CULA: hybrid GPU accelerated linear algebra routines
NASA Astrophysics Data System (ADS)
Humphrey, John R.; Price, Daniel K.; Spagnoli, Kyle E.; Paolini, Aaron L.; Kelmelis, Eric J.
2010-04-01
The modern graphics processing unit (GPU) found in many standard personal computers is a highly parallel math processor capable of nearly 1 TFLOPS peak throughput at a cost similar to a high-end CPU and an excellent FLOPS/watt ratio. High-level linear algebra operations are computationally intense, often requiring O(N3) operations and would seem a natural fit for the processing power of the GPU. Our work is on CULA, a GPU accelerated implementation of linear algebra routines. We present results from factorizations such as LU decomposition, singular value decomposition and QR decomposition along with applications like system solution and least squares. The GPU execution model featured by NVIDIA GPUs based on CUDA demands very strong parallelism, requiring between hundreds and thousands of simultaneous operations to achieve high performance. Some constructs from linear algebra map extremely well to the GPU and others map poorly. CPUs, on the other hand, do well at smaller order parallelism and perform acceptably during low-parallelism code segments. Our work addresses this via hybrid a processing model, in which the CPU and GPU work simultaneously to produce results. In many cases, this is accomplished by allowing each platform to do the work it performs most naturally.
Optimization techniques for OpenCL-based linear algebra routines
NASA Astrophysics Data System (ADS)
Kozacik, Stephen; Fox, Paul; Humphrey, John; Kuller, Aryeh; Kelmelis, Eric; Prather, Dennis W.
2014-06-01
The OpenCL standard for general-purpose parallel programming allows a developer to target highly parallel computations towards graphics processing units (GPUs), CPUs, co-processing devices, and field programmable gate arrays (FPGAs). The computationally intense domains of linear algebra and image processing have shown significant speedups when implemented in the OpenCL environment. A major benefit of OpenCL is that a routine written for one device can be run across many different devices and architectures; however, a kernel optimized for one device may not exhibit high performance when executed on a different device. For this reason kernels must typically be hand-optimized for every target device family. Due to the large number of parameters that can affect performance, hand tuning for every possible device is impractical and often produces suboptimal results. For this work, we focused on optimizing the general matrix multiplication routine. General matrix multiplication is used as a building block for many linear algebra routines and often comprises a large portion of the run-time. Prior work has shown this routine to be a good candidate for high-performance implementation in OpenCL. We selected several candidate algorithms from the literature that are suitable for parameterization. We then developed parameterized kernels implementing these algorithms using only portable OpenCL features. Our implementation queries device information supplied by the OpenCL runtime and utilizes this as well as user input to generate a search space that satisfies device and algorithmic constraints. Preliminary results from our work confirm that optimizations are not portable from one device to the next, and show the benefits of automatic tuning. Using a standard set of tuning parameters seen in the literature for the NVIDIA Fermi architecture achieves a performance of 1.6 TFLOPS on an AMD 7970 device, while automatically tuning achieves a peak of 2.7 TFLOPS
Efficient linear algebra routines for symmetric matrices stored in packed form.
Ahlrichs, Reinhart; Tsereteli, Kakha
2002-01-30
Quantum chemistry methods require various linear algebra routines for symmetric matrices, for example, diagonalization or Cholesky decomposition for positive matrices. We present a small set of these basic routines that are efficient and minimize memory requirements.
NASA Technical Reports Server (NTRS)
Hill, D. C.; Morris, S. J., Jr.
1979-01-01
A report on the computer routine INTERP3 is presented. The routine is designed to linearly interpolate a variable which is a function of three independent variables. The variables within the parameter arrays do not have to be distinct, or equally spaced, and the array variables can be in increasing or decreasing order.
Linear control of oscillator and amplifier flows*
NASA Astrophysics Data System (ADS)
Schmid, Peter J.; Sipp, Denis
2016-08-01
Linear control applied to fluid systems near an equilibrium point has important applications for many flows of industrial or fundamental interest. In this article we give an exposition of tools and approaches for the design of control strategies for globally stable or unstable flows. For unstable oscillator flows a feedback configuration and a model-based approach is proposed, while for stable noise-amplifier flows a feedforward setup and an approach based on system identification is advocated. Model reduction and robustness issues are addressed for the oscillator case; statistical learning techniques are emphasized for the amplifier case. Effective suppression of global and convective instabilities could be demonstrated for either case, even though the system-identification approach results in a superior robustness to off-design conditions.
The Piecewise Linear Reactive Flow Rate Model
Vitello, P; Souers, P C
2005-07-22
Conclusions are: (1) Early calibrations of the Piece Wise Linear reactive flow model have shown that it allows for very accurate agreement with data for a broad range of detonation wave strengths. (2) The ability to vary the rate at specific pressures has shown that corner turning involves competition between the strong wave that travels roughly in a straight line and growth at low pressure of a new wave that turns corners sharply. (3) The inclusion of a low pressure de-sensitization rate is essential to preserving the dead zone at large times as is observed.
The Piece Wise Linear Reactive Flow Model
Vitello, P; Souers, P C
2005-08-18
For non-ideal explosives a wide range of behavior is observed in experiments dealing with differing sizes and geometries. A predictive detonation model must be able to reproduce many phenomena including such effects as: variations in the detonation velocity with the radial diameter of rate sticks; slowing of the detonation velocity around gentle corners; production of dead zones for abrupt corner turning; failure of small diameter rate sticks; and failure for rate sticks with sufficiently wide cracks. Most models have been developed to explain one effect at a time. Often, changes are made in the input parameters used to fit each succeeding case with the implication that this is sufficient for the model to be valid over differing regimes. We feel that it is important to develop a model that is able to fit experiments with one set of parameters. To address this we are creating a new generation of models that are able to produce better fitting to individual data sets than prior models and to simultaneous fit distinctly different regimes of experiments. Presented here are details of our new Piece Wise Linear reactive flow model applied to LX-17.
Dilatonic non-linear sigma models and Ricci flow extensions
NASA Astrophysics Data System (ADS)
Carfora, M.; Marzuoli, A.
2016-09-01
We review our recent work describing, in terms of the Wasserstein geometry over the space of probability measures, the embedding of the Ricci flow in the renormalization group flow for dilatonic non-linear sigma models.
Thermal and flow analysis subroutines for the SINDA-version 9 computer routine
NASA Technical Reports Server (NTRS)
Oren, J. A.; Williams, D. R.
1973-01-01
Fluid flow analysis, special thermal analysis and input/output capabilities of the MOTAR routine were incorporated into the SINDA routine. All the capabilities were added in the form of user subroutines so that they may be added to different versions of SINDA with a minimum of programmer effort. Two modifications were made to the existing subroutines of SINDA/8 to incorporate the above subroutines. These were: (1) A modification to the preprocessor to permit actual values of array numbers, conductor numbers, node numbers or constant numbers supplied as array data to be converted to relative numbers. (2) Modifications to execution subroutine CNFAST to make it compatible with the radiant interchange user subroutine, RADIR. This modified version of SINDA has been designated SINDA/version 9. A detailed discussion of the methods used for the capabilities added is presented. The modifications for the SINDA subroutines are described, as well as user subroutines. All subroutines added or modified are listed.
Many-core graph analytics using accelerated sparse linear algebra routines
NASA Astrophysics Data System (ADS)
Kozacik, Stephen; Paolini, Aaron L.; Fox, Paul; Kelmelis, Eric
2016-05-01
Graph analytics is a key component in identifying emerging trends and threats in many real-world applications. Largescale graph analytics frameworks provide a convenient and highly-scalable platform for developing algorithms to analyze large datasets. Although conceptually scalable, these techniques exhibit poor performance on modern computational hardware. Another model of graph computation has emerged that promises improved performance and scalability by using abstract linear algebra operations as the basis for graph analysis as laid out by the GraphBLAS standard. By using sparse linear algebra as the basis, existing highly efficient algorithms can be adapted to perform computations on the graph. This approach, however, is often less intuitive to graph analytics experts, who are accustomed to vertex-centric APIs such as Giraph, GraphX, and Tinkerpop. We are developing an implementation of the high-level operations supported by these APIs in terms of linear algebra operations. This implementation is be backed by many-core implementations of the fundamental GraphBLAS operations required, and offers the advantages of both the intuitive programming model of a vertex-centric API and the performance of a sparse linear algebra implementation. This technology can reduce the number of nodes required, as well as the run-time for a graph analysis problem, enabling customers to perform more complex analysis with less hardware at lower cost. All of this can be accomplished without the requirement for the customer to make any changes to their analytics code, thanks to the compatibility with existing graph APIs.
Linear instability of plane Couette and Poiseuille flows
NASA Astrophysics Data System (ADS)
Chefranov, S. G.; Chefranov, A. G.
2016-05-01
It is shown that linear instability of plane Couette flow can take place even at finite Reynolds numbers Re > Reth ≈ 139, which agrees with the experimental value of Reth ≈ 150 ± 5 [16, 17]. This new result of the linear theory of hydrodynamic stability is obtained by abandoning traditional assumption of the longitudinal periodicity of disturbances in the flow direction. It is established that previous notions about linear stability of this flow at arbitrarily large Reynolds numbers relied directly upon the assumed separation of spatial variables of the field of disturbances and their longitudinal periodicity in the linear theory. By also abandoning these assumptions for plane Poiseuille flow, a new threshold Reynolds number Reth ≈ 1035 is obtained, which agrees to within 4% with experiment—in contrast to 500% discrepancy for the previous estimate of Reth ≈ 5772 obtained in the framework of the linear theory under assumption of the "normal" shape of disturbances [2].
Elastic capsule deformation in general irrotational linear flows
Szatmary, Alex C.; Eggleton, Charles D.
2012-01-01
Knowledge of the response of elastic capsules to imposed fluid flow is necessary for predicting deformation and motion of biological cells and synthetic capsules in microfluidic devices and in the microcirculation. Capsules have been studied in shear, planar extensional, and axisymmetric extensional flows. Here, the flow gradient matrix of a general irrotational linear flow is characterized by two parameters, its strain rate, defined as the maximum of the principal strain rates, and by a new term, q, the difference in the two lesser principal strain rates, scaled by the maximum principal strain rate; this characterization is valid for ellipsoids in irrotational linear flow, and it gives good results for spheres in general linear flows at low capillary numbers. We demonstrate that deformable non-spherical particles align with the principal axes of an imposed irrotational flow. Thus, it is most practical to model deformation of non-spherical particles already aligned with the flow, rather than considering each arbitrary orientation. Capsule deformation was modeled for a sphere, a prolate spheroid, and an oblate spheroid, subjected to combinations of uniaxial, biaxial, and planar extensional flows; modeling was performed using the immersed boundary method. The time response of each capsule to each flow was found, as were the steady-state deformation factor, mean strain energy, and surface area. For a given capillary number, planar flows led to more deformation than uniaxial or biaxial extensional flows. Capsule behavior in all cases was bounded by the response of capsules to uniaxial, biaxial, and planar extensional flow. PMID:23426110
Linear Stability Analysis of Couette Flow with a Porous Wall
NASA Astrophysics Data System (ADS)
Tilton, Nils; Cortelezzi, Luca
2006-11-01
It is well known that plane Couette flow in a channel with perfectly smooth, impermeable walls is linearly stable for all Reynolds numbers. Little attention has been given in literature to the stability of plane Couette flow when at least one of the walls is porous. In this study, we consider a channel delimited by an impermeable moving wall, which drives the flow, and a stationary, rigid, homogeneous, isotropic, porous block. We perform a three-dimensional linear stability analysis of the fully developed laminar flow in both the channel and the porous block. We restrict the study to sufficiently small permeabilities in order to neglect inertial effects in the porous flow. We solve the coupled linear stability problem, arising from the adjacent channel and porous flows, using a spectral collocation technique. The linear stability analysis takes account of the coupling between the two disturbance fields through boundary conditions recently derived by Ochoa-Tapia and Whitaker (Int. J. Heat Mass Transfer, 38, 1995). We find that Couette flow over a permeable wall is no longer absolutely stable. While the critical Reynolds number tends to infinity as the permeability tends to zero, it decreases drastically for higher permeabilities. We also find a new channel mode and new class of modes in the porous region. We compare and discuss these results in terms of the recently published results of a three-dimensional linear stability analysis of a channel flow with porous walls (Tilton and Cortelezzi, Phys. Fluids 18, 051702, 2006).
Planning Student Flow with Linear Programming: A Tunisian Case Study.
ERIC Educational Resources Information Center
Bezeau, Lawrence
A student flow model in linear programming format, designed to plan the movement of students into secondary and university programs in Tunisia, is described. The purpose of the plan is to determine a sufficient number of graduating students that would flow back into the system as teachers or move into the labor market to meet fixed manpower…
Two-dimensional motion of Brownian swimmers in linear flows.
Sandoval, Mario; Jimenez, Alonso
2016-03-01
The motion of viruses and bacteria and even synthetic microswimmers can be affected by thermal fluctuations and by external flows. In this work, we study the effect of linear external flows and thermal fluctuations on the diffusion of those swimmers modeled as spherical active (self-propelled) particles moving in two dimensions. General formulae for their mean-square displacement under a general linear flow are presented. We also provide, at short and long times, explicit expressions for the mean-square displacement of a swimmer immersed in three canonical flows, namely, solid-body rotation, shear and extensional flows. These expressions can now be used to estimate the effect of external flows on the displacement of Brownian microswimmers. Finally, our theoretical results are validated by using Brownian dynamics simulations. PMID:26428909
Transition to turbulence for flows without linear criticality
NASA Astrophysics Data System (ADS)
Nagata, Masato
2010-12-01
It is well known that plane Couette flow (PCF) and pipe flow (PF) are linearly stable against arbitrary three-dimensional perturbations at any finite Reynolds number, so that transitions from the basic laminar states, if they exist, must be abrupt. Due to this lack of linear criticality, weakly nonlinear analysis does not work in general and numerical approaches must be resorted to. It is only recently that non-trivial nonlinear states for these flows have been discovered numerically at finite Reynolds number as solutions bifurcating from infinity. The onset of turbulence in a subcritical transition is believed to be related to the appearance of steady/travelling wave states caused by disturbances of finite amplitude that take the flows out of the basin of attraction of the laminar state in phase space. In this paper, we introduce other flows that, in a similar way to PCF and PF, exhibit no linear critical point for the laminar states, namely flow in a square duct and sliding Couette flow in an annulus with a certain range of gap ratio. We shall show our recent numerical investigations on these flows where nonlinear travelling wave states are found for the first time by a homotopy approach. We believe that these states constitute the skeleton around which a time-dependent trajectory in the phase space is organized and help in understanding non-equilibrium turbulent processes.
Fast linear solvers for variable density turbulent flows
NASA Astrophysics Data System (ADS)
Pouransari, Hadi; Mani, Ali; Darve, Eric
2015-11-01
Variable density flows are ubiquitous in variety of natural and industrial systems. Two-phase and multi-phase flows in natural and industrial processes, astrophysical flows, and flows involved in combustion processes are such examples. For an ideal gas subject to low-Mach approximation, variations in temperature can lead to a non-uniform density field. In this work, we consider radiatively heated particle-laden turbulent flows as an example application in which density variability is resulted from inhomogeneities in the heat absorption by an inhomogeneous particle field. Under such conditions, the divergence constraint of the fluid is enforced through a variable coefficient Poisson equation. Inversion of the discretized variable coefficient Poisson operator is difficult using the conventional linear solvers as the size of the problem grows. We apply a novel hierarchical linear solve algorithm based on low-rank approximations. The proposed linear solver could be applied to variety of linear systems arising from discretized partial differential equations. It can be used as a standalone direct-solver with tunable accuracy and linear complexity, or as a high-accuracy pre-conditioner in conjunction with other iterative methods.
Non-linear system identification in flow-induced vibration
Spanos, P.D.; Zeldin, B.A.; Lu, R.
1996-12-31
The paper introduces a method of identification of non-linear systems encountered in marine engineering applications. The non-linearity is accounted for by a combination of linear subsystems and known zero-memory non-linear transformations; an equivalent linear multi-input-single-output (MISO) system is developed for the identification problem. The unknown transfer functions of the MISO system are identified by assembling a system of linear equations in the frequency domain. This system is solved by performing the Cholesky decomposition of a related matrix. It is shown that the proposed identification method can be interpreted as a {open_quotes}Gram-Schmidt{close_quotes} type of orthogonal decomposition of the input-output quantities of the equivalent MISO system. A numerical example involving the identification of unknown parameters of flow (ocean wave) induced forces on offshore structures elucidates the applicability of the proposed method.
Linear models for river flow routing on large catchments
NASA Astrophysics Data System (ADS)
Liang, G. C.; Nash, J. E.
1988-11-01
Following a brief review of the place of linear input-output models in applied hydrology, the algebraic analysis of multiple input single output linear systems is presented and applied in the context of flood routing on the Changjiang (Yangtze River) in China. Two different stretches of the river and one tributary catchment are chosen and the outflows are forecast in terms of observed flows at the upper ends of the river reaches and rainfall on the intervening catchment. It is shown that very high accuracy indeed can be obtained with multiple input linear models whether applied to the total flows and rainfall or to the departures in these quantities from their seasonal expectations. The paper concludes with some analysis of the residual errors which could provide the basis of an updating procedure if the linear models were used for forecasting purposes.
Linear stability analysis of swirling turbulent flows with turbulence models
NASA Astrophysics Data System (ADS)
Gupta, Vikrant; Juniper, Matthew
2013-11-01
In this paper, we consider the growth of large scale coherent structures in turbulent flows by performing linear stability analysis around a mean flow. Turbulent flows are characterized by fine-scale stochastic perturbations. The momentum transfer caused by these perturbations affects the development of larger structures. Therefore, in a linear stability analysis, it is important to include the perturbations' influence. One way to do this is to include a turbulence model in the stability analysis. This is done in the literature by using eddy viscosity models (EVMs), which are first order turbulence models. We extend this approach by using second order turbulence models, in this case explicit algebraic Reynolds stress models (EARSMs). EARSMs are more versatile than EVMs, in that they can be applied to a wider range of flows, and could also be more accurate. We verify our EARSM-based analysis by applying it to a channel flow and then comparing the results with those from an EVM-based analysis. We then apply the EARSM-based stability analysis to swirling pipe flows and Taylor-Couette flows, which demonstrates the main benefit of EARSM-based analysis. This project is supported by EPSRC and Rolls-Royce through a Dorothy Hodgkin Research Fellowship.
Application of linear stability theory in laminar flow design
NASA Technical Reports Server (NTRS)
Iyer, Venkit; Spall, Robert
1991-01-01
The linear stability of fully three-dimensional supersonic boundary layers formed over swept-wing configurations is investigated using a modified version of the linear stability code COSAL. Configurations studied include a highly swept leading-edge model to be utilized for transition studies in the LARC Low-disturbance Mach 3.5 Pilot Tunnel. The model is a representation of the leading edge of a laminar flow control wing for the F-16XL aircraft. In addition, the region over a laminar flow control glove fitted on the midportion of an F-16XL wing was studied. For each configuration, estimates of the location of the onset of transition were computed using linear stability theory and the e exp N method. The effectiveness of suction in stabilizing the boundary layer over the F-16XL wing glove was also investigated.
On the linear stability of compressible plane Couette flow
NASA Technical Reports Server (NTRS)
Duck, Peter W.; Erlebacher, Gordon; Hussaini, M. Yousuff
1991-01-01
The linear stability of compressible plane Couette flow is investigated. The correct and proper basic velocity and temperature distributions are perturbed by a small amplitude normal mode disturbance. The full small amplitude disturbance equations are solved numerically at finite Reynolds numbers, and the inviscid limit of these equations is then investigated in some detail. It is found that instability can occur, although the stability characteristics of the flow are quite different from unbounded flows. The effects of viscosity are also calculated, asymptotically, and shown to have a stabilizing role in all the cases investigated. Exceptional regimes to the problem occur when the wavespeed of the disturbances approaches the velocity of either of the walls, and these regimes are also analyzed in some detail. Finally, the effect of imposing radiation-type boundary conditions on the upper (moving) wall (in place of impermeability) is investigated, and shown to yield results common to both bounded and unbounded flows.
Linearized compressible-flow theory for sonic flight speeds
NASA Technical Reports Server (NTRS)
Heaslet, Max A; Lomax, Harvard; Spreiter, John R
1950-01-01
The partial differential equation for the perturbation velocity potential is examined for free-stream Mach numbers close to and equal to one. It is found that, under the assumptions of linearized theory, solutions can be found consistent with the theory for lifting-surface problems both in stationary three-dimensional flow and in unsteady two-dimensional flow. Several examples are solved including a three dimensional swept-back wing and two dimensional harmonically-oscillating wing, both for a free stream Mach number equal to one. Momentum relations for the evaluation of wave and vortex drag are also discussed. (author)
Piecewise linear manifolds: Einstein metrics and Ricci flows
NASA Astrophysics Data System (ADS)
Schrader, Robert
2016-05-01
This article provides an attempt to extend concepts from the theory of Riemannian manifolds to piecewise linear (p.l.) spaces. In particular we propose an analogue of the Ricci tensor, which we give the name of an Einstein vector field. On a given set of p.l. spaces we define and discuss (normalized) Einstein flows. p.l. Einstein metrics are defined and examples are provided. Criteria for flows to approach Einstein metrics are formulated. Second variations of the total scalar curvature at a specific Einstein space are calculated. Dedicated to Ludwig Faddeev on the occasion of his 80th birthday.
Linear Stability Analysis of a Channel Flow with Porous Walls
NASA Astrophysics Data System (ADS)
Tilton, Nils
2005-11-01
This study is motivated by the extensive use of wall-transpiration in numerical studies related to inhibition and control of wall-turbulence. In general, wall-transpiration has been implemented by providing the wall-normal velocity and imposing a no-slip condition on the wall-tangential velocity. Physically, however, the pores cannot be infinitesimally small and, consequently, it is important to address how the presence of the pores affects the slip velocity at the wall and the stability of the boundary layer. Moreover, our work is motivated by the existence of only few studies on the linear stability of channels with porous walls. Our study considers a parallel-plate channel with porous walls such that a longitudinal pressure gradient induces a laminar flow in both the open channel region and the porous walls. Simplified counterparts to the Orr-Sommerfeld and Squire equations are derived for the porous regions that are valid for small permeablities. The linear stability analysis takes account of the coupling between the three disturbance fields through boundary conditions recently derived by Ochoa-Tapia and Whitaker (Int. J. Heat Mass Transfer, Vol. 38, 1995, pp 2635-2646). The resulting Orr-Sommerfeld spectrum and eigenfunctions reduce to those for Poiseuille flow as the permeability of the walls tends to zero, but are altered for greater values. We discuss symmetrical flows where parameters at both porous walls are identical as well as skewed flows where parameters at the two walls differ.
Linear and radial flow targets for characterizing downhole flow in perforations
Deo, M. ); Tariq, S.M. ); Halleck, P.M. )
1989-08-01
Two types of sandstone targets are commonly used to test flow efficiency of shaped-charge jet perforations: linear targets, in which flow enters only the unperforated end of the cylindrical sample, and radial targets, in which flow enters through the end and sides of the sample. To determine which of these targets best represents downhole conditions, the flow distribution along the length of a perforation has been studied by three-dimensional (3D) finite-element analyses. Linear and radial laboratory targets have been compared with downhole perforations under varying conditions. For ideal perforations, the low-shot-density (LSD) case is adequately represented by the radial target, while the high-shot-density (HSD) case falls between the two targets. With realistic crushed and damaged zones, the HSD closely matches the linear target, and the LSD case falls between the two targets.
Complex Dynamics of Compound Vesicles in Linear Flow
NASA Astrophysics Data System (ADS)
Levant, Michael; Steinberg, Victor
2014-04-01
We report first experimental observations of dynamics of compound vesicles in linear flow realized in a microfluidic four-roll mill. We show that while a compound vesicle undergoes the same main tank-treading, trembling (TR), and tumbling regimes, its dynamics are far richer and more complex than that of unilamellar vesicles. A new swinging motion of the inner vesicle is found in TR in accord with simulations. The inner and outer vesicles can exist simultaneously in different dynamical regimes and can undergo either synchronized or unsynchronized motions depending on the filling factor. A compound vesicle can be used as a physical model to study white blood cell dynamics in flow similar to a unilamellar vesicle used successfully to model anucleate cells.
Complex dynamics of compound vesicles in linear flow.
Levant, Michael; Steinberg, Victor
2014-04-01
We report first experimental observations of dynamics of compound vesicles in linear flow realized in a microfluidic four-roll mill. We show that while a compound vesicle undergoes the same main tank-treading, trembling (TR), and tumbling regimes, its dynamics are far richer and more complex than that of unilamellar vesicles. A new swinging motion of the inner vesicle is found in TR in accord with simulations. The inner and outer vesicles can exist simultaneously in different dynamical regimes and can undergo either synchronized or unsynchronized motions depending on the filling factor. A compound vesicle can be used as a physical model to study white blood cell dynamics in flow similar to a unilamellar vesicle used successfully to model anucleate cells.
The Linear Study of Zonally Asymmetric Barotropic Flows.
NASA Astrophysics Data System (ADS)
Zhang, Zuojun
Available from UMI in association with The British Library. The loss of orthogonality between unstable normal modes is general for any kind of eigen-analysis. In particular for an observed climatological mean flow this is found to be very significant for the development of perturbations. A small perturbation can have a very large projection onto the most unstable normal mode. The adjoint eigenmode is most efficient at exciting the normal mode. The "gain" on projection is described by the projectibility. In general, growthrate and frequency information should be augmented with the projectibility and eigenvectors should be augmented by the corresponding adjoint eigenvectors. For the 300mb January climatological mean flow, the maximum projectibility is found to be 7.8 and the adjoint mode corresponding to the most unstable normal mode has large amplitude over the subtropical Indian Ocean and southeast Asia. The adjoint mode when used as an initial perturbation yields an energy increase of a factor of 50 within 10 days even when a damping is added to make the system stable. Both the initial value problems and forcing problems show that the linear barotropic vorticity equation gives important ideas on atmospheric low-frequency variability and the role of the tropics. The sensitivity of linear analysis to details of flow is studied. It is found that the instability is much more sensitive to the strength of the zonal flow component than to that of the wave components. The variation of leading unstable modes with respect to the strength of the waves is easily traced, as it is also in a simple system which contains only a zonal flow and a wave. Instability depends upon the assumption of the maintenance of the basic state. The sensitivity to basic states maintained by a divergent wind forcing and an equivalent orographic forcing are studied. It is found that the instability is more sensitive to the equivalent orographic forcing than to the divergent wind forcing. The
Flow discharge prediction in compound channels using linear genetic programming
NASA Astrophysics Data System (ADS)
Azamathulla, H. Md.; Zahiri, A.
2012-08-01
SummaryFlow discharge determination in rivers is one of the key elements in mathematical modelling in the design of river engineering projects. Because of the inundation of floodplains and sudden changes in river geometry, flow resistance equations are not applicable for compound channels. Therefore, many approaches have been developed for modification of flow discharge computations. Most of these methods have satisfactory results only in laboratory flumes. Due to the ability to model complex phenomena, the artificial intelligence methods have recently been employed for wide applications in various fields of water engineering. Linear genetic programming (LGP), a branch of artificial intelligence methods, is able to optimise the model structure and its components and to derive an explicit equation based on the variables of the phenomena. In this paper, a precise dimensionless equation has been derived for prediction of flood discharge using LGP. The proposed model was developed using published data compiled for stage-discharge data sets for 394 laboratories, and field of 30 compound channels. The results indicate that the LGP model has a better performance than the existing models.
Linear stability of cylindrical Couette flow in the convection regime
NASA Astrophysics Data System (ADS)
Ali, Mohamed E.; McFadden, G. B.
2005-05-01
The instability of steady circular Couette flow with radial heating across a vertically oriented annulus with a rotating inner cylinder and a stationary outer cylinder is investigated using a linear stability analysis. The convection regime base flow is developed for an infinite aspect ratio geometry and constant fluid properties with buoyancy included through the Boussinesq approximation. The base flow is characterized by a dimensionless stratification parameter γ that is proportional to the vertical temperature gradient. Critical stability boundaries are calculated for this assumed base flow with respect to both toroidal and helical disturbances. The numerical investigation is primarily restricted to a radius ratio of 0.6 at a Prandtl number of 100. Critical stability boundaries in Taylor-Grashof number space are presented for two values of the stratification parameter γ (4 and 13). The results follow the development of critical stability from Taylor cells at small Grashof numbers up to a maximum Grashof number used in this calculation of 20 000 and 80 000 for γ =4 and 13, respectively. Results show that increasing the stratification parameter stabilizes the isothermal Taylor vortices, followed by a destabilization at higher azimuthal mode numbers (n>0). The results also show that for γ =4 (close to the conduction regime), two modes are obtained: one is axisymmetric and the other is nonaxisymmetric. However, for the convection regime (large γ) six asymmetric modes are obtained. Finally, the disturbance wavelength, phase speed, and spiral inclination angle are presented as a function of the critical Grashof number for the stratification parameters considered in this work.
Linear Instability Analysis for Toroidal Plasma Flow Equilibria
NASA Astrophysics Data System (ADS)
Varadarajan, V.; Miley, G. H.
1996-02-01
The non-self-adjoint Frieman-Rotenberg equation for the linear ideal magnetohydrodynamic modes in flow equilibria is numerically solved in shaped finite-aspect ratio axisymmetric tokamak geometry. A quadratic form is derived from this equation, and, in particular, the self-adjoint force operator with finite toroidal rotation is cast into a manifestly self-adjoint form. The toroidal rotational velocities in the subsonic regime are considered. The quadratic form is discretized by a mixed finite-element procedure in the radial direction and by Fourier modes in the periodic directions. The mode frequency of the unstable mode is located by root searching, and the final root refinement is obtained by a rapid inverse iteration procedure for complex roots. The real part of then= 1 internal kink mode scales linearly with the plasma rotation, and the imaginary part of the unstable mode is at least an order of magnitude higher in the presence of high plasma rotation velocities. The kink mode is also found to be unstable at high rotation velocities, even when the axis safety factor is above unity. The instability characterized by these features is termed here as the "centrifugal" instability. The centrifugal kink instability would have finite real parts, as shown by the plasma rotation observed in plasma devices such as tokamaks. To explain the features of this mode, the plasma rotation should be taken into account. Therein lies the usefulness of the computational analysis presented here.
Linearized reduced-order models for subsurface flow simulation
NASA Astrophysics Data System (ADS)
Cardoso, M. A.; Durlofsky, L. J.
2010-02-01
A trajectory piecewise linearization (TPWL) procedure for the reduced-order modeling of two-phase flow in subsurface formations is developed and applied. The method represents new pressure and saturation states using linear expansions around states previously simulated and saved during a series of preprocessing training runs. The linearized representation is projected into a low-dimensional space, with the projection matrix constructed through proper orthogonal decomposition of the states determined during the training runs. The TPWL model is applied to two example problems, containing 24,000 and 79,200 grid blocks, which are characterized by heterogeneous permeability descriptions. Extensive test simulations are performed for both models. It is shown that the TPWL model provides accurate results when the controls (bottom hole pressures of the production wells in this case) applied in test simulations are within the general range of the controls applied in the training runs, even though the well pressure schedules for the test runs can differ significantly from those of the training runs. This indicates that the TPWL model displays a reasonable degree of robustness. Runtime speedups using the procedure are very significant-a factor of 100-2000 (depending on model size and whether or not mass balance error is computed at every time step) for the cases considered. The preprocessing overhead required by the TPWL procedure is the equivalent of about four high-fidelity simulations. Finally, the TPWL procedure is applied to a computationally demanding multiobjective optimization problem, for which the Pareto front is determined. Limited high-fidelity simulations demonstrate the accuracy and applicability of TPWL for this optimization. Future work should focus on error estimation and on stabilizing the method for large models with significant density differences between phases.
NASA Astrophysics Data System (ADS)
Chen, Y.-M.; Koniges, A. E.; Anderson, D. V.
1989-10-01
The biconjugate gradient method (BCG) provides an attractive alternative to the usual conjugate gradient algorithms for the solution of sparse systems of linear equations with nonsymmetric and indefinite matrix operators. A preconditioned algorithm is given, whose form resembles the incomplete L-U conjugate gradient scheme (ILUCG2) previously presented. Although the BCG scheme requires the storage of two additional vectors, it converges in a significantly lesser number of iterations (often half), while the number of calculations per iteration remains essentially the same.
Detection of linear ego-acceleration from optic flow.
Festl, Freya; Recktenwald, Fabian; Yuan, Chunrong; Mallot, Hanspeter A
2012-07-20
Human observers are able to estimate various ego-motion parameters from optic flow, including rotation, translational heading, time-to-collision (TTC), time-to-passage (TTP), etc. The perception of linear ego-acceleration or deceleration, i.e., changes of translational velocity, is less well understood. While time-to-passage experiments indicate that ego-acceleration is neglected, subjects are able to keep their (perceived) speed constant under changing conditions, indicating that some sense of ego-acceleration or velocity change must be present. In this paper, we analyze the relation of ego-acceleration estimates and geometrical parameters of the environment using simulated flights through cylindrical and conic (narrowing or widening) corridors. Theoretical analysis shows that a logarithmic ego-acceleration parameter, called the acceleration rate ρ, can be calculated from retinal acceleration measurements. This parameter is independent of the geometrical layout of the scene; if veridical ego-motion is known at some instant in time, acceleration rate allows updating of ego-motion without further depth-velocity calibration. Results indicate, however, that subjects systematically confuse ego-acceleration with corridor narrowing and ego-deceleration with corridor widening, while veridically judging ego-acceleration in straight corridors. We conclude that judgments of ego-acceleration are based on first-order retinal flow and do not make use of acceleration rate or retinal acceleration.
Nonaxisymmetric linear instability of cylindrical magnetohydrodynamic Taylor-Couette flow.
Child, Adam; Kersalé, Evy; Hollerbach, Rainer
2015-09-01
We consider the nonaxisymmetric modes of instability present in Taylor-Couette flow under the application of helical magnetic fields, mainly for magnetic Prandtl numbers close to the inductionless limit, and conduct a full examination of marginal stability in the resulting parameter space. We allow for the azimuthal magnetic field to be generated by a combination of currents in the inner cylinder and fluid itself and introduce a parameter governing the relation between the strength of these currents. A set of governing eigenvalue equations for the nonaxisymmetric modes of instability are derived and solved by spectral collocation with Chebyshev polynomials over the relevant parameter space, with the resulting instabilities examined in detail. We find that by altering the azimuthal magnetic field profiles the azimuthal magnetorotational instability, nonaxisymmetric helical magnetorotational instability, and Tayler instability yield interesting dynamics, such as different preferred mode types and modes with azimuthal wave number m>1. Finally, a comparison is given to the recent WKB analysis performed by Kirillov et al. [Kirillov, Stefani, and Fukumoto, J. Fluid Mech. 760, 591 (2014)JFLSA70022-112010.1017/jfm.2014.614] and its validity in the linear regime.
Linear stability of general magnetically insulated electron flow
NASA Astrophysics Data System (ADS)
Swegle, J. A.; Mendel, C. W., Jr.; Seidel, D. B.; Quintenz, J. P.
1984-03-01
A linear stability theory for magnetically insulated systems was formulated by linearizing the general 3-D, time dependent theory of Mendel, Seidel, and Slut. It is found that, case of electron trajectories which are nearly laminar, with only small transverse motion, several suggestive simplifications occur in the eigenvalue equations.
Linear stability of general magnetically insulated electron flow
Swegle, J.A.; Mendel, C.W. Jr.; Seidel, D.B.; Quintenz, J.P.
1984-01-01
We have formulated a linear stability theory for magnetically insulated systems by linearizing the general 3-D, time-dependent theory of Mendel, Seidel, and Slutz. In the physically interesting case of electron trajectories which are nearly laminar, with only small transverse motion, we have found that several suggestive simplifications occur in the eigenvalue equations.
Linear stability of compressible Taylor-Couette flow
NASA Technical Reports Server (NTRS)
Kao, Kai-Hsiung; Chow, Chuen-Yen
1992-01-01
A temporal stability analysis of compressible Taylor-Couette flow is presented. The viscous flow studied in this paper is contained between two concentric cylinders of infinite length, which are rotating with different angular velocities and are kept at different surface temperatures. The effects of differential rotation and temperature difference on the stability of Taylor-Couette flow are contrasted for a range of Mach numbers ranging from incompressible to Mach 3.0. The relative motion of the cylinders dramatically affects the characteristics of the Couette flow at the onset of instability. The flow is stabilized or destabilized depending upon the temperature ratio and speeds of the two cylinders. Independent of Mach number and temperature ratio, increasing Reynolds number generally promotes a destabilizing effect, indicating the inviscid nature of the Taylor-Couette flow.
Torres, Marta
2014-01-31
In November 2012, Oregon State University initiated the project entitled: Application of Crunch-Flow routines to constrain present and past carbon fluxes at gas-hydrate bearing sites. Within this project we developed Crunch-Flow based modeling modules that include important biogeochemical processes that need to be considered in gas hydrate environments. Our modules were applied to quantify carbon cycling in present and past systems, using data collected during several DOE-supported drilling expeditions, which include the Cascadia margin in US, Ulleung Basin in South Korea, and several sites drilled offshore India on the Bay of Bengal and Andaman Sea. Specifically, we completed modeling efforts that: 1) Reproduce the compositional and isotopic profiles observed at the eight drilled sites in the Ulleung Basin that constrain and contrast the carbon cycling pathways at chimney (high methane flux) and non-chimney sites (low methane, advective systems); 2) Simulate the Ba record in the sediments to quantify the past dynamics of methane flux in the southern Hydrate Ridge, Cascadia margin; and 3) Provide quantitative estimates of the thickness of individual mass transport deposits (MTDs), time elapsed after the MTD event, rate of sulfate reduction in the MTD, and time required to reach a new steady state at several sites drilled in the Krishna-Godavari (K-G) Basin off India. In addition we developed a hybrid model scheme by coupling a home-made MATLAB code with CrunchFlow to address the methane transport and chloride enrichment at the Ulleung Basins chimney sites, and contributed the modeling component to a study focusing on pore-scale controls on gas hydrate distribution in sediments from the Andaman Sea. These efforts resulted in two manuscripts currently under review, and contributed the modeling component of another pare, also under review. Lessons learned from these efforts are the basis of a mini-workshop to be held at Oregon State University (Feb 2014) to instruct
Enhancing the linear flow of fine granules through the addition of elongated particles
Guo, Zhiguo; Chen, Xueli; Xu, Yang; Liu, Haifeng
2015-01-01
Sandglasses have been used to record time for thousands of years because of their constant flow rates; however, they now are drawing attention for their substantial scientific importance and extensive industrial applications. The presence of elongated particles in a binary granular system is believed to result in undesired flow because their shape implies a larger resistance to flow. However, our experiments demonstrate that the addition of elongated particles can substantially reduce the flow fluctuation of fine granules and produce a stable linear flow similar to that in an hourglass. On the basis of experimental data and previous reports of flow dynamics, we observed that the linear flow is driven by the “needle particle effect,” including flow orientation, reduced agglomeration, and local perturbation. This phenomenon is observed in several binary granular systems, including fine granules and secondary elongated particles, which demonstrates that our simple method can be widely applied to the accurate measurement of granular flows in industry. PMID:26551736
Two-Dimensional, Supersonic, Linearized Flow with Heat Addition
NASA Technical Reports Server (NTRS)
Lomax, Harvard
1959-01-01
Calculations are presented for the forces on a thin supersonic wing underneath which the air is heated. The analysis is limited principally to linearized theory but nonlinear effects are considered. It is shown that significant advantages to external heating would exist if the heat were added well below and ahead of the wing.
Linear coupling of acoustic and cyclotron waves in plasma flows
Rogava, Andria; Gogoberidze, Grigol
2005-05-15
It is found that in magnetized electrostatic plasma flows the velocity shear couples ion-acoustic waves with ion-cyclotron waves and leads, under favorable conditions, to their efficient reciprocal transformations. It is shown that in a two-dimensional setup this coupling has a remarkable feature: it is governed by equations that are mathematically equal to the ones describing coupling of sound waves with internal gravity waves [Rogava and Mahajan, Phys. Rev. E 55, 1185 (1997)] in neutral fluids. For flows with low shearing rates a fully analytic, quantitative description of the coupling efficiency, based on a noteworthy quantum-mechanical analogy, is given and transformation coefficients are calculated.
A higher order panel method for linearized supersonic flow
NASA Technical Reports Server (NTRS)
Ehlers, F. E.; Epton, M. A.; Johnson, F. T.; Magnus, A. E.; Rubbert, P. E.
1979-01-01
The basic integral equations of linearized supersonic theory for an advanced supersonic panel method are derived. Methods using only linear varying source strength over each panel or only quadratic doublet strength over each panel gave good agreement with analytic solutions over cones and zero thickness cambered wings. For three dimensional bodies and wings of general shape, combined source and doublet panels with interior boundary conditions to eliminate the internal perturbations lead to a stable method providing good agreement experiment. A panel system with all edges contiguous resulted from dividing the basic four point non-planar panel into eight triangular subpanels, and the doublet strength was made continuous at all edges by a quadratic distribution over each subpanel. Superinclined panels were developed and tested on s simple nacelle and on an airplane model having engine inlets, with excellent results.
NASA Technical Reports Server (NTRS)
Clark, William S.; Hall, Kenneth C.
1994-01-01
A linearized Euler solver for calculating unsteady flows in turbomachinery blade rows due to both incident gusts and blade motion is presented. The model accounts for blade loading, blade geometry, shock motion, and wake motion. Assuming that the unsteadiness in the flow is small relative to the nonlinear mean solution, the unsteady Euler equations can be linearized about the mean flow. This yields a set of linear variable coefficient equations that describe the small amplitude harmonic motion of the fluid. These linear equations are then discretized on a computational grid and solved using standard numerical techniques. For transonic flows, however, one must use a linear discretization which is a conservative linearization of the non-linear discretized Euler equations to ensure that shock impulse loads are accurately captured. Other important features of this analysis include a continuously deforming grid which eliminates extrapolation errors and hence, increases accuracy, and a new numerically exact, nonreflecting far-field boundary condition treatment based on an eigenanalysis of the discretized equations. Computational results are presented which demonstrate the computational accuracy and efficiency of the method and demonstrate the effectiveness of the deforming grid, far-field nonreflecting boundary conditions, and shock capturing techniques. A comparison of the present unsteady flow predictions to other numerical, semi-analytical, and experimental methods shows excellent agreement. In addition, the linearized Euler method presented requires one or two orders-of-magnitude less computational time than traditional time marching techniques making the present method a viable design tool for aeroelastic analyses.
Linear stability of circular Couette flow in the limit of small radius ratio
NASA Astrophysics Data System (ADS)
Pearlstein, Arne J.
2005-11-01
In the context of a detailed study of the linear stability of spiral Poiseuille flow at small radius ratio (Cotrell and Pearlstein, J. Fluid Mech., in press), we have shown that in the limiting case of no rotation, annular Poiseuille flow is linearly stable at all Re, provided that the radius ratio lies below a critical value. Here, we consider the other limiting case, of no axial flow, and report a numerical investigation of the stability of circular Couette flow for small radius ratio. The results are compared to experimental work of Theodorsen for a whirling shaft in an unbounded, otherwise quiescent fluid.
Linear flow dynamics near a T/NT interface
NASA Astrophysics Data System (ADS)
Teixeira, Miguel; Silva, Carlos
2011-11-01
The characteristics of a suddenly-inserted T/NT interface separating a homogeneous and isotropic shear-free turbulence region from a non-turbulent flow region are investigated using rapid distortion theory (RDT), taking full account of viscous effects. Profiles of the velocity variances, TKE, viscous dissipation rate, turbulence length scales, and pressure statistics are derived, showing very good agreement with DNS. The normalized inviscid flow statistics at the T/NT interface do not depend on the form of the assumed TKE spectrum. In the non-turbulent region, where the flow is irrotational (except within a thin viscous boundary layer), the dissipation rate decays as z-6, where z is distance from the T/NT interface. The mean pressure exhibits a decrease towards the turbulence due to the associated velocity fluctuations, consistent with the generation of a mean entrainment velocity. The vorticity variance and dissipation rate display large maxima at the T/NT interface due to the existing inviscid discontinuities of the tangential velocity, and these maxima are quantitatively related to the thickness of the viscous boundary layer (VBL). At equilibrium, RDT suggests that the thickness of the T/NT interface scales on the Kolmogorov microscale. We acknowledge the financial support of FCT under Project PTDC/EME-MFE/099636/2008.
Linear system identification of a cold flow circulating fluidized bed
Panday, R; Woerner, B D; Ludlow, J C; Shadle, L J; Boyle, E J
2009-02-01
Knowledge of the solids circulation rate (SCR) is essential to the control and improved performance of a circulating fluidized bed system. In the present work, the noise model is derived using the prediction error method considering process and measurement noises acting on the cold flow circulating fluidized bed (CFCFB) with a cork particulate material. The outputs of the initial model are the total pressure drop across the riser, the pressure drop across the crossover, the pressure drop across the primary cyclone, the total pressure drop across the stand-pipe, the pressure drop across the loop seal, and the SCR. The stochastic estimate of SCR is determined from the noise model using the stochastic pressure drop estimates. The deterministic estimate is obtained through the inputs taken as move air flow, riser aeration, and loop seal fluidization air that are all independent variables of the given setup and under the control of the user. The theory has been developed to convert a complete blackbox model to a grey box model through the output-to-state transformation such that both the models of the CFCFB consists of all these output variables as the states of the system, and only pressure drops across the system as the output measurements. Thus, the final models do not include any fictitious terms and they are defined only in terms of physical parameters of the given system. Both components of SCR are separately analysed. The combined SCR response of both the noise model and deterministic model is compared with the validation data set of this state variable in terms of modelfit, and the results are shown.
Transport equations for linear surface waves with random underlying flows
NASA Astrophysics Data System (ADS)
Bal, Guillaume; Chou, Tom
1999-11-01
We define the Wigner distribution and use it to develop equations for linear surface capillary-gravity wave propagation in the transport regime. The energy density a(r, k) contained in waves propagating with wavevector k at field point r is given by dota(r,k) + nabla_k[U_⊥(r,z=0) \\cdotk + Ω(k)]\\cdotnabla_ra [13pt] \\: hspace1in - (nabla_r\\cdotU_⊥)a - nabla_r(k\\cdotU_⊥)\\cdotnabla_ka = Σ(δU^2) where U_⊥(r, z=0) is a slowly varying surface current, and Ω(k) = √(k^3+k)tanh kh is the free capillary-gravity dispersion relation. Note that nabla_r\\cdotU_⊥(r,z=0) neq 0, and that the surface currents exchange energy density with the propagating waves. When an additional weak random current √\\varepsilon δU(r/\\varepsilon) varying on the scale of k-1 is included, we find an additional scattering term Σ(δU^2) as a function of correlations in δU. Our results can be applied to the study of surface wave energy transport over a turbulent ocean.
Boundary Slip Effects on the Linear Stability of Circular and Spiral Poiseuille Flow
NASA Astrophysics Data System (ADS)
Cotrell, D.; McFadden, G.
2008-11-01
In this work, we consider the effect of boundary slip on the linear stability of various internal flows having boundary curvature. For the case of annular flow, slip can have a small to moderate affect on the linear stability analysis, with results showing that if the linear stability analysis gives a finite transition for no-slip boundary conditions, then the addition of slip can have either a stabilizing or destabilizing effect on the flow depending on the radius ratio. The results also show that for fixed Knudsen number, there is a value of the radius ratio for which there is no difference between linear stability results with and without slip, and that this value of the radius ratio changes with Reynolds number as does the number of crossings (i.e., one crossing for a Reynolds number of zero and two for a Reynolds number of 100). As for the annular special case (i.e., Taylor-Couette flow with μ>2̂), results show that relaxing the no-slip condition on the cylinder walls does not destabilize this flow (i.e., computations still give a critical value of infinity). Similar to these results, for circular Poiseuille flow (i.e., pipe flow) current results show that relaxing the no-slip boundary condition on the cylinder wall does not destabilize the flow.
NASA Astrophysics Data System (ADS)
Chefranov, Sergey; Chefranov, Alexander
2016-04-01
Linear hydrodynamic stability theory for the Hagen-Poiseuille (HP) flow yields a conclusion of infinitely large threshold Reynolds number, Re, value. This contradiction to the observation data is bypassed using assumption of the HP flow instability having hard type and possible for sufficiently high-amplitude disturbances. HP flow disturbance evolution is considered by nonlinear hydrodynamic stability theory. Similar is the case of the plane Couette (PC) flow. For the plane Poiseuille (PP) flow, linear theory just quantitatively does not agree with experimental data defining the threshold Reynolds number Re= 5772 ( S. A. Orszag, 1971), more than five-fold exceeding however the value observed, Re=1080 (S. J. Davies, C. M. White, 1928). In the present work, we show that the linear stability theory conclusions for the HP and PC on stability for any Reynolds number and evidently too high threshold Reynolds number estimate for the PP flow are related with the traditional use of the disturbance representation assuming the possibility of separation of the longitudinal (along the flow direction) variable from the other spatial variables. We show that if to refuse from this traditional form, conclusions on the linear instability for the HP and PC flows may be obtained for finite Reynolds numbers (for the HP flow, for Re>704, and for the PC flow, for Re>139). Also, we fit the linear stability theory conclusion on the PP flow to the experimental data by getting an estimate of the minimal threshold Reynolds number as Re=1040. We also get agreement of the minimal threshold Reynolds number estimate for PC with the experimental data of S. Bottin, et.al., 1997, where the laminar PC flow stability threshold is Re = 150. Rogue waves excitation mechanism in oppositely directed currents due to the PC flow linear instability is discussed. Results of the new linear hydrodynamic stability theory for the HP, PP, and PC flows are published in the following papers: 1. S.G. Chefranov, A
NASA Technical Reports Server (NTRS)
Reed, D. A.; Patrick, M. L.
1985-01-01
The applicability of static data flow architectures to the iterative solution of sparse linear systems of equations is investigated. An analytic performance model of a static data flow computation is developed. This model includes both spatial parallelism, concurrent execution in multiple PE's, and pipelining, the streaming of data from array memories through the PE's. The performance model is used to analyze a row partitioned iterative algorithm for solving sparse linear systems of algebraic equations. Based on this analysis, design parameters for the static data flow architecture as a function of matrix sparsity and dimension are proposed.
NASA Astrophysics Data System (ADS)
Choi, Bernard; Ramírez-San-Juan, Julio C.; Lotfi, Justin; Nelson, J. S.
2006-07-01
Noninvasive blood flow imaging can provide critical information on the state of biological tissue and the efficacy of approaches to treat disease. With laser speckle imaging (LSI), relative changes in blood flow are typically reported, with the assumption that the measured values are on a linear scale. A linear relationship between the measured and actual flow rate values has been suggested. The actual flow rate range, over which this linear relationship is valid, is unknown. Herein we report the linear response range and velocity dynamic range (VDR) of our LSI instrument at two relevant camera integration times. For integration times of 1 and 10 ms, the best case VDR was 80 and 60 dB, respectively, and the worst case VDR was 20 and 50 dB. The best case VDR values were similar to those reported in the literature for optical Doppler tomography. We also demonstrate the potential of LSI for monitoring blood flow dynamics in the rodent dorsal skinfold chamber model. These findings imply that LSI can provide accurate wide-field maps of microvascular blood flow rate dynamics and highlight heterogeneities in flow response to the application of exogenous agents.
Marietti, Y; Debierre, J M; Bock, T M; Kassner, K
2001-06-01
An asymptotic interface equation for directional solidification near the absolute stability limit is extended by a nonlocal term describing a shear flow parallel to the interface. In the long-wave limit considered, the flow acts destabilizing on a planar interface. Moreover, linear stability analysis suggests that the morphology diagram is modified by the flow near onset of the Mullins-Sekerka instability. Via numerical analysis, the bifurcation structure of the system is shown to change. Besides the known hexagonal cells, structures consisting of stripes arise. Due to its symmetry-breaking properties, the flow term induces a lateral drift of the whole pattern, once the instability has become active. The drift velocity is measured numerically and described analytically in the framework of a linear analysis. At large flow strength, the linear description breaks down, which is accompanied by a transition to flow-dominated morphologies which is described in the following paper. Small and intermediate flows lead to increased order in the lattice structure of the pattern, facilitating the elimination of defects. Locally oscillating structures appear closer to the instability threshold with flow than without.
NASA Astrophysics Data System (ADS)
Chagelishvili, George; Hau, Jan-Niklas; Khujadze, George; Oberlack, Martin
2016-08-01
The linear dynamics of perturbations in smooth shear flows covers the transient exchange of energies between (1) the perturbations and the basic flow and (2) different perturbations modes. Canonically, the linear exchange of energies between the perturbations and the basic flow can be described in terms of the Orr and the lift-up mechanisms, correspondingly for two-dimensional (2D) and three-dimensional (3D) perturbations. In this paper the mechanical basis of the linear transient dynamics is introduced and analyzed for incompressible plane constant shear flows, where we consider the dynamics of virtual fluid particles in the framework of plane perturbations (i.e., perturbations with plane surfaces of constant phase) for the 2D and 3D case. It is shown that (1) the formation of a pressure perturbation field is the result of countermoving neighboring sets of incompressible fluid particles in the flow, (2) the keystone of the energy exchange mechanism between the basic flow and perturbations is the collision of fluid particles with the planes of constant pressure in accordance with the classical theory of elastic collision of particles with a rigid wall, making the pressure field the key player in this process, (3) the interplay of the collision process and the shear flow kinematics describes the transient growth of plane perturbations and captures the physics of the growth, and (4) the proposed mechanical picture allows us to reconstruct the linearized Euler equations in spectral space with a time-dependent shearwise wave number, the linearized Euler equations for Kelvin modes. This confirms the rigor of the presented analysis, which, moreover, yields a natural generalization of the proposed mechanical picture of the transient growth to the well-established linear phenomenon of vortex-wave-mode coupling.
Micro-Volume Couette Flow Sample Orientation for Absorbance and Fluorescence Linear Dichroism
Marrington, Rachel; Dafforn, Timothy R.; Halsall, David J.; Rodger, Alison
2004-01-01
Linear dichroism (LD) can be used to study the alignment of absorbing chromophores within long molecules. In particular, Couette flow LD has been used to good effect in probing ligand binding to DNA and to fibrous proteins. This technique has been previously limited by large sample requirements. Here we report the design and application of a new micro-volume Couette flow cell that significantly enhances the potential applications of flow LD spectroscopy by reducing the sample requirements for flow linear dichroism to 25 μL (with concentrations such that the absorbance maximum of the sample in a 1-cm pathlength cuvette is ∼1). The micro-volume Couette cell has also enabled the measurement of fluorescence-detected Couette flow linear dichroism. This new technique enables the orientation of fluorescent ligands to be probed even when their electronic transitions overlap with those of the macromolecule and conversely. The potential of flow-oriented fluorescence dichroism and application of the micro-volume Couette LD cell are illustrated by the collection of data for DNA with minor groove and intercalating ligands: DAPI, Hoechst, and ethidium bromide. As with conventional fluorescence, improved sensitivity compared with absorbance LD is to be expected after instrumentation optimization. PMID:15345576
Calculation of linearized supersonic flow over slender cones of arbitrary cross section
NASA Technical Reports Server (NTRS)
Mascitti, V. R.
1972-01-01
Supersonic linearized conical-flow theory is used to determine the flow over slender pointed cones having horizontal and vertical planes of symmetry. The geometry of the cone cross sections and surface velocities are expanded in Fourier series. The symmetry condition permits the uncoupling of lifting and nonlifting solutions. The present method reduces to Ward's theory for flow over a cone of elliptic cross section. Results are also presented for other shapes. Results by this method diverge for cross-sectional shapes where the maximum thickness is large compared with the minimum thickness. However, even for these slender-body shapes, lower order solutions are good approximations to the complete solution.
Comparison of the Single Molecule Dynamics of Linear and Circular DNAs in Planar Extensional Flows
NASA Astrophysics Data System (ADS)
Li, Yanfei; Hsiao, Kai-Wen; Brockman, Christopher; Yates, Daniel; McKenna, Gregory; Schroeder, Charles; San Francisco, Michael; Kornfield, Julie; Anderson, Rae
2015-03-01
Chain topology has a profound impact on the flow behaviors of single macromolecules. The absence of free ends separates circular polymers from other chain architectures, i.e., linear, star, and branched. In the present work, we study the single chain dynamics of large circular and linear DNA molecules by comparing the relaxation dynamics, steady state coil-stretch transition, and transient molecular individualism behaviors for the two types of macromolecules. To this end, large circular DNA molecules were biologically synthesized and studied in a microfluidic device that has a cross-slot geometry to develop a stagnation point extensional flow. Although the relaxation time of rings scales in the same way as for the linear analog, the circular polymers show quantitatively different behaviors in the steady state extension and qualitatively different behaviors during a transient stretch. The existence of some commonality between these two topologies is proposed. Texas Tech University John R. Bradford Endowment.
NASA Astrophysics Data System (ADS)
Chakraborty, Debadi; Sader, John E.
2015-05-01
Simple bulk liquids such as water are commonly assumed to be Newtonian. While this assumption holds widely, the fluid-structure interaction of mechanical devices at nanometer scales can probe the intrinsic molecular relaxation processes in a surrounding liquid. This was recently demonstrated through measurement of the high frequency (20 GHz) linear mechanical vibrations of bipyramidal nanoparticles in simple liquids [Pelton et al., "Viscoelastic flows in simple liquids generated by vibrating nanostructures," Phys. Rev. Lett. 111, 244502 (2013)]. In this article, we review and critically assess the available constitutive equations for compressible viscoelastic flows in their linear limits—such models are required for analysis of the above-mentioned measurements. We show that previous models, with the exception of a very recent proposal, do not reproduce the required response at high frequency. We explain the physical origin of this recent model and show that it recovers all required features of a linear viscoelastic flow. This constitutive equation thus provides a rigorous foundation for the analysis of vibrating nanostructures in simple liquids. The utility of this model is demonstrated by solving the fluid-structure interaction of two common problems: (1) a sphere executing radial oscillations in liquid, which depends strongly on the liquid compressibility and (2) the extensional mode vibration of bipyramidal nanoparticles in liquid, where the effects of liquid compressibility are negligible. This highlights the importance of shear and compressional relaxation processes, as a function of flow geometry, and the impact of the shear and bulk viscosities on nanometer scale flows.
Linear mechanism of surface gravity wave generation in horizontally sheared flow
Kalashnik, M. V.
2008-01-15
An analysis is presented of a linear mechanism of surface gravity wave generation in a horizontally sheared flow in a fluid layer with free boundary. A free-surface flow of this type is found to be algebraically unstable. The development of instability leads to the formation of surface gravity waves whose amplitude grows with time according to a power law. Flow stability is analyzed by using a nonmodal approach in which the behavior of a spatial Fourier harmonic of a disturbance is considered in a semi-Lagrangian frame of reference moving with the flow. Shear-flow disturbances are divided into two classes (wave and vortex disturbances) depending on the value of potential vorticity. It is shown that vortex disturbances decay with time while the energy of wave disturbances increases indefinitely. Transformation of vortex disturbances into wave ones under strong shear is described.
Linear and nonlinear effect of sheared plasma flow on resistive tearing modes
Hu, Qiming Hu, Xiwei; Yu, Q.
2014-12-15
The effect of sheared plasma flow on the m/n = 2/1 tearing mode is studied numerically (m and n are the poloidal and toroidal mode numbers). It is found that in the linear phase the plasma flow with a weak or moderate shear plays a stabilizing effect on tearing mode. However, the mode is driven to be more unstable by sufficiently strong sheared flow when approaching the shear Alfvén resonance (AR). In the nonlinear phase, a moderate (strong) sheared flow leads to a smaller (larger) saturated island width. The stabilization of tearing modes by moderate shear plasma flow is enhanced for a larger plasma viscosity and a lower Alfvén velocity. It is also found that in the nonlinear phase AR accelerates the plasma rotation around the 2/1 rational surface but decelerates it at the AR location, and the radial location satisfying AR spreads inwards towards the magnetic axis.
