUMMARY: The... Cincinnati advising that on August 29, 2012, it was permanently closing Cincinnati Blue Ash Airport (ISZ...

  15. Vacuum-assisted closure for defects of the abdominal wall. (United States)

    DeFranzo, Anthony J; Pitzer, Keith; Molnar, Joseph A; Marks, Malcolm W; Chang, Michael C; Miller, Preston R; Letton, Robert W; Argenta, Louis C


    Reconstruction of the abdominal wall poses a problem common to many surgical specialties. Abdominal wall defects may be caused by trauma and/or prior surgery, with dehiscence or infection. Several options to repair the structural integrity of the abdominal wall exist, including primary closure, flaps, mesh, and skin grafts. Complications of these procedures include recurrent infection of the abdominal wall, infection of mesh, dehiscence, flap death, and poor skin graft take. Risk factors predisposing to these complications include tissue edema, preoperative tissue infection, and patient debilitation, with poor wound healing potential. Ideally, reconstruction should be performed on a nonedematous, clean tissue bed with bacterial levels less than 10 bacteria/cm in a well-nourished patient. Vacuum-assisted closure was used in a series of patients in an attempt to prepare the abdominal wall for reconstruction and reduce the risk of complications. Charts were reviewed for 100 patients who underwent abdominal wall reconstruction after vacuum-assisted closure therapy. Their wound cause, reconstruction technique, complications, and number of days on the vacuum-assisted closure device are reported. The ability of vacuum-assisted closure to reduce edema, increase blood flow, potentially decrease bacterial colonization, and reduce wound size greatly facilitated abdominal wall reconstruction. The vacuum-assisted closure device served as a temporary dressing with which to control dehiscence and to maintain abdominal wall integrity when bowel wall edema prevented abdominal closure. Vacuum-assisted closure therapy frequently shortened time to abdominal wall reconstruction and simplified the method of reconstruction.

  16. Vacuum-Assisted Abdominal Closure Is Safe and Effective

    DEFF Research Database (Denmark)

    Jensen, R O; Buchbjerg, T; Simonsen, R M


    with median 1 (0-16) dressing changes. Seventy per cent of the patients attended the intensive care unit. The 90-day mortality was 15%. A secondary closure of the fascia was obtained in 84% of the surviving patients. Only one patient developed an enteroatmospheric fistula. Patients with secondary closure were...

  17. Management of open abdomen with an absorbable mesh closure. (United States)

    Prichayudh, Supparerk; Sriussadaporn, Suvit; Samorn, Pasurachate; Pak-Art, Rattaplee; Sriussadaporn, Sukanya; Kritayakirana, Kritaya; Capin, Allan


    To examine the methods and results of treatment in patients with an open abdomen (OA) at a single institution where an absorbable mesh closure (AMC) is most commonly used. A retrospective study was performed in OA patients from January 2001 to June 2007. Outcomes were analyzed in terms of enteroatmospheric fistula (EAF) formation and survival. There were 73 OA patients receiving definitive closures (40 trauma and 33 nontrauma). Twenty-four patients were able to undergo a delayed primary fascial closure (DPFC) after initial vacuum pack closure (DPFC rate 33%). The DPFC rate was significantly lower in patients with an associated infection or contamination (9% vs 44%, P = 0.002). The EAF and mortality rates of the DPFC group were 0% and 13%, respectively. Absorbable mesh closure was used in 41 of 49 patients who failed DPFC (84%). There were 9 patients who had EAF (overall EAF rate 12%), 6 of whom were in the AMC group (EAF rate 15%). The overall and AMC group mortality rates were 29% and 37%, respectively. Absorbable mesh closure carries high EAF and mortality rates. Therefore, DPFC should be considered as the primary closure method. Absorbable mesh closure should be reserved for patients who fail DPFC, especially those with peritonitis or contamination.

  18. On the fixed point of the iterated pseudopalindromic closure


    Jamet, D.; Paquin, G.; Richomme, G.; Vuillon, L.


    First introduced in the study of the Sturmian words, the iterated palindromic closure was recently generalized to pseudopalindromes. This operator allows one to construct words with an infinity of pseudopalindromic prefixes, called pseudostandard words. We provide here several combinatorial properties of the fixed points under the iterated pseudopalindromic closure.

  19. Outcome of primary closure of abdominal wounds following typhoid ...

    African Journals Online (AJOL)

    Background: Abdominal wounds following surgery for typhoid perforation are classifi ed as dirty, with an infection rate of over 40%. To date, the optimal method for closure of these wounds remains controversial. Delayed primary closure which was conventionally recommended as standard practice, is now considered to be ...

  20. Object grasping by combining caging and force closure

    NARCIS (Netherlands)

    Lei, Q.; Wisse, M.


    The current research trends of object grasping can be summarized as caging grasping and force closure grasping. The motivation of this paper is to combine the advantage of caging grasping and force closure grasping to enable under-actuated grippers like the Lacquey gripper and the parallel

  1. Brassinosteroids modulate ABA-induced stomatal closure in Arabidopsis. (United States)

    Ha, Yunmi; Shang, Yun; Nam, Kyoung Hee


    Stomatal movement in response to water availability is an important physiological process in the survival of land plants. The plant hormone abscisic acid (ABA) and brassinosteroids (BRs) regulate stomatal closure. The physiological functions of ABA and BRs, including germination, cell elongation and stomatal movement, are generally known to be antagonistic. Here, we investigated how BRs affect stomatal movement alone and in combination with ABA. We demonstrate that brassinoslide (BL), the most active BR, promotes stomatal closure in an ABA-independent manner. Interestingly, BL also inhibited ABA-induced stomatal closure when a high concentration of BL was added to ABA. Furthermore, we found that the induction of some genes for reactive oxygen species (ROS) generation by ABA (AtrbohD, NIA1 and NIA2) and subsequent ROS production were repressed by BL treatment. The BR signaling mutant bri1-301 failed to inhibit ABA-induced stomatal closure upon BL treatment. However, BRI1-overexpressing transgenic plants were hypersensitive to ABA during stomatal closure, and BL reversed ABA-induced stomatal closure more completely than in wild type plants. Taken together, these results suggest that BRs can positively and negatively modulate ABA-induced stomatal closure. Therefore, interactions between ABA and BR signaling are important for the regulation of stomatal closure. © The Author 2016. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  2. Single-site neural tube closure in human embryos revisited. (United States)

    de Bakker, Bernadette S; Driessen, Stan; Boukens, Bastiaan J D; van den Hoff, Maurice J B; Oostra, Roelof-Jan


    Since the multi-site closure theory was first proposed in 1991 as explanation for the preferential localizations of neural tube defects, the closure of the neural tube has been debated. Although the multi-site closure theory is much cited in clinical literature, single-site closure is most apparent in literature concerning embryology. Inspired by Victor Hamburgers (1900-2001) statement that "our real teacher has been and still is the embryo, who is, incidentally, the only teacher who is always right", we decided to critically review both theories of neural tube closure. To verify the theories of closure, we studied serial histological sections of 10 mouse embryos between 8.5 and 9.5 days of gestation and 18 human embryos of the Carnegie collection between Carnegie stage 9 (19-21 days) and 13 (28-32 days). Neural tube closure was histologically defined by the neuroepithelial remodeling of the two adjoining neural fold tips in the midline. We did not observe multiple fusion sites in neither mouse nor human embryos. A meta-analysis of case reports on neural tube defects showed that defects can occur at any level of the neural axis. Our data indicate that the human neural tube fuses at a single site and, therefore, we propose to reinstate the single-site closure theory for neural tube closure. We showed that neural tube defects are not restricted to a specific location, thereby refuting the reasoning underlying the multi-site closure theory. Clin. Anat. 30:988-999, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  3. Spontaneous closure of midline diastema following frenectomy. (United States)

    Koora, Kiran; Muthu, M S; Rathna, Prabhu V


    Maxillary midline diastema is a common aesthetic problem in mixed and early permanent dentitions. The space can occur either as a transient malocclusion or created by developmental, pathological or iatrogenical factors. Many innovative therapies varying from restorative procedures such as composite build-up to surgery (frenectomies) and orthodontics are available. Although literature says every frenectomy procedure should be preceded by orthodontic treatment, we opted for frenectomy technique without any orthodontic intervention. Presented herewith is a case report of a 9-year-old girl with a high frenal attachment that had caused spacing of the maxillary central incisors. A spontaneous closure of the midline diastema was noted within 2 months following frenectomy. The patient was followed up for 4 months after which the space remained closed and there was no necessity for an orthodontic treatment at a later stage.

  4. Spontaneous closure of midline diastema following frenectomy

    Directory of Open Access Journals (Sweden)

    Koora Kiran


    Full Text Available Maxillary midline diastema is a common aesthetic problem in mixed and early permanent dentitions. The space can occur either as a transient malocclusion or created by developmental, pathological or iatrogenical factors. Many innovative therapies varying from restorative procedures such as composite build-up to surgery (frenectomies and orthodontics are available. Although literature says every frenectomy procedure should be preceded by orthodontic treatment, we opted for frenectomy technique without any orthodontic intervention. Presented herewith is a case report of a 9-year-old girl with a high frenal attachment that had caused spacing of the maxillary central incisors. A spontaneous closure of the midline diastema was noted within 2 months following frenectomy. The patient was followed up for 4 months after which the space remained closed and there was no necessity for an orthodontic treatment at a later stage.

  5. The tibial bayonet method of wound closure. (United States)

    O'Farrell, Peter; Barnard, Annette-Christi; Birkholtz, Franz


    Management of open lower limb fractures with soft tissue defects can be a technically challenging orthopaedic problem. Limited availability of orthoplastic services means that alternatives to the fix and flap concept are required in order to prevent infected non-unions from developing. The proposed 'bayonet apposition' allows the surgeon to temporarily shorten the limb without angulating the limb or creating a bone defect and removing viable bone. The viable bone edges are overlapped in a bayonet-like manner in order to appose the wound and skin edges. The limb length is restored by gradually distracting the bone segments once the soft tissues have healed. This is facilitated with a hexapod fixator for stabilization of the fracture and distraction. Prerequisites for utilizing this method are circumferential soft tissue damage to the lower limb with viable distal tissue. The bayonet method allows primary closure of a wound and rapid restoration of the native length of the limb.

  6. Occupational closure in nursing work reconsidered

    DEFF Research Database (Denmark)

    Traynor, Michael; Nissen, Nina; Lincoln, Carol


    In healthcare, occupational groups have adopted tactics to maintain autonomy and control over their areas of work. Witz described a credentialist approach to occupational closure adopted by nursing in the United Kingdom during the 19th and early 20th centuries. However, the recent advancement...... boundaries and a usurpatory stance towards these boundaries. Participants had usually been handpicked by managers and some were ambitious and confident in their abilities. Many aspired to train to be nurses claiming that they will gain recognition that they do not currently get but which they deserve....... Their scope of practice is based upon their managers' or supervisors' perception of their individual aptitude rather than on a credentialist claim. They 'usurp' nurses claim to be the healthcare worker with privileged access to patients, saying they have taken over what nursing has considered its core work...

  7. Frictionless segmented mechanics for controlled space closure

    Directory of Open Access Journals (Sweden)

    Ildeu Andrade Jr

    Full Text Available ABSTRACT Extraction spaces may be needed to achieve specific orthodontic goals of positioning the dentition in harmony with the craniofacial complex. However, the fundamental reality that determines the occlusion final position is the control exerted by the orthodontist while closing the extraction spaces. A specific treatment objective may require the posterior teeth to remain in a constant position anteroposteriorly as well as vertically, while the anterior teeth occupy the entire extraction site. Another treatment objective may require the opposite, or any number of intentional alternatives of extraction site closure. The present case report describes a simple controlled segmented mechanic system that permitted definable and predictable force systems to be applied and allowed to predict the treatment outcome with confidence. This case was presented to the Brazilian Board of Orthodontics and Dentofacial Orthopedics (BBO in partial fulfillment of the requirements for Diplomate certification.

  8. A comparison of a new skin closure device and intradermal sutures in the closure of full-thickness surgical incisions. (United States)

    Richter, Dirk; Stoff, Alexander; Ramakrishnan, Venkat; Exner, Klaus; Jernbeck, Jan; Blondeel, Phillip N


    A novel topical skin adhesive system was developed to close the outermost layer of skin in an expeditious manner. To determine its clinical utility, a clinical investigation was undertaken to demonstrate equivalence of a new adhesive skin closure system (Prineo Skin Closure System) to intradermal sutures in wound closure. The investigation included 83 patients who underwent elective abdominoplasty, circumferential body lift procedures, and breast reconstruction with deep inferior epigastric perforator flaps. Incisions were divided in half, and each half was randomized to wound closure with the new skin closure system, including a pressure-sensitive adhesive mesh tape for wound edge approximation and next-generation cyanoacrylate or intradermal sutures. Postoperative evaluations took place at 24 hours, 7 days, 12 to 25 days, 90 days, 6 months, and 12 months. The new skin closure system was found to be equivalent to intradermal sutures for the continuous approximation of wounds. The upper limit of the two-sided 90 percent confidence interval for difference in proportions was 10.9 percent. The mean time to closure for the new skin closure system was 1.46 minutes, approximately 5 minutes faster than that for intradermal sutures (p sutures for full-thickness surgical incisions with regard to safety and effectiveness. The ease and speed of application contribute to shortened operative times (4.5 times faster than intradermal sutures).

  9. ICPP tank farm closure study. Volume 1

    Energy Technology Data Exchange (ETDEWEB)

    Spaulding, B.C.; Gavalya, R.A.; Dahlmeir, M.M. [and others


    The disposition of INEEL radioactive wastes is now under a Settlement Agreement between the DOE and the State of Idaho. The Settlement Agreement requires that existing liquid sodium bearing waste (SBW), and other liquid waste inventories be treated by December 31, 2012. This agreement also requires that all HLW, including calcined waste, be disposed or made road ready to ship from the INEEL by 2035. Sodium bearing waste (SBW) is produced from decontamination operations and HLW from reprocessing of SNF. SBW and HLW are radioactive and hazardous mixed waste; the radioactive constituents are regulated by DOE and the hazardous constituents are regulated by the Resource Conservation and Recovery Act (RCRA). Calcined waste, a dry granular material, is produced in the New Waste Calcining Facility (NWCF). Two primary waste tank storage locations exist at the ICPP: Tank Farm Facility (TFF) and the Calcined Solids Storage Facility (CSSF). The TFF has the following underground storage tanks: four 18,400-gallon tanks (WM 100-102, WL 101); four 30,000-gallon tanks (WM 103-106); and eleven 300,000+ gallon tanks. This includes nine 300,000-gallon tanks (WM 182-190) and two 318,000 gallon tanks (WM 180-181). This study analyzes the closure and subsequent use of the eleven 300,000+ gallon tanks. The 18,400 and 30,000-gallon tanks were not included in the work scope and will be closed as a separate activity. This study was conducted to support the HLW Environmental Impact Statement (EIS) waste separations options and addresses closure of the 300,000-gallon liquid waste storage tanks and subsequent tank void uses. A figure provides a diagram estimating how the TFF could be used as part of the separations options. Other possible TFF uses are also discussed in this study.

  10. Department of the Navy, FY 1999 Amended Budget Estimates (BRAC 93). Base Closure and Realignment, III

    National Research Council Canada - National Science Library


    .... The Navy budget to implement the closures and realignments resulting from these decisions was formulated based on experience gained from closures and realignments achieved thus far and comprehensive...

  11. Preclinical study evaluating a novel trocar site closure system

    Directory of Open Access Journals (Sweden)

    Walker PA


    Full Text Available Peter A Walker,1 Shinil K Shah,1,2 Erik B Wilson11Department of Surgery, University of Texas Medical School at Houston, Houston, TX, USA; 2Michael E DeBakey Institute for Comparative Cardiovascular Science and Biomedical Devices, Texas A&M University, College Station, TX, USAIntroduction: Novel trocar closure devices using subperitoneal anchor placement avoid the need for a closed loop suture, and could allow faster trocar site closure with less risk derived from less instrument penetration into the abdominal cavity while decreasing fascial ischemia and tension. We completed a series of animal experiments to compare the Carter-Thomason® suture closure device and neoClose® AnchorGuide device in order to evaluate device safety, efficacy, and ease of utilization.Methods: A porcine model was utilized where 12 mm port sites were closed with either the Carter-Thomason® device or neoClose® AnchorGuide device. Animals were sacrificed at 14 and 56 days after trocar site closure followed by macroscopic and microscopic wound examination. A second group of animals underwent video analysis to evaluate the time required for fascial closure as well as depth of needle passage into the abdomen.Results: All animals survived to the endpoints (14 and 56 days without mortality or trocar site hernia. A trend towards decreased closure times was identified when using the neoClose® device (t=18.5±2.3 seconds compared to closure with the Carter-Thomason® device (t=32.0±8.9 seconds (P=0.153. A significant decrease in the depth of needle penetration was seen with the neoClose® device (t=31.22±1.45 mm compared to closure with the Carter-Thomason device (t=51.0±3.1 mm (P<0.001. Microscopic analysis showed subperitoneal anchor location at 56 days with minimal fibrosis (neoClose® device compared to nearly complete suture degradation with deep intramuscular location (Carter-Thomason device.Conclusion: Novel trocar closure devices could offer decreased deployment

  12. Soil-Air Mercury Flux near a Large Industrial Emission Source before and after Closure (Flin Flon, Manitoba, Canada). (United States)

    Eckley, Chris S; Blanchard, Pierrette; McLennan, Daniel; Mintz, Rachel; Sekela, Mark


    Prior to its closure, the base-metal smelter in Flin Flon, Manitoba, Canada was one of the North America's largest mercury (Hg) emission sources. Our project objective was to understand the exchange of Hg between the soil and the air before and after the smelter closure. Field and laboratory Hg flux measurements were conducted to identify the controlling variables and used for spatial and temporal scaling. Study results showed that deposition from the smelter resulted in the surrounding soil being enriched in Hg (up to 99 μg g(-1)) as well as other metals. During the period of smelter operation, air concentrations were elevated (30 ± 19 ng m(-3)), and the soil was a net Hg sink (daily flux: -3.8 ng m(-2) h(-1)). Following the smelter closure, air Hg(0) concentrations were reduced, and the soils had large emissions (daily flux: 108 ng m(-2) h(-1)). The annual scaling of soil Hg emissions following the smelter closure indicated that the landscape impacted by smelter deposition emitted or re-emitted almost 100 kg per year. Elevated soil Hg concentrations and emissions are predicted to continue for hundreds of years before background concentrations are re-established. Overall, the results indicate that legacy Hg deposition will continue to cycle in the environment long after point-source reductions.

  13. Does staged closure have a worse prognosis in gastroschisis?

    Directory of Open Access Journals (Sweden)

    Augusto Frederico Schmidt


    Full Text Available INTRODUCTION: Correction of gastroschisis can be accomplished by primary or staged closure. There is, however, no consensus regarding the best approach or criteria to favor one method over the other has been established. OBJECTIVE: To compare the outcome of primary and staged closure in newborns with gastroschisis using intravesical pressure (IVP as the decision criterion. PATIENTS & METHODS: We prospectively analyzed 45 newborns with gastroschisis. An IVP with a threshold of 20 cm H2O was used to indicate primary or staged closure, and the outcomes between the two methods were compared. RESULTS AND DISCUSSION: Newborns in whom primary closure was feasible were born at a lower gestational age. There was no significant difference in the frequency of complications, time to begin oral feeding, length of parenteral nutrition or length of hospital stay. Compared with previous reports, our data showed higher rates of prenatal diagnosis and cesarean delivery, a lower average birth weight, a higher rate of small gestational age babies and a more frequent association with intestinal atresia. Conversely, our data showed a lower rate of postoperative necrotizing enterocolitis and a lower average length of hospital stay. CONCLUSION: No significant difference was observed in the outcome of newborns who underwent primary closure or staged closure of gastroschisis when using an IVP below 20 cm H2O as the criterion for primary closure.

  14. A closure relation to molecular theory of solvation for macromolecules (United States)

    Kobryn, Alexander E.

    We propose a closure to the integral equations of molecular theory of solvation, particularly suitable for polar and charged macromolecules in electrolyte solution. This includes such systems as oligomeric polyelectrolytes at a finite concentration in aqueous and various non-aqueous solutions, as well as drug-like compounds in solution. The new closure (KGK closure) imposes the mean spherical approximation (MSA) almost everywhere in the solvation shell but levels out the density distribution function to zero inside the repulsive core and in the spatial regions of strong density depletion emerging due to molecular associative interactions. We test the performance of the KGK closure coupled to the reference interaction site model (RISM) on the examples of LJ liquids, polar and nonpolar molecular solvents, including water, and aqueous solutions of simple ions, and use the KGK closure to obtain the solvation structure and thermodynamics of oligomeric polyelectrolytes and drug-like compounds at a finite concentration in electrolyte solution, for which no convergence is obtained with other closures. We further test the 3D-version of the KGK closure with 3D-RISM for molecular mixtures as well as oligomeric polyelectrolytes and drug-like molecules in electrolyte solutions. 11421 Saskatchewan Drive, Edmonton, Alberta, T6G 2M9, Canada.

  15. Endo-vacuum assisted closure treatment for rectal anastomotic insufficiency. (United States)

    Mees, Soeren Torge; Palmes, Daniel; Mennigen, Rudolf; Senninger, Norbert; Haier, Joerg; Bruewer, Matthias


    Anastomotic insufficiency in patients with colorectal anastomosis is a major complication with high morbidity and mortality. Local treatment with transrectal lavage and drainage can be considered in patient without peritonitis. In order to prevent prolonged wound closure and secondary complications during conservative treatment we investigated the vacuum assisted closure (VAC) in this setting. Ten patients with anastomotic insufficiency after colorectal resections, who did not require transabdominal interventions, were treated with an Endo-vacuum assisted closure dressing (Group A; n = 5) or by transrectal lavage (Group B; n = 5). Time for wound healing, duration of hospitalization and pain assessment were compared in both groups. The Endo-vacuum assisted closure treatment was performed for a median time of 27 days without any vacuum assisted closure associated complications. Wound healing was significantly accelerated in Group A compared to Group B. Time in hospital was slightly shortened in patients with Endo-vacuum assisted closure. Pain assessment in both groups did not show any significant differences. Endo-vacuum assisted closure therapy is a novel approach that can be considered in diverted patients with failed colorectal anastomoses. Larger randomized trials that include complete cost-benefit analyses are needed to establish its role in this setting.

