Science.gov

Sample records for moderator flow measurements

  1. MODERATELY STABLE FLOW OVER A THREE-DIMENSIONAL HILL - A COMPARISON OF LINEAR THEORY WITH LABORATORY MEASUREMENTS

    EPA Science Inventory

    Several series of experiments were performed in a stratified towing tank to study the near-field flow of a linearly stratified fluid over an isolated three-dimensional hill. he streamlines were obtained in the laboratory using a stereographic method to determine the paths of plum...

  2. Increase in Ultrasonic Intensity of Blood Speckle across Moderate Coronary Artery Stenosis Is an Independent Predictor of Functional Coronary Artery Stenosis Measured by Fractional Flow Reserve: Pilot Study

    PubMed Central

    Tanno, Jun; Nakano, Shintaro; Kasai, Takatoshi; Ako, Junya; Nakamura, Sunao; Senbonmatsu, Takaaki; Nishimura, Shigeyuki

    2015-01-01

    Background and Aims The degree of coronary artery stenosis should be assessed both anatomically and functionally. We observed that the intensity of blood speckle (IBS) on intravascular ultrasound (IVUS) is low proximal to a coronary artery stenosis, and high distal to the stenosis. We defined step-up IBS as the distal minus the proximal IBS, and speculated that this new parameter could be used for the functional evaluation of stenosis on IVUS. The aims of this study were to assess the relationships between step-up IBS and factors that affect coronary blood flow, and between step-up IBS and fractional flow reserve (FFR). Methods and Results This study enrolled 36 consecutive patients with angina who had a single moderate stenosis in the left anterior descending artery. All patients were evaluated by integrated backscatter IVUS and intracoronary pressure measurements. FFR was calculated from measurements using a coronary pressure wire during hyperemia. Conventional gray-scale IVUS images were recorded, and integrated backscatter was measured in three cross-sectional slices proximal and distal to the stenosis. Step-up IBS was calculated as (mean distal integrated backscatter value) − (mean proximal integrated backscatter value). Stepwise multiple linear regression analysis showed that the heart rate (r = 0.45, P = 0.005), ejection fraction (r = −0.39, P = 0.01), and hemoglobin level (r = −0.32, P = 0.04) were independently correlated with step-up IBS, whereas proximal and distal IBS were not associated with these factors. There was a strong inverse correlation between step-up IBS and FFR (r = −0.84, P < 0.001), which remained significant on stepwise multiple linear regression analysis. Conclusions The newly defined parameter of step-up IBS is potentially useful for the functional assessment of coronary artery stenosis. PMID:25607986

  3. Electrified film flows at moderate Reynolds number

    NASA Astrophysics Data System (ADS)

    Craster, Richard; Wray, Alex; Papageorgiou, Demetrios; Matar, Omar

    2014-11-01

    We examine the flow of a thin, inclined film sandwiched between two parallel electrodes. We follow the Weighted Residual Integral Boundary Layer method, which has been shown via comparison with both direct numerical simulations and experiments to give good results in both the drag-gravity and drag-inertia regimes. We extend existing models to give an accurate model of electrostatic effects via a similar separation of variables approach. A disparity in material properties between the liquid and gas regions induces a Maxwell stress at the interface, which affords a significant degree of control over the behaviour of the film. In one dimension, linear stability comparisons are made with a full Orr-Sommerfeld calculation, and nonlinear comparisons are made with direct numerical simulations, both showing excellent agreement in large parts of parameter space. The model is also extended to fully two-dimensional simulations. EPSRC Programme Grant, MEMPHIS, EP/K0039761/1, EPSRC DTG Studentship (AWW).

  4. Job characteristics, flow, and performance: the moderating role of conscientiousness.

    PubMed

    Demerouti, Evangelia

    2006-07-01

    The present article aims to show the importance of positive work-related experiences within occupational health psychology by examining the relationship between flow at work (i.e., absorption, work enjoyment, and intrinsic work motivation) and job performance. On the basis of the literature, it was hypothesized that (a) motivating job characteristics are positively related to flow at work and (b) conscientiousness moderates the relationship between flow and other ratings of (in-role and out-of-role) performance. The hypotheses were tested on a sample of 113 employees from several occupations. Results of moderated structural equation modeling analyses generally supported the hypotheses. Motivating job characteristics were predictive of flow, and flow predicted in-role and extra-role performance, for only conscientious employees. PMID:16834474

  5. Aerodynamic performance measurements at moderate Re

    NASA Astrophysics Data System (ADS)

    Rosen, M.; McArthur, J.; Spedding, G. R.

    2004-11-01

    There has been renewed interest in the aerodynamics of lifting wings at Reynolds numbers from 10^4 to 10^5, partly due to engineering requirements of small-scale, remotely piloted aircraft, and partly because birds and bats operate in this regime. Even when the wings do not flap or pitch or plunge, the flow over the small aspect ratio wings is likely to be three-dimensional and unsteady. Wind tunnel test results are described where force measurements are combined with DPIV studies. Some problems and principles of such measurement programs will also be discussed.

  6. MODFLOW 2. 0: A program for predicting moderator flow patterns

    SciTech Connect

    Peterson, P.F. . Dept. of Nuclear Engineering); Paik, I.K. )

    1991-07-01

    Sudden changes in the temperature of flowing liquids can result in transient buoyancy forces which strongly impact the flow hydrodynamics via flow stratification. These effects have been studied for the case of potential flow of stratified liquids to line sinks, but not for moderator flow in SRS reactors. Standard codes, such as TRAC and COMMIX, do not have the capability to capture the stratification effect, due to strong numerical diffusion which smears away the hot/cold fluid interface. A related problem with standard codes is the inability to track plumes injected into the liquid flow, again due to numerical diffusion. The combined effects of buoyant stratification and plume dispersion have been identified as being important in operation the Supplementary Safety System which injects neutron-poison ink into SRS reactors to provide safe shutdown in the event of safety rod failure. The MODFLOW code discussed here provides transient moderator flow pattern information with stratification effects, and tracks the location of ink plumes in the reactor. The code, written in Fortran, is compiled for Macintosh II computers, and includes subroutines for interactive control and graphical output. Removing the graphics capabilities, the code can also be compiled on other computers. With graphics, in addition to the capability to perform safety related computations, MODFLOW also provides an easy tool for becoming familiar with flow distributions in SRS reactors.

  7. Flow measuring structures

    NASA Astrophysics Data System (ADS)

    Boiten, W.

    1993-11-01

    The use of flow measuring structures is one of the various methods for the continuous measurement of discharges in open channels. In this report a brief summary of these methods is presented to get some insight in the selection of the most appropriate method. Then the distinct functions of water control structures are described. The flow measuring structures are classified according to international rules. The fields of application are dealt with and the definitions of weir flow are given. Much attention is paid to the aspects of how to select the most suitable flow measuring structure. The accuracy in the evaluation of the discharge has been related to the different error sources. A review of international standards on flow measuring structures concludes the report.

  8. Tomographic multiphase flow measurement.

    PubMed

    Sætre, C; Johansen, G A; Tjugum, S A

    2012-07-01

    Measurement of multiphase flow of gas, oil and water is not at all trivial and in spite of considerable achievements over the past two decades, important challenges remain (Corneliussen et al., 2005). These are related to reducing measurement uncertainties arising from variations in the flow regime, improving long term stability and developing new means for calibration, adjustment and verification of the multiphase flow meters. This work focuses on the first two issues using multi gamma beam (MGB) measurements for identification of the type of flow regime. Further gamma ray tomographic measurements are used for reference of the gas/liquid distribution. For the MGB method one Am-241 source with principal emission at 59.5 keV is used because this relatively low energy enables efficient collimation and thereby shaping of the beams, as well as compact detectors. One detector is placed diametrically opposite the source whereas the second is positioned to the side so that this beam is close to the pipe wall. The principle is then straight forward to compare the measured intensities of these detectors and through that identify the flow pattern, i.e. the instantaneous cross-sectional gas-liquid distribution. The measurement setup also includes Compton scattering measurements, which can provide information about the changes in the water salinity for flow segments with high water liquid ratio and low gas fractions. By measuring the transmitted intensity in short time slots (<100 ms), rapid regime variations are revealed. From this we can select the time sections suitable for salinity measurements. Since the salinity variations change at the time scale of hours, a running average can be performed to increase the accuracy of the measurements. Recent results of this work will be presented here. PMID:22341954

  9. Flow instabilities behind rotating bluff bodies for moderate Reynolds number

    NASA Astrophysics Data System (ADS)

    Goujon-Durand, Sophie; Gibi?Ski, Kornel; Skarysz, Maciej; Wesfreid, Jose Eduardo

    2015-11-01

    We present experiments to study the flow behind 3D bodies (spheres, disks and propellers) rotating about an axis aligned with the streamwise direction. The experiments has been performed in a water channel using LIF visualizations and PIV measurements. We study the flow evolution and the different flow regimes as a function of two control parameters: the Reynolds number Re and the dimensionless rotation or swirl rate Ω which is the ratio of the maximum azimuthal velocity of the body to the free stream velocity. In the present investigation, we covers the range of Re smaller than 400 and Ω from 0 to 4 in some cases. Different wakes regimes such as an axisymmetric base flow (or n-symmetric in the case of propellers), low frequency helicoidal states and higher frequency state are observed. The transitions between states are studied measuring the amplitude of the azimuthal modes components of the streamwise vorticity obtained by Fourier decomposition.

  10. Three-dimensional modeling of flow and deformation in idealized mild and moderate arterial vessels.

    PubMed

    Gu, Xi; Yeoh, Guan Heng; Timchenko, Victoria

    2016-10-01

    Three-dimensional numerical calculations of mild and moderate stenosed blood vessels have been performed. Large eddy simulation through a dynamic subgrid scale Smagorinsky model is applied to model the transitional and turbulent pulsatile flow. For the compliant stenosed model, fluid-structure interaction is realized through a two-way coupling between the fluid flow and the deforming vessel through the change in the external diameter due to the increment of circumferential pressure via a novel moving boundary approach. Model predictions compare very well against measured and numerical data for the centerline velocities, thickness of the flow separation zones and radial wall displacements. PMID:26863528

  11. Planetary heat flow measurements.

    PubMed

    Hagermann, Axel

    2005-12-15

    The year 2005 marks the 35th anniversary of the Apollo 13 mission, probably the most successful failure in the history of manned spaceflight. Naturally, Apollo 13's scientific payload is far less known than the spectacular accident and subsequent rescue of its crew. Among other instruments, it carried the first instrument designed to measure the flux of heat on a planetary body other than Earth. The year 2005 also should have marked the launch of the Japanese LUNAR-A mission, and ESA's Rosetta mission is slowly approaching comet Churyumov-Gerasimenko. Both missions carry penetrators to study the heat flow from their target bodies. What is so interesting about planetary heat flow? What can we learn from it and how do we measure it?Not only the Sun, but all planets in the Solar System are essentially heat engines. Various heat sources or heat reservoirs drive intrinsic and surface processes, causing 'dead balls of rock, ice or gas' to evolve dynamically over time, driving convection that powers tectonic processes and spawns magnetic fields. The heat flow constrains models of the thermal evolution of a planet and also its composition because it provides an upper limit for the bulk abundance of radioactive elements. On Earth, the global variation of heat flow also reflects the tectonic activity: heat flow increases towards the young ocean ridges, whereas it is rather low on the old continental shields. It is not surprising that surface heat flow measurements, or even estimates, where performed, contributed greatly to our understanding of what happens inside the planets. In this article, I will review the results and the methods used in past heat flow measurements and speculate on the targets and design of future experiments. PMID:16286290

  12. Flow Structure over Moderate Swept Delta Wing: Effects of Reynolds Number and Attack Angle

    NASA Astrophysics Data System (ADS)

    Ozturk, Ilhan; Zharfa, Mohammadreza; Yavuz, Mehmet Metin

    2013-11-01

    Recent investigations have revealed the appearance of a distinctive type of leading edge vortex, dual vortex structure, over simple delta wing planforms having moderate sweep angles. Flow over a moderate swept 45-degree wing has been investigated using laser illuminated smoke visualization, Laser Doppler Anemometry (LDA), and surface pressure measurements. The effects of Reynolds number and attack angles on dual vortex structure, vortex breakdown, and poststall regime are reported. The footprint of flow regimes on the surface of the planform is captured by the pressure measurements, and the lift performance of the wing is tried to be extracted. The relation between surface pressure fluctuations and near surface velocity fluctuations is investigated. The reattachment region of the separated shear layer on the surface, vortex breakdown, and stall regime are studied with considering the aforementioned relation, which will enlighten some of the aspects of the buffeting on the wing planform.

  13. Structural power flow measurement

    SciTech Connect

    Falter, K.J.; Keltie, R.F.

    1988-12-01

    Previous investigations of structural power flow through beam-like structures resulted in some unexplained anomalies in the calculated data. In order to develop structural power flow measurement as a viable technique for machine tool design, the causes of these anomalies needed to be found. Once found, techniques for eliminating the errors could be developed. Error sources were found in the experimental apparatus itself as well as in the instrumentation. Although flexural waves are the carriers of power in the experimental apparatus, at some frequencies longitudinal waves were excited which were picked up by the accelerometers and altered power measurements. Errors were found in the phase and gain response of the sensors and amplifiers used for measurement. A transfer function correction technique was employed to compensate for these instrumentation errors.

  14. Flow rate measuring devices for gas flows

    NASA Astrophysics Data System (ADS)

    Bonfig, K. W.

    1985-07-01

    Flowrate measuring devices are described: volume meter with fixed or mobile walls; turbine meter; throttling procedure; ultrasonic and Doppler methods; vortex method; rotary flowmeter; and swinging body flow measuring procedure. Flowrate can also be measured from the force exerted on bodies immersed in a fluid or based on thermodynamical principles. The characteristics and operating envelope of each device/method are given.

  15. Natural Laminar Flow Design for Wings with Moderate Sweep

    NASA Technical Reports Server (NTRS)

    Campbell, Richard L.; Lynde, Michelle N.

    2016-01-01

    A new method for the aerodynamic design of wings with natural laminar flow is under development at the NASA Langley Research Center. The approach involves the addition of new flow constraints to an existing knowledge-based design module for use with advanced flow solvers. The uniqueness of the new approach lies in the tailoring of target pressure distributions to achieve laminar flow on transonic wings with leading-edge sweeps and Reynolds numbers typical of current transports. The method is demonstrated on the Common Research Model configuration at critical N-factor levels representative of both flight and high-Reynolds number wind tunnel turbulence levels. The design results for the flight conditions matched the target extent of laminar flow very well. The design at wind tunnel conditions raised some design issues that prompted further improvements in the method, but overall has given promising results.

  16. Flow quality measurements in compressible subsonic flows

    NASA Technical Reports Server (NTRS)

    Stainback, P. Calvin; Johnson, Charles B.

    1987-01-01

    The purpose is to re-examine the heat transfer from a hot-wire probe in the compressible subsonic flow regime; describe the three-wire hot-wire probe calibration and data reduction techniques used to measure the velocity, density, and total temperature fluctuation; and present flow quality results obtained in the Langley 0.3 meter Transonic Cryogenic Wind Tunnel and in flight with the NASA JetStar from the same three-wire hot-wire probe.

  17. DNS and LES of Separated Flows at Moderate Reynolds Numbers

    NASA Astrophysics Data System (ADS)

    Cadieux, F.; Domaradzki, J. A.; Sayadi, T.; Bose, S.; Duchaine, F.

    2012-11-01

    Flows in rotating machinery, for unmanned and micro aerial vehicles, wind turbines, and propellers consist of different flow regimes. First, a laminar boundary layer is followed by a laminar separation bubble with a shear layer on top of it that experiences transition to turbulence. Subsequently, the separated turbulent flow reattaches and evolves downstream from a nonequilibrium turbulent boundary layer to an equilibrium one. Typical RANS and LES turbulence modeling methods experience difficulties when simulating such flows because they were developed for fully developed turbulent flows. This currently leaves DNS as the only reliable but computationally expensive alternative. Our work assesses the capability of LES to reduce the resolution requirements for such flows. Flow over a flat plate with suitable velocity boundary conditions away from the plate to produce a separation bubble is considered. Benchmark DNS data for this configuration was generated with the resolution of 50 ×106 mesh points; also used was a different DNS database with 15 ×106 points reported by Spalart and Strelets in JFM 403 (2000). Employing two codes, one using structured and another unstructured mesh, we concluded that accurate LES are possible using O(1%) of the DNS resolution. Work performed during Stanford-CTR Summer Program 2012.

  18. Endovascular blood flow measurement system

    NASA Astrophysics Data System (ADS)

    Khe, A. K.; Cherevko, A. A.; Chupakhin, A. P.; Krivoshapkin, A. L.; Orlov, K. Yu

    2016-06-01

    In this paper an endovascular measurement system used for intraoperative cerebral blood flow monitoring is described. The system is based on a Volcano ComboMap Pressure and Flow System extended with analogue-to-digital converter and PC laptop. A series of measurements performed in patients with cerebrovascular pathologies allows us to introduce “velocity-pressure” and “flow rate-energy flow rate” diagrams as important characteristics of the blood flow. The measurement system presented here can be used as an additional instrument in neurosurgery for assessment and monitoring of the operation procedure. Clinical data obtained with the system are used for construction of mathematical models and patient-specific simulations. The monitoring of the blood flow parameters during endovascular interventions was approved by the Ethics Committee at the Meshalkin Novosibirsk Research Institute of Circulation Pathology and included in certain surgical protocols for pre-, intra- and postoperative examinations.

  19. Invariant Measures for Cherry Flows

    NASA Astrophysics Data System (ADS)

    Saghin, Radu; Vargas, Edson

    2013-01-01

    We investigate the invariant probability measures for Cherry flows, i.e. flows on the two-torus which have a saddle, a source, and no other fixed points, closed orbits or homoclinic orbits. In the case when the saddle is dissipative or conservative we show that the only invariant probability measures are the Dirac measures at the two fixed points, and the Dirac measure at the saddle is the physical measure. In the other case we prove that there exists also an invariant probability measure supported on the quasi-minimal set, we discuss some situations when this other invariant measure is the physical measure, and conjecture that this is always the case. The main techniques used are the study of the integrability of the return time with respect to the invariant measure of the return map to a closed transversal to the flow, and the study of the close returns near the saddle.

  20. Measuring sap flow in plants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sap flow measurements provide a powerful tool for quantifying plant water use and monitoring qualitative physiological responses of plants to environmental conditions. As such, sap flow methods are widely employed to invesitgate the agronomic, ecological and hydrological outcomes of plant growth. T...

  1. Apparatus for measuring fluid flow

    DOEpatents

    Smith, J.E.; Thomas, D.G.

    Flow measuring apparatus includes a support loop having strain gages mounted thereon and a drag means which is attached to one end of the support loop and which bends the sides of the support loop and induces strains in the strain gages when a flow stream impacts thereon.

  2. Apparatus for measuring fluid flow

    DOEpatents

    Smith, Jack E.; Thomas, David G.

    1984-01-01

    Flow measuring apparatus includes a support loop having strain gages mounted thereon and a drag means which is attached to one end of the support loop and which bends the sides of the support loop and induces strains in the strain gages when a flow stream impacts thereon.

  3. "Influence Method" applied to measure a moderated neutron flux

    NASA Astrophysics Data System (ADS)

    Rios, I. J.; Mayer, R. E.

    2016-01-01

    The "Influence Method" is conceived for the absolute determination of a nuclear particle flux in the absence of known detector efficiency. This method exploits the influence of the presence of one detector, in the count rate of another detector when they are placed one behind the other and define statistical estimators for the absolute number of incident particles and for the efficiency. The method and its detailed mathematical description were recently published (Rios and Mayer, 2015 [1]). In this article we apply it to the measurement of the moderated neutron flux produced by an 241AmBe neutron source surrounded by a light water sphere, employing a pair of 3He detectors. For this purpose, the method is extended for its application where particles arriving at the detector obey a Poisson distribution and also, for the case when efficiency is not constant over the energy spectrum of interest. Experimental distributions and derived parameters are compared with theoretical predictions of the method and implications concerning the potential application to the absolute calibration of neutron sources are considered.

  4. Surface flow measurements from drones

    NASA Astrophysics Data System (ADS)

    Tauro, Flavia; Porfiri, Maurizio; Grimaldi, Salvatore

    2016-09-01

    Drones are transforming the way we sense and interact with the environment. However, despite their increased capabilities, the use of drones in geophysical sciences usually focuses on image acquisition for generating high-resolution maps. Motivated by the increasing demand for innovative and high performance geophysical observational methodologies, we posit the integration of drone technology and optical sensing toward a quantitative characterization of surface flow phenomena. We demonstrate that a recreational drone can be used to yield accurate surface flow maps of sub-meter water bodies. Specifically, drone's vibrations do not hinder surface flow observations, and velocity measurements are in agreement with traditional techniques. This first instance of quantitative water flow sensing from a flying drone paves the way to novel observations of the environment.

  5. MODFLOW 2.0: A program for predicting moderator flow patterns

    SciTech Connect

    Peterson, P.F.; Paik, I.K.

    1991-07-01

    Sudden changes in the temperature of flowing liquids can result in transient buoyancy forces which strongly impact the flow hydrodynamics via flow stratification. These effects have been studied for the case of potential flow of stratified liquids to line sinks, but not for moderator flow in SRS reactors. Standard codes, such as TRAC and COMMIX, do not have the capability to capture the stratification effect, due to strong numerical diffusion which smears away the hot/cold fluid interface. A related problem with standard codes is the inability to track plumes injected into the liquid flow, again due to numerical diffusion. The combined effects of buoyant stratification and plume dispersion have been identified as being important in operation the Supplementary Safety System which injects neutron-poison ink into SRS reactors to provide safe shutdown in the event of safety rod failure. The MODFLOW code discussed here provides transient moderator flow pattern information with stratification effects, and tracks the location of ink plumes in the reactor. The code, written in Fortran, is compiled for Macintosh II computers, and includes subroutines for interactive control and graphical output. Removing the graphics capabilities, the code can also be compiled on other computers. With graphics, in addition to the capability to perform safety related computations, MODFLOW also provides an easy tool for becoming familiar with flow distributions in SRS reactors.

  6. Code requirements document: MODFLOW 2.1: A program for predicting moderator flow patterns

    SciTech Connect

    Peterson, P.F.; Paik, I.K.

    1992-03-01

    Sudden changes in the temperature of flowing liquids can result in transient buoyancy forces which strongly impact the flow hydrodynamics via flow stratification. These effects have been studied for the case of potential flow of stratified liquids to line sinks, but not for moderator flow in SRS reactors. Standard codes, such as TRAC and COMMIX, do not have the capability to capture the stratification effect, due to strong numerical diffusion which smears away the hot/cold fluid interface. A related problem with standard codes is the inability to track plumes injected into the liquid flow, again due to numerical diffusion. The combined effects of buoyant stratification and plume dispersion have been identified as being important in operation of the Supplementary Safety System which injects neutron-poison ink into SRS reactors to provide safe shutdown in the event of safety rod failure. The MODFLOW code discussed here provides transient moderator flow pattern information with stratification effects, and tracks the location of ink plumes in the reactor. The code, written in Fortran, is compiled for Macintosh II computers, and includes subroutines for interactive control and graphical output. Removing the graphics capabilities, the code can also be compiled on other computers. With graphics, in addition to the capability to perform safety related computations, MODFLOW also provides an easy tool for becoming familiar with flow distributions in SRS reactors.