A novel crowd flow model based on linear fractional stable motion
NASA Astrophysics Data System (ADS)
Wei, Juan; Zhang, Hong; Wu, Zhenya; He, Junlin; Guo, Yangyong
2016-03-01
For the evacuation dynamics in indoor space, a novel crowd flow model is put forward based on Linear Fractional Stable Motion. Based on position attraction and queuing time, the calculation formula of movement probability is defined and the queuing time is depicted according to linear fractal stable movement. At last, an experiment and simulation platform can be used for performance analysis, studying deeply the relation among system evacuation time, crowd density and exit flow rate. It is concluded that the evacuation time and the exit flow rate have positive correlations with the crowd density, and when the exit width reaches to the threshold value, it will not effectively decrease the evacuation time by further increasing the exit width.
Wang, Chengduan; Chen, Wenmei; Li, Jianming; Jiang, Guangming
2002-07-01
A new type of polypropylene tubular membrane apparatus of rotating cross flow was designed to study experimentally the flow field characteristics of the tangential section of the membrane annular gap. The authors designed rotary linear tangential flow tubular membrane separator and its test system for the first time. Through the system, the flow field of rotary linear tangential flow with the advanced Particle Image Velocimetry (PIV) was tested for the first time. A lot of streamlines and vorticity maps of the tangential section of separator in different operation conditions were obtained. The velocity distribution characteristics were analyzed quantitatively: 1. At non-vortex area, no matter how the operation parameters change, the velocity near to rotary tangential flow entrance was higher than the velocity far from entrance at the same radial coordinates. At vortex area, generally the flow velocity of inner vortex was lower than the outer vortex. At the vortex center, the velocity was lowest, the tangential velocity were equal to zero generally. At the vortex center zone, the tangential velocity was less than the axial velocity. 2. Under test operations, the tangential velocity and axial velocity of vortices borders are 1-2 times of average axial velocity of membrane module annular gap. The maximum tangential velocity and axial velocity of ellipse vortices were 2-6 times of average axial velocity of membrane module annular gap. 3. The vortices that are formed on the tangential section, there existed mass transfer between inner and outer parts of fluid. Much fluid of outer vortices got into the inner ones, which was able to prevent membrane tube from particles blocking up very soon. PMID:12371104
Routine detection of Epstein-Barr virus specific T-cells in the peripheral blood by flow cytometry
NASA Technical Reports Server (NTRS)
Crucian, B. E.; Stowe, R. P.; Pierson, D. L.; Sams, C. F.
2001-01-01
The ability to detect cytomegalovirus-specific T-cells (CD4(+)) in the peripheral blood by flow cytometry has been recently described by Picker et al. In this method, cells are incubated with viral antigen and responding (cytokine producing) T-cells are then identified by flow cytometry. To date, this technique has not been reliably used to detect Epstein-Barr virus (EBV)-specific T-cells primarily due to the superantigen/mitogenic properties of the virus which non-specifically activate T-cells. By modifying culture conditions under which the antigens are presented, we have overcome this limitation and developed an assay to detect and quantitate EBV-specific T-cells. The detection of cytokine producing T-cells by flow cytometry requires an extremely strong signal (such as culture in the presence of PMA and ionomycin). Our data indicate that in modified culture conditions (early removal of viral antigen) the non-specific activation of T-cells by EBV is reduced, but antigen presentation will continue uninhibited. Using this method, EBV-specific T-cells may be legitimately detected using flow cytometry. No reduction in the numbers of antigen-specific T-cells was observed by the early removal of target antigen when verified using cytomegalovirus antigen (a virus with no non-specific T-cell activation properties). In EBV-seropositive individuals, the phenotype of the EBV-specific cytokine producing T-cells was evaluated using four-color flow cytometry and found to be CD45(+), CD3(+), CD4(+), CD45RA(-), CD69(+), CD25(-). This phenotype indicates the stimulation of circulating previously unactivated memory T-cells. No cytokine production was observed in CD4(+) T-cells from EBV-seronegative individuals, confirming the specificity of this assay. In addition, the use of four color cytometry (CD45, CD3, CD69, IFNgamma/IL-2) allows the total quantitative assessment of EBV-specific T-cells while monitoring the interference of EBV non-specific mitogenic activity. This method may
Linear model describing three components of flow in karst aquifers using 18O data
Long, A.J.; Putnam, L.D.
2004-01-01
The stable isotope of oxygen, 18O, is used as a naturally occurring ground-water tracer. Time-series data for ??18O are analyzed to model the distinct responses and relative proportions of the conduit, intermediate, and diffuse flow components in karst aquifers. This analysis also describes mathematically the dynamics of the transient fluid interchange between conduits and diffusive networks. Conduit and intermediate flow are described by linear-systems methods, whereas diffuse flow is described by mass-balance methods. An automated optimization process estimates parameters of lognormal, Pearson type III, and gamma distributions, which are used as transfer functions in linear-systems analysis. Diffuse flow and mixing parameters also are estimated by these optimization methods. Results indicate the relative proximity of a well to a main conduit flowpath and can help to predict the movement and residence times of potential contaminants. The three-component linear model is applied to five wells, which respond to changes in the isotopic composition of point recharge water from a sinking stream in the Madison aquifer in the Black Hills of South Dakota. Flow velocities as much as 540 m/d and system memories of as much as 71 years are estimated by this method. Also, the mean, median, and standard deviation of traveltimes; time to peak response; and the relative fraction of flow for each of the three components are determined for these wells. This analysis infers that flow may branch apart and rejoin as a result of an anastomotic (or channeled) karst network.
Linear instabilities and recurring bursts of turbulence in rotating channel flow simulations
NASA Astrophysics Data System (ADS)
Brethouwer, Geert
2016-09-01
Intense recurring bursts of turbulence on a long time scale are observed in direct numerical simulations (DNSs) of channel flow subject to rapid spanwise rotation for a range of Reynolds numbers and rotation speeds. A necessary condition for manifestation of cyclic turbulent bursts is that the Reynolds number and rotation speed are sufficiently high. The principal cause of turbulent bursts is a linearly unstable Tollmien-Schlichting-like wave with a wave vector normal to the rotation axis. This exponentially growing wave breaks down through a secondary instability when its amplitude is large causing a burst of turbulence. A new instability develops once turbulence has subsided leading to a continuous and self-sustained cycle of bursts. In several DNSs a recurring instability happens despite the flow being strongly and continuously turbulent in a part of the channel while in other DNSs turbulence is mostly weak between bursts. DNS observations have been compared to linear stability theory using the spatially averaged velocity of the DNS as base flow. Analysis shows that Tollmien-Schlichting waves are linearly unstable if Reynolds number and rotation speed are sufficiently high and bursts are observed. In several cases a good agreement between predicted and observed growth rate and eigenfunction of the instability is found, but in other cases the growth rate is overpredicted by linear stability theory and in some cases a Tollmien-Schlichting instability is predicted but not observed. Further study indicates that when observations and predictions differ turbulence or other modes alter the unstable wave, thereby reducing its ability to extract energy from the mean flow. In none of the analyzed DNSs was a significant nonlinear energy transfer from the unstable mode to other modes noted. Inclusion of an eddy viscosity in linear stability theory did not notably improve correspondence with DNSs.
Wejner-Mik, Paulina; Nouri, Aria; Szymczyk, Ewa; Krzemińska-Pakuła, Maria; Lipiec, Piotr
2013-01-01
Introduction We hypothesized that coronary flow reserve (CFR) in the left anterior descending artery (LAD) can be effectively measured during an accelerated dipyridamole-atropine stress echocardiography (DASE) protocol to improve the diagnostic performance of the test. Material and methods In 64 patients with suspected or known coronary artery disease scheduled for coronary angiography DASE with concomitant CFR measurement in LAD was performed. Results Coronary flow reserve measurement and calculation were feasible in 83% of patients. The positive predictive value of undetectable LAD flow was 81% for severe LAD disease. Measured values of CFR were in the range 1.3–4.1 (mean: 2.2 ±0.7). Significantly lower CFR was found in patients with LAD disease (1.97 ±0.62 vs. 2.55 ±0.57, p = 0.0015). The optimal cutoff for detecting ≥ 50% stenosis was CFR ≤ 2.1 (ROC AUC 0.776), corresponding with 68% sensitivity and 84% specificity. In patients with negative DASE results 67% of patients with LAD disease had abnormal CFR, whereas in patients with a positive DASE result 92% of patients with normal LAD had normal CFR. The DASE diagnostic accuracy for the detection of coronary artery disease (CAD) increased from 75% to 85% when CFR measurement was added to wall motion abnormality (WMA) analysis. No test with both abnormalities was false positive for the detection of coronary disease. Conclusions Incorporation of CFR measurement into WMA-based stress echocardiography is feasible even in an accelerated DASE protocol and can be translated into an approximate gain of 10% in overall test accuracy. PMID:24273560
Linear Modeling and Evaluation of Controls on Flow Response in Western Post-Fire Watersheds
NASA Astrophysics Data System (ADS)
Saxe, S.; Hogue, T. S.; Hay, L.
2015-12-01
This research investigates the impact of wildfires on watershed flow regimes throughout the western United States, specifically focusing on evaluation of fire events within specified subregions and determination of the impact of climate and geophysical variables in post-fire flow response. Fire events were collected through federal and state-level databases and streamflow data were collected from U.S. Geological Survey stream gages. 263 watersheds were identified with at least 10 years of continuous pre-fire daily streamflow records and 5 years of continuous post-fire daily flow records. For each watershed, percent changes in runoff ratio (RO), annual seven day low-flows (7Q2) and annual seven day high-flows (7Q10) were calculated from pre- to post-fire. Numerous independent variables were identified for each watershed and fire event, including topographic, land cover, climate, burn severity, and soils data. The national watersheds were divided into five regions through K-clustering and a lasso linear regression model, applying the Leave-One-Out calibration method, was calculated for each region. Nash-Sutcliffe Efficiency (NSE) was used to determine the accuracy of the resulting models. The regions encompassing the United States along and west of the Rocky Mountains, excluding the coastal watersheds, produced the most accurate linear models. The Pacific coast region models produced poor and inconsistent results, indicating that the regions need to be further subdivided. Presently, RO and HF response variables appear to be more easily modeled than LF. Results of linear regression modeling showed varying importance of watershed and fire event variables, with conflicting correlation between land cover types and soil types by region. The addition of further independent variables and constriction of current variables based on correlation indicators is ongoing and should allow for more accurate linear regression modeling.
Wave Driven Non-linear Flow Oscillator for the 22-Year Solar Cycle
NASA Technical Reports Server (NTRS)
Mayr, Hans G.; Wolff, Charles L.; Hartle, Richard E.; Einaudi, Franco (Technical Monitor)
2000-01-01
In the Earth's atmosphere, a zonal flow oscillation is observed with periods between 20 and 32 months, the Quasi Biennial Oscillation. This oscillation does not require external time dependent forcing but is maintained by non-linear wave momentum deposition. It is proposed that such a mechanism also drives long-period oscillations in planetary and stellar interiors. We apply this mechanism to generate a flow oscillation for the 22-year solar cycle. The oscillation would occur just below the convective envelope where waves can propagate. Using scale analysis, we present results from a simplified model that incorporates Hines' gravity wave parameterization. Wave amplitudes less than 10 m/s can produce reversing zonal flows of 25 m/s that should be sufficient to generate a corresponding oscillation in the poloidal magnetic field. Low buoyancy frequency and the associated increase in turbulence help to produce the desired oscillation period of the flow.
Prediction of Transonic Vortex Flows Using Linear and Nonlinear Turbulent Eddy Viscosity Models
NASA Technical Reports Server (NTRS)
Bartels, Robert E.; Gatski, Thomas B.
2000-01-01
Three-dimensional transonic flow over a delta wing is investigated with a focus on the effect of transition and influence of turbulence stress anisotropies. The performance of linear eddy viscosity models and an explicit algebraic stress model is assessed at the start of vortex flow, and the results compared with experimental data. To assess the effect of transition location, computations that either fix transition or are fully turbulent are performed. To assess the effect of the turbulent stress anisotropy, comparisons are made between predictions from the algebraic stress model and the linear eddy viscosity models. Both transition location and turbulent stress anisotropy significantly affect the 3D flow field. The most significant effect is found to be the modeling of transition location. At a Mach number of 0.90, the computed solution changes character from steady to unsteady depending on transition onset. Accounting for the anisotropies in the turbulent stresses also considerably impacts the flow, most notably in the outboard region of flow separation.
A free-trailing vane flow direction indicator employing a linear output Hall effect transducer
NASA Technical Reports Server (NTRS)
Zell, Peter T.; Mcmahon, Robert D.
1988-01-01
The Hall effect vane (HEV) was developed to measure flow angularity in the NASA 40-by-80-foot and 80-by-120-foot wind tunnels. This indicator is capable of sensing flow direction at air speeds from 5 to 300 knots and over a + or - 40 deg angle range with a resolution of 0.1 deg. A free-trailing vane configuration employing a linear output Hall effect transducer as a shaft angle resolver was used. The current configuration of the HEV is designed primarily for wind tunnel calibration testing; however, other potential applications include atmospheric, flight or ground research testing. The HEV met initial design requirements.
Linear stability analysis and direct numerical simulation of a miscible two-fluid channel flow
NASA Astrophysics Data System (ADS)
Haapanen, Siina Ilona
The temporal evolution of an initially laminar two-fluid channel flow is investigated using linear stability analysis and direct numerical simulation. The stability of a two-fluid shear flow is encountered in numerous situations, including water wave generation by wind, atomization of fuels, aircraft deicing and nuclear reactor cooling. The application of particular interest in this study is liquefying hybrid combustion, for which the two-fluid channel flow is used as a model problem to characterize the relevant mixing and entrainment mechanisms. The two fluids are miscible with dissimilar densities and viscosities. The thickness of one of the fluid layers is much smaller than that of the other, with the denser and more viscous fluid comprising the thin layer. Linear stability analysis is used to identify possibly unstable modes in the two-fluid configuration. The analysis is considered for two different situations. In one case, the fluid density and viscosity change discontinuously across a sharp interface, while in the other, the fluids are separated by a finite thickness transition layer, over which the fluid properties vary continuously. In the sharp interface limit, the linear stability is governed by an Orr-Sommerfeld equation in each fluid layer, coupled by boundary conditions at the interface. A numerical solution of the system of equations is performed using a Chebyshev spectral collocation method. In the case where the fluids are separated by a finite thickness transition zone, an Orr-Sommerfeld-type equation is solved with the compound matrix method. The non-linear stages of the flow evolution are investigated by direct numerical simulation. In a temporal simulation, two of the three spatial dimensions are periodic. Fourier spectral discretization is used in these dimensions, while a compact finite difference scheme is utilized in the non-periodic direction. The time advancement is performed by a projection method with a third order Adams
Linear and weakly nonlinear global instability of a fluid flow through a collapsible channel
NASA Astrophysics Data System (ADS)
Amaouche, Mustapha; Di Labbio, Giuseppe
2016-04-01
Interactions between an internal flow and wall deformation occur in many biological systems. Such interactions can involve a complex and rich dynamical behavior and a number of peculiarities which depend on the flow parameter range. The aim of this paper is to present a variant (obtained via a weighted residual approach) of the averaged one-dimensional model derived by Stewart et al. ["Local and global instabilities of flow in a flexible-walled channel," Eur. J. Mech. B/Fluids 28, 541-557 (2009)]. The asymptotic expansions for small Reynolds numbers of these two models, compared to the exact solution obtained from the lubrication approach, reveal some quantitative difference, even at higher Reynolds numbers. Qualitatively, the two models give similar results at least at a linear level. It is shown that for relatively low membrane tension (T), there are distinct regions in the (T, R) parameter space where steady bifurcating flows may occur. These flows can also be observed at vanishingly small Reynolds numbers combined with relatively high membrane tension. At sufficiently high T and R, the bifurcating flow is rather time periodic. A weakly nonlinear analysis is then performed in both cases leading to the derivation of evolution equations for the amplitudes of the bifurcating flows. The amplitude equations show that the saddle node bifurcation has a transcritical character while the Hopf bifurcation is either subcritical or supercritical, depending both on the mode number and membrane tension.
Linear and nonlinear instability in vertical counter-current laminar gas-liquid flows
NASA Astrophysics Data System (ADS)
Schmidt, Patrick; Ó Náraigh, Lennon; Lucquiaud, Mathieu; Valluri, Prashant
2016-04-01
We consider the genesis and dynamics of interfacial instability in vertical gas-liquid flows, using as a model the two-dimensional channel flow of a thin falling film sheared by counter-current gas. The methodology is linear stability theory (Orr-Sommerfeld analysis) together with direct numerical simulation of the two-phase flow in the case of nonlinear disturbances. We investigate the influence of two main flow parameters on the interfacial dynamics, namely the film thickness and pressure drop applied to drive the gas stream. To make contact with existing studies in the literature, the effect of various density contrasts is also examined. Energy budget analyses based on the Orr-Sommerfeld theory reveal various coexisting unstable modes (interfacial, shear, internal) in the case of high density contrasts, which results in mode coalescence and mode competition, but only one dynamically relevant unstable interfacial mode for low density contrast. A study of absolute and convective instability for low density contrast shows that the system is absolutely unstable for all but two narrow regions of the investigated parameter space. Direct numerical simulations of the same system (low density contrast) show that linear theory holds up remarkably well upon the onset of large-amplitude waves as well as the existence of weakly nonlinear waves. For high density contrasts, corresponding more closely to an air-water-type system, linear stability theory is also successful at determining the most-dominant features in the interfacial wave dynamics at early-to-intermediate times. Nevertheless, the short waves selected by the linear theory undergo secondary instability and the wave train is no longer regular but rather exhibits chaotic motion. The same linear stability theory predicts when the direction of travel of the waves changes — from downwards to upwards. We outline the practical implications of this change in terms of loading and flooding. The change in direction of the
Linear drag law for high-Reynolds-number flow past an oscillating body
NASA Astrophysics Data System (ADS)
Agre, Natalie; Childress, Stephen; Zhang, Jun; Ristroph, Leif
2016-07-01
An object immersed in a fast flow typically experiences fluid forces that increase with the square of speed. Here we explore how this high-Reynolds-number force-speed relationship is affected by unsteady motions of a body. Experiments on disks that are driven to oscillate while progressing through air reveal two distinct regimes: a conventional quadratic relationship for slow oscillations and an anomalous scaling for fast flapping in which the time-averaged drag increases linearly with flow speed. In the linear regime, flow visualization shows that a pair of counterrotating vortices is shed with each oscillation and a model that views a train of such dipoles as a momentum jet reproduces the linearity. We also show that appropriate scaling variables collapse the experimental data from both regimes and for different oscillatory motions into a single drag-speed relationship. These results could provide insight into the aerodynamic resistance incurred by oscillating wings in flight and they suggest that vibrations can be an effective means to actively control the drag on an object.
Linear stability of spiral and annular Poiseuille flow for small radius ratio
NASA Astrophysics Data System (ADS)
Cotrell, David L.; Pearlstein, Arne J.
For the radius ratio η ≡ R_i/R_o = 0.1 and several rotation rate ratios μ ≡ Ω_o/Ω_i, we consider the linear stability of spiral Poiseuille flow (SPF) up to Re = 10^5, where R_i and R_o are the radii of the inner and outer cylinders, respectively, Re ≡ overline V_Z(R_o -R_i)/ν is the Reynolds number, Ω_i and Ω_o are the (signed) angular speeds of the inner and outer cylinders, respectively, ν is the kinematic viscosity, and overline V_Z is the mean axial velocity. The Re range extends more than three orders of magnitude beyond that considered in the previous μ = 0 work of Recktenwald et al. (Phys. Rev. E, vol. 48, 1993, p. 444). We show that in the non-rotating limit of annular Poiseuille flow, linear instability does not occur below a critical radius ratio hat η ≈ 0.115. We also establish the connection of the linear stability of annular Poiseuille flow for 0 < η ≤ hat η at all Re to the linear stability of circular Poiseuille flow (η = 0) at all Re. For the rotating case, with μ = -1, - 0.5, - 0.25, 0 and 0.2, the stability boundaries, presented in terms of critical Taylor number Ta ≡ Ω_i(R_o -R_i)^2/ν versus Re, show that the results are qualitatively different from those at larger η. For each μ, the centrifugal instability at small Re does not connect to a high-Re Tollmien Schlichting-like instability of annular Poiseuille flow, since the latter instability does not exist for η < hatη. We find a range of Re for which disconnected neutral curves exist in the k Ta plane, which for each non-zero μ considered, lead to a multi-valued stability boundary, corresponding to two disjoint ranges of stable Ta. For each counter-rotating (μ < 0) case, there is a finite range of Re for which there exist three critical values of Ta, with the upper branch emanating from the Re = 0 instability of Couette flow. For the co-rotating (μ = 0.2) case, there are two critical values of Ta for each Re in an apparently semi-infinite range of Re, with
Linear stability of the Couette flow of a vibrationally excited gas. 2. viscous problem
NASA Astrophysics Data System (ADS)
Grigor'ev, Yu. N.; Ershov, I. V.
2016-03-01
Based on the linear theory, stability of viscous disturbances in a supersonic plane Couette flow of a vibrationally excited gas described by a system of linearized equations of two-temperature gas dynamics including shear and bulk viscosity is studied. It is demonstrated that two sets are identified in the spectrum of the problem of stability of plane waves, similar to the case of a perfect gas. One set consists of viscous acoustic modes, which asymptotically converge to even and odd inviscid acoustic modes at high Reynolds numbers. The eigenvalues from the other set have no asymptotic relationship with the inviscid problem and are characterized by large damping decrements. Two most unstable viscous acoustic modes (I and II) are identified; the limits of these modes were considered previously in the inviscid approximation. It is shown that there are domains in the space of parameters for both modes, where the presence of viscosity induces appreciable destabilization of the flow. Moreover, the growth rates of disturbances are appreciably greater than the corresponding values for the inviscid flow, while thermal excitation in the entire considered range of parameters increases the stability of the viscous flow. For a vibrationally excited gas, the critical Reynolds number as a function of the thermal nonequilibrium degree is found to be greater by 12% than for a perfect gas.
Linear stability of plane Poiseuille flow in an infinite elastic medium and volcanic tremors
NASA Astrophysics Data System (ADS)
Sakuraba, Ataru; Yamauchi, Hatsuki
2014-12-01
The linear stability of a plane compressible laminar (Poiseuille) flow sandwiched between two semi-infinite elastic media was investigated with the aim of explaining the excitation of volcanic tremors. Our results show that there are several regimes of instability, and the nature of stability significantly depends on the symmetry of oscillatory fluid and solid motion. It has been shown that long-wave symmetric instability occurs at a very small value of the Reynolds number, but it is unlikely that this is the cause of volcanic tremors. We show that antisymmetric (flexural) instability also occurs, involving two parallel Rayleigh waves traveling against the Poiseuille flow, but the critical flow speed is faster than that of symmetric instability. However, if the basic flow profile is nonparabolic because of a nonuniform driving force or nonuniform viscosity, the critical flow speed of antisymmetric instability can be considerably slower than that of symmetric instability. Based on numerical calculations and analytical consideration, we conclude that this anomalous antisymmetric instability is possibly produced by a basaltic magma flow of a few meters per second through a dike with thickness of 1 m and extending for several kilometers; this origin can explain some of the characteristics of volcanic tremors.
Linearity of pulsatile pressure-flow relations in the embryonic chick vascular system.
Yoshigi, M; Keller, B B
1996-10-01
The calculation and modeling of vascular input impedance are based on the assumption that pressure and flow are linearly related in the frequency domain. However, this assumption has not been proven for the embryonic circulation. Therefore, we investigated the linearity of pulsatile pressure flow relations in vivo with acute alterations in cycle length. We simultaneously measured dorsal aortic pressure with a servonull system and flow velocity with a 20-MHz pulsed-Doppler system in stage 24 chick embryos (n = 38). Cycle length was acutely altered using thermal probe(s) applied to the sinus venosus. We determined the impedance spectra at several cycle lengths for each embryo and a reference curve from a three-element Windkessel model with the use of nonlinear curve fitting. We then assessed the scatter of experimental impedance along the reference curve as a measure of linearity in the frequency domain. We found that mean vascular resistance did not change after thermal probe applications (P > .20 for each), indicating that acute alterations in cycle length did not alter peripheral vascular properties. Superpositioned impedance spectra showed minimal scatter along the model impedance from 0 to 6 Hz. Goodness of fit values (R2) were near unity (.94 to .97) and were similar for all interventions (P > .07 for Fisher's z, by F test). Above 6 Hz, both modulus and phase spectra exhibited significant scatter (P < .05, by F test). Experimental impedance spectra tended to have a fluctuation and a phase-zero crossover, indicating significant wave reflection in the embryonic circulation. Thus, the embryonic vascular system can be approximated as a linear system from 0 to 6 Hz, the range in which the majority (96.0 +/- 0.18%) of hydraulic energy is dissipated.
Unsteady flows in a two-dimensional linear cascade with low-pressure turbine blades
NASA Astrophysics Data System (ADS)
Murawski, Christopher Gabriel
Experimental studies of unsteady flow phenomena in a low pressure turbine linear cascade are presented. Turbine engine flow passages contain numerous loss mechanisms. The loss mechanisms investigated in this study are low Reynolds number and freestream turbulence effects, secondary flows and wake interactions. Also, a method is implemented which decreases the profile losses due to low Reynolds number effects. The results are presented in three segments. First, the effects of Reynolds number and freestream turbulence intensity on the low-pressure turbine cascade blade are investigated. The condition of the blade's boundary layer is the leading factor controlling the level of profile loss. The losses from the airfoil decrease as the Reynolds number and freestream turbulence increase due to a decrease in the size of the separation zone on the suction side of the turbine airfoil. Boundary layer separation occurs on the suction surface of the turbine. Changes to this region are achieved when attaching different length tail sets to the turbine airfoils which alters the axial chord of each blade. A clear improvement on suction side boundary layer behavior at low Reynolds numbers was seen when the tail extensions were shorter than about 9% of axial chord. Finally, the effect wake disturbance frequency on the secondary flow vortex structure in a turbine cascade is studied. Cylinders are traversed across the front of the blade row to simulate turbine blade disturbances. The response of the secondary flow structure to the movement of the wake generator shuttle with zero, one and multiple wake generator rods are presented. Multiple wake disturbance frequencies are varied from 12 Hz to 52 Hz. Multiple wake disturbance frequency below the axial chord flow frequency enable the secondary flow vortex structure to re-establish itself between each wake disturbance event. Axial chord flow frequency is defined as the axial velocity in the cascade divided by the axial chord length of
Linear Stability of Plane Poiseuille Flow in an Infinite Elastic Medium and Volcanic Tremors
NASA Astrophysics Data System (ADS)
Sakuraba, A.; Yamauchi, H.
2013-12-01
The linear stability of a plane compressible laminar (Poiseuille) flow sandwiched between two semi-infinite elastically deformable media was investigated with the aim of presenting a general explanation for the excitation of volcanic tremors, which are characterized as long-period and long-lasting seismic events uniquely observed at active volcanoes. Results show that there are several regimes of instability and these primarily depend on the symmetry of the oscillatory fluid and solid motion, wavelength, and fluid viscosity. It is found that the antisymmetric (flexural) instability, involving two parallel Rayleigh waves traveling against the Poiseuille flow, occurs at a critical flow speed much slower than that of symmetric instability. Symmetric instability involves a slow Krauklis (crack) wave traveling with the Poiseuille flow, and it is unlikely that this is the cause of volcanic tremors. The critical flow speed for the antisymmetric instability decreases inversely proportional to the wavelength, and the asymptotic solution is derived when the wavelength is very long. The physical mechanism of this instability can be understood as a simple friction drag on the Rayleigh-wave particle motion caused by the main Poiseuille flow. Based on numerical calculations and analytical consideration, we conclude that the antisymmetric instability is possibly produced by a basaltic magma flow of 1 m/s through a dike of thickness 1 m and extending for several kilometers; this origin can explain some of the characteristics of volcanic tremors. A schematic explanation for the antisymmetric instability. A solid particle (open circle) at the boundary moves along an ellipse (dotted line). White arrows represent the perturbed fluid and solid velocities. The plane Poiseuille flow is represented by black arrows with its parabolic envelop.
The use of linearized-aerodynamics and vortex-flow methods in aircraft design /invited paper/
NASA Technical Reports Server (NTRS)
Lamar, J. E.
1982-01-01
This paper deals with selected linearized-aerodynamic and vortex-flow methods as applied to aircraft design problems at high subsonic speeds. In particular, the NASA Vortex Lattice and Modified Multhopp methods are the linearized techniques employed, and the suction analogy is used to provide estimates associated with vortex-flow aerodynamics. Many examples are given as to how researchers at Langley have used these methods to design the high subsonic, wing-mean-camber shapes for various configurations such as a supersonic transport, high-aspect-ratio transport, trapezoidal fighter wing, strake wing, tandem wing, joined wing, delta wing, and slender cranked wing. Many of these have been built, tested, and have had their data compared with theory. In addition, a technique for defining efficiently performing strake planforms for use in strake-wing combinations is discussed, and further improvements in wing design are outlined. The latter may be obtained by using higher-ordered linear panel methods as well as nonlinear-transonic methods.
Non-linear flow transients in fractured rock masses - the 1995 injection experiment in Soultz
Kohl, T.; Jung, R.; Hopkirk, R.J.; Rybach, L.
1996-01-24
In July 1995 in the course of the Hot Dry Rock (HDR) site investigation studies in Soultz s.F. (France) multi rate hydraulic injection tests were conducted in the borehole GPK2. The downhole pressure records obtained from the lowermost depth domain between 3211 m and 3876 m demonstrate non-laminar hydraulic behavior. Such behavior was also observed earlier during a similar set of flow step tests in the GPKl borehole Soultz. Like the analysis of these earlier data sets, it could be shown that the pressure records from July 1995 are corresponding to empirical flow laws established for non-laminar hydraulic regimes. In this study a numerical model is described which is being developed for the analysis of non-laminar flow in fractures. Similar models have already been applied to production and injection tests at GPK1. The results show that the observed transient pressure record is well predicted by such a non-linear flow law. Conventional laminar flow models cannot reproduce these curves. An evaluation of the parameters resulting from both, steady state and transient analysis leads to assumptions on the geometry of the main fracture system. Our calculations show that surface areas above 0.05 km² and apertures in the order of 0.4 mm results in an excellent fit of the data.
On three-dimensional linear stability of Poiseuille flow of Bingham fluids
NASA Astrophysics Data System (ADS)
Frigaard, Ian; Nouar, Cherif
2003-10-01
Plane channel Poiseuille flow of a Bingham fluid is characterized by the Bingham number, B, which describes the ratio of yield and viscous stresses. Unlike purely viscous non-Newtonian fluids, which modify hydrodynamic stability studies only through the dissipation and the basic flow, inclusion of a yield stress additionally results in a modified domain and boundary conditions for the stability problem. We investigate the effects of increasing B on the stability of the flow, using eigenvalue bounds that incorporate these features. As B→∞ we show that three-dimensional linear stability can be achieved for a Reynolds number bound of form Re=O(B3/4), for all wavelengths. For long wavelengths this can be improved to Re=O(B), which compares well with computed linear stability results for two-dimensional disturbances [J. Fluid Mech. 263, 133 (1994)]. It is also possible to find bounds of form Re=O(B1/2), which derive from purely viscous dissipation acting over the reduced domain and are comparable with the nonlinear stability bounds in J. Non-Newt. Fluid Mech. 100, 127 (2001). We also show that a Squire-like result can be derived for the plane channel flow. Namely, if the equivalent eigenvalue bounds for a Newtonian fluid yield a stability criterion, then the same stability criterion is valid for the Bingham fluid flow, but with reduced wavenumbers and Reynolds numbers. An application of these results is to bound the regions of parameter space in which computational methods need to be used.
Linear analysis on the growth of non-spherical perturbations in supersonic accretion flows
Takahashi, Kazuya; Yamada, Shoichi
2014-10-20
We analyzed the growth of non-spherical perturbations in supersonic accretion flows. We have in mind an application to the post-bounce phase of core-collapse supernovae (CCSNe). Such non-spherical perturbations have been suggested by a series of papers by Arnett, who has numerically investigated violent convections in the outer layers of pre-collapse stars. Moreover, Couch and Ott demonstrated in their numerical simulations that such perturbations may lead to a successful supernova even for a progenitor that fails to explode without fluctuations. This study investigated the linear growth of perturbations during the infall onto a stalled shock wave. The linearized equations are solved as an initial and boundary value problem with the use of a Laplace transform. The background is a Bondi accretion flow whose parameters are chosen to mimic the 15 M {sub ☉} progenitor model by Woosley and Heger, which is supposed to be a typical progenitor of CCSNe. We found that the perturbations that are given at a large radius grow as they flow down to the shock radius; the density perturbations can be amplified by a factor of 30, for example. We analytically show that the growth rate is proportional to l, the index of the spherical harmonics. We also found that the perturbations oscillate in time with frequencies that are similar to those of the standing accretion shock instability. This may have an implication for shock revival in CCSNe, which will be investigated in our forthcoming paper in more detail.
Dynamic modeling of mass-flowing linear medium with large amplitude displacement and rotation
NASA Astrophysics Data System (ADS)
Hong, Difeng; Tang, Jiali; Ren, Gexue
2011-11-01
In this paper, a dynamic model of a linear medium with mass flow, such as traveling strings, cables, belts, beams or pipes conveying fluids, is proposed, in the framework of Arbitrary-Lagrange-Euler (ALE) description. The material coordinate is introduced to characterize the mass-flow of the medium, and the Absolute Nodal Coordinate Formulation (ANCF) is employed to capture geometric nonlinearity of the linear media under large displacement and rotation. The governing equations are derived in terms of d'Alembert's principle. When using an ALE description, complex mass-flowing boundary conditions can be easily enforced. Numerical examples are presented to validate the proposed method by comparison with analytical results of simplified models. The computed critical fluid velocity for the stability of a cantilevered pipe conveying fluid is correlated with the available theory in literature. The large amplitude limit-cycle oscillations of flexible pipes conveying fluid are presented, and the effect of the velocity of the fluid on the static equilibrium of the pipe under gravity is investigated.
Lorber, A.A.; Carey, G.F.; Bova, S.W.; Harle, C.H.
1996-12-31
The connection between the solution of linear systems of equations by iterative methods and explicit time stepping techniques is used to accelerate to steady state the solution of ODE systems arising from discretized PDEs which may involve either physical or artificial transient terms. Specifically, a class of Runge-Kutta (RK) time integration schemes with extended stability domains has been used to develop recursion formulas which lead to accelerated iterative performance. The coefficients for the RK schemes are chosen based on the theory of Chebyshev iteration polynomials in conjunction with a local linear stability analysis. We refer to these schemes as Chebyshev Parameterized Runge Kutta (CPRK) methods. CPRK methods of one to four stages are derived as functions of the parameters which describe an ellipse {Epsilon} which the stability domain of the methods is known to contain. Of particular interest are two-stage, first-order CPRK and four-stage, first-order methods. It is found that the former method can be identified with any two-stage RK method through the correct choice of parameters. The latter method is found to have a wide range of stability domains, with a maximum extension of 32 along the real axis. Recursion performance results are presented below for a model linear convection-diffusion problem as well as non-linear fluid flow problems discretized by both finite-difference and finite-element methods.
Asymptotic Behavior of Ensemble-Averaged Linear Disturbances in Homogeneous Shear Flow
NASA Technical Reports Server (NTRS)
Thacker, W. D.; Grosch, C E.; Gatski, T. B.
1999-01-01
In order to expand the predictive capability of single-point turbulence closure models too account for the early-stage transition regime, a methodology for the formulation and calibration of model equations for the ensemble-averaged disturbance kinetic energy and energy dissipation rate is presented. The calibration is based on homogeneous shear flow where disturbances can be described by rapid distort,ion theory (RDT). The relationship between RDT and linear stability theory is exploit,c d in order to obtain a closed set, of modeled equations. The linear disturbance equations are solved directly so that, the numerical simulation yields a database from which the closure coefficient,s in the ensemble-averaged disturbance equations can he determined.
Eck, H. J. N. van; Koppers, W. R.; Rooij, G. J. van; Goedheer, W. J.; Cardozo, N. J. Lopes; Kleyn, A. W.; Engeln, R.; Schram, D. C.
2009-03-15
The direct simulation Monte Carlo (DSMC) method was used to investigate the efficiency of differential pumping in linear plasma generators operating at high gas flows. Skimmers are used to separate the neutrals from the plasma beam, which is guided from the source to the target by a strong axial magnetic field. In this way, the neutrals are prevented to reach the target region. The neutral flux to the target must be lower than the plasma flux to enable ITER relevant plasma-surface interaction (PSI) studies. It is therefore essential to control the neutral gas dynamics. The DSMC method was used to model the expansion of a hot gas in a low pressure vessel where a small discrepancy in shock position was found between the simulations and a well-established empirical formula. Two stage differential pumping was modeled and applied in the linear plasma devices Pilot-PSI and PLEXIS. In Pilot-PSI a factor of 4.5 pressure reduction for H{sub 2} has been demonstrated. Both simulations and experiments showed that the optimum skimmer position depends on the position of the shock and therefore shifts for different gas parameters. The shape of the skimmer has to be designed such that it has a minimum impact on the shock structure. A too large angle between the skimmer and the forward direction of the gas flow leads to an influence on the expansion structure. A pressure increase in front of the skimmer is formed and the flow of the plasma beam becomes obstructed. It has been shown that a skimmer with an angle around 53 deg. gives the best performance. The use of skimmers is implemented in the design of the large linear plasma generator Magnum-PSI. Here, a three stage differentially pumped vacuum system is used to reach low enough neutral pressures near the target, opening a door to PSI research in the ITER relevant regime.
A parametric study of supersonic laminar flow for swept wings using linear stability analysis
NASA Technical Reports Server (NTRS)
Cummings, Russell M.; Garcia, Joseph A.; Tu, Eugene L.
1995-01-01
A parametric study to predict the extent of laminar flow on the upper surface of a generic swept-back wing (NACA 64A010 airfoil section) at supersonic speeds was conducted. The results were obtained by using surface pressure predictions from an Euler/Navier-Stokes computational fluid dynamics code coupled with a boundary layer code, which predicts detailed boundary layer profiles, and finally with a linear stability code to determine the extent of laminar flow. The parameters addressed are Reynolds number, angle of attack, and leading-edge wing sweep. The results of this study show that an increase in angle of attack, for specific Reynolds numbers, can actually delay transition. Therefore, higher lift capability, caused by the increased angle of attack, as well as a reduction in viscous drag due to the delay in transition is possible for certain flight conditions.
Linearized lattice Boltzmann method for micro- and nanoscale flow and heat transfer.
Shi, Yong; Yap, Ying Wan; Sader, John E
2015-07-01
Ability to characterize the heat transfer in flowing gases is important for a wide range of applications involving micro- and nanoscale devices. Gas flows away from the continuum limit can be captured using the Boltzmann equation, whose analytical solution poses a formidable challenge. An efficient and accurate numerical simulation of the Boltzmann equation is thus highly desirable. In this article, the linearized Boltzmann Bhatnagar-Gross-Krook equation is used to develop a hierarchy of thermal lattice Boltzmann (LB) models based on half-space Gaussian-Hermite (GH) quadrature ranging from low to high algebraic precision, using double distribution functions. Simplified versions of the LB models in the continuum limit are also derived, and are shown to be consistent with existing thermal LB models for noncontinuum heat transfer reported in the literature. Accuracy of the proposed LB hierarchy is assessed by simulating thermal Couette flows for a wide range of Knudsen numbers. Effects of the underlying quadrature schemes (half-space GH vs full-space GH) and continuum-limit simplifications on computational accuracy are also elaborated. The numerical findings in this article provide direct evidence of improved computational capability of the proposed LB models for modeling noncontinuum flows and heat transfer at small length scales.
Linearized lattice Boltzmann method for micro- and nanoscale flow and heat transfer.
Shi, Yong; Yap, Ying Wan; Sader, John E
2015-07-01
Ability to characterize the heat transfer in flowing gases is important for a wide range of applications involving micro- and nanoscale devices. Gas flows away from the continuum limit can be captured using the Boltzmann equation, whose analytical solution poses a formidable challenge. An efficient and accurate numerical simulation of the Boltzmann equation is thus highly desirable. In this article, the linearized Boltzmann Bhatnagar-Gross-Krook equation is used to develop a hierarchy of thermal lattice Boltzmann (LB) models based on half-space Gaussian-Hermite (GH) quadrature ranging from low to high algebraic precision, using double distribution functions. Simplified versions of the LB models in the continuum limit are also derived, and are shown to be consistent with existing thermal LB models for noncontinuum heat transfer reported in the literature. Accuracy of the proposed LB hierarchy is assessed by simulating thermal Couette flows for a wide range of Knudsen numbers. Effects of the underlying quadrature schemes (half-space GH vs full-space GH) and continuum-limit simplifications on computational accuracy are also elaborated. The numerical findings in this article provide direct evidence of improved computational capability of the proposed LB models for modeling noncontinuum flows and heat transfer at small length scales. PMID:26274307
Linearized lattice Boltzmann method for micro- and nanoscale flow and heat transfer
NASA Astrophysics Data System (ADS)
Shi, Yong; Yap, Ying Wan; Sader, John E.
2015-07-01
Ability to characterize the heat transfer in flowing gases is important for a wide range of applications involving micro- and nanoscale devices. Gas flows away from the continuum limit can be captured using the Boltzmann equation, whose analytical solution poses a formidable challenge. An efficient and accurate numerical simulation of the Boltzmann equation is thus highly desirable. In this article, the linearized Boltzmann Bhatnagar-Gross-Krook equation is used to develop a hierarchy of thermal lattice Boltzmann (LB) models based on half-space Gaussian-Hermite (GH) quadrature ranging from low to high algebraic precision, using double distribution functions. Simplified versions of the LB models in the continuum limit are also derived, and are shown to be consistent with existing thermal LB models for noncontinuum heat transfer reported in the literature. Accuracy of the proposed LB hierarchy is assessed by simulating thermal Couette flows for a wide range of Knudsen numbers. Effects of the underlying quadrature schemes (half-space GH vs full-space GH) and continuum-limit simplifications on computational accuracy are also elaborated. The numerical findings in this article provide direct evidence of improved computational capability of the proposed LB models for modeling noncontinuum flows and heat transfer at small length scales.
NASA Astrophysics Data System (ADS)
Gerik, A.; Kruhl, J. H.; Caggianelli, A.
2009-04-01
Magmatic processes such as magma emplacement and deformation-cooling histories leave visible traces in fabrics of magmatic rocks on all scales from µm to m. Together with the mostly diffuse and irregular nature of the patterns, this large scale range greatly impedes comprehensive analyses of the rock's fabrics. While such fabric patterns have been analyzed using a number of conventional methods over the last two decades, the resulting interpretations are mostly related to geometric aspects of the analyzed patterns on a specific scale. Fractal geometry-based quantification approaches can help overcome this problem, as they can be applied on larger scale ranges and thereby help extracting additional information. Furthermore, they are specifically suitable to analyze the pattern's complexity as well as anisotropies and inhomogeneities that may occur within a pattern. One issue that has prevented a widespread application of these methods is the fact that - compared to methods that are based on conventional statistical approaches - the time and effort required for the deployment of fractal geometry-based quantification approaches is much higher. However, the better availability of computing power and the development of automated routines along with their successful application on complex magmatic patterns has largely resolved such reservations. Still, the foundation of a meaningful analysis is laid in the initial preparation and processing of the analyzed patterns. To help avoid the influence of subjective decisions made along the way, we show an exemplary, rule-based work flow from pattern acquisition and image processing to deployment of automated quantification routines on a series of samples from geologically different locations within the Squillace Tonalite in the Serre (Calabria, Italy). All of the samples show evidence of flow, mingling and mixing processes of different intensity. These processes occurred during the injection and the shearing of the
Jin, Seung-Hyun; Lin, Peter; Hallett, Mark
2010-01-01
Objective To propose a model-free method to show linear and nonlinear information flow based on time delayed mutual information (TDMI) by employing uni- and bi-variate surrogate tests and to investigate whether there are contributions of the nonlinear information flow in corticomuscular (CM) interaction. Methods Using simulated data, we tested whether our method would successfully detect the direction of information flow and identify a relationship between two simulated time series. As an experimental data application, we applied this method to investigate CM interaction during a right wrist extension task. Results Results of simulation tests show that we can correctly detect the direction of information flow and the relationship between two time series without a prior knowledge of the dynamics of their generating systems. As experimental results, we found both linear and nonlinear information flow from contralateral sensorimotor cortex to muscle. Conclusions Our method is a viable model-free measure of temporally varying causal interactions that is capable of distinguishing linear and nonlinear information flow. With respect to experimental application, there are both linear and nonlinear information flows in CM interaction from contralateral sensorimotor cortex to muscle, which may reflect the motor command from brain to muscle. Significance This is the first study to show separate linear and nonlinear information flow in CM interaction. PMID:20044309
Warid, Warid; Hizam, Hashim; Mariun, Norman; Abdul-Wahab, Noor Izzri
2016-01-01
This paper proposes a new formulation for the multi-objective optimal power flow (MOOPF) problem for meshed power networks considering distributed generation. An efficacious multi-objective fuzzy linear programming optimization (MFLP) algorithm is proposed to solve the aforementioned problem with and without considering the distributed generation (DG) effect. A variant combination of objectives is considered for simultaneous optimization, including power loss, voltage stability, and shunt capacitors MVAR reserve. Fuzzy membership functions for these objectives are designed with extreme targets, whereas the inequality constraints are treated as hard constraints. The multi-objective fuzzy optimal power flow (OPF) formulation was converted into a crisp OPF in a successive linear programming (SLP) framework and solved using an efficient interior point method (IPM). To test the efficacy of the proposed approach, simulations are performed on the IEEE 30-busand IEEE 118-bus test systems. The MFLP optimization is solved for several optimization cases. The obtained results are compared with those presented in the literature. A unique solution with a high satisfaction for the assigned targets is gained. Results demonstrate the effectiveness of the proposed MFLP technique in terms of solution optimality and rapid convergence. Moreover, the results indicate that using the optimal DG location with the MFLP algorithm provides the solution with the highest quality. PMID:26954783
Warid, Warid; Hizam, Hashim; Mariun, Norman; Abdul-Wahab, Noor Izzri
2016-01-01
This paper proposes a new formulation for the multi-objective optimal power flow (MOOPF) problem for meshed power networks considering distributed generation. An efficacious multi-objective fuzzy linear programming optimization (MFLP) algorithm is proposed to solve the aforementioned problem with and without considering the distributed generation (DG) effect. A variant combination of objectives is considered for simultaneous optimization, including power loss, voltage stability, and shunt capacitors MVAR reserve. Fuzzy membership functions for these objectives are designed with extreme targets, whereas the inequality constraints are treated as hard constraints. The multi-objective fuzzy optimal power flow (OPF) formulation was converted into a crisp OPF in a successive linear programming (SLP) framework and solved using an efficient interior point method (IPM). To test the efficacy of the proposed approach, simulations are performed on the IEEE 30-busand IEEE 118-bus test systems. The MFLP optimization is solved for several optimization cases. The obtained results are compared with those presented in the literature. A unique solution with a high satisfaction for the assigned targets is gained. Results demonstrate the effectiveness of the proposed MFLP technique in terms of solution optimality and rapid convergence. Moreover, the results indicate that using the optimal DG location with the MFLP algorithm provides the solution with the highest quality. PMID:26954783
NASA Astrophysics Data System (ADS)
Qiao, Jundong; Delavan, Sarah
2014-11-01
Laboratory experiments were conducted to explore the mean flow structure and turbulence properties downstream of a spanwise suspended linear canopy in a 2-D open channel flow using the Particle Tracking Velocimetry technique. This canopy simulated the effect of one long-line structure of a mussel farm. Four experimental scenarios with the approach velocities 50, 80, 110, and 140 mm s-1 were under investigation. Three sub-layers formed downstream of the canopy. An internal canopy layer, where the time-averaged velocity decreases linearly with increasing distance downstream, a canopy mixing layer increasing in vertical extent with increasing distance downstream of the canopy, and an external canopy layer with higher velocity under the canopy, which may bring nutrients from the local ambient environment into this layer. The canopy turbulence results in upward momentum transport downstream of the canopy within a distance of 0.60 of the canopy depth and downward momentum transport beyond 1.20 of it. In the scenarios with relatively lower approach velocities 50 and 80 mm s1 , the wake turbulence results in upward momentum transport. The broader goal of this study is to offer guidelines for the design and site selection of more productive mussel farms. The results suggest that distance interval between the parallel long-lines in a mussel farm should be less than 0.6 times the height of a long-line dropper. Also, potential farm locations that are characterized with current velocity from 50 to 80 mm s1 are suggested.
Warid, Warid; Hizam, Hashim; Mariun, Norman; Abdul-Wahab, Noor Izzri
2016-01-01
This paper proposes a new formulation for the multi-objective optimal power flow (MOOPF) problem for meshed power networks considering distributed generation. An efficacious multi-objective fuzzy linear programming optimization (MFLP) algorithm is proposed to solve the aforementioned problem with and without considering the distributed generation (DG) effect. A variant combination of objectives is considered for simultaneous optimization, including power loss, voltage stability, and shunt capacitors MVAR reserve. Fuzzy membership functions for these objectives are designed with extreme targets, whereas the inequality constraints are treated as hard constraints. The multi-objective fuzzy optimal power flow (OPF) formulation was converted into a crisp OPF in a successive linear programming (SLP) framework and solved using an efficient interior point method (IPM). To test the efficacy of the proposed approach, simulations are performed on the IEEE 30-busand IEEE 118-bus test systems. The MFLP optimization is solved for several optimization cases. The obtained results are compared with those presented in the literature. A unique solution with a high satisfaction for the assigned targets is gained. Results demonstrate the effectiveness of the proposed MFLP technique in terms of solution optimality and rapid convergence. Moreover, the results indicate that using the optimal DG location with the MFLP algorithm provides the solution with the highest quality.
Estimating {Omega} from galaxy redshifts: Linear flow distortions and nonlinear clustering
Bromley, B.C. |; Warren, M.S.; Zurek, W.H.
1997-02-01
We propose a method to determine the cosmic mass density {Omega} from redshift-space distortions induced by large-scale flows in the presence of nonlinear clustering. Nonlinear structures in redshift space, such as fingers of God, can contaminate distortions from linear flows on scales as large as several times the small-scale pairwise velocity dispersion {sigma}{sub {nu}}. Following Peacock & Dodds, we work in the Fourier domain and propose a model to describe the anisotropy in the redshift-space power spectrum; tests with high-resolution numerical data demonstrate that the model is robust for both mass and biased galaxy halos on translinear scales and above. On the basis of this model, we propose an estimator of the linear growth parameter {beta}={Omega}{sup 0.6}/b, where b measures bias, derived from sampling functions that are tuned to eliminate distortions from nonlinear clustering. The measure is tested on the numerical data and found to recover the true value of {beta} to within {approximately}10{percent}. An analysis of {ital IRAS} 1.2 Jy galaxies yields {beta}=0.8{sub {minus}0.3}{sup +0.4} at a scale of 1000kms{sup {minus}1}, which is close to optimal given the shot noise and finite size of the survey. This measurement is consistent with dynamical estimates of {beta} derived from both real-space and redshift-space information. The importance of the method presented here is that nonlinear clustering effects are removed to enable linear correlation anisotropy measurements on scales approaching the translinear regime. We discuss implications for analyses of forthcoming optical redshift surveys in which the dispersion is more than a factor of 2 greater than in the {ital IRAS} data. {copyright} {ital 1997} {ital The American Astronomical Society}
NASA Astrophysics Data System (ADS)
Carmi, Raz; Yefremov, Nikolay; Bernstine, Hanna; Groshar, David
2014-03-01
A feasibility study of improved PET-CT tumor imaging approach is presented. A single PET-CT routine includes three different techniques: 18F-FDG early dynamic blood flow intended for perfusion assessment; standard late 18F-FDG uptake; and high-resolution contrast-enhanced CT enabling tissue texture analysis. Both PET protocols utilize the same single standard radiotracer dose administration. Quantitative volumetric arterial perfusion maps are derived from the reconstructed dynamic PET images corresponding to successive acquisition time intervals of 3 seconds only. For achieving high accuracy, the analysis algorithm differentiates the first-pass arterial flow from other interfering dynamic effects, and a noise reduction scheme based on adaptive total-variation minimization aims to provide appreciable quantitative map in physical conditions of high noise and low spatial resolution. The CT texture analysis comprises a practical and robust method for generating volumetric tissue irregularity maps. A local map value is represented by the entropy function which is derived from a weighted co-occurrence matrix histogram of the corresponding image voxel three-dimensional vicinity. Unique entropy scaling scheme and parameter optimization process, as well as appropriate scaling for varying image noise levels and contrast agent concentrations, improve the results toward quantitative absolute measure with respect to diverse scanning conditions and key analysis parameters. Representative imaging results are demonstrated on several clinical cases involving different organs and cancer types. In these cases, significant tumor characterization relative to the normal surrounding tissues is seen on the quantitative maps of all three imaging techniques. This proof of concept can lead the way to a new practical diagnostic imaging application.
Modeling Wave Driven Non-linear Flow Oscillations: The Terrestrial QBO and a Solar Analog
NASA Technical Reports Server (NTRS)
Mayr, Hans G.; Bhartia, P. K. (Technical Monitor)
2001-01-01
The Quasi Biennial Oscillation (QBO) of the zonal circulation observed in the terrestrial atmosphere at low latitudes is driven by wave mean flow interaction as was demonstrated first by Lindzen and Holton (1968), shown in a laboratory experiment by Plumb and McEwan (1978), and modeled by others (e.g., Plumb, Dunkerton). Although influenced by the seasonal cycle of solar forcing, the QBO, in principle, represents a nonlinear flow oscillation that can be maintained by a steady source of upward propagating waves. The wave driven non-linearity is of third or odd order in the flow velocity, which regenerates the fundamental harmonic itself to keep the oscillation going - the fluid dynamical analog of the displacement mechanism in the mechanical clock. Applying Hines' Doppler Spread Parameterization (DSP) for gravity waves (GW), we discuss with a global-scale spectral model numerical experiments that elucidate some properties of the QBO and its possible effects on the climatology of the atmosphere. Depending on the period of the QBO, wave filtering can cause interaction with the seasonal variations to produce pronounced oscillations with beat periods around 10 years. Since the seasonal cycle and its variability influence the period of the QBO, it may also be a potent conduit of solar activity variations to lower altitudes. Analogous to the terrestrial QBO, we propose that a flow oscillation may account for the 22-year periodicity of the solar magnetic cycle, potentially answering Dicke (1978) who asked, "Is there a chronometer hidden deep inside the Sun?" The oscillation would occur below the convection region, where gravity waves can propagate. Employing a simplified, analytic model, Hines' DSP is applied to estimate the flow oscillation. Depending on the adopted horizontal wavelengths of GW's, wave amplitudes less than 10 m/s can be made to produce oscillating zonal flows of about 20 m/s that should be large enough to generate a significant oscillation in the magnetic
Suspended particulate composition: evolution along a river linear and influence of regime flow
NASA Astrophysics Data System (ADS)
Le Meur, Mathieu; Montargès-Pelletier, Emmanuelle; Bauer, Allan; Gley, Renaud; Migot, Sylvie; Mansuy-Huault, Laurence; Lorgeoux, Catherine; Razafitianamaharavo, Angelina; Villièras, Frédéric
2015-04-01
Suspended Particulate Matters are recognized to play a crucial role in the transport and fate of chemicals like trace metal elements. The affinity of trace metals with natural SPM is influenced by (i) the nature of metal (ii) physical-chemical conditions of the water column (iii) SPM physical characteristics (grain size, surface area) (iiii) SPM chemical characteristics (elemental composition, mineralogy, organic composition). Some authors observed that the SPM composition was the predominant factor controlling the affinity of trace metals with natural SPM. One purpose of this work is to follow the physical and chemical characteristics of SPM along the river linear in order to better understand the affinity between SPM and heavy metals. One other purpose is to study the influence of regime flow on SPM physical and chemical composition in order to detect any variation of SPM composition with regime flow. SPM were sampled along Moselle river (North East of France) following an urbanization gradient. Two tributaries were also sampled, the Madon river which drains an agricultural catchment and the Fensch stream which flows through an ancient steel-making basin. SPM were sampled several times during high flow and low flow. Particulate matter was extracted on field using continuous flow field centrifuge. Frozen-dried samples were then characterized in terms of size distribution, elemental composition (ICP - AES, ICP - MS), mineralogy (XRD, FTIR, SEM, TEM), surface properties (gas adsorption techniques) and organic composition (Py-GC-MS and GC-MS). Grain size distribution evidenced the presence of coarser particles during high flow but no difference in the grain size distribution could be evidenced between the different stations. The grain size distribution of collected SPM appeared globally identical, although the increase of conductivity due to the junction of Meurthe river . In terms of composition, major element contents in SPM are characterized by the predominance of
Periodic two-dimensional cavity flow: Effect of linear horizontal thermal boundary condition
Jones, D.N. ); Briggs, D.G. )
1989-02-01
A two-dimensional air-filled cavity with isothermal vertical walls adiabatic top and bottom surfaces has been extensively studied both numerically and experimentally. When the aspect ratio is of order one and the Rayleigh number is less than about 10{sup 9} this geometry produces a highly stable and reproducible laminar flow. The result is quite different when the upper and lower surfaces are subjected to a destabilizing boundary condition, i.e., a linear temperature variation between the hot and cold vertical walls. At a critical Rayleigh number between 10{sup 6} and 10{sup 7} the flow becomes periodic and thus appears to fall into the category of instability of the type known as Hopf bifurcation. Briggs and Jones (1985) report velocity variations measured ner the vertical surfaces that vary by nearly {plus minus} 20% about the mean. Other unexplained behavior reported by Briggs and Jones (1985) consisted of jumps exhibited hysteresis effect, which resulted in some overlap between regimes. This paper presents the results of additional measurements, which indicate that the periodic flow is characterized by the convection of hot and cold pairs of thermals around the enclosure.
Linear stability of Couette flow of vibrationally non-equilibrium gas
NASA Astrophysics Data System (ADS)
Grigor'ev, Yurii N.; Ershov, Igor'V.
2016-10-01
Stability of the supersonic plane Couette flow of a perfect gas and of a vibrationally excited gas is studied within the framework of the linear theory. In both cases two variants are studied. When the transport coeffcients are taken as con-stant, and when they are dependent on the flow static temperature. The Satherland's viscosity law was used as temperature dependence of the shear viscosity. The thermal conductivity coeffcients caused by the translational, rotational and vibra-tional motions of gas molecules are determined by the Eucken's relations. Detailed comparison of the characteristics of the stability of the acoustic modes I and II for both viscosity models is carried out for a perfect gas. It is shown that the "viscous" stratification significantly increases flow stability as compared with the case of the constant viscosity model. It is obtained that characteristic features of development of viscous disturbances noted for the Sutherland's model are conserved for more simple model of the constant viscosity. The dissipative effect of the excitation of the vibrational mode is preserved in the case of the temperature dependence of the transport coeffcients. The relative decrease in growth rates of viscous modes I and II at the vibrational excitation is practically the same for both viscosity models. The increase in the critical Reynolds number is approximately 12 % in both cases.
Double-diffusive two-fluid flow in a slippery channel: A linear stability analysis
NASA Astrophysics Data System (ADS)
Ghosh, Sukhendu; Usha, R.; Sahu, Kirti Chandra
2014-12-01
The effect of velocity slip at the walls on the linear stability characteristics of two-fluid three-layer channel flow (the equivalent core-annular configuration in case of pipe) is investigated in the presence of double diffusive (DD) phenomenon. The fluids are miscible and consist of two solute species having different rates of diffusion. The fluids are assumed to be of the same density, but varying viscosity, which depends on the concentration of the solute species. It is found that the flow stabilizes when the less viscous fluid is present in the region adjacent to the slippery channel walls in the single-component (SC) system but becomes unstable at low Reynolds numbers in the presence of DD effect. As the mixed region of the fluids moves towards the channel walls, a new unstable mode (DD mode), distinct from the Tollman Schlichting (TS) mode, arises at Reynolds numbers smaller than the critical Reynolds number for the TS mode. We also found that this mode becomes more prominent when the mixed layer overlaps with the critical layer. It is shown that the slip parameter has nonmonotonic effect on the stability characteristics in this system. Through energy budget analysis, the dual role of slip is explained. The effect of slip is influenced by the location of mixed layer, the log-mobility ratio of the faster diffusing scalar, diffusivity, and the ratio of diffusion coefficients of the two species. Increasing the value of the slip parameter delays the first occurrence of the DD-mode. It is possible to achieve stabilization or destabilization by controlling the various physical parameters in the flow system. In the present study, we suggest an effective and realistic way to control three-layer miscible channel flow with viscosity stratification.