  16. Electrocortical indices of attention correlate with the need for closure. (United States)

    Kossowska, Malgorzata; Czarnek, Gabriela; Wyczesany, Miroslaw; Wronka, Eligiusz; Szwed, Paulina; Bukowski, Marcin


    Need for closure (NFC), defined as a desire for a quick and unambiguous answer to a question and an aversion to uncertainty, usually leads to a more structured, persistent, and rigid cognitive style. We suggested that this cognitive characteristic could be related to differences in a simple sensory gating control mechanism as reflected in event-related potentials (N1 component). We expected that the higher an individual's NFC, the more attention he/she would allocate to the selected stimuli or the feature of the stimuli, which is manifested in an increased N1 component. We tested this assumption in two experiments where NFC was measured by a scale and event-related potentials were recorded during the Stroop task and the Visual Distractor task. In line with the hypotheses, we found that NFC was associated with amplified processing of stimuli at an early sensory stage, which was evidenced in an increased N1 component. We suggested that this early sensory gating mechanism protects high NFC individuals against anxiety-producing uncertainty. Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved.


    Directory of Open Access Journals (Sweden)

    Nishat Sultana Khayoom


    Full Text Available BACKGROUND Anterior chamber depth and lens thickness have been considered as important biometric determinants in primary angle-closure glaucoma. Patients with primary narrow angle may be classified as a primary angle closure suspect (PACS, or as having primary angle closure (PAC or primary angle closure glaucoma (PACG. 23.9% of patients with primary angle closure disease are in India, which highlights the importance of understanding the disease, its natural history, and its underlying pathophysiology, so that we may try to establish effective methods of treatment and preventative measures to delay, or even arrest, disease progression, thereby reducing visual morbidity. AIM To determine the lens thickness using A-scan biometry and its significance in various stages of angle closure disease. MATERIALS AND METHODS Patients attending outpatient department at Minto Ophthalmic Hospital between October 2013 to May 2015 were screened for angle closure disease and subsequently evaluated at glaucoma department. In our study, lens thickness showed a direct correlation with shallowing of the anterior chamber by determining the LT/ ACD ratio. A decrease in anterior chamber depth is proportional to the narrowing of the angle which contributes to the progression of the angle closure disease from just apposition to occlusion enhancing the risk for optic nerve damage and visual field loss. Hence, if the lens thickness values are assessed earlier in the disease process, appropriate intervention can be planned. CONCLUSION Determination of lens changes along with anterior chamber depth and axial length morphometrically can aid in early detection of angle closure. The role of lens extraction for PACG is a subject of increased interest. Lens extraction promotes the benefits of anatomical opening of the angle, IOP reduction and improved vision. This potential intervention may be one among the armamentarium of approaches for PACG. Among the current treatment modalities

  18. Evaluation of a new wound closure device for linear surgical incisions: 3M Steri-Strip S Surgical Skin Closure versus subcuticular closure. (United States)

    Kerrigan, Carolyn L; Homa, Karen


    Technological innovations are often adopted before scientific comparison to an accepted standard. The authors' study compared suture with a new coaptive film device, 3M Steri-Strip S Surgical Skin Closure, on linear incisions. Patients undergoing Wise-pattern breast reduction or abdominal procedures had paired incisions randomly assigned to Steri-Strip S or suture closure. Key outcome measures were closure time, patient comfort, and scar quality at 6 months by patients and surgeons using a new scar evaluation tool, visual assessment of linear scars. Statistical differences between the two closure techniques were assessed by Wilcoxon signed rank test. Of 59 patients, eight were excluded from randomization (a surgeon judged Steri-Strip S to be a nonviable closure technique for mismatched wound edges). Fifty-one patients (breast, n = 24; abdomen, n = 27) were randomized. Operative time with Steri-Strip S for breast was 2.0 minutes (SD = 1.1) versus suture closure at 4.6 minutes (SD = 1.5; p Strip S versus suture for the abdomen was faster (p Strip S and better at 2.6 (SD = 2.9) for suture (p = 0.008). One surgeon rated breast Steri-Strip S scars worse than suture scars (4.3 versus 3.7; p = 0.014). For abdominal scars, there was no difference in the patient or surgeon ratings. Steri-Strip S permits faster wound closure than suture. On the basis of patient reports of comfort and scar quality, surgeons increase efficiency and maintain quality with the use of Steri-Strip S on abdominal wounds but not on breast wounds.

  19. Claudins are essential for cell shape changes and convergent extension movements during neural tube closure. (United States)

    Baumholtz, Amanda I; Simard, Annie; Nikolopoulou, Evanthia; Oosenbrug, Marcus; Collins, Michelle M; Piontek, Anna; Krause, Gerd; Piontek, Jörg; Greene, Nicholas D E; Ryan, Aimee K


    During neural tube closure, regulated changes at the level of individual cells are translated into large-scale morphogenetic movements to facilitate conversion of the flat neural plate into a closed tube. Throughout this process, the integrity of the neural epithelium is maintained via cell interactions through intercellular junctions, including apical tight junctions. Members of the claudin family of tight junction proteins regulate paracellular permeability, apical-basal cell polarity and link the tight junction to the actin cytoskeleton. Here, we show that claudins are essential for neural tube closure: the simultaneous removal of Cldn3, -4 and -8 from tight junctions caused folate-resistant open neural tube defects. Their removal did not affect cell type differentiation, neural ectoderm patterning nor overall apical-basal polarity. However, apical accumulation of Vangl2, RhoA, and pMLC were reduced, and Par3 and Cdc42 were mislocalized at the apical cell surface. Our data showed that claudins act upstream of planar cell polarity and RhoA/ROCK signaling to regulate cell intercalation and actin-myosin contraction, which are required for convergent extension and apical constriction during neural tube closure, respectively. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.


    Pak, Kang Yeun; Park, Keun Heung; Kim, Kyong Ho; Park, Sung Who; Byon, Ik Soo; Kim, Hyun Woong; Chung, In Young; Lee, Joo Eun; Lee, Sang Joon; Lee, Ji Eun


    To investigate retinal displacement in the macula after surgical closure of idiopathic macular hole and to identify factors correlated with displacement. This retrospective multicenter study included 73 eyes of 73 patients having idiopathic macular hole. A custom program was developed to compare the position of the retinal vessels in the macula between preoperative and postoperative photographs. En face images of a 6 mm × 6 mm optical coherence tomography volume scans were registered to calculate the scale. A grid comprising 16 sectors in 2 rings (inner; 2-4 mm and outer; 4-6 mm) was superimposed. The displacement of the retinal vessels was measured as a vector value by comparing the location of the retinal vessels in each sector. The correlation between displacement and various clinical parameters was analyzed. The average displacement was 57.2 μm at an angle of -3.3° (nasal and slightly inferior). Displacement was larger in the inner ring (79.2 μm) than in the outer ring (35.3 μm, P macula was displaced centripetally, nasally, and slightly inferiorly after surgical closure of idiopathic macular hole. Hole closure, contraction of the nerve fiber layer, and gravity are the suggested mechanisms of macular displacement caused by internal limiting membrane peeling.

  1. Surgical staples compared with subcuticular suture for skin closure after cesarean delivery: a randomized controlled trial. (United States)

    Figueroa, Dana; Jauk, Victoria Chapman; Szychowski, Jeff M; Garner, Rachel; Biggio, Joseph R; Andrews, William W; Hauth, John; Tita, Alan T N


    To compare the risk of cesarean wound disruption or infection after closure with surgical staples compared with subcuticular suture. Women with viable pregnancies at 24 weeks of gestation or greater undergoing scheduled or unscheduled cesarean delivery were randomized to wound closure with surgical staples or absorbable suture. Staples were removed at postoperative days 3-4 for low transverse incisions and days 7-10 for vertical incisions. Standardized wound evaluations were performed at discharge (days 3-4) and 4-6 weeks postoperatively. The primary outcome was a composite of wound disruption or infection within 4-6 weeks. Secondary outcomes included operative time, highest pain score on analog scale, cosmesis score, and patient scar satisfaction score. Analyses were by intent to treat. Of 398 patients, 198 were randomized to staples and 200 to suture (but four received staples). Baseline characteristics including body mass index, prior cesarean delivery, labor, and type of skin incision were similar by group. The primary outcome incidence at hospital discharge was 7.1% for staples and 0.5% for suture (Psuture (P=.008, relative risk 2.5, 95% CI 1.2-5.0). Operative time was longer with suture closure (median time of 58 versus 48 minutes; Psuture is associated with significantly increased composite wound morbidity after cesarean delivery. :,, NCT01008449. : I.

  2. Transportable Vitrification System RCRA Closure Practical Waste Disposition Saves Time And Money

    Energy Technology Data Exchange (ETDEWEB)

    Brill, Angie; Boles, Roger; Byars, Woody


    The Transportable Vitrification System (TVS) was a large-scale vitrification system for the treatment of mixed wastes. The wastes contained both hazardous and radioactive materials in the form of sludge, soil, and ash. The TVS was developed to be moved to various United States Department of Energy (DOE) facilities to vitrify mixed waste as needed. The TVS consists of four primary modules: (1) Waste and Additive Materials Processing Module; (2) Melter Module; (3) Emissions Control Module; and (4) Control and Services Module. The TVS was demonstrated at the East Tennessee Technology Park (ETTP) during September and October of 1997. During this period, approximately 16,000 pounds of actual mixed waste was processed, producing over 17,000 pounds of glass. After the demonstration was complete it was determined that it was more expensive to use the TVS unit to treat and dispose of mixed waste than to direct bury this waste in Utah permitted facility. Thus, DOE had to perform a Resource Conservation and Recovery Act (RCRA) closure of the facility and find a reuse for as much of the equipment as possible. This paper will focus on the following items associated with this successful RCRA closure project: TVS site closure design and implementation; characterization activities focused on waste disposition; pollution prevention through reuse; waste minimization efforts to reduce mixed waste to be disposed; and lessons learned that would be integrated in future projects of this magnitude.

  3. A new bipolar feedback-controlled sealing system for closure of the cystic duct and artery. (United States)

    Shamiyeh, A; Schrenk, P; Tulipan, L; Vattay, P; Bogner, S; Wayand, W


    Bile leaks are serious complications after laparoscopic cholecystectomy. The aim of this study was to evaluate the feasibility of closure of the cystic duct with a new feedback-controlled bipolar sealing system (LigaSure). Ten domestic pigs underwent open cholecystectomy with the cystic duct and artery dissected and sealed with the new bipolar sealing system (LigaSure). Four and 8 days postoperatively, 5 pigs each were sacrificed and the closure of the cystic duct was evaluated. The cystic stump and the common bile duct were excised for histological examination. None of the pigs had a bile leak or a biliary peritonitis. There were no signs of postoperative bleeding or inflammation in Calot's triangle. Histology showed total necrosis of the cystic duct in the first two pigs due to too much energy used. The remaining specimens showed a regularly scaling zone without necrosis in 7 cases, and in one case a partial necrosis in the mucosa only was found. Cystic artery and cystic duct closure with the new device may be an alternative to the clip. Further trials should evaluate the feasibility and safety of the new device in the clinical setting.

  4. Comparison of Outcomes between Early Fascial Closure and Delayed Abdominal Closure in Patients with Open Abdomen: A Systematic Review and Meta-Analysis (United States)

    Chen, Yu; Ye, Jinning; Song, Wu; Chen, Jianhui; Yuan, Yujie; Ren, Jianan


    Up to the present, the optimal time to close an open abdomen remains controversial. This study was designed to evaluate whether early fascial abdominal closure had advantages over delayed approach for open abdomen populations. Medline, Embase, and Cochrane Library were searched until April 2013. Search terms included “open abdomen,” “abdominal compartment syndrome,” “laparostomy,” “celiotomy,” “abdominal closure,” “primary,” “delayed,” “permanent,” “fascial closure,” and “definitive closure.” Open abdomen was defined as “fail to close abdominal fascia after a laparotomy.” Mortality, complications, and length of stay were compared between early and delayed fascial closure. In total, 3125 patients were included for final analysis, and 1942 (62%) patients successfully achieved early fascial closure. Vacuum assisted fascial closure had no impact on pooled fascial closure rate. Compared with delayed abdominal closure, early fascial closure significantly reduced mortality (12.3% versus 24.8%, RR, 0.53, P closure ranged from 2.2 to 14.6 days in early fascial closure groups, but from 32.5 to 300 days in delayed closure groups. This study confirmed clinical advantages of early fascial closure over delayed approach in treatment of patients with open abdomen. PMID:24987411

  5. Comparison of Outcomes between Early Fascial Closure and Delayed Abdominal Closure in Patients with Open Abdomen: A Systematic Review and Meta-Analysis

    Directory of Open Access Journals (Sweden)

    Yu Chen


    Full Text Available Up to the present, the optimal time to close an open abdomen remains controversial. This study was designed to evaluate whether early fascial abdominal closure had advantages over delayed approach for open abdomen populations. Medline, Embase, and Cochrane Library were searched until April 2013. Search terms included “open abdomen,” “abdominal compartment syndrome,” “laparostomy,” “celiotomy,” “abdominal closure,” “primary,” “delayed,” “permanent,” “fascial closure,” and “definitive closure.” Open abdomen was defined as “fail to close abdominal fascia after a laparotomy.” Mortality, complications, and length of stay were compared between early and delayed fascial closure. In total, 3125 patients were included for final analysis, and 1942 (62% patients successfully achieved early fascial closure. Vacuum assisted fascial closure had no impact on pooled fascial closure rate. Compared with delayed abdominal closure, early fascial closure significantly reduced mortality (12.3% versus 24.8%, RR, 0.53, P<0.0001 and complication incidence (RR, 0.68, P<0.0001. The mean interval from open abdomen to definitive closure ranged from 2.2 to 14.6 days in early fascial closure groups, but from 32.5 to 300 days in delayed closure groups. This study confirmed clinical advantages of early fascial closure over delayed approach in treatment of patients with open abdomen.

  6. Isotretinoin-induced Angle Closure and Myopic Shift. (United States)

    Park, Young-Myoung; Lee, Tae-Eun


    To report and describe the management a rare case of transient bilateral angle closure with increased intraocular pressure (IOP) and myopic shift while on isotretinoin therapy for acne. A 28-year-old woman presented with bilateral myopic shift, angle closure with IOP increase, and supraciliary effusion 1 week after acne therapy with isotretinoin. Two weeks after stopping isotretinoin, and treatment with topical prednisolone acetate, atropine, and fixed combination of timolol and dorzolamide, refraction, IOP returned to normal and supraciliary effusions was decreased on ultrasound biomicroscopy. Oral isotretinoin for acne treatment may be associated with an adverse reaction, resulting in bilateral transient myopia and angle closure with IOP elevation.

  7. Use of bipedicular advancement flaps for intrauterine closure of myeloschisis. (United States)

    Mangels, K J; Tulipan, N; Bruner, J P; Nickolaus, D


    Several groups have begun to explore the feasibility and utility of intrauterine closure of myelomeningocele. A subset of these fetuses have defects which fall into the category of myeloschisis, and therefore have inadequate skin to enable primary closure. After considerable discussion, it was decided to utilize bipedicular flaps to close these lesions. The procedure is described, and representative examples are shown. To date, 13 of 56 fetuses have required this approach for closure in utero. While this technique generally provides adequate coverage of the dural sac, the cosmetic results have been less than optimal. Copyright 2000 S. Karger AG, Basel

  8. The use of chicken legs for teaching wound closure skills

    Directory of Open Access Journals (Sweden)

    Khalil PN


    Full Text Available Abstract Objective Training models are required to impart surgical skills, like wound closure techniques, prior to practice in patients. In an ideal case, the tissue characteristics of the model are close to those of humans, easy to create and of low cost. Methods Here, we describe a model to train students in wound closure technique using conventional chicken legs obtained from the supermarket. Results The described model has good tissue characteristics, does not require any lavish preparation and is of minimal cost (0.62 Euro or 0.78 USD. Conclusions Chicken legs appear to be an appropriate tool for teaching wound closure techniques.

  9. Predictors of successful closure of patent ductus arteriosus with indomethacin. (United States)

    Ahamed, M F; Verma, P; Lee, S; Vega, M; Wang, D; Kim, M; Fuloria, M


    To determine whether platelet counts can predict the likelihood of successful closure of patent ductus arteriosus (PDA) with indomethacin. This was a retrospective cohort study of infants gender (odds ratio=3.02; 95% confidence interval: 1.08 to 8.49) and higher platelet count (odds ratio=1.5; 95% confidence interval: 1.04 to 2.17) prior to indomethacin treatment were associated with successful ductal closure with indomethacin. Older GA, male gender and higher platelet count at time of treatment of hemodynamically significant PDA are predictors of successful ductal closure with indomethacin.

  10. Assessment of consistent two-equation closure for forest flows

    DEFF Research Database (Denmark)

    Sogachev, Andrey; Cavar, Dalibor; Bechmann, Andreas

    of grid turbulence and wall-bounded flow, the closure suggested is also valid for homogeneous shear flows commonly observed inside tall vegetative canopies. The present work assess the plant drag closure by comparing results of two different CFD models against observations derived over the forested area...... of Østerild in Denmark. Part of the forest was cut in 2011, and this provided a unique opportunity for testing models allowing two scenarios for land use and corresponding observation datasets (2008 – 2013). The numerical experiments show that the treatment of plant drag in the closure has universality...

  11. Antiplatelet effects of clopidogrel and aspirin after interventional patent foramen ovale/ atrium septum defect closure. (United States)

    Polzin, Amin; Dannenberg, Lisa; Sophia Popp, Valérie-; Kelm, Malte; Zeus, Tobias


    The optimal antiplatelet therapy after patent foramen ovale (PFO)/ atrium septum defect (ASD) closure is a matter of discussion. It is challenging as inter-individual responses to antiplatelet medication vary significantly and common complications are bleeding and ischemic events. In this study, we aimed to analyze the incidence of high on-treatment platelet reactivity (HTPR) to antiplatelet medication in patients undergoing PFO/ASD closure as well as clinical complications and thrombus formation on the occluder during six-month follow-up. This hypothesis generating pilot study was observed, which included 140 patients undergoing PFO/ASD closure. The primary endpoint was pharmacodynamic response to antiplatelet medication. A composite of death, myocardial infarction, bleeding, stroke and thrombus formation on the occluder during six-month follow-up was the secondary endpoint. HTPR to clopidogrel was analyzed using the vasodilator-stimulated protein phosphorylation (VASP), HTPR to aspirin by light-transmission aggregometry (LTA). In 71% of patients HTPR to clopidogrel was detected, HTPR to aspirin in only 4%. We observed 12 complications, 9 bleeding events (including 3 major bleeding events) and 3 transient ischemic attacks. No stroke and no thrombus formation on the occluder occurred. The primary endpoint was not associated with the secondary endpoint. The incidence of HTPR to clopidogrel in PFO/ASD closure patients is very high. Despite this high incidence, no stroke or thrombus formation on the occluder occurred at all. This leads to the hypothesis, that the benefit of additional clopidogrel medication is questionable and has to be investigated in large-scale clinical trials.

  12. The impact of topical lidocaine on pain level assessment during and after vacuum-assisted closure dressing changes: a double-blind, prospective, randomized study. (United States)

    Franczyk, Mieczyslawa; Lohman, Robert F; Agarwal, Jayant P; Rupani, Gita; Drum, Melinda; Gottlieb, Lawrence J


    Vacuum-assisted closure dressing changes are frequently painful. The authors hypothesized that administering topical lidocaine into the vacuum-assisted closure sponge would decrease pain during dressing changes. A double-blind, randomized, prospective study was performed on patients (n = 70) undergoing vacuum-assisted closure dressing changes at a single institution between October of 2003 and June of 2005. Patients were randomized to receive either 0.2% lidocaine or 0.9% saline administered through the vacuum-assisted closure tubing into the foam dressing 30 minutes before changing the dressing. All patients received morphine sulfate ad libitum. Pain scores were assessed according to a 0 to 10 numeric pain scale. Wound characteristics and patient demographics were similar for both groups. Patients receiving lidocaine reported less pain than control patients during the dressing change (4.3 versus 6.3; p = 0.005) and immediately after (2.4 versus 4.7; p 3 mg morphine equivalent) than in the control group. During the initial vacuum-assisted closure dressing change, 0.2% lidocaine administered through the suction tubing led to a reduction in pain reported by the patients in the authors' study. The duration of lidocaine administered in this fashion may be fairly short, because more patients in this group began to request small doses of opiates 30 minutes after the dressing change. Thus, lidocaine may improve patient comfort during vacuum-assisted closure therapy.

  13. Case Report: Rapid staged abdominal closure using Gore-Tex® mesh as a bridge to primary omphalocele sac closure

    Directory of Open Access Journals (Sweden)

    William C. Kethman


    Full Text Available Omphaloceles present an ongoing challenge due to significant variations in presentation and associated co-morbidities. Diverse management strategies have been described to tackle many of the fundamental challenges of closure and reconstruction of the abdominal wall – this fact demonstrates a need for increasingly individualized management options for this complex disease. We describe a novel method of rapid staged abdominal wall closure using Gore-Tex® mesh as a bridge to primary omphalocele closure in an infant with partial Pentalogy of Cantrell and giant ruptured omphalocele. This strategy can be used in management of some of the most complex abdominal wall defects.

  14. Don’t call it a closure!

    CERN Multimedia

    Rosaria Marraffino


    During the Laboratory’s annual closure, some members of the personnel joined their families, others seized the chance to travel the world. The Restaurants were closed, the corridors were dark and the heating was turned off in most of the buildings. However, a lot of people spent the Christmas break working on site and the Bulletin would like to dedicate this first article of the new year to them all!   In the CERN Control Centre (CCC), each shift had two people in position to guarantee regular 24/7 service and to intervene in case of need. Gildas Langlois and Rodolphe Maillet, CCC operators from the Beams Department, spent Christmas Eve there and celebrated it with a cake. “I volunteered to work during the holidays in order to allow colleagues to stay with their families,” says Maillet. On New Year’s Eve, it was Julien Pache and Jean-Michel Nonglaton’s turn to spend the night at work. They had a nice dinner with a CCC-made fondue and some desse...

