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.
Collection of parallel linear equations routines for the Denelcor HEP
Dongarra, J.J.; Hiromoto, R.E.
1983-09-01
This note describes the implementation and performance results for a few standard linear algebra routines on the Denelcor HEP computer. The algorithms used here are based on high-level modules which facilitate portability and perform efficiently in a wide range of environments.
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
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.
NASA Technical Reports Server (NTRS)
Cunningham, A. M., Jr.
1976-01-01
The feasibility of calculating steady mean flow solutions for nonlinear transonic flow over finite wings with a linear theory aerodynamic computer program is studied. The methodology is based on independent solutions for upper and lower surface pressures that are coupled through the external flow fields. Two approaches for coupling the solutions are investigated which include the diaphragm and the edge singularity method. The final method is a combination of both where a line source along the wing leading edge is used to account for blunt nose airfoil effects; and the upper and lower surface flow fields are coupled through a diaphragm in the plane of the wing. An iterative solution is used to arrive at the nonuniform flow solution for both nonlifting and lifting cases. Final results for a swept tapered wing in subcritical flow show that the method converges in three iterations and gives excellent agreement with experiment at alpha = 0 deg and 2 deg. Recommendations are made for development of a procedure for routine application.
SINDA/SINFLO computer routine, volume 1, revision A. [for fluid flow system analysis
NASA Technical Reports Server (NTRS)
Oren, J. A.; Williams, D. R.
1975-01-01
The SINFLO package was developed to modify the SINDA preprocessor to accept and store the input data for fluid flow systems analysis and adding the FLOSOL user subroutine to perform the flow solution. This reduced and simplified the user input required for analysis of flow problems. A temperature calculation method, the flow-hybrid method which was developed in previous VSD thermal simulator routines, was incorporated for calculating fluid temperatures. The calculation method accuracy was improved by using fluid enthalpy rather than specific heat for the convective term of the fluid temperature equation. Subroutines and data input requirements are described along with user subroutines, flow data storage, and usage of the plot program.
A linearized Euler analysis of unsteady transonic flows in turbomachinery
Hall, K.C.; Clark, W.S.; Lorence, C.B. . Dept. of Mechanical Engineering and Materials Science)
1994-07-01
A computational method for efficiently predicting unsteady transonic flows in two- and three-dimensional cascades is presented. The unsteady flow is modeled using a linearized Euler analysis whereby the unsteady flow field is decomposed into a nonlinear mean flow plus a linear harmonically varying unsteady flow. The equations that govern the perturbation flow, the linearized Euler equations, are linear variable coefficient equations. For transonic flows containing shocks, shock capturing is used to model the shock impulse (the unsteady load due to the harmonic motion of the shock). A conservative Lax-Wendroff scheme is used to obtain a set of linearized finite volume equations that describe the harmonic small disturbance behavior of the flow. Conditions under which such a discretization will correctly predict the shock impulse are investigated. Computational results are presented that demonstrate the accuracy and efficiency of the present method as well as the essential role of unsteady shock impulse loads on the flutter stability of fans.
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.
Capsule deformation and orientation in general linear flows
NASA Astrophysics Data System (ADS)
Szatmary, Alex; Eggleton, Charles
2010-11-01
We considered the response of spherical and non-spherical capsules to general flows. (A capsule is an elastic membrane enclosing a fluid, immersed in fluid.) First, we established that nonspherical capsules align with the imposed irrotational linear flow; this means that initial orientation does not affect steady-state capsule deformation, so this steady-state deformation can be determined entirely by the capillary number and the type of flow. The type of flow is characterized by r: r=0 for axisymmetric flows, and r=1 for planar flows; intermediate values of r are combinations of planar and axisymmetric flow. By varying the capillary number and r, all irrotational linear Stokes flows can be generated. For the same capillary number, planar flows lead to more deformation than uniaxial or biaxial extensional flows. Deformation varies monotonically with r, so one can determine bounds on capsule deformation in general flow by only looking at uniaxial, biaxial, and planar flow. These results are applicable to spheres in all linear flows and to ellipsoids in irrotational linear flow.
Will 3-dimensional PET-CT enable the routine quantification of myocardial blood flow?
deKemp, Robert A; Yoshinaga, Keiichiro; Beanlands, Rob S B
2007-01-01
Quantification of myocardial blood flow (MBF) and flow reserve has been used extensively with positron emission tomography (PET) to investigate the functional significance of coronary artery disease. Increasingly, flow quantification is being applied to investigations of microvascular dysfunction in early atherosclerosis and in nonatherosclerotic microvascular disease associated with primary and secondary cardiomyopathies. Fully three-dimensional (3D) acquisition is becoming the standard imaging mode on new equipment, bringing with it certain challenges for cardiac PET, but also the potential for MBF to be measured simultaneously with routine electrocardiography (ECG)-gated perfusion imaging. Existing 3D versus 2D comparative studies support the use of 3D cardiac PET for flow quantification, and these protocols can be translated to PET-CT, which offers a virtually noise-free attenuation correction. This technology combines the strengths of cardiac CT for evaluation of anatomy with cardiac PET for quantification of the hemodynamic impact on the myocardium. High throughput clinical imaging protocols are needed to evaluate the incremental diagnostic and prognostic value of this technology. PMID:17556173
A linearized Euler analysis of unsteady flows in turbomachinery
NASA Technical Reports Server (NTRS)
Hall, Kenneth C.; Crawley, Edward F.
1987-01-01
A method for calculating unsteady flows in cascades is presented. The model, which is based on the linearized unsteady Euler equations, accounts for blade loading shock motion, wake motion, and blade geometry. The mean flow through the cascade is determined by solving the full nonlinear Euler equations. Assuming the unsteadiness in the flow is small, then the Euler equations are linearized about the mean flow to obtain a set of linear variable coefficient equations which describe the small amplitude, harmonic motion of the flow. These equations are discretized on a computational grid via a finite volume operator and solved directly subject to an appropriate set of linearized boundary conditions. The steady flow, which is calculated prior to the unsteady flow, is found via a Newton iteration procedure. An important feature of the analysis is the use of shock fitting to model steady and unsteady shocks. Use of the Euler equations with the unsteady Rankine-Hugoniot shock jump conditions correctly models the generation of steady and unsteady entropy and vorticity at shocks. In particular, the low frequency shock displacement is correctly predicted. Results of this method are presented for a variety of test cases. Predicted unsteady transonic flows in channels are compared to full nonlinear Euler solutions obtained using time-accurate, time-marching methods. The agreement between the two methods is excellent for small to moderate levels of flow unsteadiness. The method is also used to predict unsteady flows in cascades due to blade motion (flutter problem) and incoming disturbances (gust response problem).
A linearized Euler analysis of unsteady flows in turbomachinery
NASA Astrophysics Data System (ADS)
Hall, Kenneth C.; Crawley, Edward F.
1987-06-01
A method for calculating unsteady flows in cascades is presented. The model, which is based on the linearized unsteady Euler equations, accounts for blade loading shock motion, wake motion, and blade geometry. The mean flow through the cascade is determined by solving the full nonlinear Euler equations. Assuming the unsteadiness in the flow is small, then the Euler equations are linearized about the mean flow to obtain a set of linear variable coefficient equations which describe the small amplitude, harmonic motion of the flow. These equations are discretized on a computational grid via a finite volume operator and solved directly subject to an appropriate set of linearized boundary conditions. The steady flow, which is calculated prior to the unsteady flow, is found via a Newton iteration procedure. An important feature of the analysis is the use of shock fitting to model steady and unsteady shocks. Use of the Euler equations with the unsteady Rankine-Hugoniot shock jump conditions correctly models the generation of steady and unsteady entropy and vorticity at shocks. In particular, the low frequency shock displacement is correctly predicted. Results of this method are presented for a variety of test cases. Predicted unsteady transonic flows in channels are compared to full nonlinear Euler solutions obtained using time-accurate, time-marching methods. The agreement between the two methods is excellent for small to moderate levels of flow unsteadiness. The method is also used to predict unsteady flows in cascades due to blade motion (flutter problem) and incoming disturbances (gust response problem).
Seeger, Achim; Kramer, Ulrich; Fenchel, Michael; Grimm, Florian; Bretschneider, Christiane; Döring, Jörg; Klumpp, Bernhard; Tepe, Gunnar; Rittig, Kilian; Seidensticker, Peter R; Claussen, Claus D; Miller, Stephan
2008-01-01
Background Previous experiences of whole body MR angiography are predominantly available in linear 0.5 M gadolinium-containing contrast agents. The aim of this study was to compare image quality on a four-point scale (range 1–4) and diagnostic accuracy of a 1.0 M macrocyclic contrast agent (gadobutrol, n = 80 patients) with a 0.5 M linear contrast agent (gadopentetate dimeglumine, n = 85 patients) on a 1.5 T whole body MR system. Digital subtraction angiography served as standard of reference. Results All examinations yielded diagnostic image quality. There was no significant difference in image quality (3.76 ± 0.3 versus 3.78 ± 0.3, p = n.s.) and diagnostic accuracy observed. Sensitivity and specificity of the detection of hemodynamically relevant stenoses was 93%/95% in the gadopentetate dimeglumine group and 94%/94% in the gadobutrol group, respectively. Conclusion The high diagnostic accuracy of gadobutrol in the clinical routine setting is of high interest as medical authorities (e.g. the European Agency for the Evaluation of Medicinal Products) recommend macrocyclic contrast agents especially to be used in patients with renal failure or dialysis. PMID:19116027
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
Instrument Induced Linear Flow Resistance In Öresund
NASA Astrophysics Data System (ADS)
Green, M.; Stigebrandt, A.
Previous studies of the flow resistance in Öresund indicate the presence of a linear rela- tionship between sea-level and flow rate. The linear term is superposed on the common quadratic relationship from bottom friction and form drag. In previous works, cross- stream geostrophy or generation of internal waves have explained the linear term. The present analysis is based on two different flow-rate data sets. The first set was the same data set used in earlier studies showing the linear term. It consists of data from RCM7 and S4. The second set was taken with ADCP. The observations were fitted to two different strait flow models. The first model had a quadratic flow resistance term only, whereas the second had both a quadratic and a linear term. In addition to the current data, sea-level observations from both ends of the strait were used. The analyses showed that the linear term is significant in the first data set but not in the second. This result holds regardless of season and part of data set and current meter and sea-level gauge combination. The only explanation is that it is an artefact caused by non-linear current meter response by the RCM7 and S4 instruments. These meters underestimate the velocity if it is higher than approximately 50 cm/s, which often is the case in Öresund. Published papers support this statement. The linear term is thus an artefact generated by the instruments, and unfortunately not a feature of the physics of the strait flow.
Reardon, D M; Hutchinson, D; Preston, F E; Trowbridge, E A
1985-01-01
The effect of dipotassium ethylenediaminetetraaceticacid (EDTA) on the platelet count and mean volume (MPV) was evaluated using two routine measurement systems, a Coulter S Plus Phase 1 (S+) and a Technicon H6000 (H6000). In normal subjects (n = 29) MPV increased by 17% during 39 h storage in EDTA when measured by the S+. In contrast MPV decreased by 22% when measured by the H6000. MPV differences of up to 40% were observed between the two systems. Concomitant platelet counts, in both systems, changed by less than 4%. Using the anticoagulant sodium citrate and prostaglandin E1 (Na-citrate/PGE1 there were no significant changes in MPV measured by the S+ during 7 h storage, although a linear decrease in platelet count was observed. A decrease in H6000 MPV was observed whether the blood was stored in EDTA or Na-citrate/PGE1. Methodology, anticoagulation and storage time all influence MPV. Until these determinants are standardized the clinical value of MPV cannot be assessed. PMID:3935360
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.
Eidenschink Brodersen, Lisa; Menssen, Andrew J; Wangen, Jamie R; Stephenson, Christine F; de Baca, Monica E; Zehentner, Barbara K; Wells, Denise A; Loken, Michael R
2014-10-21
Introduction: While multidimensional flow cytometry (MDF) has great utility in diagnostic work-ups of patients with suspected myelodysplastic syndromes (MDS), only the myeloid lineage has demonstrated reproducible abnormalities from multiple laboratories. With the effects of ammonium chloride (NH4 Cl) lysis on erythroid progenitors previously described, we applied this protocol to a patient cohort with diagnosed MDS to investigate phenotypic abnormalities that indicate erythroid dysplasia. Method: Bone marrow specimens [39 MDS, 9 acute myeloid leukemia (AML), 7 JAK2(V617F) positive myeloproliferative neoplasms (MPN), 5 nutritional deficiencies] were processed by NH4 Cl lysis and Ficoll preparation and evaluated by MDF using a difference from normal algorithm. Results: For the MDS cohort, phenotypic abnormalities on the mature erythroid progenitors were frequent for CD71 and CD36 (36% for each antigen); abnormalities for CD235a (8%) were observed. Among immature erythroid progenitors, abnormal maturation patterns (≤5%) and increased CD105 intensity (9%) were seen. Increased frequency of CD105 bright cells was observed (18%). While antigenic abnormalities correlated between NH4 Cl lysis and Ficoll preparation, the lysis method demonstrated the most consistent quantitative antigen intensities. Mean erythroid phenotypic abnormalities and prognostic cytogenetic subgroups correlated strongly. Morphologic and erythroid phenotypic abnormalities correlated, as did increasing FCSS and number of erythroid abnormalities, albeit without further increase for AML patients. Discussion: These data expand the understanding of erythropoiesis and define immunophenotypic abnormalities that indicate dyserythropoiesis in MDS utilizing a lysis protocol practical for routine implementation in clinical flow cytometric work-up. Preliminary studies also indicate strong correlation between phenotypic erythroid dysplasia and poor prognosis, as classified cytogenetically. © 2014 Clinical
Linearized analysis of Richtmyer-Meshkov flow for elastic materials
NASA Astrophysics Data System (ADS)
Plohr, Jeeyeon N.; Plohr, Bradley J.
2005-08-01
We present a study of Richtmyer Meshkov flow for elastic materials. This flow, in which a material interface is struck by a shock wave, was originally investigated for gases, where growth of perturbations of the interface is observed. Here we consider two elastic materials in frictionless contact. The governing system of equations comprises conservation laws supplemented by constitutive equations. To analyse it, we linearize the equations around a one-dimensional background solution under the assumption that the perturbation is small. The background problem defines a Riemann problem that is solved numerically; its solution contains transmitted and reflected shock waves in the longitudinal modes. The linearized Rankine Hugoniot condition provides the interface conditions at the longitudinal and shear waves; the frictionless material interface conditions are also linearized. The resulting equations, a linear system of partial differential equations, is solved numerically using a finite-difference method supplemented by front tracking. In verifying the numerical code, we reproduce growth of the interface in the gas case. For the elastic case, in contrast, we find that the material interface remains bounded: the non-zero shear stiffness stabilizes the flow. In particular, the linear theory remains valid at late time. Moreover, we identify the principal mechanism for the stability of Richtmyer Meshkov flow for elastic materials: the vorticity deposited on the material interface during shock passage is propagated away by the shear waves, whereas for gas dynamics it stays on the interface.
Transient growth in linearly stable Taylor-Couette flows
NASA Astrophysics Data System (ADS)
Maretzke, Simon; Hof, Björn; Avila, Marc
2014-03-01
Non-normal transient growth of disturbances is considered as an essential prerequisite for subcritical transition in shear flows, i.e. transition to turbulence despite linear stability of the laminar flow. In this work we present numerical and analytical computations of linear transient growth covering all linearly stable regimes of Taylor--Couette flow. Our numerical experiments reveal comparable energy amplifications in the different regimes. For high shear Reynolds numbers Re the optimal transient energy growth always follows a 2/3-scaling with Re, which allows for large amplifications even in regimes where the presence of turbulence remains debated. In co-rotating Rayleigh-stable flows the optimal perturbations become increasingly columnar in their structure, as the optimal axial wavenumber goes to zero. In this limit of axially invariant perturbations we show that linear stability and transient growth are independent of the cylinders' rotation-ratio and we derive a universal 2/3-scaling of optimal energy growth with Re using WKB-theory. Based on this, a semi-empirical formula for the estimation of linear transient growth valid in all regimes is obtained.
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 and Non-Linear Harmonic Methods for Unsteady Transonic Flow
NASA Astrophysics Data System (ADS)
Gundevia, Rayomand
This thesis explores linear and non-linear computational methods for solving unsteady flow. The eventual goal is to apply these methods to two-dimensional and three-dimensional flutter predictions. In this study the quasi-one-dimensional nozzle is used as a framework for understanding these methods and their limitations. Subsonic and transonic cases are explored as the back-pressure is forced to oscillate with known amplitude and frequency. A steady harmonic approach is used to solve this unsteady problem for which perturbations are said to be small in comparison to the mean flow. The use of a linearized Euler equations (LEE) scheme is good at capturing the flow characteristics but is limited by accuracy to relatively small amplitude perturbations. The introduction of time-averaged second-order terms in the Non-Linear Harmonic (NLH) method means that a better approximation of the mean-valued solution, upon which the linearization is based, can be made. The nonlinear time-accurate Euler solutions are used for comparison and to establish the regimes of unsteadiness for which these schemes fails. The usefulness of the LEE and NLH methods lie in the gains in computational efficiency over the full equations.
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.
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 inclined two-layer stratified flows
NASA Astrophysics Data System (ADS)
Negretti, M. Eletta; Socolofsky, Scott A.; Jirka, Gerhard H.
2008-09-01
Two-layer stratified flows are commonly observed in geophysical and environmental contexts. At the interface between the two layers, both velocity shear and buoyancy interplay, resulting in various modes of instability. Results from a temporal linear stability analysis of a two-layer stratified exchange flow under the action of a mean advection are presented, investigating the effect of a mild bottom slope on the stability of the interface. The spatial acceleration is directly included in the governing stability equations. The results demonstrate that increasing the bottom slope has a similar effect on the stability of the flow as does increasing the ratio R of the thickness of the velocity mixing layer δν to that of the density layer δρ as it causes the flow to be more unstable to the Kelvin-Helmholtz instabilities. The transition from Kelvin-Helmholtz modes to stable flow occurs at lower Richardson numbers and wavenumbers compared to the horizontal two-layer flow. Kelvin-Helmholtz modes are decreasingly amplified for 1
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.
Linearized pipe flow to Reynolds number 10 7
NASA Astrophysics Data System (ADS)
Meseguer, Á.; Trefethen, L. N.
2003-03-01
A Fourier-Chebyshev Petrov-Galerkin spectral method is described for high-accuracy computation of linearized dynamics for flow in an infinite circular pipe. Our code is unusual in being based on solenoidal velocity variables and in being written in MATLAB. Systematic studies are presented of the dependence of eigenvalues, transient growth factors, and other quantities on the axial and azimuthal wave numbers and the Reynolds number R for R ranging from 10 2 to the idealized (physically unrealizable) value 10 7. Implications for transition to turbulence are considered in the light of recent theoretical results of S.J. Chapman.
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.
Asymptotic behavior of linearized pipe flow and implications for transition
NASA Astrophysics Data System (ADS)
Meseguer, Alvaro; Trefethen, Lloyd N.
2000-11-01
A solenoidal Petrov-Galerkin MATLAB spectral code is described for high-accuracy computation of linearized dynamics for Hagen-Poiseuille flow in an infinite circular pipe. Systematic studies are presented of the dependence of eigenvalues, transient growth factors, and other quantities on the discretization parameters, the axial and azimuthal wave numbers, and the Reynolds number Re for Re ranging from 10^2 to the idealized (physically unrealizable) value 10^7. Implications for transition to turbulence are considered in the light of the recent theoretical results of S. J. Chapman. Our computations are in agreement with Chapman's predicted threshold amplitude for transition of order Re-3/2 as Re --> ∞.
Nonaxisymmetric linear instability of cylindrical magnetohydrodynamic Taylor-Couette flow
NASA Astrophysics Data System (ADS)
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), 10.1017/jfm.2014.614] and its validity in the linear regime.
Allou, Kaoutar; Vial, Jean-Philippe; Béné, Marie C; Lacombe, Francis
2015-01-01
The complete blood cell count and white blood cell differential are the first step in the biological diagnosis of hematological diseases. Both are currently performed by automated instruments which control data and produce alerts. If such flags are activated, the automated differential cannot be validated and the operator must activate a visual blood smear review. Microscopic examination is still today the reference method despite its lack of sensitivity and reproducibility. The HematoFlow™ (Beckman Coulter) system is the first flow cytometry commercialized method designed for the routine differential. Using six markers in five colors and an automated gating strategy, it provides differentials proven to be reliable for 17 leukocyte subpopulations detection. Relying first on a retrospective analysis of 6,462 blood samples processed by HematoFlow™, thresholds were determined to detect the presence of immature granulocytes and/or blast cells. All possible gating strategy misclassifications of leukocyte subpopulations were then summarized in a systematic nomenclature leading to the development of an original flag system based on the detection of aberrant localization of cell events in specific new bivariate histograms. Ultimately, more than 50% of the results could be automatically validated using the HematoFlow™ system, without any false negative, thereby dramatically contributing to an important decrease of technicians' workload. Moreover a noticeable help was given for smear review interpretation and new immunological flags led to the confirmation of blood disease after classical immunophenotyping. These results were confirmed in a second prospective study including 15,335 cases, where more than 50% of the results were automatically validated by this new flag system. MFC stands as being more and more essential for analyzing differentials in routine and this new flag system could greatly improve its implementation. PMID:25906976
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
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.
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
Understanding heat and fluid flow in linear GTA welds
Zacharia, T.; David, S.A.; Vitek, J.M.
1992-12-31
A transient heat flow and fluid flow model was used to predict the development of gas tungsten arc (GTA) weld pools in 1.5 mm thick AISI 304 SS. The welding parameters were chosen so as to correspond to an earlier experimental study which produced high-resolution surface temperature maps. The motivation of the present study was to verify the predictive capability of the computational model. Comparison of the numerical predictions and experimental observations indicate good agreement.
Understanding heat and fluid flow in linear GTA welds
Zacharia, T.; David, S.A.; Vitek, J.M.
1992-01-01
A transient heat flow and fluid flow model was used to predict the development of gas tungsten arc (GTA) weld pools in 1.5 mm thick AISI 304 SS. The welding parameters were chosen so as to correspond to an earlier experimental study which produced high-resolution surface temperature maps. The motivation of the present study was to verify the predictive capability of the computational model. Comparison of the numerical predictions and experimental observations indicate good agreement.
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.
Linear coupling of acoustic and cyclotron waves in plasma flows
NASA Astrophysics Data System (ADS)
Rogava, Andria; Gogoberidze, Grigol
2005-05-01
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.
Non linear volume flow dependence on osmotic pressure difference in frog skin.
Celentano, F; Monticelli, G; Orsenigo, M N
1978-01-01
The volume flow dependence upon the osmotic pressure difference of both impermeant (sucrose) and permeable (NaCl) species has been investigated in leg skin bags of Rana esculenta. It is concluded: 1. The hydration-dehydration error in the flow measurement with leg skin bags is negligible. 2. The flow-force relationship is non-linear. 3. Unstirred layers and solute permeation have little, if any, influence on non linearity. 4. Structural modifications of the skin induced with hypertonic solutions have been observed and may contribute to non linearity, as well as the multiple-barrier effect. PMID:310878
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.
Calculation of unsteady flows in turbomachinery using the linearized Euler equations
NASA Astrophysics Data System (ADS)
Hall, Kenneth C.; Crawley, Edward F.