Are eruptions from linear fissures and caldera ring dykes more likely to produce pyroclastic flows?
NASA Astrophysics Data System (ADS)
Jessop, D. E.; Gilchrist, J.; Jellinek, A. M.; Roche, O.
2016-11-01
Turbulent volcanic jets are produced by highly-energetic explosive eruptions and may form buoyant plumes that rise many tens of kilometres into the atmosphere to form umbrella clouds or collapse to generate ground-hugging pyroclastic flows. Ash injected into the atmosphere can be transported for many hundreds of kilometres with the potential to affect climate, disrupt global air travel and cause respiratory health problems. Pyroclastic flows, by contrast, are potentially catastrophic to populations and infrastructure close to the volcano. Key to which of these two behaviours will occur is the extent to which the mechanical entrainment and mixing of ambient air into the jet by large (entraining) eddies forming the jet edge changes the density of the air-ash mixture: low entrainment rates lead to pyroclastic flows and high entrainment rates give rise to buoyant plumes. Recent experiments on particle-laden (multi-phase) volcanic jets from flared and straight-sided circular openings suggest that the likelihood for buoyant plumes will depend strongly on the shape and internal geometry of the vent region. This newly recognised sensitivity of the fate of volcanic jets to the structure of the vent is a consequence of a complex dynamic coupling between the jet and entrained solid particles, an effect that has generally been overlooked in previous studies. Building on this work, here we use an extensive series of experiments on multi-phase turbulent jets from analogue linear fissures and annular ring fractures to explore whether the restrictive vent geometry during cataclysmic caldera-forming (CCF) eruptions will ultimately lead a relatively greater frequency of pyroclastic flows than eruptions from circular vents on stratovolcanoes. Our results, understood through scaling analyses and a one-dimensional theoretical model, show that entrainment is enhanced where particle motions contribute angular momentum to entraining eddies. However, because the size of the entraining
Linear Aerospike SR-71 Experiment (LASRE) dumps water after first in-flight cold flow test
NASA Technical Reports Server (NTRS)
1998-01-01
The NASA SR-71A successfully completed its first cold flow flight as part of the NASA/Rocketdyne/Lockheed Martin Linear Aerospike SR-71 Experiment (LASRE) at NASA's Dryden Flight Research Center, Edwards, California on March 4, 1998. During a cold flow flight, gaseous helium and liquid nitrogen are cycled through the linear aerospike engine to check the engine's plumbing system for leaks and to check the engine operating characterisitics. Cold-flow tests must be accomplished successfully before firing the rocket engine experiment in flight. The SR-71 took off at 10:16 a.m. PST. The aircraft flew for one hour and fifty-seven minutes, reaching a maximum speed of Mach 1.58 before landing at Edwards at 12:13 p.m. PST. 'I think all in all we had a good mission today,' Dryden LASRE Project Manager Dave Lux said. Flight crew member Bob Meyer agreed, saying the crew 'thought it was a really good flight.' Dryden Research Pilot Ed Schneider piloted the SR-71 during the mission. Lockheed Martin LASRE Project Manager Carl Meade added, 'We are extremely pleased with today's results. This will help pave the way for the first in-flight engine data-collection flight of the LASRE.' The LASRE experiment was designed to provide in-flight data to help Lockheed Martin evaluate the aerodynamic characteristics and the handling of the SR-71 linear aerospike experiment configuration. The goal of the project was to provide in-flight data to help Lockheed Martin validate the computational predictive tools it was using to determine the aerodynamic performance of a future reusable launch vehicle. The joint NASA, Rocketdyne (now part of Boeing), and Lockheed Martin Linear Aerospike SR-71 Experiment (LASRE) completed seven initial research flights at Dryden Flight Research Center. Two initial flights were used to determine the aerodynamic characteristics of the LASRE apparatus (pod) on the back of the SR-71. Five later flights focused on the experiment itself. Two were used to cycle gaseous
A Vector Study of Linearized Supersonic Flow Applications to Nonplanar Problems
NASA Technical Reports Server (NTRS)
Martin, John C
1953-01-01
A vector study of the partial-differential equation of steady linearized supersonic flow is presented. General expressions which relate the velocity potential in the stream to the conditions on the disturbing surfaces, are derived. In connection with these general expressions the concept of the finite part of an integral is discussed. A discussion of problems dealing with planar bodies is given and the conditions for the solution to be unique are investigated. Problems concerning nonplanar systems are investigated, and methods are derived for the solution of some simple nonplanar bodies. The surface pressure distribution and the damping in roll are found for rolling tails consisting of four, six, and eight rectangular fins for the Mach number range where the region of interference between adjacent fins does not affect the fin tips.
Energy transportation via MITL by the linear current flow density up to 7 MA/cm
NASA Astrophysics Data System (ADS)
Korolev, V. D.; Bakshaev, Yu. L.; Bartov, A. V.; Blinov, P. I.; Bryzgunov, V. A.; Chernenko, A. S.; Dan'ko, S. A.; Kalinin, Yu. G.; Kingsep, A. S.; Kazakov, E. D.; Smirnov, V. P.; Smirnova, E. A.; Ustroev, G. I.
2006-10-01
The transmission properties of the magnetically self-insulated vacuum transporting line (MITL) were studied on the S-300 pulsed power machine (3 MA, 100 ns) at the high linear current flow density up to dI/db = 7 MA/cm. Experiments were carried out with the short line sections with 10 ÷ 15 mm length and 3 ÷ 5 mm vacuum gap. For measuring of the plasma parameters, the frame ICT photography with the nanosecond temporal resolution in the SXR range and ICT (Image Converter Tube) chronography in visible range were used. The X-ray radiation in various ranges was recorded by the XRD with thin filters (SXR) and by the semiconductor detectors (HXR). The information about current transmission efficiency was obtained by means of magnetic loops and low-inductance shunt. It was determined that dense plasma arose on both anode and cathode when the linear current flow density was low enough, dI/db ≤ 1 MA/cm. A dense plasma moves across the vacuum gap with the velocity (1 ÷ 2) × 106 cm/s. By recording the current and hard X-ray radiation it was found that electron losses in the current front did not exceed 10 ÷ 100 kA. Under strong magnetization of electrons r H = mvc/eB < d, these losses could be due to the motion of fast plasma component, which velocity exceeds 107 cm/s. Such a rare plasma sheath formed on the cathode by dI/db ≥ 1 MA/cm. Thereby the successful physical modeling of the recyclable MITL related to the Sandia Laboratories’ Conceptual Project of fusion reactor on the base of fast Z-pinch has been brought about.
A Linear Proportional Control of Turbulent Flow in a Planar Asymmetric Diffuser
NASA Astrophysics Data System (ADS)
Son, Donggun; Choi, Haecheon
2013-11-01
We perform a linear proportional control of turbulent flow in a planar asymmetric diffuser (Obi diffuser) for separation delay and pressure recovery. The Reynolds number based on the half of inlet channel height (δ) and bulk mean velocity (ub) is Reb =ub δ / ν = 9000 , which is the same condition as done by previous experimental and numerical studies. An actuation for the control is defined at the diffuser throat (x / δ = 0 to 1) as a wall-normal blowing and suction. A sensing variable (error) for the control is the difference between the instantaneous wall shear stresses at the upper and lower walls. The linear proportional control successfully suppresses the separation bubble at the lower slant wall and reduces the skin friction at the upper flat wall, resulting in the pressure recovery at the exit of diffuser. At an optimal proportional gain, the present control produces 6 . 7 % increase in the exit pressure with delayed separation. Supported by the NRF Program (NRF-2011-0028032, NRF-2012M2A8A4055647).
Mixing of a stable linear density stratification in Taylor-Couette flow
NASA Astrophysics Data System (ADS)
Oglethorpe, R. L. F.; Caulfield, C. P.; Woods, Andrew W.
2011-11-01
We consider mixing of an initially linear stable salt stratification in turbulent Taylor-Couette flow. The fluid is confined to a cylindrical annulus with a vertical axis. Mixing is caused by rotating the inner cylinder at a constant rate. The outer cylinder is fixed. Experimental measurements show that at high initial bulk Richardson number, defined as Ri0 =N2 /Ω2 , where N is the buoyancy frequency of the initial stratification and Ω is the rotation rate of the inner cylinder, an initially linear salt stratification develops a series of well mixed layers separated by sharp interfaces. The size of these layers appears to depend on Ri0 and the gap width between the cylinders, ΔR. With time, the layers at the top and bottom of the tank evolve in salinity. This leads to entrainment from and eventual mixing with the adjacent layers as the salinity contrast across these interfaces decreases. As a result of successive merger events, eventually the system becomes well mixed. The salinity of the inner layers appears to remain constant, so that salt is transported from the bottom layer to the top layer without changing the structure of the interior. The salt flux through an interface appears to depend only on the rotation rate Ω of the inner cylinder, consistent with our previous study for an initial two-layer salt stratification (Woods et al. (2010) J Fluid Mech. 663, 347-357).
Conduction in Low Mach Number Flows. I. Linear and Weakly Nonlinear Regimes
NASA Astrophysics Data System (ADS)
Lecoanet, Daniel; Brown, Benjamin P.; Zweibel, Ellen G.; Burns, Keaton J.; Oishi, Jeffrey S.; Vasil, Geoffrey M.
2014-12-01
Thermal conduction is an important energy transfer and damping mechanism in astrophysical flows. Fourier's law, in which the heat flux is proportional to the negative temperature gradient, leading to temperature diffusion, is a well-known empirical model of thermal conduction. However, entropy diffusion has emerged as an alternative thermal conduction model, despite not ensuring the monotonicity of entropy. This paper investigates the differences between temperature and entropy diffusion for both linear internal gravity waves and weakly nonlinear convection. In addition to simulating the two thermal conduction models with the fully compressible Navier-Stokes equations, we also study their effects in the reduced "soundproof" anelastic and pseudoincompressible (PI) equations. We find that in the linear and weakly nonlinear regime, temperature and entropy diffusion give quantitatively similar results, although there are some larger errors in the PI equations with temperature diffusion due to inaccuracies in the equation of state. Extrapolating our weakly nonlinear results, we speculate that differences between temperature and entropy diffusion might become more important for strongly turbulent convection.
CONDUCTION IN LOW MACH NUMBER FLOWS. I. LINEAR AND WEAKLY NONLINEAR REGIMES
Lecoanet, Daniel; Brown, Benjamin P.; Zweibel, Ellen G.; Burns, Keaton J.; Oishi, Jeffrey S.; Vasil, Geoffrey M.
2014-12-20
Thermal conduction is an important energy transfer and damping mechanism in astrophysical flows. Fourier's law, in which the heat flux is proportional to the negative temperature gradient, leading to temperature diffusion, is a well-known empirical model of thermal conduction. However, entropy diffusion has emerged as an alternative thermal conduction model, despite not ensuring the monotonicity of entropy. This paper investigates the differences between temperature and entropy diffusion for both linear internal gravity waves and weakly nonlinear convection. In addition to simulating the two thermal conduction models with the fully compressible Navier-Stokes equations, we also study their effects in the reduced ''soundproof'' anelastic and pseudoincompressible (PI) equations. We find that in the linear and weakly nonlinear regime, temperature and entropy diffusion give quantitatively similar results, although there are some larger errors in the PI equations with temperature diffusion due to inaccuracies in the equation of state. Extrapolating our weakly nonlinear results, we speculate that differences between temperature and entropy diffusion might become more important for strongly turbulent convection.
Hau, Jan-Niklas Oberlack, Martin; Chagelishvili, George; Khujadze, George; Tevzadze, Alexander
2015-12-15
Aerodynamic sound generation in shear flows is investigated in the light of the breakthrough in hydrodynamics stability theory in the 1990s, where generic phenomena of non-normal shear flow systems were understood. By applying the thereby emerged short-time/non-modal approach, the sole linear mechanism of wave generation by vortices in shear flows was captured [G. D. Chagelishvili, A. Tevzadze, G. Bodo, and S. S. Moiseev, “Linear mechanism of wave emergence from vortices in smooth shear flows,” Phys. Rev. Lett. 79, 3178-3181 (1997); B. F. Farrell and P. J. Ioannou, “Transient and asymptotic growth of two-dimensional perturbations in viscous compressible shear flow,” Phys. Fluids 12, 3021-3028 (2000); N. A. Bakas, “Mechanism underlying transient growth of planar perturbations in unbounded compressible shear flow,” J. Fluid Mech. 639, 479-507 (2009); and G. Favraud and V. Pagneux, “Superadiabatic evolution of acoustic and vorticity perturbations in Couette flow,” Phys. Rev. E 89, 033012 (2014)]. Its source is the non-normality induced linear mode-coupling, which becomes efficient at moderate Mach numbers that is defined for each perturbation harmonic as the ratio of the shear rate to its characteristic frequency. Based on the results by the non-modal approach, we investigate a two-dimensional homentropic constant shear flow and focus on the dynamical characteristics in the wavenumber plane. This allows to separate from each other the participants of the dynamical processes — vortex and wave modes — and to estimate the efficacy of the process of linear wave-generation. This process is analyzed and visualized on the example of a packet of vortex modes, localized in both, spectral and physical, planes. Further, by employing direct numerical simulations, the wave generation by chaotically distributed vortex modes is analyzed and the involved linear and nonlinear processes are identified. The generated acoustic field is anisotropic in the wavenumber
NASA Astrophysics Data System (ADS)
Hau, Jan-Niklas; Chagelishvili, George; Khujadze, George; Oberlack, Martin; Tevzadze, Alexander
2015-12-01
Aerodynamic sound generation in shear flows is investigated in the light of the breakthrough in hydrodynamics stability theory in the 1990s, where generic phenomena of non-normal shear flow systems were understood. By applying the thereby emerged short-time/non-modal approach, the sole linear mechanism of wave generation by vortices in shear flows was captured [G. D. Chagelishvili, A. Tevzadze, G. Bodo, and S. S. Moiseev, "Linear mechanism of wave emergence from vortices in smooth shear flows," Phys. Rev. Lett. 79, 3178-3181 (1997); B. F. Farrell and P. J. Ioannou, "Transient and asymptotic growth of two-dimensional perturbations in viscous compressible shear flow," Phys. Fluids 12, 3021-3028 (2000); N. A. Bakas, "Mechanism underlying transient growth of planar perturbations in unbounded compressible shear flow," J. Fluid Mech. 639, 479-507 (2009); and G. Favraud and V. Pagneux, "Superadiabatic evolution of acoustic and vorticity perturbations in Couette flow," Phys. Rev. E 89, 033012 (2014)]. Its source is the non-normality induced linear mode-coupling, which becomes efficient at moderate Mach numbers that is defined for each perturbation harmonic as the ratio of the shear rate to its characteristic frequency. Based on the results by the non-modal approach, we investigate a two-dimensional homentropic constant shear flow and focus on the dynamical characteristics in the wavenumber plane. This allows to separate from each other the participants of the dynamical processes — vortex and wave modes — and to estimate the efficacy of the process of linear wave-generation. This process is analyzed and visualized on the example of a packet of vortex modes, localized in both, spectral and physical, planes. Further, by employing direct numerical simulations, the wave generation by chaotically distributed vortex modes is analyzed and the involved linear and nonlinear processes are identified. The generated acoustic field is anisotropic in the wavenumber plane, which
Energetics of slope flows: linear and weakly nonlinear solutions of the extended Prandtl model
NASA Astrophysics Data System (ADS)
Güttler, Ivan; Marinović, Ivana; Večenaj, Željko; Grisogono, Branko
2016-07-01
The Prandtl model succinctly combines the 1D stationary boundary-layer dynamics and thermodynamics of simple anabatic and katabatic flows over uniformly inclined surfaces. It assumes a balance between the along-the-slope buoyancy component and adiabatic warming/cooling, and the turbulent mixing of momentum and heat. In this study, energetics of the Prandtl model is addressed in terms of the total energy (TE) concept. Furthermore, since the authors recently developed a weakly nonlinear version of the Prandtl model, the TE approach is also exercised on this extended model version, which includes an additional nonlinear term in the thermodynamic equation. Hence, interplay among diffusion, dissipation and temperature-wind interaction of the mean slope flow is further explored. The TE of the nonlinear Prandtl model is assessed in an ensemble of solutions where the Prandtl number, the slope angle and the nonlinearity parameter are perturbed. It is shown that nonlinear effects have the lowest impact on variability in the ensemble of solutions of the weakly nonlinear Prandtl model when compared to the other two governing parameters. The general behavior of the nonlinear solution is similar to the linear solution, except that the maximum of the along-the-slope wind speed in the nonlinear solution reduces for larger slopes. Also, the dominance of PE near the sloped surface, and the elevated maximum of KE in the linear and nonlinear energetics of the extended Prandtl model are found in the PASTEX-94 measurements. The corresponding level where KE>PE most likely marks the bottom of the sublayer subject to shear-driven instabilities. Finally, possible limitations of the weakly nonlinear solutions of the extended Prandtl model are raised. In linear solutions, the local storage of TE term is zero, reflecting the stationarity of solutions by definition. However, in nonlinear solutions, the diffusion, dissipation and interaction terms (where the height of the maximum interaction is
Renormalizability of the gradient flow in the 2D O(N) non-linear sigma model
NASA Astrophysics Data System (ADS)
Makino, Hiroki; Suzuki, Hiroshi
2015-03-01
It is known that the gauge field and its composite operators evolved by the Yang-Mills gradient flow are ultraviolet (UV) finite without any multiplicative wave function renormalization. In this paper, we prove that the gradient flow in the 2D O(N) non-linear sigma model possesses a similar property: The flowed N-vector field and its composite operators are UV finite without multiplicative wave function renormalization. Our proof in all orders of perturbation theory uses a (2+1)-dimensional field theoretical representation of the gradient flow, which possesses local gauge invariance without gauge field. As an application of the UV finiteness of the gradient flow, we construct the energy-momentum tensor in the lattice formulation of the O(N) non-linear sigma model that automatically restores the correct normalization and the conservation law in the continuum limit.
The coalescence of two equal-sized drops in a two-dimensional linear flow
NASA Astrophysics Data System (ADS)
Yang, Hong; Park, C. Charles; Hu, Y. Thomas; Leal, L. Gary
2001-05-01
A four-roll mill was used to experimentally investigate the coalescence of two equal-sized drops in general linear flows. The experimental system consisted of polybutadiene drops suspended in polydimethylsiloxane. Under the experimental conditions studied, the bulk-phase rheological properties of both fluids are Newtonian. We studied both head-on collisions for a purely extensional "hyperbolic" flow that always lead to coalescence, and collisions with a finite offset from the inflow axis for several different flow types produced in the four-roll mill. The experimental results have been compared with approximate theoretical predictions of coalescence, based on an asymptotic theory for small capillary number, where the drops are spherical apart from a small planar deformation at the frontal surfaces between the two drops. In head-on collisions, it was found experimentally that the product of the film drainage time and strain rate is independent of capillary number (Ca) and drop radius at very low Ca. This scaling behavior agrees qualitatively with theoretical predictions from the approximate small Ca theory. At higher values of Ca, this dimensionless drainage time varies as Ca3/2. This scaling is also consistent with theoretical predictions. For collisions with a nonzero offset from the head-on configuration, coalescence occurs only for capillary numbers below a critical value, Cac. Measurements were made of Cac as a function of the drop size and the flow type, for various values of the offset. The critical capillary number for coalescence was found to decrease with increasing offset, in qualitative agreement with predictions from the theoretical model. However, these Cac versus offset results do not agree quantitatively with the theoretical predictions. In the model the minimum film thickness occurs when the two-drop pair has rotated to the angle at which the external flow just begins to pull them apart. However, for configurations with small but nonzero offsets, it
Sheared-flow induced confinement transition in a linear magnetized plasma
Zhou, S.; Heidbrink, W. W.; Boehmer, H.; McWilliams, R.; Carter, T. A.; Vincena, S.; Friedman, B.; Schaffner, D.
2012-01-15
A magnetized plasma cylinder (12 cm in diameter) is induced by an annular shape obstacle at the Large Plasma Device [W. Gekelman, H. Pfister, Z. Lucky, J. Bamber, D. Leneman, and J. Maggs, Rev. Sci. Instrum. 62, 2875 (1991)]. Sheared azimuthal flow is driven at the edge of the plasma cylinder through edge biasing. Strong fluctuations of density and potential ({delta}n/n{approx}e{delta}{phi}/kT{sub e}{approx}0.5) are observed at the plasma edge, accompanied by a large density gradient (L{sub n}={nabla}lnn{sup -1}{approx}2cm) and shearing rate ({gamma}{approx}300kHz). Edge turbulence and cross-field transport are modified by changing the bias voltage (V{sub bias}) on the obstacle and the axial magnetic field (B{sub z}) strength. In cases with low V{sub bias} and large B{sub z}, improved plasma confinement is observed, along with steeper edge density gradients. The radially sheared flow induced by ExB drift dramatically changes the cross-phase between density and potential fluctuations, which causes the wave-induced particle flux to reverse its direction across the shear layer. In cases with higher bias voltage or smaller B{sub z}, large radial transport and rapid depletion of the central plasma density are observed. Two-dimensional cross-correlation measurement shows that a mode with azimuthal mode number m=1 and large radial correlation length dominates the outward transport in these cases. Linear analysis based on a two-fluid Braginskii model suggests that the fluctuations are driven by both density gradient (drift wave like) and flow shear (Kelvin-Helmholtz like) at the plasma edge.
Blanchard, M.; Schuller, T.; Sipp, D.; Schmid, P. J.
2015-04-15
The response of a laminar premixed methane-air flame subjected to flow perturbations around a steady state is examined experimentally and using a linearized compressible Navier-Stokes solver with a one-step chemistry mechanism to describe combustion. The unperturbed flame takes an M-shape stabilized both by a central bluff body and by the external rim of a cylindrical nozzle. This base flow is computed by a nonlinear direct simulation of the steady reacting flow, and the flame topology is shown to qualitatively correspond to experiments conducted under comparable conditions. The flame is then subjected to acoustic disturbances produced at different locations in the numerical domain, and its response is examined using the linearized solver. This linear numerical model then allows the componentwise investigation of the effects of flow disturbances on unsteady combustion and the feedback from the flame on the unsteady flow field. It is shown that a wrinkled reaction layer produces hydrodynamic disturbances in the fresh reactant flow field that superimpose on the acoustic field. This phenomenon, observed in several experiments, is fully interpreted here. The additional perturbations convected by the mean flow stem from the feedback of the perturbed flame sheet dynamics onto the flow field by a mechanism similar to that of a perturbed vortex sheet. The different regimes where this mechanism prevails are investigated by examining the phase and group velocities of flow disturbances along an axis oriented along the main direction of the flow in the fresh reactant flow field. It is shown that this mechanism dominates the low-frequency response of the wrinkled shape taken by the flame and, in particular, that it fully determines the dynamics of the flame tip from where the bulk of noise is radiated.
Abgrall, Rémi; Congedo, Pietro Marco
2013-02-15
This paper deals with the formulation of a semi-intrusive (SI) method allowing the computation of statistics of linear and non linear PDEs solutions. This method shows to be very efficient to deal with probability density function of whatsoever form, long-term integration and discontinuities in stochastic space. Given a stochastic PDE where randomness is defined on Ω, starting from (i) a description of the solution in term of a space variables, (ii) a numerical scheme defined for any event ω∈Ω and (iii) a (family) of random variables that may be correlated, the solution is numerically described by its conditional expectancies of point values or cell averages and its evaluation constructed from the deterministic scheme. One of the tools is a tessellation of the random space as in finite volume methods for the space variables. Then, using these conditional expectancies and the geometrical description of the tessellation, a piecewise polynomial approximation in the random variables is computed using a reconstruction method that is standard for high order finite volume space, except that the measure is no longer the standard Lebesgue measure but the probability measure. This reconstruction is then used to formulate a scheme on the numerical approximation of the solution from the deterministic scheme. This new approach is said semi-intrusive because it requires only a limited amount of modification in a deterministic solver to quantify uncertainty on the state when the solver includes uncertain variables. The effectiveness of this method is illustrated for a modified version of Kraichnan–Orszag three-mode problem where a discontinuous pdf is associated to the stochastic variable, and for a nozzle flow with shocks. The results have been analyzed in terms of accuracy and probability measure flexibility. Finally, the importance of the probabilistic reconstruction in the stochastic space is shown up on an example where the exact solution is computable, the viscous
NASA Technical Reports Server (NTRS)
Carmichael, R. L.; Erickson, L. L.
1981-01-01
PAN AIR is a computer program for predicting subsonic or supersonic linear potential flow about arbitrary configurations. It uses linear source and quadratic doublet strength distributions. These higher-order distributions have been implemented in a manner that greatly reduces the numerical stability problems that have plagued earlier attempts to make surface paneling methods work successfully for supersonic flow. PAN AIR's problem-solving capability, numerical approach, modeling features, and program architecture are described. Numerical results are presented for a variety of geometries at supersonic Mach numbers.
Linear stability of optimal streaks in the log-layer of turbulent channel flows
NASA Astrophysics Data System (ADS)
Alizard, Frédéric
2015-10-01
The importance of secondary instability of streaks for the generation of vortical structures attached to the wall in the logarithmic region of turbulent channels is studied. The streaks and their linear instability are computed by solving equations associated with the organized motion that include an eddy-viscosity modeling the effect of incoherent fluctuations. Three friction Reynolds numbers, Reτ = 2000, 3000, and 5000, are investigated. For all flow cases, optimal streamwise vortices (i.e., having the highest potential for linear transient energy amplification) are used as initial conditions. Due to the lift-up mechanism, these optimal perturbations lead to the nonlinear growth of streaks. Based on a Floquet theory along the spanwise direction, we observe the onset of streak secondary instability for a wide range of spanwise wavelengths when the streak amplitude exceeds a critical value. Under neutral conditions, it is shown that streak instability modes have their energy mainly concentrated in the overlap layer and propagate with a phase velocity equal to the mean streamwise velocity of the log-layer. These neutral log-layer modes exhibit a sinuous pattern and have characteristic sizes that are proportional to the wall distance in both streamwise and spanwise directions, in agreement with the Townsend's attached eddy hypothesis (A. Townsend, the structure of turbulent shear flow, Cambridge university press, 1976 2nd edition). In particular, for a distance from the wall varying from y+ ≈ 100 (in wall units) to y ≈ 0.3h, where h is half the height of the channel, the neutral log-layer modes are self-similar with a spanwise width of λz ≈ y/0.3 and a streamwise length of λx ≈ 3λz, independently of the Reynolds number. Based on this observation, it is suggested that compact vortical structures attached to the wall can be ascribed to streak secondary instabilities. In addition, spatial distributions of fluctuating vorticity components show that the onset
NASA Astrophysics Data System (ADS)
Iwasaki, Toshiki; Shimizu, Yasuyuki; Kimura, Ichiro
2016-06-01
A number of numerical models have been proposed to understand and simulate fluvial river morphodynamics; however, it is somewhat unclear whether all the models are able to consistently simulate flow-bed instability phenomena. This study investigates the sensitivity of free bar morphology in rivers to secondary flow models used in depth-averaged models using linear stability analyses and numerical simulations. Both the linear analyses and numerical simulations suggest that under certain hydraulic conditions, an equilibrium-type secondary flow model, which has been widely used in river morphodynamic models, fails to generate a finite wavelength and bar mode, allowing the inception of bars of infinitely short scale and infinitely high mode. Using a nonequilibrium-type secondary flow model avoids the unphysical formation of these incipient free bars, and gives better solutions regarding finite amplitude bars. Since free bars are essential, intrinsic river morphological features, the findings of this study can be applied to a wide range of river morphodynamic calculations.
Linear stability of a circular Couette flow under a radial thermoelectric body force.
Yoshikawa, H N; Meyer, A; Crumeyrolle, O; Mutabazi, I
2015-03-01
The stability of the circular Couette flow of a dielectric fluid is analyzed by a linear perturbation theory. The fluid is confined between two concentric cylindrical electrodes of infinite length with only the inner one rotating. A temperature difference and an alternating electric tension are applied to the electrodes to produce a radial dielectrophoretic body force that can induce convection in the fluid. We examine the effects of superposition of this thermoelectric force with the centrifugal force including its thermal variation. The Earth's gravity is neglected to focus on the situations of a vanishing Grashof number such as microgravity conditions. Depending on the electric field strength and of the temperature difference, critical modes are either axisymmetric or nonaxisymmetric, occurring in either stationary or oscillatory states. An energetic analysis is performed to determine the dominant destabilizing mechanism. When the inner cylinder is hotter than the outer one, the circular Couette flow is destabilized by the centrifugal force for weak and moderate electric fields. The critical mode is steady axisymmetric, except for weak fields within a certain range of the Prandtl number and of the radius ratio of the cylinders, where the mode is oscillatory and axisymmetric. The frequency of this oscillatory mode is correlated with a Brunt-Väisälä frequency due to the stratification of both the density and the electric permittivity of the fluid. Under strong electric fields, the destabilization by the dielectrophoretic force is dominant, leading to oscillatory nonaxisymmetric critical modes with a frequency scaled by the frequency of the inner-cylinder rotation. When the outer cylinder is hotter than the inner one, the instability is again driven by the centrifugal force. The critical mode is axisymmetric and either steady under weak electric fields or oscillatory under strong electric fields. The frequency of the oscillatory mode is also correlated with the
Wave Driven Non-Linear Flow Oscillator for the 22-Year Solar Cycle
NASA Technical Reports Server (NTRS)
Mayr, H. G.; Wolff, C. L.; Hartle, R. E.; Einaudi, Franco (Technical Monitor)
2000-01-01
We propose that waves generate an oscillation in the Sun to account for the 22-year magnetic cycle. The mechanism we envision is analogous to that driving the Quasi Biennial Oscillation (QBO) observed in the terrestrial atmosphere, which is well understood in principal. Planetary waves and gravity waves deposit momentum in the background atmosphere and accelerate the flow under viscous dissipation. Analysis shows that such a momentum source represents a non-linearity of third or generally odd order, which generates also the fundamental frequency/period so that an oscillation is maintained without external time dependent forcing. For the Sun, we propose that the wave driven oscillation would occur just below the convection region, where the buoyancy frequency or convective stability becomes small to favor wave breaking and wave mean flow interaction. Using scale analysis to extrapolate from terrestrial to solar conditions, we present results from a simplified analytical model, applied to the equator, that incorporates Hines'Doppler Spread Parameterization for gravity waves (GW). Based on a parametric study, we conclude: (1) Depending on the adopted horizontal wavelengths of GW's, wave amplitudes < 10 m/s can be made to produce oscillating zonal winds of about 25 m/s that should be large enough to generate a corresponding oscillation in the main poloidal magnetic field; (2) The oscillation period can be made to be 22 years provided the buoyancy frequency (stability) is sufficiently small, which would place the oscillating wind field near the base of the convection region; (3) In this region, the turbulence associated with wave processes would be enhanced by low stability, and this also helps to produce the desired oscillation period and generate the dynamo currents that would produce the reversing magnetic field. We suggest that the above mechanism may also drive other long-period metronomes in planetary and stellar interiors.
Linear ground-water flow, flood-wave response program for programmable calculators
Kernodle, John Michael
1978-01-01
Two programs are documented which solve a discretized analytical equation derived to determine head changes at a point in a one-dimensional ground-water flow system. The programs, written for programmable calculators, are in widely divergent but commonly encountered languages and serve to illustrate the adaptability of the linear model to use in situations where access to true computers is not possible or economical. The analytical method assumes a semi-infinite aquifer which is uniform in thickness and hydrologic characteristics, bounded on one side by an impermeable barrier and on the other parallel side by a fully penetrating stream in complete hydraulic connection with the aquifer. Ground-water heads may be calculated for points along a line which is perpendicular to the impermeable barrie and the fully penetrating stream. Head changes at the observation point are dependent on (1) the distance between that point and the impermeable barrier, (2) the distance between the line of stress (the stream) and the impermeable barrier, (3) aquifer diffusivity, (4) time, and (5) head changes along the line of stress. The primary application of the programs is to determine aquifer diffusivity by the flood-wave response technique. (Woodard-USGS)
Generalized linear stability of non-inertial rimming flow in a rotating horizontal cylinder.
Aggarwal, Himanshu; Tiwari, Naveen
2015-10-01
The stability of a thin film of viscous liquid inside a horizontally rotating cylinder is studied using modal and non-modal analysis. The equation governing the film thickness is derived within lubrication approximation and up to first order in aspect ratio (average film thickness to radius of the cylinder). Effect of gravity, viscous stress and capillary pressure are considered in the model. Steady base profiles are computed in the parameter space of interest that are uniform in the axial direction. A linear stability analysis is performed on these base profiles to study their stability to axial perturbations. The destabilizing behavior of aspect ratio and surface tension is demonstrated which is attributed to capillary instability. The transient growth that gives maximum amplification of any initial disturbance and the pseudospectra of the stability operator are computed. These computations reveal weak effect of non-normality of the operator and the results of eigenvalue analysis are recovered after a brief transient period. Results from nonlinear simulations are also presented which also confirm the validity of the modal analysis for the flow considered in this study. PMID:26496740
Shang, Yu; Yu, Guoqiang
2014-09-29
Conventional semi-infinite analytical solutions of correlation diffusion equation may lead to errors when calculating blood flow index (BFI) from diffuse correlation spectroscopy (DCS) measurements in tissues with irregular geometries. Very recently, we created an algorithm integrating a Nth-order linear model of autocorrelation function with the Monte Carlo simulation of photon migrations in homogenous tissues with arbitrary geometries for extraction of BFI (i.e., αD{sub B}). The purpose of this study is to extend the capability of the Nth-order linear algorithm for extracting BFI in heterogeneous tissues with arbitrary geometries. The previous linear algorithm was modified to extract BFIs in different types of tissues simultaneously through utilizing DCS data at multiple source-detector separations. We compared the proposed linear algorithm with the semi-infinite homogenous solution in a computer model of adult head with heterogeneous tissue layers of scalp, skull, cerebrospinal fluid, and brain. To test the capability of the linear algorithm for extracting relative changes of cerebral blood flow (rCBF) in deep brain, we assigned ten levels of αD{sub B} in the brain layer with a step decrement of 10% while maintaining αD{sub B} values constant in other layers. Simulation results demonstrate the accuracy (errors < 3%) of high-order (N ≥ 5) linear algorithm in extracting BFIs in different tissue layers and rCBF in deep brain. By contrast, the semi-infinite homogenous solution resulted in substantial errors in rCBF (34.5% ≤ errors ≤ 60.2%) and BFIs in different layers. The Nth-order linear model simplifies data analysis, thus allowing for online data processing and displaying. Future study will test this linear algorithm in heterogeneous tissues with different levels of blood flow variations and noises.
NASA Astrophysics Data System (ADS)
Pasquon, K.; Gargani, J.; Massé, M.
2015-10-01
Linear Gullies are seasonal processes located on the intra-crater dunes fields. They are mainly located between 43°40'S and 52°2'S on dunes with a slight slope (˜13°) facing SSW (mainly between 150°N and 260°N). The progression of Linear Gullies happens every years between the end of winter and the beginning of spring (between Ls 167.4° and Ls 216.6°), when the CO finally defrosts on the dunes fields. Each year, a Recurrent Diffusing Flow spreads on Linear Gullies area from the end of winter (Ls 167.4°) to the beginning of autumn (Ls 21.9°), with a maximum activity between Ls 167.4° and Ls 192.3°. This flow takes an active part in the Linear Gullies creation/upkeep and could participate to the pits development. We highlight an albedo decrease of 42% during the pits activity. This important and very transient decreasing could be hardly explained by a dry movement only. We thus suggest that the Recurrent Diffusing Flows could be linked to the presence of a fluid or a liquid spreading in the shallow sub-surface. A link between CO cycle and the Linear Gullies could be consistent with their development timing. Brines participation can't be excluded.
Linear stability of radially-heated circular Couette flow with simulated radial gravity
NASA Astrophysics Data System (ADS)
Tagg, Randy; Weidman, Patrick D.
2007-05-01
The stability of circular Couette flow between vertical concentric cylinders in the presence of a radial temperature gradient is considered with an effective “radial gravity.” In addition to terrestrial buoyancy - ρg e z we include the term - ρg m f(r)e r where g m f(r) is the effective gravitational acceleration directed radially inward across the gap. Physically, this body force arises in experiments using ferrofluid in the annular gap of a Taylor Couette cell whose inner cylinder surrounds a vertical stack of equally spaced disk magnets. The radial dependence f(r) of this force is proportional to the modified Bessel function K 1(κr), where 2π/κ is the spatial period of the magnetic stack and r is the radial coordinate. Linear stability calculations made to compare with conditions reported by Ali and Weidman (J. Fluid Mech., 220, 1990) show strong destabilization effects, measured by the onset Rayleigh number R, when the inner wall is warmer, and strong stabilization effects when the outer wall is warmer, with increasing values of the dimensionless radial gravity γ = g m /g. Further calculations presented for the geometry and fluid properties of a terrestrial laboratory experiment reveal a hitherto unappreciated structure of the stability problem for differentially-heated cylinders: multiple wavenumber minima exist in the marginal stability curves. Transitions in global minima among these curves give rise to a competition between differing instabilities of the same spiral mode number, but widely separated axial wavenumbers.
Chandra, S.; Grimm, R.A.; Katz, R.; Thomas, J.D.
1996-06-01
The aim of this study was to better understand and characterize left atrial appendage flow in atrial fibrillation. Atrial fibrillation and flutter are the most common cardiac arrhythmias affecting 15% of the older population. The pulsed Doppler velocity profile data was recorded from the left atrial appendage of patients using transesophageal echocardiography. The data was analyzed using Fourier analysis and nonlinear dynamical tools. Fourier analysis showed that appendage mechanical frequency ({ital f{sub f}}) for patients in sinus rhythm was always lower (around1 Hz) than that in atrial fibrillation (5-8 Hz). Among patients with atrial fibrillation spectral power below {ital f{sub f}} was significantly different suggesting variability within this group of patients. Results that suggested the presence of nonlinear dynamics were: a) the existence of two arbitrary peak frequencies {ital f{sub 1}, f{sub 2}}, and other peak frequencies as linear combinations thereof ({ital mf{sub 1}{+-}nf{sub 2}}), and b) the similarity between the spectrum of patient data and that obtained using the Lorenz equation. Nonlinear analysis tools, including Phase plots and differential radial plots, were also generated from the velocity data using a delay of 10. In the phase plots, some patients displayed a torus-like structure, while others had a more random-like pattern. In the differential radial plots, the first set of patients (with torus-like phase plots) showed fewer values crossing an arbitrary threshold of 10 than did the second set (8 vs. 27 in one typical example). The outcome of cardioversion was different for these two set of patients. Fourier analysis helped to: differentiate between sinus rhythm and atrial fibrillation, understand the characteristics of the wide range of atrial fibrillation patients, and provide hints that atrial fibrillation could be a nonlinear process. Nonlinear dynamical tools helped to further characterize and sub-classify atrial fibrillation.
Computer Program For Linear Algebra
NASA Technical Reports Server (NTRS)
Krogh, F. T.; Hanson, R. J.
1987-01-01
Collection of routines provided for basic vector operations. Basic Linear Algebra Subprogram (BLAS) library is collection from FORTRAN-callable routines for employing standard techniques to perform basic operations of numerical linear algebra.
NASA Astrophysics Data System (ADS)
Mustafa, M.; Khan, Junaid Ahmad
2015-07-01
Present work deals with the magneto-hydro-dynamic flow and heat transfer of Casson nanofluid over a non-linearly stretching sheet. Non-linear temperature distribution across the sheet is considered. More physically acceptable model of passively controlled wall nanoparticle volume fraction is accounted. The arising mathematical problem is governed by interesting parameters which include Casson fluid parameter, magnetic field parameter, power-law index, Brownian motion parameter, thermophoresis parameter, Prandtl number and Schmidt number. Numerical solutions are computed through fourth-fifth-order-Runge-Kutta integration approach combined with the shooting technique. Both temperature and nanoparticle volume fraction are increasing functions of Casson fluid parameter.
NASA Astrophysics Data System (ADS)
Desjardins, Tiffany
2015-11-01
Various bias electrodes have been inserted into the Helicon-Cathode (HelCat) device at the University of New Mexico, in order to affect intrinsic drift-wave turbulence and flows. The goal of the experiments was to suppress and effect the intrinsic turbulence and with detailed measurements, understand the changes that occur during biasing. The drift-mode in HelCat varies from coherent at low magnetic field (<1kG) to broad-band turbulent at high magnetic fields (>1kG). The first electrode consists of 6 concentric rings set in a ceramic substrate; these rings act as a boundary condition, sitting at the end of the plasma column 2-m away from the source. A negative bias has been found to have no effect on the fluctuations, but a positive bias (Vr>5Te) is required in order to suppress the drift-mode. Two molybdenum grids can also be inserted into the plasma and sit close to the source. Floating or grounding a grid results in suppressing the drift-mode of the system. A negative bias (>-5Te) is found to return the drift-mode, and it is possible to drive a once coherent mode into a broad-band turbulent one. From a bias voltage of -5Te
NASA Astrophysics Data System (ADS)
Lu, Liang; Papadakis, George
2011-09-01
The aim of this paper is to investigate the receptivity of cylinder wake to external periodic flow pulsation at low Reynolds number using linear stability analysis. The inlet flow pulsation appears as a forcing term in the linearised equation set. The full non-linear N-S equations as well as the linearised set for small perturbations around the time-averaged flow are solved using an in-house finite volume solver. The results are first validated against reference data for growth rate and frequency of the most unstable eigenmode for flow past a fixed cylinder with steady base flow at various Reynolds numbers. A special numerical technique is developed to separate the components of the solution in the wake that vary with the natural shedding frequency and the external pulsating frequency. The developed approach requires temporal integration over one period of vortex shedding and solution of a 4×4 linear system at every cell of the domain. The results show that both cross-stream and streamwise velocity components in the near cylinder region are strongly affected by flow pulsation, and its effect is spatially localised in the near wake. Increasing the pulsation frequency reduces the spatial extent within which pulsation plays an important role. A symmetric shedding pattern is established and at every period of external pulsation, two pairs of symmetric vortices are shed from the top and bottom of the cylinder. The width of the wake periodically widens and narrows, which is similar to "wake breathing" observed in a streamwise oscillating cylinder.
Hard-sphere dispersions: Small-wave-vector structure-factor measurements in a linear shear flow
NASA Astrophysics Data System (ADS)
Ackerson, Bruce J.; van der Werff, Jos; de Kruif, C. G.
1988-06-01
Small-scattering-wave-vector structure-factor measurements have been made for model hard-sphere suspensions undergoing a steady linear shear flow. The samples are comprised of sterically stabilized silica particles in cyclohexane and have been well characterized previously by rheological, light scattering, and neutron scattering measurements. These combined measurements provide a strict test of recent theories of microscopic order in suspensions undergoing shear and suggest a picture which unifies several intuitive notions about suspensions undergoing shear flow: distortion of the pair correlation function, clustering, layering, and nonequilibrium phase transitions.
Mustafa, M.; Mushtaq, A.; Hayat, T.; Alsaedi, A.
2016-01-01
Present study explores the MHD three-dimensional rotating flow and heat transfer of ferrofluid induced by a radiative surface. The base fluid is considered as water with magnetite-Fe3O4 nanoparticles. Novel concept of non-linear radiative heat flux is considered which produces a non-linear energy equation in temperature field. Conventional transformations are employed to obtain the self-similar form of the governing differential system. The arising system involves an interesting temperature ratio parameter which is an indicator of small/large temperature differences in the flow. Numerical simulations with high precision are determined by well-known shooting approach. Both uniform stretching and rotation have significant impact on the solutions. The variation in velocity components with the nanoparticle volume fraction is non-monotonic. Local Nusselt number in Fe3O4–water ferrofluid is larger in comparison to the pure fluid even at low particle concentration. PMID:26894690
Mustafa, M; Mushtaq, A; Hayat, T; Alsaedi, A
2016-01-01
Present study explores the MHD three-dimensional rotating flow and heat transfer of ferrofluid induced by a radiative surface. The base fluid is considered as water with magnetite-Fe3O4 nanoparticles. Novel concept of non-linear radiative heat flux is considered which produces a non-linear energy equation in temperature field. Conventional transformations are employed to obtain the self-similar form of the governing differential system. The arising system involves an interesting temperature ratio parameter which is an indicator of small/large temperature differences in the flow. Numerical simulations with high precision are determined by well-known shooting approach. Both uniform stretching and rotation have significant impact on the solutions. The variation in velocity components with the nanoparticle volume fraction is non-monotonic. Local Nusselt number in Fe3O4-water ferrofluid is larger in comparison to the pure fluid even at low particle concentration. PMID:26894690
Eddy, drift wave and zonal flow dynamics in a linear magnetized plasma
Arakawa, H.; Inagaki, S.; Sasaki, M.; Kosuga, Y.; Kobayashi, T.; Kasuya, N.; Nagashima, Y.; Yamada, T.; Lesur, M.; Fujisawa, A.; Itoh, K.; Itoh, S.-I.
2016-01-01
Turbulence and its structure formation are universal in neutral fluids and in plasmas. Turbulence annihilates global structures but can organize flows and eddies. The mutual-interactions between flow and the eddy give basic insights into the understanding of non-equilibrium and nonlinear interaction by turbulence. In fusion plasma, clarifying structure formation by Drift-wave turbulence, driven by density gradients in magnetized plasma, is an important issue. Here, a new mutual-interaction among eddy, drift wave and flow in magnetized plasma is discovered. A two-dimensional solitary eddy, which is a perturbation with circumnavigating motion localized radially and azimuthally, is transiently organized in a drift wave – zonal flow (azimuthally symmetric band-like shear flows) system. The excitation of the eddy is synchronized with zonal perturbation. The organization of the eddy has substantial impact on the acceleration of zonal flow. PMID:27628894
Eddy, drift wave and zonal flow dynamics in a linear magnetized plasma
NASA Astrophysics Data System (ADS)
Arakawa, H.; Inagaki, S.; Sasaki, M.; Kosuga, Y.; Kobayashi, T.; Kasuya, N.; Nagashima, Y.; Yamada, T.; Lesur, M.; Fujisawa, A.; Itoh, K.; Itoh, S.-I.
2016-09-01
Turbulence and its structure formation are universal in neutral fluids and in plasmas. Turbulence annihilates global structures but can organize flows and eddies. The mutual-interactions between flow and the eddy give basic insights into the understanding of non-equilibrium and nonlinear interaction by turbulence. In fusion plasma, clarifying structure formation by Drift-wave turbulence, driven by density gradients in magnetized plasma, is an important issue. Here, a new mutual-interaction among eddy, drift wave and flow in magnetized plasma is discovered. A two-dimensional solitary eddy, which is a perturbation with circumnavigating motion localized radially and azimuthally, is transiently organized in a drift wave – zonal flow (azimuthally symmetric band-like shear flows) system. The excitation of the eddy is synchronized with zonal perturbation. The organization of the eddy has substantial impact on the acceleration of zonal flow.
Eddy, drift wave and zonal flow dynamics in a linear magnetized plasma.
Arakawa, H; Inagaki, S; Sasaki, M; Kosuga, Y; Kobayashi, T; Kasuya, N; Nagashima, Y; Yamada, T; Lesur, M; Fujisawa, A; Itoh, K; Itoh, S-I
2016-01-01
Turbulence and its structure formation are universal in neutral fluids and in plasmas. Turbulence annihilates global structures but can organize flows and eddies. The mutual-interactions between flow and the eddy give basic insights into the understanding of non-equilibrium and nonlinear interaction by turbulence. In fusion plasma, clarifying structure formation by Drift-wave turbulence, driven by density gradients in magnetized plasma, is an important issue. Here, a new mutual-interaction among eddy, drift wave and flow in magnetized plasma is discovered. A two-dimensional solitary eddy, which is a perturbation with circumnavigating motion localized radially and azimuthally, is transiently organized in a drift wave - zonal flow (azimuthally symmetric band-like shear flows) system. The excitation of the eddy is synchronized with zonal perturbation. The organization of the eddy has substantial impact on the acceleration of zonal flow. PMID:27628894
Development of flow network analysis code for block type VHTR core by linear theory method
Lee, J. H.; Yoon, S. J.; Park, J. W.; Park, G. C.
2012-07-01
VHTR (Very High Temperature Reactor) is high-efficiency nuclear reactor which is capable of generating hydrogen with high temperature of coolant. PMR (Prismatic Modular Reactor) type reactor consists of hexagonal prismatic fuel blocks and reflector blocks. The flow paths in the prismatic VHTR core consist of coolant holes, bypass gaps and cross gaps. Complicated flow paths are formed in the core since the coolant holes and bypass gap are connected by the cross gap. Distributed coolant was mixed in the core through the cross gap so that the flow characteristics could not be modeled as a simple parallel pipe system. It requires lot of effort and takes very long time to analyze the core flow with CFD analysis. Hence, it is important to develop the code for VHTR core flow which can predict the core flow distribution fast and accurate. In this study, steady state flow network analysis code is developed using flow network algorithm. Developed flow network analysis code was named as FLASH code and it was validated with the experimental data and CFD simulation results. (authors)
Massoudi, Mehrdad; Phuoc, Tran X.
2008-09-25
In this paper, we study the flow of a compressible (density-gradient-dependent) non-linear fluid down an inclined plane, subject to radiation boundary condition. The convective heat transfer is also considered where a source team, similar to the Arrhenius type reaction, is included. The non-dimensional forms of the equations are solved numerically and the competing effects of conduction, dissipation, heat generation and radiation are discussed.
Massoudi, Mehrdad; Tran, P.X.
2008-09-22
In this paper, we study the flow of a compressible (density-gradient-dependent) non-linear fluid down an inclined plane, subject to radiation boundary condition. The convective heat transfer is also considered where a source term, similar to the Arrhenius type reaction, is included. The non-dimensional forms of the equations are solved numerically and the competing effects of conduction, dissipation, heat generation and radiation are discussed
NASA Astrophysics Data System (ADS)
Joshi, Deepti; St-Hilaire, André; Daigle, Anik; Ouarda, Taha B. M. J.
2013-04-01
SummaryThis study attempts to compare the performance of two statistical downscaling frameworks in downscaling hydrological indices (descriptive statistics) characterizing the low flow regimes of three rivers in Eastern Canada - Moisie, Romaine and Ouelle. The statistical models selected are Relevance Vector Machine (RVM), an implementation of Sparse Bayesian Learning, and the Automated Statistical Downscaling tool (ASD), an implementation of Multiple Linear Regression. Inputs to both frameworks involve climate variables significantly (α = 0.05) correlated with the indices. These variables were processed using Canonical Correlation Analysis and the resulting canonical variates scores were used as input to RVM to estimate the selected low flow indices. In ASD, the significantly correlated climate variables were subjected to backward stepwise predictor selection and the selected predictors were subsequently used to estimate the selected low flow indices using Multiple Linear Regression. With respect to the correlation between climate variables and the selected low flow indices, it was observed that all indices are influenced, primarily, by wind components (Vertical, Zonal and Meridonal) and humidity variables (Specific and Relative Humidity). The downscaling performance of the framework involving RVM was found to be better than ASD in terms of Relative Root Mean Square Error, Relative Mean Absolute Bias and Coefficient of Determination. In all cases, the former resulted in less variability of the performance indices between calibration and validation sets, implying better generalization ability than for the latter.
Archambeau, C.B.
1994-01-01
A fractured solid under stress loading (or unloading) can be viewed as behaving macroscopically as a medium with internal, hidden, degrees of freedom, wherein changes in fracture geometry (i.e. opening, closing and extension) and flow of fluid and gas within fractures will produce major changes in stresses and strains within the solid. Likewise, the flow process within fractures will be strongly coupled to deformation within the solid through boundary conditions on the fracture surfaces. The effects in the solid can, in part, be phenomenologically represented as inelastic or plastic processes in the macroscopic view. However, there are clearly phenomena associated with fracture growth and open fracture fluid flows that produce effects that can not be described using ordinary inelastic phenomenology. This is evident from the fact that a variety of energy release phenomena can occur, including seismic emissions of previously stored strain energy due to fracture growth, release of disolved gas from fluids in the fractures resulting in enhanced buoyancy and subsequent energetic flows of gas and fluids through the fracture system which can produce raid extension of old fractures and the creation of new ones. Additionally, the flows will be modulated by the opening and closing of fractures due to deformation in the solid, so that the flow process is strongly coupled to dynamical processes in the surrounding solid matrix, some of which are induced by the flow itself.
NASA Astrophysics Data System (ADS)
Tsamopoulos, John; Karapetsas, George
2013-11-01
It is well known that during extrusion of viscoelastic fluids various flow instabilities may arise resulting in a distorted free surface. In order to investigate the factors generating these instabilities we perform a linear stability analysis at zero Reynolds number around the steady solution of the cylindrical or planar stick-slip flow for a viscoelastic fluid following the PTT model. The stick-slip flow is an important special case of the extrudate swell problem, since the latter reduces to it in the limit of infinite surface tension. We will show that the flow becomes unstable as the Weissenberg number increases above a critical value, due to a Hopf bifurcation suggesting that the flow will become periodic in time. Both the critical value of the Weissenberg number and the frequency of the instability depend strongly on the rheological parameters of the viscoelastic model. The elasticity alone can be responsible for the appearance of instabilities in the extrusion process of viscoelastic fluids and the often used assumptions of wall slip or compressibility, although they might be present, are not required. Finally, the mechanisms that produce these instabilities are examined through energy analysis of the disturbance flow. The authors would like to acknowledge the financial support by the General Secretariat of Research and Technology of Greece under the Action ``Supporting Postdoctoral Researchers'' (Grant No: PE8/906), and under the ``Excellence Program'' (Grant No: 1918)
Huang, A.B.; Yortsos, Y.C.
1984-09-01
This paper reports on the continuation of previous work in the linear stability of immiscible, two-phase flow displacement processes in porous media that includes continuously changing mobility and capillary effects. In Part I simple basic-flow profiles that allow exact solutions to be obtained were investigated. First, the stability of non-capillary flows corresponding to a straight line fractional flow is examined. Next, the stability of capillary flows for general basic flow profiles is examined. For values of the viscosity ratio above the critical, the numerical results show that the displacement is unstable to small disturbances of wavelength larger than a critical value, and stable otherwise. This effect is attributed to the stabilizing action of capillarity. Values of wavelength corresponding to the highest rate of growth are numerically determined. It is found that stability is enhanced at lower values of the capillary number and the injection rate. Finally, a limited sensitivity study of the effect on stability of the functional forms of relative permeability and capillary pressure is carried out.
NASA Astrophysics Data System (ADS)
Xin, Bo; Sun, Dakun; Jing, Xiaodong; Sun, Xiaofeng
2016-07-01
Lined ducts are extensively applied to suppress noise emission from aero-engines and other turbomachines. The complex noise/flow interaction in a lined duct possibly leads to acoustic instability in certain conditions. To investigate the instability, the full linearized Navier-Stokes equations with eddy viscosity considered are solved in frequency domain using a Galerkin finite element method to compute the sound transmission in shear flow in the lined duct as well as the flow perturbation over the impedance wall. A good agreement between the numerical predictions and the published experimental results is obtained for the sound transmission, showing that a transmission peak occurs around the resonant frequency of the acoustic liner in the presence of shear flow. The eddy viscosity is an important influential factor that plays the roles of both providing destabilizing and making coupling between the acoustic and flow motions over the acoustic liner. Moreover, it is shown from the numerical investigation that the occurrence of the sound amplification and the magnitude of transmission coefficient are closely related to the realistic velocity profile, and we find it essential that the actual variation of the velocity profile in the axial direction over the liner surface be included in the computation. The simulation results of the periodic flow patterns possess the proper features of the convective instability over the liner, as observed in Marx et al.'s experiment. A quantitative comparison between numerical and experimental results of amplitude and phase of the instability is performed. The corresponding eigenvalues achieve great agreement.
Silliman, Brian R.; McCoy, Michael W.; Trussell, Geoffrey C.; Crain, Caitlin M.; Ewanchuk, Patrick J.; Bertness, Mark D.
2013-01-01
Although consumers can strongly influence community recovery from disturbance, few studies have explored the effects of consumer identity and density and how they may vary across abiotic gradients. On rocky shores in Maine, recent experiments suggest that recovery of plant- or animal- dominated community states is governed by rates of water movement and consumer pressure. To further elucidate the mechanisms of consumer control, we examined the species-specific and density-dependent effects of rocky shore consumers (crabs and snails) on community recovery under both high (mussel dominated) and low flow (plant dominated) conditions. By partitioning the direct impacts of predators (crabs) and grazers (snails) on community recovery across a flow gradient, we found that grazers, but not predators, are likely the primary agent of consumer control and that their impact is highly non-linear. Manipulating snail densities revealed that herbivorous and bull-dozing snails (Littorina littorea) alone can control recovery of high and low flow communities. After ∼1.5 years of recovery, snail density explained a significant amount of the variation in macroalgal coverage at low flow sites and also mussel recovery at high flow sites. These density-dependent grazer effects were were both non-linear and flow-dependent, with low abundance thresholds needed to suppress plant community recovery, and much higher levels needed to control mussel bed development. Our study suggests that consumer density and identity are key in regulating both plant and animal community recovery and that physical conditions can determine the functional forms of these consumer effects. PMID:23940510
Silliman, Brian R; McCoy, Michael W; Trussell, Geoffrey C; Crain, Caitlin M; Ewanchuk, Patrick J; Bertness, Mark D
2013-01-01
Although consumers can strongly influence community recovery from disturbance, few studies have explored the effects of consumer identity and density and how they may vary across abiotic gradients. On rocky shores in Maine, recent experiments suggest that recovery of plant- or animal- dominated community states is governed by rates of water movement and consumer pressure. To further elucidate the mechanisms of consumer control, we examined the species-specific and density-dependent effects of rocky shore consumers (crabs and snails) on community recovery under both high (mussel dominated) and low flow (plant dominated) conditions. By partitioning the direct impacts of predators (crabs) and grazers (snails) on community recovery across a flow gradient, we found that grazers, but not predators, are likely the primary agent of consumer control and that their impact is highly non-linear. Manipulating snail densities revealed that herbivorous and bull-dozing snails (Littorina littorea) alone can control recovery of high and low flow communities. After ∼1.5 years of recovery, snail density explained a significant amount of the variation in macroalgal coverage at low flow sites and also mussel recovery at high flow sites. These density-dependent grazer effects were were both non-linear and flow-dependent, with low abundance thresholds needed to suppress plant community recovery, and much higher levels needed to control mussel bed development. Our study suggests that consumer density and identity are key in regulating both plant and animal community recovery and that physical conditions can determine the functional forms of these consumer effects. PMID:23940510
Frequency-domain Monte Carlo method for linear oscillatory gas flows
NASA Astrophysics Data System (ADS)
Ladiges, Daniel R.; Sader, John E.
2015-03-01
Gas flows generated by resonating nanoscale devices inherently occur in the non-continuum, low Mach number regime. Numerical simulations of such flows using the standard direct simulation Monte Carlo (DSMC) method are hindered by high statistical noise, which has motivated the development of several alternate Monte Carlo methods for low Mach number flows. Here, we present a frequency-domain low Mach number Monte Carlo method based on the Boltzmann-BGK equation, for the simulation of oscillatory gas flows. This circumvents the need for temporal simulations, as is currently required, and provides direct access to both amplitude and phase information using a pseudo-steady algorithm. The proposed method is validated for oscillatory Couette flow and the flow generated by an oscillating sphere. Good agreement is found with an existing time-domain method and accurate numerical solutions of the Boltzmann-BGK equation. Analysis of these simulations using a rigorous statistical approach shows that the frequency-domain method provides a significant improvement in computational speed.
Sputum culture ... There, it is placed in a special dish (culture). It is then watched to see if bacteria ... Chernecky CC, Berger BJ. Culture, routine. In: Chernecky CC, Berger BJ, ... . 6th ed. Philadelphia, PA: Elsevier Saunders; 2013:409- ...