  15. IT Services availability during CERN annual closure

    CERN Multimedia


    Mail, Cern Windows (NICE ),  Web services,  LXPLUS, LXBATCH, Automated tape devices, Castor, Backups, software license servers, Sundev, CVS and Print Servers, CDS and Agenda-Maker, EDMS (in collaboration with EST Division), CMS disc servers, Campus Network,  Remedy, Security and VPN services will be available during the CERN annual closure. The physics database cluster, replication location service as well as accdb, cerndb and admsdb are the only databases available, CCDB will be closed for public access. Problems developing on scheduled services should be addressed within about half a day except around  Christmas Eve and Christmas Day ( 24 and 25th December ) and New Year's Eve and New Years Day (31st December and 1st Janauary. All other services will be left running mostly unattended. No interruptions are scheduled but restoration of the service in case of failure cannot be guaranteed. Please note that the Helpdesk will be closed, that no file restores from backups will be possible and damaged tapes wi...

  16. Angle Closure Scoring System (ACSS-A Scoring System for Stratification of Angle Closure Disease.

    Directory of Open Access Journals (Sweden)

    Aparna Rao

    Full Text Available To evaluate the angle closure scoring system (ACSS for stratifying primary angle course disease.This observational cross sectional institutional study included patients with primary open angle glaucoma suspects (n = 21 and primary angle closure disease (primary angle closure, PAC, n = 63 and primary angle course glaucoma, PACG, n = 58 (defined by International society of Geographical and Epidemiological Ophthalmology, ISGEO. Two independent examiners blinded to clinical details, graded good quality pre-laser goniophotographs of the patients incorporating quadrants of peripheral anterior synechieae (PAS, non-visibility of posterior trabecular meshwork (PTM and blotchy pigments (ranging from 1-4 quadrants, iris configuration, angle recess (sum of above depicting ACSSg and lens thickness/axial length ratio (LT/AL, cup disc ratio and baseline intraocular pressure (IOP to give total score (ACSSt.There were significant differences in ACSSg scores within the same ISGEO stage of PAC and PACG between eyes that required nil or >1medicines after laser iridotomy, p1 medicines in both PAC and PACG eyes, p12 and 14 in PAC (odds ratio = 2.7(95% CI-1.7-5.9 and PACG (Odds ratio = 1.6(95%CI-1.19-2.2 predicted need for single medicines while ACSSg scores >14 and 19 predicted need for ≥2 medicines in PAC and PACG eyes, respectively. The LT/Al ratio, IOP score or cup disc score did not influence the need for medical treatment independently.The ACSS can be a useful clinical adjunct to the ISGEO system to predict need for medicines and prognosticate each stage more accurately.

  17. Angle Closure Scoring System (ACSS)-A Scoring System for Stratification of Angle Closure Disease (United States)

    Rao, Aparna; Padhy, Debananda; Sarangi, Sarada; Das, Gopinath


    Purpose To evaluate the angle closure scoring system (ACSS) for stratifying primary angle course disease. Methods This observational cross sectional institutional study included patients with primary open angle glaucoma suspects (n = 21) and primary angle closure disease (primary angle closure, PAC, n = 63 and primary angle course glaucoma, PACG, n = 58 (defined by International society of Geographical and Epidemiological Ophthalmology, ISGEO). Two independent examiners blinded to clinical details, graded good quality pre-laser goniophotographs of the patients incorporating quadrants of peripheral anterior synechieae (PAS), non-visibility of posterior trabecular meshwork (PTM) and blotchy pigments (ranging from 1–4 quadrants), iris configuration, angle recess (sum of above depicting ACSSg) and lens thickness/axial length ratio (LT/AL), cup disc ratio and baseline intraocular pressure (IOP) to give total score (ACSSt). Result There were significant differences in ACSSg scores within the same ISGEO stage of PAC and PACG between eyes that required nil or >1medicines after laser iridotomy, p1 medicines in both PAC and PACG eyes, p12 and 14 in PAC (odds ratio = 2.7(95% CI-1.7–5.9) and PACG (Odds ratio = 1.6(95%CI-1.19–2.2) predicted need for single medicines while ACSSg scores >14 and 19 predicted need for ≥2 medicines in PAC and PACG eyes, respectively. The LT/Al ratio, IOP score or cup disc score did not influence the need for medical treatment independently. Conclusion The ACSS can be a useful clinical adjunct to the ISGEO system to predict need for medicines and prognosticate each stage more accurately. PMID:27788183

  18. Implementing the Western Gulf of Maine Area Closure: The Role and Perception of Fishers' Ecological Knowledge

    Directory of Open Access Journals (Sweden)

    Mateja Nenadovic


    Full Text Available The debate about the quality of fishers' ecological knowledge (FEK and its value to fisheries management has long been present in the literature. This study sought to understand the role of FEK in a particular fisheries management decision in the U.S. and to evaluate the extent that different stakeholder groups recognized and used FEK in fisheries policy creation. The 1998 implementation of the Western Gulf of Maine Area Closure (WGoMAC was a management response to the rapid decline in the Gulf of Maine cod (Gadus morhua stock. Using structured surveys and semistructured interviews, we collected information from major stakeholder groups that were active during the creation of the area closure: New England Fishery Management Council (NEFMC members, Groundfish Advisory Panel members, Groundfish Plan Development Team members, and Maine groundfishers. Results indicated that 95% of respondents believed that fishers possess ecological knowledge that could be useful in the fishery management process. In the case of the WGoMAC creation, 62% of respondents indicated that FEK played a role in the decision, even though 85% recognized obstacles to the use of FEK in the management process. Interviews demonstrated that FEK was able to improve upon the spatial resolution of scientific data by identifying seasonal migration patterns of prespawning cod and behavioral differences between juvenile and adult cod. This information was a product of a peer-reviewed process among groundfishers and it was used to fine-tune the exact location of the closure. These findings suggest that there are ways to incorporate FEK into fishery management for the purposes of stock and habitat conservation. Additionally, the benefit of having ecological information that spans different spatial scales for fishery management was observed in this study. By combining the knowledge systems of fishers and fisheries scientists, managers were able to capture ecological information at a finer

  19. Neural tube closure: cellular, molecular and biomechanical mechanisms. (United States)

    Nikolopoulou, Evanthia; Galea, Gabriel L; Rolo, Ana; Greene, Nicholas D E; Copp, Andrew J


    Neural tube closure has been studied for many decades, across a range of vertebrates, as a paradigm of embryonic morphogenesis. Neurulation is of particular interest in view of the severe congenital malformations - 'neural tube defects' - that result when closure fails. The process of neural tube closure is complex and involves cellular events such as convergent extension, apical constriction and interkinetic nuclear migration, as well as precise molecular control via the non-canonical Wnt/planar cell polarity pathway, Shh/BMP signalling, and the transcription factors Grhl2/3, Pax3, Cdx2 and Zic2. More recently, biomechanical inputs into neural tube morphogenesis have also been identified. Here, we review these cellular, molecular and biomechanical mechanisms involved in neural tube closure, based on studies of various vertebrate species, focusing on the most recent advances in the field. © 2017. Published by The Company of Biologists Ltd.

  20. Estimation of crown closure from AVIRIS data using regression analysis (United States)

    Staenz, K.; Williams, D. J.; Truchon, M.; Fritz, R.


    Crown closure is one of the input parameters used for forest growth and yield modelling. Preliminary work by Staenz et al. indicates that imaging spectrometer data acquired with sensors such as the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) have some potential for estimating crown closure on a stand level. The objectives of this paper are: (1) to establish a relationship between AVIRIS data and the crown closure derived from aerial photography of a forested test site within the Interior Douglas Fir biogeoclimatic zone in British Columbia, Canada; (2) to investigate the impact of atmospheric effects and the forest background on the correlation between AVIRIS data and crown closure estimates; and (3) to improve this relationship using multiple regression analysis.

  1. IDP camp closure and gender inequality in Timor-Leste

    Directory of Open Access Journals (Sweden)

    Phyllis Ferguson


    Full Text Available The goal of humanitarian assistance in Timor-Leste during a seriesof crises from 2006 to 2008 became increasingly focused on IDPcamp closure, with the assisted return of IDPs to their communitiesor to alternative living situations.

  2. Underground storage tank 253-D1U1 Closure Plan

    Energy Technology Data Exchange (ETDEWEB)

    Mancieri, S.; Giuntoli, N.


    This report is a closure plan for a diesel fuel tank at the Lawrence Livermore National Laboratory. Included are maps of the site, work plans, and personnel information regarding training and qualification.

  3. 300 Area waste acid treatment system closure plan. Revision 1

    Energy Technology Data Exchange (ETDEWEB)



    This section provides a description of the Hanford Site, identifies the proposed method of 300 Area Waste Acid Treatment System (WATS) closure, and briefly summarizes the contents of each chapter of this plan.

  4. Procedures adopted by orthodontists for space closure and anchorage control

    Directory of Open Access Journals (Sweden)

    André da Costa Monini


    Full Text Available OBJECTIVE: The aim of this study was to identify the procedures adopted by Brazilian orthodontists in the following situations: extraction space closure, anchorage control in case of necessary anchorage for group A and frequency of skeletal anchorage use, especially in the upper jaw. METHOD: A questionnaire was sent to the e-mail address of all dentists registered in the Brazilian Federal Council of Dentistry. RESULTS: The results showed that most Brazilian orthodontists usually perform extraction space closure by means of sliding mechanics. The use of palatal bar, inclusion of second molars in the archwire and space closure performed in two phases are the most used techniques for anchorage control in the upper jaw. The skeletal anchorage is referenced by 36.5% of specialists as a routine practice for the upper jaw anchorage. CONCLUSIONS: There is a wide variety of procedures adopted by Brazilian orthodontists for orthodontic space closure and anchorage control.

  5. 300 Area waste acid treatment system closure plan

    Energy Technology Data Exchange (ETDEWEB)

    LUKE, S.N.


    The Hanford Facility Dangerous Waste Permit Application is considered to be a single application organized into a General Information Portion (document number DOERL-91-28) and a Unit-Specific Portion. The scope of the Unit-Specific Portion includes closure plan documentation submitted for individual, treatment, storage, and/or disposal units undergoing closure, such as the 300 Area Waste Acid Treatment System. Documentation contained in the General Information Portion is broader in nature and could be used by multiple treatment, storage, and/or disposal units (e.g., the glossary provided in the General Information Portion). Whenever appropriate, 300 Area Waste Acid Treatment System documentation makes cross-reference to the General Information Portion, rather than duplicating text. This 300 Area Waste Acid Treatment System Closure Plan (Revision 2) includes a Hanford Facility Dangerous Waste Permit Application, Part A, Form 3. Information provided in this closure plan is current as of April 1999.

  6. Threats and opportunities for post-closure development in dolomitic ...

    African Journals Online (AJOL)

    Threats and opportunities for post-closure development in dolomitic gold mining areas of the West Rand and Far West Rand (South Africa) – a hydraulic view Part 3: Planning and uncertainty – lessons from history.

  7. Acute Angle Closure Secondary to Tubercular Choroidal Granuloma. (United States)

    Kaushik, Sushmita; Singh, Ramandeep; Arora, Atul; Joshi, Gunjan; Sharma, Kusum; Tigari, Basavraj


    Acute angle closure is usually thought to be secondary to pupillary block, which is relieved by laser iridotomy. Anterior rotation of the ciliary body at the scleral spur following development of an inflammatory ciliochoroidal detachment may result in a presentation of acute angle closure. It is imperative to recognize this condition correctly, because the management is with cycloplegics and anti-inflammatory drugs, which is diametrically opposite to the treatment of primary angle closure. More importantly, it has been reported as a consequence of serious systemic disease such as HIV infection and Vogt Koyanagi Harada (VKH) syndrome. We report a patient who presented to the medical emergency with headache and vomiting and was subsequently found to have acute angle closure in 1 eye secondary to a tubercular choroidal granuloma. This presentation of ocular tuberculosis has not been reported previously.

  8. Autocracy bias in informal groups under need for closure. (United States)

    Pierro, Antonio; Mannetti, Lucia; De Grada, Eraldo; Livi, Stefano; Kruglanski, Arie W


    Two experiments investigated the tendency of groups with members under high (vs. low) need for cognitive closure to develop an autocratic leadership structure in which some members dominate the discussion, constitute the "hubs" of communication, and influence the group more than other members. The first experiment found that high (vs. low) need for closure groups, as assessed via dispositional measure of the need for closure, manifested greater asymmetry of conversational floor control, such that members with autocratic interactional style were more conversationally dominant and influential than less autocratic members. The second experiment manipulated the need for closure via time pressure and utilized a social network analysis. Consistent with expectation, groups under time pressure (vs. no pressure) showed a greater asymmetry of participation, of centrality, and of prestige among the group members, such that the more focal members were perceived to exert the greater influence over the groups' decisions.

  9. Economic evaluation of closure cap barrier materials study

    Energy Technology Data Exchange (ETDEWEB)

    Serrato, M.G.; Bhutani, J.S.; Mead, S.M.


    Volume II of the Economic Evaluation of the Closure Cap Barrier Materials, Revision I contains detailed cost estimates for closure cap barrier materials. The cost estimates incorporate the life cycle costs for a generic hazardous waste seepage basin closure cap under the RCRA Post Closure Period of thirty years. The economic evaluation assessed six barrier material categories. Each of these categories consists of several composite cover system configurations, which were used to develop individual cost estimates. The information contained in this report is not intended to be used as a cost estimating manual. This information provides the decision makers with the ability to screen barrier materials, cover system configurations, and identify cost-effective materials for further consideration.


    Energy Technology Data Exchange (ETDEWEB)



    The purpose of this Closure Report is to document that the closure of CAU 214 complied with the Nevada Division of Environmental Protection-approved Corrective Action Plan closure requirements. The closure activities specified in the Corrective Action Plan were based on the approved corrective action alternatives presented in the CAU 214 Corrective Action Decision Document.

  11. Starting at the End When Planning for Base Closure (United States)


    Transfer Property Early An equally critical aspect of base closure that included the direct in- volvement and support of numerous contractors and...operations shaped the tempo of the overall base transfer. By involving engineer assets early , the RSS successfully set the conditions for closure. A...order-style mes- sages with all personnel on the base, including contractors , to ensure that everyone was aware of drawdown requirements and could

  12. An Unusual Mechanism of Closure of Muscular Ventricular Septal Defects

    Directory of Open Access Journals (Sweden)

    Soham Dasgupta


    Full Text Available Ventricular septal defects (VSDs are the most common congenital heart defects. Most of the small or moderate size (<6 mm muscular VSDs close spontaneously within the first two years of life. The usual mechanism of spontaneous closure involves muscular tissue encroachment with superimposed fibrosis or primary fibrous tissue formation around the margins of the defect. We describe an unusual mechanism of spontaneous closure of a muscular VSD.

  13. Diastema Closure in Anterior Teeth Using a Posterior Matrix


    Ayush Goyal; Vineeta Nikhil; Ritu Singh


    Presence of diastema between anterior teeth is often considered an onerous esthetic problem. Various treatment modalities are available for diastema closure. However, not all diastemas can be treated the same in terms of modality or timing. The extent and the etiology of the diastema must be properly evaluated. Proper case selection is of paramount importance for a successful treatment. In this case report, diastema closure was performed with direct composite restorations. One bottle etch-and...

  14. The reading man flap for closure of large meningomyelocele defects. (United States)

    Mutaf, Mehmet; Temel, Metin; Günal, Ertan


    Closure of the skin defect in myelomeningocele repair is an essential step that determines the quality of the surgical result. In large myelomeningoceles, however, adequate skin coverage may not be accomplished by direct closure or skin undermining. In such cases, the skin defect is best repaired using flaps. The aim of this study is to evaluate the reading man procedure for closure of large meningomyelocele defect. In this procedure, after neurosurgical repair and closure of the placode, the defect surgically becomes a circle in shape. Then, the circular defect is closed by transposition of two skin flaps designed in an unequal Z-plasty manner. Over 5 years, the reading man procedure was used for closure of large meningomyelocele defects in seven patients (four females and three males), aged between 1.5 and 6 months. The defect size was 10.5×7.25 cm (8.5×5.3 and 12.6×9.5 cm) on average. The localisation of the lesions was thoracolumbar in two patients and lumbosacral in five patients. In all patients, a successful tension-free one-stage closure was obtained without dog-ear formation. Except for one patient with minimal tip necrosis, healing was uneventful without any complications. There was no patient with late breakdown of the wound during 1.5 years (8 months-4 years) of mean follow-up. The reading man procedure enables the surgeon to achieve a tension-free defect closure of considerably large meningomyeleocele defects. Using two well-vascularised fasciocutaneous flaps, it provides a durable coverage and soft tissue padding over the neural tissues with no suture seam at midline. With these advantages, the Reading Man Procedure seems to be a useful and safe alternative for closure of large meningomyelocele defects. Copyright © 2011 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

  15. Neural tube closure in the chick embryo is multiphasic. (United States)

    Van Straaten, H W; Janssen, H C; Peeters, M C; Copp, A J; Hekking, J W


    Progression of neurulation in the chick embryo has not been well documented. To provide a detailed description, chick embryos were stained in ovo after the least manipulation possible to avoid distortion of the neural plate and folds. This allowed a morphological and morphometric description of the process of neurulation in relatively undisturbed chick embryos. Neurulation comprises several specific phases with distinct closure patterns and closure rates. The first closure event occurs, de novo, in the future mesencephalon at the 4-6 somite stage (sst 4-6). Soon afterwards, at sst 6-7, de novo closure is seen at the rhombocervical level in the form of multisite contacts of the neural folds. These contacts occur in register with the somites, suggesting that the somites may play a role in forcing elevation and apposition of the neural folds. The mesencephalic] and rhombocervical closure events define an intervening rhombencephalic neuropore, which is present for a brief period before it closes. The remaining pear-shaped posterior neuropore (PNP) narrows and displaces caudally, but its length remains constant in embryos with seven to ten somites, indicating that the caudal extension of the rhombocervical closure point and elongation of the caudal neural plate are keeping pace with each other. From sst 10 onward, the tapered cranial portion of the PNP closes fast in a zipper-like manner, and, subsequently, the wide caudal portion of the PNP closes rapidly as a result of the parallel alignment of its folds, with numerous button-like temporary contact points. A role for convergent extension in this closure event is suggested. The final remnant of the PNP closes at sst 18. Thus, as in mammals, chick neurulation involves multisite closure and probably results form several different development mechanisms at varying levels of the body axis.

  16. Crack closure on rehydration of glass-ionomer materials. (United States)

    Sidhu, Sharanbir K; Pilecki, Peter; Sherriff, Martyn; Watson, Timothy F


    Moisture-sensitivity of immature glass-ionomer cements suggests that hydration-induced volumetric expansion might close and potentially heal established cracks. Crack closure in glass-ionomer cements (GICs) was observed following rehydration. Circular cavities were prepared in 15 teeth: 10 were restored with resin-modified GICs (5 with Fuji II LC and 5 with Photac-Fil) and 5 were restored with a conventional GIC (Fuji IX); all were dehydrated for 1 min with air and imaged immediately by confocal microscopy. Crack formation in each was located, after which water was placed on the surface and observed for 15 min via a CCD camera. Dehydration caused cracks with measurable gaps, while rehydration resulted in varying degrees of closure: closure was limited in the conventional GIC, and complete or near complete along part/s of the crack in the resin-modified GICs. In all, closure movement became imperceptible after the first 10 min. Statistical analysis indicated no significant difference between the closure behavior of all materials. However, the resin-modified GICs appeared to show a greater potential for closure of established cracks than the conventional GIC upon rehydration.

  17. Delayed dynamic abdominal wall closure following multi-visceral transplantation. (United States)

    Iype, Satheesh; Butler, Andrew; Jamieson, Neville; Middleton, Stephen; Jah, Asif


    Primary closure of the abdominal wall following intestinal transplantation or multivisceral transplantation could become a challenging problem in a significant number of patients. A 38-year-old woman with familial adenomatous polyposis (FAP) underwent a multi-visceral transplantation for short gut syndrome. She subsequently developed acute graft rejection that proved resistant to conventional treatment. She was relisted and underwent re-transplantation along with kidney transplantation. Abdominal wall closure could not be achieved because of the large size of the graft and bowel oedema. The wound was initially managed with laparostomy followed by insertion of the delayed dynamic abdominal closure (DDAC) device (Abdominal Retraction Anchor - ABRA(®) system). Continuous dynamic traction to the wound edges resulted in gradual approximation and complete closure of the abdominal wound was achieved within 3 weeks. Successful abdominal closure after multivisceral transplantation or isolated intestinal transplantation often requires biological mesh, vascularised flaps or abdominal wall transplantation. DDAC eliminated the need for a prosthetic mesh or skin graft and provided an excellent cosmetic result. Adjustment of the dynamic traction at the bedside minimised the need for multiple returns to the operating theatre. It resulted in a well-healed linear scar without a hernia. Dynamic traction allows delayed closure of laparotomy resulting in strong and cosmetically sound wound healing with native tissue. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

  18. Thoracoscopic ASD closure is a reliable supplement for percutaneous treatment. (United States)

    Casselman, F P; Dom, H; De Bruyne, B; Vermeulen, Y; Vanermen, H


    To determine the feasibility and effectiveness of endoscopic atrial septal defect (ASD) closure when percutaneous ASD closure is impossible or has failed. Between March 1997 and February 2003, 74 patients (63% female, mean (SD) age 44 (16) years) underwent an endoscopic ASD closure. Median preoperative New York Heart Association functional class was I. Clinical and echocardiographic follow up was obtained for all patients (mean (SD) 38 (19) months). Patients were assessed for scar aesthetics, procedure related pain, functional recovery, and overall patient satisfaction. ASD closure was successful in all patients (two primum ASD, 68 secundum ASD, four sinus venosus type). Patch repair was performed in 42%. Mean aortic cross clamp and cardiopulmonary bypass times were 54 (24) minutes and 98 (35) minutes, respectively. There were no in-hospital deaths and no conversions to sternotomy. Complications included one iliac vein stenting, one femoral arterioplasty, two revisions for suspected bleeding, and seven cases of atrial fibrillation. Two patients required late reoperation: one for atrial thrombus and another for tricuspid regurgitation. Echocardiographic control confirmed complete ASD closure in 71 patients and a small residual shunt in three patients. Ninety three per cent of the patients were highly satisfied with very low procedure related pain and 97% felt they had an aesthetically pleasing scar. Endoscopic ASD closure can be safely done with a high degree of patient satisfaction. It is now the authors' exclusive surgical approach whenever percutaneous treatment is not indicated or has failed.