1989-06-01
A method for calculating unsteady flows in cascades is presented. The model, which is based on the linearized unsteady Euler equations, accounts for blade loading shock motion, wake motion, and blade geometry. The mean flow through the cascade is determined by solving the full nonlinear Euler equations. Assuming the unsteadiness in the flow is small, then the Euler equations are linearized about the mean flow to obtain a set of linear variable coefficient equations which describe the small amplitude, harmonic motion of the flow. These equations are discretized on a computational grid via a finite volume operator and solved directly subject to an appropriate set of linearized boundary conditions. The steady flow, which is calculated prior to the unsteady flow, is found via a Newton iteration procedure. An important feature of the analysis is the use of shock fitting to model steady and unsteady shocks. Use of the Euler equations with the unsteady Rankine-Hugoniot shock jump conditions correctly models the generation of steady and unsteady entropy and vorticity at shocks. In particular, the low frequency shock displacement is correctly predicted. Results of this method are presented for a variety of test cases. Predicted unsteady transonic flows in channels are compared to full nonlinear Euler solutions obtained using time-accurate, time-marching methods. The agreement between the two methods is excellent for small to moderate levels of flow unsteadiness. The method is also used to predict unsteady flows in cascades due to blade motion (flutter problem) and incoming disturbances (gust response problem).
Effect of depth order on linear vection with optical flows.
Seya, Yasuhiro; Tsuji, Takayuki; Shinoda, Hiroyuki
2014-01-01
In the present study, the effects of depth order on forward and backward vection were examined using optical flows simulating motion in depth (i.e., approaching or receding). In an experiment, space extending 10 or 20 m in depth was simulated, and the space was divided into foreground and background spaces. In each space, a random-dot pattern was presented and the binocular disparity, size, and velocity of each dot were continuously manipulated in a way consistent with the depth being simulated. Participants reported whether they perceived vection. Latency, total duration (i.e., the amount of time that participants reported perceiving vection during a 60-s presentation), and strong-vection duration (i.e., the amount of time that participants reported perceiving strong vection) were measured. The results indicated that, even though the dots making up the optical flow were much smaller and slower moving in the background space than in the foreground space, vection was strongly dependent on flow motion in the background space. This supports the idea that the perceptual system uses background stimulus motion as a reliable cue for self-motion perception. PMID:25926971
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.
Stochastic Estimation and Non-Linear Wall-Pressure Sources in a Separating/Reattaching Flow
NASA Technical Reports Server (NTRS)
Naguib, A.; Hudy, L.; Humphreys, W. M., Jr.
2002-01-01
Simultaneous wall-pressure and PIV measurements are used to study the conditional flow field associated with surface-pressure generation in a separating/reattaching flow established over a fence-with-splitter-plate geometry. The conditional flow field is captured using linear and quadratic stochastic estimation based on the occurrence of positive and negative pressure events in the vicinity of the mean reattachment location. The results shed light on the dominant flow structures associated with significant wall-pressure generation. Furthermore, analysis based on the individual terms in the stochastic estimation expansion shows that both the linear and non-linear flow sources of the coherent (conditional) velocity field are equally important contributors to the generation of the conditional surface pressure.
Analytical Solution to the MHD Flow of Micropolar Fluid Over a Linear Stretching Sheet
NASA Astrophysics Data System (ADS)
Siddheshwar, P. G.; Mahabaleshwar, U. S.
2015-05-01
The flow due to a linear stretching sheet in a fluid with suspended particles, modeled as a micropolar fluid, is considered. All reported works on the problem use numerical methods of solution or a regular perturbation technique. An analytical solution is presented in the paper for the coupled non-linear differential equations with inhomogeneous boundary conditions.
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.
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.
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.
Linear Instability of a Uni-Directional Transversely Sheared Mean Flow
NASA Technical Reports Server (NTRS)
Wundrow, David W.
1996-01-01
The effect of spanwise-periodic mean-flow distortions (i.e. streamwise-vortex structures) on the evolution of small-amplitude, single-frequency instability waves in an otherwise two-dimensional shear flow is investigated. The streamwise-vortex structures are taken to be just weak enough so that the spatially growing instability waves behave (locally) like linear perturbations about a uni-directional transversely sheared mean flow. Numerical solutions are computed and discussed for both the mean flow and the instability waves. The influence of the streamwise-vortex wavelength on the properties of the most rapidly growing instability wave is also discussed.
NASA Astrophysics Data System (ADS)
AMABILI, M.; PELLICANO, F.; PAÏDOUSSIS, M. P.
1999-08-01
The study presented is an investigation of the non-linear dynamics and stability of simply supported, circular cylindrical shells containing inviscid incompressible fluid flow. Non-linearities due to large-amplitude shell motion are considered by using the non-linear Donnell's shallow shell theory, with account taken of the effect of viscous structural damping. Linear potential flow theory is applied to describe the fluid-structure interaction. The system is discretiszd by Galerkin's method, and is investigated by using a model involving seven degrees of freedom, allowing for travelling wave response of the shell and shell axisymmetric contraction. Two different boundary conditions are applied to the fluid flow beyond the shell, corresponding to: (i) infinite baffles (rigid extensions of the shell), and (ii) connection with a flexible wall of infinite extent in the longitudinal direction, permitting solution by separation of variables; they give two different kinds of dynamical behaviour of the system, as a consequence of the fact that axisymmetric contraction, responsible for the softening non-linear dynamical behaviour of shells, is not allowed if the fluid flow beyond the shell is constrained by rigid baffles. Results show that the system loses stability by divergence.
Subcritical transition in plane Poiseuille flow as a linear instability process
NASA Astrophysics Data System (ADS)
Roizner, Federico; Karp, Michael; Cohen, Jacob
2016-05-01
In this work, a transition scenario is demonstrated, in which most of the stages are followed analytically. The transition is initiated by the linear transient growth mechanism in plane Poiseuille flow subjected to an infinitesimally small secondary disturbance. A novel analytical approximation of the linear transient growth mechanism enables us to perform a secondary linear stability analysis of the modified base-flow. Two possible routes to transition are highlighted here, both correspond to a small secondary disturbance superimposed on a linear transient growth. The first scenario is initiated by four decaying odd normal modes which form a counter-rotating vortex pair; the second is initiated by five even decaying modes which form a pair of counter-rotating pairs. The approximation of the linear transient growth stage by a combination of minimal number of modes allows us to follow the transition stages analytically by employing the multiple time scale method. In particular, the secondary instability stage is followed analytically using linear tools, and is verified by obtaining transition in a direct numerical simulation initiated by conditions dictated by the transient growth analytical expressions. Very good agreement is observed, verifying the theoretical model. The similarities between the two transition routes are discussed and the results are compared with similar results obtained for plane Couette flow.
Linear stability of pressure-driven flow over longitudinal superhydrophobic grooves
NASA Astrophysics Data System (ADS)
Yu, K. H.; Teo, C. J.; Khoo, B. C.
2016-02-01
The modal analysis of pressure-driven flows in channels patterned with superhydrophobic surfaces containing periodic grooves and ribs aligned longitudinally to the flow direction has been performed. The effects of shear-free fraction (" separators=" δ ) and groove-rib spatial period normalized by full-channel height (" separators=" L ) on the linear flow stability of such flows have been explored. By performing a BiGlobal linear stability analysis via the pseudo-spectral method, such surfaces have been found to potentially exert a stabilizing or destabilizing effect on the base flow, depending predominantly on the normalized groove-rib spacing. For small values of L (i.e., L = 0.01 and 0.02), a stabilizing effect is predicted for flows over longitudinal superhydrophobic grooves, in agreement with the results obtained using a local stability analysis which employs a homogeneous slip condition along the walls. For a moderate value of normalized groove-rib spacing where the groove-rib periodic spacing is one-tenth of the channel height, the presence of longitudinal superhydrophobic grooves leads to flow instabilities at a lower critical Reynolds number. The redistribution of the base flow resulting from the vanishing shear rates along the liquid-gas interface could give rise to an inflectional instability that promotes temporal instability. The effects of patterning the superhydrophobic surfaces on one or both channel walls are also examined.
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.
Polimeni, P I; Ottenbreit, B; Coleman, P
1985-07-01
The addition of small amounts of high mol. wt polymers to a fluid moving through a pipe typically increases fluid viscosity and thereby diminishes the rate of flow. Under appropriate conditions of flow, however, the addition of linear polymers of high mol. wt--of the order of 10(5) to 10(7) daltons--may cause the flow to increase as much as 3-fold and occasionally more without altering the driving pressure. This effect, generally known to hydrodynamicists under the rubric 'Toms phenomenon' or as 'polymer drag reduction', generally occurs at high (greater than 1000) Reynolds numbers. However, flow also increases at much lower Reynolds numbers under certain conditions, including oscillatory, pulsatile, and helicoidal flows and flow through a column of sand. The Toms phenomenon has been repeatedly observed in various types of flow with both aqueous and organic solvents in combination with a wide variety of polymer additives. A marked fall in the pressure gradients of constant blood flows through pipes has also been observed upon the addition of polyacrylamide, poly(ethylene oxide), deoxyribonucleic acid, or a polysaccharide extracted from okra. It is the consensus among students of fluid mechanics that linear macromolecules suppress flow disturbances by stabilizing or laminizing the dynamic fluid structure when rod- or thread-like particles align themselves parallel to the axis of flow. Mostardi et al. demonstrated with hot film anemometry that aortic flow instabilities downstream from a temporary partial occlusion are dampened after infusion of a polymer drag-reducing agent, Separan AP-30 (Dow Chemical Co.).(ABSTRACT TRUNCATED AT 250 WORDS) PMID:4020886
Malik, M; Dey, J; Alam, Meheboob
2008-03-01
Linear stability and the nonmodal transient energy growth in compressible plane Couette flow are investigated for two prototype mean flows: (a) the uniform shear flow with constant viscosity, and (b) the nonuniform shear flow with stratified viscosity. Both mean flows are linearly unstable for a range of supersonic Mach numbers (M). For a given M , the critical Reynolds number (Re) is significantly smaller for the uniform shear flow than its nonuniform shear counterpart; for a given Re, the dominant instability (over all streamwise wave numbers, alpha ) of each mean flow belongs to different modes for a range of supersonic M . An analysis of perturbation energy reveals that the instability is primarily caused by an excess transfer of energy from mean flow to perturbations. It is shown that the energy transfer from mean flow occurs close to the moving top wall for "mode I" instability, whereas it occurs in the bulk of the flow domain for "mode II." For the nonmodal transient growth analysis, it is shown that the maximum temporal amplification of perturbation energy, G(max), and the corresponding time scale are significantly larger for the uniform shear case compared to those for its nonuniform counterpart. For alpha=0 , the linear stability operator can be partitioned into L ~ L+Re(2) L(p), and the Re-dependent operator L(p) is shown to have a negligibly small contribution to perturbation energy which is responsible for the validity of the well-known quadratic-scaling law in uniform shear flow: G(t/Re) ~ Re(2). In contrast, the dominance of L(p) is responsible for the invalidity of this scaling law in nonuniform shear flow. An inviscid reduced model, based on Ellingsen-Palm-type solution, has been shown to capture all salient features of transient energy growth of full viscous problem. For both modal and nonmodal instability, it is shown that the viscosity stratification of the underlying mean flow would lead to a delayed transition in compressible Couette flow
On the application of a linearized unsteady potential-flow analysis to fan-tip cascades
NASA Technical Reports Server (NTRS)
Usab, W. J., Jr.; Verdon, J. M.
1986-01-01
A linearized potential flow analysis, which accounts for the effects of nonuniform steady flow phenomena on the unsteady response to prescribed blade motions, has been applied to five two-dimensional cascade configurations. These include a flat-plate cascade and three cascades which are representative of the tip sections of current fan designs. Here the blades are closely spaced, highly staggered, and operate at low mean incidence. The fifth configuration is a NASA Lewis cascade of symmetric biconvex airfoils for which experimental measurements are available. Numerical solutions are presented that clearly illustrate the effects and importance of blade geometry and mean blade loading on the linearized unsteady response at high subsonic inlet Mach number and high blade-vibrational frequency. In addition, a good qualitative agreement is shown between the analytical predictions and experimental measurements for the cascade of symmetric biconvex airfoils. Finally, recommendations on the research needed to extend the range of application of linearized unsteady aerodynamic analyses are provided.
Losses estimation in transonic wet steam flow through linear blade cascade
NASA Astrophysics Data System (ADS)
Dykas, Sławomir; Majkut, Mirosław; Strozik, Michał; Smołka, Krystian
2015-04-01
Experimental investigations of non-equilibrium spontaneous condensation in transonic steam flow were carried out in linear blade cascade. The linear cascade consists of the stator blades of the last stage of low pressure steam turbine. The applied experimental test section is a part of a small scale steam power plant located at Silesian University of Technology in Gliwice. The steam parameters at the test section inlet correspond to the real conditions in low pressure part of 200MWe steam turbine. The losses in the cascade were estimated using measured static pressure and temperature behind the cascade and the total parameters at inlet. The static pressure measurements on the blade surface as well as the Schlieren pictures were used to assess the flow field in linear cascade of steam turbine stator blades.
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.
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.
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
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
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 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 stability analysis and direct numerical simulation of two layer channel flow
NASA Astrophysics Data System (ADS)
Sahu, Kirti; Govindarajan, Rama; Tripathi, Manoj
2015-11-01
We study the stability of two-fluid flow through a plane channel at Reynolds numbers of a hundred to a thousand. The two fluids have the same density but different viscosities. The fluids, when miscible, are separated from each other by a mixed layer of small but finite thickness, across which viscosity changes from that of one fluid to that of the other. When immiscible, the interface is sharp. Our study spans a range of Schmidt numbers, viscosity ratios and location and thickness of the mixed layer. Our two-dimensional linear stability results predict well the behaviour displayed by our three-dimensional direct numerical simulations at early times. In both linear and non-linear regimes, the miscible flow is more unstable than the corresponding immiscible one, and the miscible flow breaks spanwise symmetry more readily to go into three-dimensionality. We show that the miscible flow over our range of parameters is always significantly more unstable than the corresponding immiscible case.
Long-wave linear stability theory for two-fluid channel flow including compressibility effects
NASA Astrophysics Data System (ADS)
Segin, Tetyana M.; Kondic, Lou; Tilley, Burt S.
2006-10-01
We present the linear stability of the laminar flow of an immiscible system of a compressible gas and incompressible liquid separated by an interface with large surface tension in a thin inclined channel. The flow is driven by an applied pressure drop and gravity. Following the air-water case, which is found in a variety of engineering systems, the ratio of the characteristic values of the gas and liquid densities and viscosities are assumed to be disparate. Under the lubrication approximation, and assuming ideal gas behaviour and isothermal conditions, this approach leads to a coupled non-linear system of partial differential equations describing the evolution of the interface between the gas and the liquid and the streamwise density distribution of the gas. This system also includes the effects of viscosity stratification, inertia, shear and capillarity. A linear stability analysis that allows for physically relevant non-zero pressure-drop base state is then performed. In contrast to the zero-pressure drop case which is amenable to the classical normal-mode approach, this configuration requires numerically solving a boundary-value problem for the gas density and interfacial deviations from the base state in the streamwise coordinate. We find that the effect of the gas compressibility on the interfacial stability in the limit of vanishingly small wavenumber is destabilizing, even for Stokes flow in the liquid. However, for finite wavenumber disturbances, compressibility may have stabilizing effects. In this regime, sufficient shear is required to destabilize the flow.
NASA Astrophysics Data System (ADS)
Ding, Yan; Kawahara, Mutsuto
1999-09-01
The linear stability of incompressible flows is investigated on the basis of the finite element method. The two-dimensional base flows computed numerically over a range of Reynolds numbers are perturbed with three-dimensional disturbances. The three-dimensionality in the flow associated with the secondary instability is identified precisely. First, by using linear stability theory and normal mode analysis, the partial differential equations governing the evolution of perturbation are derived from the linearized Navier-Stokes equation with slight compressibility. In terms of the mixed finite element discretization, in which six-node quadratic Lagrange triangular elements with quadratic interpolation for velocities (P2) and three-node linear Lagrange triangular elements for pressure (P1) are employed, a non-singular generalized eigenproblem is formulated from these equations, whose solution gives the dispersion relation between complex growth rate and wave number. Then, the stabilities of two cases, i.e. the lid-driven cavity flow and flow past a circular cylinder, are examined. These studies determine accurately stability curves to identify the critical Reynolds number and the critical wavelength of the neutral mode by means of the Krylov subspace method and discuss the mechanism of instability. For the cavity flow, the estimated critical results are Rec=920.277+/-0.010 for the Reynolds number and kc=7.40+/-0.02 for the wave number. These results are in good agreement with the observation of Aidun et al. and are more accurate than those by the finite difference method. This instability in the cavity is associated with absolute instability [Huerre and Monkewitz, Annu. Rev. Fluid Mech., 22, 473-537 (1990)]. The Taylor-Göertler-like vortices in the cavity are verified by means of the reconstruction of three-dimensional flows. As for the flow past a circular cylinder, the primary instability result shows that the flow has only two-dimensional characteristics at the
Massoudi, M.
2008-01-01
In this paper, we use the classical Mixture Theory and present exact solutions to the equations of motion for the steady flow of two linearly viscous fluids between two horizontal plates. We show that for a saturated mixture and under very special conditions, namely when the body forces are assumed negligible, the only interaction force is due to relative velocity (drag force), and if the two velocities are assumed to be related to each other in a linear fashion, then it is possible to integrate the coupled ordinary differential equations and obtain analytical expressions for the velocities and the volume fraction.
Massoudi, Mehrdad
2008-12-01
In this paper, we use the classical Mixture Theory and present exact solutions to the equations of motion for the steady flow of two linearly viscous fluids between two horizontal plates. We show that for a saturated mixture and under very special conditions, namely when the body forces are assumed negligible, the only interaction force is due to relative velocity (drag force), and if the two velocities are assumed to be related to each other in a linear fashion, then it is possible to integrate the coupled ordinary differential equations and obtain analytical expressions for the velocities and the volume fraction.
Plasma flow in peripheral region of detached plasma in linear plasma device
NASA Astrophysics Data System (ADS)
Hayashi, Y.; Ohno, N.; Kajita, S.; Tanaka, H.
2016-01-01
A plasma flow structure is investigated using a Mach probe under detached plasma condition in a linear plasma device NAGDIS-II. A reverse flow along the magnetic field is observed in a steady-state at far-peripheral region of the plasma column in the upstream side from the recombination front. These experimental results indicate that plasma near the recombination front should strongly diffuse across the magnetic field, and it should be transported along the magnetic field in the reverse flow direction. Furthermore, bursty plasma density fluctuations associated with intermittent convective plasma transport are observed in the far-peripheral region of the plasma column in both upstream and downstream sides from the recombination front. Such a nondiffusive transport can contribute to the intermittent reverse plasma flow, and the experimental results indicate that intermittent transports are frequently produced near the recombination front.
NASA Astrophysics Data System (ADS)
Kranenborg, E. Jurjen; Dijkstra, Henk A.
1995-03-01
Layered double diffusive flow patterns in a laterally heated stably stratified liquid are considered in a configuration which allows for steady states to exist. For the heat/salt system, these flows are characterized by the thermal and solutal Rayleigh numbers RaT and RaS, or equivalently by RaT and the buoyancy ratio Rρ. The bifurcation structure of steady patterns with respect to RaT is computed for two cases: fixed RaS and fixed Rρ. For the first case, results in N. Tsitverblit and E. Kit [Phys. Fluids A 5, 1062 (1993)], are computed and extended, and it is shown that many of the previously found flow patterns are unstable; only in a small interval of RaT, multiple (linearly) stable steady states exist. For the second case, the physical relevance of the unstable steady states with respect to the evolution of the flow toward a stable steady state is demonstrated.
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.
Experimental Analyses of Flow Field Structures around Clustered Linear Aerospike Nozzles
NASA Astrophysics Data System (ADS)
Taniguchi, Mashio; Mori, Hideo; Nishihira, Ryutaro; Niimi, Tomohide
2005-05-01
An aerospike nozzle has been expected as a candidate for an engine of a reusable space shuttle to respond to growing demand for rocket-launching and its cost reduction. In this study, the flow field structures in any cross sections around clustered linear aerospike nozzles are visualized and analyzed, using laser induced fluorescence (LIF) of NO seeded in the carrier gas N2. Since flow field structures are affected mainly by pressure ratio (Ps/Pa, Ps: the source pressure in a reservoir, Pa: the ambient pressure in the vacuum chamber), the clustered linear aerospike nozzle is set inside a vacuum chamber to carry out the experiments in the wide range of pressure ratios from 75 to 200. Flow fields are visualized in several cross-sections, demonstrating the complicated three-dimensional flow field structures. Pressure sensitive paint (PSP) of PtTFPP bound by poly-IBM-co-TFEM is also applied to measurement of the complicated pressure distribution on the spike surface, and to verification of contribution of a truncation plane to the thrust. Finally, to examine the effect of the sidewalls attached to the aerospike nozzle, the flow fields around the nozzle with the sidewalls are compared with those without sidewalls.
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.
Gololobov, G V; Chernova, E A; Schourov, D V; Smirnov, I V; Kudelina, I A; Gabibov, A G
1995-01-01
A highly effective method consisting of two affinity chromatography steps and ion-exchange and gel-filtration chromatography steps was developed for purification of autoantibodies from human sera with DNA-hydrolyzing activity. Antibody Fab fragment, which had been purified 130-fold, was shown to catalyze plasmid DNA cleavage. The flow linear dichroism technique was used for quantitative and qualitative studying of supercoiled plasmid DNA cleavage by these autoantibodies in comparison with DNase I and EcoRI restriction endonuclease. The DNA autoantibody Fab fragment was shown to hydrolyze plasmid DNA by Mg(2+)-dependent single-strand multiple nicking of the substrate. Kinetic properties of the DNA autoantibody Fab fragment were evaluated from the flow linear dichroism and agarose gel electrophoresis data and revealed a high affinity (Kobsm = 43 nM) and considerable catalytic efficiency (kappcat/Kobsm = 0.32 min-1.nM-1) of the reaction. Images Fig. 2 PMID:7816827
Three-dimensional effects of the linear hydrodynamic instability on the plane wake flow
NASA Astrophysics Data System (ADS)
Mele, P.; Morganti, M.; Attili, F.
The LINEAR hydrodynamic stability for plane shear flows considers planar disturbances super-imposed over the main flow. Squire transforms justify the use of disturbances of this kind in order to detect the critical Reynolds number. In this way the behavior of the onset of oscillations of the flow field is well described, especially for flows with a profile of the basic velocity with points of inflexion like wake profile flows. A tentative approach is pursued for the study of the behavior of the flow for a Reynolds number slightly greater than the critical value using the Squire transforms to obtain new solutions of the flow field, with disturbances neither amplified nor damped but of three-dimensional character. The two-dimensional mode is obtained as an eigenfunction of the Orr-Sommerfeld equation by an already tested Galerkin procedure. Hence the Poisson equation is solved in order to obtain the pressure field of the disturbance. The presence of more than one mode is analyzed with their influence on the two- and three-dimensional organized structures of large eddies. Numerical and experimental results are compared.
