Science.gov

Sample records for quantitative flow visualization

  1. Qualitative and quantitative flow visualization technique using ozone

    NASA Technical Reports Server (NTRS)

    Dickerson, R. R.; Stedman, D. H.

    1979-01-01

    The paper describes a new flow-visualization technique based on the absorption of ultraviolet light by ozone. Ozone is an excellent tracer, because as a gas it has the same effective physical properties as air. Ozone strongly absorbs the principal line (253.7 nm) of a mercury lamp, so that when an ozone-traced flow passes between a mercury lamp and a fluorescent screen, a sharp, shadow-like image of the ozone tracer is cast on the screen. Quantitative photometry can be carried out by replacing the screen with ultraviolet detectors that yield the path-integrated column density of ozone in the flow. High-speed quantitative point monitoring (10 Hz at 10 ppb O3) is possible with capillary probes and chemiluminescent analysis.

  2. Photogrammetric and image processing aspects in quantitative flow visualization.

    PubMed

    Machacek, Matthias; Rosgen, Thomas

    2002-10-01

    The development of a measurement system for the visualization, topological classification, and quantitative analysis of complex flows in large-scale wind tunnel experiments is described. A new approach was sought in which the topological features of the flow (e.g., stream lines, separation and reattachment regions, stagnation points, and vortex lines) were extracted directly and preferably visualized in real-time in a virtual wind tunnel environment. The system was based on a stereo arrangement of two CCD cameras. A frame rate of 120 fps allowed measurements at high flow velocities. The paper focuses on the problem of fast and accurate reconstruction of path lines of helium filled soap bubbles in three dimensions (3D). A series of simple algorithmic steps was employed to ensure fast data processing. These included fast image segmentation, a spline approximation of the path lines, a camera model, point correspondence building, calculation of path line points in 3D and creation of a three-dimensional spline representation. The path lines, which contained both velocity and topological information, were analyzed to extract the relevant information.

  3. Photogrammetric and image processing aspects in quantitative flow visualization.

    PubMed

    Machacek, Matthias; Rosgen, Thomas

    2002-10-01

    The development of a measurement system for the visualization, topological classification, and quantitative analysis of complex flows in large-scale wind tunnel experiments is described. A new approach was sought in which the topological features of the flow (e.g., stream lines, separation and reattachment regions, stagnation points, and vortex lines) were extracted directly and preferably visualized in real-time in a virtual wind tunnel environment. The system was based on a stereo arrangement of two CCD cameras. A frame rate of 120 fps allowed measurements at high flow velocities. The paper focuses on the problem of fast and accurate reconstruction of path lines of helium filled soap bubbles in three dimensions (3D). A series of simple algorithmic steps was employed to ensure fast data processing. These included fast image segmentation, a spline approximation of the path lines, a camera model, point correspondence building, calculation of path line points in 3D and creation of a three-dimensional spline representation. The path lines, which contained both velocity and topological information, were analyzed to extract the relevant information. PMID:12495995

  4. Quantitative visualization of coherent flow structures in alluvial channels using multibeam echo-sounding

    NASA Astrophysics Data System (ADS)

    Parsons, D. R.; Simmons, S.; Best, J.

    2010-12-01

    Multibeam Echo-Sounder systems have developed rapidly over recent decades and are routinely deployed to provide high-resolution bathymetric details in range of aquatic environments. Modern data handling and storage technologies now facilitate the logging of the raw acoustic back-scatter information that was previously discarded by these systems. This paper describes methodologies that exploit this logging capability to quantify the concentration and dynamics of suspended sediment within the water column and presents a novel method that also allows for quantification of 2D flow velocities. This development provides a multi-purpose tool for the holistic surveying of the process linkages between flow, sediment transport and bed morphology. The application of this new technique is illustrated with reference to flow over alluvial sand dunes, which allows, for the first time in a field study, quantitative visualization of larg-scale, whole flow field, turbulent coherent flow structures, associated with the dune leeside, that are responsible for suspending bed sediment. This methodology holds great potential for use in a wide range of aqueous geophysical flows. CFS captured by MBES in the lee of an alluvial dune. Contours of suspended sediment concentration and superimposed 2D flow velocity vectors

  5. Quantitative visualization of asymmetric gas flow in constricted microchannels by using pressure-sensitive paint

    NASA Astrophysics Data System (ADS)

    Huang, Chih-Yung; Chen, Ying-Hsuan; Wan, Shaw-An; Wang, Yu-Chuan

    2016-10-01

    Asymmetric flow in constricted microchannel devices was quantitatively investigated using a pressure-sensitive paint (PSP) technique. For microchannel devices with constriction ratios of 2 : 1 and 5 : 1, detailed pressure maps for the region around the constriction structure were obtained and enabled visualization of the flow field. Symmetric flow was observed in the microchannel device with a constriction ratio of 2 : 1 at the Reynolds number range 2-165. In the microchannel with a constriction ratio of 5 : 1, a deflected flow pattern was clearly identified from PSP measurements at Reynolds numbers exceeding 107. Furthermore, PSP measurements showed a pressure difference of up to 2.5 kPa between the two lateral locations corresponding to y  =  ±0.15 W (W is the microchannel width) downstream of the constriction at a Reynolds number of 279. The pressure difference resulted from asymmetric bifurcation of the flow.

  6. A new methodology for the quantitative visualization of coherent flow structures in alluvial channels using multibeam echo-sounding (MBES)

    NASA Astrophysics Data System (ADS)

    Best, Jim; Simmons, Stephen; Parsons, Daniel; Oberg, Kevin; Czuba, Jonathan; Malzone, Chris

    2010-03-01

    In order to investigate the interactions between turbulence and suspended sediment transport in natural aqueous environments, we ideally require a technique that allows simultaneous measurement of fluid velocity and sediment concentration for the whole flow field. Here, we report on development of a methodology using the water column acoustic backscatter signal from a multibeam echo sounder to simultaneously quantify flow velocities and sediment concentrations. The application of this new technique is illustrated with reference to flow over the leeside of an alluvial sand dune, which allows, for the first time in a field study, quantitative visualization of large-scale, whole flow field, turbulent coherent flow structures associated with the dune leeside that are responsible for suspending bed sediment. This methodology holds great potential for use in a wide range of aqueous geophysical flows.

  7. A new methodology for the quantitative visualization of coherent flow structures in alluvial channels using multibeam echo-sounding (MBES)

    USGS Publications Warehouse

    Best, Jim; Simmons, Stephen; Parsons, Daniel; Oberg, Kevin; Czuba, Jonathan; Malzone, Chris

    2010-01-01

    In order to investigate the interactions between turbulence and suspended sediment transport in natural aqueous environments, we ideally require a technique that allows simultaneous measurement of fluid velocity and sediment concentration for the whole flow field. Here, we report on development of a methodology using the water column acoustic backscatter signal from a multibeam echo sounder to simultaneously quantify flow velocities and sediment concentrations. The application of this new technique is illustrated with reference to flow over the leeside of an alluvial sand dune, which allows, for the first time in a field study, quantitative visualization of large-scale, whole flow field, turbulent coherent flow structures associated with the dune leeside that are responsible for suspending bed sediment. This methodology holds great potential for use in a wide range of aqueous geophysical flows.

  8. Improved quantitative visualization of hypervelocity flow through wavefront estimation based on shadow casting of sinusoidal gratings.

    PubMed

    Medhi, Biswajit; Hegde, Gopalakrishna M; Gorthi, Sai Siva; Reddy, Kalidevapura Jagannath; Roy, Debasish; Vasu, Ram Mohan

    2016-08-01

    A simple noninterferometric optical probe is developed to estimate wavefront distortion suffered by a plane wave in its passage through density variations in a hypersonic flow obstructed by a test model in a typical shock tunnel. The probe has a plane light wave trans-illuminating the flow and casting a shadow of a continuous-tone sinusoidal grating. Through a geometrical optics, eikonal approximation to the distorted wavefront, a bilinear approximation to it is related to the location-dependent shift (distortion) suffered by the grating, which can be read out space-continuously from the projected grating image. The processing of the grating shadow is done through an efficient Fourier fringe analysis scheme, either with a windowed or global Fourier transform (WFT and FT). For comparison, wavefront slopes are also estimated from shadows of random-dot patterns, processed through cross correlation. The measured slopes are suitably unwrapped by using a discrete cosine transform (DCT)-based phase unwrapping procedure, and also through iterative procedures. The unwrapped phase information is used in an iterative scheme, for a full quantitative recovery of density distribution in the shock around the model, through refraction tomographic inversion. Hypersonic flow field parameters around a missile-shaped body at a free-stream Mach number of ∼8 measured using this technique are compared with the numerically estimated values. It is shown that, while processing a wavefront with small space-bandwidth product (SBP) the FT inversion gave accurate results with computational efficiency; computation-intensive WFT was needed for similar results when dealing with larger SBP wavefronts. PMID:27505389

  9. Improved quantitative visualization of hypervelocity flow through wavefront estimation based on shadow casting of sinusoidal gratings.

    PubMed

    Medhi, Biswajit; Hegde, Gopalakrishna M; Gorthi, Sai Siva; Reddy, Kalidevapura Jagannath; Roy, Debasish; Vasu, Ram Mohan

    2016-08-01

    A simple noninterferometric optical probe is developed to estimate wavefront distortion suffered by a plane wave in its passage through density variations in a hypersonic flow obstructed by a test model in a typical shock tunnel. The probe has a plane light wave trans-illuminating the flow and casting a shadow of a continuous-tone sinusoidal grating. Through a geometrical optics, eikonal approximation to the distorted wavefront, a bilinear approximation to it is related to the location-dependent shift (distortion) suffered by the grating, which can be read out space-continuously from the projected grating image. The processing of the grating shadow is done through an efficient Fourier fringe analysis scheme, either with a windowed or global Fourier transform (WFT and FT). For comparison, wavefront slopes are also estimated from shadows of random-dot patterns, processed through cross correlation. The measured slopes are suitably unwrapped by using a discrete cosine transform (DCT)-based phase unwrapping procedure, and also through iterative procedures. The unwrapped phase information is used in an iterative scheme, for a full quantitative recovery of density distribution in the shock around the model, through refraction tomographic inversion. Hypersonic flow field parameters around a missile-shaped body at a free-stream Mach number of ∼8 measured using this technique are compared with the numerically estimated values. It is shown that, while processing a wavefront with small space-bandwidth product (SBP) the FT inversion gave accurate results with computational efficiency; computation-intensive WFT was needed for similar results when dealing with larger SBP wavefronts.

  10. Air flow visualization

    NASA Technical Reports Server (NTRS)

    1989-01-01

    Smoke Flow Visualization shows the flow of air around a model airfoil at 100 feet per second. Photograph and caption published in Winds of Change, 75th Anniversary NASA publication (page xi), by James Schultz.

  11. A qualitative and quantitative laser-based computer-aided flow visualization method. M.S. Thesis, 1992 Final Report

    NASA Technical Reports Server (NTRS)

    Canacci, Victor A.; Braun, M. Jack

    1994-01-01

    The experimental approach presented here offers a nonintrusive, qualitative and quantitative evaluation of full field flow patterns applicable in various geometries in a variety of fluids. This Full Flow Field Tracking (FFFT) Particle Image Velocimetry (PIV) technique, by means of particle tracers illuminated by a laser light sheet, offers an alternative to Laser Doppler Velocimetry (LDV), and intrusive systems such as Hot Wire/Film Anemometry. The method makes obtainable the flow patterns, and allows quantitative determination of the velocities, accelerations, and mass flows of an entire flow field. The method uses a computer based digitizing system attached through an imaging board to a low luminosity camera. A customized optical train allows the system to become a long distance microscope (LDM), allowing magnifications of areas of interest ranging up to 100 times. Presented in addition to the method itself, are studies in which the flow patterns and velocities were observed and evaluated in three distinct geometries, with three different working fluids. The first study involved pressure and flow analysis of a brush seal in oil. The next application involved studying the velocity and flow patterns in a cowl lip cooling passage of an air breathing aircraft engine using water as the working fluid. Finally, the method was extended to a study in air to examine the flows in a staggered pin arrangement located on one side of a branched duct.

  12. Holographic subsonic flow visualization.

    PubMed

    Reinheimer, C J; Wiswall, C E; Schmiege, R A; Harris, R J; Dueker, J E

    1970-09-01

    A pulsed ruby laser holographic interferometer was used to detect density gradients in the airflow around an airfoil at subsonic speeds in a low speed wind tunnel. These experiments proved that vibration of the optical components or object between exposures of the interferometric hologram does not destroy the detection of density gradients but actually can aid in the flow visualization. The density gradients determined from the fringe pattern analysis are consistent with the anticipated flow pattern.

  13. F-106 Flow Visualization

    NASA Technical Reports Server (NTRS)

    1990-01-01

    Convair F-106B Delta Dart: As the last piloted Convair F-106 anywhere, NASA 816 saw service at Langley researching storm hazards, experimenting with an Off-Surface flow visualization system and testing a vortex flap. The Delta Dart was not turned over for target drone duty as were the vast majority of F-106s, but retired to the Virginia Air & Space Center in Hampton, Virginia.

  14. FAITH Water Channel Flow Visualization

    NASA Video Gallery

    Water channel flow visualization experiments are performed on a three dimensional model of a small hill. This experiment was part of a series of measurements of the complex fluid flow around the hi...

  15. Flow, affect and visual creativity.

    PubMed

    Cseh, Genevieve M; Phillips, Louise H; Pearson, David G

    2015-01-01

    Flow (being in the zone) is purported to have positive consequences in terms of affect and performance; however, there is no empirical evidence about these links in visual creativity. Positive affect often--but inconsistently--facilitates creativity, and both may be linked to experiencing flow. This study aimed to determine relationships between these variables within visual creativity. Participants performed the creative mental synthesis task to simulate the creative process. Affect change (pre- vs. post-task) and flow were measured via questionnaires. The creativity of synthesis drawings was rated objectively and subjectively by judges. Findings empirically demonstrate that flow is related to affect improvement during visual creativity. Affect change was linked to productivity and self-rated creativity, but no other objective or subjective performance measures. Flow was unrelated to all external performance measures but was highly correlated with self-rated creativity; flow may therefore motivate perseverance towards eventual excellence rather than provide direct cognitive enhancement.

  16. Accuracy of quantitative visual soil assessment

    NASA Astrophysics Data System (ADS)

    van Leeuwen, Maricke; Heuvelink, Gerard; Stoorvogel, Jetse; Wallinga, Jakob; de Boer, Imke; van Dam, Jos; van Essen, Everhard; Moolenaar, Simon; Verhoeven, Frank; Stoof, Cathelijne

    2016-04-01

    Visual soil assessment (VSA) is a method to assess soil quality visually, when standing in the field. VSA is increasingly used by farmers, farm organisations and companies, because it is rapid and cost-effective, and because looking at soil provides understanding about soil functioning. Often VSA is regarded as subjective, so there is a need to verify VSA. Also, many VSAs have not been fine-tuned for contrasting soil types. This could lead to wrong interpretation of soil quality and soil functioning when contrasting sites are compared to each other. We wanted to assess accuracy of VSA, while taking into account soil type. The first objective was to test whether quantitative visual field observations, which form the basis in many VSAs, could be validated with standardized field or laboratory measurements. The second objective was to assess whether quantitative visual field observations are reproducible, when used by observers with contrasting backgrounds. For the validation study, we made quantitative visual observations at 26 cattle farms. Farms were located at sand, clay and peat soils in the North Friesian Woodlands, the Netherlands. Quantitative visual observations evaluated were grass cover, number of biopores, number of roots, soil colour, soil structure, number of earthworms, number of gley mottles and soil compaction. Linear regression analysis showed that four out of eight quantitative visual observations could be well validated with standardized field or laboratory measurements. The following quantitative visual observations correlated well with standardized field or laboratory measurements: grass cover with classified images of surface cover; number of roots with root dry weight; amount of large structure elements with mean weight diameter; and soil colour with soil organic matter content. Correlation coefficients were greater than 0.3, from which half of the correlations were significant. For the reproducibility study, a group of 9 soil scientists and 7

  17. Flow visualization around axial flow fan blades

    NASA Astrophysics Data System (ADS)

    Kawaguchi, K.; Matsui, K.

    1986-02-01

    The flow around the blades of an axial flow fan was visualized by using a drum camera. The distribution of the flow velocity about the blades was determined by combining the spark tracing method with the smoke wire method, making it possible to determine the blade element efficiency. The efficiencies and noise levels of radiator cooling fans can be determined using this technique. The method was applied to two types of fans with different performances, and the flow around the wing was correlated with the wing tip efficiency. The effect of tip vortex on the total fan noise was quantified.

  18. Surface-Streamline Flow Visualization

    NASA Technical Reports Server (NTRS)

    Langston, L.; Boyle, M.

    1985-01-01

    Matrix of ink dots covers matte surface of polyester drafting film. Film placed against wind-tunnel wall. Layer of methyl salicylate (oil of wintergreen) sprayed over dotted area. Ink dot streaklines show several characteristics of flow, including primary saddle point of separations, primary horseshoe vortex and smaller vortex at cylinder/ endwall junction. Surface streamline flow visualization technique suitable for use in low-speed windtunnels or other low-speed gas flows.

  19. NASA Dryden flow visualization facility

    NASA Technical Reports Server (NTRS)

    Delfrate, John H.

    1995-01-01

    This report describes the Flow Visualization Facility at NASA Dryden Flight Research Center, Edwards, California. This water tunnel facility is used primarily for visualizing and analyzing vortical flows on aircraft models and other shapes at high-incidence angles. The tunnel is used extensively as a low-cost, diagnostic tool to help engineers understand complex flows over aircraft and other full-scale vehicles. The facility consists primarily of a closed-circuit water tunnel with a 16- x 24-in. vertical test section. Velocity of the flow through the test section can be varied from 0 to 10 in/sec; however, 3 in/sec provides optimum velocity for the majority of flow visualization applications. This velocity corresponds to a unit Reynolds number of 23,000/ft and a turbulence level over the majority of the test section below 0.5 percent. Flow visualization techniques described here include the dye tracer, laser light sheet, and shadowgraph. Limited correlation to full-scale flight data is shown.

  20. A collection of flow visualization techniques used in the Aerodynamic Research Branch

    NASA Technical Reports Server (NTRS)

    1984-01-01

    Theoretical and experimental research on unsteady aerodynamic flows is discussed. Complex flow fields that involve separations, vortex interactions, and transonic flow effects were investigated. Flow visualization techniques are used to obtain a global picture of the flow phenomena before detailed quantitative studies are undertaken. A wide variety of methods are used to visualize fluid flow and a sampling of these methods is presented. It is emphasized that the visualization technique is a thorough quantitative analysis and subsequent physical understanding of these flow fields.

  1. Straightening tubular flow for side-by-side visualization.

    PubMed

    Angelelli, Paolo; Hauser, Helwig

    2011-12-01

    Flows through tubular structures are common in many fields, including blood flow in medicine and tubular fluid flows in engineering. The analysis of such flows is often done with a strong reference to the main flow direction along the tubular boundary. In this paper we present an approach for straightening the visualization of tubular flow. By aligning the main reference direction of the flow, i.e., the center line of the bounding tubular structure, with one axis of the screen, we are able to natively juxtapose (1.) different visualizations of the same flow, either utilizing different flow visualization techniques, or by varying parameters of a chosen approach such as the choice of seeding locations for integration-based flow visualization, (2.) the different time steps of a time-dependent flow, (3.) different projections around the center line , and (4.) quantitative flow visualizations in immediate spatial relation to the more qualitative classical flow visualization. We describe how to utilize this approach for an informative interactive visual analysis. We demonstrate the potential of our approach by visualizing two datasets from two different fields: an arterial blood flow measurement and a tubular gas flow simulation from the automotive industry. PMID:22034324

  2. Flow visualization using moving textures

    SciTech Connect

    Max, N.; Becker, B.

    1995-04-01

    An intuitive way to visualize a flow is to watch particles or textures move in the flow. In this paper, the authors show how texture mapping hardware can produce near-real-time texture motion, using a polygon grid, and one fixed texture. However, the authors make no attempt to indicate the flow direction in a still frame. As discussed here, any anisotropic stretching comes from the velocity gradient, not the velocity itself. The basic idea is to advect the texture by the flow field. In a cited paper, they gave an indication of the wind velocity by advecting the 3D texture coordinates on the polygon vertices of a cloudiness contour surface in a climate simulation. This was slow, because the 3D texture was rendered in software, and because advecting the texture was difficult for time-varying flows. In this paper, they replace the 3D textures by 2D texture maps compatible with hardware rendering, and give techniques for handling time-varying flows more efficiently. The next section gives their technique for the case of 2D steady flows, and the following one discusses the problems of texture distortion. Then they discuss the problems with extending method to time-varying flows, and two solutions. Next they develop compositing methods for visualizing 3D flows. The final section gives their results and conclusions.

  3. Surface flow visualization using indicators

    NASA Technical Reports Server (NTRS)

    Crowder, J. P.

    1982-01-01

    Surface flow visualization using indicators in the cryogenic wind tunnel which requires a fresh look at materials and procedures to accommodate the new test conditions is described. Potential liquid and gaseous indicators are identified. The particular materials illustrate the various requirements an indicator must fulfill. The indicator must respond properly to the flow phenomenon of interest and must be observable. Boundary layer transition is the most important phenomenon for which flow visualization indicators may be employed. The visibility of a particular indicator depends on utilizing various optical or chemical reactions. Gaseous indicators are more difficult to utilize, but because of their diversity may present unusual and useful opportunities. Factors to be considered in selecting an indicator include handling safety, toxicity, potential for contamination of the tunnel, and cost.

  4. Surface indicator and smoke flow visualization techniques in rotating machinery

    NASA Astrophysics Data System (ADS)

    Joslyn, H. David; Dring, Robert P.

    The surface indicator (ammonia/Ozalid paper) flow visualization technique for turbomachine flow research is presently noted to be especially valuable in the specification of instrumentation arrays in film cooling studies. This method is also useful in interpreting quantitative aerodynamic measurements and in detecting the presence of such three-dimensional phenomena as relative eddies, end-wall secondary flows, tip leakage flows, corner stalls, boundary layer transition and separation, and radial fluid transport. The smoke flow visualization technique can lead to a better understanding of wake-airfoil interaction, thereby furnishing a basis for the assessment of analytical models.

  5. High speed digital holographic interferometry for hypersonic flow visualization

    NASA Astrophysics Data System (ADS)

    Hegde, G. M.; Jagdeesh, G.; Reddy, K. P. J.

    2013-06-01

    Optical imaging techniques have played a major role in understanding the flow dynamics of varieties of fluid flows, particularly in the study of hypersonic flows. Schlieren and shadowgraph techniques have been the flow diagnostic tools for the investigation of compressible flows since more than a century. However these techniques provide only the qualitative information about the flow field. Other optical techniques such as holographic interferometry and laser induced fluorescence (LIF) have been used extensively for extracting quantitative information about the high speed flows. In this paper we present the application of digital holographic interferometry (DHI) technique integrated with short duration hypersonic shock tunnel facility having 1 ms test time, for quantitative flow visualization. Dynamics of the flow fields in hypersonic/supersonic speeds around different test models is visualized with DHI using a high-speed digital camera (0.2 million fps). These visualization results are compared with schlieren visualization and CFD simulation results. Fringe analysis is carried out to estimate the density of the flow field.

  6. Flow Visualization Techniques for Flight Research

    NASA Technical Reports Server (NTRS)

    Fisher, David F.; Meyer, Robert R., Jr.

    1988-01-01

    In-flight flow visualization techniques used at the Dryden Flight Research Facility of NASA Ames Research Center (Ames-Dryden) and its predecessor organizations are described. Results from flight tests which visualized surface flows using flow cones, tufts, oil flows, liquid crystals, sublimating chemicals, and emitted fluids have been obtained. Off-surface flow visualization of vortical flow has been obtained from natural condensation and two methods using smoke generator systems. Recent results from flight tests at NASA Langley Research Center using a propylene glycol smoker and an infrared imager are also included. Results from photo-chase aircraft, onboard and postflight photography are presented.

  7. Software Aids Visualization of Computed Unsteady Flow

    NASA Technical Reports Server (NTRS)

    Kao, David; Kenwright, David

    2003-01-01

    Unsteady Flow Analysis Toolkit (UFAT) is a computer program that synthesizes motions of time-dependent flows represented by very large sets of data generated in computational fluid dynamics simulations. Prior to the development of UFAT, it was necessary to rely on static, single-snapshot depictions of time-dependent flows generated by flow-visualization software designed for steady flows. Whereas it typically takes weeks to analyze the results of a largescale unsteady-flow simulation by use of steady-flow visualization software, the analysis time is reduced to hours when UFAT is used. UFAT can be used to generate graphical objects of flow visualization results using multi-block curvilinear grids in the format of a previously developed NASA data-visualization program, PLOT3D. These graphical objects can be rendered using FAST, another popular flow visualization software developed at NASA. Flow-visualization techniques that can be exploited by use of UFAT include time-dependent tracking of particles, detection of vortex cores, extractions of stream ribbons and surfaces, and tetrahedral decomposition for optimal particle tracking. Unique computational features of UFAT include capabilities for automatic (batch) processing, restart, memory mapping, and parallel processing. These capabilities significantly reduce analysis time and storage requirements, relative to those of prior flow-visualization software. UFAT can be executed on a variety of supercomputers.

  8. Visualizing quantitative microscopy data: History and challenges

    PubMed Central

    Sailem, Heba Z.; Cooper, Sam; Bakal, Chris

    2016-01-01

    Abstract Data visualization is a fundamental aspect of science. In the context of microscopy-based studies, visualization typically involves presentation of the images themselves. However, data visualization is challenging when microscopy experiments entail imaging of millions of cells, and complex cellular phenotypes are quantified in a high-content manner. Most well-established visualization tools are inappropriate for displaying high-content data, which has driven the development of new visualization methodology. In this review, we discuss how data has been visualized in both classical and high-content microscopy studies; as well as the advantages, and disadvantages, of different visualization methods. PMID:26906253

  9. Quantitative Functional Morphology by Imaging Flow Cytometry.

    PubMed

    Vorobjev, Ivan A; Barteneva, Natasha S

    2016-01-01

    This chapter describes advantages and limitations of imaging flow cytometry (IFC) based on Imagestream instrumentation using a hybrid approach of morphometric measurement and quantitation of multiparametric fluorescent intensities' distribution in cells and particles. Brief comparison is given of IFC with conventional flow cytometry and fluorescent microscopy. Some future directions of the IFC technology are described and discussed. PMID:27460234

  10. Quantitative Functional Morphology by Imaging Flow Cytometry.

    PubMed

    Vorobjev, Ivan A; Barteneva, Natasha S

    2016-01-01

    This chapter describes advantages and limitations of imaging flow cytometry (IFC) based on Imagestream instrumentation using a hybrid approach of morphometric measurement and quantitation of multiparametric fluorescent intensities' distribution in cells and particles. Brief comparison is given of IFC with conventional flow cytometry and fluorescent microscopy. Some future directions of the IFC technology are described and discussed.

  11. Centrifuge in space fluid flow visualization experiment

    NASA Technical Reports Server (NTRS)

    Arnold, William A.; Wilcox, William R.; Regel, Liya L.; Dunbar, Bonnie J.

    1993-01-01

    A prototype flow visualization system is constructed to examine buoyancy driven flows during centrifugation in space. An axial density gradient is formed by imposing a thermal gradient between the two ends of the test cell. Numerical computations for this geometry showed that the Prandtl number plays a limited part in determining the flow.

  12. Visualizing vector field topology in fluid flows

    NASA Technical Reports Server (NTRS)

    Helman, James L.; Hesselink, Lambertus

    1991-01-01

    Methods of automating the analysis and display of vector field topology in general and flow topology in particular are discussed. Two-dimensional vector field topology is reviewed as the basis for the examination of topology in three-dimensional separated flows. The use of tangent surfaces and clipping in visualizing vector field topology in fluid flows is addressed.

  13. A new quantitative indicator of visual fatigue

    NASA Technical Reports Server (NTRS)

    Goussard, Yves; Martin, Bernard; Stark, Lawrence

    1987-01-01

    Ocular-motor correlates of visual fatigue have remained elusive. Performance of ocular-motor tracking with a wide-band white noise input and the response of the dual-mode, smooth pursuit-saccadic eye movement system as output was used to test visual fatigue. A new visual fatigue indicator, VFI, was defined as the nonlinear remnant after subtracting an identified impulse response contribution to the output. Subjects were required to perform very fatiguing CRT screen reading tasks, and the VFI correlated well with the subjective reports of visual fatigue.

  14. Flow visualization of helicopter blade tip vortices - A quantitative technique to determine the trajectory and the position of the tip vortex pattern of a model rotor

    NASA Astrophysics Data System (ADS)

    Mercker, E.; Pengel, Kurt

    1992-09-01

    A visualization has been conducted of the tip vortex pattern of a descending model helicopter rotor, using a system that employs a continuous single-laser light sheet, a triggerable fast-motion video camera, a powerful strobe-light, and an oil smoke generator. The laser light sheet can be cast in any desired cross-section perpendicular to the plane by means of a two-degree-of-freedom traverse system. A reference grid was placed in the plane of the light sheet after the rotor and airstream were stopped, in order to quantify the distance between a given blade and the corresponding tip vortices.

  15. Quantitative and comparative visualization applied to cosmological simulations

    NASA Astrophysics Data System (ADS)

    Ahrens, James; Heitmann, Katrin; Habib, Salman; Ankeny, Lee; McCormick, Patrick; Inman, Jeff; Armstrong, Ryan; Ma, Kwan-Liu

    2006-09-01

    Cosmological simulations follow the formation of nonlinear structure in dark and luminous matter. The associated simulation volumes and dynamic range are very large, making visualization both a necessary and challenging aspect of the analysis of these datasets. Our goal is to understand sources of inconsistency between different simulation codes that are started from the same initial conditions. Quantitative visualization supports the definition and reasoning about analytically defined features of interest. Comparative visualization supports the ability to visually study, side by side, multiple related visualizations of these simulations. For instance, a scientist can visually distinguish that there are fewer halos (localized lumps of tracer particles) in low-density regions for one simulation code out of a collection. This qualitative result will enable the scientist to develop a hypothesis, such as loss of halos in low-density regions due to limited resolution, to explain the inconsistency between the different simulations. Quantitative support then allows one to confirm or reject the hypothesis. If the hypothesis is rejected, this step may lead to new insights and a new hypothesis, not available from the purely qualitative analysis. We will present methods to significantly improve the Scientific analysis process by incorporating quantitative analysis as the driver for visualization. Aspects of this work are included as part of two visualization tools, ParaView, an open-source large data visualization tool, and Scout, an analysis-language based, hardware-accelerated visualization tool.

  16. A nonintrusive method of quantifying flow visualization data in vortex flow fields

    NASA Astrophysics Data System (ADS)

    Sei, Vincent J.

    1994-12-01

    The High Angle of Attack Research Vehicle (HARV) as well as other similar flight test aircraft have been using smoke flow visualization techniques to characterize the vortex flow created by leading edge extensions and the forebody. With the advent of video measurement techniques, this type of flow visualization can not only provide a qualitative assessment of the flow but also a quantitative measure to be used to validate computational fluid dynamic codes and wind tunnel test. One of the major drawbacks to employing video imaging was the introduction of false motion due to camera movement in flight. A relative motion approach using fixed targets along with the flow visualization scheme was utilized to remove unwanted motion. The relative motion algorithm was tested using a laboratory test setup where cameras underwent both translational and rotational motion to simulate both wing bending and torsion. The method was effective in removing both motions with only a slight loss of accuracy.

  17. Holographic flow visualization in rotating turbomachinery

    NASA Astrophysics Data System (ADS)

    Parker, R. J.; Reeves, M.

    1990-11-01

    Holographic flow visualization has found many applications in rotating turbomachinery. Applications in the design of aeroengine fans, automotive turbochargers, turbines, helicopter rotors, and advanced propfans are discussed. Work in ducted rotating flows and rotating free aerofoils is brought together and new developments in each field are revealed.

  18. Flow volumes for interactive vector field visualization

    SciTech Connect

    Max, N.; Becker, B.; Crawfis, R.

    1993-04-06

    Flow volumes are the volumetric equivalent of stream lines. They provide more information about the vector field being visualized than do stream lines or ribbons. Presented is an efficient method for producing flow volumes, composed of transparently rendered tetrahedra, for use in an interactive system. The problems of rendering, subdivision, sorting, rendering artifacts, and user interaction are dealt with.

  19. Water tunnel flow visualization using a laser

    NASA Technical Reports Server (NTRS)

    Beckner, C.; Curry, R. E.

    1985-01-01

    Laser systems for flow visualization in water tunnels (similar to the vapor screen technique used in wind tunnels) can provide two-dimensional cross-sectional views of complex flow fields. This parametric study documents the practical application of the laser-enhanced visualization (LEV) technique to water tunnel testing. Aspects of the study include laser power levels, flow seeding (using flourescent dyes and embedded particulates), model preparation, and photographic techniques. The results of this study are discussed to provide potential users with basic information to aid in the design and setup of an LEV system.

  20. Application of photogrammetry to surface flow visualization

    NASA Astrophysics Data System (ADS)

    Karthikeyan, N.; Venkatakrishnan, L.

    2011-03-01

    The construction of three-dimensional surface flow fields is an extremely difficult task owing largely to the fragmented information available in the form of 2D images. Here, the method of photogrammetric resection based on a comprehensive camera model has been used to map oil flow visualization images on to the surface grid of the model. The data exported in the VRML format allow for user interaction in a manner not possible with 2D images. The technique is demonstrated here using the surface oil flow visualization images of a simplified landing gear model at low speed in a conventional wind tunnel without any specialized rigs for photogrammetry. The results are not limited to low-speed regimes and show that this technique can have significant impact on understanding the flow physics associated with the surface flow topology of highly three-dimensional separated flows on complex models.

  1. Quantitative tomographic measurements of opaque multiphase flows

    SciTech Connect

    GEORGE,DARIN L.; TORCZYNSKI,JOHN R.; SHOLLENBERGER,KIM ANN; O'HERN,TIMOTHY J.; CECCIO,STEVEN L.

    2000-03-01

    An electrical-impedance tomography (EIT) system has been developed for quantitative measurements of radial phase distribution profiles in two-phase and three-phase vertical column flows. The EIT system is described along with the computer algorithm used for reconstructing phase volume fraction profiles. EIT measurements were validated by comparison with a gamma-densitometry tomography (GDT) system. The EIT system was used to accurately measure average solid volume fractions up to 0.05 in solid-liquid flows, and radial gas volume fraction profiles in gas-liquid flows with gas volume fractions up to 0.15. In both flows, average phase volume fractions and radial volume fraction profiles from GDT and EIT were in good agreement. A minor modification to the formula used to relate conductivity data to phase volume fractions was found to improve agreement between the methods. GDT and EIT were then applied together to simultaneously measure the solid, liquid, and gas radial distributions within several vertical three-phase flows. For average solid volume fractions up to 0.30, the gas distribution for each gas flow rate was approximately independent of the amount of solids in the column. Measurements made with this EIT system demonstrate that EIT may be used successfully for noninvasive, quantitative measurements of dispersed multiphase flows.

  2. Visualization, Selection, and Analysis of Traffic Flows.

    PubMed

    Scheepens, Roeland; Hurter, Christophe; van de Wetering, Huub; van Wijk, Jarke J

    2016-01-01

    Visualization of the trajectories of moving objects leads to dense and cluttered images, which hinders exploration and understanding. It also hinders adding additional visual information, such as direction, and makes it difficult to interactively extract traffic flows, i.e., subsets of trajectories. In this paper we present our approach to visualize traffic flows and provide interaction tools to support their exploration. We show an overview of the traffic using a density map. The directions of traffic flows are visualized using a particle system on top of the density map. The user can extract traffic flows using a novel selection widget that allows for the intuitive selection of an area, and filtering on a range of directions and any additional attributes. Using simple, visual set expressions, the user can construct more complicated selections. The dynamic behaviors of selected flows may then be shown in annotation windows in which they can be interactively explored and compared. We validate our approach through use cases where we explore and analyze the temporal behavior of aircraft and vessel trajectories, e.g., landing and takeoff sequences, or the evolution of flight route density. The aircraft use cases have been developed and validated in collaboration with domain experts.

  3. Visualization, Selection, and Analysis of Traffic Flows.

    PubMed

    Scheepens, Roeland; Hurter, Christophe; van de Wetering, Huub; van Wijk, Jarke J

    2016-01-01

    Visualization of the trajectories of moving objects leads to dense and cluttered images, which hinders exploration and understanding. It also hinders adding additional visual information, such as direction, and makes it difficult to interactively extract traffic flows, i.e., subsets of trajectories. In this paper we present our approach to visualize traffic flows and provide interaction tools to support their exploration. We show an overview of the traffic using a density map. The directions of traffic flows are visualized using a particle system on top of the density map. The user can extract traffic flows using a novel selection widget that allows for the intuitive selection of an area, and filtering on a range of directions and any additional attributes. Using simple, visual set expressions, the user can construct more complicated selections. The dynamic behaviors of selected flows may then be shown in annotation windows in which they can be interactively explored and compared. We validate our approach through use cases where we explore and analyze the temporal behavior of aircraft and vessel trajectories, e.g., landing and takeoff sequences, or the evolution of flight route density. The aircraft use cases have been developed and validated in collaboration with domain experts. PMID:26390467

  4. Flow field visualization about external axial corners

    NASA Technical Reports Server (NTRS)

    Talcott, N. A., Jr.

    1978-01-01

    An experimental investigation was conducted to visualize the flow field about external axial corners. The investigation was initiated to provide answers to questions about the inviscid flow pattern for continuing numerical investigations. Symmetrical and asymmetrical corner models were tested at a Reynolds number per meter of 60,700,000. Oil-flow and vapor-screen photographs were taken for both models at angle of attack and yaw. The paper presents the results of the investigation in the form of oil-flow photographs and the surrounding shock wave location obtained from the vapor screens.

  5. Graphics and Flow Visualization of Computer Generated Flow Fields

    NASA Technical Reports Server (NTRS)

    Kathong, M.; Tiwari, S. N.

    1987-01-01

    Flow field variables are visualized using color representations described on surfaces that are interpolated from computational grids and transformed to digital images. Techniques for displaying two and three dimensional flow field solutions are addressed. The transformations and the use of an interactive graphics program for CFD flow field solutions, called PLOT3D, which runs on the color graphics IRIS workstation are described. An overview of the IRIS workstation is also described.

  6. Transonic flow visualization using holographic interferometry

    NASA Technical Reports Server (NTRS)

    Bryanston-Cross, Peter J.

    1987-01-01

    An account is made of some of the applications of holographic interferometry to the visualization of transonic flows. In the case of the compressor shock visualization, the method is used regularly and has moved from being a research department invention to a design test tool. With the implementation of automatic processing and simple digitization systems, holographic vibrational analysis has also moved into routine nondestructive testing. The code verification interferograms were instructive, but the main turbomachinery interest is now in 3 dimensional flows. A major data interpretation effort will be required to compute tomographically the 3 dimensional flow around the leading or the trailing edges of a rotating blade row. The bolt on approach shows the potential application to current unsteady flows of interest. In particular that of the rotor passing and vortex interaction effects is experienced by the new generation of unducted fans. The turbocharger tests presents a new area for the application of holography.

  7. Holographic Flow Visualization at NASA Langley

    NASA Technical Reports Server (NTRS)

    Burner, A. W.; Goad, W. K.

    2005-01-01

    Holographic flow visualization systems at two NASA Langley facilities, a hypersonic blow-down tunnel using CF4 gas and an expansion tube with very short test time, are described. A pulsed ruby laser is used at a CF4 tunnel for single pulse holography, double pulse with several minutes between exposures, and dual plate holographic interferometry. Shadow-graph, schlieren, and interferograms are reconstructed from the holograms in a separate reconstruction lab. At the expansion tube the short run time of 200 microseconds requires precise triggering of its double pulsed ruby laser. With pulse separation, one pulse can occur before and one after flow is established to obtain fringe free background interferograms (perfect infinite fringe) or both pulses can occur during flow in order to study flow instabilities. Holograms are reconstructed at the expansion tube with an in-place setup which makes use of a high power CW Argon laser and common optics for both recording and reconstructing the holograms. The holographic systems at the CF4 tunnel and expansion tube are operated routinely for flow visualization by tunnel technicians. Typical flow visualization photographs from both facilities are presented.

  8. Holographic flow visualization at NASA Langley

    NASA Technical Reports Server (NTRS)

    Burner, A. W.; Goad, W. K.

    1979-01-01

    Holographic flow visualization systems at two NASA Langley facilities, a hypersonic blow-down tunnel using CF4 gas and an expansion tube with very short test time, are described. A pulsed ruby laser is used at a CF4 tunnel for single pulse holography, double pulse with several minutes between exposures, and dual plate holographic interferometry. Shadowgraph, schlieren, and interferograms are reconstructed from the holograms in a separate reconstruction lab. At the expansion tube the short run time of 200 microseconds requires precise triggering of its double pulsed ruby laser. With double pulse capability of 20 to 1200 microseconds pulse separation, one pulse can occur before and one later after flow is established to obtain fringe free background interferograms (perfect infinite fringe) or both pulses can occur during flow in order to study flow instabilities. Holograms are reconstructed at the expansion tube with an in-place setup which makes use of a high power CW Argon laser and common optics for both recording and reconstructing the holograms. The holographic systems at the CF4 tunnel and expansion tube are operated routinely for flow visualization by tunnel technicians. Typical flow visualization photographs from both facilities are presented.

  9. B-1 AFT Nacelle Flow Visualization Study

    NASA Technical Reports Server (NTRS)

    Celniker, Robert

    1975-01-01

    A 2-month program was conducted to perform engineering evaluation and design tasks to prepare for visualization and photography of the airflow along the aft portion of the B-1 nacelles and nozzles during flight test. Several methods of visualizing the flow were investigated and compared with respect to cost, impact of the device on the flow patterns, suitability for use in the flight environment, and operability throughout the flight. Data were based on a literature search and discussions with the test personnel. Tufts were selected as the flow visualization device in preference to several other devices studied. A tuft installation pattern has been prepared for the right-hand aft nacelle area of B-1 air vehicle No.2. Flight research programs to develop flow visualization devices other than tufts for use in future testing are recommended. A design study was conducted to select a suitable motion picture camera, to select the camera location, and to prepare engineering drawings sufficient to permit installation of the camera. Ten locations on the air vehicle were evaluated before the selection of the location in the horizontal stabilizer actuator fairing. The considerations included cost, camera angle, available volume, environmental control, flutter impact, and interference with antennas or other instrumentation.

  10. Fluorescent particles enable visualization of gas flow

    NASA Technical Reports Server (NTRS)

    Wilson, A. J.

    1968-01-01

    Fluorescent particles enable visualization of the flow patterns of gases at slow velocities. Through a transparent section in the gas line, a camera views the visible light emitted by the particles carried by the gas stream. Fine definition of the particle tracks are obtained at slow camera shutter speeds.

  11. Visualizing Flow of Uncertainty through Analytical Processes.

    PubMed

    Wu, Yingcai; Yuan, Guo-Xun; Ma, Kwan-Liu

    2012-12-01

    Uncertainty can arise in any stage of a visual analytics process, especially in data-intensive applications with a sequence of data transformations. Additionally, throughout the process of multidimensional, multivariate data analysis, uncertainty due to data transformation and integration may split, merge, increase, or decrease. This dynamic characteristic along with other features of uncertainty pose a great challenge to effective uncertainty-aware visualization. This paper presents a new framework for modeling uncertainty and characterizing the evolution of the uncertainty information through analytical processes. Based on the framework, we have designed a visual metaphor called uncertainty flow to visually and intuitively summarize how uncertainty information propagates over the whole analysis pipeline. Our system allows analysts to interact with and analyze the uncertainty information at different levels of detail. Three experiments were conducted to demonstrate the effectiveness and intuitiveness of our design.

  12. Visualization of the flow past a frisbee

    NASA Astrophysics Data System (ADS)

    Nakamura, Y.; Fukamachi, N.

    1991-01-01

    The flow past a Frisbee is visualized in a low-speed wind tunnel using smoke to identify the mechanism of lift generation in forward flight. It is found that as the air flow passes over a Frisbee, a pair of longitudinal vortices is formed just behind it. The vortex pair induces substantial downwash in the downstream flow, and as a result, a lift force can act on a Frisbee. The rotation of a Frisbee greatly strengthens the vortex pair, thereby enhancing the downwash and hence the lift force.

  13. Improved visualization of flow field measurements

    NASA Technical Reports Server (NTRS)

    Miles, Jeffrey Hilton

    1991-01-01

    A capability is proposed that makes it feasible to apply to measured flow field data the visualization tools developed to display numerical solutions for computational fluid dynamic problems. The measurement monitor surface (MMS) methodology was used for the analysis of flow field measurements within a low-aspect-ratio transonic axial-flow fan rotor acquired with two-dimensional laser anemometry. It is shown that the MMS method may be utilized to generate input for the multidimensional processing and analytical tools developed for numerical flow field simulation data. Thus an experimenter utilizing an interactive graphics program could illustrate scalar quantities such as Mach number by profiles, contour lines, carpet plots, and surfaces employing various color intensities. Also, flow directionality can be shown by the display of vector fields and particle traces.

  14. Flow visualization of CFD using graphics workstations

    NASA Technical Reports Server (NTRS)

    Lasinski, Thomas; Buning, Pieter; Choi, Diana; Rogers, Stuart; Bancroft, Gordon

    1987-01-01

    High performance graphics workstations are used to visualize the fluid flow dynamics obtained from supercomputer solutions of computational fluid dynamic programs. The visualizations can be done independently on the workstation or while the workstation is connected to the supercomputer in a distributed computing mode. In the distributed mode, the supercomputer interactively performs the computationally intensive graphics rendering tasks while the workstation performs the viewing tasks. A major advantage of the workstations is that the viewers can interactively change their viewing position while watching the dynamics of the flow fields. An overview of the computer hardware and software required to create these displays is presented. For complex scenes the workstation cannot create the displays fast enough for good motion analysis. For these cases, the animation sequences are recorded on video tape or 16 mm film a frame at a time and played back at the desired speed. The additional software and hardware required to create these video tapes or 16 mm movies are also described. Photographs illustrating current visualization techniques are discussed. Examples of the use of the workstations for flow visualization through animation are available on video tape.

  15. Basic flow structure in saccular aneurysms: a flow visualization study.

    PubMed

    Steiger, H J; Poll, A; Liepsch, D; Reulen, H J

    1987-01-01

    Basic flow patterns were investigated in a set of glass aneurysm models by means of flow visualization methods. Dye injection and streaming double refraction were used to visualize flow. The circulation inside lateral aneurysms arising at a 90 degree angle from a straight parent conduit could not be visualized by the dye-injection technique but could be demonstrated by streaming double refraction. The inflow was seen to arise from the downstream lip of the orifice and to project to the dome of the aneurysm. Backflow to the parent conduit took place along the walls of the aneurysm. In aneurysms located at bifurcations, flow characteristics depended on the geometry of the bifurcation and the flow ratio between the branches. Relatively little intra-aneurysmal flow was demonstrated in side branch-related aneurysms arising distal to an asymmetric 90 degrees bifurcation of the type encountered at the junction of the internal carotid and posterior communicating arteries. Stagnation of flow at the neck and little intra-aneurysmal circulation were found with terminal aneurysms of the basilar bifurcation type if the outflow through the branches was symmetric. With asymmetric outflow, however, or if the axis of the aneurysm did not coincide with that of the afferent vessel, an active rotation developed in these aneurysms. The size of the aneurysm had no influence on the basic pattern of intra-aneurysmal circulation. The use of pulsatile perfusion did not significantly alter the basic flow patterns observed with steady flow. Locally disturbed laminar flow was observed in certain models at physiological Reynold's numbers, but there were no signs of fully developed turbulence.

  16. Flow cytometric determination of quantitative immunophenotypes

    NASA Astrophysics Data System (ADS)

    Redelman, Douglas; Ensign, Wayne; Roberts, Don

    2001-05-01

    Immunofluorescent flow cytometric analysis of peripheral blood leucocytes is most commonly used to identify and enumerate cells defined by one or more clusters of differentiation (CD) antigens. Although less widely employed, quantitative tests that measure the amounts of CD antigens expressed per cell are used in some situations such as the characterization of lymphomas and leukocytes or the measurement of CD38 on CD3plu8pluT cells in HIV infected individuals. The CD antigens used to identify leukocyte populations are functionally important molecules and it is known that under- or over-expression of some CD antigens can affect cellular responses. For example, high or low expression of CD19 on B cells is associated with autoimmune conditions or depressed antibody responses, respectively. In the current studies, the quantitative expression of CD antigens on T cells, B cells and monocytes was determined in a group of age and sex-matched Marines at several times before and after training exercises. There was substantial variation among these individuals in the quantitative expression of CD antigens and in the number of cells in various populations. However, there was relatively little variation within individuals during the two months they were examined. Thus, the number of cells in leukocyte sub-populations and the amount of CD antigens expressed per cell appear to comprise a characteristic quantitative immunophenotype.

  17. Hydraulic flow visualization method and apparatus

    DOEpatents

    Karidis, P.G.

    1984-01-01

    An apparatus and method for visualizing liquid flow. Pulses of gas bubbles are introduced into a liquid flow stream and a strobe light is operated at a frequency related to the frequency of the gas pulses to shine on the bubbles as they pass through the liquid stream. The gas pulses pass through a probe body having a valve element, and a reciprocating valve stem passes through the probe body to operate the valve element. A stem actuating device comprises a slidable reciprocating member, operated by a crank arm. The actuated member is adjustable to adjust the amount of the valve opening during each pulse.

  18. A vapor generator for transonic flow visualization

    NASA Technical Reports Server (NTRS)

    Bruce, Robert A.; Hess, Robert W.; Rivera, Jose A., Jr.

    1989-01-01

    A vapor generator was developed for use in the NASA Langley Transonic Dynamics Tunnel (TDT). Propylene glycol was used as the vapor material. The vapor generator system was evaluated in a laboratory setting and then used in the TDT as part of a laser light sheet flow visualization system. The vapor generator provided satisfactory seeding of the air flow with visible condensate particles, smoke, for tests ranging from low subsonic through transonic speeds for tunnel total pressures from atmospheric pressure down to less than 0.1 atmospheric pressure.

  19. Improved visualization of flow field measurements

    NASA Technical Reports Server (NTRS)

    Miles, Jeffrey Hilton

    1991-01-01

    A capability was developed that makes it possible to apply to measured flow field data the visualization tools developed to display numerical solutions for computational fluid dynamic problems. The measurement monitor surface (MMS) procedure was applied to the analysis of flow field measurements within a low aspect ratio transonic axial flow fan rotor obtained with 2-D laser anemometry. The procedure generates input for the visualization tools developed to display numerical solutions for computational fluid dynamics problems. The relative Mach number contour plots obtained by this method resemble the conventional contour plots obtained by more traditional methods. The results show that the MMS procedure can be used to generate input for the multidimensional processing and analysis tools developed for data from numerical flow field simulations. They show that an experimenter can apply the MMS procedure to his data and then use an interactive graphics program to display scalar quantities like the Mach number by profiles, carpet plots, contour lines, and surfaces using various colors. Also, flow directionality can be shown by display of vector fields and particle traces.

  20. The art and science of flow control - case studies using flow visualization methods

    NASA Astrophysics Data System (ADS)

    Alvi, F. S.; Cattafesta, L. N., III

    2010-04-01

    Active flow control (AFC) has been the focus of significant research in the last decade. This is mainly due to the potentially substantial benefits it affords. AFC applications range from the subsonic to the supersonic (and beyond) regime for both internal and external flows. These applications are wide and varied, such as controlling flow transition and separation over various external components of the aircraft to active management of separation and flow distortion in engine components and over turbine and compressor blades. High-speed AFC applications include control of flow oscillations in cavity flows, supersonic jet screech, impinging jets, and jet-noise control. In this paper we review some of our recent applications of AFC through a number of case studies that illustrate the typical benefits as well as limitations of present AFC methods. The case studies include subsonic and supersonic canonical flowfields such as separation control over airfoils, control of supersonic cavity flows and impinging jets. In addition, properties of zero-net mass-flux (ZNMF) actuators are also discussed as they represent one of the most widely studied actuators used for AFC. In keeping with the theme of this special issue, the flowfield properties and their response to actuation are examined through the use of various qualitative and quantitative flow visualization methods, such as smoke, shadowgraph, schlieren, planar-laser scattering, and Particle image velocimetry (PIV). The results presented here clearly illustrate the merits of using flow visualization to gain significant insight into the flow and its response to AFC.

  1. Quantitative imaging of turbulent and reacting flows

    SciTech Connect

    Paul, P.H.

    1993-12-01

    Quantitative digital imaging, using planar laser light scattering techniques is being developed for the analysis of turbulent and reacting flows. Quantitative image data, implying both a direct relation to flowfield variables as well as sufficient signal and spatial dynamic range, can be readily processed to yield two-dimensional distributions of flowfield scalars and in turn two-dimensional images of gradients and turbulence scales. Much of the development of imaging techniques to date has concentrated on understanding the requisite molecular spectroscopy and collision dynamics to be able to determine how flowfield variable information is encoded into the measured signal. From this standpoint the image is seen as a collection of single point measurements. The present effort aims at realizing necessary improvements in signal and spatial dynamic range, signal-to-noise ratio and spatial resolution in the imaging system as well as developing excitation/detection strategies which provide for a quantitative measure of particular flowfield scalars. The standard camera used for the study is an intensified CCD array operated in a conventional video format. The design of the system was based on detailed modeling of signal and image transfer properties of fast UV imaging lenses, image intensifiers and CCD detector arrays. While this system is suitable for direct scalar imaging, derived quantities (e.g. temperature or velocity images) require an exceptionally wide dynamic range imaging detector. To apply these diagnostics to reacting flows also requires a very fast shuttered camera. The authors have developed and successfully tested a new type of gated low-light level detector. This system relies on fast switching of proximity focused image-diode which is direct fiber-optic coupled to a cooled CCD array. Tests on this new detector show significant improvements in detection limit, dynamic range and spatial resolution as compared to microchannel plate intensified arrays.

  2. Dual exposure interferometry. [gas dynamics and flow visualization

    NASA Technical Reports Server (NTRS)

    Smeets, G.; George, A.

    1982-01-01

    The application of dual exposure differential interferometry to gas dynamics and flow visualization is discussed. A differential interferometer with Wallaston prisms can produce two complementary interference fringe systems, depending on the polarization of the incident light. If these two systems are superimposed on a film, with one exposure during a phenomenon, the other before or after, the phenomenon will appear on a uniform background. By regulating the interferometer to infinite fringe distance, a resolution limit of approximately lambda/500 can be obtained in the quantitative analysis of weak phase objects. This method was successfully applied to gas dynamic investigations.

  3. Flow Charts: Visualization of Vector Fields on Arbitrary Surfaces

    PubMed Central

    Li, Guo-Shi; Tricoche, Xavier; Weiskopf, Daniel; Hansen, Charles

    2009-01-01

    We introduce a novel flow visualization method called Flow Charts, which uses a texture atlas approach for the visualization of flows defined over curved surfaces. In this scheme, the surface and its associated flow are segmented into overlapping patches, which are then parameterized and packed in the texture domain. This scheme allows accurate particle advection across multiple charts in the texture domain, providing a flexible framework that supports various flow visualization techniques. The use of surface parameterization enables flow visualization techniques requiring the global view of the surface over long time spans, such as Unsteady Flow LIC (UFLIC), particle-based Unsteady Flow Advection Convolution (UFAC), or dye advection. It also prevents visual artifacts normally associated with view-dependent methods. Represented as textures, Flow Charts can be naturally integrated into hardware accelerated flow visualization techniques for interactive performance. PMID:18599918

  4. Qualitative flow visualization using colored lights and reflective flakes

    NASA Astrophysics Data System (ADS)

    Thoroddsen, S. T.; Bauer, J. M.

    1999-07-01

    We present a novel flow-visualization technique utilizing reflective flakes in combination with color illumination. Three differently colored columated light beams are used to illuminate the flow, each color being directed from a separate direction. In this way, the color of the light reflected from the flakes gives an indication of the local flake orientation. The flake orientation in complex three-dimensional (3-D) flow is in general a complicated function of the local velocity gradient tensor, but can be calculated if the underlying velocity field is known. This has recently been demonstrated by Gauthier et al. [Phys. Fluids. 10, 2147 (1998)] using monochome light. In complex flow fields the distribution of flakes may, however, be rearranged by the motion, thus making the local intensity of reflection depend on both orientation and flake concentration. The color is, however, immune to the local number density of flakes inside the flow, making quantitative information possible. This technique is demonstrated by visualizing the finer details of vortices in a Taylor-Couette device.

  5. CANDU in-reactor quantitative visual-based inspection techniques

    NASA Astrophysics Data System (ADS)

    Rochefort, P. A.

    2009-02-01

    This paper describes two separate visual-based inspection procedures used at CANDU nuclear power generating stations. The techniques are quantitative in nature and are delivered and operated in highly radioactive environments with access that is restrictive, and in one case is submerged. Visual-based inspections at stations are typically qualitative in nature. For example a video system will be used to search for a missing component, inspect for a broken fixture, or locate areas of excessive corrosion in a pipe. In contrast, the methods described here are used to measure characteristic component dimensions that in one case ensure ongoing safe operation of the reactor and in the other support reactor refurbishment. CANDU reactors are Pressurized Heavy Water Reactors (PHWR). The reactor vessel is a horizontal cylindrical low-pressure calandria tank approximately 6 m in diameter and length, containing heavy water as a neutron moderator. Inside the calandria, 380 horizontal fuel channels (FC) are supported at each end by integral end-shields. Each FC holds 12 fuel bundles. The heavy water primary heat transport water flows through the FC pressure tube, removing the heat from the fuel bundles and delivering it to the steam generator. The general design of the reactor governs both the type of measurements that are required and the methods to perform the measurements. The first inspection procedure is a method to remotely measure the gap between FC and other in-core horizontal components. The technique involves delivering vertically a module with a high-radiation-resistant camera and lighting into the core of a shutdown but fuelled reactor. The measurement is done using a line-of-sight technique between the components. Compensation for image perspective and viewing elevation to the measurement is required. The second inspection procedure measures flaws within the reactor's end shield FC calandria tube rolled joint area. The FC calandria tube (the outer shell of the FC) is

  6. Visualization of Flow Alternatives, Lower Missouri River

    USGS Publications Warehouse

    Jacobson, Robert B.; Heuser, Jeanne

    2002-01-01

    Background The U.S. Army Corps of Engineers (COE) 'Missouri River Master Water Control Manual' (Master Manual) review has resulted in consideration of many flow alternatives for managing the water in the river (COE, 2001; 1998a). The purpose of this report is to present flow-management alternative model results in a way that can be easily visualized and understood. This report was updated in October 2001 to focus on the specific flow-management alternatives presented by the COE in the 'Master Manual Revised Draft Environmental Impact Statement' (RDEIS; COE, 2001). The original version (February 2000) is available by clicking here. The COE, U.S. Fish and Wildlife Service (FWS), Missouri River states, and Missouri River basin tribes have been participating in discussions concerning water management of the Missouri River mainstem reservoir system (MRMRS), the Missouri River Bank Stabilization and Navigation Project, and the Kansas River reservoir system since 1986. These discussions include general input to the revision of the Master Manual as well as formal consultation under Section 7 of the Endangered Species Act. In 2000, the FWS issued a Biological Opinion that prescribed changes to reservoir management on the Missouri River that were believed to be necessary to preclude jeopardy to three endangered species, the pallid sturgeon, piping plover, and interior least tern (USFWS, 2000). The combined Missouri River system is large and complex, including many reservoirs, control structures, and free-flowing reaches extending over a broad region. The ability to assess future impacts of altered management scenarios necessarily involves complex, computational models that attempt to integrate physical, chemical, biological, and economic effects. Graphical visualization of the model output is intended to improve understanding of the differences among flow-management alternatives.

  7. Development of image processing techniques for applications in flow visualization and analysis

    NASA Technical Reports Server (NTRS)

    Disimile, Peter J.; Shoe, Bridget; Toy, Norman; Savory, Eric; Tahouri, Bahman

    1991-01-01

    A comparison between two flow visualization studies of an axi-symmetric circular jet issuing into still fluid, using two different experimental techniques, is described. In the first case laser induced fluorescence is used to visualize the flow structure, whilst smoke is utilized in the second. Quantitative information was obtained from these visualized flow regimes using two different digital imaging systems. Results are presented of the rate at which the jet expands in the downstream direction and these compare favorably with the more established data.

  8. Pulsed laser light sheet flow visualization

    NASA Astrophysics Data System (ADS)

    Soreide, D. C.; Douglas, G. D.; Brandt, W. P.

    A pulsed ruby laser was used as light source for a set of flow visualization tests involving two test situations. In both cases, the conducted investigation was concerned with the location of the tip vortex of the rotor-blade of a helicopter, giving particular attention to the position relative to the following blade. The optical system employed is considered along with the electronics system, the setup equipment, and the helicopter test. Vortex field maps are provided for the case in which the helicopter rotor vortex field phase angle equals 0 degrees and for the case in which this angle equals 90 degrees.

  9. Quantitative Estimation of Tissue Blood Flow Rate.

    PubMed

    Tozer, Gillian M; Prise, Vivien E; Cunningham, Vincent J

    2016-01-01

    The rate of blood flow through a tissue (F) is a critical parameter for assessing the functional efficiency of a blood vessel network following angiogenesis. This chapter aims to provide the principles behind the estimation of F, how F relates to other commonly used measures of tissue perfusion, and a practical approach for estimating F in laboratory animals, using small readily diffusible and metabolically inert radio-tracers. The methods described require relatively nonspecialized equipment. However, the analytical descriptions apply equally to complementary techniques involving more sophisticated noninvasive imaging.Two techniques are described for the quantitative estimation of F based on measuring the rate of tissue uptake following intravenous administration of radioactive iodo-antipyrine (or other suitable tracer). The Tissue Equilibration Technique is the classical approach and the Indicator Fractionation Technique, which is simpler to perform, is a practical alternative in many cases. The experimental procedures and analytical methods for both techniques are given, as well as guidelines for choosing the most appropriate method. PMID:27172960

  10. Synchronization trigger control system for flow visualization

    NASA Technical Reports Server (NTRS)

    Chun, K. S.

    1987-01-01

    The use of cinematography or holographic interferometry for dynamic flow visualization in an internal combustion engine requires a control device that globally synchronizes camera and light source timing at a predefined shaft encoder angle. The device is capable of 0.35 deg resolution for rotational speeds of up to 73 240 rpm. This was achieved by implementing the shaft encoder signal addressed look-up table (LUT) and appropriate latches. The developed digital signal processing technique achieves 25 nsec of high speed triggering angle detection by using direct parallel bit comparison of the shaft encoder digital code with a simulated angle reference code, instead of using angle value comparison which involves more complicated computation steps. In order to establish synchronization to an AC reference signal whose magnitude is variant with the rotating speed, a dynamic peak followup synchronization technique has been devised. This method scrutinizes the reference signal and provides the right timing within 40 nsec. Two application examples are described.

  11. Flow Visualization and Laser Velocimetry for Wind Tunnels

    NASA Technical Reports Server (NTRS)

    Hunter, W. W., Jr. (Editor); Foughner, J. T., Jr. (Editor)

    1982-01-01

    The need for flow visualization and laser velocimetry were discussed. The purpose was threefold: (1) provide a state-of-the-art overview; (2) provide a forum for industry, universities, and government agencies to address problems in developing useful and productive flow visualization and laser velocimetry measurement techniques; and (3) provide discussion of recent developments and applications of flow visualization and laser velocimetry measurement techniques and instrumentation systems for wind tunnels including the 0.3-Meter Transonic Cryogenic Tunnel.

  12. Improved Visualization of Cartilage Canals Using Quantitative Susceptibility Mapping

    PubMed Central

    Nissi, Mikko J.; Tóth, Ferenc; Wang, Luning; Carlson, Cathy S.; Ellermann, Jutta M.

    2015-01-01

    Purpose Cartilage canal vessels are critical to the normal function of epiphyseal (growth) cartilage and damage to these vessels is demonstrated or suspected in several important developmental orthopaedic diseases. High-resolution, three-dimensional (3-D) visualization of cartilage canals has recently been demonstrated using susceptibility weighted imaging (SWI). In the present study, a quantitative susceptibility mapping (QSM) approach is evaluated for 3-D visualization of the cartilage canals. It is hypothesized that QSM post-processing improves visualization of the cartilage canals by resolving artifacts present in the standard SWI post-processing while retaining sensitivity to the cartilage canals. Methods Ex vivo distal femoral specimens from 3- and 8-week-old piglets and a 1-month-old human cadaver were scanned at 9.4 T with a 3-D gradient recalled echo sequence suitable for SWI and QSM post-processing. The human specimen and the stifle joint of a live, 3-week-old piglet also were scanned at 7.0 T. Datasets were processed using the standard SWI method and truncated k-space division QSM approach. To compare the post-processing methods, minimum/maximum intensity projections and 3-D reconstructions of the processed datasets were generated and evaluated. Results Cartilage canals were successfully visualized using both SWI and QSM approaches. The artifactual splitting of the cartilage canals that occurs due to the dipolar phase, which was present in the SWI post-processed data, was eliminated by the QSM approach. Thus, orientation-independent visualization and better localization of the cartilage canals was achieved with the QSM approach. Combination of GRE with a mask based on QSM data further improved visualization. Conclusions Improved and artifact-free 3-D visualization of the cartilage canals was demonstrated by QSM processing of the data, especially by utilizing susceptibility data as an enhancing mask. Utilizing tissue-inherent contrast, this method allows

  13. Visualizing Coolant Flow in Sodium Reactor Subassemblies

    SciTech Connect

    2010-01-01

    Uniformity of temperature controls peak power output. Interchannel cross-flow is the principal cross-assembly energy transport mechanism. The areas of fastest flow all occur at the exterior of the assembly. Further, the fast moving region winds around the assembly in a continuous swath. This Nek5000 simulation uses an unstructured mesh with over one billion grid points, resulting in five billion degrees of freedom per time slice. High speed patches of turbulence due to vertex shedding downstream of the wires persist for about a quarter of the wire-wrap periodic length. Credits: Science: Paul Fisher and Aleks Obabko, Argonne National Laboratory
 Visualization: Hank Childs and Janet Jacobsen, Lawrence Berkeley National Laboratory

 This research used resources of the Argonne Leadership Computing Facility at Argonne National Laboratory, which is supported by the Office of Science of the U.S. Dept. of Energy under contract DE-AC02-06CH11357. This research was sponsored by the Department of Energy's Office of Nuclear Energy's NEAMS program.

  14. Flow visualizations of perpendicular blade vortex interactions

    NASA Technical Reports Server (NTRS)

    Rife, Michael C.; Davenport, William J.