  19. A randomised controlled trial of absorbable versus non-absorbable sutures for skin closure after open carpal tunnel release.

    LENUS (Irish Health Repository)

    Theopold, C


    We compared the aesthetic outcome of scars after closure of open carpal tunnel incisions with either absorbable 4-0 Vicryl Rapide or non-absorbable 4-0 Novafil. Patients were recruited in a randomized controlled trial and scars were scored at 6 weeks using a modified Patient and Observer Scar Assessment Scale. Scores demonstrated differences only for pain, vascularity and cross-hatching between both groups, though none of these were statistically significant. The dissolving and falling out of Vicryl Rapide was significantly more comfortable than removal of 4-0 Novafil sutures, assessed on a numerical analogue scale. There was no difference in infection rate between both study groups, supporting overall the use of Vicryl Rapide for the closure of palmar hand incisions, in light of the convenience and cost savings associated with absorbable sutures.


    Energy Technology Data Exchange (ETDEWEB)



    This Closure Report (CR) describes the closure activities performed at CAU 528, Polychlorinated Biphenyls Contamination, as presented in the Nevada Division of Environmental Protection (NDEP)-approved Corrective Action Plan (CAP) (US. Department of Energy, National Nuclear Security Administration Nevada Site Office [NNSAINSO], 2005). The approved closure alternative was closure in place with administrative controls. This CR provides a summary of the completed closure activities, documentation of waste disposal, and analytical data to confirm that the remediation goals were met.

  1. An evaluation of immediate sheath removal and use of the Angio-Seal vascular closure device in neuroradiological interventions

    Energy Technology Data Exchange (ETDEWEB)

    Pierot, L. [Hopital Maison Blanche, Department of Radiology, Reims (France); Hopital Maison Blanche, Service de Radiologie, Reims (France); Herbreteau, D. [CHU, Department of Neuroradiology, Tours (France); Bracard, S. [CHU, Department of Diagnostic and Therapeutic Neuroradiology, Nancy (France); Berge, J. [CHU, Department of Neuroradiology, Bordeaux (France); Cognard, C. [Hopital Purpan, Department of Diagnostic and Therapeutic Neuroradiology, Toulouse (France)


    We set out to assess the effect of using an arteriotomy closure device in patients at high risk of access site complications. One-hundred nineteen patients with femoral artery access were prospectively included in five centers in France (56 males, 63 females, age range 20-84 years). The neurointerventional procedures were embolization of intracranial aneurysm (71.4%), carotid angioplasty (11.8%), cerebral angioplasty (1.7%), thrombolysis (0.8%), and other procedures (14.3%). Sheaths were removed and the closure device deployed immediately postprocedure. One patient developed a false aneurysm, and one developed a small hematoma. Neither required treatment. Postdevice deployment bleeding was experienced in three patients (2.5%), requiring minimal management. There were no major complications. Three patients died of causes unrelated to the vessel closure. Patient comfort was 2.2 on a scale of 1 (none) to 10 (severe). The results showed that immediate sheath removal followed by use of the closure device is safe in patients undergoing neurointerventional procedures and offers a low level of patient discomfort. In selected patients, early hospital discharge was possible. (orig.)

  2. 216-B-3 expansion ponds closure plan

    Energy Technology Data Exchange (ETDEWEB)


    This document describes the activities for clean closure under the Resource Conservation and Recovery Act of 1976 (RCRA) of the 216-B-3 Expansion Ponds. The 216-B-3 Expansion Ponds are operated by the US Department of Energy, Richland Operations Office (DOE-RL) and co-operated by Westinghouse Hanford Company (Westinghouse Hanford). The 216-B-3 Expansion Ponds consists of a series of three earthen, unlined, interconnected ponds that receive waste water from various 200 East Area operating facilities. The 3A, 3B, and 3C ponds are referred to as Expansion Ponds because they expanded the capability of the B Pond System. Waste water (primarily cooling water, steam condensate, and sanitary water) from various 200 East Area facilities is discharged to the Bypass pipe (Project X-009). Water discharged to the Bypass pipe flows directly into the 216-B-3C Pond. The ponds were operated in a cascade mode, where the Main Pond overflowed into the 3A Pond and the 3A Pond overflowed into the 3C Pond. The 3B Pond has not received waste water since May 1985; however, when in operation, the 3B Pond received overflow from the 3A Pond. In the past, waste water discharges to the Expansion Ponds had the potential to have contained mixed waste (radioactive waste and dangerous waste). The radioactive portion of mixed waste has been interpreted by the US Department of Energy (DOE) to be regulated under the Atomic Energy Act of 1954; the dangerous waste portion of mixed waste is regulated under RCRA.

  3. Wound closure of leg fasciotomy: comparison of vacuum-assisted closure versus shoelace technique. A randomised study. (United States)

    Kakagia, D; Karadimas, E J; Drosos, G; Ververidis, A; Trypsiannis, G; Verettas, D


    Fasciotomies, though essential for the prevention and management of compartment syndromes, may increase morbidity and prolong hospitalisation. Two widely applied methods of delayed primary closure are compared in leg fasciotomy wounds. Two groups, each of 25 patients with leg fasciotomies due to fractures and soft tissue injuries, who were randomly assigned to be treated either by vacuum assisted closure (VAC®, n=42 wounds, group V) or by the shoelace technique (n=40 wounds, group S), were evaluated in this study. Wound length, time to definite closure, complications, need for additional interventions and daily treatment costs were data collected and statistically assessed. Wound closure time was significantly higher in group V compared to group S (p=0.001; 95% CI of the difference, 1.8-6.3 days). Five group V patients required split thickness skin grafts. In six group S patients, the vessel loops had to be replaced. The mean daily cost of negative pressure therapy alone was 135 euro (range 117-144 euro), whilst the mean daily cost of treatment for the shoelace technique was 14 euro ranging from 8 to 18 euro (p=closure of leg fasciotomy wounds. VAC® requires longer time to definite wound closure and is far more expensive than the shoelace technique, especially when additional skin grafting is required. Copyright © 2012 Elsevier Ltd. All rights reserved.

  4. Association of iris crypts with acute primary angle closure. (United States)

    Koh, Victor; Chua, Jacqueline; Shi, Yuan; Thakku, Sri Gowtham; Lee, Ryan; Nongpiur, Monisha E; Baskaran, Mani; Kumar, Rajesh S; Perera, Shamira; Aung, Tin; Cheng, Ching-Yu


    To determine the relationship between iris surface features and acute primary angle closure (APAC) in eyes with angle closure. Case-control study involving Asian patients diagnosed with previous APAC, primary angle closure suspect (PACS), primary angle closure (PAC) and primary angle closure glaucoma (PACG) at an eye centre in Singapore between August 2012 and January 2015. Participants underwent ophthalmic examination and digital slit-lamp iris photography. Iris surface features were graded based on crypts, furrows and colour. Fellow eyes of APAC were compared with PACS and PAC/PACG eyes with regard to their iris surface features. Occurrence of APAC. A total of 309 patients (71 APAC, 139 PACS, 47 PAC and 52 PACG) were included (mean age: 67.7±7.2 years and 36.6% male). Compared with PACS, higher crypt grade was significantly associated with lower odds of APAC (OR=0.58 for one grade higher in crypt grade; p=0.027, adjusted for age, gender, ethnicity and pupil diameter). The results remained similar when compared with PAC/PACG group (OR=0.58 for one grade higher in crypt grade; p=0.043). We did not observe any significant associations between iris furrows or colour with presence of APAC. Our study comprising Asian eyes with angle closure suggests that the presence of a higher crypt grading may be protective for APAC. As such, assessing iris surface architecture for crypts could be a new measure for risk stratification of developing APAC in eyes with angle closure. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to

  5. Study of two techniques for midline laparotomy fascial wound closure. (United States)

    Gurjar, Vipul; Halvadia, B M; Bharaney, R P; Ajwani, Vicky; Shah, S M; Rai, Samir; Trivedi, Mitesh


    To study the results of two techniques, simple interrupted closure and continuous with intermittent Aberdeen knot technique for midline laparotomy fascial wound closure. A random selection of 200 midline laparotomy cases was done. In one group (group A) of 100 cases, midline fascial wound closure was done with continuous sutures with intermittent Aberdeen knot technique using Prolene No. 1 suture material. In the other group (group B) of 100 cases, closure was done with the technique of simple interrupted sutures with Prolene No.1 suture material. Comparison of both the techniques regarding preoperative status and postoperative complication such as incisional hernia, wound dehiscence, suture sinus formation, stitch granuloma, and chronic wound pain was done according to clinical examination and recorded in the pro forma prepared. In group A, postoperative complications were incisional hernia 3 %, wound dehiscence 4 %, and suture sinus formation 1 %. In group B, postoperative complication were incisional hernia 5 %, wound dehiscence 4 %, and suture sinus formation 1 %. All these complications were statistically insignificant, in both group comparisons. While the complication such as stitch granuloma 3 %, chronic wound pain 3 %, and wound infection 4 % in group A was significantly less than in group B where the complication of stitch granuloma was 12 %, chronic wound pain 13 %, and wound infection 13 % (P value 0.03, P value 0.018, and P value 0.048, respectively). Both the techniques, simple interrupted suture closure and continuous with intermittent Aberdeen knot closure for midline laparotomy fascial wounds, show a similar rate of postoperative complication such as incisional hernia, wound dehiscence, and suture sinus formation. But the continuous suturing with intermittent Aberdeen knot technique is a better option to prevent complications such as stitch granuloma, chronic wound pain, and wound infection, which are higher in the simple interrupted

  6. Single-shell tank closure work plan. Revision A

    Energy Technology Data Exchange (ETDEWEB)



    In January 1994, the Hanford Federal Facility Agreement and Conset Order (Tri-Party Agreement) was amended to reflect a revised strategy for remediation of radioactive waste in underground storage tanks. These amendments include milestones for closure of the single-shell tank (SST) operable units, to be initiated by March 2012 and completed by September 2024. This SST-CWP has been prepared to address the principal topical areas identified in Tri-Party Agreement Milestone M-45-06 (i.e., regulatory pathway, operable unit characterization, waste retrieval, technology development, and a strategy for achieving closure). Chapter 2.0 of this SST-CWP provides a brief description of the environmental setting, SST System, the origin and characteristics of SST waste, and ancillary equipment that will be remediated as part of SST operable unit closure. Appendix 2A provides a description of the hydrogeology of the Hanford Site, including information on the unsaturated sediments (vadose zone) beneath the 200 Areas Plateau. Chapter 3.0 provides a discussion of the laws and regulations applicable to closure of the SST farm operable units. Chapter 4.0 provides a summary description of the ongoing characterization activities that best align with the proposed regulatory pathway for closure. Chapter 5.0 describes aspects of the SST waste retrieval program, including retrieval strategy, technology, and sequence, potential tank leakage during retrieval, and considerations of deployment of subsurface barriers. Chapter 6.0 outlines a proposed strategy for closure. Chapter 7.0 provides a summary of the programs underway or planned to develop technologies to support closure. Ca. 325 refs.

  7. Patent foramen ovale closure to prevent secondary neurologic events. (United States)

    Jasper, Rosie; Blankenship, James C


    In October of 2016 the United States Food and Drug Administration approved the Amplatzer Patent Foramen Ovale (PFO) occluder device for use in patients with cryptogenic stroke, to reduce the risk of recurrent stroke. This event followed 15years of off-label use of atrial septal occluder devices, 3 randomized trials, and enormous controversy over the efficacy of this procedure. While none of the trials reached the primary endpoint needed to prove the efficacy of PFO closure in preventing recurrent stroke, meta-analyses and 5-year follow-up of 1 trial suggest that PFO closure decreases the risk of recurrent stroke, especially in sub-groups with large shunts and atrial septal aneurysms, and especially when the Amplatzer device (rather than other devices) is used. While the relative reduction in stroke associated with PFO closure is large (about 50%), the absolute reduction is low (1-2%) and must be balanced against complications of the procedure (about 3%). Thus, PFO closure is restricted to patients with cryptogenic stroke, and depends heavily on patients' personal preferences. Uncertainties about the etiology of stroke in patients with PFO and the efficacy of PFO closure cause a difficult problem for the internal medicine specialist. At one extreme the internist may wonder if every patient with a documented PFO should be referred to a cardiologist. At the other extreme, supported by specialty society guidelines, internists may conclude that PFO closure is rarely necessary. In this paper we review the current status of PFO closure and suggest a rational strategy for this procedure. Copyright © 2017 European Federation of Internal Medicine. Published by Elsevier B.V. All rights reserved.

  8. Comparison of surgical techniques for stoma closure: A retrospective study of purse-string skin closure versus conventional skin closure following ileostomy and colostomy reversal (United States)



    The aim of this study was to compare the incidence of postoperative complications, including superficial incisional surgical site infection (SSI) following purse-string skin closure (PS) and conventional skin closure with a drainage tube (CD) following stoma closure. A total of 55 consecutive patients who underwent loop colostomy and loop ileostomy closures in our hospital between October, 2011 and September, 2014 were retrospectively assessed. The patients were divided into two groups, namely the PS group (26 patients) and the CD group (29 patients). There were no significant differences in the characteristics of the patients between the two groups. The baseline and operative characteristics also did not differ significantly between the two groups. However the incidence of superficial incisional SSI was lower in the PS group compared to that in the CD group (0 vs. 13.8%, respectively; P=0.049). The overall incidence of complications did not differ significantly between the two groups (P=0.313). The duration of postoperative hospital stay in the PS group was shorter compared to that in the CD group. In conclusion, the results of this study suggest that PS may an effective technique to reduce the incidence of superficial incisional SSI. This technique appears to be superior to the conventional technique, allowing for better cosmesis. PMID:26137277

  9. Plateau iris in Japanese patients with primary angle closure and primary angle closure glaucoma

    Directory of Open Access Journals (Sweden)

    Mizoguchi T


    Full Text Available Takanori Mizoguchi,1 Mineo Ozaki,2,3 Harumi Wakiyama,1,4 Nobuchika Ogino1,51Mizoguchi Eye Clinic, Nagasaki, Japan; 2Ozaki Eye Clinic Miyazaki, Japan; 3Department of Ophthalmology, Faculty of Medicine, University of Miyazaki, Miyazaki, Japan; 4The Japanese Red Cross Nagasaki Genbaku Hospital, Nagasaki, Japan; 5Nishigaki Eye Clinic, Nagoya, JapanPurpose: To determine the prevalence of plateau iris in Japanese patients with primary angle closure (PAC and primary angle closure glaucoma (PACG and analyze the biometric parameters in patients with plateau iris using ultrasound biomicroscopy (UBM.Methods: In this cross-sectional observational study, subjects aged >50 years with PAC and PACG who had previously undergone a patent laser peripheral iridotomy underwent UBM in one eye. UBM images were qualitatively analyzed using standardized criteria. Plateau iris in a quadrant was defined by anteriorly directed ciliary body, absent ciliary sulcus, steep iris root from its point of insertion followed by a downward angulation, flat iris plane, and irido-angle contact. At least two quadrants had to fulfill these UBM criteria for an eye to be classified as having plateau iris. A-scan biometry was used to measure anterior segment parameters.Results: Ninety-one subjects with PAC (58 subjects or PACG (33 subjects and 68 normal controls were recruited. The mean (standard deviation ages of PAC and PACG patients and normal controls were 73.5 (6.2 and 72.6 (7.3, respectively. Based on UBM criteria, plateau iris was found in 16 eyes (17.6% of 91 eyes. In these 16 eyes, quadrant-wise analysis showed ten eyes (62.5% had plateau iris in two quadrants; four eyes (25% had plateau iris in three quadrants; and two eyes (12.5% had plateau iris in four quadrants. Anterior chamber depth, lens thickness, axial length, lens position, and relative lens position were not statistically significant between the group having plateau iris and that not having plateau iris

  10. Long-term cavity closure in non-linear rocks (United States)

    Cornet, Jan; Dabrowski, Marcin; Schmid, Daniel Walter


    The time dependent closure of pressurized cavities in viscous rocks due to far-field loads is a problem encountered in many applications like drilling, cavity abandonment and porosity closure. The non-linear nature of the flow of rocks prevents the use of simple solutions for hole closure and calls for the development of appropriate expressions reproducing all the dependencies observed in nature. An approximate solution is presented for the closure velocity of a pressurized cylindrical cavity in a non-linear viscous medium subjected to a combined pressure and shear stress load in the far field. The embedding medium is treated as homogeneous, isotropic, and incompressible and follows a Carreau viscosity model. We derive analytical solutions for the end-member cases of the pressure and shear loads. The exact analytical solution for pressure loads shows that the closure velocity vR is given by the implicit expression {Δ p}/{2{μ _0D_{II}^*}} = - 1/2B( {v_R^2}/{RD_{II^* + v_R^2}};1/2, - 1/{2n}} ), where Δp is the pressure load, R is the hole radius, B is the incomplete beta function, and μ0, D_{II}^*, n are, respectively, the threshold viscosity, transition rate and stress exponent of the Carreau model. The closure velocity is dominated by the linear mechanism under pressure loads smaller than 1.8{μ _0}D_{II}^* and by the non-linear one under large pressure loads. In the non-linear regime, pressure variations support an increasing part of the load with increasing degree of non-linearity. The decay of the stress perturbation in the non-linear zone varies as r- 2/n where r is the radial distance to the hole. A solution for the maximum closure velocity at the cavity rim vRmax under far-field shear is given: v_{R\\max} = ( {1 + {\\overline {M_s}}^{-1/2})R\\overline D_{II}, where \\overline M_s = (1 +{\\overline{D_{II}}^2} \\big nD_{II}^*^2} ) \\big ( 1 + {\\overline {D_{II}}^2} \\big D{_{II}^*}^2 ) and \\overline D_{II} is the second invariant of the far

  11. Fatigue testing of three peristernal median sternotomy closure techniques

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    Griffin Lanny V


    Full Text Available Abstract Background Failure of a sternotomy closure because of closure system fatigue is a complication that may result in dehiscence and put the individual at risk for serious complications. The purpose of this study was to assess the fatigue performance of three peristernal median sternotomy closure techniques (figure-of-eight stainless-steel wires, figure-of-eight stainless-steel cables, or Pectofix Dynamic Sternal Fixation [DSF] stainless-steel plates in order to quantify the potential risk of fatigue failure of these devices when subject to cyclic loads in physiologically relevant loading directions. Study Design All tests were conducted on polyurethane foam sternal models. A cardiothoracic surgeon divided each sternal model longitudinally and repaired it with a closure device. Tests were performed using a materials testing system that applied cyclic loading in a uniaxial direction until the test model catastrophically broke or data run-out occurred. For each loading direction (lateral distraction and longitudinal shear, five trials of each closure technique were tested. Life data and location of device failure (if present were evaluated. Statistical analysis was performed using regression with life data allowed for correlation between life data and the various closure techniques to develop risk assessment curves for each device. Results The data show that the figure-of-eight stainless-steel cable and the DSF plate systems are considerably less likely to fail under both lateral distraction and longitudinal shear cyclic loading conditions as compared to the figure-of-eight stainless-steel wire system. Moreover, the figure-of-eight stainless-steel cable system is the most resistant to failure, particularly for high cycle counts. Conclusion This study in addition to Cohen and Griffin's earlier published biomechanical comparison of the ultimate strength of these same three closure techniques provide extensive experimental evidence regarding the

  12. The impact of rolling theatre closures on core urology training. (United States)

    Good, D W; Khan, N; Kiely, E; Brady, C


    Since 2008, government funding of the Health Service Executive (HSE) has decreased significantly. Our hospital, Cork University Hospital (CUH), implemented "cost saving" measures including scheduled operating theatre closures. We studied their affect on urological surgical activity at the hospital. A retrospective review was performed using theatre log books and theatre records to determine the number, type and training status of procedures performed for years 2009 and 2011. Scheduled theatre closures in 2011 resulted in 33 more theatre session cancelations compared to 2009. There was a reduction in the total number of procedures performed from 555 cases in 2009 to 443 in 2011 a 20.2(%) reduction. The number of "training" cases reduced from 325 (58.9%) in 2009 to 216 (48.7%) in 2011 a 10.2% reduction (Table 2). Eight out of the nine "core urology training" procedures reduced in number from 2009 to 2011 (Table 1). We have shown that scheduled theatre closures have reduced the number of procedures performed and have impacted on urology training. Scheduled theatre closures are expected to become more frequent in the future. Potential solutions to lessen the impact include providing simulation training using the Royal College of Surgeons in Ireland (RCSI) mobile skills unit during these theatre closures.