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 analysis of transient growth in stably-stratified, turbulent channel flow
NASA Astrophysics Data System (ADS)
Del Alamo, Juan Carlos; Yanez, Carlos; Garcia-Villalba, Manuel
2011-11-01
We studied stably-stratified, fully-developed, turbulent channel flow using linear stability analysis. The analysis considered the mean velocity and density profiles extracted from DNS calculations as base flow, and included a linear model to represent the energy dissipation and scalar diffusion felt at the large scales as a consequence of the small scales. The flow was found to be asymptotically stable in all cases but transient growth of initial perturbations was observed. The perturbations showing maximal transient growth corresponded well with spanwise waves in the center of the channel and with streaks in the near wall region, which were both observed in the DNS. In particular, their sizes and convection velocities were reasonably well predicted by the linear model. Component-wise analysis revealed that, while the streaks were formed by the vertical stirring of mean shear, the transient amplification of the spanwise waves was reminiscent of the Orr mechanism. Supporte by the German Research Foundation, Project GA 1360/2-1.
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.
Non-Linear Optical Flow Cytometry Using a Scanned, Bessel Beam Light-Sheet
Collier, Bradley B.; Awasthi, Samir; Lieu, Deborah K.; Chan, James W.
2015-01-01
Modern flow cytometry instruments have become vital tools for high-throughput analysis of single cells. However, as issues with the cellular labeling techniques often used in flow cytometry have become more of a concern, the development of label-free modalities for cellular analysis is increasingly desired. Non-linear optical phenomena (NLO) are of growing interest for label-free analysis because of the ability to measure the intrinsic optical response of biomolecules found in cells. We demonstrate that a light-sheet consisting of a scanned Bessel beam is an optimal excitation geometry for efficiently generating NLO signals in a microfluidic environment. The balance of photon density and cross-sectional area provided by the light-sheet allowed significantly larger two-photon fluorescence intensities to be measured in a model polystyrene microparticle system compared to measurements made using other excitation focal geometries, including a relaxed Gaussian excitation beam often used in conventional flow cytometers. PMID:26021750
Non-linear optical flow cytometry using a scanned, Bessel beam light-sheet.
Collier, Bradley B; Awasthi, Samir; Lieu, Deborah K; Chan, James W
2015-01-01
Modern flow cytometry instruments have become vital tools for high-throughput analysis of single cells. However, as issues with the cellular labeling techniques often used in flow cytometry have become more of a concern, the development of label-free modalities for cellular analysis is increasingly desired. Non-linear optical phenomena (NLO) are of growing interest for label-free analysis because of the ability to measure the intrinsic optical response of biomolecules found in cells. We demonstrate that a light-sheet consisting of a scanned Bessel beam is an optimal excitation geometry for efficiently generating NLO signals in a microfluidic environment. The balance of photon density and cross-sectional area provided by the light-sheet allowed significantly larger two-photon fluorescence intensities to be measured in a model polystyrene microparticle system compared to measurements made using other excitation focal geometries, including a relaxed Gaussian excitation beam often used in conventional flow cytometers. PMID:26021750
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.
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
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.
Corrections to Linear Hall MHD Arising From Heat Flow and Pressure Anisotropy
NASA Astrophysics Data System (ADS)
Tenbarge, Jason
2005-10-01
Previous studies of the solutions to linear Hall MHD have neglected heat flow and pressure anisotropy. Although ignoring these quantities is safe in certain limits, in general heat flow and pressure anisotropy have the potential to play major roles in the evolution of a plasma system. Here we present a study of a two-fluid quasineutral, fully-conductive system with the inclusion of electron heat flow and pressure anisotropy. The ions receive the Chew, Golberger, Low treatment (pressure anisotropy but no heat flow). To include the effects of heat flow and pressure anisotropy, we employ appropriate fluid equations, derived previously by Hazeltine and Mahajan (2002). We find corrections to the standard Hall MHD solutions, from which the standard Hall MHD results presented in Ohsaki and Mahajan (2004) are recoverable when the fluid equations decouple from the equations of motion. 10 R. D. Hazeltine and S. M. Mahajan, Phys. Plasmas 9, 3341 (2002). S. Ohsaki and S. M. Mahajan, Phys. Plasmas 11, 898 (2004).
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.
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.
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.
Performance of a linear robust control strategy on a nonlinear model of spatially developing flows
NASA Astrophysics Data System (ADS)
Lauga, Eric; Bewley, Thomas R.
2004-08-01
This paper investigates the control of self-excited oscillations in spatially developing flow systems such as jets and wakes using {mathcal H}_{infty} control theory on a complex Ginzburg Landau (CGL) model. The coefficients used in this one-dimensional equation, which serves as a simple model of the evolution of hydrodynamic instability waves, are those selected by Roussopoulos & Monkewitz (Physica D 1996, vol. 97, p. 264) to model the behaviour of the near-wake of a circular cylinder. Based on noisy measurements at a point sensor typically located inside the cylinder wake, the compensator uses a linear {mathcal H}_{infty} filter based on the CGL model to construct a state estimate. This estimate is then used to compute linear {mathcal H}_{infty} control feedback at a point actuator location, which is typically located upstream of the sensor. The goal of the control scheme is to stabilize the system by minimizing a weighted average of the ‘system response’ and the ‘control effort’ while rigorously bounding the response of the controlled linear system to external disturbances. The application of such modern control and estimation rules stabilizes the linear CGL system at Reynolds numbers far above the critical Reynolds number Re_c {≈} 47 at which linear global instability appears in the uncontrolled system. In so doing, many unstable modes of the uncontrolled CGL system are linearly stabilized by the single actuator/sensor pair and the model-based feedback control strategy. Further, the linear performance of the closed-loop system, in terms of the relevant transfer function norms quantifying the linear response of the controlled system to external disturbances, is substantially improved beyond that possible with the simple proportional measurement feedback proposed in previous studies. Above Re {≈} 84, the {mathcal H}_{infty} control designs significantly outperform the corresponding {mathcal H}_2 control designs in terms of their ability to stabilize
NASA Astrophysics Data System (ADS)
Cua, Edwin Matthew Chua
The characterization of the low-frequency linear viscoelastic properties of polymers is a classical problem in rheometry, especially for broad molecular weight (MW), fractional melt-flow index (MFI) polyolefins with small time-temperature shift factors. By interconversion of high-temperature, low-shear steady-viscosity data in the terminal flow regime into low-frequency data using the Cox-Merz rule, the experimental window is expanded towards lower frequencies. A squeeze-flow apparatus using Newton interferometry as a drift-free transducer to measure the gap between a spherical lens and a flat glass plate with high spatial resolution was constructed. Trials with a Newtonian silicone oil and a viscoelastic polydimethylsiloxane (PDMS) gum were undertaken to examine the various experimental factors that might contribute to errors in the calculation of the viscosity. After taking into account those factors during the runs with PDMS gum, the squeeze-flow-derived viscosities at the terminal flow regime (at shear rates accessible to a commercial rheometer) were in good agreement with low frequency dynamic data. To achieve much lower shear rates for the runs with polyolefins, an increase in the working gap range was made by switching from Newton interferometry to Fizeau interferometry. A hermetically sealed high vacuum chamber was built to allow high-temperature runs with polyolefins with minimal degradation. Interconversion of the measured viscosities of a broad MW, 1.04 MFI high-density polyethylene (HDPE) with the squeeze flow apparatus resulted in complex viscosity data at ˜10-5 rad/s, expanding the experimental window by 2 decades. The squeeze-flow derived complex viscosity data was used to decide which of the two popular viscosity models was more accurate in predicting the zero-shear rate viscosity based on its fit to dynamic data limited to higher frequencies.
Linear Stability and Nonlinear Evolution of 3D Vortices in Rotating Stratified Flows
NASA Astrophysics Data System (ADS)
Mahdinia, Mani; Hassanzadeh, Pedram; Marcus, Philip
2014-11-01
Axisymmetric Gaussian vortices are widely-used to model oceanic vortices. We study their stability in rotating, stratified flows by using the full Boussinesq equations. We created a stability map as a function of the Burger and Rossby numbers of the vortices. We computed the linear growth rates of the most-unstable eigenmodes and their corresponding eigenmodes. Our map shows a significant cyclone/anti-cyclone asymmetry. The vortices are linearly unstable in most of the parameter space that we studied. However, the anticyclonic vortices, over most of the parameter space, have eigenmodes with only very weak growth rates - longer than 50 vortex turn-around times. For oceanic vortices, that time corresponds to several months, so we argue that this slow growth rate means that the oceanic anticyclones lifetimes are not determined by linear stability, but by other processes. We also use our full, nonlinear simulations to show an example of an unstable cyclone with a very fast growing linear eigenmodes. However, we show that cyclone quickly redistributes its vorticity and becomes a stable tripole with a large core that is nearly axisymmetric.
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.
On linear stability of Rayleigh-Bénard Poiseuille flow of viscoplastic fluids
NASA Astrophysics Data System (ADS)
Métivier, Christel; Nouar, Chérif
2008-10-01
The present paper deals with the onset of the two-dimensional Rayleigh-Bénard convection for a plane channel flow of viscoplastic fluid. The influence of the yield stress on the instability and stability conditions characterized by the Rayleigh numbers denoted, respectively, RaL and RaE is investigated in the framework of linear analysis using modal and energetic approaches. The results show that the yield stress, represented by the Bingham number B, delays the onset of convection. For low values of the Reynolds number Re, the critical conditions RaL and RaE tend to be equal and the difference RaL-RaE increases with increasing Re, highlighting the non-normality of the linear operator. For Re<1 and large B (B ≥O(10)), it is shown that the critical Rayleigh number increases as B2 and the critical wave number evolves according to B1/4.
Non-linear Paradigm for Drift Wave - Zonal Flow interplay: coherence, chaos and turbulence
NASA Astrophysics Data System (ADS)
Zonca, Fulvio
2003-10-01
Non-linear equations for the slow space-time evolution of the radial drift wave (DW) envelope and zonal flow (ZF) amplitude have been self-consistently derived for a model nonuniform tokamak equilibrium within the coherent 4-wave drift wave-zonal flow modulation interaction model of Chen, Lin and White(chen00). For the sake of simplicity, in this work we assume electrostatic fluctuations; but our formalism is readily extended to electromagnetic fluctuations(chen01). In the local limit, i.e. neglecting equilibrium profile variations, the coherent 4-wave DW-ZF modulation interaction model has successfully demonstrated spontaneous generation of ZFs and non-linear DW/ITG-ZF dynamics in toroidal plasmas(chen00). The present work is an extension of previous analyses to allow both (slow) temporal and spatial variations of the DW/ITG radial envelope; thus, it naturally incorporates the effects of equilibrium variations; i.e., turbulence spreading and size-dependence of the saturated wave intensities and transport coefficients(lin99). This approach makes it possible to treat equilibrium profile variations and non-linear interactions on the same footing, assuming that coupling among different DWs on the shortest non-linear time scale is mediated by ZF only. At this level, the competition between linear drive/damping, DW spreading due to finite linear (and nonlinear) group velocity(lin02,chen02,kim02) and non-linear energy transfer between DWs and ZF, determines the saturation levels of the fluctuating fields. Despite the coherence of the underlying non-linear dynamics at this level, this system exhibits both chaotic behavior and intermittency, depending on system size and proximity to marginal stability(chen02). The present model can be further extended to include longer time-scale physics such as 3-wave interactions and collisionless damping of zonal flows. 9 chen00 Liu Chen, Zhihong Lin and Roscoe White, Phys. Plasmas 7, 3129, (2000). chen01 L. Chen, Z. Lin, R.B. White and
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
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.
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
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
Entrainment and mixing dynamics of surface-stress-driven linearly stratified flow in a cylinder
NASA Astrophysics Data System (ADS)
Manucharyan, Georgy; Caulfield, C. P.
2012-11-01
We consider experimentally a linearly stratified fluid (with constant buoyancy frequency N) in a cylinder of depth H subject to surface stress forcing from a disk spinning at constant angular velocity Ω. A turbulent mixed layer develops bounded by a sharp interface of constant thickness. Its depth h / H ~(N / Ω)-2/3(Ωt)x2/9 . We argue this is a consequence of: the kinetic energy of the mixed layer staying constant with time (as previously observed in a two layer flow by Shravat et al. 2012) the entrainment at the interface being governed entirely by local processes; and the rate of increase of the total potential energy of the fluid being dependent only on the global dissipation rate and the ratio N2 /Ω2 . Below the moving primary interface, we also observe in some circumstances the formation of another partially mixed layer, separated by a secondary interface from the linearly stratified fluid below. Depending on the local flow properties, the secondary interfaces can exhibit rich time-dependent dynamics including drift towards or away from the primary interface, merger and/or decay. The secondary interfaces appear to develop due to the non-monotonic dependence of buoyancy flux on stratification as originally argued by Phillips (1972).
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. PMID:26954783
Energy Storage of Linear and Cyclic Electron Flows in Photosynthesis 1
Cha, Yuan; Mauzerall, David C.
1992-01-01
The energy storage of photosynthesis in the green alga Chlorella vulgaris was determined by pulsed, time-resolved photoacoustics. The energy storage of the linear electron transfer process in photosynthesis, of cyclic photosystem (PS) I, and possibly of PSII was determined by selection of excitation wavelength and of flash interval. At 695 nm excitation, a rather large cyclic PSI energy storage of 0.68 ± 0.04 eV/quantum of energy at 8 ms after a 1-μs flash was obtained. This energy remained the same at flash intervals of 0.35 to 60 s and was independent of the presence of 3-(3,4-dichlorophenyl)-1,1-dimethylurea. We tentatively assign this energy to the ferredoxin-NADP-reductase-ferredoxin and oxidized cytochrome b6/f complexes. An efficient distribution of energy between cyclic and linear systems is obtained with the simple assumption that the turnover time of the cyclic system is slower than that of the linear system. The energy storage of linear electron flow was determined by 655 nm excitation of Chlorella with a short flash interval of 0.35 s per flash. It was calculated to be 0.50 ± 0.03 eV/hv, close to that expected for oxygen and NADPH formation. The energy storage of PSII is determined by excitation of Chlorella at 655 nm with a long flash interval of 60 s per flash. It was calculated to be 1.07 ± 0.05 eV/hv, consistent with the energy storage being in S-states and the secondary electron acceptor of PSII with a calculated redox energy of 1.03 eV/hv. In the presence of 1 μm 3-(3,4-dichlorophenyl)-1,1-dimethylurea, the calculated energy storage in PSII is still significant, 0.53 ± 0.04 eV/hv. This probably indicates a significant cyclic electron flow around PSII. These cyclic flows may contribute considerably to energy storage in photosynthesis. PMID:16653211
Linearization of DNA by a squeezing flow in a tunable nanoscale tube: a simulation study
NASA Astrophysics Data System (ADS)
Han, Minsub; Kim, Byoung Choul; Matsuoka, Toshiki; Takayama, Shuichi
2014-03-01
Deoxyribose nucleic acid(DNA) is the biomaterial for storage of genetic information of all living organisms. The linearization of DNA is an initial step in one of the important methods to probe the vital information in biological and clinical settings. Squeezing the solution in flexible nanoscale channel proved to be a highly effective method for fully linearizing DNA (Toshiki et al. Nano Lett 2012). The detailed physical basis of the process is studied by using dissipative particle dynamics simulation, whose results corresponds to the lambda DNA in the nanoscale PDMS channel in the experiment. The squeezing process typically consists of a large degree of elongation by the advective flow, which is followed by recoiling back and adjusting to the narrower confinement. Strong gradient in advection and nanoscale confinement are thus the major thrust for the stretching in the process. The degree of the linearization also depends on the initial position relative to the center in the axial direction as well as the contour length.
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}
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
NASA Astrophysics Data System (ADS)
Saati, Abdulmannan Abdulhamid
1991-02-01
The direct numerical simulation of the stability and transition of compressible Couette flow is studied. The effects of a constant body force along the vertical direction are also studied. Cartesian geometry is adopted to approximate Couette flow produced in the gap between two coaxial cylinders rotating at high-speed, with the body force representing the effects of the centrifugal force. A new, compressible flow solver for two- and three-dimensional, time dependent Navier-Stokes equations, using both the MacCormack and the high-order Two-Four methods was developed. In order to facilitate the simulations with greater detail and accuracy, a high-speed supercomputer with large core memory is required. Thus, the computer code was written in FORTRAN for its execution on the CRAY2, at NASA Langley. In a concurrent effort, in order to study the feasibility and efficiency of massively parallel super-computers and to speed up the computations, the work was further extended by rewriting the computer code in both C* and PARIS languages, for execution on the massively parallel Connection Machine CM 2 at the University of Colorado. Extensive testing of this new computer code was performed using wave propagation problems involving small- and large-amplitude two- and three-dimensional disturbances. Numerical simulations on the stability of compressible Couette flow between two infinite, parallel plates, with the inclusion of (1) a sudden body force, and (2) a body force in equilibrium, were performed. First, two-dimensional disturbances were considered and then the work was extended by considering three-dimensional disturbances on the rectangular Couette flow problem. Effects of body force magnitude, Mach number, and Reynolds number were also investigated. The simulations provide excellent agreement with the linear theory, thus documenting the phase and amplitude accuracy of the computed results; the overall amplitude error remains less than one percent. The results show that
Flow and heat transfer to modified second grade fluid over a non-linear stretching sheet
NASA Astrophysics Data System (ADS)
Khan, Masood; Rahman, Masood ur
2015-08-01
The objective of the present work is to analyze the two-dimensional boundary layer flow and heat transfer of a modified second grade fluid over a non-linear stretching sheet of constant surface temperature. The modelled momentum and energy equations are deduced to a system of ordinary differential equations by employing suitable transformations in boundary layer region and integrated numerically by fourth and fifth order Runge-Kutta Fehlberg method. Additionally, the analytic solutions of the governing problem are presented for some special cases. The secured results make it clear that the power-law index reduces both the momentum and thermal boundary layers. While the incremented values of the generalized second grade parameter leads to an increase in the momentum boundary layer and a decrease in the thermal boundary layer. To see the validity of the present results we have made a comparison with the previously published results as a special case with an outstanding compatibility.
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
NASA Astrophysics Data System (ADS)
Desjardins, T. R.; Gilmore, M.
2016-05-01
Grid biasing is utilized in a large-scale helicon plasma to modify an existing instability. It is shown both experimentally and with a linear stability analysis to be a hybrid drift-Kelvin-Helmholtz mode. At low magnetic field strengths, coherent fluctuations are present, while at high magnetic field strengths, the plasma is broad-band turbulent. Grid biasing is used to drive the once-coherent fluctuations to a broad-band turbulent state, as well as to suppress them. There is a corresponding change in the flow shear. When a high positive bias (10Te) is applied to the grid electrode, a large-scale ( n ˜/n ≈50 % ) is excited. This mode has been identified as the potential relaxation instability.
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.
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.
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).
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
Robust control of linear global instability in models of non-parallel shear flows
NASA Astrophysics Data System (ADS)
Lauga, Eric; Bewley, Thomas
2000-11-01
The present study investigates the control of self-excited oscillations in spatially developing flows such as jets and wakes using H_∞ control theory on a linear complex Ginzburg Landau model. The coefficients of this 1D model equation, which is known to exhibit a generic hydrodynamic instability behavior, are those scaled by Roussopoulos & Monkewitz ( Physica D, 1996) to display behavior modeling that of the near-wake of a circular cylinder, in which a large pocket of local absolute instability is embedded within a convectively unstable flow. Based on noisy measurements at a point sensor typically located inside the wake, the compensator uses an \\cal H_∞ filter to construct a state estimate. This estimate is then used to compute \\cal H_∞ control feedback at a point actuator location, which is typically located upstream of the sensor. The goal of the control scheme is to stabilize the system by minimizing a weighted average of the ``system response'' and the ``control effort'' (both appropriately defined) while rigorously bounding the response of the controlled system to external disturbances. The application of such modern control rules leads to better performance than the control feedback proposed by previous studies by delaying the Reynolds number at which the onset of global instability appears by a factor of 3 and substantially decreasing the sensitivity of the system to external perturbations.
NASA Astrophysics Data System (ADS)
Seo, Jongmin; Bose, Sanjeeb; Garcia-Mayoral, Ricardo; Mani, Ali
2012-11-01
Superhydrophobic surfaces are shown to be effective for surface drag reduction under laminar regime by both experiments and simulations (see for example, Ou and Rothstein, Phys. Fluids 17:103606, 2005). However, such drag reduction for fully developed turbulent flow maintaining the Cassie-Baxter state remains an open problem due to high shear rates and flow unsteadiness of turbulent boundary layer. Our work aims to develop an understanding of mechanisms leading to interface breaking and loss of gas pockets due to interactions with turbulent boundary layers. We take advantage of direct numerical simulation of turbulence with slip and no-slip patterned boundary conditions mimicking the superhydrophobic surface. In addition, we capture the dynamics of gas-water interface, by deriving a proper linearized boundary condition taking into account the surface tension of the interface and kinematic matching of interface deformation and normal velocity conditions on the wall. We will show results from our simulations predicting the dynamical behavior of gas pocket interfaces over a wide range of dimensionless surface tensions. Supported by the Office of Naval Research and the Kwanjeong Educational Scholarship Foundation.
NASA Astrophysics Data System (ADS)
Hill, P.; Saarelma, S.; McMillan, B.; Peeters, A.; Verwichte, E.
2012-06-01
Sheared E × B flows are known to stabilize turbulence. This paper investigates how the linear stability of the ion-temperature-gradient (ITG) mode depends on k⊥ in both circular and MHD geometry. We study the effects of both rotation profiles of constant shear and of purely toroidal flow taken from experiment, using the global gyrokinetic particle-in-cell code NEMORB. We find that in order to effectively stabilize the linear mode, the fastest growing mode requires a shearing rate (γE) around 1-2 times its linear growth rate without flow (γ0), while both longer and shorter wavelength modes need much larger flow shear compared with their static linear growth rates. Modes with kθρi < 0.2 need γE as much as 10 times their γ0. This variation exists in both large-aspect ratio circular cross-section and small-aspect ratio MHD geometries, with both analytic constant shear and experimental flow profiles. There is an asymmetry in the suppression with respect to the sign of γE, due to competition between equilibrium profile variation and flow shear. The maximum growth rate for cases using the experimental profile in MAST equilibria occurs at shearing rates of 10% the experimental level.
NASA Astrophysics Data System (ADS)
Blanchard, M.; Schuller, T.; Sipp, D.; Schmid, P. J.
2015-04-01
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.
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.