    1992-01-01

    Helium bubble flow visualizations have been performed to study perpendicular interaction of a turbulent trailing vortex and a rectangular wing in the Virginia Tech Stability Tunnel. Many combinations of vortex strength, vortex-blade separation (Z(sub s)) and blade angle of attack were studied. Photographs of representative cases are presented. A range of phenomena were observed. For Z(sub s) greater than a few percent chord the vortex is deflected as it passes the blade under the influence of the local streamline curvature and its image in the blade. Initially the interaction appears to have no influence on the core. Downstream, however, the vortex core begins to diffuse and grow, presumably as a consequence of its interaction with the blade wake. The magnitude of these effects increases with reduction in Z(sub s). For Z(sub s) near zero the form of the interaction changes and becomes dependent on the vortex strength. For lower strengths the vortex appears to split into two filaments on the leading edge of the blade, one passing on the pressure and one passing on the suction side. At higher strengths the vortex bursts in the vicinity of the leading edge. In either case the core of its remnants then rapidly diffuse with distance downstream. Increase in Reynolds number did not qualitatively affect the flow apart from decreasing the amplitude of the small low-frequency wandering motions of the vortex. Changes in wing tip geometry and boundary layer trip had very little effect.

  15. Parametric Flow Visualization of Dynamic Roughness Effects

    NASA Astrophysics Data System (ADS)

    Jakkali, Vinay

    The ever growing need in the aircraft industry to enhance the performance of a flight vehicle has led to active areas of research which focus on the control of the local boundary layer by both passive and active methods. An effective flow control mechanism can improve the performance of a flight vehicle in various ways, one of which is eliminating boundary layer separation. To be effective the mechanism not only needs to control the boundary layer as desired, but also use less energy than the resulting energy savings. In this study, the effectiveness of an active flow control technique known as dynamic roughness (DR) has been explored to eliminate the laminar separation bubble near the leading edge and also to eliminate the stall on a NACA 0012 airfoil wing. As opposed to static roughness, dynamic roughness utilizes small time-dependent deforming elements or humps with displacement amplitudes that are on the order of the local boundary layer height to energize the local boundary layer. DR is primarily characterized by the maximum amplitude and operating frequency. A flow visualization study was conducted on a 2D NACA 0012 airfoil model at different angles of attack, and also varying the Reynolds number and DR actuation frequency with fixed maximum DR amplitude. The experimental results from this study suggests that DR is an effective method of reattaching a totally separated boundary layer. In addition, this study discusses some of the fundamental physics behind the working of DR and proposes some non-dimensional terms that may help to explain the driving force behind the mechanism.

  16. Flow Visualization of Forced and Natural Convection in Internal Cavities

    SciTech Connect

    John Crepeau; Hugh M. Mcllroy,Jr.; Donald M. McEligot; Keith G. Condie; Glenn McCreery; Randy Clarsean; Robert S. Brodkey; Yann G. Guezennec

    2002-01-31

    The report descries innovative flow visualization techniques, fluid mechanics measurements and computational models of flows in a spent nuclear fuel canister. The flow visualization methods used a fluid that reacted with a metal plate to show how a local reaction affects the surrounding flow. A matched index of refraction facility was used to take mean flow and turbulence measurements within a generic spent nuclear fuel canister. Computational models were also made of the flow in the canister. It was determined that the flow field in the canister was very complex, and modifications may need to be made to ensure that the spent fuel elements are completely passivated.

  17. Flow visualization. Citations from the NTIS data base

    NASA Astrophysics Data System (ADS)

    Habercom, G. E., Jr.

    1980-04-01

    Major studies concerning flow visualization for wind tunnel, water tunnel, and shock tube testing are cited. The visualization methods described include the use of smoke, water vapor, dyes, oils, bubbles, phase change paints, and particles. While many of these studies cover flow visualization techniques for specific applications, they are included because of their applicability to various research problems. This updated bibliography contains 202 abstracts, 63 of which are new entries to the previous edition.

  18. Flow visualization of turbulent boundary layer structure

    NASA Astrophysics Data System (ADS)

    Head, M. R.; Bandyopadhyay, P.

    1980-01-01

    The results from flow visualization experiments performed using an argon-ion laser to illuminate longitudinal and transverse sections of the smoke filled boundary layer in zero pressure gradient are discussed. Most of the experiments were confined to the range 600 Re sub theta 10,000. Results indicate that the boundary layer consists almost exclusively of vortex loops or hairpins, some of which may extend through the complete boundary layer thickness and all of which are inclined at a more or less constant characteristic angle of approximately 45 deg to the wall. Since the cross-stream dimensions of the hairpins appear to scale roughly with the wall variables U sub tau and nu, while their length is limited only by the boundary layer thickness, there are very large scale effects on the turbulence structure. At high Reynolds numbers (Re sub theta = 10,000) there is little evidence of large-scale coherent motions, other than a slow overturning of random agglomerations of the hairpins just mentioned.

  19. Breast tumour visualization using 3D quantitative ultrasound methods

    NASA Astrophysics Data System (ADS)

    Gangeh, Mehrdad J.; Raheem, Abdul; Tadayyon, Hadi; Liu, Simon; Hadizad, Farnoosh; Czarnota, Gregory J.

    2016-04-01

    Breast cancer is one of the most common cancer types accounting for 29% of all cancer cases. Early detection and treatment has a crucial impact on improving the survival of affected patients. Ultrasound (US) is non-ionizing, portable, inexpensive, and real-time imaging modality for screening and quantifying breast cancer. Due to these attractive attributes, the last decade has witnessed many studies on using quantitative ultrasound (QUS) methods in tissue characterization. However, these studies have mainly been limited to 2-D QUS methods using hand-held US (HHUS) scanners. With the availability of automated breast ultrasound (ABUS) technology, this study is the first to develop 3-D QUS methods for the ABUS visualization of breast tumours. Using an ABUS system, unlike the manual 2-D HHUS device, the whole patient's breast was scanned in an automated manner. The acquired frames were subsequently examined and a region of interest (ROI) was selected in each frame where tumour was identified. Standard 2-D QUS methods were used to compute spectral and backscatter coefficient (BSC) parametric maps on the selected ROIs. Next, the computed 2-D parameters were mapped to a Cartesian 3-D space, interpolated, and rendered to provide a transparent color-coded visualization of the entire breast tumour. Such 3-D visualization can potentially be used for further analysis of the breast tumours in terms of their size and extension. Moreover, the 3-D volumetric scans can be used for tissue characterization and the categorization of breast tumours as benign or malignant by quantifying the computed parametric maps over the whole tumour volume.

  20. Developments in flow visualization methods for flight research

    NASA Technical Reports Server (NTRS)

    Holmes, Bruce J.; Obara, Clifford J.; Manuel, Gregory S.; Lee, Cynthia C.

    1990-01-01

    With the introduction of modern airplanes utilizing laminar flow, flow visualization has become an important diagnostic tool in determining aerodynamic characteristics such as surface flow direction and boundary-layer state. A refinement of the sublimating chemical technique has been developed to define both the boundary-layer transition location and the transition mode. In response to the need for flow visualization at subsonic and transonic speeds and altitudes above 20,000 feet, the liquid crystal technique has been developed. A third flow visualization technique that has been used is infrared imaging, which offers non-intrusive testing over a wide range of test conditions. A review of these flow visualization methods and recent flight results is presented for a variety of modern aircraft and flight conditions.

  1. Quantitative evaluation fo cerebrospinal fluid shunt flow

    SciTech Connect

    Chervu, S.; Chervu, L.R.; Vallabhajosyula, B.; Milstein, D.M.; Shapiro, K.M.; Shulman, K.; Blaufox, M.D.

    1984-01-01

    The authors describe a rigorous method for measuring the flow of cerebrospinal fluid (CSF) in shunt circuits implanted for the relief of obstructive hydrocephalus. Clearance of radioactivity for several calibrated flow rates was determined with a Harvard infusion pump by injecting the Rickham reservoir of a Rickham-Holter valve system with 100 ..mu..Ci of Tc-99m as pertechnetate. The elliptical and the cylindrical Holter valves used as adjunct valves with the Rickham reservoir yielded two different regression lines when the clearances were plotted against flow rats. The experimental regression lines were used to determine the in vivo flow rates from clearances calculated after injecting the Rickham reservoirs of the patients. The unique clearance characteristics of the individual shunt systems available requires that calibration curves be derived for an entire system identical to one implanted in the patient being evaluated, rather than just the injected chamber. Excellent correlation between flow rates and the clinical findings supports the reliability of this method of quantification of CSF shunt flow, and the results are fully accepted by neurosurgeons.

  2. Visualization studies of turbulent transition flows in a porous medium

    NASA Technical Reports Server (NTRS)

    Bilardo, V. J.

    1983-01-01

    Results are reported for flow-visualization studies of the flow regimes of water passing through a porous medium consisting of cylindrical glass and plexiglas rods arranged in a complex and fixed three-dimensional geometry. The Reynolds number (Re) varied from 50 to 700; the flow was visualized by injecting a 5% potassium permanganate dye solution into the pores and photographing the resulting dye streaklines with both a still camera and a movie camera. The results indicate that four distinct flow regimes exist in the porous medium: (1) Darcy or creeping flow up to Re = 3; (2) steady inertia-dominated laminar flow for Re = 3-150; (3) unsteady transitional laminar flow for Re = 150-250; and (4) fully turbulent flow for Re greater than 250. It is concluded that a laminar wake instability mechanism typical of the external flow about bluff bodies may be responsible for the overall transition from laminar to turbulent flow in porous media.

  3. Holographic flow visualization. Citations from the NTIS data base

    NASA Astrophysics Data System (ADS)

    Carrigan, B.

    1980-04-01

    A bibliography containing 77 abstracts concerning the use of holographic methods in flow visualization is presented. Research covering flow in wind tunnels, gas lasers, aircraft wakes, aircraft engines, supersonic flow, and shock waves is cited. Most of the techniques involve interferometric holography.

  4. Visualizing Topic Flow in Students' Essays

    ERIC Educational Resources Information Center

    O'Rourke, Stephen T.; Calvo, Rafael A.; McNamara, Danielle S.

    2011-01-01

    Visualizing how the parts of a document relate to each other and producing automatically generated quality measures that people can understand are means that writers can use to improve the quality of their compositions. This paper presents a novel document visualization technique and a measure of quality based on the average semantic distance…

  5. Visualization of the air flow behind the automotive benchmark vent

    NASA Astrophysics Data System (ADS)

    Pech, Ondrej; Jedelsky, Jan; Caletka, Petr; Jicha, Miroslav

    2015-05-01

    Passenger comfort in cars depends on appropriate function of the cabin HVAC system. A great attention is therefore paid to the effective function of automotive vents and proper formation of the flow behind the ventilation outlet. The article deals with the visualization of air flow from the automotive benchmark vent. The visualization was made for two different shapes of the inlet channel connected to the benchmark vent. The smoke visualization with the laser knife was used. The influence of the shape of the inlet channel to the airflow direction, its enlargement and position of air flow axis were investigated.

  6. Quantitative transverse flow measurement using OCT speckle decorrelation analysis

    PubMed Central

    Liu, Xuan; Huang, Yong; Ramella-Roman, Jessica C.; Mathews, Scott A.; Kang, Jin U.

    2014-01-01

    We propose an inter-Ascan speckle decorrelation based method that can quantitatively assess blood flow normal to the direction of the OCT imaging beam. To validate this method, we performed a systematic study using both phantom and in vivo animal models. Results show that our speckle analysis method can accurately extract transverse flow speed with high spatial and temporal resolution. PMID:23455305

  7. Applications of texture mapping to volume and flow visualization

    SciTech Connect

    Max, N.; Crawfis, R.; Becker, B.

    1995-05-01

    The authors describe six visualization methods which take advantage of hardware polygon scan conversion, texture mapping, and compositing, to give interactive viewing of 3D scalar fields, and motion for 3D flows. For volume rendering, these are splatting of an optimized 3D reconstruction filter, and tetrahedral cell projection using a texture map to provide the exponential per pixel necessary for accurate opacity calculation. For flows, these are the above tetrahedral projection method for rendering the ``flow volume`` dyed after passing through a dye releasing polygon, ``splatting`` of cycled anisotropic textures to provide flow direction and motion visualization, splatting motion blurred particles to indicate flow velocity, and advecting a texture directly to show the flow motion. All these techniques are tailored to take advantage of existing graphics pipelines to produce interactive visualization tools.

  8. 3D Flow Visualization Using Texture Advection

    NASA Technical Reports Server (NTRS)

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

    2001-01-01

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

  9. FAITH Pressure-Sensitive Paint and Surface Oil Flow Visualizations

    NASA Video Gallery

    Pressure-sensitive paint and surface oil flow visualization experiments are performed on a three dimensional model of a small hill. This experiment was part of a series of measurements of the compl...

  10. Holographic flow visualization at the Langley Expansion Tube

    NASA Technical Reports Server (NTRS)

    Goad, W. K.; Burner, A. W.

    1981-01-01

    A holographic system used for flow visualization at the Langley Expansion Tube is described. A ruby laser which can be singly or doubly pulsed during the short run time of less than 300 microns is used as the light source. With holography, sensitivity adjustments can be optimized after a run instead of before a run as with conventional flow visualization techniques. This results in an increased reliability of the flow visualization available for the study of real-gas effects on flow about models. Holographic techniques such as single-plate schlieren and shadowgraph, two plate interferometry, double pulse interferometry for perfect infinite-fringe interferograms, and double-pulse interferometry used to examine changes in the flow over a short time period are described and examples presented.

  11. UFLIC: A Line Integral Convolution Algorithm for Visualizing Unsteady Flows

    NASA Technical Reports Server (NTRS)

    Shen, Han-Wei; Kao, David L.; Chancellor, Marisa K. (Technical Monitor)

    1997-01-01

    This paper presents an algorithm, UFLIC (Unsteady Flow LIC), to visualize vector data in unsteady flow fields. Using the Line Integral Convolution (LIC) as the underlying method, a new convolution algorithm is proposed that can effectively trace the flow's global features over time. The new algorithm consists of a time-accurate value depositing scheme and a successive feed-forward method. The value depositing scheme accurately models the flow advection, and the successive feed-forward method maintains the coherence between animation frames. Our new algorithm can produce time-accurate, highly coherent flow animations to highlight global features in unsteady flow fields. CFD scientists, for the first time, are able to visualize unsteady surface flows using our algorithm.

  12. A Quantitative Visual Mapping and Visualization Approach for Deep Ocean Floor Research

    NASA Astrophysics Data System (ADS)

    Hansteen, T. H.; Kwasnitschka, T.

    2013-12-01

    Geological fieldwork on the sea floor is still impaired by our inability to resolve features on a sub-meter scale resolution in a quantifiable reference frame and over an area large enough to reveal the context of local observations. In order to overcome these issues, we have developed an integrated workflow of visual mapping techniques leading to georeferenced data sets which we examine using state-of-the-art visualization technology to recreate an effective working style of field geology. We demonstrate a microbathymetrical workflow, which is based on photogrammetric reconstruction of ROV imagery referenced to the acoustic vehicle track. The advantage over established acoustical systems lies in the true three-dimensionality of the data as opposed to the perspective projection from above produced by downward looking mapping methods. A full color texture mosaic derived from the imagery allows studies at resolutions beyond the resolved geometry (usually one order of magnitude below the image resolution) while color gives additional clues, which can only be partly resolved in acoustic backscatter. The creation of a three-dimensional model changes the working style from the temporal domain of a video recording back to the spatial domain of a map. We examine these datasets using a custom developed immersive virtual visualization environment. The ARENA (Artificial Research Environment for Networked Analysis) features a (lower) hemispherical screen at a diameter of six meters, accommodating up to four scientists at once thus providing the ability to browse data interactively among a group of researchers. This environment facilitates (1) the development of spatial understanding analogue to on-land outcrop studies, (2) quantitative observations of seafloor morphology and physical parameters of its deposits, (3) more effective formulation and communication of working hypotheses.

  13. Physically-based interactive Schlieren flow visualization

    SciTech Connect

    Mccormick, Patrick S; Brownlee, Carson S; Pegoraro, Vincent; Shankar, Siddharth; Hansen, Charles D

    2009-01-01

    Understanding fluid flow is a difficult problem and of increasing importance as computational fluid dynamics produces an abundance of simulation data. Experimental flow analysis has employed techniques such as shadowgraph and schlieren imaging for centuries which allow empirical observation of inhomogeneous flows. Shadowgraphs provide an intuitive way of looking at small changes in flow dynamics through caustic effects while schlieren cutoffs introduce an intensity gradation for observing large scale directional changes in the flow. The combination of these shading effects provides an informative global analysis of overall fluid flow. Computational solutions for these methods have proven too complex until recently due to the fundamental physical interaction of light refracting through the flow field. In this paper, we introduce a novel method to simulate the refraction of light to generate synthetic shadowgraphs and schlieren images of time-varying scalar fields derived from computational fluid dynamics (CFD) data. Our method computes physically accurate schlieren and shadowgraph images at interactive rates by utilizing a combination of GPGPU programming, acceleration methods, and data-dependent probabilistic schlieren cutoffs. Results comparing this method to previous schlieren approximations are presented.

  14. Comparison of Mars Science Laboratory Reaction Control System Jet Computations With Flow Visualization and Velocimetry

    NASA Technical Reports Server (NTRS)

    Bathel, Brett F.; Danehy, Paul M.; Johansen, Craig T.; Ashcraft, Scott W.; Novak, Luke A.

    2013-01-01

    Numerical predictions of the Mars Science Laboratory reaction control system jets interacting with a Mach 10 hypersonic flow are compared to experimental nitric oxide planar laser-induced fluorescence data. The steady Reynolds Averaged Navier Stokes equations using the Baldwin-Barth one-equation turbulence model were solved using the OVERFLOW code. The experimental fluorescence data used for comparison consists of qualitative two-dimensional visualization images, qualitative reconstructed three-dimensional flow structures, and quantitative two-dimensional distributions of streamwise velocity. Through modeling of the fluorescence signal equation, computational flow images were produced and directly compared to the qualitative fluorescence data.

  15. Modeling and Visualizing Flow of Chemical Agents Across Complex Terrain

    NASA Technical Reports Server (NTRS)

    Kao, David; Kramer, Marc; Chaderjian, Neal

    2005-01-01

    Release of chemical agents across complex terrain presents a real threat to homeland security. Modeling and visualization tools are being developed that capture flow fluid terrain interaction as well as point dispersal downstream flow paths. These analytic tools when coupled with UAV atmospheric observations provide predictive capabilities to allow for rapid emergency response as well as developing a comprehensive preemptive counter-threat evacuation plan. The visualization tools involve high-end computing and massive parallel processing combined with texture mapping. We demonstrate our approach across a mountainous portion of North California under two contrasting meteorological conditions. Animations depicting flow over this geographical location provide immediate assistance in decision support and crisis management.

  16. Advanced designs for fluid flow visualization

    NASA Technical Reports Server (NTRS)

    1978-01-01

    Research was carried out on existing and new designs for minimally intrusive measurement of flow fields in the Geophysical Fluid Flow Cell and the proposed Atmospheric General Circulation Experiment. The following topics are discussed: (1) identification and removal of foreign particles, (2) search for higher dielectric photochromic solutions, (3) selection of uv light source, (4) analysis of refractive techniques and (5) examination of fresnel lens applicability.

  17. Flow visualization of lateral jet injection into swirling crossflow

    NASA Technical Reports Server (NTRS)

    Ferrell, G. B.; Aoki, K.; Lilley, D. G.

    1985-01-01

    Flow visualization experiments have been conducted to characterize the time-mean flowfield of a deflected turbulent jet in a confining cylindrical crossflow. Jet-to-crossflow velocity ratios of 2, 4, and 6 were investigated, under crossflow inlet swirler vane angles of 0 (swirler removed), 45 and 70 degrees. Smoke, neutrally-buoyant helium-filled soap bubbles, and multi-spark flow visualization were employed to highlight interesting features of the deflected jet, as well as the trajectory and spread pattern of the jet. Gross flowfield characterization was obtained for a range of lateral jet-to-crossflow velocity ratios and a range of inlet swirl strengths in the main flow. The flow visualization results agree well with the measurements obtained elsewhere with the six-orientation single hot-wire method.

  18. Smoke visualization of flow past a transversely oscillating square cylinder

    NASA Astrophysics Data System (ADS)

    Chew, Y. T.; Luo, S. C.; Ho, Q. W.

    The lock-on phenomenon of vortex shedding frequency to the oscillating frequency of a square cylinder was studied by using smoke flow visualization technique. It was found that there are five distinct regimes of flow behavior, namely lock-on type A, lock-on type B, double lock-on, triple lock-on and quasi-steady flow, depending on the reduced velocity.

  19. Structure of unsteady flows at leading- and trailing-edges: Flow visualization and its interpretation

    NASA Technical Reports Server (NTRS)

    Rockwell, D.; Atta, R.; Kramer, L.; Lawson, R.; Lusseyran, D.; Magness, C.; Sohn, D.; Staubli, T.

    1987-01-01

    Unsteady two- and three-dimensional flow structure at leading and trailing edges of bodies can be characterized effectively using recently developed techniques for acquisition and interpretation of flow visualization. The techniques addressed here include: flow image/surface pressure correlations; 3-D reconstruction of flow structure from flow images; and interactive interpretation of flow images with theoretical simulations. These techniques can be employed in conjunction with: visual correlation and ensemble-averaging, both within a given image and between images; recognition of patterns from images; and estimates of velocity eigenfunctions from images.

  20. Experimental Visualization of Flows in Packed Beds of Spheres

    NASA Technical Reports Server (NTRS)

    Hendricks, R. C.; Lattime, S.; Braun, M. J.; Athavale, M. M.

    1997-01-01

    The flow experiment consisted of an oil tunnel, 76 x 76 mm in cross-section, packed with lucite spheres. The index of refraction of the working fluid and the spheres were matched such that the physical spheres invisible to the eye and camera. By seeding the oil and illuminating the packed bed with planar laser light sheet, aligned in the direction of the bulk flow, the system fluid dynamics becomes visible and the 2-D projection was recorded at right angles to the bulk flow. The planar light sheet was traversed from one side of the tunnel to the other providing a simulated 3-D image of the entire flow field. The boundary interface between the working fluid and the sphere rendered the sphere black permitting visualization of the exact locations of the circular interfaces in both the axial and transverse directions with direct visualization of the complex interstitial spaces between the spheres within the bed. Flows were observed near the surfaces of a plane and set of spheres as well as minor circles that appear with great circles and not always uniformly ordered. In addition to visualizing a very complex flow field, it was observed that flow channeling in the direction of the bulk flow occurs between sets of adjacent spheres. Still photographs and video recordings illustrating the flow phenomena will be presented.

  1. Occlusion-free Blood Flow Animation with Wall Thickness Visualization.

    PubMed

    Lawonn, Kai; Glaßer, Sylvia; Vilanova, Anna; Preim, Bernhard; Isenberg, Tobias

    2016-01-01

    We present the first visualization tool that combines pathlines from blood flow and wall thickness information. Our method uses illustrative techniques to provide occlusion-free visualization of the flow. We thus offer medical researchers an effective visual analysis tool for aneurysm treatment risk assessment. Such aneurysms bear a high risk of rupture and significant treatment-related risks. Therefore, to get a fully informed decision it is essential to both investigate the vessel morphology and the hemodynamic data. Ongoing research emphasizes the importance of analyzing the wall thickness in risk assessment. Our combination of blood flow visualization and wall thickness representation is a significant improvement for the exploration and analysis of aneurysms. As all presented information is spatially intertwined, occlusion problems occur. We solve these occlusion problems by dynamic cutaway surfaces. We combine this approach with a glyph-based blood flow representation and a visual mapping of wall thickness onto the vessel surface. We developed a GPU-based implementation of our visualizations which facilitates wall thickness analysis through real-time rendering and flexible interactive data exploration mechanisms. We designed our techniques in collaboration with domain experts, and we provide details about the evaluation of the technique and tool.

  2. A synchronous strobed laser light sheet for rotor flow visualization

    NASA Astrophysics Data System (ADS)

    Leighty, Bradley D.; Rhodes, David B.; Franke, John M.; Jones, Stephen B.

    1991-05-01

    A synchronous strobed laser light sheet generator was designed and used for flow visualization of a helicopter rotor model. The laser light sheet strobe circuit was designed to allow selectable blade position viewing, strobe duration, and multiple pulses per revolution for rotors having 2 to 9 blades. A slip-sync mode permits slow motion visualization of the flow field over complete rotations of the rotor. The design was tested at NASA Langley Research Center's 14 by 22 foot subsonic tunnel where the flow was seeded with propylene glycol smoke. Between runs, a calibration grid board was placed in the plane of the laser sheet and recorded with the video camera at the position used to record the flow field. The system was used to make 2-dimensional flow field cuts of a four-bladed rotor operating at wind tunnel speeds up to 79.25 meters per second (260 feet per second).

  3. Reversal of cortical information flow during visual imagery as compared to visual perception.

    PubMed

    Dentico, Daniela; Cheung, Bing Leung; Chang, Jui-Yang; Guokas, Jeffrey; Boly, Melanie; Tononi, Giulio; Van Veen, Barry

    2014-10-15

    The role of bottom-up and top-down connections during visual perception and the formation of mental images was examined by analyzing high-density EEG recordings of brain activity using two state-of-the-art methods for assessing the directionality of cortical signal flow: state-space Granger causality and dynamic causal modeling. We quantified the directionality of signal flow in an occipito-parieto-frontal cortical network during perception of movie clips versus mental replay of the movies and free visual imagery. Both Granger causality and dynamic causal modeling analyses revealed an increased top-down signal flow in parieto-occipital cortices during mental imagery as compared to visual perception. These results are the first direct demonstration of a reversal of the predominant direction of cortical signal flow during mental imagery as compared to perception. PMID:24910071

  4. Reversal of cortical information flow during visual imagery as compared to visual perception

    PubMed Central

    Dentico, Daniela; Cheung, Bing Leung; Chang, Jui-Yang; Guokas, Jeffrey; Boly, Melanie; Tononi, Giulio; Van Veen, Barry

    2014-01-01

    The role of bottom-up and top-down connections during visual perception and the forming of mental images was examined by analyzing high-density EEG recordings of brain activity using two state-of-the-art methods for assessing the directionality of cortical signal flow: state-space Granger causality and dynamic causal modeling. We quantified the directionality of signal flow in an occipito-parieto-frontal cortical network during perception of movie clips versus mental replay of the movies and free visual imagery. Both Granger causality and dynamic causal modeling analyses revealed increased top-down signal flow in parieto-occipital cortices during mental imagery as compared to visual perception. These results are the first direct demonstration of a reversal of the predominant direction of cortical signal flow during mental imagery as compared to perception. PMID:24910071

  5. Optical coherence Doppler tomography for quantitative cerebral blood flow imaging

    PubMed Central

    You, Jiang; Du, Congwu; Volkow, Nora D.; Pan, Yingtian

    2014-01-01

    Optical coherence Doppler tomography (ODT) is a promising neurotechnique that permits 3D imaging of the cerebral blood flow (CBF) network; however, quantitative CBF velocity (CBFv) imaging remains challenging. Here we present a simple phase summation method to enhance slow capillary flow detection sensitivity without sacrificing dynamic range for fast flow and vessel tracking to improve angle correction for absolute CBFv quantification. Flow phantom validation indicated that the CBFv quantification accuracy increased from 15% to 91% and the coefficient of variation (CV) decreased 9.3-fold; in vivo mouse brain validation showed that CV decreased 4.4-/10.8- fold for venular/arteriolar flows. ODT was able to identify cocaine-elicited microischemia and quantify CBFv disruption in branch vessels and capillaries that otherwise would have not been possible. PMID:25401033

  6. Towards the quantitative evaluation of visual attention models.

    PubMed

    Bylinskii, Z; DeGennaro, E M; Rajalingham, R; Ruda, H; Zhang, J; Tsotsos, J K

    2015-11-01

    Scores of visual attention models have been developed over the past several decades of research. Differences in implementation, assumptions, and evaluations have made comparison of these models very difficult. Taxonomies have been constructed in an attempt at the organization and classification of models, but are not sufficient at quantifying which classes of models are most capable of explaining available data. At the same time, a multitude of physiological and behavioral findings have been published, measuring various aspects of human and non-human primate visual attention. All of these elements highlight the need to integrate the computational models with the data by (1) operationalizing the definitions of visual attention tasks and (2) designing benchmark datasets to measure success on specific tasks, under these definitions. In this paper, we provide some examples of operationalizing and benchmarking different visual attention tasks, along with the relevant design considerations.

  7. Towards the quantitative evaluation of visual attention models.

    PubMed

    Bylinskii, Z; DeGennaro, E M; Rajalingham, R; Ruda, H; Zhang, J; Tsotsos, J K

    2015-11-01

    Scores of visual attention models have been developed over the past several decades of research. Differences in implementation, assumptions, and evaluations have made comparison of these models very difficult. Taxonomies have been constructed in an attempt at the organization and classification of models, but are not sufficient at quantifying which classes of models are most capable of explaining available data. At the same time, a multitude of physiological and behavioral findings have been published, measuring various aspects of human and non-human primate visual attention. All of these elements highlight the need to integrate the computational models with the data by (1) operationalizing the definitions of visual attention tasks and (2) designing benchmark datasets to measure success on specific tasks, under these definitions. In this paper, we provide some examples of operationalizing and benchmarking different visual attention tasks, along with the relevant design considerations. PMID:25951756

  8. MEANS FOR VISUALIZING FLUID FLOW PATTERNS

    DOEpatents

    Lynch, F.E.; Palmer, L.D.; Poppendick, H.F.; Winn, G.M.

    1961-05-16

    An apparatus is given for determining both the absolute and relative velocities of a phosphorescent fluid flowing through a transparent conduit. The apparatus includes a source for exciting a narrow trsnsverse band of the fluid to phosphorescence, detecting means such as a camera located downstream from the exciting source to record the shape of the phosphorescent band as it passes, and a timer to measure the time elapsed between operation of the exciting source and operation of the camera.

  9. A Volume Rendering Framework for Visualizing 3D Flow Fields

    NASA Astrophysics Data System (ADS)

    Hsieh, Hsien-Hsi; Li, Liya; Shen, Han-Wei; Tai, Wen-Kai

    In this paper, we present a volume rendering framework for visualizing 3D flow fields. We introduce the concept of coherence field which evaluates the representativeness of a given streamline set for the underlying 3D vector field. Visualization of the coherence field can provide effective visual feedback to the user for incremental insertion of more streamline seeds. Given an initial set of streamlines, a coherence volume is constructed from a distance field to measure the similarity between the existing streamlines and those in their nearby regions based on the difference between the approximate and the actual vector directions. With the visual feedback obtained from rendering the coherence volume, new streamline seeds can be selected by the user or by a heuristic seed selection algorithm to adaptively improve the coherence volume. An improved volume rendering technique that can render user-defined appearance textures is proposed to facilitate macro-visualization of 3D vector fields.

  10. Visualization of entry flow separation for oscillating flow in tubes

    NASA Technical Reports Server (NTRS)

    Qiu, Songgang; Simon, Terence W.

    1992-01-01

    Neutrally buoyant helium-filled soap bubbles with laser illumination are used to document entry flow separation for oscillating flow in tubes. For a symmetric entry case, the size of the separation zone appears to mildly depend on Reynolds number in the acceleration phase, but is roughly Reynolds number independent in the deceleration phase. For the asymmetric entry case, the separation zone was larger and appeared to grow somewhat during the deceleration phase. The separation zones for both entry geometry cases remain relatively small throughout the cycle. This is different from what would be observed in all-laminar, oscillator flows and is probably due to the high turbulence of the flow, particularly during the deceleration phase of the cycle.

  11. Flow visualization and flow field measurements of a 1/12 scale tilt rotor aircraft in hover

    NASA Technical Reports Server (NTRS)

    Coffen, Charles D.; George, Albert R.; Hardinge, Hal; Stevenson, Ryan

    1991-01-01

    The results are given of flow visualization studies and inflow velocity field measurements performed on a 1/12 scale model of the XV-15 tilt rotor aircraft in the hover mode. The complex recirculating flow due to the rotor-wake-body interactions characteristic of tilt rotors was studied visually using neutrally buoyant soap bubbles and quantitatively using hot wire anemometry. Still and video photography were used to record the flow patterns. Analysis of the photos and video provided information on the physical dimensions of the recirculating fountain flow and on details of the flow including the relative unsteadiness and turbulence characteristics of the flow. Recirculating flows were also observed along the length of the fuselage. Hot wire anemometry results indicate that the wing under the rotor acts to obstruct the inflow causing a deficit in the inflow velocities over the inboard region of the model. Hot wire anemometry also shows that the turbulence intensities in the inflow are much higher in the recirculating fountain reingestion zone.

  12. An annotation system for 3D fluid flow visualization

    NASA Technical Reports Server (NTRS)

    Loughlin, Maria M.; Hughes, John F.

    1995-01-01

    Annotation is a key activity of data analysis. However, current systems for data analysis focus almost exclusively on visualization. We propose a system which integrates annotations into a visualization system. Annotations are embedded in 3D data space, using the Post-it metaphor. This embedding allows contextual-based information storage and retrieval, and facilitates information sharing in collaborative environments. We provide a traditional database filter and a Magic Lens filter to create specialized views of the data. The system has been customized for fluid flow applications, with features which allow users to store parameters of visualization tools and sketch 3D volumes.

  13. Flow visualization techniques in the Airborne Laser Laboratory program

    NASA Technical Reports Server (NTRS)

    Walterick, R. E.; Vankuren, J. T.

    1980-01-01

    A turret/fairing assembly for laser applications was designed and tested. Wind tunnel testing was conducted using flow visualization techniques. The techniques used have included the methods of tufting, encapsulated liquid crystals, oil flow, sublimation and schlieren and shadowgraph photography. The results were directly applied to the design of fairing shapes for minimum drag and reduced turret buffet. In addition, the results are of primary importance to the study of light propagation paths in the near flow field of the turret cavity. Results indicate that the flow in the vicinity of the turret is an important factor for consideration in the design of suitable turret/fairing or aero-optic assemblies.

  14. The use of oil for in-flight flow visualization

    NASA Technical Reports Server (NTRS)

    Curry, R. E.; Meyer, R. R., Jr.; Oconnor, M.

    1984-01-01

    Oil was used to visualize inflight aerodynamic characteristics such as boundary layer transition, shock wave location, regions of separated flow, and surface flow direction. The technique, which is similar to wind tunnel oil-flow testing, involves an oil mixture to test aircraft before takeoff. After takeoff, the airplane climbs immediately to the test altitude and photographs are taken. The developmental experience is summarized, several examples of inflight oil-flow photographs are presented and discussed, and an approach for potential users of the technique is presented.

  15. Quantitative description of fluid flows produced by left-right cilia in zebrafish.

    PubMed

    Fox, Craig; Manning, M Lisa; Amack, Jeffrey D

    2015-01-01

    Motile cilia generate directional flows that move mucus through airways, cerebrospinal fluid through brain ventricles, and oocytes through fallopian tubes. In addition, specialized monocilia beat in a rotational pattern to create asymmetric flows that are involved in establishing the left-right (LR) body axis during embryogenesis. These monocilia, which we refer to as "left-right cilia," produce a leftward flow of extraembryonic fluid in a transient "organ of asymmetry" that directs asymmetric signaling and development of LR asymmetries in the cardiovascular system and gastrointestinal tract. The asymmetric flows are thought to establish a chemical gradient and/or activate mechanosensitive cilia to initiate calcium ion signals and a conserved Nodal (TGFβ) pathway on the left side of the embryo, but the mechanisms underlying this process remain unclear. The zebrafish organ of asymmetry, called Kupffer's vesicle, provides a useful model system for investigating LR cilia and cilia-powered fluid flows. Here, we describe methods to visualize flows in Kupffer's vesicle using fluorescent microspheres and introduce a new and freely available MATLAB particle tracking code to quantitatively describe these flows. Analysis of normal and aberrant flows indicates this approach is useful for characterizing flow properties that impact LR asymmetry and may be more broadly applicable for quantifying other cilia flows. PMID:25837391

  16. In-flight propeller flow visualization using fluorescent minitufts

    NASA Technical Reports Server (NTRS)

    Crowder, J. P.

    1982-01-01

    Extension of fluorescent minutuft method to in-flight flow visualization on propellers is described. Extremely thin nylon monofilament for the minitufts, is used in a process of attaching them to the test surface with small drops of lacquer-like adhesive, and the use of fluorescence photography for recording the minituft patterns. Using this method, thousands of minitufts can be applied to small, high speed wind tunnel models without affecting the airflow. The minitufts can remain in place throughout a wind tunnel test, permitting nonintrusive flow visualization data to be acquired at any time.

  17. Advances in flow visualization using liquid-crystal coatings

    NASA Technical Reports Server (NTRS)

    Holmes, Bruce J.; Obara, Clifford J.

    1987-01-01

    This paper discusses a new four-part mixing method for visualizing boundary layer flows, including transitions, separation, and shock locations, by the use of liquid-crystal coatings. The method controls the event temperature and color-play bandwidth best suited to specific experimental conditions, and is easily learned. The method is applicable almost throughout the altitude and speed ranges for subsonic aircraft flight envelopes, and is also applicable to supersonic flow visualization and for general use in high- and low-speed wind tunnel and water tunnel testing.

  18. Single Molecule Visualization of DNA in Pure Shear Flow

    NASA Astrophysics Data System (ADS)

    Smith, Connie; Duggal, Rajat; Pasquali, Matteo

    2003-03-01

    Polymers are ever-present in society from plastic bottles to DNA. The study of single molecule dynamics will provide the opportunity for advances in fields from synthetic polymer coatings to gene therapy. Many applications involve flow of dilute polymer solutions in viscous solvents. These long, flexible polymer chains (DNA) are coiled at rest in solution. The configuration of the molecules is altered by the applied flow which, in turn, affects the dynamics of the flow. Control of flow allows for manipulation of the DNA molecules. Our apparatus consists of a rectangular channel that has been plasma etched into a silicon wafer with pressure driven flow (pulse-free syringe pump). The dynamics of the DNA molecules in flow are monitored using fluorescence microscopy and digital imaging. The flow channel was designed to allow for visualization of the molecules in the plane defined by velocity and velocity gradient instead of the plane identified by the velocity and the vorticity (previously studied by Smith et al (1999) and LeDuc et al (1999)). Moreover, we can visualize the DNA in a flow where the velocity gradient is not uniform. The individual and average conformations (size and orientation) of the flowing DNA molecules are being studied as a function of the Weissenberg number (product of strain rate and DNA relaxation time) and distance from the channel walls.

  19. Patterns in the sky: Natural visualization of aircraft flow fields

    NASA Technical Reports Server (NTRS)

    Campbell, James F.; Chambers, Joseph R.

    1994-01-01

    The objective of the current publication is to present the collection of flight photographs to illustrate the types of flow patterns that were visualized and to present qualitative correlations with computational and wind tunnel results. Initially in section 2, the condensation process is discussed, including a review of relative humidity, vapor pressure, and factors which determine the presence of visible condensate. Next, outputs from computer code calculations are postprocessed by using water-vapor relationships to determine if computed values of relative humidity in the local flow field correlate with the qualitative features of the in-flight condensation patterns. The photographs are then presented in section 3 by flow type and subsequently in section 4 by aircraft type to demonstrate the variety of condensed flow fields that was visualized for a wide range of aircraft and flight maneuvers.

  20. Numerical Flow Visualization in Basic- and Hyper-Cluster Spheres

    NASA Technical Reports Server (NTRS)

    Hendricks, R. C.; Athavale, M. M.; Braun, M. J.; Lattime, S.

    1997-01-01

    Packed spherical particle beds have wide applications throughout the process industry and are usually analyzed using an appropriate combination of laminar and turbulent flows with empirically derived coefficients of which the Ergun (1952) relation is probably the best known. The 3-D complexity of the void distribution within the beds has precluded detailed studies of sphere clusters. Numerical modeling and flow vector visualization for the basic tetra- and hexa-sphere clusters and two hyper-sphere clusters are presented at two Reynolds numbers, 400 and 1200. Cutting planes are used to enable visualization of the complex flows generated within the sphere clusters and are discussed herein. The boundary conditions and flow fields for the simple clusters are also compared to the hyper-clusters with larger variations found for hexa-clusters.

  1. Ultrafast quantitative time-stretch imaging flow cytometry of phytoplankton

    NASA Astrophysics Data System (ADS)

    Lai, Queenie T. K.; Lau, Andy K. S.; Tang, Anson H. L.; Wong, Kenneth K. Y.; Tsia, Kevin K.

    2016-03-01

    Comprehensive quantification of phytoplankton abundance, sizes and other parameters, e.g. biomasses, has been an important, yet daunting task in aquatic sciences and biofuel research. It is primarily because of the lack of effective tool to image and thus accurately profile individual microalgae in a large population. The phytoplankton species are highly diversified and heterogeneous in terms of their sizes and the richness in morphological complexity. This fact makes time-stretch imaging, a new ultrafast real-time optical imaging technology, particularly suitable for ultralarge-scale taxonomic classification of phytoplankton together with quantitative image recognition and analysis. We here demonstrate quantitative imaging flow cytometry of single phytoplankton based on quantitative asymmetric-detection time-stretch optical microscopy (Q-ATOM) - a new time-stretch imaging modality for label-free quantitative phase imaging without interferometric implementations. Sharing the similar concept of Schlieren imaging, Q-ATOM accesses multiple phase-gradient contrasts of each single phytoplankton, from which the quantitative phase profile is computed. We employ such system to capture, at an imaging line-scan rate of 11.6 MHz, high-resolution images of two phytoplankton populations (scenedesmus and chlamydomonas) in ultrafast microfluidic flow (3 m/s). We further perform quantitative taxonomic screening analysis enabled by this technique. More importantly, the system can also generate quantitative phase images of single phytoplankton. This is especially useful for label-free quantification of biomasses (e.g. lipid droplets) of the particular species of interest - an important task adopted in biofuel applications. Combining machine learning for automated classification, Q-ATOM could be an attractive platform for continuous and real-time ultralarge-scale single-phytoplankton analysis.

  2. Flow quantitation by radio frequency analysis of contrast echocardiography.

    PubMed

    Rovai, D; Lombardi, M; Mazzarisi, A; Landini, L; Taddei, L; Distante, A; Benassi, A; L'Abbate, A

    1993-03-01

    Contrast echocardiography has the potential for measuring cardiac output and regional blood flow. However, accurate quantitation is limited both by the use of non-standard contrast agents and by the electronic signal distortion inherent to the echocardiographic instruments. Thus, the aim of this study is to quantify flow by combining a stable contrast agent and a modified echo equipment, able to sample the radio frequency (RF) signal from a region of interest (ROI) in the echo image. The contrast agent SHU-454 (0.8 ml) was bolus injected into an in vitro calf vein, at 23 flow rates (ranging from 376 to 3620 ml/min) but constant volume and pressure. The ROI was placed in the centre of the vein, the RF signal was processed in real time and transferred to a personal computer to generate time-intensity curves. In the absence of recirculation, contrast washout slope and mean transit time (MTT) of curves (1.11-8.52 seconds) yielded excellent correlations with flow: r = 0.93 and 0.95, respectively. To compare the accuracy of RF analysis with that of conventional image processing as to flow quantitation, conventional images were collected in the same flow model by two different scanners: a) the mechanical sector scanner used for RF analysis, and b) a conventional electronic sector scanner. These images were digitized off-line, mean videodensity inside an identical ROI was measured and time-intensity curves were built. MTT by RF was shorter than by videodensitometric analysis of the images generated by the same scanner (p < 0.001). In contrast, MTT by RF was longer than by the conventional scanner (p < 0.001). Significant differences in MTT were also found with changes in the gain setting controls of the conventional scanner. To study the stability of the contrast effect, 6 contrast injections (20 ml) were performed at a constant flow rate during recirculation: the spontaneous decay in RF signal intensity (t1/2 = 64 +/- 8 seconds) was too long to affect MTT significantly

  3. Special purpose computer system for flow visualization using holography technology.

    PubMed

    Abe, Yukio; Masuda, Nobuyuki; Wakabayashi, Hideaki; Kazo, Yuta; Ito, Tomoyoshi; Satake, Shin-ichi; Kunugi, Tomoaki; Sato, Kazuho

    2008-05-26

    We have designed a special purpose computer system for visualizing fluid flow using digital holographic particle tracking velocimetry (DHPTV). This computer contains an Field Programmble Gate Array (FPGA) chip in which a pipeline for calculating the intensity of an object from a hologram by fast Fourier transform is installed. This system can produce 100 reconstructed images from a 1024 x 1024-grid hologram in 3.3 sec. It is expected that this system will contribute to fluid flow analysis.

  4. The use of liquid crystals for surface flow visualization

    NASA Technical Reports Server (NTRS)

    Smith, Stephen C.

    1990-01-01

    The use of shear-sensitive liquid crystals has become an established technique for diagnostic flow visualization. This technique has been demonstrated to illustrate laminar boundary-layer transition, laminar bubbles, shocks, and separation in flight and wind-tunnel environments. Typical results demonstrate the range of flow features which can be illustrated and some of the challenges and pitfalls which must be addressed. A few remaining issues are discussed which should be resolved to develop this technique to full maturity.

  5. Task centered visualization of Electronic Medical Record flow sheet.

    PubMed

    Xie, Zhong; Gregg, Peggy; Zhang, Jiajie

    2003-01-01

    Usability problem of Electronic Medical Record (EMR) systems is a major hurdle for their acceptance. In this study we used the methodology of Human-Centered Distributed Information Design (HCDID) to compare and evaluate Flow Sheet module of two commercial EMR systems. After which we tried to develop usable interface of a flow sheet using visualization, focusing on task-representation mapping during design and development.

  6. Visualization of tumor vascularity in a rabbit VX2 carcinoma by Doppler flow mapping.

    PubMed

    Rubin, J M; Carson, P L; Zlotecki, R A; Ensminger, W D

    1987-03-01

    Using an ultrasonic dynamic flow imager that displays both soft tissues and color-coded flow in the same two-dimensional slice, we were able to display neovascularity in a rabbit VX2 carcinoma. Intravenous infusion of epinephrine altered the flow dynamics in two arteries, one within the tumor and one at the periphery. Further, we were also able to visualize areas of multidirectional flow presumably due to complex arterial patterns and arteriovenous shunts. It is concluded that the color-coded Doppler instrument may overcome some of the methodological problems associated with tumor diagnosis via flow characteristics in the human breast. The literature indicates that the vascular response to the vasoactive drugs or thermal stress may increase differentiation of malignant breast lesions. This experiment suggests that Doppler images and measurements may be made efficiently with color-coded Doppler images, particularly with the addition of more quantitative features to the imager. PMID:3550135

  7. Visualization periodic flows in a continuously stratified fluid.

    NASA Astrophysics Data System (ADS)

    Bardakov, R.; Vasiliev, A.

    2012-04-01

    To visualize the flow pattern of viscous continuously stratified fluid both experimental and computational methods were developed. Computational procedures were based on exact solutions of set of the fundamental equations. Solutions of the problems of flows producing by periodically oscillating disk (linear and torsion oscillations) were visualized with a high resolutions to distinguish small-scale the singular components on the background of strong internal waves. Numerical algorithm of visualization allows to represent both the scalar and vector fields, such as velocity, density, pressure, vorticity, stream function. The size of the source, buoyancy and oscillation frequency, kinematic viscosity of the medium effects were traced in 2D an 3D posing problems. Precision schlieren instrument was used to visualize the flow pattern produced by linear and torsion oscillations of strip and disk in a continuously stratified fluid. Uniform stratification was created by the continuous displacement method. The buoyancy period ranged from 7.5 to 14 s. In the experiments disks with diameters from 9 to 30 cm and a thickness of 1 mm to 10 mm were used. Different schlieren methods that are conventional vertical slit - Foucault knife, vertical slit - filament (Maksoutov's method) and horizontal slit - horizontal grating (natural "rainbow" schlieren method) help to produce supplementing flow patterns. Both internal wave beams and fine flow components were visualized in vicinity and far from the source. Intensity of high gradient envelopes increased proportionally the amplitude of the source. In domains of envelopes convergence isolated small scale vortices and extended mushroom like jets were formed. Experiments have shown that in the case of torsion oscillations pattern of currents is more complicated than in case of forced linear oscillations. Comparison with known theoretical model shows that nonlinear interactions between the regular and singular flow components must be taken

  8. Flow visualization in a low-density plasma channel

    NASA Astrophysics Data System (ADS)

    Kimmel, R. L.; Hayes, J. R.; Estevadeordal, J.; Crafton, J. W.; Fonov, S. D.; Gogineni, S.

    2010-04-01

    A schlieren system and surface-stress-sensitive film system were developed for a plasma channel which posed unique challenges for flow visualization because of the combination of low air density and the presence of plasma discharges. Temperature-sensitive paint and direct-current discharge were also applied to flow visualization. Three pulsed schlieren light sources were evaluated. A light-emitting diode (LED), a xenon NanopulserTM and laser breakdown, were tested on identical flowfields. The LED provided excellent illumination, with pulses ranging from μs to continuous. The NanopulserTM provided excellent, short-duration images, although illumination varied from shot-to-shot. Laser-breakdown provided short-duration, incoherent illumination that was constant from pulse-to-pulse. The surface-stress-sensitive film was applied to surface flow visualization. A low-modulus elastomer doped with a luminescent dye was used to visualize the surface shear stress and pressure field in laminar shock boundary layer interactions. Intensity distributions from the dye were imaged to interrogate the surface pressure gradients. Displacement of surface markers provided shear information. Results showed the presence of Görtler vortices in the reattaching shear flow. Görtler vortices were also evident in temperature-sensitive paint images and in the plasma discharge glow. These vortices were evident in the intensity images from the elastomer, which could be related to the surface pressure gradient, but were not readily evident in surface shear measurements.

  9. Simple method of supersonic flow visualization using smoke

    NASA Astrophysics Data System (ADS)

    Miller, L. S.; Irani, E.

    1992-01-01

    A modified smoke wire visualization method for application in high-speed and supersonic flows has been developed which produces a large number of fine smoke filaments that do not dissipate. This new technique is easily implemented in an open-inlet induction-type supersonic wind tunnel. Shock waves and expansion regions are clearly identified by the smoke filament behavior.

  10. STRING 3: An Advanced Groundwater Flow Visualization Tool

    NASA Astrophysics Data System (ADS)

    Schröder, Simon; Michel, Isabel; Biedert, Tim; Gräfe, Marius; Seidel, Torsten; König, Christoph

    2016-04-01

    The visualization of 3D groundwater flow is a challenging task. Previous versions of our software STRING [1] solely focused on intuitive visualization of complex flow scenarios for non-professional audiences. STRING, developed by Fraunhofer ITWM (Kaiserslautern, Germany) and delta h Ingenieurgesellschaft mbH (Witten, Germany), provides the necessary means for visualization of both 2D and 3D data on planar and curved surfaces. In this contribution we discuss how to extend this approach to a full 3D tool and its challenges in continuation of Michel et al. [2]. This elevates STRING from a post-production to an exploration tool for experts. In STRING moving pathlets provide an intuition of velocity and direction of both steady-state and transient flows. The visualization concept is based on the Lagrangian view of the flow. To capture every detail of the flow an advanced method for intelligent, time-dependent seeding is used building on the Finite Pointset Method (FPM) developed by Fraunhofer ITWM. Lifting our visualization approach from 2D into 3D provides many new challenges. With the implementation of a seeding strategy for 3D one of the major problems has already been solved (see Schröder et al. [3]). As pathlets only provide an overview of the velocity field other means are required for the visualization of additional flow properties. We suggest the use of Direct Volume Rendering and isosurfaces for scalar features. In this regard we were able to develop an efficient approach for combining the rendering through raytracing of the volume and regular OpenGL geometries. This is achieved through the use of Depth Peeling or A-Buffers for the rendering of transparent geometries. Animation of pathlets requires a strict boundary of the simulation domain. Hence, STRING needs to extract the boundary, even from unstructured data, if it is not provided. In 3D we additionally need a good visualization of the boundary itself. For this the silhouette based on the angle of

  11. Quantitation of glycerophosphorylcholine by flow injection analysis using immobilized enzymes.

    PubMed

    Mancini, A; Del Rosso, F; Roberti, R; Caligiana, P; Vecchini, A; Binaglia, L

    1996-09-20

    A method for quantitating glycerophosphorylcholine by flow injection analysis is reported in the present paper. Glycerophosphorylcholine phosphodiesterase and choline oxidase, immobilized on controlled porosity glass beads, are packed in a small reactor inserted in a flow injection manifold. When samples containing glycerophosphorylcholine are injected, glycerophosphorylcholine is hydrolyzed into choline and sn-glycerol-3-phosphate. The free choline produced in this reaction is oxidized to betain and hydrogen peroxide. Hydrogen peroxide is detected amperometrically. Quantitation of glycerophosphorylcholine in samples containing choline and phosphorylcholine is obtained inserting ahead of the reactor a small column packed with a mixed bed ion exchange resin. The time needed for each determination does not exceed one minute. The present method, applied to quantitate glycerophosphorylcholine in samples of seminal plasma, gave results comparable with those obtained using the standard enzymatic-spectrophotometric procedure. An alternative procedure, making use of co-immobilized glycerophosphorylcholine phosphodiesterase and glycerol-3-phosphate oxidase for quantitating glycerophosphorylcholine, glycerophosphorylethanolamine and glycerophosphorylserine is also described. PMID:8905629

  12. Visualization of In-Flight Flow Phenomena Using Infrared Thermography

    NASA Technical Reports Server (NTRS)

    Banks, D. W.; vanDam, C. P.; Shiu, H. J.; Miller, G. M.

    2000-01-01

    Infrared thermography was used to obtain data on the state of the boundary layer of a natural laminar flow airfoil in supersonic flight. In addition to the laminar-to-turbulent transition boundary, the infrared camera was able to detect shock waves and present a time dependent view of the flow field. A time dependent heat transfer code was developed to predict temperature distributions on the test subject and any necessary surface treatment. A commercially available infrared camera was adapted for airborne use in this application. Readily available infrared technology has the capability to provide detailed visualization of various flow phenomena in subsonic to hypersonic flight regimes.

  13. Quantitative blood flow measurements in the small animal cardiopulmonary system using digital subtraction angiography

    SciTech Connect

    Lin Mingde; Marshall, Craig T.; Qi, Yi; Johnston, Samuel M.; Badea, Cristian T.; Piantadosi, Claude A.; Johnson, G. Allan

    2009-11-15

    Purpose: The use of preclinical rodent models of disease continues to grow because these models help elucidate pathogenic mechanisms and provide robust test beds for drug development. Among the major anatomic and physiologic indicators of disease progression and genetic or drug modification of responses are measurements of blood vessel caliber and flow. Moreover, cardiopulmonary blood flow is a critical indicator of gas exchange. Current methods of measuring cardiopulmonary blood flow suffer from some or all of the following limitations--they produce relative values, are limited to global measurements, do not provide vasculature visualization, are not able to measure acute changes, are invasive, or require euthanasia. Methods: In this study, high-spatial and high-temporal resolution x-ray digital subtraction angiography (DSA) was used to obtain vasculature visualization, quantitative blood flow in absolute metrics (ml/min instead of arbitrary units or velocity), and relative blood volume dynamics from discrete regions of interest on a pixel-by-pixel basis (100x100 {mu}m{sup 2}). Results: A series of calibrations linked the DSA flow measurements to standard physiological measurement using thermodilution and Fick's method for cardiac output (CO), which in eight anesthetized Fischer-344 rats was found to be 37.0{+-}5.1 ml/min. Phantom experiments were conducted to calibrate the radiographic density to vessel thickness, allowing a link of DSA cardiac output measurements to cardiopulmonary blood flow measurements in discrete regions of interest. The scaling factor linking relative DSA cardiac output measurements to the Fick's absolute measurements was found to be 18.90xCO{sub DSA}=CO{sub Fick}. Conclusions: This calibrated DSA approach allows repeated simultaneous visualization of vasculature and measurement of blood flow dynamics on a regional level in the living rat.

  14. A water tunnel flow visualization study of the F-15

    NASA Technical Reports Server (NTRS)

    Lorincz, D. J.

    1978-01-01

    Water tunnel studies were performed to qualitatively define the flow field of the F-15 aircraft. Two lengthened forebodies, one with a modified cross-sectional shape, were tested in addition to the basic forebody. Particular emphasis was placed on defining vortex flows generated at high angles of attack. The flow visualization tests were conducted in the Northrop diagnostic water tunnel using a 1/48-scale model of the F-15. Flow visualization pictures were obtained over an angle-of-attack range to 55 deg and sideslip angles up to 10 deg. The basic aircraft configuration was investigated in detail to determine the vortex flow field development, vortex path, and vortex breakdown characteristics as a function of angle of attack and sideslip. Additional tests showed that the wing upper surface vortex flow fields were sensitive to variations in inlet mass flow ratio and inlet cowl deflection angle. Asymmetries in the vortex systems generated by each of the three forebodies were observed in the water tunnel at zero sideslip and high angles of attack.

  15. Multiple visual quantitative cues enhance discrimination of dynamic stimuli during infancy.

    PubMed

    Baker, Joseph M; Mahamane, Salif P; Jordan, Kerry E

    2014-06-01

    Infants possess basic capabilities to assess various quantitative properties such as number, size, and time. Preverbal discriminations are approximate, however, and are similarly limited across these dimensions. Here, we present the first evidence that multiple sources of quantitative unisensory information about dynamic stimuli-namely, simultaneous visual cues to changes in both number and surface area-may accelerate 6-month-olds' quantitative competence. Using a habituation-dishabituation paradigm, results from Experiment 1 demonstrate that, when provided with such visual cues to multiple quantitative properties that occur in the same direction, infants make more precise discriminations than has been shown when they receive information about either cue alone. Moreover, Experiment 2 demonstrates that infants' discrimination also benefits from simultaneous visual cues to quantitative changes that occur in opposite directions. Finally, Experiment 3 demonstrates that these findings are not driven by infants' ability to discriminate a 2:3 ratio change in surface area of a dynamic stimulus alone. Thus, we hypothesize that enhanced quantitative discrimination occurs because simultaneous visual quantitative changes may be more salient than single-source information, which could better recruit attention and result in more precise learning and remembering.

  16. Quantitative Simulations of MST Visual Receptive Field Properties Using a Template Model of Heading Estimation

    NASA Technical Reports Server (NTRS)

    Stone, Leland S.; Perrone, J. A.

    1997-01-01

    We previously developed a template model of primate visual self-motion processing that proposes a specific set of projections from MT-like local motion sensors onto output units to estimate heading and relative depth from optic flow. At the time, we showed that that the model output units have emergent properties similar to those of MSTd neurons, although there was little physiological evidence to test the model more directly. We have now systematically examined the properties of the model using stimulus paradigms used by others in recent single-unit studies of MST: 1) 2-D bell-shaped heading tuning. Most MSTd neurons and model output units show bell-shaped heading tuning. Furthermore, we found that most model output units and the finely-sampled example neuron in the Duffy-Wurtz study are well fit by a 2D gaussian (sigma approx. 35deg, r approx. 0.9). The bandwidth of model and real units can explain why Lappe et al. found apparent sigmoidal tuning using a restricted range of stimuli (+/-40deg). 2) Spiral Tuning and Invariance. Graziano et al. found that many MST neurons appear tuned to a specific combination of rotation and expansion (spiral flow) and that this tuning changes little for approx. 10deg shifts in stimulus placement. Simulations of model output units under the same conditions quantitatively replicate this result. We conclude that a template architecture may underlie MT inputs to MST.

  17. Near-Critical CO2 Flow Measurements and Visualization

    NASA Astrophysics Data System (ADS)

    Kazemifar, Farzan; Kyritsis, Dimitrios

    2012-11-01

    Carbon dioxide capturing and sequestration is one of the proposed solutions for reducing greenhouse gas emission. This technique will be used in big industrial plants with very high CO2 emissions. Handling such large flow rates requires high pressure and low temperature (in order to maximize density and minimize volumetric flow rate) which brings us close to the critical point of CO2 at approximately 74 bar and 31°C. This necessitates studying near-critical CO2 flows. In our experiment setup CO2 is compressed to supercritical pressures using a hydraulic accumulator. Pressurized CO2 then flows through the test section, which is a 2-ft long stainless steel tube with ID = 0.084 in. The flow rate is controlled by a needle valve downstream of the test section and the mass flow rate is measured using a coriolis mass flow meter. Temperature and pressure are monitored using two K-type thermocouples and pressure transducers at the inlet and exit of the test section. The pressure difference across the pipe is measured separately using a differential pressure transducer. In another set of experiments, the aforementioned test section is replaced with an optically accessible test section. In this setup high-speed imaging is used to visualize the flow inside the test section. We studied the recorded data in order to identify distinct flow regimes based on pressure drop as a function of pressure, temperature and mass flow rate. Acknowledgements: International Institute for Carbon-Neutral Energy Research (I2CNER).

  18. Quantitative blood flow velocity imaging using laser speckle flowmetry

    PubMed Central

    Nadort, Annemarie; Kalkman, Koen; van Leeuwen, Ton G.; Faber, Dirk J.

    2016-01-01

    Laser speckle flowmetry suffers from a debated quantification of the inverse relation between decorrelation time (τc) and blood flow velocity (V), i.e. 1/τc = αV. Using a modified microcirculation imager (integrated sidestream dark field - laser speckle contrast imaging [SDF-LSCI]), we experimentally investigate on the influence of the optical properties of scatterers on α in vitro and in vivo. We found a good agreement to theoretical predictions within certain limits for scatterer size and multiple scattering. We present a practical model-based scaling factor to correct for multiple scattering in microcirculatory vessels. Our results show that SDF-LSCI offers a quantitative measure of flow velocity in addition to vessel morphology, enabling the quantification of the clinically relevant blood flow, velocity and tissue perfusion. PMID:27126250

  19. Quantitative blood flow velocity imaging using laser speckle flowmetry

    NASA Astrophysics Data System (ADS)

    Nadort, Annemarie; Kalkman, Koen; van Leeuwen, Ton G.; Faber, Dirk J.

    2016-04-01

    Laser speckle flowmetry suffers from a debated quantification of the inverse relation between decorrelation time (τc) and blood flow velocity (V), i.e. 1/τc = αV. Using a modified microcirculation imager (integrated sidestream dark field - laser speckle contrast imaging [SDF-LSCI]), we experimentally investigate on the influence of the optical properties of scatterers on α in vitro and in vivo. We found a good agreement to theoretical predictions within certain limits for scatterer size and multiple scattering. We present a practical model-based scaling factor to correct for multiple scattering in microcirculatory vessels. Our results show that SDF-LSCI offers a quantitative measure of flow velocity in addition to vessel morphology, enabling the quantification of the clinically relevant blood flow, velocity and tissue perfusion.

  20. Visualizing Geophysical Flow Problems with Adaptive Mesh Refinement

    NASA Astrophysics Data System (ADS)

    Sevre, E. O.; Yuen, D. A.; George, D. L.; Lee, S.

    2011-12-01

    Adaptive Mesh Refinement (AMR) is a technique used in software to decompose a computational domain based on the level of refinement necessary for spatial and temporal calculations. Comparing AMR runs to uniform grids allows for an unbounded gain in computational time. In this paper we will look at techniques for visualizing tsunami simulations that were run with AMR using the GeoClaw [Berger2011-1, Berger2011-2] software. Due to the computational efficiency of AMR we have decided to look into techniques for visualization of AMR data. By having good visualization tools for geoscientists more time can be spent interpreting results and analyzing data. Good visualization tools can be adapted easily to work with a variety of output formats, and the goal of this work is to provide a foundation for geoscientists to work with. In the past year GeoClaw has been used to model the 2011 Tohoku tsunami originating off the coast of Sendai Japan and delivering catastrophic damage to the Fukushima power plant. The aftermath of this single geologic event is still making headlines 4 months after the fact [Fackler2011]. GeoClaw utilizes the shallow water equations to model a variety of flows that range from tsunami to floods to landslides and debris flows [George2011]. With the advanced computations provided by AMR it is important for researchers to visualize and understand ways that are meaningful to both scientists and civilians affected by the potential outcomes of the computation. Special visualization techniques can be used to visualize and look at data generated with AMR. By incorporating these techniques into their software geoscientists will be able to harness powerful computational tools, such as GeoClaw, while also maintaining an informative view of their data.

  1. A visual investigation of turbulence in stagnation flow about a circular cylinder

    NASA Technical Reports Server (NTRS)

    Sadeh, W. Z.; Brauer, H. J.

    1978-01-01

    A visual investigation of turbulence in stagnation flow around a circular cylinder was carried out in order to gain a physical insight into the model advocated by the corticity-amplification theory. Motion pictures were taken from three different viewpoints, and a frame by frame examination of selected movie strips was conducted. Qualitative and quantitative analyses of the flow events focused on tracing the temporal and spatial evolution of a cross-vortex tube outlined by the entrained smoke filaments. The visualization supplied evidence verifying: (1) the selective stretching of cross-vortex tubes which is responsible for the amplification of cross vorticity and, hence, of streamwise turbulence; (2) the streamwise tilting of stretched cross-vortex tubes; (3) the existence of a coherent array of vortices near the stagnation zone; (4) the interaction of the amplified vorticity with the body laminar boundary layer; and, (5) the growth of a turbulent boundary layer.

  2. Flow Visualization Study of the F-14 Fighter Aircraft Configuration

    NASA Technical Reports Server (NTRS)

    Lorincz, D. J.

    1980-01-01

    Water tunnel studies were performed to qualitatively define the flow field of the F-14. Particular emphasis was placed on defining the vortex flows generated at high angles of attack. The flow visualization tests were conducted in the Northrop water tunnel using a 1/72 scale model of the F-14 with a wing leading-edge sweep of 20 deg. Flow visualization photographs were obtained for angles of attack up to 55 deg and sideslip angles up to 10 deg. The F-14 model was investigated to determine the vortex flow field development, vortex path, and vortex breakdown characteristics as a function of angle of attack and sideslip. Vortex flows were found to develop on the highly swept glove and on the upper surface of the forebody. At 10 deg of sideslip, the windward glove vortex shifted inboard and broke down farther forward than the leeward glove vortex. This asymmetric breakdown of the vortices in sideslip contributes to a reduction in the lateral stability above 20 deg angle of attack. The initial loss of directional stability is a consequence of the adverse sidewash from the windward vortex and the reduced dynamic pressure at the vertical tails.

  3. Flow visualization study of the HiMAT RPRV

    NASA Technical Reports Server (NTRS)

    Lorincz, D. J.

    1980-01-01

    Water tunnel studies were performed to qualitatively define the flow field of the highly maneuverable aircraft technology remotely piloted research vehicle (HiMAT RPRV). Particular emphasis was placed on defining the vortex flows generated at high angles of attack. The flow visualization tests were conducted in the Northrop water tunnel using a 1/15 scale model of the HiMAT RPRV. Flow visualization photographs were obtained for angles of attack up to 40 deg and sideslip angles up to 5 deg. The HiMAT model was investigated in detail to determine the canard and wing vortex flow field development, vortex paths, and vortex breakdown characteristics as a function of angle of attack and sideslip. The presence of the canard caused the wing vortex to form further outboard and delayed the breakdown of the wing vortex to higher angles of attack. An increase in leading edge camber of the maneuver configuration delayed both the formation and the breakdown of the wing and canard vortices. Additional tests showed that the canard vortex was sensitive to variations in inlet mass flow ratio and canard flap deflection angle.