  13. Design, production and initial state of the closure

    Energy Technology Data Exchange (ETDEWEB)


    The report is included in a set of Production reports, presenting how the KBS-3 repository is designed, produced and inspected. The production reports are included in the safety report for the KBS-3 repository and repository facility. The report provides input on the initial state of the closure and plugs in underground openings other than deposition tunnels for the assessment of the long-term safety, SR-Site. The initial state refers to the properties of the engineered barriers once they have been finally placed in the KBS-3 repository and will not be further handled within the repository facility. In addition, the report provides some input to the operational safety report, SR-Operation, on how the closure and plugs shall be handled and installed. The report presents the design premises and reference designs of the closure and plugs and verifies their conformity to the design premises. It also briefly deals with the production of the closure and plugs. Finally, the initial state of the closure and plugs and their conformity to the reference designs and design premises are presented

  14. A novel option of uninterrupted closure of surgical wounds

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    Sulamanidze Marlen


    Full Text Available Background : A cosmetically pleasing postoperative scar is an important aim of all aesthetic surgeries. Use of proper suture materials for delicate and gentle suturing of the operative injury is an important requirement for achieving satisfactory scars. However, closure of the edges of wounds by means of conventional suture materials does not always meet the requirements to achieve this objective. Aim : To simplify and facilitate the process of surgical wound closure, to improve the quality of scar, and to achieve a good cosmetic effect through the introduction of a new type of suture material. Materials and Methods : We have introduced a new surgical suturing material-a nontraumatic, barbed thread connected with the suture needle-APTOS SUTURE (European patent 1075843 as of 1999. Presented herein is a new modification of the technique of uninterrupted subcutaneous and intracutaneous suturing of wound edges, and the details of our experience with this material. Results : Our experience shows that, with use of APTOS, wound closure is carried out easily and quickly. The wound remains stable, the time of healing is shortened, and the process of suture removal is simplified, resulting in an aesthetically pleasing scar. Conclusions : The technique of surgical wound suturing proposed herein is a simple, facilitated, and efficient option of wound-edge closure, which can successfully be used, both in general and in aesthetic surgery for wound closure, such as plasty of scars, face lift, mammoplasty, and abdominal plasty.

  15. Experimental investigation on the pressure characteristics of cavity closure region (United States)

    Wang, Yadong; Yuan, Xulong; Zhang, Yuwen


    The most complicated component in cavitating flow and pressure distribution is the flow in the cavity closure line. The cavitating flow and pressure distribution provide critical aspects of flow field details in the region. The integral of pressure results of the hydrodynamic forces, indicate domination in the design of a supercavitating vehicle. An experiment was performed in a water tunnel to investigate the pressure characteristics of the cavity closure region. Ventilation methods were employed to generate artificial cavity, and the ventilation rate was adjusted accordingly to obtain the desired cavity length. An array of pressure transducers was laid down the cavity closure line to capture pressure distribution in this region. The experimental results show that there is a pressure peak in the cavity closure region, and the rise rate of pressure in space tends to be higher in the upwind side when the flow is non-axisymmetric. The transient pressure variations during the cavity formation procedure were also present. The method of measurement in this paper can be referenced by engineers. The result helps to study the flow pattern of cavity closure region, and it can also be used to analyze the formation of supercavitating vehicle hydrodynamics.

  16. Cutaneous wound closure materials: An overview and update

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    Luluah Al-Mubarak


    Full Text Available Introduction: On a daily basis, dermasurgeons are faced with different kinds of wounds that have to be closed. With a plethora of skin closure materials currently available, choosing a solution that combines excellent and rapid cosmetic results with practicality and cost-effectiveness can be difficult, if not tricky. Objectives: We aimed to review the available skin closure materials over the past 20 years and the scientific claims behind their effectiveness in repairing various kinds of wounds. Materials and Methods: The two authors independently searched and scrutinised the literature. The search was performed electronically using Pub Med, the Cochrane Database, Google Scholar and Ovid as search engines to find articles concerning skin closure materials written since 1990. Conclusion: Many factors are involved in the choice of skin closure material, including the type and place of the wound, available materials, physician expertise and preferences, and patient age and health. Evidence-based main uses of different skin closure materials are provided to help surgeons choose the appropriate material for different wounds.

  17. Effectiveness of percutaneous closure of patent foramen ovale for hypoxemia. (United States)

    Fenster, Brett E; Nguyen, Bryant H; Buckner, J Kern; Freeman, Andrew M; Carroll, John D


    The aim of this study was to evaluate the ability of percutaneous patent foramen ovale (PFO) closure to improve systemic hypoxemia. Although PFO-mediated right-to-left shunt (RTLS) is associated with hypoxemia, the ability of percutaneous closure to ameliorate hypoxemia is unknown. Between 2004 and 2009, 97 patients who underwent PFO closure for systemic hypoxemia and dyspnea that was disproportionate to underlying lung disease were included for evaluation. All patients exhibited PFO-mediated RTLS as determined by agitated saline echocardiography. Procedural success was defined as implantation of a device without major complications and mild or no residual shunt at 6 months. Clinical success was defined as a composite of an improvement in New York Heart Association (NYHA) functional class, reduction of dyspnea symptoms, or decreased oxygen requirement. Procedural success was achieved in 96 of 97 (99%), and clinical success was achieved in 68 of 97 (70%). The presence of any moderate or severe interatrial shunt by agitated saline study (odds ratio [OR] = 4.7; p gender (OR = 0.30; p <0.017) decreased the likelihood of success. In conclusion, based on the largest single-center experience of patients referred for PFO closure for systemic hypoxemia, PFO closure was a mechanically effective procedure with an associated improvement in echocardiographic evidence of RTLS, NYHA functional class, and oxygen requirement. Copyright © 2013 Elsevier Inc. All rights reserved.

  18. Patent foramen ovale closure and migraine: science and sensibility. (United States)

    Gupta, Vinod Kumar


    Migraine has been associated with patent foramen ovale (PFO), and PFO closure has become the most high-profile nonpharmacologic invasive therapy recommended for the prevention of recurrent migraine attacks, as well as for preventing further attacks in cryptogenic stroke. The results of Migraine Intervention with STARFlex Technology (MIST), a controversial but important recent randomized clinical trial (RCT) of PFO closure for migraine, do not support PFO closure for preventing migraine attacks. All patients with migraine, however, do not have a PFO, and the characteristic periodicity and predictability of migraine cannot be explained on the basis of paradoxical embolism through the PFO. Closure of the PFO or atrial septal defect can aggravate migraine suddenly. PFO increases in size with age, but migraine generally subsides with the passage of years. Serendipity does play a role in some medical discoveries, but in the absence of a logically defensible theoretical basis, chance and statistics can both become misleading. With soft end points, RCTs in migraine patients can generate conflicting and irreconcilable data. RCTs cannot supplant or substitute clinical common sense or justify serendipity. Scientific progress mandates that any serendipitous research must ultimately conform to the principles of the basic sciences surrounding the chance discovery. PFO closure for preventing migraine attacks is an unfortunate, but sobering, chapter in the migraine research saga.

  19. Plateau iris in Japanese patients with primary angle closure and primary angle closure glaucoma. (United States)

    Mizoguchi, Takanori; Ozaki, Mineo; Wakiyama, Harumi; Ogino, Nobuchika


    To determine the prevalence of plateau iris in Japanese patients with primary angle closure (PAC) and primary angle closure glaucoma (PACG) and analyze the biometric parameters in patients with plateau iris using ultrasound biomicroscopy (UBM). In this cross-sectional observational study, subjects aged >50 years with PAC and PACG who had previously undergone a patent laser peripheral iridotomy underwent UBM in one eye. UBM images were qualitatively analyzed using standardized criteria. Plateau iris in a quadrant was defined by anteriorly directed ciliary body, absent ciliary sulcus, steep iris root from its point of insertion followed by a downward angulation, flat iris plane, and irido-angle contact. At least two quadrants had to fulfill these UBM criteria for an eye to be classified as having plateau iris. A-scan biometry was used to measure anterior segment parameters. Ninety-one subjects with PAC (58 subjects) or PACG (33 subjects) and 68 normal controls were recruited. The mean (standard deviation) ages of PAC and PACG patients and normal controls were 73.5 (6.2) and 72.6 (7.3), respectively. Based on UBM criteria, plateau iris was found in 16 eyes (17.6%) of 91 eyes. In these 16 eyes, quadrant-wise analysis showed ten eyes (62.5%) had plateau iris in two quadrants; four eyes (25%) had plateau iris in three quadrants; and two eyes (12.5%) had plateau iris in four quadrants. Anterior chamber depth, lens thickness, axial length, lens position, and relative lens position were not statistically significant between the group having plateau iris and that not having plateau iris, respectively. Approximately 20% of Japanese subjects with PAC and PACG with a patent laser peripheral iridotomy were found to have plateau iris on UBM. No morphological difference was noted in the anterior segment of the eye between those with or without plateau iris.

  20. Quality of Life and Timing of Stoma Closure in Patients With Rectal Cancer Undergoing Low Anterior Resection With Diverting Stoma: A Multicenter Longitudinal Observational Study. (United States)

    Herrle, Florian; Sandra-Petrescu, Flavius; Weiss, Christel; Post, Stefan; Runkel, Norbert; Kienle, Peter


    After low anterior resection for rectal cancer, creation of a diverting stoma is recommended. Data on the impact of a diverting stoma on quality of life are conflicting. Optimal timing of stoma closure in the setting of adjuvant chemotherapy is unclear. The purpose of this study was to investigate the impact of a diverting stoma on quality of life in patients undergoing rectal cancer resection before and after stoma closure. Furthermore, the study was conducted to look at the timing of stoma reversal and the potential influence of factors such as adjuvant chemotherapy. This was a longitudinal, observational, multicenter study. The study was conducted at 17 German colorectal centers. Patients with rectal cancer who planned for elective curative surgery with creation of temporary diverting stoma were included. This longitudinal observational study assessed quality of life at 3 occasions using European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire-Core Questionnaire/Colorectal Cancer Module before cancer resection, before stoma closure, and 6 months after stoma closure. Furthermore, the timing of stoma closure and continence were evaluated. A total of 120 patients (64% men; mean age, 63.2 ± 11.5 years) were analyzed. Longitudinal global quality of life was not influenced by the presence of a stoma. Several functional and GI symptom scales were markedly impaired after stoma creation. Physical, role functioning, and sexual interest recovered after stoma closure. Social functioning stayed impaired (p stoma closure was 5 months (range, 17 days to 18 months). A total of 3.4% of patients had very early stoma closure (within 30 days). Adjuvant chemotherapy delayed stoma closure (median, 5.6 vs 3.4 months without chemotherapy; p = 0.0001). The study was limited by its missing quality-of-life data for sexual function. The presence of a stoma had a negative impact on social functioning and GI symptoms. However, this had no clinically relevant

  1. Pursestring Closure versus Conventional Primary Closure Following Stoma Reversal to Reduce Surgical Site Infection Rate: A Meta-analysis of Randomized Controlled Trials. (United States)

    Hsieh, Meng-Chiao; Kuo, Liang-Tseng; Chi, Ching-Chi; Huang, Wen-Shih; Chin, Chih-Chien


    Stoma reversal is a surgical procedure commonly used following temporary defunctioning stoma surgery. Surgical site infection is one of the most common postoperative morbidities. A few skin closure methods have been developed to decrease surgical site infection. However, the optimal skin closure method is still in debate. The aim of this study was to compare the surgical site infection rate and other postoperative outcomes between the pursestring closure and conventional primary closure techniques. We searched the MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials for relevant trials. We conducted a meta-analysis of randomized controlled trials that compared the surgical outcomes following pursestring closure and conventional primary closure techniques. We conducted the meta-analysis by using the random-effects model. The primary outcome of interest was surgical site infection following stoma reversal within 30 days after operation. This meta-analysis included 4 randomized controlled trials with a total of 319 participants (162 in the pursestring closure group and 157 in the conventional primary closure group). Compared with the conventional primary closure group, the pursestring closure group had a significant decrease in surgical site infection (risk difference, -0.25; 95% CI, -0.36 to -0.15; p stoma reversal than conventional primary closure.

  2. Randomized clinical trial of intestinal ostomy takedown comparing pursestring wound closure vs conventional closure to eliminate the risk of wound infection. (United States)

    Camacho-Mauries, Daniel; Rodriguez-Díaz, José Luis; Salgado-Nesme, Noel; González, Quintín H; Vergara-Fernández, Omar


    The use of temporary stomas has been demonstrated to reduce septic complications, especially in high-risk anastomosis; therefore, it is necessary to reduce the number of complications secondary to ostomy takedowns, namely wound infection, anastomotic leaks, and intestinal obstruction. To compare the rates of superficial wound infection and patient satisfaction after pursestring closure of ostomy wound vs conventional linear closure. Patients undergoing colostomy or ileostomy closure between January 2010 and February 2011 were randomly assigned to linear closure (n = 30) or pursestring closure (n = 31) of their ostomy wound. Wound infection within 30 days of surgery was defined as the presence of purulent discharge, pain, erythema, warmth, or positive culture for bacteria. Patient satisfaction, healing time, difficulty managing the wound, and limitation of activities were analyzed with the Likert questionnaire. The infection rate for the control group was 36.6% (n = 11) vs 0% in the pursestring closure group (p ostomy wound closure (shorter healing time and improved patient satisfaction).

  3. Complications of Transcatheter Closure in Patent Ductus Arteriosus Patients

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    Faranak Behnaz


    Full Text Available Background: Published studies have shown excellent success rates and also low rates of life-threatening complications with trans-catheter closure of patent ductus arteriosus (PDA. However, most studies to date have been conducted in developed nations and reports from developing countries such as Iran are lacking. Objectives: To report our experience with trans-catheter closure of patent ductus arteriosus (PDA and compare two devices and complications. Patients and Methods: From 2007 to 2011, 72 consecutive PDA cases were prospectively enrolled. For PDAs ≤ 2 mm, the coiling method was employed whereas patients with PDA > 2 mm received Amplatzer duct occlusion (ADO. Success was defined as trivial residual shunt ( 0.05. Conclusions: Excellent and comparable success rates for both closure techniques were observed and no major complications were observed.

  4. INTEC CPP-603 Basin Water Treatment System Closure: Process Design

    Energy Technology Data Exchange (ETDEWEB)

    Kimmitt, Raymond Rodney; Faultersack, Wendell Gale; Foster, Jonathan Kay; Berry, Stephen Michael


    This document describes the engineering activities that have been completed in support of the closure plan for the Idaho Nuclear Technology and Engineering Center (INTEC) CPP-603 Basin Water Treatment System. This effort includes detailed assessments of methods and equipment for performing work in four areas: 1. A cold (nonradioactive) mockup system for testing equipment and procedures for vessel cleanout and vessel demolition. 2. Cleanout of process vessels to meet standards identified in the closure plan. 3. Dismantlement and removal of vessels, should it not be possible to clean them to required standards in the closure plan. 4. Cleanout or removal of pipelines and pumps associated with the CPP-603 basin water treatment system. Cleanout standards for the pipes will be the same as those used for the process vessels.

  5. Percutaneous left atrial appendage closure for stroke prevention

    DEFF Research Database (Denmark)

    De Backer, Ole; Loupis, Anastasia M; Ihlemann, Nikolaj


    INTRODUCTION: In atrial fibrillation (AF) patients with an increased stroke risk, oral anticoagulation (OAC) is the standard treatment for stroke prevention. However, this therapy carries a high risk of major bleeding. Percutaneous closure of the left atrial appendage (LAA) is suggested...... as an alternative option for stroke prevention in AF patients with contraindication(s) for OAC treatment. MATERIAL AND METHODS: A total of 42 patients underwent percutaneous LAA closure. In this report, we describe our experience with this procedure. RESULTS: The patients treated were AF patients with a high stroke...... risk (CHADS-VASc 4.5±1.4) and contra-indication(s) for OAC and/or a high bleeding risk (HAS-BLED 3.7±0.9). A history of intracerebral bleeding was the most common reason for LAA closure. Successful implantation was obtained in 41 of 42 patients. One major peri-procedural complication occurred; a major...

  6. Percutaneous paravalvular leak closure- imaging, techniques and outcomes. (United States)

    Krishnaswamy, Amar; Kapadia, Samir R; Tuzcu, E Murat


    Paravalvular leak (PVL) is a known complication of surgical and transcatheter valve replacement procedures. Patients most commonly present with congestive heart failure and/or hemolysis, and repeat surgical procedures to correct the PVL carries increased risk with reduced likelihood of success. As a result, percutaneous approaches to PVL closure have been developed, with a considerable emphasis on multimodality imaging for both diagnosis and procedural guidance in the cardiac catheterization laboratory. Several large series of percutaneous PVL closure have been recently published, with encouraging results with respect to both procedural success and clinical outcomes. Here, we give a comprehensive review of imaging and procedural techniques for percutaneous PVL closure and present the data supporting this novel treatment strategy.

  7. Safety Outcomes After Percutaneous Transcatheter Closure of Patent Foramen Ovale. (United States)

    Merkler, Alexander E; Gialdini, Gino; Yaghi, Shadi; Okin, Peter M; Iadecola, Costantino; Navi, Babak B; Kamel, Hooman


    We sought to evaluate the real-world rate of safety outcomes after patent foramen ovale (PFO) closure in patients with ischemic stroke or transient ischemic attack (TIA). We performed a retrospective cohort study using administrative claims data on all hospitalizations from 2005 to 2013 in New York, California, and Florida. Using International Classification of Diseases, Ninth Revision, Clinical Modification codes, we identified patients who underwent percutaneous transcatheter PFO closure within 1 year of ischemic stroke or TIA. Our outcome was an adverse event occurring during the hospitalization for PFO closure, defined as in prior studies as atrial fibrillation or flutter, cardiac tamponade, pneumothorax, hemothorax, a vascular access complication, or death. Crude rates were reported with exact confidence intervals. We identified 1887 patients who underwent PFO closure after ischemic stroke or TIA. The rate of any adverse outcome during the hospitalization for PFO closure was 7.0% (95% confidence interval [CI], 5.9%-8.2%). Rates of adverse outcomes varied by age and type of preceding cerebrovascular event. In patients >60 years of age, the rate of adverse outcomes was 10.9% (95% CI, 8.6%-13.6%) versus 4.9% (95% CI, 3.8%-6.3%) in patients ≤60 years of age. The rate of adverse outcomes was 9.9% (95% CI, 7.3%-12.5%) in patients with preceding ischemic stroke versus 5.9% (95% CI, 4.7%-7.1%) after TIA. Approximately 1 in 14 patients who underwent percutaneous transcatheter PFO closure after ischemic stroke or TIA experienced a serious periprocedural adverse outcome or death. The risk of adverse outcomes was highest in older patients and in those with preceding ischemic stroke. © 2017 American Heart Association, Inc.

  8. Amplatzer duct occluder II for closure of congenital Gerbode defects. (United States)

    Vijayalakshmi, I B; Natraj Setty, H S; Chitra, Narasimhan; Manjunath, Cholenahally N


    Congenital left ventricle to right atrial communications (Gerbode defects) are extremely rare (0.08%) type of ventricular septal defects. They were traditionally closed by surgery in the past. There are few case reports and small series of acquired and congenital Gerbode defects, closed with various types of devices. Aim of our study is to assess the feasibility, efficacy, and complications of transcatheter closure of congenital Gerbode defects with Amplatzer duct occluder II (ADO II). Twelve consecutive cases of Gerbode defects, age ranging from 10 months to 16 years (mean 6.7 years), weight ranging from 6.5 kg to 34 kg (mean 19.3 kg), were diagnosed on transthoracic echocardiography. Transcatheter closure of Gerbode defects was done successfully through retrograde approach with ADO II. No aortic or tricuspid regurgitation or residual shunt occurred in any of the patients. One patient developed transient complete heart block needing temporary pacing. The soft low profile, easily trackable ADO II appears to be ideal for closure of Gerbode defects, as the central cylinder fits in the defect and the soft retention discs on either side, without polyester material, do not impinge on either aortic, mitral, or tricuspid valve. We report the successful transcatheter closure of twelve cases of congenital Gerbode defects with ADO II. Transcatheter closure of congenital Gerbode defects with ADO II is safe, effective, and an attractive alternative to surgical closure. ADO II appears to be tailor made for Gerbode defects, as the success rate is very high and complication rate is very low. © 2015 Wiley Periodicals, Inc.

  9. Vacuum-assisted closure system in treatment of postoperative mediastinitis. (United States)

    Elawadi, Mohamed Ahmed; Oueida, Farouk


    Post-cardiac surgery mediastinitis is a serious complication with high morbidity and high financial costs. Using a vacuum-assisted closure system is the established line of treatment for mediastinitis, which improves outcome, especially in the high-risk group of patients. From January 2007 to April 2011, a retrospective study was carried out to evaluate the outcome of vacuum-assisted closure in the treatment of postoperative mediastinitis. There were 34 patients; 27 were male and 7 female. Mean time from infection to vacuum-assisted closure was 3.34 ± 1.10 days. The duration of vacuum-assisted closure was 6.51 ± 1.85 days (3-9 days). The mean amount of discharge was 759.60 ± 175.28 mL (range, 354-990 mL). Of the 34 patients, 21 (61.76%) had direct surgical wound closure and 13 (41.16%) had re-wiring. Two patients had bilateral pectoral flaps. One patient had chronic fistula formation, and one had a tear in the right ventricle. Mean hospital stay was 11.28 ± 2.09 days (range, 6-16 days). Vacuum-assisted closure therapy is a safe, reliable, and cost-effective modality of treatment for postoperative mediastinitis. It improves the outcome and can be combined with other modalities of conventional treatment, especially in high-risk groups such as the elderly or patients with diabetes.

  10. Morbidity after closure of a defunctioning loop ileostomy. (United States)

    D'Haeninck, A; Wolthuis, A M; Penninckx, F; D'Hondt, M; D'Hoore, A


    A low pelvic anastomosis is associated with a substantial risk of leakage. A defunctioning stoma (DS) reduces the clinical anastomotic leak rate and the need for re-operation, but stoma closure has its own risk of morbidity and mortality. This study aims to audit morbidity and mortality after loop ileostomy (LI) closure. The medical records of 197 consecutive patients who underwent closure of a defunctioning LI between August 2003 and July 2008 were reviewed. Postoperative morbidity and mortality were recorded. Transverse closure of the enterotomy was performed in 149 patients (75.6%), segmental enterectomy with hand-sewn end-to-end anastomosis in 26 (13.2%) and stapled side-to-side anastomosis in 22 (11.2%). Overall postoperative morbidity and mortality were 32.0% and 0.5%, respectively. The surgical complication rate was 30.5%, including prolonged ileus (11.2%), small bowel obstruction (4.1%), anastomotic leak (3.0%) and wound infection (4.6%). Surgical complications were more frequent in male patients (p = 0.005). Prolonged ileus was more frequent when the interval to stoma reversal exceeded 12 weeks (14.3% versus 3.5% ; p = 0.02). The incidence of complications was not influenced by the closure technique. Nineteen patients (9.6%) required re-operation for anastomotic leak (n = 8), wound infection (n = 1), small bowel obstruction (n = 3) and incisional herniation (n = 7). LI closure is associated with clinically relevant morbidity and mortality. This association should be taken into account in the context of a routine DS policy and should be part of the patient's information.