Tandon, P; Diamond, S L
1997-01-01
We have modeled platelet aggregation in a linear shear flow by accounting for two body collision hydrodynamics, platelet activation and receptor biology. Considering platelets and their aggregates as unequal-sized spheres with DLVO interactions (psi(platelet) = -15 mV, Hamaker constant = 10(-19) J), detailed hydrodynamics provided the flow field around the colliding platelets. Trajectory calculations were performed to obtain the far upstream cross-sectional area and the particle flux through this area provided the collision frequency. Only a fraction of platelets brought together by a shearing fluid flow were held together if successfully bound by fibrinogen cross-bridging GPIIb/IIIa receptors on the platelet surfaces. This fraction was calculated by modeling receptor-mediated aggregation using the formalism of Bell (Bell, G. I. 1979. A theoretical model for adhesion between cells mediated by multivalent ligands. Cell Biophys. 1:133-147) where the forward rate of bond formation dictated aggregation during collision and was estimated from the diffusional limited rate of lateral association of receptors multiplied by an effectiveness factor, eta, to give an apparent rate. For a value of eta = 0.0178, we calculated the overall efficiency (including both receptor binding and hydrodynamics effects) for equal-sized platelets with 50,000 receptors/platelet to be 0.206 for G = 41.9 s(-1), 0.05 for G = 335 s(-1), and 0.0086 for G = 1920 s(-1), values which are in agreement with efficiencies determined from initial platelet singlet consumption rates in flow through a tube. From our analysis, we predict that bond formation proceeds at a rate of approximately 0.1925 bonds/microm2 per ms, which is approximately 50-fold slower than the diffusion limited rate of association. This value of eta is also consistent with a colloidal stability of unactivated platelets at low shear rates. Fibrinogen was calculated to mediate aggregation quite efficiently at low shear rates but not at
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 Astrophysics Data System (ADS)
Abgrall, Rémi; Congedo, Pietro Marco
2013-02-01
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
NASA Astrophysics Data System (ADS)
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
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)
Shang, Yu; Yu, Guoqiang
2014-09-01
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., αDB). 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 αDB in the brain layer with a step decrement of 10% while maintaining αDB 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)
AMABILI, M.; PELLICANO, F.; PAÏDOUSSIS, M. P.
2000-11-01
The response of a shell conveying fluid to harmonic excitation, in the spectral neighbourhood of one of the lowest natural frequencies, is investigated for different flow velocities. The theoretical model has already been presented in Part I of the present study. Non-linearities due to moderately large-amplitude shell motion are considered by using Donnell's non-linear shallow-shell theory. Linear potential flow theory is applied to describe the fluid-structure interaction by using the model proposed by Paı̈doussis and Denise. For different amplitudes and frequencies of the excitation and for different flow velocities, the following are investigated numerically: (1) periodic response of the system; (2) unsteady and stochastic motion; (3) loss of stability by jumps to bifurcated branches. The effect of the flow velocity on the non-linear periodic response of the system has also been investigated. Poincaré maps and bifurcation diagrams are used to study the unsteady and stochastic dynamics of the system. Amplitude modulated motions, multi-periodic solutions, chaotic responses, cascades of bifurcations as the route to chaos and the so-called “blue sky catastrophe” phenomenon have all been observed for different values of the system parameters; the latter two have been predicted here probably for the first time for the dynamics of circular cylindrical shells.
Several series of experiments were performed in a stratified towing tank to study the near-field flow of a linearly stratified fluid over an isolated three-dimensional hill. he streamlines were obtained in the laboratory using a stereographic method to determine the paths of plum...
NASA Astrophysics Data System (ADS)
Xu, Xiaolei; Chen, Jizhong; An, Lijia
2014-05-01
The properties of both untangled and entangled linear polymer melts under shear flow are studied by nonequilibrium molecular dynamics simulations. The results reveal that the dependence of shear viscosity η on shear rate dot{γ }, expressed by η ˜ dot{γ }^{-n}, exhibits three distinct regimes. The first is the well-known Newtonian regime, namely, η independent of shear rate at small shear rates dot{γ }<τ 0^{-1} (where τ0 is the longest polymer relaxation time at equilibrium). In the non-Newtonian regime (dot{γ }>τ 0^{-1}), the shear dependence of viscosity exhibits a crossover at a critical shear rate dot{γ }c dividing this regime into two different regimes, shear thinning regime I (ST-I) and II (ST-II), respectively. In the ST-I regime (τ ^{-1}_0
NASA Astrophysics Data System (ADS)
Narayanan, S.; Sekar, P.
1995-07-01
The response of a single-degree-of-freedom (sdf) vibrating system with unsymmetrical piecewise linear stiffness subjected to combined harmonic and flow induced excitations is investigated. Motion limiting stops, different tension and compression behavior, etc., may introduce an unsymmetrical piecewise linear stiffness characteristic. A multi-harmonic balance cum Newton-Raphson procedure in conjunction with an FFT algorithm is adopted to determine the stable and unstable periodic solutions. The stability of the periodic solutions is investigated by using Floquet theory. Digital simulation results reveal periodic, quasi-periodic and chaotic motions of the system in a range of flow velocities. Mode locked oscillations with period 5 motions are found to occur in certain range of flow velocities. Bifurcation diagrams and Lyapunov exponents are also presented.
Making Routine Letters Have Positive Effects.
ERIC Educational Resources Information Center
Walsh, S. M.
While few business people dispute the importance of carefully crafting persuasive, demanding, conciliatory, and bad-news letters, the regular flow of routine communications receives very little meaningful consideration or scrutiny. These routine communications (letters, inquiries, requests, collection letters, complaints, confirmations,…
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.
Investigation of Flow Separation in a Transonic-fan Linear Cascade Using Visualization Methods
NASA Technical Reports Server (NTRS)
Lepicovsky, Jan; Chima, Rodrick V.; Jett, Thomas A.; Bencic, Timothy J.; Weiland, Kenneth E.
2000-01-01
An extensive study into the nature of the separated flows on the suction side of modem transonic fan airfoils at high incidence is described in the paper. Suction surface.flow separation is an important flow characteristic that may significantly contribute to stall flutter in transonic fans. Flutter in axial turbomachines is a highly undesirable and dangerous self-excited mode of blade oscillations that can result in high cycle fatigue blade failure. The study basically focused on two visualization techniques: surface flow visualization using dye oils, and schlieren (and shadowgraph) flow visualization. The following key observations were made during the study. For subsonic inlet flow, the flow on the suction side of the blade is separated over a large portion of the blade, and the separated area increases with increasing inlet Mach number. For the supersonic inlet flow condition, the flow is attached from the leading edge up to the point where a bow shock from the upper neighboring blade hits the blade surface. Low cascade solidity, for the subsonic inlet flow, results in an increased area of separated flow. For supersonic flow conditions, a low solidity results in an improvement in flow over the suction surface. Finally, computational results modeling the transonic cascade flowfield illustrate our ability to simulate these flows numerically.
NASA Astrophysics Data System (ADS)
Abdusslam, Saleh N.; Chit, Ong J.; Hamdan, Megat M.; Omar, Ashraf A.; Asrar, Waqar
2006-12-01
Fluid flows within turbomachinery tend to be extremely complex. Understanding such flows is crucial in the effort to improve current turbomachinery designs. Hence, computational approaches can be used to great advantage in this regard. In this paper, gas-kinetic BGK (Bhatnagar-Gross-Krook) scheme is developed for simulating compressible inviscid flow around a linear turbine cascade. BGK scheme is an approximate Riemann solver that uses the collisional Boltzmann equation as the governing equation for flow evolutions. For efficient computations, particle distribution functions in the general solution of the BGK model are simplified and used for the flow simulations. Second-order accuracy is achieved via the reconstruction of flow variables using the MUSCL (Monotone Upstream-Centered Schemes for Conservation Laws) interpolation technique together with a multistage Runge-Kutta method. A multi-zone H-type mesh for the linear turbine cascades is generated using a structured algebraic grid generation method. Computed results are compared with available experimental data and found to be in agreement with each other. In order to further substantiate the performance of the BGK scheme, another test case, namely a wedge cascade, is used. The numerical solutions obtained via this test are validated against analytical solutions, which showed to be in good agreement.
NASA Astrophysics Data System (ADS)
Sethi, Rajandrea
2011-03-01
SummaryIn this study a method based on dual-well step drawdown test (i.e. a combination of an aquifer and a well performance test) for the determination of hydrodynamic parameters (namely storage coefficient and hydraulic conductivity), mechanical wellbore finite thickness skin factor, non-linear wellbore and non-linear aquifer parameters in an homogeneous confined aquifer is presented in order to put together aquifer and well tests. The interpretation procedure is based on the application of superposition principle to a large time logarithmic approximation of the solution. The advantages of this method, that can be considered an extension of Jacob step-test (1947) and Cooper-Jacob approximation (1946), are that: (I) it is possible to determine simultaneously aquifer and well properties in a single test; (II) the method is based on a large time approximation and it is therefore independent from wellbore storage; (III) if the well skin is absent, the aquifer parameters (storage coefficient and hydraulic conductivity) can be derived just from a single-well test; (IV) the interpretation procedure is easy to apply and robust and does not require any specific numeric code or software. The same procedure can be easily adapted to gas well testing. It is also shown that, even in the presence of linear and non-linear flow, skin effect and wellbore storage, the hydraulic conductivity (and not the storage coefficient) of the aquifer can be correctly estimated by the Cooper and Jacob (1946) method applied to a single-rate pumping test, using exclusively the large time drawdown data measured at the pumping well.
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
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
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
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.
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)
Routines for Computing Pressure Drops in Venturis
NASA Technical Reports Server (NTRS)
de Quay, Laurence
2004-01-01
A set of computer-program routines has been developed for calculating pressure drops and recoveries of flows through standard venturis, nozzle venturis, and orifices. Relative to prior methods used for such calculations, the method implemented by these routines offers greater accuracy because it involves fewer simplifying assumptions and is more generally applicable to wide ranges of flow conditions. These routines are based on conservation of momentum and energy equations for real nonideal fluids, the properties of which are calculated by curve-fitting subroutines based on empirical properties data. These routines are capable of representing cavitating, choked, non-cavitating, and unchoked flow conditions for liquids, gases, and supercritical fluids. For a computation of flow through a given venturi, nozzle venturi, or orifice, the routines determine which flow condition occurs: First, they calculate a throat pressure under the assumption that the flow is unchoked or non-cavitating, then they calculate the throat pressure under the assumption that the flow is choked or cavitating. The assumption that yields the higher throat pressure is selected as the correct one.
NASA Astrophysics Data System (ADS)
Clarisse, Jean-Marie; Jaouen, Stéphane; Raviart, Pierre-Arnaud
2004-07-01
Linear stability studies of complex flows require that efficient numerical methods be devised for predicting growth rates of multi-dimensional perturbations. For one-dimensional (1D) basic flows - i.e. of planar, cylindrical or spherical symmetry - a general numerical approach is viable which consists in solving simultaneously the one-dimensional equations of gas dynamics and their linearized forms for three-dimensional perturbations. Extensions of artificial viscosity methods have thus been used in the past. More recently [Equations aux dérivées partielles et applications, articles dédiés à J.-L. Lions, 1998], Godunov-type schemes for single-fluid flows of gas dynamics and magnetohydrodynamics have been proposed. Pursuing this effort, we introduce, within the Lagrangian perturbation approach, a class of Godunov-type schemes which is well suited for solving multi-material problems of gas dynamics. These schemes are developed here for the planar-symmetric case and comprise two second-order extensions. The numerical capabilities of these methods are illustrated by computations of Richtmyer-Meshkov instabilities occurring at a single material interface. A systematic comparison of numerically computed growth rates with results of the linear theory for the Richtmyer-Meshkov instability is provided.
Data format translation routines
Burris, R.D.
1981-02-01
To enable the effective connection of several dissimilar computers into a network, modification of the data being passed from one computer to another may become necessary. This document describes a package of routines which permit the translation of data in PDP-8 formats to PDP-11 or DECsystem-10 formats or from PDP-11 format to DECsystem-10 format. Additional routines are described which permit the effective use of the translation routines in the environment of the Fusion Energy Division (FED) network and the Elmo Bumpy Torus (EBT) data base.
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.
NASA Astrophysics Data System (ADS)
El-Batsh, Hesham
The flow field through a transonic linear turbine cascade is studied in this paper at design and off-design conditions. The compressible flow field is obtained by solving the equations governing the fluid flow and heat transfer. Two eddy-viscosity turbulence models are used to simulate the turbulence in turbine cascades: the standard k-e model and the Spalart Allmaras model. The standard k-e model is the most universal and popular model for industrial flow and heat transfer simulations. It has the shortcoming of accurately predicting the profile loss in turbomachinery applications. The Spalart Allmaras model is a relatively recent and simple one-equation model. In this paper, the model is tested for turbomachinery applications. The ability of the model to accurately predict the flow field in turbine cascade is tested. Blade loading, downstream wake distribution, total pressure loss coefficient, and exit flow angle are used in this study with comparisons to the standard k-e model and experimental data. The design condition and the off-design conditions are considered.
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.
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 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.
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 ...
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
Study of Separation and Transition of Boundary Layer For Flow Through Linear Turbine Cascade
NASA Astrophysics Data System (ADS)
Mutnuri, Pavan Kumar; Ayyalasomayajula, Haritha; Ghia, Urmila; "Karman" Ghia, Kirti
2002-11-01
The objective of the present work is to study the boundary-layer separation of unsteady flow in turbomachines. A parallel, Chimera version of FDL3DI is used as the flow solver. The code uses second and fourth-order damping for a stable numerical solution. The use of fourth-order damping terms necessitates a minimum of 4-cell overlap at inter-block boundaries. The extended overlap is also necessary for the later intended use of a higher-order accurate differencing technique. The blocks are extended in such a way that the grid points in the overlap region coincide with the grid points in the neighboring-block (under-lapping) region and hence direct injection may be used for inter-block communication. This maintains the order of accuracy of the difference scheme; otherwise, any interpolation involved in inter-block communication needs to be of the same high-order accuracy as the difference scheme of the flow equations. PEGASUS is used to update the flow variables at the block interfaces. A 12-block structured grid of multiple topologies generated by GRIDPRO is used. Low-Re separated flow results are examined and will be presented for a cascade configuration. Passive control methodology is also planned for application to unsteady boundary-layer flow separation in the cascade.
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.
Effect of Coannular Flow on Linearized Euler Equation Predictions of Jet Noise
NASA Technical Reports Server (NTRS)
Hixon, R.; Shih, S.-H.; Mankbadi, Reda R.
1997-01-01
An improved version of a previously validated linearized Euler equation solver is used to compute the noise generated by coannular supersonic jets. Results for a single supersonic jet are compared to the results from both a normal velocity profile and an inverted velocity profile supersonic jet.
Particle behavior in linear shear flow: an experimental and numerical study
NASA Astrophysics Data System (ADS)
Fathi, Nima; Ingber, Marc; Vorobieff, Peter
2012-11-01
We study particle behavior in low Reynolds number flows. Our experimental setup can produce both Couette flow and Pouseuille flow at low Reynolds numbers. Spherical particles are suspended in gravity-stratified Newtonian fluid. Their predominantly two-dimensional motion is driven by moving belts (and/or piston) that produce shear in the fluids. Particle migration and translational velocity have been studied. The irreversibility of particle motion has been investigated. The experimental results are compared to the numerical simulations performed with discrete phase element method (DPM). Particle trajectories with the same boundary conditions in viscous fluids have been studied. The irreversibility in numerical simulation has been modeled for different cases. Results show the particle migration is a function of shear rate, particle size, degree of symmetry of the fluid domain, and also of the initial starting position, the latter playing an important role in the irreversibility of particle motion. This research is partly supported by Procter & Gamble.
Khan, Junaid Ahmad; Mustafa, Meraj; Hayat, Tasawar; Alsaedi, Ahmed
2014-01-01
This article studies the viscous flow and heat transfer over a plane horizontal surface stretched non-linearly in two lateral directions. Appropriate wall conditions characterizing the non-linear variation in the velocity and temperature of the sheet are employed for the first time. A new set of similarity variables is introduced to reduce the boundary layer equations into self-similar forms. The velocity and temperature distributions are determined by two methods, namely (i) optimal homotopy analysis method (OHAM) and (ii) fourth-fifth-order Runge-Kutta integration based shooting technique. The analytic and numerical solutions are compared and these are found in excellent agreement. Influences of embedded parameters on momentum and thermal boundary layers are sketched and discussed. PMID:25198696
Khan, Junaid Ahmad; Mustafa, Meraj; Hayat, Tasawar; Alsaedi, Ahmed
2014-01-01
This article studies the viscous flow and heat transfer over a plane horizontal surface stretched non-linearly in two lateral directions. Appropriate wall conditions characterizing the non-linear variation in the velocity and temperature of the sheet are employed for the first time. A new set of similarity variables is introduced to reduce the boundary layer equations into self-similar forms. The velocity and temperature distributions are determined by two methods, namely (i) optimal homotopy analysis method (OHAM) and (ii) fourth-fifth-order Runge-Kutta integration based shooting technique. The analytic and numerical solutions are compared and these are found in excellent agreement. Influences of embedded parameters on momentum and thermal boundary layers are sketched and discussed. PMID:25198696
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.
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.
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.
Modin, A Iu
2002-01-01
Effects of gravity on linear blood velocity in jugular, femoral and popliteal veins were examined in 45 healthy male and female subjects. The zero-g effects were simulated by putting the subjects in the recumbent position, and the gravity effects were provoked by active orthostasis. Blood velocity was measured with CW Doppler (4 MHz). No difference was determined in velocity of the blood flow along the veins in recumbent subjects. In the head-up position, blood flow was significantly increased in the jugular vein and decreased in the leg veins. In several instances, brief contraction of the crus muscles caused a noticeable rise in the peak velocity along the femoral vein. In the head-up position this hemodynamic effect of the crus pump was much more pronounced. PMID:12098950
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).
NASA Astrophysics Data System (ADS)
Jiang, Shidong; Luo, Li-Shi
2016-07-01
The integral equation for the flow velocity u (x ; k) in the steady Couette flow derived from the linearized Bhatnagar-Gross-Krook-Welander kinetic equation is studied in detail both theoretically and numerically in a wide range of the Knudsen number k between 0.003 and 100.0. First, it is shown that the integral equation is a Fredholm equation of the second kind in which the norm of the compact integral operator is less than 1 on Lp for any 1 ≤ p ≤ ∞ and thus there exists a unique solution to the integral equation via the Neumann series. Second, it is shown that the solution is logarithmically singular at the endpoints. More precisely, if x = 0 is an endpoint, then the solution can be expanded as a double power series of the form ∑n=0∞∑m=0∞cn,mxn(xln x) m about x = 0 on a small interval x ∈ (0 , a) for some a > 0. And third, a high-order adaptive numerical algorithm is designed to compute the solution numerically to high precision. The solutions for the flow velocity u (x ; k), the stress Pxy (k), and the half-channel mass flow rate Q (k) are obtained in a wide range of the Knudsen number 0.003 ≤ k ≤ 100.0; and these solutions are accurate for at least twelve significant digits or better, thus they can be used as benchmark solutions.
Bohling, G.C.; Butler, J.J., Jr.
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.
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.
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.
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.
PROPER: Optical propagation routines
NASA Astrophysics Data System (ADS)
Krist, John E.
2014-05-01
PROPER simulates the propagation of light through an optical system using Fourier transform algorithms (Fresnel, angular spectrum methods). Distributed as IDL source code, it includes routines to create complex apertures, aberrated wavefronts, and deformable mirrors. It is especially useful for the simulation of high contrast imaging telescopes (extrasolar planet imagers like TPF).
Routine neonatal circumcision?
Tran, P. T.; Giacomantonio, M.
1996-01-01
Routine neonatal circumcision is still a controversial procedure. This article attempts to clarify some of the advantages and disadvantages of neonatal circumcision. The increased rate of penile cancer among uncircumcised men appears to justify the procedure, but that alone is not sufficient justification. The final decision on neonatal circumcision should be made by parents with balanced counsel from attending physicians. PMID:8939321
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
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. PMID:26421429
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.
The piecewise-linear predictor-corrector code - A Lagrangian-remap method for astrophysical flows
NASA Technical Reports Server (NTRS)
Lufkin, Eric A.; Hawley, John F.
1993-01-01
We describe a time-explicit finite-difference algorithm for solving the nonlinear fluid equations. The method is similar to existing Eulerian schemes in its use of operator-splitting and artificial viscosity, except that we solve the Lagrangian equations of motion with a predictor-corrector and then remap onto a fixed Eulerian grid. The remap is formulated to eliminate errors associated with coordinate singularities, with a general prescription for remaps of arbitrary order. We perform a comprehensive series of tests on standard problems. Self-convergence tests show that the code has a second-order rate of convergence in smooth, two-dimensional flow, with pressure forces, gravity, and curvilinear geometry included. While not as accurate on idealized problems as high-order Riemann-solving schemes, the predictor-corrector Lagrangian-remap code has great flexibility for application to a variety of astrophysical problems.
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.
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.
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.
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.
Saitou, Y.; Yonesu, A.; Shinohara, S.; Ignatenko, M. V.; Kasuya, N.; Kawaguchi, M.; Terasaka, K.; Nishijima, T.; Nagashima, Y.; Kawai, Y.; Yagi, M.; Itoh, S.-I.; Azumi, M.; Itoh, K.
2007-07-15
The importance of reducing the neutral density to reach strong drift wave turbulence is clarified from the results of the extended magnetohydrodynamics and Monte Carlo simulations in a linear magnetized plasma. An upper bound of the neutral density relating to the ion-neutral collision frequency for the excitation of drift wave instability is shown, and the necessary flow velocity to excite this instability is also estimated from the neutral distributions. Measurements of the Mach number and the electron density distributions using Mach probe in the large mirror device (LMD) of Kyushu University [S. Shinohara et al., Plasma Phys. Control. Fusion 37, 1015 (1995)] are reported as well. The obtained results show a controllability of the neutral density and provide the basis for neutral density reduction and a possibility to excite strong drift wave turbulence in the LMD.
NASA Astrophysics Data System (ADS)
Sahu, Kirti; Valluri, Prashant; Spelt, Peter; Matar, Omar
2007-11-01
The linear stability of pressure-driven channel flow of a Newtonian layer past a non-Newtonian fluid is studied; the latter is assumed to possess a finite yield stress and to exhibit a power-law behaviour. Coupled Orr-Sommerfeld-type eigenvalue equations are derived and solved using a spectral collocation method in the absence of unyielded regions. The numerical solutions of these equations are in agreement with analytical predictions valid in the long-wave limit. Our results indicate that increasing the yield stress (prior to the formation of unyielded regions) and shear thickening tendency of the non-Newtonian fluid promote instability. An analysis of the disturbance `energy' illustrates the presence of an unstable, `interfacial' mode at all Reynolds numbers studied, and an additional, less unstable `shear' mode at relatively high Reynolds numbers. The influence of non-Newtonian rheology on the stability characteristics of these modes is elucidated.
Linear instability of pressure-driven channel flow of a Newtonian and a Herschel-Bulkley fluid
NASA Astrophysics Data System (ADS)
Sahu, K. C.; Valluri, P.; Spelt, P. D. M.; Matar, O. K.
2007-12-01
The linear stability characteristics of pressure-driven two-layer channel flow are considered, wherein a Newtonian fluid layer overlies a layer of a Herschel-Bulkley fluid. A pair of coupled Orr-Sommerfeld eigenvalue equations are derived and solved using an efficient spectral collocation method for cases in which unyielded regions are absent. An asymptotic analysis is also carried out in the long-wave limit, the results of which are in excellent agreement with the numerical predictions. Our analytical and numerical results indicate that increasing the dimensionless yield stress, prior to the formation of unyielded plugs below the interface, is destabilizing. Increasing the shear-thinning tendency of the lower fluid is stabilizing.
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)
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.
NASA Astrophysics Data System (ADS)
Chou, F. N.-F.; Wu, C.-W.