... Listen Español Text Size Email Print Share The Importance of Family Routines Page Content Every family needs ... child to sleep. These rituals can include storytelling, reading aloud, conversation, and songs. Try to avoid exciting ...
NASA Technical Reports Server (NTRS)
Anderson, Patrick L.; Amoroso, Michael T.
1990-01-01
Viewgraphs on daily exercise routines are presented. Topics covered include: daily exercise and periodic stress testings; exercise equipment; physiological monitors; exercise protocols; physiological levels; equipment control; control systems; and fuzzy logic control.
Evaluation of multi-well test data in a faulted aquifer using linear and radial flow models
Allen, D.M.; Michel, F.A.
1998-11-01
An extensive drilling and testing program was undertaken at Carleton University, Ottawa, Canada, to characterize the aquifer for the design of an aquifer thermal energy storage (ATES) system. The substantial data base provides an excellent record of well yields and hydraulic responses to a series of aquifer tests in a faulted carbonate aquifer. Well yield variability is reflected in the wide range in specific capacity and is dependent upon the proximity of a well to a major fault. Constant discharge data, available for nine pumping wells and several observation wells, reflect both the excellent hydraulic connection along major faults and the limited hydraulic connection between fault blocks. Three different flow models, including vertical fracture and vertical dyke (linear), and Theis (radial), are used to interpret constant discharge test data from nine pumping wells and several observation wells. In all tests, the duration of pumping is sufficient to identify early-time linear flow along faults and late-time pseudo-radial flow between fault blocks. This paper demonstrates the influence of fault-induced heterogeneity on the hydraulic response of a carbonate aquifer and demonstrates the application and limitation of simple radial continuum models to aquifers of this type.
Airfoil wake and linear theory gust response including sub and superresonant flow conditions
NASA Technical Reports Server (NTRS)
Henderson, Gregory H.; Fleeter, Sanford
1992-01-01
The unsteady aerodynamic gust response of a high solidity stator vane row is examined in terms of the fundamental gust modeling assumptions with particular attention given to the effects near an acoustic resonance. A series of experiments was performed with gusts generated by rotors comprised of perforated plates and airfoils. It is concluded that, for both the perforated plate and airfoil wake generated gusts, the unsteady pressure responses do not agree with the linear-theory gust predictions near an acoustic resonance. The effects of the acoustic resonance phenomena are clearly evident on the airfoil surface unsteady pressure responses. The transition of the measured lift coefficients across the acoustic resonance from the subresonant regime to the superresonant regime occurs in a simple linear fashion.
Non-analytic vortex core and non-linear vortex flow in bosonic superfluids
NASA Astrophysics Data System (ADS)
Agam, O.; Aleiner, I. L.
2015-11-01
We analyze the disorder limited motion of quantum vortices in a two-dimensional bosonic superfluid with a large healing length. It is shown that the excitations of low-energy degrees of freedom associated with the non-analytic reconstruction of the vortex core (Ann. Phys., 346 (2014) 195) determine strong non-linear effects in the vortex transport at velocities much smaller than Landau's critical velocity. Experiments are suggested to verify our predictions.
NASA Astrophysics Data System (ADS)
Khan, Masood; Hashim; Hussain, M.; Azam, M.
2016-08-01
This paper presents a study of the magnetohydrodynamic (MHD) boundary layer flow of a non-Newtonian Carreau fluid over a convectively heated surface. The analysis of heat transfer is further performed in the presence of non-linear thermal radiation. The appropriate transformations are employed to bring the governing equations into dimensionless form. The numerical solutions of the partially coupled non-linear ordinary differential equations are obtained by using the Runge-Kutta Fehlberg integration scheme. The influence of non-dimensional governing parameters on the velocity, temperature, local skin friction coefficient and local Nusselt number is studied and discussed with the help of graphs and tables. Results proved that there is significant decrease in the velocity and the corresponding momentum boundary layer thickness with the growth in the magnetic parameter. However, a quite the opposite is true for the temperature and the corresponding thermal boundary layer thickness.
Laskowski, Gregory Michael
2005-12-01
Flows with strong curvature present a challenge for turbulence models, specifically eddy viscosity type models which assume isotropy and a linear and instantaneous equilibrium relation between stress and strain. Results obtained from three different codes and two different linear eddy viscosity turbulence models are compared to a DNS simulation in order to gain some perspective on the turbulence modeling capability of SIERRA/Fuego. The Fuego v2f results are superior to the more common two-layer k-e model results obtained with both a commercial and research code in terms of the concave near wall behavior predictions. However, near the convex wall, including the separated region, little improvement is gained using the v2f model and in general the turbulent kinetic energy prediction is fair at best.
Quantitation of protein orientation in flow-oriented unilamellar liposomes by linear dichroism
NASA Astrophysics Data System (ADS)
Rajendra, Jascindra; Damianoglou, Angeliki; Hicks, Matthew; Booth, Paula; Rodger, P. Mark; Rodger, Alison
2006-07-01
The linear dichroism of the visible wavelength transitions of retinal have been used to analyse linear dichroism spectra to determine the orientation of aromatic and peptide structural motifs of Bacteriorhodopsin incorporated into unilamellar soy bean liposomes. The results are consistent with the available X-ray data. This proves that visible light absorbing chromophores can be used to analyse linear dichroism data to give the orientation of membrane proteins in membrane mimicking environments. The work has been extended by screening a wide range of hydrophobic molecules with high extinction coefficients in transitions above 300 nm to find molecules that could be used as independent probes of liposome orientation for experiments involving proteins incorporated into liposomes. Three probes were found to have potential for future work: bis-(1,3-dibutylbarbituric acid)pentamethine oxonol (DiBAC 4), retinol and rhodamine B. All three can be used to determine the orientation of the porphyrin of cytochrome c, the aromatic residues of gramicidin and the helices of both proteins. The orientation parameter, S, for the liposomes varied from batch to batch of unilamellar liposomes prepared by extruding through a 100 nm membrane. The value and variation in S was 0.030 ± 0.010. Repeat experiments with the same batch of liposomes showed less variation. Film LD data were measured for DiBAC 4 and rhodamine B to determine the polarisations of their long wavelength transitions.
NASA Astrophysics Data System (ADS)
Ostrovski, Georg; van Strien, Sebastian
2011-02-01
In this paper we consider a class of piecewise affine Hamiltonian vector fields whose orbits are piecewise straight lines. We give a first classification result of such systems and show that the orbit-structure of the flow of such a differential equation is surprisingly rich.
NASA Astrophysics Data System (ADS)
Damiano, E. R.; Long, D. S.; Smith, M. L.
2004-08-01
An approach is presented that uses velocimetry data to estimate accurately the spatial distribution of viscosity in steady laminar parallel flows of incompressible linearly viscous fluids. The approach is generally applicable to Newtonian fluids with spatially varying viscosity or to particle-suspension flows where a non-uniform distribution of the particles contributes to spatial variations in the local effective viscosity of the suspension. Emphasis is placed on the application of these methods to steady axisymmetric blood flow in cylindrical glass capillary tubes and microvessels. In this context, the spatial variations in viscosity over the vessel cross-section are predicted where it is assumed that the rheological properties associated with a heterogeneous red blood cell suspension can be well approximated by a continuous generalized linearly viscous fluid having a spatially non-uniform viscosity. For such a fluid, an expression for the viscosity profile over the vessel cross-section is derived that satisfies the conservation principles of mass and momentum and depends upon the a priori determined velocity distribution, which is extracted from fluorescent micro-particle image velocimetry data obtained from microvessels in vivo. These profiles provide useful information about dynamic, kinematic and rheological properties of the flow that include expressions for the axial pressure-gradient component, the local shear stress distribution, and the relative apparent viscosity. In microvessels, the effect of the glycocalyx surface layer on the vessel wall is also accounted for in the analysis by modelling the layer as a uniformly thick porous medium. Velocimetry data are presented from in vivo measurements made in venules after the application of a light-dye treatment to degrade the glycocalyx. Results reveal that these methods are sufficiently sensitive to detect a reduction in glycocalyx thickness of {˜} 0.3 umum, which represents a fractional decrease in
Schilling, K.E.; Wolter, C.F.
2005-01-01
Nineteen variables, including precipitation, soils and geology, land use, and basin morphologic characteristics, were evaluated to develop Iowa regression models to predict total streamflow (Q), base flow (Qb), storm flow (Qs) and base flow percentage (%Qb) in gauged and ungauged watersheds in the state. Discharge records from a set of 33 watersheds across the state for the 1980 to 2000 period were separated into Qb and Qs. Multiple linear regression found that 75.5 percent of long term average Q was explained by rainfall, sand content, and row crop percentage variables, whereas 88.5 percent of Qb was explained by these three variables plus permeability and floodplain area variables. Qs was explained by average rainfall and %Qb was a function of row crop percentage, permeability, and basin slope variables. Regional regression models developed for long term average Q and Qb were adapted to annual rainfall and showed good correlation between measured and predicted values. Combining the regression model for Q with an estimate of mean annual nitrate concentration, a map of potential nitrate loads in the state was produced. Results from this study have important implications for understanding geomorphic and land use controls on streamflow and base flow in Iowa watersheds and similar agriculture dominated watersheds in the glaciated Midwest. (JAWRA) (Copyright ?? 2005).
Bohling, G.C.; Butler, J.J.
2001-01-01
We have developed a program for inverse analysis of two-dimensional linear or radial groundwater flow problems. The program, 1r2dinv, uses standard finite difference techniques to solve the groundwater flow equation for a horizontal or vertical plane with heterogeneous properties. In radial mode, the program simulates flow to a well in a vertical plane, transforming the radial flow equation into an equivalent problem in Cartesian coordinates. The physical parameters in the model are horizontal or x-direction hydraulic conductivity, anisotropy ratio (vertical to horizontal conductivity in a vertical model, y-direction to x-direction in a horizontal model), and specific storage. The program allows the user to specify arbitrary and independent zonations of these three parameters and also to specify which zonal parameter values are known and which are unknown. The Levenberg-Marquardt algorithm is used to estimate parameters from observed head values. Particularly powerful features of the program are the ability to perform simultaneous analysis of heads from different tests and the inclusion of the wellbore in the radial mode. These capabilities allow the program to be used for analysis of suites of well tests, such as multilevel slug tests or pumping tests in a tomographic format. The combination of information from tests stressing different vertical levels in an aquifer provides the means for accurately estimating vertical variations in conductivity, a factor profoundly influencing contaminant transport in the subsurface. ?? 2001 Elsevier Science Ltd. All rights reserved.
Transition to asymmetry in pipe flow of shear-thinning fluids: a linear instability?
NASA Astrophysics Data System (ADS)
Dennis, David; Wen, Chaofan; Poole, Robert
2015-11-01
Previous studies of shear-thinning fluids in pipe flow discovered that, although the time-averaged velocity profile was axisymmetric when the flow was laminar or fully turbulent, contrary to expectations it was asymmetric in the laminar-turbulent transition regime. We reveal that in fact the asymmetry is not induced by the laminar-turbulent transition process, but is an instability of the laminar state. Furthermore, the transition process is responsible for returning symmetry to the flow (i.e. the opposite to what was previously believed), which explains why the fully turbulent case is axisymmetric. The experiment was performed using an aqueous solution of xanthan gum (0.15%), an essentially inelastic shear-thinning polymer solution. Stereoscopic particle image velocimetry was used to measure the 3C velocity vectors over the entire circular cross-section of the pipe, 220 pipe diameters downstream of the inlet. The deviation from the axisymmetric laminar state is observed to develop in the form of a supercritical bifurcation with square-root dependence on Reynolds number. The asymmetry is non-hysteretic and reversible, not only having a favoured location, but a preferred route between axisymmetry and asymmetry, which it adheres to regardless of the direction of the transition.
Linear stability of a Berman flow in a channel partially filled with a porous medium
NASA Astrophysics Data System (ADS)
Deng, Chuntao; Martinez, D. Mark
2005-02-01
The temporal stability of similarity solutions for an incompressible fluid moving in a channel partially filled with a porous medium is analyzed. A constant wall suction acting on the bottom surface of the porous medium drives the fluid; the upper wall of the channel is impermeable. This work extends the work of King and Cox ["Asymptotic analysis of the steady-state and time-dependent Berman problem," J. Eng. Math. 39, 87 (2001)] to a wider class of similarity solutions where coupled flow, both above and through a porous medium, is considered. In this work, a similarity transform is proposed which satisfies both the Navier-Stokes equation in the clear fluid portion of the domain and the Brinkman extended Darcy law relationship in the porous medium. The boundary conditions between the clear fluid and porous regions are those outlined by Ochoa-Tapia and Whitaker ["Momentum transfer at the boundary between a porous medium and a homogeneous fluid I: theoretical development," Int. J. Heat Mass Transfer 38, 2635 (1995)]. The solutions of the steady flow are approximated analytically, in the limit of small wall suction, and numerically. Multiple steady-state solutions were found. The temporal stability of the solutions indicates turning-point bifurcations and instability only occurred with reverse flows.
Shang, Yu; Lin, Yu; Yu, Guoqiang; Li, Ting; Chen, Lei; Toborek, Michal
2014-05-12
Conventional semi-infinite solution for extracting blood flow index (BFI) from diffuse correlation spectroscopy (DCS) measurements may cause errors in estimation of BFI (αD{sub B}) in tissues with small volume and large curvature. We proposed an algorithm integrating Nth-order linear model of autocorrelation function with the Monte Carlo simulation of photon migrations in tissue for the extraction of αD{sub B}. The volume and geometry of the measured tissue were incorporated in the Monte Carlo simulation, which overcome the semi-infinite restrictions. The algorithm was tested using computer simulations on four tissue models with varied volumes/geometries and applied on an in vivo stroke model of mouse. Computer simulations shows that the high-order (N ≥ 5) linear algorithm was more accurate in extracting αD{sub B} (errors < ±2%) from the noise-free DCS data than the semi-infinite solution (errors: −5.3% to −18.0%) for different tissue models. Although adding random noises to DCS data resulted in αD{sub B} variations, the mean values of errors in extracting αD{sub B} were similar to those reconstructed from the noise-free DCS data. In addition, the errors in extracting the relative changes of αD{sub B} using both linear algorithm and semi-infinite solution were fairly small (errors < ±2.0%) and did not rely on the tissue volume/geometry. The experimental results from the in vivo stroke mice agreed with those in simulations, demonstrating the robustness of the linear algorithm. DCS with the high-order linear algorithm shows the potential for the inter-subject comparison and longitudinal monitoring of absolute BFI in a variety of tissues/organs with different volumes/geometries.
NASA Astrophysics Data System (ADS)
Shang, Yu; Li, Ting; Chen, Lei; Lin, Yu; Toborek, Michal; Yu, Guoqiang
2014-05-01
Conventional semi-infinite solution for extracting blood flow index (BFI) from diffuse correlation spectroscopy (DCS) measurements may cause errors in estimation of BFI (αDB) in tissues with small volume and large curvature. We proposed an algorithm integrating Nth-order linear model of autocorrelation function with the Monte Carlo simulation of photon migrations in tissue for the extraction of αDB. The volume and geometry of the measured tissue were incorporated in the Monte Carlo simulation, which overcome the semi-infinite restrictions. The algorithm was tested using computer simulations on four tissue models with varied volumes/geometries and applied on an in vivo stroke model of mouse. Computer simulations shows that the high-order (N ≥ 5) linear algorithm was more accurate in extracting αDB (errors < ±2%) from the noise-free DCS data than the semi-infinite solution (errors: -5.3% to -18.0%) for different tissue models. Although adding random noises to DCS data resulted in αDB variations, the mean values of errors in extracting αDB were similar to those reconstructed from the noise-free DCS data. In addition, the errors in extracting the relative changes of αDB using both linear algorithm and semi-infinite solution were fairly small (errors < ±2.0%) and did not rely on the tissue volume/geometry. The experimental results from the in vivo stroke mice agreed with those in simulations, demonstrating the robustness of the linear algorithm. DCS with the high-order linear algorithm shows the potential for the inter-subject comparison and longitudinal monitoring of absolute BFI in a variety of tissues/organs with different volumes/geometries.
NASA Astrophysics Data System (ADS)
Dunstan, Jocelyn; Lee, Kyoung Jin; Park, Simon; Goldstein, Raymond E.
A novel form of convection was observed in a suspension of non-motile Photobacterium phosphoreum bacteria. The pattern resembles classical bioconvection, however this strain has limited if any motility, which excludes this possible explanation. After performing a series of control experiments we found that the convection was actually driven by the evaporation of the salty bacterial medium, and the same kind of plumes were observed using polystyrene beads suspended in water with salt added. A mathematical model was formulated for the process and studied using a linear stability analysis and finite element method simulations, reproducing most of the observed experimental features. From the linear stability analysis, a threshold in salt concentration to observe convective motion was obtained, as well as the wavelength of the pattern at the onset of the instability. This was complemented by finite element simulations, which produced plume dynamics remarkably similar to the experimental observations. Evaporation-driven convection on the millimeter scale has not been studied extensively, and its effect may have been underestimated in other experiments.
Linear and nonlinear instability and ligament dynamics in 3D laminar two-layer liquid/liquid flows
NASA Astrophysics Data System (ADS)
Ó Náraigh, Lennon; Valluri, Prashant; Scott, David; Bethune, Iain; Spelt, Peter
2013-11-01
We consider the linear and nonlinear stability of two-phase density-matched but viscosity contrasted fluids subject to laminar Poiseuille flow in a channel, paying particular attention to the formation of three-dimensional waves. The Orr-Sommerfeld-Squire analysis is used along with DNS of the 3D two-phase Navier-Stokes equations using our newly launched TPLS Solver (http://edin.ac/10cRKzS). For the parameter regimes considered, we demonstrate the existence of two distinct mechanisms whereby 3D waves enter the system, and dominate at late time. There exists a direct route, whereby 3D waves are amplified by the standard linear mechanism; for certain parameter classes, such waves grow at a rate less than but comparable to that of most-dangerous two-dimensional mode. Additionally, there is a weakly nonlinear route, whereby a purely spanwise wave couples to a streamwise mode and grows exponentially. We demonstrate these mechanisms in isolation and in concert. Consideration is also given to the ultimate state of these waves: persistent three-dimensional nonlinear waves are stretched and distorted by the base flow, thereby producing regimes of ligaments, ``sheets,'' or ``interfacial turbulence.'' HECToR RAP/dCSE Project e174, HPC-Europa 2.
Linear analysis of time dependent properties of Child-Langmuir flow
NASA Astrophysics Data System (ADS)
Rokhlenko, A.
2013-01-01
We continue our analysis of the time dependent behavior of the electron flow in the Child-Langmuir system, removing an approximation used earlier. We find a modified set of oscillatory decaying modes with frequencies of the same order as the inverse of the electron transient time. This range (typically MHz) allows simple experimental detection and maybe exploitation. We then study the time evolution of the current in response to a slow change of the anode voltage where the same modes of oscillations appear too. The cathode current in this case is systematically advanced or retarded depending on the direction of the voltage change.
Linear analysis of time dependent properties of Child-Langmuir flow
Rokhlenko, A.
2013-01-15
We continue our analysis of the time dependent behavior of the electron flow in the Child-Langmuir system, removing an approximation used earlier. We find a modified set of oscillatory decaying modes with frequencies of the same order as the inverse of the electron transient time. This range (typically MHz) allows simple experimental detection and maybe exploitation. We then study the time evolution of the current in response to a slow change of the anode voltage where the same modes of oscillations appear too. The cathode current in this case is systematically advanced or retarded depending on the direction of the voltage change.
Gavrishchaka, V.V.; Ganguli, G.I.; Bakshi, P.M.; Koepke, M.E.
1998-01-01
The formalism necessary to study the collective properties of a plasma system with inhomogeneous flows is nonlocal and generally in the form of an integrodifferential equation. Usually the eigenvalue condition is reduced to a second-order differential equation for simplicity. While the gross physical behavior of the system can be obtained from the second-order differential equation level of description, higher-order corrections are necessary for greater accuracy. The limit in which the scale-size of the velocity inhomogeneity is large compared to the ion gyroradius is considered and a transverse flow profile sharply localized in space ({open_quotes}top-hat{close_quotes} profile) is assumed. In this limit, a simple analytical method for the solution of the general eigenvalue condition to all orders is developed. A comparison of the properties of the solutions obtained from the second-order differential equation level of description with those obtained from higher orders is presented. Both the resonant (dissipative) and the nonresonant (reactive) effects of velocity shear are considered. It is found that while the overall features are well represented by the second-order level of description, the higher-order corrections moderate the destabilizing effects due to velocity shear, which can be quite significant in some cases. {copyright} {ital 1998 American Institute of Physics.}
Non-Linear Characterisation of Cerebral Pressure-Flow Dynamics in Humans.
Saleem, Saqib; Teal, Paul D; Kleijn, W Bastiaan; O'Donnell, Terrence; Witter, Trevor; Tzeng, Yu-Chieh
2015-01-01
Cerebral metabolism is critically dependent on the regulation of cerebral blood flow (CBF), so it would be expected that vascular mechanisms that play a critical role in CBF regulation would be tightly conserved across individuals. However, the relationships between blood pressure (BP) and cerebral blood velocity fluctuations exhibit inter-individual variations consistent with heterogeneity in the integrity of CBF regulating systems. Here we sought to determine the nature and consistency of dynamic cerebral autoregulation (dCA) during the application of oscillatory lower body negative pressure (OLBNP). In 18 volunteers we recorded BP and middle cerebral artery blood flow velocity (MCAv) and examined the relationships between BP and MCAv fluctuations during 0.03, 0.05 and 0.07Hz OLBNP. dCA was characterised using project pursuit regression (PPR) and locally weighted scatterplot smoother (LOWESS) plots. Additionally, we proposed a piecewise regression method to statistically determine the presence of a dCA curve, which was defined as the presence of a restricted autoregulatory plateau shouldered by pressure-passive regions. Results show that LOWESS has similar explanatory power to that of PPR. However, we observed heterogeneous patterns of dynamic BP-MCAv relations with few individuals demonstrating clear evidence of a dCA central plateau. Thus, although BP explains a significant proportion of variance, dCA does not manifest as any single characteristic BP-MCAv function.
BiGlobal linear stability analysis on low-Re flow past an airfoil at high angle of attack
NASA Astrophysics Data System (ADS)
Zhang, Wei; Samtaney, Ravi
2016-04-01
We perform BiGlobal linear stability analysis on flow past a NACA0012 airfoil at 16° angle of attack and Reynolds number ranging from 400 to 1000. The steady-state two-dimensional base flows are computed using a well-tested finite difference code in combination with the selective frequency damping method. The base flow is characterized by two asymmetric recirculation bubbles downstream of the airfoil whose streamwise extent and the maximum reverse flow velocity increase with the Reynolds number. The stability analysis of the flow past the airfoil is carried out under very small spanwise wavenumber β = 10-4 to approximate the two-dimensional perturbation, and medium and large spanwise wavenumbers (β = 1-8) to account for the three-dimensional perturbation. Numerical results reveal that under small spanwise wavenumber, there are at most two oscillatory unstable modes corresponding to the near wake and far wake instabilities; the growth rate and frequency of the perturbation agree well with the two-dimensional direct numerical simulation results under all Reynolds numbers. For a larger spanwise wavenumber β = 1, there is only one oscillatory unstable mode associated with the wake instability at Re = 400 and 600, while at Re = 800 and 1000 there are two oscillatory unstable modes for the near wake and far wake instabilities, and one stationary unstable mode for the monotonically growing perturbation within the recirculation bubble via the centrifugal instability mechanism. All the unstable modes are weakened or even suppressed as the spanwise wavenumber further increases, among which the stationary mode persists until β = 4.
Technology Transfer Automated Retrieval System (TEKTRAN)
Routine DNA testing. It’s done once you’ve Marker-Assisted Breeding Pipelined promising Qantitative Trait Loci within your own breeding program and thereby established the performance-predictive power of each DNA test for your germplasm under your conditions. By then you are ready to screen your par...
NASA Technical Reports Server (NTRS)
Kantak, Anil V.
1987-01-01
Plotter routine for IBM PC (AKPLOT) designed for engineers and scientists who use graphs as integral parts of their documentation. Allows user to generate graph and edit its appearance on cathode-ray tube. Graph may undergo many interactive alterations before finally dumped from screen to be plotted by printer. Written in BASIC.
Self-organisation and non-linear dynamics in driven magnetohydrodynamic turbulent flows
NASA Astrophysics Data System (ADS)
Dallas, V.; Alexakis, A.
2015-04-01
Magnetohydrodynamic (MHD) turbulent flows driven by random, large-scale, mechanical and electromagnetic external forces of zero helicities are investigated by means of direct numerical simulations. It is shown that despite the absence of helicities in the forcing, the system is attracted to helical states of large scale condensates that exhibit laminar behaviour despite the large value of the Reynolds numbers examined. We demonstrate that the correlation time of the external forces controls the time spent on these states, i.e., for short correlation times, the system remains in the turbulent state while as the correlation time is increased, the system spends more and more time in the helical states. As a result, time averaged statistics are significantly affected by the time spent on these states. These results have important implications for MHD and turbulence theory and they provide insight into various physical phenomena where condensates transpire.
Traveling wave linear accelerator with RF power flow outside of accelerating cavities
Dolgashev, Valery A.
2016-06-28
A high power RF traveling wave accelerator structure includes a symmetric RF feed, an input matching cell coupled to the symmetric RF feed, a sequence of regular accelerating cavities coupled to the input matching cell at an input beam pipe end of the sequence, one or more waveguides parallel to and coupled to the sequence of regular accelerating cavities, an output matching cell coupled to the sequence of regular accelerating cavities at an output beam pipe end of the sequence, and output waveguide circuit or RF loads coupled to the output matching cell. Each of the regular accelerating cavities has a nose cone that cuts off field propagating into the beam pipe and therefore all power flows in a traveling wave along the structure in the waveguide.
Parametric instability of a many point-vortex system in a multi-layer flow under linear deformation
NASA Astrophysics Data System (ADS)
Ryzhov, Eugene A.; Koshel, Konstantin V.
2016-05-01
The paper deals with a dynamical system governing the motion of many point vortices located in different layers of a multi-layer flow under external deformation. The deformation consists of generally independent shear and rotational components. First, we examine the dynamics of the system's vorticity center. We demonstrate that the vorticity center of such a multi-vortex multi-layer system behaves just like the one of two point vortices interacting in a homogeneous deformation flow. Given nonstationary shear and rotational components oscillating with different magnitudes, the vorticity center may experience parametric instability leading to its unbounded growth. However, we then show that one can shift to a moving reference frame with the origin coinciding with the position of the vorticity center. In this new reference frame, the new vorticity center always stays at the origin of coordinates, and the equations governing the vortex trajectories look exactly the same as if the vorticity center had never moved in the original reference frame. Second, we studied the relative motion of two point vortices located in different layers of a two-layer flow under linear deformation. We analyze their regular and chaotic dynamics identifying parameters resulting in effective and extensive destabilization of the vortex trajectories.
De Santi, Francesca; Fraternale, Federico; Tordella, Daniela
2016-03-01
In this study we analyze the phase and group velocity of three-dimensional linear traveling waves in two sheared flows: the plane channel and the wake flows. This was carried out by varying the wave number over a large interval of values at a given Reynolds number inside the ranges 20-100, 1000-8000, for the wake and channel flow, respectively. Evidence is given about the possible presence of both dispersive and nondispersive effects which are associated with the long and short ranges of wavelength. We solved the Orr-Sommerfeld and Squire eigenvalue problem and observed the least stable mode. It is evident that, at low wave numbers, the least stable eigenmodes in the left branch of the spectrum behave in a dispersive manner. By contrast, if the wave number is above a specific threshold, a sharp dispersive-to-nondispersive transition can be observed. Beyond this transition, the dominant mode belongs to the right branch of the spectrum. The transient behavior of the phase velocity of small three-dimensional traveling waves was also considered. Having chosen the initial conditions, we then show that the shape of the transient highly depends on the transition wavelength threshold value. We show that the phase velocity can oscillate with a frequency which is equal to the frequency width of the eigenvalue spectrum. Furthermore, evidence of intermediate self-similarity is given for the perturbation field. PMID:27078456
De Santi, Francesca; Fraternale, Federico; Tordella, Daniela
2016-03-01
In this study we analyze the phase and group velocity of three-dimensional linear traveling waves in two sheared flows: the plane channel and the wake flows. This was carried out by varying the wave number over a large interval of values at a given Reynolds number inside the ranges 20-100, 1000-8000, for the wake and channel flow, respectively. Evidence is given about the possible presence of both dispersive and nondispersive effects which are associated with the long and short ranges of wavelength. We solved the Orr-Sommerfeld and Squire eigenvalue problem and observed the least stable mode. It is evident that, at low wave numbers, the least stable eigenmodes in the left branch of the spectrum behave in a dispersive manner. By contrast, if the wave number is above a specific threshold, a sharp dispersive-to-nondispersive transition can be observed. Beyond this transition, the dominant mode belongs to the right branch of the spectrum. The transient behavior of the phase velocity of small three-dimensional traveling waves was also considered. Having chosen the initial conditions, we then show that the shape of the transient highly depends on the transition wavelength threshold value. We show that the phase velocity can oscillate with a frequency which is equal to the frequency width of the eigenvalue spectrum. Furthermore, evidence of intermediate self-similarity is given for the perturbation field.
High shear rate flow in a linear stroke magnetorheological energy absorber
NASA Astrophysics Data System (ADS)
Hu, W.; Wereley, N. M.; Hiemenz, G. J.; Ngatu, G. T.
2014-05-01
To provide adaptive stroking load in the crew seats of ground vehicles to protect crew from blast or impact loads, a magnetorheological energy absorber (MREA) or shock absorber was developed. The MREA provides appropriate levels of controllable stroking load for different occupant weights and peak acceleration because the viscous stroking load generated by the MREA force increases with velocity squared, thereby reducing its controllable range at high piston velocity. Therefore, MREA behavior at high piston velocity is analyzed and validated experimentally in order to investigate the effects of velocity and magnetic field on MREA performance. The analysis used to predict the MREA force as a function of piston velocity squared and applied field is presented. A conical fairing is mounted to the piston head of the MREA in order reduce predicted inlet flow loss by 9% at nominal velocity of 8 m/s, which resulted in a viscous force reduction of nominally 4%. The MREA behavior is experimentally measured using a high speed servo-hydraulic testing system for speeds up to 8 m/s. The measured MREA force is used to validate the analysis, which captures the transient force quite accurately, although the peak force is under-predicted at the peak speed of 8 m/s.
Non-linear dynamics of annular creeping flow enclosed by an elastic membrane
NASA Astrophysics Data System (ADS)
Elbaz, Shai; Gat, Amir
2015-11-01
This study deals with the fluid-structure-interaction problem of longitudinal annular flow about a varying cross-section centre-body enclosed by an elastic membrane. The gap between the centre-body and membrane wall may be initially filled with a thin fluid layer or devoid of it. We employ elastic shell theory and the lubrication approximation and obtain a forced nonlinear diffusion equation governing the problem. In the case of an advancing liquid front in an initially unpenetrated interface (viscous peeling) the governing equation degenerates into a forced porous medium equation, for which several closed-form solutions can be obtained. Based on self-similarity we define propagation laws for the fluid-elastic interaction which in turn provide the basis for numerical investigation of compound solutions such as pulse trains and other waveforms. The presented interaction between viscosity and elasticity may be applied to fields such as soft-robotics and micro-scale or larger swimmers by allowing for the time-dependent control of a compliant boundary.
Linear impact of thermal inhomogeneities on mesoscale atmospheric flow with zero synoptic wind
NASA Technical Reports Server (NTRS)
Dalu, G. A.; Pielke, R. A.; Avissar, R.; Kallos, G.; Baldi, M.; Guerrini, A.
1991-01-01
An analytical evaluation of the perturbations to mesoscale atmospheric flows induced by thermal inhomogeneities in the convective boundary layer is presented. The time evolution of these perturbations as a function of the intensity and of the horizontal and vertical scales of the diabatic forcing is studied. The problem is approached using Laplace transform theory for the time behavior and Green function theory for the spatial structure. Results show that the growth of the atmospheric perturbations closely follows the growth of the convective boundary layer; the transient being characterized by a number of inertia-gravity oscillations of decreasing intensity. The vertical scale is determined by the depth of the convective boundary layer; and the horizontal scale is determined by the local Rossby deformation radius. Sinusoidally periodic thermal forcing induce periodic atmospheric cells of the same horizontal scale. The intensity of mesoscale cells increases for increasing values of the wave number, reaches its maximum value when the wavelength of the forcing is of the order of the local Rossby radius, and then decreases as the wavelength of the forcing decreases.
Chen, R.; Xie, J. L. Yu, C. X.; Liu, A. D.; Lan, T.; Li, H.; Liu, W. D.; Zhang, S. B.; Kong, D. F.; Hu, G. H.
2015-01-15
Low-frequency zonal flow (ZF) has been observed in a linear magnetic plasma device, exhibiting significant intermittency. Using the conditional analysis method, a time-averaged fluctuation-induced particle flux was observed to consistently decrease as ZF increased in amplitude. A dominant fraction of the flux, which is driven by drift-wave harmonics, is reversely modulated by ZF in the time domain. Spectra of the flux, together with each of the related turbulence properties, are estimated subject to two conditions, i.e., when potential fluctuation series represents a strong ZF intermittency or a very weak ZF component. Comparison of frequency-domain results demonstrates that ZF reduces the cross-field particle transport primarily by suppressing the density fluctuation as well as decorrelating density and potential fluctuations.
Lefkoff, L.J.; Gorelick, S.M.
1987-01-01
A FORTRAN-77 computer program code that helps solve a variety of aquifer management problems involving the control of groundwater hydraulics. It is intended for use with any standard mathematical programming package that uses Mathematical Programming System input format. The computer program creates the input files to be used by the optimization program. These files contain all the hydrologic information and management objectives needed to solve the management problem. Used in conjunction with a mathematical programming code, the computer program identifies the pumping or recharge strategy that achieves a user 's management objective while maintaining groundwater hydraulic conditions within desired limits. The objective may be linear or quadratic, and may involve the minimization of pumping and recharge rates or of variable pumping costs. The problem may contain constraints on groundwater heads, gradients, and velocities for a complex, transient hydrologic system. Linear superposition of solutions to the transient, two-dimensional groundwater flow equation is used by the computer program in conjunction with the response matrix optimization method. A unit stress is applied at each decision well and transient responses at all control locations are computed using a modified version of the U.S. Geological Survey two dimensional aquifer simulation model. The program also computes discounted cost coefficients for the objective function and accounts for transient aquifer conditions. (Author 's abstract)
Saloranta, Tuomo M; Andersen, Tom; Naes, Kristoffer
2006-01-01
Rate constant bioaccumulation models are applied to simulate the flow of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in the coastal marine food web of Frierfjorden, a contaminated fjord in southern Norway. We apply two different ways to parameterize the rate constants in the model, global sensitivity analysis of the models using Extended Fourier Amplitude Sensitivity Test (Extended FAST) method, as well as results from general linear system theory, in order to obtain a more thorough insight to the system's behavior and to the flow pathways of the PCDD/Fs. We calibrate our models against observed body concentrations of PCDD/Fs in the food web of Frierfjorden. Differences between the predictions from the two models (using the same forcing and parameter values) are of the same magnitude as their individual deviations from observations, and the models can be said to perform about equally well in our case. Sensitivity analysis indicates that the success or failure of the models in predicting the PCDD/F concentrations in the food web organisms highly depends on the adequate estimation of the truly dissolved concentrations in water and sediment pore water. We discuss the pros and cons of such models in understanding and estimating the present and future concentrations and bioaccumulation of persistent organic pollutants in aquatic food webs.
NASA Astrophysics Data System (ADS)
Rosén, T.; Do-Quang, M.; Aidun, C. K.; Lundell, F.
2015-05-01
This work describes the inertial effects on the rotational behavior of an oblate spheroidal particle confined between two parallel opposite moving walls, which generate a linear shear flow. Numerical results are obtained using the lattice Boltzmann method with an external boundary force. The rotation of the particle depends on the particle Reynolds number, Rep=G d2ν-1 (G is the shear rate, d is the particle diameter, ν is the kinematic viscosity), and the Stokes number, St =α Rep (α is the solid-to-fluid density ratio), which are dimensionless quantities connected to fluid and particle inertia, respectively. The results show that two inertial effects give rise to different stable rotational states. For a neutrally buoyant particle (St =Rep ) at low Rep, particle inertia was found to dominate, eventually leading to a rotation about the particle's symmetry axis. The symmetry axis is in this case parallel to the vorticity direction; a rotational state called log-rolling. At high Rep, fluid inertia will dominate and the particle will remain in a steady state, where the particle symmetry axis is perpendicular to the vorticity direction and has a constant angle ϕc to the flow direction. The sequence of transitions between these dynamical states were found to be dependent on density ratio α , particle aspect ratio rp, and domain size. More specifically, the present study reveals that an inclined rolling state (particle rotates around its symmetry axis, which is not aligned in the vorticity direction) appears through a pitchfork bifurcation due to the influence of periodic boundary conditions when simulated in a small domain. Furthermore, it is also found that a tumbling motion, where the particle symmetry axis rotates in the flow-gradient plane, can be a stable motion for particles with high rp and low α .
Rosén, T; Do-Quang, M; Aidun, C K; Lundell, F
2015-05-01
This work describes the inertial effects on the rotational behavior of an oblate spheroidal particle confined between two parallel opposite moving walls, which generate a linear shear flow. Numerical results are obtained using the lattice Boltzmann method with an external boundary force. The rotation of the particle depends on the particle Reynolds number, Re(p)=Gd(2)ν(-1) (G is the shear rate, d is the particle diameter, ν is the kinematic viscosity), and the Stokes number, St=αRe(p) (α is the solid-to-fluid density ratio), which are dimensionless quantities connected to fluid and particle inertia, respectively. The results show that two inertial effects give rise to different stable rotational states. For a neutrally buoyant particle (St=Re(p)) at low Re(p), particle inertia was found to dominate, eventually leading to a rotation about the particle's symmetry axis. The symmetry axis is in this case parallel to the vorticity direction; a rotational state called log-rolling. At high Re(p), fluid inertia will dominate and the particle will remain in a steady state, where the particle symmetry axis is perpendicular to the vorticity direction and has a constant angle ϕ(c) to the flow direction. The sequence of transitions between these dynamical states were found to be dependent on density ratio α, particle aspect ratio r(p), and domain size. More specifically, the present study reveals that an inclined rolling state (particle rotates around its symmetry axis, which is not aligned in the vorticity direction) appears through a pitchfork bifurcation due to the influence of periodic boundary conditions when simulated in a small domain. Furthermore, it is also found that a tumbling motion, where the particle symmetry axis rotates in the flow-gradient plane, can be a stable motion for particles with high r(p) and low α.
Routine vaccination against chickenpox?
2012-04-01
Varicella-zoster virus (VZV) causes both varicella and herpes zoster. In 1995 a varicella vaccine was licensed in the USA and was incorporated into the routine vaccination programme for children; a decline of varicella among children and adults, and a reduction in associated hospitalisation, complications and mortality, has resulted. In the UK, a policy of targeted vaccination of at-risk groups has been in place since the vaccine was introduced. Here we review the evidence for the different approaches to VZV vaccination policy.
NASA Technical Reports Server (NTRS)
Lawson, C. L.; Krogh, F. T.; Gold, S. S.; Kincaid, D. R.; Sullivan, J.; Williams, E.; Hanson, R. J.; Haskell, K.; Dongarra, J.; Moler, C. B.
1982-01-01
The Basic Linear Algebra Subprograms (BLAS) library is a collection of 38 FORTRAN-callable routines for performing basic operations of numerical linear algebra. BLAS library is portable and efficient source of basic operations for designers of programs involving linear algebriac computations. BLAS library is supplied in portable FORTRAN and Assembler code versions for IBM 370, UNIVAC 1100 and CDC 6000 series computers.
Examination of the Circle Spline Routine
NASA Technical Reports Server (NTRS)
Dolin, R. M.; Jaeger, D. L.
1985-01-01
The Circle Spline routine is currently being used for generating both two and three dimensional spline curves. It was developed for use in ESCHER, a mesh generating routine written to provide a computationally simple and efficient method for building meshes along curved surfaces. Circle Spline is a parametric linear blending spline. Because many computerized machining operations involve circular shapes, the Circle Spline is well suited for both the design and manufacturing processes and shows promise as an alternative to the spline methods currently supported by the Initial Graphics Specification (IGES).
NASA Technical Reports Server (NTRS)
Carlson, Harry W.; Darden, Christine M.
1987-01-01
Low-speed experimental force and data on a series of thin swept wings with sharp leading edges and leading and trailing-edge flaps are compared with predictions made using a linearized-theory method which includes estimates of vortex forces. These comparisons were made to assess the effectiveness of linearized-theory methods for use in the design and analysis of flap systems in subsonic flow. Results demonstrate that linearized-theory, attached-flow methods (with approximate representation of vortex forces) can form the basis of a rational system for flap design and analysis. Even attached-flow methods that do not take vortex forces into account can be used for the selection of optimized flap-system geometry, but design-point performance levels tend to be underestimated unless vortex forces are included. Illustrative examples of the use of these methods in the design of efficient low-speed flap systems are included.
Linear stability of a gas boundary layer flowing past a thin liquid film over a flat plate
NASA Astrophysics Data System (ADS)
Pelekasis, Nikolaos A.; Tsamopoulos, John A.
2001-06-01
The flow of a gas stream past a flat plate under the influence of rainfall is investigated. As raindrops sediment on the flat plate, they coalesce to form a water film that flows under the action of shear from the surrounding gas stream. In the limit of (a) large Reynolds number, Re, in the gas phase, (b) small rainfall rate, r[dot above], compared to the free-stream velocity, U[infty infinity], and (c) small film thickness compared to the thickness of the boundary layer that surrounds it, a similarity solution is obtained that predicts growth of the liquid film like x3/4; x denotes dimensionless distance from the leading edge. The flow in the gas stream closely resembles the Blasius solution, whereas viscous dissipation dominates inside the film. Local linear stability analysis is performed, assuming nearly parallel base flow in the two streams, and operating in the triple-deck regime. Two distinct families of eigenvalues are identified, one corresponding to the well-known Tollmien Schlichting (TS) waves that originate in the gas stream, and the other corresponding to an interfacial instability. It is shown that, for the air water system, the TS waves are convectively unstable whereas the interfacial waves exhibit a pocket of absolute instability, at the streamwise location of the applied disturbance. Moreover, it is found that as the inverse Weber number (We[minus sign]1) increases, indicating the increasing effect of surface tension compared to inertia, the pocket of absolute instability is translated towards larger distances from the leading edge and the growth rate of unstable waves decreases, until a critical value is reached, We[minus sign]1 [approximate] We[minus sign]1c, beyond which the family of interfacial waves becomes convectively unstable. Increasing the inverse Froude number (Fr[minus sign]1), indicating the increasing effect of gravity compared to inertia, results in the pocket of absolute instability shrinking until a critical value is reached, Fr
NASA Astrophysics Data System (ADS)
Xiong, Y. P.; Xing, J. T.; Price, W. G.
2003-10-01
Generalized integrated structure-control dynamical systems consisting of any number of active/passive controllers and three-dimensional rigid/flexible substructures are investigated. The developed mathematical model assessing the behaviour of these complex systems includes description of general boundary conditions, the interaction mechanisms between structures, power flows and control characteristics. Three active control strategies are examined. That is, multiple channel absolute/relative velocity feedback controllers, their hybrid combination and an existing passive control system to which the former control systems are attached in order to improve overall control efficiency. From the viewpoint of continuum mechanics, an analytical solution of this generalized structure-control system has been developed allowing predictions of the dynamic responses at any point on or in substructures of the coupled system. Absolute or relative dynamic response or receptance, transmissibility, mobility, transfer functions have been derived to evaluate complex dynamic interaction mechanisms through various transmission paths. The instantaneous and time-averaged power flow of energy input, transmission and dissipation or absorption within and between the source substructure, control subsystems and controlled substructure are presented. The general theory developed provides an integrated framework to solve various vibration isolation and control problems and provides a basis to develop a general algorithm that may allow the user to build arbitrarily complex linear control models using simple commands and inputs. The proposed approach is applied to a practical example to illustrate and validate the mathematical model as well as to assess control effectiveness and to provide important guidelines to assist vibration control designers.
NASA Astrophysics Data System (ADS)
Frehner, Marcel; Amschwand, Dominik; Gärtner-Roer, Isabelle
2016-04-01
Rockglaciers consist of unconsolidated rock fragments (silt/sand-rock boulders) with interstitial ice; hence their creep behavior (i.e., rheology) may deviate from the simple and well-known flow-laws for pure ice. Here we constrain the non-linear viscous flow law that governs rockglacier creep based on geomorphological observations. We use the Murtèl rockglacier (upper Engadin valley, SE Switzerland) as a case study, for which high-resolution digital elevation models (DEM), time-lapse borehole deformation data, and geophysical soundings exist that reveal the exterior and interior architecture and dynamics of the landform. Rockglaciers often feature a prominent furrow-and-ridge topography. For the Murtèl rockglacier, Frehner et al. (2015) reproduced the wavelength, amplitude, and distribution of the furrow-and-ridge morphology using a linear viscous (Newtonian) flow model. Arenson et al. (2002) presented borehole deformation data, which highlight the basal shear zone at about 30 m depth and a curved deformation profile above the shear zone. Similarly, the furrow-and-ridge morphology also exhibits a curved geometry in map view. Hence, the surface morphology and the borehole deformation data together describe a curved 3D geometry, which is close to, but not quite parabolic. We use a high-resolution DEM to quantify the curved geometry of the Murtèl furrow-and-ridge morphology. We then calculate theoretical 3D flow geometries using different non-linear viscous flow laws. By comparing them to the measured curved 3D geometry (i.e., both surface morphology and borehole deformation data), we can determine the most adequate flow-law that fits the natural data best. Linear viscous models result in perfectly parabolic flow geometries; non-linear creep leads to localized deformation at the sides and bottom of the rockglacier while the deformation in the interior and top are less intense. In other words, non-linear creep results in non-parabolic flow geometries. Both the
NASA Technical Reports Server (NTRS)
Carlson, John R.
1996-01-01
The ability of the three-dimensional Navier-Stokes method, PAB3D, to simulate the effect of Reynolds number variation using non-linear explicit algebraic Reynolds stress turbulence modeling was assessed. Subsonic flat plate boundary-layer flow parameters such as normalized velocity distributions, local and average skin friction, and shape factor were compared with DNS calculations and classical theory at various local Reynolds numbers up to 180 million. Additionally, surface pressure coefficient distributions and integrated drag predictions on an axisymmetric nozzle afterbody were compared with experimental data from 10 to 130 million Reynolds number. The high Reynolds data was obtained from the NASA Langley 0.3m Transonic Cryogenic Tunnel. There was generally good agreement of surface static pressure coefficients between the CFD and measurement. The change in pressure coefficient distributions with varying Reynolds number was similar to the experimental data trends, though slightly over-predicting the effect. The computational sensitivity of viscous modeling and turbulence modeling are shown. Integrated afterbody pressure drag was typically slightly lower than the experimental data. The change in afterbody pressure drag with Reynolds number was small both experimentally and computationally, even though the shape of the distribution was somewhat modified with Reynolds number.
NASA Astrophysics Data System (ADS)
Kerem Uguz, A.; Aubry, Nadine
2007-11-01
The instability of a flat interface between two viscous, immiscible and incompressible liquids in plane Poiseuille flow is studied in the presence of an electric field parallel to the flat interface. In practice, either the stability or instability of the interface is desired depending on the application such as material deposition, mixing, or droplet formation. For that purpose the effect of various parameters was studied via linear stability analysis. The electric field was found to be either stabilizing or destabilizing depending on the electrical properties of the fluids. An interesting feature of this problem is the presence of a second window of stability, namely for some parameters there exist two regions of wavenumbers in which the system is stable. Our results are compared with the case where the electric field is normal to the fluid-fluid interface [1, 2]. [1] O. Ozen, N. Aubry, D. T. Papageorgiou and P. G. Petropoulos, Electrochimica Acta, 51, 5316-5323 (2006) [2] F. Li, O. Ozen, N. Aubry, D.T. Papageorgiou and P.G. Petropoulos, Journal of Fluid Mechanics, 583, 347-377 (2007)
Lidar Altitude Data Read Routine
Atmospheric Science Data Center
2013-03-19
Lidar Altitude Data Read Routine This routine demonstrates reading the lidar altitude data stored in CALIPSO Lidar Level 1B Profile, Level 2 Aerosol ... Data Language (IDL) and uses HDF routine calls to read the altitude data which are stored in an HDF vdata (table) structure, as described ...
NASA Astrophysics Data System (ADS)
Satija, Aaditya; Caers, Jef
2015-03-01
Inverse modeling is widely used to assist with forecasting problems in the subsurface. However, full inverse modeling can be time-consuming requiring iteration over a high dimensional parameter space with computationally expensive forward models and complex spatial priors. In this paper, we investigate a prediction-focused approach (PFA) that aims at building a statistical relationship between data variables and forecast variables, avoiding the inversion of model parameters altogether. The statistical relationship is built by first applying the forward model related to the data variables and the forward model related to the prediction variables on a limited set of spatial prior models realizations, typically generated through geostatistical methods. The relationship observed between data and prediction is highly non-linear for many forecasting problems in the subsurface. In this paper we propose a Canonical Functional Component Analysis (CFCA) to map the data and forecast variables into a low-dimensional space where, if successful, the relationship is linear. CFCA consists of (1) functional principal component analysis (FPCA) for dimension reduction of time-series data and (2) canonical correlation analysis (CCA); the latter aiming to establish a linear relationship between data and forecast components. If such mapping is successful, then we illustrate with several cases that (1) simple regression techniques with a multi-Gaussian framework can be used to directly quantify uncertainty on the forecast without any model inversion and that (2) such uncertainty is a good approximation of uncertainty obtained from full posterior sampling with rejection sampling.
Adjoint-based estimation of plate coupling in a non-linear mantle flow model: theory and examples
NASA Astrophysics Data System (ADS)
Ratnaswamy, Vishagan; Stadler, Georg; Gurnis, Michael
2015-08-01
We develop and validate a systematic approach to infer plate boundary strength and rheological parameters in models of mantle flow from surface velocity observations. Based on a realistic rheological model that includes yielding and strain rate weakening from dislocation creep, we formulate the inverse problem in a Bayesian inference framework. To study the distribution of parameters that are consistent with the observations, we compute the maximum a posteriori (MAP) point, Gaussian approximations of the parameter distribution around that MAP point, and employ Markov Chain Monte Carlo (MCMC) sampling methods. The computation of the MAP point and the Gaussian approximation require first and second derivatives of an objective function subject to non-linear Stokes equations; these derivatives are computed efficiently using adjoint Stokes equations. We set up 2-D numerical experiments with many of the elements expected in a global geophysical inversion. This setup incorporates three subduction zones with slab and weak zone (interplate fault) geometry consistent with average seismic characteristics. With these experiments, we demonstrate that when the temperature field is known, we can recover the strength of plate boundaries, the yield stress and strain rate exponent in the upper mantle. When the number of uncertain parameters increases, there are trade-offs between the inferred parameters. These trade-offs depend on how well the observational data represents the surface velocities, and on the weakness of plate boundaries. As the plate boundary coupling drops below a threshold, the uncertainty of the inferred parameters increases due to insensitivity of plate motion to plate coupling. Comparing the trade-offs between inferred rheological parameters found from the Gaussian approximation of the parameter distribution and from MCMC sampling, we conclude that the Gaussian approximation-which is significantly cheaper to compute-is often a good approximation, in particular
Cosmic flows and the expansion of the local Universe from non-linear phase-space reconstructions
NASA Astrophysics Data System (ADS)
Heß, Steffen; Kitaura, Francisco-Shu
2016-03-01
In this work, we investigate the impact of cosmic flows and density perturbations on Hubble constant H0 measurements using non-linear phase-space reconstructions of the Local Universe (LU). In particular, we rely on a set of 25 precise constrained N-body simulations based on Bayesian initial conditions reconstructions of the LU using the Two-Micron Redshift Survey galaxy sample within distances of about 90 h-1 Mpc. These have been randomly extended up to volumes enclosing distances of 360 h-1 Mpc with augmented Lagrangian perturbation theory (750 simulations in total), accounting in this way for gravitational mode coupling from larger scales, correcting for periodic boundary effects, and estimating systematics of missing attractors (σlarge = 134 s-1 km). We report on Local Group (LG) speed reconstructions, which for the first time are compatible with those derived from cosmic microwave background-dipole measurements: |vLG| = 685 ± 137 s-1 km. The direction (l, b) = (260.5° ± 13.3°, 39.1 ± 10.4°) is found to be compatible with the observations after considering the variance of large scales. Considering this effect of large scales, our local bulk flow estimations assuming a Λ cold dark matter model are compatible with the most recent estimates based on velocity data derived from the Tully-Fisher relation. We focus on low-redshift supernova measurements out to 0.01 < z < 0.025, which have been found to disagree with probes at larger distances. Our analysis indicates that there are two effects related to cosmic variance contributing to this tension. The first one is caused by the anisotropic distribution of supernovae, which aligns with the velocity dipole and hence induces a systematic boost in H0. The second one is due to the inhomogeneous matter fluctuations in the LU. In particular, a divergent region surrounding the Virgo Supercluster is responsible for an additional positive bias in H0. Taking these effects into account yields a correction of ΔH0 = -1
Modular thermal analyzer routine, volume 1
NASA Technical Reports Server (NTRS)
Oren, J. A.; Phillips, M. A.; Williams, D. R.
1972-01-01
The Modular Thermal Analyzer Routine (MOTAR) is a general thermal analysis routine with strong capabilities for performing thermal analysis of systems containing flowing fluids, fluid system controls (valves, heat exchangers, etc.), life support systems, and thermal radiation situations. Its modular organization permits the analysis of a very wide range of thermal problems for simple problems containing a few conduction nodes to those containing complicated flow and radiation analysis with each problem type being analyzed with peak computational efficiency and maximum ease of use. The organization and programming methods applied to MOTAR achieved a high degree of computer utilization efficiency in terms of computer execution time and storage space required for a given problem. The computer time required to perform a given problem on MOTAR is approximately 40 to 50 percent that required for the currently existing widely used routines. The computer storage requirement for MOTAR is approximately 25 percent more than the most commonly used routines for the most simple problems but the data storage techniques for the more complicated options should save a considerable amount of space.
NASA Astrophysics Data System (ADS)
Akimoto, Hiromichi; Hara, Yutaka; Kawamura, Takafumi; Nakamura, Takuju; Lee, Yeon-Seung
2013-12-01
In a vertical axis wind turbine (VAWT), turbine blades are subjected to the curved flow field caused by the revolution of turbine. However, performance prediction of VAWT is usually based on the fluid dynamic coefficients obtained in wind tunnel measurements of the two-dimensional static wing. The difference of fluid dynamic coefficients in the curved flow and straight flow deteriorates the accuracy of performance prediction. To find the correlation between the two conditions of curved and straight flow, the authors propose a conformal mapping method on complex plane. It provides bidirectional mapping between the two flow fields. For example, the flow around a symmetric wing in the curved flow is mapped to that around a curved (cambered) wing in the straight flow. Although the shape of mapped wing section is different from the original one, its aerodynamic coefficients show a good correlation to those of the original in the rotating condition. With the proposed method, we can reproduce the local flow field around a rotating blade from the flow data around the mapped static wing in the straight flow condition.
NASA Astrophysics Data System (ADS)
Karapetsas, George; Tsamopoulos, John
2013-09-01
During extrusion of viscoelastic fluids various flow instabilities may arise resulting in a distorted free surface. In order to investigate the factors generating these instabilities we performed a linear stability analysis at zero Reynolds number around the steady solution of the cylindrical or planar stick-slip flow for a viscoelastic fluid following the affine exponential Phan-Thien Tanner (PTT) model. Stick-slip flow is an important special case of the extrudate swell problem, since the latter reduces to it in the limit of infinite surface tension but avoids the complications of a free-boundary flow. The linear stability analysis is performed for various values of the rheological parameters of the PTT model in order to determine the effects of all material properties. It is found that the flow becomes unstable as the Weissenberg number increases above a critical value, due to a Hopf bifurcation suggesting that the flow will become periodic in time. Both the critical value of the Weissenberg number and the frequency of the instability depend strongly on the rheological parameters of the viscoelastic model. The corresponding eigenvectors indicate that the perturbed flow field has a spatially periodic structure, initiated at the rim of the die, extending for up to 5-7 die gaps downstream, but confined close to the surface of the extrudate, in qualitative agreement with existing experiments. This suggests that instability is generated by the combination of the singularity in the velocity and stress fields at the die lip and the strong extension that the extruded polymer undergoes near its surface. The elasticity alone can be responsible for the appearance of instabilities in the extrusion process of viscoelastic fluids and the often used assumptions of wall slip or compressibility, although they might be present, are not required. Finally, the mechanisms that produce these instabilities are examined through energy analysis of the disturbance flow.
Yonekura, Y.; Nishizawa, S.; Mukai, T.; Fujita, T.; Fukuyama, H.; Ishikawa, M.; Kikuchi, H.; Konishi, J.; Andersen, A.R.; Lassen, N.A.
1988-12-01
In order to validate the use of technetium-99m-d,l-hexamethylpropyleneamine oxime (HM-PAO) as a flow tracer, a total of 21 cases were studied with single photon emission computerized tomography (SPECT), and compared to regional cerebral blood flow (rCBF) measured by position emission tomography (PET) using the oxygen-15 CO2 inhalation technique. Although HM-PAO SPECT and rCBF PET images showed a similar distribution pattern the HM-PAO SPECT image showed less contrast between high and low activity flow regions than the rCBF image and a nonlinear relationship between HM-PAO activity and rCBF was shown. Based on the assumption of flow-dependent backdiffusion of HM-PAO from the brain, we applied a linearization algorithm to correct the HM-PAO SPECT images. The corrected HM-PAO SPECT images revealed a good linear correlation with rCBF (r = 0.901, p less than 0.001). The results indicated HM-PAO can be used as a flow tracer with SPECT after proper correction.
NASA Astrophysics Data System (ADS)
Zillinger, Christian
2016-09-01
In a previous article (Zillinger, Linear inviscid damping for monotone shear flows, 2014), we have established linear inviscid damping for a large class of monotone shear flows in a finite periodic channel and have further shown that boundary effects asymptotically lead to the formation of singularities of derivatives of the solution as {t → infty}. As the main results of this article, we provide a detailed description of the singularity formation and establish stability in all sub-critical fractional Sobolev spaces and blow-up in all super-critical spaces. Furthermore, we discuss the implications of the blow-up to the problem of nonlinear inviscid damping in a finite periodic channel, where high regularity would be essential to control nonlinear effects.
NASA Astrophysics Data System (ADS)
Dagostino, Luca
1987-05-01
This theses presents the design, development and operations of a Cavitation Susceptibility Meter based on the use of a venturi tube for the measurement of the content of active cavitation nuclei in water samples. The pressure at the venturi throat is determined from the upstream pressure and the local flow velocity without corrections for viscous effects because the flow possesses a laminar potential core in all operational conditions. The detection ov cavitation and the measurement of the flow velocity are carried out optically. The apparatus comprises a Laser Doppler Velocimeter for the measurement of the flow velocity and the detection of cavitation, a custom-made electronic Signal Processor for real time generation and temporary storage of the data and a computerized system for the final acquisition and reduction of the collected data. The results of application of the Cavitation Susceptibility Meter to the measurement of the water quality of the tap water samples are presented. The results of an investigation are presented on the linearized dynamics of two-phase bubbly flows with the inclusion of bubble dynamics effects. Two flow configurations have been studied: the time dependent one-dimensional flow of a spherical bubble cloud subject to harmonic excitation of the far field external pressure and the steady state two-dimensional flow of a bubbly mixture on a slender profile of arbitrary shape.
Massively Parallel Linear Stability Analysis with P_ARPACK for 3D Fluid Flow Modeled with MPSalsa
Lehoucq, R.B.; Salinger, A.G.