  4. Blood Flow: Multi-scale Modeling and Visualization (July 2011)

    SciTech Connect

    2011-01-01

    Multi-scale modeling of arterial blood flow can shed light on the interaction between events happening at micro- and meso-scales (i.e., adhesion of red blood cells to the arterial wall, clot formation) and at macro-scales (i.e., change in flow patterns due to the clot). Coupled numerical simulations of such multi-scale flow require state-of-the-art computers and algorithms, along with techniques for multi-scale visualizations. This animation presents early results of two studies used in the development of a multi-scale visualization methodology. The fisrt illustrates a flow of healthy (red) and diseased (blue) blood cells with a Dissipative Particle Dynamics (DPD) method. Each blood cell is represented by a mesh, small spheres show a sub-set of particles representing the blood plasma, while instantaneous streamlines and slices represent the ensemble average velocity. In the second we investigate the process of thrombus (blood clot) formation, which may be responsible for the rupture of aneurysms, by concentrating on the platelet blood cells, observing as they aggregate on the wall of an aneruysm. Simulation was performed on Kraken at the National Institute for Computational Sciences. Visualization was produced using resources of the Argonne Leadership Computing Facility at Argonne National Laboratory.

  5. Human visual cortical responses to specular and matte motion flows

    PubMed Central

    Kam, Tae-Eui; Mannion, Damien J.; Lee, Seong-Whan; Doerschner, Katja; Kersten, Daniel J.

    2015-01-01

    Determining the compositional properties of surfaces in the environment is an important visual capacity. One such property is specular reflectance, which encompasses the range from matte to shiny surfaces. Visual estimation of specular reflectance can be informed by characteristic motion profiles; a surface with a specular reflectance that is difficult to determine while static can be confidently disambiguated when set in motion. Here, we used fMRI to trace the sensitivity of human visual cortex to such motion cues, both with and without photometric cues to specular reflectance. Participants viewed rotating blob-like objects that were rendered as images (photometric) or dots (kinematic) with either matte-consistent or shiny-consistent specular reflectance profiles. We were unable to identify any areas in low and mid-level human visual cortex that responded preferentially to surface specular reflectance from motion. However, univariate and multivariate analyses identified several visual areas; V1, V2, V3, V3A/B, and hMT+, capable of differentiating shiny from matte surface flows. These results indicate that the machinery for extracting kinematic cues is present in human visual cortex, but the areas involved in integrating such information with the photometric cues necessary for surface specular reflectance remain unclear. PMID:26539100

  6. Smartphone based visual and quantitative assays on upconversional paper sensor.

    PubMed

    Mei, Qingsong; Jing, Huarong; Li, You; Yisibashaer, Wuerzha; Chen, Jian; Nan Li, Bing; Zhang, Yong

    2016-01-15

    The integration of smartphone with paper sensors recently has been gain increasing attentions because of the achievement of quantitative and rapid analysis. However, smartphone based upconversional paper sensors have been restricted by the lack of effective methods to acquire luminescence signals on test paper. Herein, by the virtue of 3D printing technology, we exploited an auxiliary reusable device, which orderly assembled a 980nm mini-laser, optical filter and mini-cavity together, for digitally imaging the luminescence variations on test paper and quantitative analyzing pesticide thiram by smartphone. In detail, copper ions decorated NaYF4:Yb/Tm upconversion nanoparticles were fixed onto filter paper to form test paper, and the blue luminescence on it would be quenched after additions of thiram through luminescence resonance energy transfer mechanism. These variations could be monitored by the smartphone camera, and then the blue channel intensities of obtained colored images were calculated to quantify amounts of thiram through a self-written Android program installed on the smartphone, offering a reliable and accurate detection limit of 0.1μM for the system. This work provides an initial demonstration of integrating upconversion nanosensors with smartphone digital imaging for point-of-care analysis on a paper-based platform.

  7. Smartphone based visual and quantitative assays on upconversional paper sensor.

    PubMed

    Mei, Qingsong; Jing, Huarong; Li, You; Yisibashaer, Wuerzha; Chen, Jian; Nan Li, Bing; Zhang, Yong

    2016-01-15

    The integration of smartphone with paper sensors recently has been gain increasing attentions because of the achievement of quantitative and rapid analysis. However, smartphone based upconversional paper sensors have been restricted by the lack of effective methods to acquire luminescence signals on test paper. Herein, by the virtue of 3D printing technology, we exploited an auxiliary reusable device, which orderly assembled a 980nm mini-laser, optical filter and mini-cavity together, for digitally imaging the luminescence variations on test paper and quantitative analyzing pesticide thiram by smartphone. In detail, copper ions decorated NaYF4:Yb/Tm upconversion nanoparticles were fixed onto filter paper to form test paper, and the blue luminescence on it would be quenched after additions of thiram through luminescence resonance energy transfer mechanism. These variations could be monitored by the smartphone camera, and then the blue channel intensities of obtained colored images were calculated to quantify amounts of thiram through a self-written Android program installed on the smartphone, offering a reliable and accurate detection limit of 0.1μM for the system. This work provides an initial demonstration of integrating upconversion nanosensors with smartphone digital imaging for point-of-care analysis on a paper-based platform. PMID:26356763

  8. Decoding complex flow-field patterns in visual working memory.

    PubMed

    Christophel, Thomas B; Haynes, John-Dylan

    2014-05-01

    There has been a long history of research on visual working memory. Whereas early studies have focused on the role of lateral prefrontal cortex in the storage of sensory information, this has been challenged by research in humans that has directly assessed the encoding of perceptual contents, pointing towards a role of visual and parietal regions during storage. In a previous study we used pattern classification to investigate the storage of complex visual color patterns across delay periods. This revealed coding of such contents in early visual and parietal brain regions. Here we aim to investigate whether the involvement of visual and parietal cortex is also observable for other types of complex, visuo-spatial pattern stimuli. Specifically, we used a combination of fMRI and multivariate classification to investigate the retention of complex flow-field stimuli defined by the spatial patterning of motion trajectories of random dots. Subjects were trained to memorize the precise spatial layout of these stimuli and to retain this information during an extended delay. We used a multivariate decoding approach to identify brain regions where spatial patterns of activity encoded the memorized stimuli. Content-specific memory signals were observable in motion sensitive visual area MT+ and in posterior parietal cortex that might encode spatial information in a modality independent manner. Interestingly, we also found information about the memorized visual stimulus in somatosensory cortex, suggesting a potential crossmodal contribution to memory. Our findings thus indicate that working memory storage of visual percepts might be distributed across unimodal, multimodal and even crossmodal brain regions.

  9. Quantitative magnetic resonance flow and diffusion imaging in porous media.

    PubMed

    Rajanayagam, V; Yao, S; Pope, J M

    1995-01-01

    Quantitative flow and diffusion measurements have been made for water in model porous media, using magnetic resonance micro-imaging methods. The samples consisted of compacted glass beads of various sizes down to 1 mm diameter. Typical flow and diffusion images exhibited a spatial resolution of 117 microns x 117 microns and velocities in the range 1-2 mm/s. Comparison of volume flow rates calculated from the flow velocity maps with values measured directly yielded good agreement in all cases. There was also good agreement between the mean diffusion coefficient of water calculated from the diffusion maps and the bulk diffusion coefficient for pure water at the same temperature. In addition, the mean diffusion coefficient did not depend on the pore sizes in the bead diameter range of 1-3 mm. Our results also show that partial volume effects can be compensated by appropriate thresholding of the images prior to the final Fourier transformation in the flow-encoding dimension.

  10. A comparative flow visualization study of thermocapillary flow in drops in liquid-liquid systems

    NASA Technical Reports Server (NTRS)

    Balasubramaniam, R.; Rashidnia, N.

    1991-01-01

    Experiments are performed to visualize thermocapillary flow in drops in an immiscible host liquid. The host liquid used is silicone oil. Drops of three different liquids are used, viz, vegetable oil, water-methanol mixture anad pure methanol. Clear evidence of thermocapillary flow is seen in vegetable oil drops. For a mixture of water and methanol (approximately 50-50 by weight), natural convection is seen to dominate the flow outside the drop. Pure methanol drops exhibit thermocapillary flow, but dissolve in silicone oil. A small amount of water added to pure methanol significantly reduces the dissolution. Flow oscillations occur in this system for both isothermal and non-isothermal conditions.

  11. Self-synchronizing Schlieren photography and interferometry for the visualization of unsteady transonic flows

    NASA Technical Reports Server (NTRS)

    Kadlec, R.

    1979-01-01

    The use of self synchronizing stroboscopic Schlieren and laser interferometer systems to obtain quantitative space time measurements of distinguished flow surfaces, steakline patterns, and the density field of two dimensional flows that exhibit a periodic content was investigated. A large field single path stroboscopic Schlieren system was designed, constructed and successfully applied to visualize four periodic flows: near wake behind an oscillating airfoil; edge tone sound generation; 2-D planar wall jet; and axisymmetric pulsed sonic jet. This visualization technique provides an effective means of studying quasi-periodic flows in real time. The image on the viewing screen is a spatial signal average of the coherent periodic motion rather than a single realization, the high speed motion of a quasi-periodic flow can be reconstructed by recording photographs of the flow at different fixed time delays in one cycle. The preliminary design and construction of a self synchronizing stroboscopic laser interferometer with a modified Mach-Zehnder optical system is also reported.

  12. Application of Neutron Radiography to Flow Visualization in Supercritical Water

    NASA Astrophysics Data System (ADS)

    Takenaka, N.; Sugimoto, K.; Takami, S.; Sugioka, K.; Tsukada, T.; Adschiri, T.; Saito, Y.

    Supercritical water is used in various chemical reaction processes including hydrothermal synthesis of metal oxide nano-particles, oxidation, chemical conversion of biomass and plastics. Density of the super critical water is much less than that of the sub-critical water. By using neutron radiography, Peterson et al. have studied salt precipitation processes in supercritical water and the flow pattern in a reverse-flow vessel for salt precipitation, and Balasko et al. have revealed the behaviour of supercritical water in a container. The nano-particles were made by mixing the super critical flow and the sub critical water solution. In the present study, neutron radiography was applied to the flow visualization of the super and sub critical water mixture in a T-junction made of stainless steel pipes for high pressure and temperature conditions to investigate their mixing process. Still images by a CCD camera were obtained by using the neutron radiography system at B4 port in KUR.

  13. Heat transfer and flow visualization of swirling impinging jets

    SciTech Connect

    Huang, L.; El-Genk, M.S.

    1996-12-31

    The heat transfer performance of swirling impinging jets was experimentally investigated, and the flow fields were visualized for a jet diameter, d{sub j} = 12.7 mm and swirl angles, {theta} = 15{degree}, 30{degree}, and 45{degree}. Other experimental parameters included Reynolds number, Re = 3,620--17,600, vertical jet spacing, h = 12.7--76.2 mm, and radial distance from the stagnation point, r = 0--65 mm. The results showed significant enhancement in the heat transfer coefficient, both with respect to radial uniformity and local values, compared to a circular straight impinging jet of the same dimensions at the same test conditions. The flow field visualizations confirmed the measured enhancement in the heat transfer coefficient for the swirling jets as well as the radial distribution of local Nusselt number.

  14. Recent Advances in Visualizing 3D Flow with LIC

    NASA Technical Reports Server (NTRS)

    Interrante, Victoria; Grosch, Chester

    1998-01-01

    Line Integral Convolution (LIC), introduced by Cabral and Leedom in 1993, is an elegant and versatile technique for representing directional information via patterns of correlation in a texture. Although most commonly used to depict 2D flow, or flow over a surface in 3D, LIC methods can equivalently be used to portray 3D flow through a volume. However, the popularity of LIC as a device for illustrating 3D flow has historically been limited both by the computational expense of generating and rendering such a 3D texture and by the difficulties inherent in clearly and effectively conveying the directional information embodied in the volumetric output textures that are produced. In an earlier paper, we briefly discussed some of the factors that may underlie the perceptual difficulties that we can encounter with dense 3D displays and outlined several strategies for more effectively visualizing 3D flow with volume LIC. In this article, we review in more detail techniques for selectively emphasizing critical regions of interest in a flow and for facilitating the accurate perception of the 3D depth and orientation of overlapping streamlines, and we demonstrate new methods for efficiently incorporating an indication of orientation into a flow representation and for conveying additional information about related scalar quantities such as temperature or vorticity over a flow via subtle, continuous line width and color variations.

  15. Flow pattern visualization in a mimic anaerobic digester using CFD.

    PubMed

    Vesvikar, Mehul S; Al-Dahhan, Muthanna

    2005-03-20

    Three-dimensional steady-state computational fluid dynamics (CFD) simulations were performed in mimic anaerobic digesters to visualize their flow pattern and obtain hydrodynamic parameters. The mixing in the digester was provided by sparging gas at three different flow rates. The gas phase was simulated with air and the liquid phase with water. The CFD results were first evaluated using experimental data obtained by computer automated radioactive particle tracking (CARPT). The simulation results in terms of overall flow pattern, location of circulation cells and stagnant regions, trends of liquid velocity profiles, and volume of dead zones agree reasonably well with the experimental data. CFD simulations were also performed on different digester configurations. The effects of changing draft tube size, clearance, and shape of the tank bottoms were calculated to evaluate the effect of digester design on its flow pattern. Changing the draft tube clearance and height had no influence on the flow pattern or dead regions volume. However, increasing the draft tube diameter or incorporating a conical bottom design helped in reducing the volume of the dead zones as compared to a flat-bottom digester. The simulations showed that the gas flow rate sparged by a single point (0.5 cm diameter) sparger does not have an appreciable effect on the flow pattern of the digesters at the range of gas flow rates used. PMID:15685599

  16. Visualization of three-dimensional liquid flow on sieve trays

    NASA Astrophysics Data System (ADS)

    Wang, Xiaoling

    2004-03-01

    This paper presents the simulated result of three-dimensional liquid velocity profile on sieve trays by using a computational flow dynamics (CFD) model with considerations of volume fraction of gas and liquid and the interfacial forces. The Κ-ɛ equation is used for the closure of basic equations. For the first time the three-dimensional liquid flow on a distillation column with ten trays under total reflux is visualized. The simulation was carried out with an Origin 200 Server Workstation of SGI Company using Star-CD V3.1 program. Simulation provides the detailed information of the distribution of 3D liquid velocity on the distillation column.

  17. Instantaneous planar visualization of reacting supersonic flows using silane seeding

    NASA Technical Reports Server (NTRS)

    Smith, Michael W.; Northam, G. B.

    1991-01-01

    A new visualization technique for reacting flows has been developed. This technique, which is suitable for supersonic combustion flows, has been demonstrated on a scramjet combustor model. In this application, gaseous silane (SiH4) was added to the primary hydrogen fuel. When the fuel reacted, so did the (SiH4), producing silica (SiO2) particles in situ. The particles were illuminated with a laser sheet formed from a frequency-doubled Nd:YAG laser (532 nm) beam and the Mie scattering signal was imaged. These planar images of the silica Mie scattering provided instantaneous 'maps' of combustion progress within the turbulent reacting flowfield.

  18. Methods of Visually Determining the Air Flow Around Airplanes

    NASA Technical Reports Server (NTRS)

    Gough, Melvin N; Johnson, Ernest

    1932-01-01

    This report describes methods used by the National Advisory Committee for Aeronautics to study visually the air flow around airplanes. The use of streamers, oil and exhaust gas streaks, lampblack and kerosene, powdered materials, and kerosene smoke is briefly described. The generation and distribution of smoke from candles and from titanium tetrachloride are described in greater detail because they appear most advantageous for general application. Examples are included showing results of the various methods.

  19. Holographic flow visualization of time-varying shock waves

    NASA Technical Reports Server (NTRS)

    Decker, A. J.

    1981-01-01

    Rapid-double-exposure, diffuse-illumination holography is evaluated analytically and experimentally as a flow visualization method for time-varying shock waves. Conditions are determined that minimize the distance (localization error) between the surface or curve of interference-fringe localization and the shock surface. Treated specifically are the cases of shock waves in a transonic compressor rotor for which there is laser anemometer data for comparison and shock waves in a flutter cascade.

  20. Flow Visualization around a Simplified Two-Wheel Landing Gear

    NASA Astrophysics Data System (ADS)

    Ekmekci, Alis; Feltham, Graham

    2013-11-01

    The flow topology around a simplified two-wheel landing gear model is investigated experimentally by employing the hydrogen bubble flow visualization technique in a recirculating water channel. The landing gear test model consists of two identical wheels, an axle, a main strut and a support strut. The flow Reynolds number based on wheel diameter is 31,500 and wheels with varying geometric details are considered. Flow structures have been identified through analysis of long-time video recordings and linked to the model geometry. In the flow region above the wheels (wing side), the flow in the inter-wheel region either separates prematurely from the inner surfaces of the wheels and forms slant vortices in the near-wake, or remains attached till the aft wheel perimeter. Inclusion of interior wheel wells are found to result in a jet-like ejection as a result of the interaction with the axle and main strut. In the flow region below the wheels (ground side) the near wake contains periodically forming, complex, large-scale structures.

  1. MoFlow: visualizing conformational changes in molecules as molecular flow improves understanding

    PubMed Central

    2015-01-01

    Background Current visualizations of molecular motion use a Timeline-analogous representation that conveys "first the molecule was shaped like this, then like this...". This scheme is orthogonal to the Pathline-like human understanding of motion "this part of the molecule moved from here to here along this path". We present MoFlow, a system for visualizing molecular motion using a Pathline-analogous representation. Results The MoFlow system produces high-quality renderings of molecular motion as atom pathlines, as well as interactive WebGL visualizations, and 3D printable models. In a preliminary user study, MoFlow representations are shown to be superior to canonical representations for conveying molecular motion. Conclusions Pathline-based representations of molecular motion are more easily understood than timeline representations. Pathline representations provide other advantages because they represent motion directly, rather than representing structure with inferred motion. PMID:26361501

  2. Image based quantitative reader for Lateral flow immunofluorescence assay.

    PubMed

    Chowdhury, Kaushik Basak; Joseph, Jayaraj; Sivaprakasam, Mohanasankar

    2015-08-01

    Fluorescence Lateral flow immunoassays (LFIA) have wide range of applications in point-of-care testing (POCT). An integrated, motion-free, accurate, reliable reader that performs automated quantitative analysis of LFIA is essential for POCT diagnosis. We demonstrate an image based quantitative method to read the lateral flow immunofluorescence test strips. The developed reader uses line laser diode module to illuminate the LFIA test strip having fluorescent dye. Fluorescence light coming from the region of interest (ROI) of the LFIA test strip was filtered using an emission filter and imaged using a camera following which images were processed in computer. A dedicated control program was developed that automated the entire process including illumination of the test strip using laser diode, capturing the ROI of the test strip, processing and analyzing the images and displaying of results. Reproducibility of the reader has been evaluated using few reference cartridges and HbA1c (Glycated haemoglobin) test cartridges. The proposed system can be upgraded to a compact reader for widespread testing of LFIA test strips. PMID:26736487

  3. Animating streamlines with repeated asymmetric patterns for steady flow visualization

    NASA Astrophysics Data System (ADS)

    Yeh, Chih-Kuo; Liu, Zhanping; Lee, Tong-Yee

    2012-01-01

    Animation provides intuitive cueing for revealing essential spatial-temporal features of data in scientific visualization. This paper explores the design of Repeated Asymmetric Patterns (RAPs) in animating evenly-spaced color-mapped streamlines for dense accurate visualization of complex steady flows. We present a smooth cyclic variable-speed RAP animation model that performs velocity (magnitude) integral luminance transition on streamlines. This model is extended with inter-streamline synchronization in luminance varying along the tangential direction to emulate orthogonal advancing waves from a geometry-based flow representation, and then with evenly-spaced hue differing in the orthogonal direction to construct tangential flow streaks. To weave these two mutually dual sets of patterns, we propose an energy-decreasing strategy that adopts an iterative yet efficient procedure for determining the luminance phase and hue of each streamline in HSL color space. We also employ adaptive luminance interleaving in the direction perpendicular to the flow to increase the contrast between streamlines.

  4. Visualization of two-fluid flows of superfluid helium-4.

    PubMed

    Guo, Wei; La Mantia, Marco; Lathrop, Daniel P; Van Sciver, Steven W

    2014-03-25

    Cryogenic flow visualization techniques have been proved in recent years to be a very powerful experimental method to study superfluid turbulence. Micron-sized solid particles and metastable helium molecules are specifically being used to investigate in detail the dynamics of quantum flows. These studies belong to a well-established, interdisciplinary line of inquiry that focuses on the deeper understanding of turbulence, one of the open problem of modern physics, relevant to many research fields, ranging from fluid mechanics to cosmology. Progress made to date is discussed, to highlight its relevance to a wider scientific community, and future directions are outlined. The latter include, e.g., detailed studies of normal-fluid turbulence, dissipative mechanisms, and unsteady/oscillatory flows.

  5. Flow Visualization Proposed for Vacuum Cleaner Nozzle Designs

    NASA Technical Reports Server (NTRS)

    2005-01-01

    In 1995, the NASA Lewis Research Center and the Kirby Company (a major vacuum cleaner company) began negotiations for a Space Act Agreement to conduct research, technology development, and testing involving the flow behavior of airborne particulate flow behavior. Through these research efforts, we hope to identify ways to improve suction, flow rate, and surface agitation characteristics of nozzles used in vacuum cleaner nozzles. We plan to apply an advanced visualization technology, known as Stereoscopic Imaging Velocimetry (SIV), to a Kirby G-4 vacuum cleaner. Resultant data will be analyzed with a high-speed digital motion analysis system. We also plan to evaluate alternative vacuum cleaner nozzle designs. The overall goal of this project is to quantify both velocity fields and particle trajectories throughout the vacuum cleaner nozzle to optimize its "cleanability"--its ability to disturb and remove embedded dirt and other particulates from carpeting or hard surfaces. Reference

  6. Multi-colored layers for visualizing aerodynamic flow effects

    NASA Technical Reports Server (NTRS)

    Jensen, Ronald N. (Inventor)

    1991-01-01

    A method is provided for visualizing aerodynamic flow effects on a test surface. First, discrete quantities of a sublimating chemical such as naphthalene are distinctively colored via appropriate dyes or paints. Next, a uniform layer of the sublimating chemical having a particular color is applied to the test surface. This layer is covered with a second uniform layer of a different colored sublimating chemical, and so on until a composite of multi-colored layers is formed having a discrete thickness. Friction caused by an airflow results in the distinctly colored layers being removed in proportion to such aerodynamic flow characteristics as velocity and temperature, resulting in a multi-colored portrait which approximates the air flow on the underlying test surface.

  7. A predictor-corrector technique for visualizing unsteady flow

    NASA Technical Reports Server (NTRS)

    Banks, David C.; Singer, Bart A.

    1995-01-01

    We present a method for visualizing unsteady flow by displaying its vortices. The vortices are identified by using a vorticity-predictor pressure-corrector scheme that follows vortex cores. The cross-sections of a vortex at each point along the core can be represented by a Fourier series. A vortex can be faithfully reconstructed from the series as a simple quadrilateral mesh, or its reconstruction can be enhanced to indicate helical motion. The mesh can reduce the representation of the flow features by a factor of one thousand or more compared with the volumetric dataset. With this amount of reduction it is possible to implement an interactive system on a graphics workstation to permit a viewer to examine, in three dimensions, the evolution of the vortical structures in a complex, unsteady flow.

  8. Visualization of two-fluid flows of superfluid helium-4

    PubMed Central

    Guo, Wei; La Mantia, Marco; Lathrop, Daniel P.; Van Sciver, Steven W.

    2014-01-01

    Cryogenic flow visualization techniques have been proved in recent years to be a very powerful experimental method to study superfluid turbulence. Micron-sized solid particles and metastable helium molecules are specifically being used to investigate in detail the dynamics of quantum flows. These studies belong to a well-established, interdisciplinary line of inquiry that focuses on the deeper understanding of turbulence, one of the open problem of modern physics, relevant to many research fields, ranging from fluid mechanics to cosmology. Progress made to date is discussed, to highlight its relevance to a wider scientific community, and future directions are outlined. The latter include, e.g., detailed studies of normal-fluid turbulence, dissipative mechanisms, and unsteady/oscillatory flows. PMID:24704871

  9. Blood Flow: Multi-scale Modeling and Visualization

    SciTech Connect

    2010-01-01

    Multi-scale modeling of arterial blood flow can shed light on the interaction between events happening at micro- and meso-scales (i.e., adhesion of red blood cells to the arterial wall, clot formation) and at macro-scales (i.e., change in flow patterns due to the clot). Coupled numerical simulations of such multi-scale flow require state-of-the-art computers and algorithms. Along with developing methods for multi-scale computations, techniques for multi-scale visualizations must be designed. This animation presents early results of joint efforts of teams from Brown University and Argonne National Laboratory to develop a multi-scale visualization methodology. It illustrates a flow of healthy (red) and diseased (blue) blood cells with a Dissipative Particle Dynamics (DPD) method. Each blood cell is represented by a mesh made of 500 DPD-particles, and small spheres show a sub-set of the DPD particles representing the blood plasma, while instantaneous streamlines and slices represent the ensemble average velocity. Credits: Science: Leopold Grinberg and George Karniadakis, Brown University Visualization: Joseph A. Insley and Michael E. Papka, Argonne National Laboratory This research used resources of the Argonne Leadership Computing Facility at Argonne National Laboratory, which is supported by the Office of Science of the U.S. Department of Energy under contract DE-AC02-06CH11357. This research was supported in part by the National Science Foundation through the PetaApps program and used TeraGrid resources provided by National Institute for Computational Sciences.

  10. Visualization of Internal Flows with Pressure Oscillation and Surface Modification

    NASA Astrophysics Data System (ADS)

    Rivera, Felix; Baker, John

    2009-11-01

    A Stirling engine's displacer piston causes motion in its working fluid that exposes the fluid to pressure oscillations that directly impact flow behavior. Stirling engines are highly efficient external combustion engines that are often used in renewable energy applications and have been identified for use on near space platforms as auxiliary power units. The goal of this study was to identify the basic structures of the transient flow field within the expansion cylinder of a Stirling engine without the added complications introduced by convective heat transfer. A two-dimensional representation of the flow within the expansion cylinder of a Stirling engine was produced using an optically-accessible piston-enclosure configuration. The transient flow field within the enclosure was visualized using a rheoscopic fluid. The Reynolds number, based on the frequency of the piston oscillation and the stroke length, was varied from 1.74 to 9.05. Several transient flow structures are identified and the impact that an array of triangular fins has on these flow structures will be discussed.

  11. Preliminary design of an intermittent smoke flow visualization system

    NASA Technical Reports Server (NTRS)

    Ward, Donald T.; Myatt, James H.

    1993-01-01

    A prototype intermittent flow visualization system that was designed to study vortex flow field dynamics has been constructed and tested through its ground test phase. It produces discrete pulses of dense white smoke consisting of particles of terephthalic acid by the pulsing action of a fast-acting three-way valve. The trajectories of the smoke pulses can be tracked by a video imaging system without intruding in the flow around in flight. Two methods of pulsing the smoke were examined. The simplest and safest approach is to simply divert the smoke between the two outlet ports on the valve; this approach should be particularly effective if it were desired to inject smoke at two locations during the same test event. The second approach involves closing off one of the outlet ports to momentarily block the flow. The second approach requires careful control of valve dwell times to avoid excessive pressure buildup within the cartridge container. This method also increases the velocity of the smoke injected into the flow. The flow of the smoke has been blocked for periods ranging from 30 to 80 milliseconds, depending on the system volume and the length of time the valve is allowed to remain open between valve closings.

  12. Visualization of pulsatile flow for magnetic nanoparticle based therapies

    NASA Astrophysics Data System (ADS)

    Wentzel, Andrew; Yecko, Philip

    2015-11-01

    Pulsatile flow of blood through branched, curved, stenosed, dilated or otherwise perturbed vessels is more complex than flow through a straight, uniform and rigid tube. In some magnetic hyperthermia and magnetic chemo-therapies, localized regions of magnetic nanoparticle laden fluid are deliberately formed in blood vessels and held in place by magnetic fields. The effect of localized magnetic fluid regions on blood flow and the effect of the pulsatile blood flow on such magnetic fluid regions are poorly understood and difficult to examine in vivo or by numerical simulation. We present a laboratory model that facilitates both dye tracer and particle imaging velocimetry (PIV) studies of pulsatile flow of water through semi-flexible tubes in the presence of localized magnetic fluid regions. Results on the visualization of flows over a range of Reynolds and Womersley numbers and for several different (water-based) ferrofluids are compared for straight and curved vessels and for different magnetic localization strategies. These results can guide the design of improved magnetic cancer therapies. Support from the William H. Sandholm Program of Cooper Union's Kanbar Center for Biomedical Engineering is gratefully acknowledged.

  13. #FluxFlow: Visual Analysis of Anomalous Information Spreading on Social Media.

    PubMed

    Zhao, Jian; Cao, Nan; Wen, Zhen; Song, Yale; Lin, Yu-Ru; Collins, Christopher

    2014-12-01

    We present FluxFlow, an interactive visual analysis system for revealing and analyzing anomalous information spreading in social media. Everyday, millions of messages are created, commented, and shared by people on social media websites, such as Twitter and Facebook. This provides valuable data for researchers and practitioners in many application domains, such as marketing, to inform decision-making. Distilling valuable social signals from the huge crowd's messages, however, is challenging, due to the heterogeneous and dynamic crowd behaviors. The challenge is rooted in data analysts' capability of discerning the anomalous information behaviors, such as the spreading of rumors or misinformation, from the rest that are more conventional patterns, such as popular topics and newsworthy events, in a timely fashion. FluxFlow incorporates advanced machine learning algorithms to detect anomalies, and offers a set of novel visualization designs for presenting the detected threads for deeper analysis. We evaluated FluxFlow with real datasets containing the Twitter feeds captured during significant events such as Hurricane Sandy. Through quantitative measurements of the algorithmic performance and qualitative interviews with domain experts, the results show that the back-end anomaly detection model is effective in identifying anomalous retweeting threads, and its front-end interactive visualizations are intuitive and useful for analysts to discover insights in data and comprehend the underlying analytical model. PMID:26356891

  14. #FluxFlow: Visual Analysis of Anomalous Information Spreading on Social Media.

    PubMed

    Zhao, Jian; Cao, Nan; Wen, Zhen; Song, Yale; Lin, Yu-Ru; Collins, Christopher

    2014-12-01

    We present FluxFlow, an interactive visual analysis system for revealing and analyzing anomalous information spreading in social media. Everyday, millions of messages are created, commented, and shared by people on social media websites, such as Twitter and Facebook. This provides valuable data for researchers and practitioners in many application domains, such as marketing, to inform decision-making. Distilling valuable social signals from the huge crowd's messages, however, is challenging, due to the heterogeneous and dynamic crowd behaviors. The challenge is rooted in data analysts' capability of discerning the anomalous information behaviors, such as the spreading of rumors or misinformation, from the rest that are more conventional patterns, such as popular topics and newsworthy events, in a timely fashion. FluxFlow incorporates advanced machine learning algorithms to detect anomalies, and offers a set of novel visualization designs for presenting the detected threads for deeper analysis. We evaluated FluxFlow with real datasets containing the Twitter feeds captured during significant events such as Hurricane Sandy. Through quantitative measurements of the algorithmic performance and qualitative interviews with domain experts, the results show that the back-end anomaly detection model is effective in identifying anomalous retweeting threads, and its front-end interactive visualizations are intuitive and useful for analysts to discover insights in data and comprehend the underlying analytical model.

  15. 3-D Flow Visualization of a Turbulent Boundary Layer

    NASA Astrophysics Data System (ADS)

    Thurow, Brian; Williams, Steven; Lynch, Kyle

    2009-11-01

    A recently developed 3-D flow visualization technique is used to visualize large-scale structures in a turbulent boundary layer. The technique is based on the scanning of a laser light sheet through the flow field similar to that of Delo and Smits (1997). High-speeds are possible using a recently developed MHz rate pulse burst laser system, an ultra-high-speed camera capable of 500,000 fps and a galvanometric scanning mirror yielding a total acquisition time of 136 microseconds for a 220 x 220 x 68 voxel image. In these experiments, smoke is seeded into the boundary layer formed on the wall of a low-speed wind tunnel. The boundary layer is approximately 1.5'' thick at the imaging location with a free stream velocity of 24 ft/s yielding a Reynolds number of 18,000 based on boundary layer thickness. The 3-D image volume is approximately 4'' x 4'' x 4''. Preliminary results using 3-D iso-surface visualizations show a collection of elongated large-scale structures inclined in the streamwise direction. The spanwise width of the structures, which are located in the outer region, is on the order of 25 -- 50% of the boundary layer thickness.

  16. Quantitation of contact allergy in guinea pigs by measuring changes in skin blood flow and skin fold thickness.

    PubMed

    Andersen, K E; Staberg, B

    1985-01-01

    Skin blood flow determined by laser Doppler flowmetry (LDF) and skin fold thickness (SFT) have been used to quantitate allergic contact dermatitis in the guinea pig maximization test (GPMT) using chlorocresol as the allergen. The closed patch test procedure itself influenced both LDF and SFT measurements when determined in 12 sham-treated guinea pigs. The LDF was maximal at 24 hours and the SFT at 48 hours. Before correlating the quantitative measurements with the conventional visual scoring in test and control animals the value from a nearby control site was subtracted from the test site values. The correlations were highly significant (p less than 0.001-0.05) indicating that the quantitative methods were useful supplements to the visual scoring as a measure of interobserver and interlaboratory differences.

  17. Visualizing Time-Varying Phenomena In Numerical Simulations Of Unsteady Flows

    NASA Technical Reports Server (NTRS)

    Lane, David A.

    1996-01-01

    Streamlines, contour lines, vector plots, and volume slices (cutting planes) are commonly used for flow visualization. These techniques are sometimes referred to as instantaneous flow visualization techniques because calculations are based on an instant of the flowfield in time. Although instantaneous flow visualization techniques are effective for depicting phenomena in steady flows,they sometimes do not adequately depict time-varying phenomena in unsteady flows. Streaklines and timelines are effective visualization techniques for depicting vortex shedding, vortex breakdown, and shock waves in unsteady flows. These techniques are examples of time-dependent flow visualization techniques, which are based on many instants of the flowfields in time. This paper describes the algorithms for computing streaklines and timelines. Using numerically simulated unsteady flows, streaklines and timelines are compared with streamlines, contour lines, and vector plots. It is shown that streaklines and timelines reveal vortex shedding and vortex breakdown more clearly than instantaneous flow visualization techniques.

  18. Quantitative Visualization of ChIP-chip Data by Using Linked Views

    SciTech Connect

    Huang, Min-Yu; Weber, Gunther; Li, Xiao-Yong; Biggin, Mark; Hamann, Bernd

    2010-11-05

    Most analyses of ChIP-chip in vivo DNA binding have focused on qualitative descriptions of whether genomic regions are bound or not. There is increasing evidence, however, that factors bind in a highly overlapping manner to the same genomic regions and that it is quantitative differences in occupancy on these commonly bound regions that are the critical determinants of the different biological specificity of factors. As a result, it is critical to have a tool to facilitate the quantitative visualization of differences between transcription factors and the genomic regions they bind to understand each factor's unique roles in the network. We have developed a framework which combines several visualizations via brushing-and-linking to allow the user to interactively analyze and explore in vivo DNA binding data of multiple transcription factors. We describe these visualization types and also provide a discussion of biological examples in this paper.

  19. On the Uses of Full-Scale Schlieren Flow Visualization

    NASA Astrophysics Data System (ADS)

    Settles, G. S.; Miller, J. D.; Dodson-Dreibelbis, L. J.

    2000-11-01

    A lens-and-grid-type schlieren system using a very large grid as a light source was described at earlier APS/DFD meetings. With a field-of-view of 2.3x2.9 m (7.5x9.5 feet), it is the largest indoor schlieren system in the world. Still and video examples of several full-scale airflows and heat-transfer problems visualized thus far will be shown. These include: heating and ventilation airflows, flows due to appliances and equipment, the thermal plumes of people, the aerodynamics of an explosive trace detection portal, gas leak detection, shock wave motion associated with aviation security problems, and heat transfer from live crops. Planned future projects include visualizing fume-hood and grocery display freezer airflows and studying the dispersion of insect repellent plumes at full scale.

  20. Flow visualization study of a vortex-wing interaction

    NASA Technical Reports Server (NTRS)

    Mehta, R. D.; Lim, T. T.

    1984-01-01

    A flow visualization study in water was completed on the interaction of a streamwise vortex with a laminar boundary layer on a two-dimensional wing. The vortex was generated at the tip of a finite wing at incidence, mounted perpendicular to the main wing, and having the same chord as the main wing. The Reynolds number based on wing chord was about 5000. Two different visualization techniques were used. One involved the injection of two different colored dyes into the vortex and the boundary layer. The other technique utilized hydrogen bubbles as an indicator. The position of the vortex was varied in a directional normal to the wing. The angle of attack of the main wing was varied from -5 to +12.5 deg. The vortex induced noticeable cross flows in the wing boundary layer from a distance equivalent to 0.75 chords. When very close to the wing, the vortex entrained boundary layer fluid and caused a cross flow separation which resulted in a secondary vortex.

  1. Quantitative flow phantom for contrast-enhanced breast tomosynthesis

    NASA Astrophysics Data System (ADS)

    Nock, Melissa L.; Kempston, Michael P.; Mainprize, James G.; Yaffe, Martin J.

    2007-03-01

    The use of contrast agents can help to overcome a lack of intrinsic radiographic contrast between malignant and benign breast tissue by taking advantage of the properties of tumour angiogenesis. Studies of contrast-enhanced mammography have demonstrated increased lesion conspicuity and have shown that this technique provides information on contrast uptake kinetics. It has been suggested that malignant and benign lesions can be differentiated in part by their uptake kinetics, so this additional data may lead to more accurate diagnoses. Tomosynthesis is a 3D x-ray imaging technique that permits lesion depth localization and increased conspicuity in comparison with 2D x-ray projection techniques. This modality, used in combination with contrast agents, promises to be a sensitive method of breast cancer detection. To develop the technique of contrast-enhanced breast tomosynthesis, a dynamic flow phantom has been constructed to provide the same types of imaging challenges anticipated in the clinical setting. These challenges include a low-contrast tumour space, relevant temporal contrast agent uptake and washout profiles, and a need for quantitative analysis of enhancement levels. The design of a flow phantom will be presented that includes a dynamic tumour space, a background that masks the tumour space in images without contrast enhancement, and flow characteristics that simulate tumour contrast agent uptake and washout kinetics. The system is calibrated to relate signal to concentration of the contrast agent using a well plate filled with iodinated water. Iodine detectability in the flow phantom is evaluated in terms of the signal-difference-to-noise ratio for various tomosynthesis image acquisition parameters including number of acquired angular views, angular extent, and reconstruction voxel size.

  2. Flow Visualization of Low Prandtl Number Fluids using Electrochemical Measurements

    NASA Technical Reports Server (NTRS)

    Crunkleton, D.; Anderson, T.; Narayanan, R.; Labrosse, G.

    2003-01-01

    It is well established that residual flows exist in contained liquid metal processes. In 1-g processing, buoyancy forces often drive these flows and their magnitudes can be substantial. It is also known that residual flows can exist during microgravity processing, and although greatly reduced in magnitude, they can influence the properties of the processed materials. Unfortunately, there are very few techniques to visualize flows in opaque, high temperature liquid metals, and those available are not easily adapted to flight investigation. In this study, a novel technique is developed that uses liquid tin as the model fluid and solid-state electrochemical cells constructed from Yttria-Stabilized Zirconia (YSZ) to establish and measure dissolved oxygen boundary conditions. The melt serves as a common electrode for each of the electrochemical cells in this design, while independent reference electrodes are maintained at the outside surfaces of the electrolyte. By constructing isolated electrochemical cells at various locations along the container walls, oxygen is introduced or extracted by imposing a known electrical potential or passing a given current between the melt and the reference electrode. This programmed titration then establishes a known oxygen concentration boundary condition at the selected electrolyte-melt interface. Using the other cells, the concentration of oxygen at the electrolyte-melt interface is also monitored by measuring the open-circuit potentials developed between the melt and reference electrodes. Thus the electrochemical cells serve to both establish boundary conditions for the passive tracer and sense its path. Rayleigh-Benard convection was used to validate the electrochemical approach to flow visualization. Thus, a numerical characterization of the second critical Rayleigh numbers in liquid tin was conducted for a variety of Cartesian aspect ratios. The extremely low Prandtl number of tin represents the lowest value studied numerically

  3. A Visualization Study of Secondary Flows in Cascades

    NASA Technical Reports Server (NTRS)

    Herzig, Howard Z; Hansen, Arthur G; Costello, George R

    1954-01-01

    Flow-visualization techniques are employed to ascertain the streamline patterns of the nonpotential secondary flows in the boundary layers of cascades, and thereby to provide a basis for more extended analyses in turbomachines. The three-dimensional deflection of the end-wall boundary layer results in the formation of a vortex within each cascade passage. The size and tightness of the vortex generated depend upon the main-flow turning in the cascade passage. Once formed, a vortex resists turning in subsequent blade rows, with consequent unfavorable angles of attack and possible flow disturbances on the pressure surfaces of subsequent blade rows when the vortices impinge on these surfaces. Two major tip-clearance effects are observed, the formation of a tip-clearance vortex and the scraping effect of a blade with relative motion past the wall boundary layer. The flow patterns indicate methods for improving the blade tip-loading characteristics of compressors and of low- and high-speed turbulence.

  4. Quantitative assessment of emphysema from whole lung CT scans: comparison with visual grading

    NASA Astrophysics Data System (ADS)

    Keller, Brad M.; Reeves, Anthony P.; Apanosovich, Tatiyana V.; Wang, Jianwei; Yankelevitz, David F.; Henschke, Claudia I.

    2009-02-01

    Emphysema is a disease of the lungs that destroys the alveolar air sacs and induces long-term respiratory dysfunction. CT scans allow for imaging of the anatomical basis of emphysema and for visual assessment by radiologists of the extent present in the lungs. Several measures have been introduced for the quantification of the extent of disease directly from CT data in order to add to the qualitative assessments made by radiologists. In this paper we compare emphysema index, mean lung density, histogram percentiles, and the fractal dimension to visual grade in order to evaluate the predictability of radiologist visual scoring of emphysema from low-dose CT scans through quantitative scores, in order to determine which measures can be useful as surrogates for visual assessment. All measures were computed over nine divisions of the lung field (whole lung, individual lungs, and upper/middle/lower thirds of each lung) for each of 148 low-dose, whole lung scans. In addition, a visual grade of each section was also given by an expert radiologist. One-way ANOVA and multinomial logistic regression were used to determine the ability of the measures to predict visual grade from quantitative score. We found that all measures were able to distinguish between normal and severe grades (p<0.01), and between mild/moderate and all other grades (p<0.05). However, no measure was able to distinguish between mild and moderate cases. Approximately 65% prediction accuracy was achieved from using quantitative score to predict visual grade, with 73% if mild and moderate cases are considered as a single class.

  5. Enhanced flow field visualization using a flexible animation procedure

    NASA Astrophysics Data System (ADS)

    Marconi, F.; Moretti, G.; Englund, D. C.

    1989-01-01

    A flexible and powerful procedure for transposing computer-generated images onto video tape is used in flowfield visualization. The result is animated sequences which can be used very effectively in the study of both steady and unsteady flows. The key to the procedure is the fact that the images (i.e., frames) of the animated sequence are recorded on the video tapes one at a time after they are created. Thus, the need for a mass storage system is eliminated because after a frame is recorded it is discarded.

  6. Flow Visualization Techniques for CDF using Volume Rendering

    SciTech Connect

    Crawfis, R.A.; Shen, H-W.; Max, N.

    2000-07-10

    As simulations have migrated towards three-dimensions, new tools for examining the resulting complex datasets have been required. Much progress has been achieved in the area of scientific visualization towards this goal. However, most of the research has focused on the representation and understanding of a single scalar field. Some nice results have been achieved for vector or flow fields. This paper reviews several of these techniques, organizes them by their approach and complexity and presents some observations on their benefits and limitations. Several example images are used to highlight the character of these techniques.

  7. Flow visualization study of the MOD-2 wind turbine wake

    SciTech Connect

    Liu H.T.; Waite, J.W.; Hiester, T.R.; Tacheron, P.H.; Srnsky, R.A.

    1983-06-01

    The specific objectives of the study reported were: to determine the geometry of the MOD-2 wind turbine wake in terms of wake height and width as a function of downstream distance under two conditions of atmospheric stability; to estimate the mean velocity deficit at several downstream stations in the turbine wake; and to investigate the behavior of the rotor-generated vortices, particularly their configuration and persistence. The background of the wake problem is briefly examined, including a discussion of the critical issues that the flow visualization study addresses. Experimental techniques and data analysis methods are described in detail. (LEW)

  8. Enhanced flow field visualization using a flexible animation procedure

    SciTech Connect

    Marconi, F.; Moretti, G.; Englund, D.C.

    1989-01-01

    A flexible and powerful procedure for transposing computer-generated images onto video tape is used in flowfield visualization. The result is animated sequences which can be used very effectively in the study of both steady and unsteady flows. The key to the procedure is the fact that the images (i.e., frames) of the animated sequence are recorded on the video tapes one at a time after they are created. Thus, the need for a mass storage system is eliminated because after a frame is recorded it is discarded. 7 references.

  9. Visualization, Extraction and Quantification of Discontinuities in Compressible Flows

    NASA Technical Reports Server (NTRS)

    Samtaney, Ravi; Morris, R. D.; Cheeseman, P.; Sunelyansky, V.; Maluf, D.; Wolf, D.

    2000-01-01

    Scientific visualizations of two-dimensional compressible flow of a gas with discontinuities are presented. The numerical analogue to experimental techniques such as schlieren imaging, shadowgraphs, and interferograms are discussed. Edge detection techniques are utilized to identify the discontinuities. In particular, the zero crossing of the Laplacian of a field (usually density) is recommended for extracting the discontinuities. An algorithm to extract and quantify the discontinuities is presented. To illustrate the methods developed in the report, the example chosen is that of an unsteady interaction of a shock wave with a contact discontinuity.

  10. Performance of calibration standards for antigen quantitation with flow cytometry.

    PubMed

    Lenkei, R; Gratama, J W; Rothe, G; Schmitz, G; D'hautcourt, J L; Arekrans, A; Mandy, F; Marti, G

    1998-10-01

    In the frame of the activities initiated by the Task Force for Antigen Quantitation of the European Working Group on Clinical Cell Analysis (EWGCCA), an experiment was conducted to evaluate microbead standards used for quantitative flow cytometry (QFCM). An unified window of analysis (UWA) was established on three different instruments (EPICS XL [Coulter Corporation, Miami, FL], FACScan and FACS Calibur [Becton Dickinson, San Jose, CA]) with QC3 microbeads (FCSC, PR). By using this defined fluorescence intensity scale, the performance of several monoclonal antibodies directed to CD3, CD4, and CD8 (conjugated and unconjugated), from three manufacturers (BDIS, Coulter [Immunotech], and DAKO) was tested. In addition, the QIFI system (DAKO) and QuantiBRITE (BDIS), and a method of relative fluorescence intensity (RFI, method of Giorgi), were compared. mAbs reacting with three more antigens, CD16, CD19, and CD38 were tested on the FACScan instrument. Quantitation was carried out using a single batch of cryopreserved peripheral blood leukocytes, and all tests were performed as single color analyses. Significant correlations were observed between the antibody-binding capacity (ABC) values of the same CD antigen measured with various calibrators and with antibodies differing in respect to vendor, labeling and possible epitope recognition. Despite the significant correlations, the ABC values of most monoclonal antibodies differed by 20-40% when determined by the different fluorochrome conjugates and different calibrators. The results of this study indicate that, at the present stage of QFCM consistent ABC values may be attained between laboratories provided that a specific calibration system is used including specific calibrators, reagents, and protocols.

  11. In-Flight Flow Visualization Using Infrared Thermography

    NASA Technical Reports Server (NTRS)

    vanDam, C. P.; Shiu, H. J.; Banks D. W.

    1997-01-01

    The feasibility of remote infrared thermography of aircraft surfaces during flight to visualize the extent of laminar flow on a target aircraft has been examined. In general, it was determined that such thermograms can be taken successfully using an existing airplane/thermography system (NASA Dryden's F-18 with infrared imaging pod) and that the transition pattern and, thus, the extent of laminar flow can be extracted from these thermograms. Depending on the in-flight distance between the F-18 and the target aircraft, the thermograms can have a spatial resolution of as little as 0.1 inches. The field of view provided by the present remote system is superior to that of prior stationary infrared thermography systems mounted in the fuselage or vertical tail of a subject aircraft. An additional advantage of the present experimental technique is that the target aircraft requires no or minimal modifications. An image processing procedure was developed which improves the signal-to-noise ratio of the thermograms. Problems encountered during the analog recording of the thermograms (banding of video images) made it impossible to evaluate the adequacy of the present imaging system and image processing procedure to detect transition on untreated metal surfaces. The high reflectance, high thermal difussivity, and low emittance of metal surfaces tend to degrade the images to an extent that it is very difficult to extract transition information from them. The application of a thin (0.005 inches) self-adhesive insulating film to the surface is shown to solve this problem satisfactorily. In addition to the problem of infrared based transition detection on untreated metal surfaces, future flight tests will also concentrate on the visualization of other flow phenomena such as flow separation and reattachment.

  12. Quantitative assessment of neutrophil phagocytosis using flow cytometry.

    PubMed

    Nordenfelt, Pontus

    2014-01-01

    Neutrophils have an incredible ability to find and eradicate intruders such as bacteria and fungi. They do this largely through the process of phagocytosis, where the target is internalized into a phagosome, and eventually destroyed by the hostile phagosomal environment. It is important to study phagocytosis in order to understand how neutrophils interact with various pathogens and how they respond to different stimuli. Here, I describe a method to study neutrophil phagocytosis of bacteria using flow cytometry. The bacteria are fluorescently labeled before being introduced to neutrophils. After phagocytosis, both any remaining extracellular bacteria and neutrophils are labeled using one-step staining before three-color analysis. To assess phagocytosis, first the average time it takes for the neutrophils to internalize all bound bacteria is determined. Experiments are then performed using that time point while varying the bacteria-to-neutrophil ratio for full control of the analysis. Due to the ease with which multiple samples can be analyzed, and the quantitative nature of flow cytometry, this approach is both reproducible and sensitive.

  13. Computational flow visualization in vibrating flow pump type artificial heart by unstructured grid.

    PubMed

    Kato, Takuma; Kawano, Satoyuki; Nakahashi, Kazuhiro; Yambe, Tomoyuki; Nitta, Shin-ichi; Hashimoto, Hiroyuki

    2003-01-01

    Computational flow visualization in the casing of vibrating flow pump (VFP) was made for various conditions based on the novel techniques of fluid dynamics. VFP type artificial heart can generate the oscillated flow and can be applied to the left ventricular assist device. Flow pattern of blood in an artificial heart is closely connected to mechanical performance and serious biomechanical problems such as hemolysis and blood coagulation. To effectively design the VFP for a left ventricular assist device, the numerical codes for solving Navier-Stokes equations were developed for three-dimensional blood flow based on the finite volume method. Furthermore, the simulation techniques based on the artificial compressibility method and the unstructured grid were also developed here. The numerical calculations were based on the precise configurations and the flow conditions of the prototype device. From the viewpoint of computational fluid dynamics (CFD), the detailed discussion of flow patterns in the casing of VFP, which were closely connected with hemolysis and blood coagulation, was made and the computational results were visualized by the use of the recent technique of computational graphics. Some useful design data of VFP were presented. PMID:12534712

  14. Temperature and pressure measurements at cold exit of counter-flow vortex tube with flow visualization of reversed flow

    NASA Astrophysics Data System (ADS)

    Yusof, Mohd Hazwan bin; Katanoda, Hiroshi; Morita, Hiromitsu

    2015-02-01

    In order to clarify the structure of the cold flow discharged from the counter-flow vortex tube (VT), the temperature and pressure of the cold flow were measured, and the existence and behavior of the reversed flow at the cold exit was studied using a simple flow visualization technique consisting of a 0.75mm-diameter needle, and an oil paint droplet. It is observed through this experiment that the Pitot pressure at the cold exit center can either be lower or higher than atmospheric pressure, depending on the inlet pressure and the cold fraction, and that a reversed flow is observed when the Pitot pressure at the cold exit center is lower than atmospheric pressure. In addition, it is observed that when reducing the cold fraction from unity at any arbitrary inlet pressure, the region of reversed and colder flow in the central part of cold exit extends in the downstream direction.

  15. Scientific Visualization Using the Flow Analysis Software Toolkit (FAST)

    NASA Technical Reports Server (NTRS)

    Bancroft, Gordon V.; Kelaita, Paul G.; Mccabe, R. Kevin; Merritt, Fergus J.; Plessel, Todd C.; Sandstrom, Timothy A.; West, John T.

    1993-01-01

    Over the past few years the Flow Analysis Software Toolkit (FAST) has matured into a useful tool for visualizing and analyzing scientific data on high-performance graphics workstations. Originally designed for visualizing the results of fluid dynamics research, FAST has demonstrated its flexibility by being used in several other areas of scientific research. These research areas include earth and space sciences, acid rain and ozone modelling, and automotive design, just to name a few. This paper describes the current status of FAST, including the basic concepts, architecture, existing functionality and features, and some of the known applications for which FAST is being used. A few of the applications, by both NASA and non-NASA agencies, are outlined in more detail. Described in the Outlines are the goals of each visualization project, the techniques or 'tricks' used lo produce the desired results, and custom modifications to FAST, if any, done to further enhance the analysis. Some of the future directions for FAST are also described.

  16. Soap film flow visualization investigations of oscillating wing energy harvesters

    NASA Astrophysics Data System (ADS)

    Kirschmeier, Benjamin; Bryant, Matthew

    2015-03-01

    With increasing population and proliferation of wireless electronics, significant research attention has turned to harvesting energy from ambient sources such as wind and water flows at scales ranging from micro-watt to mega-watt levels. One technique that has recently attracted attention is the application of bio-inspired flapping wings for energy harvesting. This type of system uses a heaving and pitching airfoil to extract flow energy and generate electricity. Such a device can be realized using passive devices excited by aeroelastic flutter phenomena, kinematic mechanisms driven by mechanical linkages, or semi-active devices that are actively controlled in one degree of freedom and passively driven in another. For these types of systems, numerical simulations have showed strong dependence on efficiency and vortex interaction. In this paper we propose a new apparatus for reproducing arbitrary pitch-heave waveforms to perform flow visualization experiments in a soap film tunnel. The vertically falling, gravity driven soap film tunnel is used to replicate flows with a chord Reynolds number on the order of 4x104. The soap film tunnel is used to investigate leading edge vortex (LEV) and trailing edge vortex (TEV) interactions for sinusoidal and non-sinusoidal waveforms. From a qualitative analysis of the fluid structure interaction, we have been able to demonstrate that the LEVs for non-sinusoidal motion convect faster over the airfoil compared with sinusoidal motion. Signifying that optimal flapping frequency is dependent on the motion profile.

  17. Dual-modality wire-mesh sensor for the visualization of three-phase flows

    NASA Astrophysics Data System (ADS)

    dos Santos, E. N.; Vendruscolo, T. P.; Morales, R. E. M.; Schleicher, E.; Hampel, U.; Da Silva, M. J.

    2015-10-01

    Three-phase gas-liquid-liquid flows are very common in petroleum extraction, production, and transport. In this work a dual-modality measuring technique is introduced which may be well applied for three-phase flow visualization. The measuring principle is based on simultaneous excitation with two distinct frequencies to interrogate each crossing point of a mesh sensor, which in turn are linked to conductive and capacitive parts of fluid impedance. The developed system can operate eight transmitter and eight receiver electrodes at a frame repetition frequency up to 781 Hz. The system has been evaluated by measuring reference components. The overall measurement uncertainty was 8.4%, which considering the fast repetition frequency of measurements is suitable for flow investigation. Furthermore, a model-based method to fuse the data from the dual-modality wire-mesh sensor and to obtain individual phase fraction of gas-oil-water flow is introduced. Here a parametrized model is fitted to the measured conductivity and permittivity distributions enabling one to obtain phase fraction from measured data. The method has been applied and tested to the acquired data from a mesh sensor in static and dynamic three-phase mixtures of gas, oil, and water. Fused images and quantitative values show good agreement with reference values. The newly developed dual-modality wire-mesh sensor has the potential to investigate three-phase flows to a good degree of detail, being a valuable tool to investigate such flows.

  18. Particles for flow visualization and velocimetry in liquid nitrogen

    NASA Astrophysics Data System (ADS)

    Fonda, Enrico; Paoletti, Matthew S.; Sreenivasan, Katepalli R.; Lathrop, Daniel P.

    2010-11-01

    Liquid nitrogen may be used to generate, in a facility of a given size, Reynolds numbers which are substantially larger than that in water because its kinematic viscosity is one fifth that of water at 25^o C. We present a simple technique, previously used in liquid helium [1,2], to create solid tracers for visualization and velocimetry in turbulent liquid nitrogen. These tracers are created by injecting a gaseous mixture of room-temperature nitrogen and an additional gas (element or compound) into the flow. The latter is selected such that, when cooled below 77 K (nitrogen boiling point), it freezes into solid particles with the highest mismatch in the index of refraction and the lowest mismatch in density compared to the surrounding liquid nitrogen. We discuss the formation process of the particles, and characterize the effects of the dilution ratio and gas selection on their size, brightness and fidelity. Possibilities of using this technique for fluid dynamics experiments that require visualization of high Reynolds number flows are reviewed. [1] G. P. Bewley, D. P. Lathrop, and K. R. Sreenivasan, Nature 441, 588 (2006). [2] M. S. Paoletti, R. B. Fiorito, K. R. Sreenivasan, and D. P. Lathrop, J. Phys. Soc. Jpn. 77, 111007 (2008).

  19. Hemodynamic flow visualization of early embryonic great vessels using μPIV.

    PubMed

    Goktas, Selda; Chen, Chia-Yuan; Kowalski, William J; Pekkan, Kerem

    2015-01-01

    Microparticle image velocimetry (μPIV) is an evolving quantitative methodology to closely and accurately monitor the cardiac flow dynamics and mechanotransduction during vascular morphogenesis. While PIV technique has a long history, contemporary developments in advanced microscopy have significantly expanded its power. This chapter includes three new methods for μPIV acquisition in selected embryonic structures achieved through advanced optical imaging: (1) high-speed confocal scanning of transgenic zebrafish embryos, where the transgenic erythrocytes act as the tracing particles; (2) microinjection of artificial seeding particles in chick embryos visualized with stereomicroscopy; and (3) real-time, time-resolved optical coherence tomography acquisition of vitelline vessel flow profiles in chick embryos, tracking the erythrocytes.

  20. Flow Visualization by Elastic Light Scattering in the Boundary Layer of a Supersonic Flow

    NASA Technical Reports Server (NTRS)

    Herring, G. C.; Hillard, Mervin E., Jr.

    2000-01-01

    We demonstrate instantaneous flow visualization of the boundary layer region of a Mach 2.5 supersonic flow over a flat plate that is interacting with an impinging shock wave. Tests were performed in the Unitary Plan Wind Tunnel (UPWT) at NASA Langley Research Center. The technique is elastic light scattering using 10-nsec laser pulses at 532 nm. We emphasize that no seed material of any kind, including water (H2O), is purposely added to the flow. The scattered light comes from a residual impurity that normally exists in the flow medium after the air drying process. Thus, the technique described here differs from the traditional vapor-screen method, which is typically accomplished by the addition of extra H2O vapor to the airflow. The flow is visualized with a series of thin two-dimensional light sheets (oriented perpendicular to the streamwise direction) that are located at several positions downstream of the leading edge of the model. This geometry allows the direct observation of the unsteady flow structure in the spanwise dimension of the model and also allows the indirect observation of the boundary layer growth in the streamwise dimension.

  1. Virtual and Experimental Visualization of Flows in Packed Beds of Spheres Simulating Porous Media Flows

    NASA Technical Reports Server (NTRS)

    Hendricks, R. C.; Athavale, M. M.; Lattime, S. B.; Braun, M. J.

    1998-01-01

    A videotape presentation of flow in a packed bed of spheres is provided. The flow experiment consisted of three principal elements: (1) an oil tunnel 76.2 mm by 76.2 mm in cross section, (2) a packed bed of spheres in regular and irregular arrays, and (3) a flow characterization methodology, either (a) full flow field tracking (FFFT) or (b) computational fluid dynamic (CFD) simulation. The refraction indices of the oil and the test array of spheres were closely matched, and the flow was seeded with aluminum oxide particles. Planar laser light provided a two-dimensional projection of the flow field, and a traverse simulated a three-dimensional image of the entire flow field. Light focusing and reflection rendered the spheres black, permitting visualization of the planar circular interfaces in both the axial and transverse directions. Flows were observed near the wall-sphere interface and within the set of spheres. The CFD model required that a representative section of a packed bed be formed and gridded, enclosing and cutting six spheres so that symmetry conditions could be imposed at all cross-boundaries. Simulations had to be made with the flow direction at right angles to that used in the experiments, however, to take advantage of flow symmetry. Careful attention to detail was required for proper gridding. The flow field was three-dimensional and complex to describe, yet the most prominent finding was flow threads, as computed in the representative 'cube' of spheres with face symmetry and conclusively demonstrated experimentally herein. Random packing and bed voids tended to disrupt the laminar flow, creating vortices.

  2. Microscale flow visualization of nucleate boiling in small channels: Mechanisms influencing heat transfer

    SciTech Connect

    Kasza, K.E.; Didascalou, T.; Wambsganss, M.W.

    1997-07-01

    This paper describes the use of a new test apparatus employing flow visualization via ultra-high-speed video and microscope optics to study microscale nucleate boiling in a small, rectangular, heated channel. The results presented are for water. Because of confinement effects produced by the channel cross section being of the same nominal size as the individual vapor bubbles nucleating at discrete wall sites, flow regimes and heat transfer mechanisms that occur in small channels are shown to be considerably different than those in large channels. Flow visualization data are presented depicting discrete bubble/bubble and bubble/wall interactions for moderate and high heat flux. Quantitative data are also presented on nucleate bubble growth behavior for a single nucleation site in the form of growth rates, bubble sizes, and frequency of generation in the presence and absence of a thin wall liquid layer. Mechanistic boiling behavior and trends are observed which support the use of this type of research as a powerful means to gain fundamental insights into why, under some conditions, nucleate boiling heat transfer coefficients are considerably larger in small channels than in large channels.

  3. Quantitative visualization of alternative exon expression from RNA-seq data

    PubMed Central

    Katz, Yarden; Wang, Eric T.; Silterra, Jacob; Schwartz, Schraga; Wong, Bang; Thorvaldsdóttir, Helga; Robinson, James T.; Mesirov, Jill P.; Airoldi, Edoardo M.; Burge, Christopher B.

    2015-01-01

    Motivation: Analysis of RNA sequencing (RNA-Seq) data revealed that the vast majority of human genes express multiple mRNA isoforms, produced by alternative pre-mRNA splicing and other mechanisms, and that most alternative isoforms vary in expression between human tissues. As RNA-Seq datasets grow in size, it remains challenging to visualize isoform expression across multiple samples. Results: To help address this problem, we present Sashimi plots, a quantitative visualization of aligned RNA-Seq reads that enables quantitative comparison of exon usage across samples or experimental conditions. Sashimi plots can be made using the Broad Integrated Genome Viewer or with a stand-alone command line program. Availability and implementation: Software code and documentation freely available here: http://miso.readthedocs.org/en/fastmiso/sashimi.html Contact: mesirov@broadinstitute.org, airoldi@fas.harvard.edu or cburge@mit.edu Supplementary information: Supplementary data are available at Bioinformatics online. PMID:25617416

  4. Comparison of MSL RCS Jet Computations With Flow Visualization and Velocimetry

    NASA Technical Reports Server (NTRS)

    Johansen, Craig T.; Novak, Luke A.; Bathel, Brett F.; Ashcraft, Scott W.; Danehy, Paul M.

    2012-01-01

    Numerical predictions of the Mars Science Laboratory (MSL) reaction control system (RCS) jets interacting with a Mach 10 hypersonic flow are compared to experimental nitric oxide (NO) planar laser-induced fluorescence (PLIF) data. The steady Reynolds Averaged Navier Stokes (RANS) equations using the Baldwin-Barth one-equation turbulence model were solved using the OVERFLOW code. The experimental PLIF data used for comparison consists of qualitative two-dimensional visualization images, qualitative reconstructed three-dimensional flow structures, and quantitative two-dimensional distributions of streamwise velocity. Through modeling of the PLIF signal equation, computational flow images (CFI) were produced and directly compared to the qualitative PLIF data. Post processing of the experimental and simulation data enabled the jet trajectory to be extracted for a more quantitative comparison. The two-dimensional velocity fields were reconstructed through interpolation of a series of single-component velocity profiles. Each distribution of single-component velocity was obtained using molecular tagging velocimetry (MTV). After validating the numerical model, the numerical solution was further examined to gain insight into hypersonic jet-in-crossflow interaction. Future NO-PLIF experiments are proposed based on this analysis.

  5. A simulated dye method for flow visualization with a computational model for blood flow.

    PubMed

    Kim, T; Cheer, A Y; Dwyer, H A

    2004-08-01

    A numerical dye method for the visualization of unsteady three-dimensional flow calculations is introduced by coupling the unsteady convection-diffusion equation to the Navier-Stokes equation for mass and momentum. This system of equations is descretized using a finite volume projection-like algorithm with generalized coordinates and overset grids. A powerful pressure prediction method is used to accelerate the convergence of the Pressure Poisson equation. To demonstrate the visualization technique, blood flow through the aortic arch region and the three main arterial branches is computed using various Womersley numbers. In this technique, parcels of fluid are followed in time as a function of the cardiac cycle without having to track individual particles, which in turn aids us to better understand some important aspects of the three-dimensionality of the developing unsteady flow. Using this numerical dye method we analyze the strength of the cross flow during the cardiac cycle, the relationship between the penetration of blood into the aortic branches from its relative position in the ascending aortic region and the effects of the Womersley parameter. This technique can be very useful in the design and development of stents where the topology of the device would require understanding where the blood emanating from the heart ends up at the end of the cardiac cycle. Moreover, this method could be useful in investigating the influence of flow and geometry on the local introduction of medication.