2014-05-01
This paper presents a method to establish the objective function of a network flow programming model for simulating river-reservoir system operations and associated water allocation, with an emphasis on situations when the links other than demand or storage have to be assigned with nonzero cost coefficients. The method preserves the priorities defined by rule curves of reservoir, operational preferences for conveying water, allocation of storage among multiple reservoirs, and transbasin water diversions. Path enumeration analysis transforms these water allocation rules into linear constraints that can be solved to determine link cost coefficients. An approach to prune the original system into a reduced network is proposed to establish the precise constraints of nonzero cost coefficients, which can then be efficiently solved. The cost coefficients for the water allocation in the Feitsui and Shihmen reservoirs' joint operating system of northern Taiwan was adequately assigned by the proposed method. This case study demonstrates how practitioners can correctly utilize network-flow-based models to allocate water supply throughout complex systems that are subject to strict operating rules.
NASA Astrophysics Data System (ADS)
Chou, F. N.-F.; Wu, C.-W.
2013-12-01
This paper presents a method to establish the objective function of a network flow programming model for simulating river/reservoir system operations and associated water allocation, with an emphasis on situations when the links other than demand or storage have to be assigned with nonzero cost coefficients. The method preserves the priorities defined by rule curves of reservoir, operational preferences for conveying water, allocation of storage among multiple reservoirs, and trans-basin water diversions. Path enumeration analysis transforms these water allocation rules into linear constraints that can be solved to determine link cost coefficients. An approach to prune the original system into a reduced network is proposed to establish the precise constraints of nonzero cost coefficients which can then be efficiently solved. The cost coefficients for the water allocation in the Feitsui and Shihmen Reservoirs joint operating system of northern Taiwan was adequately assigned by the proposed method. This case study demonstrates how practitioners can correctly utilize network-flow-based models to allocate water supply throughout complex systems that are subject to strict operating rules.
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. PMID:16494250
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. PMID:26066258
... own by filling gallon milk jugs with water. Warm up. Get your blood flowing by walking in place. ... prevent some injuries. You should continue with your warm up until your body feels warm and you are ...
CALIPSO User-Provided Routines
Atmospheric Science Data Center
2013-04-01
... data files. These routines are written in Interactive Data Language (IDL). A README file demonstrating use of the routines is also available. Interactive Data Language (IDL) is available from Exelis Visual Information Solutions . ...
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.
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.
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.
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
NASA Astrophysics Data System (ADS)
Khosid, S.; Tambour, Y.
A novel modification of the classical Langhaar linearization of the mutually coupled momentum equations for developing two-phase flows in circular ducts is presented. This modification enables us to treat: (i) flows developing from spatially periodic initial velocity distributions without the presence of droplets, and (ii) two-phase flows in which monosize, non-evaporating and evaporating droplets suspended in a developing gas flow of an initially uniform velocity distribution exchange momentum with the host-gas flow. New solutions are presented for the downstream evolution in the velocity profiles which develop from spatially periodic initial velocity distributions that eventually reach the fully developed Poiseuille velocity profile. These solutions are validated by employing known numerical procedures, providing strong support for the physical underpinnings of the present modified linearization. New solutions are also presented for the evolution in drop velocities and vapour spatial distributions for evaporating droplets suspended in an initially uniform velocity profile of the host gas. Asymptotic solutions are presented for the flow region which lies very close to the inlet of the tube, where the relative velocity between the droplets and the host gas is high, and thus the velocity fields of the two phases are mutually coupled. These solutions provide new explicit formulae for the droplet velocity field as a function of the initial conditions and droplet diameter (relative to the tube diameter) for non-evaporating drops, and also as a function of evaporation rate for evaporating drops.
Lidar Altitude Data Read Routine
Atmospheric Science Data Center
2013-03-19
... Profile products. It is written in Interactive Data Language (IDL) and uses HDF routine calls to read the altitude data which are ... Data Read routine (1.5 KB) Interactive Data Language (IDL) is available from Exelis Visual Information Solutions . ...
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.
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 Technical Reports Server (NTRS)
Tyson, R. W.; Muraca, R. J.
1975-01-01
The local linearization method for axisymmetric flow is combined with the transonic equivalence rule to calculate pressure distribution on slender bodies at free-stream Mach numbers from .8 to 1.2. This is an approximate solution to the transonic flow problem which yields results applicable during the preliminary design stages of a configuration development. The method can be used to determine the aerodynamic loads on parabolic arc bodies having either circular or elliptical cross sections. It is particularly useful in predicting pressure distributions and normal force distributions along the body at small angles of attack. The equations discussed may be extended to include wing-body combinations.
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)
Zillinger, Christian
2016-03-01
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)
Esmaily-Moghadam, M.; Bazilevs, Y.; Marsden, A. L.
2015-01-01
A parallel data structure that gives optimized memory layout for problems involving iterative solution of sparse linear systems is developed, and its efficient implementation is presented. The proposed method assigns a processor to a problem subdomain, and sorts data based on the shared entries with the adjacent subdomains. Matrix-vector-product communication overhead is reduced and parallel scalability is improved by overlapping inter-processor communications and local computations. The proposed method simplifies the implementation of parallel iterative linear equation solver algorithms and reduces the computational cost of vector inner products and matrix-vector products. Numerical results demonstrate very good performance of the proposed technique.
NASA Astrophysics Data System (ADS)
Ghopa, Wan Aizon W.; Harun, Zambri; Funazaki, Ken-ichi; Miura, Takemitsu
2015-02-01
The existence of a gap between combustor and turbine endwall in the real gas turbine induces to the leakages phenomenon. However, the leakages could be used as a coolant to protect the endwall surfaces from the hot gas since it could not be completely prevented. Thus, present study investigated the potential of leakage flows as a function of film cooling. In present study, the flow field at the downstream of high-pressure turbine blade has been investigated by 5-holes pitot tube. This is to reveal the aerodynamic performances under the influenced of leakage flows while the temperature measurement was conducted by thermochromic liquid crystal (TLC). Experimental has significantly captured theaerodynamics effect of leakage flows near the blade downstream. Furthermore, TLC measurement illustrated that the film cooling effectiveness contours were strongly influenced by the secondary flows behavior on the endwall region. Aero-thermal results were validated by the numerical simulation adopted by commercial software, ANSYS CFX 13. Both experimental and numerical simulation indicated almost similar trendinaero and also thermal behavior as the amount of leakage flows increases.
Collie, J.C.; Moses, H.L.; Schetz, J.A. ); Gregory, B.A. . Turbine Aero and Cooling Technology)
1993-10-01
High-pressure-ratio turbines have flows dominated by shock structures that pass downstream into the next blade row in an unsteady fashion. Recent numerical results have indicated that these unsteady shocks may significantly affect the aerodynamic and mechanical performance of turbine blading. High cost and limited accessibility of turbine rotating equipment severely restrict the quantitative evaluation of the unsteady flow field in that environment. Recently published results of the Virginia Tech transonic cascade facility indicate high integrity in simulation of the steady state flow phenomena. The facility has recently been modified to study the unsteady effects of passing shock waves. Shock waves are generated by a shotgun blast upstream of the blade row. Shadowgraph photos and high-response pressure data are compared to previously published experimental and numerically predicted results. Plots are included that indicate large fluctuations in estimated blade lift and cascade loss.
NASA Astrophysics Data System (ADS)
AMABILI, M.; PELLICANO, F.; PAÏDOUSSIS, M. P.
1999-12-01
The non-linear response of empty and fluid-filled circular cylindrical shells to harmonic excitations is investigated. Both modal and point excitations have been considered. The model is suitable to study simply supported shells with and without axial constraints. Donnell's non-linear shallow-shell theory is used. The boundary conditions on radial displacement and the continuity of circumferential displacement are exactly satisfied. The radial deflection of the shell is expanded by using a basis of seven linear modes. The effect of internal quiescent, incompressible and inviscid fluid is investigated. The equations of motion, obtained in Part I of this study, are studied by using a code based on the collocation method. The validation of the present model is obtained by comparison with other authoritative results. The effect of the number of axisymmetric modes used in the expansion on the response of the shell is investigated, clarifying questions open for a long time. The results show the occurrence of travelling wave response in the proximity of the resonance frequency, the fundamental role of the first and third axisymmetric modes in the expansion of the radial deflection with one longitudinal half-wave, and limit cycle responses. Modes with two longitudinal half-waves are also investigated.
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.
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 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
MISR Conversion to ASCII Routines
Atmospheric Science Data Center
2013-04-01
... These routines are written in Exelis Visual Information Solutions IDL programming language. They can be run either with a licensed ... with IDL and is available from Exelis Visual Information Solutions . The IDL VM software can be downloaded from this site or ordered ...
Learning Routines in Innovation Processes
ERIC Educational Resources Information Center
Hoeve, Aimee; Nieuwenhuis, Loek F. M.
2006-01-01
Purpose: This paper aims to generate both a theoretical and an empirical basis for a research model that serves in further research as an analytical tool for understanding the complex phenomenon of learning at different levels in a work organisation. The key concept in this model is the routine concept of Nelson and Winter.…
NASA Astrophysics Data System (ADS)
Arts, T.; Lambertderouvroit, M.; Rutherford, A. W.
1990-09-01
An experimental aerothermal investigation of a highly loaded transonic turbine nozzle guide vane mounted in a linear cascade arrangement is presented. The measurements were performed in a short duration isentropic light piston compression tube facility, allowing a correct simulation of Mach and Reynolds numbers as well as of the gas to wall temperature ratio compared to the values currently observed in modern aeroengines. The experimental program consisted of the following: (1) flow periodicity checks by means of wall static pressure measurements and Schlieren flow visualizations; (2) blade velocity distribution measurements by means of static pressure tappings; (3) blade convective heat transfer measurements by means of static pressure tappings; (4) blade convective heat transfer measurements by means of platinium thin films; (5) downstream loss coefficient and exit flow angle determinations by using a new fast traversing mechanism; and (6) free stream turbulence intensity and spectrum measurements. These different measurements were performed for several combinations of the free stream flow parameters looking at the relative effects on the aerodynamic blade performance and blade convective heat transfer of Mach number, Reynolds number, and freestream turbulence intensity.
NASA Astrophysics Data System (ADS)
AMABILI, M.; PELLICANO, F.; PAÏDOUSSIS, M. P.
2000-11-01
The response of simply supported circular cylindrical shells to harmonic excitation in the spectral neighbourhood of one of the lowest natural frequencies is investigated by using improved mode expansions with respect to those assumed in Parts I and II of the present study. Two cases are studied: (1) shells in vacuo; and (2) shells filled with stagnant water. The improved expansions allow checking the accuracy of the solutions previously obtained and giving definitive results within the limits of Donnell's non-linear shallow-shell theory. The improved mode expansions include: (1) harmonics of the circumferential mode number n under consideration, and (2) only the principal n, but with harmonics of the longitudinal mode included. The effect of additional longitudinal modes is absolutely insignificant in both the driven and companion mode responses. The effect of modes with 2 n circumferential waves is very limited on the trend of non-linearity, but is significant in the response with companion mode participation in the case of lightly damped shells (empty shells). In particular, the travelling wave response appears for much lower vibration amplitudes and presents a frequency range without stable responses, corresponding to a beating phenomenon. A liquid (water) contained in the shell generates a much stronger softening behaviour of the system. Experiments with a water-filled circular cylindrical shell made of steel are in very good agreement with the present theory.
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.
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).
[Pharmacogenomics in routine medical care].
Rosskopf, D; Meyer zu Schwabedissen, H E; Kroemer, H K; Siegmund, W
2010-01-01
Pharmacogenomics investigates inherited differences in drug responses including beneficial and adverse reactions. While a considerable amount of evidence for genetic influences on drug responses has been accumulated within the last decade, predominantly in small studies, its value in routine therapy is still a matter of debate. The aim of this review is to discuss well established examples where pharmacogenomic techniques can improve routine treatment. Examples include genotyping of CYP2D6 in the context of antidepressant therapy, analysis of TPMT variants for the prediction of mercaptopurine-induced bone marrow depression, VKORC1 and CYP2C9 analyses for a better control of anticoagulant administration and the SLCO1B1 variant in the context of statin-induced myopathies. PMID:20101557
Memos trace routine radiation overexposures
Lobsenz, G.
1994-03-09
Workers at the Energy Department's Fernald plant routinely received [open quotes]gross,[close quotes] [open quotes]unacceptable[close quotes] and [open quotes]undue[close quotes] radiation exposures during uranium processing operations from the 1950s through the early 1970s, according to internal Fernald memos. The documents come to light as DOE continues to pay hundreds of thousands of dollars every month to defend its former Fernald contractor, NLO Inc., from a workers' lawsuit seeking compensation for alleged injuries from poor safety practices at the Ohio facility. DOE officials have contended the NLO defense effort is justified because there is no evidence that any former Fernald workers have suffered injury as a result of radiation exposures at the plant. However, the internal Fernald memos document major concerns expressed by Fernald health officials about unsafe working conditions at the plant and what appear in some cases to be routine overexposures of workers.
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.
Routine outcome measurement in Australia.
Burgess, Philip; Pirkis, Jane; Coombs, Tim
2015-08-01
Australia has been implementing routine outcome measurement in its specialized public sector mental health services for over a decade. It uses a range of clinician-rated and consumer-rated measures that are administered at set times during episodes of inpatient, ambulatory and community residential episodes of care. Routine outcome measurement is now embedded in service delivery, and data are made available in a variety of ways to different audiences. These data are used by policy-makers and planners to inform decisions about system-wide reforms, by service managers to monitor quality and effectiveness, and by clinicians to guide clinical decision-making and to promote dialogue with consumers. Consumers, carers and the general community can use these data to ensure that services are accountable for the care they deliver. This paper describes the status quo in Australia with respect to routine outcome measurement, discusses the factors that led to its successful implementation, and considers the steps that are necessary for its continued development. PMID:25768326
NASA Technical Reports Server (NTRS)
Hsu, Y. K.; Swanson, T.; Mcintosh, R.
1988-01-01
Future large space based facilities, such as Space Station, will require energy management systems capable of transporting tens of kilowatts of heat over a hundred meters or more. This represents better than an order of magnitude improvement over current technology. Two-phase thermal systems are currently being developed to meet this challenge. Condensation heat transfer plays a very important role in this system. The present study attempts an analytic solution to the set of linearized partial differential equations. The axial velocity and temperature functions were found to be Bessel functions which have oscillatory behavior. This result agrees qualitatively with the experimental evidence from tests at both NASA Goddard Space Flight Center and elsewhere.
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. PMID:25448535
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)
Seychelles, F.; Mergui, S.; Nicolas, X.
2012-11-01
A combined experimental and numerical study of a Rayleigh-Bénard-Poiseuille air flow in a rectangular channel is presented. The aim of the present paper is to characterize a secondary instability, referred to as wavy instability and known to be a convective instability, with the objective to identify the best situation for an optimal homogenization of heat transfers in the system. A periodic mechanical excitation is introduced at channel inlet and the spatial and temporal evolution of the temperature fluctuations are analyzed, depending on the Rayleigh number, the frequency and the amplitude of the perturbation. The Reynolds number is fixed. As the saturated state is a priori the best situation to homogenize the transfers, the objective is to expand the saturation area and to generate a maximum saturation amplitude value. It is shown that the best choice is a high Rayleigh number or/and a large magnitude of perturbation associated with a specific low value of the forcing frequency.
NASA Astrophysics Data System (ADS)
Wade, Patrick C.
Upstream propagating waves impinging on a cascade of compressor blades were examined in an effort to better understand the influence of downstream components on high cycle fatigue in turbine engines. An array of cylinders was used to simulate the unsteady field generated by a rotor downstream of a set of stators. The unsteady flow upstream of a single cylinder and an array of cylinders, with and without an upstream cascade, was examined experimentally and computationally. Computational results indicate that the cylinders would only shed coherently when placed downstream of a set of blades. Coherent shedding is created when each of the cylinders in the array shed a vortex at the same instant in time. The computational results were verified experimentally and the required flow conditions for coherent vortex shedding were examined. Coherent vortex shedding was maximized by placing the cylinders in the centerline of the blade passages. The unsteady velocity was measured over a cascade blade with the cylinders located in an array downstream of the blades. Unsteady velocities measured along the blade indicate that the downstream cylinders create upstream propagating velocity fluctuations that are maximum at the trailing edge. The increasing amplitude of the unsteady velocities towards the trailing edge of the blade was seen both experimentally and computationally. Additionally, the computational results show that the unsteady fluctuations in the pressure along the blade surface also increases towards the trailing edge of the blade. The magnitude of the upstream propagating velocity fluctuations was increased with increasing freestream velocity. Unsteady velocities generated by individual cylinders were superposed to recreate the unsteady flowfield of the cylinder array and compared favorably with the cylinder array results towards the trailing edge of the blade.
Doughty, C.; Pruess, K.
1991-03-01
A semianalytical solution for transient two-phase water, air, and heat flow in a uniform porous medium surrounding a constant-strength linear heat source has been developed, using a similarity variable {eta}=r/{radical}t (r is radial distance, t is time). Although the similarity transformation requires a simplified radial geometry, all the physical mechanisms involved in two-phase fluid and heat flow may be taken into account in a rigorous way. The solution includes nonlinear thermophysical fluid and material properties, such as relative permeability and capillary pressure variations with saturation, and density and viscosity variations with temperature and pressure. The resulting governing equations form a set of coupled nonlinear ODEs, necessitating numerical integration. The solution has been applied to a partially saturated porous medium initially at a temperature well below the saturation temperature, which is the setting for the potential nuclear waste repository site at Yucca Mountain, Nevada. The resulting heat and fluid flows provide a stringent test of many of the capabilities of numerical simulation models, making the similarity solution a useful tool for model verification. Comparisons to date have shown excellent agreement between the TOUGH2 simulator and the similarity solution for a variety of conditions. 13 refs., 6 figs., 1 tab.
Global routine vaccination coverage, 2009.
2010-10-29
The widespread use of vaccines has greatly improved global public health, preventing millions of childhood hospitalizations and deaths each year. Vaccination of children also is projected to avert adult deaths through the prevention of hepatitis B (HepB) virus--related chronic liver disease and liver cancer and human papilloma virus--related cervical cancer. When the World Health Organization (WHO) began the Expanded Programme on Immunization in 1974, <5% of the world's children had been fully vaccinated with bacille Calmette-Guérin (BCG), diphtheria-tetanus-pertussis (DTP) vaccine, oral poliovirus vaccine, and measles-containing vaccine (MCV) during the first year of life. Since then, increased vaccination coverage has resulted in substantial reductions in morbidity and mortality, including a >99% decline in polio incidence since 1988, with eradication on the horizon, and a 78% decline in measles-associated mortality from 2000 to 2008 With the introduction of Haemophilus influenzae type b (Hib) vaccine, HepB vaccine, pneumococcal conjugate vaccine (PCV), and rotavirus vaccine into many countries' routine vaccination schedules, further reductions in morbidity and mortality are expected. However, based on an annual global birth cohort of approximately 130 million, an estimated 23 million infants worldwide still do not receive the benefits of routine vaccination (i.e., 3 doses of DTP during the first year of life). The Global Immunization Vision and Strategy (GIVS), developed in 2005 by WHO and UNICEF, assists countries in strengthening immunization programs and vaccinating more persons. GIVS aims to achieve 90% national 3-dose DTP (DTP3) coverage by age 12 months in all countries, and 80% coverage in every district or equivalent administrative unit by 2010 (and to sustain these levels through 2015). This report summarizes global routine vaccination coverage during 2000--2009 and progress toward achieving GIVS goals. PMID:21030941
Routine activities and victimization at school: the significance of gender.
Popp, Ann Marie; Peguero, Anthony A
2011-08-01
Routine activities theory has not fully considered the role of gender in shaping victimization and yet, the research literature clearly demonstrates that gender is associated with an individual's risk of victimization. In addition to the pervasive effect of gender on victimization, gender shapes an individual's daily routines and thus may create a gender-specific relationship with victimization. This article explores the importance of gender in understanding the relationship between student's participation in extracurricular routine activities (e.g., student government, clubs, sports, and etc.) and the risk of victimization. From the Education Longitudinal Study of 2002, a sample of 10th-grade students was drawn for analyses. Hierarchical Generalized Linear Modeling was employed to explore the role of gender in the relationship between extracurricular routine activities and victimization at school. The results reveal that students' gender indeed interacts with several of the extracurricular routine activities creating gender-specific risks of victimization. This article highlights the importance of gender in explaining victimization and suggests researchers should consider how gender may interact with other routine activities and victimization. PMID:20956442
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.
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
VII: VME/IORFI-II interface routines
Alleva, D.
1988-07-07
This document describes the VME/IORFI-II Interface routines (VII). These routines where designed to meet two needs. First, the routines enable programs written in PILS running on a MVME 101 under Valet-Plus to control an IORFI-II interface from VME. Secondly, the routines provide a high level language version of the FASTBUS standard routines for the IORFI-II which can easily be translated into other high level languages (like C). The routines fall into two general types, control and transaction. The control routines work directly with the interface registers. These routines set up and monitor operations between VME and the IORFI-II. The control routines are usually used indirectly by the programmer through the transaction routines. The transaction routines, such as VIIreverse arrowWRITEreverse arrowDAT, use the control routines to carry out complete functions on FASTBUS. Most FASTBUS operations have been implemented except for the compound routines and some low level routines. To facilitate access to the IORFI-II registers from VME, a Super-VIOR DMA board was used as a set of I/O registers tied to the IORFI-II's front panel connectors. The DMA controller on the Super-VIOR was not used and a much simpler board (only containing a set of four registers accessible from VME) could replace the Super-VIOR. The routines are written in PILS, a high-level language similar to BASIC and Pascal which is powerful and fast enough for most applications. However, PILS has proven to be too slow for efficient control of the IORFI-II. This is discussed further in this paper along with a discussion of possible future implementations of the routines.
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, 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, 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, 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...
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, 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...
DeMuth, S.F.; Watson, J.S.
1985-01-01
A model of compressible flow through an orifice, in the region of transition from free molecular to isentropic expansion flow, has been developed and tested for accuracy. The transitional or slip regime is defined as the conditions where molecular interactions are too many for free molecular flow modeling, yet not great enough for isentropic expansion flow modeling. Due to a lack of literature establishing a well-accepted model for predicting transitional flow, it was felt such work would be beneficial. The model is nonlinear and cannot be satisfactorily linearized for a linear regression analysis. Consequently, a computer routine was developed which minimized the sum of the squares of the residual flow for the nonlinear model. The results indicate an average accuracy within 15% of the measured flow throughout the range of test conditions. Furthermore, the results of the regression analysis indicate that the transitional regime lies between Knudsen numbers of approximately 2 and 45. 4 refs., 3 figs., 1 tab.
Routine outcome measures in Canada.
Kisely, Steve; Adair, Carol E; Lin, Elizabeth; Marriott, Brian
2015-01-01
Canada is a federal country of 10 provinces and three territories. High level information on mental health conditions and service use has mostly been generated from administrative data collected by provinces and territories. These include four major types - hospital admissions and discharges, physician billings, ambulatory care services, and drug databases. At the national level, the Canadian Institute for Health Information brings together this information to produce indicators of outcome. Although these data provide information on patient and health system characteristics, they do not capture the full spectrum of formal and informal mental healthcare. These include changes in health status, functioning, community integration and quality of life. As a result, some jurisdictions have begun to implement more standardized measures of outcome such as the clinician-rated Health of the Nation Outcome Scales or the inpatient Resident Assessment Instrument - Mental Health. In this paper we provide an overview of mental-health-related data sources in Canada, highlight some of the more progressive practices beginning to emerge, and conclude with some thoughts about how the routine measurement and reporting of mental health outcomes in Canada might be advanced including efforts at engaging both clinicians and decision-makers. PMID:25738745
Routine fetal genitourinary tract screening.