  7. Code requirements document: MODFLOW 2. 1: A program for predicting moderator flow patterns

    SciTech Connect

    Peterson, P.F. . Dept. of Nuclear Engineering); Paik, I.K. )

    1992-03-01

    Sudden changes in the temperature of flowing liquids can result in transient buoyancy forces which strongly impact the flow hydrodynamics via flow stratification. These effects have been studied for the case of potential flow of stratified liquids to line sinks, but not for moderator flow in SRS reactors. Standard codes, such as TRAC and COMMIX, do not have the capability to capture the stratification effect, due to strong numerical diffusion which smears away the hot/cold fluid interface. A related problem with standard codes is the inability to track plumes injected into the liquid flow, again due to numerical diffusion. The combined effects of buoyant stratification and plume dispersion have been identified as being important in operation of the Supplementary Safety System which injects neutron-poison ink into SRS reactors to provide safe shutdown in the event of safety rod failure. The MODFLOW code discussed here provides transient moderator flow pattern information with stratification effects, and tracks the location of ink plumes in the reactor. The code, written in Fortran, is compiled for Macintosh II computers, and includes subroutines for interactive control and graphical output. Removing the graphics capabilities, the code can also be compiled on other computers. With graphics, in addition to the capability to perform safety related computations, MODFLOW also provides an easy tool for becoming familiar with flow distributions in SRS reactors.

  8. Flood moderation: Declining peak flows along some Rocky Mountain rivers and the underlying mechanism

    NASA Astrophysics Data System (ADS)

    Rood, Stewart B.; Foster, Stephen G.; Hillman, Evan J.; Luek, Andreas; Zanewich, Karen P.

    2016-05-01

    It has been proposed that global warming will amplify the water cycle and intensify river floods. We tested this hypothesis by investigating historic trends in magnitudes, durations and timing of the annual peak flows of rivers that drain the Rocky Mountains around the North American hydrographic apex, the source for rivers flowing to the Pacific, Arctic (including Hudson Bay) and Atlantic Oceans. We sought century-long records and to reduce influences from land-use we assessed drainages from parks and protected areas. Of 30 rivers and reaches that were free-flowing or slightly regulated, seven displayed declining peak flows (7 p < 0.1, 4 p < 0.05), and one showed increase (p < 0.05); three of five moderately regulated rivers displayed decline (p < 0.05). Substantial floods, exceeding the 1-in-5 year recurrence (Q5), were more common in the early versus latter halves of the records for some Arctic drainages and were more common during the Pacific Decadal Oscillation negative phase for all regions. The timing of peak flows was relatively unchanged and Q5 flood durations declined for a few rivers. These results indicate flood moderation rather than flood intensification, particularly for Arctic Ocean drainages. This could reflect regional hydrological consequences from climate change including: (1) declining overall annual river flows; (2) winter warming that would increase the rain versus snow proportion, thus reducing snow accumulation and melt; and (3) spring warming that advances snow melt, lengthening the melt interval before peak flows. These changes would shift the seasonality of river flows and reduce annual peaks. We might expect continuing moderation of peak flows but there will probably still be occasional major floods from exceptional rain events such as occurred in northern Montana in 1964 and in southern Alberta in 2013.

  9. Measurement in multiphase reacting flows

    NASA Technical Reports Server (NTRS)

    Chigier, N. A.

    1979-01-01

    A survey is presented of diagnostic techniques and measurements made in multiphase reacting flows. The special problems encountered by the presence of liquid droplets, soot and solid particles in high temperature chemically reacting turbulent environments are outlined. The principal measurement techniques that have been tested in spray flames are spark photography, laser anemometry, thermocouples and suction probes. Spark photography provides measurement of drop size, drop size distribution, drop velocity, and angle of flight. Photographs are analysed automatically by image analysers. Photographic techniques are reliable, inexpensive and proved. Laser anemometers have been developed for simultaneous measurement of velocity and size of individual particles in sprays under conditions of vaporization and combustion. Particle/gas velocity differentials, particle Reynolds numbers, local drag coefficients and direct measurement of vaporization rates can be made by laser anemometry. Gas temperature in sprays is determined by direct in situ measurement of time constants immediately prior to measurement with compensation and signal analysis by micro-processors. Gas concentration is measured by suction probes and gas phase chromatography. Measurements of particle size, particle velocity, gas temperature, and gas concentration made in airblast and pressure atomised liquid spray flames are presented.

  10. Inertial and viscous forces on a rigid sphere in straining flows at moderate Reynolds numbers

    NASA Astrophysics Data System (ADS)

    Bagchi, Prosenjit; Balachandar, S.

    2003-04-01

    The focus of this paper is the effect of spatial non-uniformity in the ambient flow on the forces acting on a rigid sphere when the sphere Reynolds number, Re, is in the range 10 to 300. Direct numerical simulations (DNS) based on a pseudospectral methodology are carried out to solve for the unsteady three-dimensional flow field around a sphere which is either held stationary or allowed to translate freely under the hydrodynamic forces. The various components of the total force, namely the inertial, steady viscous, and history forces, are systematically estimated in the context of linearly varying straining flows. The inertial forces are isolated by computing the rapid changes in the drag and lift forces in response to a rapid acceleration of the ambient flow. It is shown that the inertial forces arising due to convective acceleration at moderate Reynolds numbers follow the inviscid flow result. While the effect of temporal acceleration depends only on the sign and magnitude of the acceleration, the effect of convective acceleration is shown to depend also on the initial state of the ambient flow. A simple theoretical argument is presented to support the numerical observations. It is also shown that the effect of convective acceleration on the steady viscous force can be realized on a slower time scale. The results show that the history kernels currently available in the literature are not adequate to represent the effect of non-uniformity on the history force.

  11. Gas flow meter and method for measuring gas flow rate

    DOEpatents

    Robertson, Eric P.

    2006-08-01

    A gas flow rate meter includes an upstream line and two chambers having substantially equal, fixed volumes. An adjustable valve may direct the gas flow through the upstream line to either of the two chambers. A pressure monitoring device may be configured to prompt valve adjustments, directing the gas flow to an alternate chamber each time a pre-set pressure in the upstream line is reached. A method of measuring the gas flow rate measures the time required for the pressure in the upstream line to reach the pre-set pressure. The volume of the chamber and upstream line are known and fixed, thus the time required for the increase in pressure may be used to determine the flow rate of the gas. Another method of measuring the gas flow rate uses two pressure measurements of a fixed volume, taken at different times, to determine the flow rate of the gas.

  12. Impeller flow field measurement and analysis

    NASA Technical Reports Server (NTRS)

    Fagan, J. R.; Fleeter, S.

    1991-01-01

    A series of experiments are performed to investigate and quantify the three-dimensional mean flow field in centrifugal compressor flow passages and to evaluate contemporary internal flow models. The experiments include the acquisition and analysis of LDV data in the impeller passages of a low-speed moderate-scale research mixed-flow centrifugal compressor operating at its design point. Predictions from a viscous internal flow model are then correlated with these data. The LDV data show the traditional jet-wake structure observed in many centrifugal compressors, with the wake observed along the shroud 70 percent of the length from the pressure to suction surface. The viscous model predicts the major flow phenomena. However, the correlations of the viscous predictions with the LDV data were poor.

  13. Variability of Sub-Canopy Flow, Temperature, and Horizontal Advection in Moderately Complex Terrain

    NASA Astrophysics Data System (ADS)

    Thomas, Christoph K.

    2011-04-01

    We examine the space-time structure of the wind and temperature fields, as well as that of the resulting spatial temperature gradients and horizontal advection of sensible heat, in the sub-canopy of a forest with a dense overstorey in moderately complex terrain. Data were collected from a sensor network consisting of ten stations and subject to orthogonal decomposition using the multiresolution basis set and stochastic analyses including two-point correlations, dimensional structure functions, and various other bulk measures for space and time variability. Despite some similarities, fundamental differences were found in the space-time structure of the motions dominating the variability of the sub-canopy wind and temperature fields. The dominating motions occupy similar spatial, but different temporal, scales. A conceptual space-time diagram was constructed based on the stochastic analysis that includes the important end members of the spatial and temporal scales of the observed motions of both variables. Short-lived and small-scale motions govern the variability of the wind, while the diurnal temperature oscillation driven by the surface radiative transfer is the main determinant of the variability in the temperature signal, which occupies much larger time scales. This scale mismatch renders Taylor's hypothesis for sub-canopy flow invalid and aggravates the computation of meaningful estimates of horizontal advective fluxes without dense spatial information. It may further explain the ambiguous and inconclusive results reported in numerous energy and mass balance and advection studies evaluating the hypothesis that accounting for budget components other than the change in storage term and the vertical turbulent flux improves the budget closure when turbulent diffusion is suppressed in plant canopies. Estimates of spatial temperature gradients and advective fluxes were sensitive to the network geometry and the spatial interpolation method. The assumption of linear

  14. Method and device for measuring fluid flow

    DOEpatents

    Atherton, Richard; Marinkovich, Phillip S.; Spadaro, Peter R.; Stout, J. Wilson

    1976-11-23

    This invention is a fluid flow measuring device for determining the coolant flow at the entrance to a specific nuclear reactor fuel region. The device comprises a plurality of venturis having the upstream inlet and throat pressure of each respectively manifolded together to provide one static pressure signal for each region monitored. The device provides accurate flow measurement with low pressure losses and uniform entrance and discharge flow distribution.

  15. Laminar flow past a spinning bullet-shaped body at moderate angular velocities

    NASA Astrophysics Data System (ADS)

    Jiménez-González, J. I.; Sanmiguel-Rojas, E.; Sevilla, A.; Martínez-Bazán, C.

    2013-11-01

    We present a numerical study of the flow past a spinning bullet-shaped body of length-to-diameter ratio L/D=2, focusing on the evolution of the forces and flow regimes that appear depending on the values of the two governing parameters, namely the Reynolds number, Re=ρw∞D/μ, and the dimensionless angular velocity, Ω=ωD/(2w∞), where ρ, μ and w∞ are the free-stream density, viscosity and velocity, respectively, and ω is the angular velocity of the body. The parametric study covers the range 0≤Ω≤0.4 for Re<450, corresponding to laminar flow and moderate rotation velocities. It is shown that the (Re,Ω) parameter plane can be divided into four regions, corresponding to the destabilization of several instability modes. In the range 0≤Ω≲0.2, three different flow regimes take place as Re increases keeping constant Ω: axisymmetric, frozen and spiral flow regimes respectively; the latter leading to a swirling configuration of vortices curling up around the axis, caused by a combination of the frozen mode and the vortex shedding. However, at Ω≃0.2, a new frozen spiral mode takes place for large enough values of Re, where two counter-rotating vortices spiral around the axis, as a result of a lock-in process of the vortex shedding associated to the unsteady spiral regime, being this mode the single unstable one existent for Ω≥0.225. An exhaustive study of the dependence of the drag and lift forces on Ω and Re is also presented.

  16. Measurement of cryogenic moderator temperature effects in a small heterogeneous thermal reactor

    SciTech Connect

    Hoovler, G.S.; Ball, R.M.; Lewis, R.H.

    1994-12-31

    Past papers have described a critical experiment (CX) built at Sandia National Laboratories to investigate the neutronic behavior of the particle-bed reactor (PBK). Among the experiments previously reported were tests to measure the reactivity effect of uniform temperature variations between 20 and 80{degree}C. This paper describes additional experiments designed to examine the effects of cryogenic moderator temperatures on core reactivity and neutron spectrum. The general importance of temperature effects to the design of the PBR have been previously discussed. A unique feature of the PBR is that the moderator may be at cryogenic temperatures during reactor startup. Because temperature effects in small, heterogeneous thermal reactors can be significant and because we found no integral measurements with cryogenic moderators in such systems, an experiment with a cryogenic moderator was designed and performed in the CX as an extension to the isothermal measurements previously reported.

  17. IR multiphoton absorption of SF6 in flow with Ar at moderate energy fluences

    NASA Astrophysics Data System (ADS)

    Makarov, G. N.; Ronander, E.; van Heerden, S. P.; Gouws, M.; van der Merwe, K.

    1997-10-01

    IR multiple photon absorption (MPA) of SF6 in flow with Ar (SF6: Ar=1:100) in conditions of a large vibrational/rotational temperature difference (TV𪒮 K, TR䏐 K) was studied at moderate energy fluences from ۂ.1 to 𪐬 mJ/cm2, which are of interest for isotope selective two-step dissociation of molecules. A 50 cm Laval-type slit nozzle for the flow cooling, and a TEA CO2-laser for excitation of molecules were used in the experiments. The laser energy fluence dependences of the SF6 MPA were studied for several CO2-laser lines which are in a good resonance with the linear absorption spectrum of the Ƚ vibration of SF6 at low temperature. The effect of the laser pulse duration (intensity) on MPA of flow cooled SF6 with Ar was also studied. The results are compared with those obtained in earlier studies.

  18. LEFT VENTRICULAR DYSSYNCHRONY IN PATIENTS WITH MODERATE CORONARY STENOSIS AND BORDER LINE FRACTIONAL FLOW RESERVE

    PubMed Central

    SHIBATA, YOHEI; SONE, TAKAHITO; TSUBOI, HIDEYUKI; ISOBE, SATOSHI; ISHII, HIDEKI; SUZUKI, SUSUMU; HAYASHI, MUTSUHARU; MUROHARA, TOYOAKI

    2015-01-01

    ABSTRACT The cutoff values of fractional flow reserve (FFR) to detect physiological myocardial ischemia are still controversial. Some studies have reported that left ventricular (LV) dyssynchrony occurs in patients with coronary artery disease (CAD). The purpose of this study was to investigate LV dyssynchrony in patients with moderate coronary stenosis and borderline FFR, using stress electrocardiographically-gated myocardial perfusion single-photon emission computed tomography (SPECT). The study population comprised 10 patients with moderate (50–75% diameter) stenosis and an FFR in the range 0.75–0.90, who were compared to 10 control subjects. All underwent stress myocardial 99mTc-sestamibi (MIBI) or tetrofosmin SPECT imaging. The regional time to end systole (TES), time to peak ejection (TPE), and time to peak filling (TPF) were obtained as indexes of perfusion and function, using gated SPECT (pFAST) in combination with Cardio Gated SPECT Regional Assessment for LV Function (cardioGRAF). The dyssynchrony index (DI) was also calculated. The DI of post-stress TES was significantly greater than that of rest in patients with moderate CAD (4.8 ± 2.8 vs. 2.7 ± 1.5, P = 0.01), but there were no significant differences in the control subjects (3.0 ± 1.7 vs. 2.9 ± 1.9, P = 0.99). There were no significant differences in TPE and TPF between the groups. In conclusion, LV dyssynchrony may occur after stress in patients with coronary stenosis and borderline FFR, even without a significant reduction in perfusion. PMID:25797980

  19. Left ventricular dyssynchrony in patients with moderate coronary stenosis and border line fractional flow reserve.

    PubMed

    Shibata, Yohei; Sone, Takahito; Tsuboi, Hideyuki; Isobe, Satoshi; Ishii, Hideki; Suzuki, Susumu; Hayashi, Mutsuharu; Murohara, Toyoaki

    2015-02-01

    The cutoff values of fractional flow reserve (FFR) to detect physiological myocardial ischemia are still controversial. Some studies have reported that left ventricular (LV) dyssynchrony occurs in patients with coronary artery disease (CAD). The purpose of this study was to investigate LV dyssynchrony in patients with moderate coronary stenosis and borderline FFR, using stress electrocardiographically-gated myocardial perfusion single-photon emission computed tomography (SPECT). The study population comprised 10 patients with moderate (50-75% diameter) stenosis and an FFR in the range 0.75-0.90, who were compared to 10 control subjects. All underwent stress myocardial (99m)Tc-sestamibi (MIBI) or tetrofosmin SPECT imaging. The regional time to end systole (TES), time to peak ejection (TPE), and time to peak filling (TPF) were obtained as indexes of perfusion and function, using gated SPECT (pFAST) in combination with Cardio Gated SPECT Regional Assessment for LV Function (cardioGRAF). The dyssynchrony index (DI) was also calculated. The DI of post-stress TES was significantly greater than that of rest in patients with moderate CAD (4.8 ± 2.8 vs. 2.7 ± 1.5, P = 0.01), but there were no significant differences in the control subjects (3.0 ± 1.7 vs. 2.9 ± 1.9, P = 0.99). There were no significant differences in TPE and TPF between the groups. In conclusion, LV dyssynchrony may occur after stress in patients with coronary stenosis and borderline FFR, even without a significant reduction in perfusion. PMID:25797980

  20. Increase in the Late Diastolic Filling Force is Associated With Impaired Transmitral Flow Efficiency in Acute Moderate Elevation of Left Ventricular Afterload

    PubMed Central

    Jiamsripong, Panupong; Calleja, Anna M.; Alharthi, Mohsen S.; Cho, Eun Joo; McMahon, Eileen M.; Heys, Jeffrey J.; Milano, Michele; Sengupta, Partho P.; Khandheria, Bijoy K.; Belohlavek, Marek

    2009-01-01

    Aims Analysis of intraventricular flow force and efficiency is a novel concept of quantitatively assessing left ventricular (LV) hemodynamic performance. We have parametrically characterized diastolic filling flow by early inflow force (EIF), late inflow force (LIF), and total inflow force (TIF) and by vortex formation time (VFT), a fundamental parameter of fluid transport efficiency. The purpose was to determine what changes in inflow forces characterize a decrease in diastolic blood transport efficiency in acute moderate elevation of LV afterload. Methods and Results In 8 open-chest pigs, the flow force and VFT parameters were calculated from conventional and flow Doppler echocardiography measurements at baseline and during brief (3-minute) moderate elevation in afterload induced by increasing systolic blood pressure to 130% of baseline value. Systolic LV function decreased significantly during elevated afterload. EIF did not significantly change, whereas LIF increased from 5,822.09 ± 1,656.50 to 13,948.25 ± 9,773.96 dyn (P = 0.0490) and TIF increased from 13,783.35 ± 4,816.58 to 21,836.67 ± 8,635.33 dyn (P = 0.0310). VFT decreased from 4.09 ± 0.29 to 2.79 ± 1.10 (P = 0.0068), confirming suboptimal flow transport efficiency. Conclusions Even a brief moderate increase of LV afterload causes a significant increase in the late diastolic filling force and impairs transmitral flow efficiency. PMID:19168767

  1. Measuring and metering of unsteady flows

    SciTech Connect

    Padmanabhan, M.; Dodge, F.T.; Heidrick, T.R.

    1986-01-01

    This book presents the papers given at a conference on unsteady flow. Topics considered at the conference included the identification of pulsation induced orifice metering errors including gage line shift, electromagnetic flowmeters, mass flow measurements on the flue of a woodburning stove, fluid excitation forces acting on a tube array, and a numerical analysis of pulsating laminar flow through a pipe orifice.

  2. On the Methods to Measure Powder Flow.

    PubMed

    Tan, Geoffrey; Morton, David A V; Larson, Ian

    2015-01-01

    The flow of powders can often play a critical role in the manufacturing of pharmaceutical products. Many of these processes require good, consistent and predictable flow of powders to ensure continuous production of pharmaceutical dosages and to ensure their quality. Therefore, the flow of powders is of paramount importance to the pharmaceutical industry and thus the measuring and evaluating of powder flow is of utmost importance. At present, there are numerous methods in which the flow of powders can be measured. However, due to the complex and environment-dependent nature of powders, no one method exists that is capable of providing a complete picture of the behaviour of powders under dynamic conditions. Some of the most commonly applied methods to measure the flow of powders include: density indices, such as the Carr index and Hausner ratio, powder avalanching, the angle of repose (AOR), flow through an orifice, powder rheometry and shear cell testing. PMID:26446467

  3. Sound speed in downhole flow measurement.

    PubMed

    Ünalmis, Ö Haldun

    2016-07-01

    This paper describes the use of sound speed in flow measurement applications in the high-pressure/high-temperature downhole environment. The propagation speed of a sound wave is a powerful tool to extract useful information from a flowing fluid medium in pipe whether the medium consists of a single-phase or multiphase flow. Considering the complex nature of the flow patterns and changing phase fractions from reservoir to surface, utilizing the propagation speed of sound of a fluid mixture is not a trivial task, especially if the interest is real-time flow measurement. The demanding applications span a wide spectrum from noisy medium originating from fast-moving gas/liquid flows to quiet medium originating from slow-moving liquid/liquid flows. In the current work, multiple flow loop tests are conducted in different facilities to evaluate the direct use of sound speed in flow rate measurement and the results are associated with real-life field examples. A tool analysis map is developed that addresses the use of sound speed for flow measurement under different scenarios. Although most examples are based on strain-based local sensing of the flow, the use of sound speed is independent of the methodology and can be implemented by other methods such as acoustic-based distributed sensing. PMID:27475167

  4. Effects of microstructure on flow properties of fibrous porous media at moderate Reynolds number

    NASA Astrophysics Data System (ADS)

    Tamayol, A.; Wong, K. W.; Bahrami, M.

    2012-02-01

    In this study, effects of microstructure on the viscous permeability and Forchheimer coefficient of monodispersed fibers are investigated. The porous material is represented by a unit cell which is assumed to be repeated throughout the medium. Based on the orientation of the fibers in the space, fibrous media are divided into three categories: one-, two-, and three-directional (1D, 2D, and 3D) structures. Parallel and transverse flow through square arrangements of 1D fibers, simple 2D mats, and 3D simple cubic structures are solved numerically over a wide range of porosity (0.35 < ɛ < 0.95) and Reynolds number (0.01 < Re < 200). The results are used to calculate the permeability and the inertial coefficient of the considered geometries. An experimental study is performed; the flow coefficients of three different ordered tube banks in the moderate range of Reynolds number (0.001 < Re < 15) are determined. The numerical results are successfully compared with the present and the existing experimental data in the literature. The results suggest that the permeability and Forchheimer coefficient are functions of porosity and fiber orientation. A comparison of the experimental and numerical results with the Ergun equation reveals that this equation is not suitable for highly porous materials. As such, accurate correlations are proposed for determining the Forchheimer coefficient in fibrous porous media.

  5. Thermoelectric Magnetohydrodynamic Flow During Crystal Growth with a Moderate or Weak Magnetic Field

    NASA Technical Reports Server (NTRS)

    Khine, Y. Y.; Walker, John S.; Szofran, Frank R.; Rose, M. Franklin (Technical Monitor)

    2000-01-01

    This paper treats a steady, axisymmetric melt motion in a cylindrical ampoule with a uniform, axial magnetic field and with an electric current due to a radial temperature variation along the crystal-melt interface, where the values of the absolute thermoelectric power for the crystal and melt are different. The radial component of the thermoelectric current in the melt produces an azimuthal body force, and the axial variation of the centrifugal force due to the azimuthal motion drives a meridional circulation with radial and axial velocities. For moderate magnetic field strengths, the azimuthal velocity and magnetic field produce a radial induced electric field which partially cancels the Seebeck electromotive force in the melt, so that the thermoelectric current and the melt motion are coupled. For weak magnetic fields, the thermoelectric current is decoupled from the melt motion, which is an ordinary hydrodynamic flow driven by a known azimuthal body force. The results show how the flow varies with the strength of the magnetic field and with the magnitude of the temperature variation along the crystal-melt interface. They also define the parameter ranges for which the simpler weak-field decoupled analysis gives accurate predictions.

  6. Measuring Your Peak Flow Rate

    MedlinePlus

    ... meter. Proper cleaning with mild detergent in hot water will keep your peak flow meter working accurately and may keep you healthier. Related Content News: American Lung Association Applauds EPA’s Update to Cross-State Air Pollution Rule News: American Lung Association Invests More Than $ ...

  7. Measurement of Diffusion in Flowing Complex Fluids

    PubMed Central

    Leonard, Edward F.; Aucoin, Christian P.; Nanne, Edgar E.