  6. Visual guidance based on optic flow: a biorobotic approach.

    PubMed

    Franceschini, Nicolas

    2004-01-01

    This paper addresses some basic questions as to how vision links up with action and serves to guide locomotion in both biological and artificial creatures. The thorough knowledge gained during the past five decades on insects' sensory-motor abilities and the neuronal substrates involved has provided us with a rich source of inspiration for designing tomorrow's self-guided vehicles and micro-vehicles, which will be able to cope with unforeseen events on the ground, under water, in the air, in space, on other planets, and inside the human body. Insects can teach us some useful tricks for designing agile autonomous robots. Since constructing a "biorobot" first requires exactly formulating the biological principles presumably involved, it gives us a unique opportunity of checking the soundness and robustness of these principles by bringing them face to face with the real physical world. "Biorobotics" therefore goes one step beyond computer simulation. It leads to experimenting with real physical robots which have to pass the stringent test of the real world. Biorobotics provide us with a new tool, which can help neurobiologists and neuroethologists to identify and investigate worthwhile issues in the field of sensory-motor control. Here we describe some of the visually guided terrestrial and aerial robots we have developed since 1985 on the basis of our biological findings. All these robots behave in response to the optic flow, i.e., they work by measuring the slip speed of the retinal image. Optic flow is sensed on-board by miniature electro-optical velocity sensors. The very principle of these sensors was based on studies in which we recorded the responses of single identified neurons to single photoreceptor stimulation in a model visual system: the fly's compound eye. PMID:15477039

  7. Visual guidance based on optic flow: a biorobotic approach.

    PubMed

    Franceschini, Nicolas

    2004-01-01

    This paper addresses some basic questions as to how vision links up with action and serves to guide locomotion in both biological and artificial creatures. The thorough knowledge gained during the past five decades on insects' sensory-motor abilities and the neuronal substrates involved has provided us with a rich source of inspiration for designing tomorrow's self-guided vehicles and micro-vehicles, which will be able to cope with unforeseen events on the ground, under water, in the air, in space, on other planets, and inside the human body. Insects can teach us some useful tricks for designing agile autonomous robots. Since constructing a "biorobot" first requires exactly formulating the biological principles presumably involved, it gives us a unique opportunity of checking the soundness and robustness of these principles by bringing them face to face with the real physical world. "Biorobotics" therefore goes one step beyond computer simulation. It leads to experimenting with real physical robots which have to pass the stringent test of the real world. Biorobotics provide us with a new tool, which can help neurobiologists and neuroethologists to identify and investigate worthwhile issues in the field of sensory-motor control. Here we describe some of the visually guided terrestrial and aerial robots we have developed since 1985 on the basis of our biological findings. All these robots behave in response to the optic flow, i.e., they work by measuring the slip speed of the retinal image. Optic flow is sensed on-board by miniature electro-optical velocity sensors. The very principle of these sensors was based on studies in which we recorded the responses of single identified neurons to single photoreceptor stimulation in a model visual system: the fly's compound eye.

  8. Space shuttle orbiter flow visualization study. [water tunnel study of vortex flow during atmospheric entry

    NASA Technical Reports Server (NTRS)

    Lorincz, D. J.

    1980-01-01

    The vortex flows generated at subsonic speed during the final portion of atmospheric reentry were defined using a 0.01 scale model of the orbiter in a diagnostic water tunnel. Flow visualization photographs were obtained over an angle-of-attack range to 40 deg and sideslip angles up to 10 deg. The vortex flow field development, vortex path, and vortex breakdown characteristics were determined as a function of angle-of-attack at zero sideslip. Vortex flows were found to develop on the highly swept glove, on the wing, and on the upper surface of the fuselage. No significant asymmetries were observed at zero sideslip in the water tunnel tests. The sensitivity of the upper surface vortex flow fields to variations in sideslip angle was also studied. The vortex formed on the glove remained very stable in position above the wing up through the 10 deg of sideslip tested. There was a change in the vortex lifts under sideslip due to effective change in leading-edge sweep angles. Asymmetric flow separation occurred on the upper surface of the fuselage at small sideslip angles. The influence of vortex flow fields in sideslip on the lateral/ directional characteristics of the orbiter is discussed.

  9. MICROFLUIDIC DEVICES FOR LABEL-FREE AND NON-INSTRUMENTED QUANTITATION OF UNAMPLIFIED NUCLEIC ACIDS BY FLOW DISTANCE MEASUREMENT

    PubMed Central

    Chatterjee, Debolina; Mansfield, Danielle S.; Woolley, Adam T.

    2014-01-01

    Timely biomarker quantitation has potential to improve human health but current methods have disadvantages either in terms of cost and complexity for benchtop instruments, or reduced performance in quantitation and/or multiplexing for point-of-care systems. We previously developed microfluidic devices wherein visually observed flow distances correlated with a model analyte’s concentration.1 Here, we significantly expand over this prior result to demonstrate the measurement of unamplified DNA analogues of microRNAs (miRNAs), biomarkers whose levels can be altered in disease states. We have developed a method for covalently attaching nucleic acid receptors on poly(dimethylsiloxane) microchannel surfaces by silane and cross-linker treatments. We found a flow distance dependence on target concentrations from 10 μg/mL to 10 pg/mL for DNA in both buffer and synthetic urine. Moreover, flow time in addition to flow distance is correlated with target concentration. We also observed longer flow distances for single-base mismatches compared to the target sequence at the same concentration, indicating that our approach can be used to detect point mutations. Finally, experiments with DNA analogues of miRNA biomarkers for kidney disease (mir-200c-3p) and prostate cancer (mir-107) in synthetic urine showed the ability to detect these analytes near clinically relevant levels. Our results demonstrate that these novel microfluidic assays offer a simple route to sensitive, amplification-free nucleic acid quantitation, with strong potential for point-of-care application. PMID:25530814

  10. Experimental characterization of wingtip vortices in the near field using smoke flow visualizations

    NASA Astrophysics Data System (ADS)

    Serrano-Aguilera, J. J.; García-Ortiz, J. Hermenegildo; Gallardo-Claros, A.; Parras, L.; del Pino, C.

    2016-08-01

    In order to predict the axial development of the wingtip vortices strength, an accurate theoretical model is required. Several experimental techniques have been used to that end, e.g. PIV or hot-wire anemometry, but they imply a significant cost and effort. For this reason, we have performed experiments using the smoke-wire technique to visualize smoke streaks in six planes perpendicular to the main stream flow direction. Using this visualization technique, we obtained quantitative information regarding the vortex velocity field by means of Batchelor's model for two chord-based Reynolds numbers, Re_c=3.33× 10^4 and 10^5. Therefore, this theoretical vortex model has been introduced in the integration of ordinary differential equations which describe the temporal evolution of streak lines as function of two parameters: the swirl number, S, and the virtual axial origin, overline{z_0}. We have applied two different procedures to minimize the distance between experimental and theoretical flow patterns: individual curve fitting at six different control planes in the streamwise direction and the global curve fitting which corresponds to all the control planes simultaneously. Both sets of results have been compared with those provided by del Pino et al. (Phys Fluids 23(013):602, 2011b. doi: 10.1063/1.3537791), finding good agreement. Finally, we have observed a weak influence of the Reynolds number on the values S and overline{z_0} at low-to-moderate Re_c. This experimental technique is proposed as a low cost alternative to characterize wingtip vortices based on flow visualizations.

  11. Preliminary design of an intermittent smoke flow visualization system

    NASA Astrophysics Data System (ADS)

    Ward, D. T.; Brandt, S. B.; Myatt, J. H.

    1992-02-01

    A prototype intermittent smoke flow visualization system for studying the flowfield of an aircraft in flight has been constructed and demonstrated. It provides discrete pulses of dense white smoke suitable for video imaging to determine the unsteady vortex core trajectory of fluid elements in a high angle-of-attack flowfield. Two methods of pulsing the smoke were initially investigated: (1) periodically diverting the smoke between two exit ports and (2) completely blocking the smoke flow for short times. System dynamics have been modeled mathematically, data have been collected in a wind tunnel with blockage times up to 80 milliseconds, and the prototype is currently being flown on a general aviation airplane to collect three-dimensional video data. Three different plenum chamber sizes are available. Data collected so far are consistent and repeatable, though care must be taken to provide adequate contrast levels for accurate video resolution. Camera frame rates of at least 180 frames/second and wide angle lenses for the video cameras are needed to acquire meaningful vortex core velocities and accelerations for the general aviation test aircraft installation.

  12. Preliminary design of an intermittent smoke flow visualization system

    NASA Technical Reports Server (NTRS)

    Ward, D. T.; Brandt, S. B.; Myatt, J. H.

    1992-01-01

    A prototype intermittent smoke flow visualization system for studying the flowfield of an aircraft in flight has been constructed and demonstrated. It provides discrete pulses of dense white smoke suitable for video imaging to determine the unsteady vortex core trajectory of fluid elements in a high angle-of-attack flowfield. Two methods of pulsing the smoke were initially investigated: (1) periodically diverting the smoke between two exit ports and (2) completely blocking the smoke flow for short times. System dynamics have been modeled mathematically, data have been collected in a wind tunnel with blockage times up to 80 milliseconds, and the prototype is currently being flown on a general aviation airplane to collect three-dimensional video data. Three different plenum chamber sizes are available. Data collected so far are consistent and repeatable, though care must be taken to provide adequate contrast levels for accurate video resolution. Camera frame rates of at least 180 frames/second and wide angle lenses for the video cameras are needed to acquire meaningful vortex core velocities and accelerations for the general aviation test aircraft installation.

  13. Wind Tunnel Visualization of the Flow Over a Full-Scale F/A-18 Aircraft

    NASA Technical Reports Server (NTRS)

    Lanser, Wendy R.; Botha, Gavin J.; James, Kevin D.; Crowder, James P.; Schmitz, Fredric H. (Technical Monitor)

    1994-01-01

    The proposed paper presents flow visualization performed during experiments conducted on a full-scale F/A-18 aircraft in the 80- by 120-Foot Wind-Tunnel at NASA Ames Research Center. This investigation used both surface and off-surface flow visualization techniques to examine the flow field on the forebody, canopy, leading edge extensions (LEXs), and wings. The various techniques used to visualize the flow field were fluorescent tufts, flow cones treated with reflective material, smoke in combination with a laser light sheet, and a video imaging system. The flow visualization experiments were conducted over an angle of attack range from 20deg to 45deg and over a sideslip range from -10deg to 10deg. The results show regions of attached and separated flow on the forebody, canopy, and wings. Additionally, the vortical flow is clearly visible over the leading-edge extensions, canopy, and wings.

  14. In-flight off-surface flow visualization using infrared imaging

    NASA Technical Reports Server (NTRS)

    Manuel, Gregory S.; Daryabeigi, Kamran; Alderfer, David W.; Obara, Clifford J.

    1991-01-01

    A light test investigation was conducted to evaluate an infrared (IR) imaging technique to visualize off-surface flow phenomena. A single-engine, general-aviation airplane was equipped with an IR imaging system that viewed the region around the left wingtip. Vortical flow at the wingtip was seeded with surfur hexafluoride, a gas with strong infrared absorbing and emitting characteristics. Different terrain and sky backgrounds were evaluated for their effect on IR images of vortical flow. The best IR images were obtained with a clear background. The results of the investigation indicate that IR flow visualization compliments existing smoke generator methods for off-surface flow visualization.

  15. Background-oriented schlieren with natural background for quantitative visualization of open-air explosions

    NASA Astrophysics Data System (ADS)

    Mizukaki, T.; Wakabayashi, K.; Matsumura, T.; Nakayama, K.

    2014-01-01

    This study describes an attempt of quantitative visualization of open-air explosions via the background-oriented schlieren method (BOS). The shock wave propagation curve and overpressure distribution were extracted from the obtained images and compared with the results of the numerical analysis. The potential of extracting the density distribution behind the shock front is also demonstrated. Two open-air explosions were conducted; one with a -kg emulsion explosive and the other with a -kg composition C4 explosive. A high-speed digital video camera was used with a frame rate of and a pixel size of . A natural background, including trees and grass, was used for BOS measurements instead of the random dots used in a laboratory. The overpressure distribution given by the passing shock was estimated from the visualized images. The estimated overpressures agreed with the values recorded by pressure transducers in the test field. The background displacement caused by light diffraction inside the spherical shock waves was in good agreement, except at the shock front. The results shown here suggest that the BOS method for open-air experiments could provide increasingly better quantitative and conventional visualization results with increasing spatial resolution of high-speed cameras.

  16. Selection on quantitative colour variation in Centaurea cyanus: the role of the pollinator's visual system.

    PubMed

    Renoult, J P; Thomann, M; Schaefer, H M; Cheptou, P-O

    2013-11-01

    Even though the importance of selection for trait evolution is well established, we still lack a functional understanding of the mechanisms underlying phenotypic selection. Because animals necessarily use their sensory system to perceive phenotypic traits, the model of sensory bias assumes that sensory systems are the main determinant of signal evolution. Yet, it has remained poorly known how sensory systems contribute to shaping the fitness surface of selected individuals. In a greenhouse experiment, we quantified the strength and direction of selection on floral coloration in a population of cornflowers exposed to bumblebees as unique pollinators during 4 days. We detected significant selection on the chromatic and achromatic (brightness) components of floral coloration. We then studied whether these patterns of selection are explicable by accounting for the visual system of the pollinators. Using data on bumblebee colour vision, we first showed that bumblebees should discriminate among quantitative colour variants. The observed selection was then compared to the selection predicted by psychophysical models of bumblebee colour vision. The achromatic but not the chromatic channel of the bumblebee's visual system could explain the observed pattern of selection. These results highlight that (i) pollinators can select quantitative variation in floral coloration and could thus account for a gradual evolution of flower coloration, and (ii) stimulation of the visual system represents, at least partly, a functional mechanism potentially explaining pollinators' selection on floral colour variants.

  17. Anatomy-Correlated Breast Imaging and Visual Grading Analysis Using Quantitative Transmission Ultrasound™

    PubMed Central

    Iuanow, Elaine; Malik, Bilal; Obuchowski, Nancy A.; Wiskin, James

    2016-01-01

    Objectives. This study presents correlations between cross-sectional anatomy of human female breasts and Quantitative Transmission (QT) Ultrasound, does discriminate classifier analysis to validate the speed of sound correlations, and does a visual grading analysis comparing QT Ultrasound with mammography. Materials and Methods. Human cadaver breasts were imaged using QT Ultrasound, sectioned, and photographed. Biopsies confirmed microanatomy and areas were correlated with QT Ultrasound images. Measurements were taken in live subjects from QT Ultrasound images and values of speed of sound for each identified anatomical structure were plotted. Finally, a visual grading analysis was performed on images to determine whether radiologists' confidence in identifying breast structures with mammography (XRM) is comparable to QT Ultrasound. Results. QT Ultrasound identified all major anatomical features of the breast, and speed of sound calculations showed specific values for different breast tissues. Using linear discriminant analysis overall accuracy is 91.4%. Using visual grading analysis readers scored the image quality on QT Ultrasound as better than on XRM in 69%–90% of breasts for specific tissues. Conclusions. QT Ultrasound provides accurate anatomic information and high tissue specificity using speed of sound information. Quantitative Transmission Ultrasound can distinguish different types of breast tissue with high resolution and accuracy. PMID:27752261

  18. The Visual Display of Quantitative Information; Envisioning Information; Visual Explanations: Images and Quantities, Evidence and Narrative (by Edward R. Tufte)

    NASA Astrophysics Data System (ADS)

    Harris, Harold H.

    1999-02-01

    The Visual Display of Quantitative Information Edward R. Tufte. Graphics Press: Cheshire, CT, 1983. 195 pp. ISBN 0-961-39210-X. 40.00. Envisioning Information Edward R. Tufte. Graphics Press: Cheshire, CT, 1990. 126 pp. ISBN 0-961-39211-8. 48.00. Visual Explanations: Images and Quantities, Evidence and Narrative Edward R. Tufte. Graphics Press: Cheshire, CT, 1997. 156 pp. ISBN 0-9613921-2-6. $45.00. Visual Explanations: Images and Quantities, Evidence and Narrative is the most recent of three books by Edward R. Tufte about the expression of information through graphs, charts, maps, and images. The most important of all the practical advice in these books is found on the first page of the first book, The Visual Display of Quantitative Information. Quantitative graphics should:

    Show the data Induce the viewer to think about the substance rather than the graphical design Avoid distorting what the data have to say Present many numbers in a small space Make large data sets coherent Encourage the eye to compare data Reveal the data at several levels of detail Serve a clear purpose: description, exploration, tabulation, or decoration Be closely integrated with the statistical and verbal descriptions of a data set
    Tufte illustrates these principles through all three books, going to extremes in the care with which he presents examples, both good and bad. He has designed the books so that the reader almost never has to turn a page to see the image, graph, or table that is being described in the text. The books are set in Monotype Bembo, a lead typeface designed so that smaller sizes open the surrounding white space, producing a pleasing balance. Some of the colored pages were put through more than 20 printing steps in order to render the subtle shadings required. The books are printed on heavy paper stock, and the fact that contributing artists, the typeface, the printing company, and the bindery are all credited on one of the back flyleaves is one

  19. Development of Naphthalene PLIF for Making Quantitative Measurements of Ablation Products Transport in Supersonic Flows

    NASA Astrophysics Data System (ADS)

    Combs, Christopher; Clemens, Noel

    2014-11-01

    Ablation is a multi-physics process involving heat and mass transfer and codes aiming to predict ablation are in need of experimental data pertaining to the turbulent transport of ablation products for validation. Low-temperature sublimating ablators such as naphthalene can be used to create a limited physics problem and simulate ablation at relatively low temperature conditions. At The University of Texas at Austin, a technique is being developed that uses planar laser-induced fluorescence (PLIF) of naphthalene to visualize the transport of ablation products in a supersonic flow. In the current work, naphthalene PLIF will be used to make quantitative measurements of the concentration of ablation products in a Mach 5 turbulent boundary layer. For this technique to be used for quantitative research in supersonic wind tunnel facilities, the fluorescence properties of naphthalene must first be investigated over a wide range of state conditions and excitation wavelengths. The resulting calibration of naphthalene fluorescence will be applied to the PLIF images of ablation from a boundary layer plug, yielding 2-D fields of naphthalene mole fraction. These images may help provide data necessary to validate computational models of ablative thermal protection systems for reentry vehicles. Work supported by NASA Space Technology Research Fellowship Program under grant NNX11AN55H.

  20. [Quantitative evaluation of visual gnosis in children with focal brain lesions].

    PubMed

    Pencheva, S; Zaprianova, L

    1983-01-01

    Bearing in mind the opinion of many authors on a great plasticity and interchangeability of the brain cortical functional systems in children the authors have carried out an experiment with 40 children with focal damages of the brain hemispheres, in 20 of whom the right, and in the other 20 the left hemisphere was affected. Use was made of the method of visual gnosis quantitative assessment in the modification of Pencheva and Mavlov (1975). In the children with the focal damages, more or less marked disturbances of the visual gnosis were revealed, however, no statistically significant relationship between the disturbances and the brain side were disclosed. The agnostic disorders were equally frequent in the children of both groups.

  1. Quantitative and visual analysis of white matter integrity using diffusion tensor imaging

    NASA Astrophysics Data System (ADS)

    Liang, Xuwei; Zhuang, Qi; Cao, Ning; Zhang, Jun

    2009-02-01

    A new fiber tract-oriented quantitative and visual analysis scheme using diffusion tensor imaging (DTI) is developed to study the regional micro structural white matter changes along major fiber bundles which may not be effectively revealed by existing methods due to the curved spatial nature of neuronal paths. Our technique is based on DTI tractography and geodesic path mapping, which establishes correspondences to allow cross-subject evaluation of diffusion properties by parameterizing the fiber pathways as a function of geodesic distance. A novel isonodes visualization scheme is proposed to render regional statistical features along the fiber pathways. Assessment of the technique reveals specific anatomical locations along the genu of the corpus callosum paths with significant diffusion property changes in the amnestic mild cognitive impairment subjects. The experimental results show that this approach is promising and may provide a sensitive technique to study the integrity of neuronal connectivity in human brain.

  2. Parallel Computation and Visualization of Three-dimensional, Time-dependent, Thermal Convective Flows

    NASA Technical Reports Server (NTRS)

    Wang, P.; Li, P.

    1998-01-01

    A high-resolution numerical study on parallel systems is reported on three-dimensional, time-dependent, thermal convective flows. A parallel implentation on the finite volume method with a multigrid scheme is discussed, and a parallel visualization systemm is developed on distributed systems for visualizing the flow.

  3. Visual observation and quantitative measurement of the microwave absorbing effect at X band.

    PubMed

    Zhao, L; Chen, X; Ong, C K

    2008-12-01

    We have set up a two-dimensional spatial field mapping system to measure graphically the quasi-free-space electromagnetic wave in a parallel plate waveguide. Our apparatus illustrates a potential application in characterizing the microwave absorbing materials. From the measured mappings of the microwave field, the visualization of spatial physical process and quantitative characterization of reflectivity coefficients can be achieved. This simple apparatus has a remarkable advantage over with conventional testing methods which usually involve huge, expensive anechoic chambers and demand samples of large size. PMID:19123583

  4. Measurements and implications of vortex motions using two flow-visualization techniques

    NASA Technical Reports Server (NTRS)

    Delisi, Donald P.; Greene, George C.

    1990-01-01

    The present comparative study of two different, but complementary flow-visualization techniques, which yield different interpretations of vortex-migration distance and lifetime, gives attention to the difficulty of determining vortex evolution and lifetime from flow-visualization measurements. The techniques involved the release of a fluorescent dye and of neutrally buoyant particles in a water-filled towing tank. Vortices are found to migrate farther, and last longer, when visualized with neutrally buoyant particles rather than with dyes.

  5. Electrophysiological measurement of information flow during visual search

    PubMed Central

    Cosman, Joshua D.; Arita, Jason T.; Ianni, Julianna D.; Woodman, Geoffrey F.

    2016-01-01

    The temporal relationship between different stages of cognitive processing is long-debated. This debate is ongoing, primarily because it is often difficult to measure the time course of multiple cognitive processes simultaneously. We employed a manipulation that allowed us to isolate ERP components related to perceptual processing, working memory, and response preparation, and then examined the temporal relationship between these components while observers performed a visual search task. We found that when response speed and accuracy were equally stressed, our index of perceptual processing ended before both the transfer of information into working memory and response preparation began. However, when we stressed speed over accuracy response preparation began before the completion of perceptual processing or transfer of information into working memory on trials with the fastest reaction times. These findings show that individuals can control the flow of information transmission between stages, either waiting for perceptual processing to be completed before preparing a response or configuring these stages to overlap in time. PMID:26669285

  6. Flight validation of a pulsed smoke flow visualization system

    NASA Technical Reports Server (NTRS)

    Ward, Donald T.; Dorsett, Kenneth M.

    1993-01-01

    A flow visualization scheme, designed to measure vortex fluid dynamics on research aircraft, was validated in flight. Strake vortex trajectories and axial core velocities were determined using pulsed smoke, high-speed video images, and semiautomated image edge detection hardware and software. Smoke was pulsed by using a fast-acting three-way valve. After being redesigned because of repeatedly jamming in flight, the valve shuttle operated flawlessly during the last two tests. A 25-percent scale, Gothic strake was used to generate vortex over the wing of a GA-7 Cougar and was operated at a local angle of attack of 22 degrees and Reynolds number of approximately 7.8 x 10(exp 5)/ft. Maximum axial velocities measured in the vortex core were between 1.75 and 1.95 times the freestream velocity. Analysis of the pulsed smoke system's affect on forebody vortices indicates that the system may reorient the forebody vortex system; however, blowing momentum coefficients normally used will have no appreciable affect on the leading-edge extension vortex system. It is recommended that a similar pulsed smoke system be installed on the F/A-18 High Angle Research Vehicle and that this approach be used to analyze vortex core dynamics during the remainder of its high-angle-of-attack research flights.

  7. EDITORIAL: The 14th International Symposium on Flow Visualization, ISFV14 The 14th International Symposium on Flow Visualization, ISFV14

    NASA Astrophysics Data System (ADS)

    Kim, Kyung Chun; Lee, Sang Joon

    2011-06-01

    The 14th International Symposium on Flow Visualization (ISFV14) was held in Daegu, Korea, on 21-24 June 2010. There were 304 participants from 17 countries. The state of the art in many aspects of flow visualization was presented and discussed, and a total of 243 papers from 19 countries were presented. Two special lectures and four invited lectures, 48 paper sessions and one poster session were held in five session rooms and in a lobby over four days. Among the paper sessions, those on 'biological flows', 'micro/nano fluidics', 'PIV/PTV' and 'compressible and sonic flows' received great attention from the participants of ISFV14. Special events included presentations of 'The Asanuma Award' and 'The Leonardo Da Vinci Award' to prominent contributors. Awards for photos and movies were given to three scientists for their excellence in flow visualizations. Sixteen papers were selected by the Scientific Committee of ISFV14. After the standard peer review process of this journal, six papers were finally accepted for publication. We wish to thank the editors of MST for making it possible to publish this special feature from ISFV14. We also thank the authors for their careful and insightful work and cooperation in the preparation of revised papers. It will be our pleasure if readers appreciate the hot topics in flow visualization research as a result of this special feature. We also hope that the progress in flow visualization will create new research fields. The 15th International Symposium on Flow Visualization will be held in Minsk, Belarus in 2012. We would like to express sincere thanks to the staff at IOP Publishing for their kind support.

  8. Questionnaire-based person trip visualization and its integration to quantitative measurements in Myanmar

    NASA Astrophysics Data System (ADS)

    Kimijiama, S.; Nagai, M.

    2016-06-01

    With telecommunication development in Myanmar, person trip survey is supposed to shift from conversational questionnaire to GPS survey. Integration of both historical questionnaire data to GPS survey and visualizing them are very important to evaluate chronological trip changes with socio-economic and environmental events. The objectives of this paper are to: (a) visualize questionnaire-based person trip data, (b) compare the errors between questionnaire and GPS data sets with respect to sex and age and (c) assess the trip behaviour in time-series. Totally, 345 individual respondents were selected through random stratification to assess person trip using a questionnaire and GPS survey for each. Conversion of trip information such as a destination from the questionnaires was conducted by using GIS. The results show that errors between the two data sets in the number of trips, total trip distance and total trip duration are 25.5%, 33.2% and 37.2%, respectively. The smaller errors are found among working-age females mainly employed with the project-related activities generated by foreign investment. The trip distant was yearly increased. The study concluded that visualization of questionnaire-based person trip data and integrating them to current quantitative measurements are very useful to explore historical trip changes and understand impacts from socio-economic events.

  9. Using Fluorescent Proteins to Visualize and Quantitate Chlamydia Vacuole Growth Dynamics in Living Cells.

    PubMed

    Zuck, Meghan; Feng, Caroline; Hybiske, Kevin

    2015-10-13

    The obligate intracellular bacterium Chlamydia elicits a great burden on global public health. C. trachomatis is the leading bacterial cause of sexually transmitted infection and also the primary cause of preventable blindness in the world. An essential determinant for successful infection of host cells by Chlamydia is the bacterium's ability to manipulate host cell signaling from within a novel, vacuolar compartment called the inclusion. From within the inclusion, Chlamydia acquire nutrients required for their 2-3 day developmental growth, and they additionally secrete a panel of effector proteins onto the cytosolic face of the vacuole membrane and into the host cytosol. Gaps in our understanding of Chlamydia biology, however, present significant challenges for visualizing and analyzing this intracellular compartment. Recently, a reverse-imaging strategy for visualizing the inclusion using GFP expressing host cells was described. This approach rationally exploits the intrinsic impermeability of the inclusion membrane to large molecules such as GFP. In this work, we describe how GFP- or mCherry-expressing host cells are generated for subsequent visualization of chlamydial inclusions. Furthermore, this method is shown to effectively substitute for costly antibody-based enumeration methods, can be used in tandem with other fluorescent labels, such as GFP-expressing Chlamydia, and can be exploited to derive key quantitative data about inclusion membrane growth from a range of Chlamydia species and strains.

  10. Fracturing as a Quantitative Indicator of Lava Flow Dynamics

    NASA Astrophysics Data System (ADS)

    Kilburn, C. R.; Solana, C.

    2005-12-01

    The traditional classification of lava flows into pahoehoe and aa varieties reflects differences in how a flow can fracture its surface during advance. Both types of lava have a low strength upon eruption and require surface cooling to produce a crust that can fracture. Among pahoehoe lavas, applied stresses are small enough to allow the growth of a continuous crust, which is broken intermittently as the flow advances by propagating a collection of lava tongues. Among aa lavas, in contrast, applied stresses are large enough to maintain persistent crustal failure. The differences in fracturing characteristics has been used to quantify the transition between flow regimes and suggests that shear fracture may dominate tensile failure. Applied to Lanzarote, the model confirms the inference from incomplete eye-witness accounts of the 1730-36 Timanfaya eruption that pahoehoe flows were able to advance about an order of magnitude more quickly than would have been expected by analogy with Hawaiian pahoehoe flow-fields of similar dimensions. Surface texture and morphology, therefore, are insufficient guides for constraining the rate and style of pahoehoe emplacement. Applications include improved hazard assessments during effusive eruptions and new evaluations of the emplacement conditions for very large-volume pahoehoe lava flows.

  11. Visualization of heat transfer for impinging swirl flow

    SciTech Connect

    Bakirci, K.; Bilen, K.

    2007-10-15

    The objective of the experimental study was to visualize the temperature distribution and evaluate heat transfer rate on the impingement surface kept at a constant wall temperature boundary condition for the swirling (SIJ), multi-channel (MCIJ) and conventional impinging jet (CIJ) using liquid crystal technique. The swirling jet assembly consisted of a housing tube and a solid swirl generator insert which had four narrow slots machined on its surface. The swirl angle, {theta}, was set as 0 , 22.5 , 41 , 50 to change the direction and strength of the swirl in the air flow exiting the housing tube. The local Nusselt numbers of the MCIJ ({theta} = 0 ) were generally much higher than those of CIJ and SIJs. As the swirl angle increased, the radial uniformity of the heat transfer was seen compared to MCIJ and SIJ; the best results were for {theta} = 50 and the jet-to-surface distance of H/D = 14. The location of the distance of the maximum heat transfer for the swirl angles of {theta} = 41 and 50 was shifted away from the stagnation point in a radial distance of nearly r/D = 2.5. Increasing Reynolds number for same swirler angle increased the heat transfer rate on the entire surface, and increased saddle shape heat transfer distribution on the surface, but had no significant effect on the position of the individual impingement regions, but increased saddle shape heat transfer distribution on the surface. The lower Reynolds number (Re = 10 000) and the highest H/D = 14 gave much more uniform local and average heat transfer distribution on the surface, but decreased their values on the entire surface. (author)

  12. A visual study of radial inward choked flow of liquid nitrogen

    NASA Technical Reports Server (NTRS)

    Hendricks, R. C.; Simoneau, R. J.; Hsu, Y. Y.

    1973-01-01

    A visual study of the radial inward choked flow of liquid nitrogen was conducted. Data and high speed moving pictures were obtained. The study indicated the following: (1) steady radial inward choked flow seems equivalent to steady choked flow through axisymmetric nozzles, (2) transient choked flows through the radial gap are not uniform and the discharge pattern appears as nonuniform impinging jets, and (3) the critical mass flow rate data for the transient case appear different from those of the steady case.

  13. Numerical Simulation and Quantitative Uncertainty Assessment of Microchannel Flow

    NASA Astrophysics Data System (ADS)

    Debusschere, Bert; Najm, Habib; Knio, Omar; Matta, Alain; Ghanem, Roger; Le Maitre, Olivier

    2002-11-01

    This study investigates the effect of uncertainty in physical model parameters on computed electrokinetic flow of proteins in a microchannel with a potassium phosphate buffer. The coupled momentum, species transport, and electrostatic field equations give a detailed representation of electroosmotic and pressure-driven flow, including sample dispersion mechanisms. The chemistry model accounts for pH-dependent protein labeling reactions as well as detailed buffer electrochemistry in a mixed finite-rate/equilibrium formulation. To quantify uncertainty, the governing equations are reformulated using a pseudo-spectral stochastic methodology, which uses polynomial chaos expansions to describe uncertain/stochastic model parameters, boundary conditions, and flow quantities. Integration of the resulting equations for the spectral mode strengths gives the evolution of all stochastic modes for all variables. Results show the spatiotemporal evolution of uncertainties in predicted quantities and highlight the dominant parameters contributing to these uncertainties during various flow phases. This work is supported by DARPA.

  14. Development of Cellular Absorptive Tracers (CATs) for a Quantitative Characterization of Microbial Mass in Flow Systems

    SciTech Connect

    Saripalli, Prasad; Brown, Christopher F.; Lindberg, Michael J.

    2005-03-16

    We report on a new Cellular Absorptive Tracers (CATs) method, for a simple, non-destructive characterization of bacterial mass in flow systems. Results show that adsorption of a CAT molecule into the cellular mass results in its retardation during flow, which is a good, quantitative measure of the biomass quantity and distribution. No such methods are currently available for a quantitative characterization of cell mass.

  15. Three-dimensional flow visualization in the wake of a miniature axial-flow hydrokinetic turbine

    NASA Astrophysics Data System (ADS)

    Chamorro, Leonardo P.; Troolin, Daniel R.; Lee, Seung-Jae; Arndt, R. E. A.; Sotiropoulos, Fotis

    2013-02-01

    Three-dimensional 3-component velocity measurements were made in the near wake region of a miniature 3-blade axial-flow turbine within a turbulent boundary layer. The model turbine was placed in an open channel flow and operated under subcritical conditions (Fr = 0.13). The spatial distribution of the basic flow statistics was obtained at various locations to render insights into the spatial features of the wake. Instantaneous and phase-averaged vortical structures were analyzed to get insights about their dynamics. The results showed a wake expansion proportional to the one-third power of the streamwise distance, within the first rotor diameter. Wake rotation was clearly identified up to a distance of roughly three rotor diameters. In particular, relatively high tangential velocity was observed near the wake core, but it was found to be nearly negligible at the turbine tip radius. In contrast, the radial velocity showed the opposite distribution, with higher radial velocity near the turbine tip and, due to symmetry, negligible at the rotor axis. Larger turbulence intensity was found above the hub height and near the turbine tip. Strong coherent tip vortices, visualized in terms of the instantaneous vorticity and the λ 2 criterion, were observed within the first rotor diameter downstream of the turbine. These structures, influenced by the velocity gradient in the boundary layer, appeared to loose their stability at distances greater than two rotor diameters. Hub vortices were also identified. Measurements did not exhibit significant tip-hub vortex interaction within the first rotor diameter.

  16. Comparison of Diagnostic Performance Between Visual and Quantitative Assessment of Bone Scintigraphy Results in Patients With Painful Temporomandibular Disorder

    PubMed Central

    Choi, Bong-Hoi; Yoon, Seok-Ho; Song, Seung-Il; Yoon, Joon-Kee; Lee, Su Jin; An, Young-Sil

    2016-01-01

    Abstract This retrospective clinical study was performed to evaluate whether a visual or quantitative method is more valuable for assessing painful temporomandibular disorder (TMD) using bone scintigraphy results. In total, 230 patients (172 women and 58 men) with TMD were enrolled. All patients were questioned about their temporomandibular joint (TMJ) pain. Bone scintigraphic data were acquired in all patients, and images were analyzed by visual and quantitative methods using the TMJ-to-skull uptake ratio. The diagnostic performances of both bone scintigraphic assessment methods for painful TMD were compared. In total, 241 of 460 TMJs (52.4%) were finally diagnosed with painful TMD. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of the visual analysis for diagnosing painful TMD were 62.8%, 59.6%, 58.6%, 63.8%, and 61.1%, respectively. The quantitative assessment showed the ability to diagnose painful TMD with a sensitivity of 58.8% and specificity of 69.3%. The diagnostic ability of the visual analysis for diagnosing painful TMD was not significantly different from that of the quantitative analysis. Visual bone scintigraphic analysis showed a diagnostic utility similar to that of quantitative assessment for the diagnosis of painful TMD. PMID:26765456

  17. Quantitative velocity distributions via nuclear magnetic resonance flow metering

    NASA Astrophysics Data System (ADS)

    O'Neill, Keelan T.; Fridjonsson, Einar O.; Stanwix, Paul L.; Johns, Michael L.

    2016-08-01

    We demonstrate the use of Tikhonov regularisation as a data inversion technique to determine the velocity distributions of flowing liquid streams. Regularisation is applied to the signal produced by a nuclear magnetic resonance (NMR) flow measurement system consisting of a pre-polarising permanent magnet located upstream of an Earth's magnetic field NMR detection coil. A simple free induction decay (FID) NMR signal is measured for the flowing stream in what is effectively a 'time-of-flight' measurement. The FID signal is then modelled as a function of fluid velocity and acquisition time, enabling determination of the velocity probability distributions via regularisation. The mean values of these velocity distributions were successfully validated against in-line rotameters. The ability to quantify multi-modal velocity distributions was also demonstrated using a two-pipe system.

  18. Quantitative velocity distributions via nuclear magnetic resonance flow metering.

    PubMed

    O'Neill, Keelan T; Fridjonsson, Einar O; Stanwix, Paul L; Johns, Michael L

    2016-08-01

    We demonstrate the use of Tikhonov regularisation as a data inversion technique to determine the velocity distributions of flowing liquid streams. Regularisation is applied to the signal produced by a nuclear magnetic resonance (NMR) flow measurement system consisting of a pre-polarising permanent magnet located upstream of an Earth's magnetic field NMR detection coil. A simple free induction decay (FID) NMR signal is measured for the flowing stream in what is effectively a 'time-of-flight' measurement. The FID signal is then modelled as a function of fluid velocity and acquisition time, enabling determination of the velocity probability distributions via regularisation. The mean values of these velocity distributions were successfully validated against in-line rotameters. The ability to quantify multi-modal velocity distributions was also demonstrated using a two-pipe system. PMID:27343484

  19. Quantitative velocity distributions via nuclear magnetic resonance flow metering.

    PubMed

    O'Neill, Keelan T; Fridjonsson, Einar O; Stanwix, Paul L; Johns, Michael L

    2016-08-01

    We demonstrate the use of Tikhonov regularisation as a data inversion technique to determine the velocity distributions of flowing liquid streams. Regularisation is applied to the signal produced by a nuclear magnetic resonance (NMR) flow measurement system consisting of a pre-polarising permanent magnet located upstream of an Earth's magnetic field NMR detection coil. A simple free induction decay (FID) NMR signal is measured for the flowing stream in what is effectively a 'time-of-flight' measurement. The FID signal is then modelled as a function of fluid velocity and acquisition time, enabling determination of the velocity probability distributions via regularisation. The mean values of these velocity distributions were successfully validated against in-line rotameters. The ability to quantify multi-modal velocity distributions was also demonstrated using a two-pipe system.

  20. Quantitative framework for preferential flow initiation and partitioning

    USGS Publications Warehouse

    Nimmo, John R.

    2016-01-01

    A model for preferential flow in macropores is based on the short-range spatial distribution of soil matrix infiltrability. It uses elementary areas at two different scales. One is the traditional representative elementary area (REA), which includes a sufficient heterogeneity to typify larger areas, as for measuring field-scale infiltrability. The other, called an elementary matrix area (EMA), is smaller, but large enough to represent the local infiltrability of soil matrix material, between macropores. When water is applied to the land surface, each EMA absorbs water up to the rate of its matrix infiltrability. Excess water flows into a macropore, becoming preferential flow. The land surface then can be represented by a mesoscale (EMA-scale) distribution of matrix infiltrabilities. Total preferential flow at a given depth is the sum of contributions from all EMAs. Applying the model, one case study with multi-year field measurements of both preferential and diffuse fluxes at a specific depth was used to obtain parameter values by inverse calculation. The results quantify the preferential–diffuse partition of flow from individual storms that differed in rainfall amount, intensity, antecedent soil water, and other factors. Another case study provided measured values of matrix infiltrability to estimate parameter values for comparison and illustrative predictions. These examples give a self-consistent picture from the combination of parameter values, directions of sensitivities, and magnitudes of differences caused by different variables. One major practical use of this model is to calculate the dependence of preferential flow on climate-related factors, such as varying soil wetness and rainfall intensity.

  1. Comparison of visualized turbine endwall secondary flows and measured heat transfer patterns

    NASA Technical Reports Server (NTRS)

    Gaugler, R. E.; Russell, L. M.

    1983-01-01

    Various flow visualization techniques were used to define the secondary flows near the endwall in a large heat transfer data. A comparison of the visualized flow patterns and the measured Stanton number distribution was made for cases where the inlet Reynolds number and exit Mach number were matched. Flows were visualized by using neutrally buoyant helium-filled soap bubbles, by using smoke from oil soaked cigars, and by a few techniques using permanent marker pen ink dots and synthetic wintergreen oil. Details of the horseshoe vortex and secondary flows can be directly compared with heat transfer distribution. Near the cascade entrance there is an obvious correlation between the two sets of data, but well into the passage the effect of secondary flow is not as obvious.

  2. Comparison of visualized turbine endwall secondary flows and measured heat transfer patterns

    NASA Astrophysics Data System (ADS)

    Gaugler, R. E.; Russell, L. M.

    1984-01-01

    Various flow visualization techniques were used to define the seondary flows near the endwall in a large heat transfer data. A comparison of the visualized flow patterns and the measured Stanton number distribution was made for cases where the inlet Reynolds number and exit Mach number were matched. Flows were visualized by using neutrally buoyant helium-filled soap bubbles, by using smoke from oil soaked cigars, and by a few techniques using permanent marker pen ink dots and synthetic wintergreen oil. Details of the horseshoe vortex and secondary flows can be directly compared with heat transfer distribution. Near the cascade entrance there is an obvious correlation between the two sets of data, but well into the passage the effect of secondary flow is not as obvious. Previously announced in STAR as N83-14435

  3. Comparison of visualized turbine endwall secondary flows and measured heat transfer patterns

    NASA Astrophysics Data System (ADS)

    Gaugler, R. E.; Russell, L. M.

    1983-03-01

    Various flow visualization techniques were used to define the secondary flows near the endwall in a large heat transfer data. A comparison of the visualized flow patterns and the measured Stanton number distribution was made for cases where the inlet Reynolds number and exit Mach number were matched. Flows were visualized by using neutrally buoyant helium-filled soap bubbles, by using smoke from oil soaked cigars, and by a few techniques using permanent marker pen ink dots and synthetic wintergreen oil. Details of the horseshoe vortex and secondary flows can be directly compared with heat transfer distribution. Near the cascade entrance there is an obvious correlation between the two sets of data, but well into the passage the effect of secondary flow is not as obvious.

  4. Quantitative visualization of DNA G-quadruplex structures in human cells

    NASA Astrophysics Data System (ADS)

    Biffi, Giulia; Tannahill, David; McCafferty, John; Balasubramanian, Shankar

    2013-03-01

    Four-stranded G-quadruplex nucleic acid structures are of great interest as their high thermodynamic stability under near-physiological conditions suggests that they could form in cells. Here we report the generation and application of an engineered, structure-specific antibody employed to quantitatively visualize DNA G-quadruplex structures in human cells. We show explicitly that G-quadruplex formation in DNA is modulated during cell-cycle progression and that endogenous G-quadruplex DNA structures can be stabilized by a small-molecule ligand. Together these findings provide substantive evidence for the formation of G-quadruplex structures in the genome of mammalian cells and corroborate the application of stabilizing ligands in a cellular context to target G-quadruplexes and intervene with their function.

  5. Visualization and quantitative analysis of nanoparticles in the respiratory tract by transmission electron microscopy

    PubMed Central

    Mühlfeld, Christian; Rothen-Rutishauser, Barbara; Vanhecke, Dimitri; Blank, Fabian; Gehr, Peter; Ochs, Matthias

    2007-01-01

    Nanotechnology in its widest sense seeks to exploit the special biophysical and chemical properties of materials at the nanoscale. While the potential technological, diagnostic or therapeutic applications are promising there is a growing body of evidence that the special technological features of nanoparticulate material are associated with biological effects formerly not attributed to the same materials at a larger particle scale. Therefore, studies that address the potential hazards of nanoparticles on biological systems including human health are required. Due to its large surface area the lung is one of the major sites of interaction with inhaled nanoparticles. One of the great challenges of studying particle-lung interactions is the microscopic visualization of nanoparticles within tissues or single cells both in vivo and in vitro. Once a certain type of nanoparticle can be identified unambiguously using microscopic methods it is desirable to quantify the particle distribution within a cell, an organ or the whole organism. Transmission electron microscopy provides an ideal tool to perform qualitative and quantitative analyses of particle-related structural changes of the respiratory tract, to reveal the localization of nanoparticles within tissues and cells and to investigate the 3D nature of nanoparticle-lung interactions. This article provides information on the applicability, advantages and disadvantages of electron microscopic preparation techniques and several advanced transmission electron microscopic methods including conventional, immuno and energy-filtered electron microscopy as well as electron tomography for the visualization of both model nanoparticles (e.g. polystyrene) and technologically relevant nanoparticles (e.g. titanium dioxide). Furthermore, we highlight possibilities to combine light and electron microscopic techniques in a correlative approach. Finally, we demonstrate a formal quantitative, i.e. stereological approach to analyze the

  6. Visualization and Quantification of Rotor Tip Vortices in Helicopter Flows

    NASA Technical Reports Server (NTRS)

    Kao, David L.; Ahmad, Jasim U.; Holst, Terry L.

    2015-01-01

    This paper presents an automated approach for effective extraction, visualization, and quantification of vortex core radii from the Navier-Stokes simulations of a UH-60A rotor in forward flight. We adopt a scaled Q-criterion to determine vortex regions and then perform vortex core profiling in these regions to calculate vortex core radii. This method provides an efficient way of visualizing and quantifying the blade tip vortices. Moreover, the vortices radii are displayed graphically in a plane.

  7. SplicePlot: a utility for visualizing splicing quantitative trait loci

    PubMed Central

    Wu, Eric; Nance, Tracy; Montgomery, Stephen B.

    2014-01-01

    Summary: RNA sequencing has provided unprecedented resolution of alternative splicing and splicing quantitative trait loci (sQTL). However, there are few tools available for visualizing the genotype-dependent effects of splicing at a population level. SplicePlot is a simple command line utility that produces intuitive visualization of sQTLs and their effects. SplicePlot takes mapped RNA sequencing reads in BAM format and genotype data in VCF format as input and outputs publication-quality Sashimi plots, hive plots and structure plots, enabling better investigation and understanding of the role of genetics on alternative splicing and transcript structure. Availability and implementation: Source code and detailed documentation are available at http://montgomerylab.stanford.edu/spliceplot/index.html under Resources and at Github. SplicePlot is implemented in Python and is supported on Linux and Mac OS. A VirtualBox virtual machine running Ubuntu with SplicePlot already installed is also available. Contact: wu.eric.g@gmail.com or smontgom@stanford.edu PMID:24363378

  8. Visual analytics for finding critical structures in massive time-varying turbulent-flow simulations.

    PubMed

    Gaither, Kelly P; Childs, Hank; Schulz, Karl W; Harrison, Cyrus; Barth, William; Donzis, Diego; Yeung, Pui-Kuen

    2012-01-01

    Visualization and data analysis are crucial in analyzing and understanding a turbulent-flow simulation of size 4,096(3) cells per time slice (68 billion cells) and 17 time slices (one trillion total cells). The visualization techniques used help scientists investigate the dynamics of intense events individually and as these events form clusters.

  9. Visualization of Flows in Packed Beds of Twisted Tapes

    NASA Technical Reports Server (NTRS)

    Hendricks, R. C.; Braun, M. J.; Peloso, D.; Athavale, M. M.; Mullen, R. L.

    2002-01-01

    A videotape presentation of the flow field in a packed bed of 48 twisted tapes which can be simulated by very thin virtual cylinders has been assembled. The indices of refraction of the oil and the Lucite twisted tapes were closely matched, and the flow was seeded with magnesium oxide particles. Planar laser light projected the flow field in two dimensions both along and transverse to the flow axis. The flow field was three dimensional and complex to describe, yet the most prominent finding was flow threads. It appeared that axial flow spiraled along either within the confines of a virtual cylindrical boundary or within the exterior region, between the tangency points, of the virtual cylinders. Random packing and bed voids created vortices and disrupted the laminar flow but minimized the entrance effects. The flow-pressure drops in the packed bed fell below the Ergun model for porous-media flows. Single-twisted-tape results of Smithberg and Landis (1964) were used to guide the analysis. In appendix A the results of several investigators are scaled to the Ergun model. Further investigations including different geometric configurations, computational fluid dynamic (CFD) gridding, and analysis are required.

  10. Flow Visualizations in a Packed Bed of Twisted Tapes

    NASA Technical Reports Server (NTRS)

    Hendricks, R. C.; Braun, M. J.

    2002-01-01

    A videotape presentation of the flow field in a packed bed of 48 twisted tapes which can be simulated by very thin virtual cylinders has been assembled. The indices of refraction of the oil and the Lucite twisted tapes were closely matched, and the flow was seeded with magnesium oxide particles. Planar laser light projected the flow field in two dimensions both along and transverse to the flow axis. The flow field was three dimensional and complex to describe, yet the most prominent finding was flow threads. It appeared that axial flow spiraled along either within the confines of a virtual cylindrical boundary or within the exterior region, between the tangency points, of the virtual cylinders. Random packing and bed voids created vortices and disrupted the laminar flow but minimized the entrance effects. The flow-pressure drops in the packed bed fell below the Ergun model for porous-media flows. Single-twisted-tape results of Smithberg and Landis (1964) were used to guide the analysis. In appendix A the results of several investigators are scaled to the Ergun model. Further investigations including different geometric configurations, computational fluid dynamic (CFD) gridding, and analysis are required.

  11. Some flow visualization experiments on the starting vortex

    NASA Astrophysics Data System (ADS)

    Pullin, D. I.; Perry, A. E.

    1980-03-01

    Experiments were performed for studying the development of a two-dimensional starting flow vortex for different edge-forming geometries (wedge angles) and several velocity-time power-law histories of the generating flow. They were carried out in a specially designed water channel in which the starting flow was obtained using a high torque stepping motor controlled through computer software. A cine film of the dye-in-water patterns produced by the flow was made from which photographic sequences showing the flow development and measurements of the timewise primary vortex trajectory were obtained. Details of the flow revealed in selected photographic sequences are discussed, and the measured vortex center trajectories are compared with inviscid similarity theory predictions.

  12. Flow visualization using the laser light sheet method in vehicle aerodynamics and combustion chamber engineering

    NASA Astrophysics Data System (ADS)

    Hentschel, Werner

    Laser light sheet flow visualization is applied in the automobile industry with a view to the reduction of air resistance. Using high power lasers a plane is cut out of the 3-D flow field and the course of flow in the plane is analyzed. In vehicle aerodynamics the flow phenomena are mainly visualized with smoke in the tail region of automobiles and in the wake, in planes parallel as well as perpendicular to the flow direction. For the investigation of flow phenomena in the combustion chamber of Otto and Diesel engines, the laser light sheet method is used on a series motor with optical access, the so-called flow motor. Typical results and requirements for future automated evaluation methods are discussed.

  13. Visualization of three-dimensional incompressible flows by quasi-two-dimensional divergence-free projections in arbitrary flow regions

    NASA Astrophysics Data System (ADS)

    Gelfgat, Alexander Yu.

    2016-08-01

    A visualization of three-dimensional incompressible flows by divergence-free quasi-two-dimensional projections of the velocity field onto three coordinate planes is revisited. An alternative and more general way to compute the projections is proposed. The approach is based on the Chorin projection combined with a SIMPLE-like iteration. Compared to the previous methodology based on divergence-free Galerkin-Chebyshev bases, this technique, formulated in general curvilinear coordinates, is applicable to any flow region and allows for faster computations. To illustrate this visualization method, examples in Cartesian and spherical coordinates, as well as post-processing of experimental 3D-PTV data, are presented.

  14. MatrixFlow: Temporal Network Visual Analytics to Track Symptom Evolution during Disease Progression

    PubMed Central

    Perer, Adam; Sun, Jimeng

    2012-01-01

    Objective: To develop a visual analytic system to help medical professionals improve disease diagnosis by providing insights for understanding disease progression. Methods: We develop MatrixFlow, a visual analytic system that takes clinical event sequences of patients as input, constructs time-evolving networks and visualizes them as a temporal flow of matrices. MatrixFlow provides several interactive features for analysis: 1) one can sort the events based on the similarity in order to accentuate underlying cluster patterns among those events; 2) one can compare co-occurrence events over time and across cohorts through additional line graph visualization. Results: MatrixFlow is applied to visualize heart failure (HF) symptom events extracted from a large cohort of HF cases and controls (n=50,625), which allows medical experts to reach insights involving temporal patterns and clusters of interest, and compare cohorts in novel ways that may lead to improved disease diagnoses. Conclusions: MatrixFlow is an interactive visual analytic system that allows users to quickly discover patterns in clinical event sequences. By unearthing the patterns hidden within and displaying them to medical experts, users become empowered to make decisions influenced by historical patterns. PMID:23304345

  15. Visualization study on the static flow field around a straight-bladed vertical axis wind turbine

    NASA Astrophysics Data System (ADS)

    Li, Yan; Tagawa, Kotaro

    2010-03-01

    Visual experiments based on the smoke wire way were carried out on a small model of Straight-blade Vertical Axis Wind Turbine (SB-VAWT) to invest the relationship between the static flow field characteristics and the rotor azimuth angle. The test rotor had 3 blades with NACA0018 aerofoil. The rotor diameter and blade chord were 0.3m and 0.07m, respectively. Visual photos of the static flow path lines in and around the rotor were obtained at every 5 degrees of the azimuth angle. Further, numerical computations of the static flow filed were also carried out for comparison with the same situation as the visual tests and the static torques at different azimuth angles were calculated. According to the results of visual tests and computations, the dependence of the starting performance on the azimuth angle was discussed. The solidity is an important factor affecting the starting performance of the SB-VAWT.

  16. Visualization study on the static flow field around a straight-bladed vertical axis wind turbine

    NASA Astrophysics Data System (ADS)

    Li, Yan; Tagawa, Kotaro

    2009-12-01

    Visual experiments based on the smoke wire way were carried out on a small model of Straight-blade Vertical Axis Wind Turbine (SB-VAWT) to invest the relationship between the static flow field characteristics and the rotor azimuth angle. The test rotor had 3 blades with NACA0018 aerofoil. The rotor diameter and blade chord were 0.3m and 0.07m, respectively. Visual photos of the static flow path lines in and around the rotor were obtained at every 5 degrees of the azimuth angle. Further, numerical computations of the static flow filed were also carried out for comparison with the same situation as the visual tests and the static torques at different azimuth angles were calculated. According to the results of visual tests and computations, the dependence of the starting performance on the azimuth angle was discussed. The solidity is an important factor affecting the starting performance of the SB-VAWT.

  17. Flow visualization efforts and pilot measurements with a laser-Doppler anemometer in backscatter mode

    NASA Technical Reports Server (NTRS)

    Buetefisch, K. A.

    1982-01-01

    Activities involving the use flow visualization and laser anemometers are reviewed. In particular, turbulent pipe flow measurements and local velocity determination in a 3 X 3 sq meter wind tunnel are discussed. The calibration of laser anemometer systems using a rotating disk is also addressed.

  18. Summary of in-flight flow visualization obtained from the NASA high alpha research vehicle

    NASA Technical Reports Server (NTRS)

    Fisher, David F.; Delfrate, John H.; Zuniga, Fanny A.

    1991-01-01

    A summary of the surface and off-surface flow visualization results obtained in flight on the F-18 high alpha research vehicle (HARV) is presented, highlighting the extensive 3-D vortical flow on the aircraft at angles of attack up to 50 degs. The emitted fluid technique, as well as tufts and flow cones, were used to document the surface flow. A smoke generator system injected smoke into the vortex cores generated by the forebody and leading edge extensions (LEXs). Documentation was provided by onboard still and video, by air-to-air, and by postflight photography. The surface flow visualization techniques revealed laminar separation bubbles near the forebody apex, lines of separation on the forebody and LEX, and regions of attached and separated flow on the wings and fins. The off-surface flow visualization techniques showed the path of the vortex cores on the forebody and LEX as well as the LEX vortex core breakdown location. An interaction between the forebody and LEX vortices was noted. The flow over the surfaces of the vertical tail was categorized into regions of attached, unsteady, or separated flow using flow tufts.

  19. Visual analysis of the quantitative composition of metagenomic communities: the AmphoraVizu webserver.

    PubMed

    Kerepesi, Csaba; Szalkai, Balázs; Grolmusz, Vince

    2015-04-01

    Low-cost DNA sequencing methods have given rise to an enormous development of metagenomics in the past few years. One basic--and difficult--task is the phylogenetic annotation of the metagenomic samples studied. The difficulty comes from the fact that the typical environmental sample contains hundreds of unknown and still uncharacterized microorganisms. There are several possible methods to assign at least partial phylogenetic information to these uncharacterized data. Originally, the 16S ribosomal RNA was used as phylogenetic marker, then genome sequence alignments and similarity measures between the unknown genome and the reference genomes were applied (e.g., in the MEGAN software), and more recently, phylogeny-based methods applying suitable sets of marker genes were suggested (AMPHORA, AMPHORA2, and the webserver implementation AmphoraNet). Here, we present a visual analysis tool that is capable of demonstrating the quantitative relations gained from the output of the AMPHORA2 program or the easy-to-use AmphoraNet webserver. Our web-based tool, the AmphoraVizu webserver, makes the phylogenetic distribution of the metagenomic sample clearly visible by using the native output format of AMPHORA2 or AmphoraNet. The user may set the phylogenetic resolution (i.e., superkingdom, phylum, class, order, family, genus, and species) along with the chart type and will receive the distribution data detailed for all relevant marker genes in the sample. For publication quality results, the chart labels can be customized by the user. The visualization webserver is available at the address http://amphoravizu.pitgroup.org. The AmphoraNet webserver is available at http://amphoranet.pitgroup.org. The open-source version of the AmphoraVizu program is available for download at http://pitgroup.org/apps/amphoravizu/AmphoraVizu.pl. PMID:25296554

  20. Visual analysis of the quantitative composition of metagenomic communities: the AmphoraVizu webserver.

    PubMed

    Kerepesi, Csaba; Szalkai, Balázs; Grolmusz, Vince

    2015-04-01

    Low-cost DNA sequencing methods have given rise to an enormous development of metagenomics in the past few years. One basic--and difficult--task is the phylogenetic annotation of the metagenomic samples studied. The difficulty comes from the fact that the typical environmental sample contains hundreds of unknown and still uncharacterized microorganisms. There are several possible methods to assign at least partial phylogenetic information to these uncharacterized data. Originally, the 16S ribosomal RNA was used as phylogenetic marker, then genome sequence alignments and similarity measures between the unknown genome and the reference genomes were applied (e.g., in the MEGAN software), and more recently, phylogeny-based methods applying suitable sets of marker genes were suggested (AMPHORA, AMPHORA2, and the webserver implementation AmphoraNet). Here, we present a visual analysis tool that is capable of demonstrating the quantitative relations gained from the output of the AMPHORA2 program or the easy-to-use AmphoraNet webserver. Our web-based tool, the AmphoraVizu webserver, makes the phylogenetic distribution of the metagenomic sample clearly visible by using the native output format of AMPHORA2 or AmphoraNet. The user may set the phylogenetic resolution (i.e., superkingdom, phylum, class, order, family, genus, and species) along with the chart type and will receive the distribution data detailed for all relevant marker genes in the sample. For publication quality results, the chart labels can be customized by the user. The visualization webserver is available at the address http://amphoravizu.pitgroup.org. The AmphoraNet webserver is available at http://amphoranet.pitgroup.org. The open-source version of the AmphoraVizu program is available for download at http://pitgroup.org/apps/amphoravizu/AmphoraVizu.pl.

  1. Quantitative Tracking of Isotope Flows in Proteomes of Microbial Communities*

    PubMed Central

    Pan, Chongle; Fischer, Curt R.; Hyatt, Doug; Bowen, Benjamin P.; Hettich, Robert L.; Banfield, Jillian F.

    2011-01-01

    Stable isotope probing (SIP) has been used to track nutrient flows in microbial communities, but existing protein-based SIP methods capable of quantifying the degree of label incorporation into peptides and proteins have been demonstrated only by targeting usually less than 100 proteins per sample. Our method automatically (i) identifies the sequence of and (ii) quantifies the degree of heavy atom enrichment for thousands of proteins from microbial community proteome samples. These features make our method suitable for comparing isotopic differences between closely related protein sequences, and for detecting labeling patterns in low-abundance proteins or proteins derived from rare community members. The proteomic SIP method was validated using proteome samples of known stable isotope incorporation levels at 0.4%, ∼50%, and ∼98%. The method was then used to monitor incorporation of 15N into established and regrowing microbial biofilms. The results indicate organism-specific migration patterns from established communities into regrowing communities and provide insights into metabolism during biofilm formation. The proteomic SIP method can be extended to many systems to track fluxes of 13C or 15N in microbial communities. PMID:21285414

  2. Quantitative tracking of isotope flows in proteomes of microbial communities

    SciTech Connect

    Fisher, Curt; Hyatt, Philip Douglas; Hettich, Robert {Bob} L; Banfield, Jillian F.

    2011-01-01

    Stable isotope probing (SIP) has been used to track nutrient flows in microbial communities, but existing protein-based SIP methods capable of quantifying the degree of label incorporation into peptides and proteins have been demonstrated only by targeting usually less than 100 proteins per sample. Our method automatically (i) identifies the sequence of and (ii) quantifies the degree of heavy atom enrichment for thousands of proteins from microbial community proteome samples. These features make our method suitable for comparing isotopic differences between closely related protein sequences, and for detecting labeling patterns in low-abundance proteins or proteins derived from rare community members. The proteomic stable isotope probing (SIP) method was validated using proteome samples of known stable isotope incorporation levels at 0.4%, {approx}50%, and {approx}98%. The method was then used to monitor incorporation of 15N into established and regrowing microbial biofilms. The results indicate organism-specific migration patterns from established into regrowing communities and provides insight into metabolism during biofilm formation. The SIP-proteomics method can be extended to many systems to track fluxes of 13C or 15N in microbial communities.

  3. Quantitative tracking of isotope flows in proteomes of microbial communities.

    PubMed

    Pan, Chongle; Fischer, Curt R; Hyatt, Doug; Bowen, Benjamin P; Hettich, Robert L; Banfield, Jillian F

    2011-04-01

    Stable isotope probing (SIP) has been used to track nutrient flows in microbial communities, but existing protein-based SIP methods capable of quantifying the degree of label incorporation into peptides and proteins have been demonstrated only by targeting usually less than 100 proteins per sample. Our method automatically (i) identifies the sequence of and (ii) quantifies the degree of heavy atom enrichment for thousands of proteins from microbial community proteome samples. These features make our method suitable for comparing isotopic differences between closely related protein sequences, and for detecting labeling patterns in low-abundance proteins or proteins derived from rare community members. The proteomic SIP method was validated using proteome samples of known stable isotope incorporation levels at 0.4%, ∼50%, and ∼98%. The method was then used to monitor incorporation of (15)N into established and regrowing microbial biofilms. The results indicate organism-specific migration patterns from established communities into regrowing communities and provide insights into metabolism during biofilm formation. The proteomic SIP method can be extended to many systems to track fluxes of (13)C or (15)N in microbial communities.

  4. Flow visualization of time-varying structural characteristics of dean vortices in a curved channel

    NASA Astrophysics Data System (ADS)

    Bella, David Wayne

    1988-12-01

    The time varying development and structure of Dean vortices were studied using flow visualization. Observations were made over a range of Dean numbers from 40 to 200 using a transparent channel with mild curvature, 40:1 aspect ratio, and an inner to outer radius ratio of 0.979. Seven flow visualization techniques were tried but only one, a wood burning smoke generator, produced usable results. Different vortex characteristics were observed and documented in sequences of photographs spaced one quarter of a second apart at locations ranging from 85 to 135 degrees from the start of curvature. Evidence is presented that supports the twisting/rocking nature of the flow.

  5. Visualization of longitudinal vortex flow in an enhanced heat transfer tube

    SciTech Connect

    Li, Xiao-wei; Yan, Huan; Meng, Ji-an; Li, Zhi-xin

    2007-05-15

    Longitudinal vortex flow was visualized in an enlarged DDIR tube (discrete double inclined ribs on the inner surface). The experiments were conducted in a water tunnel using dye injection. Two kinds of ribs with different widths were investigated. The visualizations showed counter rotating longitudinal vortex pairs formed by the discrete double inclined ribs. The vortex intensity increased with increasing Reynolds numbers while the length over which the vortices were observed along the flow direction decreased with increasing Reynolds numbers for Re = 1000-2000. The vortex intensity and vortex flow length were also strongly affected by the rib dimensions. (author)

  6. Flow Visualization Study of a 1/48-Scale AFTI/F111 Model to Investigate Horizontal Tail Flow Disturbances

    NASA Technical Reports Server (NTRS)

    Bjarke, Lisa J.

    1991-01-01

    During flight testing of the AFTI/F111 aircraft, horizontal tail buffet was observed. Flutter analysis ruled out any aeroelastic instability, so a water-tunnel flow visualization study was conducted to investigate possible flow disturbances on the horizontal tail which might cause buffet. For this study, a 1/48-scale model was used. Four different wing cambers and one horizontal tail setting were tested between 0 and 20 deg angle of attack. These wing cambers corresponded to the following leading training edge deflections: 0/2, 10/10, 10/2, and 0/10. Flow visualization results in the form of still photographs are presented for each of the four wing cambers between 8 and 12 deg angle of attack. In general, the horizontal tail experiences flow disturbances which become more pronounced with angle of attack or wing trailing-edge deflection.

  7. Visualization of scavenging flow in the design of small two-stroke engines

    NASA Astrophysics Data System (ADS)

    Stuecke, Peter; Egbers, Christoph

    2006-06-01

    An experimental test rig is presented, which enables visual examination of the internal flow of piston ported two-stroke cylinders. Similarity laws are applied to design the layout of the set-up. The reasons to use a liquid to represent the scavenging fluid are explained. Experiments are carried out which visualize the scavenging flow inside the cylinder. Colours play an important role in the visualization of flows. Careful selection of the dyes and the particular arrangement of different colours produce features of the three-dimensional and unsteady flow under investigation. The potential for future investigations to become an integrated part of the design process of small two-stroke engines is demonstrated.

  8. Diode-laser-based near-resonantly enhanced flow visualization in shock tunnels.

    PubMed

    Hruschka, Robert; O'Byrne, Sean; Kleine, Harald

    2008-08-20

    Two new near-resonantly enhanced flow visualization techniques suitable for hypersonic low-density flows in shock or arc tunnels have been developed using seeded lithium (Li) metal as the refractivity-enhancing species. Two semiconductor lasers, single-longitudinal-mode and multimode, are compared with respect to their suitability as light sources for the technique. Transient wake-flow structures around a cylinder and a model of a planetary entry vehicle are visualized to demonstrate the capabilities of this comparatively inexpensive and simple visualization system. The images show flow features which are undetectable with conventional schlieren, shadowgraph, or interferometry techniques. Furthermore, the effect of density inhomogeneities along the line-of-sight outside the region of interest can be reduced by enhancing the refractivity only in selected parts of the flowfield.

  9. Noninvasive visualization and measurement of middle cardiac vein flow by transthoracic Doppler echocardiography.

    PubMed

    Harada, Kenji; Tamura, Masamichi; Toyono, Manatoma

    2006-01-01

    Transthoracic Doppler echocardiography offers a noninvasive approach for imaging posterior descending coronary artery (PD) running in the posterior longitudinal sulcus along the middle cardiac vein (MCV). To evaluate whether the MCV flow velocity reserve can reflect the PD flow reserve, 22 children with various heart diseases were examined using transthoracic Doppler echocardiography. Introduction of a modified transthoracic two chamber view with the transducer rotated counterclockwise and angulated posteriorly allows visualization of the MCV and PD. Peak systolic flow velocity and average peak systolic flow velocity in the MCV and peak diastolic flow velocity and average peak diastolic flow velocity in the PD were measured at rest and hyperemic conditions (intravenous administration of adenosine of 0.16 mg/kg/min). Coronary flow reserve was defined as the ratio of peak hyperemic to basal average peak flow velocity. ATP infusion induced significant increases in the peak systolic flow velocity and average peak systolic flow velocity in the MCV. The mean MCV flow velocity reserve in the patients was 1.94 +/- 0.44. Significant increases in the peak diastolic flow velocity and the average peak diastolic flow velocity in the PD were also observed during ATP infusion, and the mean PD flow velocity reserve (2.19 +/- 0.62) was significantly higher than the GCV flow velocity reserve (p < 0.0001). There was a good correlation between the MCV flow velocity reserve and PD flow velocity reserve (r = 0.86, p < 0.0001). This study demonstrated that it was possible to measure the MCV flow velocity and MCV flow velocity reserve in pediatric patients by transthoracic Doppler echocardiography. The MCV flow reserve correlated highly with the PD flow reserve. However, the degree of the MCV flow during hyperemia was less than that of the PD flow. This underestimation should be considered when the reactive hyperemic response is evaluated from the MCV flow velocity. PMID:17031721

  10. Global Skin-Friction Measurements Using Particle Image Surface FLow Visualization and a Luminescent Oil-Film

    NASA Technical Reports Server (NTRS)

    Husen, Nicholas; Roozeboom, Nettie; Liu, Tianshu; Sullivan, John P.