1998-10-13
We are interested in the stability of three-dimensional fluid flows to small dkturbances. One computational approach is to solve a sequence of large sparse generalized eigenvalue problems for the leading modes that arise from discretizating the differential equations modeling the flow. The modes of interest are the eigenvalues of largest real part and their associated eigenvectors. We discuss our work to develop an effi- cient and reliable eigensolver for use by the massively parallel simulation code MPSalsa. MPSalsa allows simulation of complex 3D fluid flow, heat transfer, and mass transfer with detailed bulk fluid and surface chemical reaction kinetics.
NASA Astrophysics Data System (ADS)
Harman, Ian N.; Finnigan, John J.
2013-04-01
We revisit the analytical model for atmospheric boundary-layer flow over a hill covered with a canopy of Finnigan and Belcher (Q J R Meteorol Soc 130:1-29, 2004). Remaining within the overall scope of that analysis we extend in two ways. First we include the impacts of the advection terms within the upper canopy in a simple, but approximate, manner. Second we establish a modification for the associated pressure perturbation. Both extensions allow us to extend the parameter range wherein the analytical framework can be expected to reasonably hold. The within-canopy advection terms act to provide a downstream shift, and decreased magnitude, to the flow perturbations within the canopy as compared to the predictions from the original analysis. Through continuity, similar, but smaller, impacts are seen above the canopy. Together these act to reduce the differences in the streamwise positions of the topographic speed-up seen above and within the canopy. The modified pressure perturbation also acts to decrease the magnitude of the flow perturbations. The predicted topographic influence on the flow is reduced from that given in the original analysis but, importantly, the positions where the topographic influences most strongly affect the flow, and by extension the scalar concentration fields, are also changed. Predictions from the revised analysis are shown to be in good agreement with wind-tunnel data for flow over an isolated narrow ridge covered by a partially dense canopy.
NASA Astrophysics Data System (ADS)
Mahanthesh, B.; Gireesha, B. J.; Gorla, R. S. Reddy; Abbasi, F. M.; Shehzad, S. A.
2016-11-01
Numerical solutions of three-dimensional flow over a non-linear stretching surface are developed in this article. An electrically conducting flow of viscous nanoliquid is considered. Heat transfer phenomenon is accounted under thermal radiation, Joule heating and viscous dissipation effects. We considered the variable heat flux condition at the surface of sheet. The governing mathematical equations are reduced to nonlinear ordinary differential systems through suitable dimensionless variables. A well-known shooting technique is implemented to obtain the results of dimensionless velocities and temperature. The obtained results are plotted for multiple values of pertinent parameters to discuss the salient features of these parameters on fluid velocity and temperature. The expressions of skin-friction coefficient and Nusselt number are computed and analyzed comprehensively through numerical values. A comparison of present results with the previous results in absence of nanoparticle volume fraction, mixed convection and magnetic field is computed and an excellent agreement noticed. We also computed the results for both linear and non-linear stretching sheet cases.
On the effect of a non-uniform longitudinal ion flow on the linear ITG mode stability.
NASA Astrophysics Data System (ADS)
Lontano, Maurizio; Lazzaro, Enzo; Varischetti, Maria Cecilia
2006-10-01
A one-dimensional model for slab ion temperature gradient (ITG) modes, in the presence of an inhomogeneous equilibrium plasma velocity along the main magnetic field direction, has been formulated in the frame of a two-fluid guiding-center approximation. The physical effects of a magnetic field gradient and of the line curvature are included by means of a gravitational drift velocity. The magnetic shear across the plasma slab is also taken into account. The linear stability of slow plasma dynamics, under the assumptions of quasi-neutrality and adiabatic electrons, is described by means of a third-degree dispersion relation. Generally speaking, the presence of a sheared longitudinal ion velocity leads to the linear destabilization of the ITG modes, especially for flat equilibrium density profiles. Transverse quasi-linear fluxes of ion thermal energy and longitudinal momentum are calculated for different equilibrium profiles of the density, temperature, momentum, and magnetic shear. Plasma configurations leading to zero transverse (or even negative) momentum fluxes are exploited and discussed in the light of their experimental implementation.
NASA Astrophysics Data System (ADS)
Beljadid, Abdelaziz; Mohammadian, Abdolmajid; Qiblawey, Hazim
2016-10-01
The discretization of the shallow water system on unstructured grids can lead to spurious modes which usually can affect accuracy and/or cause stability problems. This paper introduces a new approach for stability analysis of unstructured linear finite volume schemes for linear shallow water equations with the Coriolis Effect using spectra, pseudospectra, and singular value decomposition. The discrete operator of the scheme is the principal parameter used in the analysis. It is shown that unstructured grids have a large influence on operator normality. In some cases the eigenvectors of the operator can be far from orthogonal, which leads to amplification of solutions and/or stability problems. Large amplifications of the solution can be observed, even for discrete operators which respect the condition of asymptotic stability, and in some cases even for Lax-Richtmyer stable methods. The pseudospectra are shown to be efficient for the verification of stability of finite volume methods for linear shallow water equations. In some cases, the singular value decomposition is employed for further analysis in order to provide more information about the existence of unstable modes. The results of the analysis can be helpful in choosing the type of mesh, the appropriate placements of the variables of the system on the grid, and the suitable discretization method which is stable for a wide range of modes.
NASA Technical Reports Server (NTRS)
Arneson, Heather M.; Dousse, Nicholas; Langbort, Cedric
2014-01-01
We consider control design for positive compartmental systems in which each compartment's outflow rate is described by a concave function of the amount of material in the compartment.We address the problem of determining the routing of material between compartments to satisfy time-varying state constraints while ensuring that material reaches its intended destination over a finite time horizon. We give sufficient conditions for the existence of a time-varying state-dependent routing strategy which ensures that the closed-loop system satisfies basic network properties of positivity, conservation and interconnection while ensuring that capacity constraints are satisfied, when possible, or adjusted if a solution cannot be found. These conditions are formulated as a linear programming problem. Instances of this linear programming problem can be solved iteratively to generate a solution to the finite horizon routing problem. Results are given for the application of this control design method to an example problem. Key words: linear programming; control of networks; positive systems; controller constraints and structure.
Hodgkins, Richard; Cooper, Richard; Tranter, Martyn; Wadham, Jemma
2013-01-01
[1] The drainage systems of polythermal glaciers play an important role in high-latitude hydrology, and are determinants of ice flow rate. Flow-recession analysis and linear-reservoir simulation of runoff time series are here used to evaluate seasonal and inter-annual variability in the drainage system of the polythermal Finsterwalderbreen, Svalbard, in 1999 and 2000. Linear-flow recessions are pervasive, with mean coefficients of a fast reservoir varying from 16 (1999) to 41 h (2000), and mean coefficients of an intermittent, slow reservoir varying from 54 (1999) to 114 h (2000). Drainage-system efficiency is greater overall in the first of the two seasons, the simplest explanation of which is more rapid depletion of the snow cover. Reservoir coefficients generally decline during each season (at 0.22 h d−1 in 1999 and 0.52 h d−1 in 2000), denoting an increase in drainage efficiency. However, coefficients do not exhibit a consistent relationship with discharge. Finsterwalderbreen therefore appears to behave as an intermediate case between temperate glaciers and other polythermal glaciers with smaller proportions of temperate ice. Linear-reservoir runoff simulations exhibit limited sensitivity to a relatively wide range of reservoir coefficients, although the use of fixed coefficients in a spatially lumped model can generate significant subseasonal error. At Finsterwalderbreen, an ice-marginal channel with the characteristics of a fast reservoir, and a subglacial upwelling with the characteristics of a slow reservoir, both route meltwater to the terminus. This suggests that drainage-system components of significantly contrasting efficiencies can coexist spatially and temporally at polythermal glaciers. PMID:25598557
NASA Astrophysics Data System (ADS)
Blokhin, Alexander; Tkachev, Dmitry
2016-10-01
We study the classical problem for a flow of stationary inviscid non-heat-conducting gas in thermodynamical equilibrium moving onto a planar infinite wedge. Under the fulfillment of the Lopatinski condition on the shock (neutral stability) the correctness of the linearized mixed problem (main solution is a weak shock) is proven and the representation of the classical solution is obtained and in that case (unlike the case of a uniform Lopatinski condition i.e. absolutely stable attached shock) there are additionally plane waves in representation. For finite initial data solution goes to prescribed regime given infinite time.
Chen, R; Hahn, C E W; Farmery, A D
2012-08-15
The development of a methodology for testing the time response, linearity and performance characteristics of ultra fast fibre optic oxygen sensors in the liquid phase is presented. Two standard medical paediatric oxygenators are arranged to provide two independent extracorporeal circuits. Flow from either circuit can be diverted over the sensor under test by means of a system of rapid cross-over solenoid valves exposing the sensor to an abrupt change in oxygen partial pressure, P O2. The system is also capable of testing the oxygen sensor responses to changes in temperature, carbon dioxide partial pressure P CO2 and pH in situ. Results are presented for a miniature fibre optic oxygen sensor constructed in-house with a response time ≈ 50 ms and a commercial fibre optic sensor (Ocean Optics Foxy), when tested in flowing saline and stored blood.
NASA Technical Reports Server (NTRS)
Klumpp, A. R.; Lawson, C. L.
1988-01-01
Routines provided for common scalar, vector, matrix, and quaternion operations. Computer program extends Ada programming language to include linear-algebra capabilities similar to HAS/S programming language. Designed for such avionics applications as software for Space Station.
NASA Astrophysics Data System (ADS)
Kanai, Masahiro; Isojima, Shin; Nishinari, Katsuhiro; Tokihiro, Tetsuji
2009-05-01
In this paper, we propose the ultradiscrete optimal velocity model, a cellular-automaton model for traffic flow, by applying the ultradiscrete method for the optimal velocity model. The optimal velocity model, defined by a differential equation, is one of the most important models; in particular, it successfully reproduces the instability of high-flux traffic. It is often pointed out that there is a close relation between the optimal velocity model and the modified Korteweg-de Vries (mkdV) equation, a soliton equation. Meanwhile, the ultradiscrete method enables one to reduce soliton equations to cellular automata which inherit the solitonic nature, such as an infinite number of conservation laws, and soliton solutions. We find that the theory of soliton equations is available for generic differential equations and the simulation results reveal that the model obtained reproduces both absolutely unstable and convectively unstable flows as well as the optimal velocity model.
Viscosity ratio effects on the coalescence of two equal-sized drops in a two-dimensional linear flow
NASA Astrophysics Data System (ADS)
Yoon, Yosang; Borrell, Marcos; Park, C. Charles; Leal, L. Gary
2005-02-01
The effect of the dispersed to continuous-phase viscosity ratio on the flow-induced coalescence of two equal-sized drops with clean interfaces was experimentally investigated. The experimental systems consisted of polybutadiene drops suspended in polydimethylsiloxane. The bulk-phase rheological properties of the fluids are Newtonian under the very weak flow conditions of the coalescence experiment (strain rate, G < 0.08 s-1). Both head-on and glancing collisions were studied in a purely extensional flow (flow-type parameter, α = 1.0) for the viscosity ratio (λ) range from O(0.1) to O(10). For head-on collisions, the dimensionless drainage times increased with the capillary number (Ca) as Ca3/2 for all the viscosity ratios, which is consistent with theoretical predictions based on a simple film drainage model. The drainage time at a fixed Ca increased with the viscosity ratio and scaled as λ0.82. In the case of glancing collisions, the critical coalescence conditions were examined by changing the initial offset, which results in different collision trajectories. In an earlier paper (Yang et al. 2001) that studied a system with a viscosity ratio of 0.096, the critical capillary number (Cac) for coalescence always decreased with the increasing offset. However, the present study shows that when the viscosity ratio is greater than O(0.1), the critical capillary number decreases with increasing offset only for the smallest offsets, but then increases with increasing offset until a critical offset is reached above which coalescence is not observed. This is because coalescence for the larger offsets occurs in the extensional quadrant (φ > 45°) after the external flow has begun to pull the drops apart. At small offsets, drops coalesced in the compression quadrant with an orientation angle, φ < 45°. At the larger offsets, drops also coalesced in the compression quadrant for small Ca, but above some critical Ca, the coalescence angle jumped abruptly (i.e. with a very
NASA Astrophysics Data System (ADS)
Grigoriev, Roman; Qin, Tongran
2015-11-01
Convection in layers of nonvolatile liquids with a free surface driven by a horizontal temperature gradient is a fairly well-studies problem. It is described by several nondimensional parameters: the Prandtl number Pr , the Marangoni number Ma , and the Rayleigh number Ra (or the dynamic Bond number BoD = Ra / Ma). Previous studies mostly focused on characterizing the critical Ma and the nature of the convective pattern (e.g., stationary rolls or traveling waves) as a function of Pr and BoD . To understand convection in volatile liquids one also has to consider the transport of heat and mass in the gas layer above the liquid. In confined geometries, the composition of the gas phase plays a very important role, since air tends to suppress phase change at the interface and thereby the amount of latent heat released or absorbed at the interface as a result of evaporation or condensation. Linear stability analysis of the problem based on a two-sided model shows that, for BoD = O (1) , both the critical Ma and the critical wave length of the pattern increase as the average concentration of air decreases. The predictions of linear stability analysis are found to be in good agreement with previous experimental and numerical studies of both nonvolatile and volatile fluids.
How to Handle 'Routine' Inspections
Chris T. Brown
2013-04-01
Nondestructive examination (NDE) utilized for preservice or inservice inspection provides valuable information relating to the quality and integrity of fabricated components. This document describes the importance of detailed preparation for nondestructive examination regardless of the complexity, periodicity or routine nature of the examinations/inspections being performed.
NASA Astrophysics Data System (ADS)
Bohorquez, Patricio; Ancey, Christophe
2015-09-01
In this article we propose a stochastic bed load transport formulation within the framework of the frictional shallow-water equations in which the sediment transport rate results from the difference between the entrainment and deposition of particles. First we show that the Saint-Venant-Exner equations are linearly unstable in most cases for a uniform base flow down an inclined erodible bed for Shields numbers in excess of the threshold for incipient sediment motion allowing us to compute noise-induced pattern formation for Froude numbers below 2. The wavelength of the bed forms are selected naturally due to the absolute character of the bed instability and the existence of a maximum growth rate at a finite wavelength when the particle diffusivity coefficient and the water eddy viscosity are present as for Turing-like instability. A numerical method is subsequently developed to analyze the performance of the model and theoretical results through three examples: the simulation of the fluctuations of the particle concentration using a stochastic Langevin equation, the deterministic simulation of anti-dunes formation over an erodible slope in full sediment-mobility conditions, and the computation of noise-induced pattern formation in hybrid stochastic-deterministic flows down a periodic flume. The full non-linear numerical simulations are in excellent agreement with the theoretical solutions. We conclude highlighting that the proposed depth-averaged formulation explains the developments of upstream migrating anti-dunes in straight flumes since the seminar experiments by Gilbert (1914).
Sétif, Pierre
2015-02-01
The inhibitor methyl viologen (MV) has been widely used in photosynthesis to study oxidative stress. Its effects on electron transfer kinetics in Synechocystis sp. PCC6803 cells were studied to characterize its electron-accepting properties. For the first hundreds of flashes following MV addition at submillimolar concentrations, the kinetics of NADPH formation were hardly modified (less than 15% decrease in signal amplitude) with a significant signal decrease only observed after more flashes or continuous illumination. The dependence of the P700 photooxidation kinetics on the MV concentration exhibited a saturation effect at 0.3 mM MV, a concentration which inhibits the recombination reactions in photosystem I. The kinetics of NADPH formation and decay under continuous light with MV at 0.3 mM showed that MV induces the oxidation of the NADP pool in darkness and that the yield of linear electron transfer decreased by only 50% after 1.5-2 photosystem-I turnovers. The unexpectedly poor efficiency of MV in inhibiting NADPH formation was corroborated by in vitro flash-induced absorption experiments with purified photosystem-I, ferredoxin and ferredoxin-NADP(+)-oxidoreductase. These experiments showed that the second-order rate constants of MV reduction are 20 to 40-fold smaller than the competing rate constants involved in reduction of ferredoxin and ferredoxin-NADP(+)-oxidoreductase. The present study shows that MV, which accepts electrons in vivo both at the level of photosystem-I and ferredoxin, can be used at submillimolar concentrations to inhibit recombination reactions in photosystem-I with only a moderate decrease in the efficiency of fast reactions involved in linear electron transfer and possibly cyclic electron transfer.
Modal analysis of measurements from a large-scale VIV model test of a riser in linearly sheared flow
NASA Astrophysics Data System (ADS)
Lie, H.; Kaasen, K. E.
2006-05-01
Large-scale model testing of a tensioned steel riser in well-defined sheared current was performed at Hanøytangen outside Bergen, Norway in 1997. The length of the model was 90 m and the diameter was 3 cm. The aim of the present work is to look into this information and try to improve the understanding of vortex-induced vibrations (VIV) for cases with very high order of responding modes, and in particular to study if and under which circumstances the riser motions would be single-mode or multi-mode. The measurement system consisted of 29 biaxial gauges for bending moment. The signals are processed to yield curvature and displacement and further to identify modes of vibration. A modal approach is used successfully employing a combination of signal filtering and least-squares fitting of precalculated mode-shapes. As a part of the modal analysis, it is demonstrated that the equally spaced instrumentation limited the maximum mode number to be extracted to be equal to the number of instrumentation locations. This imposed a constraint on the analysis of in-line (IL) vibration, which occurs at higher frequencies and involves higher modes than cross-flow (CF). The analysis has shown that in general the riser response was irregular (i.e. broad-banded) and that the degree of irregularity increases with the flow speed. In some tests distinct spectral peaks could be seen, corresponding to a dominating mode. No occurrences of single-mode (lock-in) were seen. The IL response is more broad-banded than the CF response and contains higher frequencies. The average value of the displacement r.m.s over the length of the riser is computed to indicate the magnitude of VIV motion during one test. In the CF direction the average displacement is typically 1/4 of the diameter, almost independent of the flow speed. For the IL direction the values are in the range 0.05 0.08 of the diameter. The peak frequency taken from the spectra of the CF displacement at riser midpoint show approximately
Boundary-layer linear stability theory
NASA Technical Reports Server (NTRS)
Mack, L. M.
1984-01-01
Most fluid flows are turbulent rather than laminar and the reason for this was studied. One of the earliest explanations was that laminar flow is unstable, and the linear instability theory was first developed to explore this possibility. A series of early papers by Rayleigh produced many notable results concerning the instability of inviscid flows, such as the discovery of inflectional instability. Viscosity was commonly thought to act only to stabilize the flow, and flows with convex velocity profiles appeared to be stable. The investigations that led to a viscous theory of boundary layer instability was reported. The earliest application of linear stability theory to transition prediction calculated the amplitude ratio of the most amplified frequency as a function of Reynolds number for a Blasius boundary layer, and found that this quantity had values between five and nine at the observed Ret. The experiment of Schubauer and Skramstad (1947) completely reversed the prevailing option and fully vindicated the Gottingen proponents of the theory. This experiment demonstrated the existence of instability waves in a boundary layer, their connection with transition, and the quantitative description of their behavior by the theory of Tollmien and Schlichting. It is generally accepted that flow parameters such as pressure gradient, suction and heat transfer qualitatively affect transition in the manner predicted by the linear theory, and in particular that a flow predicted to be stable by the theory should remain laminar. The linear theory, in the form of the e9, or N-factor is today in routine use in engineering studies of laminar flow. The stability theory to boundary layers with pressure gradients and suction was applied. The only large body of numerical results for exact boundary layer solutions before the advent of the computer age by calculating the stability characteristics of the Falkner-Skan family of velocity profiles are given. When the digital computer
Boundary-layer linear stability theory
NASA Astrophysics Data System (ADS)
Mack, L. M.
1984-06-01
Most fluid flows are turbulent rather than laminar and the reason for this was studied. One of the earliest explanations was that laminar flow is unstable, and the linear instability theory was first developed to explore this possibility. A series of early papers by Rayleigh produced many notable results concerning the instability of inviscid flows, such as the discovery of inflectional instability. Viscosity was commonly thought to act only to stabilize the flow, and flows with convex velocity profiles appeared to be stable. The investigations that led to a viscous theory of boundary layer instability was reported. The earliest application of linear stability theory to transition prediction calculated the amplitude ratio of the most amplified frequency as a function of Reynolds number for a Blasius boundary layer, and found that this quantity had values between five and nine at the observed Ret. The experiment of Schubauer and Skramstad (1947) completely reversed the prevailing option and fully vindicated the Gottingen proponents of the theory. This experiment demonstrated the existence of instability waves in a boundary layer, their connection with transition, and the quantitative description of their behavior by the theory of Tollmien and Schlichting. It is generally accepted that flow parameters such as pressure gradient, suction and heat transfer qualitatively affect transition in the manner predicted by the linear theory, and in particular that a flow predicted to be stable by the theory should remain laminar. The linear theory, in the form of the e9, or N-factor is today in routine use in engineering studies of laminar flow. The stability theory to boundary layers with pressure gradients and suction was applied. The only large body of numerical results for exact boundary layer solutions before the advent of the computer age by calculating the stability characteristics of the Falkner-Skan family of velocity profiles are given. When the digital computer
NASA Astrophysics Data System (ADS)
Polychronidis, H. C.; Marechal, J.
The thermal wake of a heated wire in a 9-m/sec turbulent flow subjected to uniform compression or expansion by the section geometry is investigated experimentally, considering the heat of the wire as a passive contaminant. One working section has an inlet 15 cm high and 60 cm wide tapering smoothly over its 1-m length to an outlet 60 cm high and 15 cm wide; the other has inlet and outlet 15 cm high and 60 cm wide tapering to 30 by 30 cm at the midpoint of its 1-m length. Mean and fluctuating temperature and velocity fields and temperature-signal probability-density functions are determined, and the results are presented graphically. It is shown that turbulent diffusion is potentiated by compression and suppressed by expansion. A theoretical model of thermal-wake structure is proposed. The design of the test apparatus is treated in detail in an appendix.
Rotavirus vaccines in routine use.
Tate, Jacqueline E; Parashar, Umesh D
2014-11-01
Vaccines are now available to combat rotavirus, the most common cause of severe diarrhea among children worldwide. We review clinical trial data for available rotavirus vaccines and summarize postlicensure data on effectiveness, impact, and safety from countries routinely using these vaccines in national programs. In these countries, rotavirus vaccines have reduced all-cause diarrhea and rotavirus hospitalizations by 17%-55% and 49%-92%, respectively, and all-cause diarrhea deaths by 22%-50% in some settings. Indirect protection of children who are age-ineligible for rotavirus vaccine has also been observed in some high and upper middle income countries. Experience with routine use of rotavirus vaccines in lower middle income countries has been limited to date, but vaccine introductions in such countries have been increasing in recent years. The risk-benefit analysis of rotavirus vaccines is extremely favorable but other strategies to improve the effectiveness of the vaccine, particularly in lower middle income settings, should be considered.
MATHEMATICAL ROUTINES FOR ENGINEERS AND SCIENTISTS
NASA Technical Reports Server (NTRS)
Kantak, A. V.
1994-01-01
The purpose of this package is to provide the scientific and engineering community with a library of programs useful for performing routine mathematical manipulations. This collection of programs will enable scientists to concentrate on their work without having to write their own routines for solving common problems, thus saving considerable amounts of time. This package contains sixteen subroutines. Each is separately documented with descriptions of the invoking subroutine call, its required parameters, and a sample test program. The functions available include: maxima, minima, and sort of vectors; factorials; random number generator (uniform or Gaussian distribution); complimentary error function; fast Fourier Transformation; Simpson's Rule integration; matrix determinate and inversion; Bessel function (J Bessel function for any order, and modified Bessel function for zero order); roots of a polynomial; roots of non-linear equation; and the solution of first order ordinary differential equations using Hamming's predictor-corrector method. There is also a subroutine for using a dot matrix printer to plot a given set of y values for a uniformly increasing x value. This package is written in FORTRAN 77 (Super Soft Small System FORTRAN compiler) for batch execution and has been implemented on the IBM PC computer series under MS-DOS with a central memory requirement of approximately 28K of 8 bit bytes for all subroutines. This program was developed in 1986.
Global routine vaccination coverage, 2014.
Subaiya, Saleena; Dumolard, Laure; Lydon, Patrick; Gacic-Dobo, Marta; Eggers, Rudolf; Conklin, Laura
2015-11-13
The year 2014 marked the 40th anniversary of the World Health Organization’s (WHO) Expanded Program on Immunization, which was established to ensure equitable access to routine immunization services (1). Since 1974, global coverage with the four core vaccines (Bacille Calmette- Guérin vaccine [BCG; for protection against tuberculosis], diphtheria-tetanus-pertussis [DTP] vaccine, poliovirus vaccine, and measles vaccine) has increased from <5% to ≥85%, and additional vaccines have been added to the recommended schedule. Coverage with the 3rd dose of DTP vaccine (DTP3) by age 12 months is an indicator of immunization program performance because it reflects completion of the basic infant immunization schedule; coverage with other vaccines, including the 3rd dose of poliovirus vaccine (polio3); the 1st dose of measles-containing vaccine (MCV1) is also assessed. Estimated global DTP3 coverage has remained at 84%–86% since 2009, with estimated 2014 coverage at 86%. Estimated global coverage for the 2nd routine dose of measles-containing vaccine (MCV2) was 38% by age 24 months and 56% when older age groups were included, similar to levels reported in 2013 (36% and 55%, respectively). To reach and sustain high immunization coverage in all countries, adequate vaccine stock management and additional opportunities for immunization, such as through routine visits in the second year of life, are integral components to strengthening immunization programs and reducing morbidity and mortality from vaccine preventable diseases. PMID:26562454
Splenic rupture following routine colonoscopy.
Rasul, Tabraze; Leung, Edmund; McArdle, Kirsten; Pathak, Rajiv; Dalmia, Sanjay
2010-10-01
Splenic rupture is a life-threatening condition characterized by internal hemorrhage, often difficult to diagnose. Colonoscopy is a gold standard routine diagnostic test to investigate patients with gastrointestinal symptoms as well as to those on the screening program for colorectal cancer. Splenic injury is seldomly discussed during consent for colonoscopy, as opposed to colonic perforation, as its prevalence accounts for less than 0.1%. A 66-year-old Caucasian woman with no history of collagen disorder was electively admitted for routine colonoscopy for surveillance of adenoma. She was admitted following the procedure for re-dosing of warfarin, which was stopped prior to the colonoscopy. The patient was found collapsed on the ward the following day with clinical shock and anemia. Computed tomography demonstrated grade 4 splenic rupture. Immediate blood transfusion and splenectomy was required. Splenic rupture following routine colonoscopy is extremely rare. Awareness of it on this occasion saved the patient's life. Despite it being a rare association, the seriousness warrants inclusion in all information leaflets concerning colonoscopy and during its consent.
NASA Technical Reports Server (NTRS)
Corke, Thomas c.; Thomas, FLint, O.; Huang, Junhui
2007-01-01
This work involved the documentation and control of flow separation that occurs over low pressure turbine (LPT) blades at low Reynolds numbers. A specially constructed linear cascade was utilized to study the flow field over a generic LPT cascade consisting of Pratt & Whitney "Pak-B" shaped blades. Flow visualization, surface pressure measurements, LDV measurements, and hot-wire anemometry were conducted to examine the flow fields with and without separation control. Experimental conditions were chosen to give a range of chord Reynolds numbers (based on axial chord and inlet velocity) from 10,000 to 100,000, and a range of freestream turbulence intensities from u'/U(infinity) = 0.08 to 2.85 percent. The blade pressure distributions were measured and used to identify the region of separation that depends on Reynolds number and the turbulence intensity. Separation control was performed using dielectric barrier discharge (DBD) plasma actuators. Both steady and unsteady actuation were implemented and found to work well. The comparison between the steady and unsteady actuators showed that the unsteady actuators worked better than the steady ones. For the steady actuators, it was found that the separated region is significantly reduced. For the unsteady actuators, where the signal was pulsed, the separation was eliminated. The total pressure losses (a low Reynolds number) was reduced by approximately a factor of two. It was also found that lowest plasma duty cycle (10 percent in this work) was as effective as the highest plasma duty cycle (50 percent in this work). The mechanisms of the steady and unsteady plasma actuators were studied. It was suggested by the experimental results that the mechanism for the steady actuators is turbulence tripping, while the mechanism for the unsteady actuators is to generate a train of spanwise structures that promote mixing.
NASA Astrophysics Data System (ADS)
Flikweert, A. J.; Zimmermann, T.; Merdzhanova, T.; Weigand, D.; Appenzeller, W.; Gordijn, A.
2012-01-01
A concept for high-rate plasma deposition (PECVD) of hydrogenated microcrystalline silicon on moving substrates (dynamic deposition) is developed and evaluated. The chamber allows for substrates up to a size of 40 × 40 cm2. The deposition plasma is sustained between linear VHF electrodes (60 MHz) and a moving substrate. Due to the gas flow geometry and the high degree of source gas depletion, from the carrier's point of view the silane concentration varies when passing the electrodes. This is known to lead to different growth conditions which can induce transitions from microcrystalline to amorphous growth. The effect of different silane concentrations is simulated at a standard RF showerhead electrode by intentionally varying the silane concentration during deposition in static mode. This variation may decrease the layer quality of microcrystalline silicon, due to a shift of the crystallinity away from the optimum. However, adapting the input silane concentration, state-of-the-art solar cells are obtained. Microcrystalline cells (ZnO : Al/Ag back contacts) produced by the linear VHF plasma sources show an efficiency of 7.9% and 6.6% for depositions in static and dynamic mode, respectively.
Schenone, Agustina V; Culzoni, María J; Marsili, Nilda R; Goicoechea, Héctor C
2013-06-01
The performance of MCR-ALS was studied in the modeling of non-linear kinetic-spectrophotometric data acquired by a stopped-flow system for the quantitation of tartrazine in the presence of brilliant blue and sunset yellow FCF as possible interferents. In the present work, MCR-ALS and U-PCA/RBL were firstly applied to remove the contribution of unexpected components not included in the calibration set. Secondly, a polynomial function was used to model the non-linear data obtained by the implementation of the algorithms. MCR-ALS was the only strategy that allowed the determination of tartrazine in test samples accurately. Therefore, it was applied for the analysis of tartrazine in beverage samples with minimum sample preparation and short analysis time. The proposed method was validated by comparison with a chromatographic procedure published in the literature. Mean recovery values between 98% and 100% and relative errors of prediction values between 4% and 9% were indicative of the good performance of the method.
Global routine vaccination coverage, 2013.
Harris, Jennifer B; Gacic-Dobo, Marta; Eggers, Rudolf; Brown, David W; Sodha, Samir V
2014-11-21
In 1974, the World Health Organization (WHO) established the Expanded Program on Immunization to ensure that all children have access to routinely recommended vaccines. Since then, global coverage with the four core vaccines (Bacille Calmette-Guérin vaccine [for protection against tuberculosis], diphtheria-tetanus-pertussis vaccine [DTP], polio vaccine, and measles vaccine) has increased from <5% to ≥84%, and additional vaccines have been added to the recommended schedule. Coverage with the third dose of DTP vaccine (DTP3) by age 12 months is a key indicator of immunization program performance. Estimated global DTP3 coverage has remained at 83%-84% since 2009, with estimated 2013 coverage at 84%. Global coverage estimates for the second routine dose of measles-containing vaccine (MCV2) are reported for the first time in 2013; global coverage was 35% by the end of the second year of life and 53% when including older age groups. Improvements in equity of access and use of immunization services will help ensure that all children are protected from vaccine-preventable diseases. PMID:25412062
Evolutionary Dynamics of Digitized Organizational Routines
ERIC Educational Resources Information Center
Liu, Peng
2013-01-01
This dissertation explores the effects of increased digitization on the evolutionary dynamics of organizational routines. Do routines become more flexible, or more rigid, as the mix of digital technologies and human actors changes? What are the mechanisms that govern the evolution of routines? The dissertation theorizes about the effects of…
42 CFR 493.931 - Routine chemistry.
Code of Federal Regulations, 2013 CFR
2013-10-01
... 42 Public Health 5 2013-10-01 2013-10-01 false Routine chemistry. 493.931 Section 493.931 Public... Proficiency Testing Programs by Specialty and Subspecialty § 493.931 Routine chemistry. (a) Program content and frequency of challenge. To be approved for proficiency testing for routine chemistry, a...
42 CFR 493.931 - Routine chemistry.
Code of Federal Regulations, 2014 CFR
2014-10-01
... 42 Public Health 5 2014-10-01 2014-10-01 false Routine chemistry. 493.931 Section 493.931 Public... Proficiency Testing Programs by Specialty and Subspecialty § 493.931 Routine chemistry. (a) Program content and frequency of challenge. To be approved for proficiency testing for routine chemistry, a...
42 CFR 493.931 - Routine chemistry.
Code of Federal Regulations, 2012 CFR
2012-10-01
... 42 Public Health 5 2012-10-01 2012-10-01 false Routine chemistry. 493.931 Section 493.931 Public... Proficiency Testing Programs by Specialty and Subspecialty § 493.931 Routine chemistry. (a) Program content and frequency of challenge. To be approved for proficiency testing for routine chemistry, a...
42 CFR 493.931 - Routine chemistry.
Code of Federal Regulations, 2010 CFR
2010-10-01
... 42 Public Health 5 2010-10-01 2010-10-01 false Routine chemistry. 493.931 Section 493.931 Public... Proficiency Testing Programs by Specialty and Subspecialty § 493.931 Routine chemistry. (a) Program content and frequency of challenge. To be approved for proficiency testing for routine chemistry, a...
42 CFR 493.931 - Routine chemistry.
Code of Federal Regulations, 2011 CFR
2011-10-01
... 42 Public Health 5 2011-10-01 2011-10-01 false Routine chemistry. 493.931 Section 493.931 Public... Proficiency Testing Programs by Specialty and Subspecialty § 493.931 Routine chemistry. (a) Program content and frequency of challenge. To be approved for proficiency testing for routine chemistry, a...
NASA Astrophysics Data System (ADS)
Hunter, William Ross; Van Oevelen, Dick; Witte, Ursula
2013-04-01
Over 1 million km2 of seafloor experience permanent low-oxygen conditions within oxygen minimum zones (OMZs). OMZs are predicted to grow as a consequence of climate change, potentially affecting oceanic biogeochemical cycles. The Arabian Sea OMZ impinges upon the western Indian continental margin at bathyal depths (150 - 1500m) producing a strong depth dependent oxygen gradient at the sea floor. The influence of the OMZ upon the short term processing of organic matter by sediment ecosystems was investigated using in situ stable isotope pulse chase experiments. These deployed doses of 13C:15N labeled organic matter onto the sediment surface at four stations from across the OMZ (water depth 540 - 1100 m; [O2] = 0.35 - 15 μM). In order to prevent experimentally anoxia, the mesocosms were not sealed. 13C and 15N labels were traced into sediment, bacteria, fauna and 13C into sediment porewater DIC and DOC. However, the DIC and DOC flux to the water column could not be measured, limiting our capacity to obtain mass-balance for C in each experimental mesocosm. Linear Inverse Modeling (LIM) provides a method to obtain a mass-balanced model of carbon flow that integrates stable-isotope tracer data with community biomass and biogeochemical flux data from a range of sources. Here we present an adaptation of the LIM methodology used to investigate how ecosystem structure influenced carbon flow across the Indian margin OMZ. We demonstrate how oxygen conditions affect food-web complexity, affecting the linkages between the bacteria, foraminifera and metazoan fauna, and their contributions to benthic respiration. The food-web models demonstrate how changes in ecosystem complexity are associated with oxygen availability across the OMZ and allow us to obtain a complete carbon budget for the stationa where stable-isotope labelling experiments were conducted.
NASA Technical Reports Server (NTRS)
Magnus, A. E.; Epton, M. A.
1981-01-01
Panel aerodynamics (PAN AIR) is a system of computer programs designed to analyze subsonic and supersonic inviscid flows about arbitrary configurations. A panel method is a program which solves a linear partial differential equation by approximating the configuration surface by a set of panels. An overview of the theory of potential flow in general and PAN AIR in particular is given along with detailed mathematical formulations. Fluid dynamics, the Navier-Stokes equation, and the theory of panel methods were also discussed.
Sturgeon, Catharine; Hill, Robert; Hortin, Glen L; Thompson, Douglas
2010-01-01
There is increasing pressure to provide cost-effective healthcare based on “best practice.” Consequently, new biomarkers are only likely to be introduced into routine clinical biochemistry departments if they are supported by a strong evidence base and if the results will improve patient management and outcome. This requires convincing evidence of the benefits of introducing the new test, ideally reflected in fewer hospital admissions, fewer additional investigations and/or fewer clinic visits. Carefully designed audit and cost-benefit studies in relevant patient groups must demonstrate that introducing the biomarker delivers an improved and more effective clinical pathway. From the laboratory perspective, pre-analytical requirements must be thoroughly investigated at an early stage. Good stability of the biomarker in relevant physiological matrices is essential to avoid the need for special processing. Absence of specific timing requirements for sampling and knowledge of the effect of medications that might be used to treat the patients in whom the biomarker will be measured is also highly desirable. Analytically, automation is essential in modern high-throughput clinical laboratories. Assays must therefore be robust, fulfilling standard requirements for linearity on dilution, precision and reproducibility, both within- and between-run. Provision of measurements by a limited number of specialized reference laboratories may be most appropriate, especially when a new biomarker is first introduced into routine practice. PMID:21137030
NASA Astrophysics Data System (ADS)
Wang, Baoyuan
The objective of this research is to develop an efficient and accurate methodology to resolve flow non-linearity of fluid-structural interaction. To achieve this purpose, a numerical strategy to apply the detached-eddy simulation (DES) with a fully coupled fluid-structural interaction model is established for the first time. The following novel numerical algorithms are also created: a general sub-domain boundary mapping procedure for parallel computation to reduce wall clock simulation time, an efficient and low diffusion E-CUSP (LDE) scheme used as a Riemann solver to resolve discontinuities with minimal numerical dissipation, and an implicit high order accuracy weighted essentially non-oscillatory (WENO) scheme to capture shock waves. The Detached-Eddy Simulation is based on the model proposed by Spalart in 1997. Near solid walls within wall boundary layers, the Reynolds averaged Navier-Stokes (RANS) equations are solved. Outside of the wall boundary layers, the 3D filtered compressible Navier-Stokes equations are solved based on large eddy simulation(LES). The Spalart-Allmaras one equation turbulence model is solved to provide the Reynolds stresses in the RANS region and the subgrid scale stresses in the LES region. An improved 5th order finite differencing weighted essentially non-oscillatory (WENO) scheme with an optimized epsilon value is employed for the inviscid fluxes. The new LDE scheme used with the WENO scheme is able to capture crisp shock profiles and exact contact surfaces. A set of fully conservative 4th order finite central differencing schemes are used for the viscous terms. The 3D Navier-Stokes equations are discretized based on a conservative finite differencing scheme. The unfactored line Gauss-Seidel relaxation iteration is employed for time marching. A general sub-domain boundary mapping procedure is developed for arbitrary topology multi-block structured grids with grid points matched on sub-domain boundaries. Extensive numerical experiments
Ananyev, Gennady; Gates, Colin; Dismukes, G Charles
2016-09-01
We have measured flash-induced oxygen quantum yields (O2-QYs) and primary charge separation (Chl variable fluorescence yield, Fv/Fm) in vivo among phylogenetically diverse microalgae and cyanobacteria. Higher O2-QYs can be attained in cells by releasing constraints on charge transfer at the Photosystem II (PSII) acceptor side by adding membrane-permeable benzoquinone (BQ) derivatives that oxidize plastosemiquinone QB(-) and QBH2. This method allows uncoupling PSII turnover from its natural regulation in living cells, without artifacts of isolating PSII complexes. This approach reveals different extents of regulation across species, controlled at the QB(-) acceptor site. Arthrospira maxima is confirmed as the most efficient PSII-WOC (water oxidizing complex) and exhibits the least regulation of flux. Thermosynechococcus elongatus exhibits an O2-QY of 30%, suggesting strong downregulation. WOC cycle simulations with the most accurate model (VZAD) show that a light-driven backward transition (net addition of an electron to the WOC, distinct from recombination) occurs in up to 25% of native PSIIs in the S2 and S3 states, while adding BQ prevents backward transitions and increases the lifetime of S2 and S3 by 10-fold. Backward transitions occur in PSIIs that have plastosemiquinone radicals in the QB site and are postulated to be physiologically regulated pathways for storing light energy as proton gradient through direct PSII-cyclic electron flow (PSII-CEF). PSII-CEF is independent of classical PSI/cyt-b6f-CEF and provides an alternative proton translocation pathway for energy conversion. PSII-CEF enables variable fluxes between linear and cyclic electron pathways, thus accommodating species-dependent needs for redox and ion-gradient energy sources powered by a single photosystem.
Ananyev, Gennady; Gates, Colin; Dismukes, G Charles
2016-09-01
We have measured flash-induced oxygen quantum yields (O2-QYs) and primary charge separation (Chl variable fluorescence yield, Fv/Fm) in vivo among phylogenetically diverse microalgae and cyanobacteria. Higher O2-QYs can be attained in cells by releasing constraints on charge transfer at the Photosystem II (PSII) acceptor side by adding membrane-permeable benzoquinone (BQ) derivatives that oxidize plastosemiquinone QB(-) and QBH2. This method allows uncoupling PSII turnover from its natural regulation in living cells, without artifacts of isolating PSII complexes. This approach reveals different extents of regulation across species, controlled at the QB(-) acceptor site. Arthrospira maxima is confirmed as the most efficient PSII-WOC (water oxidizing complex) and exhibits the least regulation of flux. Thermosynechococcus elongatus exhibits an O2-QY of 30%, suggesting strong downregulation. WOC cycle simulations with the most accurate model (VZAD) show that a light-driven backward transition (net addition of an electron to the WOC, distinct from recombination) occurs in up to 25% of native PSIIs in the S2 and S3 states, while adding BQ prevents backward transitions and increases the lifetime of S2 and S3 by 10-fold. Backward transitions occur in PSIIs that have plastosemiquinone radicals in the QB site and are postulated to be physiologically regulated pathways for storing light energy as proton gradient through direct PSII-cyclic electron flow (PSII-CEF). PSII-CEF is independent of classical PSI/cyt-b6f-CEF and provides an alternative proton translocation pathway for energy conversion. PSII-CEF enables variable fluxes between linear and cyclic electron pathways, thus accommodating species-dependent needs for redox and ion-gradient energy sources powered by a single photosystem. PMID:27117512
Sidorin, Anatoly
2010-01-05
In linear accelerators the particles are accelerated by either electrostatic fields or oscillating Radio Frequency (RF) fields. Accordingly the linear accelerators are divided in three large groups: electrostatic, induction and RF accelerators. Overview of the different types of accelerators is given. Stability of longitudinal and transverse motion in the RF linear accelerators is briefly discussed. The methods of beam focusing in linacs are described.
Active Movement Warm-Up Routines
ERIC Educational Resources Information Center
Walter, Teri; Quint, Ashleigh; Fischer, Kim; Kiger, Joy
2011-01-01
This article presents warm-ups that are designed to physiologically and psychologically prepare students for vigorous physical activity. An active movement warm-up routine is made up of three parts: (1) active warm-up movement exercises, (2) general preparation, and (3) the energy system. These warm-up routines can be used with all grade levels…
Wong, Oscar Gee-Wan; Lo, C K; Chow, Joanne N K; Tsun, Obe K L; Szeto, Elaine; Liu, Stephanie S; Ngan, Hextan Y S; Cheung, Annie N Y
2012-05-01
High-risk human papillomavirus (HR-HPV) DNA detection in cervical cytology samples is useful for primary screening of cervical cancer and for triage of patients with equivocal cytological findings. The GenoFlow HPV array test (GF assay; Diagcor Bioscience Inc., Hong Kong) was recently developed to detect 33 HPV genotypes by a "flowthrough" hybridization technology. In this study, we assessed the analytical sensitivity and reproducibility of the GF assay and compared its genotyping results with those of the Linear Array (LA) assay (Roche Molecular Diagnostics, Indianapolis, IN), using 400 archived liquid-based cytology samples representing the full range of cytology findings. Genotyping findings of the GF and LA assays were concordant or compatible for 93.44% of tested samples, with a good (κ = 0.797) to very good (κ = 0.812) strength of agreement for assay-common and oncogenic HPV types, respectively. The two assays showed good (κ = 0.635) agreement in detecting infections with multiple HPV genotypes. The lowest detection limits of the GF assay for HPV16 and HPV18 were 25 copies and 20 copies, respectively. Repeat testing of 60 samples by use of two different lots of the GF assay revealed no discordant results, suggesting good reproducibility of the assay. Both assays achieved approximately 80% and 100% sensitivity for identifying cases of atypical squamous cells of undetermined significance (ASC-US) and low-grade squamous intraepithelial lesions (LSIL) with subsequent detection of LSIL+ and high-grade squamous intraepithelial lesions or higher (HSIL+) in 2 years, respectively. Among ASC-US samples, the GF assay achieved the highest specificity (23.08%) for indicating subsequent identification of HSIL compared with the LA (19.23%) and Hybrid Capture 2 (HC2) (8.97%) assays. The GF and LA assays showed significant discrepancy in detecting HPV genotypes 11, 26, 39, 52, and 66. More sensitive detection of HPV52 by GF assay offers an advantage in regions where HPV52
NASA Astrophysics Data System (ADS)
Yamamoto, Akira; Yokoya, Kaoru
2015-02-01
An overview of linear collider programs is given. The history and technical challenges are described and the pioneering electron-positron linear collider, the SLC, is first introduced. For future energy frontier linear collider projects, the International Linear Collider (ILC) and the Compact Linear Collider (CLIC) are introduced and their technical features are discussed. The ILC is based on superconducting RF technology and the CLIC is based on two-beam acceleration technology. The ILC collaboration completed the Technical Design Report in 2013, and has come to the stage of "Design to Reality." The CLIC collaboration published the Conceptual Design Report in 2012, and the key technology demonstration is in progress. The prospects for further advanced acceleration technology are briefly discussed for possible long-term future linear colliders.
NASA Astrophysics Data System (ADS)
Yamamoto, Akira; Yokoya, Kaoru
An overview of linear collider programs is given. The history and technical challenges are described and the pioneering electron-positron linear collider, the SLC, is first introduced. For future energy frontier linear collider projects, the International Linear Collider (ILC) and the Compact Linear Collider (CLIC) are introduced and their technical features are discussed. The ILC is based on superconducting RF technology and the CLIC is based on two-beam acceleration technology. The ILC collaboration completed the Technical Design Report in 2013, and has come to the stage of "Design to Reality." The CLIC collaboration published the Conceptual Design Report in 2012, and the key technology demonstration is in progress. The prospects for further advanced acceleration technology are briefly discussed for possible long-term future linear colliders.
ERIC Educational Resources Information Center
Bull, Leah E.; Oliver, Chris; Callaghan, Eleanor; Woodcock, Kate A.
2015-01-01
Several neurodevelopmental disorders are associated with preference for routine and challenging behavior following changes to routines. We examine individuals with Prader-Willi syndrome, who show elevated levels of this behavior, to better understand how previous experience of a routine can affect challenging behavior elicited by disruption to…
ERIC Educational Resources Information Center
Walkiewicz, T. A.; Newby, N. D., Jr.
1972-01-01
A discussion of linear collisions between two or three objects is related to a junior-level course in analytical mechanics. The theoretical discussion uses a geometrical approach that treats elastic and inelastic collisions from a unified point of view. Experiments with a linear air track are described. (Author/TS)
Taking medicine at home - create a routine
... page: //medlineplus.gov/ency/patientinstructions/000613.htm Taking medicine at home - create a routine To use the ... teeth. Find Ways to Help You Remember Your Medicines You can: Set the alarm on your clock, ...
Simnple, portable, 3-D projection routine
Wagner, J.S.
1987-04-01
A 3-D projection routine is presented for use in computer graphics applications. The routine is simple enough to be considered portable, and easily modified for special problems. There is often the need to draw three-dimensional objects on a two-dimensional plotting surface. For the object to appear realistic, perspective effects must be included that allow near objects to appear larger than distant objects. Several 3-D projection routines are commercially available, but they are proprietary, not portable, and not easily changed by the user. Most are restricted to surfaces that are functions of two variables. This makes them unsuitable for viewing physical objects such as accelerator prototypes or propagating beams. This report develops a very simple algorithm for 3-D projections; the core routine is only 39 FORTRAN lines long. It can be easily modified for special problems. Software dependent calls are confined to simple drivers that can be exchanged when different plotting software packages are used.
Habitual routines in task-performing groups
NASA Technical Reports Server (NTRS)
Gersick, C. J.; Hackman, J. R.
1990-01-01
Groups, like individuals, often develop habitual routines for dealing with frequently encountered stimuli. Although such routines are consequential for group life and work, little is known about them. This paper reconnoiters the territory of habitual behavior in groups that perform work within organizations. We offer a definition of group habits, identify their functions and dysfunctions, suggest how they develop and are maintained, and identify the circumstances when they are likely to be altered or abandoned. Throughout, we give special attention to the social nature of habitual routines in groups, to the interaction between habitual behavior and group life cycle phenomena, and to the role of the organizational context in prompting, shaping, and terminating habitual routines.
NASA Technical Reports Server (NTRS)
Utku, S.
1969-01-01
A general purpose digital computer program for the in-core solution of linear equilibrium problems of structural mechanics is documented. The program requires minimum input for the description of the problem. The solution is obtained by means of the displacement method and the finite element technique. Almost any geometry and structure may be handled because of the availability of linear, triangular, quadrilateral, tetrahedral, hexahedral, conical, triangular torus, and quadrilateral torus elements. The assumption of piecewise linear deflection distribution insures monotonic convergence of the deflections from the stiffer side with decreasing mesh size. The stresses are provided by the best-fit strain tensors in the least squares at the mesh points where the deflections are given. The selection of local coordinate systems whenever necessary is automatic. The core memory is used by means of dynamic memory allocation, an optional mesh-point relabelling scheme and imposition of the boundary conditions during the assembly time.
Christofilos, N.C.; Polk, I.J.
1959-02-17
Improvements in linear particle accelerators are described. A drift tube system for a linear ion accelerator reduces gap capacity between adjacent drift tube ends. This is accomplished by reducing the ratio of the diameter of the drift tube to the diameter of the resonant cavity. Concentration of magnetic field intensity at the longitudinal midpoint of the external sunface of each drift tube is reduced by increasing the external drift tube diameter at the longitudinal center region.
Routine Radiological Environmental Monitoring Plan. Volume 1
Bechtel Nevada
1999-12-31
The U.S. Department of Energy manages the Nevada Test Site in a manner that meets evolving DOE Missions and responds to the concerns of affected and interested individuals and agencies. This Routine Radiological Monitoring Plan addressess complicance with DOE Orders 5400.1 and 5400.5 and other drivers requiring routine effluent monitoring and environmental surveillance on the Nevada Test Site. This monitoring plan, prepared in 1998, addresses the activities conducted onsite NTS under the Final Environmental Impact Statement and Record of Decision. This radiological monitoring plan, prepared on behalf of the Nevada Test Site Landlord, brings together sitewide environmental surveillance; site-specific effluent monitoring; and operational monitoring conducted by various missions, programs, and projects on the NTS. The plan provides an approach to identifying and conducting routine radiological monitoring at the NTS, based on integrated technical, scientific, and regulatory complicance data needs.
Active stereo vision routines using PRISM-3
NASA Astrophysics Data System (ADS)
Antonisse, Hendrick J.
1992-11-01
This paper describes work in progress on a set of visual routines and supporting capabilities implemented on the PRISM-3 real-time vision system. The routines are used in an outdoor robot retrieval task. The task requires the robot to locate a donor agent -- a Hero2000 -- which holds the object to be retrieved, to navigate to the donor, to accept the object from the donor, and return to its original location. The routines described here will form an integral part of the navigation and wide-area search tasks. Active perception is exploited to locate the donor using real-time stereo ranging directed by a pan/tilt/verge mechanism. A framework for orchestrating visual search has been implemented and is briefly described.
Optimized groundwater containment using linear programming
Quinn, J.J.; Johnson, R.L.; Durham, L.A.
1998-07-01
Groundwater extraction systems are typically installed to contain contaminant plumes. These systems are expensive to install and maintain. A traditional approach to designing such a wellfield is to use a series of trial-and-error simulations to test the effects of various well locations and pump rates. However, optimal locations and pump rates of extraction wells are difficult to determine when the objectives of the potential pumping scheme and the site hydrogeology are considered. This paper describes a case study of an application of linear programming theory to determine optimal well placement and pump rates. Calculations were conducted by using ModMan to link a calibrated MODFLOW flow model with LINDO, a linear programming package. Past activities at the site under study included disposal of contaminants in pits. Several groundwater plumes have been identified, and others may be present. The area of concern is bordered on three sides by a wetland, which receives a portion of its input water budget as groundwater discharge from the disposal area. The objective function of the optimization was to minimize the rate of groundwater extraction while preventing discharge to the marsh across a user-specified boundary. In this manner, the optimization routine selects well locations and pump rates to produce a groundwater divide along this boundary.
Routine environmental monitoring schedule, calendar year 1998
McKinney, S.M.
1997-11-24
This document provides the Environmental Restorations Contractor (ERC) and the Project Hanford Management Contractor (PHMC) a schedule in accordance with the HNF-PRO-454, Inactive Waste Sites` HNF-PRO-455, Solid Waste 3 Management4 and BHI-EE-02, Environmental Requirements, of monitoring and sampling, routines for the near-facility environmental monitoring program during calendar year (CY) 1998. Every attempt will be made to consistently follow this schedule; any deviation from this schedule will be documented by an internal memorandum (DSI) explaining the reason for the deviation. The DSI will be issued by the scheduled performing organization and directed to Environmental Monitoring and Investigations. The survey frequencies for particular sites are determined by the technical judgment of Environmental Monitoring and investigations and may depend on the site history, radiological status, use, and general conditions. Additional surveys may be requested at irregular frequencies if conditions warrant. All radioactive wastes sites are scheduled to be surveyed at least annually. Any newly discovered wastes sites not documented by this schedule will be included in the revised schedule for CY 1999. The outside perimeter road surveys of 200 East and West Area and the rail survey from the 300 Area to Columbia Center will be performed in the year 2000 per agreement with Department of Energy, Richland Field Office. This schedule does not discuss staffing needs, nor does it list the monitoring equipment to be used in completing specific routines. Personnel performing routines to meet this schedule shall communicate any need for 1332 assistance in completing these routines to Radiological Control management and Environmental Monitoring and Investigations. After each routine survey is completed, a copy of the survey record, maps, and data sheets will be forwarded to Environmental Monitoring and Investigations. These routine surveys will not be considered complete until this
Reis, K V; Venere, P C; Sampaio, I; Rêgo, P S; Vallinoto, M; Souza, I L
2015-09-01
The aim of this study was to estimate the genetic diversity and structure of the only known population of minnow Astyanax xavante, which inhabits a stretch of river including several waterfalls. The FST values among the samples were not significant, except between two populations separated by a 30 m waterfall. Nevertheless, haplotype and nucleotide diversity increased in the downstream direction, indicating that gene flow is unidirectional, which indicates this genetic pattern as downstairs gene flow, as it has the effect of increasing genetic diversity in the downstream direction. PMID:26212357
Reis, K V; Venere, P C; Sampaio, I; Rêgo, P S; Vallinoto, M; Souza, I L
2015-09-01
The aim of this study was to estimate the genetic diversity and structure of the only known population of minnow Astyanax xavante, which inhabits a stretch of river including several waterfalls. The FST values among the samples were not significant, except between two populations separated by a 30 m waterfall. Nevertheless, haplotype and nucleotide diversity increased in the downstream direction, indicating that gene flow is unidirectional, which indicates this genetic pattern as downstairs gene flow, as it has the effect of increasing genetic diversity in the downstream direction.
NASA Astrophysics Data System (ADS)
RamReddy, Chetteti; Pradeepa, Teegala
2016-05-01
Based on the nonlinear variation of density with temperature (NDT) in the buoyancy term, the mixed convection flow along a vertical plate of a micropolar fluid saturated porous medium is considered. In addition, the effect of homogeneous-heterogeneous reaction and convective boundary condition has been taken into account. Using lie scaling group transformations, the similarity representation is attained for the system of partial differential equations, prior to being solved by a spectral quasilinearization method. The results show that in the presence of aiding and opposing flow situations, both the species concentration and mass transfer rate decreases when the strength of homogeneous and heterogeneous reaction parameters are enhanced.
Support Routines for In Situ Image Processing
NASA Technical Reports Server (NTRS)
Deen, Robert G.; Pariser, Oleg; Yeates, Matthew C.; Lee, Hyun H.; Lorre, Jean
2013-01-01
This software consists of a set of application programs that support ground-based image processing for in situ missions. These programs represent a collection of utility routines that perform miscellaneous functions in the context of the ground data system. Each one fulfills some specific need as determined via operational experience. The most unique aspect to these programs is that they are integrated into the large, in situ image processing system via the PIG (Planetary Image Geometry) library. They work directly with space in situ data, understanding the appropriate image meta-data fields and updating them properly. The programs themselves are completely multimission; all mission dependencies are handled by PIG. This suite of programs consists of: (1)marscahv: Generates a linearized, epi-polar aligned image given a stereo pair of images. These images are optimized for 1-D stereo correlations, (2) marscheckcm: Compares the camera model in an image label with one derived via kinematics modeling on the ground, (3) marschkovl: Checks the overlaps between a list of images in order to determine which might be stereo pairs. This is useful for non-traditional stereo images like long-baseline or those from an articulating arm camera, (4) marscoordtrans: Translates mosaic coordinates from one form into another, (5) marsdispcompare: Checks a Left Right stereo disparity image against a Right Left disparity image to ensure they are consistent with each other, (6) marsdispwarp: Takes one image of a stereo pair and warps it through a disparity map to create a synthetic opposite- eye image. For example, a right eye image could be transformed to look like it was taken from the left eye via this program, (7) marsfidfinder: Finds fiducial markers in an image by projecting their approximate location and then using correlation to locate the markers to subpixel accuracy. These fiducial markets are small targets attached to the spacecraft surface. This helps verify, or improve, the
NASA Technical Reports Server (NTRS)
Magnus, Alfred E.; Epton, Michael A.
1981-01-01
An outline of the derivation of the differential equation governing linear subsonic and supersonic potential flow is given. The use of Green's Theorem to obtain an integral equation over the boundary surface is discussed. The engineering techniques incorporated in the PAN AIR (Panel Aerodynamics) program (a discretization method which solves the integral equation for arbitrary first order boundary conditions) are then discussed in detail. Items discussed include the construction of the compressibility transformations, splining techniques, imposition of the boundary conditions, influence coefficient computation (including the concept of the finite part of an integral), computation of pressure coefficients, and computation of forces and moments.
Is routine drainage necessary after pancreaticoduodenectomy?
Wang, Qiang; Jiang, Yong-Jian; Li, Ji; Yang, Feng; Di, Yang; Yao, Lie; Jin, Chen; Fu, De-Liang
2014-01-01
With the development of imaging technology and surgical techniques, pancreatic resections to treat pancreatic tumors, ampulla tumors, and other pancreatic diseases have increased. Pancreaticoduodenectomy, one type of pancreatic resection, is a complex surgery with the loss of pancreatic integrity and various anastomoses. Complications after pancreaticoduodenectomy such as pancreatic fistulas and anastomosis leakage are common and significantly associated with patient outcomes. Pancreatic fistula is one of the most important postoperative complications; this condition can cause intraperitoneal hemorrhage, septic shock, or even death. An effective way has not yet been found to avoid the occurrence of pancreatic fistula. In most medical centers, the frequency of pancreatic fistula has remained between 9% and 13%. The early detection and routine drainage of anastomotic fistulas, pancreatic fistulas, bleeding, or other intra-abdominal fluid collections after pancreatic resections are considered as important and effective ways to reduce postoperative complications and the mortality rate. However, many recent studies have argued that routine drainage after abdominal operations, including pancreaticoduodenectomies, does not affect the incidence of postoperative complications. Although inserting drains after pancreatic resections continues to be a routine procedure, its necessity remains controversial. This article reviews studies of the advantages and disadvantages of routine drainage after pancreaticoduodenectomy and discusses the necessity of this procedure. PMID:25009383
Integrating Communication Skills into Functional Routines & Activities.