    2006-01-01

    A microfluidic device for the measurement of solute diffusion as well as particle diffusion and migration in flowing complex fluids is described. The device is particularly suited to obtaining diffusivities in such fluids, which require a desired flow state to be maintained during measurement. A method based on the Loschmidt diffusion theory and short times of exposure is presented to allow calculation of diffusivities from concentration differences in the flow streams leaving the cell. PMID:18560469

  8. Instrument continuously measures density of flowing fluids

    NASA Technical Reports Server (NTRS)

    Jacobs, R. B.; Macinko, J.; Miller, C. E.

    1967-01-01

    Electromechanical densitometer continuously measures the densities of either single-phase or two-phase flowing cryogenic fluids. Measurement is made on actual flow. The instrument operates on the principle that the mass of any vibrating system is a primary factor in determining the dynamic characteristics of the system.

  9. Improved Ultrasonic Transducer For Measuring Cryogenic Flow

    NASA Technical Reports Server (NTRS)

    Barkhoudarian, Sarkis

    1991-01-01

    Improved ultrasonic transducer used to measure flow of cryogenic fluid. Includes wedge made nonintrusive by machining it out of bulk material of duct carrying fluid. Skewed surfaces of wedge suppress standing waves, thus reducing ringing and increasing signal-to-noise ratio. Increases accuracy of measurements of times of arrival of ultrasonic pulses, from which times flow inferred.

  10. Helium-flow measurement using ultrasonic technique

    NASA Astrophysics Data System (ADS)

    Sondericker, J. H.

    1983-08-01

    The ideal cryogenic instrumentation for the colliding beam accelerator helium distribution system does not add pressure drop to the system, functions over the entire temperature range, has high resolution, and delivers accurate mass flow measurement data. The design and testing of an ultrasonic flowmeter which measures helium flow under different temperatures are described.

  11. COTS MEMS Flow-Measurement Probes

    NASA Technical Reports Server (NTRS)

    Redding, Chip; Smith, Floyd A.; Blank, Greg; Cruzan, Charles

    2004-01-01

    As an alternative to conventional tubing instrumentation for measuring airflow, designers and technicians at Glenn Research Center have been fabricating packaging components and assembling a set of unique probes that contain commercial off-the-shelf (COTS) microelectromechanical systems (MEMS) sensor chips. MEMS sensor chips offer some compelling advantages over standard macroscopic measurement devices. MEMS sensor technology has matured through mass production and use in the automotive and aircraft industries. At present, MEMS are the devices of choice for sensors in such applications as tire-pressure monitors, altimeters, pneumatic controls, cable leak detectors, and consumer appliances. Compactness, minimality of power demand, rugged construction, and moderate cost all contribute to making MEMS sensors attractive for instrumentation for future research. Conventional macroscopic flow-measurement instrumentation includes tubes buried beneath the aerodynamic surfaces of wind-tunnel models or in wind-tunnel walls. Pressure is introduced at the opening of each such tube. The pressure must then travel along the tube before reaching a transducer that generates an electronic signal. The lengths of such tubes typically range from 20 ft (approx.= 6 m) to hundreds of feet (of the order of 100 m). The propagation of pressure signals in the tubes damps the signals considerably and makes it necessary to delay measurements until after test rigs have reached steady-state operation. In contrast, a MEMS pressure sensor that generates electronic output can take readings continuously under dynamic conditions in nearly real time. In order to use stainless-steel tubing for pressure measurements, it is necessary to clean many tubes, cut them to length, carefully install them, delicately deburr them, and splice them. A cluster of a few hundred 1/16-in.- (approx.=1.6-mm-) diameter tubes (such clusters are common in research testing facilities) can be several inches (of the order of 10

  12. Direct numerical simulation of moderate-Reynolds-number flow past arrays of rotating spheres

    NASA Astrophysics Data System (ADS)

    Zhou, Qiang; Fan, Liang-Shih

    2015-07-01

    Direct numerical simulations with an immersed boundary-lattice Boltzmann method are used to investigate the effects of particle rotation on flows past random arrays of mono-disperse spheres at moderate particle Reynolds numbers. This study is an extension of a previous study of the authors [Q. Zhou and L.-S. Fan, "Direct numerical simulation of low-Reynolds-number flow past arrays of rotating spheres," J. Fluid Mech. 765, 396-423 (2015)] that explored the effects of particle rotation at low particle Reynolds numbers. The results of this study indicate that as the particle Reynolds number increases, the normalized Magnus lift force decreases rapidly when the particle Reynolds number is in the range lower than 50. For the particle Reynolds number greater than 50, the normalized Magnus lift force approaches a constant value that is invariant with solid volume fractions. The proportional dependence of the Magnus lift force on the rotational Reynolds number (based on the angular velocity and the diameter of the spheres) observed at low particle Reynolds numbers does not change in the present study, making the Magnus lift force another possible factor that can significantly affect the overall dynamics of fluid-particle flows other than the drag force. Moreover, it is found that both the normalized drag force and the normalized torque increase with the increase of the particle Reynolds number and the solid volume fraction. Finally, correlations for the drag force, the Magnus lift force, and the torque in random arrays of rotating spheres at arbitrary solids volume fractions, rotational Reynolds numbers, and particle Reynolds numbers are formulated.

  13. Laser Doppler velocity measurements of swirling flows with upstream influence

    NASA Technical Reports Server (NTRS)

    Rloff, K. L.; Bossel, H. H.

    1973-01-01

    Swirling flow in a rotating tube is studied by flow visualization at a moderate Reynolds number, and its velocity field is measured by laser-Doppler anemometry. The tube has constant diameter, and approximately uniform initial rigid rotation of the flow is assured by passing the flow through a rotating plug of porous metal before it enters the test section. At moderate swirl values, an object mounted on the tube centerline causes a closed bubble to form upstream of the obstacle, with a clearly defined stagnation point on the axis, and recirculating flow inside the bubble. The bubble length grows upstream as the swirl is increased, until it breaks up into a Taylor column reaching all the way upstream and downstream at swirl values above a certain critical value. A vortex jump (in the sense of Benjamin) occurs downstream of the obstacle except when the Taylor column is present. Using a laser-Doppler anemometer, axial and swirl velocity profiles are obtained at several stations upstream and downstream of the bubble, and in and around the bubble.

  14. Achromatic Emission Velocity Measurements in Luminous Flows

    NASA Technical Reports Server (NTRS)

    Schneider, S. J.; Fulghum, S. F.; Rostler, P. S.

    1997-01-01

    A new velocity measurement instrument for luminous flows was developed by Science Research Laboratory for NASA. The SIEVE (Segmented Image Emission VElocimeter) instrument uses broadband light emitted by the flow for the velocity measurement. This differs from other velocimetry techniques in that it does not depend on laser illumination and/or light scattering from particles in the flow. The SIEVE is a passive, non-intrusive diagnostic. By moving and adjusting the imaging optics, the SIEVE can provide three-dimensional mapping of a flow field and determine turbulence scale size. A SIEVE instrument was demonstrated on an illuminated rotating disk to evaluate instrument response and noise and on an oxy-acetylene torch to measure flame velocities. The luminous flow in rocket combustors and plumes is an ideal subject for the SIEVE velocity measurement technique.

  15. Flow Disturbance Characterization Measurements in the National Transonic Facility

    NASA Technical Reports Server (NTRS)

    King, Rudolph A.; Andino, Marlyn Y.; Melton, Latunia; Eppink, Jenna; Kegerise, Michael A.; Tsoi, Andrew

    2012-01-01

    Recent flow measurements have been acquired in the National Transonic Facility (NTF) to assess the unsteady flow environment in the test section. The primary purpose of the test is to determine the feasibility of the NTF to conduct laminar-flow-control testing and boundary-layer transition sensitive testing. The NTF can operate in two modes, warm (air) and cold/cryogenic (nitrogen) test conditions for testing full and semispan scaled models. The warm-air mode enables low to moderately high Reynolds numbers through the use of high tunnel pressure, and the nitrogen mode enables high Reynolds numbers up to flight conditions, depending on aircraft type and size, utilizing high tunnel pressure and cryogenic temperatures. NASA's Environmentally Responsible Aviation (ERA) project is interested in demonstrating different laminar-flow technologies at flight-relevant operating conditions throughout the transonic Mach number range and the NTF is well suited for the initial ground-based demonstrations. Roll polar data at selected test conditions were obtained to look at the uniformity of the flow disturbance field in the test section. Data acquired from the rake probes included mean total temperatures, mean and fluctuating static/total pressures, and mean and fluctuating hot-wire measurements. . Based on the current measurements and previous data, an assessment was made that the NTF is a suitable facility for ground-based demonstrations of laminar-flow technologies at flight-relevant conditions in the cryogenic mode.

  16. Impact of moderate exercise on ovarian blood flow and early embryonic outcomes in mares.

    PubMed

    Smith, R L; Vernon, K L; Kelley, D E; Gibbons, J R; Mortensen, C J

    2012-11-01

    The advent of embryo transfer has allowed horses to continue to train and compete during the breeding season. However, the associated stress of exercise may be detrimental to reproduction. The objectives of this study were to evaluate differing exercise protocols on reproductive blood flow and embryonic outcomes in mares. Light-horse mares were randomized into control (n = 4), partial-exercised (n = 6), and full-exercised (n = 6) groups. Partial-exercised mares were moderately exercised 30 min daily during the periovulatory period and rested after ovulation for 7 d. Full-exercised mares were exercised for 30 min daily throughout the reproductive cycle. Mares were artificially inseminated during estrus and subjected to uterine flush for embryo recovery on d 7 post ovulation. Blood flow through both ovarian arteries and vascular perfusion of the wall of the preovulatory follicle were examined by color Doppler ultrasonography. Results indicated exercise induced greater serum cortisol concentrations (P < 0.05). Embryo recovery rates were reduced in exercised (20/46, 43%) compared with control (14/21, 67%) mares (P < 0.10). When examined separately, embryo recovery rates for partial-exercised (11/25, 44%) and full-exercised (9/21, 43%) mares were not significantly different. Additionally, fewer quality Grade 1 embryos were recovered from partial-exercised mares compared with both control and full-exercised mares (P < 0.05). Blood flow through both ovarian arteries was greater in both exercised groups in the days leading up to ovulation (P < 0.05). However, vascular perfusion of the wall of the preovulatory follicle on the day before ovulation was less in both partial-exercised (45.9 ± 3.0%) and full-exercised (44.8 ± 3.4%) mares vs. control (54.9 ± 3.6%; P < 0.05). In exercised mares, vascular perfusion of the follicle wall was greater when an embryo was recovered (P < 0.01). No differences were found in follicle ovulatory diameter among exercised and non

  17. On preferential flow and its measurement

    SciTech Connect

    Luxmoore, R.J.

    1991-01-01

    Preferential flow is a useful generic term for describing the process whereby water movement through a porous medium follows favored routes bypassing other parts of the medium. This term does not give any indication of the pore scales involved. Sometimes macropore flow is used to describe preferential flow and this term implies that large pores of some sort are conductive. There is no consensus definition of what constitutes a macropore so one needs to carefully determine what is meant when that term is used. The main focus of this report is on the measurement and characterization of preferential flow through structured soils, however, preferred path flow also occurs in sandy soils. Fingering flow in soils, a result of wetting front instability, is a third type of preferential flow that occurs in porous media with more or less random pore arrangement. There may not be any physically defined channels in the soil to account for this type of flow. A larger scale flow described as funnel flow by Kung et al. (1990) results from profile heterogeneity. Low permeability layers or coarse lenses in a profile may restrict vertical drainage redirecting flow laterally through specific regions of the profile (like a funnel). Water repellency can also be a factor in the development of preferential flow. 34 refs.

  18. Investigating of precision measurement on ultrasonic flow

    NASA Astrophysics Data System (ADS)

    Jiang, Fangliang; Ji, Qizheng; Zhai, Dongwei; Dong, Yibo; Dong, Chun

    2015-02-01

    The flow rate is calculated via ultrasonic flow meter (UFM), which is through measuring the difference of time transmitting flow between flow direction and reverse direction. This paper describes the uncertainty analysis for the method of time difference which is commonly used in ultrasonic flow measurement, and the analysis of error source of uncertainty components as well as the general method of elimination. Based on the technique of pseudo random sequence, this paper presents a precise time difference method based on digital correlation technology, and its principle, realization way and uncertainty evaluation are introduced. On the DSP and FPGA system platform, an ultrasonic flow meter scheme based on the digital correlation technology is suggested.

  19. Production of microbubbles from axisymmetric flow focusing in the jetting regime for moderate Reynolds numbers

    NASA Astrophysics Data System (ADS)

    Vega, E. J.; Acero, A. J.; Montanero, J. M.; Herrada, M. A.; Gañán-Calvo, A. M.

    2014-06-01

    We analyze both experimentally and numerically the formation of microbubbles in the jetting regime reached when a moderately viscous liquid stream focuses a gaseous meniscus inside a converging micronozzle. If the total (stagnation) pressure of the injected gas current is fixed upstream, then there are certain conditions on which a quasisteady gas meniscus forms. The meniscus tip is sharpened by the liquid stream down to the gas molecular scale. On the other side, monodisperse collections of microbubbles can be steadily produced in the jetting regime if the feeding capillary is appropriately located inside the nozzle. In this case, the microbubble size depends on the feeding capillary position. The numerical simulations for an imposed gas flow rate show that a recirculation cell appears in the gaseous meniscus for low enough values of that parameter. The experiments allow one to conclude that the bubble pinch-off comprises two phases: (i) a stretching motion of the precursor jet where the neck radius versus the time before the pinch essentially follows a potential law, and (ii) a final stage where a very thin and slender gaseous thread forms and eventually breaks apart into a number of micron-sized bubbles. Because of the difference between the free surface and core velocities, the gaseous jet breakage differs substantially from that of liquid capillary jets and gives rise to bubbles with diameters much larger than those expected from the Rayleigh-type capillary instability. The dependency of the bubble diameter upon the flow-rate ratio agrees with the scaling law derived by A. M. Gañán-Calvo [Phys. Rev. E 69, 027301 (2004), 10.1103/PhysRevE.69.027301], although a slight influence of the Reynolds number can be observed in our experiments.

  20. Production of microbubbles from axisymmetric flow focusing in the jetting regime for moderate Reynolds numbers.

    PubMed

    Vega, E J; Acero, A J; Montanero, J M; Herrada, M A; Gañán-Calvo, A M

    2014-06-01

    We analyze both experimentally and numerically the formation of microbubbles in the jetting regime reached when a moderately viscous liquid stream focuses a gaseous meniscus inside a converging micronozzle. If the total (stagnation) pressure of the injected gas current is fixed upstream, then there are certain conditions on which a quasisteady gas meniscus forms. The meniscus tip is sharpened by the liquid stream down to the gas molecular scale. On the other side, monodisperse collections of microbubbles can be steadily produced in the jetting regime if the feeding capillary is appropriately located inside the nozzle. In this case, the microbubble size depends on the feeding capillary position. The numerical simulations for an imposed gas flow rate show that a recirculation cell appears in the gaseous meniscus for low enough values of that parameter. The experiments allow one to conclude that the bubble pinch-off comprises two phases: (i) a stretching motion of the precursor jet where the neck radius versus the time before the pinch essentially follows a potential law, and (ii) a final stage where a very thin and slender gaseous thread forms and eventually breaks apart into a number of micron-sized bubbles. Because of the difference between the free surface and core velocities, the gaseous jet breakage differs substantially from that of liquid capillary jets and gives rise to bubbles with diameters much larger than those expected from the Rayleigh-type capillary instability. The dependency of the bubble diameter upon the flow-rate ratio agrees with the scaling law derived by A. M. Gañán-Calvo [Phys. Rev. E 69, 027301 (2004)], although a slight influence of the Reynolds number can be observed in our experiments. PMID:25019884

  1. LDA measurements on swirling flows in tubes

    NASA Astrophysics Data System (ADS)

    Kok, M.; Rosendal, F. J.; Brouwers, J. J.

    1993-08-01

    As part of research on swirler stabilized combustors, swirling flows in an expanding and, after a length L, contracting tube are investigated. If the flow is given sufficient rotation in a flow pattern with central recirculation area is measured in a tube with expansion ratio 0.69. In a larger tube with expansion ratio 0.23 a toroidal recirculation area is found. The time dependence of the flow is investigated by determining the autocorrelation function of the velocity signal. In the range of rotational velocities of the flow the flow field is shown to be periodic in time. This is a very interesting phenomenon that occurs only in sufficiently large tubes, with expansion ratio normally encountered in industrial furnaces. Numerical simulation of this flow will be difficult as it is periodically oscillating and probably not axisymmetric.

  2. Flow Rate Measurements Using Flow-Induced Pipe Vibration

    SciTech Connect

    R. P. Evans; Jonathan D. Blotter; Alan G. Stephens

    2004-03-01

    This paper focuses on the possibility of a non-intrusive, low cost, flow rate measurement technique. The technique is based on signal noise from an accelerometer attached to the surface of the pipe. The signal noise is defined as the standard deviation of the frequency averaged time series signal. Experimental results are presented that indicate a nearly quadratic relationship between the signal noise and mass flow rate in the pipe. It is also shown that the signal noise - flow rate relationship is dependant on the pipe material and diameter.

  3. 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.

  4. 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.

  5. Measurements of gamma-ray dose from a moderated /sup 252/Cf source

    SciTech Connect

    McDonald, J.C.; Griffith, R.V.; Plato, P.; Miklos, J.

    1983-06-01

    The gamma-ray dose fraction from a moderated /sup 252/Cf source was determined by using three types of dosimetry systems. Measurements were carried out in air at a distance of 35 cm from the surface of the moderating sphere (50 cm from the source which is at the center of the sphere) to the geometrical center of each detector. The moderating sphere is 0.8-mm-thick stainless steel shell filled with D/sub 2/O and covered with 0.5 mm of cadmium. Measurements were also carried out with instruments and dosimeters positioned at the surface of a 40 cm x 40 cm x 15 cm plexiglass irradiation phantom whose front surface was also 35 cm from the surface of the moderating sphere. A-150 tissue-equivalent (TE) plastic ionization chambers and a TE proportional counter (TEPC) were used to measure tissue dose, from which the neutron dose equivalent was computed. The ratio of gamma-ray dose to the neutron dose equivalent was determined by using a relatively neutron-insensitive Geiger-Mueller (GM) counter and thermoluminescent dosimeters (TLD). In addition, the event-size spectrum measured by the TEPC was also used to compute the gamma-ray dose fraction. The average value for the ratio of gamma-ray dose to neutron dose equivalent was found to be 0.18 with an uncertainty of about +-18%.

  6. Moderate Physical Activity and Its Relationship to Select Measures of a Healthy Diet

    ERIC Educational Resources Information Center

    Blakely, Frank; Dunnagan, Tim; Haynes, George; Moore, Sylvia; Pelican, Suzanne

    2004-01-01

    In rural communities, physical activity may influence and predict nutritional behaviors. The purpose of this investigation was to determine if an individual's stage of participation in moderate physical activity was related to select measures of a healthy diet. Data were collected using a mail-in survey from a random sample conducted in the…

  7. Overview of anisotropic flow measurements from ALICE

    NASA Astrophysics Data System (ADS)

    Zhou, You

    2016-05-01

    Anisotropic flow is an important observable to study the properties of the hot and dense matter, the Quark Gluon Plasma (QGP), created in heavy-ion collisions. Measurements of anisotropic flow for inclusive and identified charged hadrons are reported in Pb-Pb, p-Pb and pp collisions with the ALICE detector. The comparison of experimental measurements to various theoretical calculations are also presented in these proceedings.

  8. Ultrasonic rate measurement of multiphase flow

    SciTech Connect

    Dannert, D.A.; Horne, R.N.

    1993-01-01

    On of the most important tools in production logging and well testing is the downhole flowmeter. Unfortunately, existing tools are inaccurate outside of an idealized single phase flow, regime. Spinner tools are inaccurate at extremely high or low, flow rates and when the flow rate is variable. Radioactive tracer tools have similar inaccuracies and are extremely sensitive to the flow regime. Both tools completely fail in the presence of multiphase flow, whether gas/ oil, gas/water or fluid/solid. Downhole flowmetering is important for locating producing zones and thief zones and monitoring production and injection rates. The effects of stimulation can also be determined. This goal of this project is the investigation of accurate downhole flowmetering techniques for all single phase flow regimes and multiphase flows. The measurement method investigated in this report is the use of ultrasound. There are two ways to use ultrasound for fluid velocity measurement. The first method, examined in Chapter 2, is the contrapropagation, or transit-time, method which compares travel times with and against fluid flow. Chapter 3 details the second method which measures the Doppler frequency shift of a reflected sound wave in the moving fluid. Both of these technologies need to be incorporated in order to build a true multiphase flowmeter. Chapter 4 describes the proposed downhole multiphase flowmeter. It has many advantages besides the ones previously mentioned and is in full in that chapter.

  9. Ultrasonic rate measurement of multiphase flow

    NASA Astrophysics Data System (ADS)

    Dannert, David A.; Horne, Roland N.

    1993-01-01

    One of the most important tools in production logging and well testing is the downhole flowmeter. Unfortunately, existing tools are inaccurate outside of an idealized single phase flow regime. Spinner tools are inaccurate at extremely high or low flow rates and when the flow rate is variable. Radioactive tracer tools have similar inaccuracies and are extremely sensitive to the flow regime. Both tools completely fail in the presence of multiphase flow, whether for gas/oil, gas/water, or fluid/solid. Downhole flowmetering is important for locating producing zones and thief zones and monitoring production and injection rates. The effects of stimulation can also be determined. The goal of this project is the investigation of accurate downhole flowmetering techniques for all single phase flow regimes and multiphase flows. The measurement method investigated in this report is the use of ultrasound. There are two ways to use ultrasound for fluid velocity measurement. The first method, examined in Chapter 2, is the contrapropagation, or transit-time, method which compares travel times with and against fluid flow. Chapter 3 details the second method which measures the Doppler frequency shift of a reflected sound wave in the moving fluid. Both of these technologies need to be incorporated in order to build a true multiphase flowmeter. Chapter 4 describes the proposed downhole multiphase flowmeter.

  10. Measurements of gravity driven granular channel flows

    NASA Astrophysics Data System (ADS)

    Facto, Kevin

    This dissertation presents experiments that studied two gravity driven granular channel flows. The first experiment used magnetic resonance imaging to measure the density and displacement distributions of poppy seeds flowing in a rough walled channel. Time-averaged measurements of normalized velocity and density showed little flow speed dependence. Instantaneous measurements, however, showed marked velocity dependence in the displacement distributions. There was evidence of aperiodic starting and stopping at lower flow speeds and the onset of density waves on a continuous flow at higher speeds. The second experiment measured forces in all three spatial directions at the boundary of a flow of steel balls. The relationship between the normal and the tangential forces were examined statistically and compared to the Coulomb friction model. For both large and small forces, the tangential and normal forces are unrelated, as there appears to be a strong tendency for the tangential force to maintain a value that will bear the weight the weight of the particles in flow.