    2015-01-01

    A quantitative global skin-friction measurement technique is proposed. An oil-film is doped with a luminescent molecule and thereby made to fluoresce in order to resolve oil-film thickness, and Particle Image Surface Flow Visualization is used to resolve the velocity field of the surface of the oil-film. Skin-friction is then calculated at location x as (x )xh, where x is the displacement of the surface of the oil-film and is the dynamic viscosity of the oil. The data collection procedure and data analysis procedures are explained, and preliminary experimental skin-friction results for flow over the wing of the CRM are presented.

  11. 1/48-scale model of an F-18 aircraft in Flow Visualization Facility (FVF)

    NASA Technical Reports Server (NTRS)

    1980-01-01

    This short movie clip shows a plastic 1/48-scale model of an F-18 aircraft inside the 'Water Tunnel' more formally known as the NASA Dryden Flow Visualization Facility. Water is pumped through the tunnel in the direction of normal airflow over the aircraft; then, colored dyes are pumped through tubes with needle valves. The dyes flow back along the airframe and over the airfoils highlighting their aerodynamic characteristics. The aircraft can also be moved through its pitch axis to observe airflow disruptions while simulating actual flight at high angles of attack. The Water Tunnel at NASA's Dryden Flight Research Center, Edwards, CA, became operational in 1983 when Dryden was a Flight Research Facility under the management of the Ames Research Center in Mountain View, CA. As a medium for visualizing fluid flow, water has played a significant role. Its use dates back to Leonardo da Vinci (1452-1519), the Renaissance Italian engineer, architect, painter, and sculptor. In more recent times, water tunnels have assisted the study of complex flows and flow-field interactions on aircraft shapes that generate strong vortex flows. Flow visualization in water tunnels assists in determining the strength of vortices, their location, and possible methods of controlling them. The design of the Dryden Water Tunnel imitated that of the Northrop Corporation's tunnel in Hawthorne, CA. Called the Flow Visualization Facility, the Dryden tunnel was built to assist researchers in understanding the aerodynamics of aircraft configured in such a way that they create strong vortex flows, particularly at high angles of attack. The tunnel provides results that compare well with data from aircraft in actual flight in another fluid-air. Other uses of the tunnel have included study of how such flight hardware as antennas, probes, pylons, parachutes, and experimental fixtures affect airflow. The facility has also been helpful in finding the best locations for emitting smoke from flight vehicles

  12. 1/48-scale model of an F-18 aircraft in Flow Visualization Facility (FVF)

    NASA Technical Reports Server (NTRS)

    1985-01-01

    This image shows a plastic 1/48-scale model of an F-18 aircraft inside the 'Water Tunnel' more formally known as the NASA Dryden Flow Visualization Facility. Water is pumped through the tunnel in the direction of normal airflow over the aircraft; then, colored dyes are pumped through tubes with needle valves. The dyes flow back along the airframe and over the airfoils highlighting their aerodynamic characteristics. The aircraft can also be moved through its pitch axis to observe airflow disruptions while simulating actual flight at high angles of attack. The Water Tunnel at NASA's Dryden Flight Research Center, Edwards, CA, became operational in 1983 when Dryden was a Flight Research Facility under the management of the Ames Research Center in Mountain View, CA. As a medium for visualizing fluid flow, water has played a significant role. Its use dates back to Leonardo da Vinci (1452-1519), the Renaissance Italian engineer, architect, painter, and sculptor. In more recent times, water tunnels have assisted the study of complex flows and flow-field interactions on aircraft shapes that generate strong vortex flows. Flow visualization in water tunnels assists in determining the strength of vortices, their location, and possible methods of controlling them. The design of the Dryden Water Tunnel imitated that of the Northrop Corporation's tunnel in Hawthorne, CA. Called the Flow Visualization Facility, the Dryden tunnel was built to assist researchers in understanding the aerodynamics of aircraft configured in such a way that they create strong vortex flows, particularly at high angles of attack. The tunnel provides results that compare well with data from aircraft in actual flight in another fluid-air. Other uses of the tunnel have included study of how such flight hardware as antennas, probes, pylons, parachutes, and experimental fixtures affect airflow. The facility has also been helpful in finding the best locations for emitting smoke from flight vehicles for flow

  13. Paper electrode integrated lateral flow immunosensor for quantitative analysis of oxidative stress induced DNA damage

    PubMed Central

    Zhu, Xuena; Shah, Pratikkumar; Stoff, Susan; Liu, Hongyun; Li, Chen-zhong

    2014-01-01

    A novel device combining electrochemical and colorimetric detection is developed for the rapid measurement of 8-hydroxy-2′-deoxyguanosine (8-OHdG), a DNA oxidative damage biomarker. The device takes advantage of the speed and low cost of the conventional strip test as well as the high reliability and accuracy of electrochemical assay. Competitive immunoreactions were performed on the lateral flow strip, and the captured 8-OHdG on the control line was determined by chronoamperometric measurement with carbon nanotubes paper as the working electrode. At the same time, the color intensity of the test line was measured by a scanner and analyzed by the ImageJ software. The device was able to detect 8-OHdG concentrations in PBS as low as 2.07 ng mL−1 by the colorimetric method and 3.11 ng mL−1 by the electrochemical method. Furthermore, the device was successfully utilized to detect 8-OHdG in urine with a detection limit of 5.76 ng mL−1 (colorimetric method) and 8.85 ng mL−1 (electrochemical method), respectively. In conclusion, the integrated device with dual detections can provide a rapid, visual, quantitative and feasible detection method for 8-OHdG. The integration of these two methods holds two major advantages over tests based on single method. Firstly, it can provide double confidence on the same assay. Secondly, by involving two methods that differ in principle, the integration could potentially avoid false results coming from one method. In addition, these methods do not require expensive equipment or trained personnel, deeming it suitable for use as a simple, economical, portable field kit for on-site monitoring of 8-OHdG in a variety of clinical settings. PMID:24733353

  14. In-Flight Flow Visualization Results of the F-106B with a Vortex Flap

    NASA Technical Reports Server (NTRS)

    Brandon, Jay M.; Hallissy, James B.; Brown, Philip W.; Lamar, John E.

    2003-01-01

    Surface and off-surface flow visualization techniques were used to visualize the three-dimensional vortex flows on the F-106 aircraft with vortex flaps installed. Results at angles of attack between 9 degrees to 18 degrees and Mach numbers from 0.3 to 0.9 are presented. A smoke flow vapor screen technique was used to document leading-edge vortex paths and sizes, while an oil flow technique was employed to provide detailed information on reattachment and separation line locations and other flow details. Results were obtained for two vortex flap deflection angles, 30 degrees and 40 degrees. Flow visualization revealed the existence of a multiple vortex system that had not previously been seen in subscale tests or predicted for this configuration. The vortex flap generated a leading-edge vortex system that reattached near the flap hinge over a wide angle of attack range. In addition to the primary vortex, flow visualization revealed the presence of several distinct vortices which traced a path from the vortex flap and then over the wing.

  15. In-Flight Flow Visualization Results of The F-106B With a Vortex Flap

    NASA Technical Reports Server (NTRS)

    Brandon, Jay M.; Hallissy, James B.; Brown, Philip W.; Lamar, John E.

    2001-01-01

    Surface and off-surface flow visualization techniques were used to visualize the three-dimensional vortex flows on the F-106 aircraft with vortex flaps installed. Results at angles of attack between 9 deg to 18 deg and Mach numbers from 0.3 to 0.9 are presented. A smoke flow vapor screen technique was used to document leading-edge vortex paths and sizes, while an oil flow technique was employed to provide detailed information on reattachment and separation line locations and other flow details. Results were obtained for two vortex flap deflection angles, 30 deg and 40 deg. Flow visualization revealed the existence of a multiple vortex system that had not previously been seen in subscale tests or predicted for this configuration. The vortex flap generated a leading-edge vortex system that reattached near the flap hinge over a wide angle of attack range. In addition to the primary vortex, flow visualization revealed the presence of several distinct vortices which traced a path from the vortex flap and then over the wing.

  16. Flow Visualization of Liquid Hydrogen Line Chilldown Tests

    NASA Technical Reports Server (NTRS)

    Rame, Enrique; Hartwig, Jason W.; McQuillen John B.

    2014-01-01

    We present experimental measurements of wall and fluid temperature during chill-down tests of a warm cryogenic line with liquid hydrogen. Synchronized video and fluid temperature measurements are used to interpret stream temperature profiles versus time. When cold liquid hydrogen starts to flow into the warm line, a sequence of flow regimes, spanning from all-vapor at the outset to bubbly with continuum liquid at the end can be observed at a location far downstream of the cold inlet. In this paper we propose interpretations to the observed flow regimes and fluid temperature histories for two chilldown methods, viz. trickle (i.e. continuous) flow and pulse flow. Calculations of heat flux from the wall to the fluid versus wall temperature indicate the presence of the transition/nucleate boiling regimes only. The present tests, run at typical Reynolds numbers of approx O(10 (exp 5)), are in sharp contrast to similar tests conducted at lower Reynolds numbers where a well-defined film boiling region is observed.

  17. NMR visualization of displacement correlations for flow in porous media.

    PubMed

    Khrapitchev, A A; Stapf, S; Callaghan, P T

    2002-11-01

    The temporal correlations of velocities for both water and a water-glycerol mixture flowing through a random packings of monodisperse spherical particles have been investigated using two-dimensional nuclear magnetic resonance methods. By combining various flow rates, fluid viscosities, and bead sizes, a wide range of flow parameters has been covered, the dimensionless Peclet number ranging from 100 to 100 000. The velocity exchange spectroscopy (VEXSY) technique has been employed to measure the correlation between velocities during two intervals separated from each other by a mixing time tau(m). This time is made both large and small compared with the time constant tau(c), required for a fluid element possessing the average flow velocity to cover a distance equal to the characteristic size in the system, the bead diameter. The two-dimensional conditional probability of displacement resulting from the VEXSY method reveals the existence of different "subensembles" of molecules, including a slow moving pool whose displacement is dominated by Brownian motion, an intermediate ensemble whose velocities change little over the mixing time, and a fast flowing ensemble which loses correlation due to mechanical dispersion. We find that that the approach to asymptotic dispersion, as tau(c)/tau(m) increases, depends strongly on the Peclet number, the deviation of the velocity autocorrelation function from a monoexponential Ornstein-Uhlenbeck process becoming more pronounced with increasing Peclet number. PMID:12513475

  18. Visually observed mold and moldy odor versus quantitatively measured microbial exposure in homes.

    PubMed

    Reponen, Tiina; Singh, Umesh; Schaffer, Chris; Vesper, Stephen; Johansson, Elisabet; Adhikari, Atin; Grinshpun, Sergey A; Indugula, Reshmi; Ryan, Patrick; Levin, Linda; Lemasters, Grace

    2010-10-15

    The main study objective was to compare different methods for assessing mold exposure in conjunction with an epidemiologic study on the development of children's asthma. Homes of 184 children were assessed for mold by visual observations and dust sampling at child's age 1 (Year 1). Similar assessment supplemented with air sampling was conducted in Year 7. Samples were analyzed for endotoxin, (1-3)-β-D-glucan, and fungal spores. The Mold Specific Quantitative Polymerase Chain Reaction assay was used to analyze 36 mold species in dust samples, and the Environmental Relative Moldiness Index (ERMI) was calculated. Homes were categorized based on three criteria: 1) visible mold damage, 2) moldy odor, and 3) ERMI. Even for homes where families had not moved, Year 7 endotoxin and (1-3)-β-d-glucan exposures were significantly higher than those in Year 1 (p<0.001), whereas no difference was seen for ERMI (p=0.78). Microbial concentrations were not consistently associated with visible mold damage categories, but were consistently higher in homes with moldy odor and in homes that had high ERMI. Low correlations between results in air and dust samples indicate different types or durations of potential microbial exposures from dust vs. air. Future analysis will indicate which, if any, of the assessment methods is associated with the development of asthma.

  19. Visually observed mold and moldy odor versus quantitatively measured microbial exposure in homes

    PubMed Central

    Reponen, Tiina; Singh, Umesh; Schaffer, Chris; Vesper, Stephen; Johansson, Elisabet; Adhikari, Atin; Grinshpun, Sergey A.; Indugula, Reshmi; Ryan, Patrick; Levin, Linda; LeMasters, Grace

    2010-01-01

    The main study objective was to compare different methods for assessing mold exposure in conjunction with an epidemiologic study on the development of children’s asthma. Homes of 184 children were assessed for mold by visual observations and dust sampling at child’s age 1 (Year 1). Similar assessment supplemented with air sampling was conducted in Year 7. Samples were analyzed for endotoxin, (1–3)-β-D-glucan, and fungal spores. The Mold Specific Quantitative Polymerase Chain Reaction assay was used to analyze 36 mold species in dust samples, and the Environmental Relative Moldiness Index (ERMI) was calculated. Homes were categorized based on three criteria: 1) visible mold damage, 2) moldy odor, and 3) ERMI. Even for homes where families had not moved, Year 7 endotoxin and (1–3)-β-D-glucan exposures were significantly higher than those in Year 1 (p<0.001), whereas no difference was seen for ERMI (p=0.78). Microbial concentrations were not consistently associated with visible mold damage categories, but were consistently higher in homes with moldy odor and in homes that had high ERMI. Low correlations between results in air and dust samples indicate different types or durations of potential microbial exposures from dust vs. air. Future analysis will indicate which, if any, of the assessment methods is associated with the development of asthma. PMID:20810150

  20. Extraction of skin-friction fields from surface flow visualizations as an inverse problem

    NASA Astrophysics Data System (ADS)

    Liu, Tianshu

    2013-12-01

    Extraction of high-resolution skin-friction fields from surface flow visualization images as an inverse problem is discussed from a unified perspective. The surface flow visualizations used in this study are luminescent oil-film visualization and heat-transfer and mass-transfer visualizations with temperature- and pressure-sensitive paints (TSPs and PSPs). The theoretical foundations of these global methods are the thin-oil-film equation and the limiting forms of the energy- and mass-transport equations at a wall, which are projected onto the image plane to provide the relationships between a skin-friction field and the relevant quantities measured by using an imaging system. Since these equations can be re-cast in the same mathematical form as the optical flow equation, they can be solved by using the variational method in the image plane to extract relative or normalized skin-friction fields from images. Furthermore, in terms of instrumentation, essentially the same imaging system for measurements of luminescence can be used in these surface flow visualizations. Examples are given to demonstrate the applications of these methods in global skin-friction diagnostics of complex flows.

  1. Interplay of Natural Organic Matter with Flow Rate and Particle Size on Colloid Transport: Experimentation, Visualization, and Modeling.

    PubMed

    Yang, Xinyao; Zhang, Yimeng; Chen, Fangmin; Yang, Yuesuo

    2015-11-17

    The investigation on factors that affect the impact of natural organic matter (NOM) on colloid transport in complex hydraulic flow systems remains incomplete. Using our previously established approach, the interplay of flow rate and particle size on the NOM effect was quantified, using flow rates of 1 and 2 mL/min and particle sizes of 50 and 200 nm to represent small nanoparticles (1-100 nm) and large non-nano-microspheres (100-1000 nm) in the low-flow groundwater environment. Latex particles, Suwannee River humic acid (SRHA), and iron oxide-coated sand were used as model particles, NOM, and the aquifer medium, respectively. The quantitative results show NOM blocked more sites for large particles at a high flow rate: 1 μg of SRHA blocked 5.95 × 10(9) microsphere deposition sites at 2 mL/min but only 7.38 × 10(8) nanoparticle deposition sites at 1 mL/min. The particle size effect dominated over the flow rate, and the overall effect of the two is antagonistic. Granule-scale visualization of the particle packing on the NOM-presented sand surface corroborates the quantification results, revealing a more dispersed status of large particles at a high flow rate. We interpret this phenomenon as a polydispersivity effect resulting from the differential size of the particles and NOM: high flow and a high particle size enlarge the ratio of particle-blocked to NOM-blocked areas and thus the NOM blockage. To our knowledge, this is the first model-assisted quantification on the interplay of NOM, flow rate, and particle size on colloid transport. These findings are significant for nanorisk assessment and nanoremediation practices.

  2. Interplay of Natural Organic Matter with Flow Rate and Particle Size on Colloid Transport: Experimentation, Visualization, and Modeling.

    PubMed

    Yang, Xinyao; Zhang, Yimeng; Chen, Fangmin; Yang, Yuesuo

    2015-11-17

    The investigation on factors that affect the impact of natural organic matter (NOM) on colloid transport in complex hydraulic flow systems remains incomplete. Using our previously established approach, the interplay of flow rate and particle size on the NOM effect was quantified, using flow rates of 1 and 2 mL/min and particle sizes of 50 and 200 nm to represent small nanoparticles (1-100 nm) and large non-nano-microspheres (100-1000 nm) in the low-flow groundwater environment. Latex particles, Suwannee River humic acid (SRHA), and iron oxide-coated sand were used as model particles, NOM, and the aquifer medium, respectively. The quantitative results show NOM blocked more sites for large particles at a high flow rate: 1 μg of SRHA blocked 5.95 × 10(9) microsphere deposition sites at 2 mL/min but only 7.38 × 10(8) nanoparticle deposition sites at 1 mL/min. The particle size effect dominated over the flow rate, and the overall effect of the two is antagonistic. Granule-scale visualization of the particle packing on the NOM-presented sand surface corroborates the quantification results, revealing a more dispersed status of large particles at a high flow rate. We interpret this phenomenon as a polydispersivity effect resulting from the differential size of the particles and NOM: high flow and a high particle size enlarge the ratio of particle-blocked to NOM-blocked areas and thus the NOM blockage. To our knowledge, this is the first model-assisted quantification on the interplay of NOM, flow rate, and particle size on colloid transport. These findings are significant for nanorisk assessment and nanoremediation practices. PMID:26469806

  3. Flow visualization and relative permeability measurements in rough-walled fractures

    SciTech Connect

    Persoff, P.; Pruess, K.

    1993-01-01

    Two-phase (gas-liquid) flow experiments were done in a natural rock fracture and transparent replicas of natural fractures. Liquid was injected at constant volume flow rate, and gas was injected at either constant mass flow rate or constant pressure. When gas was injected at constant mass flow rate, the gas inlet pressure, and inlet and outlet capillary pressures, generally did not reach steady state but cycled irregularly. Flow visualization showed that this cycling was due to repeated blocking and unblocking of gas flow paths by liquid. Relative permeabilities calculated from flow rate and pressure data show that the sum of the relative permeabilities of the two phases is much less than 1, indicating that each phase interferes strongly with the flow of the other. Comparison of the relative permeability curves with typical curves for porous media (Corey curves) show that the phase interference is stronger in fractures than in typical porous media.

  4. A Quantitative Comparison of Leading-edge Vortices in Incompressible and Supersonic Flows

    NASA Technical Reports Server (NTRS)

    Wang, F. Y.; Milanovic, I. M.; Zaman, K. B. M. Q.

    2002-01-01

    When requiring quantitative data on delta-wing vortices for design purposes, low-speed results have often been extrapolated to configurations intended for supersonic operation. This practice stems from a lack of database owing to difficulties that plague measurement techniques in high-speed flows. In the present paper an attempt is made to examine this practice by comparing quantitative data on the nearwake properties of such vortices in incompressible and supersonic flows. The incompressible flow data are obtained in experiments conducted in a low-speed wind tunnel. Detailed flow-field properties, including vorticity and turbulence characteristics, obtained by hot-wire and pressure probe surveys are documented. These data are compared, wherever possible, with available data from a past work for a Mach 2.49 flow for the same wing geometry and angles-of-attack. The results indicate that quantitative similarities exist in the distributions of total pressure and swirl velocity. However, the streamwise velocity of the core exhibits different trends. The axial flow characteristics of the vortices in the two regimes are examined, and a candidate theory is discussed.

  5. Electron-beam flow visualization - Applications in the definition of configuration aerothermal characteristics.

    NASA Technical Reports Server (NTRS)

    Woods, W. C.; Arrington, J. P.

    1972-01-01

    Comparisons between flow visualization systems using electron-beam fluorescence, schlieren, and shadowgraph techniques illustrate the advantages associated with the electron beam. Specific applications of this method as an aid in defining the origin of erosion on a heat-transfer model are cited. Results of combined electron-beam oil-flow studies on configurations illustrate that the simultaneous definition of the external flow field and its surface flow can be obtained. Comparisons between the electron-beam oil-flow visualization method and phase-change coating heat-transfer tests on a shuttle ascent configuration indicate the complementary nature of these two testing techniques. Potential methods for improving the electron-beam technique are included.

  6. Direct visualization of hemolymph flow in the heart of a grasshopper (Schistocerca americana)

    PubMed Central

    Lee, Wah-Keat; Socha, John J

    2009-01-01

    Background Hemolymph flow patterns in opaque insects have never been directly visualized due to the lack of an appropriate imaging technique. The required spatial and temporal resolutions, together with the lack of contrast between the hemolymph and the surrounding soft tissue, are major challenges. Previously, indirect techniques have been used to infer insect heart motion and hemolymph flow, but such methods fail to reveal fine-scale kinematics of heartbeat and details of intra-heart flow patterns. Results With the use of microbubbles as high contrast tracer particles, we directly visualized hemolymph flow in a grasshopper (Schistocerca americana) using synchrotron x-ray phase-contrast imaging. In-vivo intra-heart flow patterns and the relationship between respiratory (tracheae and air sacs) and circulatory (heart) systems were directly observed for the first time. Conclusion Synchrotron x-ray phase contrast imaging is the only generally applicable technique that has the necessary spatial, temporal resolutions and sensitivity to directly visualize heart dynamics and flow patterns inside opaque animals. This technique has the potential to illuminate many long-standing questions regarding small animal circulation, encompassing topics such as retrograde heart flow in some insects and the development of flow in embryonic vertebrates. PMID:19272159

  7. Fundamental investigation of duct/ESP phenomena: Flow visualization

    NASA Astrophysics Data System (ADS)

    Brown, C. T.; Sowa, W. A.; Samuelsen, G. S.

    1990-11-01

    The objective is to characterize the performance and behavior of twin-fluid atomizers used for in-duct sulfur capture. Such atomizers characteristically produce dense sprays featuring very narrow dispersion angles and high droplet velocities. To meet the objective, several tasks were identified (1) demonstrate the usefulness of phase Doppler interferometry to characterize humidification atomizers, (2) screen several commercially available atomizers to guide in the selection of nozzles used of field testing, and (3) develop a data base useful for computational code development and validation. The approach taken is to characterize the liquid phase produced by practical, full scale, twin-fluid humidification atomizers. Eight such twin-fluid atomizers are considered. Several of these atomizers were used in field tests. Only water sprays are considered. Atomizer responses to changes in air pressure (air flow rate) and water pressure (water flow rate) are examined. Measurements of droplet size and corresponding mean axial velocity are obtained.

  8. Flow Visualization Techniques in Wind Tunnel Tests of a Full-Scale F/A-18 Aircraft

    NASA Technical Reports Server (NTRS)

    Lanser, Wendy R.; Botha, Gavin J.; James, Kevin D.; Bennett, Mark; Crowder, James P.; Cooper, Don; Olson, Lawrence (Technical Monitor)

    1994-01-01

    The proposed paper presents flow visualization performed during experiments conducted on a full-scale F/A-18 aircraft in the 80- by 120-Foot Wind-Tunnel at NASA Ames Research Center. The purpose of the flow-visualization experiments was to document the forebody and leading edge extension (LEX) vortex interaction along with the wing flow patterns at high angles of attack and low speed high Reynolds number conditions. This investigation used surface pressures in addition to both surface and off-surface flow visualization techniques to examine the flow field on the forebody, canopy, LEXS, and wings. The various techniques used to visualize the flow field were fluorescent tufts, flow cones treated with reflective material, smoke in combination with a laser light sheet, and a video imaging system for three-dimension vortex tracking. The flow visualization experiments were conducted over an angle of attack range from 20 deg to 45 deg and over a sideslip range from -10 deg to 10 deg. The various visualization techniques as well as the pressure distributions were used to understand the flow field structure. The results show regions of attached and separated flow on the forebody, canopy, and wings as well as the vortical flow over the leading-edge extensions. This paper will also present flow visualization comparisons with the F-18 HARV flight vehicle and small-scale oil flows on the F-18.

  9. Flow Visualization Study of a Pulsating Respiratory Assist Catheter

    PubMed Central

    Budilarto, Stephanus G.; Frankowski, Brian J.; Hattler, Brack G.; Federspiel, William J.

    2007-01-01

    Our group is currently developing an intravenous respiratory assist device that uses a centrally located pulsatile balloon within a hollow fiber bundle to enhance gas exchange rate via active mixing mechanism. We tested the hypothesis that the nonsymmetric inflation and deflation of the balloon lead to both nonuniform balloon‐generated secondary flow and nonuniform gas exchange rate in the fiber bundle. The respiratory catheter was placed in a 1‐in. internal diameter rigid test section of an in vitro flow loop (3 L/min deionized water). Particle image velocimetry (PIV), which was used to map the velocity vector field in the lateral cross‐section, showed that the balloon pulsation generated a nonuniform fluid flow surrounding the respiratory assist catheter. PIV was also used to characterize the fiber bundle movement, which was induced by the balloon pulsation. Gas permeability coefficient of the device was evaluated by using both the fluid velocity and the relative velocity between the fluid and the fiber bundle. The highest difference in the gas permeability coefficient predicted by using the relative velocity was about 17% to 23% (angular direction), which was more uniform than the 49% to 59% variation predicted by using the fluid velocity. The movement of the fiber bundle was responsible for reducing the variation in the fluid velocity passing through the bundle and for minimizing the nonuniformity of the gas permeability coefficient of the respiratory assist catheter. PMID:16340349

  10. Quantitative values of blood flow through the human forearm, hand, and finger as functions of temperature

    NASA Technical Reports Server (NTRS)

    Montgomery, L. D.

    1974-01-01

    A literature search was made to obtain values of human forearm, hand and finger blood flow as functions of environmental temperature. The sources used include both government and laboratory reports and the research presented in the open literature. An attempt was made to review many of the more quantitative noninvasive determinations and to collate the results in such a way as to yield blood flow values for each body segment as continuous functions of temperature. A brief review of the various ways used to measure blood flow is included along with an abstract of each work from which data was taken.

  11. A package for 3-D unstructured grid generation, finite-element flow solution and flow field visualization

    NASA Technical Reports Server (NTRS)

    Parikh, Paresh; Pirzadeh, Shahyar; Loehner, Rainald

    1990-01-01

    A set of computer programs for 3-D unstructured grid generation, fluid flow calculations, and flow field visualization was developed. The grid generation program, called VGRID3D, generates grids over complex configurations using the advancing front method. In this method, the point and element generation is accomplished simultaneously, VPLOT3D is an interactive, menudriven pre- and post-processor graphics program for interpolation and display of unstructured grid data. The flow solver, VFLOW3D, is an Euler equation solver based on an explicit, two-step, Taylor-Galerkin algorithm which uses the Flux Corrected Transport (FCT) concept for a wriggle-free solution. Using these programs, increasingly complex 3-D configurations of interest to aerospace community were gridded including a complete Space Transportation System comprised of the space-shuttle orbitor, the solid-rocket boosters, and the external tank. Flow solutions were obtained on various configurations in subsonic, transonic, and supersonic flow regimes.

  12. Bioluminescence flow visualization in the ocean: an initial strategy based on laboratory experiments

    NASA Astrophysics Data System (ADS)

    Rohr, Jim; Hyman, Mark; Fallon, Stewart; Latz, Michael I.

    2002-11-01

    Observations of flow-stimulated bioluminescence have been recorded for centuries throughout the world's oceans. The present study explores, within a laboratory context, the use of naturally occurring bioluminescence as a strategy towards visualizing oceanic flow fields. The response of luminescent plankton to quantifiable levels of flow agitation was investigated in fully developed pipe flow. With two different pipe flow apparatus and freshly collected mixed plankton samples obtained over a year at two separate locations, several repeatable response patterns were identified. Threshold levels for bioluminescence stimulation occurred in laminar flow with wall shear stress levels generally between 1 and 2 dyn cm -2 (0.1-0.2 N m -2), equivalent to energy dissipation per unit mass values of 10 2-10 3 cm 2 s -3 (10 -2-10 -1 m 2 s -3). In an attempt to account for different concentrations and assemblages of mixed plankton, mean bioluminescence levels were normalized by an index of the corresponding flow-stimulated bioluminescence potential. This procedure generally accounted for variability between turbulent flow experiments, but was not effective for laminar flow. In turbulent flow, mean bioluminescence levels increased approximately linearly with wall shear stress. The magnitude of the flash response of individual cells, however, remained nearly constant throughout high laminar and turbulent flow, even as the energetic length scales of the turbulence became less than the size of the organisms of interest. Threshold flow stimuli levels determined in the laboratory were compared with oceanic measurements taken from the literature and with numerical simulations of ship wakes, one of the few highly turbulent flows to be well studied. Several oceanic flow fields are proposed as candidates for bioluminescence flow visualization.

  13. Temperature and Pressure Measurements and Visualization of He II Cavitation Flow through Venturi Channel

    SciTech Connect

    Ishii, T.; Murakami, M.; Harada, K.

    2004-06-23

    He II cavitation flow through a Venturi channel was experimentally investigated through temperature and pressure measurements and optical visualization. So far some distinctive features of cavitation between He II and He I flows were clarified. Then, detailed measurements were added for further investigation, such as the measurements of the temperature drop distribution throughout the flow channel and the void fraction. Further considerations were given on the cavitation inception with emphasis on the superheating of liquid helium, and the effect of the flow separation on cavitation.

  14. Flow visualization study of post critical heat flux region for inverted bubbly, slug and annular flow regimes

    SciTech Connect

    Denten, J.G.; Ishii, M.

    1988-11-01

    A visual study of film boiling using still photographic and high- speed motion picture methods was carried out in order to analyze the post-CHF hydrodynamics for steady-state inlet pre-CHF two-phase flow regimes. Pre-CHF two-phase flow regimes were established by introducing Freon 113 liquid and nitrogen gas into a jet core injection nozzle. An idealized, post-CHF two-phase core initial flow geometry (cylindrical multiphase jet core surrounded by a coaxial annulus of gas) was established at the nozzle exit by introducing nitrogen gas into the annular gap between the jet nozzle two-phase effluent and the heated test section inlet. For the present study three basic post-CHF flow regimes have been observed: the rough wavy regime (inverted annular flow preliminary break down), the agitated regime (transition between inverted annular and dispersed droplet flow), and the dispersed ligament/droplet regime. For pre-CHF bubbly flow in the jet nozzle, the post-CHF flow (beginning from jet nozzle exit/heated test section inlet) consists of the rough wavy regime, followed by the agitated and then the dispersed ligament/droplet regime. In the same way, for pre-CHF slug flow in the jet core, the post-CHF flow is comprised of the agitated regime at the nozzle exit, followed by the dispersed regime. Pre-CHF annular jet core flow results in a small, depleted post-CHF agitated flow regime at the nozzle exit, immediately followed by the dispersed ligament/droplet regime. Observed post dryout hydrodynamic behavior is reported, with particular attention given to the transition flow pattern between inverted annular and dispersed droplet flow. 43 refs., 20 figs., 5 tabs.

  15. Visualized flow patterns of double concentric jets at low annulus velocities

    NASA Astrophysics Data System (ADS)

    Huang, Rong F.; Lin, Chih L.

    1994-09-01

    The flow structures in the near wake region of the unducted double concentric jets at low Reynolds numbers are studied by smoke-wire flow visualization technique. Four typical characteristic flow regimes -- weak flow, pre-penetration, transition, and penetration -- are identified for different jet velocities in the near disk region. Flow patterns and behvaior in each characteristic flow regime are investigated. The contours of the separation surfaces and the lengths of the recirculation zone in various flow regimes are correlated with nondimensional parameters. The recirculation length reaches a maximum in the transition region. The toroidal recirculation region exhibits both expelling and shear-layer vortex shedding. The shedding processes are presented, and the frequencies are correlated with Strouhal number and central-to-annular jet velocity ratio.

  16. Flows in Porous Media: Visualization by Magnetic Resonance Imaging.

    NASA Astrophysics Data System (ADS)

    Shattuck, Mark David

    1995-01-01

    We have developed a Magnetic Resonance Imaging, MRI, technique which non-invasively measures local interstitial fluid velocity distributions in fully-saturated porous media. This was achieved by extending the standard three -dimensional MRI sequence to include local velocity and temperature information and adapted the technique to use the fast spin echo technique. We then applied this novel technique to two important problems. First, we studied pressure-driven flow through a fully-saturated, cylindrical packed bed. In this flow, we observed for the first time flow channeling inside a porous medium, as previously predicted. The MRI technique can also measure the local relative density. Which provides a non-invasive way of determining the spacial distribution of porosity in a porous medium. We used this information to verify previous findings concerning long -range spacial order and spacial oscillations in the porosity of packed beds of spheres. We found that the distribution of velocities in the flowing system is exponential. To our knowledge, this surprising fact has never before been documented. In the second application, we studied Porous Media Convection, PMC, from onset to eight times the critical Rayleigh number, Ra_{c}. We analyzed both ordered and disordered packings of mono-disperse spheres, in circular, rectangular, and hexagonal planforms. The disordered media was characterized by large ordered regions of close packing with grain boundaries and isolated defects. The defects created regions of larger permeability, and thus spacial variations in the Rayleigh Number, Ra. We define the critical Ra, Ra_{c}, as Ra at the onset of convection in the ordered regions. We find that stable localized convective regions exist around grain-boundaries and defects at Ra < Ra _{c} and remain as pinning sites for the convection patterns in the ordered regions as Ra is increased above Ra_{c} . In ordered media, defects only occurred within a thin region near the vertical

  17. Seminar in Flow Visualization at Lafayette College: Variations on the Hertzberg Effect

    NASA Astrophysics Data System (ADS)

    Rossmann, Jenn Stroud

    2013-11-01

    Flow visualization reveals an invisible world of fluid dynamics, blending scientific investigation and artistic exploration. The resulting images have inspired, and in some cases themselves become appreciated as, art. At Lafayette College, a sophomore-level seminar in The Art and Science of Flow Visualization exposes students to these techniques and the science of fluid mechanics, and to the photographic methods needed to create effective images that are successful both scientifically and artistically. Unlike other courses in flow visualization, this course assumes no a priori familiarity with fluid flow or with photography. The fundamentals of both are taught and practiced in a studio setting. Students are engaged in an interdisciplinary discourse about fluids and physics, photography, scientific ethics, and historical societal responses to science and art. Relevant texts from several disciplines are read, discussed, and responded to in student writing. This seminar approach makes flow visualization and fluid dynamics a natural part of a liberal education. The development, implementation, and assessment of this team-taught course at Lafayette College will be discussed. Support provided by National Science Foundation.

  18. Investigation on the near-wake flow structures of a utility-scale wind turbine using snowflake based flow visualization

    NASA Astrophysics Data System (ADS)

    Dasari, Teja; Toloui, Mostafa; Guala, Michele; Hong, Jiarong

    2015-11-01

    Super-large-scale particle image velocimetry and flow visualization techniques using natural snow particles have been shown as an effective tool to probe the structure of the flow around full-scale wind turbines (Hong et al. Nature Comm. 2014). Here we present a follow-up study based on the data collected during a deployment around the 2.5 MW wind turbine at EOLOS Wind Energy Research Station on April, 4th, 2014. The dataset includes the snow visualization of flow fields from different perspectives in the near wake of the turbine. The motions of the dominant coherent structures including tip, blade root, hub and tower vortices, represented by the snow voids, are examined with the objective of quantifying and correlating their behavior with the meteorological and turbine operating conditions. Some preliminary studies on flow-structure interaction are also performed by correlating the data from strain gauges, accelerometers mounted on the turbine blades, with the flow measurements. The statistical analysis of the motions of blade induced vortices shows a clear impact of atmospheric turbulence and vortex interaction on flow development in the near wake. The result further indicates a strong connection between near-wake vorticity field, turbine operation and structure deformations. The work was supported by National Science Foundation (NSF-CBET-1454259) and the research infrastructure was supported by Department of Energy.

  19. Low-Cost Flow Visualization for a Supersonic Ejector

    NASA Technical Reports Server (NTRS)

    Olden, George W.; Lineberry, David M.; Linn, Christopher A. B.; Landrum, Brian D.; Hawk, Clark W.

    2005-01-01

    Shadowgraph techniques were applied to the cold flow ejector facility at the Propulsion Research Center at the University of Alabama in Huntsville. The setup for the experiments was relatively simple and was accomplished at very little cost. Series of shadowgraph images were taken of both dual nozzle and single nozzle strut based ejectors operating over a range of chamber pressures. The density gradient patterns in the shadowgraphs were compared to pressure data measured along the top and side walls of the mixing duct. The shadowgraph images showed the presence of barrel shocks emanating from the nozzles which at low pressures terminated in Mach disks and at higher pressures extended beyond the barrel shape and reflected off the walls of the duct. Based on pressure data from previous testing, reflected shocks were expected on the walls of the duct. The shadowgraph images confirmed the locations of these reflected shocks on the top wall of the duct. The shadowgraph images also showed the structure change which correlated to a change in pitch of the ejector noise, and corresponded to a change in trend of the duct wall pressure ratio distributions. The images produced from the setup provided insight into the complex flow behavior inside the ejector duct. In addition, the techniques were a valuable tool as an educational device for students.

  20. Visualization of transitional pipe flow using the photochromic tracer method

    NASA Astrophysics Data System (ADS)

    Zalzal, P.; Ojha, M.; Ethier, C. R.; Cobbold, R. S. C.; Johnston, K. W.

    1994-06-01

    Two noninvasive measurement techniques are described for investigating transitional flow in a rigid straight tube. Photochromic trace recordings, representing fluid displacement profiles, were made within the core and at the leading and trailing edges of turbulent slugs generated by a disturbance at the tube inlet. Consistent photochromic trace recordings were made possible through the discovery that Doppler ultrasound can be used to detect the passage of turbulent slugs, thereby allowing precise timing of the photochromic traces. Upstream and downstream Doppler probes enabled the leading and trailing edge velocities of slugs to be measured and also enabled the laminar/turbulent transition regions to be investigated in detail. Trailing edge interface velocities were in excellent agreement with existing data, while leading edge velocities agreed less well. Turbulence generation at the trailing edge appeared to be associated with a localized vortical structure which originated in the near wall region and then grew toward the tube centerline. The generation of this vortex is postulated to be induced by a shear layer instability. Mean velocity profiles obtained from within the core of turbulent slugs were similar to those obtained for fully developed turbulent flow.

  1. Flow visualization study of a two-dimensional representation of the Space Shuttle launch pad configuration

    NASA Technical Reports Server (NTRS)

    Mclachland, B. G.; Zilliac, G. G.; Davis, S. S.

    1987-01-01

    The loss of the Space Shuttle Challenger was caused by the failure of the aft joint O-ring seals in its right solid rocket booster. It has been suggested by several sources that wind conditions through a reduction in temperature of the right solid rocket booster caused by the wind blowing across the cold external tank, played a role in the O-ring failure. To check the plausibility of the wind theory, an experiment was carried out in a water towing tank to visualize the flow past a two-dimensional model representing a cross section of the Space Shuttle launch configuration. The periodic formation of vortices was found to characterize the wake generated by the model. It is suggested that this organized motion in the flow is the dominant mechanism that accomplishes heat transfer from the external tank to the right solid rocket booster. Flow visualization results consisting of photographs that show instantaneous streamline patterns of the flow are presented.

  2. Visualization of flow patterns induced by an impinging jet issuing from a circular planform

    NASA Astrophysics Data System (ADS)

    Saripalli, K. R.

    1983-12-01

    A four-jet impingement flow with application to high-performance VTOL aircraft is investigated. Flow visualization studies were conducted with water as the working medium. Photographs of different cross sections of the flow are presented to describe the properties of the fountain upwash and the stagnation-line patterns. The visualization technique involves the introduction of fluorescein-sodium, a fluorescent dye, into the jet flow and illumination by a sheet of light obtained by spreading a laser beam. Streak-line photographs were also taken using air bubbles as tracer particles. The strength and orientation of the fountain(s) were observed for different heights of the nozzle configuration above the ground and inclination angles of the forward nozzles.

  3. Visualization of the 3-dimensional flow around a model with the aid of a laser knife

    NASA Technical Reports Server (NTRS)

    Borovoy, V. Y.; Ivanov, V. V.; Orlov, A. A.; Kharchenko, V. N.

    1984-01-01

    A method for visualizing the three-dimensional flow around models of various shapes in a wind tunnel at a Mach number of 5 is described. A laser provides a planar light flux such that any plane through the model can be selectively illuminated. The shape of shock waves and separation regions is then determined by the intensity of light scattered by soot particles in the flow.

  4. Quantitative Assessment of Turbulence and Flow Eccentricity in an Aortic Coarctation: Impact of Virtual Interventions.

    PubMed

    Andersson, Magnus; Lantz, Jonas; Ebbers, Tino; Karlsson, Matts

    2015-09-01

    Turbulence and flow eccentricity can be measured by magnetic resonance imaging (MRI) and may play an important role in the pathogenesis of numerous cardiovascular diseases. In the present study, we propose quantitative techniques to assess turbulent kinetic energy (TKE) and flow eccentricity that could assist in the evaluation and treatment of stenotic severities. These hemodynamic parameters were studied in a pre-treated aortic coarctation (CoA) and after several virtual interventions using computational fluid dynamics (CFD), to demonstrate the effect of different dilatation options on the flow field. Patient-specific geometry and flow conditions were derived from MRI data. The unsteady pulsatile flow was resolved by large eddy simulation including non-Newtonian blood rheology. Results showed an inverse asymptotic relationship between the total amount of TKE and degree of dilatation of the stenosis, where turbulent flow proximal the constriction limits the possible improvement by treating the CoA alone. Spatiotemporal maps of TKE and flow eccentricity could be linked to the characteristics of the jet, where improved flow conditions were favored by an eccentric dilatation of the CoA. By including these flow markers into a combined MRI-CFD intervention framework, CoA therapy has not only the possibility to produce predictions via simulation, but can also be validated pre- and immediate post treatment, as well as during follow-up studies. PMID:26577361

  5. Visualization of complex flow fields, with application to the interpretation of colour flow Doppler images.

    PubMed

    Vera, N; Steinman, D A; Ethier, C R; Johnston, K W; Cobbold, R S

    1992-01-01

    The interpretation of colour flow Doppler images in regions of complex flow can be difficult. To aid in such interpretations, we have developed software which accepts as input the results of a fluid flow simulation program and produces simulated colour flow Doppler images on a workstation. This allows direct comparison between well-described flow fields and colour flow Doppler images. Application of this approach is demonstrated for flow in a two-dimensional model of a distal graft-to-vessel anastomosis, and the interpretation of the results for three-dimensional flows is briefly discussed. In addition, a method for presenting two-dimensional (vectorial) velocity data via colour coding is presented.

  6. Attention to quantitative and configural properties of abstract visual patterns by children and adults.

    PubMed

    Mendelson, M J

    1984-10-01

    Students in grades 2, 4, 6, and college sorted abstract visual patterns that varied both in amount of contour and in the type of visual organization (unstructured, simple symmetries, multiple symmetries, and rotational organization). The subjects were told to put the patterns into rows so that all the patterns in a row were "alike in some way," with no limits placed either on the number of rows or on the number of patterns in a row. Second graders sorted mainly on the basis of amount of contour and less so with reference to multiple types of visual organization. Fourth and sixth graders used contour as a sorting criterion less than second graders; moreover, they sorted with reference to all types of visual structure. As a group, college students sorted exclusively on the basis of structure. The data were taken as evidence that children attend to both amount of contour and visual organization, but that attention to visual structure increases with age. PMID:6510055

  7. NADH augments blood flow in physiologically activated retina and visual cortex

    NASA Astrophysics Data System (ADS)

    Ido, Yasuo; Chang, Katherine; Williamson, Joseph R.

    2004-01-01

    The mechanism(s) that increase retinal and visual cortex blood flows in response to visual stimulation are poorly understood. We tested the hypothesis that increased transfer of electrons and protons from glucose to cytosolic free NAD+, reducing it to NADH, evoked by increased energy metabolism, fuels redox-signaling pathways that augment flow. The near-equilibrium between free cytosolic NADH/NAD+ and lactate/pyruvate ratios established by lactate dehydrogenase predicts that transfer of additional electrons and protons from injected lactate to NAD+ will augment the elevated blood flows in stimulated retina and cortex, whereas transfer of electrons and protons from NADH to injected pyruvate will attenuate the elevated flows. These predictions were tested and confirmed in rats. Increased flows evoked by stimulation also were prevented by inhibition of nitric oxide synthase. These findings support an important role for cytosolic free NADH in fueling a signaling cascade that increases NO production, which augments blood flow in photostimulated retina and visual cortex.

  8. Design and synthesis of target-responsive aptamer-cross-linked hydrogel for visual quantitative detection of ochratoxin A.

    PubMed

    Liu, Rudi; Huang, Yishun; Ma, Yanli; Jia, Shasha; Gao, Mingxuan; Li, Jiuxing; Zhang, Huimin; Xu, Dunming; Wu, Min; Chen, Yan; Zhu, Zhi; Yang, Chaoyong

    2015-04-01

    A target-responsive aptamer-cross-linked hydrogel was designed and synthesized for portable and visual quantitative detection of the toxin Ochratoxin A (OTA), which occurs in food and beverages. The hydrogel network forms by hybridization between one designed DNA strand containing the OTA aptamer and two complementary DNA strands grafting on linear polyacrylamide chains. Upon the introduction of OTA, the aptamer binds with OTA, leading to the dissociation of the hydrogel, followed by release of the preloaded gold nanoparticles (AuNPs), which can be observed by the naked eye. To enable sensitive visual and quantitative detection, we encapsulated Au@Pt core-shell nanoparticles (Au@PtNPs) in the hydrogel to generate quantitative readout in a volumetric bar-chart chip (V-Chip). In the V-Chip, Au@PtNPs catalyzes the oxidation of H2O2 to generate O2, which induces movement of an ink bar to a concentration-dependent distance for visual quantitative readout. Furthermore, to improve the detection limit in complex real samples, we introduced an immunoaffinity column (IAC) of OTA to enrich OTA from beer. After the enrichment, as low as 1.27 nM (0.51 ppb) OTA can be detected by the V-Chip, which satisfies the test requirement (2.0 ppb) by the European Commission. The integration of a target-responsive hydrogel with portable enrichment by IAC, as well as signal amplification and quantitative readout by a simple microfluidic device, offers a new method for portable detection of food safety hazard toxin OTA.

  9. Optic Flow Dominates Visual Scene Polarity in Causing Adaptive Modification of Locomotor Trajectory

    NASA Technical Reports Server (NTRS)

    Nomura, Y.; Mulavara, A. P.; Richards, J. T.; Brady, R.; Bloomberg, Jacob J.

    2005-01-01

    Locomotion and posture are influenced and controlled by vestibular, visual and somatosensory information. Optic flow and scene polarity are two characteristics of a visual scene that have been identified as being critical in how they affect perceived body orientation and self-motion. The goal of this study was to determine the role of optic flow and visual scene polarity on adaptive modification in locomotor trajectory. Two computer-generated virtual reality scenes were shown to subjects during 20 minutes of treadmill walking. One scene was a highly polarized scene while the other was composed of objects displayed in a non-polarized fashion. Both virtual scenes depicted constant rate self-motion equivalent to walking counterclockwise around the perimeter of a room. Subjects performed Stepping Tests blindfolded before and after scene exposure to assess adaptive changes in locomotor trajectory. Subjects showed a significant difference in heading direction, between pre and post adaptation stepping tests, when exposed to either scene during treadmill walking. However, there was no significant difference in the subjects heading direction between the two visual scene polarity conditions. Therefore, it was inferred from these data that optic flow has a greater role than visual polarity in influencing adaptive locomotor function.

  10. Magnetic fingerprints of rolling cells for quantitative flow cytometry in whole blood

    PubMed Central

    Reisbeck, Mathias; Helou, Michael Johannes; Richter, Lukas; Kappes, Barbara; Friedrich, Oliver; Hayden, Oliver

    2016-01-01

    Over the past 50 years, flow cytometry has had a profound impact on preclinical and clinical applications requiring single cell function information for counting, sub-typing and quantification of epitope expression. At the same time, the workflow complexity and high costs of such optical systems still limit flow cytometry applications to specialized laboratories. Here, we present a quantitative magnetic flow cytometer that incorporates in situ magnetophoretic cell focusing for highly accurate and reproducible rolling of the cellular targets over giant magnetoresistance sensing elements. Time-of-flight analysis is used to unveil quantitative single cell information contained in its magnetic fingerprint. Furthermore, we used erythrocytes as a biological model to validate our methodology with respect to precise analysis of the hydrodynamic cell diameter, quantification of binding capacity of immunomagnetic labels, and discrimination of cell morphology. The extracted time-of-flight information should enable point-of-care quantitative flow cytometry in whole blood for clinical applications, such as immunology and primary hemostasis. PMID:27596736

  11. Magnetic fingerprints of rolling cells for quantitative flow cytometry in whole blood.

    PubMed

    Reisbeck, Mathias; Helou, Michael Johannes; Richter, Lukas; Kappes, Barbara; Friedrich, Oliver; Hayden, Oliver

    2016-01-01

    Over the past 50 years, flow cytometry has had a profound impact on preclinical and clinical applications requiring single cell function information for counting, sub-typing and quantification of epitope expression. At the same time, the workflow complexity and high costs of such optical systems still limit flow cytometry applications to specialized laboratories. Here, we present a quantitative magnetic flow cytometer that incorporates in situ magnetophoretic cell focusing for highly accurate and reproducible rolling of the cellular targets over giant magnetoresistance sensing elements. Time-of-flight analysis is used to unveil quantitative single cell information contained in its magnetic fingerprint. Furthermore, we used erythrocytes as a biological model to validate our methodology with respect to precise analysis of the hydrodynamic cell diameter, quantification of binding capacity of immunomagnetic labels, and discrimination of cell morphology. The extracted time-of-flight information should enable point-of-care quantitative flow cytometry in whole blood for clinical applications, such as immunology and primary hemostasis. PMID:27596736

  12. Magnetic fingerprints of rolling cells for quantitative flow cytometry in whole blood

    NASA Astrophysics Data System (ADS)

    Reisbeck, Mathias; Helou, Michael Johannes; Richter, Lukas; Kappes, Barbara; Friedrich, Oliver; Hayden, Oliver

    2016-09-01

    Over the past 50 years, flow cytometry has had a profound impact on preclinical and clinical applications requiring single cell function information for counting, sub-typing and quantification of epitope expression. At the same time, the workflow complexity and high costs of such optical systems still limit flow cytometry applications to specialized laboratories. Here, we present a quantitative magnetic flow cytometer that incorporates in situ magnetophoretic cell focusing for highly accurate and reproducible rolling of the cellular targets over giant magnetoresistance sensing elements. Time-of-flight analysis is used to unveil quantitative single cell information contained in its magnetic fingerprint. Furthermore, we used erythrocytes as a biological model to validate our methodology with respect to precise analysis of the hydrodynamic cell diameter, quantification of binding capacity of immunomagnetic labels, and discrimination of cell morphology. The extracted time-of-flight information should enable point-of-care quantitative flow cytometry in whole blood for clinical applications, such as immunology and primary hemostasis.

  13. Flow visualization study of the horseshoe vortex in a turbine stator cascade

    NASA Technical Reports Server (NTRS)

    Gaugler, R. E.; Russell, L. M.

    1982-01-01

    Flow visualization techniques were used to show the behavior of the horseshoe vortex in a large scale turbine stator cascade. Oil drops on the end wall surface flowed in response to local shear stresses, indicating the limiting flow streamlines at the surface. Smoke injected into the flow and photographed showed time averaged flow behavior. Neutrally bouyant helium filled soap bubbles followed the flow and showed up on photographs as streaks, indicating the paths followed by individual fluid particles. Preliminary attempts to control the vortex were made by injecting air through control jets drilled in the end wall near the vane leading edge. Seventeen different hole locations were tested, one at a time, and the effect of the control jets on the path follwed by smoke in the boundary layer was recorded photographically.

  14. Flow visualization study of the horseshoe vortex in a turbine stator cascade

    NASA Astrophysics Data System (ADS)

    Gaugler, R. E.; Russell, L. M.

    1982-06-01

    Flow visualization techniques were used to show the behavior of the horseshoe vortex in a large scale turbine stator cascade. Oil drops on the end wall surface flowed in response to local shear stresses, indicating the limiting flow streamlines at the surface. Smoke injected into the flow and photographed showed time averaged flow behavior. Neutrally bouyant helium filled soap bubbles followed the flow and showed up on photographs as streaks, indicating the paths followed by individual fluid particles. Preliminary attempts to control the vortex were made by injecting air through control jets drilled in the end wall near the vane leading edge. Seventeen different hole locations were tested, one at a time, and the effect of the control jets on the path follwed by smoke in the boundary layer was recorded photographically.

  15. Flow visualization of a non-contact transport device by Coanda effect

    NASA Astrophysics Data System (ADS)

    Iki, Norihiko; Abe, Hiroyuki; Okada, Takashi

    2014-08-01

    AIST proposes new technology of non-contact transport device utilizing Coanda effect. A proposed non-contact transport device has a cylindrical body and circular slit for air. The air flow around non-contact device is turbulent and its flow pattern depends on the injection condition. Therefore we tried visualization of the air flow around non -contact device as the first step of PIV measurement. Several tracer particles were tried such as TiO2 particles, water droplets, potatoes starch, rice starch, corn starch. Hot-wire anemometer is employed to velocity measurement. TiO2 particles deposit inside of a slit and clogging of a slit occurs frequently. Potato starch particles do not clog a slit but they are too heavy to trace slow flow area. Water droplets by ultrasonic atomization also deposit inside of slit but they are useful to visualize flow pattern around a non-contact transport device by being supplied from circumference. Coanda effect of proposed non-contact transport device was confirmed and injected air flow pattern switches by a work. Air flow around non-contact trance port device is turbulent and its velocity range is wide. Therefore flow measurement by tracer part icle has traceability issue. Suitable tracer and exposure condition depends on target area.

  16. Flow-Visualization Techniques Used at High Speed by Configuration Aerodynamics Wind-Tunnel-Test Team

    NASA Technical Reports Server (NTRS)

    Lamar, John E. (Editor)

    2001-01-01

    This paper summarizes a variety of optically based flow-visualization techniques used for high-speed research by the Configuration Aerodynamics Wind-Tunnel Test Team of the High-Speed Research Program during its tenure. The work of other national experts is included for completeness. Details of each technique with applications and status in various national wind tunnels are given.

  17. The Impact of a Visual Imagery Intervention on Army ROTC Cadets' Marksmanship Performance and Flow Experiences

    ERIC Educational Resources Information Center

    Rakes, Edward Lee

    2012-01-01

    This investigation used an experimental design to examine how a visual imagery intervention and two levels of challenge would affect the flow experiences and performance of cadets engaged in Army ROTC marksmanship training. I employed MANCOVA analyses, with gender and prior marksmanship training experience as covariates, to assess cadets' (n =…

  18. An improvement of the smoke-wire method of flow visualization

    NASA Astrophysics Data System (ADS)

    Fukamachi, N.; Ohya, Y.; Nakamura, Y.

    1991-01-01

    One of the serious drawbacks of the smoke-wire method, which is a simple but very useful means of flow visualization in low-speed wind-tunnel studies, is the short duration of the smoke. In this paper, it is shown that the duration time can be greatly increased by mixing a fine metal powder with the oil.

  19. OpinionFlow: Visual Analysis of Opinion Diffusion on Social Media.

    PubMed

    Wu, Yingcai; Liu, Shixia; Yan, Kai; Liu, Mengchen; Wu, Fangzhao

    2014-12-01

    It is important for many different applications such as government and business intelligence to analyze and explore the diffusion of public opinions on social media. However, the rapid propagation and great diversity of public opinions on social media pose great challenges to effective analysis of opinion diffusion. In this paper, we introduce a visual analysis system called OpinionFlow to empower analysts to detect opinion propagation patterns and glean insights. Inspired by the information diffusion model and the theory of selective exposure, we develop an opinion diffusion model to approximate opinion propagation among Twitter users. Accordingly, we design an opinion flow visualization that combines a Sankey graph with a tailored density map in one view to visually convey diffusion of opinions among many users. A stacked tree is used to allow analysts to select topics of interest at different levels. The stacked tree is synchronized with the opinion flow visualization to help users examine and compare diffusion patterns across topics. Experiments and case studies on Twitter data demonstrate the effectiveness and usability of OpinionFlow. PMID:26356890

  20. OpinionFlow: Visual Analysis of Opinion Diffusion on Social Media.

    PubMed

    Wu, Yingcai; Liu, Shixia; Yan, Kai; Liu, Mengchen; Wu, Fangzhao

    2014-12-01

    It is important for many different applications such as government and business intelligence to analyze and explore the diffusion of public opinions on social media. However, the rapid propagation and great diversity of public opinions on social media pose great challenges to effective analysis of opinion diffusion. In this paper, we introduce a visual analysis system called OpinionFlow to empower analysts to detect opinion propagation patterns and glean insights. Inspired by the information diffusion model and the theory of selective exposure, we develop an opinion diffusion model to approximate opinion propagation among Twitter users. Accordingly, we design an opinion flow visualization that combines a Sankey graph with a tailored density map in one view to visually convey diffusion of opinions among many users. A stacked tree is used to allow analysts to select topics of interest at different levels. The stacked tree is synchronized with the opinion flow visualization to help users examine and compare diffusion patterns across topics. Experiments and case studies on Twitter data demonstrate the effectiveness and usability of OpinionFlow.

  1. Real-Time Aerodynamic Flow and Data Visualization in an Interactive Virtual Environment

    NASA Technical Reports Server (NTRS)

    Schwartz, Richard J.; Fleming, Gary A.

    2005-01-01

    Significant advances have been made to non-intrusive flow field diagnostics in the past decade. Camera based techniques are now capable of determining physical qualities such as surface deformation, surface pressure and temperature, flow velocities, and molecular species concentration. In each case, extracting the pertinent information from the large volume of acquired data requires powerful and efficient data visualization tools. The additional requirement for real time visualization is fueled by an increased emphasis on minimizing test time in expensive facilities. This paper will address a capability titled LiveView3D, which is the first step in the development phase of an in depth, real time data visualization and analysis tool for use in aerospace testing facilities.

  2. Visualization and finite element analysis of pulsatile flow in models of the abdominal aortic aneurysm.

    PubMed

    Fukushima, T; Matsuzawa, T; Homma, T

    1989-01-01

    Pulsatile flows in glass models simulating fusiform and lateral saccular aneurysms were investigated by a flow visualization method. When resting fluid starts to flow, the initial fluid motion is practically irrotational. After a short period of time, the flow began to separate from the proximal wall of the aneurysm. Then the separation bubble or vortex grew rapidly in size and filled the whole area of the aneurysm circumferentially. During this period of time, the center of the vortex moved from the proximal end to the distal point of the aneurysm. The transient reversal flow, for instance, which may occur at the end of the ejection period, passed between the wall of the aneurysm and the centrally located vortex. When the rate and pulsatile frequency of flow were high, the vortex broke down into highly disturbed flow (or turbulence) at the distal portion of the aneurysm. The same effect was observed when the length of the aneurysm was increased. A reduction in pulsatile amplitude made the flow pattern close to that in steady flow. A finite element analysis was made to obtain velocity and pressure fields in pulsatile flow through a tube with an axisymmetric expansion. Calculations were performed with the pulsatile flows used in the visualization experiment in order to study the effects of change in the pulsatile wave form by keeping the time-mean Reynolds number and Womersley's parameter unchanged. Calculated instantaneous patterns of velocity field and stream lines agreed well with the experimental results. The appearance and disappearance of the vortex in the dilated portion and its development resulted in complex distributions of pressure and shear fields. Locally minimum and maximum values of wall shear stress occurred at points just upstream and downstream of the distal end of the expansion when the flow rate reached its peak. PMID:2605323

  3. A Quantitative Analysis of the Work Experiences of Adults with Visual Impairments in Nigeria

    ERIC Educational Resources Information Center

    Wolffe, Karen E.; Ajuwon, Paul M.; Kelly, Stacy M.

    2013-01-01

    Introduction: Worldwide, people with visual impairments often struggle to gain employment. This study attempts to closely evaluate the work experiences of employed individuals with visual impairments living in one of the world's most populous developing nations, Nigeria. Methods: The researchers developed a questionnaire that assessed…

  4. Azimuthal instability of the interface in a shear banded flow by direct visual observation.

    PubMed

    Decruppe, J P; Bécu, L; Greffier, O; Fazel, N

    2010-12-17

    The stability of the shear banded flow of a Maxwellian fluid is studied from an experimental point of view using rheology and flow visualization with polarized light. We show that the one-layer homogeneous flow cannot sustain shear rates corresponding to the end of the stress plateau. The high shear rate branch is not found and the shear stress oscillates at the end of the plateau. An azimuthal instability appears: the shear induced band becomes unstable and the interface between the two bands undulates in time and space with a period τ, a wavelength λ and a wave vector k parallel to the direction of the tangential velocity.

  5. The state of the art of conventional flow visualization techniques for wind tunnel testing

    NASA Technical Reports Server (NTRS)

    Settles, G. S.

    1982-01-01

    Conventional wind tunnel flow visualization techniques which consist of surface flow methods, tracers, and optical methods are presented. Different surface flow methods are outlined: (1) liquid films (oil and fluorescent dye and UV lighting, renewable film via porous dispenser in model, volatile carrier fluid, cryogenic colored oil dots, oil film interferometry); (2) reactive surface treatment (reactive gas injection, reversible dye); (3) transition and heat transfer detectors (evaporation, sublimation, liquid crystals, phase change paints, IR thermography); and (4) tufts (fluorescent mini tufts, cryogenic suitability). Other methods are smoke wire techniques, vapor screens, and optical methods.

  6. Quantitative polarization and flow evaluation of choroid and sclera by multifunctional Jones matrix optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Sugiyama, S.; Hong, Y.-J.; Kasaragod, D.; Makita, S.; Miura, M.; Ikuno, Y.; Yasuno, Y.

    2016-03-01

    Quantitative evaluation of optical properties of choroid and sclera are performed by multifunctional optical coherence tomography. Five normal eyes, five glaucoma eyes and one choroidal atrophy eye are examined. The refractive error was found to be correlated with choroidal birefringence, polarization uniformity, and flow in addition to scleral birefringence among normal eyes. The significant differences were observed between the normal and the glaucoma eyes, as for choroidal polarization uniformity, flow and scleral birefringence. An automatic segmentation algorithm of retinal pigment epithelium and chorioscleral interface based on multifunctional signals is also presented.

  7. In-flight flow visualization and pressure measurements at low speeds on the NASA F-18 high alpha research vehicle

    NASA Technical Reports Server (NTRS)

    Delfrate, John H.; Fisher, David F.; Zuniga, Fanny A.

    1991-01-01

    Inflight results from surface and off surface flow visualizations and from extensive pressure distributions document the vortical flow on the leading edge extensions (LEXs) and forebody of the NASA F-18 high alpha research vehicle (HARV) for low speeds and angles of attack up to 50 deg. Surface flow visualization data, obtained using the emitted fluid technique, were used to define separation lines and laminar separation bubbles (LSB). Off surface flow visualization data, obtained by smoke injection, were used to document both the path of the vortex cores and the location of vortex core breakdown. The location of vortex core breakdown correlated well with the loss of suction pressure on the LEX and with the flow visualization results from ground facilities. Surface flow separation lines on the LEX and forebody corresponded well with the end of pressure recovery under the vortical flows. Correlation of the pressures with wind tunnel results show fair to good correlation.

  8. In-flight flow visualization with pressure measurements at low speeds on the NASA F-18 high alpha research vehicle

    NASA Technical Reports Server (NTRS)

    Delfrate, John H.; Fisher, David F.; Zuniga, Fanny A.

    1990-01-01

    In-flight results from surface and off-surface flow visualizations and from extensive pressure distributions document the vortical flow on the leading edge extensions (LEX) and forebody of the NASA F-18 high alpha research vehicle for low speeds and angles of attack up to 50 degs. Surface flow visualization data, obtained using the emitted fluid technique, were used to define separation lines and laminar separation bubbles. Off-surface flow visualization data, obtained by smoke injection, were used to document both the path of the vortex cores and the location of vortex core breakdown. The location of vortex core breakdown correlated well with the loss of suction pressure on the LEX and with the flow visualization results from ground facilities. Surface flow separation lines on the LEX and forebody corresponded well with the end of pressure recovery under the vortical flows. Correlation of the pressures with wind tunnel results show fair to good correlation.

  9. An enzyme-amplified lateral flow strip biosensor for visual detection of microRNA-224.

    PubMed

    Gao, Xuefei; Xu, Li-Ping; Wu, Tingting; Wen, Yongqiang; Ma, Xinlei; Zhang, Xueji

    2016-01-01

    An enzyme-based dual-labeled nanoprobe is designed to fabricate a sensitive enzyme-amplified lateral flow biosensor for visual detection of mircoRNA-224 (miRNA-224). The recognition DNA probe (detection probe) and signal amplification enzyme (Horseradish peroxidase, HRP) are immobilized on gold nanoparticle (GNPs) surface, simultaneously. The capture DNA probes are immobilized on the test zone of the lateral flow biosensor. When miRNA-224 is present, the enzyme-based dual-labeled nanoprobes will be captured by forming the "sandwich structure" on the test zone of the lateral flow biosensor, enabling the visual detection for miRNA-224. Sensitivity is amplified by applying the 3,3,5,5-tetramethylbenzidine enzymatic substrate (TMB/H2O2 enzymatic substrate) onto the test zone. The enzymatic reactions between the HRP and the TMB/H2O2 enzymatic substrate will produce blue products, which deposit on the nanoprobe surface to enhance the visual effect and the corresponding response intensities of the test zone. This enzyme-amplified lateral flow biosensor shows a low limit of detection (LOD) (7.5 pM) toward miRNA-224 in the buffer solution, which is improved by 10-fold than that of the single-labeled lateral flow biosensor. This biosensor has been successfully used for the detection of the target miRNA-224 detection in A549 cell lysate.

  10. Exploratory flow visualization investigation of mast-mounted sights in presence of a rotor

    NASA Technical Reports Server (NTRS)

    Ghee, Terence A.; Kelley, Henry L.