ERIC Educational Resources Information Center
Stremel, Kathleen
This training module on integrating communication skills into functional routines and activities is from the Mississippi Early Education Program for Children with Multiple Disabilities, a program designed to train Individuals with Disabilities Education Act Part H service coordinators and service providers to use family centered strategies. The…
Routines. Infant/Toddler Caregiving: A Guide.
ERIC Educational Resources Information Center
Gonzalez-Mena, Janet
Intended for use in conjunction with videos illustrating key concepts and caregiving techniques, this guide focuses on how the daily routines of caring for infants and toddlers can become opportunities for promoting the child's learning and development and for deepening the relationship between child and caregiver. Special attention is given to…
40 CFR 141.621 - Routine monitoring.
Code of Federal Regulations, 2013 CFR
2013-07-01
... 40 Protection of Environment 24 2013-07-01 2013-07-01 false Routine monitoring. 141.621 Section 141.621 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER PROGRAMS... system that begins using a disinfectant other than UV light after the dates in subpart U of this part...
40 CFR 141.621 - Routine monitoring.
Code of Federal Regulations, 2012 CFR
2012-07-01
... 40 Protection of Environment 24 2012-07-01 2012-07-01 false Routine monitoring. 141.621 Section 141.621 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER PROGRAMS... system that begins using a disinfectant other than UV light after the dates in subpart U of this part...
40 CFR 141.621 - Routine monitoring.
Code of Federal Regulations, 2011 CFR
2011-07-01
... 40 Protection of Environment 23 2011-07-01 2011-07-01 false Routine monitoring. 141.621 Section 141.621 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER PROGRAMS... system that begins using a disinfectant other than UV light after the dates in subpart U of this part...
40 CFR 141.621 - Routine monitoring.
Code of Federal Regulations, 2014 CFR
2014-07-01
... 40 Protection of Environment 23 2014-07-01 2014-07-01 false Routine monitoring. 141.621 Section 141.621 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER PROGRAMS... begins using a disinfectant other than UV light after the dates in subpart U of this part for...
40 CFR 141.621 - Routine monitoring.
Code of Federal Regulations, 2010 CFR
2010-07-01
... 40 Protection of Environment 22 2010-07-01 2010-07-01 false Routine monitoring. 141.621 Section 141.621 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER PROGRAMS... system that begins using a disinfectant other than UV light after the dates in subpart U of this part...
Is routine drainage necessary after pancreaticoduodenectomy?
Wang, Qiang; Jiang, Yong-Jian; Li, Ji; Yang, Feng; Di, Yang; Yao, Lie; Jin, Chen; Fu, De-Liang
2014-07-01
With the development of imaging technology and surgical techniques, pancreatic resections to treat pancreatic tumors, ampulla tumors, and other pancreatic diseases have increased. Pancreaticoduodenectomy, one type of pancreatic resection, is a complex surgery with the loss of pancreatic integrity and various anastomoses. Complications after pancreaticoduodenectomy such as pancreatic fistulas and anastomosis leakage are common and significantly associated with patient outcomes. Pancreatic fistula is one of the most important postoperative complications; this condition can cause intraperitoneal hemorrhage, septic shock, or even death. An effective way has not yet been found to avoid the occurrence of pancreatic fistula. In most medical centers, the frequency of pancreatic fistula has remained between 9% and 13%. The early detection and routine drainage of anastomotic fistulas, pancreatic fistulas, bleeding, or other intra-abdominal fluid collections after pancreatic resections are considered as important and effective ways to reduce postoperative complications and the mortality rate. However, many recent studies have argued that routine drainage after abdominal operations, including pancreaticoduodenectomies, does not affect the incidence of postoperative complications. Although inserting drains after pancreatic resections continues to be a routine procedure, its necessity remains controversial. This article reviews studies of the advantages and disadvantages of routine drainage after pancreaticoduodenectomy and discusses the necessity of this procedure. PMID:25009383
An Examination of Latino Students' Homework Routines
ERIC Educational Resources Information Center
Martinez, Sylvia
2011-01-01
Homework appears to be positively associated with better student outcomes. Although some researchers have explored the connection between time spent on homework and minority student achievement, few have examined the homework routines of Latino youth. Interviews with Latino high school students show that they have some difficulty completing daily…
Action Selection in Complex Routinized Sequential Behaviors
ERIC Educational Resources Information Center
Ruh, Nicolas; Cooper, Richard P.; Mareschal, Denis
2010-01-01
We report two experiments in which errors and interaction latencies were recorded during routinization of hierarchically structured computer-based tasks. Experiment 1 demonstrates that action selection is slowed at subtask transitions, especially when selecting lower frequency actions. This frequency effect is compounded by concurrent performance…
The Acquisition of Routines in Child Language
ERIC Educational Resources Information Center
Gleason, Jean Berko; Weintraub, Sandra
1976-01-01
Investigates performance of the highly constrained Hallowe'en "trick or treat" routine in 115 children from 2 to 16 years of age. Changes in competence and role of parental input are examined in relation to cognitive and social factors. (Author/RM)
libvaxdata: VAX data format conversion routines
Baker, Lawrence M.
2005-01-01
libvaxdata provides a collection of routines for converting numeric data-integer and floating-point-to and from the formats used on a Digital Equipment Corporation1 (DEC) VAX 32-bit minicomputer (Brunner, 1991). Since the VAX numeric data formats are inherited from those used on a DEC PDP-11 16-bit minicomputer, these routines can be used to convert PDP-11 data as well. VAX numeric data formats are also the default data formats used on DEC Alpha 64-bit minicomputers running OpenVMS The libvaxdata routines are callable from Fortran or C. They require that the caller use two's-complement format for integer data and IEEE 754 format (ANSI/IEEE, 1985) for floating-point data. They also require that the 'natural' size of a C int type (integer) is 32 bits. That is the case for most modern 32-bit and 64-bit computer systems. Nevertheless, you may wish to consult the Fortran or C compiler documentation on your system to be sure. Some Fortran compilers support conversion of VAX numeric data on-the-fly when reading or writing unformatted files, either as a compiler option or a run-time I/O option. This feature may be easier to use than the libvaxdata routines. Consult the Fortran compiler documentation on your system to determine if this alternative is available to you. 1Later Compaq Computer Corporation, now Hewlett-Packard Company
The first year of routine Herschel observations
NASA Astrophysics Data System (ADS)
2011-06-01
MEETING REPORT The successful completion of the first year of routine science operations of ESA's Herschel Space Observatory was marked by a Specialist Discussion Meeting of the RAS held in January 2011. A few of the early science highlights from the mission were presented. Derek Ward-Thompson and David Clements summarize.
Individual Values, Learning Routines and Academic Procrastination
ERIC Educational Resources Information Center
Dietz, Franziska; Hofer, Manfred; Fries, Stefan
2007-01-01
Background: Academic procrastination, the tendency to postpone learning activities, is regarded as a consequence of postmodern values that are prominent in post-industrialized societies. When students strive for leisure goals and have no structured routines for academic tasks, delaying strenuous learning activities becomes probable. Aims: The…
NASA Astrophysics Data System (ADS)
Magnaudet, Jacques
2003-06-01
The problem of a spherical drop of arbitrary density and viscosity moving near a wall under the effect of a body force is analysed theoretically in the limit where the wall lies in the inner region of the flow disturbance, the distance between the drop and the wall being large compared to the drop radius. The drop may move in an arbitrary direction with respect to the wall, and the undisturbed flow field is assumed to comprise a steady uniform shear or solid-body rotation and a time-dependent uniform stream, the variations of which take place over time scales large compared to the viscous diffusion time. An exact force balance with no limitation on the magnitude of inertial effects is obtained by using the reciprocal theorem. Explicit expressions for the contributions of temporal acceleration, slip and shear or rotation to the total hydrodynamic force are derived in the limit of small-but-finite inertial effects. The connection between these near-wall results and inertial lift and drag corrections in an unbounded flow is discussed. Situations of particular interest in which the lift force results from a combination of contributions due to unsteadiness and advection, like the case of a particle moving near the bottom wall of a centrifuge, are also examined.
Designing linear systolic arrays
Kumar, V.K.P.; Tsai, Y.C. . Dept. of Electrical Engineering)
1989-12-01
The authors develop a simple mapping technique to design linear systolic arrays. The basic idea of the technique is to map the computations of a certain class of two-dimensional systolic arrays onto one-dimensional arrays. Using this technique, systolic algorithms are derived for problems such as matrix multiplication and transitive closure on linearly connected arrays of PEs with constant I/O bandwidth. Compared to known designs in the literature, the technique leads to modular systolic arrays with constant hardware in each PE, few control lines, lexicographic data input/output, and improved delay time. The unidirectional flow of control and data in this design assures implementation of the linear array in the known fault models of wafer scale integration.
Improved Electrohydraulic Linear Actuators
NASA Technical Reports Server (NTRS)
Hamtil, James
2004-01-01
A product line of improved electrohydraulic linear actuators has been developed. These actuators are designed especially for use in actuating valves in rocket-engine test facilities. They are also adaptable to many industrial uses, such as steam turbines, process control valves, dampers, motion control, etc. The advantageous features of the improved electrohydraulic linear actuators are best described with respect to shortcomings of prior electrohydraulic linear actuators that the improved ones are intended to supplant. The flow of hydraulic fluid to the two ports of the actuator cylinder is controlled by a servo valve that is controlled by a signal from a servo amplifier that, in turn, receives an analog position-command signal (a current having a value between 4 and 20 mA) from a supervisory control system of the facility. As the position command changes, the servo valve shifts, causing a greater flow of hydraulic fluid to one side of the cylinder and thereby causing the actuator piston to move to extend or retract a piston rod from the actuator body. A linear variable differential transformer (LVDT) directly linked to the piston provides a position-feedback signal, which is compared with the position-command signal in the servo amplifier. When the position-feedback and position-command signals match, the servo valve moves to its null position, in which it holds the actuator piston at a steady position.
2006-11-17
Software that simulates and inverts electromagnetic field data for subsurface electrical properties (electrical conductivity) of geological media. The software treats data produced by a time harmonic source field excitation arising from the following antenna geometery: loops and grounded bipoles, as well as point electric and magnetic dioples. The inversion process is carried out using a non-linear conjugate gradient optimization scheme, which minimizes the misfit between field data and model data using a least squares criteria.more » The software is an upgrade from the code NLCGCS_MP ver 1.0. The upgrade includes the following components: Incorporation of new 1 D field sourcing routines to more accurately simulate the 3D electromagnetic field for arbitrary geologic& media, treatment for generalized finite length transmitting antenna geometry (antennas with vertical and horizontal component directions). In addition, the software has been upgraded to treat transverse anisotropy in electrical conductivity.« less
NASA Astrophysics Data System (ADS)
Batchaev, A. M.
2016-05-01
In this paper, a Reynolds number increase transition from self-oscillations close to single-frequency ones to the temporally chaotic regime in the flow in a cylindrical channel driven by a spatially periodic force with four half-periods is experimentally investigated. The parameter ɛ proportional to the mean rate of the kinetic energy dissipation in unit mass per unit time associated with perturbations in the fluid is used as a basic characteristic of self-oscillations. The Reynolds number dependence ɛ(Re) for single frequency self-oscillations is considered theoretically.
Routine Operational Environmental Monitoring schedule, CY 1994
Schmidt, J.W.
1993-12-01
This document provides Health Physics (HP) a schedule in accordance with the Environmental Compliance Manual, WHC-CM-7-5, of monitoring and sampling routines for the Operational Environmental Monitoring (OEM) Program during calendar year (CY) 1994. The survey frequencies for particular sites are determined by the technical judgment of EES and may depend on the site history, radiological status, use, and general conditions. Additional surveys may be requested at irregular frequencies if conditions warrant. All radioactive waste sites are scheduled to be surveyed annually at a minimum. Any newly discovered waste sites not documented by this schedule will be included in the revised schedule for CY 1995. This schedule does not discuss the manpower needs nor does it list the monitoring equipment to be used in completing specific routines.
Fortran graphics routines for the Macintosh
Shore, B.W.
1992-06-01
The Language Systems MPW Fortran is a popular Fortran compiler for the Macintosh. Unfortunately, it does not have any built-in calls to graphics routines (such as are available with Graflib on the NLTSS), so there is no simple way to make x-y plots from calls within Fortran. Instead, a file of data must be created and a commercial plotting routine (such as IGOR or KALEIDAGRAPH) or a spreadsheet with graphics (such as WINGZ) must be applied to post-process the data. The Macintosh does have available many built-in calls (to the Macintosh Toolbox) that allow drawing shapes and lines with quickdraw, but these are not designed for plotting functions and are difficult to learn to use. This work outlines some Fortran routines that can be called from LS Fortran to make the necessary calls to the Macintosh toolbox to create simple two-dimensional plots or contour plots. The source code DEMOGRAF.F shows how these routines may be used. DEMOGRAF.F simply demonstrates some Fortran subroutines that can be called with language systems MPW Fortran on the Macintosh to plot arrays of numbers. The subroutines essentially mimic the functionality that has been available at LTSS and NLTSS and UNICOS at LLNL. The graphics primitives are kept in four separate files, each containing several subroutines. The subroutines are compiled and stored in a library file, LIBgraf.o. Makefile is used to link this library to the source code. A discussion is included on requirements for interactive plotting of functions.
Verification and quality control of routine hematology analyzers.
Vis, J Y; Huisman, A
2016-05-01
Verification of hematology analyzers (automated blood cell counters) is mandatory before new hematology analyzers may be used in routine clinical care. The verification process consists of several items which comprise among others: precision, accuracy, comparability, carryover, background and linearity throughout the expected range of results. Yet, which standard should be met or which verification limit be used is at the discretion of the laboratory specialist. This paper offers practical guidance on verification and quality control of automated hematology analyzers and provides an expert opinion on the performance standard that should be met by the contemporary generation of hematology analyzers. Therefore (i) the state-of-the-art performance of hematology analyzers for complete blood count parameters is summarized, (ii) considerations, challenges, and pitfalls concerning the development of a verification plan are discussed, (iii) guidance is given regarding the establishment of reference intervals, and (iv) different methods on quality control of hematology analyzers are reviewed. PMID:27161194
Update on Routine Childhood and Adolescent Immunizations.
Ackerman, Lani K; Serrano, Jacquelyn L
2015-09-15
Recommendations for routine vaccinations in children and adolescents have changed multiple times in recent years, based on findings in clinical trials, licensure of new vaccines, and evidence of waning immunity. Despite the overwhelming success of vaccinations, vaccine delay and refusal are leading to pockets of vaccine-preventable diseases. Schedules for diphtheria and tetanus toxoids, and acellular pertussis (DTaP); hepatitis A and B; Haemophilus influenzae type b (Hib); inactivated poliovirus; varicella; and measles, mumps, and rubella are unchanged. However, since 2008, 13-valent pneumococcal conjugate vaccine has replaced the 7-valent vaccine; a new two-dose oral rotavirus vaccine has been approved; use of the tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis (Tdap) vaccine has been expanded to children seven to 10 years of age who received fewer than five doses of DTaP, as well as during each pregnancy; a booster dose of meningococcal vaccine is recommended in adolescents 16 to 18 years of age (unless the first dose was given after 16 years of age); new meningococcal vaccines have been approved for use in infants at high risk of meningococcal disease; influenza vaccine has been expanded to routine use in all children six months and older; and the human papillomavirus vaccine has been approved for routine immunization of adolescent boys and girls. For the 2015-2016 influenza season, either live attenuated or inactivated vaccine can be administered to healthy children two to eight years of age.
Colgate, S.A.
1958-05-27
An improvement is presented in linear accelerators for charged particles with respect to the stable focusing of the particle beam. The improvement consists of providing a radial electric field transverse to the accelerating electric fields and angularly introducing the beam of particles in the field. The results of the foregoing is to achieve a beam which spirals about the axis of the acceleration path. The combination of the electric fields and angular motion of the particles cooperate to provide a stable and focused particle beam.
One year of campaigns in Cameroon: effects on routine health services
Mounier-Jack, Sandra; Edengue, Jean Marie; Lagarde, Mylene; Baonga, Simon Franky; Ongolo-Zogo, Pierre
2016-01-01
Background: Targeted campaigns have been reported to disrupt routine health services in low- and middle-income countries. The objective of this study was to evaluate the average effect of public health campaigns over 1 year on routine services such as antenatal care, routine vaccination and outpatient services. Method: We collected daily activity data in 60 health facilities in two regions of Cameroon that traditionally undergo different intensities of campaign activity, the Centre region (low) and the Far North (high), to ascertain effects on routine services. For each outcome, we restricted our analysis to the public health centres for which good data were available and excluded private health facilities given their small number. We used segment-linear regression to account for the longitudinal nature of the data, and assessed whether the number of routine activities decreased in health facilities during periods when campaigns occurred. The analysis controlled for secular trends and serial correlation. Results: We found evidence that vaccination campaigns had a negative impact on routine activities, decreasing outpatient visits when they occurred (Centre: −9.9%, P = 0.079; Far North: −11.6%, P = 0.025). The average negative effect on routine services [outpatient visits −18% (P = 0.02) and antenatal consultations −70% [P = 0.001]) was most pronounced in the Far North during ‘intensive’ campaigns that usually require high mobilization of staff. Discussion: With an increasing number of interventions delivered by campaigns and in the context of elimination and eradication targets, these are important results for countries and agencies to consider. Achieving disease control targets hinges on ensuring high uptake of routine services. Therefore, we suggest that campaigns should systematically monitor ‘impact on routine services’, while also devising concrete strategies to mitigate potential adverse effects. PMID:27175031
NASA Technical Reports Server (NTRS)
2006-01-01
[figure removed for brevity, see original site] Context image for PIA03667 Linear Clouds
These clouds are located near the edge of the south polar region. The cloud tops are the puffy white features in the bottom half of the image.
Image information: VIS instrument. Latitude -80.1N, Longitude 52.1E. 17 meter/pixel resolution.
Note: this THEMIS visual image has not been radiometrically nor geometrically calibrated for this preliminary release. An empirical correction has been performed to remove instrumental effects. A linear shift has been applied in the cross-track and down-track direction to approximate spacecraft and planetary motion. Fully calibrated and geometrically projected images will be released through the Planetary Data System in accordance with Project policies at a later time.
NASA's Jet Propulsion Laboratory manages the 2001 Mars Odyssey mission for NASA's Office of Space Science, Washington, D.C. The Thermal Emission Imaging System (THEMIS) was developed by Arizona State University, Tempe, in collaboration with Raytheon Santa Barbara Remote Sensing. The THEMIS investigation is led by Dr. Philip Christensen at Arizona State University. Lockheed Martin Astronautics, Denver, is the prime contractor for the Odyssey project, and developed and built the orbiter. Mission operations are conducted jointly from Lockheed Martin and from JPL, a division of the California Institute of Technology in Pasadena.
Parent routines for managing cystic fibrosis in children
Grossoehme, Daniel H.; Filigno, Stephanie Spear; Bishop, Meredith
2014-01-01
Management of cystic fibrosis (CF) is burdensome and adherence is often suboptimal. Family routines are associated with adherence and health outcomes in other disease populations. Few studies have examined routines in CF. The study's aim was to describe parent experiences developing and utilizing CF care routines. Semi-structured interviews with a convenience sample of 25 parents of children under 13 years of age with CF were analyzed using phenomenological analysis. Three domains emerged: parent experiences developing a routine, support systems facilitating maintenance of routines, and challenges with maintaining care routines. Parents found routines difficult to establish, used trial and error, encountered barriers, and found support helpful to manage care demands. Some parents chose to deviate from their routine. Providing anticipatory guidance to promote the use of care routines and strategies to manage potential challenges may facilitate use of routines and improve CF management. PMID:24838648
Domestic violence in pregnancy: midwives and routine questioning.
Stonard, Gill; Whapples, Emma
2016-01-01
The Confidential enquiry into maternal and child health (CEMACH) (2004) set the standard for maternity care to protect women from domestic violence. Twelve women who were murdered by their partner and 43 further deaths from disclosure with no appropriate referrals prompted the routine enquiry for domestic violence to be initiated in 2000. The death rate from domestic violence had marginally decreased slightly in the latest report from The Centre for Maternal and Child Enquiries (CMACE) (2011) with 11 women murdered by their partner and 34 further deaths from disclosure with no referrals. The aim of this article is to review the current literature in order to explore evidence that questions the confidence of midwives when asking about domestic violence in pregnancy. The article aims to highlight the concerns that midwives face when confronted with a positive disclosure of domestic violence, and to provide a flow chart to aid in referral. PMID:26975130
NASA Technical Reports Server (NTRS)
Dietz, J. B.
1973-01-01
The EHFR program reference information which is presented consists of the following subprogram detailed data: purpose-description of the routine, a list of the calling programs, an argument list description, nomenclature definition, flow charts, and a compilation listing of each subprogram. Each of the EHFR subprograms were developed specifically for this routine and do not have an applicability of a general nature. Single precision accuracy available on the Univac 1108 is used exclusively in all but two of the 31 EHFR subprograms. The double precision variables required are identified in the nomenclature definition of the two subprograms that require them. A concise definition of the purpose, function, and capabilities is made in the subprogram description. The description references the appropriate Volume 1 sections of the report which contain the applicable detailed definitions, governing equations, and assumptions used. The compilation listing of each subprogram defines the program/data storage requirements, identifies the labeled block common data required, and identifies other subprograms called during execution. For Vol. 1, see N73-31842.
PC Basic Linear Algebra Subroutines
1992-03-09
PC-BLAS is a highly optimized version of the Basic Linear Algebra Subprograms (BLAS), a standardized set of thirty-eight routines that perform low-level operations on vectors of numbers in single and double-precision real and complex arithmetic. Routines are included to find the index of the largest component of a vector, apply a Givens or modified Givens rotation, multiply a vector by a constant, determine the Euclidean length, perform a dot product, swap and copy vectors, andmore » find the norm of a vector. The BLAS have been carefully written to minimize numerical problems such as loss of precision and underflow and are designed so that the computation is independent of the interface with the calling program. This independence is achieved through judicious use of Assembly language macros. Interfaces are provided for Lahey Fortran 77, Microsoft Fortran 77, and Ryan-McFarland IBM Professional Fortran.« less
Just a routine operation: a critical discussion.
McClelland, G; Smith, M B
2016-05-01
This article has summarised a critical discussion of the human factors that contributed to the death of a patient from a failure to respond appropriately to a 'can't intubate, can't ventilate' scenario. The contributory factors included the clinical team's inability to communicate, prioritise tasks and demonstrate effective leadership and assertive followership. The film Just a routine operation has now been in circulation for several years. When a system is designed and introduced with the intention of making a change to clinical practice, it can quickly become just another component of an organisation's architecture and complacency around its use can develop. This article has been written specifically for perioperative practitioners to renew the debate around the human factors that contribute to patient harm. By critically discussing Just a routine operation and attempting to review why the incident occurred, this article has attempted to emphasise that some of the conditions and behaviours that contributed to the death of Elaine Bromiley may be latent within our organisations and teams, and may continue to contribute to failures that affect patient safety.
Just a routine operation: a critical discussion.
McClelland, G; Smith, M B
2016-05-01
This article has summarised a critical discussion of the human factors that contributed to the death of a patient from a failure to respond appropriately to a 'can't intubate, can't ventilate' scenario. The contributory factors included the clinical team's inability to communicate, prioritise tasks and demonstrate effective leadership and assertive followership. The film Just a routine operation has now been in circulation for several years. When a system is designed and introduced with the intention of making a change to clinical practice, it can quickly become just another component of an organisation's architecture and complacency around its use can develop. This article has been written specifically for perioperative practitioners to renew the debate around the human factors that contribute to patient harm. By critically discussing Just a routine operation and attempting to review why the incident occurred, this article has attempted to emphasise that some of the conditions and behaviours that contributed to the death of Elaine Bromiley may be latent within our organisations and teams, and may continue to contribute to failures that affect patient safety. PMID:27400489
Multiple electron scattering routines for PEREGRINE
White, J A
1999-08-23
The Monte Carlo electron scattering routines solve multiple elastic scatters in a condensed history approach. The Goudsmit-Saunderson scattering model is used and its implementation is taken from Kawrakow and Bielajew[l]. The subroutines produce an exit angle representing a likely scattering angle of a single incident electron after scattering elastically over a given step size. Two input parameters, {lambda} and {eta}, that depend on the atomic species and incident energy must first be specified. The mapping from species and energy to 77 and {lambda} already existed in the PEREGRINE code and was not redone or modified in any way. The software has been validated by comparisons to Moliere and Goudsmit-Saunderson models of D.W.O. Rogers[2]. As required by licensing considerations, no public domain or copyrighted software has been used in any phase of the preparation of any of these sub-routines or data files. Apart from needing to have {eta} and {lambda} specified through PEREGRINE, the code provided is completely self-contained. Everything is written in the FORTRAN 77 language to simplify inclusion in the existing PEREGRINE package.
Lachenbruch, A.H.
1980-01-01
In their recent paper, Singh & Negi, (This journal, 57, 741-744) contend that if thd slope of the empirical linear relation between heat flow and heat production is interpreted as the decay-length of an exponential depth-distribution of sources, a discrepancy rises, whereas if it is interpreted as the depth of a step distribution, it does not. I should like to point out that their discrepancy follows from their arbitrary assumption of one of a range of physical possibilities unconstrained by the observations; with an equally valid alternate assumption (Lachenbruch 1970) the discrepancy disappears. In any case such discrepancies are probably minor compared to physical difficulties that arise from the step model, and to uncertainties introduced by other assumptions in any simple model.-Author
NASA Technical Reports Server (NTRS)
Budhani, R. C.; Suenaga, M.; Liou, S. H.
1992-01-01
A large shift of the onset of flux-flow resistivity and the irreversibility line H(irr)(T) to higher temperatures is observed in Tl2Ba2Ca2Cu3O10 films containing linear defects created by Ag(+21) ion irradiation. The H(irr)(T), which has a characteristic L shape in highly anisotropic Tl and Bi based cuprates, becomes more like that of YBa2Cu3O7 in the presence of these defects. The Jc at 77 K also shows a large increase as a result of flux localization at the defects. The transport data indicate that in the H-T plane above H(irr)(T) of the unirradiated material, an ensemble of unoccupied defects is required for effective pinning of each flux line in the system.
CPU timing routines for a CONVEX C220 computer system
NASA Technical Reports Server (NTRS)
Bynum, Mary Ann
1989-01-01
The timing routines available on the CONVEX C220 computer system in the Structural Mechanics Division (SMD) at NASA Langley Research Center are examined. The function of the timing routines, the use of the timing routines in sequential, parallel, and vector code, and the interpretation of the results from the timing routines with respect to the CONVEX model of computing are described. The timing routines available on the SMD CONVEX fall into two groups. The first group includes standard timing routines generally available with UNIX 4.3 BSD operating systems, while the second group includes routines unique to the SMD CONVEX. The standard timing routines described in this report are /bin/csh time,/bin/time, etime, and ctime. The routines unique to the SMD CONVEX are getinfo, second, cputime, toc, and a parallel profiling package made up of palprof, palinit, and palsum.
NASA Technical Reports Server (NTRS)
Goldowsky, Michael P. (Inventor)
1987-01-01
A reciprocating linear motor is formed with a pair of ring-shaped permanent magnets having opposite radial polarizations, held axially apart by a nonmagnetic yoke, which serves as an axially displaceable armature assembly. A pair of annularly wound coils having axial lengths which differ from the axial lengths of the permanent magnets are serially coupled together in mutual opposition and positioned with an outer cylindrical core in axial symmetry about the armature assembly. One embodiment includes a second pair of annularly wound coils serially coupled together in mutual opposition and an inner cylindrical core positioned in axial symmetry inside the armature radially opposite to the first pair of coils. Application of a potential difference across a serial connection of the two pairs of coils creates a current flow perpendicular to the magnetic field created by the armature magnets, thereby causing limited linear displacement of the magnets relative to the coils.
Souza, Margarida C; Martins, Valdomiro L; Almeida, Luciano F; Pessoa Neto, Osmundo D; Gaião, Edvaldo N; Araujo, Mario Cesar U
2010-08-15
An automatic method for kinetics independent spectrometric analysis is proposed in this study. It uses a non-linear calibration model that explores concentration gradients generated by a flow-batch analyser (FBA) for the samples, dye, and the single standard solution. The procedure for obtaining the gradients of the dye and standard solution is performed once at the beginning of analysis. The same procedure is applied thereafter for each sample. For illustration, the proposed automatic methodology was applied to determine total protein and albumin in blood serum by using the Biuret and Bromocresol Green (BCG) methods. The measurements were made by using a laboratory-made photometer based on a red and green bicolour LED (Light-Emitting Diode) and a phototransistor, coupled to a "Z" form flow cell. The sample throughput was about 50 h(-1) for albumin and 60 h(-1) for total protein, consuming about 7 microL of sample, 2.6 mL of BCG and 1.2 mL of biuret reagents for each determination. Applying the paired t-test for results from the proposed analyser and the reference method, no statistic differences at 95% confidence level were found. The absolute standard deviation was usually smaller than 0.2 g dL(-1). The proposed method is valuable for the determination of total protein and albumin; and can also be used in other determinations where kinetic effects may or may not exist. PMID:20678663
Souza, Margarida C; Martins, Valdomiro L; Almeida, Luciano F; Pessoa Neto, Osmundo D; Gaião, Edvaldo N; Araujo, Mario Cesar U
2010-08-15
An automatic method for kinetics independent spectrometric analysis is proposed in this study. It uses a non-linear calibration model that explores concentration gradients generated by a flow-batch analyser (FBA) for the samples, dye, and the single standard solution. The procedure for obtaining the gradients of the dye and standard solution is performed once at the beginning of analysis. The same procedure is applied thereafter for each sample. For illustration, the proposed automatic methodology was applied to determine total protein and albumin in blood serum by using the Biuret and Bromocresol Green (BCG) methods. The measurements were made by using a laboratory-made photometer based on a red and green bicolour LED (Light-Emitting Diode) and a phototransistor, coupled to a "Z" form flow cell. The sample throughput was about 50 h(-1) for albumin and 60 h(-1) for total protein, consuming about 7 microL of sample, 2.6 mL of BCG and 1.2 mL of biuret reagents for each determination. Applying the paired t-test for results from the proposed analyser and the reference method, no statistic differences at 95% confidence level were found. The absolute standard deviation was usually smaller than 0.2 g dL(-1). The proposed method is valuable for the determination of total protein and albumin; and can also be used in other determinations where kinetic effects may or may not exist.
An adaptive data-smoothing routine
NASA Technical Reports Server (NTRS)
Taylor, Clayborne D.; Nicolas, David P.
1989-01-01
An adaptive noise reduction algorithm that can be implemented on a microcomputer is developed. Smoothing polynomials are used where the polynomial coefficients are chosen such that the mean-square-error between the noisy and smoothed data is minimized. This approach is equivalent to the implementation of a low-pass finite impulse response filter. The noise reduction depends on the order of the smoothing polynomial. A whiteness test on the error sequence is incorporated to search for the optimal smoothing. Expansion coefficients may be computed via the fast Fourier transform, and the resulting smoothing process is the equivalent of the implementation of an adaptive ideal low-pass filter. Results are obtained for an analytical signal with added white Gaussian noise. The routine may be applied to any smooth signal with additive random noise.
NASA Astrophysics Data System (ADS)
Theofilis, Vassilios
2011-01-01
This article reviews linear instability analysis of flows over or through complex two-dimensional (2D) and 3D geometries. In the three decades since it first appeared in the literature, global instability analysis, based on the solution of the multidimensional eigenvalue and/or initial value problem, is continuously broadening both in scope and in depth. To date it has dealt successfully with a wide range of applications arising in aerospace engineering, physiological flows, food processing, and nuclear-reactor safety. In recent years, nonmodal analysis has complemented the more traditional modal approach and increased knowledge of flow instability physics. Recent highlights delivered by the application of either modal or nonmodal global analysis are briefly discussed. A conscious effort is made to demystify both the tools currently utilized and the jargon employed to describe them, demonstrating the simplicity of the analysis. Hopefully this will provide new impulses for the creation of next-generation algorithms capable of coping with the main open research areas in which step-change progress can be expected by the application of the theory: instability analysis of fully inhomogeneous, 3D flows and control thereof.
When Routines Are Not so Routine: Exploring Coordination Work in Hospitals
ERIC Educational Resources Information Center
Haque, Saira Naim
2010-01-01
Many work processes take place through routines, or recurrent patterns of action. These activities involve individuals from several occupations working across spatial, temporal, and organizational boundaries. Crossing these professional, temporal and spatial boundaries has unique challenges which can lead to coordination failures. In these…
29 CFR 18.406 - Habit; routine practice.
Code of Federal Regulations, 2010 CFR
2010-07-01
... OFFICE OF ADMINISTRATIVE LAW JUDGES Rules of Evidence Relevancy and Its Limits § 18.406 Habit; routine practice. Evidence of the habit of a person or of the routine practice of an organization,...
Rituals and Routines: Supporting Infants and Toddlers and Their Families
ERIC Educational Resources Information Center
Gillespie, Linda; Petersen, Sandra
2012-01-01
The words "routine" and "ritual" are sometimes used interchangeably. Yet there are some important differences. Routines are repeated, predictable events that provide a foundation for the daily tasks in a child's life. Teachers can create a predictable routine in early childhood settings for infants and toddlers, and they can individualize those…
[The controversy of routine articulator mounting in orthodontics].
Wang, Li; Han, Xianglong; Bai, Ding
2013-06-01
Articulators have been widely used by clinicians of dentistry. But routine articulator mounting is still controversial in orthodontics. Orthodontists oriented by gnathology approve routine articulator mounting while nongnathologic orthodontists disapprove it. This article reviews the thoughts of orthodontist that they agree or disagree with routine articulator mounting based on the considerations of biting, temporomandibular disorder (TMD), periodontitis, and so on.
42 CFR 493.1210 - Condition: Routine chemistry.
Code of Federal Regulations, 2011 CFR
2011-10-01
... 42 Public Health 5 2011-10-01 2011-10-01 false Condition: Routine chemistry. 493.1210 Section 493....1210 Condition: Routine chemistry. If the laboratory provides services in the subspecialty of Routine chemistry, the laboratory must meet the requirements specified in §§ 493.1230 through 493.1256, §...
42 CFR 493.1210 - Condition: Routine chemistry.
Code of Federal Regulations, 2012 CFR
2012-10-01
... 42 Public Health 5 2012-10-01 2012-10-01 false Condition: Routine chemistry. 493.1210 Section 493....1210 Condition: Routine chemistry. If the laboratory provides services in the subspecialty of Routine chemistry, the laboratory must meet the requirements specified in §§ 493.1230 through 493.1256, §...
42 CFR 493.1210 - Condition: Routine chemistry.
Code of Federal Regulations, 2014 CFR
2014-10-01
... 42 Public Health 5 2014-10-01 2014-10-01 false Condition: Routine chemistry. 493.1210 Section 493....1210 Condition: Routine chemistry. If the laboratory provides services in the subspecialty of Routine chemistry, the laboratory must meet the requirements specified in §§ 493.1230 through 493.1256, §...
42 CFR 493.1210 - Condition: Routine chemistry.
Code of Federal Regulations, 2010 CFR
2010-10-01
... 42 Public Health 5 2010-10-01 2010-10-01 false Condition: Routine chemistry. 493.1210 Section 493....1210 Condition: Routine chemistry. If the laboratory provides services in the subspecialty of Routine chemistry, the laboratory must meet the requirements specified in §§ 493.1230 through 493.1256, §...
42 CFR 493.1210 - Condition: Routine chemistry.
Code of Federal Regulations, 2013 CFR
2013-10-01
... 42 Public Health 5 2013-10-01 2013-10-01 false Condition: Routine chemistry. 493.1210 Section 493....1210 Condition: Routine chemistry. If the laboratory provides services in the subspecialty of Routine chemistry, the laboratory must meet the requirements specified in §§ 493.1230 through 493.1256, §...
Routines and Transitions: A Guide for Early Childhood Professionals
ERIC Educational Resources Information Center
Malenfont, Nicole
2006-01-01
In early childhood settings, children spend over 50 percent of their time on handwashing, dressing, napping, and other routines and transitions. "Routines and Transitions" is a guide to help turn these routine daily activities into learning experiences. By using transitions wisely, providers not only help children develop skills, but also run a…
Closed cycle refrigeration for routine magnetotransport measurements
NASA Astrophysics Data System (ADS)
Gunawardana, Binuka; Ye, Tianyu; Wegscheider, Werner; Mani, Ramesh
2015-03-01
Condensed matter physics is often interested in the behavior of materials at very low temperatures. Low temperatures have traditionally been realized using liquid helium. However, the recent scarcity of liquid helium and the rapid rise in its cost has encouraged the development of alternative approaches, based on closed cycle refrigerators, for realizing low temperatures. Here, we convey our experiences in developing a home-made, low cost, variable temperature closed cycle refrigeration system for routine magnetotransport measurements down to 10K, and present measurements obtained with this system relating to the electronic properties of the high mobility GaAs/AlGaAs 2D semiconductors system. The setup was constructed to examine 0.5cm × 0.5cm semiconductor chips including up to 49 leads and reach ~ 10K within 3 hours. A computer controlled data acquisition system was assembled to collect resistivity and Hall effect data, and extract the carrier Hall mobility and density as a function of the temperature.
Proteomics for routine identification of microorganisms.
Welker, Martin
2011-08-01
The invention of MALDI-TOF-MS enormously contributed to the understanding of protein chemistry and cell biology. Without this technique proteomics would most likely not be the important discipline it is today. Besides 'true' proteomics, MALDI-TOF-MS was applied for the analysis of microorganisms for their taxonomic characterization from its beginning. This approach has since been developed as a diagnostic tool readily available for routine, high-throughput analysis of microbial isolates from clinical specimens by intact-cell mass spectrometry (ICMS), the direct analysis of whole bacterial cell without a preceding fractionation or separation by chromatography or electrophoresis. ICMS exploits the reproducibility of mass fingerprints for individual bacterial and fungal strains as well as the high similarity of mass fingerprints within a species. Comparison of mass spectral data to genomic sequences emphasized the validity of peak patterns as taxonomic markers. Supported by comprehensive databases, MALDI-TOF-MS-based identification has been widely accepted in clinical laboratories within only a few years.
Don't neglect routine staff meetings.
Board, H K
1982-03-01
Staff meetings are essential to good staff communication. Meetings help keep the grapevine from growing so big that it strangles the group with its rumors. By holding regular meetings with your staff, you create a consistency in your communications that helps prevent problems that you don't even suspect from cropping up. All personnel should attend the meetings. This way everyone hears news at the same time. Be consistent in your use of meetings. Meetings are more effective if you have a planned agenda and a firm time schedule. Encourage your staff to use meetings to talk out problems that affect the group. Once the meeting is over, encourage them to leave their feelings in the room. Many leaders are reluctant, for a variety of reasons, to hold meetings with their staffs. But it's like dieting and exercise; the more you do it, the easier it becomes. This type of meeting will pay rich dividends in staff personal and professional growth and in improved communication. The sense of participation that can be gained by the effective use of staff meetings can lead to high morale and effective staff performance. As you begin to see the results of a cohesive staff functioning together well, you will realize the routine staff meeting is a management tool that should not be overlooked or underused.
Meisner, John W.; Moore, Robert M.; Bienvenue, Louis L.
1985-03-19
Electromagnetic linear induction pump for liquid metal which includes a unitary pump duct. The duct comprises two substantially flat parallel spaced-apart wall members, one being located above the other and two parallel opposing side members interconnecting the wall members. Located within the duct are a plurality of web members interconnecting the wall members and extending parallel to the side members whereby the wall members, side members and web members define a plurality of fluid passageways, each of the fluid passageways having substantially the same cross-sectional flow area. Attached to an outer surface of each side member is an electrically conductive end bar for the passage of an induced current therethrough. A multi-phase, electrical stator is located adjacent each of the wall members. The duct, stators, and end bars are enclosed in a housing which is provided with an inlet and outlet in fluid communication with opposite ends of the fluid passageways in the pump duct. In accordance with a preferred embodiment, the inlet and outlet includes a transition means which provides for a transition from a round cross-sectional flow path to a substantially rectangular cross-sectional flow path defined by the pump duct.
Linearly exact parallel closures for slab geometry
Ji, Jeong-Young; Held, Eric D.; Jhang, Hogun
2013-08-15
Parallel closures are obtained by solving a linearized kinetic equation with a model collision operator using the Fourier transform method. The closures expressed in wave number space are exact for time-dependent linear problems to within the limits of the model collision operator. In the adiabatic, collisionless limit, an inverse Fourier transform is performed to obtain integral (nonlocal) parallel closures in real space; parallel heat flow and viscosity closures for density, temperature, and flow velocity equations replace Braginskii's parallel closure relations, and parallel flow velocity and heat flow closures for density and temperature equations replace Spitzer's parallel transport relations. It is verified that the closures reproduce the exact linear response function of Hammett and Perkins [Phys. Rev. Lett. 64, 3019 (1990)] for Landau damping given a temperature gradient. In contrast to their approximate closures where the vanishing viscosity coefficient numerically gives an exact response, our closures relate the heat flow and nonvanishing viscosity to temperature and flow velocity (gradients)
Linearly exact parallel closures for slab geometry
NASA Astrophysics Data System (ADS)
Ji, Jeong-Young; Held, Eric D.; Jhang, Hogun
2013-08-01
Parallel closures are obtained by solving a linearized kinetic equation with a model collision operator using the Fourier transform method. The closures expressed in wave number space are exact for time-dependent linear problems to within the limits of the model collision operator. In the adiabatic, collisionless limit, an inverse Fourier transform is performed to obtain integral (nonlocal) parallel closures in real space; parallel heat flow and viscosity closures for density, temperature, and flow velocity equations replace Braginskii's parallel closure relations, and parallel flow velocity and heat flow closures for density and temperature equations replace Spitzer's parallel transport relations. It is verified that the closures reproduce the exact linear response function of Hammett and Perkins [Phys. Rev. Lett. 64, 3019 (1990)] for Landau damping given a temperature gradient. In contrast to their approximate closures where the vanishing viscosity coefficient numerically gives an exact response, our closures relate the heat flow and nonvanishing viscosity to temperature and flow velocity (gradients).
NASA Technical Reports Server (NTRS)
Sidwell, Kenneth W.; Baruah, Pranab K.; Bussoletti, John E.; Medan, Richard T.; Conner, R. S.; Purdon, David J.
1990-01-01
A comprehensive description of user problem definition for the PAN AIR (Panel Aerodynamics) system is given. PAN AIR solves the 3-D linear integral equations of subsonic and supersonic flow. Influence coefficient methods are used which employ source and doublet panels as boundary surfaces. Both analysis and design boundary conditions can be used. This User's Manual describes the information needed to use the PAN AIR system. The structure and organization of PAN AIR are described, including the job control and module execution control languages for execution of the program system. The engineering input data are described, including the mathematical and physical modeling requirements. Version 3.0 strictly applies only to PAN AIR version 3.0. The major revisions include: (1) inputs and guidelines for the new FDP module (which calculates streamlines and offbody points); (2) nine new class 1 and class 2 boundary conditions to cover commonly used modeling practices, in particular the vorticity matching Kutta condition; (3) use of the CRAY solid state Storage Device (SSD); and (4) incorporation of errata and typo's together with additional explanation and guidelines.
NASA Technical Reports Server (NTRS)
Epton, Michael A.; Magnus, Alfred E.
1990-01-01
An outline of the derivation of the differential equation governing linear subsonic and supersonic potential flow is given. The use of Green's Theorem to obtain an integral equation over the boundary surface is discussed. The engineering techniques incorporated in the Panel Aerodynamics (PAN AIR) program (a discretization method which solves the integral equation for arbitrary first order boundary conditions) are then discussed in detail. Items discussed include the construction of the compressibility transformation, splining techniques, imposition of the boundary conditions, influence coefficient computation (including the concept of the finite part of an integral), computation of pressure coefficients, and computation of forces and moments. Principal revisions to version 3.0 are the following: (1) appendices H and K more fully describe the Aerodynamic Influence Coefficient (AIC) construction; (2) appendix L now provides a complete description of the AIC solution process; (3) appendix P is new and discusses the theory for the new FDP module (which calculates streamlines and offbody points); and (4) numerous small corrections and revisions reflecting the MAG module rewrite.
Performance Analysis of Apollo Navigational Starter Routine
NASA Technical Reports Server (NTRS)
Ivanov, Stoyan I.; Holt, Greg
2010-01-01
The focus of this project is to recreate and analyze the effectiveness of the original Apollo Starter Routine (ASR) which was used to generate the state vector of the Apollo spacecraft based on a series of radiometric observations. The original Apollo navigation software is unavailable in a modern programming language and the original coding has not been preserved. This necessitates its recreation using the original software documentation. Space Shuttle navigation software does not typically use the ASR or an algorithm like it since the Shuttle s state vector is easily deduced from GPS information or other sources. However, this tactic will be ineffective when trying to determine the state vector of a craft approaching, departing or in orbit around the Moon since the GPS network faces the surface of the Earth, not outer space. The recreation of the ASR from the original documentation is therefore vital as a simulation baseline for the navigation software under development for the Constellation program. The algorithms that make up the ASR will be extracted from the original documentation and adapted for and then implemented in a modern programming language; the majority of it will be coded in Matlab. The ASR s effectiveness will then be tested using simulated tracking data. The ability of the ASR to handle realistically noisy data and the accuracy with which it generates state vectors were analyzed. The ASR proved to be robust enough to process data with range and angle noise as large as 10,000 meters and 10(exp -6) radians together and 300,000 meters and 5x10(exp -4) radians separately at Lunar distances. The ASR was able to handle marginally more noise at distances closer to the Earth where the angle noise was less significant. The ASR is capable of effectively processing 40-80 data points gathered at a rate of one per 20 seconds at close Earth orbit and up to 28-40 data points gathered at a rate of one per minute at distant Earth orbit and Lunar orbit.
Routine perineal shaving on admission in labour.
Basevi, Vittorio; Lavender, Tina
2014-01-01
BackgroundPubic or perineal shaving is a procedure performed before birth in order to lessen the risk of infection if there is a spontaneous perinealtear or if an episiotomy is performed.ObjectivesTo assess the effects of routine perineal shaving before birth onmaternal and neonatal outcomes, according to the best available evidence.Search methodsWe searched the Cochrane Pregnancy and Childbirth Group’s Trials Register (12 June 2014).Selection criteriaAll controlled trials (including quasi-randomised) that compare perineal shaving versus no perineal shaving.Data collection and analysisTwo review authors independently assessed all potential studies for inclusion, assessed risk of bias and extracted the data using apredesigned form. Data were checked for accuracy.Main resultsThree randomised controlled trials (1039 women) published between 1922 and 2005 fulfilled the prespecified criteria. In the earliesttrial, 389 women were alternately allocated to receive either skin preparation and perineal shaving or clipping of vulval hair only. In thesecond trial, which included 150 participants, perineal shaving was compared with the cutting of long hairs for procedures only. In thethird and most recent trial, 500 women were randomly allocated to shaving of perineal area or cutting of perineal hair. The primaryoutcome for all three trials was maternal febrile morbidity; no differences were found (risk ratio (RR) 1.14, 95% confidence interval(CI) 0.73 to 1.76). No differences were found in terms of perineal wound infection (RR 1.47, 95% CI 0.80 to 2.70) and perinealwound dehiscence (RR 0.33, 95% CI 0.01 to 8.00) in the most recent trial involving 500 women, which was the only trial to assessthese outcomes. In the smallest trial, fewer women who had not been shaved had Gram-negative bacterial colonisation compared withwomen who had been shaved (RR 0.83, 95% CI 0.70 to 0.98). There were no instances of neonatal infection in either group in theone trial that reported this
NASA Astrophysics Data System (ADS)
Pan, Feifei; Stieglitz, Marc; McKane, Robert B.
2012-06-01
Digital elevation model (DEM) data are essential to hydrological applications and have been widely used to calculate a variety of useful topographic characteristics, e.g., slope, flow direction, flow accumulation area, stream channel network, topographic index, and others. Except for slope, none of the other topographic characteristics can be calculated until the flow direction at each pixel within a DEM is determined. However, flow direction cannot be accurately calculated until depressions and flat areas within a DEM have been rectified. This is a routine problem in hydrologic modeling, because virtually all DEMs contain flat and sink pixels, both real and artifactual, that if left untreated will prevent accurate simulation of hydrologic flow paths. Although a number of algorithms are available for rectifying flat and sink pixels in DEM data, treatment of flat areas and depressions and calculation of flow direction remain problematic for reasons of complexity and uncertainty. A new algorithm that effectively rectifies flat and sink pixels was developed and tested. The approach is to use linear interpolation between low elevation grid cells on the edge of each flat area or depression defined as outlets and higher elevation grid cells on the opposite side defined as inflow pixels. The implementation requires an iterative solution to accommodate the irregular geometry of flat areas or depressions and exceptions that arise. Linear interpolation across flat areas or depressions provides a natural way to scale elevation adjustments based on the vertical scale of the surrounding topography, thereby avoiding the addition or subtraction of arbitrary small numbers that we regard as a disadvantage in some prior techniques. Tests for two virtual terrains and one real terrain show that our algorithm effectively rectifies flat areas and depressions, even in low-relief terrain, and produces realistic patterns of flow accumulation and extracted channel networks.
NASA Technical Reports Server (NTRS)
Jones, William H.
1985-01-01
The Combined Aerodynamic and Structural Dynamic Problem Emulating Routines (CASPER) is a collection of data-base modification computer routines that can be used to simulate Navier-Stokes flow through realistic, time-varying internal flow fields. The Navier-Stokes equation used involves calculations in all three dimensions and retains all viscous terms. The only term neglected in the current implementation is gravitation. The solution approach is of an interative, time-marching nature. Calculations are based on Lagrangian aerodynamic elements (aeroelements). It is assumed that the relationships between a particular aeroelement and its five nearest neighbor aeroelements are sufficient to make a valid simulation of Navier-Stokes flow on a small scale and that the collection of all small-scale simulations makes a valid simulation of a large-scale flow. In keeping with these assumptions, it must be noted that CASPER produces an imitation or simulation of Navier-Stokes flow rather than a strict numerical solution of the Navier-Stokes equation. CASPER is written to operate under the Parallel, Asynchronous Executive (PAX), which is described in a separate report.
NASA Technical Reports Server (NTRS)
Purdon, David J.; Baruah, Pranab K.; Bussoletti, John E.; Epton, Michael A.; Massena, William A.; Nelson, Franklin D.; Tsurusaki, Kiyoharu
1990-01-01
The Maintenance Document Version 3.0 is a guide to the PAN AIR software system, a system which computes the subsonic or supersonic linear potential flow about a body of nearly arbitrary shape, using a higher order panel method. The document describes the overall system and each program module of the system. Sufficient detail is given for program maintenance, updating, and modification. It is assumed that the reader is familiar with programming and CRAY computer systems. The PAN AIR system was written in FORTRAN 4 language except for a few CAL language subroutines which exist in the PAN AIR library. Structured programming techniques were used to provide code documentation and maintainability. The operating systems accommodated are COS 1.11, COS 1.12, COS 1.13, and COS 1.14 on the CRAY 1S, 1M, and X-MP computing systems. The system is comprised of a data base management system, a program library, an execution control module, and nine separate FORTRAN technical modules. Each module calculates part of the posed PAN AIR problem. The data base manager is used to communicate between modules and within modules. The technical modules must be run in a prescribed fashion for each PAN AIR problem. In order to ease the problem of supplying the many JCL cards required to execute the modules, a set of CRAY procedures (PAPROCS) was created to automatically supply most of the JCL cards. Most of this document has not changed for Version 3.0. It now, however, strictly applies only to PAN AIR version 3.0. The major changes are: (1) additional sections covering the new FDP module (which calculates streamlines and offbody points); (2) a complete rewrite of the section on the MAG module; and (3) strict applicability to CRAY computing systems.
NASA Technical Reports Server (NTRS)
Baruah, P. K.; Bussoletti, J. E.; Chiang, D. T.; Massena, W. A.; Nelson, F. D.; Furdon, D. J.; Tsurusaki, K.
1981-01-01
The Maintenance Document is a guide to the PAN AIR software system, a system which computes the subsonic or supersonic linear potential flow about a body of nearly arbitrary shape, using a higher order panel method. The document describes the over-all system and each program module of the system. Sufficient detail is given for program maintenance, updating and modification. It is assumed that the reader is familiar with programming and CDC (Control Data Corporation) computer systems. The PAN AIR system was written in FORTRAN 4 language except for a few COMPASS language subroutines which exist in the PAN AIR library. Structured programming techniques were used to provide code documentation and maintainability. The operating systems accommodated are NOS 1.2, NOS/BE and SCOPE 2.1.3 on the CDC 6600, 7600 and Cyber 175 computing systems. The system is comprised of a data management system, a program library, an execution control module and nine separate FORTRAN technical modules. Each module calculates part of the posed PAN AIR problem. The data base manager is used to communicate between modules and within modules. The technical modules must be run in a prescribed fashion for each PAN AIR problem. In order to ease the problem of supplying the many JCL cards required to execute the modules, a separate module called MEC (Module Execution Control) was created to automatically supply most of the JCL cards. In addition to the MEC generated JCL, there is an additional set of user supplied JCL cards to initiate the JCL sequence stored on the system.
AKPLOT- A PLOTTER ROUTINE FOR THE IBM PC
NASA Technical Reports Server (NTRS)
Kantak, A. V.
1994-01-01
The AKPLOT routine was designed for engineers and scientists who use graphs as an integral part of their documentation. AKPLOT allows the user to generate a graph and edit its appearance on a CRT. This graph may undergo many interactive alterations before it is finally screen dumped to a printer for a hard copy plot. The finished AKPLOT graph may be stored in a file for future use. Features available in AKPLOT include: multiple curves on a single plot; combinations of linear and logarithmic scale axes; Lagrange interpolation of selected curves; shrink, expand, zoom, and tilt; ten different symbols and four different colors for curves; and three different grid types. AKPLOT enables the user to perform least squares fitting of all or selected curves with polynomials of up to 99 degrees and examine the least squares coefficients. The user must provide the data points to be plotted by one of two methods: 1) supplying an external file of X-Y values for all curves, or 2) computing the X-Y vectors by either placing BASIC code describing the relation in a designated section of the AKPLOT code or dynamically entering a one line function. Using either technique, the X-Y values are input to the computer only once, as the iterative graph edit loop bypasses the data input step for faster execution. AKPLOT is written in BASIC for interactive execution and has been implemented on an IBM PC series computer operating under DOS. AKPLOT requires a graphics board and a color monitor. This program was originally developed in 1986 and later revised in 1987.
BLAS- BASIC LINEAR ALGEBRA SUBPROGRAMS
NASA Technical Reports Server (NTRS)
Krogh, F. T.
1994-01-01
The Basic Linear Algebra Subprogram (BLAS) library is a collection of FORTRAN callable routines for employing standard techniques in performing the basic operations of numerical linear algebra. The BLAS library was developed to provide a portable and efficient source of basic operations for designers of programs involving linear algebraic computations. The subprograms available in the library cover the operations of dot product, multiplication of a scalar and a vector, vector plus a scalar times a vector, Givens transformation, modified Givens transformation, copy, swap, Euclidean norm, sum of magnitudes, and location of the largest magnitude element. Since these subprograms are to be used in an ANSI FORTRAN context, the cases of single precision, double precision, and complex data are provided for. All of the subprograms have been thoroughly tested and produce consistent results even when transported from machine to machine. BLAS contains Assembler versions and FORTRAN test code for any of the following compilers: Lahey F77L, Microsoft FORTRAN, or IBM Professional FORTRAN. It requires the Microsoft Macro Assembler and a math co-processor. The PC implementation allows individual arrays of over 64K. The BLAS library was developed in 1979. The PC version was made available in 1986 and updated in 1988.
Van Hertem, T; Parmet, Y; Steensels, M; Maltz, E; Antler, A; Schlageter-Tello, A A; Lokhorst, C; Romanini, C E B; Viazzi, S; Bahr, C; Berckmans, D; Halachmi, I
2014-01-01
The objective of this study was to quantify the effect of hoof trimming on cow behavior (ruminating time, activity, and locomotion score) and performance (milk yield) over time. Data were gathered from a commercial dairy farm in Israel where routine hoof trimming is done by a trained hoof trimmer twice per year on the entire herd. In total, 288 cows spread over 6 groups with varying production levels were used for the analysis. Cow behavior was measured continuously with a commercial neck activity logger and a ruminating time logger (HR-Tag, SCR Engineers Ltd., Netanya, Israel). Milk yield was recorded during each milking session with a commercial milk flow sensor (Free Flow, SCR Engineers Ltd.). A trained observer assigned on the spot 5-point locomotion scores during 19 nighttime milking occasions between 22 October 2012 and 4 February 2013. Behavioral and performance data were gathered from 1wk before hoof trimming until 1wk after hoof trimming. A generalized linear mixed model was used to statistically test all main and interactive effects of hoof trimming, parity, lactation stage, and hoof lesion presence on ruminating time, neck activity, milk yield, and locomotion score. The results on locomotion scores show that the proportional distribution of cows in the different locomotion score classes changes significantly after trimming. The proportion of cows with a locomotion score ≥3 increases from 14% before to 34% directly after the hoof trimming. Two months after the trimming, the number of cows with a locomotion score ≥3 reduced to 20%, which was still higher than the baseline values 2wk before the trimming. The neck activity level was significantly reduced 1d after trimming (380±6 bits/d) compared with before trimming (389±6 bits/d). Each one-unit increase in locomotion score reduced cow activity level by 4.488 bits/d. The effect of hoof trimming on ruminating time was affected by an interaction effect with parity. The effect of hoof trimming on
Recapturing Desired Family Routines: A Parent-Professional Behavioral Collaboration
ERIC Educational Resources Information Center
Buschbacher, Pamelazita; Fox, Lise; Clarke, Shelley
2004-01-01
Children with complex disabilities such as autism spectrum disorders and Landau Kleffner syndrome often lack means to participate in everyday family routines. Serious problem behaviors may result from their challenges in responding to and initiating communicative interactions. These behaviors can change routine family activities such that the…
Prescriptive Package. Improving Patrol Productivity. Volume I. Routine Patrol.
ERIC Educational Resources Information Center
Gay, William G.; Schack, Stephen
Designed to assist police departments in improving the productivity of their patrol operations, this volume on routine patrol and a companion volume on specialized patrol operations are intended for use by various sizes of departments. The volume on routine patrol focuses on the major issues of patrol productivity and recommends a number of…
See, Say, Write: A Writing Routine for the Preschool Classroom
ERIC Educational Resources Information Center
Copp, Stefanie B.; Cabell, Sonia Q.; Tortorelli, Laura S.
2016-01-01
See, Say, Write is an adaptable classroom writing routine that teachers can use across a range of activities in the preschool classroom. This preschool writing routine offers an opportunity for teachers to build on a shared experience through engagement in rich conversation and writing. After a shared experience, teachers will provide a visual…
An Element of Practical Knowledge in Education: Professional Routines
ERIC Educational Resources Information Center
Lacourse, France
2011-01-01
The question of practical knowledge and its teaching has arisen more perceptibly since the appearance of the aim to professionalize teachers. How can imperceptible knowledge such as professional routines be taught? To establish a social fabric and effective class management, it is essential to call on creative and adaptive professional routines.…
Helping Children Understand Routines and Classroom Schedules. What Works Briefs.
ERIC Educational Resources Information Center
Ostrosky, M. M.; Jung, E. Y.; Hemmeter, M. L.; Thomas, D.
Studies have documented that schedules and routines influence children's emotional, cognitive, and social development. Predictable and consistent schedules in preschool classrooms help children feel secure and comfortable. Also, schedules and routines help children understand the expectations of the environment and reduce the frequency of behavior…
32 CFR 1701.31 - General routine uses.
Code of Federal Regulations, 2011 CFR
2011-07-01
... relating to national intelligence or otherwise applicable to the ODNI. This routine use is not intended to... 32 National Defense 6 2011-07-01 2011-07-01 false General routine uses. 1701.31 Section 1701.31 National Defense Other Regulations Relating to National Defense OFFICE OF THE DIRECTOR OF...
32 CFR 1701.31 - General routine uses.
Code of Federal Regulations, 2013 CFR
2013-07-01
... relating to national intelligence or otherwise applicable to the ODNI. This routine use is not intended to... 32 National Defense 6 2013-07-01 2013-07-01 false General routine uses. 1701.31 Section 1701.31 National Defense Other Regulations Relating to National Defense OFFICE OF THE DIRECTOR OF...