  11. Investigation of flow structure on a stationary and pitching delta wing of moderate sweep angle using stereoscopic particle image velocimetry

    NASA Astrophysics Data System (ADS)

    Goruney, Tunc

    Near-surface flow patterns along a basic delta wing of moderate sweep angle, representative of key features of Unmanned Combat Air Vehicles (UCAVs) and Micro Air Vehicles (MAVs), are visualized by a technique of high-image-density digital particle image velocimetry (DPIV), which provides quantitative representations of the whole-field flow patterns. Due to the highly three-dimensional nature of the flow patterns, they are also visualized by stereoscopic particle image velocimetry (SPIV). Qualitative dye visualization is employed to complement the DPIV technique. The flow structure is represented by patterns of dye, velocity vectors, streamwise, transverse and out-of-plane velocity components, streamline topology and vorticity. The surface topology, i.e., surface streamlines, and patterns of surface velocity and vorticity oriented normal to the surface of the wing, are investigated by making use of topological rules and critical point theory. For the case of DPIV measurements, the focus is on the time evolution of the surface topology during relaxation of the flow after termination of a pitching maneuver, for a wide range of pitch rates. It is demonstrated that there exists a critical universal state, which marks an abrupt transformation between two distinctly different states of the near-surface pattern of critical points. Moreover, an approach that predicts the occurrence of three-dimensional separation from the surface of the wing, for a wide range of pitch rate, is introduced. For the case of SPIV measurements, the relationship between the three-dimensional flow structure above the surface of the wing and the near-surface topology along the wing has been established, at successive instants following termination of the maneuver. Features of the leading-edge vortex and its breakdown location were quantitatively determined at the termination of the pitching maneuver. For the relaxed state of the flow structure, there is a reference elevation above the wing surface

  12. Probe Without Moving Parts Measures Flow Angle

    NASA Technical Reports Server (NTRS)

    Corda, Stephen; Vachon, M. Jake

    2003-01-01

    The measurement of local flow angle is critical in many fluid-dynamic applications, including the aerodynamic flight testing of new aircraft and flight systems. Flight researchers at NASA Dryden Flight Research Center have recently developed, flight-tested, and patented the force-based flow-angle probe (FLAP), a novel, force-based instrument for the measurement of local flow direction. Containing no moving parts, the FLAP may provide greater simplicity, improved accuracy, and increased measurement access, relative to conventional moving vane-type flow-angle probes. Forces in the FLAP can be measured by various techniques, including those that involve conventional strain gauges (based on electrical resistance) and those that involve more advanced strain gauges (based on optical fibers). A correlation is used to convert force-measurement data to the local flow angle. The use of fiber optics will enable the construction of a miniature FLAP, leading to the possibility of flow measurement in very small or confined regions. This may also enable the tufting of a surface with miniature FLAPs, capable of quantitative flow-angle measurements, similar to attaching yarn tufts for qualitative measurements. The prototype FLAP was a small, aerodynamically shaped, low-aspect-ratio fin about 2 in. (approximately equal to 5 cm) long, 1 in. (approximately equal to 2.5 cm) wide, and 0.125 in. (approximately equal to 0.3 cm) thick (see Figure 1). The prototype FLAP included simple electrical-resistance strain gauges for measuring forces. Four strain gauges were mounted on the FLAP; two on the upper surface and two on the lower surface. The gauges were connected to form a full Wheatstone bridge, configured as a bending bridge. In preparation for a flight test, the prototype FLAP was mounted on the airdata boom of a flight-test fixture (FTF) on the NASA Dryden F-15B flight research airplane.

  13. Damping measurements in flowing water

    NASA Astrophysics Data System (ADS)

    Coutu, A.; Seeley, C.; Monette, C.; Nennemann, B.; Marmont, H.

    2012-11-01

    Fluid-structure interaction (FSI), in the form of mass loading and damping, governs the dynamic response of water turbines, such as Francis turbines. Water added mass and damping are both critical quantities in evaluating the dynamic response of the turbine component. Although the effect of fluid added mass is well documented, fluid damping, a critical quantity to limit vibration amplitudes during service, and therefore to help avoiding possible failure of the turbines, has received much less attention in the literature. This paper presents an experimental investigation of damping due to FSI. The experimental setup, designed to create dynamic characteristics similar to the ones of Francis turbine blades is discussed, together with the experimental protocol and examples of measurements obtained. The paper concludes with the calculated damping values and a discussion on the impact of the observed damping behaviour on the response of hydraulic turbine blades to FSI.

  14. Pancreatic islet blood flow and its measurement.

    PubMed

    Jansson, Leif; Barbu, Andreea; Bodin, Birgitta; Drott, Carl Johan; Espes, Daniel; Gao, Xiang; Grapensparr, Liza; Källskog, Örjan; Lau, Joey; Liljebäck, Hanna; Palm, Fredrik; Quach, My; Sandberg, Monica; Strömberg, Victoria; Ullsten, Sara; Carlsson, Per-Ola

    2016-05-01

    Pancreatic islets are richly vascularized, and islet blood vessels are uniquely adapted to maintain and support the internal milieu of the islets favoring normal endocrine function. Islet blood flow is normally very high compared with that to the exocrine pancreas and is autonomously regulated through complex interactions between the nervous system, metabolites from insulin secreting β-cells, endothelium-derived mediators, and hormones. The islet blood flow is normally coupled to the needs for insulin release and is usually disturbed during glucose intolerance and overt diabetes. The present review provides a brief background on islet vascular function and especially focuses on available techniques to measure islet blood perfusion. The gold standard for islet blood flow measurements in experimental animals is the microsphere technique, and its advantages and disadvantages will be discussed. In humans there are still no methods to measure islet blood flow selectively, but new developments in radiological techniques hold great hopes for the future. PMID:27124642

  15. Pancreatic islet blood flow and its measurement

    PubMed Central

    Jansson, Leif; Barbu, Andreea; Bodin, Birgitta; Drott, Carl Johan; Espes, Daniel; Gao, Xiang; Grapensparr, Liza; Källskog, Örjan; Lau, Joey; Liljebäck, Hanna; Palm, Fredrik; Quach, My; Sandberg, Monica; Strömberg, Victoria; Ullsten, Sara; Carlsson, Per-Ola

    2016-01-01

    Pancreatic islets are richly vascularized, and islet blood vessels are uniquely adapted to maintain and support the internal milieu of the islets favoring normal endocrine function. Islet blood flow is normally very high compared with that to the exocrine pancreas and is autonomously regulated through complex interactions between the nervous system, metabolites from insulin secreting β-cells, endothelium-derived mediators, and hormones. The islet blood flow is normally coupled to the needs for insulin release and is usually disturbed during glucose intolerance and overt diabetes. The present review provides a brief background on islet vascular function and especially focuses on available techniques to measure islet blood perfusion. The gold standard for islet blood flow measurements in experimental animals is the microsphere technique, and its advantages and disadvantages will be discussed. In humans there are still no methods to measure islet blood flow selectively, but new developments in radiological techniques hold great hopes for the future. PMID:27124642

  16. NMRI Measurements of Flow of Granular Mixtures

    NASA Technical Reports Server (NTRS)

    Nakagawa, Masami; Waggoner, R. Allen; Fukushima, Eiichi

    1996-01-01

    We investigate complex 3D behavior of granular mixtures in shaking and shearing devices. NMRI can non-invasively measure concentration, velocity, and velocity fluctuations of flows of suitable particles. We investigate origins of wall-shear induced convection flow of single component particles by measuring the flow and fluctuating motion of particles near rough boundaries. We also investigate if a mixture of different size particles segregate into their own species under the influence of external shaking and shearing disturbances. These non-invasive measurements will reveal true nature of convecting flow properties and wall disturbance. For experiments in a reduced gravity environment, we will design a light weight NMR imager. The proof of principle development will prepare for the construction of a complete spaceborne system to perform experiments in space.

  17. Electromagnetic probe technique for fluid flow measurements

    NASA Technical Reports Server (NTRS)

    Arndt, G. D.; Carl, J. R.

    1994-01-01

    The probes described herein, in various configurations, permit the measurement of the volume fraction of two or more fluids flowing through a pipe. Each probe measures the instantaneous relative dielectric constant of the fluid in immediate proximity. As long as separation of the relative dielectric constant of the fluid is possible, several or even many fluids can be measured in the same flow stream. By using multiple probes, the velocity of each fluid can generally be determined as well as the distribution of each constituent in the pipe. The values are determined by statistical computation. There are many potential applications for probes of this type in industry and government. Possible NASA applications include measurements of helium/hydrazine flow during rocket tests at White Sands, liquid/gas flow in hydrogen or oxygen lines in Orbiter engines, and liquid/gaseous Freon flow in zero gravity tests with the KS135 aircraft at JSC. Much interest has been shown recently by the oil industry. In this a good method is needed to measure the fractions of oil, water, and natural gas flowing in a pipeline and the velocity of each. This particular problem involves an extension of what has been developed to date and our plans to solve this problem will be discussed herein.

  18. Unsteady Dynamics of free falling of multi flexible fibers in moderate Reynolds number flows

    NASA Astrophysics Data System (ADS)

    Qi, Dewei

    2007-11-01

    The direct simulations of sedimentation of single and multi flexible fibers are conducted in moderate Reynolds number flows by using a newly developed method. In the method, for fluid domain, the lattice Boltzmann equations are used to solve the Navier Stokes equations. For solid domain, a fiber is discretized as a chain of rigid segments. The segments are connected through ball and socket joints and can be bent and twisted. Constraint forces are introduced at each joint. Translation and rotation matrix of fiber are linearized with respect to the constraint forces up to a second order of time step. Thus, motion of the fiber under the constraint and hydrodynamic forces could be solved by using a modified leap-frog algorithm. Effects of many body interaction on fiber fluttering are studied. It is found that in the same conditions initial fluttering may be damped by fluid viscosity for a single flexible fiber while irregular and persistent fluttering, rocking and oscillation may occur for a multi- fiber system. It is evident that clusters, such as doublets and triplets, are spontaneously formed and have a profound impact on unsteady dynamics of fibers. Two mechanisms contribute to an increase in unsteadiness. First the clusters have larger local settling velocity than a single fiber. Second, closely packed fibers become more ``fat'' or ``thick'' body and have a lower effective aspect ratio. The flows behind the 'fat' clusters tend to be more unsteady and induce vortex shedding that causes fibers persistently fluttering, rocking or oscillating. It is found that a fiber chain with a long vertical dimension is not stable. They will break down and become more flat structure. This property is directly related to that the fiber is preferentially oriented in horizontal direction due to inertia. In addition, the effects of flexibility on unsteady dynamics of sedimentation of flexible fiber are studied in a given range of Re. We find that when stiffness is very large, the

  19. Unsteady measurement techniques for turbomachinery flows

    NASA Astrophysics Data System (ADS)

    Jaffa, Nicholas Andrew

    Accurate unsteady measurements are required for studying the flows in high speed turbomachines, which rely on the interaction between rotating and stationary components. Using statistics of phase locked ensembles simplifies the problem, but accurate frequency response in the 10-100 kHz range significantly limits the applicable techniques. This research advances the state of the art for phase resolved measurement techniques using for high speed turbomachinery flows focusing on the following areas: development, validation, and uncertainty quantification. Four methods were developed and implemented: an unsteady total pressure probe, the multiple overheat hot-wire method, the slanted hot-wire method, and the phase peak yaw hot-wire method. These methods allow for the entire phase locked average flow field to be measured (temperature, pressure, and velocity components, swirl angle, etc.). No trusted reference measurement or representative canonical flow exists for comparison of the phase resolved quantities, making validation challenging. Five different validation exercises were performed to increase the confidence and explore the range of applicability. These exercises relied on checking for consistency with expected flow features, comparing independent measurements, and cross validation with CFD. The combined uncertainties for the measurements were quantified using uncertainty estimates from investigations into the elemental error sources. The frequency response uncertainty of constant temperature hot-wire system was investigated using a novel method of illuminating the wire with a laser pulse. The uncertainty analysis provided estimates for the uncertainty in the measurements as well as showing the sensitivity to various sources of error.

  20. Ultrasonic flow measurements for irrigation process monitoring

    NASA Astrophysics Data System (ADS)

    Ziani, Elmostafa; Bennouna, Mustapha; Boissier, Raymond

    2004-02-01

    This paper presents the state of the art of the general principle of liquid flow measurements by ultrasonic method, and problems of flow measurements. We present an ultrasonic flowmeter designed according to smart sensors concept, for the measurement of irrigation water flowing through pipelines or open channels, using the ultrasonic transit time approach. The new flowmeter works on the principle of measuring time delay differences between sound pulses transmitted upstream and downstream in the flowing liquid. The speed of sound in the flowing medium is eliminated as a variable because the flowrate calculations are based on the reciprocals of the transmission times. The transit time difference is digitally measured by means of a suitable, microprocessor controlled logic. This type of ultrasonic flowmeter will be widely used in industry and water management, it is well studied in this work, followed by some experimental results. For pressurized channels, we use one pair of ultrasonic transducer arranged in proper positions and directions of the pipe, in this case, to determine the liquid velocity, a real time on-line analysis taking account the geometries of the hydraulic system, is applied to the obtained ultrasonic data. In the open channels, we use a single or two pairs of ultrasonic emitter-receiver according to the desired performances. Finally, the goals of this work consist in integrating the smart sensor into irrigation systems monitoring in order to evaluate potential advantages and demonstrate their performance, on the other hand, to understand and use ultrasonic approach for determining flow characteristics and improving flow measurements by reducing errors caused by disturbances of the flow profiles.

  1. Spectroscopic Measurement Techniques for Aerospace Flows

    NASA Technical Reports Server (NTRS)

    Danehy, Paul M.; Bathel, Brett F.; Johansen, Craig T.; Cutler, Andrew D.; Hurley, Samantha

    2014-01-01

    The conditions that characterize aerospace flows are so varied, that a single diagnostic technique is not sufficient for its measurement. Fluid dynamists use knowledge of similarity to help categorize and focus on different flow conditions. For example, the Reynolds number represents the ratio of inertial to viscous forces in a flow. When the velocity scales, length scales, and gas density are large and the magnitude of the molecular viscosity is low, the Reynolds number becomes large. This corresponds to large scale vehicles (e.g Airbus A380), fast moving objects (e.g. artillery projectiles), vehicles in dense fluids (e.g. submarine in water), or flows with low dynamic viscosity (e.g. skydiver in air). In each of these cases, the inertial forces dominate viscous forces, and unsteady turbulent fluctuations in the flow variables are observed. In contrast, flows with small length scales (e.g. dispersion of micro-particles in a solid rocket nozzle), slow moving objects (e.g. micro aerial vehicles), flows with low density gases (e.g. atmospheric re-entry), or fluids with a large magnitude of viscosity (e.g. engine coolant flow), all have low Reynolds numbers. In these cases, viscous forces become very important and often the flows can be steady and laminar. The Mach number, which is the ratio of the velocity to the speed of sound in the medium, also helps to differentiate types of flows. At very low Mach numbers, acoustic waves travel much faster than the object, and the flow can be assumed to be incompressible (e.g. Cessna 172 aircraft). As the object speed approaches the speed of sound, the gas density can become variable (e.g. flow over wing of Learjet 85). When the object speed is higher than the speed of sound (Ma > 1), the presences of shock waves and other gas dynamic features can become important to the vehicle performance (e.g. SR-71 Blackbird). In the hypersonic flow regime (Ma > 5), large changes in temperature begin to affect flow properties, causing real

  2. PERFORMING QUALITY FLOW MEASUREMENTS AT MINE SITES

    EPA Science Inventory

    Accurate flow measurement data is vital to research, monitoring, and remediation efforts at mining sites. This guidebook has been prepared to provide a summary of information relating to the performance of low measurements, and how this information can be applied at mining sites....

  3. Wastewater Sampling Methodologies and Flow Measurement Techniques.

    ERIC Educational Resources Information Center

    Harris, Daniel J.; Keffer, William J.

    This document provides a ready source of information about water/wastewater sampling activities using various commercial sampling and flow measurement devices. The report consolidates the findings and summarizes the activities, experiences, sampling methods, and field measurement techniques conducted by the Environmental Protection Agency (EPA),…

  4. Yield stress measurements using novel squeezing flows

    NASA Astrophysics Data System (ADS)

    Ward, Daniel

    Techniques for measuring the yield stress of materials are numerous, but often plagued with difficulties and uncertainties in measurement. The primary methods include shear rheometry and, more recently, squeezing flow. Shear rheometry requires care on the part of the experimentalist to generate uniform flow fields and avoid shear banding or wall slip which may interfere with measurements. Squeezing flow tests are often performed with poorly controlled boundary conditions creating complicated flow fields. Further, the effects of the experimental modifications made to produce these boundary conditions in measurements are often not investigated and simply ignored. The main objective of this study was to develop a novel measuring technique to study the yield stress behavior of a model material, Carbopol. First attempts were made towards a novel lubricant injection squeezing (LIS) flow technique based on the continuous lubricated squeezing flow (CLSF) setup, as well as a novel lubricant film squeezing (LFS) technique which will allow measurement of the yield stress without the complicated treatment of either the sample or experimental setup required by currently favored methods. The novel techniques were developed and validated by direct comparison with shear measurements, the current gold standard for determining yield stress. Common squeezing techniques for characterizing yield stress fluids were also compared and found to be inadequate and inconsistent when compared to the shear measurements. The results from this study showed that the LIS and LFS methods are able to qualitatively determine a yield stress, but further investigation is required before they can be achieve their full potential as viable methods for determine yield stress.

  5. Flow patterns measurements with PIV laser method

    NASA Astrophysics Data System (ADS)

    Podlinski, Janusz; Kocik, Marek; Dors, Miroslaw; Metel, Emilia; Mizeraczyk, Jerzy

    2007-03-01

    In this paper a Particle Image Velocimetry (PIV) measurement technique and it's application for the flow patterns measurements in our experiments is presented. Present PIV system consist of double Nd:YAG laser with pulse energy of 50 mJ, optics for transmission and formation a laser beam, two CCD cameras (Kodak MegaPlus ES-1.0 and FlowSense M2), Dantec processor PIV 1100 and PC computer with FlowManager software. The maximum measured area is 0.5 m2 and flow velocity in the range of 0-300 m/s. So far, the PIV measurements were carried out in hydrodynamic and transonic ducts, corona discharge reactors, electrostatic precipitator models and a microwave torch discharge reactor in The Szewalski Institute of Fluid Flow Machinery, Polish Academy of Sciences in Gdansk. The PIV system was used also for the measurements of the velocity fields round the hull of the ship model in The Ship Design and Research Centre in Gdansk.

  6. Depth selective acousto-optic flow measurement

    PubMed Central

    Tsalach, Adi; Schiffer, Zeev; Ratner, Eliahu; Breskin, Ilan; Zeitak, Reuven; Shechter, Revital; Balberg, Michal

    2015-01-01

    Optical based methods for non-invasive measurement of regional blood flow tend to incorrectly assess cerebral blood flow, due to contribution of extra-cerebral tissues to the obtained signal. We demonstrate that spectral analysis of phase-coded light signals, tagged by specific ultrasound patterns, enables differentiation of flow patterns at different depths. Validation of the model is conducted by Monte Carlo simulation. In-vitro experiments demonstrate good agreement with the simulations' results and provide a solid validation to depth discrimination ability. These results suggest that signal contamination originating from extra-cerebral tissue may be eliminated using spectral analysis of ultrasonically tagged light. PMID:26713201

  7. Comparison between measured and predicted resting metabolic rate in moderately active adolescents.

    PubMed

    De Lorenzo A; Bertini, I; Puijia, A; Testolin, G; Testolin, C

    1999-09-01

    The aim of this study was to check the validity of predictive equations for the calculation of resting metabolic rate (RMR) in moderately active adolescents. The RMR was measured in a sample of 25 healthy 15.5-18.2-year-old boys practicing soccer. The RMR was assessed by indirect calorimetry for 30 min following an overnight fast. Body composition was estimated from skinfold thickness measurements. Among the available equations to predict RMR, we decided to use those a of Molnar et al., Harris-Benedict, Schofield, and Cunningham. Measured and predicted values were compared by means of a one-way ANOVA. Also the Bland-Altman test was performed in order to evaluate the accuracy of the prediction equations compared to the measured value. The measured RMR was found to be 1834 +/- 160 kcal/day (mean +/- SD), while the Molnar et al., Schofield, Harris-Benedict, and Cunningham predicted values were 1707 +/- 78, 1866 +/- 89, 1779 +/- 84 and 1830 +/- 87 kcal/day, respectively. On average, compared to the measured values only the Molnar et al. equation differed significantly. On an individual basis, all the equations demonstrated considerable variability between measured and predicted RMRs. The predicted values also differed significantly. As regards the moderately active subjects (16-18 years old), we recommend the use of the Schofield equation, based on simple anthropometric parameters and also that of Cunningham, even if the estimation or measurement of fat-free mass may be cumbersome for everyday pediatric use. PMID:10664318

  8. Are flow measurements at RHIC reliable?

    NASA Astrophysics Data System (ADS)

    Taranenko, Arkadiy; Vishnyakov, Vladislav

    2016-01-01

    The measurements of collective flow effects in particle production have provided invaluable insights on the transport properties of the strongly interacting matter produced in relativistic heavy-ion collisions at RHIC. The detailed comparison of flow measurements from PHENIX and STAR experiments at RHIC have been presented and discussed. For elliptic flow ν2 of charged hadrons from Au+Au collisions at 200 GeV the two data sets overlap excellently for centralities > 20%, they increasingly diverge at small centralities, with a 30% difference between STAR an PHENIX in the 0-5% centrality bin. For ν3 values the agreement is much worse and coming from the difference in STAR measurements. More investigations are needed to understand the reason for such differences.

  9. Intercomparison of flow measurements at RHIC experiments

    NASA Astrophysics Data System (ADS)

    Vdovkina, S. S.

    2016-02-01

    The measurements of collective flow effects in particle production have provided invaluable insights on the transport properties of the strongly interacting matter produced in relativistic heavy-ion collisions at RHIC. The detailed comparison of flow measurements from PHENIX and STAR experiments at RHIC have been presented and discussed. For elliptic flow v2 of charged hadrons from Au+Au collisions at 200 GeV the two data sets overlap excellently for centralities > 20%, they increasingly diverge at small centralities, with a 30% difference between STAR an PHENIX in the 0-5% centrality bin. For v3 values the agreement is much worse and coming from the difference in STAR measurements. More investigations are needed to understand the reason for such differences.

  10. Coherent Raman spectroscopy for supersonic flow measurments

    NASA Technical Reports Server (NTRS)

    She, C. Y.

    1986-01-01

    In collaboration with NASA/Langley Research Center, a truly nonintrusive and nonseeding method for measuring supersonic molecular flow parameters was proposed and developed at Colorado State University. The feasibility of this Raman Doppler Velocimetry (RDV), currently operated in a scanning mode, was demonstrated not only in a laboratory environment at Colorado State University, but also in a major wind tunnel at NASA/Langley Research Center. The research progress of the RDV development is summarized. In addition, methods of coherent Rayleigh-Brillouin spectroscopy and single-pulse coherent Raman spectroscopy are investigated, respectively, for measurements of high-pressure and turbulent flows.

  11. Slip length measurement of gas flow.

    PubMed

    Maali, Abdelhamid; Colin, Stéphane; Bhushan, Bharat

    2016-09-16

    In this paper, we present a review of the most important techniques used to measure the slip length of gas flow on isothermal surfaces. First, we present the famous Millikan experiment and then the rotating cylinder and spinning rotor gauge methods. Then, we describe the gas flow rate experiment, which is the most widely used technique to probe a confined gas and measure the slip. Finally, we present a promising technique using an atomic force microscope introduced recently to study the behavior of nanoscale confined gas. PMID:27505860

  12. Slip length measurement of gas flow

    NASA Astrophysics Data System (ADS)

    Maali, Abdelhamid; Colin, Stéphane; Bhushan, Bharat

    2016-09-01

    In this paper, we present a review of the most important techniques used to measure the slip length of gas flow on isothermal surfaces. First, we present the famous Millikan experiment and then the rotating cylinder and spinning rotor gauge methods. Then, we describe the gas flow rate experiment, which is the most widely used technique to probe a confined gas and measure the slip. Finally, we present a promising technique using an atomic force microscope introduced recently to study the behavior of nanoscale confined gas.

  13. Unsteady 2-phase flow instrumentation and measurement

    NASA Astrophysics Data System (ADS)

    Bernier, R. J.