Arger, P H; Coleman, B G; Mintz, M C; Snyder, H P; Camardese, T; Arenson, R L; Gabbe, S G; Aquino, L
1985-08-01
To evaluate routine fetal genitourinary tract obstetrical ultrasound screening, and to determine what size renal pelvis is indicative of significant renal disease, we reviewed 4,832 examinations, which had been performed over 2 years, of 3,530 consecutive obstetrical patients. Any fetus that had a renal pelvis greater than 5 mm or a definable cystic area was identified for follow-up. The fetuses of 39 patients (1.1%) who underwent 112 examinations fulfilled these criteria and constitute the basis of this report. A variety of examination criteria were recorded and analyzed in relationship to the follow-up, which ranged from 2-3 days to 21 months. The fetuses of the 39 patients were grouped into three categories: those with renal pelves between 5 and 9 mm in size; those with renal pelves larger than 10 mm; and those with cystic abnormalities. Those with renal pelves larger than 10 mm had either an obstructing lesion or exceptional extrarenal pelves. The clinical and pathologic aspects of these three groups are detailed, discussed, and analyzed. Criteria for significant fetal renal hydronephrosis and aspects of a loculated appearance are given. PMID:3892578
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.
Parental employment, family routines and childhood obesity.
Anderson, Patricia M
2012-12-01
Using the Early Childhood Longitudinal Survey-Kindergarten Class of 1998-1999 (ECLS-K) data from kindergarten through eighth grade, this paper investigate the relationships among maternal employment, family routines and obesity. More hours worked by the mother tend to be negatively related to positive routines like eating meals as a family or at regular times, or having family rules about hours of television watched. Many of these same routines are significantly related to the probability of being obese, implying that family routines may be a mechanism by which maternal employment intensity affects children's obesity. However, inclusion of family routines in the obesity regression does not appreciably change the estimated effect of maternal employment hours. Thus, the commonly estimated deleterious effect of maternal employment on children's obesity cannot be explained by family routines, leaving the exact mechanisms an open question for further exploration. PMID:22622096
NASA Technical Reports Server (NTRS)
Hess, J. L.; Martin, R. P., Jr.
1974-01-01
The surface-source method of calculating potential flow is improved by refining the underlying numerical analysis. The analysis uses parabolic elements and linearly-varying source density. The result is a large increase in computing speed and accuracy. The theory is described, and the effectiveness of the modification is illustrated.
Immunophenotyping of Posttraumatic Neutrophils on a Routine Haematology Analyser
Groeneveld, Kathelijne Maaike; Heeres, Marjolein; Leenen, Loek Petrus Hendrikus; Huisman, Albert; Koenderman, Leo
2012-01-01
Introduction. Flow cytometry markers have been proposed as useful predictors for the occurrence of posttraumatic inflammatory complications. However, currently the need for a dedicated laboratory and the labour-intensive analytical procedures make these markers less suitable for clinical practice. We tested an approach to overcome these limitations. Material and Methods. Neutrophils of healthy donors were incubated with antibodies commonly used in trauma research: CD11b (MAC-1), L-selectin (CD62L), FcγRIII (CD16), and FcγRII (CD32) in active form (MoPhab A27). Flow cytometric analysis was performed both on a FACSCalibur, a standard flow cytometer, and on a Cell-Dyn Sapphire, a routine haematology analyser. Results. There was a high level of agreement between the two types of analysers, with 41% for FcγRIII, 80% for L-selectin, 98% for CD11b, and even a 100% agreement for active FcγRII. Moreover, analysis on the routine haematology analyser was possible in less than a quarter of the time in comparison to the flow cytometer. Conclusion. Analysis of neutrophil phenotype on the Cell-Dyn Sapphire leads to the same conclusion compared to a standard flow cytometer. The markedly reduced time necessary for analysis and reduced labour intensity constitutes a step forward in implementation of this type of analysis in clinical diagnostics in trauma research. PMID:22523451
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
Dele-Michael, Abiola O.; Fujikura, Kana; Devereux, Richard B; Islam, Fahmida; Hriljac, Ingrid; Wilson, Sean R.; Lin, Fay; Weinsaft, Jonathan W.
2014-01-01
Background Echocardiography (echo) quantified LV stroke volume (SV) is widely used to assess systolic performance after acute myocardial infarction (AMI). This study compared two common echo approaches – predicated on flow (Doppler) and linear chamber dimensions (Teichholz) – to volumetric SV and global infarct parameters quantified by cardiac magnetic resonance (CMR). Methods Multimodality imaging was performed as part of a post-AMI registry. For echo, SV was measured by Doppler and Teichholz methods. Cine-CMR was used for volumetric SV and LVEF quantification, and delayed-enhancement CMR for infarct size. Results 142 patients underwent same-day echo and CMR. On echo, mean SV by Teichholz (78±17ml) was slightly higher than Doppler (75±16ml; Δ=3±13ml, p=0.02). Compared to SV on CMR (78±18ml), mean difference by Teichholz (Δ=−0.2±14; p=0.89) was slightly smaller than Doppler (Δ−3±14; p=0.02) but limits of agreement were similar between CMR and echo methods (Teichholz: −28, 27 ml, Doppler: −31, 24ml). For Teichholz, differences with CMR SV were greatest among patients with anteroseptal or lateral wall hypokinesis (p<0.05). For Doppler, differences were associated with aortic valve abnormalities or root dilation (p=0.01). SV by both echo methods decreased stepwise in relation to global LV injury as assessed by CMR-quantified LVEF and infarct size (p<0.01). Conclusions Teichholz and Doppler calculated SV yield similar magnitude of agreement with CMR. Teichholz differences with CMR increase with septal or lateral wall contractile dysfunction, whereas Doppler yields increased offsets in patients with aortic remodeling. PMID:23488864
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
10 CFR 1017.20 - Routine access.
Code of Federal Regulations, 2011 CFR
2011-01-01
... INFORMATION Access to Unclassified Controlled Nuclear Information § 1017.20 Routine access. (a) Authorized... 10 Energy 4 2011-01-01 2011-01-01 false Routine access. 1017.20 Section 1017.20 Energy DEPARTMENT... access to the UCNI, subject to limitations in paragraph (b) of this section, and who may...
10 CFR 1017.20 - Routine access.
Code of Federal Regulations, 2010 CFR
2010-01-01
... INFORMATION Access to Unclassified Controlled Nuclear Information § 1017.20 Routine access. (a) Authorized... 10 Energy 4 2010-01-01 2010-01-01 false Routine access. 1017.20 Section 1017.20 Energy DEPARTMENT... access to the UCNI, subject to limitations in paragraph (b) of this section, and who may...
Achieving Communicative Competence Through Gambits and Routines.
ERIC Educational Resources Information Center
Siskin, H. Jay; Spinelli, Emily
1987-01-01
Analyzes the importance of conversational gambits and routines in achieving second language communicative competence and then presents a model which uses telephone conversations as a means of achieving this goal. Exercises for drilling and testing gambits and routines are also presented. (Author/CB)
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 (CONTINUED) NATIONAL PRIMARY DRINKING WATER REGULATIONS Stage 2 Disinfection Byproducts Requirements § 141.621 Routine monitoring. (a) Monitoring. (1) If...
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…
Metadata Extraction Routines for Improving Infobutton Performance
Hulse, Nathan C.; Haug, Peter J.
2010-01-01
Infobuttons have been proven as an effective means for providing quick, context-specific links to pertinent information resources at the point of care. Current infobutton manager implementations, however, lack the ability to exchange metadata, are limited to a relatively small set of information providers, and are targeted primarily for a clinician audience. As part of a local effort to implement infobuttons for patient use via a tethered personal health record, we present a series of metadata extraction routines. These routines were constructed to extract key pieces of information from health information providers on the Internet, including content coverage, language availability, and readability scores. The extraction routines were tested using thirty different disease conditions against eight different providers. The routines yielded 183 potential infobutton targets and associated metadata for each. The capabilities of the extraction routines will be expanded to cover new types of metadata in the future. PMID:21346994
NASA Astrophysics Data System (ADS)
Sidorin, Anatoly
2010-01-01
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.
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.
Improving discharge estimates from routine river flow monitoring in Sweden
NASA Astrophysics Data System (ADS)
Capell, Rene; Arheimer, Berit
2016-04-01
The Swedish Meteorological and Hydrological Institute (SMHI) maintains a permanent river gauging network for national hydrological monitoring which includes 263 gauging stations in Sweden. At all these stations, water levels are measured continuously, and discharges are computed through rating curves. The network represents a wide range of environmental settings, different gauging measurement types and gauging frequencies. Gauging frequencies are typically low compared with river gauges in more research-oriented settings, and thus uncertainties in discharges, particularly extremes, can be large. On the other hand, the gauging stations have often been in use for very long, with the oldest measurements dating back to 1900, and at least partly exhibit very stable conditions. Here, we show the variation in gauging stability in the SMHI's gauging network in order to try to identify more error-prone conditions. We investigate how the current, largely subjective, way of updating rating curves influences discharge estimates, and discuss ways forward towards a more objective evaluation of both discharge uncertainty and rating curve updating procedures.
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…
Bull, Leah E; Oliver, Chris; Callaghan, Eleanor; Woodcock, Kate A
2015-06-01
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 that routine. Play based challenges exposed 16 participants to routines, which were either adhered to or changed. Temper outburst behaviors, heart rate and movement were measured. As participants were exposed to routines for longer before a change (between 10 and 80 min; within participants), more temper outburst behaviors were elicited by changes. Increased emotional arousal was also elicited, which was indexed by heart rate increases not driven by movement. Further study will be important to understand whether current intervention approaches that limit exposure to changes, may benefit from the structured integration of flexibility to ensure that the opportunity for routine establishment is also limited. PMID:25422033
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.
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, ...
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)
Simplified Linear Equation Solvers users manual
Gropp, W. ); Smith, B. )
1993-02-01
The solution of large sparse systems of linear equations is at the heart of many algorithms in scientific computing. The SLES package is a set of easy-to-use yet powerful and extensible routines for solving large sparse linear systems. The design of the package allows new techniques to be used in existing applications without any source code changes in the applications.
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.
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.
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.
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.
Celestial: Common astronomical conversion routines and functions
NASA Astrophysics Data System (ADS)
Robotham, Aaron S. G.
2016-02-01
The R package Celestial contains common astronomy conversion routines, particularly the HMS and degrees schemes, and a large range of functions for calculating properties of different cosmologies (as used by the cosmocalc website). This includes distances, ages, growth rate/factor and densities (e.g., Omega evolution and critical energy density). It also includes functions for calculating thermal properties of the CMB and Planck's equations and virial properties of halos in different cosmologies, and standard NFW and weak-lensing formulas and low level orbital routines for calculating Roche properties, Vis-Viva and free-fall times.
ANSYS duplicate finite-element checker routine
NASA Technical Reports Server (NTRS)
Ortega, R.
1995-01-01
An ANSYS finite-element code routine to check for duplicated elements within the volume of a three-dimensional (3D) finite-element mesh was developed. The routine developed is used for checking floating elements within a mesh, identically duplicated elements, and intersecting elements with a common face. A space shuttle main engine alternate turbopump development high pressure oxidizer turbopump finite-element model check using the developed subroutine is discussed. Finally, recommendations are provided for duplicate element checking of 3D finite-element models.
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.
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
Antiretroviral drug resistance and routine therapy, Cameroon.
Laurent, Christian; Kouanfack, Charles; Vergne, Laurence; Tardy, Michèle; Zekeng, Léopold; Noumsi, Nathalie; Butel, Christelle; Bourgeois, Anke; Mpoudi-Ngolé, Eitel; Koulla-Shiro, Sinata; Peeters, Martine; Delaporte, Eric
2006-06-01
Among 128 patients routinely receiving highly active antiretroviral therapy in an HIV/AIDS outpatient clinic in Cameroon, 16.4% had drug resistance after a median of 10 months. Of these, 12.5% had resistance to nucleoside reverse transcriptase inhibitors (NRTIs), 10.2% to non-NRTIs, and 2.3% to protease inhibitors. PMID:16707062
7 CFR 4287.107 - Routine servicing.
Code of Federal Regulations, 2012 CFR
2012-01-01
... RURAL UTILITIES SERVICE, DEPARTMENT OF AGRICULTURE SERVICING Servicing Business and Industry Guaranteed... the December 31 semiannual status report in accordance with 7 CFR part 4279, subpart B, § 4279.107. (b... 7 Agriculture 15 2012-01-01 2012-01-01 false Routine servicing. 4287.107 Section...
7 CFR 4287.107 - Routine servicing.
Code of Federal Regulations, 2013 CFR
2013-01-01
... RURAL UTILITIES SERVICE, DEPARTMENT OF AGRICULTURE SERVICING Servicing Business and Industry Guaranteed... the December 31 semiannual status report in accordance with 7 CFR part 4279, subpart B, § 4279.107. (b... 7 Agriculture 15 2013-01-01 2013-01-01 false Routine servicing. 4287.107 Section...
7 CFR 4287.107 - Routine servicing.
Code of Federal Regulations, 2014 CFR
2014-01-01
... RURAL UTILITIES SERVICE, DEPARTMENT OF AGRICULTURE SERVICING Servicing Business and Industry Guaranteed... the December 31 semiannual status report in accordance with 7 CFR part 4279, subpart B, § 4279.107. (b... 7 Agriculture 15 2014-01-01 2014-01-01 false Routine servicing. 4287.107 Section...
7 CFR 4287.107 - Routine servicing.
Code of Federal Regulations, 2011 CFR
2011-01-01
... RURAL UTILITIES SERVICE, DEPARTMENT OF AGRICULTURE SERVICING Servicing Business and Industry Guaranteed... the December 31 semiannual status report in accordance with 7 CFR part 4279, subpart B, § 4279.107. (b... 7 Agriculture 15 2011-01-01 2011-01-01 false Routine servicing. 4287.107 Section...
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…
Routine Markerless Gene Replacement in Bacillus anthracis
Janes, Brian K.; Stibitz, Scott
2006-01-01
An improved genetic tool suitable for routine markerless allelic exchange in Bacillus anthracis has been constructed. Its utility was demonstrated by the introduction of insertions, deletions, and missense mutations on the chromosome and plasmid pXO1 of the Sterne strain of B. anthracis. PMID:16495572
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…
Workout to Go: A Sample Exercise Routine
Workout to Go A Sample Exercise Routine from the National Institute on Aging at NIH i Workout to Go Are you just starting to exercise? Getting back ... into your purse or travel bag, Workout to Go can help you stay in shape for the ...
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…
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
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
Mattar, L.; Adegbesan, L.O.
1980-01-01
The differential equation for flow of gases in a porous medium is nonlinear and cannot be solved by strictly analytical methods. Previous studies in the literature have obtained analytical solutions to this equation by linearlization (i.e., treating viscosity and compressibilty as constant). In this study, the solution for nonlinear gas flow equation is obtained using the semianalytical technique developed by Kale and Mattar which solves the nonlinear equation by the method of perturbation. Results obtained, for prediction of pressure drawdown in gas reservoirs, indicate that the solution of the linearlized form of the equation is valid for both low and high permeability reservoirs.
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.
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
Preconditioned quantum linear system algorithm.
Clader, B D; Jacobs, B C; Sprouse, C R
2013-06-21
We describe a quantum algorithm that generalizes the quantum linear system algorithm [Harrow et al., Phys. Rev. Lett. 103, 150502 (2009)] to arbitrary problem specifications. We develop a state preparation routine that can initialize generic states, show how simple ancilla measurements can be used to calculate many quantities of interest, and integrate a quantum-compatible preconditioner that greatly expands the number of problems that can achieve exponential speedup over classical linear systems solvers. To demonstrate the algorithm's applicability, we show how it can be used to compute the electromagnetic scattering cross section of an arbitrary target exponentially faster than the best classical algorithm. PMID:23829722
On the stability of numerical integration routines for ordinary differential equations.
NASA Technical Reports Server (NTRS)
Glover, K.; Willems, J. C.
1973-01-01
Numerical integration methods for the solution of initial value problems for ordinary vector differential equations may be modelled as discrete time feedback systems. The stability criteria discovered in modern control theory are applied to these systems and criteria involving the routine, the step size and the differential equation are derived. Linear multistep, Runge-Kutta, and predictor-corrector methods are all investigated.
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.
NASA Astrophysics Data System (ADS)
Adcock, T. A. A.; Taylor, P. H.
2016-01-01
The non-linear Schrödinger equation and its higher order extensions are routinely used for analysis of extreme ocean waves. This paper compares the evolution of individual wave-packets modelled using non-linear Schrödinger type equations with packets modelled using fully non-linear potential flow models. The modified non-linear Schrödinger Equation accurately models the relatively large scale non-linear changes to the shape of wave-groups, with a dramatic contraction of the group along the mean propagation direction and a corresponding extension of the width of the wave-crests. In addition, as extreme wave form, there is a local non-linear contraction of the wave-group around the crest which leads to a localised broadening of the wave spectrum which the bandwidth limited non-linear Schrödinger Equations struggle to capture. This limitation occurs for waves of moderate steepness and a narrow underlying spectrum.
Energy Science and Technology Software Center (ESTSC)
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
The place of routine HIV testing.
2011-08-01
In 2009, around 86,500 people in the UK had HIV infection, of whom around a quarter were unaware of their condition. Of adults diagnosed in that year, around half were already at a late stage of disease (with a CD4 count below 350 cells/μL or presenting with an AIDS-defining event). Such late diagnosis represents a missed opportunity for treatment and prevention, and is associated with significant morbidity and mortality, reduced response to antiretroviral drugs and increased healthcare costs. In genitourinary medicine (GUM) clinics and during antenatal care, there is a high uptake rate of routine testing (i.e. HIV tests are offered as part of standard care and the individual has the option to decline). Increasing such testing across other healthcare settings could reduce late diagnosis. Here we examine issues around routine HIV testing. PMID:21813559
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.
PROFIT: Emission-line PROfile FITting routine
NASA Astrophysics Data System (ADS)
Riffel, Rogemar A.
2012-04-01
The PROFIT is an IDL routine to do automated fitting of emission-line profiles by Gaussian curves or Gauss-Hermite series otimized for use in Integral Field and Fabry-Perot data cubes. As output PROFIT gives two-dimensional FITS files for the emission-line flux distribution, centroid velocity, velocity dispersion and higher order Gauss-Hermite moments (h3 and h4).
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
Is routine use of episiotomy justified?
Lede, R L; Belizán, J M; Carroli, G
1996-05-01
Episiotomy, one of the most common surgical procedures, was introduced in clinical practice in the eighteenth century without having strong scientific evidence of its benefits. Its use was justified by the prevention of severe perineal tears, better future sexual function, and a reduction of urine and fecal incontinence. With regard to the first assumption, the evidence that is based on five randomized controlled trials shows a 9% reduction in severe perineal tears in the selective use of episiotomy, but this effect fluctuates between a 40% reduction and a 38% increase. In relation to long-term effects, women in whom management includes routine use of episiotomy have shown poorer future sexual function, similar pelvic floor muscle strength, and similar urinary incontinence in comparison with women in whom episiotomy is used in a selective manner. In summary, there is no reliable evidence that routine use of episiotomy has any beneficial effect; on the contrary, there is clear evidence that it may cause harm such as a greater need for surgical repair and a poorer future sexual capability. In view of the available evidence the routine use of episiotomy should be abandoned and episiotomy rates > 30% do not seem justified. PMID:9065102
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. PMID:26371731
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.
Parent routines for managing cystic fibrosis in children.
Grossoehme, Daniel H; Filigno, Stephanie Spear; Bishop, Meredith
2014-06-01
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
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.
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.
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
The Phantom Urine: An Unexpected Finding during a Routine Cesarean Section
Achtari, Chahin; Meuwly, Jean-Yves
2014-01-01
We present here an atypical finding during an elective repeat cesarean section. Despite urine flow through an indwelling bladder catheter, bladder remains distended during the whole procedure. Unexpected anatomical variations and malformations can make routine surgery challenging. Urinary tract anomalies should be suspected in cases of unexpected difficult bladder catheterization. PMID:24707418
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.
Probabilistic earthquake location and 3-D velocity models in routine earthquake location
NASA Astrophysics Data System (ADS)
Lomax, A.; Husen, S.
2003-12-01
Earthquake monitoring agencies, such as local networks or CTBTO, are faced with the dilemma of providing routine earthquake locations in near real-time with high precision and meaningful uncertainty information. Traditionally, routine earthquake locations are obtained from linearized inversion using layered seismic velocity models. This approach is fast and simple. However, uncertainties derived from a linear approximation to a set of non-linear equations can be imprecise, unreliable, or even misleading. In addition, 1-D velocity models are a poor approximation to real Earth structure in tectonically complex regions. In this paper, we discuss the routine location of earthquakes in near real-time with high precision using non-linear, probabilistic location methods and 3-D velocity models. The combination of non-linear, global search algorithms with probabilistic earthquake location provides a fast and reliable tool for earthquake location that can be used with any kind of velocity model. The probabilistic solution to the earthquake location includes a complete description of location uncertainties, which may be irregular and multimodal. We present applications of this approach to determine seismicity in Switzerland and in Yellowstone National Park, WY. Comparing our earthquake locations to earthquake locations obtained using linearized inversion and 1-D velocity models clearly demonstrates the advantages of probabilistic earthquake location and 3-D velocity models. For example, the more complete and reliable uncertainty information of non-linear, probabilistic earthquake location greatly facilitates the identification of poorly constrained hypocenters. Such events are often not identified in linearized earthquake location, since the location uncertainties are determined with a simplified, localized and approximate Gaussian statistic.
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.
York, T.M.; Klevans, E.H.
1980-05-01
Experimental and analytical studies of particle and energy loss at the ends of a linear theta pinch have been carried out. A study of transients occurring in the formation of reversed trapped fields within the coil, and of transients in the end region of a 25 cm long device was completed. A 1-D code has proven to be highly accurate in describing loss events and defining transport mechanisms in different experiments and is described here. A study of loss along field lines in a 50 cm long device has generated new information on loss velocity, axial and radial temperature gradients, and has established an initial effort in understanding thermal loss to the walls. Rotation and parallel trapped fields have been added to the existing 0-D code. A new technique crowbar switch and magnetic field prediction code have been developed. Direct measurment of electron velocity with Thomson scattering was accomplished experimentally. A Nd-glass laser system, frequency doubled, is being developed for low density diagnostics. Theoretical results that accurately predict confinement in FRX devices are described.
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.
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.