  11. A PDF closure model for compressible turbulent chemically reacting flows (United States)

    Kollmann, W.


    The objective of the proposed research project was the analysis of single point closures based on probability density function (pdf) and characteristic functions and the development of a prediction method for the joint velocity-scalar pdf in turbulent reacting flows. Turbulent flows of boundary layer type and stagnation point flows with and without chemical reactions were be calculated as principal applications. Pdf methods for compressible reacting flows were developed and tested in comparison with available experimental data. The research work carried in this project was concentrated on the closure of pdf equations for incompressible and compressible turbulent flows with and without chemical reactions.

  12. Pulmonary edema following transcatheter closure of atrial septal defect

    Directory of Open Access Journals (Sweden)

    Keerthi Chigurupati


    Full Text Available We describe an incident of development of acute pulmonary edema after the device closure of a secundum atrial septal defect in a 52-year-old lady, which was treated with inotropes, diuretics and artificial ventilation. Possibility of acute left ventricular dysfunction should be considered after the defect closure in the middle-aged patients as the left ventricular compliance may be reduced due to increased elastic stiffness and diastolic dysfunction. Baseline left atrial pressure may be > 10 mmHg in these patients. Associated risk factors for the left ventricular dysfunction are a large Qp:Qs ratio, systemic hypertension, severe pulmonary hypertension and paroxysmal atrial fibrillation.

  13. Cataract surgery and methods of wound closure: a review

    Directory of Open Access Journals (Sweden)

    Matossian C


    Full Text Available Cynthia Matossian,1 Sarah Makari,2 Richard Potvin2 1Matossian Eye Associates, Pennington, NJ, 2Science in Vision, Akron, NY, USA Abstract: Clear corneal incisions are routinely used in cataract surgery, but watertight wound closure may not always be achieved, which can increase the risk for anterior chamber fluid egress or ocular surface fluid ingress. A new US Food and Drug Administration-approved ocular sealant appears to have good efficacy in sealing clear corneal incisions; its use may be indicated when wound integrity is in question. Keywords: clear corneal incisions, wound closure, sealant, suture, stromal hydration, cataract surgery

  14. Splinting with diastema closure as an adjunct to periodontal therapy. (United States)

    Gandi, Padma; Rajavasireddi, Shravanthi Rajah; Gurram, Sindhura Reddy


    A variety of treatment modalities, from removable partial dentures, fixed prosthesis to implant placement can be used for replacement of missing teeth. Anterior diastema closure is one of the most challenging tasks; it is appreciable that restorative approach is the fastest, simplest and most predictable. This case report presents a successfully accomplished closure of diastema in mandibular anterior teeth, and splinting of the adjacent teeth which were grade II mobile. This present treatment modality offers a conservative, aesthetic and non-invasive treatment which can be considered as a long-lasting treatment.

  15. Closure Plan for Active Low Level Burial Grounds

    Energy Technology Data Exchange (ETDEWEB)

    SKELLY, W.A.


    This plan has been prepared in response to direction from the U.S. Department of Energy. The purpose of the plan is to define approaches that will be implemented to ensure protection of the public and the environment when active Low-Level Burial Grounds (LLBGs) at the Hanford Site are closed. Performance assessments for active burial grounds in the 200 East and West 200 Areas provide current estimates of potential environmental contamination and doses to the ''maximum exposed individual'' from burial ground operation and closure and compare dose estimates to performance objective dose limits for the facilities. This is an Operational Closure Plan. The intent of the guidance in DOE Order 435.1 is that this plan will be a living document, like the facility performance assessments, and will be revised periodically through the operational life of the LLBGs to reflect updated information on waste inventory. management practices, facility transition planning, schedule dates, assessments of post-closure performance, and environmental consequences. Out year dates identified in this plan are tentative. A Final Closure Plan will be prepared in the future when the timing and extent of closure-related activities for LLBGs can be established with greater certainty. After current operations at the LLBGs are concluded, this plan proposes transitioning of these facilities to the Environmental Restoration Program. This action will enable the Environmental Restoration Program to design and implement consistent and coordinated final remedial actions for active and inactive LLBGs. Active and inactive burial grounds in the 200 West and 200 East Areas are commingled. This plan describes approaches that will be implemented during Interim Closure, Final Closure, and Institutional Control Periods to prepare LLBGs for surface barriers, and the construction of barriers, as well as the scope of inspection, monitoring and maintenance practices that will be performed during

  16. Bilateral Anterior Rectus Sheath Turnover Flap for Abdominal Closure

    Directory of Open Access Journals (Sweden)

    Bulent Kaya


    Full Text Available The management of abdominal wall hernias with tissue loss is a difficult subject.Several surgical techniques have been used in the treatment. Sometimes closure of the abdomen with primary sutures may be impossible. Dual meshes, component separation technique, usculofascial flaps can be used for closure of the abdomen.In this case report a patient with complex abdominal wall hernia was presented.The abdomen was successfully closed with anterior rectus sheath turnover flap.We discussed this surgical technique with literature review.

  17. A Lagrangian photoresponse model coupled with 2nd-order turbulence closure (United States)

    Nagai, T.; Yamazaki, H.; Kamykowski, D.


    Vertical mixing can transport nutrients from deep layer to euphotic zone. Therefore, it plays a very important role for biological productivity. Also, it can transport phytoplankton vertically and varies light exposure history of individual phytoplankton. When phytoplankton_fs response to the ambient light intensity is slow compare to the time scale of vertical mixing, production averaged in space can be varied caused by vertical mixing. In the past, such effects of vertical mixing on the photoresponse of phytoplankton have been considered with constant eddy diffusivity. However, vertical mixing is not independent of time, and variable vertical mixing in time should be examined for the Lagrangian photoresponse. In present study, a 2nd-order turbulence closure approach was coupled with a Lagrangian phytoplankton model, in order to examine the effect of time-dependent vertical eddy diffusion on the photoresponse of phytoplankton in a wind-driven upper mixing layer. In general, stronger wind mixing in a lower-transparency water column contributes to greater phytoplankton production. According to our study, vertical mixing is insignificant for photoinhibition in relatively clear open ocean water, while it can be more important in relatively turbid coastal water. A simple Ekman layer model provided surprisingly similar production to that observed with the 2nd-order closure scheme when the starting distribution of the phytoplankton cells was normalized. Two factors involved in the process are the change in the background stratification and the time dependence of the diffusivity coefficient. The influences of these 2 factors cancel each other to reduce the apparent difference between the total production estimated by the Ekman model compared to that estimated by the 2nd-order closure scheme.

  18. Large-scale structure

    CERN Document Server

    White, S D M


    Abstract. Recent observational surveys have made substantial progress in quantifying the structure of the Universe on large scales. Galaxy density and galaxy velocity fields show deviations from the predictions of a homogeneous and isotropic world model on scales approaching one percent of the current hori— zon scale. A comparison of the amplitudes in density and in velocity provides the first direct dynamical evidence in favour of a high mean density similar to that required for closure. The fluctuations observed on these scales have the amplitude predicted by the standard Cold Dark Matter (CDM) model when this model is normalised to agree with the microwave background fluc- tuations measured on much larger scales by the COBE satellite. However, a CDM model with this amplitude appears inconsistent with observational data on smaller scales. In addition it predicts a scale dependence of fluctua— tion amplitude which disagrees with that observed for galaxies in the APM survey of two million faint galaxi...

  19. A Three-Dimensional Scale-adaptive Turbulent Kinetic Energy Model in ARW-WRF Model (United States)

    Zhang, Xu; Bao, Jian-Wen; Chen, Baode


    A new three-dimensional (3D) turbulent kinetic energy (TKE) subgrid mixing model is developed to address the problem of simulating the convective boundary layer (CBL) across the terra incognita in the Advanced Research version of the Weather Research and Forecasting Model (ARW-WRF). The new model combines the horizontal and vertical subgrid turbulent mixing into a single energetically consistent framework, in contrast to the convectional one-dimensional (1D) planetary boundary layer (PBL) schemes. The transition between large-eddy simulation (LES) and mesoscale limit is accomplished in the new scale-adaptive model. A series of dry CBL and real-time simulations using the WRF model are carried out, in which the newly-developed, scale-adaptive, more general and energetically consistent TKE-based model is compared with the conventional 1D TKE-based PBL schemes for parameterizing vertical subgrid turbulent mixing against the WRF LES dataset and observations. The characteristics of the WRF-simulated results using the new and conventional schemes are compared. The importance of including the nonlocal component in the vertical buoyancy specification in the newly-developed general TKE-based scheme is illustrated. The improvements of the new scheme over convectional PBL schemes across the terra incognita can be seen in the partitioning of vertical flux profiles. Through comparing the results from the simulations against the WRF LES dataset and observations, we will show the feasibility of using the new scheme in the WRF model in the lieu of the conventional PBL parameterization schemes.

  20. Pediatric high speed digital imaging of vocal fold vibration: A normative pilot study of glottal closure and phase closure characteristics (United States)

    Patel, Rita R.; Dixon, Angela; Richmond, AnnaMary; Donohue, Kevin D.


    Objective The aim of the study is to characterize normal vibratory patterns of both glottal closure and phase closure in the pediatric population with the use of high speed digital imaging. Methods For this prospective study a total of 56 pre-pubertal children, 5–11 years (boys = 28, girls = 28) and 56 adults, 21–45 years (males = 28, females = 28) without known voice problems were examined with the use of a new technology of high speed digital imaging. Recordings were captured at 4000 frames per second for duration of 4.094 seconds at participants’ typical phonation. With semi-automated software, montage analysis of glottal cycles was performed. Three trained experienced raters, rated features of glottal configuration and phase closure from glottal cycle montages. Results Posterior glottal gap was the predominant glottal closure configuration in children (girls = 85%, boys = 68%) with normal voice. Other glottal configurations observed were: anterior gap (girls = 3.6%, boys = 0%), complete closure (girls = 7%, boys = 10%), hour glass (girls = 0%, boys = 11%). Adults with normal voice also demonstrated predominantly higher percentage of posterior glottal gap configuration (females = 75% male = 54%) compared to the configurations of anterior gap (females = 0% male = 7%), complete closure (females = 2% male = 39%), hour glass (females = 3.6% male = 3.6%). A predominantly open phase (51–70% of the glottal cycle) was observed in 86% girls and 71% boys. Compared to children, adult females showed a predominantly balance phased closure 46%, followed by open phase (39%) and predominantly closed phase (14%). Adult males showed a predominantly closed phase (43%), followed by predominantly open phase (39%), followed by a balanced phase (18%). Conclusions This is a first study investigating characteristics of normal vibratory motion in children with high speed digital imaging. Glottal configuration and phase closure for children with normal voices are distinctly

  1. 78 FR 75913 - Final Tank Closure and Waste Management Environmental Impact Statement for the Hanford Site... (United States)


    ... Tank Closure and Waste Management Environmental Impact Statement for the Hanford Site, Richland... Final Tank Closure and Waste Management Environmental Impact Statement for the Hanford Site, Richland... security and management). Activities under the Environmental Assessment, Sodium Residuals Reaction/Removal...

  2. Presenting features of primary angle-closure glaucoma in patients of ...

    African Journals Online (AJOL)

    closure glaucoma depends on their ethnic background. In order to examine the presenting features and effects of primary angle-closure glaucoma in people of mixed ethnicity, we reviewed all 'coloured' patients who presented to Groote Schuur ...


    CERN Multimedia

    ST/CV-ST/TFM Groups


    To save on energy costs, the heating will once again be operating at a reduced level during the end-of-year closure of the Laboratory. We would ask all those in charge of premises where normal temperature have to be maintained to let us know by 21 December 2000 at the latest (tel. 74195 or 72201).

  4. 30 CFR 57.4603 - Closure of valves. (United States)


    ... Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Fire Prevention and Control Welding/cutting/compressed Gases § 57.4603 Closure of valves. To prevent accidental release of...

  5. 30 CFR 56.4603 - Closure of valves. (United States)


    ... Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Fire Prevention and Control Welding/cutting/compressed Gases § 56.4603 Closure of valves. To prevent accidental release of...

  6. From Castalia to Wikipedia: Openness and Closure in Knowledge Communities (United States)

    Roberts, Peter; Peters, Michael A.


    This article explores different forms of openness and closure in two knowledge communities: the fictional world of Castalia in Hermann Hesse's great work "The Glass Bead Game", and the twenty-first-century cyberspatial universe of Wikipedia. These two worlds differ in some important respects, but they also share a number of educationally…

  7. Factors influencing ring closure through olefin metathesis-A ...

    Indian Academy of Sciences (India)

    Success of ring closure reactions of substrates having two terminal alkenes through olefin metathesis depends on a number of factors such as catalysts, nature and size of the rings to be formed and the substituents/functional groups present on the alkenes as well as at the allylic position. This article presents an overview of ...

  8. Risk of angle-closure glaucoma with bupropion and topiramate. (United States)

    Symes, Richard J; Etminan, Mahyar; Mikelberg, Frederick S


    Epidemiologic studies have shown that antidepressants may increase the risk of angle-closure glaucoma. We examined the risk of angle-closure glaucoma with bupropion hydrochloride, a unique, popular antidepressant also marketed as a smoking cessation aid. A nested case-control study was conducted using a large health claims database in the United States from January 1, 2006, to March 31, 2014. The database contained deidentified information pertaining to a cohort of 6 110 723 patients. Cases were defined according to the first coding for angle-closure glaucoma. For each case, 10 control participants were selected and matched to the cases using density-based sampling. Adjusted rate ratios were computed for bupropion, topiramate (positive control group drug), and esomeprazole (negative control group drug). The adjusted rate ratio was 1.09 (95% CI, 0.75-1.59) for bupropion and 2.59 (95% CI, 1.56-4.30) for topiramate. In a prespecified analysis of patients younger than 50 years, the adjusted rate ratio was 1.98 (95% CI, 1.02-3.84) for bupropion and 5.30 (95% CI, 2.54-11.04) for topiramate. Both bupropion and topiramate are widely prescribed drugs. The risk of angle-closure glaucoma in patients younger than 50 years was twice as high in patients taking bupropion and more than 5 times higher in patients taking topiramate.

  9. The Development of Closure Devices for Flexible Containers (United States)


    any other )erson or corporation, or conveying any rights or permission to manifacture , use, or sell any patented invention that mey in any way he...the additional benefit of effective handling and trdnsporting techniques. However, the methods of closing and opening (closure devices) have been

  10. Threats and opportunities for post-closure development in dolomitic ...

    African Journals Online (AJOL)

    Threats and opportunities for post-closure development in dolomitic gold-mining areas of the West Rand and Far West Rand (South Africa) – a hydraulic view Part 2: ... Keywords: post-mining development, karst, groundwater storage and harvesting, subterranean hydro-energy generation, tourism, wasteland transformation, ...

  11. Multivariate moment closure techniques for stochastic kinetic models

    Energy Technology Data Exchange (ETDEWEB)

    Lakatos, Eszter, E-mail:; Ale, Angelique; Kirk, Paul D. W.; Stumpf, Michael P. H., E-mail: [Department of Life Sciences, Centre for Integrative Systems Biology and Bioinformatics, Imperial College London, London SW7 2AZ (United Kingdom)


    Stochastic effects dominate many chemical and biochemical processes. Their analysis, however, can be computationally prohibitively expensive and a range of approximation schemes have been proposed to lighten the computational burden. These, notably the increasingly popular linear noise approximation and the more general moment expansion methods, perform well for many dynamical regimes, especially linear systems. At higher levels of nonlinearity, it comes to an interplay between the nonlinearities and the stochastic dynamics, which is much harder to capture correctly by such approximations to the true stochastic processes. Moment-closure approaches promise to address this problem by capturing higher-order terms of the temporally evolving probability distribution. Here, we develop a set of multivariate moment-closures that allows us to describe the stochastic dynamics of nonlinear systems. Multivariate closure captures the way that correlations between different molecular species, induced by the reaction dynamics, interact with stochastic effects. We use multivariate Gaussian, gamma, and lognormal closure and illustrate their use in the context of two models that have proved challenging to the previous attempts at approximating stochastic dynamics: oscillations in p53 and Hes1. In addition, we consider a larger system, Erk-mediated mitogen-activated protein kinases signalling, where conventional stochastic simulation approaches incur unacceptably high computational costs.

  12. The role of ethnicity in primary angle-closure glaucoma

    African Journals Online (AJOL)


    Sep 9, 1994 ... 2. Bengtsson B. The prevalence of glaucoma. Br J Ophthalmo/1981i-65: 46-49. 3. Congdon N, Wang F, Tielsch JM. Issues in the epidemiology and population- based screening of primary angle-closure glaucoma. Surv Ophtha/mol 1992; 36: 411-423. 4. Loh PCK. The problem of glaucoma in Singapore.

  13. Cystic duct closure by sealing with bipolar electrocoagulation

    DEFF Research Database (Denmark)

    Schulze, S; Damgaard, B; Jørgensen, Lars Nannestad


    BACKGROUND: Cystic duct leakage after cholecystectomy is not uncommon and is a potentially serious complication. The aim of this study was to assess a bipolar sealing system (LigaSure) for closure of the cystic duct. METHODS: The records from consecutive laparoscopic cholecystectomies performed...

  14. Decentralisation as Ethnic Closure, with Special Reference to a ...

    African Journals Online (AJOL)



    Sep 16, 2006 ... Contemporary Nuer accrue ownership rights over the land to the state, while. Anywaa territoriality is destined to disconnect with the state's own claim over the land. This is as much Nuer's exit strategy from Anywaa's closure as it is playing real politik.10 For, the Ethiopian state, across regimes, has claimed.

  15. 31. Left ventricular dysfunction after patent ductus arteriosus (PDA closure

    Directory of Open Access Journals (Sweden)

    Rihab Agouba


    Conclusions: Depressed LV-SFx may occur after PDA closure with higher incidence after catheter PDA device occlusion. All of preterm babies had surgical PDA occlusion and none of them presented with depressed LV-SFx in the post-operative follow-up. Further prospective studies are needed to investigate these observations.

  16. Device Closure of Small Ventricular Septal Defects: When and Why?

    Directory of Open Access Journals (Sweden)

    IB Vijayalakshmi


    Full Text Available Ventricular septal defect (VSD accounts for approximately 20-30 % of all forms of congenital heart disease (CHD. They were traditionally closed surgically in the past. The surgery though safe carries the risk of morbidity, complete heart block, wound infection and thoracotomy scar on the chest. On weighing the risk and benefit, the small VSDs were not submitted to surgery in the past. So for many years it has been taught that the small VSDs are to be left alone and surgery is not recommended. Many clinicians believed in spontaneous closure of VSDs. Hence they advised the parents to wait for spontaneous closure till the child is 9 years old. But what if the VSD does not close by 10 years is the question. Are they normal as grown up congenital heart (GUCH. The Jane Somerville GUCH unit showed that spontaneous closure occurred only in 10% between the age of 17 and 45 (mean - 27 years in small VSDs in adults. What is worth noting is about 25% had serious complications: infective endocarditis (11%, progressive aortic regurgitation (5%, age-related symptomatic arrhythmias (8.5% like atrial fibrillation. This means that asymptomatic small VSDs in childhood is not necessarily benign during adult life. This raises the question, when we have a safe non-surgical device closure available to close the small VSDs, should we put the future lives of the young in danger by not giving the benefit of technology to them?

  17. Atraumatic intracutaneous skin closure with self-made fishing line ...

    African Journals Online (AJOL)

    Objective: The aim of this study was to prove, whether the intracutaneous skin closure with self made fishing line suture is equivalent to commercial sutures. Design: It was a randomised blinded animal study. Setting: The study was performed in December 2002 at the Muhimbili University College of Health Sciences in ...

  18. Skin closure after groin hernia repair in children: a comparative ...

    African Journals Online (AJOL)

    Skin closure after groin hernia repair in children: a comparative study of three suture materials and two suture techniques La fermeture de la peau après la réparation de l'hernie de l'aine chez les enfants: une étude comparative de trois matériaux de suture et de deux techniques de suture.

  19. Techniques and materials for skin closure in caesarean section

    DEFF Research Database (Denmark)

    Mackeen, A Dhanya; Berghella, Vincenzo; Larsen, Mie-Louise


    Caesarean section is a common operation with no agreed upon standard regarding certain operative techniques or materials to use. With regard to skin closure, the skin incision can be re-approximated by a subcuticular suture immediately below the skin layer, by an interrupted suture, or by staples...

  20. Skin closure after groin hernia repair in children: a comparative ...

    African Journals Online (AJOL)

    Patients and Methods: Three suture materials (chromic catgut 3/0, silk 3/0 and nylon 3/0) and two skin closure techniques (transcutaneous interrupted mattress and subcuticular continuous running sutures) were compared in a randomized partially blinded fashion using a groin skin crease incision. The resulting scars were ...

  1. Simultaneous oroantral communication closure, sinus‑lifting, and ...

    African Journals Online (AJOL)

    The aim of this paper is to introduce an alternative technique for the treatment of oroantral communication (OAC). Closure of OAC, reconstruction of the posterior maxilla by sinus‑lifting procedure with a particulate xenograft, and implant insertion were performed in the same operation. A lateral antral approach was used in ...

  2. 10 CFR 60.51 - License amendment for permanent closure. (United States)


    ....51 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) DISPOSAL OF HIGH-LEVEL RADIOACTIVE WASTES IN... license was issued. (b) If necessary, so as to take into account the environmental impact of any... information regarding the environmental impacts of such closure, DOE shall also supplement its environmental...

  3. Feasibility of lane closures using probe data : technical brief. (United States)


    This study developed an on-line system analysis tool called the Work Zone Interactive : Management Application - Planning (WIMAP-P), an easy-to-use and easy-to-learn tool for : predicting the traffic impact caused by work zone lane closures on freewa...

  4. 40 CFR 265.143 - Financial assurance for closure. (United States)


    ... expenditures by submitting itemized bills to the Regional Administrator. The owner or operator may request... bills for partial or final closure activities, the Regional Administrator will instruct the trustee to... bond must guarantee that the owner or operator will: (i) Fund the standby trust fund in an amount equal...