Trait Routinization, Functional and Cognitive Status in Older Adults
ERIC Educational Resources Information Center
Zisberg, Anna; Zysberg, Leehu; Young, Heather M.; Schepp, Karen G.
2009-01-01
This study examined the associations between trait routinization and functional and cognitive as well as demographic indicators. A sample of American older adults living independently in a retirement community (n = 80) were assessed regarding their functional status, cognitive status, and preference for routine. Robust associations between…
32 CFR 1701.31 - General routine uses.
Code of Federal Regulations, 2014 CFR
2014-07-01
... INTELLIGENCE ADMINISTRATION OF RECORDS UNDER THE PRIVACY ACT OF 1974 Routine Uses Applicable to More Than One... of Congressional intelligence oversight committees in connection with the exercise of the committees... disclosed as a routine use pursuant to Executive Order to the President's Foreign Intelligence...
Thinking Routines: Replicating Classroom Practices within Museum Settings
ERIC Educational Resources Information Center
Wolberg, Rochelle Ibanez; Goff, Allison
2012-01-01
This article describes thinking routines as tools to guide and support young children's thinking. These learning strategies, developed by Harvard University's Project Zero Classroom, actively engage students in constructing meaning while also understanding their own thinking process. The authors discuss how thinking routines can be used in both…
Routines in School Organizations: Creating Stability and Change
ERIC Educational Resources Information Center
Conley, Sharon; Enomoto, Ernestine K.
2005-01-01
Purpose: This paper presents routinized action theory as a way to examine the regular, habitual activities that occur in school organizations. Using this theoretical lens, school routines were analyzed in order to understand organizational stability and change. Design/methodology/approach: Using case study methods, three discrete cases are…
The Association between Routinization and Cognitive Resources in Later Life
ERIC Educational Resources Information Center
Tournier, Isabelle; Mathey, Stephanie; Postal, Virginie
2012-01-01
The aim of this study was to investigate the association between routinization of daily life activities and cognitive resources during aging. Routinization could increase excessively during aging and become maladaptative in reducing individual resources. Fifty-two young participants (M = 20.8 years) and 62 older participants (M = 66.9 years)…
42 CFR 493.841 - Standard; Routine chemistry.
Code of Federal Regulations, 2011 CFR
2011-10-01
... 42 Public Health 5 2011-10-01 2011-10-01 false Standard; Routine chemistry. 493.841 Section 493.841 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN SERVICES... These Tests § 493.841 Standard; Routine chemistry. (a) Failure to attain a score of at least 80...
42 CFR 493.841 - Standard; Routine chemistry.
Code of Federal Regulations, 2010 CFR
2010-10-01
... 42 Public Health 5 2010-10-01 2010-10-01 false Standard; Routine chemistry. 493.841 Section 493.841 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN SERVICES... These Tests § 493.841 Standard; Routine chemistry. (a) Failure to attain a score of at least 80...
42 CFR 493.1267 - Standard: Routine chemistry.
Code of Federal Regulations, 2012 CFR
2012-10-01
... 42 Public Health 5 2012-10-01 2012-10-01 false Standard: Routine chemistry. 493.1267 Section 493.1267 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN SERVICES... Systems § 493.1267 Standard: Routine chemistry. For blood gas analyses, the laboratory must perform...
42 CFR 493.1267 - Standard: Routine chemistry.
Code of Federal Regulations, 2011 CFR
2011-10-01
... 42 Public Health 5 2011-10-01 2011-10-01 false Standard: Routine chemistry. 493.1267 Section 493.1267 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN SERVICES... Systems § 493.1267 Standard: Routine chemistry. For blood gas analyses, the laboratory must perform...
42 CFR 493.841 - Standard; Routine chemistry.
Code of Federal Regulations, 2013 CFR
2013-10-01
... 42 Public Health 5 2013-10-01 2013-10-01 false Standard; Routine chemistry. 493.841 Section 493.841 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN SERVICES... These Tests § 493.841 Standard; Routine chemistry. (a) Failure to attain a score of at least 80...
42 CFR 493.841 - Standard; Routine chemistry.
Code of Federal Regulations, 2014 CFR
2014-10-01
... 42 Public Health 5 2014-10-01 2014-10-01 false Standard; Routine chemistry. 493.841 Section 493.841 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN SERVICES... These Tests § 493.841 Standard; Routine chemistry. (a) Failure to attain a score of at least 80...
42 CFR 493.841 - Standard; Routine chemistry.
Code of Federal Regulations, 2012 CFR
2012-10-01
... 42 Public Health 5 2012-10-01 2012-10-01 false Standard; Routine chemistry. 493.841 Section 493.841 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN SERVICES... These Tests § 493.841 Standard; Routine chemistry. (a) Failure to attain a score of at least 80...
42 CFR 493.1267 - Standard: Routine chemistry.
Code of Federal Regulations, 2014 CFR
2014-10-01
... 42 Public Health 5 2014-10-01 2014-10-01 false Standard: Routine chemistry. 493.1267 Section 493.1267 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN SERVICES... Systems § 493.1267 Standard: Routine chemistry. For blood gas analyses, the laboratory must perform...
42 CFR 493.1267 - Standard: Routine chemistry.
Code of Federal Regulations, 2013 CFR
2013-10-01
... 42 Public Health 5 2013-10-01 2013-10-01 false Standard: Routine chemistry. 493.1267 Section 493.1267 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN SERVICES... Systems § 493.1267 Standard: Routine chemistry. For blood gas analyses, the laboratory must perform...
42 CFR 493.1267 - Standard: Routine chemistry.
Code of Federal Regulations, 2010 CFR
2010-10-01
... 42 Public Health 5 2010-10-01 2010-10-01 false Standard: Routine chemistry. 493.1267 Section 493.1267 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN SERVICES... Systems § 493.1267 Standard: Routine chemistry. For blood gas analyses, the laboratory must perform...
Factors for Radical Creativity, Incremental Creativity, and Routine, Noncreative Performance
ERIC Educational Resources Information Center
Madjar, Nora; Greenberg, Ellen; Chen, Zheng
2011-01-01
This study extends theory and research by differentiating between routine, noncreative performance and 2 distinct types of creativity: radical and incremental. We also use a sensemaking perspective to examine the interplay of social and personal factors that may influence a person's engagement in a certain level of creative action versus routine,…
Changing Urban Bureaucracies: How New Practices Become Routinized.
ERIC Educational Resources Information Center
Yin, Robert K.; And Others
The goal of this report is to describe the process by which new service practices in urban bureaucracies become routinized. The routinization process is studied by examining the life histories of six types of innovations: computer-assisted instruction; police computer systems; mobile intensive care units; closed circuit television systems; breath…
Parental Involvement Routines and Former Head Start Children's Literacy Outcomes
ERIC Educational Resources Information Center
Dove, Meghan Kicklighter; Neuharth-Pritchett, Stacey; Wright, David W.; Wallinga, Charlotte
2015-01-01
This study examined the relationship between parental involvement routines and former Head Start children's literacy outcomes. Former Head Start children (n = 3, 808) from the National Head Start/Public School Transition Demonstration Research Project comprised the sample. Family routines and literacy outcomes in kindergarten were examined,…
NASA Technical Reports Server (NTRS)
Medan, R. T. (Editor); Magnus, A. E.; Sidwell, K. W.; Epton, M. A.
1981-01-01
Numerous applications of the PAN AIR computer program system are presented. PAN AIR is user-oriented tool for analyzing and/or designing aerodynamic configurations in subsonic or supersonic flow using a technique generally referred to as a higher order panel method. Problems solved include simple wings in subsonic and supersonic flow, a wing-body in supersonic flow, wing with deflected flap in subsonic flow, design of two-dimensional and three-dimensional wings, axisymmetric nacelle in supersonic flow, and wing-canard-tail-nacelle-fuselage combination in supersonic flow.
User manual for two simple postscript output FORTRAN plotting routines
NASA Technical Reports Server (NTRS)
Nguyen, T. X.
1991-01-01
Graphics is one of the important tools in engineering analysis and design. However, plotting routines that generate output on high quality laser printers normally come in graphics packages, which tend to be expensive and system dependent. These factors become important for small computer systems or desktop computers, especially when only some form of a simple plotting routine is sufficient. With the Postscript language becoming popular, there are more and more Postscript laser printers now available. Simple, versatile, low cost plotting routines that can generate output on high quality laser printers are needed and standard FORTRAN language plotting routines using output in Postscript language seems logical. The purpose here is to explain two simple FORTRAN plotting routines that generate output in Postscript language.
Effectiveness and predictors of outcome in routine out-patient mental health care for older adults.
Veerbeek, Marjolein A; Oude Voshaar, Richard C; Pot, Anne Margriet
2014-04-23
ABSTRACT Background: Meta-analyses show efficacy of several psychological and pharmacological interventions for late-life psychiatric disorders, but generalization of effects to routine mental health care for older people remains unknown. Aim of this study is to investigate the improvement of functioning within one year of referral to an outpatient mental health clinic for older adults. Methods: Pre-post measurement of the Health of Nations Outcome Scale 65+ (HoNOS 65+) in 704 older people referred for psychiatric problems (no dementia) to any of the seven participating mental health care organizations. Results: The pre-post-test Cohen's d effect size was 1.08 in the total group and 1.23 in depressed patients, the largest subgroup. Linear regression identified better functioning at baseline, comorbid personality disorder, somatic comorbidity and life events during treatment as determinants of a worse outcome. Conclusions: Functioning of older persons with psychiatric problems largely improves after treatment in routine mental health care.
Linear baroclinic instability in the Martian atmosphere
NASA Astrophysics Data System (ADS)
Barnes, J. R.
1984-05-01
A spherical quasi-geostrophic model is used in an examination of linear baroclinic instability in such zonal-mean flows as those of the Martian atmosphere in winter, under both relatively nondusty and very dusty conditions. These zonal flows, which possess both vertical and meridional shear, are characterized by baroclinically unstable modes whose growth rates and phase speeds are generally consistent with available observations. The structures of the spherical modes are similar to those obtained for terrestrial zonal flows, if similar zonal wavelengths are compared. Zonally symmetric topography, like that of Mars' northern hemisphere, reduces linear growth rates without changing the most unstable scale. It also increases phase speeds.
Eating routines: Embedded, value based, modifiable, and reflective
Jastran, Margaret; Bisogni, Carole A.; Sobal, Jeffery; Blake, Christine; Devine, Carol M.
2009-01-01
Eating routines are a compelling issue because recurring eating behaviors influence nutrition and health. As non-traditional and individualized eating patterns have become more common, new ways of thinking about routine eating practices are needed. This study sought to gain conceptual understanding of working adults' eating routines. Forty-two purposively sampled US adults reported food intake and contextual details about eating episodes in qualitative 24-hour dietary recalls conducted over 7 consecutive days. Using the constant comparative method, researchers analyzed interview transcripts for recurrent ways of eating that were either explicitly reported by study participants as “routines” or emergent in the data. Participants' eating routines included repetition in food consumption as well as eating context, and also involved sequences of eating episodes. Eating routines were embedded in daily schedules for work, family, and recreation. Participants maintained purposeful routines that helped balance tension between demands and values, but they modified routines as circumstances changed. Participants monitored and reflected upon their eating practices and tended to assess their practices in light of their personal identities. These findings provide conceptual insights for food choice researchers and present a perspective from which practitioners who work with individuals seeking to adopt healthful eating practices might usefully approach their tasks. PMID:18835305
Ultra-high vacuum photoelectron linear accelerator
Yu, David U.L.; Luo, Yan
2013-07-16
An rf linear accelerator for producing an electron beam. The outer wall of the rf cavity of said linear accelerator being perforated to allow gas inside said rf cavity to flow to a pressure chamber surrounding said rf cavity and having means of ultra high vacuum pumping of the cathode of said rf linear accelerator. Said rf linear accelerator is used to accelerate polarized or unpolarized electrons produced by a photocathode, or to accelerate thermally heated electrons produced by a thermionic cathode, or to accelerate rf heated field emission electrons produced by a field emission cathode.
Calculation of vortex flows on complex configurations
NASA Technical Reports Server (NTRS)
Maskew, B.; Rao, B. M.
1982-01-01
The calculation of aerodynamic characteristics of complex configurations having strongly coupled vortex flows is a non-linear problem requiring iterative solution techniques. This paper discusses the use of a low-order panel method as a means of obtaining practical solutions to such problems. The panel method is based on piecewise constant source and doublet quadrilateral panels and uses the internal Dirichlet boundary condition of zero perturbation potential. The problems of predicting vortex/surface interaction and vortex separation are discussed. Some example calculations are included but further test cases have yet to be carried out, in particular for comparisons with experimental data. The problem of convergence on the iterative calculation for the shape of the free vortex sheet is addressed and a preprocessor routine, based on an unsteady, two-dimensional version of the panel method, is put forward as a cost-effective way of generating an initial vortex structure for use as a starting solution for general configurations.
Floating-point function generation routines for 16-bit microcomputers
NASA Technical Reports Server (NTRS)
Mackin, M. A.; Soeder, J. F.
1984-01-01
Several computer subroutines have been developed that interpolate three types of nonanalytic functions: univariate, bivariate, and map. The routines use data in floating-point form. However, because they are written for use on a 16-bit Intel 8086 system with an 8087 mathematical coprocessor, they execute as fast as routines using data in scaled integer form. Although all of the routines are written in assembly language, they have been implemented in a modular fashion so as to facilitate their use with high-level languages.
Factors for radical creativity, incremental creativity, and routine, noncreative performance.
Madjar, Nora; Greenberg, Ellen; Chen, Zheng
2011-07-01
This study extends theory and research by differentiating between routine, noncreative performance and 2 distinct types of creativity: radical and incremental. We also use a sensemaking perspective to examine the interplay of social and personal factors that may influence a person's engagement in a certain level of creative action versus routine, noncreative work. Results demonstrate that willingness to take risks, resources for creativity, and career commitment are associated primarily with radical creativity; that the presence of creative coworkers and organizational identification are associated with incremental creativity; and that conformity and organizational identification are linked with routine performance. Theoretical and managerial implications are discussed.
Testing calibration routines for LISFLOOD, a distributed hydrological model
NASA Astrophysics Data System (ADS)
Pannemans, B.
2009-04-01
Traditionally hydrological models are considered as difficult to calibrate: their highly non-linearity results in rugged and rough response surfaces were calibration algorithms easily get stuck in local minima. For the calibration of distributed hydrological models two extra factors play an important role: on the one hand they are often costly on computation, thus restricting the feasible number of model runs; on the other hand their distributed nature smooths the response surface, thus facilitating the search for a global minimum. Lisflood is a distributed hydrological model currently used for the European Flood Alert System - EFAS (Van der Knijff et al, 2008). Its upcoming recalibration over more then 200 catchments, each with an average runtime of 2-3 minutes, proved a perfect occasion to put several existing calibration algorithms to the test. The tested routines are Downhill Simplex (DHS, Nelder and Mead, 1965), SCEUA (Duan et Al. 1993), SCEM (Vrugt et al., 2003) and AMALGAM (Vrugt et al., 2008), and they were evaluated on their capability to efficiently converge onto the global minimum and on the spread in the found solutions in repeated runs. The routines were let loose on a simple hyperbolic function, on a Lisflood catchment using model output as observation, and on two Lisflood catchments using real observations (one on the river Inn in the Alps, the other along the downstream stretch of the Elbe). On the mathematical problem and on the catchment with synthetic observations DHS proved to be the fastest and the most efficient in finding a solution. SCEUA and AMALGAM are a slower, but while SCEUA keeps converging on the exact solution, AMALGAM slows down after about 600 runs. For the Lisflood models with real-time observations AMALGAM (hybrid algorithm that combines several other algorithms, we used CMA, PSO and GA) came as fastest out of the tests, and giving comparable results in consecutive runs. However, some more work is needed to tweak the stopping
Stolker, Alida A. M.; Peters, Ruud J. B.; Zuiderent, Richard; DiBussolo, Joseph M.
2010-01-01
There is an increasing interest in screening methods for quick and sensitive analysis of various classes of veterinary drugs with limited sample pre-treatment. Turbulent flow chromatography in combination with tandem mass spectrometry has been applied for the first time as an efficient screening method in routine analysis of milk samples. Eight veterinary drugs, belonging to seven different classes were selected for this study. After developing and optimising the method, parameters such as linearity, repeatability, matrix effects and carry-over were studied. The screening method was then tested in the routine analysis of 12 raw milk samples. Even without internal standards, the linearity of the method was found to be good in the concentration range of 50 to 500 µg/L. Regarding repeatability, RSDs below 12% were obtained for all analytes, with only a few exceptions. The limits of detection were between 0.1 and 5.2 µg/L, far below the maximum residue levels for milk set by the EU regulations. While matrix effects—ion suppression or enhancement—are obtained for all the analytes the method has proved to be useful for screening purposes because of its sensitivity, linearity and repeatability. Furthermore, when performing the routine analysis of the raw milk samples, no false positive or negative results were obtained. PMID:20379812
Thromboembolism Prophylaxis in Hip Arthroplasty: Routine and High Risk Patients.
Nam, Denis; Nunley, Ryan M; Johnson, Staci R; Keeney, James A; Clohisy, John C; Barrack, Robert L
2015-12-01
This study's purpose was to present the use of a risk stratification protocol in which "routine" risk patients receive a mobile compression device with aspirin and "high" risk patients receive warfarin for thromboprophylaxis after hip arthroplasty. 1859 hip arthroplasty patients were prospectively enrolled (1402 routine risk--75.4%, 457 high risk--24.6%). The cumulative rate of venous thromboembolism events was 0.5% in the routine versus 0.5% in the high-risk cohort within 6weeks postoperatively (P=1.00). Patients in the routine risk cohort had a lower rate of major bleeding (0.5% versus 2.0%, P=0.006) and wound complications (0.2% versus 1.2%, P=0.01). Use of our risk stratification protocol allowed the avoidance of more aggressive anticoagulation in 75% of patients while achieving a low overall incidence of symptomatic VTE. PMID:26182980
User's Manual: Routines for Radiative Heat Transfer and Thermometry
NASA Technical Reports Server (NTRS)
Risch, Timothy K.
2016-01-01
Determining the intensity and spectral distribution of radiation emanating from a heated surface has applications in many areas of science and engineering. Areas of research in which the quantification of spectral radiation is used routinely include thermal radiation heat transfer, infrared signature analysis, and radiation thermometry. In the analysis of radiation, it is helpful to be able to predict the radiative intensity and the spectral distribution of the emitted energy. Presented in this report is a set of routines written in Microsoft Visual Basic for Applications (VBA) (Microsoft Corporation, Redmond, Washington) and incorporating functions specific to Microsoft Excel (Microsoft Corporation, Redmond, Washington) that are useful for predicting the radiative behavior of heated surfaces. These routines include functions for calculating quantities of primary importance to engineers and scientists. In addition, the routines also provide the capability to use such information to determine surface temperatures from spectral intensities and for calculating the sensitivity of the surface temperature measurements to unknowns in the input parameters.
Unsupervised daily routine and activity discovery in smart homes.
Jie Yin; Qing Zhang; Karunanithi, Mohan
2015-08-01
The ability to accurately recognize daily activities of residents is a core premise of smart homes to assist with remote health monitoring. Most of the existing methods rely on a supervised model trained from a preselected and manually labeled set of activities, which are often time-consuming and costly to obtain in practice. In contrast, this paper presents an unsupervised method for discovering daily routines and activities for smart home residents. Our proposed method first uses a Markov chain to model a resident's locomotion patterns at different times of day and discover clusters of daily routines at the macro level. For each routine cluster, it then drills down to further discover room-level activities at the micro level. The automatic identification of daily routines and activities is useful for understanding indicators of functional decline of elderly people and suggesting timely interventions.
Routine Eye Exams See Vision Problems You Miss
... news/fullstory_159863.html Routine Eye Exams See Vision Problems You Miss Older people and those who ... half of people with no new symptoms or vision problems receive new prescriptions or treatment changes as ...
Radioxenon retention in the skeleton on a routine ventilation study
Kramer, E.L.; Tiu, S.; Sanger, J.J.; Benjamin, D.D.
1983-07-01
Marked retention of radioxenon by the skeletal structures during a routine ventilation scan is described. Xenon uptake by bones occurs largely in the intraosseous fat. Augmented uptake in this case may be related to the patient's prolonged steroid therapy.
Effects of preshot routine on free-throw shooting.
Gayton, W F; Cielinski, K L; Francis-Keniston, W J; Hearns, J F
1989-02-01
The effect of prohibiting the use of a preshot routine on free-throw shooting in competitive situations was investigated. 25 male high school basketball players were instructed to attempt 50 free throws alternating in blocks of 10 between the use of their preshot routine and shooting without it. To make the situation competitive, subjects were run in groups of five and their performance was recorded on a large easel placed to the side of the free-throw line. A significantly larger number of baskets were made in the preshot routine condition than without the routine. A competitive situation led to a greater decrement in baskets than had been reported in 1986 by Lobmeyer and Wassermen during noncompetitive free-throw shooting.
Survey of US Correctional Institutions for Routine HCV Testing.
Beckwith, Curt G; Kurth, Ann E; Bazerman, Lauri; Solomon, Liza; Patry, Emily; Rich, Josiah D; Kuo, Irene
2015-01-01
To ascertain HCV testing practices among US prisons and jails, we conducted a survey study in 2012, consisting of medical directors of all US state prisons and 40 of the largest US jails, that demonstrated a minority of US prisons and jails conduct routine HCV testing. Routine voluntary HCV testing in correctional facilities is urgently needed to increase diagnosis, enable risk-reduction counseling and preventive health care, and facilitate evaluation for antiviral treatment. PMID:25393180
Routine HIV Testing in Indiana Community Health Centers.
Meyerson, Beth E; Navale, Shalini M; Gillespie, Anthony; Ohmit, Anita
2015-01-01
Objectives. We assessed routine HIV testing in Indiana community health centers (CHCs). Methods. CHC medical directors reported HIV services, testing behaviors, barriers, and health center characteristics via survey from April to May 2013. Standard of care testing was measured by the extent to which CHCs complied with national guidelines for routine HIV testing in clinical settings. Results. Most (85.7%) CHCs reported HIV testing, primarily at patient request or if the patient was symptomatic. Routine HIV testing was provided for pregnant women by 60.7% of CHCs. Only 10.7% provided routine testing for adolescents to adults up to age 65 years. Routine testing was reported by 14.3% for gay and bisexual men, although 46.4% of CHCs reported asking patients about sexual orientation. Linkage to care services for HIV-positive patients, counseling for HIV treatment adherence, and partner testing generally was not provided. Conclusions. Most CHCs reported HIV testing, but such testing did not reflect the standard of care, because it depended on patient request or symptoms. One approach in future studies may be to allow respondents to compare current testing with standard of care and then reflect on barriers to and facilitators of adoption and implementation of routine HIV testing.
Work routinization and implications for ergonomic exposure assessment.
Gold, Judith E; Park, Jung-Soon; Punnett, Laura
2006-01-15
Jobs in many modern settings, including manufacturing, service, agriculture and construction, are variable in their content and timing. This prompts the need for exposure assessment methods that do not assume regular work cycles. A scheme is presented for classifying levels of routinization to inform development of an appropriate exposure assessment strategy for a given occupational setting. Five levels of routinization have been defined based on the tasks of which the job is composed: 1) a single scheduled task with a regular work cycle; 2) multiple cyclical tasks; 3) a mix of cyclical and non-cyclical tasks; 4) one non-cyclical task; 5) multiple non-cyclical tasks. This classification, based primarily on job observation, is illustrated through data from a study of automobile manufacturing workers (n = 1200), from which self-assessed exposures to physical and psychosocial stressors were also obtained. In this cohort, decision latitude was greater with higher routinization level (p < 0.0001), and the least routinized jobs showed the lowest self-reported exposure to physical ergonomic stressors. The job analysis checklist developed for non-routinized jobs is presented, and limitations of the task analysis method utilized in the study are discussed. A work sampling approach to job analysis is recommended as the most efficient way to obtain a comparable unbiased exposure estimate across all routinization levels. PMID:16393801
Work routinization and implications for ergonomic exposure assessment.
Gold, Judith E; Park, Jung-Soon; Punnett, Laura
2006-01-15
Jobs in many modern settings, including manufacturing, service, agriculture and construction, are variable in their content and timing. This prompts the need for exposure assessment methods that do not assume regular work cycles. A scheme is presented for classifying levels of routinization to inform development of an appropriate exposure assessment strategy for a given occupational setting. Five levels of routinization have been defined based on the tasks of which the job is composed: 1) a single scheduled task with a regular work cycle; 2) multiple cyclical tasks; 3) a mix of cyclical and non-cyclical tasks; 4) one non-cyclical task; 5) multiple non-cyclical tasks. This classification, based primarily on job observation, is illustrated through data from a study of automobile manufacturing workers (n = 1200), from which self-assessed exposures to physical and psychosocial stressors were also obtained. In this cohort, decision latitude was greater with higher routinization level (p < 0.0001), and the least routinized jobs showed the lowest self-reported exposure to physical ergonomic stressors. The job analysis checklist developed for non-routinized jobs is presented, and limitations of the task analysis method utilized in the study are discussed. A work sampling approach to job analysis is recommended as the most efficient way to obtain a comparable unbiased exposure estimate across all routinization levels.
2012-01-01
Introduction The Brief Symptom Inventory (BSI), Mood & Anxiety Symptom Questionnaire −30 (MASQ-D30), Short Form Health Survey 36 (SF-36), and Dimensional Assessment of Personality Pathology-Short Form (DAPP-SF) are generic instruments that can be used in Routine Outcome Monitoring (ROM) of patients with common mental disorders. We aimed to generate reference values usually encountered in 'healthy' and ‘psychiatrically ill’ populations to facilitate correct interpretation of ROM results. Methods We included the following specific reference populations: 1294 subjects from the general population (ROM reference group) recruited through general practitioners, and 5269 psychiatric outpatients diagnosed with mood, anxiety, or somatoform (MAS) disorders (ROM patient group). The outermost 5% of observations were used to define limits for one-sided reference intervals (95th percentiles for BSI, MASQ-D30 and DAPP-SF, and 5th percentiles for SF-36 subscales). Internal consistency and Receiver Operating Characteristics (ROC) analyses were performed. Results Mean age for the ROM reference group was 40.3 years (SD=12.6) and 37.7 years (SD=12.0) for the ROM patient group. The proportion of females was 62.8% and 64.6%, respectively. The mean for cut-off values of healthy individuals was 0.82 for the BSI subscales, 23 for the three MASQ-D30 subscales, 45 for the SF-36 subscales, and 3.1 for the DAPP-SF subscales. Discriminative power of the BSI, MASQ-D30 and SF-36 was good, but it was poor for the DAPP-SF. For all instruments, the internal consistency of the subscales ranged from adequate to excellent. Discussion and conclusion Reference values for the clinical interpretation were provided for the BSI, MASQ-D30, SF-36, and DAPP-SF. Clinical information aided by ROM data may represent the best means to appraise the clinical state of psychiatric outpatients. PMID:23171272
Relationships between ambient, cockpit, and pilot temperatures during routine air operations.
Harrison, M H; Higenbottam, C; Rigby, R A
1978-01-01
Thermal data obtained from aircraft flying routine sorties from RAF Germany in summer have been reduced to a form suitable for statistical analysis by describing thermal stress in terms of a modified wet bulb globe temperature (WBGT) index, and thermal strain in terms of mean body temperature (Tb). Ambient temperature could be related to cockpit temperature, and cockpit temperature to pilot Tb, by linear equations of positive slope. Relationships between Tb and sortie time could be represented by exponential equations. The relationships between cockpit temperature and sortie time could also, in fixed-wing aircraft, be described by exponential equations, although in helicopters the relationships were better described by linear equations of negative slope. Models capable of predicting cockpit thermal stress and aircrew thermal strain given ambient temperature and sortie time have been constructed. These provide a description of the temperature relationships within aircraft during flight.
Kabir, Khairul; Haidar, Azzam; Tomov, Stanimire; Dongarra, Jack J
2015-01-01
The manycore paradigm shift, and the resulting change in modern computer architectures, has made the development of optimal numerical routines extremely challenging. In this work, we target the development of numerical algorithms and implementations for Xeon Phi coprocessor architecture designs. In particular, we examine and optimize the general and symmetric matrix-vector multiplication routines (gemv/symv), which are some of the most heavily used linear algebra kernels in many important engineering and physics applications. We describe a successful approach on how to address the challenges for this problem, starting with our algorithm design, performance analysis and programing model and moving to kernel optimization. Our goal, by targeting low-level and easy to understand fundamental kernels, is to develop new optimization strategies that can be effective elsewhere for use on manycore coprocessors, and to show significant performance improvements compared to existing state-of-the-art implementations. Therefore, in addition to the new optimization strategies, analysis, and optimal performance results, we finally present the significance of using these routines/strategies to accelerate higher-level numerical algorithms for the eigenvalue problem (EVP) and the singular value decomposition (SVD) that by themselves are foundational for many important applications.
Honda, Takayuki; Tozuka, Minoru
2015-09-01
In the reversed clinicopathological conference (R-CPC), three specialists in laboratory medicine interpreted routine laboratory data independently in order to understand the detailed state of a patient. R-CPC is an educational method to use laboratory data appropriately, and it is also important to select differential diagnoses in a process of clinical reasoning in addition to the present illness and physical examination. Routine laboratory tests can be performed repeatedly at a relatively low cost, and their time-series analysis can be performed. Interpretation of routine laboratory data is almost the same as taking physical findings. General findings are initially checked and then the state of each organ is examined. Although routine laboratory tests cost little, we can gain much more information from them about the patient than physical examinations. PMID:26731894
Reticulocyte count using thiazole orange. A flow cytometry method.
Van Hove, L; Goossens, W; Van Duppen, V; Verwilghen, R L
1990-01-01
Recently flow cytometry techniques have been developed to replace the microscope reticulocyte count. We used thiazole orange, a RNA binding fluorochrome, to discriminate reticulocytes from mature erythrocytes. Thiazole orange and the Retic-COUNT software package were evaluated for performance of routine analysis on different flow instruments. The applied methodology analysed 10(4) cells semi-automatically in an easily performed manner. Consistent results were obtained with dipotassium EDTA anticoagulated blood (stable for 30 h after venesection), with incubation times in thiazole orange solution ranging from 2 to 7 h at 25 degrees C. This allowed flexibility in specimen collection and storage and assay performance with no change in results. Changes of incubation temperature up to 30 degrees C had no measurable effect. The values obtained showed good linearity, precision and accuracy for normal, low and high reticulocyte counts. However interferences were observed: RBC autofluorescence, nucleated RBC, Howell-Jolly bodies, high leucocyte count, high platelet count and giant platelets, all falsely increased the number of reticulocytes. These artifacts were eliminated by software gate corrections, thus leaving less than 5% of the specimen to be reanalysed by the microscopic method. The thiazole orange flow cytometric method was determined to be a fast, reliable method for the routine clinical quantitation of reticulocytes.
Efficient parallel architecture for highly coupled real-time linear system applications
NASA Technical Reports Server (NTRS)
Carroll, Chester C.; Homaifar, Abdollah; Barua, Soumavo
1988-01-01
A systematic procedure is developed for exploiting the parallel constructs of computation in a highly coupled, linear system application. An overall top-down design approach is adopted. Differential equations governing the application under consideration are partitioned into subtasks on the basis of a data flow analysis. The interconnected task units constitute a task graph which has to be computed in every update interval. Multiprocessing concepts utilizing parallel integration algorithms are then applied for efficient task graph execution. A simple scheduling routine is developed to handle task allocation while in the multiprocessor mode. Results of simulation and scheduling are compared on the basis of standard performance indices. Processor timing diagrams are developed on the basis of program output accruing to an optimal set of processors. Basic architectural attributes for implementing the system are discussed together with suggestions for processing element design. Emphasis is placed on flexible architectures capable of accommodating widely varying application specifics.
Electrothermal linear actuator
NASA Technical Reports Server (NTRS)
Derr, L. J.; Tobias, R. A.
1969-01-01
Converting electric power into powerful linear thrust without generation of magnetic fields is accomplished with an electrothermal linear actuator. When treated by an energized filament, a stack of bimetallic washers expands and drives the end of the shaft upward.
NASA Technical Reports Server (NTRS)
Tuey, R. C.
1972-01-01
Computer solutions of linear programming problems are outlined. Information covers vector spaces, convex sets, and matrix algebra elements for solving simultaneous linear equations. Dual problems, reduced cost analysis, ranges, and error analysis are illustrated.
Out-of-Core Solutions of Complex Sparse Linear Equations
NASA Technical Reports Server (NTRS)
Yip, E. L.
1982-01-01
ETCLIB is library of subroutines for obtaining out-of-core solutions of complex sparse linear equations. Routines apply to dense and sparse matrices too large to be stored in core. Useful for solving any set of linear equations, but particularly useful in cases where coefficient matrix has no special properties that guarantee convergence with any of interative processes. The only assumption made is that coefficient matrix is not singular.
Clinician's Attitudes to the Introduction of Routine Weighing in Pregnancy.
Hasted, Tim; Stapleton, Helen; Beckmann, Michael M; Wilkinson, Shelley A
2016-01-01
Background. Excessive gestational weight gain poses significant short- and long-term health risks to both mother and baby. Professional bodies and health services increasingly recommend greater attention be paid to weight gain in pregnancy. A large Australian tertiary maternity hospital plans to facilitate the (re)introduction of routine weighing of all women at every antenatal visit. Objective. To identify clinicians' perspectives of barriers and enablers to routinely weighing pregnant women and variations in current practice, knowledge, and attitudes between different staff groups. Method. Forty-four maternity staff from three professional groups were interviewed in four focus groups. Staff included midwives; medical staff; and dietitians. Transcripts underwent qualitative content analysis to identify and examine barriers and enablers to the routine weighing of women throughout pregnancy. Results. While most staff supported routine weighing, various concerns were raised. Issues included access to resources and staff; the ability to provide appropriate counselling and evidence-based interventions; and the impact of weighing on patients and the therapeutic relationship. Conclusion. Many clinicians supported the practice of routine weighing in pregnancy, but barriers were also identified. Implementation strategies will be tailored to the discrete professional groups and will address identified gaps in knowledge, resources, and clinician skills and confidence. PMID:27446614
EZVIDEO, FORTRAN graphics routines for the IBM AT
Patterson, M.R.; Holdeman, J.T.; Ward, R.C.; Jackson, W.L.
1989-10-01
A set of IBM PC-based FORTRAN plotting routines called EZVIDEO is described in this report. These routines are written in FORTRAN and can be called from FORTRAN programs. EZVIDEO simulates a subset of the well-known DISSPLA graphics calls and makes plots directly on the IBM AT display screen. Screen dumps can also be made to an attached LaserJet or Epson printer to make hard copy without using terminal emulators. More than forty DISSPLA calls are simulated by the EZVIDEO routines. Typical screen plots require about 10 seconds (s), and good hard copy of the screen image on a laser printer requires less than 2 minutes (min). This higher-resolution hard copy is adequate for most purposes because of the enhanced resolution of the screen in the EGA and VGA modes. These EZVIDEO routines give the IB, AT user a stand-alone capability to make useful scientific or engineering plots directly on the AT, using data generated in FORTRAN programs. The routines will also work on the IBM PC or XT in CGA mode, but they require more time and yield less resolution. 7 refs., 4 figs.
Clinician's Attitudes to the Introduction of Routine Weighing in Pregnancy
Beckmann, Michael M.; Wilkinson, Shelley A.
2016-01-01
Background. Excessive gestational weight gain poses significant short- and long-term health risks to both mother and baby. Professional bodies and health services increasingly recommend greater attention be paid to weight gain in pregnancy. A large Australian tertiary maternity hospital plans to facilitate the (re)introduction of routine weighing of all women at every antenatal visit. Objective. To identify clinicians' perspectives of barriers and enablers to routinely weighing pregnant women and variations in current practice, knowledge, and attitudes between different staff groups. Method. Forty-four maternity staff from three professional groups were interviewed in four focus groups. Staff included midwives; medical staff; and dietitians. Transcripts underwent qualitative content analysis to identify and examine barriers and enablers to the routine weighing of women throughout pregnancy. Results. While most staff supported routine weighing, various concerns were raised. Issues included access to resources and staff; the ability to provide appropriate counselling and evidence-based interventions; and the impact of weighing on patients and the therapeutic relationship. Conclusion. Many clinicians supported the practice of routine weighing in pregnancy, but barriers were also identified. Implementation strategies will be tailored to the discrete professional groups and will address identified gaps in knowledge, resources, and clinician skills and confidence. PMID:27446614
Klinger, Dane H; Dale, Jonathan J; Machado, Benjamin E; Incardona, John P; Farwell, Charles J; Block, Barbara A
2015-09-15
During the 2010 Deepwater Horizon incident, the continuous release of crude oil from the damaged Macondo 252 wellhead on the ocean floor contaminated surface water habitats for pelagic fish for more than 12weeks. The spill occurred across pelagic, neritic and benthic waters, impacting a variety of ecosystems. Chemical components of crude oil are known to disrupt cardiac function in juvenile fish, and here we investigate the effects of oil on the routine metabolic rate of chub mackerel, Scomber japonicus. Mackerel were exposed to artificially weathered Macondo 252 crude oil, prepared as a Water Accommodated Fraction (WAF), for 72 or 96h. Routine metabolic rates were determined pre- and post-exposure using an intermittent-flow, swim tunnel respirometer. Routine energetic demand increased in all mackerels in response to crude oil and reached statistical significance relative to unexposed controls at 96h. Chemical analyses of bile from exposed fish revealed elevated levels of fluorescent metabolites, confirming the bioavailability of polycyclic aromatic hydrocarbons (PAHs) in the exposure WAF. The observed increase in metabolic demand is likely attributable to the bioenergetic costs of contaminant detoxification. These results indicate that short-term exposure (i.e. days) to oil has sub-lethal toxicity to mackerel and results in physiological stress during the active spill phase of the incident. PMID:26210587
Klinger, Dane H; Dale, Jonathan J; Machado, Benjamin E; Incardona, John P; Farwell, Charles J; Block, Barbara A
2015-09-15
During the 2010 Deepwater Horizon incident, the continuous release of crude oil from the damaged Macondo 252 wellhead on the ocean floor contaminated surface water habitats for pelagic fish for more than 12weeks. The spill occurred across pelagic, neritic and benthic waters, impacting a variety of ecosystems. Chemical components of crude oil are known to disrupt cardiac function in juvenile fish, and here we investigate the effects of oil on the routine metabolic rate of chub mackerel, Scomber japonicus. Mackerel were exposed to artificially weathered Macondo 252 crude oil, prepared as a Water Accommodated Fraction (WAF), for 72 or 96h. Routine metabolic rates were determined pre- and post-exposure using an intermittent-flow, swim tunnel respirometer. Routine energetic demand increased in all mackerels in response to crude oil and reached statistical significance relative to unexposed controls at 96h. Chemical analyses of bile from exposed fish revealed elevated levels of fluorescent metabolites, confirming the bioavailability of polycyclic aromatic hydrocarbons (PAHs) in the exposure WAF. The observed increase in metabolic demand is likely attributable to the bioenergetic costs of contaminant detoxification. These results indicate that short-term exposure (i.e. days) to oil has sub-lethal toxicity to mackerel and results in physiological stress during the active spill phase of the incident.
A linear Fick's law calorimeter
NASA Astrophysics Data System (ADS)
Alpert, Seymour S.; Bryant, Pat D.; Woodside, William F.
1982-10-01
A small animal calorimeter is described that is based on the direct application of Fick's law. Heat flow is channeled through a circular disk of magnesium and the temperature difference between the inside and outside surface of the disk is detected by means of solid-state temperature transducers. The device is calibrated using a light-weight electrical resistive source and is shown to be linear in its response and to have an e-folding time of 4.8 min. A rat was introduced into the calorimeter and its heat energy expenditure rate was observed in both the sedated and unsedated states.
Drag reduction by a linear viscosity profile.
De Angelis, Elisabetta; Casciola, Carlo M; L'vov, Victor S; Pomyalov, Anna; Procaccia, Itamar; Tiberkevich, Vasil
2004-11-01
Drag reduction by polymers in turbulent flows raises an apparent contradiction: the stretching of the polymers must increase the viscosity, so why is the drag reduced? A recent theory proposed that drag reduction, in agreement with experiments, is consistent with the effective viscosity growing linearly with the distance from the wall. With this self-consistent solution the reduction in the Reynolds stress overwhelms the increase in viscous drag. In this Rapid Communication we show, using direct numerical simulations, that a linear viscosity profile indeed reduces the drag in agreement with the theory and in close correspondence with direct simulations of the FENE-P model at the same flow conditions.
Master schedule for CY-1982 Hanford environmental surveillance routine program
Blumer, P.J.; Sula, M.J.; Eddy, P.A.
1981-12-01
This report provides the current schedule of data collection for the routine environmental surveillance program at the Hanford Site. The environmental surveillance program objectives are to evaluate and report the levels of radioactive and nonradioactive pollutants in the Hanford environs, as required in DOE Order 5484.1. The routine sampling schedule provided does not include samples which are planned to be collected during FY-1982 in support of special studies or for quality control purposes. In addition, the routine program outlined in this schedule is subject to modification during the year in response to changes in Site operations, program requirements, or unusual sample results. Sampling schedules are presented for the following: air; Columbia River; sanitary water; surface water; ground water; foodstuffs; wildlife; soil and vegetation; external radiation measurements; portable instrument surveys; and surveillance of waste disposal sites. (ATT)
Routine Work Environment Stress and PTSD Symptoms in Police Officers
Maguen, Shira; Metzler, Thomas J.; McCaslin, Shannon E.; Inslicht, Sabra S.; Henn-Haase, Clare; Neylan, Thomas C.; Marmar, Charles R.
2013-01-01
This study examined the relationship between routine work environment stress and posttraumatic stress disorder (PTSD) symptoms in a sample of police officers (N = 180) who were first assessed during academy training and reassessed 1-year later. In a model that included gender, ethnicity, traumatic exposure prior to entering the academy, current negative life events, and critical incident exposure over the last year, routine work environment stress was most strongly associated with PTSD symptoms. We also found that routine work environment stress mediated the relationship between critical incident exposure and PTSD symptoms and between current negative life events and PTSD symptoms. Ensuring that the work environment is functioning optimally protects against the effects of duty-related critical incidents and negative life events outside police service. PMID:19829204
Evolution and function of routine trichromatic vision in primates.
Lucas, Peter W; Dominy, Nathaniel J; Riba-Hernandez, Pablo; Stoner, Kathryn E; Yamashita, Nayuta; Loría-Calderón, Esteban; Petersen-Pereira, Wanda; Rojas-Durán, Yahaira; Salas-Pena, Ruth; Solis-Madrigal, Silvia; Osorio, Daniel; Darvell, Brian W
2003-11-01
Evolution of the red-green visual subsystem in trichromatic primates has been linked to foraging advantages, namely the detection of either ripe fruits or young leaves amid mature foliage. We tested competing hypotheses globally for eight primate taxa: five with routine trichromatic vision, three without. Routinely trichromatic species ingested leaves that were "red shifted" compared to background foliage more frequently than species lacking this trait. Observed choices were not the reddest possible, suggesting a preference for optimal nutritive gain. There were no similar differences for fruits although red-greenness may sometimes be important in close-range fruit selection. These results suggest that routine trichromacy evolved in a context in which leaf consumption was critical.
Guide to good practices for shift routines and operating practices
1998-12-01
This Guide to Good Practices is written to enhance understanding of, and provide direction for, ``Shift Routines and Operating Practices,`` Chapter 2 of Department of Energy (DOE) Order 5480.19, Conduct of Operations Requirements for DOE Facilities. The practices in this guide should be considered when planning or reviewing shift routines and operating practices. ``Shift Routines and Operating Practices`` is an element of an effective Conduct of Operations program. The complexity and array of activities performed in DOE facilities dictate the necessity for a high standard of professional conduct and sound operating practices to promote safe and efficient operations. Recently, guidance pertaining to this element has been strengthened for nuclear power reactors. This additional guidance is given in Appendix C for information purposes. Though this guidance and good practices pertain to nuclear power reactors, DOE sites may choose to use a graded approach for implementing these in nuclear facilities.
Computer routines for probability distributions, random numbers, and related functions
Kirby, W.
1983-01-01
Use of previously coded and tested subroutines simplifies and speeds up program development and testing. This report presents routines that can be used to calculate various probability distributions and other functions of importance in statistical hydrology. The routines are designed as general-purpose Fortran subroutines and functions to be called from user-written main progress. The probability distributions provided include the beta, chi-square, gamma, Gaussian (normal), Pearson Type III (tables and approximation), and Weibull. Also provided are the distributions of the Grubbs-Beck outlier test, Kolmogorov 's and Smirnov 's D, Student 's t, noncentral t (approximate), and Snedecor F. Other mathematical functions include the Bessel function, I sub o, gamma and log-gamma functions, error functions, and exponential integral. Auxiliary services include sorting and printer-plotting. Random number generators for uniform and normal numbers are provided and may be used with some of the above routines to generate numbers from other distributions. (USGS)
Computer routines for probability distributions, random numbers, and related functions
Kirby, W.H.
1980-01-01
Use of previously codes and tested subroutines simplifies and speeds up program development and testing. This report presents routines that can be used to calculate various probability distributions and other functions of importance in statistical hydrology. The routines are designed as general-purpose Fortran subroutines and functions to be called from user-written main programs. The probability distributions provided include the beta, chisquare, gamma, Gaussian (normal), Pearson Type III (tables and approximation), and Weibull. Also provided are the distributions of the Grubbs-Beck outlier test, Kolmogorov 's and Smirnov 's D, Student 's t, noncentral t (approximate), and Snedecor F tests. Other mathematical functions include the Bessel function I (subzero), gamma and log-gamma functions, error functions and exponential integral. Auxiliary services include sorting and printer plotting. Random number generators for uniform and normal numbers are provided and may be used with some of the above routines to generate numbers from other distributions. (USGS)
Pulse processing routines for neutron time-of-flight data
NASA Astrophysics Data System (ADS)
Žugec, P.; Weiß, C.; Guerrero, C.; Gunsing, F.; Vlachoudis, V.; Sabate-Gilarte, M.; Stamatopoulos, A.; Wright, T.; Lerendegui-Marco, J.; Mingrone, F.; Ryan, J. A.; Warren, S. G.; Tsinganis, A.; Barbagallo, M.
2016-03-01
A pulse shape analysis framework is described, which was developed for n_TOF-Phase3, the third phase in the operation of the n_TOF facility at CERN. The most notable feature of this new framework is the adoption of generic pulse shape analysis routines, characterized by a minimal number of explicit assumptions about the nature of pulses. The aim of these routines is to be applicable to a wide variety of detectors, thus facilitating the introduction of the new detectors or types of detectors into the analysis framework. The operational details of the routines are suited to the specific requirements of particular detectors by adjusting the set of external input parameters. Pulse recognition, baseline calculation and the pulse shape fitting procedure are described. Special emphasis is put on their computational efficiency, since the most basic implementations of these conceptually simple methods are often computationally inefficient.
Exercise as part of a cystic fibrosis therapeutic routine.
Rand, Sarah; Prasad, S Ammani
2012-06-01
The role of exercise in cystic fibrosis (CF) is well established, and over the last three decades it has become an important component in the management of all individuals with CF. The role of exercise as a prognostic indicator or therapeutic tool is an important area of research interest in CF care internationally. This article summarizes the currently available evidence regarding exercise capacity in CF, the potential effects of exercise on health outcomes in CF and the challenges faced when trying to incorporate exercise into a CF therapeutic routine, and highlights some methods to facilitate the incorporation of exercise into CF therapeutic routines. PMID:22788948
Routine aymospheric correction of InSAR measurements of volcano surface deformations
NASA Astrophysics Data System (ADS)
Wadge, G.; Webley, P. W.; Stevens, N. F.
2003-04-01
The full potential of radar interferometry is limited by the effects of variable water vapour contents of the atmosphere. The problem is particularly noticeable over high relief volcanoes. Here we demonstrate a technique with the potential to routinely correct for the atmospheric path delay. We simulate the dynamic state of the three dimensional tropospheric flow around the volcano using a non-hydrostatic local model, initialised by ambient meteorological variables. This model simulates topographically-induced flow patterns on mountains. From the 3D model the radar-path delay field for each date can be modelled and the difference effect calculated. Using data from operational global circulation models to initialise the local model means that the technique can be used anywhere. We illustrate the approach using ERS InSAR data from the Etna volcano covering the 1995--2000 period. Correcting for the atmosphere reveals inter-eruption strain patterns that would otherwise be interpreted less correctly.
Wiedemann, H.
1981-11-01
Since no linear colliders have been built yet it is difficult to know at what energy the linear cost scaling of linear colliders drops below the quadratic scaling of storage rings. There is, however, no doubt that a linear collider facility for a center of mass energy above say 500 GeV is significantly cheaper than an equivalent storage ring. In order to make the linear collider principle feasible at very high energies a number of problems have to be solved. There are two kinds of problems: one which is related to the feasibility of the principle and the other kind of problems is associated with minimizing the cost of constructing and operating such a facility. This lecture series describes the problems and possible solutions. Since the real test of a principle requires the construction of a prototype I will in the last chapter describe the SLC project at the Stanford Linear Accelerator Center.
NASA Technical Reports Server (NTRS)
Holloway, Sidney E., III (Inventor); Crossley, Edward A., Jr. (Inventor); Jones, Irby W. (Inventor); Miller, James B. (Inventor); Davis, C. Calvin (Inventor); Behun, Vaughn D. (Inventor); Goodrich, Lewis R., Sr. (Inventor)
1992-01-01
A linear mass actuator includes an upper housing and a lower housing connectable to each other and having a central passageway passing axially through a mass that is linearly movable in the central passageway. Rollers mounted in the upper and lower housings in frictional engagement with the mass translate the mass linearly in the central passageway and drive motors operatively coupled to the roller means, for rotating the rollers and driving the mass axially in the central passageway.
Linear phase compressive filter
McEwan, Thomas E.
1995-01-01
A phase linear filter for soliton suppression is in the form of a laddered series of stages of non-commensurate low pass filters with each low pass filter having a series coupled inductance (L) and a reverse biased, voltage dependent varactor diode, to ground which acts as a variable capacitance (C). L and C values are set to levels which correspond to a linear or conventional phase linear filter. Inductance is mapped directly from that of an equivalent nonlinear transmission line and capacitance is mapped from the linear case using a large signal equivalent of a nonlinear transmission line.
Linear phase compressive filter
McEwan, T.E.
1995-06-06
A phase linear filter for soliton suppression is in the form of a laddered series of stages of non-commensurate low pass filters with each low pass filter having a series coupled inductance (L) and a reverse biased, voltage dependent varactor diode, to ground which acts as a variable capacitance (C). L and C values are set to levels which correspond to a linear or conventional phase linear filter. Inductance is mapped directly from that of an equivalent nonlinear transmission line and capacitance is mapped from the linear case using a large signal equivalent of a nonlinear transmission line. 2 figs.
Fault tolerant linear actuator
Tesar, Delbert
2004-09-14
In varying embodiments, the fault tolerant linear actuator of the present invention is a new and improved linear actuator with fault tolerance and positional control that may incorporate velocity summing, force summing, or a combination of the two. In one embodiment, the invention offers a velocity summing arrangement with a differential gear between two prime movers driving a cage, which then drives a linear spindle screw transmission. Other embodiments feature two prime movers driving separate linear spindle screw transmissions, one internal and one external, in a totally concentric and compact integrated module.
Flow distribution in selected branches of St. Clair and Detroit rivers
Holtschlag, D.J.; Koschik, J.A.
2002-01-01
St. Clair and Detroit rivers, which are connecting channels between Lake Huron and Lake Erie in the Great Lakes basin, form part of the boundary between the state of Michigan and the province of Ontario. In 13 reaches, this flow divides locally around islands and dikes to form 31 branches. This study develops a set of simple linear regression equations for computing expected flow proportions in branches, generally as a function of the total flow within the reach. The equations are based on 533 acoustic Doppler current profiler measurements of flow obtained between 1996 and 2000. Root-mean-square errors of these regressions range from 0.00323 to 0.0895. In seven upstream reaches where flow is known because of flow specifications at the boundaries of the waterway and continuity constraints, the uncertainties of the flow proportions can be used to directly infer the uncertainties of the corresponding flows. In six downstream reaches, the uncertainties of flows are determined by both the uncertainties of the flow proportions and the uncertainties of the total flow in the reach. For these reaches, Monte Carlo simulations quantify the ratios of total uncertainty to flow proportion uncertainty, which range from 1.0026 to 13.984. To facilitate routine calculation, polynomial regression equations are developed to approximate these ratios as a function of flow. Results provide a mechanism for computing the magnitudes and uncertainties of steady-state flows within selected branches of the connecting channels by specifying inflows at the headwaters of St. Clair River, seven intervening tributaries, and Lake St. Clair.
A routine, automated synthesis of oxygen-15-labeled butanol for positron tomography
Berridge, M.S.; Cassidy, E.H.; Terris, A.H. )
1990-10-01
The use of labeled butanol for autoradiographic and positron tomographic measurement of cerebral blood flow has been well established using radiocarbon labels. The advantages of the short half-life of oxygen-15 ({sup 15}O) in doing sequential flow studies are also recognized. An automated procedure has been developed for the routine rapid and sequential synthesis of {sup 15}O-labeled butanol in amounts and with purity suitable for use in positron tomography. Butanol can now replace {sup 15}O-labeled water, which is commonly used for routine applications. The 14N(d,n){sup 15}O reaction is used, with 8 MeV deuterons on a nitrogen target containing 0.2% oxygen. Labeled oxygen is reacted with tri-n-butyl-borane by passing the gas over an alumina support which holds the reagent. Washing with water through small C18-bonded phase silica cartridges eliminates labeled water and the majority of boron-containing impurities. Injectable labeled butanol is collected at 2.5 min after the end of bombardment. The yield is 6 mCi per microampere of saturated bombardment, measured at the end of synthesis. Injectable product up to 250 mCi can be obtained at 10-min intervals.
Jones, Blake L; Fiese, Barbara H
2014-01-01
Many daily routines and behaviors are related to the prevalence of obesity. This study investigated the association between routines and behaviors that act as protective factors related to lower prevalence of obesity in parents (BMI ≥ 30 kg/m(2)) and overweight in preschool children (BMI ≥ 85th percentile). Socio-demographic characteristics were assessed in relation to protective routines (PRs), and prevalence of obesity/overweight data from 337 preschool children and their parents. The two PRs assessed with parents included adequate sleep (≥7 h/night) and family mealtime routine (scoring higher than the median score). The four PRs assessed in children included adequate sleep (≥10 h/night), family mealtime routine, limiting screen-viewing time (≤2 h/day of TV, video, DVD), and not having a bedroom TV. Overall, 27.9% of parents were obese and 22.8% of children were overweight, and 39.8% of the parents had both parent PRs, and only 11.6% of children had all four child PRs. Results demonstrated that several demographic factors were significantly related to the use of PRs for parents and children. The lack of PRs was related to increased risk for overweight in children, but not for obesity in parents. However, in the adjusted models the overall cumulative benefits of using PRs was not significant in children either. In the multivariate adjusted logistic regression models, the only significant individual PR for children was adequate sleep. In a path analysis model, parent sleep was related to child sleep, which was in turn related to decreased obesity. Overall, findings suggest that parent and child PRs, especially sleep routines, within a family can be associated and may play an important role in the health outcomes of both parents and children. Understanding the mechanisms that influence how and when parents and children use these PRs may be promising for developing targeted family-based obesity-prevention efforts.
Jones, Blake L; Fiese, Barbara H
2014-01-01
Many daily routines and behaviors are related to the prevalence of obesity. This study investigated the association between routines and behaviors that act as protective factors related to lower prevalence of obesity in parents (BMI ≥ 30 kg/m(2)) and overweight in preschool children (BMI ≥ 85th percentile). Socio-demographic characteristics were assessed in relation to protective routines (PRs), and prevalence of obesity/overweight data from 337 preschool children and their parents. The two PRs assessed with parents included adequate sleep (≥7 h/night) and family mealtime routine (scoring higher than the median score). The four PRs assessed in children included adequate sleep (≥10 h/night), family mealtime routine, limiting screen-viewing time (≤2 h/day of TV, video, DVD), and not having a bedroom TV. Overall, 27.9% of parents were obese and 22.8% of children were overweight, and 39.8% of the parents had both parent PRs, and only 11.6% of children had all four child PRs. Results demonstrated that several demographic factors were significantly related to the use of PRs for parents and children. The lack of PRs was related to increased risk for overweight in children, but not for obesity in parents. However, in the adjusted models the overall cumulative benefits of using PRs was not significant in children either. In the multivariate adjusted logistic regression models, the only significant individual PR for children was adequate sleep. In a path analysis model, parent sleep was related to child sleep, which was in turn related to decreased obesity. Overall, findings suggest that parent and child PRs, especially sleep routines, within a family can be associated and may play an important role in the health outcomes of both parents and children. Understanding the mechanisms that influence how and when parents and children use these PRs may be promising for developing targeted family-based obesity-prevention efforts. PMID:24808883
Back to Schooling: Challenging Implicit Routines and Change
ERIC Educational Resources Information Center
Gorodetsky, Malka; Barak, Judith
2009-01-01
Engestrom and others have suggested that major barriers towards school change are rooted in the hidden, implicit aspects of daily school life that are taken for granted. These constitute the school's taken-for-granted routines, which mold teachers' affordances and constraints within the school, without their awareness. The present paper provides…
Nonanalytic function generation routines for 16-bit microprocessors
NASA Technical Reports Server (NTRS)
Soeder, J. F.; Shaufl, M.
1980-01-01
Interpolation techniques for three types (univariate, bivariate, and map) of nonanalytic functions are described. These interpolation techniques are then implemented in scaled fraction arithmetic on a representative 16 bit microprocessor. A FORTRAN program is described that facilitates the scaling, documentation, and organization of data for use by these routines. Listings of all these programs are included in an appendix.
Routines, Roles, and Responsibilities for Aligning Scientific and Classroom Practices
ERIC Educational Resources Information Center
Ford, Michael J.; Wargo, Brian M.
2007-01-01
Reform efforts in science education have focused on engaging students in authentic scientific practices. For these efforts to succeed, detailed articulations of scientific practice need to be linked to understandings of classroom practice. Here we characterize engagement in practice generally in terms of "3Rs": routines, roles, and…
Creating Masterpieces: How Course Structures and Routines Enable Student Performance
ERIC Educational Resources Information Center
Dean, Kathy Lund; Fornaciari, Charles J.
2014-01-01
Over a five-year period, we made a persistent observation: Course structures and routines, such as assignment parameters, student group process rules, and grading schemes were being consistently ignored. As a result, we got distracted by correcting these structural issues and were spending less time on student assignment performance. In this…
32 CFR 318.14 - Blanket routine uses.
Code of Federal Regulations, 2011 CFR
2011-07-01
... interest of simplicity, economy and to avoid redundancy. (b) Routine Use—Law Enforcement. If a system of... to the OMB in connection with the review of private relief legislation as set forth in OMB Circular A-19 at any stage of the legislative coordination and clearance process as set forth in that...
32 CFR 318.14 - Blanket routine uses.
Code of Federal Regulations, 2013 CFR
2013-07-01
... interest of simplicity, economy and to avoid redundancy. (b) Routine Use—Law Enforcement. If a system of... to the OMB in connection with the review of private relief legislation as set forth in OMB Circular A-19 at any stage of the legislative coordination and clearance process as set forth in that...
32 CFR 318.14 - Blanket routine uses.
Code of Federal Regulations, 2012 CFR
2012-07-01
... interest of simplicity, economy and to avoid redundancy. (b) Routine Use—Law Enforcement. If a system of... to the OMB in connection with the review of private relief legislation as set forth in OMB Circular A-19 at any stage of the legislative coordination and clearance process as set forth in that...
32 CFR 318.14 - Blanket routine uses.
Code of Federal Regulations, 2010 CFR
2010-07-01
... interest of simplicity, economy and to avoid redundancy. (b) Routine Use—Law Enforcement. If a system of... to the OMB in connection with the review of private relief legislation as set forth in OMB Circular A-19 at any stage of the legislative coordination and clearance process as set forth in that...