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
PC Basic Linear Algebra Subroutines
Energy Science and Technology Software Center (ESTSC)
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
Meel-van den Abeelen, Aisha S S; Simpson, David M; Wang, Lotte J Y; Slump, Cornelis H; Zhang, Rong; Tarumi, Takashi; Rickards, Caroline A; Payne, Stephen; Mitsis, Georgios D; Kostoglou, Kyriaki; Marmarelis, Vasilis; Shin, Dae; Tzeng, Yu-Chieh; Ainslie, Philip N; Gommer, Erik; Müller, Martin; Dorado, Alexander C; Smielewski, Peter; Yelicich, Bernardo; Puppo, Corina; Liu, Xiuyun; Czosnyka, Marek; Wang, Cheng-Yen; Novak, Vera; Panerai, Ronney B; Claassen, Jurgen A H R
2014-05-01
Transfer function analysis (TFA) is a frequently used method to assess dynamic cerebral autoregulation (CA) using spontaneous oscillations in blood pressure (BP) and cerebral blood flow velocity (CBFV). However, controversies and variations exist in how research groups utilise TFA, causing high variability in interpretation. The objective of this study was to evaluate between-centre variability in TFA outcome metrics. 15 centres analysed the same 70 BP and CBFV datasets from healthy subjects (n=50 rest; n=20 during hypercapnia); 10 additional datasets were computer-generated. Each centre used their in-house TFA methods; however, certain parameters were specified to reduce a priori between-centre variability. Hypercapnia was used to assess discriminatory performance and synthetic data to evaluate effects of parameter settings. Results were analysed using the Mann-Whitney test and logistic regression. A large non-homogeneous variation was found in TFA outcome metrics between the centres. Logistic regression demonstrated that 11 centres were able to distinguish between normal and impaired CA with an AUC>0.85. Further analysis identified TFA settings that are associated with large variation in outcome measures. These results indicate the need for standardisation of TFA settings in order to reduce between-centre variability and to allow accurate comparison between studies. Suggestions on optimal signal processing methods are proposed. PMID:24725709
Cost-utility of routine cataract surgery
Räsänen, Pirjo; Krootila, Kari; Sintonen, Harri; Leivo, Tiina; Koivisto, Anna-Maija; Ryynänen, Olli-Pekka; Blom, Marja; Roine, Risto P
2006-01-01
Background If decisions on health care spending are to be as rational and objective as possible, knowledge on cost-effectiveness of routine care is essential. Our aim, therefore, was to evaluate the cost-utility of routine cataract surgery in a real-world setting. Methods Prospective assessment of health-related quality of life (HRQoL) of patients undergoing cataract surgery. 219 patients (mean (SD) age 71 (11) years) entering cataract surgery (in 87 only first eye operated, in 73 both eyes operated, in 59 first eye had been operated earlier) filled in the 15D HRQoL questionnaire before and six months after operation. Direct hospital costs were obtained from a clinical patient administration database and cost-utility analysis performed from the perspective of the secondary care provider extrapolating benefits of surgery to the remaining statistical life-expectancy of the patients. Results Mean (SD) utility score (on a 0–1 scale) increased statistically insignificantly from 0.82 (0.13) to 0.83 (0.14). Of the 15 dimensions of the HRQoL instrument, only seeing improved significantly after operation. Mean utility score improved statistically significantly only in patients reporting significant or major preoperative seeing problems. Of the subgroups, only those whose both eyes were operated during follow-up showed a statistically significant (p < 0.001) improvement. Cost per quality-adjusted life year (QALY) gained was €5128 for patients whose both eyes were operated and €8212 for patients with only one eye operated during the 6-month follow-up. In patients whose first eye had been operated earlier mean HRQoL deteriorated after surgery precluding the establishment of the cost per QALY. Conclusion Mean utility gain after routine cataract surgery in a real-world setting was relatively small and confined mostly to patients whose both eyes were operated. The cost of cataract surgery per quality-adjusted life year gained was much higher than previously reported and
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.
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)
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.
Nonlinear periodization maximizes strength gains in split resistance training routines.
Monteiro, Artur G; Aoki, Marcelo S; Evangelista, Alexandre L; Alveno, Daniel A; Monteiro, Gizele A; Piçarro, Ivan da Cruz; Ugrinowitsch, Carlos
2009-07-01
The purpose of our study was to compare strength gains after 12 weeks of nonperiodized (NP), linear periodized (LP), and nonlinear periodized (NLP) resistance training models using split training routines. Twenty-seven strength-trained men were recruited and randomly assigned to one of 3 balanced groups: NP, LP, and NLP. Strength gains in the leg press and in the bench press exercises were assessed. There were no differences between the training groups in the exercise pre-tests (p > 0.05) (i.e., bench press and leg press). The NLP group was the only group to significantly increase maximum strength in the bench press throughout the 12-week training period. In this group, upper-body strength increased significantly from pre-training to 4 weeks (p < 0.0001), from 4 to 8 weeks (p = 0.004), and from 8 weeks to the post-training (p < 0.02). The NLP group also exhibited an increase in leg press 1 repetition maximum at each time point (pre-training to 4 weeks, 4-8 week, and 8 weeks to post-training, p < 0.0001). The LP group demonstrated strength increases only after the eight training week (p = 0.02). There were no further strength increases from the 8-week to the post-training test. The NP group showed no strength increments after the 12-week training period. No differences were observed in the anthropometric profiles among the training models. In summary, our data suggest that NLP was more effective in increasing both upper- and lower-body strength for trained subjects using split routines. PMID:19528843
Routine dyspnea assessment on unit admission.
Baker, Kathy; Barsamian, Jennifer; Leone, Danielle; Donovan, Barbara C; Williams, Donna; Carnevale, Kerry; Lansing, Robert; Banzett, Robert
2013-11-01
Dyspnea assessment is valuable in diagnosis, prognosis, symptom management, and targeted intervention, and in the allotment and management of patient care resources. The assessment of dyspnea, like that of pain, depends on patient self-report. Expert consensus panels have called for dyspnea to be measured quantitatively and documented on a routine basis, as is the practice with pain. But little information is available on how to measure and record dyspnea ratings systematically. Consequently, the prevalence of dyspnea in hospital settings may be greater than is generally recognized, and dyspnea may be insufficiently managed. This article describes a pilot study that sought to test the feasibility of measuring dyspnea as part of the initial patient assessment performed by nurses within several inpatient units of a large urban hospital. PMID:24113531
Recommendations on routine screening pelvic examination
Tonelli, Marcello; Gorber, Sarah Connor; Moore, Ainsley; Thombs, Brett D.
2016-01-01
Abstract Objective To review the 2014 American College of Physicians (ACP) guideline on the use of pelvic examinations to screen for cancer (other than cervical), pelvic inflammatory disease, or other benign gynecologic conditions to determine whether the ACP guideline on routine pelvic examinations was consistent with Canadian Task Force on Preventive Health Care (CTFPHC) standards and could be adapted or adopted. Methods The SNAP-IT (Smooth National Adaptation and Presentation of Guidelines to Improve Thrombosis Treatment) method was used to determine whether the ACP guideline was consistent with CTFPHC standards and could be adapted or adopted. Recommendations The CTFPHC recommends not performing a screening pelvic examination to screen for noncervical cancer, pelvic inflammatory disease, or other gynecological conditions in asymptomatic women. This is a strong recommendation with moderate-quality evidence. Conclusion The CTFPHC adopts the recommendation on screening pelvic examination as published by the ACP in 2014. PMID:26975912
[Routine hematologic parameters for thalassemia screening].
Schubert, S; Christofi, Y; Papadatou, A
1990-01-01
There is an evaluation of routine examination of the blood film for the recognition of Thalassaemia (Th.). The results of 100 blood films from each group--Th. major, Th. minor, healthy persons (centre for Thalassaemia "Bishop Makarios"/Nikosia--Cypros)-were analyzed. MCV and MCH were most useful for the recognition of Th. minor. The constellation of increased red blood cells and normal hemoglobin seems to be typical for Th. minor. Haemoglobin and haematocrit are not suited because they were widely normal. Target cells also are not sufficient for screening--they were present only in 10% of Th. minor. To the contrary most values were clearly decreased in Th. major, and target cells were present here in almost 90%. PMID:1713894
The routinization of hospice: charisma and bureaucratization.
James, N; Field, D
1992-06-01
In 25 years the number of hospices in Britain has multiplied from under 15 in 1965 to over 430 in 1991. During this period, often working out with the mainstream health system, the hospices actively sought to transform terminal care. More recently a process of diversification and legitimation has meant that hospices have become increasingly subject to mainstream influence. Using Weber's concept of charisma we examine the development of the hospice movement during this period of expansion. We suggest there are a number of factors leading to the routinization of hospice care including the ways in which it was sponsored and developed at the local level, and pressures toward bureaucratization and professionalization. We make links with recent developments in the health services. Finally we consider whether it is possible for the hospice movement to sustain its founding ideals. PMID:1529374
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…
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, 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, §...
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, 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, §...
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…
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.
Non-linear Models for Longitudinal Data
Serroyen, Jan; Molenberghs, Geert; Verbeke, Geert; Davidian, Marie
2009-01-01
While marginal models, random-effects models, and conditional models are routinely considered to be the three main modeling families for continuous and discrete repeated measures with linear and generalized linear mean structures, respectively, it is less common to consider non-linear models, let alone frame them within the above taxonomy. In the latter situation, indeed, when considered at all, the focus is often exclusively on random-effects models. In this paper, we consider all three families, exemplify their great flexibility and relative ease of use, and apply them to a simple but illustrative set of data on tree circumference growth of orange trees. PMID:20160890
[Premature ejaculation in urological routine practice].
Mathers, M J; Sommer, F; Degener, S; Brandt, A S; Roth, S
2013-01-01
Premature ejaculation is a frequent male sexual complaint or sexual disturbance found in urological practices and outpatient units. The frequency in the individual practices varies considerably. In large studies the prevalence is strongly dependent on the definition and ranges between 3% and 25%. Subjectively, the inability to delay ejaculation and the distress resulting from it, is relevant for the patient and his partner. Intravaginal ejaculation latency time (IELT) is used as an objective parameter. Nevertheless, in the everyday routine practice this objective parameter is not practical. Clinically 2 questionnaires have asserted themselves (Premature Ejaculation Profile and Index of Premature Ejaculation). Studies have shown that the self-assessment of patients correlates relatively well with the objective IELT measured by means of a stopwatch. Beside topical anaesthetics and elective serotonin reuptake inhibitors (SSRI), especially Dapexetine which has been approved in Germany since 2009, are treatment options. These drugs differ particularly in their use (daily or on-demand) and their effectiveness (measured by x-fold increase of IELT). This article deals with the clinical approach to EP. Beside the definition, prevalence, aetiology and neurophysiology of EP, the different pharmacological therapies as well as the guidelines of the International Society for Sexual Medicine are discussed. PMID:23381878
Peri-colonic haematoma following routine colonoscopy
Page, Felicity; Adedeji, Olfunso
2015-01-01
Introduction We present a case of an extra-luminal haematoma following routine colonoscopy. This case highlights an uncommon but potentially life threatening complication in which there is little published literature to date. Presentation of case A 73 year old male presented with abdominal pain and a reduction in haemoglobin following an uneventful colonoscopy. The imaging had been required as part of colorectal cancer follow up. Initial differential diagnosis included colonic perforation and the patient was admitted for further investigations. Same day CT scan imaging revealed an extra-luminal haematoma in the mid descending colon. The patient was managed non-operatively and was discharged with antibiotics following a period of observation. Discussion Colonoscopy is a highly effective imaging modality for direct visualisation of the lower gastrointestinal tract and for simultaneous diagnostic or therapeutic interventions. In recent years the use of colonoscopy has increased greatly, this is largely due to an increasingly aging population, increased availability of the resource and as a consequence of the implementation of the Bowel Cancer Screening Programme. Extra-colonic bleeding following colonoscopy is rare. Causes that have been identified in the literature include splenic injury, mesenteric tears, hepatic injury and retroperitoneal haemorrhage. To the authors' knowledge, there is very little published literature specifically on isolated peri-colonic haematomas following colonoscopy. Conclusion This case highlights an unusual but potentially life threatening complication following colonoscopy. Endoscopists and clinicians should be aware of the diagnosis to allow for early recognition and appropriate management. PMID:26900460
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.
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. PMID:6917733
Routine ultrasound surveillance after carotid endarterectomy.
Pratesi, C; Pulli, R; Ferlaino, E; Michelagnoli, S; Bernacchi, R; Borgioloi, F; Nuzzaci, G
1996-02-01
Ultrasounds (US) are employed in preoperative carotid disease diagnosis and in carotid endarterectomy (CEA) follow-up. The authors present their experience about postoperative modifications in CEA site with US evaluation with particular interest in restenosis. Clinical and instrumental examinations were performed at intervals 1, 3, 6, 12, and 24 months following surgery. Follow-up data were available on 189 CEAs. In 58 cases a primary closure was performed, whereas in the other 131 cases, a patch was applied. 15 restenosis (7.9%) were seen during the follow-up control period with 2 cases of haemodynamic restenosis (1%). Good results were recorded with PTFE patch angioplasty (restenosis 4.4%), instead of vein (restenosis 14.2%) and a biosynthetic material called Omniflow (restenosis 9.5%). A vein patch dilatation was encountered in 13 applications (30.9%). In conclusion the routine application of US after carotid endarterectomy allowed us to monitor the evolution of the repair processes and of the stenotic lesions from the very beginning. PMID:8606212
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).
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.
Routman, Justin S.; Willig, James H.; Westfall, Andrew O.; Abroms, Sarah R.; Varshney, Mohit; Adusumilli, Sunil; Allison, Jeroan J.; Savage, Karen G.; Saag, Michael S.; Mugavero, Michael J.
2009-01-01
Summary The generalizability of clinical trial findings (efficacy) to routine care (effectiveness) may be limited. The present study found similar first year virologic and CD4 outcomes among antiretroviral-naïve patients treated through routine care vs. those participating in clinical trials. Background The generalizability of clinical trial findings (efficacy) to routine care (effectiveness) may be limited due to study eligibility criteria and volunteer bias. While well chronicled in many conditions, the efficacy vs. effectiveness of antiretroviral therapy (ART) remains understudied. Methods A retrospective study of the UAB 1917 Clinic Cohort evaluated naïve patients starting ART between 1/1/00–12/31/06. Patients received ART through clinical trials or routine care. Multivariable logistic and linear regression models were fit to evaluate factors associated with virologic failure (VF=VL>50 copies/mL) and change from baseline CD4 count 6 and 12 months after ART initiation. Sensitivity analyses evaluated the impact of missing data on outcomes. Results Among 570 patients starting ART during the study period, 121 (21%) enrolled in clinical trials vs. 449 (79%) receiving ART via routine care. ART receipt through routine care was not associated with VF at either 6 (OR=1.00;95%CI=0.54–1.86) or 12 (OR=1.56;95%CI=0.80–3.05) months in primary analyses. No significant differences in CD4 count responses at 6 and 12 months were observed. Conclusions Though marked differences in efficacy vs. effectiveness have been observed in the therapeutic outcomes of other conditions, our analyses found no evidence of such divergence among our patients initiating antiretroviral therapy for HIV. PMID:20067423
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.
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.
Correcting the NICMOS count-rate dependent non-linearity
NASA Astrophysics Data System (ADS)
de Jong, Roelof S.
2006-03-01
We describe a routine to correct NICMOS imaging data for the NICMOS count-rate dependent non-linearity recently discovered by Bohlin et al. (2005) and quantified by deJong et al. (2006) and Bohlin et al. (2006). The routine has been implemented in the python scripting language and is callable from the shell command line and from iraf. The routine corrects NICMOS count-rate images assuming the non-linearity follows a powerlaw behavior. The wavelength dependence of the non-linearity is interpolated between the measured points of de Jong et al. (2006) and Bohlin et al. (2006) if necessary. The count rates in the output images are modified and hence the standard NICMOS calibration zero-points are no longer valid. New calibration zero-points have been derived from standard star images corrected with the routine. The routine was tested on the lamp-on/off data used in de Jong et al. (2006) to measure the non-linearity effect. We apply the correction to the NGC1850 stellar cluster field and the Hubble Ultra Deep Field (HUDF) to show the magnitude offsets expected due to the non-linearity on objects with a range in luminosity and surface brightness.
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.
Linearly Forced Isotropic Turbulence
NASA Technical Reports Server (NTRS)
Lundgren, T. S.
2003-01-01
Stationary isotropic turbulence is often studied numerically by adding a forcing term to the Navier-Stokes equation. This is usually done for the purpose of achieving higher Reynolds number and longer statistics than is possible for isotropic decaying turbulence. It is generally accepted that forcing the Navier-Stokes equation at low wave number does not influence the small scale statistics of the flow provided that there is wide separation between the largest and smallest scales. It will be shown, however, that the spectral width of the forcing has a noticeable effect on inertial range statistics. A case will be made here for using a broader form of forcing in order to compare computed isotropic stationary turbulence with (decaying) grid turbulence. It is shown that using a forcing function which is directly proportional to the velocity has physical meaning and gives results which are closer to both homogeneous and non-homogeneous turbulence. Section 1 presents a four part series of motivations for linear forcing. Section 2 puts linear forcing to a numerical test with a pseudospectral computation.
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.
Sitagliptin: Is It Effective in Routine Clinical Practice?
Mohan Dallumal, Rita; Chua, Siew Siang; Wu, David Bin-Chia; Vethakkan, Shireene Ratna
2015-01-01
Aim. The present study was conducted to determine the glycaemic effects of sitagliptin in type 2 diabetes patients. Methods. Data was collected from patient medical records of a major teaching hospital in Malaysia, from 2009 to 2012. Glycated hemoglobin (HbA1c) values prior to and up to 12 months after the initiation of sitagliptin were analysed. The change in HbA1c values was accounted for based on a generalized linear model generated using the Generalized Estimating Equations (GEE) method. Results and Discussion. Of the 457 patients, 53.6% were elderly and 81.4% were overweight. The mean HbA1c (standard deviation) before initiation of sitagliptin was 8.5 (1.4)%. This dropped to 7.7 (1.4)%, 3 to 6 months after initiation of sitagliptin, with a mean difference of 0.8% (95% confidence interval (CI): 0.7–1.0; P < 0.001). However, this value increased to 8.0 (1.7)% after 7 to 12 months on sitagliptin (P = 0.002) with a mean difference from baseline of 0.6% (95% CI: 0.4–0.7; P < 0.001). Conclusion. In routine clinical practice, sitagliptin produces a significant reduction in mean HbA1c (0.8%) within the first 6 months of use which corresponds to efficacy data obtained in controlled clinical trials. However, this reduction was lesser, 7 to 12 month later. PMID:26089904
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…
Routine Activities and Victimization at School: The Significance of Gender
ERIC Educational Resources Information Center
Popp, Ann Marie; Peguero, Anthony A.
2011-01-01
Routine activities theory has not fully considered the role of gender in shaping victimization and yet, the research literature clearly demonstrates that gender is associated with an individual's risk of victimization. In addition to the pervasive effect of gender on victimization, gender shapes an individual's daily routines and thus may create a…
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…
32 CFR 318.14 - Blanket routine uses.
Code of Federal Regulations, 2010 CFR
2010-07-01
... 32 National Defense 2 2010-07-01 2010-07-01 false Blanket routine uses. 318.14 Section 318.14 National Defense Department of Defense (Continued) OFFICE OF THE SECRETARY OF DEFENSE (CONTINUED) PRIVACY PROGRAM DEFENSE THREAT REDUCTION AGENCY PRIVACY PROGRAM § 318.14 Blanket routine uses. (a) Blanket...
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…
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…
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 493.841 - 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, 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, 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, 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, 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 493.1267 - 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...
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 493.841 - 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...
Eating routines. Embedded, value based, modifiable, and reflective.
Jastran, Margaret M; Bisogni, Carole A; Sobal, Jeffery; Blake, Christine; Devine, Carol M
2009-02-01
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-h 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
32 CFR 1701.31 - General routine uses.
Code of Federal Regulations, 2010 CFR
2010-07-01
... 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...
32 CFR 1701.31 - General routine uses.
Code of Federal Regulations, 2012 CFR
2012-07-01
... 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...
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...
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…
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)…
15 CFR 923.84 - Routine program changes.
Code of Federal Regulations, 2011 CFR
2011-01-01
... a routine program change. Failure to notify a State in writing within 4 weeks of receipt of notice... Programs § 923.84 Routine program changes. (a) Further detailing of a State's program that is the result of implementing provisions approved as part of a State's approved management program, that does not result in...
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,…
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…
Computer routine adds plotting capabilities to existing programs
NASA Technical Reports Server (NTRS)
Harris, J. C.; Linnekin, J. S.
1966-01-01
PLOTAN, a generalized plot analysis routine written for the IBM 7094 computer, minimizes the difficulties in adding plot capabilities to large existing programs. PLOTAN is used in conjunction with a binary tape writing routine and has the ability to plot any variable on the intermediate binary tape as a function of any other.
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,…
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…
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
Optimized remedial groundwater extraction using linear programming
Quinn, J.J.
1995-12-31
Groundwater extraction systems are typically installed to remediate contaminant plumes or prevent further spread of contamination. These systems are expensive to install and maintain. A traditional approach to designing such a wellfield uses a series of trial-and-error simulations to test the effects of various well locations and pump rates. However, the optimal locations and pump rates of extraction wells are difficult to determine when objectives related to the site hydrogeology and potential pumping scheme are considered. This paper describes a case study of an application of linear programming theory to determine optimal well placement and pump rates. The objectives of the pumping scheme were to contain contaminant migration and reduce contaminant concentrations while minimizing the total amount of water pumped and treated. Past site activities at the area 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 budget as groundwater discharge from the pits. Optimization of the containment pumping scheme was intended to meet three goals: (1) prevent discharge of contaminated groundwater to the wetland, (2) minimize the total water pumped and treated (cost benefit), and (3) avoid dewatering of the wetland (cost and ecological benefits). Possible well locations were placed at known source areas. To constrain the problem, the optimization program was instructed to prevent any flow toward the wetland along a user-specified border. In this manner, the optimization routine selects well locations and pump rates so that a groundwater divide is produced along this boundary.
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.
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.
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.
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)
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.
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
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. PMID:21319879
[Routine episiotomy in modern obstetrics. Is it necessary?].
Korczyński, Jerzy
2002-01-01
The study presents a literature review on the benefits and risk of the routine episiotomy during the second stage of labour. Perineal trauma complications as well as perinatal outcomes are discussed. The risk of stress incontinence and sexual dysfunction are described. New techniques for improve of perinatal outcomes and prevention of post partum incontinence are described. Routine episiotomy gives poor effects in many cases. Perineal massage during pregnancy, waterbirth, are most interesting methods to avoid routine episiotomy and improve the quality of life in post partum women. PMID:12152258
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
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.
Task Force: Routine Genital Herpes Screening Not Recommended
... https://medlineplus.gov/news/fullstory_160205.html Task Force: Routine Genital Herpes Screening Not Recommended Unless someone ... 2, 2016 (HealthDay News) -- A U.S. federal task force is prepared to recommend that teens, adults and ...
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.
A crystal routine for collimation studies in circular proton accelerators
NASA Astrophysics Data System (ADS)
Mirarchi, D.; Hall, G.; Redaelli, S.; Scandale, W.
2015-07-01
A routine has been developed to simulate interactions of protons with bent crystals in a version of SixTrack for collimation studies. This routine is optimized to produce high-statistics tracking simulations for a highly efficient collimation system, like the one of the CERN Large Hadron Collider (LHC). The routine has recently been reviewed and improved through a comparison with experimental data, benchmarked against other codes and updated by adding better models of low-probability interactions. In this paper, data taken with 400 GeV/c proton beams at the CERN-SPS North Area are used to verify the prediction of the routine, including the results of a more recent analysis.
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. PMID:26737536
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 ...
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.