    1995-01-01

    A flow visualization investigation with a laser light sheet system was conducted on a 27-percent-scale AH-64 attack helicopter model fitted with two mast-mounted sights in the langley 14- by 22-foot subsonic tunnel. The investigation was conducted to identify aerodynamic phenomena that may have contributed to adverse vibration encountered during full-scale flight of the AH-64D apache/longbow helicopter with an asymmetric mast-mounted sight. Symmetric and asymmetric mast-mounted sights oriented at several skew angles were tested at simulated forward and rearward flight speeds of 30 and 45 knots. A laser light sheet system was used to visualize the flow in planes parallel to and perpendicular to the free-stream flow. Analysis of these flow visualization data identified frequencies of flow patterns in the wake shed from the sight, the streamline angle at the sight, and the location where the shed wake crossed the rotor plane. Differences in wake structure were observed between the sight configurations and various skew angles. Analysis of lateral light sheet plane data implied significant vortex structure in the wake of the asymmetric mast-mounted sight in the configuration that produced maximum in-flight vibration. The data showed no significant vortex structure in the wake of the asymmetric and symmetric configurations that produced no increase in in-flight adverse vibration.

  11. Forebody Flow Visualization on the F-18 HARV with Actuated Forebody Strakes

    NASA Technical Reports Server (NTRS)

    Fisher, David F.; Murri, Daniel G.

    1998-01-01

    Off-surface smoke flow visualization and extensive pressure measurements were obtained on the forebody of the NASA F-18 High Alpha Research Vehicle equipped with actuated forebody strakes. Test points at alpha = 50 deg. were examined in which only one strake was deflected or in which both strakes were deflected differentially. The forebody pressures were integrated to obtain forebody yawing moments. Results showed that small single strake deflections can cause an undesirable yawing moment reversal. At alpha = 50 deg., this reversal was corrected by deploying both strakes at 20 deg. initially, then differentially from 20 deg. to create a yawing moment. The off-surface flow visualization showed that in the case of the small single strake deflection, the resulting forebody/strake vortex remained close to the surface and caused accelerated flow and increased suction pressures on the deflected side. When both strakes were deflected differentially, two forebody/strake vortices were present. The forebody/strake vortex from the larger deflection would lift from the surface while the other would remain close to the surface. The nearer forebody/strake vortex would cause greater flow acceleration, higher suction pressures and a yawing moment on that side of the forebody. Flow visualization provided a clear description of the strake vortices fluid mechanics.

  12. MotionFlow: Visual Abstraction and Aggregation of Sequential Patterns in Human Motion Tracking Data.

    PubMed

    Jang, Sujin; Elmqvist, Niklas; Ramani, Karthik

    2016-01-01

    Pattern analysis of human motions, which is useful in many research areas, requires understanding and comparison of different styles of motion patterns. However, working with human motion tracking data to support such analysis poses great challenges. In this paper, we propose MotionFlow, a visual analytics system that provides an effective overview of various motion patterns based on an interactive flow visualization. This visualization formulates a motion sequence as transitions between static poses, and aggregates these sequences into a tree diagram to construct a set of motion patterns. The system also allows the users to directly reflect the context of data and their perception of pose similarities in generating representative pose states. We provide local and global controls over the partition-based clustering process. To support the users in organizing unstructured motion data into pattern groups, we designed a set of interactions that enables searching for similar motion sequences from the data, detailed exploration of data subsets, and creating and modifying the group of motion patterns. To evaluate the usability of MotionFlow, we conducted a user study with six researchers with expertise in gesture-based interaction design. They used MotionFlow to explore and organize unstructured motion tracking data. Results show that the researchers were able to easily learn how to use MotionFlow, and the system effectively supported their pattern analysis activities, including leveraging their perception and domain knowledge.

  13. Comparison of blood flow models and acquisitions for quantitative myocardial perfusion estimation from dynamic CT.

    PubMed

    Bindschadler, Michael; Modgil, Dimple; Branch, Kelley R; La Riviere, Patrick J; Alessio, Adam M

    2014-04-01

    Myocardial blood flow (MBF) can be estimated from dynamic contrast enhanced (DCE) cardiac CT acquisitions, leading to quantitative assessment of regional perfusion. The need for low radiation dose and the lack of consensus on MBF estimation methods motivates this study to refine the selection of acquisition protocols and models for CT-derived MBF. DCE cardiac CT acquisitions were simulated for a range of flow states (MBF = 0.5, 1, 2, 3 ml (min g)(-1), cardiac output = 3, 5, 8 L min(-1)). Patient kinetics were generated by a mathematical model of iodine exchange incorporating numerous physiological features including heterogenenous microvascular flow, permeability and capillary contrast gradients. CT acquisitions were simulated for multiple realizations of realistic x-ray flux levels. CT acquisitions that reduce radiation exposure were implemented by varying both temporal sampling (1, 2, and 3 s sampling intervals) and tube currents (140, 70, and 25 mAs). For all acquisitions, we compared three quantitative MBF estimation methods (two-compartment model, an axially-distributed model, and the adiabatic approximation to the tissue homogeneous model) and a qualitative slope-based method. In total, over 11 000 time attenuation curves were used to evaluate MBF estimation in multiple patient and imaging scenarios. After iodine-based beam hardening correction, the slope method consistently underestimated flow by on average 47.5% and the quantitative models provided estimates with less than 6.5% average bias and increasing variance with increasing dose reductions. The three quantitative models performed equally well, offering estimates with essentially identical root mean squared error (RMSE) for matched acquisitions. MBF estimates using the qualitative slope method were inferior in terms of bias and RMSE compared to the quantitative methods. MBF estimate error was equal at matched dose reductions for all quantitative methods and range of techniques evaluated. This

  14. Comparison of blood flow models and acquisitions for quantitative myocardial perfusion estimation from dynamic CT

    NASA Astrophysics Data System (ADS)

    Bindschadler, Michael; Modgil, Dimple; Branch, Kelley R.; La Riviere, Patrick J.; Alessio, Adam M.

    2014-04-01

    Myocardial blood flow (MBF) can be estimated from dynamic contrast enhanced (DCE) cardiac CT acquisitions, leading to quantitative assessment of regional perfusion. The need for low radiation dose and the lack of consensus on MBF estimation methods motivates this study to refine the selection of acquisition protocols and models for CT-derived MBF. DCE cardiac CT acquisitions were simulated for a range of flow states (MBF = 0.5, 1, 2, 3 ml (min g)-1, cardiac output = 3, 5, 8 L min-1). Patient kinetics were generated by a mathematical model of iodine exchange incorporating numerous physiological features including heterogenenous microvascular flow, permeability and capillary contrast gradients. CT acquisitions were simulated for multiple realizations of realistic x-ray flux levels. CT acquisitions that reduce radiation exposure were implemented by varying both temporal sampling (1, 2, and 3 s sampling intervals) and tube currents (140, 70, and 25 mAs). For all acquisitions, we compared three quantitative MBF estimation methods (two-compartment model, an axially-distributed model, and the adiabatic approximation to the tissue homogeneous model) and a qualitative slope-based method. In total, over 11 000 time attenuation curves were used to evaluate MBF estimation in multiple patient and imaging scenarios. After iodine-based beam hardening correction, the slope method consistently underestimated flow by on average 47.5% and the quantitative models provided estimates with less than 6.5% average bias and increasing variance with increasing dose reductions. The three quantitative models performed equally well, offering estimates with essentially identical root mean squared error (RMSE) for matched acquisitions. MBF estimates using the qualitative slope method were inferior in terms of bias and RMSE compared to the quantitative methods. MBF estimate error was equal at matched dose reductions for all quantitative methods and range of techniques evaluated. This suggests that

  15. A quantitative method for measuring innate phagocytosis by human monocytes using real-time flow cytometry.

    PubMed

    Gu, Ben J; Sun, Chun; Fuller, Stephen; Skarratt, Kristen K; Petrou, Steven; Wiley, James S

    2014-04-01

    Phagocytosis is central to immunity however a rapid and standardized method is much needed for quantitative assessment of the phagocytic process. We describe a real-time flow cytometric method to quantitate the phagocytosis of fluorescent latex beads by human monocytes in serum-free conditions. Effects of buffer composition, temperature, pH, and bead surface on phagocytic rate are described. The innate phagocytic ability of human monocytes from single subjects measured by this method was relatively stable over many months although phagocytosis rate varied as much as two-fold between individuals. Comparable results were obtained with a simplified method using several mL of whole blood which is suitable for routine clinical application. This method also allows two-color flow cytometric measurement of cytosolic calcium levels during the phagocytic uptake of fluorescent beads.

  16. Right Heart 4DMRI Flow Visualization in Normal and Hypertensive subjects

    NASA Astrophysics Data System (ADS)

    Hertzberg, Jean; Browning, James; Fenster, Brett; Schroeder, Joyce

    2015-11-01

    Recent advances in time-resolved 3D cardiac magnetic resonance imaging (4DMRI) have allowed for the 3-dimensional characterization of blood flow in the right ventricle (RV) and right atrium (RA). In this talk, an overview of a large, ongoing, multi-disciplinary investigation of 4D right heart hemodynamics in normal and pathologic patients is given, as well as lessons learned from 4DMRI cardiac research. Time-resolved visualization techniques for understanding and communicating complex right heart flow structures throughout the cardiac cycle are presented. Finally, a qualitative visual comparison of 3D flow structures in the vena cava, RA, and RV between healthy subjects and pulmonary hypertensive patients is presented.

  17. Flow Visualization at Cryogenic Conditions Using a Modified Pressure Sensitive Paint Approach

    NASA Technical Reports Server (NTRS)

    Watkins, A. Neal; Goad, William K.; Obara, Clifford J.; Sprinkle, Danny R.; Campbell, Richard L.; Carter, Melissa B.; Pendergraft, Odis C., Jr.; Bell, James H.; Ingram, JoAnne L.; Oglesby, Donald M.

    2005-01-01

    A modification to the Pressure Sensitive Paint (PSP) method was used to visualize streamlines on a Blended Wing Body (BWB) model at full-scale flight Reynolds numbers. In order to achieve these conditions, the tests were carried out in the National Transonic Facility operating under cryogenic conditions in a nitrogen environment. Oxygen is required for conventional PSP measurements, and several tests have been successfully completed in nitrogen environments by injecting small amounts (typically < 3000 ppm) of oxygen into the flow. A similar technique was employed here, except that air was purged through pressure tap orifices already existent on the model surface, resulting in changes in the PSP wherever oxygen was present. The results agree quite well with predicted results obtained through computational fluid dynamics analysis (CFD), which show this to be a viable technique for visualizing flows without resorting to more invasive procedures such as oil flow or minitufts.

  18. Hot gas ingestion characteristics and flow visualization of a vectored thrust STOVL concept

    NASA Technical Reports Server (NTRS)

    Johns, Albert L.; Neiner, George H.; Bencic, Timothy J.; Flood, Joseph D.; Amuedo, Kurt C.; Strock, Thomas W.; Williams, Ben R.

    1990-01-01

    The study presents results obtained at the compressor face of a 9.2-percent scale vectored thrust model in ground effects from Phases I and II of a test program to evaluate the hot ingestion phenomena and control techniques, and to conduct flow visualization of the model flowfield in and out of ground effects, respectively. A description of the model, facility, a new model support system, and a sheet laser illumination system are provided. The findings contain the compressor face pressure and temperature distortions, compressor face temperature rise, and the environmental effects of the hot gas. The environmental effects include the ground plane temperature and pressure distributions, model airframe heating, and the location of the ground flow separation. Results from the sheet laser flow visualization test are also presented.

  19. Fast blood flow visualization of high-resolution laser speckle imaging data using graphics processing unit.

    PubMed

    Liu, Shusen; Li, Pengcheng; Luo, Qingming

    2008-09-15

    Laser speckle contrast analysis (LASCA) is a non-invasive, full-field optical technique that produces two-dimensional map of blood flow in biological tissue by analyzing speckle images captured by CCD camera. Due to the heavy computation required for speckle contrast analysis, video frame rate visualization of blood flow which is essentially important for medical usage is hardly achieved for the high-resolution image data by using the CPU (Central Processing Unit) of an ordinary PC (Personal Computer). In this paper, we introduced GPU (Graphics Processing Unit) into our data processing framework of laser speckle contrast imaging to achieve fast and high-resolution blood flow visualization on PCs by exploiting the high floating-point processing power of commodity graphics hardware. By using GPU, a 12-60 fold performance enhancement is obtained in comparison to the optimized CPU implementations.

  20. DecisionFlow: Visual Analytics for High-Dimensional Temporal Event Sequence Data.

    PubMed

    Gotz, David; Stavropoulos, Harry

    2014-12-01

    Temporal event sequence data is increasingly commonplace, with applications ranging from electronic medical records to financial transactions to social media activity. Previously developed techniques have focused on low-dimensional datasets (e.g., with less than 20 distinct event types). Real-world datasets are often far more complex. This paper describes DecisionFlow, a visual analysis technique designed to support the analysis of high-dimensional temporal event sequence data (e.g., thousands of event types). DecisionFlow combines a scalable and dynamic temporal event data structure with interactive multi-view visualizations and ad hoc statistical analytics. We provide a detailed review of our methods, and present the results from a 12-person user study. The study results demonstrate that DecisionFlow enables the quick and accurate completion of a range of sequence analysis tasks for datasets containing thousands of event types and millions of individual events.

  1. Flow Visualization of Density in a Cryogenic Wind Tunnel Using Planar Rayleigh and Raman Scattering

    NASA Technical Reports Server (NTRS)

    Herring, Gregory C.; Shirinzadeh, Behrooz

    2002-01-01

    Using a pulsed Nd:YAG laser (532 nm) and a gated, intensified charge-coupled device, planar Rayleigh and Raman scattering techniques have been used to visualize the unseeded Mach 0.2 flow density in a 0.3-meter transonic cryogenic wind tunnel. Detection limits are determined for density measurements by using both unseeded Rayleigh and Raman (N2 vibrational) methods. Seeding with CO2 improved the Rayleigh flow visualization at temperatures below 150 K. The seeded Rayleigh version was used to demonstrate the observation of transient flow features in a separated boundary layer region, which was excited with an oscillatory jet. Finally, a significant degradation of the laser light sheet, in this cryogenic facility, is discussed.

  2. Vector projectile imaging: time-resolved dynamic visualization of complex flow patterns.

    PubMed

    Yiu, Billy Y S; Lai, Simon S M; Yu, Alfred C H

    2014-09-01

    Achieving non-invasive, accurate and time-resolved imaging of vascular flow with spatiotemporal fluctuations is well acknowledged to be an ongoing challenge. In this article, we present a new ultrasound-based framework called vector projectile imaging (VPI) that can dynamically render complex flow patterns over an imaging view at millisecond time resolution. VPI is founded on three principles: (i) high-frame-rate broad-view data acquisition (based on steered plane wave firings); (ii) flow vector estimation derived from multi-angle Doppler analysis (coupled with data regularization and least-squares fitting); (iii) dynamic visualization of color-encoded vector projectiles (with flow speckles displayed as adjunct). Calibration results indicated that by using three transmit angles and three receive angles (-10°, 0°, +10° for both), VPI can consistently compute flow vectors in a multi-vessel phantom with three tubes positioned at different depths (1.5, 4, 6 cm), oriented at different angles (-10°, 0°, +10°) and of different sizes (dilated diameter: 2.2, 4.4 and 6.3 mm; steady flow rate: 2.5 mL/s). The practical merit of VPI was further illustrated through an anthropomorphic flow phantom investigation that considered both healthy and stenosed carotid bifurcation geometries. For the healthy bifurcation with 1.2-Hz carotid flow pulses, VPI was able to render multi-directional and spatiotemporally varying flow patterns (using a nominal frame rate of 416 fps or 2.4-ms time resolution). In the case of stenosed bifurcations (50% eccentric narrowing), VPI enabled dynamic visualization of flow jet and recirculation zones. These findings suggest that VPI holds promise as a new tool for complex flow analysis.

  3. The performance & flow visualization studies of three-dimensional (3-D) wind turbine blade models

    NASA Astrophysics Data System (ADS)

    Sutrisno, Prajitno, Purnomo, W., Setyawan B.

    2016-06-01

    Recently, studies on the design of 3-D wind turbine blades have a less attention even though 3-D blade products are widely sold. In contrary, advanced studies in 3-D helicopter blade tip have been studied rigorously. Studies in wind turbine blade modeling are mostly assumed that blade spanwise sections behave as independent two-dimensional airfoils, implying that there is no exchange of momentum in the spanwise direction. Moreover, flow visualization experiments are infrequently conducted. Therefore, a modeling study of wind turbine blade with visualization experiment is needed to be improved to obtain a better understanding. The purpose of this study is to investigate the performance of 3-D wind turbine blade models with backward-forward swept and verify the flow patterns using flow visualization. In this research, the blade models are constructed based on the twist and chord distributions following Schmitz's formula. Forward and backward swept are added to the rotating blades. Based on this, the additional swept would enhance or diminish outward flow disturbance or stall development propagation on the spanwise blade surfaces to give better blade design. Some combinations, i. e., b lades with backward swept, provide a better 3-D favorable rotational force of the rotor system. The performance of the 3-D wind turbine system model is measured by a torque meter, employing Prony's braking system. Furthermore, the 3-D flow patterns around the rotating blade models are investigated by applying "tuft-visualization technique", to study the appearance of laminar, separated, and boundary layer flow patterns surrounding the 3-dimentional blade system.

  4. Changes in optic nerve head blood flow, visual function, and retinal histology in hypercholesterolemic rabbits.

    PubMed

    Shibata, Maho; Sugiyama, Tetsuya; Hoshiga, Masaaki; Hotchi, Junko; Okuno, Takashi; Oku, Hidehiro; Hanafusa, Toshiaki; Ikeda, Tsunehiko

    2011-12-01

    We investigated the effects of hypercholesterolemia on optic nerve head (ONH) blood flow, visual function, and retinal histology in a rabbit model. Hypercholesterolemia was induced in rabbits by feeding them a high cholesterol (1%) diet for 12 weeks. Changes in blood pressure, intraocular pressure (IOP), and ONH blood flow were monitored at 6 and 12 weeks after treatment. The autoregulation of ONH blood flow as detected by laser speckle flowgraphy was verified by an artificial elevation of IOP at 12 weeks. Visually evoked potentials (VEPs) were also recorded and analyzed at 6 and 12 weeks. Finally, a histological examination as well as immunohistochemistry to endothelial nitric oxide synthase (eNOS) and inducible nitric oxide synthase (iNOS) was performed. In the hypercholesterolemic rabbits, blood pressure, IOP, and ONH blood flow did not alter significantly throughout this study. The autoregulation of ONH blood flow against IOP elevation was found to be impaired at 12 weeks. The amplitudes of the first negative peak of VEPs were diminished. Both the density of the retinal ganglion cells and the thickness of the inner nuclear layer and photoreceptor cell layer were reduced. Immunoreactivity to eNOS was reduced and that to iNOS was enhanced in the hypercholesterolemic rabbits compared to those in the normal control rabbits. The results of this study show that hypercholesterolemia induces impairment in the autoregulation of ONH blood flow and deterioration in visual function and histology. Downregulation of eNOS activity might be one of the causes for impairment of the autoregulation. Enhanced activity of iNOS might be involved in the impaired visual function and histology.

  5. High-throughput pesticide residue quantitative analysis achieved by tandem mass spectrometry with automated flow injection.

    PubMed

    Nanita, Sergio C; Pentz, Anne M; Bramble, Frederick Q

    2009-04-15

    The use of automated flow injection with MS/MS detection for fast quantitation of agrochemicals in food and water samples was demonstrated in this study. Active ingredients from the sulfonylurea herbicide and carbamate insecticide classes were selected as model systems. Samples were prepared using typical procedures from residue methods, placed in an autosampler, and injected directly into a triple quadrupole instrument without chromatographic separation. The technique allows data acquisition in 15 s per injection, with samples being injected every 65 s, representing a significant improvement from the 15-30 min needed in typical HPLC/MS/MS methods. The availability of HPLC systems is an advantage since they can be used in flow-injection mode (bypassing the column compartment). Adequate accuracy, linearity, and precision (R(2) > 0.99 and RSD < 20%) were obtained using external standards prepared in each control matrix. The limit of quantitation (LOQ) achieved for all analytes was 0.01 mg/kg in food samples and 0.1 ng/mL in water; while limits of detection (LOD) were estimated to be about 0.003 mg/kg and 0.03 ng/mL in food and water, respectively. The advantages and limitations of flow injection MS/MS for ultratrace-level quantitative analysis in complex matrixes are discussed.

  6. High-throughput pesticide residue quantitative analysis achieved by tandem mass spectrometry with automated flow injection.

    PubMed

    Nanita, Sergio C; Pentz, Anne M; Bramble, Frederick Q

    2009-04-15

    The use of automated flow injection with MS/MS detection for fast quantitation of agrochemicals in food and water samples was demonstrated in this study. Active ingredients from the sulfonylurea herbicide and carbamate insecticide classes were selected as model systems. Samples were prepared using typical procedures from residue methods, placed in an autosampler, and injected directly into a triple quadrupole instrument without chromatographic separation. The technique allows data acquisition in 15 s per injection, with samples being injected every 65 s, representing a significant improvement from the 15-30 min needed in typical HPLC/MS/MS methods. The availability of HPLC systems is an advantage since they can be used in flow-injection mode (bypassing the column compartment). Adequate accuracy, linearity, and precision (R(2) > 0.99 and RSD < 20%) were obtained using external standards prepared in each control matrix. The limit of quantitation (LOQ) achieved for all analytes was 0.01 mg/kg in food samples and 0.1 ng/mL in water; while limits of detection (LOD) were estimated to be about 0.003 mg/kg and 0.03 ng/mL in food and water, respectively. The advantages and limitations of flow injection MS/MS for ultratrace-level quantitative analysis in complex matrixes are discussed. PMID:19296591

  7. Velocity Vector Field Visualization of Flow in Liquid Acquisition Device Channel

    NASA Technical Reports Server (NTRS)

    McQuillen, John B.; Chao, David F.; Hall, Nancy R.; Zhang, Nengli

    2012-01-01

    A capillary flow liquid acquisition device (LAD) for cryogenic propellants has been developed and tested in NASA Glenn Research Center to meet the requirements of transferring cryogenic liquid propellants from storage tanks to an engine in reduced gravity environments. The prototypical mesh screen channel LAD was fabricated with a mesh screen, covering a rectangular flow channel with a cylindrical outlet tube, and was tested with liquid oxygen (LOX). In order to better understand the performance in various gravity environments and orientations at different liquid submersion depths of the screen channel LAD, a series of computational fluid dynamics (CFD) simulations of LOX flow through the LAD screen channel was undertaken. The resulting velocity vector field visualization for the flow in the channel has been used to reveal the gravity effects on the flow in the screen channel.

  8. Quantitative monitoring of the Chlamydia trachomatis developmental cycle using GFP-expressing bacteria, microscopy and flow cytometry.

    PubMed

    Vromman, François; Laverrière, Marc; Perrinet, Stéphanie; Dufour, Alexandre; Subtil, Agathe

    2014-01-01

    Chlamydiae are obligate intracellular bacteria. These pathogens develop inside host cells through a biphasic cycle alternating between two morphologically distinct forms, the infectious elementary body and the replicative reticulate body. Recently, C. trachomatis strains stably expressing fluorescent proteins were obtained. The fluorochromes are expressed during the intracellular growth of the microbe, allowing bacterial visualization by fluorescence microscopy. Whether they are also present in the infectious form, the elementary body, to a detectable level has not been studied. Here, we show that a C. trachomatis strain transformed with a plasmid expressing the green fluorescent protein (GFP) accumulates sufficient quantities of the probe in elementary bodies for detection by microscopy and flow cytometry. Adhesion of single bacteria was detected. The precise kinetics of bacterial entry were determined by microscopy using automated procedures. We show that during the intracellular replication phase, GFP is a convenient read-out for bacterial growth with several advantages over current methods. In particular, infection rates within a non-homogenous cell population are easily quantified. Finally, in spite of their small size, individual elementary bodies are detected by flow cytometers, allowing for direct enumeration of a bacterial preparation. In conclusion, GFP-expressing chlamydiae are suitable to monitor, in a quantitative manner, progression throughout the developmental cycle. This will facilitate the identification of the developmental steps targeted by anti-chlamydial drugs or host factors.

  9. Flow visualization around a double wedge airfoil model with focusing schlieren system

    NASA Astrophysics Data System (ADS)

    Kashitani, Masashi; Yamaguchi, Yutaka

    2006-03-01

    In the present study, aerodynamic characteristics of the double wedge airfoil model were investigated in a transonic flow by using the shock tube as an intermittent wind tunnel. The driver and driven gases of the shock tube are dry air. The airfoil model of double wedge has the span of 58 mm, chord length c = 75 mm and its maximum thickness is 7.5 mm. The apex of the double wedge airfoil model is located on the 35% chord length from the leading edge. The range of hot gas Mach numbers are from 0.80 to 0.88, and the Reynolds numbers based on chord length are 3.11 × 105 ˜ 3.49 × 105, respectively. The flow visualizations were performed by the sharp focusing schlieren method which can visualize the three dimensional flow fields. The results show that the present system can visualize the transonic flowfield clearer than the previous system, and the shock wave profiles of the center of span in the test section are visualized

  10. The flow of a thin liquid film on a stationary and rotating disk. I - Experimental analysis and flow visualization

    NASA Technical Reports Server (NTRS)

    Thomas, S.; Faghri, A.; Hankey, W.

    1990-01-01

    The mean thickness of a thin liquid film of deionized water with a free surface on a stationary and rotating horizontal disk has been measured with a nonobtrusive capacitance technique. The measurements were taken when the rotational speed was 0-300 RPM and the flow rate was 7.0-15.0 LPM. A flow visualization study of the thin film was also performed to determine the characteristics of the waves on the free surface. When the disk was stationary, a circular hydraulic jump was present on the disk. Surface waves were found in the supercritical and subcritical regions at all flow rates studied. When the rotational speed of the disk is low, a standing wave at the edge of the disk was present. As the rotational speed increased, the surface waves changed from the wavy-laminar region to a region in which the waves ran nearly radially across the disk on top of a thin substrate of fluid.

  11. Visualization and quantitative analysis of lung microstructure using micro CT images

    NASA Astrophysics Data System (ADS)

    Yamamoto, Tetsuo; Kubo, Mitsuru; Kawata, Yoshiki; Niki, Noboru; Matsui, Eisuke; Ohamatsu, Hironobu; Moriyama, Noriyuki

    2004-04-01

    Micro CT system is developed for lung function analysis at a high resolution of the micrometer order (up to 5 μm in spatial resolution). This system reveals the lung distal structures such as interlobular septa, terminal bronchiole, respiratory bronchiole, alveolar duct, and alveolus. In order to visualize lung 3-D microstructures using micro CT images and to analyze them, this research presents a computerized approach. In this approach, the following things are performed: (1) extracting lung distal structures from micro CT images, (2) visualizing extracted lung microstructure in three dimensions, and (3) visualizing inside of lung distal area in three dimensions with fly-through. This approach is applied for to micro CT images of human lung tissue specimens that were obtained by surgical excision and were kept in the state of the inflated fixed lung. And this research succeeded in visualization of lung microstructures using micro CT images to reveal the lung distal structures from bronchiole up to alveolus.

  12. GProX, a user-friendly platform for bioinformatics analysis and visualization of quantitative proteomics data.

    PubMed

    Rigbolt, Kristoffer T G; Vanselow, Jens T; Blagoev, Blagoy

    2011-08-01

    Recent technological advances have made it possible to identify and quantify thousands of proteins in a single proteomics experiment. As a result of these developments, the analysis of data has become the bottleneck of proteomics experiment. To provide the proteomics community with a user-friendly platform for comprehensive analysis, inspection and visualization of quantitative proteomics data we developed the Graphical Proteomics Data Explorer (GProX)(1). The program requires no special bioinformatics training, as all functions of GProX are accessible within its graphical user-friendly interface which will be intuitive to most users. Basic features facilitate the uncomplicated management and organization of large data sets and complex experimental setups as well as the inspection and graphical plotting of quantitative data. These are complemented by readily available high-level analysis options such as database querying, clustering based on abundance ratios, feature enrichment tests for e.g. GO terms and pathway analysis tools. A number of plotting options for visualization of quantitative proteomics data is available and most analysis functions in GProX create customizable high quality graphical displays in both vector and bitmap formats. The generic import requirements allow data originating from essentially all mass spectrometry platforms, quantitation strategies and software to be analyzed in the program. GProX represents a powerful approach to proteomics data analysis providing proteomics experimenters with a toolbox for bioinformatics analysis of quantitative proteomics data. The program is released as open-source and can be freely downloaded from the project webpage at http://gprox.sourceforge.net.

  13. Color surface-flow visualization of fin-generated shock wave boundary-layer interactions

    NASA Technical Reports Server (NTRS)

    Lu, F. K.; Settles, G. S.

    1990-01-01

    Kerosene-lampblack mixtures with addition of a ground colored chalk were used in an experiment on visualizing surface flows of swept shock boundary-layer interactions. The results show that contrasting colors intensify the visualization of different regions of the interaction surface, and help the eye in following the fine streaks to locate the upstream influence. The study confirms observations of the separation occurring at shock strength below accepted values. The superiority of the reported technique over the previous monochrome technique is demonstrated.

  14. Surface flow visualization of separated flows on the forebody of an F-18 aircraft and wind-tunnel model

    NASA Technical Reports Server (NTRS)

    Fisher, David F.; Richwine, David M.; Banks, Daniel W.

    1988-01-01

    A method of in-flight surface flow visualization similar to wind-tunnel-model oil flows is described for cases where photo-chase planes or onboard photography are not practical. This method, used on an F-18 aircraft in flight at high angles of attack, clearly showed surface flow streamlines in the fuselage forebody. Vortex separation and reattachment lines were identified with this method and documented using postflight photography. Surface flow angles measured at the 90 and 270 degrees meridians show excellent agreement with the wind tunnel data for a pointed tangent ogive with an aspect ratio of 3.5. The separation and reattachment line locations were qualitatively similar to the F-18 wind-tunnel-model oil flows but neither the laminar separation bubble nor the boundary-layer transition on the wind tunnel model were evident in the flight surface flows. The separation and reattachment line locations were in fair agreement with the wind tunnel data for the 3.5 ogive. The elliptical forebody shape of the F-18 caused the primary separation lines to move toward the leeward meridian. Little effect of angle of attack on the separation locations was noted for the range reported.

  15. Quantitative myocardial blood flow with Rubidium-82 PET: a clinical perspective.

    PubMed

    Hagemann, Christoffer E; Ghotbi, Adam A; Kjær, Andreas; Hasbak, Philip

    2015-01-01

    Positron emission tomography (PET) allows assessment of myocardial blood flow in absolute terms (ml/min/g). Quantification of myocardial blood flow (MBF) and myocardial flow reserve (MFR) extend the scope of conventional semi-quantitative myocardial perfusion imaging (MPI): e.g. in 1) identification of the extent of a multivessel coronary artery disease (CAD) burden, 2) patients with balanced 3-vessel CAD, 3) patients with subclinical CAD, and 4) patients with regional flow variance, despite of a high global MFR. A more accurate assessment of the ischemic burden in patients with intermediate pretest probability of CAD can support the clinical decision-making in treatment of CAD patients as a complementary tool to the invasive coronary angiography (CAG). Recently, several studies have proven Rubidium-82 ((82)Rb) PET's long-term prognostic value by a significant association between compromised global MFR and major adverse cardiovascular events (MACE), and together with new diagnostic possibilities from measuring the longitudinal myocardial perfusion gradient, cardiac (82)Rb PET faces a promising clinical future. This article reviews current evidence on quantitative (82)Rb PET's ability to diagnose and risk stratify CAD patients, while assessing the potential of the modality in clinical practice. PMID:26550537

  16. Quantitative myocardial blood flow with Rubidium-82 PET: a clinical perspective

    PubMed Central

    Hagemann, Christoffer E; Ghotbi, Adam A; Kjær, Andreas; Hasbak, Philip

    2015-01-01

    Positron emission tomography (PET) allows assessment of myocardial blood flow in absolute terms (ml/min/g). Quantification of myocardial blood flow (MBF) and myocardial flow reserve (MFR) extend the scope of conventional semi-quantitative myocardial perfusion imaging (MPI): e.g. in 1) identification of the extent of a multivessel coronary artery disease (CAD) burden, 2) patients with balanced 3-vessel CAD, 3) patients with subclinical CAD, and 4) patients with regional flow variance, despite of a high global MFR. A more accurate assessment of the ischemic burden in patients with intermediate pretest probability of CAD can support the clinical decision-making in treatment of CAD patients as a complementary tool to the invasive coronary angiography (CAG). Recently, several studies have proven Rubidium-82 (82Rb) PET’s long-term prognostic value by a significant association between compromised global MFR and major adverse cardiovascular events (MACE), and together with new diagnostic possibilities from measuring the longitudinal myocardial perfusion gradient, cardiac 82Rb PET faces a promising clinical future. This article reviews current evidence on quantitative 82Rb PET’s ability to diagnose and risk stratify CAD patients, while assessing the potential of the modality in clinical practice. PMID:26550537

  17. Visualization of vorticity and vortices in wall-bounded turbulent flows.

    PubMed

    Helgeland, Anders; Pettersson Reif, B Anders; Andreassen, Øyvind; Wasberg, Carl Erik

    2007-01-01

    This study was initiated by the scientifically interesting prospect of applying advanced visualization techniques to gain further insight into various spatio-temporal characteristics of turbulent flows. The ability to study complex kinematical and dynamical features of turbulence provides means of extracting the underlying physics of turbulent fluid motion. The objective is to analyze the use of a vorticity field line approach to study numerically generated incompressible turbulent flows. In order to study the vorticity field, we present a field line animation technique which uses a specialized particle advection and seeding strategy. Efficient analysis is achieved by decoupling the rendering stage from the preceding stages of the visualization method. This allows interactive exploration of multiple fields simultaneously, which sets the stage for a more complete analysis of the flow field. Multifield visualizations are obtained using a flexible volume rendering framework which is presented in this paper. Vorticity field lines have been employed as indicators to provide a means to identify "ejection" and "sweep" regions; two particularly important spatio-temporal events in wall-bounded turbulent flows. Their relation to the rate of turbulent kinetic energy production and viscous dissipation, respectively, have been identified. PMID:17622687

  18. Framework and algorithms for illustrative visualizations of time-varying flows on unstructured meshes

    DOE PAGESBeta

    Rattner, Alexander S.; Guillen, Donna Post; Joshi, Alark; Garimella, Srinivas

    2016-03-17

    Photo- and physically realistic techniques are often insufficient for visualization of fluid flow simulations, especially for 3D and time-varying studies. Substantial research effort has been dedicated to the development of non-photorealistic and illustration-inspired visualization techniques for compact and intuitive presentation of such complex datasets. However, a great deal of work has been reproduced in this field, as many research groups have developed specialized visualization software. Additionally, interoperability between illustrative visualization software is limited due to diverse processing and rendering architectures employed in different studies. In this investigation, a framework for illustrative visualization is proposed, and implemented in MarmotViz, a ParaViewmore » plug-in, enabling its use on a variety of computing platforms with various data file formats and mesh geometries. Region-of-interest identification and feature-tracking algorithms incorporated into this tool are described. Implementations of multiple illustrative effect algorithms are also presented to demonstrate the use and flexibility of this framework. Here, by providing an integrated framework for illustrative visualization of CFD data, MarmotViz can serve as a valuable asset for the interpretation of simulations of ever-growing scale.« less

  19. Using falling soap film to visualize flow in a wavy channel

    NASA Astrophysics Data System (ADS)

    Monts, Vontravis; Edokpolo, Osazuwa; Mills, Zachary; Alexeev, Alexander

    2014-11-01

    The disturbances created by the walls of a sinusoidal shaped channel lead to the development of unsteady, time periodic flow. This periodic flow is the result of vortex shedding occurring along the crests of the channel walls. We used a falling soap film to investigate the influence of the channel geometry on the flow. In falling soap films, variations in the thickness of the film correspond to streamlines in the flow. These thickness variations are made visible by reflecting monochromatic light off the film. This allows for soap films to be an accurate, but inexpensive method of visualizing two dimensional flows. In our experiments we used a gravity driven soap film flowing through a wavy channel of several periods and used a high speed camera to record the resulting flow. The collected footage was then analyzed to collect data on the flow. From this data we were able to characterize the dependence of the size of the vortices and their shedding frequency on the amplitude and period of the sinusoidal channel walls as well as the Reynolds number of the flow.

  20. Visualization and measurement of capillary-driven blood flow using spectral domain optical coherence tomography.

    PubMed

    Cito, Salvatore; Ahn, Yeh-Chan; Pallares, Jordi; Duarte, Rodrigo Martinez; Chen, Zhongping; Madou, Marc; Katakis, Ioanis

    2012-09-01

    Capillary-driven flow (CD-flow) in microchannels plays an important role in many microfluidic devices. These devices, the most popular being those based in lateral flow, are becoming increasingly used in health care and diagnostic applications. CD-flow can passively pump biological fluids as blood, serum or plasma, in microchannels and it can enhance the wall mass transfer by exploiting the convective effects of the flow behind the meniscus. The flow behind the meniscus has not been experimentally identified up to now because of the lack of high-resolution, non-invasive, cross-sectional imaging means. In this study, spectral-domain Doppler optical coherence tomography is used to visualize and measure the flow behind the meniscus in CD-flows of water and blood. Microchannels of polydimethylsiloxane and glass with different cross-sections are considered. The predictions of the flow behind the meniscus of numerical simulations using the power-law model for non-Newtonian fluids are in reasonable agreement with the measurements using blood as working fluid. The extension of the Lucas-Washburn equation to non-Newtonian power-law fluids predicts well the velocity of the meniscus of the experiments using blood. PMID:23795150

  1. A quantitative model of ground-water flow during formation of tabular sandstone uranium deposits

    USGS Publications Warehouse

    Sanford, R.F.

    1994-01-01

    Presents a quantitative simulation of regional groundwater flow during uranium deposition in the Westwater Canyon Member and Jackpile Sandstone Member of the Upper Jurassic Morrison Formation in the San Juan basin. Topographic slope, shoreline position, and density contrasts in the lake and pore fluids controlled the directions of flow and recharge-discharge areas. The most important results for uranium ore deposit formation are that regional groundwater discharged throughout the basin, regional discharge was concentrated along the shore line or playa margin, flow was dominantly gravity driven, and compaction dewatering was negligible. A strong association is found between the tabular sandstone uranium deposits and major inferred zones of mixed local and regional groundwater discharge. -from Author

  2. Quantitating and dating recent gene flow between European and East Asian populations.

    PubMed

    Qin, Pengfei; Zhou, Ying; Lou, Haiyi; Lu, Dongsheng; Yang, Xiong; Wang, Yuchen; Jin, Li; Chung, Yeun-Jun; Xu, Shuhua

    2015-04-02

    Historical records indicate that extensive cultural, commercial and technological interaction occurred between European and Asian populations. What have been the biological consequences of these contacts in terms of gene flow? We systematically estimated gene flow between Eurasian groups using genome-wide polymorphisms from 34 populations representing Europeans, East Asians, and Central/South Asians. We identified recent gene flow between Europeans and Asians in most populations we studied, including East Asians and Northwestern Europeans, which are normally considered to be non-admixed populations. In addition we quantitatively estimated the extent of this gene flow using two statistical approaches, and dated admixture events based on admixture linkage disequilibrium. Our results indicate that most genetic admixtures occurred between 2,400 and 310 years ago and show the admixture proportions to be highly correlated with geographic locations, with the highest admixture proportions observed in Central Asia and the lowest in East Asia and Northwestern Europe. Interestingly, we observed a North-to-South decline of European gene flow in East Asians, suggesting a northern path of European gene flow diffusing into East Asian populations. Our findings contribute to an improved understanding of the history of human migration and the evolutionary mechanisms that have shaped the genetic structure of populations in Eurasia.

  3. A quantitative study on accumulation of age mass around stagnation points in nested flow systems

    NASA Astrophysics Data System (ADS)

    Jiang, Xiao-Wei; Wan, Li; Ge, Shemin; Cao, Guo-Liang; Hou, Guang-Cai; Hu, Fu-Sheng; Wang, Xu-Sheng; Li, Hailong; Liang, Si-Hai

    2012-12-01

    The stagnant zones in nested flow systems have been assumed to be critical to accumulation of transported matter, such as metallic ions and hydrocarbons in drainage basins. However, little quantitative research has been devoted to prove this assumption. In this paper, the transport of age mass is used as an example to demonstrate that transported matter could accumulate around stagnation points. The spatial distribution of model age is analyzed in a series of drainage basins of different depths. We found that groundwater age has a local or regional maximum value around each stagnation point, which proves the accumulation of age mass. In basins where local, intermediate and regional flow systems are all well developed, the regional maximum groundwater age occurs at the regional stagnation point below the basin valley. This can be attributed to the long travel distances of regional flow systems as well as stagnancy of the water. However, when local flow systems dominate, the maximum groundwater age in the basin can be located around the local stagnation points due to stagnancy, which are far away from the basin valley. A case study is presented to illustrate groundwater flow and age in the Ordos Plateau, northwestern China. The accumulation of age mass around stagnation points is confirmed by tracer age determined by 14C dating in two boreholes and simulated age near local stagnation points under different dispersivities. The results will help shed light on the relationship between groundwater flow and distributions of groundwater age, hydrochemistry, mineral resources, and hydrocarbons in drainage basins.

  4. Vapor-screen flow-visualization experiments in the NASA Langley 0.3-m transonic cryogenic tunnel

    NASA Technical Reports Server (NTRS)

    Selby, G. V.

    1986-01-01

    The vortical flow on the leeward side of a delta-wing model has been visualized at several different tunnel conditions in the NASA Langley 0.3-Meter Transonic Cryogenic Tunnel using a vapor-screen flow-visualization technique. Vapor-screen photographs of the subject flow field are presented and interpreted relative to phenomenological implications. Results indicate that the use of nitrogen fog in conjunction with the vapor-screen technique is feasibile.

  5. Visual constraints for the perception of quantitative depth from temporal interocular unmatched features.

    PubMed

    Ni, Rui; Chen, Lin; Andersen, George J

    2010-07-21

    Previous research (Brooks & Gillam, 2006) has found that temporal interocular unmatched (IOUM) features generate a perception of subjective contours and can result in a perception of quantitative depth. In the present study we examine in detail the factors important for quantitative depth perception from IOUM features. In Experiments 1 and 2 observers were shown temporal IOUM features based on three dots that disappeared behind an implicit surface. Subjects reported a perception of a subjective surface and were able to perceive qualitative depth. In Experiments 3 and 4 metrical depth was perceived when binocular disparity features were added to the display. These results suggest that quantitative depth from IOUM information is perceived when binocular matched information is present in regions adjacent to the surface. In addition, the perceived depth of the subjective surface decreased with an increase in the width of the subjective surface suggesting a limitation in the propagation of quantitative depth to surface regions where qualitative depth information is available.

  6. Visual eyes: a quantitative analysis of the photoreceptor layer in deep-sea sharks.

    PubMed

    Newman, Amy S; Marshall, Justin N; Collin, Shaun P

    2013-01-01

    The marine environment presents unique visual challenges for a range of organisms, particularly those dwelling at great depths, where sunlight may either be absent or drop to very low levels. Under these environmental conditions, the visual system must maximise light absorption in order to enhance the detection of prey, predators and potential mates. Using stereological analysis of retinal wholemounts, the distribution and number of photoreceptors (rods) was determined for 5 deep-sea shark species from a range of depths (46-1,500 m). All species possessed areas of increased photoreceptor density (with peaks between 41,000 and 82,000 rods/mm(2)) within discrete regions of the retina. The total number of rods in the photoreceptor layer also varied between 17 × 10(6) and 63 × 10(6). It is evident that increasing sensitivity of the retina is an important adaptation to life in the deep sea. The location of discrete areas of high cell density within the photoreceptor layer of the retina corresponds to discrete areas of the visual field that are sampled at a higher intensity, hence increasing sensitivity. The location of these areas of increased sensitivity differed between the species of this study. The disparity of areas of increased sensitivity seen between species is thought to reflect distinctive predator avoidance and prey capture strategies. This study reveals that the visual demands of deep-sea sharks vary interspecifically and that sampling of each species' visual field is not solely determined by its habitat. PMID:24280649

  7. High speed optical tomography system for quantitative measurement and visualization of dynamic features in a round jet

    NASA Astrophysics Data System (ADS)

    McMackin, L.; Hugo, R. J.; Bishop, K. P.; Chen, E. Y.; Pierson, R. E.; Truman, C. R.

    An optical tomography system that is capable of operating at frame rates of up to 5 kHz has been used to obtain spatially resolved cross-sectional temperature images of a heated round jet. These tomographic images show dynamic details in the evolving vortical flow structures found in the near field of the jet that are consistent with previous studies of low speed jet flow. Reconstructions produced by the system are quantitative temperature distributions of a planar cross section of the jet measuring temperature differences with a spatial resolution of 1.4 mm.

  8. High-speed visualization of disturbed pathlines in axial flow ventricular assist device under pulsatile conditions

    PubMed Central

    Yang, Fang; Kormos, Robert L.; Antaki, James F.

    2015-01-01

    Objective: To investigate potentially pro-thrombotic flow patterns within an axial flow ventricular assist device under clinically relevant pulsatile hemodynamic conditions. Methods A transparent replica of the HeartMate-II was visualized using a high speed camera at both low and high frame rates (125 and 3000 fps). Three steady-state conditions were studied: nominal (4.5 lpm), low flow (3.0 lpm) and high flow (6.0 lpm). Time-varying conditions were introduced with external pulsatile pump which modulated the flow rate by approximately +/−50% of the mean, corresponding to a pulsatility index of 1.0. Results At nominal and high flow rates, the path lines within the upstream region were generally stable, well attached, and streamlined. As the flow rate was reduced below 3.8 lpm, a rapid transition to a chaotic velocity field occurred exhibiting a large toroidal vortex adjacent to the upstream bearing. The pathlines in the downstream stator section were consistently chaotic for all hemodynamic conditions investigated. It was common to observe tracer particles trapped within recirculation bubbles and drawn retrograde, causing repeated contact with the bearing surfaces. The addition of pulsatility caused the flow field to become periodically chaotic during the diastolic portion of the cardiac cycle depending on the instantaneous flow rate and acceleration. Conclusion The contribution of pulsatility by the native heart may induce a periodic disturbance to an otherwise stable flow field within an axial flow VAD, particularly during the diastolic and decelerating portion of the cardiac cycle. Potentially pro-thrombotic flow features were found to occur periodically in the region of the upstream bearing. PMID:26208892

  9. Performing Quantitative Imaging Acquisition, Analysis and Visualization Using the Best of Open Source and Commercial Software Solutions

    PubMed Central

    Shenoy, Shailesh M.

    2016-01-01

    A challenge in any imaging laboratory, especially one that uses modern techniques, is to achieve a sustainable and productive balance between using open source and commercial software to perform quantitative image acquisition, analysis and visualization. In addition to considering the expense of software licensing, one must consider factors such as the quality and usefulness of the software’s support, training and documentation. Also, one must consider the reproducibility with which multiple people generate results using the same software to perform the same analysis, how one may distribute their methods to the community using the software and the potential for achieving automation to improve productivity. PMID:27516727

  10. Hypersonic Nozzle/Afterbody Experiment: Flow Visualization and Boundary Layer Experiments

    NASA Technical Reports Server (NTRS)

    Keener, Earl R.; Spaid, Frank W.; Arnold, James O. (Technical Monitor)

    1994-01-01

    This study was conducted to experimentally characterize the flow field created by the interaction of a single-expansion-ramp-nozzle (SERN) flow with a hypersonic external stream Data were obtained from a generic nozzle/afterbody model in the 3.5-Foot Hypersonic Wind Tunnel of the NASA Ames Research Center in a cooperative experimental program involving Ames and the McDonnell Douglas Aerospace. The model design and test planning were performed in close cooperation with members of the Ames computational fluid dynamics (CFD) team for the National Aero-Space Plane (NASP) program. This paper presents experimental results consisting of oil-flow and shadowgraph flow-visualization photographs, afterbody surface-pressure distributions, boundary-layer rake measurements, and Preston-tube skin-friction measurements.

  11. A three-dimensional visualization technique applied to flow around a delta wing

    NASA Astrophysics Data System (ADS)

    Yoda, M.; Hesselink, L.

    1990-12-01

    The visualization of flows in two dimensions by using planer laser light sheets is extended to three dimensions by rapidly scanning the laser light sheet to obtain a set of 'slices' of the flow around a full-span delta wing. The leading edge vortices, which are marked with smoke, are unburst by tangential blowing around the leading edges at angles of attack in excess of 25 deg. Since the measurement period is on the order of the smallest convection time scale, a virtually instantaneous set of planar cross sections of the flow is obtained. Software is used to stack the slices and recontruct a three-dimensional surface of the smoke-seeded fluid. This surface, which corresponds to the vortices, clearly shows the qualitative effects of blowing on the delta wing flow.

  12. FlowSOM: Using self-organizing maps for visualization and interpretation of cytometry data.

    PubMed

    Van Gassen, Sofie; Callebaut, Britt; Van Helden, Mary J; Lambrecht, Bart N; Demeester, Piet; Dhaene, Tom; Saeys, Yvan

    2015-07-01

    The number of markers measured in both flow and mass cytometry keeps increasing steadily. Although this provides a wealth of information, it becomes infeasible to analyze these datasets manually. When using 2D scatter plots, the number of possible plots increases exponentially with the number of markers and therefore, relevant information that is present in the data might be missed. In this article, we introduce a new visualization technique, called FlowSOM, which analyzes Flow or mass cytometry data using a Self-Organizing Map. Using a two-level clustering and star charts, our algorithm helps to obtain a clear overview of how all markers are behaving on all cells, and to detect subsets that might be missed otherwise. R code is available at https://github.com/SofieVG/FlowSOM and will be made available at Bioconductor. PMID:25573116

  13. Flow visualization studies of VTOL aircraft models during Hover in ground effect

    NASA Technical Reports Server (NTRS)

    Mourtos, Nikos J.; Couillaud, Stephane; Carter, Dale; Hange, Craig; Wardwell, Doug; Margason, Richard J.

    1995-01-01

    A flow visualization study of several configurations of a jet-powered vertical takeoff and landing (VTOL) aircraft model during hover in ground effect was conducted. A surface oil flow technique was used to observe the flow patterns on the lower surfaces of the model. There were significant configuration effects. Wing height with respect to fuselage, the presence of an engine inlet duct beside the fuselage, and nozzle pressure ratio are seen to have strong effects on the surface flow angles on the lower surface of the wing. This test was part of a program to improve the methods for predicting the hot gas ingestion (HGI) for jet-powered vertical/short takeoff and landing (V/STOL) aircraft. The tests were performed at the Jet Calibration and Hover Test (JCAHT) Facility at Ames Research Center.

  14. A siphonage flow and thread-based low-cost platform enables quantitative and sensitive assays.

    PubMed

    Lu, Fang; Mao, Qingqing; Wu, Rui; Zhang, Shenghai; Du, Jianxiu; Lv, Jiagen

    2015-01-21

    For pump-free, material abundant, portable, and easy-to-operate low-cost microfluidics, a siphonage flow microfluidic thread-based analytical device (S-μTAD) platform enabling quantitative and sensitive assays was designed. Renewable and continuous siphonage flow allowed replicate sampling and detection on one channel/device, obviating some possible inconsistencies among channels or devices. Y-shaped channels were fabricated with polyester cotton blend thread, due to its greater chemiluminescent sensitivity in comparison with that of cotton and polyester threads. S-μTAD sensors for glucose and uric acid were fabricated by using oxidase-immobilized cotton thread as the sample arm of the channels. The acceptable reproducibility and high sensitivity, demonstrated by the relative standard deviations of less than 5% in all cases and the detection limits of 4 × 10(-8) mol L(-1) for hydrogen peroxide, 1 × 10(-7) mol L(-1) for glucose, and 3 × 10(-6) mol L(-1) for uric acid, demonstrated the feasibility of the S-μTAD for quantitative assays. Good agreements between S-μTAD/sensor results and hospital results for blood glucose and uric acid assays indicated the capability of S-μTAD/sensors for the analysis of real samples. These findings proved the utility of siphonage for low-cost microfluidics and the suitability of our S-μTAD design for quantitative assays.

  15. Background-oriented schlieren: Techniques and applications for multi-scale flow visualization and measurement

    NASA Astrophysics Data System (ADS)

    Hargather, Michael; Settles, Gary

    2008-11-01

    Background oriented schlieren (BOS) is a new and versatile technique for imaging refractive fluid flows. This simplistic and low-cost flow visualization technique can be applied over a range of geometric scales, from typical laboratory setups to large outdoor experiments. The basic principles underlying BOS are briefly reviewed, including: background selection, sensitivity estimation, optimal geometric arrangement of optics, and analysis techniques. The influence of optical depth-of-field and geometric placement of the test specimen are also explored. Laboratory-scale applications and results include supersonic wind tunnel and candle-plume visualizations. The technique is also expanded to include ``natural-background-oriented schlieren,'' wherein naturally-occurring pseudo-random backgrounds such as trees and a cornfield are used to image outdoor explosions, gunshots, and thermal plumes. A wide range of potential backgrounds and applications is considered.

  16. Quantitative passive soil vapor sampling for VOCs--Part 4: Flow-through cell.

    PubMed

    McAlary, Todd; Groenevelt, Hester; Seethapathy, Suresh; Sacco, Paolo; Crump, Derrick; Tuday, Michael; Schumacher, Brian; Hayes, Heidi; Johnson, Paul; Parker, Louise; Górecki, Tadeusz

    2014-05-01

    This paper presents a controlled experiment comparing several quantitative passive samplers for monitoring concentrations of volatile organic compound (VOC) vapors in soil gas using a flow-through cell. This application is simpler than conventional active sampling using adsorptive tubes because the flow rate does not need to be precisely measured and controlled, which is advantageous because the permeability of subsurface materials affects the flow rate and the permeability of geologic materials is highly variable. Using passive samplers in a flow-through cell, the flow rate may not need to be known exactly, as long as it is sufficient to purge the cell in a reasonable time and minimize any negative bias attributable to the starvation effect. An experiment was performed in a 500 mL flow-through cell using a two-factor, one-half fraction fractional factorial test design with flow rates of 80, 670 and 930 mL min(-1) and sample durations of 10, 15 and 20 minutes for each of five different passive samplers (passive Automatic Thermal Desorption Tube, Radiello®, SKC Ultra, Waterloo Membrane Sampler™ and 3M™ OVM 3500). A Summa canister was collected coincident with each passive sampler and analyzed by EPA Method TO-15 to provide a baseline for comparison of the passive sampler concentrations. The passive sampler concentrations were within a factor of 2 of the Summa canister concentrations in 32 of 35 cases. Passive samples collected at the low flow rate and short duration showed low concentrations, which is likely attributable to insufficient purging of the cell after sampler placement.

  17. Background Oriented Schlieren (BOS) and other Flow Visualization Developments and Applications at GRC

    NASA Technical Reports Server (NTRS)

    Clem, Michelle; Woike, Mark

    2013-01-01

    This is a presentation to be given at an internal NASA Advanced Schlieren Working Group Meeting. The presentation will cover the recent developments and applications of flow visualization methods at GRC. The topics being discussed will include the use of Background Oriented Schlieren (BOS) in the study of screech and its associated shock spacing as well as in the investigation of broadband shock noise reduction in the Jet-Surface Interaction Tests. In addition, other flow visualiztion methods will be discussed in an on-going study comparing schlieren, shadowgraph, BOS, and focusing schlieren.

  18. Combined single-pulse holography and time-resolved laser schlieren for flow visualization

    NASA Technical Reports Server (NTRS)

    Burner, A. W.; Goad, W. K.

    1981-01-01

    A pulsed ruby laser and continuous-wave argon ion laser were used in a combined setup at the Langley Expansion Tube for single pulse holography and time resolved laser schlieren with a common optical axis. The systems can be operated simultaneously for a single run. For a single frame, the pulsed holographic setup offers the options of shadowgraph, Schlieren, and interferometry from the reconstructed hologram as well as the advantage of post-run sensitivity adjustments. For flow establishment studies the time resolved laser Schlieren provides visualization of the flow field every 12.5 microns for up to 80 frames with an exposure time per frame of 5.4 microns.

  19. Virtual reality aided visualization of fluid flow simulations with application in medical education and diagnostics.

    PubMed

    Djukic, Tijana; Mandic, Vesna; Filipovic, Nenad

    2013-12-01

    Medical education, training and preoperative diagnostics can be drastically improved with advanced technologies, such as virtual reality. The method proposed in this paper enables medical doctors and students to visualize and manipulate three-dimensional models created from CT or MRI scans, and also to analyze the results of fluid flow simulations. Simulation of fluid flow using the finite element method is performed, in order to compute the shear stress on the artery walls. The simulation of motion through the artery is also enabled. The virtual reality system proposed here could shorten the length of training programs and make the education process more effective. PMID:24290920

  20. A water tunnel flow visualization study of the vortex flow structures on the F/A-18 aircraft

    NASA Technical Reports Server (NTRS)

    Sandlin, Doral R.; Ramirez, Edgar J.

    1991-01-01

    The vortex flow structures occurring on the F/A-18 aircraft at high angles of attack were studied. A water tunnel was used to gather flow visualization data on the forebody vortex and the wing leading edge extension vortex. The longitudinal location of breakdown of the leading edge vortex was found to be consistently dependent on the angle of attack. Other parameters such as Reynolds number, model scale, and model fidelity had little influence on the overall behavior of the flow structures studied. The lateral location of the forebody vortex system was greatly influenced by changes in the angle of sideslip. Strong interactions can occur between the leading edge extension vortex and the forebody vortex. Close attention was paid to vortex induced flows on various airframe components of the F/A-18. Reynolds number and angle of attack greatly affected the swirling intensity, and therefore the strength of the studied vortices. Water tunnel results on the F/A-18 correlated well with those obtained in similar studies at both full and sub scale levels. The water tunnel can provide, under certain conditions, good simulations of realistic flows in full scale configurations.

  1. Efficient computation and visualization of coherent structures in fluid flow applications.

    PubMed

    Garth, Christoph; Gerhardt, Florian; Tricoche, Xavier; Hans, Hagen

    2007-01-01

    The recently introduced notion of Finite-Time Lyapunov Exponent to characterize Coherent Lagrangian Structures provides a powerful framework for the visualization and analysis of complex technical flows. Its definition is simple and intuitive, and it has a deep theoretical foundation. While the application of this approach seems straightforward in theory, the associated computational cost is essentially prohibitive. Due to the Lagrangian nature of this technique, a huge number of particle paths must be computed to fill the space-time flow domain. In this paper, we propose a novel scheme for the adaptive computation of FTLE fields in two and three dimensions that significantly reduces the number of required particle paths. Furthermore, for three-dimensional flows, we show on several examples that meaningful results can be obtained by restricting the analysis to a well-chosen plane intersecting the flow domain. Finally, we examine some of the visualization aspects of FTLE-based methods and introduce several new variations that help in the analysis of specific aspects of a flow.

  2. ReactionFlow: an interactive visualization tool for causality analysis in biological pathways

    PubMed Central

    2015-01-01

    Background Molecular and systems biologists are tasked with the comprehension and analysis of incredibly complex networks of biochemical interactions, called pathways, that occur within a cell. Through interviews with domain experts, we identified four common tasks that require an understanding of the causality within pathways, that is, the downstream and upstream relationships between proteins and biochemical reactions, including: visualizing downstream consequences of perturbing a protein; finding the shortest path between two proteins; detecting feedback loops within the pathway; and identifying common downstream elements from two or more proteins. Results We introduce ReactionFlow, a visual analytics application for pathway analysis that emphasizes the structural and causal relationships amongst proteins, complexes, and biochemical reactions within a given pathway. To support the identified causality analysis tasks, user interactions allow an analyst to filter, cluster, and select pathway components across linked views. Animation is used to highlight the flow of activity through a pathway. Conclusions We evaluated ReactionFlow by providing our application to two domain experts who have significant experience with biomolecular pathways, after which we conducted a series of in-depth interviews focused on each of the four causality analysis tasks. Their feedback leads us to believe that our techniques could be useful to researchers who must be able to understand and analyze the complex nature of biological pathways. ReactionFlow is available at https://github.com/CreativeCodingLab/ReactionFlow. PMID:26361502

  3. A high-speed photographic system for flow visualization in a steam turbine

    NASA Technical Reports Server (NTRS)

    Barna, G. J.

    1973-01-01

    A photographic system was designed to visualize the moisture flow in a steam turbine. Good performance of the system was verified using dry turbine mockups in which an aerosol spray simulated, in a rough way, the moisture flow in the turbine. Borescopes and fiber-optic light tubes were selected as the general instrumentation approach. High speed motion-picture photographs of the liquid flow over the stator blade surfaces were taken using stroboscopic lighting. Good visualization of the liquid flow was obtained. Still photographs of drops in flight were made using short duration flash sources. Drops with diameters as small as 30 micrometers (0.0012 in.) could be resolved. In addition, motion pictures of a spray of water simulating the spray off the rotor blades and shrouds were taken at normal framing rates. Specially constructed light tubes containing small tungsten-halogen lamps were used. Sixteen millimeter photography was used in all cases. Two potential problems resulting from the two-phase turbine flow (attenuation and scattering of light by the fog present and liquid accumulation on the borescope mirrors) were taken into account in the photographic system design but not evaluated experimentally.

  4. Water Tunnel Flow Visualization Study Through Poststall of 12 Novel Planform Shapes

    NASA Technical Reports Server (NTRS)

    Gatlin, Gregory M.; Neuhart, Dan H.

    1996-01-01

    To determine the flow field characteristics of 12 planform geometries, a flow visualization investigation was conducted in the Langley 16- by 24-Inch Water Tunnel. Concepts studied included flat plate representations of diamond wings, twin bodies, double wings, cutout wing configurations, and serrated forebodies. The off-surface flow patterns were identified by injecting colored dyes from the model surface into the free-stream flow. These dyes generally were injected so that the localized vortical flow patterns were visualized. Photographs were obtained for angles of attack ranging from 10' to 50', and all investigations were conducted at a test section speed of 0.25 ft per sec. Results from the investigation indicate that the formation of strong vortices on highly swept forebodies can improve poststall lift characteristics; however, the asymmetric bursting of these vortices could produce substantial control problems. A wing cutout was found to significantly alter the position of the forebody vortex on the wing by shifting the vortex inboard. Serrated forebodies were found to effectively generate multiple vortices over the configuration. Vortices from 65' swept forebody serrations tended to roll together, while vortices from 40' swept serrations were more effective in generating additional lift caused by their more independent nature.

  5. Fluorescence Visualization of Hypersonic Flow Past Triangular and Rectangular Boundary-layer Trips

    NASA Technical Reports Server (NTRS)

    Danehy, Paul M.; Garcia, A. P.; Borg, Stephen E.; Dyakonov, Artem A.; Berry, Scott A.; Inman, Jennifer A.; Alderfer, David W.

    2007-01-01

    Planar laser-induced fluorescence (PLIF) flow visualization has been used to investigate the hypersonic flow of air over surface protrusions that are sized to force laminar-to-turbulent boundary layer transition. These trips were selected to simulate protruding Space Shuttle Orbiter heat shield gap-filler material. Experiments were performed in the NASA Langley Research Center 31-Inch Mach 10 Air Wind Tunnel, which is an electrically-heated, blowdown facility. Two-mm high by 8-mm wide triangular and rectangular trips were attached to a flat plate and were oriented at an angle of 45 degrees with respect to the oncoming flow. Upstream of these trips, nitric oxide (NO) was seeded into the boundary layer. PLIF visualization of this NO allowed observation of both laminar and turbulent boundary layer flow downstream of the trips for varying flow conditions as the flat plate angle of attack was varied. By varying the angle of attack, the Mach number above the boundary layer was varied between 4.2 and 9.8, according to analytical oblique-shock calculations. Computational Fluid Dynamics (CFD) simulations of the flowfield with a laminar boundary layer were also performed to better understand the flow environment. The PLIF images of the tripped boundary layer flow were compared to a case with no trip for which the flow remained laminar over the entire angle-of-attack range studied. Qualitative agreement is found between the present observed transition measurements and a previous experimental roughness-induced transition database determined by other means, which is used by the shuttle return-to-flight program.

  6. Visual processing of optic flow and motor control in the human posterior cingulate sulcus.

    PubMed

    Field, David T; Inman, Laura A; Li, Li

    2015-10-01

    Previous studies have shown that the human posterior cingulate contains a visual processing area selective for optic flow (CSv). However, other studies performed in both humans and monkeys have identified a somatotopic motor region at the same location (CMA). Taken together, these findings suggested the possibility that the posterior cingulate contains a single visuomotor integration region. To test this idea we used fMRI to identify both visual and motor areas of the posterior cingulate in the same brains and to test the activity of those regions during a visuomotor task. Results indicated that rather than a single visuomotor region the posterior cingulate contains adjacent but separate motor and visual regions. CSv lies in the fundus of the cingulate sulcus, while CMA lies in the dorsal bank of the sulcus, slightly superior in terms of stereotaxic coordinates. A surprising and novel finding was that activity in CSv was suppressed during the visuomotor task, despite the visual stimulus being identical to that used to localize the region. This may provide an important clue to the specific role played by this region in the utilization of optic flow to control self-motion.

  7. Flow visualization around cylinders in a channel flow using particle image velocimetry

    SciTech Connect

    Martinez, R.; Philip, O.G.; Schmidl, W.D.; Hassan, Y.A. )

    1993-01-01

    One of the major concerns with steam generator operation is the tube vibration caused by turbulent flow buffeting. The vibration can cause wear on the tube joints, which may eventually lead to ruptures and leaks. When the cumulative leaks result in a major loss of fluid, the plant needs to be shut down, and the leaking tubes must be either plugged or removed. This repair procedure can be very costly. To help avoid this problem, experimental tests need to be performed to test the empirical correlations that predict the behavior of the turbulent flow around the tubes. In this experiment, the particle image velocimetry (PIV) experimental measurement technique was used to capture the flow velocity field around a cylindrical tube.

  8. A rapid technique for measuring and visualizing the extent of separated flow

    NASA Astrophysics Data System (ADS)

    Ostowari, C.

    1984-06-01

    A method is described for rapidly measuring and visualizing the extent of separated flow suitable for a wind tunnel environment. The method utilizes a continuously swinging total pressure probe. This technique permits acquiring and presenting graphical records of separated regions in a fraction of the time required by other methods. Typical results indicate the presence of highly complicated three-dimensional separated regions for a typical general aviation twin-engine aircraft at post-stall conditions.

  9. Visualizing flow fields using acoustic Doppler current profilers and the Velocity Mapping Toolbox

    USGS Publications Warehouse

    Jackson, P. Ryan

    2013-01-01

    The purpose of this fact sheet is to provide examples of how the U.S. Geological Survey is using acoustic Doppler current profilers for much more than routine discharge measurements. These instruments are capable of mapping complex three-dimensional flow fields within rivers, lakes, and estuaries. Using the Velocity Mapping Toolbox to process the ADCP data allows detailed visualization of the data, providing valuable information for a range of studies and applications.