32 CFR 318.14 - Blanket routine uses.
Code of Federal Regulations, 2014 CFR
2014-07-01
... interest of simplicity, economy and to avoid redundancy. (b) Routine Use—Law Enforcement. If a system of... to the OMB in connection with the review of private relief legislation as set forth in OMB Circular A-19 at any stage of the legislative coordination and clearance process as set forth in that...
Increasing Day Care Staff Members' Interactions during Caregiving Routines.
ERIC Educational Resources Information Center
Venn, Martha L.; Wolery, Mark
1992-01-01
Four paraprofessional staff members in a mainstreamed day care program were trained to engage in positive interactive behaviors during diaper changing. Results indicated that staff increased frequency of game playing and other interactive behaviors during diapering, but increases were not generalized to feeding routines. (Author/JDD)
Bipolar deep brain stimulation permits routine EKG, EEG, and polysomnography.
Frysinger, Robert C; Quigg, Mark; Elias, W Jeffrey
2006-01-24
As the population of patients treated with deep brain stimulation (DBS) grows and the patients age, more will require routine or emergent electrophysiologic tests. DBS artifact may render these uninterpretable, whereas stopping DBS may release symptoms that confound evaluation. The authors find that monopolar, but not bipolar, stimulation produces significant artifact during EKG, EEG, and polysomnography.
Infant/Toddler Caregiving: A Guide to Routines. Second Edition.
ERIC Educational Resources Information Center
Gonzalez-Mena, Janet
Intended for use in conjunction with videos illustrating key concepts and caregiving techniques, this guide focuses on how the daily routines of caring for infants and toddlers can become opportunities for promoting the child's learning and development and for deepening the relationship between child and caregiver. Special attention is given to…
Rasch Analysis of the Routines-Based Interview Implementation Checklist
ERIC Educational Resources Information Center
Boavida, Tânia; Akers, Kate; McWilliam, R. A.; Jung, Lee Ann
2015-01-01
The Routines-Based Interview (RBI) is useful for developing functional outcomes/goals, for establishing strong relationships with families, and for assessing the family's true needs. In this study, the authors investigated the psychometric properties of the RBI Implementation Checklist, conducted by 120 early intervention professionals,…
"Your Eye Is Sparkling": Formulaic Expressions and Routines in Turkish.
ERIC Educational Resources Information Center
Dogancay, Seran
There are certain pre-coded (formulaic) utterances conventionally triggered by certain communication situations, and their use is expected and deemed appropriate because they are seen as part of everyday politeness formulas. Lack of an English equivalent indicates cultural differences governing their use. Some routines are taught explicitly and…
Daily Routines and Sleep Disorders in Visually Impaired Children.
ERIC Educational Resources Information Center
Troster, Heinrich; And Others
1996-01-01
Assessed sleep disorders in 265 visually impaired and 67 non-disabled 10- to 72-month olds. Found that infants with visual impairments had more difficulties in falling asleep and in sleeping through the night than nonhandicapped children. Also found a relationship between sleep disorders and the regularity of children's daily routine and…
The free routine postcatheterization urogram: a cost/benefit analysis
Waldman, J.D.; Kaplan, G.W.; Rummerfield, P.S.; Gilpin, E.A.; Kirkpatrick, S.E.
1982-01-01
Postangiography urography has become routine procedure in most centers performing cardiac catheterization in children. We analyzed the x-radiation dosage and clinical yield of this procedure. Using lithium fluoride thermoluminescent dosimeters, radiation exposure to the abdomen and gonads was measured in 35 children during postangiography urography. Results of 334 consecutive routine postangiography cine-urograms were evaluated based on clinical significance and compared to previous reports on this subject. Average absorbed abdominal radiation dosage was 241 mR +/- 240 from cine-urography, 16 mR +/- 13 from fluoroscopy, and 107 mR +/- 111 from a single abdominal roentgenogram. Gonadal dosage averaged 8 mR and was uniformly less than 27 mR. Of 334 routine postangiography cineurograms, 282 (84%) were normal, 30 (9%) were technically inadequate, 12 (3%) had abnormalities that were clinically insignificant or were falsely positive and in 10 (3%), clinically significant urologic conditions were confirmed. Because of the low yield of clinically significant anomalies and the added radiation exposure, we no longer perform routine postangiography cine-urography in children. Following cardiac angiography, the upper renal collecting systems are examined fluoroscopically. If abnormalities are suspected or fluoroscopy is equivocal, a single abdominal roentgenogram is performed. Using this procedure, mean average absorbed abdominal radiation dose can be reduced from 241 mR to 30.5 mR.
Supporting Classroom Transitions between Daily Routines: Strategies and Tips
ERIC Educational Resources Information Center
Banerjee, Rashida; Horn, Eva
2013-01-01
The purpose of this article is to provide tools for preschool professionals to plan for transitions between daily routines, to identify challenging transitions during the day, and to offer strategies to support transitions in classrooms to prevent challenging behaviors from occurring due to frequent changes. Specifically, the authors answer three…
Matrix algebra routines for the Acorn Archimedes microcomputer: example applications.
Fielding, A
1988-08-01
A set of matrix algebra routines have been written, as BASICV procedures, for the Acorn Archimedes microcomputer. It is shown that these procedures are executed so quickly that programs, which require matrix algebra computations, can be written in interpreted BASIC. Two example applications, reciprocal averaging and principal components analysis, are demonstrated.
School Bus Crash Rates on Routine and Nonroutine Routes
ERIC Educational Resources Information Center
O'Neal, Elizabeth; Ramirez, Marizen; Hamann, Cara; Young, Tracy; Stahlhut, Mary; Peek-Asa, Corinne
2014-01-01
Background: Although prior research has established that school buses are a safe form of transportation, crashes can produce catastrophic consequences. School buses have 2 types of routes: predictable, routine routes that take children to and from school and less predictable, nonroutine routes for school events. No studies have examined school bus…
Rethinking the Hidden Curriculum: Daily Routine in Slovene Preschools
ERIC Educational Resources Information Center
Zorec, Marcela Batistic; Došler, Anita Jug
2016-01-01
In Slovenia there is a unitary system of early education for all preschool-aged children. Since the vast majority of children attend full-day programmes, the daily routine represents a significant part of life for children in kindergarten. When systemic and curricular reform of preschools was introduced at the end of the twentieth century, lot of…
Routine Activities and Sexual Harassment in the Workplace.
ERIC Educational Resources Information Center
De Coster, Stacy; Estes, Sarah Beth; Mueller, Charles W.
1999-01-01
In criminology, routine activities of potential victims can be used to predict victimization. Application to organizational sexual harassment data shows that organizational features (proximity in job location, supervisor or work group guardianship) and individual characteristics (target attractiveness) can predict sexual harassment victimization,…
Cervical discospondylitis in 2 Great Dane puppies following routine surgery
Finnen, Andrea; Blond, Laurent; Parent, Joane
2012-01-01
Two Great Dane puppies developed cervical discospondylitis following routine surgery for sterilization. One animal was affected at C4–C5 and the other at C6–C7 intervertebral discs. Pseudomonas aeruginosa was obtained in pure culture from ultrasound-guided disc aspiration in 1 case. Both animals were successfully treated with long-term antibiotics. PMID:23115366
42 CFR 414.220 - Inexpensive or routinely purchased items.
Code of Federal Regulations, 2010 CFR
2010-10-01
... 42 Public Health 3 2010-10-01 2010-10-01 false Inexpensive or routinely purchased items. 414.220 Section 414.220 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICARE PROGRAM PAYMENT FOR PART B MEDICAL AND OTHER HEALTH SERVICES Payment...
The case for routine maintenance of dental implants.
Wilson, Thomas G; Valderrama, Pilar; Rodrigues, Danieli B C
2014-05-01
The large majority of dental implants are successful over the long term. Failure is usually associated with infection, trauma, inflammation, or a combination of these factors. Early identification and appropriate treatment can identify and eliminate these problems in the majority of cases. Thus routine implant maintenance structured along the guidelines for patients with periodontal diseases is recommended.
The Effect of Instruction on Pragmatic Routines in Academic Discussion
ERIC Educational Resources Information Center
Bardovi-Harlig, Kathleen; Mossman, Sabrina; Vellenga, Heidi E.
2015-01-01
This study investigates the effect of instruction on the acquisition of pragmatic routines used in academic discussion, specifically expressions of agreement, disagreement, and clarification. Thirty-seven learners, including an experimental group of 26 students and a control group of 11 students, participated in the study. Five intact classes…
42 CFR 414.220 - Inexpensive or routinely purchased items.
Code of Federal Regulations, 2011 CFR
2011-10-01
... SERVICES (CONTINUED) MEDICARE PROGRAM PAYMENT FOR PART B MEDICAL AND OTHER HEALTH SERVICES Payment for Durable Medical Equipment and Prosthetic and Orthotic Devices § 414.220 Inexpensive or routinely purchased... in conjunction with a nebulizer, aspirator, or ventilator excluded from § 414.222 meet...
Optimization of Routine Monitoring of Workers Exposed to Plutonium Aerosols.
Davesne, Estelle; Quesne, Benoit; De Vita, Antoine; Chojnacki, Eric; Blanchardon, Eric; Franck, Didier
2016-10-01
In case of incidental confinement failure, mixed oxide (MOX) fuel preparation may expose workers to plutonium aerosols. Due to its potential toxicity, occupational exposure to plutonium compounds should be kept as low as reasonably achievable. To ensure the absence of significant intake of radionuclides, workers at risk of internal contamination are monitored by periodic bioassay planned in a routine monitoring programme. From bioassay results, internal dose may be estimated. However, accurate dose calculation relies on known exposure conditions, which are rarely available when the exposure is demonstrated by routine monitoring only. Therefore, internal dose calculation is subject to uncertainty from unknown exposure conditions and from activity measurement variability. The present study calculates the minimum detectable dose (MDD) for a routine monitoring programme by considering all plausible conditions of exposure and measurement uncertainty. The MDD evaluates the monitoring quality and can be used for optimization. Here, MDDs were calculated for the monitoring of workers preparing MOX fuel. Uncertain parameters were modelled by probability distributions defined according to information provided by experts of routine monitoring, of workplace radiological protection and of bioassay analysis. Results show that the current monitoring is well adapted to potential exposure. A sensitivity study of MDD highlights high dependence on exposure condition modelling. Integrating all expert knowledge is therefore crucial to obtain reliable MDD estimates, stressing the value of a holistic approach to worker monitoring.
32 CFR 1701.31 - General routine uses.
Code of Federal Regulations, 2010 CFR
2010-07-01
... program statute, regulation, rule or order issued pursuant thereto, may be disclosed as a routine use to... affected information or information technology systems or programs (whether or not belonging to the ODNI... performing authorized responsibilities relating to terrorism or counterterrorism. (s) A record from a...
Developing Corpus-Based Materials to Teach Pragmatic Routines
ERIC Educational Resources Information Center
Bardovi-Harlig, Kathleen; Mossman, Sabrina; Vellenga, Heidi E.
2015-01-01
This article describes how to develop teaching materials for pragmatics based on authentic language by using a spoken corpus. The authors show how to use the corpus in conjunction with textbooks to identify pragmatic routines for speech acts and how to extract appropriate language samples and adapt them for classroom use. They demonstrate how to…
Cost effectiveness of routine duodenal biopsies in iron deficiency anemia
Broide, Efrat; Matalon, Shay; Kriger-Sharabi, Ofra; Richter, Vered; Shirin, Haim; Leshno, Moshe
2016-01-01
AIM To investigate the cost effectiveness of routine small bowel biopsies (SBBs) in patients with iron deficiency anemia (IDA) independent of their celiac disease (CD) serology test results. METHODS We used a state transition Markov model. Two strategies were compared: routine SBBs during esophagogastroduodenoscopy (EGD) in all patients with IDA regardless their celiac serology status (strategy A) vs SBBs only in IDA patients with positive serology (strategy B). The main outcomes were quality adjusted life years (QALY), average cost and the incremental cost effectiveness ratio (ICER). One way sensitivity analysis was performed on all variables and two way sensitivity analysis on selected variables were done. In order to validate the results, a Monte Carlo simulation of 100 sample trials with 10, and an acceptability curve were performed. RESULTS Strategy A of routine SBBs yielded 19.888 QALYs with a cost of $218.10 compared to 19.887 QALYs and $234.17 in strategy B. In terms of cost-effectiveness, strategy A was the dominant strategy, as long as the cost of SBBs stayed less than $67. In addition, the ICER of strategy A was preferable, providing the cost of biopsy stays under $77. Monte Carlo simulation demonstrated that strategy A yielded the same QALY but with lower costs than strategy B. CONCLUSION Our model suggests that EGD with routine SBBs is a cost-effective approach with improved QALYs in patients with IDA when the prevalence of CD is 5% or greater. SBBs should be a routine screening tool for CD among patients with IDA, regardless of their celiac antibody status. PMID:27678365
Cost effectiveness of routine duodenal biopsies in iron deficiency anemia
Broide, Efrat; Matalon, Shay; Kriger-Sharabi, Ofra; Richter, Vered; Shirin, Haim; Leshno, Moshe
2016-01-01
AIM To investigate the cost effectiveness of routine small bowel biopsies (SBBs) in patients with iron deficiency anemia (IDA) independent of their celiac disease (CD) serology test results. METHODS We used a state transition Markov model. Two strategies were compared: routine SBBs during esophagogastroduodenoscopy (EGD) in all patients with IDA regardless their celiac serology status (strategy A) vs SBBs only in IDA patients with positive serology (strategy B). The main outcomes were quality adjusted life years (QALY), average cost and the incremental cost effectiveness ratio (ICER). One way sensitivity analysis was performed on all variables and two way sensitivity analysis on selected variables were done. In order to validate the results, a Monte Carlo simulation of 100 sample trials with 10, and an acceptability curve were performed. RESULTS Strategy A of routine SBBs yielded 19.888 QALYs with a cost of $218.10 compared to 19.887 QALYs and $234.17 in strategy B. In terms of cost-effectiveness, strategy A was the dominant strategy, as long as the cost of SBBs stayed less than $67. In addition, the ICER of strategy A was preferable, providing the cost of biopsy stays under $77. Monte Carlo simulation demonstrated that strategy A yielded the same QALY but with lower costs than strategy B. CONCLUSION Our model suggests that EGD with routine SBBs is a cost-effective approach with improved QALYs in patients with IDA when the prevalence of CD is 5% or greater. SBBs should be a routine screening tool for CD among patients with IDA, regardless of their celiac antibody status.
Summary of cerebrospinal fluid routine parameters in neurodegenerative diseases.
Jesse, Sarah; Brettschneider, Johannes; Süssmuth, Sigurd D; Landwehrmeyer, Bernhard G; von Arnim, Christine A F; Ludolph, Albert C; Tumani, Hayrettin; Otto, Markus
2011-06-01
In neurodegenerative diseases, cerebrospinal fluid analysis (CSF) is predominantly performed to exclude inflammatory diseases and to perform a risk assessment in dementive disorders by measurement of tau proteins and amyloid beta peptides. However, large scale data on basic findings of CSF routine parameters are generally lacking. The objective of the study was to define a normal reference spectrum of routine CSF parameters in neurodegenerative diseases. Routine CSF parameters (white cell count, lactate and albumin concentrations, CSF/serum quotients of albumin (Q (alb)), IgG, IgA, IgM, and oligoclonal IgG bands (OCB)) were retrospectively analyzed in an academic research setting. A total of 765 patients (Alzheimer's disease (AD), Parkinson's disease (PD), Parkinson's disease dementia (PDD), vascular dementia (VD), frontotemporal lobar degeneration (FTLD), progressive supranuclear palsy (PSP), multisystem atrophy (MSA), motor neuron diseases (MND), spinocerebellar ataxia (SCA), Huntington's disease (HD)) and non-demented control groups including a group of patients with muscular disorders (MD). The main outcome measures included statistical analyses of routine CSF parameters. Mildly elevated Q (alb) were found in a small percentage of nearly all subgroups and in a higher proportion of patients with PSP, MSA, VD, PDD, and MND. With the exception of 1 MND patient, no intrathecal Ig synthesis was observed. Isolated OCBs in CSF were sometimes found in patients with neurodegenerative diseases without elevated cell counts; lactate levels were always normal. A slightly elevated Q (alb) was observed in a subgroup of patients with neurodegenerative diseases and does not exclude the diagnosis. Extensive elevation of routine parameters is not characteristic and should encourage a re-evaluation of the clinical diagnosis.
Holtschlag, D.J.; Koschik, J.A.
2001-01-01
St. Clair and Detroit Rivers are connecting channels between Lake Huron and Lake Erie in the Great Lakes waterway, and form part of the boundary between the United States and Canada. St. Clair River, the upper connecting channel, drains 222,400 square miles and has an average flow of about 182,000 cubic feet per second. Water from St. Clair River combines with local inflows and discharges into Lake St. Clair before flowing into Detroit River. In some reaches of St. Clair and Detroit Rivers, islands and dikes split the flow into two to four branches. Even when the flow in a reach is known, proportions of flows within individual branches of a reach are uncertain. Simple linear regression equations, subject to a flow continuity constraint, are developed to provide estimators of these proportions and flows. The equations are based on 533 paired measurements of flow in 13 reaches forming 31 branches. The equations provide a means for computing the expected values and uncertainties of steady-state flows on the basis of flow conditions specified at the upstream boundaries of the waterway. In 7 upstream reaches, flow is considered fixed because it can be determined on the basis of flows specified at waterway boundaries and flow continuity. In these reaches, the uncertainties of flow proportions indicated by the regression equations can be used directly to determine the uncertainties of the corresponding flows. In the remaining 6 downstream reaches, flow is considered uncertain because these reaches do not receive flow from all the branches of an upstream reach, or they receive flow from some branches of more than one upstream reach. Monte Carlo simulation analysis is used to quantify this increase in uncertainty associated with the propagation of uncertainties from upstream reaches to downstream reaches. To eliminate the need for Monte Carlo simulations for routine calculations, polynomial regression equations are developed to approximate the variation in uncertainties as
Film flow of a suspension down an inclined plane.
Li, Xiaofan; Pozrikidis, C
2003-05-15
A method is developed for simulating the film flow of a suspension of rigid particles with arbitrary shapes down an inclined plane in the limit of vanishing Reynolds number. The problem is formulated in terms of a system of integral equations of the first and second kind for the free-surface velocity and the traction distribution along the particle surfaces involving the a priori unknown particle linear velocity of translation and angular velocity of rotation about designated centres. The problem statement is completed by introducing scalar constraints that specify the force and torque exerted on the individual particles. A boundary-element method is implemented for solving the governing equations for the case of a two-dimensional periodic suspension. The system of linear equations arising from numerical discretization is solved using a preconditioner based on a particle-cluster iterative method recently developed by Pozrikidis (2000 Engng Analysis Bound. Elem. 25, 19-30). Numerical investigations show that the generalized minimal residual (GMRES) method with this preconditioner is significantly more efficient than the plain GMRES method used routinely in boundary-element implementations. Extensive numerical simulations for solitary particles and random suspensions illustrate the effect of the particle shape, size and aspect ratio in semi-finite shear flow, and the effect of free-surface deformability in film flow.
Linearly polarized fiber amplifier
Kliner, Dahv A.; Koplow, Jeffery P.
2004-11-30
Optically pumped rare-earth-doped polarizing fibers exhibit significantly higher gain for one linear polarization state than for the orthogonal state. Such a fiber can be used to construct a single-polarization fiber laser, amplifier, or amplified-spontaneous-emission (ASE) source without the need for additional optical components to obtain stable, linearly polarized operation.
Richter, B.
1985-12-01
A report is given on the goals and progress of the SLAC Linear Collider. The status of the machine and the detectors are discussed and an overview is given of the physics which can be done at this new facility. Some ideas on how (and why) large linear colliders of the future should be built are given.
NASA Technical Reports Server (NTRS)
Clancy, John P.
1988-01-01
The object of the invention is to provide a mechanical force actuator which is lightweight and manipulatable and utilizes linear motion for push or pull forces while maintaining a constant overall length. The mechanical force producing mechanism comprises a linear actuator mechanism and a linear motion shaft mounted parallel to one another. The linear motion shaft is connected to a stationary or fixed housing and to a movable housing where the movable housing is mechanically actuated through actuator mechanism by either manual means or motor means. The housings are adapted to releasably receive a variety of jaw or pulling elements adapted for clamping or prying action. The stationary housing is adapted to be pivotally mounted to permit an angular position of the housing to allow the tool to adapt to skewed interfaces. The actuator mechanisms is operated by a gear train to obtain linear motion of the actuator mechanism.
Linear models: permutation methods
Cade, B.S.; Everitt, B.S.; Howell, D.C.
2005-01-01
Permutation tests (see Permutation Based Inference) for the linear model have applications in behavioral studies when traditional parametric assumptions about the error term in a linear model are not tenable. Improved validity of Type I error rates can be achieved with properly constructed permutation tests. Perhaps more importantly, increased statistical power, improved robustness to effects of outliers, and detection of alternative distributional differences can be achieved by coupling permutation inference with alternative linear model estimators. For example, it is well-known that estimates of the mean in linear model are extremely sensitive to even a single outlying value of the dependent variable compared to estimates of the median [7, 19]. Traditionally, linear modeling focused on estimating changes in the center of distributions (means or medians). However, quantile regression allows distributional changes to be estimated in all or any selected part of a distribution or responses, providing a more complete statistical picture that has relevance to many biological questions [6]...
Effects of time and movements of the preshot routine on free throw shooting.
Mack, M G
2001-10-01
This study examined the effects of length and movements of preshot routines on free throw shooting in basketball. 17 members of an intercollegiate men's basketball team attempted 20 free throws in each of four different conditions: (1) normal routine and time, (2) normal routine with altered time, (3) altered routine with normal time, and (4) altered routine with altered time. Free throw performance was measured using an objective 5-point scoring system. A multivariate analysis of variance indicated a significant effect for routine. Neither time nor routine by time was significant. Results indicated that altering the movements in the routine had a significant effect on performance while lengthening the time did not.
System interaction with linear and nonlinear characteristics
Lin, C.W. ); Tseng, W.S. )
1991-01-01
This book is covered under some of the following topics: seismic margins in piping systems, vibrational power flow in a cylindrical shell, inelastic pipework dynamics and aseismic design, an efficient method for dynamic analysis of a linearly elastic piping system with nonlinear supports.
NASA Technical Reports Server (NTRS)
Studer, P. A. (Inventor)
1983-01-01
A linear magnetic bearing system having electromagnetic vernier flux paths in shunt relation with permanent magnets, so that the vernier flux does not traverse the permanent magnet, is described. Novelty is believed to reside in providing a linear magnetic bearing having electromagnetic flux paths that bypass high reluctance permanent magnets. Particular novelty is believed to reside in providing a linear magnetic bearing with a pair of axially spaced elements having electromagnets for establishing vernier x and y axis control. The magnetic bearing system has possible use in connection with a long life reciprocating cryogenic refrigerator that may be used on the space shuttle.
Master schedule for CY-1981 Hanford environmental surveillance routine program
Blumer, P.J.; Sula, M.J.; Eddy, P.A.
1980-12-01
The current schedule of data collection for the routine environmental surveillance program at the Hanford Site is provided. Questions about specific entries should be referred to the authors since modifications to the schedule are made during the year and special areas of study, usually of short duration, are not scheduled. The environmental surveillance program objectives are to evaluate the levels of radioactive and nonradioactive pollutants in the Hanford environs, as required in Manual Chapter 0513, and to monitor Hanford operations for compliance with applicable environmental criteria given in Manual Chapter 0524 and Washington State Water Quality Standards. Air quality data obtained in a separate program are also reported. The collection schedule for potable water is shown but it is not part of the routine environmental surveillance program. Schedules are presented for the following subjects: air, Columbia River, sanitary water, surface water, ground water, foodstuffs, wildlife, soil and vegetation, external radiation measurement, portable instrument surveys, and surveillance of waste disposal sites. (JGB)
Routine health check-ups: A boon or a burden?
Honnekeri, Bianca; Vyas, Aniruddha; Lokhandwala, Disha; Vaishnav, Avani; Vaishnav, Aditi; Singhal, Mayank; Barwad, Parag; Panicker, Gopi Krishna; Lokhandwala, Yash
2016-01-01
Healthcare provider institutions in India now offer structured health check-up 'packages' for routine screening of common diseases. While some tests included within their ambit are in keeping with international and Indian recommendations, some are entirely unwarranted. Unnecessary and inappropriate screening tests may cause more harm than benefit. Besides financial and resource burden, there may be over-diagnosis and over-treatment, psychological distress due to false-positive test results, harm from invasive follow-up tests, and false reassurance due to false-negative test results. Clinicians must ensure a net benefit from tests and interventions in order to efficiently deliver preventive services. We reviewed current screening guidelines for cardiovascular disease and common cancers, and surveyed multiple 'packages' provided at 8 centres in Mumbai, India. We put forth our recommendations for routine health screening in asymptomatic adults in India. PMID:27492031
CERES: Collection of Extraction Routines for Echelle Spectra
NASA Astrophysics Data System (ADS)
Brahm, Rafael; Jordán, Andrés; Espinoza, Néstor
2016-10-01
The Collection of Extraction Routines for Echelle Spectra (CERES) constructs automated pipelines for the reduction, extraction, and analysis of echelle spectrograph data. This modular code includes tools for handling the different steps of the processing: CCD reductions, tracing of the echelle orders, optimal and simple extraction, computation of the wave-length solution, estimation of radial velocities, and rough and fast estimation of the atmospheric parameters. The standard output of pipelines constructed with CERES is a FITS cube with the optimally extracted, wavelength calibrated and instrumental drift-corrected spectrum for each of the science images. Additionally, CERES includes routines for the computation of precise radial velocities and bisector spans via the cross-correlation method, and an automated algorithm to obtain an estimate of the atmospheric parameters of the observed star.
Past radionuclide releases from routine operations at Rocky Flats.
Ripple, S R; Widner, T E; Mongan, T R
1996-10-01
The Colorado Department of Public Health and Environment sponsored a study to reconstruct contaminant doses to the public from operations at the Rocky Flats nuclear weapons facility. This analysis of routine releases of plutonium and uranium, the principal radioactive materials used at the plant, was part of the Colorado Department of Public Health and Environment study. Historical radionuclide monitoring and data handling practices are characterized and uncertainties are quantified. Estimates of the annual release of plutonium and uranium are provided for the period from 1953 to 1989. Off-site airborne concentrations and deposition of plutonium and uranium associated with the releases are estimated, along with the highest doses for off-site populations. The predicted effective doses from the routine release of plutonium and uranium from Rocky Flats for a person residing near the plant boundary between 1953 and 1989 are very small. PMID:8830751
Differential absorption lidar system for routine monitoring of tropospheric ozone.
Sunesson, J A; Apituley, A; Swart, D P
1994-10-20
A differential absorption lidar system for routine profiling of tropospheric ozone for daytime and nighttime operation is described. The system uses stimulated Raman scattering in hydrogen and deuterium of 266-nm radiation from a quadrupled Nd:YAG laser. Ozone profiles from altitudes of 600 m to approximately 5 km have been obtained with analog detection. Implementing corrections for differential Rayleigh scattering, differential absorption from oxygen, sulphur dioxide, and nitrogen dioxide, and differential aerosol extinction and backscatter can reduce the total system inaccuracy to 5-15% for a clear day and 20-30% for a hazy day, except at the top of the mixed layer. Photon counting must be installed to increase the measurement range from 5 to 15 km. An example of an application of routine measurements of tropospheric ozone profiles is given.
Analysis of routine communication in the air traffic control system
NASA Technical Reports Server (NTRS)
Clark, Herbert H.; Morrow, Daniel; Rodvoid, Michelle
1990-01-01
The present project has three related goals. The first is to describe the organization of routine controller-pilot communication. This includes identifying the basic units of communication and how they are organized into discourse, how controllers and pilots use language to achieve their goals, and what topics they discuss. The second goal is to identify the type and frequency of problems that interrupt routine information transfer and prompt pilots and controllers to focus on the communication itself. The authors analyze the costs of these problems in terms of communication efficiency, and the techniques used to resolve these problems. Third, the authors hope to identify factors associated with communication problems, such as deviations from conventional air traffic control procedures.
Cryogenic Neutron Protein Crystallography: routine methods and potential benefits
Weiss, Kevin L; Tomanicek, Stephen J; NG, Joseph D
2014-01-01
The use of cryocooling in neutron diffraction has been hampered by several technical challenges such as the need for specialized equipment and techniques. Recently we have developed and deployed equipment and strategies that allow for routine neutron data collection on cryocooled crystals using off the shelf components. This system has several advantages, compared to a closed displex cooling system such as fast cooling coupled with easier crystal mounting and centering. The ability to routinely collect cryogenic neutron data for analysis will significantly broaden the range of scientific questions that can be examined by neutron protein crystallography. Cryogenic neutron data collection for macromolecules has recently become available at the new Biological Diffractometer BIODIFF at FRM II and the Macromolecular Diffractometer (MaNDi) at the Spallation Neutron Source, Oak Ridge National Laboratory. To evaluate the benefits of a cryocooled neutron structure we collected a full neutron data set on the BIODIFF instrument on a Toho-1 lactamase structure at 100K.
Economic benefits of a routine second dose of combined measles, mumps and rubella vaccine in Canada
Rivière, Marc; Tretiak, Roma; Levinton, Carey; Fitzsimon, Catherine; Leclerc, Caroline
1997-01-01
OBJECTIVE: To evaluate the potential economic benefits of a program for a second routine dose of combined measles, mumps and rubella (MMR) vaccine, administered to children in Canada. DESIGN: Both published and unpublished data from the United States and Canada were incorporated into a linear model. This information was supplemented with opinions on probability and resource use from interviews with a Canadian panel of physicians and practitioners. The province of Quebec was used as a model for resource use and costs. MATERIAL AND METHODS: Data were based on a vaccination program for Canadian children at 18 months, with an estimated annual birth cohort of 400,000. Further data were also collected for the lifetime costs of complications arising from these diseases or from vaccination, for both patients and family caregivers. OUTCOME MEASURES: Outcomes were reviewed from the perspectives of a provincial ministry of health (direct medical costs) and of society (all direct and indirect medical and nonmedical costs). RESULTS: It was estimated that a second dose of MMR vaccine administered at 18 months of age would prevent 9200 cases of measles, 6120 cases of mumps and 1960 cases of rubella, producing a savings of $6.34 for every dollar spent from the ministry of health perspective, and $3.25 from the societal perspective. CONCLUSIONS: A routine second dose immunization with MMR vaccine would result in considerable cost savings in Canada. PMID:22346520
Changing the game: exploring infants' participation in early play routines.
Fantasia, Valentina; Fasulo, Alessandra; Costall, Alan; López, Beatriz
2014-01-01
Play has proved to have a central role in children's development, most notably in rule learning (Piaget, 1965; Sutton-Smith, 1979) and negotiation of roles and goals (Garvey, 1974; Bruner et al., 1976). Yet very little research has been done on early play. The present study focuses on early social games, i.e., vocal-kinetic play routines that mothers use to interact with infants from very early on. We explored 3-month-old infants and their mothers performing a routine game first in the usual way, then in two violated conditions: without gestures and without sound. The aim of the study is to investigate infants' participation and expectations in the game and whether this participation is affected by changes in the multimodal format of the game. Infants' facial expressions, gaze, and body movements were coded to measure levels of engagement and affective state across the three conditions. Results showed a significant decrease in Limbs Movements and expressions of Positive Affect, an increase in Gaze Away and in Stunned Expression when the game structure was violated. These results indicate that the violated game conditions were experienced as less engaging, either because of an unexpected break in the established joint routine, or simply because they were weaker versions of the same game. Overall, our results suggest that structured, multimodal play routines may constitute interactional contexts that only work as integrated units of auditory and motor resources, representing early communicative contexts which prepare the ground for later, more complex multimodal interactions, such as verbal exchanges. PMID:24936192
Vectorizing the interpolation routines of particle-in-cell codes
Horowitz, E.J.
1987-01-01
A discussion of the interpolation routines in particle-in-cell codes is presented indicating the problems in vectorizing them. Solutions to these problems are then discussed with the timing results indicating the effectiveness of the solutions. A comparison of our methods to those of Nishiguchi et al. (J. Comput. Phys. 61, 519 (1985)) is presented. Finally, multitasking is briefly addressed. copyright 1987 Academic Press, Inc.
Getting through to circadian oscillators: why use constant routines?
NASA Technical Reports Server (NTRS)
Duffy, Jeanne F.; Dijk, Derk-Jan
2002-01-01
Overt 24-h rhythmicity is composed of both exogenous and endogenous components, reflecting the product of multiple (periodic) feedback loops with a core pacemaker at their center. Researchers attempting to reveal the endogenous circadian (near 24-h) component of rhythms commonly conduct their experiments under constant environmental conditions. However, even under constant environmental conditions, rhythmic changes in behavior, such as food intake or the sleep-wake cycle, can contribute to observed rhythmicity in many physiological and endocrine variables. Assessment of characteristics of the core circadian pacemaker and its direct contribution to rhythmicity in different variables, including rhythmicity in gene expression, may be more reliable when such periodic behaviors are eliminated or kept constant across all circadian phases. This is relevant for the assessment of the status of the circadian pacemaker in situations in which the sleep-wake cycle or food intake regimes are altered because of external conditions, such as in shift work or jet lag. It is also relevant for situations in which differences in overt rhythmicity could be due to changes in either sleep oscillatory processes or circadian rhythmicity, such as advanced or delayed sleep phase syndromes, in aging, or in particular clinical conditions. Researchers studying human circadian rhythms have developed constant routine protocols to assess the status of the circadian pacemaker in constant behavioral and environmental conditions, whereas this technique is often thought to be unnecessary in the study of animal rhythms. In this short review, the authors summarize constant routine methodology and what has been learned from constant routines and argue that animal and human circadian rhythm researchers should (continue to) use constant routines as a step on the road to getting through to central and peripheral circadian oscillators in the intact organism.
C-statistic fitting routines: User's manual and reference guide
NASA Technical Reports Server (NTRS)
Nousek, John A.; Farwana, Vida
1991-01-01
The computer program is discussed which can read several input files and provide a best set of values for the functions provided by the user, using either C-statistic or the chi(exp 2) statistic method. The program consists of one main routine and several functions and subroutines. Detail descriptions of each function and subroutine is presented. A brief description of the C-statistic and the reason for its application is also presented.
Changing the game: exploring infants' participation in early play routines
Fantasia, Valentina; Fasulo, Alessandra; Costall, Alan; López, Beatriz
2014-01-01
Play has proved to have a central role in children's development, most notably in rule learning (Piaget, 1965; Sutton-Smith, 1979) and negotiation of roles and goals (Garvey, 1974; Bruner et al., 1976). Yet very little research has been done on early play. The present study focuses on early social games, i.e., vocal-kinetic play routines that mothers use to interact with infants from very early on. We explored 3-month-old infants and their mothers performing a routine game first in the usual way, then in two violated conditions: without gestures and without sound. The aim of the study is to investigate infants' participation and expectations in the game and whether this participation is affected by changes in the multimodal format of the game. Infants' facial expressions, gaze, and body movements were coded to measure levels of engagement and affective state across the three conditions. Results showed a significant decrease in Limbs Movements and expressions of Positive Affect, an increase in Gaze Away and in Stunned Expression when the game structure was violated. These results indicate that the violated game conditions were experienced as less engaging, either because of an unexpected break in the established joint routine, or simply because they were weaker versions of the same game. Overall, our results suggest that structured, multimodal play routines may constitute interactional contexts that only work as integrated units of auditory and motor resources, representing early communicative contexts which prepare the ground for later, more complex multimodal interactions, such as verbal exchanges. PMID:24936192
Overview of mutation assays in transgenic mice for routine testing.
Gorelick, N J
1995-01-01
There is scientific and regulatory interest in using mutation assays in transgenic mice in safety assessments for new chemicals and drugs. Currently these assays are in the process of being validated, and protocols for routine testing are being defined. Some of the issues and results to date with regard to assay validation include reproducibility of the assay results (they are qualitatively reproducible), relevance of the test system (the transgene closely approximates an endogenous mammalian gene as a mutational target for the limited number of compounds tested), and the predictivity of the assay for heritable effects (unknown at this time) or carcinogenicity (the assays show good positive predictivity for carcinogenicity; the negative predictivity of the assay requires further investigation). Definition of appropriate study protocols for routine testing requires that applicable statistical methods are available and that the experimental parameters that affect the detection of mutations are known. Progress made in identifying these parameters is discussed. A proposal is made for the custom design of routine safety studies, which is based on the anticipated use of each individual test agent. A working group has been formed to conduct some of the studies still required for validation of these assays.
The effect of routine steam autoclaving on orthodontic pliers.
Jones, M; Pizarro, K; Blunden, R
1993-08-01
Five commonly used types of orthodontic plier of similar design, but different manufacture were evaluated for wear and corrosion following a 6-month regime of routine use in a hospital department together with steam autoclaving in a centralized unit. Three different types of manufacture (metal finish) were evaluated: (1) a stainless steel plier; (2) a chrome plated plier; and (3) a cheaper chrome plated plier. Four identical kits for changing archwires were assembled for each of the three manufacture types. A sixth 'plier', always of chrome plated manufacture (group 2) was added to every kit and acted as an additional control. In all, 72 pliers were evaluated by three observers immediately before and after the trial. Visual analogue and rank scales were used to assess corrosion, damage, the efficiency of the plier, etc. Generally, all of the pliers stood up well to a combination of routine clinical use and steam autoclaving; however, the stainless steel pliers appeared to perform the best. It is likely that the most important factor, when setting up this type of sterilizing method for orthodontic instruments, is to establish a careful and meticulous routine for cleaning, lubricating, and steam autoclaving pliers.
Identifying visual stress during a routine eye examination
Monger, Laura; Wilkins, Arnold; Allen, Peter
2014-01-01
Purpose To investigate whether the clinical tests used in routine eye examinations can identify adults whose reading rate increases with their preferred coloured overlay(s). Methods Routine optometric tests were used to measure 73 undergraduate students’ refractive error, visual acuity, stereo-acuity, amplitude of accommodation, near point of convergence, associated heterophoria at near, colour vision and ocular motility. Participants chose an overlay or combination of overlays with colour optimal for clarity, and completed the Wilkins Rate of Reading Test with and without an overlay(s) of this colour. Results Overall, there was a significant increase in reading speed with overlay (t(72) = −5.26, p < 0.0005). Twenty-six participants (36%) increased their reading rate by >5% with their chosen coloured overlay(s). Ten participants (14%) had a reading speed increase of >10%. The increase in reading speed was not significantly associated with any clinical finding. Conclusion Tests which are completed in routine eye examinations did not identify those participants who benefitted from coloured overlays in terms of reading speed. PMID:25455572
... is the device most commonly used for external beam radiation treatments for patients with cancer. The linear ... shape of the patient's tumor and the customized beam is directed to the patient's tumor. The beam ...
Isolated linear blaschkoid psoriasis.
Nasimi, M; Abedini, R; Azizpour, A; Nikoo, A
2016-10-01
Linear psoriasis (LPs) is considered a rare clinical presentation of psoriasis, which is characterized by linear erythematous and scaly lesions along the lines of Blaschko. We report the case of a 20-year-old man who presented with asymptomatic linear and S-shaped erythematous, scaly plaques on right side of his trunk. The plaques were arranged along the lines of Blaschko with a sharp demarcation at the midline. Histological examination of a skin biopsy confirmed the diagnosis of psoriasis. Topical calcipotriol and betamethasone dipropionate ointments were prescribed for 2 months. A good clinical improvement was achieved, with reduction in lesion thickness and scaling. In patients with linear erythematous and scaly plaques along the lines of Blaschko, the diagnosis of LPs should be kept in mind, especially in patients with asymptomatic lesions of late onset. PMID:27663156
NASA Technical Reports Server (NTRS)
Laughlin, Darren
1995-01-01
Inertial linear actuators developed to suppress residual accelerations of nominally stationary or steadily moving platforms. Function like long-stroke version of voice coil in conventional loudspeaker, with superimposed linear variable-differential transformer. Basic concept also applicable to suppression of vibrations of terrestrial platforms. For example, laboratory table equipped with such actuators plus suitable vibration sensors and control circuits made to vibrate much less in presence of seismic, vehicular, and other environmental vibrational disturbances.
Shetty, Shricharith; Rao, Raghavendra; Kudva, R Ranjini; Subramanian, Kumudhini
2016-01-01
Alopecia areata (AA) over scalp is known to present in various shapes and extents of hair loss. Typically it presents as circumscribed patches of alopecia with underlying skin remaining normal. We describe a rare variant of AA presenting in linear band-like form. Only four cases of linear alopecia have been reported in medical literature till today, all four being diagnosed as lupus erythematosus profundus. PMID:27625568
Shetty, Shricharith; Rao, Raghavendra; Kudva, R Ranjini; Subramanian, Kumudhini
2016-01-01
Alopecia areata (AA) over scalp is known to present in various shapes and extents of hair loss. Typically it presents as circumscribed patches of alopecia with underlying skin remaining normal. We describe a rare variant of AA presenting in linear band-like form. Only four cases of linear alopecia have been reported in medical literature till today, all four being diagnosed as lupus erythematosus profundus.
Shetty, Shricharith; Rao, Raghavendra; Kudva, R Ranjini; Subramanian, Kumudhini
2016-01-01
Alopecia areata (AA) over scalp is known to present in various shapes and extents of hair loss. Typically it presents as circumscribed patches of alopecia with underlying skin remaining normal. We describe a rare variant of AA presenting in linear band-like form. Only four cases of linear alopecia have been reported in medical literature till today, all four being diagnosed as lupus erythematosus profundus. PMID:27625568
Routine detection of Clostridium difficile in Western Australia.
Collins, Deirdre A; Riley, Thomas V
2016-02-01
Despite increasing infection rates, Clostridium difficile is not currently routinely tested for in all diarrhoeal faecal specimens in Australia. In July 2014, all diarrhoeal specimens submitted to a diagnostic laboratory in Western Australia were surveyed to determine the true prevalence of C. difficile. In total, 1010 diarrhoeal non-duplicate faecal specimens were received during the month. Testing for C. difficile was requested, or the criteria for a C. difficile investigation were met, for 678 specimens which were investigated by PCR for the tcdB gene using the BD MAX platform, followed by toxigenic culture on PCR-positive samples. The remaining 332 specimens, with either no C. difficile test request or the criteria for a C. difficile investigation were not met, were examined by toxigenic culture. All isolates were PCR ribotyped. C. difficile was the most commonly detected diarrhoeal pathogen among all specimens. The overall prevalence of C. difficile in all 1010 specimens was 6.4%; 7.2% in the routinely tested group, and 4.8% in the non-requested group. The proportion of non-requested positive detections among all cases was 24.6%. Community-onset infection was present in 50.8% of all cases. The median age of all CDI cases was 60.0 years and the age range in CDI patients in the routine group was 0.6-96.6 years (median 72.7 years), compared to 0.2-2.3 years (median 0.8 years) in the non-requested group. The most common ribotype (RT) found was RT 014/020 (34.1% in the routine group, 43.8% in the non-requested group), followed by RTs 002, 056, 005 and 018. While the routine testing group and the non-requested group differed markedly in age and patient classification, C. difficile was the most common cause of diarrhoea in hospitals and the community in Western Australia. The significance of finding C. difficile in the community paediatric population requires further study.
The routine use of sublingual GTN with resting 99Tcm-tetrofosmin myocardial perfusion imaging.
Thorley, P J; Sheard, K L; Wright, D J; Sivananthan, U M
1998-10-01
Nitrates can be used to improve resting myocardial blood flow in patients with severe coronary artery disease. This may enhance tracer uptake during rest myocardial perfusion imaging. Recent studies using nitrates at rest have shown increased detection of reversible ischaemia in this patient group with the 201Tl and 99Tcm perfusion tracers MIBI and tetrofosmin. However, it is not always possible to assess the severity of coronary artery disease before the rest injection and therefore whether a patient would benefit from nitrate administration. To improve the sensitivity for the detection of reversible ischaemia and to avoid a repeat study with nitrates (especially in patients with 'fixed' defects), a protocol in which all patients routinely receive nitrates prior to the rest injection is required. This prospective study evaluated the effect of nitrate administration prior to rest imaging in a randomly selected group of patients. Thirty patients selected at random from routine referrals had stress, rest and rest + GTN tetrofosmin imaging on three separate days. Changes in reversibility between the rest and rest + GTN images were assessed both visually and using semi-quantitative analysis. Defects at stress were seen in 43 coronary artery territories, 33 of which were reversible at rest and 37 reversible at rest + GTN. Of these 43 defects, 82% demonstrated either increased or the same degree of reversibility at rest + GTN imaging compared to standard rest imaging. All defects with reduced reversibility at rest + GTN imaging (i.e. the remaining 18%) were, however, still reversible compared to the stress images. Some of this reduced reversibility may be due to attenuation artefacts. We conclude that the routine use of GTN with rest tetrofosmin imaging will result in increased detection of ischaemic areas with no loss of sensitivity or specificity.
Routine analysis of ultra pure water by ICP-MS in the low- and sub-ng/L level.
Hoelzl, R; Fabry, L; Kotz, L; Pahlke, S
2000-01-01
The chemical analysis with inductively coupled plasma-mass spectrometry (ICP-MS) can help to examine the purity of ultra pure water (UPW) down to 10 part per trillion (ng/L) and lower. For a proper determination of a high number of samples per week the analysis must be divided into two parts: the routine analysis and the reference water analysis. The routine analysis is done by direct measurement of the ultra pure water samples. Applying a standard addition method under particular clean conditions, the reference water analysis leads to the definition of the accurate zero. A quick evaluation scheme is also presented for the reference water analysis. The method is tested for its fitness for application by examining LOD (for relevant element < 2 ng/L), reproducibility and linearity of calibration. The ICP-MS was optimized according to the methodology of G. Taguchi to improve reproducibility and LOD. PMID:11225818
Clinical Question: Does Medical Evidence Support Routine Oronasopharyngeal Suction at Delivery?
Evans, M Blake; Po, William D
2016-01-01
Oronasopharyngeal suction (ONPS) is regularly performed in neonates at delivery in many hospitals across the country today. Although ONPS is a technique that has essentially become habitual for most obstetricians, its theorized usefulness to help promote expeditious lung aeration after delivery by removal of amniotic fluid, meconium, mucus and blood that may otherwise be aspirated by the newborn, is currently not recommended. ONPS can cause vagal stimulation-induced bradycardia and thus hypercapnea, iatrogenic infection due to mucous membrane injury, and development of subsequent neonatal brain injury due to changes in cerebral blood flow regulation, particularly in premature infants. Multiple studies that have been performed comparing routine use of ONPS to no intervention controls indicate that newborns receiving ONPS took a longer time to achieve normal oxygen saturations, caused apneic episodes, and caused disturbances in heart rate (mainly bradycardia) compared to the control groups. Although the ONPS groups revealed no significantly different APGAR scores at 1 and 5 minutes, the ONPS groups took longer than the control group to reach an arterial oxygen saturation greater than or equal to 92% in the first minutes of life. Currently, Neonatal Resuscitation Program guidelines discourage the use of or meconium-stained amniotic fluid and in the absence of obvious obstruction. Furthermore, this manuscript highlights various literature sources revealing that the routine use of ONPS at the time of delivery can cause more harm than good, if any good at all.
Clinical Question: Does Medical Evidence Support Routine Oronasopharyngeal Suction at Delivery?
Evans, M Blake; Po, William D
2016-01-01
Oronasopharyngeal suction (ONPS) is regularly performed in neonates at delivery in many hospitals across the country today. Although ONPS is a technique that has essentially become habitual for most obstetricians, its theorized usefulness to help promote expeditious lung aeration after delivery by removal of amniotic fluid, meconium, mucus and blood that may otherwise be aspirated by the newborn, is currently not recommended. ONPS can cause vagal stimulation-induced bradycardia and thus hypercapnea, iatrogenic infection due to mucous membrane injury, and development of subsequent neonatal brain injury due to changes in cerebral blood flow regulation, particularly in premature infants. Multiple studies that have been performed comparing routine use of ONPS to no intervention controls indicate that newborns receiving ONPS took a longer time to achieve normal oxygen saturations, caused apneic episodes, and caused disturbances in heart rate (mainly bradycardia) compared to the control groups. Although the ONPS groups revealed no significantly different APGAR scores at 1 and 5 minutes, the ONPS groups took longer than the control group to reach an arterial oxygen saturation greater than or equal to 92% in the first minutes of life. Currently, Neonatal Resuscitation Program guidelines discourage the use of or meconium-stained amniotic fluid and in the absence of obvious obstruction. Furthermore, this manuscript highlights various literature sources revealing that the routine use of ONPS at the time of delivery can cause more harm than good, if any good at all. PMID:27328554
The linearized characteristics method and its application to practical nonlinear supersonic problems
NASA Technical Reports Server (NTRS)
Ferri, Antonio
1952-01-01
The methods of characteristics has been linearized by assuming that the flow field can be represented as a basic flow field determined by nonlinearized methods and a linearized superposed flow field that accounts for small changes of boundary conditions. The method has been applied to two-dimensional rotational flow where the basic flow is potential flow and to axially symmetric problems where conical flows have been used as the basic flows. In both cases the method allows the determination of the flow field to be simplified and the numerical work to be reduced to a few calculations. The calculations of axially symmetric flow can be simplified if tabulated values of some coefficients of the conical flow are obtained. The method has also been applied to slender bodies without symmetry and to some three-dimensional wing problems where two-dimensional flow can be used as the basic flow. Both problems were unsolved before in the approximation of nonlinear flow.
Superconducting linear actuator
NASA Technical Reports Server (NTRS)
Johnson, Bruce; Hockney, Richard
1993-01-01
Special actuators are needed to control the orientation of large structures in space-based precision pointing systems. Electromagnetic actuators that presently exist are too large in size and their bandwidth is too low. Hydraulic fluid actuation also presents problems for many space-based applications. Hydraulic oil can escape in space and contaminate the environment around the spacecraft. A research study was performed that selected an electrically-powered linear actuator that can be used to control the orientation of a large pointed structure. This research surveyed available products, analyzed the capabilities of conventional linear actuators, and designed a first-cut candidate superconducting linear actuator. The study first examined theoretical capabilities of electrical actuators and determined their problems with respect to the application and then determined if any presently available actuators or any modifications to available actuator designs would meet the required performance. The best actuator was then selected based on available design, modified design, or new design for this application. The last task was to proceed with a conceptual design. No commercially-available linear actuator or modification capable of meeting the specifications was found. A conventional moving-coil dc linear actuator would meet the specification, but the back-iron for this actuator would weigh approximately 12,000 lbs. A superconducting field coil, however, eliminates the need for back iron, resulting in an actuator weight of approximately 1000 lbs.
Repair of overheating linear accelerator
Barkley, Walter; Baldwin, William; Bennett, Gloria; Bitteker, Leo; Borden, Michael; Casados, Jeff; Fitzgerald, Daniel; Gorman, Fred; Johnson, Kenneth; Kurennoy, Sergey; Martinez, Alberto; O’Hara, James; Perez, Edward; Roller, Brandon; Rybarcyk, Lawrence; Stark, Peter; Stockton, Jerry
2004-01-01
Los Alamos Neutron Science Center (LANSCE) is a proton accelerator that produces high energy particle beams for experiments. These beams include neutrons and protons for diverse uses including radiography, isotope production, small feature study, lattice vibrations and material science. The Drift Tube Linear Accelerator (DTL) is the first portion of a half mile long linear section of accelerator that raises the beam energy from 750 keV to 100 MeV. In its 31st year of operation (2003), the DTL experienced serious issues. The first problem was the inability to maintain resonant frequency at full power. The second problem was increased occurrences of over-temperature failure of cooling hoses. These shortcomings led to an investigation during the 2003 yearly preventative maintenance shutdown that showed evidence of excessive heating: discolored interior tank walls and coper oxide deposition in the cooling circuits. Since overheating was suspected to be caused by compromised heat transfer, improving that was the focus of the repair effort. Investigations revealed copper oxide flow inhibition and iron oxide scale build up. Acid cleaning was implemented with careful attention to protection of the base metal, selection of components to clean and minimization of exposure times. The effort has been very successful in bringing the accelerator through a complete eight month run cycle allowing an incredible array of scientific experiments to be completed this year (2003-2004). This paper will describe the systems, investigation analysis, repair, return to production and conclusion.
Acute effects of routine firefighting on lung function.
Sheppard, D; Distefano, S; Morse, L; Becker, C
1986-01-01
We undertook a study to determine the acute effects of routine firefighting on lung function and the relationship between these acute effects and nonspecific airway responsiveness. For 29 firefighters from a single fire station, we calculated the concentration of methacholine aerosol that caused a 100% increase in specific airway resistance (Pc100). Over an 8-week period we than measured FEV1 and FVC in each firefighter before and after each 24-hr workshift and after every fire. From 199 individual workshifts without fires, we calculated the mean +/- 2 SD across-workshift change in FEV1 and FVC for each firefighter. Eighteen of 76 measurements obtained within 2 hr after a fire (24%) showed a greater than 2 SD fall in FEV1 and/or FVC compared to two of 199 obtained after routine workshifts without fires (1%; p less than .001). On 13 of 18 occasions when spirometry decreased significantly, we obtained repeat spirometry (postshift) 3-18.5 hr after fires, and on four of these occasions FEV1 and/or FVC were still more than 2 SD below baseline. Decrements in spirometry occurred as often in firefighters with high Pc100s as in those with low Pc100s. In two firefighters in whom FEV1 and FVC fell by more than 10% after fires, we repeated measurements of methacholine sensitivity, and it was increased over the prestudy baseline. These findings suggest that routine firefighting is associated with a high incidence of acute decrements in lung function.(ABSTRACT TRUNCATED AT 250 WORDS)
Polio inactivated vaccine costs into routine childhood immunization in Brazil.
Sartori, Ana Marli Christovam; Vicentine, Margarete Paganotti; Gryninger, Lígia Castelloni Figueiredo; Soárez, Patricia Coelho de; Novaes, Hillegonda Maria Dutilh
2015-01-01
OBJECTIVE To analyze the costs of vaccination regimens for introducing inactivated polio vaccine in routine immunization in Brazil. METHODS A cost analysis was conducted for vaccines in five vaccination regimens, including inactivated polio vaccine, compared with the oral polio vaccine-only regimen. The costs of the vaccines were estimated for routine use and for the "National Immunization Days", during when the oral polio vaccine is administered to children aged less than five years, independent of their vaccine status, and the strategic stock of inactivated polio vaccine. The presented estimated costs are of 2011. RESULTS The annual costs of the oral vaccine-only program (routine and two National Immunization Days) were estimated at US$19,873,170. The incremental costs of inclusion of the inactivated vaccine depended on the number of vaccine doses, presentation of the vaccine (bottles with single dose or ten doses), and number of "National Immunization Days" carried out. The cost of the regimen adopted with two doses of inactivated vaccine followed by three doses of oral vaccine and one "National Immunization Day" was estimated at US$29,653,539. The concomitant replacement of the DTPw/Hib and HepB vaccines with the pentavalent vaccine enabled the introduction of the inactivated polio without increasing the number of injections or number of visits needed to complete the vaccination. CONCLUSIONS The introduction of the inactivated vaccine increased the annual costs of the polio vaccines by 49.2% compared with the oral vaccine-only regimen. This increase represented 1.13% of the expenditure of the National Immunization Program on the purchase of vaccines in 2011.
An individualistic approach to routine cadaver organ removal.
Peters, D A
1988-09-01
Consenting to the taking of one's organs after death is a moral duty--the duty to consent--which derives from a more general moral duty--the duty to attempt an easy rescue of an endangered person. These two duties can be justified within the framework of factual and value beliefs associated with the general intellectual orientation called "individualism," which informs the liberal democratic tradition in the spirit of John Locke. Individualists value personal liberty and would accept these two duties on the ground that personal liberty is likely to be better protected and advanced in a society that abides by them than in a society that does not. The same reasoning justifies a social policy of routine removal of cadaver organs. Individualists would find it prudent to give up their right to be buried whole and adopt a policy of routine removal of cadaver organs, with organs distributed according to some principle of fair allocation. Since they recognize that their own organs will be of no use to them after death, giving up their right to be buried whole will not be viewed as a significant sacrifice of personal liberty. Some people of basic individualistic sympathies may, however, embrace additional special values that favor their being buried whole. To accommodate such persons, two compromises on a policy of routine taking of cadaver organs are possible: Allow these persons to "opt out" of the system by signing a legally binding document prohibiting the taking of their organs after death, or require everyone to state on their driver's licenses a positive or negative decision concerning organ removal.(ABSTRACT TRUNCATED AT 250 WORDS)
Polio inactivated vaccine costs into routine childhood immunization in Brazil
Sartori, Ana Marli Christovam; Vicentine, Margarete Paganotti; Gryninger, Lígia Castelloni Figueiredo; de Soárez, Patricia Coelho; Novaes, Hillegonda Maria Dutilh
2015-01-01
OBJECTIVE To analyze the costs of vaccination regimens for introducing inactivated polio vaccine in routine immunization in Brazil. METHODS A cost analysis was conducted for vaccines in five vaccination regimens, including inactivated polio vaccine, compared with the oral polio vaccine-only regimen. The costs of the vaccines were estimated for routine use and for the “National Immunization Days”, during when the oral polio vaccine is administered to children aged less than five years, independent of their vaccine status, and the strategic stock of inactivated polio vaccine. The presented estimated costs are of 2011. RESULTS The annual costs of the oral vaccine-only program (routine and two National Immunization Days) were estimated at US$19,873,170. The incremental costs of inclusion of the inactivated vaccine depended on the number of vaccine doses, presentation of the vaccine (bottles with single dose or ten doses), and number of “National Immunization Days” carried out. The cost of the regimen adopted with two doses of inactivated vaccine followed by three doses of oral vaccine and one “National Immunization Day” was estimated at US$29,653,539. The concomitant replacement of the DTPw/Hib and HepB vaccines with the pentavalent vaccine enabled the introduction of the inactivated polio without increasing the number of injections or number of visits needed to complete the vaccination. CONCLUSIONS The introduction of the inactivated vaccine increased the annual costs of the polio vaccines by 49.2% compared with the oral vaccine-only regimen. This increase represented 1.13% of the expenditure of the National Immunization Program on the purchase of vaccines in 2011. PMID:25741645
NASA Technical Reports Server (NTRS)
Leviton, Douglas B. (Inventor)
1993-01-01
A Linear Motion Encoding device for measuring the linear motion of a moving object is disclosed in which a light source is mounted on the moving object and a position sensitive detector such as an array photodetector is mounted on a nearby stationary object. The light source emits a light beam directed towards the array photodetector such that a light spot is created on the array. An analog-to-digital converter, connected to the array photodetector is used for reading the position of the spot on the array photodetector. A microprocessor and memory is connected to the analog-to-digital converter to hold and manipulate data provided by the analog-to-digital converter on the position of the spot and to compute the linear displacement of the moving object based upon the data from the analog-to-digital converter.
Semi-automatic method for routine evaluation of fibrinolytic components.
Collen, D; Tytgat, G; Verstraete, M
1968-11-01
A semi-automatic method for the routine evaluation of fibrinolytic activity is described. The principle is based upon graphic recording by a multichannel voltmeter of tension drops over a potentiometer, caused by variations in the influence of light upon a light-dependent resistance, resulting from modifications in the composition of the fibrin fibres by lysis. The method is applied to the assessment of certain fibrinolytic factors with widespread fibrinolytic endpoints, and the results are compared with simultaneously obtained visual data on the plasmin assay, the plasminogen assay, and on the euglobulin clot lysis time.
THERMAL: A routine designed to calculate neutron thermal scattering
Cullen, D.E.
1995-02-24
THERMAL is designed to calculate neutron thermal scattering that is isotropic in the center of mass system. At low energy thermal motion will be included. At high energies the target nuclei are assumed to be stationary. The point of transition between low and high energies has been defined to insure a smooth transition. It is assumed that at low energy the elastic cross section is constant in the center of mass system. At high energy the cross section can be of any form. You can use this routine for all energies where the elastic scattering is isotropic in the center of mass system. In most materials this will be a fairly high energy.