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
Adoption of routine telemedicine in Norway: the current picture
Zanaboni, Paolo; Knarvik, Undine; Wootton, Richard
2014-01-01
Background Telemedicine appears to be ready for wider adoption. Although existing research evidence is useful, the adoption of routine telemedicine in healthcare systems has been slow. Objective We conducted a study to explore the current use of routine telemedicine in Norway, at national, regional, and local levels, to provide objective and up-to-date information and to estimate the potential for wider adoption of telemedicine. Design A top-down approach was used to collect official data on the national use of telemedicine from the Norwegian Patient Register. A bottom-up approach was used to collect complementary information on the routine use of telemedicine through a survey conducted at the five largest publicly funded hospitals. Results Results show that routine telemedicine has been adopted in all health regions in Norway and in 68% of hospitals. Despite being widely adopted, the current level of use of telemedicine is low compared to the number of face-to-face visits. Examples of routine telemedicine can be found in several clinical specialties. Most services connect different hospitals in secondary care, and they are mostly delivered as teleconsultations via videoconference. Conclusions Routine telemedicine in Norway has been widely adopted, probably for geographical reasons, as in other settings. However, the level of use of telemedicine in Norway is rather low, and it has significant potential for further development as an alternative to face-to-face outpatient visits. This study is a first attempt to map routine telemedicine at regional, institutional, and clinical levels, and it provides useful information to understand the adoption of telemedicine in routine healthcare and to measure change in future updates. PMID:24433942
Unusual Foreign Body in a Routine Lateral Cephalogram
James, Jean; S, Praveen; V.P, Latheef; S, Sreehari
2015-01-01
Routine radiographs made in the orthodontic office can often give way to detection and diagnosis of unusual syndromes, signs or foreign bodies. A case report of one such accidental detection of a very unusual foreign body within the nasal cavity of an orthodontic patient has been presented here to emphasize the importance of routine radiographic views, which over and above aiding in Orthodontic diagnosis, can also often detect potentially life threatening problems in the Oro-facial region. PMID:25859532
Survey of US Correctional Institutions for Routine HCV Testing
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
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
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. PMID:25393186
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
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.
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.
Routine or targeted HIV screening of Indonesian prisoners.
Nelwan, Erni Juwita; Isa, Ahmad; Alisjahbana, Bachti; Triani, Nurlita; Djamaris, Iqbal; Djaja, Ilham; Pohan, Herdiman T; Zwanikken, Prisca; Crevel, Reinout van; van der Ven, Andre; Meheus, Andre
2016-03-14
Purpose - Routine HIV screening of prisoners is generally recommended, but rarely implemented in low-resource settings. Targeted screening can be used as an alternative. Both strategies may provide an opportunity to start HIV treatment but no formal comparisons have been done of these two strategies. The paper aims to discuss these issues. Design/methodology/approach - The authors compared yield and costs of routine and targeted screening in a narcotic prison in Indonesia. Routine HIV screening was done for all incoming prisoners from August 2007-February 2009, after it was switched for budgetary reasons to targeted ("opt-out") HIV screening of inmates classified as people who inject drugs (PWIDs), and "opt-in" HIV testing for all non-PWIDs. Findings - During routine screening 662 inmates were included. All 115 PWIDs and 93.2 percent of non-PWIDs agreed to be tested, 37.4 percent and 0.4 percent respectively were HIV-positive. During targeted screening (March 2009-October 2010), of 888 inmates who entered prison, 107 reported injecting drug use and were offered HIV testing, of whom 31 (29 percent) chose not to be tested and 25.0 percent of those tested were HIV-positive. Of 781 non-PWIDs, 187 (24 percent) came for testing (opt-in), and 2.1 percent were infected. During targeted screening fewer people admitted drug use (12.0 vs 17.4 percent). Routine screening yielded twice as many HIV-infected subjects (45 vs 23). The estimated cost per detected HIV infection was 338 USD for routine and 263 USD for targeted screening. Originality/value - In a resource limited setting like Indonesia, routine HIV screening in prison is feasible and more effective than targeted screening, which may be stigmatizing. HIV infections that remain unrecognized can fuel ongoing transmission in prison and lead to unnecessary disease progression and deaths. PMID:26933989
Routine hand doses vs monitoring regulations at a nuclear power plant.
Huggins, T R; Watson, J E
1984-04-01
Hand radiation doses to workers at a nuclear power plant were monitored in this study to evaluate compliance with dose limits and to determine whether hand monitoring on a routine basis is necessary. Two hundred in-plant workers at Carolina Power and Light Co.'s H.B. Robinson Steam Electric Generating Plant were monitored with a ring TLD dosimeter on each hand for four months during routine plant operations. Study participants included plant operators, electricians, mechanics, health physics technicians and decontamination personnel. Ring dosimeters were worn, in addition to whole-body TLD dosimeters, at all times workers were in radiation control areas. Hand dosimeters were read on the same monthly schedule as the whole-body dosimeters to ensure correlation of exposure periods. The results of the analysis of hand-dose data obtained for these workers are summarized as follows: (1) No worker's hand dose exceeded 25% of the allowable quarterly dose. (2) Ninety-nine percent of hand doses were less than 600 mrem/month. (3) The highest hand dose observed in any month was 1074 mrem which if received for three months, is below regulatory dose limits and below the dose value where monitoring is required. The highest actual hand dose observed in the last quarter of 1981 was 1335 mrem. (4) Examination of hand dose to whole-body dose ratios revealed that if the whole-body dose limit is approached, hand doses are still below the dose level where monitoring is required. (5) A linear-regression analysis of hand and whole-body dose data provides the ability to predict hand doses from the whole-body doses. From these results, it is concluded that routine monitoring of hand doses is not required at the H.B. Robinson plant. This conclusion should also be applicable to routine operations at other similar nuclear plants. PMID:6706587
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.
On-line control models for the Stanford Linear Collider
Sheppard, J.C.; Helm, R.H.; Lee, M.J.; Woodley, M.D.
1983-03-01
Models for computer control of the SLAC three-kilometer linear accelerator and damping rings have been developed as part of the control system for the Stanford Linear Collider. Some of these models have been tested experimentally and implemented in the control program for routine linac operations. This paper will describe the development and implementation of these models, as well as some of the operational results.
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.
NASA Astrophysics Data System (ADS)
Young, T.
This book is intended to be used as a textbook in a one-semester course at a variety of levels. Because of self-study features incorporated, it may also be used by practicing electronic engineers as a formal and thorough introduction to the subject. The distinction between linear and digital integrated circuits is discussed, taking into account digital and linear signal characteristics, linear and digital integrated circuit characteristics, the definitions for linear and digital circuits, applications of digital and linear integrated circuits, aspects of fabrication, packaging, and classification and numbering. Operational amplifiers are considered along with linear integrated circuit (LIC) power requirements and power supplies, voltage and current regulators, linear amplifiers, linear integrated circuit oscillators, wave-shaping circuits, active filters, DA and AD converters, demodulators, comparators, instrument amplifiers, current difference amplifiers, analog circuits and devices, and aspects of troubleshooting.
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.
The role of routine follow-up after gynecological malignancy.
Kew, F M; Roberts, A P; Cruickshank, D J
2005-01-01
The objective of this article was to determine the evidence base for routine follow-up after gynecological malignancy. Only articles with a survival analysis were included. Relevant articles were identified by a comprehensive literature search of the main biomedical databases, hand searching of references of selected articles, and expert spotting of relevant journals and proceedings of international meetings. A two-stage extraction of data was undertaken. No prospective trials were identified. Twenty-nine retrospective case series analyses and one poster presentation met the inclusion criteria. Eight articles and one letter on endometrial cancer, six articles and one poster presentation on cervical cancer, and two articles in vulval cancer were reviewed. Only one article in endometrial cancer showed any survival benefit from routine follow-up, but it was of very poor methodologic quality. Two articles found a survival benefit from routine follow-up after cervical cancer. The two articles on vulval cancer did not find any survival benefit from routine review. There is no prospective research on the benefits of routine follow-up after gynecological cancer. Retrospective evidence calls in to question the benefit of universal follow-up. Prospective research is urgently needed. PMID:15882163
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
Social and Demographic Predictors of Preschoolers’ Bedtime Routines
Hale, Lauren; Berger, Lawrence M.; LeBourgeois, Monique K.; Brooks-Gunn, Jeanne
2009-01-01
Objective To examine associations of child and family sociodemographic characteristics with preschooler bedtime routines. Method We use parent-report data on 3,217 3-year-old children (48% black; 26% Hispanic; 26% white) from the Fragile Families and Child Wellbeing Study to examine whether child and family characteristics are associated with the presence, time, and consistency of bedtime routines. Results Over 80% of sample children have a bedtime yet only two-thirds follow it. After extensive controls for maternal education, family structure, and other household characteristics, Black and Hispanic children have later bedtimes than white children and reduced odds of using regular bedtimes (by 22% and 29%, respectively) and using bedtime routines (by 47% and 33%, respectively). Low maternal education, increased household size, and poverty are associated with decreased use of parent-child interactive and hygiene-related bedtime routines. Conclusion Children from disadvantaged households are less likely to have consistent bedtime routines than their more advantaged counterparts. This may contribute to later disparities in sleep quality, duration and timing, factors known to be associated with adverse behavioral, cognitive, and health outcomes. PMID:19745760
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
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)
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.
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.
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)
Routine Activities Preceding Adolescent Sexual Abuse of Younger Children.
Leclerc, Benoit; Felson, Marcus
2016-03-01
Adolescent abuse of younger children has long been recognized, but empirical research on the circumstances of this phenomenon is rare. This article examines how adolescent offenders find and gain access to victims, work out time alone with them, and set up or exploit settings for sexual contact. Prior researchers learned that adult sex offenders use certain routine activities to perform these tasks. The current research inquires whether adolescent offenders are similar. We administered Kaufman's Modus Operandi Questionnaire to a sample of 116 Canadian adolescent males undergoing treatment for a sexual offense against a child. Adolescent offenders follow routines similar to adults but are better able to use games and activities as a prelude to sexual abuse. We discuss how routine legal activities set the stage for activities and should be considered when devising situational prevention strategies. PMID:25060598
Solution of 3-dimensional time-dependent viscous flows. Part 1: Investigation of candidate algoriths
NASA Technical Reports Server (NTRS)
Weinberg, B. C.; Mcdonald, H.
1979-01-01
There is considerable interest in developing a numerical scheme for solving the time dependent viscous compressible three dimensional flow to aid in the design of helicopter rotors. Numerical algorithms are examined to determine their overall suitability for the efficient and routine solution of an appropriate system of partial differential equations. It is concluded that a consistently split time linearized block implicit scheme using either quintic B spline collocation or the generalized operator compact implicit approach to generate a fourth order accurate algorithm is particularly well suited for use on the present problem. High cell Reynolds number behavior leads to favoring the generalized operator compact implicit approach over the quintic B spline collocation method.
Monochromatic, Rosseland mean, and Planck mean opacity routine
NASA Astrophysics Data System (ADS)
Semenov, D.
2006-11-01
Several FORTRAN77 codes were developed to compute frequency-dependent, Rosseland and Planck mean opacities of gas and dust in protoplanetary disks. The opacities can be computed for an ensemble of dust grains having various compositions (ices, silicates, organics, etc), sizes, topologies (homogeneous/composite aggregates, homogeneous/layered/composite spheres, etc.), porosities, and dust-to-gas ratio. Several examples are available. In addition, a very fast opacity routine to be used in modeling of the radiative transfer in hydro simulations of disks is available upon request (10^8 routine calls require about 30s on Pentium 4 3.0GHz).
Value of routine histopathological examination of appendices in Hong Kong.
Chan, W; Fu, K H
1987-01-01
A retrospective study of the histopathological findings of more than 11,443 appendices submitted as surgical specimens over 14 years was performed in this department. In most cases routine histopathological examination added little clinically important information to other clinical and operative gross findings, but a variety of interesting and uncommon lesions were identified. In 85 cases clinically important pathological findings were first discovered on routine histopathological examination. These included enterobiasis, schistosomiasis, mucocele, trichuriasis, tuberculosis, ascariasis, endometriosis, mucinous cystadenoma, granuloma, carcinoid tumour, neuroma, clonorchiasis, primary adenocarcinoma and secondary carcinoma. PMID:3584486
NASA Technical Reports Server (NTRS)
Melcher, Kevin J.
2006-01-01
The Compressible Flow Toolbox is primarily a MATLAB-language implementation of a set of algorithms that solve approximately 280 linear and nonlinear classical equations for compressible flow. The toolbox is useful for analysis of one-dimensional steady flow with either constant entropy, friction, heat transfer, or Mach number greater than 1. The toolbox also contains algorithms for comparing and validating the equation-solving algorithms against solutions previously published in open literature. The classical equations solved by the Compressible Flow Toolbox are as follows: The isentropic-flow equations, The Fanno flow equations (pertaining to flow of an ideal gas in a pipe with friction), The Rayleigh flow equations (pertaining to frictionless flow of an ideal gas, with heat transfer, in a pipe of constant cross section), The normal-shock equations, The oblique-shock equations, and The expansion equations.
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.
Routine Metabolic Rate of Channel Catfish Ictalurus punctatus Fry
Technology Transfer Automated Retrieval System (TEKTRAN)
Channel catfish eggs are typically incubated at high density and are often subjected to sub-optimum dissolved oxygen (DO) concentrations while in the hatchery. Since DO plays an important role in the development, hatch rate, and growth of catfish eggs and fry, we measured routine metabolic rate of ...
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…
Classroom Ordering and the Situational Imperatives of Routine and Ritual
ERIC Educational Resources Information Center
Diehl, David; McFarland, Daniel A.
2012-01-01
This article contends that the problem of classroom order rests less in the roles and compositions of classrooms than in the multidimensional nature of their social situations. Classroom order arises from the dynamic relationship between distinct situational requirements: the coordination of interaction into institutionalized patterns (routine)…
32 CFR 552.109 - Routine security controls.
Code of Federal Regulations, 2011 CFR
2011-07-01
... 32 National Defense 3 2011-07-01 2009-07-01 true Routine security controls. 552.109 Section 552.109 National Defense Department of Defense (Continued) DEPARTMENT OF THE ARMY MILITARY RESERVATIONS AND NATIONAL CEMETERIES REGULATIONS AFFECTING MILITARY RESERVATIONS Regulation Controlling the Access to the Fort Lewis Main Cantonment Area...
Cervical discospondylitis in 2 Great Dane puppies following routine surgery.
Finnen, Andrea; Blond, Laurent; Parent, Joane
2012-05-01
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
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…
Asymptomatic Gastric Band Erosion Detected during Routine Gastroduodenoscopy.
Yun, Gee Young; Kim, Woo Sub; Kim, Hye Jin; Kang, Sun Hyung; Moon, Hee Seok; Sung, Jae Kyu; Jeong, Hyun Yong
2016-05-01
The incidence of gastric band erosion has decreased to 1%. Gastric band erosion can manifest with various clinical symptoms, although some patients remain asymptomatic. We present a case of a mostly asymptomatic patient who was diagnosed with gastric band erosion during a routine health check-up. A 32-year-old man without any underlying diseases except for non-alcoholic fatty liver underwent laparoscopic adjustable gastric band surgery in 2010. He had no significant complications postoperatively. He underwent routine health check-ups with near-normal gastroduodenoscopic findings through 2014. However, in 2015, routine gastroduodenoscopy showed that the gastric band had eroded into the stomach. His gastric band was removed laparoscopically, and the remaining gastric ulcer perforation was repaired using an omental patch. Due to the early diagnosis, the infection was not serious. The patient was discharged on postoperative day 3 with oral antibiotics. This patient was fortunately diagnosed early by virtue of a routine health check-up; thus, eliminating the possibility of serious complications. PMID:26867553
Asymptomatic Gastric Band Erosion Detected during Routine Gastroduodenoscopy
Yun, Gee Young; Kim, Woo Sub; Kim, Hye Jin; Kang, Sun Hyung; Moon, Hee Seok; Sung, Jae Kyu; Jeong, Hyun Yong
2016-01-01
The incidence of gastric band erosion has decreased to 1%. Gastric band erosion can manifest with various clinical symptoms, although some patients remain asymptomatic. We present a case of a mostly asymptomatic patient who was diagnosed with gastric band erosion during a routine health check-up. A 32-year-old man without any underlying diseases except for non-alcoholic fatty liver underwent laparoscopic adjustable gastric band surgery in 2010. He had no significant complications postoperatively. He underwent routine health check-ups with near-normal gastroduodenoscopic findings through 2014. However, in 2015, routine gastroduodenoscopy showed that the gastric band had eroded into the stomach. His gastric band was removed laparoscopically, and the remaining gastric ulcer perforation was repaired using an omental patch. Due to the early diagnosis, the infection was not serious. The patient was discharged on postoperative day 3 with oral antibiotics. This patient was fortunately diagnosed early by virtue of a routine health check-up; thus, eliminating the possibility of serious complications. PMID:26867553
32 CFR 552.109 - Routine security controls.
Code of Federal Regulations, 2010 CFR
2010-07-01
... 32 National Defense 3 2010-07-01 2010-07-01 true Routine security controls. 552.109 Section 552.109 National Defense Department of Defense (Continued) DEPARTMENT OF THE ARMY MILITARY RESERVATIONS AND NATIONAL CEMETERIES REGULATIONS AFFECTING MILITARY RESERVATIONS Regulation Controlling the Access to the Fort Lewis Main Cantonment Area...
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 552.109 - Routine security controls.
Code of Federal Regulations, 2012 CFR
2012-07-01
... 32 National Defense 3 2012-07-01 2009-07-01 true Routine security controls. 552.109 Section 552.109 National Defense Department of Defense (Continued) DEPARTMENT OF THE ARMY MILITARY RESERVATIONS AND NATIONAL CEMETERIES REGULATIONS AFFECTING MILITARY RESERVATIONS Regulation Controlling the...
32 CFR 552.109 - Routine security controls.
Code of Federal Regulations, 2013 CFR
2013-07-01
... 32 National Defense 3 2013-07-01 2013-07-01 false Routine security controls. 552.109 Section 552.109 National Defense Department of Defense (Continued) DEPARTMENT OF THE ARMY MILITARY RESERVATIONS AND NATIONAL CEMETERIES REGULATIONS AFFECTING MILITARY RESERVATIONS Regulation Controlling the...
32 CFR 552.109 - Routine security controls.
Code of Federal Regulations, 2014 CFR
2014-07-01
... 32 National Defense 3 2014-07-01 2014-07-01 false Routine security controls. 552.109 Section 552.109 National Defense Department of Defense (Continued) DEPARTMENT OF THE ARMY MILITARY RESERVATIONS AND NATIONAL CEMETERIES REGULATIONS AFFECTING MILITARY RESERVATIONS Regulation Controlling the...
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…
15 CFR 923.84 - Routine program changes.
Code of Federal Regulations, 2010 CFR
2010-01-01
... the routine program change and identify any enforceable policies to be added to the management program... MANAGEMENT COASTAL ZONE MANAGEMENT PROGRAM REGULATIONS Amendments to and Termination of Approved Management... implementing provisions approved as part of a State's approved management program, that does not result in...
15 CFR 923.84 - Routine program changes.
Code of Federal Regulations, 2013 CFR
2013-01-01
... the routine program change and identify any enforceable policies to be added to the management program... MANAGEMENT COASTAL ZONE MANAGEMENT PROGRAM REGULATIONS Amendments to and Termination of Approved Management... implementing provisions approved as part of a State's approved management program, that does not result in...
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
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…
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. PMID:6617033
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,…
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…
Assessment of routine malaria diagnosis in the Venezuelan Amazon.
Metzger, W G; Vivas-Martínez, S; Giron, A; Vaccari, E; Campos, E; Rodríguez, I; Miranda, E; Terán, E; Olivo, L; Magris, M
2011-05-01
The quality of routine malaria diagnosis is a crucial topic of malaria control. The aim of this assessment was to monitor and evaluate the quality of routine malaria diagnosis in Amazonas (Venezuela) and to improve the quality control system. The traditional non-blinded quality control system was found to be overburdened with diagnostic samples. A modified sampling system with fewer samples to be tested was proposed. Expert microscopists blindly double-checked 1000 slides and 550 rapid diagnostic tests (RDT) (OptiMAL-IT) from health posts (HP). For Plasmodium vivax, HP microscopy and OptiMAL-IT showed sensitivies of 86% and 63%, respectively. For P. falciparum, HP microscopy and OptiMAL-IT showed sensitivities of 68% and 89%, respectively. Both methods lost accuracy when fewer parasites occurred in the sample. HP microscopists from different municipalities displayed significant differences in diagnostic quality. Overall, quality of routine malaria diagnosis in the Venezuelan Amazon is good but not optimal. The change from the traditional non-blinded quality control system to blinded cross-checking of a minimal selection of samples is - comparatively - a low cost intervention with possibly high impact on the quality of routine malaria diagnosis. The introduction of RDTs should be discussed carefully in order not to displace an existing network of HP microscopists. PMID:21376357
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…
42 CFR 414.220 - Inexpensive or routinely purchased items.
Code of Federal Regulations, 2012 CFR
2012-10-01
... routinely purchased items. (a) Definitions. (1) Inexpensive equipment means equipment the average purchase... purchased equipment means equipment that was acquired by purchase on a national basis at least 75 percent of... lump sum amount for purchase of the item based on the applicable fee schedule amount. (2)...
42 CFR 414.220 - Inexpensive or routinely purchased items.
Code of Federal Regulations, 2014 CFR
2014-10-01
... average purchase price of which did not exceed $150 during the period July 1986 through June 1987. (2) Routinely purchased equipment means equipment that was acquired by purchase on a national basis at least 75... basis or in a lump sum amount for purchase of the item based on the applicable fee schedule amount....
42 CFR 414.220 - Inexpensive or routinely purchased items.
Code of Federal Regulations, 2013 CFR
2013-10-01
... routinely purchased items. (a) Definitions. (1) Inexpensive equipment means equipment the average purchase... purchased equipment means equipment that was acquired by purchase on a national basis at least 75 percent of... lump sum amount for purchase of the item based on the applicable fee schedule amount. (2)...
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…
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.
NASA/MSFC NASTRAN auxiliary I/O routines
NASA Technical Reports Server (NTRS)
Tagg, M.; Thornton, B.
1983-01-01
Since the initial installation of NASTRAN on the UNIVAC 1100/82 computer at the Marshall Space Flight Center (MSFC), a number of local codes have been incorporated as user routines. This paper describes four of these codes and how interested users may obtain additional information.
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,…
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…
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…
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.
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.
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.
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.
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. PMID:12804218
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 mi2 and has an average flow of about 182,000 ft3/s. 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 a function of flow at the
Powerful Electromechanical Linear Actuator
NASA Technical Reports Server (NTRS)
Cowan, John R.; Myers, William N.
1994-01-01
Powerful electromechanical linear actuator designed to replace hydraulic actuator that provides incremental linear movements to large object and holds its position against heavy loads. Electromechanical actuator cleaner and simpler, and needs less maintenance. Two principal innovative features that distinguish new actuator are use of shaft-angle resolver as source of position feedback to electronic control subsystem and antibacklash gearing arrangement.
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.
Linear Equations: Equivalence = Success
ERIC Educational Resources Information Center
Baratta, Wendy
2011-01-01
The ability to solve linear equations sets students up for success in many areas of mathematics and other disciplines requiring formula manipulations. There are many reasons why solving linear equations is a challenging skill for students to master. One major barrier for students is the inability to interpret the equals sign as anything other than…
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.
Linear models: permutation methods
Cade, B.S.
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]...
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.