  10. Neurofilament protein defines regional patterns of cortical organization in the macaque monkey visual system: a quantitative immunohistochemical analysis

    NASA Technical Reports Server (NTRS)

    Hof, P. R.; Morrison, J. H.; Bloom, F. E. (Principal Investigator)

    1995-01-01

    Visual function in monkeys is subserved at the cortical level by a large number of areas defined by their specific physiological properties and connectivity patterns. For most of these cortical fields, a precise index of their degree of anatomical specialization has not yet been defined, although many regional patterns have been described using Nissl or myelin stains. In the present study, an attempt has been made to elucidate the regional characteristics, and to varying degrees boundaries, of several visual cortical areas in the macaque monkey using an antibody to neurofilament protein (SMI32). This antibody labels a subset of pyramidal neurons with highly specific regional and laminar distribution patterns in the cerebral cortex. Based on the staining patterns and regional quantitative analysis, as many as 28 cortical fields were reliably identified. Each field had a homogeneous distribution of labeled neurons, except area V1, where increases in layer IVB cell and in Meynert cell counts paralleled the increase in the degree of eccentricity in the visual field representation. Within the occipitotemporal pathway, areas V3 and V4 and fields in the inferior temporal cortex were characterized by a distinct population of neurofilament-rich neurons in layers II-IIIa, whereas areas located in the parietal cortex and part of the occipitoparietal pathway had a consistent population of large labeled neurons in layer Va. The mediotemporal areas MT and MST displayed a distinct population of densely labeled neurons in layer VI. Quantitative analysis of the laminar distribution of the labeled neurons demonstrated that the visual cortical areas could be grouped in four hierarchical levels based on the ratio of neuron counts between infragranular and supragranular layers, with the first (areas V1, V2, V3, and V3A) and third (temporal and parietal regions) levels characterized by low ratios and the second (areas MT, MST, and V4) and fourth (frontal regions) levels characterized by

  11. Quantitatively Measuring In situ Flows using a Self-Contained Underwater Velocimetry Apparatus (SCUVA)

    PubMed Central

    Katija, Kakani; Colin, Sean P.; Costello, John H.; Dabiri, John O.

    2011-01-01

    The ability to directly measure velocity fields in a fluid environment is necessary to provide empirical data for studies in fields as diverse as oceanography, ecology, biology, and fluid mechanics. Field measurements introduce practical challenges such as environmental conditions, animal availability, and the need for field-compatible measurement techniques. To avoid these challenges, scientists typically use controlled laboratory environments to study animal-fluid interactions. However, it is reasonable to question whether one can extrapolate natural behavior (i.e., that which occurs in the field) from laboratory measurements. Therefore, in situ quantitative flow measurements are needed to accurately describe animal swimming in their natural environment. We designed a self-contained, portable device that operates independent of any connection to the surface, and can provide quantitative measurements of the flow field surrounding an animal. This apparatus, a self-contained underwater velocimetry apparatus (SCUVA), can be operated by a single scuba diver in depths up to 40 m. Due to the added complexity inherent of field conditions, additional considerations and preparation are required when compared to laboratory measurements. These considerations include, but are not limited to, operator motion, predicting position of swimming targets, available natural suspended particulate, and orientation of SCUVA relative to the flow of interest. The following protocol is intended to address these common field challenges and to maximize measurement success. PMID:22064442

  12. Flow visualization of mast-mounted-sight/main rotor aerodynamic interactions

    NASA Technical Reports Server (NTRS)

    Ghee, Terence A.; Kelley, Henry L.

    1993-01-01

    Flow visualization tests were conducted on a 27 percent-scale AH-64 attack helicopter model fitted with various mast-mounted-sight configurations in an attempt to identify the cause of adverse vibration encountered during full-scale flight tests of an Apache/Longbow configuration. The tests were conducted at the NASA Langley Research Center in the 14- by 22-Foot Subsonic Tunnel. A symmetric and an asymmetric mast-mounted-sight oriented at several skew angles were tested at forward and rearward flight speeds of 30 and 45 knots. A laser light sheet seeded with vaporized propylene glycol was used to visualize the wake of the sight in planes parallel and perpendicular to the freestream flow. Analysis of the flow visualization data identified the frequency of the wake shed from the sight, the angle-of-attack at the sight, and the location where the sight wake crossed the rotor plane. Differences in wake structure were observed between the various sight configurations and slew angles. Postulations into the cause of the adverse vibration found in flight test are given along with considerations for future tests.

  13. Flow visualization V; Proceedings of the 5th International Symposium, Prague, Czechoslovakia, Aug. 21-25, 1989

    SciTech Connect

    Reznicek, R.

    1990-01-01

    The present conference on flow visualization encompasses methods exploiting tracing particles, surface tracing methods, methods exploiting the effects of streaming fluid on passing radiation/field, computer-aided flow visualization, and applications to fluid mechanics, aerodynamics, flow devices, shock tubes, and heat/mass transfer. Specific issues include visualizing velocity distribution by stereo photography, dark-field Fourier quasiinterferometry, speckle tomography of an open flame, a fast eye for real-time image analysis, and velocity-field determination based on flow-image analysis. Also addressed are flows around rectangular prisms with oscillating flaps at the leading edges, the tomography of aerodynamic objects, the vapor-screen technique applied to a delta-wing aircraft, flash-lamp planar imaging, IR-thermography applications in convective heat transfer, and the visualization of marangoni effects in evaporating sessile drops.

  14. VISUALLY OBSERVED MOLD AND MOLDY ODOR VERSUS QUANTITATIVELY MEASURED MICROBIAL EXPOSURE IN HOMES

    EPA Science Inventory

    The main study objective was to compare different methods for assessing mold exposure in conjunction with an epidemiologic study on the development of children's asthma. Homes of 184 children were assessed for mold by visual observations and dust sampling at child's age 1 (Year ...

  15. Verification of the time evolution of cosmological simulations via hypothesis-driven comparative and quantitative visualization

    SciTech Connect

    Hsu, Chung-hsing; Ahrens, James P; Heitmann, Katrin

    2009-01-01

    We describe a visualization assisted process for the verification of cosmological simulation codes. The need for code verification stems from the requirement for very accurate predictions in order to interpret observational data confidently. We compare different simulation algorithms in order to reliably predict differences in simulation results and understand their dependence on input parameter settings.

  16. Non-Invasive Visualization and Quantitation of Cardiovascular Structure and Function.

    ERIC Educational Resources Information Center

    Ritman, E. L.; And Others

    1979-01-01

    Described is a new approach to investigative physiology based on computerized transaxial tomography, in which visualization and measurement of the internal structure of the cardiopulmonary system is possible without postmortem, biopsy, or vivisection procedures. Examples are given for application of the Dynamic Spatial Reconstructor (DSR). (CS)

  17. Review of Measurement Instruments and Procedures for Assessing Visual Behaviors: Implications for Quantitative Measurement.

    ERIC Educational Resources Information Center

    Janssen, Cynthia M.

    The assessment of vision as it relates to and interacts with motor development is reviewed. The focus is on eye readiness skills normally occuring in infants' first few months of life and preceding eye-hand coordination. These visual skills fall into three categories: fixation, tracking, and scanning. Six standardized scales are reviewed and…

  18. Quantitative measurement by artificial vision of small bubbles in flowing mercury

    SciTech Connect

    Paquit, Vincent C; Wendel, Mark W; Felde, David K; Riemer, Bernie

    2011-01-01

    At the Spallation Neutron Source (SNS), an accelerator-based neutron source located at the Oak Ridge National Laboratory (Tennessee, USA), the production of neutrons is obtained by accelerating protons against a mercury target. This self-cooling target, however, suffers rapid heat deposition by the beam pulse leading to large pressure changes and thus to cavitations that may be damaging to the container. In order to locally compensate for pressure increases, a small-bubble population is added to the mercury flow using gas bubblers. The geometry of the bubblers being unknown, we are testing several bubblers configurations and are using machine vision techniques to characterize their efficiency by quantitative measurement of the created bubble population. In this paper we thoroughly detail the experimental setup and the image processing techniques used to quantitatively assess the bubble population. To support this approach we are comparing our preliminary results for different bubblers and operating modes, and discuss potential improvements.

  19. Pore level visualization of foam flow in a silicon micromodel. SUPRI TR 100

    SciTech Connect

    Woody, F.; Blunt, M.; Castanier, L.

    1996-01-01

    This paper is concerned with the behavior of foam in porous media at the pore level. Identical, heterogeneous silicon micromodels, two dimensionally etched to replicate flow in Berea Sandstone, were used. The models, already saturated with varying concentrations of surfactant and, at times, oil were invaded with air. Visual observations were made of these air displacement events in an effort to determine foam flow characteristics with varying surfactant concentrations, and differing surfactants in the presence of oil. These displacement events were recorded on video tape. These tapes are available at the Stanford University Petroleum Research Institute, Stanford, California. The observed air flow characteristics can be broadly classified into two: continuous and discontinuous. Continuous air flow was observed in two phase runs when the micromodel contained no aqueous surfactant solution. Air followed a tortuous path to the outlet, splitting and reconnecting around grains, isolating water located in dead-end or circumvented pores, all without breaking and forming bubbles. No foam was created. Discontinuous air flow occurred in runs containing surfactant - with smaller bubble sizes appearing with higher surfactant concentrations. Air moved through the medium by way of modified bubble train flow where bubbles travel through pore throats and tend to reside more statically in larger pore bodies until enough force is applied to move them along. The lamellae were stable, and breaking and reforming events by liquid drainage and corner flow were observed in higher surfactant concentrations. However, the classic snap-off process, as described by Roof (1973) was not seen at all.

  20. Simulation experiments on two-phase natural circulation in a freon-113 flow visualization loop

    SciTech Connect

    Lee, Sang Yong; Ishii, Mamoru

    1988-01-01

    In order to study the two-phase natural circulaton and flow termination during a small break loss of coolant accident in LWR, simulation experiments have been performed using a Freon-113 flow visualization loop. The main focus of the present experiment was placed on the two-phase flow behavior in the hot-leg U-bend typical of B and W LWR systems. The loop was built based on the two-phase flow scaling criteria developed under this program to find out the effect of fluid properties, phase changes and coupling between hydrodynamic and heat transfer phenomena. Significantly different flow behaviors have been observed due to the non-equilibrium phase change phenomena such as the flashing and condensation on the Freon loop in comparison with the previous adiabatic experiment. The phenomena created much more unstable hydrodynamic conditions which lead to cyclic or oscillatory flow behaviors. Also, the void distribution and primary loop flow rate were measured in detail in addition to the important key paramaters, such as the power input, loop friction and the liquid level inside the simulated steam generator.

  1. The effect of visualizing the flow of multimedia content among and inside devices.

    PubMed

    Lee, Dong-Seok

    2009-05-01

    This study introduces a user interface, referred to as the flow interface, which provides a graphical representation of the movement of content among and inside audio/video devices. The proposed interface provides a different frame of reference with content-oriented visualization of the generation, manipulation, storage, and display of content as well as input and output. The flow interface was applied to a VCR/DVD recorder combo, one of the most complicated consumer products. A between-group experiment was performed to determine whether the flow interface helps users to perform various tasks and to examine the learning effect of the flow interface, particularly in regard to hooking up and recording tasks. The results showed that participants with access to the flow interface performed better in terms of success rate and elapsed time. In addition, the participants indicated that they could easily understand the flow interface. The potential of the flow interface for application to other audio video devices, and design issues requiring further consideration, are discussed. PMID:19027891

  2. Flow pattern visualization in a mimic anaerobic digester: experimental and computational studies.

    PubMed

    Vesvikar, M S; Varma, R; Karim, K; Al-Dahhan, M

    2005-01-01

    Advanced non-invasive experiments like computer automated radioactive particle tracking and computed tomography along with computational fluid dynamics (CFD) simulations were performed in mimic anaerobic digesters to visualize their flow pattern and obtain hydrodynamic parameters. The mixing in the digester was provided by sparging gas at three different flow rates. The simulation results in terms of overall flow pattern, location of circulation cells and stagnant regions, trends of liquid velocity profiles, and volume of dead zones agree reasonably well with the experimental data. CFD simulations were also performed on different digester configurations. The effects of changing draft tube size, clearance, and shape of the tank bottoms were calculated to evaluate the effect of digester design on its flow pattern. Changing the draft tube clearance and height had no influence on the flow pattern or dead regions volume. However increasing the draft tube diameter or incorporating a conical bottom design helped in reducing the volume of the dead zones as compared to a flat bottom digester. The simulations showed that the gas flow rate sparged by a single point (0.5 cm diameter) sparger does not have appreciable effect on the flow pattern of the digesters. PMID:16180475

  3. Visualization of Secondary Flow Development in High Aspect Ratio Channels with Curvature

    NASA Technical Reports Server (NTRS)

    Meyer, Michael L.; Giuliani, James E.

    1994-01-01

    The results of an experimental project to visually examine the secondary flow structure that develops in curved, high aspect-ratio rectangular channels are presented. The results provide insight into the fluid dynamics within high aspect ratio channels. A water flow test rig constructed out of plexiglass, with an adjustable aspect ratio, was used for these experiments. Results were obtained for a channel geometry with a hydraulic diameter of 10.6 mm (0.417 in.), an aspect ratio of 5.0, and a hydraulic radius to curvature radius ratio of 0.0417. Flow conditions were varied to achieve Reynolds numbers up to 5,100. A new particle imaging velocimetry technique was developed which could resolve velocity information from particles entering and leaving the field of view. Time averaged secondary flow velocity vectors, obtained using this velocimetry technique, are presented for 30 degrees, 60 degrees, and 90 degrees into a 180 degrees bend and at a Reynolds number of 5,100. The secondary flow results suggest the coexistence of both the classical curvature induced vortex pair flow structure and the eddies seen in straight turbulent channel flow.

  4. A Study to Formulate Quantitative Guidelines for the Audio-Visual Communications Field. Final Report.

    ERIC Educational Resources Information Center

    Faris, Gene; Sherman, Mendel

    Quantitative guidelines for use in determining the audiovisual (AV) needs of educational institutions were developed by the Octobe r 14-16, 1965 Seminar of the NDEA (National Defense Education Act), Faris-Sherman study. The guidelines that emerged were based in part on a review of past efforts and existing standards but primarily reflected the…

  5. Visualization techniques to experimentally model flow and heat transfer in turbine and aircraft flow passages

    NASA Technical Reports Server (NTRS)

    Russell, Louis M.; Hippensteele, Steven A.

    1991-01-01

    Increased attention to fuel economy and increased thrust requirements have increased the demand for higher aircraft gas turbine engine efficiency through the use of higher turbine inlet temperatures. These higher temperatures increase the importance of understanding the heat transfer patterns which occur throughout the turbine passages. It is often necessary to use a special coating or some form of cooling to maintain metal temperatures at a level which the metal can withstand for long periods of time. Effective cooling schemes can result in significant fuel savings through higher allowable turbine inlet temperatures and can increase engine life. Before proceeding with the development of any new turbine it is economically desirable to create both mathematical and experimental models to study and predict flow characteristics and temperature distributions. Some of the methods are described used to physically model heat transfer patterns, cooling schemes, and other complex flow patterns associated with turbine and aircraft passages.

  6. Investigation and visualization of internal flow through particle aggregates and microbial flocs using particle image velocimetry.

    PubMed

    Xiao, Feng; Lam, Kit Ming; Li, Xiao-yan

    2013-05-01

    An advanced particle-tracking and flow-visualization technology, particle image velocimetry (PIV), was utilized to investigate the hydrodynamic properties of large aggregates in water. The laser-based PIV system was used together with a settling column to capture the streamlines around two types of aggregates: latex particle aggregates and activated sludge (AS) flocs. Both types of the aggregates were highly porous and fractal with fractal dimensions of 2.13±0.31 for the latex particle aggregates (1210-2144 μm) and 1.78±0.24 for the AS flocs (1265-3737 μm). The results show that PIV is a powerful flow visualization technique capable of determining flow field details at the micrometer scale around and through settling aggregates and flocs. The PIV streamlines provided direct experimental proof of internal flow through the aggregate interiors. According to the PIV images, fluid collection efficiency ranged from 0.052 to 0.174 for the latex particle aggregates and from 0.008 to 0.126 for AS flocs. AS flocs are apparently less permeable than the particle aggregates, probably due to the extracellular polymeric substances (EPSs) produced by bacteria clogging the pores within the flocs. The internal permeation of fractal aggregates and bio-flocs would enhance flocculation between particles and material transport into the aggregates.

  7. Retrobulbar blood flow and visual field alterations after acute ethanol ingestion

    PubMed Central

    Weber, Anke; Remky, Andreas; Bienert, Marion; der Velden, Klaudia Huber-van; Kirschkamp, Thomas; Rennings, Corinna; Roessler, Gernot; Plange, Niklas

    2013-01-01

    Background The purpose of this study was to test the effect of ethyl alcohol on the koniocellular and magnocellular pathway of visual function and to investigate the relationship between such visual field changes and retrobulbar blood flow in healthy subjects. Methods In 12 healthy subjects (mean age 32 ± 4 years), color Doppler imaging, short-wavelength automated perimetry, and frequency doubling perimetry was performed before and 60 minutes after oral intake of 80 mL of 40 vol% ethanol. Mean and pattern standard deviations for short-wavelength automated and frequency doubling perimetry were assessed. End diastolic velocity (EDV) and peak systolic velocity (PSV) were measured in the central retinal and ophthalmic arteries using color Doppler imaging. Systemic blood pressure, heart rate, intraocular pressure, and blood alcohol concentration were determined. Results Mean PSV and EDV in the central retinal artery showed a significant increase after alcohol intake (P = 0.03 and P = 0.02, respectively). Similarly, we found a significant acceleration of blood flow velocity in the ophthalmic artery (P = 0.02 for PSV; P = 0.04 for EDV). Mean intraocular pressure decreased by 1.0 mmHg after alcohol ingestion (P = 0.01). Retinal sensitivity in short-wavelength automated perimetry did not alter, whereas in frequency doubling perimetry, the mean deviation decreased significantly. Systolic and diastolic blood pressure did not change significantly. Mean blood alcohol concentration was 0.38 ± 0.16 g/L. Conclusion Although ethanol is known to cause peripheral vasodilation, our subjects had no significant drop in systemic blood pressure. However, a significant increase of blood flow velocity was seen in the retrobulbar vessels. Regarding visual function, moderate alcohol consumption led to reduced performance in the magnocellular visual system tested by frequency doubling perimetry, but had no effect on short-wavelength automated perimetry. PMID:23990703

  8. Quantitative Evaluation of Stereo Visual Odometry for Autonomous Vessel Localisation in Inland Waterway Sensing Applications.

    PubMed

    Kriechbaumer, Thomas; Blackburn, Kim; Breckon, Toby P; Hamilton, Oliver; Casado, Monica Rivas

    2015-01-01

    Autonomous survey vessels can increase the efficiency and availability of wide-area river environment surveying as a tool for environment protection and conservation. A key challenge is the accurate localisation of the vessel, where bank-side vegetation or urban settlement preclude the conventional use of line-of-sight global navigation satellite systems (GNSS). In this paper, we evaluate unaided visual odometry, via an on-board stereo camera rig attached to the survey vessel, as a novel, low-cost localisation strategy. Feature-based and appearance-based visual odometry algorithms are implemented on a six degrees of freedom platform operating under guided motion, but stochastic variation in yaw, pitch and roll. Evaluation is based on a 663 m-long trajectory (>15,000 image frames) and statistical error analysis against ground truth position from a target tracking tachymeter integrating electronic distance and angular measurements. The position error of the feature-based technique (mean of ±0.067 m) is three times smaller than that of the appearance-based algorithm. From multi-variable statistical regression, we are able to attribute this error to the depth of tracked features from the camera in the scene and variations in platform yaw. Our findings inform effective strategies to enhance stereo visual localisation for the specific application of river monitoring. PMID:26694411

  9. Quantitative Evaluation of Stereo Visual Odometry for Autonomous Vessel Localisation in Inland Waterway Sensing Applications

    PubMed Central

    Kriechbaumer, Thomas; Blackburn, Kim; Breckon, Toby P.; Hamilton, Oliver; Rivas Casado, Monica

    2015-01-01

    Autonomous survey vessels can increase the efficiency and availability of wide-area river environment surveying as a tool for environment protection and conservation. A key challenge is the accurate localisation of the vessel, where bank-side vegetation or urban settlement preclude the conventional use of line-of-sight global navigation satellite systems (GNSS). In this paper, we evaluate unaided visual odometry, via an on-board stereo camera rig attached to the survey vessel, as a novel, low-cost localisation strategy. Feature-based and appearance-based visual odometry algorithms are implemented on a six degrees of freedom platform operating under guided motion, but stochastic variation in yaw, pitch and roll. Evaluation is based on a 663 m-long trajectory (>15,000 image frames) and statistical error analysis against ground truth position from a target tracking tachymeter integrating electronic distance and angular measurements. The position error of the feature-based technique (mean of ±0.067 m) is three times smaller than that of the appearance-based algorithm. From multi-variable statistical regression, we are able to attribute this error to the depth of tracked features from the camera in the scene and variations in platform yaw. Our findings inform effective strategies to enhance stereo visual localisation for the specific application of river monitoring. PMID:26694411

  10. Quantitative Evaluation of Stereo Visual Odometry for Autonomous Vessel Localisation in Inland Waterway Sensing Applications.

    PubMed

    Kriechbaumer, Thomas; Blackburn, Kim; Breckon, Toby P; Hamilton, Oliver; Casado, Monica Rivas

    2015-12-17

    Autonomous survey vessels can increase the efficiency and availability of wide-area river environment surveying as a tool for environment protection and conservation. A key challenge is the accurate localisation of the vessel, where bank-side vegetation or urban settlement preclude the conventional use of line-of-sight global navigation satellite systems (GNSS). In this paper, we evaluate unaided visual odometry, via an on-board stereo camera rig attached to the survey vessel, as a novel, low-cost localisation strategy. Feature-based and appearance-based visual odometry algorithms are implemented on a six degrees of freedom platform operating under guided motion, but stochastic variation in yaw, pitch and roll. Evaluation is based on a 663 m-long trajectory (>15,000 image frames) and statistical error analysis against ground truth position from a target tracking tachymeter integrating electronic distance and angular measurements. The position error of the feature-based technique (mean of ±0.067 m) is three times smaller than that of the appearance-based algorithm. From multi-variable statistical regression, we are able to attribute this error to the depth of tracked features from the camera in the scene and variations in platform yaw. Our findings inform effective strategies to enhance stereo visual localisation for the specific application of river monitoring.

  11. Fabrication, Operation and Flow Visualization in Surface-acoustic-wave-driven Acoustic-counterflow Microfluidics

    PubMed Central

    Travagliati, Marco; Shilton, Richie; Beltram, Fabio; Cecchini, Marco

    2013-01-01

    Surface acoustic waves (SAWs) can be used to drive liquids in portable microfluidic chips via the acoustic counterflow phenomenon. In this video we present the fabrication protocol for a multilayered SAW acoustic counterflow device. The device is fabricated starting from a lithium niobate (LN) substrate onto which two interdigital transducers (IDTs) and appropriate markers are patterned. A polydimethylsiloxane (PDMS) channel cast on an SU8 master mold is finally bonded on the patterned substrate. Following the fabrication procedure, we show the techniques that allow the characterization and operation of the acoustic counterflow device in order to pump fluids through the PDMS channel grid. We finally present the procedure to visualize liquid flow in the channels. The protocol is used to show on-chip fluid pumping under different flow regimes such as laminar flow and more complicated dynamics characterized by vortices and particle accumulation domains. PMID:24022515

  12. Advanced Supersonic Nozzle Concepts: Experimental Flow Visualization Results Paired With LES

    NASA Astrophysics Data System (ADS)

    Berry, Matthew; Magstadt, Andrew; Stack, Cory; Gaitonde, Datta; Glauser, Mark; Syracuse University Team; The Ohio State University Team

    2015-11-01

    Advanced supersonic nozzle concepts are currently under investigation, utilizing multiple bypass streams and airframe integration to bolster performance and efficiency. This work focuses on the parametric study of a supersonic, multi-stream jet with aft deck. The single plane of symmetry, rectangular nozzle, displays very complex and unique flow characteristics. Flow visualization techniques in the form of PIV and schlieren capture flow features at various deck lengths and Mach numbers. LES is compared to the experimental results to both validate the computational model and identify limitations of the simulation. By comparing experimental results to LES, this study will help create a foundation of knowledge for advanced nozzle designs in future aircraft. SBIR Phase II with Spectral Energies, LLC under direction of Barry Kiel.

  13. In-vivo visualization of melanoma tumor microvessels and blood flow velocity changes accompanying tumor growth

    NASA Astrophysics Data System (ADS)

    Ishida, Hiroki; Hachiga, Tadashi; Andoh, Tsugunobu; Akiguchi, Shunsuke

    2012-11-01

    We demonstrate that using micro multipoint laser Doppler velocimetry (μ-MLDV) for noninvasive in-vivo imaging of blood vessels is useful for diagnosing malignant melanomas by comparison with visual diagnosis by dermoscopy. The blood flow velocity in microvessels varied during growth of melanomas transplanted in mouse ears. Mouse ears were observed by μ-MLDV up to 16 days after transplantation. The blood flow velocity in the tumor increased with increasing time and reached maximum of 4.5 mm/s at 9 days, which is more than twice that prior to transplantation. After 12 days, when the lesion had grown to an area of 6.6 mm2, we observed the formation of new blood vessels in the tumor. Finally, when the lesion had an area of 18 mm2 after 16 days, the flow velocity in the tumor decreased to approximately 3.2 mm/s.

  14. Strategies for Effectively Visualizing a 3D Flow Using Volume Line Integral Convolution

    NASA Technical Reports Server (NTRS)

    Interrante, Victoria; Grosch, Chester

    1997-01-01

    This paper discusses strategies for effectively portraying 3D flow using volume line integral convolution. Issues include defining an appropriate input texture, clarifying the distinct identities and relative depths of the advected texture elements, and selectively highlighting regions of interest in both the input and output volumes. Apart from offering insights into the greater potential of 3D LIC as a method for effectively representing flow in a volume, a principal contribution of this work is the suggestion of a technique for generating and rendering 3D visibility-impeding 'halos' that can help to intuitively indicate the presence of depth discontinuities between contiguous elements in a projection and thereby clarify the 3D spatial organization of elements in the flow. The proposed techniques are applied to the visualization of a hot, supersonic, laminar jet exiting into a colder, subsonic coflow.

  15. msIQuant--Quantitation Software for Mass Spectrometry Imaging Enabling Fast Access, Visualization, and Analysis of Large Data Sets.

    PubMed

    Källback, Patrik; Nilsson, Anna; Shariatgorji, Mohammadreza; Andrén, Per E

    2016-04-19

    This paper presents msIQuant, a novel instrument- and manufacturer-independent quantitative mass spectrometry imaging software suite that uses the standardized open access data format imzML. Its data processing structure enables rapid image display and the analysis of very large data sets (>50 GB) without any data reduction. In addition, msIQuant provides many tools for image visualization including multiple interpolation methods, low intensity transparency display, and image fusion. It also has a quantitation function that automatically generates calibration standard curves from series of standards that can be used to determine the concentrations of specific analytes. Regions-of-interest in a tissue section can be analyzed based on a number of quantities including the number of pixels, average intensity, standard deviation of intensity, and median and quartile intensities. Moreover, the suite's export functions enable simplified postprocessing of data and report creation. We demonstrate its potential through several applications including the quantitation of small molecules such as drugs and neurotransmitters. The msIQuant suite is a powerful tool for accessing and evaluating very large data sets, quantifying drugs and endogenous compounds in tissue areas of interest, and for processing mass spectra and images.

  16. Quantitative, In Situ Visualization of Metal-Ion Dissolution and Transport Using (1) H Magnetic Resonance Imaging.

    PubMed

    Bray, Joshua M; Davenport, Alison J; Ryder, Karl S; Britton, Melanie M

    2016-08-01

    Quantitative mapping of metal ions freely diffusing in solution is important across a diverse range of disciplines and is particularly significant for dissolution processes in batteries, metal corrosion, and electroplating/polishing of manufactured components. However, most current techniques are invasive, requiring sample extraction, insertion of an electrode, application of an electric potential or the inclusion of a molecular sensor. Thus, there is a need for techniques to visualize the distribution of metal ions non-invasively, in situ, quantitatively, in three dimensions (3D) and in real time. Here we have used (1) H magnetic resonance imaging (MRI) to make quantitative 3D maps showing evolution of the distribution of Cu(2+) ions, not directly visible by MRI, during the electrodissolution of copper, with high sensitivity and spatial resolution. The images are sensitive to the speciation of copper, the depletion of dissolved O2 in the electrolyte and show the dissolution of Cu(2+) ions is not uniform across the anode. PMID:27329307

  17. Visualization analysis of tiger-striped flow mark generation phenomena in injection molding

    NASA Astrophysics Data System (ADS)

    Owada, Shigeru; Yokoi, Hidetoshi

    2016-03-01

    The generation mechanism of tiger-striped flow marks of polypropylene (PP)/rubber/talc blends in injection molding was investigated by dynamic visualization analysis in a glass-inserted mold. The analysis revealed that the behavior of the melt flow front correlates with the flow mark generation. The cloudy part in the tiger-striped flow marks corresponded to the low transcription rate area of the melt diverging near the cavity wall, while the glossy part corresponded to the high transcription rate area of the melt converging toward the cavity wall side. The melt temperature at the high transcription rate area was slightly lower than that at the low transcription rate area. These phenomena resulted due to the difference in the temperature of the melt front that was caused by the asymmetric fountain flow. These results suggest the followings; At the moment when the melt is broken near the one side of cavity wall due to piling the extensional strains up to a certain level, the melt spurts out near the broken side. It results in generating asymmetric fountain flow temporarily to relax the extensional front surface, which moves toward the opposite side to form the high transcription area.

  18. Use of laser flow visualization techniques in reactor component thermal-hydraulic studies

    SciTech Connect

    Oras, J.J.; Kasza, K.E.

    1984-01-01

    To properly design reactor components, an understanding of the various thermal hydraulic phenomena, i.e., thermal stratification flow channeling, recirculation regions, shear layers, etc., is necessary. In the liquid metal breeder reactor program, water is commonly used to replace sodium in experimental testing to facilitate the investigations, (i.e., reduce cost and allow fluid velocity measurement or flow pattern study). After water testing, limited sodium tests can be conducted to validate the extrapolation of the water results to sodium. This paper describes a novel laser flow visualization technique being utilized at ANL together with various examples of its use and plans for further development. A 3-watt argon-ion laser, in conjunction with a cylindrical opticallens, has been used to create a thin (approx. 1-mm) intense plane of laser light for the illuminiation of various flow tracers in precisely defined regions of interest within a test article having windows. Both fluorescing dyes tuned to the wavelength of the laser light (to maximize brightness and sharpness of flow image) and small (< 0.038-mm, 0.0015-in. dia.) opaque, nearly neutrally buoyant polystyrene spheres (to ensure that the particles trace out the fluid motion) have been used as flow tracers.

  19. Flow Visualization of a von Kármán Ogive Forebody with Plasma Actuation

    NASA Astrophysics Data System (ADS)

    Farnsworth, John; Francis, Zachary; Witt, Reid; Porter, Chris; McLaughlin, Thomas

    2012-11-01

    The flow field around an axisymmetric forebody at a moderate angle of attack can produce a significant side force, and thus a yawing moment, on the body. The side force results from an asymmetric vortex state and therefore pressure distribution that forms on the body. This asymmetric vortex state originates from a convective instability in the flow field, meaning that minor geometric or flow disturbances near the apex of the model can perturb the flow into an asymmetric state. In the current experiments two single dielectric barrier discharge plasma actuators are used to perturb the flow and control the vortex state. Smoke flow visualization techniques were utilized to better understand the behavior of the vortices under plasma actuation. It was found that the vortex state responds proportionally to the voltage of the plasma actuation. Additionally, the response of the vortex state to control changed drastically with changes in Reynolds number, suggesting a relation between the blowing ratio and the behavior of the vortex state.

  20. The development of quantum dot calibration beads and quantitative multicolor bioassays in flow cytometry and microscopy.

    PubMed

    Wu, Yang; Campos, Samuel K; Lopez, Gabriel P; Ozbun, Michelle A; Sklar, Larry A; Buranda, Tione

    2007-05-15

    The use of fluorescence calibration beads has been the hallmark of quantitative flow cytometry. It has enabled the direct comparison of interlaboratory data as well as quality control in clinical flow cytometry. In this article, we describe a simple method for producing color-generalizable calibration beads based on streptavidin functionalized quantum dots. Based on their broad absorption spectra and relatively narrow emission, which is tunable on the basis of dot size, quantum dot calibration beads can be made for any fluorophore that matches their emission color. In an earlier publication, we characterized the spectroscopic properties of commercial streptavidin functionalized dots (Invitrogen). Here we describe the molecular assembly of these dots on biotinylated beads. The law of mass action is used to readily define the site densities of the dots on the beads. The applicability of these beads is tested against the industry standard, namely commercial fluorescein calibration beads. The utility of the calibration beads is also extended to the characterization surface densities of dot-labeled epidermal growth factor ligands as well as quantitative indicators of the binding of dot-labeled virus particles to cells.

  1. Quantitative measurements of cerebral blood flow in volume imaging PET scanners

    SciTech Connect

    Smith, R.J.; Shao, L.; Freifelder, R.; Karp, J.S.; Ragland, J.D.

    1995-08-01

    Quantitative measurements of Cerebral Blood Flow (CBF) are performed in a volume imaging PET Scanner by means of moderate activity infusions. In equilibrium infusions, activations are measured by scanning over 10 minutes with 16 minute activations. Typical measured whole brain CBF values are 37{+-}8 ml/min/100g, close to the value of 42 ml/min/100g reported by other groups using this method. For ramped infusions, scanning over 4 minutes with 5 minute activations results in whole brain CBFs of 49 {+-} 9 ml/min/100g, close to the Kety and Schmidt value of 50 ml/min/100g. Both equilibrium and ramped infusion methods have been used to study face and word memory in human subjects. Both methods were able to detect significant activations in regions implicated in human memory. The authors conclude that precise quantitation of regional CBF is achieved using both methods, and that ramped infusions also provide accurate measures of CBF. In addition a simplified protocol for ramped infusion studies has been developed. In this method the whole brain tissue time activity curve generated from dynamic scanning is replaced by an appropriately scaled camera coincidence countrate curve. The resulting whole brain CBF values are only 7% different from the dynamic scan and fit results. Regional CBFs (rCBF) may then be generated from the summed image (4.25 minutes) using a count density vs flow lookup table.

  2. A bead-based method for multiplexed identification and quantitation of DNA sequences using flow cytometry.

    PubMed

    Spiro, A; Lowe, M; Brown, D

    2000-10-01

    A new multiplexed, bead-based method which utilizes nucleic acid hybridizations on the surface of microscopic polystyrene spheres to identify specific sequences in heterogeneous mixtures of DNA sequences is described. The method consists of three elements: beads (5.6-microm diameter) with oligomer capture probes attached to the surface, three fluorophores for multiplexed detection, and flow cytometry instrumentation. Two fluorophores are impregnated within each bead in varying amounts to create different bead types, each associated with a unique probe. The third fluorophore is a reporter. Following capture of fluorescent cDNA sequences from environmental samples, the beads are analyzed by flow cytometric techniques which yield a signal intensity for each capture probe proportional to the amount of target sequences in the analyte. In this study, a direct hybrid capture assay was developed and evaluated with regard to sequence discrimination and quantitation of abundances. The target sequences (628 to 728 bp in length) were obtained from the 16S/23S intergenic spacer region of microorganisms collected from polluted groundwater at the nuclear waste site in Hanford, Wash. A fluorescence standard consisting of beads with a known number of fluorescent DNA molecules on the surface was developed, and the resolution, sensitivity, and lower detection limit for measuring abundances were determined. The results were compared with those of a DNA microarray using the same sequences. The bead method exhibited far superior sequence discrimination and possesses features which facilitate accurate quantitation. PMID:11010868

  3. A bead-based method for multiplexed identification and quantitation of DNA sequences using flow cytometry.

    PubMed

    Spiro, A; Lowe, M; Brown, D

    2000-10-01

    A new multiplexed, bead-based method which utilizes nucleic acid hybridizations on the surface of microscopic polystyrene spheres to identify specific sequences in heterogeneous mixtures of DNA sequences is described. The method consists of three elements: beads (5.6-microm diameter) with oligomer capture probes attached to the surface, three fluorophores for multiplexed detection, and flow cytometry instrumentation. Two fluorophores are impregnated within each bead in varying amounts to create different bead types, each associated with a unique probe. The third fluorophore is a reporter. Following capture of fluorescent cDNA sequences from environmental samples, the beads are analyzed by flow cytometric techniques which yield a signal intensity for each capture probe proportional to the amount of target sequences in the analyte. In this study, a direct hybrid capture assay was developed and evaluated with regard to sequence discrimination and quantitation of abundances. The target sequences (628 to 728 bp in length) were obtained from the 16S/23S intergenic spacer region of microorganisms collected from polluted groundwater at the nuclear waste site in Hanford, Wash. A fluorescence standard consisting of beads with a known number of fluorescent DNA molecules on the surface was developed, and the resolution, sensitivity, and lower detection limit for measuring abundances were determined. The results were compared with those of a DNA microarray using the same sequences. The bead method exhibited far superior sequence discrimination and possesses features which facilitate accurate quantitation.

  4. Assessment of blood flow velocity and pulsatility in cerebral perforating arteries with 7-T quantitative flow MRI.

    PubMed

    Bouvy, W H; Geurts, L J; Kuijf, H J; Luijten, P R; Kappelle, L J; Biessels, G J; Zwanenburg, J J M

    2016-09-01

    Thus far, blood flow velocity measurements with MRI have only been feasible in large cerebral blood vessels. High-field-strength MRI may now permit velocity measurements in much smaller arteries. The aim of this proof of principle study was to measure the blood flow velocity and pulsatility of cerebral perforating arteries with 7-T MRI. A two-dimensional (2D), single-slice quantitative flow (Qflow) sequence was used to measure blood flow velocities during the cardiac cycle in perforating arteries in the basal ganglia (BG) and semioval centre (CSO), from which a mean normalised pulsatility index (PI) per region was calculated (n = 6 human subjects, aged 23-29 years). The precision of the measurements was determined by repeated imaging and performance of a Bland-Altman analysis, and confounding effects of partial volume and noise on the measurements were simulated. The median number of arteries included was 14 in CSO and 19 in BG. In CSO, the average velocity per volunteer was in the range 0.5-1.0 cm/s and PI was 0.24-0.39. In BG, the average velocity was in the range 3.9-5.1 cm/s and PI was 0.51-0.62. Between repeated scans, the precision of the average, maximum and minimum velocity per vessel decreased with the size of the arteries, and was relatively low in CSO and BG compared with the M1 segment of the middle cerebral artery. The precision of PI per region was comparable with that of M1. The simulations proved that velocities can be measured in vessels with a diameter of more than 80 µm, but are underestimated as a result of partial volume effects, whilst pulsatility is overestimated. Blood flow velocity and pulsatility in cerebral perforating arteries have been measured directly in vivo for the first time, with moderate to good precision. This may be an interesting metric for the study of haemodynamic changes in aging and cerebral small vessel disease. © 2015 The Authors NMR in Biomedicine Published by John Wiley & Sons Ltd.

  5. Emerging flow injection mass spectrometry methods for high-throughput quantitative analysis.

    PubMed

    Nanita, Sergio C; Kaldon, Laura G

    2016-01-01

    Where does flow injection analysis mass spectrometry (FIA-MS) stand relative to ambient mass spectrometry (MS) and chromatography-MS? Improvements in FIA-MS methods have resulted in fast-expanding uses of this technique. Key advantages of FIA-MS over chromatography-MS are fast analysis (typical run time <60 s) and method simplicity, and FIA-MS offers high-throughput without compromising sensitivity, precision and accuracy as much as ambient MS techniques. Consequently, FIA-MS is increasingly becoming recognized as a suitable technique for applications where quantitative screening of chemicals needs to be performed rapidly and reliably. The FIA-MS methods discussed herein have demonstrated quantitation of diverse analytes, including pharmaceuticals, pesticides, environmental contaminants, and endogenous compounds, at levels ranging from parts-per-billion (ppb) to parts-per-million (ppm) in very complex matrices (such as blood, urine, and a variety of foods of plant and animal origin), allowing successful applications of the technique in clinical diagnostics, metabolomics, environmental sciences, toxicology, and detection of adulterated/counterfeited goods. The recent boom in applications of FIA-MS for high-throughput quantitative analysis has been driven in part by (1) the continuous improvements in sensitivity and selectivity of MS instrumentation, (2) the introduction of novel sample preparation procedures compatible with standalone mass spectrometric analysis such as salting out assisted liquid-liquid extraction (SALLE) with volatile solutes and NH4(+) QuEChERS, and (3) the need to improve efficiency of laboratories to satisfy increasing analytical demand while lowering operational cost. The advantages and drawbacks of quantitative analysis by FIA-MS are discussed in comparison to chromatography-MS and ambient MS (e.g., DESI, LAESI, DART). Generally, FIA-MS sits 'in the middle' between ambient MS and chromatography-MS, offering a balance between analytical

  6. Visualizing request-flow comparison to aid performance diagnosis in distributed systems.

    PubMed

    Sambasivan, Raja R; Shafer, Ilari; Mazurek, Michelle L; Ganger, Gregory R

    2013-12-01

    Distributed systems are complex to develop and administer, and performance problem diagnosis is particularly challenging. When performance degrades, the problem might be in any of the system's many components or could be a result of poor interactions among them. Recent research efforts have created tools that automatically localize the problem to a small number of potential culprits, but research is needed to understand what visualization techniques work best for helping distributed systems developers understand and explore their results. This paper compares the relative merits of three well-known visualization approaches (side-by-side, diff, and animation) in the context of presenting the results of one proven automated localization technique called request-flow comparison. Via a 26-person user study, which included real distributed systems developers, we identify the unique benefits that each approach provides for different problem types and usage modes. PMID:24051813

  7. Implementation of visual data mining for unsteady blood flow field in an aortic aneurysm.

    PubMed

    Morizawa, Seiichiro; Shimoyama, Koji; Obayashi, Shigeru; Funamoto, Kenichi; Hayase, Toshiyuki

    2011-12-01

    This study was performed to determine the relations between the features of wall shear stress and aneurysm rupture. For this purpose, visual data mining was performed in unsteady blood flow simulation data for an aortic aneurysm. The time-series data of wall shear stress given at each grid point were converted to spatial and temporal indices, and the grid points were sorted using a self-organizing map based on the similarity of these indices. Next, the results of cluster analysis were mapped onto the real space of the aortic aneurysm to specify the regions that may lead to aneurysm rupture. With reference to previous reports regarding aneurysm rupture, the visual data mining suggested specific hemodynamic features that cause aneurysm rupture. GRAPHICAL ABSTRACT:

  8. Matching visual and nonvisual signals: evidence for a mechanism to discount optic flow during locomotion

    NASA Astrophysics Data System (ADS)

    Thurrell, Adrian; Pelah, Adar

    2005-03-01

    We report on recent experiments to investigate the Arthrovisual Locomotor Effect (ALE), a mechanism based on non-visual signals postulated to discount or remove the self-generated visual motion signals during locomotion. It is shown that perceptual matches made by standing subjects to a constant motion optic flow stimulus that is viewed while walking on a treadmill are linearly reduced by walking speed, a measure of the reported ALE. The degree of reduction in perceived speed depends on the similarity of the motor activity to natural locomotion, thus for the four activities tested, ALE strength is ranked as follows: Walking > Cycling > Hand Pedalling > Finger Tapping = 0. Other variations and important controls for the ALE are described.

  9. Visualization of topological landscape in shear-flow dynamics of amorphous solids

    NASA Astrophysics Data System (ADS)

    Fujita, Takeshi; Ohara, Koji; Miura, Keiji; Hirata, Akihiko; Kotani, Motoko; Nishiura, Yasumasa; Chen, Mingwei

    2015-05-01

    A potential energy landscape (PEL) gives rise to diverse non-equilibrium dynamics in complex systems. In this study, we visualize the topological landscape of a steady-state flow under shear deformation in a model metallic glass. We use the “state space network” as the best predictor of state transitions in terms of statistical model selection. The proposed scheme visualizes the underlying PEL regarding α transitions associated with irreversible cage-breaking events as the cooperative motion of clusters. By characterizing the topological property of the state space network, we observe characteristics of a small-world network. The proposed scheme has a significant potential to enable the understanding of the underlying mechanisms of glass physics, and is analogous to biological networks.

  10. Visualization and evaluation of flow during water filtration: Parameterization and sensitivity analysis

    NASA Astrophysics Data System (ADS)

    Bílek, Petr

    2016-03-01

    This paper deals with visualization and evaluation of flow during filtration of water seeded by artificial microscopic particles. Planar laser induced fluorescence (PLIF) is a wide spread method for visualization and non-invasive characterization of flow. However the method uses fluorescent dyes or fluorescent particles in special cases. In this article the flow is seeded by non-fluorescent monodisperse polystyrene particles with the diameter smaller than one micrometer. The monodisperse sub-micron particles are very suitable for testing of textile filtration materials. Nevertheless non-fluorescent particles are not useful for PLIF method. A water filtration setup with an optical access to the place, were a tested filter is mounted, was built and used for the experiments. Concentration of particles in front of and behind the tested filter in a laser light sheet measured is and the local filtration efficiency expressed is. The article describes further progress in the measurement. It was carried out sensitivity analysis, parameterization and performance of the method during several simulations and experiments.

  11. Flow visualization and wall shear stress of a flapping model hummingbird wing

    NASA Astrophysics Data System (ADS)

    Swanton, Erik W. M.; Vanier, Blake A.; Mohseni, Kamran

    2010-09-01

    The unsteady low Reynolds number aerodynamics of flapping flight was investigated experimentally through flow visualization by suspended particle imagery and wall shear stress measurement from micro-array hot-film anemometry. In conjunction, a mechanism was developed to create a flapping motion with three degrees of freedom and adjustable flapping frequency. The flapping kinematics and wing shape were selected for dynamic similarity to a hummingbird during hovering flight. Flow visualization was used to validate the anemometry observations of leading edge vortex (LEV) characteristics and to investigate the necessity of spanwise flow in LEV stability. The shear sensors determined LEV characteristics throughout the translation section of the stroke period for various wing speeds. It was observed that a minimum frequency between 2 and 3.5 Hz is required for the formation and stabilization of a LEV. The vortex strength peaked around 30% of the flapping cycle (corresponding to just past the translation midpoint), which agrees with results from previous studies conducted by others. The shear sensors also indicated a mild growth in LEV size during translation sections of the wing’s motion. This growth magnitude was nearly constant through a range of operating frequencies.

  12. Visualizing spatial distribution of alectinib in murine brain using quantitative mass spectrometry imaging

    PubMed Central

    Aikawa, Hiroaki; Hayashi, Mitsuhiro; Ryu, Shoraku; Yamashita, Makiko; Ohtsuka, Naoto; Nishidate, Masanobu; Fujiwara, Yasuhiro; Hamada, Akinobu

    2016-01-01

    In the development of anticancer drugs, drug concentration measurements in the target tissue have been thought to be crucial for predicting drug efficacy and safety. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) is commonly used for determination of average drug concentrations; however, complete loss of spatial information in the target tissue occurs. Mass spectrometry imaging (MSI) has been recently applied as an innovative tool for detection of molecular distribution of pharmacological agents in heterogeneous targets. This study examined the intra-brain transitivity of alectinib, a novel anaplastic lymphoma kinase inhibitor, using a combination of matrix-assisted laser desorption ionization–MSI and LC-MS/MS techniques. We first analyzed the pharmacokinetic profiles in FVB mice and then examined the effect of the multidrug resistance protein-1 (MDR1) using Mdr1a/b knockout mice including quantitative distribution of alectinib in the brain. While no differences were observed between the mice for the plasma alectinib concentrations, diffuse alectinib distributions were found in the brain of the Mdr1a/b knockout versus FVB mice. These results indicate the potential for using quantitative MSI for clarifying drug distribution in the brain on a microscopic level, in addition to suggesting a possible use in designing studies for anticancer drug development and translational research. PMID:27026287

  13. Visual hull method for tomographic PIV of flow around moving objects

    NASA Astrophysics Data System (ADS)

    Adhikari, Deepak; Longmire, Ellen

    2011-11-01

    Measurement of velocity around arbitrarily moving objects is of interest in many applications. This includes flow around marine animals and flying insects, flow around supercavitating projectiles, and flow around discrete drops or particles in multiphase flows. We present a visual hull technique that employs existing tomographic PIV reconstruction software to automate identification, masking and tracking of discrete objects within a three-dimensional volume, while allowing computation and avoiding contamination of the surrounding three-component fluid velocity vectors. The technique is demonstrated by considering flow around falling objects of different shape, namely a sphere, cube, tetrahedron and cylinder. Four high-speed cameras and a laser are used to acquire images of these objects falling within liquid seeded with tracer particles. The acquired image sets are then processed to reconstruct both the object and the surrounding tracer particles. The reconstructed object is used to estimate the object location at each time step and mask the reconstructed particle volume, while the reconstructed tracer particles are cross-correlated with subsequent particle volumes to obtain the fluid velocity vectors. Supported by NSF IDBR Grant #0852875.

  14. Quantitating MHC class II trafficking in primary dendritic cells using imaging flow cytometry

    PubMed Central

    Hennies, Cassandra M.; Lehn, Maria A.; Janssen, Edith M.

    2015-01-01

    Presentation of antigenic peptides in MHC class II (MHCII) on dendritic cells (DCs) is the first step in the activation of antigen-specific CD4+T cells. The expression of surface MHCII-peptide complexes is tightly regulated as the frequency of MHCII-peptide complexes can affect the magnitude, as well as the phenotype of the ensuing CD4+T cell response. The surface MHCII-peptide levels are determined by the balance between expression of newly generated complexes, complex internalization, and their subsequent re-emergence or degradation. However, the molecular mechanisms that underpin these processes are still poorly understood. Here we describe a multispectral imaging flow cytometry assay to visualize MHCII trafficking that can be used as a tool to dissect the molecular mechanisms that regulate MHCII homeostasis in primary mouse and human DCs. PMID:25967952

  15. Visualization and quantitative analysis of lung microstructure using micro CT images

    NASA Astrophysics Data System (ADS)

    Yamamoto, Tetsuo; Kubo, Mitsuru; Kawata, Yoshiki; Niki, Noboru; Fujii, Masashi; Nakaya, Yoshihiro; Matsui, Eisuke; Ohmatsu, Hironobu; Moriyama, Noriyuki

    2005-04-01

    Micro CT system is developed for lung function analysis at a high resolution of the micrometer order (up to 5μm in spatial resolution). This system reveals the lung distal structures such as interlobular septa, terminal bronchiole, respiratory bronchiole, alveolar duct, and alveolus. In order to visualize lung 3-D microstructures using micro CT images and to analyze them, this research presents a computerized approach. This approach is applied for to micro CT images of human lung tissue specimens that were obtained by surgical excision and were kept in the state of the inflated fixed lung. This report states a wall area such as bronchus wall and alveolus wall about the extraction technique by using the surface thinning process to analyze the lung microstructures from micro CT images measured by the new-model micro CT system.

  16. Hot gas ingestion characteristics and flow visualization of a vectored thrust STOVL concept

    NASA Technical Reports Server (NTRS)

    Johns, Albert L.; Neiner, George H.; Bencic, Timothy J.; Flood, Joseph D.; Amuedo, Kurt C.; Strock, Thomas W.; Williams, Ben R.

    1990-01-01

    A 9.2 percent scale short takeoff and vertical landing (STOVL) hot gas ingestion model was designed and built by McDonnell Douglas Corporation (MCAIR) and tested in the NASA Lewis Research Center 9- by 15-Foot Low Speed Wind Tunnel (LSWT). Hot gas ingestion, the entrainment of heated engine exhaust into the inlet flow field, is a key development issue for advanced short takeoff and vertical landing aircraft. The Phase 1 test program, conducted by NASA Lewis and McDonnell Douglas Corporation, evaluated the hot ingestion phenomena and control techniques and Phase 2 test program which was conducted by NASA Lewis are both reported. The Phase 2 program was conducted at exhaust nozzles temperatures up to 1460 R and utilized a sheet laser system for flow visualization of the model flow field in and out of ground effects. Hot gas ingestion levels were measured for the several forward nozzle splay configurations and with flow control/lift improvement devices which reduced the hot gas ingestion. The model support system had four degrees of freedom, heated high pressure air for nozzle flow, and a suction system exhaust for inlet flow. The headwind (freestream) velocity for Phase 1 was varied from 8 to 90 kn, with primary data taken in the 8 to 23 kn headwind velocity range. Phase 2 headwind velocity varied from 10 to 23 kn. Results of both Phase 1 and 2 are presented. A description of the model, facility, a new model support system, and a sheet laser illumination system are also provided. Results are presented over a range of main landing gear height (model height) above the ground plane at a 10 kn headwind velocity. The results contain the compressor face pressure and temperature distortions, total pressure recovery, compressor face temperature rise, and the environmental effects of the hot gas. The environmental effects include the ground plane temperature and pressure distributions, model airframe heating, and the location of the ground flow separation. Results from the

  17. A simplified holographic-interferometry technique for real-time flow visualization and analysis

    NASA Technical Reports Server (NTRS)

    Long, S. A.; Spencer, R. C.

    1974-01-01

    A holographic-interferometry technique for flow visualization and analysis that produces real-time moire fringes is described from both experimental and application considerations. It has three chief advantages: real-time data for continuous observation and photography, ease of optical adjustment, and capability of using ordinary-glass test-section windows without affecting the results. A theoretical discussion is presented describing the formation of the fringes in holographic terms and then comparing this result to that which is obtained from a conventional moire approach. A discussion on obtaining density information from the fringe pattern is also included.

  18. Cartography of high-dimensional flows: a visual guide to sections and slices.

    PubMed

    Cvitanović, Predrag; Borrero-Echeverry, Daniel; Carroll, Keith M; Robbins, Bryce; Siminos, Evangelos

    2012-12-01

    Symmetry reduction by the method of slices quotients the continuous symmetries of chaotic flows by replacing the original state space by a set of charts, each covering a neighborhood of a dynamically important class of solutions, qualitatively captured by a "template." Together these charts provide an atlas of the symmetry-reduced "slice" of state space, charting the regions of the manifold explored by the trajectories of interest. Within the slice, relative equilibria reduce to equilibria and relative periodic orbits reduce to periodic orbits. Visualizations of these solutions and their unstable manifolds reveal their interrelations and the role they play in organizing turbulence/chaos.

  19. Hummingbirds generate bilateral vortex loops during hovering: evidence from flow visualization

    NASA Astrophysics Data System (ADS)

    Pournazeri, Sam; Segre, Paolo S.; Princevac, Marko; Altshuler, Douglas L.

    2012-12-01

    Visualization of the vortex wake of a flying animal provides understanding of how wingbeat kinematics are translated into the aerodynamic forces for powering and controlling flight. Two general vortex flow patterns have been proposed for the wake of hovering hummingbirds: (1) The two wings form a single, merged vortex ring during each wing stroke; and (2) the two wings form bilateral vortex loops during each wing stroke. The second pattern was proposed after a study with particle image velocimetry that demonstrated bilateral source flows in a horizontal measurement plane underneath hovering Anna's hummingbirds ( Calypte anna). Proof of this hypothesis requires a clear perspective of bilateral pairs of vortices. Here, we used high-speed image sequences (500 frames per second) of C. anna hover feeding within a white plume to visualize the vortex wake from multiple perspectives. The films revealed two key structural features: (1) Two distinct jets of downwards airflow are present under each wing; and (2) vortex loops around each jet are shed during each upstroke and downstroke. To aid in the interpretation of the flow visualization data, we analyzed high-speed kinematic data (1,000 frames per second) of wing tips and wing roots as C. anna hovered in normal air. These data were used to refine several simplified models of vortex topology. The observed flow patterns can be explained by either a single loop model with an hourglass shape or a bilateral model, with the latter being more likely. When hovering in normal air, hummingbirds used an average stroke amplitude of 153.6° (range 148.9°-164.4°) and a wingbeat frequency of 38.5 Hz (range 38.1-39.1 Hz). When hovering in the white plume, hummingbirds used shallower stroke amplitudes ( bar{x} = 129.8°, range 116.3°-154.1°) and faster wingbeat frequencies ( bar{x} = 41.1 Hz, range 38.5-44.7 Hz), although the bilateral jets and associated vortices were observed across the full kinematic range. The plume did not

  20. Hummingbirds generate bilateral vortex loops during hovering: evidence from flow visualization

    NASA Astrophysics Data System (ADS)

    Pournazeri, Sam; Segre, Paolo S.; Princevac, Marko; Altshuler, Douglas L.

    2013-01-01

    Visualization of the vortex wake of a flying animal provides understanding of how wingbeat kinematics are translated into the aerodynamic forces for powering and controlling flight. Two general vortex flow patterns have been proposed for the wake of hovering hummingbirds: (1) The two wings form a single, merged vortex ring during each wing stroke; and (2) the two wings form bilateral vortex loops during each wing stroke. The second pattern was proposed after a study with particle image velocimetry that demonstrated bilateral source flows in a horizontal measurement plane underneath hovering Anna's hummingbirds ( Calypte anna). Proof of this hypothesis requires a clear perspective of bilateral pairs of vortices. Here, we used high-speed image sequences (500 frames per second) of C. anna hover feeding within a white plume to visualize the vortex wake from multiple perspectives. The films revealed two key structural features: (1) Two distinct jets of downwards airflow are present under each wing; and (2) vortex loops around each jet are shed during each upstroke and downstroke. To aid in the interpretation of the flow visualization data, we analyzed high-speed kinematic data (1,000 frames per second) of wing tips and wing roots as C. anna hovered in normal air. These data were used to refine several simplified models of vortex topology. The observed flow patterns can be explained by either a single loop model with an hourglass shape or a bilateral model, with the latter being more likely. When hovering in normal air, hummingbirds used an average stroke amplitude of 153.6° (range 148.9°-164.4°) and a wingbeat frequency of 38.5 Hz (range 38.1-39.1 Hz). When hovering in the white plume, hummingbirds used shallower stroke amplitudes ( bar{x} = 129.8°, range 116.3°-154.1°) and faster wingbeat frequencies ( bar{x} = 41.1 Hz, range 38.5-44.7 Hz), although the bilateral jets and associated vortices were observed across the full kinematic range. The plume did not

  1. Application of Least-Squares Adjustment Technique to Geometric Camera Calibration and Photogrammetric Flow Visualization

    NASA Technical Reports Server (NTRS)

    Chen, Fang-Jenq

    1997-01-01

    Flow visualization produces data in the form of two-dimensional images. If the optical components of a camera system are perfect, the transformation equations between the two-dimensional image and the three-dimensional object space are linear and easy to solve. However, real camera lenses introduce nonlinear distortions that affect the accuracy of transformation unless proper corrections are applied. An iterative least-squares adjustment algorithm is developed to solve the nonlinear transformation equations incorporated with distortion corrections. Experimental applications demonstrate that a relative precision on the order of 40,000 is achievable without tedious laboratory calibrations of the camera.

  2. Calibration plot for proteomics: A graphical tool to visually check the assumptions underlying FDR control in quantitative experiments.

    PubMed

    Giai Gianetto, Quentin; Combes, Florence; Ramus, Claire; Bruley, Christophe; Couté, Yohann; Burger, Thomas

    2016-01-01

    In MS-based quantitative proteomics, the FDR control (i.e. the limitation of the number of proteins that are wrongly claimed as differentially abundant between several conditions) is a major postanalysis step. It is classically achieved thanks to a specific statistical procedure that computes the adjusted p-values of the putative differentially abundant proteins. Unfortunately, such adjustment is conservative only if the p-values are well-calibrated; the false discovery control being spuriously underestimated otherwise. However, well-calibration is a property that can be violated in some practical cases. To overcome this limitation, we propose a graphical method to straightforwardly and visually assess the p-value well-calibration, as well as the R codes to embed it in any pipeline. All MS data have been deposited in the ProteomeXchange with identifier PXD002370 (http://proteomecentral.proteomexchange.org/dataset/PXD002370).

  3. Three-dimensional visualization and quantitation of fibrin in solid tumors by confocal laser scanning microscopy.

    PubMed

    Biggerstaff, J; Amirkhosravi, A; Francis, J L

    1997-10-01

    Fibrin forms part of the stroma essential for growth of solid tumors. Anticoagulants reduce primary tumor growth and tumor metastasis in murine and some human tumors. These effects may be partly mediated by reduction of intra-tumor fibrin, although there are no quantitative data to support this hypothesis. We therefore evaluated the effect of warfarin on fibrin deposition in a subcutaneously (s.c.) implanted murine tumor using confocal laser scanning microscopy (CLSM). AJ mice received no treatment (n = 6) or sodium warfarin (3.5 mg/L in drinking water, n = 5). All animals received 2 x 10(6) syngeneic Neuro2a neuroblastoma cells s.c. After 14 days, primary tumors were excised and placed in liquid nitrogen. Warfarin treatment resulted in a small, but significant (P < 0.05), decrease in wet tumor weight. Frozen sections (20 microns) were incubated with goat anti-mouse fibrin(ogen) or normal goat serum (isotypic control) and stained with FITC-conjugated rabbit anti-goat antibody. Using a Multiprobe 2001 CLSM (Molecular Dynamics, Sunnyvale, CA), 20 serial optical sections were taken from five, randomly chosen, high power fields (60x objective) for each slide. A threshold excluded all fluorescence except that from structural components within the tumor stroma (fibrin). The volume of fibrin in each section series was determined, and the percentage of tumor volume occupied by fibrin calculated. Intra- and inter-assay variation were assessed on serial frozen tumor sections from an untreated animal. The percentage fibrin volume was not significantly different among or within experiments, indicating that the procedure was reproducible. In controls, the median (range) volume occupied by fibrin was 8.1% (2.4-22.3%), whereas in anticoagulated animals, this was reduced to 3.7% (0.4-14.0%; P < 0.001). This is the first quantitative demonstration that warfarin reduces fibrin deposition in solid tumors. We conclude that three-dimensional CLSM is useful for the quantitation of

  4. Three-dimensional visualization and quantitation of fibrin in solid tumors by confocal laser scanning microscopy.

    PubMed

    Biggerstaff, J; Amirkhosravi, A; Francis, J L

    1997-10-01

    Fibrin forms part of the stroma essential for growth of solid tumors. Anticoagulants reduce primary tumor growth and tumor metastasis in murine and some human tumors. These effects may be partly mediated by reduction of intra-tumor fibrin, although there are no quantitative data to support this hypothesis. We therefore evaluated the effect of warfarin on fibrin deposition in a subcutaneously (s.c.) implanted murine tumor using confocal laser scanning microscopy (CLSM). AJ mice received no treatment (n = 6) or sodium warfarin (3.5 mg/L in drinking water, n = 5). All animals received 2 x 10(6) syngeneic Neuro2a neuroblastoma cells s.c. After 14 days, primary tumors were excised and placed in liquid nitrogen. Warfarin treatment resulted in a small, but significant (P < 0.05), decrease in wet tumor weight. Frozen sections (20 microns) were incubated with goat anti-mouse fibrin(ogen) or normal goat serum (isotypic control) and stained with FITC-conjugated rabbit anti-goat antibody. Using a Multiprobe 2001 CLSM (Molecular Dynamics, Sunnyvale, CA), 20 serial optical sections were taken from five, randomly chosen, high power fields (60x objective) for each slide. A threshold excluded all fluorescence except that from structural components within the tumor stroma (fibrin). The volume of fibrin in each section series was determined, and the percentage of tumor volume occupied by fibrin calculated. Intra- and inter-assay variation were assessed on serial frozen tumor sections from an untreated animal. The percentage fibrin volume was not significantly different among or within experiments, indicating that the procedure was reproducible. In controls, the median (range) volume occupied by fibrin was 8.1% (2.4-22.3%), whereas in anticoagulated animals, this was reduced to 3.7% (0.4-14.0%; P < 0.001). This is the first quantitative demonstration that warfarin reduces fibrin deposition in solid tumors. We conclude that three-dimensional CLSM is useful for the quantitation of

  5. Visualization of Atomization Gas Flow and Melt Break-up Effects in Response to Nozzle Design

    SciTech Connect

    Anderson, Iver; Rieken, Joel; Meyer, John; Byrd, David; Heidloff, Andy

    2011-04-01

    Both powder particle size control and efficient use of gas flow energy are highly prized goals for gas atomization of metal and alloy powder to minimize off-size powder inventory (or 'reverb') and excessive gas consumption. Recent progress in the design of close-coupled gas atomization nozzles and the water model simulation of melt feed tubes were coupled with previous results from several types of gas flow characterization methods, e.g., aspiration measurements and gas flow visualization, to make progress toward these goals. Size distribution analysis and high speed video recordings of gas atomization reaction synthesis (GARS) experiments on special ferritic stainless steel alloy powders with an Ar+O{sub 2} gas mixture were performed to investigate the operating mechanisms and possible advantages of several melt flow tube modifications with one specific gas atomization nozzle. In this study, close-coupled gas atomization under closed wake gas flow conditions was demonstrated to produce large yields of ultrafine (dia.<20 {mu}m) powders (up to 32%) with moderate standard deviations (1.62 to 1.99). The increased yield of fine powders is consistent with the dual atomization mechanisms of closed wake gas flow patterns in the near-field of the melt orifice. Enhanced size control by stabilized pre-filming of the melt with a slotted trumpet bell pour tube was not clearly demonstrated in the current experiments, perhaps confounded by the influence of the melt oxidation reaction that occurred simultaneously with the atomization process. For this GARS variation of close-coupled gas atomization, it may be best to utilize the straight cylindrical pour tube and closed wake operation of an atomization nozzle with higher gas mass flow to promote the maximum yields of ultrafine powders that are preferred for the oxide dispersion strengthened alloys made from these powders.

  6. Flow visualization studies of blowing from the tip of a swept wing

    NASA Technical Reports Server (NTRS)

    Smith, Jeannette W.; Mineck, Raymond E.; Neuhart, Dan H.

    1990-01-01

    Flow visualization studies of blowing from the tip of a swept wing were conducted in the Langley 16- by 24-inch water tunnel. Four wing tips, each with two independent blowing slots, were tested. The two slots were located one behind the other in the chordwise direction. The wing tips were designed to vary systematically the jet length, the jet in-plane exhaust direction (sweep), and the jet out-of-plane exhaust direction (anhedral). Each blowing slot was tested separately at two angles of attack and at four ratios of jet to free stream velocity ratios. Limited tests were conducted with blowing from both slots simultaneously. Blowing from the tip inhibited inboard spanwise flow on the upper wing surface near the tip. The jet path moved farther away from the tip with increasing jet to free stream velocity ratio and moved closer to the tip with increasing angle of attack.

  7. ScyFlow: An Environment for the Visual Specification and Execution of Scientific Workflows

    NASA Technical Reports Server (NTRS)

    McCann, Karen M.; Yarrow, Maurice; DeVivo, Adrian; Mehrotra, Piyush

    2004-01-01

    With the advent of grid technologies, scientists and engineers are building more and more complex applications to utilize distributed grid resources. The core grid services provide a path for accessing and utilizing these resources in a secure and seamless fashion. However what the scientists need is an environment that will allow them to specify their application runs at a high organizational level, and then support efficient execution across any given set or sets of resources. We have been designing and implementing ScyFlow, a dual-interface architecture (both GUT and APT) that addresses this problem. The scientist/user specifies the application tasks along with the necessary control and data flow, and monitors and manages the execution of the resulting workflow across the distributed resources. In this paper, we utilize two scenarios to provide the details of the two modules of the project, the visual editor and the runtime workflow engine.