  5. Intratracheal Seal Disc: A Novel Tracheostoma Closure Device. (United States)

    Christiansen, Karen J; Moeslund, Niels; Lauridsen, Henrik; Devantier, Louise; Rohde, Marianne C; Kjærgaard, Benedict; Pedersen, Michael


    Tracheostomy decannulation is accompanied by several clinical concerns due to air leakage. In this study, we introduced a novel tracheostoma closure device that facilitates the use of noninvasive ventilation, improvement of pulmonary function, and vocalization in the newly decannulated patient. The biosafety and feasibility of the device were evaluated in an animal model. Five Danish Landrace pigs were subjected to tracheostomy followed by decannulation and insertion of the tracheostoma closure device. Correct placement of the device was ensured by flexible tracheoscopy. The device consisted of an intratracheal silicone seal disc fixated by a cord through the stoma to an external part. At day 14, computed tomography (CT) was performed before the device was extracted. With the pulling of a cord, the disc unraveled into a thin thread and was extracted through the stoma. At day 21, CT was repeated before euthanasia. The trachea and epidermis were excised en bloc for histopathological evaluation. Insertion and correct placement of the disc was unproblematic in all animals. CT at day 14 confirmed a clear airway, appropriate placement of the disc, and full closure of the tracheostoma. Extraction was successful in one animal but complicated in the remaining animals. There was histological evidence of healing after the foreign body placement. The study demonstrated that the tracheostoma closure device is feasible and biosafe in a porcine animal model, but the design and quality of the materials need to be improved before clinical trials. Copyright © 2017 by Daedalus Enterprises.

  6. Cleft lip repair with subcuticular closure at National Orthopaedic ...

    African Journals Online (AJOL)

    Nigerian Journal of Plastic Surgery ... This five year study was undertaken to verify if subcuticular closure in unilateral cleft lip surgery reduced the burden of care. ... Result: Patients with skin suture had 124 surgical sessions and a mean of 7.11 days after surgery before discharge; and those with subcuticular sutures spent a ...


    CERN Multimedia

    ST/CV - ST/TFM Groupes


    To save on energy costs, the heating will once again be operating at a reduced level during the end-of-year closure of the Laboratory. We would ask all those in charge of premises where normal temperature have to be maintained to let us know by 20 December 2001 at the latest (tel.74195 or 72201).

  8. Reduced heating level during the end-of-year closure

    CERN Multimedia


    To save on energy costs, the heating will once again be operating at a reduced level during the end-of-year closure of the Laboratory. We would ask all those in charge of premises where normal temperature have to be maintained to let us know by 18 December 2003 at the latest (tel. 74195 or 72201). ST/CV - ST/FM Groups


    CERN Multimedia

    ST/CV - ST/FM Groups


    To save on energy costs, the heating will once again be operating at a reduced level during the end-of-year closure of the Laboratory. We would ask all those in charge of premises where normal temperature have to be maintained to let us know by 19 December 2002 at the latest (tel. 74195 or 72201). ST/CV - ST/FM Groups

  10. Neutron and proton shell closure in the superheavy region via ...

    Indian Academy of Sciences (India)

    The plots connecting computed values and half-lives against neutron number of daughter nuclei were studied for different clusters and it is found that the next neutron shell closures occur at = 162, 172 and 184. Isotopic and isobaric mass parabolas are studied for various cluster emissions and minima of parabola ...

  11. Simultaneous Single Tooth Intrusion and Diastema Closure: A Simplified Approach. (United States)

    Jain, Isha; Hattarki, Rohan S


    Re-treatment of relapse with a full bonded appliance following an extensive course of fixed mechanotherapy is psychologically unacceptable and time-consuming for the patient. This article presents a simple removable appliance, which intrudes an extruded maxillary incisor with simultaneous closure of a diastema in an effective and fast way, reducing the need for re-treatment with fixed mechanotherapy.

  12. Preparing a base realignment and closure cleanup plan

    Energy Technology Data Exchange (ETDEWEB)

    Diecidue, A.M.; Bandrowsky, M.; Wooldridge, P. [PRC Environmental Management, Inc., McLean, VA (United States)


    Every Department of Defense (DoD) installation subject to closure or realignment is evaluating and implementing strategies for environmental response actions to facilitate the transfer of real property at the installation. The closure and realignment process is conducted pursuant to the Base Closure and Realignment Act of 1988 (Public Law 100-526, 102 Stat. 2623) (BRAC 88) or the Defense Base Closure and Realignment Act of 1990 (Public Law 101-510, 104 Stat. 1808) (BRAC 91, 93, and 95). On July 2, 1993, the President announced a five-part program to speed the economic recovery of communities where military bases are slated to close. DoD subsequently issued a policy memorandum on September 9, 1993 that provides guidance on implementing ``fast-track`` cleanup initiatives at those bases. The guidance introduces the use of BRAC cleanup teams (BCT) and the development of BRAC cleanup plans (BCP) as part of fast-track cleanup. The BCT is responsible for developing the BCP. The BCP serves as the road map for expeditious cleanup. This paper will focus on two areas: forming and working with the BCT and preparing the BCP. The paper will discuss the make-up of the BCT and how to build trust and achieve early consensus on the many issues to be addressed by the BCT. The paper also will discuss tips for forming the BCT and preparing the BCP based on the authors` experiences.

  13. Transcatheter device closure of postmyocardial infarction ventricular septal defect

    Directory of Open Access Journals (Sweden)

    You-Lin Nie


    Conclusion: Our findings indicate that transcatheter device closure of PMIVSD is technically feasible, safe, and effective to reduce the shunt. The crucial prognostic factors were ascertained to be age ≥ 80 years, systolic blood pressure ≤ 90 mmHg, and procedure time ≥180 minutes.

  14. Simultaneous oroantral communication closure, sinus‑lifting, and ...

    African Journals Online (AJOL)


    Oct 10, 2015 ... using biodegradable polyurethane foam: A feasibility study. J Oral Maxillofac. Surg 2010;68:281-6. 6. Ahmed MS, Askar NA. Combined bony closure of oroantral fistula and sinus lift with mandibular bone grafts for subsequent dental implant placement. Oral. Surg Oral Med Oral Pathol Oral Radiol Endod ...

  15. Multivariate moment closure techniques for stochastic kinetic models (United States)

    Lakatos, Eszter; Ale, Angelique; Kirk, Paul D. W.; Stumpf, Michael P. H.


    Stochastic effects dominate many chemical and biochemical processes. Their analysis, however, can be computationally prohibitively expensive and a range of approximation schemes have been proposed to lighten the computational burden. These, notably the increasingly popular linear noise approximation and the more general moment expansion methods, perform well for many dynamical regimes, especially linear systems. At higher levels of nonlinearity, it comes to an interplay between the nonlinearities and the stochastic dynamics, which is much harder to capture correctly by such approximations to the true stochastic processes. Moment-closure approaches promise to address this problem by capturing higher-order terms of the temporally evolving probability distribution. Here, we develop a set of multivariate moment-closures that allows us to describe the stochastic dynamics of nonlinear systems. Multivariate closure captures the way that correlations between different molecular species, induced by the reaction dynamics, interact with stochastic effects. We use multivariate Gaussian, gamma, and lognormal closure and illustrate their use in the context of two models that have proved challenging to the previous attempts at approximating stochastic dynamics: oscillations in p53 and Hes1. In addition, we consider a larger system, Erk-mediated mitogen-activated protein kinases signalling, where conventional stochastic simulation approaches incur unacceptably high computational costs.

  16. Role of Trichloroacetic Acid and Gelfoam in Closure of Tympanic ...

    African Journals Online (AJOL)


    Feb 7, 2018 ... Role of trichloroacetic acid and gelfoam in closure of tympanic membrane perforations. Niger J Clin Pract 2017;20:1233-6. This is an open access article distributed under the terms of the Creative Commons. Attribution-Non Commercial-Share Alike 3.0 License, which allows others to remix, tweak, and ...

  17. Closure of the vertebral canal in human embryos and fetuses

    NARCIS (Netherlands)

    Mekonen, Hayelom K.; Hikspoors, Jill P. J. M.; Mommen, Greet; Kruepunga, Nutmethee; Köhler, S. Eleonore; Lamers, Wouter H.


    The vertebral column is the paradigm of the metameric architecture of the vertebrate body. Because the number of somites is a convenient parameter to stage early human embryos, we explored whether the closure of the vertebral canal could be used similarly for staging embryos between 7 and 10weeks of

  18. Closure of open wellbores in creeping salt sheets

    NARCIS (Netherlands)

    Weijermars, R.; Jackson, M.P.A.; Van Harmelen, A.


    Safe exploration and production of pre-salt (or subsalt) hydrocarbons require that drilling operations be optimized. We introduce analytical models of wellbore closure, accounting for variations in both the wellbore net pressure and far-field flow rate of an autochthonous or allochthonous salt sheet

  19. Uterine incision closure at caesarean section: A randomised ...

    African Journals Online (AJOL)

    ... less blood loss and similar morbidity profile exteriorization of uterus during caesarean section seems to be preferred except where it is not possible because of adhesions and surgeons inexperience. Key words: Caesarean section, Uterine closure, Exteriorisation, Maternal morbidity, Neonatal outcome, Intraperitoneal.

  20. Neutron and proton shell closure in the superheavy region via ...

    Indian Academy of Sciences (India)

    emission from nuclei in the superheavy region with an aim to find the next neutron and proton shell closure in ... et al [5] studied cluster emission from the superheavy nucleus 277Ds and from its alpha decay products ... The isotope of 292116 was identified in the reaction of curium with calcium (248Cm. + 48Ca → 292116 + ...

  1. Threats and opportunities for post-closure development in dolomitic ...

    African Journals Online (AJOL)

    Threats and opportunities for post-closure development in dolomitic gold mining areas of the West Rand and Far West Rand (South Africa) – a hydraulic view Part ... Both areas are linked by the Wonderfonteinspruit, a stream drawing much national and international media attention for its high levels of radioactive pollution.

  2. Predictors of Premature Match Closure in Youth Mentoring Relationships. (United States)

    Kupersmidt, Janis B; Stump, Kathryn N; Stelter, Rebecca L; Rhodes, Jean E


    Although mentoring is a popular and effective means of intervention with youth, the positive effects of mentoring can be diminished by premature match closure of relationships. Program, mentor, and mentee characteristics were examined as predictors of premature match closure. Secondary data analyses were conducted on a large national database of mentoring programs consisting of match and youth risk information from 170 mentoring programs and 6468 matches from across the U.S. Premature closure was associated with mentee age at match inception and 19 individual mentee characteristics. The set of mentee characteristics were examined as part of a cumulative risk index encompassing seven conceptually combined categories including family background characteristics, school functioning problems, engagement in risky health behaviors, self-regulation difficulties, engagement in illegal or criminal activities, and internalizing and externalizing behavior problems. Both the age of mentees when matched and the cumulative risk index score significantly predicted premature closure. Results are discussed in terms of directions for future research and suggestions for enhancing mentoring program practices. © Society for Community Research and Action 2017.

  3. Optimal Technique for Abdominal Fascial Closure in Liver Transplant Patients

    Directory of Open Access Journals (Sweden)

    Unal Aydin


    Conclusion: Our results indicate that the novel technique used in this study contributed to overcoming early and late postoperative complications associated with closure of the abdominal fascia in liver transplant patients. In addition, this new technique has proven to be easily applicable, faster, safer and efficient in these patients; it is also potentially useful for conventional surgery.

  4. 40 CFR 146.72 - Post-closure care. (United States)


    ... cleanups required under § 146.64; and (vi) The estimated cost of proposed post-closure care. (5) At the... over drilling activities to enable such State and local authorities to impose appropriate conditions on subsequent drilling activities that may penetrate the well's confining or injection zone. (5) Retain, for a...

  5. Is angle closure glaucoma a problem in Nigeria? | Olawoye ...

    African Journals Online (AJOL)

    Twelve eyes underwent laser iridotomy or surgical iridotomy and others had trabeculectomy or antiglaucoma medications. Mean IOP post intervention was 17.4 ± 6.9 mmHg. Conclusion: ACG is not an uncommon disease. Early and effective diagnosis is important to prevent blindness. Key words: Angle closure, glaucoma, ...

  6. An Indian perspective on primary angle closure and glaucoma

    Directory of Open Access Journals (Sweden)

    Sihota Ramanjit


    Full Text Available Aim: To provide a synopsis of primary angle closure disease in India, and Indian studies on the same. Results: Primary angle closure glaucoma forms almost half of all adult primary glaucomas seen in a hospital setting in India. Anatomically, corneal diameters and anterior chamber depths were least in acute and chronic PACG eyes as compared to subacute eyes and controls. Besides relative pupillary block, a Valsalva maneuver during activities of daily living may be responsible for intermittent angle closure and raised IOP in predisposed eyes. Iridotomy alone, controlled the intraocular pressure in 66.7% of subacute eyes and 12.9% of the acute. Medical therapy was additionally required for 35.5% of the acute eyes, 12.1% of the subacute and 30.0% of the chronic cases. There was a greater mean and peak IOP reduction, achieved with 0.005% latanoprost once daily, 8.2 ± 2.0 mm Hg, compared with 0.5% timolol twice daily, 6.1 ± 1.7 mm Hg2. A progression of PACS to PAC was seen in 22%, PAC to PAC OHT in 38.7% and PAC OHT to PACG in 30.7% over 5 years. Conclusions: Primary angle closure disease is common in India, and can be managed well with iridotomy, followed by an appropriate control of IOP.

  7. Effective closure temperature in leaky and/or saturating thermochronometers

    DEFF Research Database (Denmark)

    Guralnik, Benny; Jain, Mayank; Herman, Frédéric


    The classical equation of closure temperature (TC) in thermochronometry (Dodson, 1973), assumed (i) no storage limitation for the accumulating radiogenic product, (ii) a negligible product concentration at the initial temperature of cooling T0, and (iii) a negligible product loss at the final (pr...

  8. Modeling closure of circular wounds through coordinated collective motion. (United States)

    Li, David S; Zimmermann, Juliane; Levine, Herbert


    Wound healing enables tissues to restore their original states, and is achieved through collective cell migration into the wound space, contraction of the wound edge via an actomyosin filament 'purse-string,' as well as cell division. Recently, experimental techniques have been developed to create wounds with various regular morphologies in epithelial monolayers, and these experiments of circular closed-contour wounds support coordinated lamellipodial cell crawling as the predominant driver of gap closure. Through utilizing a particle-based mechanical tissue simulation, exhibiting long-range coordination of cell motility, we computationally model these closed-contour experiments with a high level of agreement between experimentally observed and simulated wound closure dynamics and tissue velocity profiles. We also determine the sensitivity of wound closure time in the model to changes in cell motility force and division rate. Our simulation results confirm that circular wounds can close due to collective cell migration without the necessity for a purse-string mechanism or for cell division, and show that the alignment mechanism of cellular motility force with velocity, leading to collective motion in the model, may speed up wound closure.

  9. Clinical trial comparing excision and primary closure with modified ...

    African Journals Online (AJOL)

    Walid Galal Elshazly


    Dec 3, 2011 ... Abstract The aim of this study was to compare modified Limberg flap procedure with excision and primary closure in the treatment of uncomplicated pilonidal disease. Methods: This study was conducted on 120 patients with uncomplicated sacrococcygeal pilonidal disease that were randomly allocated into ...

  10. Vacuum-assisted closure : indications and clinical experience

    NARCIS (Netherlands)

    Schasfoort, RA; Obdeijn, MC; Nicolai, JPA; van der Werf, J.F.A.; de Lange, M.

    The use of subatmospheric pressure to promote wound healing has gradually found support in the past few years. The vacuum-assisted closure system uses a pump providing a continuous negative pressure of preferably 125 mmHg, which is distributed over the wound surface by an airtight covered foam. The

  11. Complex transitive closure queries on a fragmented graph

    NARCIS (Netherlands)

    Houtsma, M.A.W.; Houtsma, Maurice A.W.; Apers, Peter M.G.; Ceri, Stefano; Abiteboul, Serge; Kanellakis, Paris C.


    In this paper we study the reformulation of transitive closure queries on a fragmented graph. We split a query into several subqueries, each requiring only a fragment of the graph. We prove this reformulation to be correct for shortest path and bill of material queries. Here we describe the

  12. Localization effects of firm startups and closures in the Netherlands

    NARCIS (Netherlands)

    Huisman, Corina; van Wissen, L

    In this article localization trends as a result of startups and closures are investigated in the Netherlands, using a distance-based approach. A major advantage of this method is that it does not suffer from aggregation bias that is inherent in area-based methods. This method controls for the

  13. Decision support system for road closures in flash flood emergencies. (United States)


    Among all the natural hazards, flash flood ranks as the No. 1 weather-related killer in U.S. More : than half of the deaths in flash flood are due to drowning victims in a traffic environment. So road : closure is critical to save lives from flash fl...

  14. Review on improved seismic imaging with closure phase

    KAUST Repository

    Schuster, Gerard T.


    The timing and amplitudes of arrivals recorded in seismic traces are influenced by velocity variations all along the associated raypaths. Consequently, velocity errors far from the target can lead to blurred imaging of the target body. To partly remedy this problem, we comprehensively reviewed inverting differential traveltimes that satisfied the closure-phase condition. The result is that the source and receiver statics are completely eliminated in the data and velocities far from the target do not need to be known. We successfully used the phase closure equation for traveltime tomography, refraction statics, migration, refraction tomography, and earthquake location, all of which demonstrated the higher resolution achievable by processing data with differential traveltimes rather than absolute traveltimes. More generally, the stationary version of the closure-phase equation is equivalent to Fermat’s principle and can be derived from the equations of seismic interferometry. In summary, the general closure-phase equation is the mathematical foundation for approximately redatuming sources and/or receivers to the target of interest without the need to accurately know the statics or the velocity model away from the target.

  15. Budget cuts force early closure of Stanford collider

    CERN Multimedia


    in Brief Stanford's B-meson work is coming to an early end.SLACIn early March, California's Stanford Linear Accelerator Center (SLAC) will shut down a collider that produces B mesons. The closure means that the lab's commitment to BaBar - an international collaboration studying the differences between matter and antimatter - will now end seven months early.

  16. Staged Closure of Giant Omphalocele using Synthetic Mesh


    Lalit Parida; Kamalesh Pal; Hussah Al Buainain; Hossam Elshafei


    Giant omphalocele is difficult to manage and is associated with a poor outcome. A male newborn presented to our hospital with a giant omphalocele. We performed a staged closure of giant omphalocele using synthetic mesh to construct a silo and then mesh abdominoplasty in the neonatal period that led to a successful outcome within a reasonable period of hospital stay.

  17. Commentary on Predictors of Failed Primary Abdominal Closure in the Trauma Patient with an Open Abdomen (United States)


    TAC techniques and 18% to 22% with fascial -based methods. Beale and colleagues found no difference between closure rates when fascial -based methods...pressureYbased methods of TAC. As TAC methods have evolved, a combination of these techniques has been termed vacuum-assisted fascial closure, and...with a vacuum-assisted fascial closure technique using the commercially available Vacuum-Assisted Closure (KCI, San Antonio, TX) device with interrupted

  18. Management of hidradenitis suppurativa wounds with an internal vacuum-assisted closure device. (United States)

    Chen, Y Erin; Gerstle, Theodore; Verma, Kapil; Treiser, Matthew D; Kimball, Alexandra B; Orgill, Dennis P


    Hidradenitis suppurativa is a chronic, debilitating disease that is difficult to treat. Once medical management fails, wide local excision offers the best chance for cure. However, the resultant wound often proves too large or contaminated for immediate closure. The authors performed a retrospective chart review of hidradenitis cases managed surgically between 2005 and 2010. Data collected included patient characteristics, management method, and outcomes. Approximately half of the patients received internal vacuum-assisted closure therapy using the vacuum-assisted closure system and delayed closure and half of the patients received immediate primary closure at the time of their excision. Delayed closure consisted of closing the majority of the wound in a linear fashion following internal vacuum-assisted closure while accepting healing by means of secondary intention for small wound areas. Patients managed with internal vacuum-assisted closure had wounds on average four times larger in area than patients managed without internal vacuum-assisted closure. In both groups, all wounds were eventually closed primarily. Healing times averaged 2.2 months with internal vacuum-assisted closure and 2.7 months without. At an average follow-up time of 2.3 months, all patients with internal vacuum-assisted closure had no recurrence of their local disease. Severe hidradenitis presents a treatment challenge, as surgical excisions are often complicated by difficult closures and unsatisfactory recurrence rates. This study demonstrates that wide local excision with reasonable outcomes can be achieved using accelerated delayed primary closure. This method uses internal vacuum-assisted closure as a bridge between excision and delayed primary closure, facilitating closure without recurrence in large, heavily contaminated wounds. Therapeutic, III.

  19. 77 FR 74119 - Snapper-Grouper Fishery of the South Atlantic; 2012 Commercial Accountability Measure and Closure... (United States)


    ... the South Atlantic; 2012 Commercial Accountability Measure and Closure for South Atlantic Snowy... (NOAA), Commerce. ACTION: Temporary rule; closure. SUMMARY: NMFS implements accountability measures (AMs...