    The performance of a transverse field electromagnetic flowmeter in a steady two phase flow was investigated analytically for a disperse and an annular flow regime. The flowmeter output voltage was found to be proportional to the mean velocity of the liquid phase. Experiments in a steady air water mixture showed good agreement with the analysis. An impedance void fraction meter was designed and built to conduct measurements of unsteady void fractions. Short electrodes excited by voltages of opposite polarity were used in combination with a highly sensitive signal processor. The steady state calibration indicated that the meter was somewhat sensitive to the void fraction distribution for the bubbly flow regime. However, the transition to a churn turbulent regime greatly affected the meer steady state response. The dynamic capability of the void fraction meter was estimated by comparison of the statistical properties of the voltage fluctuations in a nominally steady bubbly flow with those of a shot noise process.

  14. Fluid Flow Technology that Measures Up

    NASA Technical Reports Server (NTRS)

    2004-01-01

    From 1994 to 1996, NASA s Marshall Space Flight Center conducted a Center Director's Discretionary Fund research effort to apply artificial intelligence technologies to the health management of plant equipment and space propulsion systems. Through this effort, NASA established a business relationship with Quality Monitoring and Control (QMC), of Kingwood, Texas, to provide hardware modeling and artificial intelligence tools. Very detailed and accurate Space Shuttle Main Engine (SSME) analysis and algorithms were jointly created, which identified several missing, critical instrumentation needs for adequately evaluating the engine health status. One of the missing instruments was a liquid oxygen (LOX) flow measurement. This instrument was missing since the original SSME included a LOX turbine flow meter that failed during a ground test, resulting in considerable damage for NASA. New balanced flow meter technology addresses this need with robust, safe, and accurate flow metering hardware.

  15. Evaluation of the Boron Dilution Method for Moderator Temperature Coefficient Measurements

    SciTech Connect

    Demaziere, Christophe; Pazsit, Imre; Por, Gabor

    2002-11-15

    A measurement of the at-power moderator temperature coefficient (MTC) at the pressurized water reactor Unit 4 of the Ringhals Nuclear Power Plant (Sweden) during fuel cycle 16 is analyzed. The measurement was performed when the boron concentration decreased under 300 ppm in the reactor coolant system, by using the boron dilution method. Detailed calculations were made to estimate all reactivity effects taking place during such a measurement. These effects can only be accounted for through static core calculations that allow calculating contributions to the reactivity change induced by the moderator temperature change. All the calculations were performed with the Studsvik Scandpower SIMULATE-3 code. Analysis of the measurement showed that the contribution of the Doppler effect (in the fuel) was almost negligible, whereas the reactivity effects due to other than the Doppler fuel coefficient and the boron change were surprisingly significant. It was concluded that due to the experimental inaccuracies, the uncertainty associated with the boron dilution method could be much larger than previously expected. The MTC might then be close to -72 pcm/degC, whereas the main goal of the measurement is to verify that the MTC is larger (less negative) than this threshold. The usefulness of the boron dilution method for MTC measurements can therefore be questioned.

  16. Energy measurement using flow computers and chromatography

    SciTech Connect

    Beeson, J.

    1995-12-01

    Arkla Pipeline Group (APG), along with most transmission companies, went to electronic flow measurement (EFM) to: (1) Increase resolution and accuracy; (2) Real time correction of flow variables; (3) Increase speed in data retrieval; (4) Reduce capital expenditures; and (5) Reduce operation and maintenance expenditures Prior to EFM, mechanical seven day charts were used which yielded 800 pressure and differential pressure readings. EFM yields 1.2-million readings, a 1500 time improvement in resolution and additional flow representation. The total system accuracy of the EFM system is 0.25 % compared with 2 % for the chart system which gives APG improved accuracy. A typical APG electronic measurement system includes a microprocessor-based flow computer, a telemetry communications package, and a gas chromatograph. Live relative density (specific gravity), BTU, CO{sub 2}, and N{sub 2} are updated from the chromatograph to the flow computer every six minutes which provides accurate MMBTU computations. Because the gas contract length has changed from years to monthly and from a majority of direct sales to transports both Arkla and its customers wanted access to actual volumes on a much more timely basis than is allowed with charts. The new electronic system allows volumes and other system data to be retrieved continuously, if EFM is on Supervisory Control and Data Acquisition (SCADA) or daily if on dial up telephone. Previously because of chart integration, information was not available for four to six weeks. EFM costs much less than the combined costs of telemetry transmitters, pressure and differential pressure chart recorders, and temperature chart recorder which it replaces. APG will install this equipment on smaller volume stations at a customers expense. APG requires backup measurement on metering facilities this size. It could be another APG flow computer or chart recorder, or the other companies flow computer or chart recorder.

  17. NMR Measurements of Granular Flow and Compaction

    NASA Astrophysics Data System (ADS)

    Fukushima, Eiichi

    1998-03-01

    Nuclear magnetic resonance (NMR) can be used to measure statistical distributions of granular flow velocity and fluctuations of velocity, as well as spatial distributions of particulate concentration, flow velocity, its fluctuations, and other parameters that may be derived from these. All measurements have been of protons in liquid-containing particles such as mustard seeds or pharmaceutical pills. Our favorite geometry has been the slowly rotating partially filled rotating drum with granular flow taking place along the free surface of the particles. All the above-mentioned parameters have been studied as well as a spatial distribution of particulate diffusion coefficients, energy dissipation due to collisions, as well as segregation of non-uniform mixtures of granular material. Finally, we describe some motions of granular material under periodic vibrations.

  18. Optical Air Flow Measurements in Flight

    NASA Technical Reports Server (NTRS)

    Bogue, Rodney K.; Jentink, Henk W.

    2004-01-01

    This document has been written to assist the flight-test engineer and researcher in using optical flow measurements in flight applications. The emphasis is on describing tradeoffs in system design to provide desired measurement performance as currently understood. Optical system components are discussed with examples that illustrate the issues. The document concludes with descriptions of optical measurement systems designed for a variety of applications including aeronautics research, airspeed measurement, and turbulence hazard detection. Theoretical discussion is minimized, but numerous references are provided to supply ample opportunity for the reader to understand the theoretical underpinning of optical concepts.

  19. Recent advancement of turbulent flow measurement techniques

    NASA Technical Reports Server (NTRS)

    Battle, T.; Wang, P.; Cheng, D. Y.

    1974-01-01

    Advancements of the fluctuating density gradient cross beam laser Schlieren technique, the fluctuating line-reversal temperature measurement and the development of the two-dimensional drag-sensing probe to a three-dimensional drag-sensing probe are discussed. The three-dimensionality of the instantaneous momentum vector can shed some light on the nature of turbulence especially with swirling flow. All three measured fluctuating quantities (density, temperature, and momentum) can provide valuable information for theoreticians.

  20. Review of air flow measurement techniques

    SciTech Connect

    McWilliams, Jennifer

    2002-12-01

    Airflow measurement techniques are necessary to determine the most basic of indoor air quality questions: ''Is there enough fresh air to provide a healthy environment for the occupants of the building?'' This paper outlines airflow measurement techniques, but it does not make recommendations for techniques that should be used. The airflows that will be discussed are those within a room or zone, those between rooms or zones, such as through doorways (open or closed) or passive vents, those between the building and outdoors, and those through mechanical air distribution systems. Techniques that are highlighted include particle streak velocimetry, hot wire anemometry, fan pressurization (measuring flow at a given pressure), tracer gas, acoustic methods for leak size determination, the Delta Q test to determine duct leakage flows, and flow hood measurements. Because tracer gas techniques are widely used to measure airflow, this topic is broken down into sections as follows: decay, pulse injection, constant injection, constant concentration, passive sampling, and single and multiple gas measurements for multiple zones.

  1. Development of microcontroller based water flow measurement

    NASA Astrophysics Data System (ADS)

    Munir, Muhammad Miftahul; Surachman, Arif; Fathonah, Indra Wahyudin; Billah, Muhammad Aziz; Khairurrijal, Mahfudz, Hernawan; Rimawan, Ririn; Lestari, Slamet

    2015-04-01

    A digital instrument for measuring water flow was developed using an AT89S52 microcontroller, DS1302 real time clock (RTC), and EEPROM for an external memory. The sensor used for probing the current was a propeller that will rotate if immersed in a water flow. After rotating one rotation, the sensor sends one pulse and the number of pulses are counted for a certain time of counting. The measurement data, i.e. the number of pulses per unit time, are converted into water flow velocity (m/s) through a mathematical formula. The microcontroller counts the pulse sent by the sensor and the number of counted pulses are stored into the EEPROM memory. The time interval for counting is provided by the RTC and can be set by the operator. The instrument was tested under various time intervals ranging from 10 to 40 seconds and several standard propellers owned by Experimental Station for Hydraulic Structure and Geotechnics (BHGK), Research Institute for Water Resources (Pusair). Using the same propellers and water flows, it was shown that water flow velocities obtained from the developed digital instrument and those found by the provided analog one are almost similar.

  2. Solids flow rate measurement in dense slurries

    SciTech Connect

    Porges, K.G.; Doss, E.D.

    1993-09-01

    Accurate and rapid flow rate measurement of solids in dense slurries remains an unsolved technical problem, with important industrial applications in chemical processing plants and long-distance solids conveyance. In a hostile two-phase medium, such a measurement calls for two independent parameter determinations, both by non-intrusive means. Typically, dense slurries tend to flow in laminar, non-Newtonian mode, eliminating most conventional means that usually rely on calibration (which becomes more difficult and costly for high pressure and temperature media). These issues are reviewed, and specific solutions are recommended in this report. Detailed calculations that lead to improved measuring device designs are presented for both bulk density and average velocity measurements. Cross-correlation, chosen here for the latter task, has long been too inaccurate for practical applications. The cause and the cure of this deficiency are discussed using theory-supported modeling. Fluid Mechanics are used to develop the velocity profiles of laminar non-Newtonian flow in a rectangular duct. This geometry uniquely allows the design of highly accurate `capacitive` devices and also lends itself to gamma transmission densitometry on an absolute basis. An absolute readout, though of less accuracy, is also available from a capacitive densitometer and a pair of capacitive sensors yields signals suitable for cross-correlation velocity measurement.

  3. Flow rate measurement in aggressive conductive fluids

    NASA Astrophysics Data System (ADS)

    Dubovikova, Nataliia; Kolesnikov, Yuri; Karcher, Christian

    2014-03-01

    Two non-contact experimental methods of flow rate measurements for aggressive conductive liquids are described. The techniques are based on electromagnetic forces and Faraday's law: Lorentz force is induced inside moving conductive liquid under influence of variable magnetic field of permanent magnets. They are mounted along a liquid metal channel or (in case of the second method) inserted into rotated metal wheels. The force acts in the opposite of fluids' velocity direction and hence it is possible to measure reaction force of it that takes place according to Newton's law on magnetic field source - permanent magnets. And by knowing the force, which linearly depends on velocity, one can calculate mean flow rate of liquid. In addition experimental "dry" calibration and its results are described for one of the measurements' techniques.

  4. Rectangular subsonic jet flow field measurements

    NASA Technical Reports Server (NTRS)

    Morrison, Gerald L.; Swan, David H.

    1990-01-01

    Flow field measurements of three subsonic rectangular cold air jets are presented. The three cases had aspect ratios of 1x2, 1x4 at a Mach number of 0.09 and an aspect ratio of 1x2 at a Mach number of 0.9. All measurements were made using a 3-D laser Doppler anemometer system. The data includes the mean velocity vector, all Reynolds stress tensor components, turbulent kinetic energy and velocity correlation coefficients. The data are presented in tabular and graphical form. No analysis of the measured data or comparison to other published data is made.

  5. Hall effect in electrolyte flow measurements: introduction to blood flow measurements.

    PubMed

    Szwast, Maciej; Piatkiewicz, Wojciech

    2012-06-01

    The Hall effect has been applied to electrolyte flow measurement. It has been proven that Hall voltage does not depend on electrolyte concentration; however, there is a linear relationship between Hall voltage and flow velocity. Obtained results for electrolyte allow us to suppose that Hall effect can be used to determine blood flow. Research on blood will be conducted as the next step. PMID:22145845

  6. Unified Model Deformation and Flow Transition Measurements

    NASA Technical Reports Server (NTRS)

    Burner, Alpheus W.; Liu, Tianshu; Garg, Sanjay; Bell, James H.; Morgan, Daniel G.

    1999-01-01

    The number of optical techniques that may potentially be used during a given wind tunnel test is continually growing. These include parameter sensitive paints that are sensitive to temperature or pressure, several different types of off-body and on-body flow visualization techniques, optical angle-of-attack (AoA), optical measurement of model deformation, optical techniques for determining density or velocity, and spectroscopic techniques for determining various flow field parameters. Often in the past the various optical techniques were developed independently of each other, with little or no consideration for other techniques that might also be used during a given test. Recently two optical techniques have been increasingly requested for production measurements in NASA wind tunnels. These are the video photogrammetric (or videogrammetric) technique for measuring model deformation known as the video model deformation (VMD) technique, and the parameter sensitive paints for making global pressure and temperature measurements. Considerations for, and initial attempts at, simultaneous measurements with the pressure sensitive paint (PSP) and the videogrammetric techniques have been implemented. Temperature sensitive paint (TSP) has been found to be useful for boundary-layer transition detection since turbulent boundary layers convect heat at higher rates than laminar boundary layers of comparable thickness. Transition is marked by a characteristic surface temperature change wherever there is a difference between model and flow temperatures. Recently, additional capabilities have been implemented in the target-tracking videogrammetric measurement system. These capabilities have permitted practical simultaneous measurements using parameter sensitive paint and video model deformation measurements that led to the first successful unified test with TSP for transition detection in a large production wind tunnel.

  7. Research Performance Measures and the Moderating Role of Faculty Characteristics in Epidemiology

    PubMed Central

    Okhovati, Maryam; Bazrafshan, Azam; Zare, Morteza; Moradzadeh, Mina; Mokhtari, Ali Mohammad

    2016-01-01

    Several numeric measures have been proposed to evaluate the individual researchers’ scientific performance. Among these measures, h-index is the most common and well recognized measure of research productivity and impact in scientific communities. However, empirical investigations and recent inspections revealed some shortcomings and limitations of this measure. In order to complement these limitations, several variants have been proposed in which g-index and ar-index were among the most discussed measures. The aim of this study was to examine h-index, g-index and ar-index across Iranian epidemiologists to identify the moderating characteristics as well as the distribution of these measures in the field. Using Web of Science Database, a list of Iranian epidemiologists was searched and total number of articles, total citations, and citations per paper, h-index, scientific age, g-index and ar-index were extracted and calculated for any epidemiologist. Descriptive statistics and multivariate linear regression models were used to examine research performance measures of Iranian epidemiologists. According to our findings, research performance measures found to be statistically associated with scientific age and academic ranking of Iranian Epidemiologists. Gender differences were not relevant to research performance across different measures. PMID:26652082

  8. 40 CFR 91.417 - Fuel flow measurement specifications.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 21 2013-07-01 2013-07-01 false Fuel flow measurement specifications... Procedures § 91.417 Fuel flow measurement specifications. (a) Fuel flow measurement is required only for raw testing but is allowed for dilute testing. (b) The fuel flow rate measurement instrument must have...

  9. 40 CFR 91.417 - Fuel flow measurement specifications.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 20 2011-07-01 2011-07-01 false Fuel flow measurement specifications... Procedures § 91.417 Fuel flow measurement specifications. (a) Fuel flow measurement is required only for raw testing but is allowed for dilute testing. (b) The fuel flow rate measurement instrument must have...

  10. 40 CFR 91.417 - Fuel flow measurement specifications.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Fuel flow measurement specifications... Procedures § 91.417 Fuel flow measurement specifications. (a) Fuel flow measurement is required only for raw testing but is allowed for dilute testing. (b) The fuel flow rate measurement instrument must have...

  11. 40 CFR 91.417 - Fuel flow measurement specifications.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 21 2012-07-01 2012-07-01 false Fuel flow measurement specifications... Procedures § 91.417 Fuel flow measurement specifications. (a) Fuel flow measurement is required only for raw testing but is allowed for dilute testing. (b) The fuel flow rate measurement instrument must have...

  12. 40 CFR 91.416 - Intake air flow measurement specifications.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Intake air flow measurement... Procedures § 91.416 Intake air flow measurement specifications. (a) If used, the engine intake air flow measurement method used must have a range large enough to accurately measure the air flow over the...

  13. EDITORIAL: Measurement techniques for multiphase flows Measurement techniques for multiphase flows

    NASA Astrophysics Data System (ADS)

    Okamoto, Koji; Murai, Yuichi

    2009-11-01

    Research on multiphase flows is very important for industrial applications, including power stations, vehicles, engines, food processing and so on. Multiphase flows originally have nonlinear features because of multiphase systems. The interaction between the phases plays a very interesting role in the flows. The nonlinear interaction causes the multiphase flows to be very complicated. Therefore techniques for measuring multiphase flows are very useful in helping to understand the nonlinear phenomena. The state-of-the-art measurement techniques were presented and discussed at the sixth International Symposium on Measurement Techniques for Multiphase Flows (ISMTMF2008) held in Okinawa, Japan, on 15-17 December 2008. This special feature of Measurement Science and Technology includes selected papers from ISMTMF2008. Okinawa has a long history as the Ryukyus Kingdom. China, Japan and many western Pacific countries have had cultural and economic exchanges through Okinawa for over 1000 years. Much technical and scientific information was exchanged at the symposium in Okinawa. The proceedings of ISMTMF2008 apart from these special featured papers were published in Journal of Physics: Conference Series vol. 147 (2009). We would like to express special thanks to all the contributors to the symposium and this special feature. This special feature will be a milestone in measurement techniques for multiphase flows.

  14. Aerodynamic Flow Field Measurements for Automotive Systems

    NASA Technical Reports Server (NTRS)

    Hepner, Timothy E.

    1999-01-01

    The design of a modern automotive air handling system is a complex task. The system is required to bring the interior of the vehicle to a comfortable level in as short a time as possible. A goal of the automotive industry is to predict the interior climate of an automobile using advanced computational fluid dynamic (CFD) methods. The development of these advanced prediction tools will enable better selection of engine and accessory components. The goal of this investigation was to predict methods used by the automotive industry. To accomplish this task three separate experiments were performed. The first was a laboratory setup where laser velocimeter (LV) flow field measurements were made in the heating and air conditioning unit of a Ford Windstar. The second involved flow field measurements in the engine compartment of a Ford Explorer, with the engine running idle. The third mapped the flow field exiting the center dashboard panel vent inside the Explorer, while the circulating fan operated at 14 volts. All three experiments utilized full-coincidence three-component LV systems. This enabled the mean and fluctuating velocities to be measured along with the Reynolds stress terms.

  15. Skin-Friction Measurements in Incompressible Flow

    NASA Technical Reports Server (NTRS)

    Smith, Donald W.; Walker, John H.

    1959-01-01

    Experiments have been conducted to measure the local surface-shear stress and the average skin-friction coefficient in Incompressible flow for a turbulent boundary layer on a smooth flat plate having zero pressure gradient. Data were obtained for a range of Reynolds numbers from 1 million to 45 million. The local surface-shear stress was measured by a floating-element skin-friction balance and also by a calibrated total head tube located on the surface of the test wall. The average skin-friction coefficient was obtained from boundary-layer velocity profiles.

  16. Flow in a differentially rotated cylindrical drop at moderate Reynolds number

    NASA Astrophysics Data System (ADS)

    Harriott, G. M.; Brown, R. A.

    1984-07-01

    Galerkin finite-element approximations are combined with computer-implemented perturbation methods for tracking families of solutions to calculate the steady axisymmetric flows in a differentially rotated cylindrical drop as a function of Reynolds number Re, drop aspect ratio and the rotation ratio between the two end disks. The flows for Reynolds numbers below 100 are primarily viscous and reasonably described by an asymptotic analysis. When the disks are exactly counter-rotated, multiple steady flows are calculated that bifurcate to higher values of Re from the expected solution with two identical secondary cells stacked symmetrically about the axial midplane. The new flows have two cells of different size and are stable beyond the critical value Re sub c. The slope of the locus of Re sub c for drops with aspect ratio up to 3 disagrees with the result for two disks of infinite radius computed assuming the similarity form of the velocity field. Changing the rotation ratio for exact counter-rotation ruptures the junction of the multiple flow fields into two separated flow families.

  17. On the Scaling of Small, Heat Simulated Jet Noise Measurements to Moderate Size Exhaust Jets

    NASA Technical Reports Server (NTRS)

    McLaughlin, Dennis K.; Bridges, James; Kuo, Ching-Wen

    2010-01-01

    Modern military aircraft jet engines are designed with variable geometry nozzles to provide optimum thrust in different operating conditions, depending on the flight envelope. However, the acoustic measurements for such nozzles are scarce, due to the cost involved in making full scale measurements and the lack of details about the exact geometry of these nozzles. Thus the present effort at The Pennsylvania State University and the NASA Glenn Research Center- in partnership with GE Aviation is aiming to study and characterize the acoustic field produced by supersonic jets issuing from converging-diverging military style nozzles. An equally important objective is to validate methodology for using data obtained from small and moderate scale experiments to reliably predict the most important components of full scale engine noise. The experimental results presented show reasonable agreement between small scale and moderate scale jet acoustic data, as well as between heated jets and heat-simulated ones. Unresolved issues however are identified that are currently receiving our attention, in particular the effect of the small bypass ratio airflow. Future activities will identify and test promising noise reduction techniques in an effort to predict how well such concepts will work with full scale engines in flight conditions.

  18. Measurement of Liver Blood Flow: A Review

    PubMed Central

    Stansby, G. P.; Hobbs, K. E. F.; Hawkes, D. J.; Colchester, A. C. F.

    1991-01-01

    The study of hepatic haemodynamics is of importance in understanding both hepatic physiology and disease processes as well as assessing the effects of portosystemic shunting and liver transplantation. The liver has the most complicated circulation of any organ and many physiological and pathological processes can affect it1,2. This review surveys the methods available for assessing liver blood flow, examines the different parameters being measured and outlines problems of applicability and interpretation for each technique. The classification of these techniques is to some extent arbitrary and several so called “different” methods may share certain common principles. The methods reviewed have been classified into two groups (Table 1): those primarily reflecting flow through discrete vessels or to the whole organ and those used to assess local microcirculatory blood flow. All techniques have their advantages and disadvantages and in some situations a combination may provide the most information. In addition, because of the many factors affecting liver blood flow and sinusoidal perfusion, readings in a single subject may vary depending on positioning, recent food intake, anxiety, anaesthesia and drug therapy. This must be borne in mind if different studies are to be meaningfully compared. PMID:1931785

  19. Flow Structure on a Delta Wing of Moderate Sweep Angle During and After Pitch-Up Maneuver

    NASA Astrophysics Data System (ADS)

    Celik, Alper; Ozturk, Ilhan; Tunc, Habib Can; Yavuz, Mehmet Metin

    2012-11-01

    The flow structure over a moderate sweep angle delta wing is investigated during and after the pitch-up maneuver and compared to the corresponding stationary wing results. The effects of pitch-up rate and Reynolds number on flow structures and their transformations are also studied. Dye visualization is used for qualitative studies and particle image velocimetry is used for quantitative analysis. At early stages of the maneuver the transformation of flow is initiated by the intertwinement of the dual vortex structure. Increasing the angle of attack results in disappearance of the vortex located closest to the leading-edge of the wing which results in a single, large scale, leading-edge vortex that undergoes a distinctive form of breakdown. It is found that the motion of the wing creates a significant time lag on the development of the flow pattern, when compared to stationary wing. In the relaxation period, the vorticity concentrations become more diffuse and elongated as they move towards the plane of symmetry, and away from the surface of the wing. All these features and transformations occur irrespective of values of pitch rates and Reynold's number. On the other hand, it is seen that the lag of flow pattern is a function of pitch rate and Reynold's number.