  8. Visualization and quantification of two-phase flow in transparent miniature packed beds.

    PubMed

    Zhu, Peixi; Papadopoulos, Kyriakos D

    2012-10-01

    Optical microscopy was used to visualize the flow of two phases [British Petroleum (BP) oil and an aqueous surfactant phase] in confined space, three-dimensional, transparent, natural porous media. The porous media consisted of water-wet cryolite grains packed inside cylindrical, glass microchannels, thus producing microscopic packed beds. Primary drainage of BP oil displacing an aqueous surfactant phase was studied at capillary numbers that varied between 10(-6) and 10(-2). The confinement space had a significant effect on the flow behavior. Phenomena of burst motion and capillary fingering were observed for low capillary numbers due to the domination of capillary forces. It was discovered that breakthrough time and capillary number bear a log-log scale linear relationship, based on which a generalized correlation between oil travel distance x and time t was found empirically.

  9. Streakline flow visualization of discrete hole film cooling with holes inclined 30 deg to surface

    NASA Technical Reports Server (NTRS)

    Colladay, R. S.; Russell, L. M.; Lane, J. M.

    1976-01-01

    Film injection from three rows of discrete holes angled 30 deg to the surface in line with mainstream flow and spaced 5 diameters apart in a staggered array was visualized by using helium bubbles as tracer particles. Both the main stream and the film injectant were ambient air. Detailed streaklines showing the turbulent motion of the film mixing with the main stream were obtained by photographing small, neutrally buoyant helium-filled soap bubbles which followed the flow field. The ratio of boundary layer thickness to hole diameter and the Reynolds number were typical of gas turbine film cooling applications. The results showed the behavior of the film and its interaction with the main stream for a range of blowing rates and two initial boundary layer thicknesses.

  10. Applications of digital holography in visualized measurement of acoustic and flow fields

    NASA Astrophysics Data System (ADS)

    Zhao, Jianlin; Li, Enpu; Sun, Weiwei; Di, Jianglei

    2010-03-01

    Digital holography allows recording the hologram using digitally imaging devices such as CCD, and reconstructing the holographic image by numerically simulating the diffraction of the hologram. Its main advantages are by which one can directly obtain the complex amplitude distribution of the object field, so that more impersonally measure the detail information of the object field, such as the distribution of the refractive index changing in crystals induced by light irradiation, deformation of the object surface, particle distribution, as well as acoustic field, flow field and temperature distribution in air. In this paper, we summarize the principle and some of our experimental results on the applications of digital holography in visualized measurement of acoustic standing wave (acoustic levitation field), plasma plume and water flow (Karman vortex street) fields.

  11. Applications of digital holography in visualized measurement of acoustic and flow fields

    NASA Astrophysics Data System (ADS)

    Zhao, Jianlin; Li, Enpu; Sun, Weiwei; di, Jianglei

    2009-12-01

    Digital holography allows recording the hologram using digitally imaging devices such as CCD, and reconstructing the holographic image by numerically simulating the diffraction of the hologram. Its main advantages are by which one can directly obtain the complex amplitude distribution of the object field, so that more impersonally measure the detail information of the object field, such as the distribution of the refractive index changing in crystals induced by light irradiation, deformation of the object surface, particle distribution, as well as acoustic field, flow field and temperature distribution in air. In this paper, we summarize the principle and some of our experimental results on the applications of digital holography in visualized measurement of acoustic standing wave (acoustic levitation field), plasma plume and water flow (Karman vortex street) fields.

  12. A chemical method for flow visualization and determination of local mass transfer

    NASA Astrophysics Data System (ADS)

    Kottke, V.

    A method for measuring local mass transfer is presented, and the physical and chemical concept behind the measuring technique for reaction gases, such as ammonia or methylamine, are discussed, based on absorption, chemical reactions, and coupled-color reactions. Flow visualization at surfaces of arbitrary shape is evident by the color intensity distribution, which corresponds to the locally transferred mass rate. The technique is characterized by its simple handling, good local accuracy, and high local resolution. As an example, the effects of turbulence intensity on the formation of longitudinal vortices in stagnation flows and on the length of separation bubbles for a flat plate with a semi-circular nose section are discussed. Finally the influence of concentration and the temperature boundary layer at separation on the maximum of mass or heat transfer is described.

  13. Visual confrontation naming and hippocampal function: A neural network study using quantitative (1)H magnetic resonance spectroscopy.

    PubMed

    Sawrie, S M; Martin, R C; Gilliam, F G; Faught, R E; Maton, B; Hugg, J W; Bush, N; Sinclair, K; Kuzniecky, R I

    2000-04-01

    Prior research on the relationship between visual confrontation naming and hippocampal function has been inconclusive. The present study examined this relationship using quantitative (1)H magnetic resonance spectroscopy ((1)H-MRS) to operationalize the function of the left and right hippocampi. The 60-item Boston Naming Test (BNT) was used to measure naming. Our sample included 46 patients with medically intractable, focal mesial temporal lobe epilepsy who had been screened for all pathology other than mesial temporal sclerosis. Statistics included Pearson correlations and neural network analysis (multilayer perceptron and radial basis function). Baseline BNT performance correlated significantly with left (1)H-MRS hippocampal ratios. Thirty-six per cent of the variance in baseline BNT performance was explained by a neural network model using left and right (1)H-MRS ratios(creatine/N-acetylaspartate) as input. This was elevated to 49% when input from the right hippocampus was lesioned mathematically. In a second model, left (1)H-MRS hippocampal ratios were modelled using measures of semantic and episodic memory as input (including the BNT). Explained variance in left (1)H-MRS hippocampal ratios fell from 60.8 to 3.6% when input from BNT and another semantic memory measure was degraded mathematically. These results provide evidence that the speech-dominant hippocampus is a significant component of the overall neuroanatomical network of visual confrontation naming. Clinical and theoretical implications are explored.

  14. Visualization of regional cerebrospinal fluid flow with a dye injection technique in focal arachnoid pathologies.

    PubMed

    Yamaguchi, Satoshi; Hida, Kazutoshi; Takeda, Masaaki; Mitsuhara, Takafumi; Morishige, Mizuki; Yamada, Naoto; Kurisu, Kaoru

    2015-05-01

    Surgical lysis of the thickened arachnoid membrane is the first choice of treatment in spinal arachnoid pathologies that cause flow disturbances or blockage of CSF. However, it is important to consider that while extensive lysis of the arachnoid may temporarily provide a wide pathway for CSF, an extensive lytic procedure may later cause secondary adhesion. Thus, it is ideal for the proper extent of the arachnoid lysis to be determined after careful analysis of regional CSF flow. The authors report their limited experience with intraoperative visualization of CSF flow in spinal arachnoid pathologies. Two patients with a dorsal arachnoid web (DAW) with cervical syringomyelia and 1 patient with focal adhesive arachnoiditis causing edema of the spinal cord were surgically treated at the authors' institution between 2007 and 2013. In all cases, the presence of a DAW or focal adhesive arachnoiditis was suspected from the findings on MRI, namely 1) an indentation on the upper thoracic spinal cord and 2) syringomyelia and/or edema of the spinal cord above the indentation. Exploratory surgery disclosed a transversely thickened arachnoid septum on the dorsal side of the indented cord. To prove blockage of the CSF by the septum and to decide on the extent of arachnoid lysis, regional CSF flow around the arachnoid septum was visualized by subarachnoid injection of gentian violet solution close to the web. Injected dye stagnated just close to the arachnoid septum in all cases, and these findings documented CSF blockage by the septum. In 2 cases, a 2-minute observation showed that the injected dye stayed close to the web without diffusion. The authors performed not only resection of the web itself but also lysis of the thickened arachnoid on both sides of the spinal cord to make a CSF pathway on the ventral side. In the third case, the dye stagnated close to the web at first but then diffused through the nerve root to the ventral CSF space. The lysis procedure was completed

  15. Overland flow dynamics through visual observation using time-lapse photographs

    NASA Astrophysics Data System (ADS)

    Silasari, Rasmiaditya; Blöschl, Günter

    2016-04-01

    Overland flow process on agricultural land is important to be investigated as it affects the stream discharge and water quality assessment. During rainfall events the formation of overland flow may happen through different processes (i.e. Hortonian or saturation excess overland flow) based on the governing soil hydraulic parameters (i.e. soil infiltration rate, soil water capacity). The dynamics of the soil water state and the processes will affect the surface runoff response which can be analyzed visually by observing the saturation patterns with a camera. Although visual observation was proven useful in laboratory experiments, the technique is not yet assessed for natural rainfall events. The aim of this work is to explore the use of time-lapse photographs of naturally occurring-saturation patterns in understanding the threshold processes of overland flow generation. The image processing produces orthographic projection of the saturation patterns which will be used to assess the dynamics of overland flow formation in relation with soil moisture state and rainfall magnitude. The camera observation was performed at Hydrological Open Air Laboratory (HOAL) catchment at Petzenkirchen, Lower Austria. The catchment covers an area of 66 ha dominated with agricultural land (87%). The mean annual precipitation and mean annual flow at catchment outlet are 750 mm and 4 l/s, respectively. The camera was set to observe the overland flow along a thalweg on an arable field which was drained in 1950s and has advantages of: (1) representing agricultural land as the dominant part of the catchment, (2) adjacent to the stream with clear visibility (no obstructing objects, such as trees), (3) drained area provides extra cases in understanding the response of tile drain outflow to overland flow formation and vice versa, and (4) in the vicinity of TDT soil moisture stations. The camera takes a picture with 1280 x 720 pixels resolution every minute and sends it directly in a PC via fiber

  16. PolarBRDF: A general purpose Python package for visualization and quantitative analysis of multi-angular remote sensing measurements

    NASA Astrophysics Data System (ADS)

    Singh, Manoj K.; Gautam, Ritesh; Gatebe, Charles K.; Poudyal, Rajesh

    2016-11-01

    The Bidirectional Reflectance Distribution Function (BRDF) is a fundamental concept for characterizing the reflectance property of a surface, and helps in the analysis of remote sensing data from satellite, airborne and surface platforms. Multi-angular remote sensing measurements are required for the development and evaluation of BRDF models for improved characterization of surface properties. However, multi-angular data and the associated BRDF models are typically multidimensional involving multi-angular and multi-wavelength information. Effective visualization of such complex multidimensional measurements for different wavelength combinations is presently somewhat lacking in the literature, and could serve as a potentially useful research and teaching tool in aiding both interpretation and analysis of BRDF measurements. This article describes a newly developed software package in Python (PolarBRDF) to help visualize and analyze multi-angular data in polar and False Color Composite (FCC) forms. PolarBRDF also includes functionalities for computing important multi-angular reflectance/albedo parameters including spectral albedo, principal plane reflectance and spectral reflectance slope. Application of PolarBRDF is demonstrated using various case studies obtained from airborne multi-angular remote sensing measurements using NASA's Cloud Absorption Radiometer (CAR). Our visualization program also provides functionalities for untangling complex surface/atmosphere features embedded in pixel-based remote sensing measurements, such as the FCC imagery generation of BRDF measurements of grasslands in the presence of wildfire smoke and clouds. Furthermore, PolarBRDF also provides quantitative information of the angular distribution of scattered surface/atmosphere radiation, in the form of relevant BRDF variables such as sunglint, hotspot and scattering statistics.

  17. Flow Visualization Studies in the Novacor Left Ventricular Assist System CRADA PC91-002, Final Report

    SciTech Connect

    Borovetz, H.S.; Shaffer, F.; Schaub, R.; Lund, L.; Woodard, J.

    1999-01-01

    This paper discusses a series of experiments to visualize and measure flow fields in the Novacor left ventricular assist system (LVAS). The experiments utilize a multiple exposure, optical imaging technique called fluorescent image tracking velocimetry (FITV) to hack the motion of small, neutrally-buoyant particles in a flowing fluid.

  18. A Rapid and Quantitative Flow Cytometry Method for the Analysis of Membrane Disruptive Antimicrobial Activity

    PubMed Central

    O’Brien-Simpson, Neil M.; Pantarat, Namfon; Attard, Troy J.; Walsh, Katrina A.; Reynolds, Eric C.

    2016-01-01

    We describe a microbial flow cytometry method that quantifies within 3 hours antimicrobial peptide (AMP) activity, termed Minimum Membrane Disruptive Concentration (MDC). Increasing peptide concentration positively correlates with the extent of bacterial membrane disruption and the calculated MDC is equivalent to its MBC. The activity of AMPs representing three different membranolytic modes of action could be determined for a range of Gram positive and negative bacteria, including the ESKAPE pathogens, E. coli and MRSA. By using the MDC50 concentration of the parent AMP, the method provides high-throughput, quantitative screening of AMP analogues. A unique feature of the MDC assay is that it directly measures peptide/bacteria interactions and lysed cell numbers rather than bacteria survival as with MIC and MBC assays. With the threat of multi-drug resistant bacteria, this high-throughput MDC assay has the potential to aid in the development of novel antimicrobials that target bacteria with improved efficacy. PMID:26986223

  19. A Rapid and Quantitative Flow Cytometry Method for the Analysis of Membrane Disruptive Antimicrobial Activity.

    PubMed

    O'Brien-Simpson, Neil M; Pantarat, Namfon; Attard, Troy J; Walsh, Katrina A; Reynolds, Eric C

    2016-01-01

    We describe a microbial flow cytometry method that quantifies within 3 hours antimicrobial peptide (AMP) activity, termed Minimum Membrane Disruptive Concentration (MDC). Increasing peptide concentration positively correlates with the extent of bacterial membrane disruption and the calculated MDC is equivalent to its MBC. The activity of AMPs representing three different membranolytic modes of action could be determined for a range of Gram positive and negative bacteria, including the ESKAPE pathogens, E. coli and MRSA. By using the MDC50 concentration of the parent AMP, the method provides high-throughput, quantitative screening of AMP analogues. A unique feature of the MDC assay is that it directly measures peptide/bacteria interactions and lysed cell numbers rather than bacteria survival as with MIC and MBC assays. With the threat of multi-drug resistant bacteria, this high-throughput MDC assay has the potential to aid in the development of novel antimicrobials that target bacteria with improved efficacy. PMID:26986223

  20. A flexible quantitative methodology for the analysis of gene-flow between conventionally bred maize populations using microsatellite markers.

    PubMed

    Robson, P R H; Kelly, R; Jensen, E F; Giddings, G D; Leitch, M; Davey, C; Gay, A P; Jenkins, G; Thomas, H; Donnison, I S

    2011-03-01

    Previous studies of gene-flow in agriculture have used a range of physical and biochemical markers, including transgenes. However, physical and biochemical markers are not available for all commercial varieties, and transgenes are difficult to use when trying to estimate gene flow in the field where the use of transgenes is often restricted. Here, we demonstrate the use of simple sequence repeat microsatellite markers (SSRs) to study gene flow in maize. Developing the first quantitative analysis of pooled SSR samples resulted in a high sampling efficiency which minimised the use of resources and greatly enhanced the possibility of hybrid detection. We were able to quantitatively distinguish hybrids in pools of ten samples from non-hybrid parental lines in all of the 24 pair-wise combinations of commercial varieties tested. The technique was used to determine gene flow in field studies, from which a simple model describing gene flow in maize was developed. PMID:21109994

  1. An Improved Flow Cytometry Method For Precise Quantitation Of Natural-Killer Cell Activity

    NASA Technical Reports Server (NTRS)

    Crucian, Brian; Nehlsen-Cannarella, Sandra; Sams, Clarence

    2006-01-01

    The ability to assess NK cell cytotoxicity using flow cytometry has been previously described and can serve as a powerful tool to evaluate effector immune function in the clinical setting. Previous methods used membrane permeable dyes to identify target cells. The use of these dyes requires great care to achieve optimal staining and results in a broad spectral emission that can make multicolor cytometry difficult. Previous methods have also used negative staining (the elimination of target cells) to identify effector cells. This makes a precise quantitation of effector NK cells impossible due to the interfering presence of T and B lymphocytes, and the data highly subjective to the variable levels of NK cells normally found in human peripheral blood. In this study an improved version of the standard flow cytometry assay for NK activity is described that has several advantages of previous methods. Fluorescent antibody staining (CD45FITC) is used to positively identify target cells in place of membranepermeable dyes. Fluorescent antibody staining of target cells is less labor intensive and more easily reproducible than membrane dyes. NK cells (true effector lymphocytes) are also positively identified by fluorescent antibody staining (CD56PE) allowing a simultaneous absolute count assessment of both NK cells and target cells. Dead cells are identified by membrane disruption using the DNA intercalating dye PI. Using this method, an exact NK:target ratio may be determined for each assessment, including quantitation of NK target complexes. Backimmunoscatter gating may be used to track live vs. dead Target cells via scatter properties. If desired, NK activity may then be normalized to standardized ratios for clinical comparisons between patients, making the determination of PBMC counts or NK cell percentages prior to testing unnecessary. This method provides an exact cytometric determination of NK activity that highly reproducible and may be suitable for routine use in the

  2. A novel anthropomorphic flow phantom for the quantitative evaluation of prostate DCE-MRI acquisition techniques

    NASA Astrophysics Data System (ADS)

    Knight, Silvin P.; Browne, Jacinta E.; Meaney, James F.; Smith, David S.; Fagan, Andrew J.

    2016-10-01

    A novel anthropomorphic flow phantom device has been developed, which can be used for quantitatively assessing the ability of magnetic resonance imaging (MRI) scanners to accurately measure signal/concentration time-intensity curves (CTCs) associated with dynamic contrast-enhanced (DCE) MRI. Modelling of the complex pharmacokinetics of contrast agents as they perfuse through the tumour capillary network has shown great promise for cancer diagnosis and therapy monitoring. However, clinical adoption has been hindered by methodological problems, resulting in a lack of consensus regarding the most appropriate acquisition and modelling methodology to use and a consequent wide discrepancy in published data. A heretofore overlooked source of such discrepancy may arise from measurement errors of tumour CTCs deriving from the imaging pulse sequence itself, while the effects on the fidelity of CTC measurement of using rapidly-accelerated sequences such as parallel imaging and compressed sensing remain unknown. The present work aimed to investigate these features by developing a test device in which ‘ground truth’ CTCs were generated and presented to the MRI scanner for measurement, thereby allowing for an assessment of the DCE-MRI protocol to accurately measure this curve shape. The device comprised a four-pump flow system wherein CTCs derived from prior patient prostate data were produced in measurement chambers placed within the imaged volume. The ground truth was determined as the mean of repeat measurements using an MRI-independent, custom-built optical imaging system. In DCE-MRI experiments, significant discrepancies between the ground truth and measured CTCs were found for both tumorous and healthy tissue-mimicking curve shapes. Pharmacokinetic modelling revealed errors in measured K trans, v e and k ep values of up to 42%, 31%, and 50% respectively, following a simple variation of the parallel imaging factor and number of signal averages in the acquisition

  3. Time-series tropical forest change detection: a visual and quantitative approach

    NASA Astrophysics Data System (ADS)

    Sader, Steven A.; Sever, Thomas; Smoot, James C.

    1996-11-01

    Forest change detection over a decadal time frame was conducted for the Maya Biosphere Reserve in northern Guatemala. A simple and logical method of visualizing and quantifying forest change is presented. Analysis of time- series Landsat-Thematic Mapper imagery provided estimates of forest change at three time periods; prior to 1990, 1990 to 1993 and 1993 to 1995. Four dates of Landsat imagery were pre-processed, co-registered to a UTM projection and the normalized difference vegetation index was computed for each date. An unsupervised classification was performed and cluster classes were grouped into time-series change/no change categories. A color coded image was generated which resembled the RBG-NDVI color composite of the 1990, 1993, and 1995 imagery. Land cover information and Geographic Information System (GIS) editing techniques were applied to resolve some confusions between forest change and change in non-forest types. Results indicated that forest clearing rates in the reserve were less than 0.5 percent per year in the early to mid 1990s but the buffer zone clearing rates, at over two percent, were much higher.

  4. Quantitative assessment of intrinsic noise for visually guided behaviour in zebrafish.

    PubMed

    Spilioti, Melissa; Vargesson, Neil; Neri, Peter

    2016-10-01

    All sensory devices, whether biological or artificial, carry appreciable amounts of intrinsic noise. When these internally generated perturbations are sufficiently large, the behaviour of the system is not solely driven by the external stimulus but also by its own spontaneous variability. Behavioural internal noise can be quantified, provided it is expressed in relative units of the noise source externally applied by the stimulus. In humans performing sensory tasks at near threshold performance, the size of internal noise is roughly equivalent to the size of the response fluctuations induced by the external noise source. It is not known how the human estimate compares with other animals, because behavioural internal noise has never been measured in other species. We have adapted the methodology used with humans to the zebrafish, a small teleost that displays robust visually-guided behaviour. Our measurements demonstrate that, under some conditions, it is possible to obtain viable estimates of internal noise in this vertebrate species; the estimates generally fall within the human range, suggesting that the properties of internal noise may reflect general constraints on stimulus-response coupling that apply across animal systems with substantially different characteristics. PMID:27491704

  5. Traces: making sense of urodynamics testing--Part 11: quantitative analysis of micturition via the voiding pressure flow study: pressure-flow nomograms.

    PubMed

    Gray, Mikel

    2012-01-01

    The voiding pressure flow study is the gold standard for evaluating micturition. Part 10 of the Traces series described techniques for evaluating micturition via the voiding pressure flow study; it focused on interpretation of results qualitatively via inspection and classification of flow pattern, detrusor contraction amplitude and duration, pelvic floor muscle response to voiding, and urethral resistance. This article discusses quantitative analysis of the voiding pressure flow study using nomograms that measure the magnitude of urethral resistance (bladder outflow obstruction) and/or detrusor contraction strength.

  6. Development of quantitative radioactive methodologies on paper to determine important lateral-flow immunoassay parameters.

    PubMed

    Mosley, Garrett L; Nguyen, Phuong; Wu, Benjamin M; Kamei, Daniel T

    2016-08-01

    The lateral-flow immunoassay (LFA) is a well-established diagnostic technology that has recently seen significant advancements due in part to the rapidly expanding fields of paper diagnostics and paper-fluidics. As LFA-based diagnostics become more complex, it becomes increasingly important to quantitatively determine important parameters during the design and evaluation process. However, current experimental methods for determining these parameters have certain limitations when applied to LFA systems. In this work, we describe our novel methods of combining paper and radioactive measurements to determine nanoprobe molarity, the number of antibodies per nanoprobe, and the forward and reverse rate constants for nanoprobe binding to immobilized target on the LFA test line. Using a model LFA system that detects for the presence of the protein transferrin (Tf), we demonstrate the application of our methods, which involve quantitative experimentation and mathematical modeling. We also compare the results of our rate constant experiments with traditional experiments to demonstrate how our methods more appropriately capture the influence of the LFA environment on the binding interaction. Our novel experimental approaches can therefore more efficiently guide the research process for LFA design, leading to more rapid advancement of the field of paper-based diagnostics.

  7. Resting quantitative cerebral blood flow in schizophrenia measured by pulsed arterial spin labeling perfusion MRI

    PubMed Central

    Pinkham, Amy; Loughead, James; Ruparel, Kosha; Wu, Wen-Chau; Overton, Eve; Gur, Raquel; Gur, Ruben

    2011-01-01

    Arterial spin labeling imaging (ASL) perfusion MRI is a relatively novel technique that can allow for quantitative measurement of cerebral blood flow (CBF) by using magnetically labeled arterial blood water as an endogenous tracer. Available data on resting CBF in schizophrenia primarily comes from invasive and expensive nuclear medicine techniques that are often limited to small samples and yield mixed results. The noninvasive nature of ASL offers promise for larger-scale studies. The utility of this approach was examined in 24 healthy controls and 30 patients with schizophrenia. Differences between groups in quantitative CBF were assessed, as were relationships between CBF and psychiatric symptoms. Group comparisons demonstrated greater CBF for controls in several regions including bilateral precuneus and middle frontal gyrus. Patients showed increased CBF in left putamen/superior corona radiata and right middle temporal gyrus. For patients, greater severity of negative symptoms was associated with reduced CBF in bilateral superior temporal gyrus, cingulate gyrus, and left middle frontal gyrus. Increased severity of positive symptoms was related to both higher CBF in cingulate gyrus and superior frontal gyrus and decreased CBF in precentral gyrus/middle frontal gyrus. These findings support the feasibility and utility of implementing ASL in schizophrenia research and expand upon previous results. PMID:21831608

  8. High-throughput quantitation of intracellular trafficking and organelle disruption by flow cytometry.

    PubMed

    Chia, Pei Zhi Cheryl; Ramdzan, Yasmin M; Houghton, Fiona J; Hatters, Danny M; Gleeson, Paul A

    2014-05-01

    Current methods for the quantitation of membrane protein trafficking rely heavily on microscopy, which has limited quantitative capacity for analyses of cell populations and is cumbersome to perform. Here we describe a simple flow cytometry-based method that circumvents these limitations. The method utilizes fluorescent pulse-width measurements as a highly sensitive indicator to monitor the changes in intracellular distributions of a fluorescently labelled molecule in a cell. Pulse-width analysis enabled us to discriminate cells with target proteins in different intracellular locations including Golgi, lyso-endosomal network and the plasma membrane, as well as detecting morphological changes in organelles such as Golgi perturbation. The movement of endogenous and exogenous retrograde cargo was tracked from the plasma membrane-to-endosomes-to-Golgi, by decreasing pulse-width values. A block in transport upon RNAi-mediated ablation of transport machinery was readily quantified, demonstrating the versatility of this technique to identify pathway inhibitors. We also showed that pulse-width can be exploited to sort and recover cells based on different intracellular staining patterns, e.g. early endosomes and Golgi, opening up novel downstream applications. Overall, the method provides new capabilities for viewing membrane transport in thousands of cells per minute, unbiased analysis of the trafficking of cargo, and the potential for rapid screening of inhibitors of trafficking pathways.

  9. A static air flow visualization method to obtain a time history of the lift-induced vortex and circulation

    NASA Technical Reports Server (NTRS)

    Patterson, J. C., Jr.; Jordan, F. L., Jr.

    1975-01-01

    A recently proposed method of flow visualization was investigated at the National Aeronautics and Space Administration's Langley Research Center. This method of flow visualization is particularly applicable to the study of lift-induced wing tip vortices through which it is possible to record the entire life span of the vortex. To accomplish this, a vertical screen of smoke was produced perpendicular to the flight path and allowed to become stationary. A model was then driven through the screen of smoke producing the circular vortex motion made visible as the smoke was induced along the path taken by the flow and was recorded by highspeed motion pictures.

  10. Flow visualization in the Langley 0.3-meter Transonic Cryogenic Tunnel and preliminary plans for the National Transonic Facility

    NASA Technical Reports Server (NTRS)

    Rhodes, D. B.; Jones, S. B.

    1982-01-01

    Design problems associated with the integration of flow visualization in cryogenic facilities are discussed. The possible effects from the cryogenic environment (i.e., window distortion due to thermal contraction both in the mounts and in the window material itself and turbulence in the flow due to injected LN2) are examined. The flow visualization techniques studied are schlieren, shadowgraph, moire deflectometry, and holographic interferometry. The test beds for this work are a Langley in-house cryogenic test chamber and the 0.3-Meter Transonic Cryogenic Tunnel.

  11. Flow Visualization Experiments in a 4:1 Scale Model of the Canine Nasal Cavity

    NASA Astrophysics Data System (ADS)

    Hargather, Michael; Lawson, Michael; Settles, Gary

    2009-11-01

    An anatomically-correct 4:1 scale model of the canine nasal cavity is used to study flow patterns in the complex nasal airways through dye-streak flow visualization. The nasal cavity geometry was obtained from magnetic resonance imaging (MRI) scans and the model was constructed in sections from a transparent material using a rapid prototyping technique. We believe this model represents the first anatomically-realistic reproduction of the canine nasal cavity, allowing the nasal flowfield to be experimentally studied at a level of detail not previously possible. Olfactory and respiratory flows are observed to take separate paths through the nasal cavity. Respiratory flow through the maxilloturbinates completely bypasses the olfactory region, which amounts to a ``side-sampler.'' A single airway conducts airflow into the olfactory region, whence it slowly filters forward and eventually exits the nasal cavity. The residence time of airflow in the olfactory region varies significantly depending on the specific flowpath taken. The results compare well with computational fluid dynamics (CFD) simulations performed using the same nasal geometry.

  12. Visualization of polymer relaxation in viscoelastic turbulent micro-channel flow

    PubMed Central

    Tai, Jiayan; Lim, Chun Ping; Lam, Yee Cheong

    2015-01-01

    In micro-channels, the flow of viscous liquids e.g. water, is laminar due to the low Reynolds number in miniaturized dimensions. An aqueous solution becomes viscoelastic with a minute amount of polymer additives; its flow behavior can become drastically different and turbulent. However, the molecules are typically invisible. Here we have developed a novel visualization technique to examine the extension and relaxation of polymer molecules at high flow velocities in a viscoelastic turbulent flow. Using high speed videography to observe the fluorescein labeled molecules, we show that viscoelastic turbulence is caused by the sporadic, non-uniform release of energy by the polymer molecules. This developed technique allows the examination of a viscoelastic liquid at the molecular level, and demonstrates the inhomogeneity of viscoelastic liquids as a result of molecular aggregation. It paves the way for a deeper understanding of viscoelastic turbulence, and could provide some insights on the high Weissenberg number problem. In addition, the technique may serve as a useful tool for the investigations of polymer drag reduction. PMID:26563615

  13. Visualization of polymer relaxation in viscoelastic turbulent micro-channel flow

    NASA Astrophysics Data System (ADS)

    Tai, Jiayan; Lim, Chun Ping; Lam, Yee Cheong

    2015-11-01

    In micro-channels, the flow of viscous liquids e.g. water, is laminar due to the low Reynolds number in miniaturized dimensions. An aqueous solution becomes viscoelastic with a minute amount of polymer additives; its flow behavior can become drastically different and turbulent. However, the molecules are typically invisible. Here we have developed a novel visualization technique to examine the extension and relaxation of polymer molecules at high flow velocities in a viscoelastic turbulent flow. Using high speed videography to observe the fluorescein labeled molecules, we show that viscoelastic turbulence is caused by the sporadic, non-uniform release of energy by the polymer molecules. This developed technique allows the examination of a viscoelastic liquid at the molecular level, and demonstrates the inhomogeneity of viscoelastic liquids as a result of molecular aggregation. It paves the way for a deeper understanding of viscoelastic turbulence, and could provide some insights on the high Weissenberg number problem. In addition, the technique may serve as a useful tool for the investigations of polymer drag reduction.

  14. Aerodynamic pressure and flow-visualization measurement from a rotating wind turbine blade

    SciTech Connect

    Butterfield, C P

    1988-11-01

    Aerodynamic, load, flow-visualization, and inflow measurements have been made on a 10-m, three-bladed, downwind, horizontal-axis wind turbine (HAWT). A video camera mounted on the rotor was used to record nighttime and daytime video images of tufts attached to the low-pressure side of a constant-chord, zero-twist blade. Load measurements were made using strain gages mounted at every 10% of the blade's span. Pressure measurements were made at 80% of the blade's span. Pressure taps were located at 32 chordwise positions, revealing pressure distributions comparable with wind tunnel data. Inflow was measured using a vertical-plane array of eight propvane and five triaxial (U-V-W) prop-type anemometers located 10 m upwind in the predominant wind direction. One objective of this comprehensive research program was to study the effects of blade rotation on aerodynamic behavior below, near, and beyond stall. To this end, flow patterns are presented here that reveal the dynamic and steady behavior of flow conditions on the blade. Pressure distributions are compared to flow patterns and two-dimensional wind tunnel data. Separation boundary locations are shown that change as a function of spanwise location, pitch angle, and wind speed. 6 refs., 23 figs., 1 tab.

  15. Flow visualization study of the effect of injection hole geometry on an inclined jet in crossflow

    NASA Technical Reports Server (NTRS)

    Simon, F. F.; Ciancone, M. L.

    1985-01-01

    A flow visualization was studied by using neutrally buoyant, helium-filled soap bubbles, to determine the effect of injection hole geometry on the trajectory of an air jet in a crossflow and to investigate the mechanisms involved in jet deflection. Experimental variables were the blowing rate, and the injection hole geometry cusp facing upstream (CUS), cusp facing downstream (CDS), round, swirl passage, and oblong. It is indicated that jet deflection is governed by both the pressure drag forces and the entrainment of free-stream fluid into the jet flow. For injection hole geometries with similar cross-sectional areas and similar mass flow rates, the jet configuration with the larger aspect ratio experienced a greater deflection. Entrainment arises from lateral shearing forces on the sides of the jet, which set up a dual vortex motion within the jet and thereby cause some of the main-stream fluid momentum to be swept into the jet flow. This additional momentum forces the jet nearer the surface. Of the jet configurations, the oblong, CDS, and CUS configutations exhibited the largest deflections. The results correlate well with film cooling effectiveness data, which suggests a need to determine the jet exit configuration of optimum aspect ratio to provide maximum film cooling effectiveness.

  16. Flow visualization study of the effect of injection hole geometry on an inclined jet in crossflow

    NASA Technical Reports Server (NTRS)

    Simon, Frederick F.; Ciancone, Michael L.

    1987-01-01

    A flow visualization was studied by using neutrally buoyant, helium-filled soap bubbles, to determine the effect of injection hole geometry on the trajectory of an air jet in a crossflow and to investigate the mechanisms involved in jet deflection. Experimental variables were the blowing rate, and the injection hole geometry cusp facing upstream (CUS), cusp facing downstream (CDS), round, swirl passage, and oblong. It is indicated that jet deflection is governed by both the pressure drag forces and the entrainment of free-stream fluid into the jet flow. For injection hole geometries with similar cross-sectional areas and similar mass flow rates, the jet configuration with the larger aspect ratio experienced a greater deflection. Entrainment arises from lateral shearing forces on the sides of the jet, which set up a dual vortex motion within the jet and thereby cause some of the main-stream fluid momentum to be swept into the jet flow. This additional momentum forces the jet nearer the surface. Of the jet configurations, the oblong, CDS, and CUS configurations exhibited the largest deflections. The results correlate well with film cooling effectiveness data, which suggests a need to determine the jet exit configuration of optimum aspect ratio to provide maximum film cooling effectiveness.

  17. In-flight flow visualization characteristics of the NASA F-18 high alpha research vehicle at high angles of attack

    NASA Technical Reports Server (NTRS)

    Fisher, David F.; Delfrate, John H.; Richwine, David M.

    1991-01-01

    Surface and off-surface flow visualization techniques were used to visualize the 3-D separated flows on the NASA F-18 high alpha research vehicle at high angles of attack. Results near the alpha = 25 to 26 deg and alpha = 45 to 49 deg are presented. Both the forebody and leading edge extension (LEX) vortex cores and breakdown locations were visualized using smoke. Forebody and LEX vortex separation lines on the surface were defined using an emitted fluid technique. A laminar separation bubble was also detected on the nose cone using the emitted fluid technique and was similar to that observed in the wind tunnel test, but not as extensive. Regions of attached, separated, and vortical flow were noted on the wing and the leading edge flap using tufts and flow cones, and compared well with limited wind tunnel results.

  18. Direct visualization and quantitative analysis of water diffusion in complex biological tissues using CARS microscopy

    PubMed Central

    Yu, Ying-Chun; Sohma, Yoshiro; Takimoto, Shinichi; Miyauchi, Takayuki; Yasui, Masato

    2013-01-01

    To date, it has not been possible to measure microscopic diffusive water movements in epithelia and in the interstitial space of complex tissues and organs. Diffusive water movements are essential for life because they convey physiologically important small molecules, e.g. nutrients and signaling ligands throughout the extracellular space of complex tissues. Here we report the development of a novel method for the direct observation and quantitative analysis of water diffusion dynamics in a biologically organized tissue using Coherent Anti-Stokes Raman Scattering (CARS) microscopy. Using a computer simulation model to analyze the CARS O-H bond vibration data during H2O/D2O exchange in a 3D epithelial cyst, we succeeded in measuring the diffusive water permeability of the individual luminal and basolateral water pathways and also their response to hormonal stimulation. Our technique will be applicable to the measurement of diffusive water movements in other structurally complex and medically important tissues and organs. PMID:24067894

  19. Near infrared image processing to quantitate and visualize oxygen saturation during vascular occlusion.

    PubMed

    Jalil, B; Salvetti, O; Potì, L; Hartwig, V; Marinelli, M; L'Abbate, A

    2016-04-01

    The assessment of microcirculation spatial heterogeneity on the hand skin is the main objective of this work. Near-infrared spectroscopy based 2D imaging is a non-invasive technique for the assessment of tissue oxygenation. The haemoglobin oxygen saturation images were acquired by a dedicated camera (Kent Imaging) during baseline, ischaemia (brachial artery cuff occlusion) and reperfusion. Acquired images underwent a preliminary restoration process aimed at removing degradations occurring during signal capturing. Then, wavelet transform based multiscale analysis was applied to identify edges by detecting local maxima and minima across successive scales. Segmentation of test areas during different conditions was obtained by thresholding-based region growing approach. The method identifies the differences in microcirculatory control of blood flow in different regions of the hand skin. The obtained results demonstrate the potential use of NIRS images for the clinical evaluation of skin disease and microcirculatory dysfunction. PMID:26725781

  20. Computational Methods for Tracking, Quantitative Assessment, and Visualization of C. elegans Locomotory Behavior.

    PubMed

    Moy, Kyle; Li, Weiyu; Tran, Huu Phuoc; Simonis, Valerie; Story, Evan; Brandon, Christopher; Furst, Jacob; Raicu, Daniela; Kim, Hongkyun

    2015-01-01

    The nematode Caenorhabditis elegans provides a unique opportunity to interrogate the neural basis of behavior at single neuron resolution. In C. elegans, neural circuits that control behaviors can be formulated based on its complete neural connection map, and easily assessed by applying advanced genetic tools that allow for modulation in the activity of specific neurons. Importantly, C. elegans exhibits several elaborate behaviors that can be empirically quantified and analyzed, thus providing a means to assess the contribution of specific neural circuits to behavioral output. Particularly, locomotory behavior can be recorded and analyzed with computational and mathematical tools. Here, we describe a robust single worm-tracking system, which is based on the open-source Python programming language, and an analysis system, which implements path-related algorithms. Our tracking system was designed to accommodate worms that explore a large area with frequent turns and reversals at high speeds. As a proof of principle, we used our tracker to record the movements of wild-type animals that were freshly removed from abundant bacterial food, and determined how wild-type animals change locomotory behavior over a long period of time. Consistent with previous findings, we observed that wild-type animals show a transition from area-restricted local search to global search over time. Intriguingly, we found that wild-type animals initially exhibit short, random movements interrupted by infrequent long trajectories. This movement pattern often coincides with local/global search behavior, and visually resembles Lévy flight search, a search behavior conserved across species. Our mathematical analysis showed that while most of the animals exhibited Brownian walks, approximately 20% of the animals exhibited Lévy flights, indicating that C. elegans can use Lévy flights for efficient food search. In summary, our tracker and analysis software will help analyze the neural basis of the

  1. Computational Methods for Tracking, Quantitative Assessment, and Visualization of C. elegans Locomotory Behavior

    PubMed Central

    Moy, Kyle; Li, Weiyu; Tran, Huu Phuoc; Simonis, Valerie; Story, Evan; Brandon, Christopher; Furst, Jacob; Raicu, Daniela; Kim, Hongkyun

    2015-01-01

    The nematode Caenorhabditis elegans provides a unique opportunity to interrogate the neural basis of behavior at single neuron resolution. In C. elegans, neural circuits that control behaviors can be formulated based on its complete neural connection map, and easily assessed by applying advanced genetic tools that allow for modulation in the activity of specific neurons. Importantly, C. elegans exhibits several elaborate behaviors that can be empirically quantified and analyzed, thus providing a means to assess the contribution of specific neural circuits to behavioral output. Particularly, locomotory behavior can be recorded and analyzed with computational and mathematical tools. Here, we describe a robust single worm-tracking system, which is based on the open-source Python programming language, and an analysis system, which implements path-related algorithms. Our tracking system was designed to accommodate worms that explore a large area with frequent turns and reversals at high speeds. As a proof of principle, we used our tracker to record the movements of wild-type animals that were freshly removed from abundant bacterial food, and determined how wild-type animals change locomotory behavior over a long period of time. Consistent with previous findings, we observed that wild-type animals show a transition from area-restricted local search to global search over time. Intriguingly, we found that wild-type animals initially exhibit short, random movements interrupted by infrequent long trajectories. This movement pattern often coincides with local/global search behavior, and visually resembles Lévy flight search, a search behavior conserved across species. Our mathematical analysis showed that while most of the animals exhibited Brownian walks, approximately 20% of the animals exhibited Lévy flights, indicating that C. elegans can use Lévy flights for efficient food search. In summary, our tracker and analysis software will help analyze the neural basis of the

  2. Computational Methods for Tracking, Quantitative Assessment, and Visualization of C. elegans Locomotory Behavior.

    PubMed

    Moy, Kyle; Li, Weiyu; Tran, Huu Phuoc; Simonis, Valerie; Story, Evan; Brandon, Christopher; Furst, Jacob; Raicu, Daniela; Kim, Hongkyun

    2015-01-01

    The nematode Caenorhabditis elegans provides a unique opportunity to interrogate the neural basis of behavior at single neuron resolution. In C. elegans, neural circuits that control behaviors can be formulated based on its complete neural connection map, and easily assessed by applying advanced genetic tools that allow for modulation in the activity of specific neurons. Importantly, C. elegans exhibits several elaborate behaviors that can be empirically quantified and analyzed, thus providing a means to assess the contribution of specific neural circuits to behavioral output. Particularly, locomotory behavior can be recorded and analyzed with computational and mathematical tools. Here, we describe a robust single worm-tracking system, which is based on the open-source Python programming language, and an analysis system, which implements path-related algorithms. Our tracking system was designed to accommodate worms that explore a large area with frequent turns and reversals at high speeds. As a proof of principle, we used our tracker to record the movements of wild-type animals that were freshly removed from abundant bacterial food, and determined how wild-type animals change locomotory behavior over a long period of time. Consistent with previous findings, we observed that wild-type animals show a transition from area-restricted local search to global search over time. Intriguingly, we found that wild-type animals initially exhibit short, random movements interrupted by infrequent long trajectories. This movement pattern often coincides with local/global search behavior, and visually resembles Lévy flight search, a search behavior conserved across species. Our mathematical analysis showed that while most of the animals exhibited Brownian walks, approximately 20% of the animals exhibited Lévy flights, indicating that C. elegans can use Lévy flights for efficient food search. In summary, our tracker and analysis software will help analyze the neural basis of the

  3. Quantitative studies of chicken somatotrophs during growth and development by morphometry, immunocytochemistry, and flow cytometry.

    PubMed

    Malamed, S; Deaver, D; Perez, F; Radecki, S; Gibney, J; Scanes, C G

    1997-10-01

    Changes in the male chicken somatotroph during growth and maturation have been examined by morphometric and immunocytochemical (ICC) analysis of serial sections of the anterior pituitary gland and by flow cytometry of dispersed anterior pituitary cells. ICC showed that somatotrophs are confined to the middle and caudal thirds of the anterior pituitary gland at all ages from 5 to 26 weeks. At a given age somatotrophs are of equal size at all positions along the cephalocaudal axis of the anterior pituitary gland. However, there are age-related changes: from 5 to 11 weeks rises occur in both the mean total somatotroph volume per gland (64%) and the mean number of somatotrophs (78%), while the mean volume of the single somatotroph is unchanged. From 11 to 18 weeks the mean volume of the single somatotroph decreases 41%. From 18 to 26 weeks the mean volume of the somatotroph, the mean total somatotroph volume, and the mean number per gland do not change. Flow cytometry studies suggested that somatotrophs from adults have less growth hormone (GH) than somatotrophs from young birds. The increases in total somatotroph volume and number from 5 to 11 weeks are consistent with the rise in anterior pituitary GH reported previously. Basic quantitative morphological information about age-related changes in somatotrophs is reported here. When combined with additional facts from future work, they may explain the well-documented sharp decline in circulating GH from 5 to 11 weeks.

  4. Visualization of cavitating and flashing flows within a high aspect ratio injector

    NASA Astrophysics Data System (ADS)

    Thompson, Andrew S.

    Thermal management issues necessitate the use of fuel as a heat sink for gas turbine and liquid rocket engines. There are certain benefits to using heated fuels, namely, increased sensible enthalpy, increased combustion efficiency, a decrease in certain emissions, and enhanced vaporization characteristics. However, the thermal and pressure enviornment inside an injector can result in the fuel flashing to vapor. Depending on the injector design, this can have deleterious effects on engine performance. As interest in heated fuels inreases, it is important to understand what occurs in the flow path of an injector under flashing conditions. At the High Pressure Laboratory at Purdue University's Maurice J. Zucrow Laboritories, a test rig was designed and built to give visual access into the flow path of a 2-D slot injector. The rig is capable of pressurizing and heating a liquid to superheated conditions and utilizes a pneumatically actuated piston to pusth the liquid through the slot injector. Methanol was chosen as a surrogate fuel to allow for high levels of superheat at relatively low temperatures. Testing was completed with acrylic and quartz injectors of varying L/DH. Flashing conditions inside the injector flow path were induced via a combination of heating and back pressure adjustments. Volume flow rate, pressure measurements, and temperature measurements were made which allowed the discharge characteristics, the level of superheat, and other parameters to be calculated and compared. To give a basis for comparison the flashing results are compared to the flow through the injector under cavitating conditions. Cavitation and flashing appear to be related phenomena and this relationship is shown. Bubble formation under cavitating or flashing conditions is observed to attenuate the injector's discharge characteristics. High speed videos of the flow field were also collected. Several flow regimes and flow structures, unique to these regimes, were observed. A

  5. Flow visualization study of role of coherent structures in a tab wake

    NASA Astrophysics Data System (ADS)

    Elavarasan, R.; Meng, Hui

    2000-09-01

    A simple surface-mounted tapered tab has recently attracted fluids research both for its ability to enhance mixing and heat transfer (for which it is known as high-efficiency vortab mixer) and for its generation of coherent structures that are topologically similar to those found in natural turbulent boundary layers. Two types of structures, namely pressure-driven counter-rotating vortex pair (CVP) and hairpin vortices were previously identified in the tab wake, but the contribution of individual structures to the mixing enhancement process and how they interact are not known. In the present study, flow visualization using a planar laser-induced fluorescence (PLIF) technique is carried out to probe into the flow dynamics in the wake of the mixing tab. By injecting dye at an appropriate location and illuminating the flow in various planes, the structures are visualized clearly. The results show, in contrary to earlier observations, that the two types of structures dominate different regions. At the Reynolds number of 700 based on tab height ( h), the CVP has more influence in the region 0< x/ h<1.5. The counter-rotating action of the vortex pair induces a pumping action along the symmetry by which the low-speed fluid from the boundary layer is transported to the high-speed outer shear layer. The displaced fluid is entrained by the recirculating counter-rotating vortices and is mixed well while convecting downstream. Beyond this region, fully developed hairpin structures contribute more to mixing in a similar way as in a turbulent boundary layer. It is observed that the shedding frequency of hairpin vortices is slightly higher than the pumping frequency of the counter-rotating vortex pair. It is also observed that the hairpin structures loses their identity beyond x/ h>15, and there is no large-scale cross-stream mixing visible in this region.

  6. Application Of Micro-Highspeed Flow Visualization In Study Of Blood Cells Rheology In Vivo

    NASA Astrophysics Data System (ADS)

    Gui-shah, Li; Ni, Liang; Yu-ju, Lin; Jian, Zhang; Qiang, Wang

    1990-01-01

    A new experimental method has been developed in study of rheological behaviour of single red blood cell (RBC) in passing through the capillaries in vivo, using the technique of micro-highspeed cinecamera and micro-highspeed video system. It is one of the most important topics in the study of microcirculatory theories that fur-ther understand the deformability of RBC, flow states, velocities and dynamic mechanimi. A micro-highspeed flow visualization system consisted of essential elements: a biological microscope, a highspeed cinecmera with 35 mm film, a highspeed motion analysis system SP2000 (Kodak U.S.A) and a cold-light source etc. We have investigated the rheological parameters of single RBC in vivo in single capillaries which are about 3.3 to 6.9 um in diameters. The RBCs velocities are 0.1 to 0.25 mm/sec, and maximum shear stress on the outside surface of RBC is 13.8 dyn/cml, and maximum extension of RBC is 10.3 um. In aforementioned experiment, the highspeed flow visualization system frequency at 530 frames/sec and 200 frames/sec were used respectively. In addition, the vasomotion of precapillary sphincters have been measured and a complicated coupling phenomena between the RBC and sphincter have also been recorded and analysed. The experiment were performed with intravital hamsters and frogs. The results obtained by this system shown that the method designed by us are an effective tool in the study of rheological behaviour of single RBC in passing through the blood capillaries in vivoz.

  7. Flow visualization of the effect of pitch amplitude changes on the vortical signatures behind a three-dimensional flapping airfoil

    NASA Astrophysics Data System (ADS)

    Parker, Kamalluddien; von Ellenrieder, K. D.; Soria, J.

    2003-04-01

    The structure of the vortical flow behind a symmetrical airfoil of finite aspect ratio undergoing combinations of heave and pitch motions is investigated using qualitative dye flow visualization. The results are contrasted with flow visualizations obtained using electrolytic precipitation. The effect of changing the pitch amplitude is observed from the plan from view and wingtip view of the airfoil. With a Strouhal number of 0.35, Reyholds number based on airfoil chord of 164 and a phase angle of 90o, the maximum pitch amplitude is varied from 0° to 20°. The geometry of the downstream vortical flow is observed to change suggesting that the induced velocity from interacting structures decreases at lower pitch amplitudes. The rate of dynamic stall development may also be affected by variations in pitch amplitude since it appears that the timing of leading edge separation is affected. The flow field of an airfoil flapping periodically about a fixed axis appears to be influenced by the amplitude of pitching oscillations. At the tested Strouhal numbers the vortex formations appear to be primarily dependent on airfoil oscillation rather than heave translation. Furthermore, the results suggest that the wake structures originating from the dynamic stall process are important for the analysis of these complex flows. While the results from the two flow visualization techniques are similar, the dye flow visualization images provide greater qualitative insight. Inherently, precipitative techniques such as the one used here could provide good flow visualizations since the smoke/particles leave the surface of the airfoil, but the setup is found to be very sensitive to potential changes. The ion content in the electrolytic material was also found to play a role. Furthermore, the high ablation rate of the technique presented some practical problems.

  8. In-flight flow visualization results from the X-29A aircraft at high angles of attack

    NASA Technical Reports Server (NTRS)

    Delfrate, John H.; Saltzman, John A.

    1992-01-01

    Flow visualization techniques were used on the X-29A aircraft at high angles of attack to study the vortical flow off the forebody and the surface flow on the wing and tail. The forebody vortex system was studied because asymmetries in the vortex system were suspected of inducing uncommanded yawing moments at zero sideslip. Smoke enabled visualization of the vortex system and correlation of its orientation with flight yawing moment data. Good agreement was found between vortex system asymmetries and the occurrence of yawing moments. Surface flow on the forward-swept wing of the X-29A was studied using tufts and flow cones. As angle of attack increased, separated flow initiated at the root and spread outboard encompassing the full wing by 30 deg angle of attack. In general, the progression of the separated flow correlated well with subscale model lift data. Surface flow on the vertical tail was also studied using tufts and flow cones. As angle of attack increased, separated flow initiated at the root and spread upward. The area of separated flow on the vertical tail at angles of attack greater than 20 deg correlated well with the marked decrease in aircraft directional stability.

  9. A flow visualization study of single-arm sculling movement emulating cephalopod thrust generation

    NASA Astrophysics Data System (ADS)

    Kazakidi, Asimina; Gnanamanickam, Ebenezer P.; Tsakiris, Dimitris P.; Ekaterinaris, John A.

    2014-11-01

    In addition to jet propulsion, octopuses use arm-swimming motion as an effective means of generating bursts of thrust, for hunting, defense, or escape. The individual role of their arms, acting as thrust generators during this motion, is still under investigation, in view of an increasing robotic interest for alternative modes of propulsion, inspired by the octopus. Computational studies have revealed that thrust generation is associated with complex vortical flow patterns in the wake of the moving arm, however further experimental validation is required. Using the hydrogen bubble technique, we studied the flow disturbance around a single octopus-like robotic arm, undergoing two-stroke sculling movements in quiescent fluid. Although simplified, sculling profiles have been found to adequately capture the fundamental kinematics of the octopus arm-swimming behavior. In fact, variation of the sculling parameters alters considerably the generation of forward thrust. Flow visualization revealed the generation of complex vortical structures around both rigid and compliant arms. Increased disturbance was evident near the tip, particularly at the transitional phase between recovery and power strokes. These results are in good qualitative agreement with computational and robotic studies. Work funded by the ESF-GSRT HYDRO-ROB Project PE7(281).

  10. Functional gold nanoparticles coupled with microporous membranes: a flow controlled assay for colorimetric visualization of proteins.

    PubMed

    Chen, Yu-Yuan; Unnikrishnan, Binesh; Li, Yu-Jia; Huang, Chih-Ching

    2014-11-21

    We report a rapid and simple assay for colorimetric visualization of thrombin at nanomolar levels using functional gold nanoparticles (FAuNPs) coupled with microporous membranes. We used a 29-mer thiolated-thrombin-binding-aptamer (TBA29) to prepare TBA29 functionalized AuNPs (TBA29-AuNPs) for the selective detection of human thrombin. The sensing mechanism is based on the principle of TBA29-AuNPs flowing down through the nitrocellulose membrane (NCM) pores at different flow rates after binding to thrombin. Compared with free TBA29-AuNPs, when thrombin-TBA29-AuNPs were dropped on the NCM, the particles flowed down more easily through the NCM pores along with the buffer solution due to the increase in the gravity of particles. Therefore, color intensities of TBA29-AuNPs on the NCM depended on the concentration of thrombin; the color intensity was lighter when the concentration of thrombin was higher. Thrombin can be detected at the nanomolar level with the naked eye using this colorimetric probe. A protein G modified AuNP based probe (PG-AuNPs/NCM) was employed to detect human immunoglobulin G (hIgG) in plasma samples to demonstrate the practicality of our sensing system. Also, fibrinogen modified Au NPs were analyzed to demonstrate that this concept of detection could be extended to other proteins or systems, by functionalizing with suitable molecules.

  11. Distributed Data-Flow for In-Situ Visualization and Analysis at Petascale

    SciTech Connect

    Laney, D E; Childs, H R

    2009-03-13

    We conducted a feasibility study to research modifications to data-flow architectures to enable data-flow to be distributed across multiple machines automatically. Distributed data-flow is a crucial technology to ensure that tools like the VisIt visualization application can provide in-situ data analysis and post-processing for simulations on peta-scale machines. We modified a version of VisIt to study load-balancing trade-offs between light-weight kernel compute environments and dedicated post-processing cluster nodes. Our research focused on memory overheads for contouring operations, which involves variable amounts of generated geometry on each node and computation of normal vectors for all generated vertices. Each compute node independently decided whether to send data to dedicated post-processing nodes at each stage of pipeline execution, depending on available memory. We instrumented the code to allow user settable available memory amounts to test extremely low-overhead compute environments. We performed initial testing of this prototype distributed streaming framework, but did not have time to perform scaling studies at and beyond 1000 compute-nodes.

  12. Reconstruction and Visualization of Coordinated 3D Cell Migration Based on Optical Flow.

    PubMed

    Kappe, Christopher P; Schütz, Lucas; Gunther, Stefan; Hufnagel, Lars; Lemke, Steffen; Leitte, Heike

    2016-01-01

    Animal development is marked by the repeated reorganization of cells and cell populations, which ultimately determine form and shape of the growing organism. One of the central questions in developmental biology is to understand precisely how cells reorganize, as well as how and to what extent this reorganization is coordinated. While modern microscopes can record video data for every cell during animal development in 3D+t, analyzing these videos remains a major challenge: reconstruction of comprehensive cell tracks turned out to be very demanding especially with decreasing data quality and increasing cell densities. In this paper, we present an analysis pipeline for coordinated cellular motions in developing embryos based on the optical flow of a series of 3D images. We use numerical integration to reconstruct cellular long-term motions in the optical flow of the video, we take care of data validation, and we derive a LIC-based, dense flow visualization for the resulting pathlines. This approach allows us to handle low video quality such as noisy data or poorly separated cells, and it allows the biologists to get a comprehensive understanding of their data by capturing dynamic growth processes in stills. We validate our methods using three videos of growing fruit fly embryos.

  13. Visualization of Biosurfactant Film Flow in a Bacillus subtilis Swarm Colony on an Agar Plate.

    PubMed

    Kim, Kyunghoon; Kim, Jung Kyung

    2015-01-01

    Collective bacterial dynamics plays a crucial role in colony development. Although many research groups have studied the behavior of fluidic swarm colonies, the detailed mechanics of its motion remains elusive. Here, we developed a visualization method using submicron fluorescent beads for investigating the flow field in a thin layer of fluid that covers a Bacillus subtilis swarm colony growing on an agar plate. The beads were initially embedded in the agar plate and subsequently distributed spontaneously at the upper surface of the expanding colony. We conducted long-term live cell imaging of the B. subtilis colony using the fluorescent tracers, and obtained high-resolution velocity maps of microscale vortices in the swarm colony using particle image velocimetry. A distinct periodic fluctuation in the average speed and vorticity of flow in swarm colony was observed at the inner region of the colony, and correlated with the switch between bacterial swarming and growth phases. At the advancing edge of the colony, both the magnitudes of velocity and vorticity of flow in swarm colony were inversely correlated with the spreading speed of the swarm edge. The advanced imaging tool developed in this study would facilitate further understanding of the effect of micro vortices in swarm colony on the collective dynamics of bacteria. PMID:26343634

  14. Visualization of Biosurfactant Film Flow in a Bacillus subtilis Swarm Colony on an Agar Plate

    PubMed Central

    Kim, Kyunghoon; Kim, Jung Kyung

    2015-01-01

    Collective bacterial dynamics plays a crucial role in colony development. Although many research groups have studied the behavior of fluidic swarm colonies, the detailed mechanics of its motion remains elusive. Here, we developed a visualization method using submicron fluorescent beads for investigating the flow field in a thin layer of fluid that covers a Bacillus subtilis swarm colony growing on an agar plate. The beads were initially embedded in the agar plate and subsequently distributed spontaneously at the upper surface of the expanding colony. We conducted long-term live cell imaging of the B. subtilis colony using the fluorescent tracers, and obtained high-resolution velocity maps of microscale vortices in the swarm colony using particle image velocimetry. A distinct periodic fluctuation in the average speed and vorticity of flow in swarm colony was observed at the inner region of the colony, and correlated with the switch between bacterial swarming and growth phases. At the advancing edge of the colony, both the magnitudes of velocity and vorticity of flow in swarm colony were inversely correlated with the spreading speed of the swarm edge. The advanced imaging tool developed in this study would facilitate further understanding of the effect of micro vortices in swarm colony on the collective dynamics of bacteria. PMID:26343634

  15. Ergodic theory and experimental visualization of chaos in 3D flows

    NASA Astrophysics Data System (ADS)

    Sotiropoulos, Fotis; Mezic, Igor

    2000-11-01

    In his motivation for the ergodic hypothesis Gibbs invoked an analogy with fluid mixing: “…Yet no fact is more familiar to us than that stirring tends to bring a liquid to a state of uniform mixture, or uniform densities of its components…”. Although proof of the ergodic hypothesis is possible only for the simplest of systems using methods from ergodic theory, the use of the hypothesis has led to many accurate predictions in statistical mechanics. The problem of fluid mixing, however, turned out to be considerably more complicated than Gibbs envisioned. Chaotic advection can indeed lead to efficient mixing even in non-turbulent flows, but many non-mixed islands are known to persist within well-mixed regions. In numerical studies, Poincaré maps can be used to reveal the structure of such islands but their visualization in the laboratory requires laborious experimental procedures and is possible only for certain types of flows. Here we propose the first non-intrusive, simple to implement, and generally applicable technique for constructing experimental Poincaré maps and apply it to a steady, 3D, vortex breakdown bubble. We employ standard laser-induced fluorescence (LIF) and construct Poincaré maps by time averaging a sufficiently long sequence of instantaneous LIF images. We also show that ergodic theory methods provide a rigorous theoretical justification for this approach whose main objective is to reveal the non-ergodic regions of the flow.

  16. Flow Visualization and Unsteady Aerodynamics in the Flight of the Hawkmoth, Manduca sexta

    NASA Astrophysics Data System (ADS)

    Willmott, Alexander P.; Ellington, Charles P.; Thomas, Adrian L. R.

    1997-03-01

    The aerodynamic mechanisms employed during the flight of the hawkmoth, Manduca sexta, have been investigated through smoke visualization studies with tethered moths. Details of the flow around the wings and of the overall wake structure were recorded as stereophotographs and high-speed video sequences. The changes in flow which accompanied increases in flight speed from 0.4 to 5.7 m s-1 were analysed. The wake consists of an alternating series of horizontal and vertical vortex rings which are generated by successive down- and upstrokes, respectively. The downstroke produces significantly more lift than the upstroke due to a leading-edge vortex which is stabilized by a radial flow moving out towards the wingtip. The leading-edge vortex grew in size with increasing forward flight velocity. Such a phenomenon is proposed as a likely mechanism for lift enhancement in many insect groups. During supination, vorticity is shed from the leading edge as postulated in the 'flex' mechanism. This vorticity would enhance upstroke lift if it was recaptured during subsequent translation, but it is not. Instead the vorticity is left behind and the upstroke circulation builds up slowly. A small jet provides additional thrust as the trailing edges approach at the end of the upstroke. The stereophotographs also suggest that the bound circulation may not be reversed between half strokes at the fastest flight speeds.

  17. Flow visualization and unsteady aerodynamics in the flight of the hawkmoth, Manduca sexta

    PubMed Central

    Willmott, A. P.; Ellington, C. P.; Thomas, A. L. R.

    1997-01-01

    The aerodynamic mechanisms employed durng the flight of the hawkmoth, Manduca sexta, have been investigated through smoke visualization studies with tethered moths. Details of the flow around the wings and of the overall wake structure were recorded as stereophotographs and high-speed video sequences. The changes in flow which accompanied increases in flight speed from 0.4 to 5.7 m s-1 were analysed. The wake consists of an alternating series of horizontal and vertical vortex rings which are generated by successive down- and upstrokes, respectively. The downstroke produces significantly more lift than the upstroke due to a leading-edge vortex which is stabilized by a radia flow moving out towards the wingtip. The leading-edge vortex grew in size with increasing forward flight velocity. Such a phenomenon is proposed as a likely mechanism for lift enhancement in many insect groups. During supination, vorticity is shed from the leading edge as postulated in the 'flex' mechanism. This vorticity would enhance upstroke lift if it was recaptured diring subsequent translation, but it is not. Instead, the vorticity is left behind and the upstroke circulation builds up slowly. A small jet provides additional thrust as the trailing edges approach at the end of the upstroke. The stereophotographs also suggest that the bound circulation may not be reversed between half strokes at the fastest flight speeds.

  18. Quantitative analysis of arterial flow properties for detection of non-calcified plaques in ECG-gated coronary CT angiography

    NASA Astrophysics Data System (ADS)

    Wei, Jun; Zhou, Chuan; Chan, Heang-Ping; Chughtai, Aamer; Agarwal, Prachi; Kuriakose, Jean; Hadjiiski, Lubomir; Patel, Smita; Kazerooni, Ella

    2015-03-01

    We are developing a computer-aided detection system to assist radiologists in detection of non-calcified plaques (NCPs) in coronary CT angiograms (cCTA). In this study, we performed quantitative analysis of arterial flow properties in each vessel branch and extracted flow information to differentiate the presence and absence of stenosis in a vessel segment. Under rest conditions, blood flow in a single vessel branch was assumed to follow Poiseuille's law. For a uniform pressure distribution, two quantitative flow features, the normalized arterial compliance per unit length (Cu) and the normalized volumetric flow (Q) along the vessel centerline, were calculated based on the parabolic Poiseuille solution. The flow features were evaluated for a two-class classification task to differentiate NCP candidates obtained by prescreening as true NCPs and false positives (FPs) in cCTA. For evaluation, a data set of 83 cCTA scans was retrospectively collected from 83 patient files with IRB approval. A total of 118 NCPs were identified by experienced cardiothoracic radiologists. The correlation between the two flow features was 0.32. The discriminatory ability of the flow features evaluated as the area under the ROC curve (AUC) was 0.65 for Cu and 0.63 for Q in comparison with AUCs of 0.56-0.69 from our previous luminal features. With stepwise LDA feature selection, volumetric flow (Q) was selected in addition to three other luminal features. With FROC analysis, the test results indicated a reduction of the FP rates to 3.14, 1.98, and 1.32 FPs/scan at sensitivities of 90%, 80%, and 70%, respectively. The study indicated that quantitative blood flow analysis has the potential to provide useful features for the detection of NCPs in cCTA.

  19. TopoDrive and ParticleFlow--Two Computer Models for Simulation and Visualization of Ground-Water Flow and Transport of Fluid Particles in Two Dimensions

    USGS Publications Warehouse

    Hsieh, Paul A.

    2001-01-01

    This report serves as a user?s guide for two computer models: TopoDrive and ParticleFlow. These two-dimensional models are designed to simulate two ground-water processes: topography-driven flow and advective transport of fluid particles. To simulate topography-driven flow, the user may specify the shape of the water table, which bounds the top of the vertical flow section. To simulate transport of fluid particles, the model domain is a rectangle with overall flow from left to right. In both cases, the flow is under steady state, and the distribution of hydraulic conductivity may be specified by the user. The models compute hydraulic head, ground-water flow paths, and the movement of fluid particles. An interactive visual interface enables the user to easily and quickly explore model behavior, and thereby better understand ground-water flow processes. In this regard, TopoDrive and ParticleFlow are not intended to be comprehensive modeling tools, but are designed for modeling at the exploratory or conceptual level, for visual demonstration, and for educational purposes.

  20. Sensitive immunochemical approaches for quantitative (FPIA) and qualitative (lateral flow tests) determination of gentamicin in milk.

    PubMed

    Beloglazova, N V; Shmelin, P S; Eremin, S A

    2016-01-01

    Three kinds of immunoassays for the determination of gentamicin in milk samples were developed and validated. First, a fast and easily-performed fluorescence polarization immunoassay was used for characterization of the employed polyclonal antibody. The calculated Kaff were (1.9±0.4)×10(9)М(-1) and (6.0±0.2)×10(6)М(-1) for the high- and low-affinity fractions respectively. The assay was characterized with a good sensitivity, the limit of detection being 5μgkg(-1). Two different kinds of detection labels, i.e. colloidal gold (CG) and quantum dots (QDs), were evaluated for use in lateral-flow format with respect to rapid visual on-site testing. The cut-off levels for both qualitative formats were selected based on the maximum level for gentamicin in milk established by the European Commission, 100μgkg(-1), resulting in a 10μgkg(-1) cut-off considering sample dilution. The intra-laboratory validation was performed with sterilized milk samples artificially spiked with gentamicin at concentrations less than, equal to, and greater than the cut-off level. It was shown that milk products could be analyzed without any sample preparation, except for dilution with the buffer solution. The rates of false-positive and false-negative results were below 5% for both labels. The different developed immunoassays were tested towards gentamicin determination in artificially-spiked and naturally contaminated milk samples.