  20. Appendectomy Skin Closure Technique, Randomized Controlled Trial: Changing Paradigms (ASC). (United States)

    Andrade, Luis Angel Medina; Muñoz, Franz Yeudiel Pérez; Báez, María Valeria Jiménez; Collazos, Stephanie Serrano; de Los Angeles Martinez Ferretiz, Maria; Ruiz, Brenda; Montes, Oscar; Woolf, Stephanie; Noriega, Jessica Gonzalez; Aparicio, Uriel Maldonado; Gonzalez, Israel Gonzalez


    Appendectomy is the most frequent and urgent gastrointestinal surgery. Overtime, the surgical techniques have been improved upon, in order to reduce complications, get better cosmetic results, and limit the discomfort associated with this procedure, by its high impact in the surgery departments. The traditional skin closure is associated with a poor cosmetic result and it requires stitches removal, alongside the pain associated with this procedure, and no benefits were demonstrated in the literature regarding separated stitches over intradermic stitch. This is a randomized controlled trial, and our objective is to compare two different skin closure techniques in open appendectomy. A prospective randomized trial method was used, with a total number of 208 patients participating in the study, after acute appendicitis diagnosis in the emergency department. They were randomized into two groups: patients who would receive skin closure with a unique absorbable intradermic stitch (Group A) and another group that would receive the traditional closure technique, consistent in non-absorbable separated stitches (Group B). General characteristics like gender, age, Body Mass Index (BMI), comorbidities, and allergies were registered. Days of Evolution (DOE) until surgery, previous use of antibiotics, complicated or uncomplicated appendicitis, surgical time, and wound complications like skin infection, dehiscence, seroma or abscess were also registered in each case. 8 patients were excluded due to negative appendicitis during surgery and lack of follow-up. Two groups, each containing 100 patients, were formed. General characteristics and parity were compared, and no statistically significant differences were observed. Difference in the surgical time (Group A: 47.35 min vs Group B: 54.13 min, p  25 kg/m2 and seroma (p = .006), BMI > 25 kg/m2 and abscess (p = .02), surgical time >50 min and seroma (p 2 DOE and abscess (p = .001), and complicated appendicitis with

  1. Physical modelling of interactions between interfaces and turbulence; Modelisation physique des interactions entre interfaces et turbulence

    Energy Technology Data Exchange (ETDEWEB)

    Toutant, A


    The complex interactions between interfaces and turbulence strongly impact the flow properties. Unfortunately, Direct Numerical Simulations (DNS) have to entail a number of degrees of freedom proportional to the third power of the Reynolds number to correctly describe the flow behaviour. This extremely hard constraint makes it impossible to use DNS for industrial applications. Our strategy consists in using and improving DNS method in order to develop the Interfaces and Sub-grid Scales concept. ISS is a two-phase equivalent to the single-phase Large Eddy Simulation (LES) concept. The challenge of ISS is to integrate the two-way coupling phenomenon into sub-grid models. Applying a space filter, we have exhibited correlations or sub-grid terms that require closures. We have shown that, in two-phase flows, the presence of a discontinuity leads to specific sub-grid terms. Comparing the maximum of the norm of the sub-grid terms with the maximum of the norm of the advection tensor, we have found that sub-grid terms related to interfacial forces and viscous effect are negligible. Consequently, in the momentum balance, only the sub-grid terms related to inertia have to be closed. Thanks to a priori tests performed on several DNS data, we demonstrate that the scale similarity hypothesis, reinterpreted near discontinuity, provides sub-grid models that take into account the two-way coupling phenomenon. These models correspond to the first step of our work. Indeed, in this step, interfaces are smooth and, interactions between interfaces and turbulence occur in a transition zone where each physical variable varies sharply but continuously. The next challenge has been to determine the jump conditions across the sharp equivalent interface corresponding to the sub-grid models of the transition zone. We have used the matched asymptotic expansion method to obtain the jump conditions. The first tests on the velocity of the sharp equivalent interface are very promising (author)

  2. On the closure of circular holes in nonlinear viscous media. (United States)

    Cornet, Jan; Dabrowski, Marcin; Schmid, Daniel


    Many rocks exhibit viscous behaviors which have to be taken into account in applications ranging from wellbores creeping during drilling to salt caves or hard rock mine tunnels shrinking with time. We address all these different cases using a unified configuration. We consider a 2D plane strain problem where a circular hole, representing the wellbore, the cave or the mine tunnel depending on the application, is embedded in an infinite incompressible non-linear viscous material. The problem is purely mechanical. Not only the rheological model used here is well suited for real formations but it can also represent many different sorts of rocks like salts, shales, quartzite and even ice. The major difference between the applications concerns the relevant time scales and they must therefore be separated according to that. For short timescale applications like wellbore creep during drilling it is first necessary to determine whether an elastic component must or must not be taken into account. This analysis is carried out using a non-linear viscoelastic Maxwell model. If it is acknowledged that a purely viscous rheology is enough, as can be the case for salts, then we can proceed with our unified configuration. We start by considering the case where the medium is isotropic and where pressure boundary conditions are prescribed both at the hole rim and at infinity. This problem is 1D due to axial symmetry. Analytical solutions to very similar problems have already been provided and we compare the solution we have derived to the existing ones. We show that our solution is consistent and that we recover similar results to the ones derived for comparable rheologies. Using MILAMIN, a fast finite element code, we investigate further two cases which lead to angular dependency and stress concentrations around the hole. In the first case we add a deviatoric stress at infinity and we study the impact of this extra stress on the solution. It is important to understand this parameter

  3. When need for closure leads to positive attitudes towards a negatively stereotyped outgroup. (United States)

    Kossowska, Małgorzata; Dragon, Piotr; Bukowski, Marcin

    The study examined the relationship between epistemic motivation, which is the need for closure (NFC), and positive attitudes towards a negatively stereotyped outgroup (i.e., Gypsies). Although extensive research has revealed that NFC is related to derogatory behavioural tendencies and negative emotions towards stereotyped groups, it is proposed that NFC may also be linked to positive attitudes towards outgroups. It is predicted, however, that this would be true only when NFC is accompanied by a low ability to achieve closure (AAC). It is argued that low AAC impairs the construction of schema and their effective application. Therefore, NFC in individuals with low AAC may lead them to correct their initial tendency to use stereotypes and, as a consequence, to evaluate a negatively stereotyped outgroup in a positive way. In this research, low AAC was assessed by a scale (Study 1) and experimentally induced (Study 2). In both studies, we measured positive attitudes towards Gypsies. The results of the studies supported our prediction that NFC is positively related to positive attitudes towards Gypsies when AAC is low.

  4. Business closure and relocation: a comparative analysis of the Loma Prieta earthquake and Hurricane Andrew. (United States)

    Wasileski, Gabriela; Rodríguez, Havidán; Diaz, Walter


    The occurrence of a number of large-scale disasters or catastrophes in recent years, including the Indian Ocean tsunami (2004), the Kashmir earthquake (2005), Hurricane Katrina (2005) and Hurricane Ike (2008), have raised our awareness regarding the devastating effects of disasters on human populations and the importance of developing mitigation and preparedness strategies to limit the consequences of such events. However, there is still a dearth of social science research focusing on the socio-economic impact of disasters on businesses in the United States. This paper contributes to this research literature by focusing on the impact of disasters on business closure and relocation through the use of multivariate logistic regression models, specifically focusing on the Loma Prieta earthquake (1989) and Hurricane Andrew (1992). Using a multivariate model, we examine how physical damage to the infrastructure, lifeline disruption and business characteristics, among others, impact business closure and relocation following major disasters. © 2011 The Author(s). Disasters © Overseas Development Institute, 2011.

  5. Triadic closure as a basic generating mechanism of communities in complex networks. (United States)

    Bianconi, Ginestra; Darst, Richard K; Iacovacci, Jacopo; Fortunato, Santo


    Most of the complex social, technological, and biological networks have a significant community structure. Therefore the community structure of complex networks has to be considered as a universal property, together with the much explored small-world and scale-free properties of these networks. Despite the large interest in characterizing the community structures of real networks, not enough attention has been devoted to the detection of universal mechanisms able to spontaneously generate networks with communities. Triadic closure is a natural mechanism to make new connections, especially in social networks. Here we show that models of network growth based on simple triadic closure naturally lead to the emergence of community structure, together with fat-tailed distributions of node degree and high clustering coefficients. Communities emerge from the initial stochastic heterogeneity in the concentration of links, followed by a cycle of growth and fragmentation. Communities are the more pronounced, the sparser the graph, and disappear for high values of link density and randomness in the attachment procedure. By introducing a fitness-based link attractivity for the nodes, we find a phase transition where communities disappear for high heterogeneity of the fitness distribution, but a different mesoscopic organization of the nodes emerges, with groups of nodes being shared between just a few superhubs, which attract most of the links of the system.

  6. A Fruit of Yucca Mountain: The Remote Waste Package Closure System

    Energy Technology Data Exchange (ETDEWEB)

    Kevin Skinner; Greg Housley; Colleen Shelton-Davis


    Was the death of the Yucca Mountain repository the fate of a technical lemon or a political lemon? Without caution, this debate could lure us away from capitalizing on the fruits of the project. In March 2009, Idaho National Laboratory (INL) successfully demonstrated the Waste Package Closure System, a full-scale prototype system for closing waste packages that were to be entombed in the now abandoned Yucca Mountain repository. This article describes the system, which INL designed and built, to weld the closure lids on the waste packages, nondestructively examine the welds using four different techniques, repair the welds if necessary, mitigate crack initiating stresses in the surfaces of the welds, evacuate and backfill the packages with an inert gas, and perform all of these tasks remotely. As a nation, we now have a proven method for securely sealing nuclear waste packages for long term storage—regardless of whether or not the future destination for these packages will be an underground repository. Additionally, many of the system’s features and concepts may benefit other remote nuclear applications.

  7. Permanent Closure of MFC Biodiesel Underground Storage Tank 99ANL00013

    Energy Technology Data Exchange (ETDEWEB)

    Kerry L. Nisson


    This closure package documents the site assessment and permanent closure of the Materials and Fuels Complex biodiesel underground storage tank 99ANL00013 in accordance with the regulatory requirements established in 40 CFR 280.71, “Technical Standards and Corrective Action Requirements for Owners and Operators of Underground Storage Tanks: Out-of-Service UST Systems and Closure.”

  8. 78 FR 59731 - License Amendment Request for Closure of Calcium Fluoride Ponds at Honeywell Metropolis Works... (United States)


    ... COMMISSION License Amendment Request for Closure of Calcium Fluoride Ponds at Honeywell Metropolis Works...: (1) License Amendment Request Report NRC License Number SUB-526, Closure of Retention Ponds B, C, D... proposed closure plan for four ponds located on the MTW plant site. Honeywell holds NRC License No. SUB-526...

  9. 40 CFR 264.145 - Financial assurance for post-closure care. (United States)


    ...-closure care may request reimbursements for post-closure care expenditures by submitting itemized bills to the Regional Administrator. Within 60 days after receiving bills for post-closure care activities, the... bond must guarantee that the owner or operator will: (i) Fund the standby trust fund in an amount equal...

  10. PFO closuRE and CryptogenIc StrokE (PRECISE) registry

    DEFF Research Database (Denmark)

    Wöhrle, Jochen; Bertrand, Bernard; Søndergaard, Lars


    The Premere™ PFO closure device has a special design for closure of patent foramen ovale (PFO) including a flexible distance and angulation between the right and left disc providing minimal septal distortion. The primary objective of the study was to determine the degree of risk for stroke or tra...... or transient ischemic attack (TIA) in patients after Premere™ PFO closure device implantation....

  11. The timing of ostomy closure in infants with necrotizing enterocolitis: a systematic review

    NARCIS (Netherlands)

    Struijs, M.C.; Sloots, C.E.J.; Hop, W.C.J.; Tibboel, D.; Wijnen, R.M.H.


    PURPOSE: The optimal timing of ostomy closure is a matter of debate. We performed a systematic review of outcomes of early ostomy closure (EC, within 8 weeks) and late ostomy closure (LC, after 8 weeks) in infants with necrotizing enterocolitis. METHODS: PubMed, EMbase, Web-of-Science, and Cinahl

  12. The timing of ostomy closure in infants with necrotizing enterocolitis: A systematic review

    NARCIS (Netherlands)

    A.E.C.J.M. Struijs (Marie-Chantal); C.E.J. Sloots (Pim); W.C.J. Hop (Wim); D. Tibboel (Dick); R.M.H. Wijnen (René)


    textabstractPurpose The optimal timing of ostomy closure is a matter of debate. We performed a systematic review of outcomes of early ostomy closure (EC, within 8 weeks) and late ostomy closure (LC, after 8 weeks) in infants with necro-tizing enterocolitis. Methods PubMed, EMbase, Web-of-Science,

  13. ICPP tank farm closure study. Volume 2: Engineering design files

    Energy Technology Data Exchange (ETDEWEB)



    Volume 2 contains the following topical sections: Tank farm heel flushing/pH adjustment; Grouting experiments for immobilization of tank farm heel; Savannah River high level waste tank 20 closure; Tank farm closure information; Clean closure of tank farm; Remediation issues; Remote demolition techniques; Decision concerning EIS for debris treatment facility; CERCLA/RCRA issues; Area of contamination determination; Containment building of debris treatment facility; Double containment issues; Characterization costs; Packaging and disposal options for the waste resulting from the total removal of the tank farm; Take-off calculations for the total removal of soils and structures at the tank farm; Vessel off-gas systems; Jet-grouted polymer and subsurface walls; Exposure calculations for total removal of tank farm; Recommended instrumentation during retrieval operations; High level waste tank concrete encasement evaluation; Recommended heavy equipment and sizing equipment for total removal activities; Tank buoyancy constraints; Grout and concrete formulas for tank heel solidification; Tank heel pH requirements; Tank cooling water; Evaluation of conservatism of vehicle loading on vaults; Typical vault dimensions and approximately tank and vault void volumes; Radiological concerns for temporary vessel off-gas system; Flushing calculations for tank heels; Grout lift depth analysis; Decontamination solution for waste transfer piping; Grout lift determination for filling tank and vault voids; sprung structure vendor data; Grout flow properties through a 2--4 inch pipe; Tank farm load limitations; NRC low level waste grout; Project data sheet calculations; Dose rates for tank farm closure tasks; Exposure and shielding calculations for grout lines; TFF radionuclide release rates; Documentation of the clean closure of a system with listed waste discharge; and Documentation of the ORNL method of radionuclide concentrations in tanks.

  14. Intravenous paracetamol and patent ductus arteriosus closure in preterm infants

    Directory of Open Access Journals (Sweden)

    Rizky Adriansyah


    Full Text Available Background Indomethacin and ibuprofen are the drugs of choice for closure of patent ductus arteriosus (PDA in preterm infants. However, intravenous preparations are of limited availability in Indonesia. Circumstantial evidence has shown that intravenous paracetamol may be an alternative therapy for PDA closure in premature infants. Objective To evaluate the effect of intravenous paracetamol on PDA closure in preterm infants. Methods A before-and-after study was conducted between May and August 2014 in Cipto Mangunkusumo General Hospital, Jakarta in preterm infants with hemodynamically significant PDAs, as established by echocardiography using the following criteria: duct diameter >1.4 mm/kg, left atrium to aorta ratio >1.4, and mean velocity in the left pulmonary artery >0.42 m/s or mean diastolic velocity in the left pulmonary artery >0.2 m/s. Subjects, aged 2 and 7 days, received intravenous paracetamol (15 mg/kg every six hours for 3 days. Paired T-test was used to compare pre-intervention PDA diameter to those assessed at 24 hours after the intervention and at 14 days of life. Results Twenty-nine subjects had a mean gestational age of 30.8 weeks and mean birth weight of 1,347 grams. Nineteen (65.5% patients had closed PDAs at the day 14 evaluation, 1 experienced PDA reopening, and 9 had failed PDA closure. No liver toxicity was identified. Mean duct diameters before, 24 hours after the intervention, and at 14 days of life were 3.0, 0.9, and 0.6 mm, respectively (P<0.0001. Conclusion Intravenous paracetamol seems to be reasonably effective for PDA closure in preterm infants.

  15. Techniques for Abdominal Wall Closure after Damage Control Laparotomy: From Temporary Abdominal Closure to Early/Delayed Fascial Closure—A Review


    Qian Huang; Jieshou Li; Wan-yee Lau


    Open abdomen (OA) has been an effective treatment for abdominal catastrophes in traumatic and general surgery. However, management of patients with OA remains a formidable task for surgeons. The central goal of OA is closure of fascial defect as early as is clinically feasible without precipitating abdominal compartment syndrome. Historically, techniques such as packing, mesh, and vacuum-assisted closure have been developed to assist temporary abdominal closure, and techniques such as compone...

  16. Developing guidelines for school closure interventions to be used during a future influenza pandemic

    Directory of Open Access Journals (Sweden)

    Milne George J


    Full Text Available Abstract Background The A/H1N1 2009 influenza pandemic revealed that operational issues of school closure interventions, such as when school closure should be initiated (activation trigger, how long schools should be closed (duration and what type of school closure should be adopted, varied greatly between and within countries. Computer simulation can be used to examine school closure intervention strategies in order to inform public health authorities as they refine school closure guidelines in light of experience with the A/H1N1 2009 pandemic. Methods An individual-based simulation model was used to investigate the effectiveness of school closure interventions for influenza pandemics with R0 of 1.5, 2.0 and 2.5. The effectiveness of individual school closure and simultaneous school closure were analyzed for 2, 4 and 8 weeks closure duration, with a daily diagnosed case based intervention activation trigger scheme. The effectiveness of combining antiviral drug treatment and household prophyaxis with school closure was also investigated. Results Illness attack rate was reduced from 33% to 19% (14% reduction in overall attack rate by 8 weeks school closure activating at 30 daily diagnosed cases in the community for an influenza pandemic with R0 = 1.5; when combined with antivirals a 19% (from 33% to 14% reduction in attack rate was obtained. For R0 >= 2.0, school closure would be less effective. An 8 weeks school closure strategy gives 9% (from 50% to 41% and 4% (from 59% to 55% reduction in attack rate for R0 = 2.0 and 2.5 respectively; however, school closure plus antivirals would give a significant reduction (~15% in over all attack rate. The results also suggest that an individual school closure strategy would be more effective than simultaneous school closure. Conclusions Our results indicate that the particular school closure strategy to be adopted depends both on the disease severity, which will determine the duration of school closure

  17. Cardiac Device Implant Skin Closure with a Novel Adjustable, Coaptive Tape-Based Device. (United States)

    Lalani, Gautam G; Schricker, Amir A; Salcedo, Jonathan; Hebsur, Shrinivas; Hsu, Jonathan; Feld, Gregory; Birgersdotter-Green, Ulrika


    The purpose of this study was to compare a unique zip-type adjustable coaptive tape-based skin closure device to traditional subcuticular sutures in three domains: time, cosmesis, and wound closure-related outcomes in cardiac implantable electronic device (CIED) procedures. A total of 40 patients were enrolled in a prospective randomized controlled trial to assess time to wound closure, as well as cosmesis and wound closure-related outcomes. The adjustable coaptive tape-based skin closure device had shorter overall closure time (78 ± 6.6 seconds vs 216 ± 21.5 seconds; P < 0.001) and mean closure time per centimeter (18.0 ± 2.0 s/cm vs 50.1 ± 6.7 s/cm; P < 0.001) versus sutures, with less intersurgeon and interpatient variability with the use of adjustable coaptive device versus sutures (P < 0.001). There was no difference between groups in postoperative pain or scar cosmesis during the follow-up period. Neither group had any closure-related adverse events. The adjustable coaptive tape-based skin closure device demonstrated shorter closure times with less variability when compared to sutures. It is a safe and acceptable alternative to sutures for skin closure following CIED implantation. © 2016 Wiley Periodicals, Inc.

  18. A project-based Mine Closure Model (MCM) for sustainable asset Life Cycle Management

    Energy Technology Data Exchange (ETDEWEB)

    A. Fourie; A.C. Brent [University of Pretoria, Pretoria (South Africa). Life Cycle Engineering, Department of Engineering and Technology Management


    Responsible Life Cycle Management (LCM) of mines has received much attention in the South African legislation. However, there is currently a mis-alignment between the mining industry and the various government authorities pertaining to the issue of mine closure or end-of-life management. The main reasons for this are unclear and unformulated approaches to rehabilitation with a subsequent legacy of unsuccessful mine closures that have wrongly been issued by the government from a sustainability perspective; this has posed an excessive economical burden for the mining industry. In this paper, a Mine Closure Model (MCM) based on project management principles, including risk management and concurrent engineering, is proposed to manage the closure process and assist the governing body with the effective evaluation of closures and the issuance of certificates. Mine closure or rehabilitation objectives can be achieved whilst managing the resources (of industry) optimally and aligning the closure process to meet the end requirements of stakeholder groups.

  19. Vertical Velocities in Cumulus Convection: Implications for Climate and Prospects for Realistic Simulation at Cloud Scale (United States)

    Donner, Leo


    Cumulus mass fluxes are essential controls on the interactions between cumulus convection and large-scale flows. Cumulus parameterizations have generally been built around them, and these parameterizations are basic components of climate models. Several important questions in climate science depend also on cumulus vertical velocities. Interactions between aerosols and convection comprise a prominent example, and scale-aware cumulus parameterizations that require explicit information about cumulus areas are another. Basic progress on these problems requires realistic characterization of cumulus vertical velocities from observations and models. Recent deployments of dual-Doppler radars are providing unprecedented observations, which can be compared against cloud-resolving models (CRMs). The CRMs can subsequently be analyzed to develop and evaluate parameterizations of vertical velocities in climate models. Vertical velocities from several cloud models will be compared against observations in this presentation. CRM vertical velocities will be found to depend strongly on model resolution and treatment of sub-grid turbulence and microphysics. Although many current state-of-science CRMs do not simulate vertical velocities well, recent experiments with these models suggest that with appropriate treatments of sub-grid turbulence and microphysics robustly realistic modeling of cumulus vertical velocities is possible.

  20. Why the warming can't be natural: the nonlinear geophysics of climate closure (United States)

    Lovejoy, S.


    Claims with extraordinary consequences require extraordinary evidence. It is not sufficient to prove that the warming is "extremely likely" to be anthropogenic: to achieve "climate closure", we must also disprove the converse theory that it is a natural fluctuation. This disproof requires an understanding of the strongly nonlinear atmospheric variability: since the 1980's this understanding is one of the important contributions of nonlinear geophysics to the atmospheric sciences. Atmospheric variability spans twenty orders of magnitude in time and ten in space, but it can be tamed with the help of emergent high-level turbulent laws and their anisotropic and multifractal generalizations. We take a voyage through scales and with the help of some new fluctuation analysis tools, we review the arguments and evidence for wide scale range space-time scaling: high level turbulent laws. We examine the consequences for the extreme fluctuations ("grey swan", "black swan" events) and we apply this to estimating the probabilities and return times of extreme centennial, global scale temperature fluctuations. Even with conservative assumptions, the natural warming hypothesis can be rejected with >99% confidence.