  20. Moderate exercise training promotes adaptations in coronary blood flow and adenosine production in normotensive rats

    PubMed Central

    Roque, Fernanda R.; Soci, Ursula Paula Renó; De Angelis, Katia; Coelho, Marcele A.; Furstenau, Cristina R.; Vassallo, Dalton V.; Irigoyen, Maria Claudia; Oliveira, Edilamar M.

    2011-01-01

    OBJECTIVES: Aerobic exercise training prevents cardiovascular risks. Regular exercise promotes functional and structural adaptations that are associated with several cardiovascular benefits. The aim of this study is to investigate the effects of swimming training on coronary blood flow, adenosine production and cardiac capillaries in normotensive rats. METHODS: Wistar rats were randomly divided into two groups: control (C) and trained (T). An exercise protocol was performed for 10 weeks and 60 min/day with a tail overload of 5% bodyweight. Coronary blood flow was quantified with a color microsphere technique, and cardiac capillaries were quantified using light microscopy. Adenine nucleotide hydrolysis was evaluated by enzymatic activity, and protein expression was evaluated by western blot. The results are presented as the means ± SEMs (p<0.05). RESULTS: Exercise training increased the coronary blood flow and the myocardial capillary-to-fiber ratio. Moreover, the circulating and cardiac extracellular adenine nucleotide hydrolysis was higher in the trained rats than in the sedentary rats due to the increased activity and protein expression of enzymes, such as E-NTPDase and 5′-nucleotidase. CONCLUSIONS: Swimming training increases coronary blood flow, number of cardiac capillaries, and adenine nucleotide hydrolysis. Increased adenosine production may be an important contributor to the enhanced coronary blood flow and angiogenesis that were observed in the exercise-trained rats; collectively, these results suggest improved myocardial perfusion. PMID:22189737

  1. Moderately converging ion and electron flows in two-dimensional diodes

    SciTech Connect

    Cavenago, M.

    2012-11-15

    Flow of particles in diodes is solved selfconsistently assuming an approximated system of flow lines, that can be easily represented by an analytic transformation in a complex plane, with assumed uniformity in the third spatial direction. Beam current compression is tunable by an angle parameter {alpha}{sub 0}; transformed coordinate lines are circular arcs, exactly matching to the curved cathode usually considered by rectilinear converging flows. The curvature of flow lines allows to partly balance the transverse effect of space charge. A self-contained discussion of the whole theory is reported, ranging from analytical solution for selfconsistent potential to electrode drawing to precise numerical simulation, which serves as a verification and as an illustration of typical electrode shapes. Motion and Poisson equation are written in a curved flow line system and their approximate consistency is shown to imply an ordinary differential equation for the beam edge potential. Transformations of this equation and their series solutions are given and discussed, showing that beam edge potential has a maximum, so supporting both diode (with {alpha}{sub 0}{approx_equal}{pi}/3) and triode design. Numerical simulations confirm the consistency of these solution. Geometrical details of diode design are discussed: the condition of a zero divergence beam, with the necessary anode lens effect included, is written and solved, as a function of beam compression; accurate relations for diode parameters and perveance are given. Weakly relativistic effects including self-magnetic field are finally discussed as a refinement.

  2. 40 CFR 89.415 - Fuel flow measurement specifications.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 21 2013-07-01 2013-07-01 false Fuel flow measurement specifications... Emission Test Procedures § 89.415 Fuel flow measurement specifications. The fuel flow rate measurement instrument must have a minimum accuracy of 2 percent of the engine maximum fuel flow rate. The...

  3. 40 CFR 89.415 - Fuel flow measurement specifications.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 20 2011-07-01 2011-07-01 false Fuel flow measurement specifications... Emission Test Procedures § 89.415 Fuel flow measurement specifications. The fuel flow rate measurement instrument must have a minimum accuracy of 2 percent of the engine maximum fuel flow rate. The...

  4. 40 CFR 89.415 - Fuel flow measurement specifications.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 21 2012-07-01 2012-07-01 false Fuel flow measurement specifications... Emission Test Procedures § 89.415 Fuel flow measurement specifications. The fuel flow rate measurement... parameters are the elapsed time measurement of the event and the weight or volume measurement....

  5. 40 CFR 89.415 - Fuel flow measurement specifications.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Fuel flow measurement specifications... Emission Test Procedures § 89.415 Fuel flow measurement specifications. The fuel flow rate measurement... parameters are the elapsed time measurement of the event and the weight or volume measurement....

  6. 40 CFR 86.314-79 - Fuel flow measurement specifications.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... percent of the measuring weight. (3) If the mass of fuel consumed is measured electronically (load cell... 40 Protection of Environment 18 2011-07-01 2011-07-01 false Fuel flow measurement specifications....314-79 Fuel flow measurement specifications. (a) The fuel flow rate measurement instrument must have...

  7. Heavy and moderate interval exercise training alters low-flow-mediated constriction but does not increase circulating progenitor cells in healthy humans.

    PubMed

    Rakobowchuk, Mark; Harris, Emma; Taylor, Annabelle; Baliga, Vivek; Cubbon, Richard M; Rossiter, Harry B; Birch, Karen M

    2012-03-01

    Moderate-intensity endurance exercise training improves vascular endothelial vasomotor function; however, the impact of high-intensity exercise training has been equivocal. Thus, the effect of the physiological stress of the exercise remains poorly understood. Furthermore, enhanced vascular repair mediated by circulating progenitor cells may also be improved. To address whether the physiological stress of exercise training is an important factor contributing to these adaptations, 20 healthy participants trained for 6 weeks. Training involved either moderate (MSIT; n = 9) or heavy metabolic stress (HSIT; n = 11) interval exercise training programmes matched for total work and duration of exercise. Before and after training, flow-mediated dilatation, low-flow-mediated constriction and total vessel reactivity were measured at the brachial artery using Doppler ultrasound. Circulating progenitor cells (CD34(+), CD133(+) and CD309/KDR(+)) were measured by flow cytometry (means ± SD). Relative (MSIT pre- 5.5 ± 3.4 versus post-training 6.6 ± 2.5%; HSIT pre- 6.6 ± 4.1 versus post-training 7.0 ± 3.4%, P = 0.33) and normalized (P = 0.16) flow-mediated dilatation did not increase with either training programme. However, low-flow-mediated constriction was greater after training in both groups (MSIT pre- -0.5 ± 3.2 versus post-training -1.9 ± 3.1%; HSIT pre- -1.0 ± 1.7 versus post-training -2.9 ± 3.0%, P = 0.04) and contributed to greater total vessel reactivity (MSIT pre- 7.4 ± 3.3 versus post-training 10.1 ± 3.7%; HSIT pre- 10.9 ± 5.9 versus post-training 12.7 ± 6.2%, P = 0.01). Peak reactive hyperaemia and the area under the shear rate curve were not different between groups, either before or after training. Although circulating progenitor cell numbers increased following heavy-intensity interval exercise training, variability was great amongst participants [MSIT pre- 16 ± 18 versus post-training 14 ± 12 cells (ml whole blood)(-1); HSIT pre- 8 ± 6 versus post

  8. Mesoscale meteorological measurements characterizing complex flows

    SciTech Connect

    Hubbe, J.M.; Allwine, K.J.

    1993-09-01

    Meteorological measurements are an integral and essential component of any emergency response system for addressing accidental releases from nuclear facilities. An important element of the US Department of Energy`s (DOE`s) Atmospheric Studies in Complex Terrain (ASCOT) program is the refinement and use of state-of-the-art meteorological instrumentation. ASCOT is currently making use of ground-based remote wind sensing instruments such as doppler acoustic sounders (sodars). These instruments are capable of continuously and reliably measuring winds up to several hundred meters above the ground, unattended. Two sodars are currently measuring the winds, as part of ASCOT`s Front Range Study, in the vicinity of DOE`s Rocky Flats Plant (RFP) near Boulder, Colorado. A brief description of ASCOT`s ongoing Front Range Study is given followed by a case study analysis that demonstrates the utility of the meteorological measurement equipment and the complexity of flow phenomena that are experienced near RFP. These complex flow phenomena can significantly influence the transport of the released material and consequently need to be identified for accurate assessments of the consequences of a release.

  9. Holocinematographic velocimetry - Resolution limitation for flow measurement

    NASA Astrophysics Data System (ADS)

    Liburdy, James A.

    1987-10-01

    The goal of developing a holocinematographic velocimeter (HCV) is to provide a technique to study the evolution of instantaneous three-dimensional velocity profiles in turbulent flow fields. The method tracks individual seed particles that have been introduced into the flow. An imaging system using far-field holography is used to provide a full field of view tracking. Velocity information is determined from measured particle displacements of sequential hologram reconstruction. This study examines the resolution limits of far-field holography as applied to the HCV. The results aid in the determination of required seeding concentrations, establish the ability to resolve particle centers, and illustrate the use of a dual TV camera system to aid resolution. A straightforward enhancement technique provides a means to eliminate noise and reduce out of image plane ambiguity.

  10. Flow Measurement by Means of Light Interference

    NASA Technical Reports Server (NTRS)

    Zobel, Th.

    1949-01-01

    There has been under development for the high-speed wind tunnel of the LFA an optical measuring arrangement for the qualitative and quantitative investigation of flow. By the use of interference measurements, the determination of density at the surface of the bodies being tested in the air stream and in the vicinity of these bodies can be undertaken. The results obtained so far in the simple preliminary investigations show that it is possible, even at a low Reynolds number, to obtain the density field in the neighborhood of a test body by optical means. Simple analytical expressions give the relation between density, pressure, velocity, and temperature. In addition to this, the interference measurement furnishes valuable data on the state of the boundary layer, that is, the sort of boundary layer (whether laminar or turbulent), as well as the temperature and velocity distribution.

  11. Rectangular subsonic jet flow field measurements

    NASA Technical Reports Server (NTRS)

    Morrison, Gerald L.; Swan, David H.

    1989-01-01

    Flow field measurements are presented of 3 subsonic rectangular cold air jets. The 3 cases presented had aspect ratios of 1 x 2, 1 x 4 at a Mach number of 0.09 and an aspect ratio of 1 x 2 at a Mach number of 0.9. All measurements were made using a 3-D laser Doppler anemoneter system. The presented data includes the mean velocity vector, all Reynolds stress tensor components, turbulent kinetic energy and velocity correlation coefficients. The data is presented in tabular and graphical form. No analysis of the measured data or comparison to other published data is made. All tabular data are available in ASCII format on MS-DOS compatible disks.

  12. Fluorescence lifetime measurements in flow cytometry

    NASA Astrophysics Data System (ADS)

    Beisker, Wolfgang; Klocke, Axel

    1997-05-01

    Fluorescence lifetime measurements provide insights int eh dynamic and structural properties of dyes and their micro- environment. The implementation of fluorescence lifetime measurements in flow cytometric systems allows to monitor large cell and particle populations with high statistical significance. In our system, a modulated laser beam is used for excitation and the phase shift of the fluorescence signal recorded with a fast computer controlled digital oscilloscope is processed digitally to determine the phase shift with respect to a reference beam by fast fourier transform. Total fluorescence intensity as well as other parameters can be determined simultaneously from the same fluorescence signal. We use the epi-illumination design to allow the use of high numerical apertures to collect as much light as possible to ensure detection of even weak fluorescence. Data storage and processing is done comparable to slit-scan flow cytometric data using data analysis system. The results are stored, displayed, combined with other parameters and analyzed as normal listmode data. In our report we discuss carefully the signal to noise ratio for analog and digital processed lifetime signals to evaluate the theoretical minimum fluorescence intensity for lifetime measurements. Applications to be presented include DNA staining, parameters of cell functions as well as different applications in non-mammalian cells such as algae.

  13. Turbulence measurements in high-speed flows by resonant fluoresence

    NASA Technical Reports Server (NTRS)

    Miles, R. B.

    1982-01-01

    Both mean flow and turbulence measurements were investigated using the resonant Doppler velocimeter in a Mach 3.2 nitrogen flow. Data are presented showing velocity, temperature and pressure measured point by point across the flow field. This data is compared with conventional pitot and temperature surveys. Turbulence was induced by a small metal tab in the flow and observed by both hot wire and RDV techniques. Photographs of the flow field demonstrate the utility of the RDV for quantitative flow field visualization.

  14. A tool for obtaining oriented samples of weakly to moderately indurated sedimentary rocks for paleomagnetic measurements

    NASA Astrophysics Data System (ADS)

    Lerbekmo, J. F.

    1990-03-01

    The tool is designed to take 1 inch (2.5 cm) diameter cores up to 2 inches (5 cm) in length in sedimentary rocks of moderate induration that cannot normally be sampled by traditional methods. A stainless steel core-barrel with internal scriber is hammered vertically into the rock and twisted out. The core-barrel is attached to an extruder which also holds a plastic bottle. The core is screwed out of the core-barrel directly into the bottle of the same internal diameter. The vial is later cut to an acceptable length for the magnetometer and sealed with a plastic cap. Inasmuch as the sample is never removed from the plastic bottle, fractured and bentonitic rocks which cannot be sampled by means of hand-blocks or by diamond-drilling, can be magnetically measured.

  15. 40 CFR 86.314-79 - Fuel flow measurement specifications.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 18 2010-07-01 2010-07-01 false Fuel flow measurement specifications....314-79 Fuel flow measurement specifications. (a) The fuel flow rate measurement instrument must have a... period of the clock. (2) For Diesel engines only, if the mass of fuel consumed is measured by...

  16. 40 CFR 86.314-79 - Fuel flow measurement specifications.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 19 2012-07-01 2012-07-01 false Fuel flow measurement specifications....314-79 Fuel flow measurement specifications. (a) The fuel flow rate measurement instrument must have a... period of the clock. (2) For Diesel engines only, if the mass of fuel consumed is measured by...

  17. 40 CFR 92.107 - Fuel flow measurement.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Fuel flow measurement. 92.107 Section... measurement. (a) Fuel flow measurement for locomotive and engine testing. The rate of fuel consumption by the engine must be measured with equipment conforming to the following: (1) The fuel flow rate...

  18. 40 CFR 89.414 - Air flow measurement specifications.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 20 2014-07-01 2013-07-01 true Air flow measurement specifications. 89... Test Procedures § 89.414 Air flow measurement specifications. (a) The air flow measurement method used... during the test. Overall measurement accuracy must be ± 2 percent of the maximum engine value for...

  19. 40 CFR 92.107 - Fuel flow measurement.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 21 2012-07-01 2012-07-01 false Fuel flow measurement. 92.107 Section... measurement. (a) Fuel flow measurement for locomotive and engine testing. The rate of fuel consumption by the engine must be measured with equipment conforming to the following: (1) The fuel flow rate...

  20. 40 CFR 89.414 - Air flow measurement specifications.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 21 2013-07-01 2013-07-01 false Air flow measurement specifications... Emission Test Procedures § 89.414 Air flow measurement specifications. (a) The air flow measurement method... during the test. Overall measurement accuracy must be ± 2 percent of the maximum engine value for...

  1. 40 CFR 89.414 - Air flow measurement specifications.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 21 2012-07-01 2012-07-01 false Air flow measurement specifications... Emission Test Procedures § 89.414 Air flow measurement specifications. (a) The air flow measurement method... during the test. Overall measurement accuracy must be ± 2 percent of the maximum engine value for...

  2. 40 CFR 90.416 - Intake air flow measurement specifications.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Intake air flow measurement... Gaseous Exhaust Test Procedures § 90.416 Intake air flow measurement specifications. (a) If used, the engine intake air flow measurement method used must have a range large enough to accurately measure...

  3. Flow cytometer measurement of binding assays

    DOEpatents

    Saunders, George C.

    1987-01-01

    A method of measuring the result of a binding assay that does not require separation of fluorescent smaller particles is disclosed. In a competitive binding assay the smaller fluorescent particles coated with antigen compete with antigen in the sample being analyzed for available binding sites on larger particles. In a sandwich assay, the smaller, fluorescent spheres coated with antibody attach themselves to molecules containing antigen that are attached to larger spheres coated with the same antibody. The separation of unattached, fluorescent smaller particles is made unnecessary by only counting the fluorescent events triggered by the laser of a flow cytometer when the event is caused by a particle with a light scatter measurement within a certain range corresponding to the presence of larger particles.

  4. Meteorological insights from planetary heat flow measurements

    NASA Astrophysics Data System (ADS)

    Lorenz, Ralph D.

    2015-04-01

    Planetary heat flow measurements are made with a series of high-precision temperature sensors deployed in a column of regolith to determine the geothermal gradient. Such sensors may, however, be susceptible to other influences, especially on worlds with atmospheres. First, pressure fluctuations at the surface may pump air in and out of pore space leading to observable, and otherwise unexpected, temperature fluctuations at depth. Such pumping is important in subsurface radon and methane transport on Earth: evidence of such pumping may inform understanding of methane or water vapor transport on Mars. Second, the subsurface profile contains a muted record of surface temperature history, and such measurements on other worlds may help constrain the extent to which Earth's Little Ice Age was directly solar-forced, versus volcanic-driven and/or amplified by climate feedbacks.

  5. Method and Apparatus for Measuring Fluid Flow

    NASA Technical Reports Server (NTRS)

    Arndt, G. Dickey (Inventor); Nguyen, Thanh X. (Inventor); Carl, James R. (Inventor)

    1997-01-01

    Method and apparatus for making measurements on fluids related to their complex permeability are disclosed. A microwave probe is provided for exposure to the fluids. The probe can be non-intrusive or can also be positioned at the location where measurements are to be made. The impedance of the probe is determined. in part. by the complex dielectric constant of the fluids at the probe. A radio frequency signal is transmitted to the probe and the reflected signal is phase and amplitude detected at a rapid rate for the purpose of identifying the fluids. Multiple probes may be selectively positioned to monitor the behavior of the fluids including their flow rate. Fluids may be identified as between two or more different fluids as well as multiple phases of the same fluid based on differences between their complex permittivities.

  6. Transcutaneous measurement of volume blood flow

    NASA Technical Reports Server (NTRS)

    Daigle, R. E.; Mcleod, F. D.; Miller, C. W.; Histand, M. B.; Wells, M. K.

    1974-01-01

    Blood flow velocity measurements, using Doppler velocimeter, are described. The ability to measure blood velocity using ultrasound is derived from the Doppler effect; the change in frequency which occurs when sound is reflected or transmitted from a moving target. When ultrasound of the appropriate frequency is transmitted through a moving blood stream, the blood cells act as point scatterers of ultrasonic energy. If this scattered ultrasonic energy is detected, it is found to be shifted in frequency according to the velocity of the blood cells, nu, the frequency of the incident sound, f sub o, the speed of sound in the medium, c, and the angle between the sound beam and the velocity vector, o. The relation describing this effect is known as the Doppler equation. Delta f = 2 f sub o x nu x cos alpha/c. The theoretical and experimental methods are evaluated.

  7. Improved flow cytometer measurement of binding assays

    NASA Astrophysics Data System (ADS)

    Saunders, G. C.

    1984-05-01

    A method of measuring binding assays is carried out with different size particles wherein the binding assay sample is run through a flow cytometer without separating the sample from the marking agent. The amount of a binding reactant present in a sample is determined by providing particles with a coating of binder and also known quantity of smaller particles with a coating of binder reactant. The smaller particles also contain a fluorescent chemical. The particles are combined with the sample and the binding reaction is allowed to occur for a set length of time followed by combining the smaller particles with the mixture of the particles and the sample produced and allowing the binding reactions to proceed to equilibrium. The fluorescence and light scatter of the combined mixture is then measured as the combined mixture passes through a flow cytometer equipped with a laser to bring about fluorescence, and the number of fluorescent events are compared. A similar method is also provided for determining the amount of antigen present in the sample by providing spheres with an antibody coating and some smaller spheres with an antigen coating.

  8. Improved flow cytometer measurement of binding assays

    DOEpatents

    Saunders, G.C.

    1984-05-30

    The invention relates to a method of measuring binding assays carried out with different size particles wherein the binding assay sample is run through a flow cytometer without separating the sample from the marking agent. The amount of a binding reactant present in a sample is determined by providing particles with a coating of binder and also a known quantity of smaller particles with a coating of binder reactant. The binding reactant is the same as the binding reactant present in the sample. The smaller particles also contain a fluorescent chemical. The particles are combined with the sample and the binding reaction is allowed to occur for a set length of time followed by combining the smaller particles with the mixture of the particles and the sample produced and allowing the binding reactions to proceed to equilibrium. The fluorescence and light scatter of the combined mixture is then measured as the combined mixture passes through a flow cytometer equipped with a laser to bring about fluorescence, and the number and strength of fluorescent events are compared. A similar method is also provided for determining the amount of antigen present in the sample by providing spheres with an antibody coating and some smaller spheres with an antigen coating. (LEW)

  9. Inertial effects at moderate Reynolds number in thin-film rimming flows driven by surface shear

    NASA Astrophysics Data System (ADS)

    Kay, E. D.; Hibberd, S.; Power, H.

    2013-10-01

    In this paper, we study two-dimensional thin-film flow inside a stationary circular cylinder driven by an imposed surface shear stress. Modelling is motivated by a need to understand the cooling and film dynamics provided by oil films in an aero-engine bearing chamber characterised by conditions of very high surface shear and additional film mass flux from oil droplets entering the film through the surface. In typical high-speed operation, film inertial effects can provide a significant leading-order mechanism neglected in existing lubrication theory models. Inertia at leading-order is included within a depth-averaged formulation where wall friction is evaluated similar to hydraulic models. This allows key nonlinear inertial effects to be included while retaining the ability to analyse the problem in a mathematically tractable formulation and compare with other approaches. In constructing this model, a set of simplified mass and momentum equations are integrated through the depth of the film yielding a spatially one-dimensional depth-averaged formulation of the problem. An a priori assumed form of velocity profile is needed to complete the system. In a local Stokes flow analysis, a quadratic profile is the exact solution for the velocity field though it must be modified when inertial effects become important. Extension of the velocity profile to a cubic profile is selected enabling specification of a wall friction model to include the roughness of the cylinder wall. A modelling advantage of including the inertia term, relevant to the applications considered, is that a smooth progression in solution can be obtained between cases of low Reynolds number corresponding to lubrication theory, and high Reynolds number corresponding to uniform rimming-flow. Importantly, we also investigate the effect of inertia on some typical solutions from other studies and present a greater insight to existing and new film solutions which arise from including inertia effects.

  10. Method and Apparatus for Measuring Fluid Flow

    NASA Technical Reports Server (NTRS)

    Arndt, G. Dickey (Inventor); Nguyen, Than X. (Inventor); Carl, James R. (Inventor)

    1995-01-01

    The invention is a method and apparatus for monitoring the presence, concentration, and the movement of fluids. It is based on utilizing electromagnetic measurements of the complex permittivity of the fluids for detecting and monitoring the fluid. More particularly the apparatus uses one or more microwave probes which are placed at the locations where the measurements are to be made. A radio frequency signal is transmitted to the probe and the reflected signal is phase and amplitude detected at a rapid rate for the purpose of identifying the fluids, based on their dielectric constant at the probe. The apparatus can be used for multiple purposes including measures of flow rates, turbulence, dispersion, fluid identification, and changes in flow conditions of multiple fluids or multiple states of a single fluid in a flowline or a holding container. The apparatus includes a probe consisting of two electrical conductors separated by an insulator. A radio frequency signal is communicated to the probe and is reflected back from the portion of the probe exposed to the fluid. The radio frequency signal also provides a reference signal. An oscillator generates a second signal which combined with each of the reference signal and the reflected signal to produce signals of lower frequencies to facilitate filtering and amplifying those signals. The two signals are then mixed in a detector to produce an output signal that is representative of the phase and amplitude change caused by the reflection of the signal at the probe exposed to the fluid. The detector may be a dual phase detector that provides two such output signals that are in phase quadrature. A phase shifter may be provided for selectively changing the phase of the reference signal to improve the sensitivity of at least one of the output signals for more accurate readings and/or for calibration purposes. The two outputs that are in quadrature with respect to each other may be simultaneously monitored to account for

  11. Measurement of gas flow at extremely low pressures

    NASA Technical Reports Server (NTRS)

    Bitterly, J. G.

    1969-01-01

    Method accurately measures the flow of gases produced by evaporation or sublimation at pressures approaching total vacuum. Measurement of heat rejection in terms of flow of steam is taken with water as the liquid undergoing change in phase.

  12. Method and apparatus for measuring flow velocity using matched filters

    DOEpatents

    Raptis, Apostolos C.

    1983-01-01

    An apparatus and method for measuring the flow velocities of individual phase flow components of a multiphase flow utilizes matched filters. Signals arising from flow noise disturbance are extracted from the flow, at upstream and downstream locations. The signals are processed through pairs of matched filters which are matched to the flow disturbance frequency characteristics of the phase flow component to be measured. The processed signals are then cross-correlated to determine the transit delay time of the phase flow component between sensing positions.

  13. Method and apparatus for measuring flow velocity using matched filters

    DOEpatents

    Raptis, A.C.

    1983-09-06

    An apparatus and method for measuring the flow velocities of individual phase flow components of a multiphase flow utilizes matched filters. Signals arising from flow noise disturbance are extracted from the flow, at upstream and downstream locations. The signals are processed through pairs of matched filters which are matched to the flow disturbance frequency characteristics of the phase flow component to be measured. The processed signals are then cross-correlated to determine the transit delay time of the phase flow component between sensing positions. 8 figs.

  14. Quantitative analysis of the angular dynamics of a single spheroid in simple shear flow at moderate Reynolds numbers

    NASA Astrophysics Data System (ADS)

    Rosén, Tomas; Nordmark, Arne; Aidun, Cyrus K.; Do-Quang, Minh; Lundell, Fredrik

    2016-08-01

    A spheroidal particle in simple shear flow shows surprisingly complicated angular dynamics; caused by effects of fluid inertia (characterized by the particle Reynolds number Rep) and particle inertia (characterized by the Stokes number St). Understanding this behavior can provide important fundamental knowledge of suspension flows with spheroidal particles. Up to now only qualitative analysis has been available at moderate Rep. Rigorous analytical methods apply only to very small Rep and numerical results lack accuracy due to the difficulty in treating the moving boundary of the particle. Here we show that the dynamics of the rotational motion of a prolate spheroidal particle in a linear shear flow can be quantitatively analyzed through the eigenvalues of the log-rolling particle (particle aligned with vorticity). This analysis provides an accurate description of stable rotational states in terms of Rep,St, and particle aspect ratio (rp). Furthermore we find that the effect on the orientational dynamics from fluid inertia can be modeled with a Duffing-Van der Pol oscillator. This opens up the possibility of developing a reduced-order model that takes into account effects from both fluid and particle inertia.

  15. Inertial migration of spherical particles in circular Poiseuille flow at moderately high Reynolds numbers

    NASA Astrophysics Data System (ADS)

    Shao, Xueming; Yu, Zhaosheng; Sun, Bo

    2008-10-01

    The inertial migration of spherical particles in a circular Poiseuille flow is numerically investigated for the tube Reynolds number up to 2200. The periodic boundary condition is imposed in the streamwise direction. The equilibrium positions, the migration velocity, and the angular velocity of a single particle in a tube cell are examined at different Reynolds numbers, particle-tube size ratios, and tube lengths. Inner equilibrium positions are observed as the Reynolds number exceeds a critical value, in qualitatively agreement with the previous experimental observations [J.-P. Matas, J. F. Morris, and E. Guazzelli, J. Fluid Mech. 515, 171 (2004)]. Our results indicate that the hydrodynamic interactions between the particles in different periodic cells have significant effects on the migration of the particles at the tube length being even as large as 6.7 particle diameters and they tend to stabilize the particles at the outer Segré-Silberberg equilibrium positions and to suppress the emergence of the inner equilibrium positions. A mirror-symmetric traveling-wave-like structure is observed when the particle Reynolds number is large enough. A pair of counter-rotating streamwise vortices exists at both upstream and downstream of the particle but with different rotating directions. The fluids in the half of the pipe without the particle flow more slowly and most fluids in the other half with the particle move faster with respect to the parabolic profile. The intensity of the structure is influenced by the local particle Reynolds number, the particle motion, and the tube length. In addition, the migration of multiple particles in a periodic tube cell is examined. We attribute the disparity in the critical particle Reynolds number for the occurrence of the inner particle annulus for the experiments and our simulations to the effect of the tube length or the periodic boundary condition in our numerical model.

  16. Novel laser Doppler flowmeter for pulpal blood flow measurements

    NASA Astrophysics Data System (ADS)

    Zang, De Yu; Millerd, James E.; Wilder-Smith, Petra B. B.; Arrastia-Jitosho, Anna-Marie A.

    1996-04-01

    We have proposed and experimentally demonstrated a new configuration of laser Doppler flowmetry for dental pulpal blood flow measurements. To date, the vitality of a tooth can be determined only by subjective thermal or electric tests, which are of questionable reliability and may induced pain in patient. Non-invasive techniques for determining pulpal vascular reactions to injury, treatment, and medication are in great demand. The laser Doppler flowmetry technique is non-invasive; however, clinical studies have shown that when used to measure pulpal blood flow the conventional back-scattering Doppler method suffers from low signal-to-noise ratio (SNR) and unreliable flux readings rendering it impossible to calibrate. A simplified theoretical model indicates that by using a forward scattered geometry the detected signal has a much higher SNR and can be calibrated. The forward scattered signal is readily detectable due to the fact that teeth are relatively thin organs with moderate optical loss. A preliminary experiment comparing forward scattered detection with conventional back- scattered detection was carried out using an extracted human molar. The results validated the findings of the simple theoretical model and clearly showed the utility of the forward scattering geometry. The back-scattering method had readings that fluctuated by as much as 187% in response to small changes in sensor position relative to the tooth. The forward scattered method had consistent readings (within 10%) that were independent of the sensor position, a signal-to-noise ratio that was at least 5.6 times higher than the back-scattering method, and a linear response to flow rate.

  17. Measuring vortical flows in the solar interior

    NASA Astrophysics Data System (ADS)

    Langfellner, Jan

    2015-09-01

    This thesis focuses on observations of the effects of rotation on solar convection at the length scales of supergranulation and larger (>30 Mm). Rotation drives vortical flows through the Coriolis force and causes anisotropic velocity correlations that are believed to influence the large-scale solar dynamics. We obtain horizontal flows using photospheric Doppler velocity and continuum intensity images from the Helioseismic and Magnetic Imager (HMI) onboard the Solar Dynamics Observatory (SDO) spacecraft via the techniques of time-distance helioseismology (TD) and local correlation tracking (LCT) of granules. In time-distance helioseismology, the local vertical vorticity can be measured by taking the difference between wave travel times measured in the anti-clockwise and clockwise directions along a closed contour. The agreement between the TD and LCT methods is excellent up to ±60° latitude, provided that a center-to-limb correction is applied. Averaging over longitude, one finds that there is a small but significant correlation between the horizontal divergence and the vertical vorticity component of supergranular flows away from the solar equator. By comparison to a noise model, we find that the TD technique can be used to probe the vertical vorticity of flows on spatial scales larger than about 15 Mm, thus including supergranules and also giant cells. We also find that the vertical vorticity signal is much easier to measure using SDO/HMI observations than previous observations. The impact of the Sun's rotation on supergranulation is studied in detail by making spatial maps of the vertical vorticity of the flows associated with the average supergranule. The average supergranule is constructed by co-aligning thousands of individual supergranules in a given latitude band. For the first time, we are able to spatially resolve vorticity associated with inflows and outflow regions. In the northern hemisphere, outflows are on average associated with a clockwise

  18. Measuring ice and liquid water content in moderately supercooled clouds with Cloudnet

    NASA Astrophysics Data System (ADS)

    Bühl, Johannes; Seifert, Patric; Myagkov, Alexander; Albert, Ansmann

    2016-04-01

    The interaction between ice nuclei and clouds is an important topic in weather and climate research. Recent laboratory experiments and field in-situ field campaigns present more and more detailed measurements of ice nucleating particles (INP) at temperatures close to 0°C. This brings moderately supercooled mixed-phase clouds into the focus of current cloud research. One current example is the European Union BACCHUS project. A major goal of BACCHUS is the analysis of the anthropogenic impact on ice nucleation. Within this project, we use the Leipzig Aerosol Cloud Remote Observations System (LACROS) and the Cloudnet framework in order to get quantitative insight into the formation of ice in mixed-phase layered clouds with cloud top temperature (CTT) from -40 to 0°C. Depolarization measurements from lidar and radar show a clear dependence between particle shape and the temperature under which the particles have been formed. The special focus of this work is on the CTT range from -10 to 0°C. An algorithm is presented to decide between ice and liquid water precipitation falling from the clouds showing that between 10% and 30% of all layered clouds show ice precipitation with CTT between -5 and 0°C. For these slightly supercooled clouds an average ice-water-content between 10e-7 and 10e-8 [kg per cubic meter] is found.

  19. 40 CFR 89.414 - Air flow measurement specifications.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 20 2011-07-01 2011-07-01 false Air flow measurement specifications. 89.414 Section 89.414 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... Emission Test Procedures § 89.414 Air flow measurement specifications. (a) The air flow measurement...

  20. 40 CFR 92.107 - Fuel flow measurement.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 21 2013-07-01 2013-07-01 false Fuel flow measurement. 92.107 Section...) CONTROL OF AIR POLLUTION FROM LOCOMOTIVES AND LOCOMOTIVE ENGINES Test Procedures § 92.107 Fuel flow measurement. (a) Fuel flow measurement for locomotive and engine testing. The rate of fuel consumption by...

  1. 40 CFR 92.107 - Fuel flow measurement.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 20 2011-07-01 2011-07-01 false Fuel flow measurement. 92.107 Section...) CONTROL OF AIR POLLUTION FROM LOCOMOTIVES AND LOCOMOTIVE ENGINES Test Procedures § 92.107 Fuel flow measurement. (a) Fuel flow measurement for locomotive and engine testing. The rate of fuel consumption by...

  2. 40 CFR 89.414 - Air flow measurement specifications.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Air flow measurement specifications. 89.414 Section 89.414 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... Emission Test Procedures § 89.414 Air flow measurement specifications. (a) The air flow measurement...

  3. Ultrasonic fluid flow measurement method and apparatus

    DOEpatents

    Kronberg, J.W.

    1993-10-12

    An apparatus for measuring the flow of a fluid in a pipe using ultrasonic waves. The apparatus comprises an ultrasonic generator, a lens for focusing the sound energy produced by the generator, and means for directing the focused energy into the side of the pipe through an opening and in a direction close to parallel to the long axis of the pipe. A cone carries the sound energy to the lens from the generator. Depending on the choice of materials, there may be a quarter-wave, acoustic impedance matching section between the generator and the cone to reduce the reflections of energy at the cone boundary. The lens material has an acoustic impedance similar to that of the cone material but a different sonic velocity so that the lens can converge the sound waves in the fluid. A transition section between the lens and the fluid helps to couple the energy to the fluid and assures it is directed as close to parallel to the fluid flow direction as possible. 3 figures.

  4. Ultrasonic fluid flow measurement method and apparatus

    DOEpatents

    Kronberg, James W.

    1993-01-01

    An apparatus for measuring the flow of a fluid in a pipe using ultrasonic waves. The apparatus comprises an ultrasonic generator, a lens for focusing the sound energy produced by the generator, and means for directing the focused energy into the side of the pipe through an opening and in a direction close to parallel to the long axis of the pipe. A cone carries the sound energy to the lens from the generator. Depending on the choice of materials, there may be a quarter-wave, acoustic impedance matching section between the generator and the cone to reduce the reflections of energy at the cone boundary. The lens material has an acoustic impedance similar to that of the cone material but a different sonic velocity so that the lens can converge the sound waves in the fluid. A transition section between the lens and the fluid helps to couple the energy to the fluid and assures it is directed as close to parallel to the fluid flow direction as possible.

  5. Transitional flow in the wake of a moderate to large height cylindrical roughness element

    NASA Astrophysics Data System (ADS)

    Plogmann, B.; Würz, W.; Krämer, E.

    2015-12-01

    The effect of an isolated, cylindrical roughness on the stability of an airfoil boundary layer has been studied based on particle image velocimetry and hot-wire anemometry. The investigated roughness elements range from a sub-critical to a super-critical behavior with regard to the critical roughness Reynolds number. For the sub-critical case, the nonlinear disturbance growth in the near wake is governed by oblique Tollmien-Schlichting (TS) type modes. Further downstream, these disturbance modes are, however, damped with the mean flow stabilization and no dominant modes persist in the far wake. By contrast, in the transitional configuration the disturbance growth is increased, but still associated with a TS-type instability in the near-wake centerline region of the low-aspect (height-to-diameter) ratio element. That is, the disturbances in the centerline region show a similar behavior as known for 2D elements, whereas in the outer spanwise domain a Kelvin-Helmholtz (KH) type, shear-layer instability is found, as previously reported for larger aspect ratio isolated elements. With increasing height and, thereby, aspect ratio of the roughness, the KH-type instability domain extends toward the centerline and, accordingly, the TS-type instability domain decreases. For high super-critical cases, transition is already triggered in the wall-normal and spanwise shear layers upstream and around the roughness. In the immediate wake, periodic shear-layer disturbances roll up into a—for isolated elements characteristic—shedding of vortices, which was not present at the lower roughness Reynolds number cases due to the decreased aspect ratio and, thereby, different instability mechanism.

  6. A process-oriented measure of habit strength for moderate-to-vigorous physical activity

    PubMed Central

    Grove, J. Robert; Zillich, Irja; Medic, Nikola

    2014-01-01

    Purpose: Habitual action is an important aspect of health behaviour, but the relevance of various habit strength indicators continues to be debated. This study focused specifically on moderate-to-vigorous physical activity (MVPA) and evaluated the construct validity of a framework emphasizing patterned action, stimulus-response bonding, automaticity, and negative consequences for nonperformance as indicators of habit strength for this form of exercise. Methods: Upper-level undergraduates (N = 124) provided demographic information and responded to questionnaire items assessing historical MVPA involvement, current MVPA involvement, and the four proposed habit strength dimensions. Factor analyses were used to examine the latent structure of the habit strength indicators, and the model's construct validity was evaluated via an examination of relationships with repetition history and current behaviour. Results: At a measurement level, findings indicated that the proposed four-component model possessed psychometric integrity as a coherent set of factors. Criterion-related validity was also demonstrated via significant changes in three of the four factors as a function of past involvement in MVPA and significant correlations with the frequency, duration, and intensity of current MVPA. Conclusions: These findings support the construct validity of this exercise habit strength model and suggest that it could provide a template for future research on how MVPA habits are developed and maintained. PMID:25750789

  7. 40 CFR 90.417 - Fuel flow measurement specifications.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... specifications of 40 CFR part 1065, subpart C, instead of those in this paragraph (b). ... 40 Protection of Environment 21 2013-07-01 2013-07-01 false Fuel flow measurement specifications... Gaseous Exhaust Test Procedures § 90.417 Fuel flow measurement specifications. (a) Fuel flow...

  8. 40 CFR 90.417 - Fuel flow measurement specifications.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... specifications of 40 CFR part 1065, subpart C, instead of those in this paragraph (b). ... 40 Protection of Environment 20 2011-07-01 2011-07-01 false Fuel flow measurement specifications... Gaseous Exhaust Test Procedures § 90.417 Fuel flow measurement specifications. (a) Fuel flow...

  9. 40 CFR 90.417 - Fuel flow measurement specifications.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... specifications of 40 CFR part 1065, subpart C, instead of those in this paragraph (b). ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Fuel flow measurement specifications... Gaseous Exhaust Test Procedures § 90.417 Fuel flow measurement specifications. (a) Fuel flow...

  10. 40 CFR 90.417 - Fuel flow measurement specifications.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... specifications of 40 CFR part 1065, subpart C, instead of those in this paragraph (b). ... 40 Protection of Environment 21 2012-07-01 2012-07-01 false Fuel flow measurement specifications... Gaseous Exhaust Test Procedures § 90.417 Fuel flow measurement specifications. (a) Fuel flow...

  11. Measuring and moderating the water resource impact of biofuel production and trade

    NASA Astrophysics Data System (ADS)

    Fingerman, Kevin Robert

    Energy systems and water resources are inextricably linked, especially in the case of bioenergy, which can require up to three orders of magnitude more water than other energy carriers. Water scarcity already affects about 1 in 5 people globally, and stands to be exacerbated in many locales by current biofuel expansion plans. This dissertation engages with several of the analytical and governance challenges raised by this connection between bioenergy expansion and global water resources. My examination begins with an overview of important concepts in water resource analysis, followed by a review of current literature on the water impacts of most major energy pathways. I then report on a case study of ethanol fuel in California. This work employed a coupled agro-climatic and life cycle assessment (LCA) model to estimate the water resource impacts of several bioenergy expansion scenarios at a county-level resolution. It shows that ethanol production in California regularly consumes more than 1000 gallons of water per gallon of fuel produced, and that 99% of life-cycle water consumption occurs in the feedstock cultivation phase. This analysis then delves into the complexity of life cycle impact assessment for water resources. Despite improvements in water accounting methods, impact assessment must contend with the fact that different water sources are not necessarily commensurable, and that impacts depend on the state of the resource base that is drawn upon. I adapt water footprinting and LCA techniques to the bioenergy context, describing comprehensive inventory approaches and developing a process for characterizing (weighting) consumption values to enable comparison across resource bases. This process draws on metrics of water stress, accounting for environmental flow requirements, climatic variability, and non-linearity of water stress effects. My assessment framework was developed in hopes that it would be useful in managing the risks and impacts it describes. The

  12. Flow studies and particulate collection measurements

    SciTech Connect

    Greiner, G.P.; Furlong, D.A.; Bahner, M.A.

    1990-04-01

    This report describes testing of a Reduced Entrainment electrostatic Precipitator (REP) that has a portion of the main precipitator flow drawn through a porous (fabric) collecting surface. Tests investigated effects of flow through the collecting surface (side flow) on precipitator turbulence and particulate removal efficiency. Testing focused on these effects as being significant to the collection of fine (less than 10 microns) particulate. 17 refs., 41 figs., 10 tabs.

  13. On-Orbit Lunar Modulation Transfer Function Measurements for the Moderate Resolution Imaging Spectroradiometer

    NASA Technical Reports Server (NTRS)

    Choi, Taeyong; Xiong, Xiaoxiong; Wang, Zhipeng

    2013-01-01

    Spatial quality of an imaging sensor can be estimated by evaluating its modulation transfer function (MTF) from many different sources such as a sharp edge, a pulse target, or bar patterns with different spatial frequencies. These well-defined targets are frequently used for prelaunch laboratory tests, providing very reliable and accurate MTF measurements. A laboratory-quality edge input source was included in the spatial-mode operation of the Spectroradiometric Calibration Assembly (SRCA), which is one of the onboard calibrators of the Moderate Resolution Imaging Spectroradiometer (MODIS). Since not all imaging satellites have such an instrument, SRCA MTF estimations can be used as a reference for an on-orbit lunar MTF algorithm and results. In this paper, the prelaunch spatial quality characterization process from the Integrated Alignment Collimator and SRCA is briefly discussed. Based on prelaunch MTF calibration using the SRCA, a lunar MTF algorithm is developed and applied to the lifetime on-orbit Terra and Aqua MODIS lunar collections. In each lunar collection, multiple scan-directionMoon-to-background transition profiles are aligned by the subpixel edge locations from a parametric Fermi function fit. Corresponding accumulated edge profiles are filtered and interpolated to obtain the edge spread function (ESF). The MTF is calculated by applying a Fourier transformation on the line spread function through a simple differentiation of the ESF. The lifetime lunar MTF results are analyzed and filtered by a relationship with the Sun-Earth-MODIS angle. Finally, the filtered lunarMTF values are compared to the SRCA MTF results. This comparison provides the level of accuracy for on-orbit MTF estimations validated through prelaunch SRCA measurements. The lunar MTF values had larger uncertainty than the SRCA MTF results; however, the ratio mean of lunarMTF fit and SRCA MTF values is within 2% in the 250- and 500-m bands. Based on the MTF measurement uncertainty range

  14. Heat transfer analysis for peripheral blood flow measurement system

    NASA Astrophysics Data System (ADS)

    Nagata, Koji; Hattori, Hideharu; Sato, Nobuhiko; Ichige, Yukiko; Kiguchi, Masashi

    2009-06-01

    Some disorders such as circulatory disease and metabolic abnormality cause many problems to peripheral blood flow condition. Therefore, frequent measurement of the blood flow condition is bound to contribute to precaution against those disorders and to control of conditions of the diseases. We propose a convenient means of blood flow volume measurement at peripheral part, such as fingertips. Principle of this measurement is based on heat transfer characteristics of peripheral part containing the blood flow. Transition response analysis of skin surface temperature has provided measurement model of the peripheral blood flow volume. We developed the blood flow measurement system based on that model and evaluated it by using artificial finger under various temperature conditions of ambience and internal fluid. The evaluation results indicated that proposed method could estimate the volume of the fluid regardless of temperature condition of them. Finally we applied our system to real finger testing and have obtained results correlated well with laser Doppler blood flow meter values.

  15. Method and apparatus for coal analysis and flow measurement

    SciTech Connect

    Rollwitz, W.L.; King, J.D.

    1985-07-23

    A flow meter apparatus and method for measuring the flow, composition and heat content of coal is set forth. In the preferred and illustrated embodiment, the free or unpaired electron population of flowing coal is measured by electron magnetic resonance (EMR); the hydrogen nucleii population is measured by nuclear magnetic resonance (NMR). By calibration utilizing a standard specimen for a given type of coal, a profile for various types of coal can be obtained wherein measurement data is converted into an indication of the heat content typically measured in BTU per pound. This enables provision of a volumetric flow meter, a flow meter indicating flow in calorie content. This device enables integration to provide total heat content flow. Other variables describing the coal can be obtained.

  16. Evaluation of a watershed model for estimating daily flow using limited flow measurements

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Soil and Water Assessment Tool (SWAT) model was evaluated for estimation of continuous daily flow based on limited flow measurements in the Upper Oyster Creek (UOC) watershed. SWAT was calibrated against limited measured flow data and then validated. The Nash-Sutcliffe model Efficiency (NSE) and...

  17. System for measuring multiphase flow using multiple pressure differentials

    DOEpatents

    Fincke, James R.

    2003-01-01

    An improved method and system for measuring a multi-phase flow in a pressure flow meter. An extended throat venturi is used and pressure of the multi-phase flow is measured at three or more positions in the venturi, which define two or more pressure differentials in the flow conduit. The differential pressures are then used to calculate the mass flow of the gas phase, the total mass flow, and the liquid phase. The system for determining the mass flow of the high void fraction fluid flow and the gas flow includes taking into account a pressure drop experienced by the gas phase due to work performed by the gas phase in accelerating the liquid phase.

  18. Measurement of cold neutron spectra using a model cryogenic moderator of the IBR-2M reactor

    NASA Astrophysics Data System (ADS)

    Kulikov, S. A.; Kalinin, I. V.; Morozov, V. M.; Novikov, A. G.; Puchkov, A. V.; Chernikov, A. N.; Shabalin, E. P.

    2010-01-01

    The method and results of an experiment to determine the cold neutron spectrum from solid mesitylene at moderator temperatures of 10-50 K are presented. This study was performed at the DIN-2PI spectrometer of the IBR-2 reactor. The objective of the study was to verify the system of constants used in the Monte Carlo simulation of cryogenic neutron moderators of the IBR-2M reactor and to obtain the cold neutron yield as a function of the moderator temperature. Satisfactory agreement between the experimental and calculated neutron spectra at a mesitylene temperature of 20 K has been obtained; the ratio of cold neutron intensities at 10 and 50 K is ˜1.8.

  19. Gravimetric method for the dynamic measurement of urine flow.

    PubMed

    Steele, J E; Skarlatos, S; Brand, P H; Metting, P J; Britton, S L

    1993-10-01

    The rate of urine formation is a primary index of renal function, but no techniques are currently available to accurately measure low rates of urine flow on a continuous basis, such as are normally found in rats. We developed a gravimetric method for the dynamic measurement of urine flow in anesthetized rats. Catheters were inserted directly into the ureters close to the renal pelves, and a siphon was created to collect all of the urine formed as rapidly as it was produced. Urine flow was determined by measuring the weight of the urine using a direct-reading analytical balance interfaced to a computer. Basal urine flow was measured at 2-sec intervals for 30 to 60 min. The dynamic response of urine flow to a rapid decrease in arterial pressure produced by a bolus intravenous injection of acetylcholine (0.5 micrograms) was also measured. Intrinsic drift, evaporative losses, and the responsiveness of the system to several fixed pump flows in the low physiologic range were evaluated in vitro. The gravimetric method described was able to continuously measure basal urine flows that averaged 37.3 +/- 12.4 microliters/min. Error due to drift and evaporation was negligible, totaling less than 1% of the measured urine flow. Acetylcholine-induced declines in arterial pressure were followed within 8 sec by a decline in urine flow. These data demonstrate that this new gravimetric method provides a simple, inexpensive, dynamic measurement of urine flow in the microliter/min range. PMID:8372099

  20. ASRDI oxygen technology survey. Volume 6: Flow measurement instrumentation

    NASA Technical Reports Server (NTRS)

    Mann, D. B.

    1974-01-01

    A summary is provided of information available on liquid and gaseous oxygen flowmetering including an evaluation of commercial meters. The instrument types, physical principles of measurement, and performance characteristics are described. Problems concerning flow measurements of less than plus or minus two percent uncertainty are reviewed. Recommendations concerning work on flow reference systems, the use of surrogate fluids, and standard tests for oxygen flow measurements are also presented.

  1. C-III flow measurements with a coherence imaging spectrometer

    SciTech Connect

    Weber, T. R.; Allen, S. L.; Howard, J.

    2012-10-15

    This work describes a coherence imaging spectrometer capable of making spatially resolved CIII flow measurements in the DIII-D lower divertor. The spectrometer exploits a periscope view of the plasma to produce line-of-sight averaged velocity measurements of CIII. From these chord averaged flow measurements, a 2D poloidal cross section of the CIII flow is tomographically reconstructed. Details of the diagnostic setup, acquired data, and data analysis will be presented, along with prospects for future applications.

  2. Comparison of precipitable water vapor derived from radiosonde, GPS, and Moderate-Resolution Imaging Spectroradiometer measurements

    NASA Astrophysics Data System (ADS)

    Li, Zhenhong; Muller, Jan-Peter; Cross, Paul

    2003-10-01

    Atmospheric water vapor is highly variable in both space and time across the Earth, and knowledge of the distribution of water vapor is essential in understanding weather and global climate. In addition, knowledge of the amount of atmospheric water vapor is required for high-precision interferometric synthetic aperture radar (InSAR) applications due to its significant impact on microwave signals, which is the principal motivation for this study. In order to assess the performance of different instruments, i.e., radiosondes (RS), Global Positioning System (GPS), and the Moderate-Resolution Imaging Spectroradiometer (MODIS) and for measuring precipitable water vapor (PWV), coincident observations collected at the Atmospheric Radiation Measurement Southern Great Plains site and at the Herstmonceux site over a 8-11 month period are used for time series intercomparisons. In this study, the Terra MODIS near-infrared water vapor products (Collection 3) were examined. In addition, a first spatial comparison of MODIS PWV and GPS PWV was performed using data covering all of Germany and kindly supplied by the GeoForschungsZentrum Potsdam. Time series comparisons of PWV between radiosondes and GPS show that the scale factors of PWV from radiosondes and GPS agreed to 4% with correlation coefficients higher than 0.98 and standard deviations about 1 mm. A significant day-night difference was found for Vaisala RS90 radiosondes in comparison with GPS PWV, with nighttime launches having a scale factor 4% larger, but agreeing overall better. It is also shown that GPS PWV and RS PWV agreed better with each other than with MODIS PWV, and the differences of MODIS PWV relative to GPS or RS were larger than those between GPS PWV and RS PWV. MODIS PWV appeared to overestimate PWV against RS, with scale factors from 1.14 to 1.20 and standard deviations from 1.6 to 2.2 mm. MODIS PWV appeared to overestimate PWV against GPS, with scale factors from 1.07 to 1.14 and standard deviations varying

  3. Continuous flow measurements using fixed ultrasonic meters

    USGS Publications Warehouse

    Oltmann, Rick

    1993-01-01

    USGS has or soon will be installing four continuous flow-monitoring stations in the delta that will use ultrasonic velocity meters (DVM). Funding for the stations has been provided by USGS, DWR, USBR, and Contra Costa Water District.

  4. Efficiencies of intracoronary sodium nitroprusside on fractional flow reserve measurement

    PubMed Central

    Li, Shaosheng; Deng, Jie; Wang, Xiaozeng; Zhao, Xin; Han, Yaling

    2015-01-01

    Background: Fractional flow reserve (FFR) has certain advantages of assessing functional severity of coronary stenosis. Adenosine(AD) is the most widely used agents in FFR measurement but has the disadvantages of higher rate of complications. Sodium Nitroprusside (SNP) represents a valuable alternative. Methods and results: In 75 patients with 86 moderate coronary stenosis, FFR values, heart rate and blood pressure were measured at baseline, after 0.6 μg boluses of intracoronary (IC) SNP, and after 140 μg/kg /min of continuous intravenous (IV) AD. FFR values decreased significantly after administering IV AD and IC SNP compared with the baseline Pd/Pa values (P < 0.001). Mean FFR induced by IV AD was not significantly different from that by IC SNP (t = 0.577, P = 0.566). The mean kappa value in the evaluation of two methods was 0.973 for FFR. There was a significant correlation between the FFR values of IV AD and IC SNP (R = 0.911, P < 0.001). Significant decreases in the blood pressures were found after agents were given compared to the baseline. No significant difference was found between AD and SNP. In addition, immediate complications occurred in 60.5% patients of IV AD in contrast to no adverse events after IC SNP. Conclusion: SNP is a safe and effective agent and easy to use for the FFR measurement. Maximal hyperemia by IC SNP is equivalent to that by IV AD. IC SNP could be considered a potential alternative in patients with contraindications to AD administration. PMID:25932219

  5. Flow Measurement. Training Module 3.315.2.77.

    ERIC Educational Resources Information Center

    Kirkwood Community Coll., Cedar Rapids, IA.

    This document is an instructional module package prepared in objective form for use by an instructor familiar with the principles of liquid flow and the methods of measuring open channel and fuel pipe flow rates. Included are objectives, instructor guides, student handouts, and transparency masters. The module addresses the basic flow formula, and…

  6. Field methods for measuring concentrated flow erosion

    NASA Astrophysics Data System (ADS)

    Castillo, C.; Pérez, R.; James, M. R.; Quinton, J. N.; Taguas, E. V.; Gómez, J. A.

    2012-04-01

    techniques (3D) for measuring erosion from concentrated flow (pole, laser profilemeter, photo-reconstruction and terrestrial LiDAR) The comparison between two- and three-dimensional methods has showed the superiority of the 3D techniques for obtaining accurate cross sectional data. The results from commonly-used 2D methods can be subject to systematic errors in areal cross section that exceed magnitudes of 10 % on average. In particular, the pole simplified method has showed a clear tendency to understimate areas. Laser profilemeter results show that further research on calibrating optical devices for a variety of soil conditions must be carried out to improve its performance. For volume estimations, photo-reconstruction results provided an excellent approximation to terrestrial laser data and demonstrate that this new remote sensing technique has a promising application field in soil erosion studies. 2D approaches involved important errors even over short measurement distances. However, as well as accuracy, the cost and time requirements of a technique must be considered.

  7. Cerebral aneurysms treated with flow-diverting stents: Computational models using intravascular blood flow measurements

    PubMed Central

    Levitt, Michael R; McGah, Patrick M; Aliseda, Alberto; Mourad, Pierre D; Nerva, John D; Vaidya, Sandeep S; Morton, Ryan P; Ghodke, Basavaraj V; Kim, Louis J

    2013-01-01

    Background and Purpose Computational fluid dynamics modeling is useful in the study of the hemodynamic environment of cerebral aneurysms, but patient-specific measurements of boundary conditions, such as blood flow velocity and pressure, have not been previously applied to the study of flow-diverting stents. We integrated patient-specific intravascular blood flow velocity and pressure measurements into computational models of aneurysms before and after treatment with flow-diverting stents to determine stent effects on aneurysm hemodynamics. Methods Blood flow velocity and pressure were measured in peri-aneurysmal locations using an intravascular dual-sensor pressure and Doppler velocity guidewire before and after flow-diverting stent treatment of four unruptured cerebral aneurysms. These measurements defined inflow and outflow boundary conditions for computational models. Intra-aneurysmal flow rates, wall shear stress and wall shear stress gradient were calculated. Results Measurements of inflow velocity and outflow pressure were successful in all four patients. Computational models incorporating these measurements demonstrated significant reductions in intra-aneurysmal wall shear stress and wall shear stress gradient, and a trend in reduced intra-aneurysmal blood flow. Conclusions Integration of intravascular dual-sensor guidewire measurements of blood flow velocity and blood pressure provided patient-specific computational models of cerebral aneurysms. Aneurysm treatment with flow-diverting stents reduces blood flow and hemodynamic shear stress in the aneurysm dome. PMID:23868162

  8. Two-phase flow measurement based on oblique laser scattering

    NASA Astrophysics Data System (ADS)

    Vendruscolo, Tiago P.; Fischer, Robert; Martelli, Cícero; Rodrigues, Rômulo L. P.; Morales, Rigoberto E. M.; da Silva, Marco J.

    2015-07-01

    Multiphase flow measurements play a crucial role in monitoring productions processes in many industries. To guarantee the safety of processes involving multiphase flows, it is important to detect changes in the flow conditions before they can cause damage, often in fractions of seconds. Here we demonstrate how the scattering pattern of a laser beam passing a two-phase flow under an oblique angle to the flow direction can be used to detect derivations from the desired flow conditions in microseconds. Applying machine-learning techniques to signals obtained from three photo-detectors we achieve a compact, versatile, low-cost sensor design for safety applications.

  9. Gas/oil/water flow measurement by electrical capacitance tomography

    NASA Astrophysics Data System (ADS)

    Li, Yi; Yang, Wuqiang; Xie, Cheng-gang; Huang, Songming; Wu, Zhipeng; Tsamakis, Dimitrios; Lenn, Chris

    2013-07-01

    In the oil industry, it is important to measure gas/oil/water flows produced from oil wells. To determine oil production, it is necessary to measure the water-in-liquid ratio (WLR), liquid fraction and some other parameters, which are related to multiphase flow rates. A research team from the University of Manchester and Schlumberger Gould Research have developed an experimental apparatus for gas/oil/water flow measurement based on a flow-conditioning device and electrical capacitance tomography (ECT) and microwave sensors. This paper presents the ECT part of the developed apparatus, including the re-engineering of an ECT sensor and a model-based image reconstruction algorithm, which is used to derive the WLR and the thickness of the liquid layer in oil-continuous annular flows formed by the flow-conditioning device. The ECT sensor was tested both at Schlumberger and on TUV-NEL's Multiphase Flow Facility. The experimental results are promising.

  10. Measurement and control systems for an imaging electromagnetic flow metre.

    PubMed

    Zhao, Y Y; Lucas, G; Leeungculsatien, T

    2014-03-01

    Electromagnetic flow metres based on the principles of Faraday's laws of induction have been used successfully in many industries. The conventional electromagnetic flow metre can measure the mean liquid velocity in axisymmetric single phase flows. However, in order to achieve velocity profile measurements in single phase flows with non-uniform velocity profiles, a novel imaging electromagnetic flow metre (IEF) has been developed which is described in this paper. The novel electromagnetic flow metre which is based on the 'weight value' theory to reconstruct velocity profiles is interfaced with a 'Microrobotics VM1' microcontroller as a stand-alone unit. The work undertaken in the paper demonstrates that an imaging electromagnetic flow metre for liquid velocity profile measurement is an instrument that is highly suited for control via a microcontroller. PMID:24139307

  11. Wind-flow measurement over the Subaru Telescope.

    PubMed

    Horikawa, Hirofumi; Baba, Naoshi; Ohtsubo, Masashi; Norimoto, Yuji; Nishimura, Tetsuo; Miura, Noriaki

    2004-05-20

    Wind flows over the 8.2-m Subaru Telescope at Mauna Kea in Hawaii were analyzed with a correlation method. Three or four wind flows were detected from our measurements. Spatial and temporal resolution of the wind-flow analysis across the 8.2 m pupil were investigated experimentally. A three-dimensional spatiotemporal-frequency analysis was also applied to the wind-flow data. PMID:15176198

  12. Large, Moderate or Small? The Challenge of Measuring Mass Eruption Rates in Volcanic Eruptions

    NASA Astrophysics Data System (ADS)

    Gudmundsson, M. T.; Dürig, T.; Hognadottir, T.; Hoskuldsson, A.; Bjornsson, H.; Barsotti, S.; Petersen, G. N.; Thordarson, T.; Pedersen, G. B.; Riishuus, M. S.

    2015-12-01

    The potential impact of a volcanic eruption is highly dependent on its eruption rate. In explosive eruptions ash may pose an aviation hazard that can extend several thousand kilometers away from the volcano. Models of ash dispersion depend on estimates of the volcanic source, but such estimates are prone to high error margins. Recent explosive eruptions, including the 2010 eruption of Eyjafjallajökull in Iceland, have provided a wealth of data that can help in narrowing these error margins. Within the EU-funded FUTUREVOLC project, a multi-parameter system is currently under development, based on an array of ground and satellite-based sensors and models to estimate mass eruption rates in explosive eruptions in near-real time. Effusive eruptions are usually considered less of a hazard as lava flows travel slower than eruption clouds and affect smaller areas. However, major effusive eruptions can release large amounts of SO2 into the atmosphere, causing regional pollution. In very large effusive eruptions, hemispheric cooling and continent-scale pollution can occur, as happened in the Laki eruption in 1783 AD. The Bárdarbunga-Holuhraun eruption in 2014-15 was the largest effusive event in Iceland since Laki and at times caused high concentrations of SO2. As a result civil protection authorities had to issue warnings to the public. Harmful gas concentrations repeatedly persisted for many hours at a time in towns and villages at distances out to 100-150 km from the vents. As gas fluxes scale with lava fluxes, monitoring of eruption rates is therefore of major importance to constrain not only lava but also volcanic gas emissions. This requires repeated measurements of lava area and thickness. However, most mapping methods are problematic once lava flows become very large. Satellite data on thermal emissions from eruptions have been used with success to estimate eruption rate. SAR satellite data holds potential in delivering lava volume and eruption rate estimates

  13. Drop-box Weir for Measuring Flow Rates Under Extreme Flow Conditions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sediment and large rocks often are transported in runoff during extreme events. The sediment can deposit in a runoff-measuring structure and give erroneous readings. The drop-box weir (DBW) is one of only a few flow-measuring devices capable of measuring sediment-laden flows. Recent studies have ...

  14. Blood flow measurements within optic nerve head during on-pump cardiovascular operations. A window to the brain?

    PubMed

    Nenekidis, Ioannis; Geiser, Martial; Riva, Charles; Pournaras, Constantin; Tsironi, Evangelia; Vretzakis, Georgios; Mitilis, Vasilios; Tsilimingas, Nikolaos

    2011-05-01

    This observational study is conducted to demonstrate optic nerve head (ONH) blood flow alterations during extracorporeal circulation (ECC) in routine on-pump cardiovascular operations in order to evaluate the perfusion status of important autoregulatory tissue vascular beds during moderate hypothermia. Twenty-one patients free from eye disease were prospectively enrolled in our database. Perioperative ONH blood flow measurements were performed using a hand-held portable ocular laser Doppler flowmeter just after administration of general anesthesia and during cardiopulmonary bypass (CPB) upon the lowest temperature point of moderate hypothermia. Important operative flow variables were correlated to optic nerve blood flow during surgical phases. Statistical analysis showed significant reduction of 32.1 ± 14.5% of mean ONH blood flow in phase 2 (P < 0.0001) compared to the reference flow values of phase 1. A negative univariate association between ECC time and ONH blood flow in phase 2 (P = 0.031) is noted. This angiokinetic approach can detect changes of flow within autoregulatory vascular tissue beds like ONH, thus creating a 'window' on cerebral microvasculature. ONH blood flow is reduced during CPB. Our data suggest that it is of paramount importance to avoid extracorporeal prolongation even in moderate hypothermic cardiovascular operations. PMID:21297131

  15. Development of an aerodynamic measurement system for hypersonic rarefied flows.

    PubMed

    Ozawa, T; Fujita, K; Suzuki, T

    2015-01-01

    A hypersonic rarefied wind tunnel (HRWT) has lately been developed at Japan Aerospace Exploration Agency in order to improve the prediction of rarefied aerodynamics. Flow characteristics of hypersonic rarefied flows have been investigated experimentally and numerically. By conducting dynamic pressure measurements with pendulous models and pitot pressure measurements, we have probed flow characteristics in the test section. We have also improved understandings of hypersonic rarefied flows by integrating a numerical approach with the HRWT measurement. The development of the integration scheme between HRWT and numerical approach enables us to estimate the hypersonic rarefied flow characteristics as well as the direct measurement of rarefied aerodynamics. Consequently, this wind tunnel is capable of generating 25 mm-core flows with the free stream Mach number greater than 10 and Knudsen number greater than 0.1. PMID:25638120

  16. Application of gamma densitometer for measurement of void fraction in liquid hydrogen moderator of HANARO cold neutron source

    NASA Astrophysics Data System (ADS)

    Kim, Myong-Seop; Choi, Jungwoon; Sun, Gwang-Min; Lee, Kye-Hong

    2009-06-01

    The void fraction in the liquid hydrogen used for the moderator of the HANARO cold neutron source (CNS) was measured by using a gamma densitometer technique. A mock-up of the HANARO CNS facility with an electric heating system as the heat source instead of radiations was constructed. The photon transmissions through the hydrogen moderator were simulated to search for an optimum experimental condition. From the simulation, it was confirmed that Am-241 was suitable for the measurement of the void fraction in the liquid hydrogen medium. A gamma densitometer using the Am-241 gamma-ray source was designed and installed at the mock-up of the CNS. The attenuation of 59.5 keV gamma-rays from the Am-241 through the hydrogen medium was measured by using an HPGe detector. The void fraction was determined using the amount of the gamma-ray attenuation. The void fractions in the hydrogen moderator were measured for stable thermo-siphon loops with several electric heat loads applied to the moderator cell of the CNS mock-up. The longitudinal distribution of the void fraction inside the moderator cell was also determined. The void fraction measured at a heat load of 720 W had values of 8-41% depending on the height from the bottom of the moderator cell. The overall void fraction was obtained by volume-weighted averaging of its longitudinal distribution. The void fraction at the nuclear heating power expected at the normal operation condition of the HANARO CNS facility was determined to be about 20%. The large uncertainty was expected in the void fraction determination by a gamma densitometer for the liquid hydrogen medium with the void fraction less than 10%. When the void fraction of the liquid hydrogen was near 20%, the uncertainty in the void fraction determination by using a gamma densitometer became relatively small, and it was regarded as an acceptable level. The measurements for the void fraction will be very useful for the design and operation of the HANARO CNS.

  17. Fiber optic sensor for flow and viscosity measurement

    NASA Astrophysics Data System (ADS)

    Wang, Wei-Chih; Leang, Jonathan

    2016-04-01

    A sensitive fluid viscosity and flow measurement device using optical intensity based sensing is presented. The sensing principle makes use of the damping characteristic of a vibrating optical fiber probe with approximate hinge-free end configuration. The viscosity and mass flow are determined by measuring the vibration of a sinusoidally excited tapered optical fiber under different flow conditions. By measuring the frequency response of the fiber probe, viscosity and mass flow can be deduced from the damping coefficient of the response. The concepts and experimental data presented demonstrate and refine the sensing process of the proposed system.

  18. Laser anemometer measurements in a transonic axial flow compressor rotor

    NASA Technical Reports Server (NTRS)

    Strazisar, A. J.; Powell, J. A.

    1979-01-01

    A laser anemometer system employing an efficient data acquisition technique was used to make measurements upstream, within, and downstream of the compressor rotor. A fluorescent dye technique allowed measurements within endwall boundary layers. Adjustable laser beam orientation minimized shadowed regions and enabled radial velocity measurements outside of the blade row. The flow phenomena investigated include flow variations from passage to passage, the rotor shock system, three-dimensional flows in the blade wake, and the development of the outer endwall boundary layer. Laser anemometer measurements are compared to a numerical solution of the streamfunction equations and to measurements made with conventional instrumentation.

  19. Ambient flow studies and particulate collection measurements: A laminar flow, reduced entrainment electrostatic precipitator

    SciTech Connect

    Greiner, G.P.; Furlong, D.A.; Bahner, M.A.

    1989-05-01

    This report describes ambient temperature testing of an electrostatic precipitator having a portion of the main precipitator flow drawn through porous (fabric) plates. The effects of flow through the plates (side flow) on precipitator turbulence and particulate removal efficiency are investigated. Ambient temperature particulate removal efficiency measurements are conducted on both indoor air dust, and on injected coal fly ash. 24 figs., 10 tabs.

  20. 40 CFR 90.417 - Fuel flow measurement specifications.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... specifications of 40 CFR part 1065, subpart C, instead of those in this paragraph (b). ... measurement instrument must have a minimum accuracy of one percent of full-scale flow rate for each... ±five percent of full-scale flow rate for the measurement range used. The controlling parameters are...

  1. Measurements of small radius ratio turbulent Taylor-Couette flow

    NASA Astrophysics Data System (ADS)

    van der Veen, Roeland; Huisman, Sander; Merbold, Sebastian; Sun, Chao; Harlander, Uwe; Egbers, Christoph; Lohse, Detlef

    2014-11-01

    In Taylor-Couette flows, the radius ratio (η =ri /ro) is one of the key parameters of the system. For small η, the asymmetry of the inner and outer boundary layer becomes more important, affecting the general flow structure and boundary layer characteristics. Using high-resolution particle image velocimetry we measure flow profiles, local transport, and statistical properties of the flow for a radius ratio of 0.5 and a Reynolds number of up to 4 .104 . By measuring flow profiles at varying heights, roll structures are characterized for two different rotation ratios of the inner and outer cylinder. In addition, we systematically vary the rotation ratio and the Reynolds number. These results exemplify how curvature affects flow in strongly turbulent Taylor-Couette Flow.

  2. Capacitance probe for fluid flow and volume measurements

    NASA Technical Reports Server (NTRS)

    Arndt, G. Dickey (Inventor); Nguyen, Thanh X. (Inventor); Carl, James R. (Inventor)

    1995-01-01

    Method and apparatus for making measurements on fluids are disclosed, including the use of a capacitive probe for measuring the flow volume of a material within a flow stream. The capacitance probe has at least two elongate electrodes and, in a specific embodiment of the invention, has three parallel elongate electrodes with the center electrode being an extension of the center conductor of a co-axial cable. A conductance probe is also provided to provide more accurate flow volume data in response to conductivity of the material within the flow stream. A preferred embodiment of the present invention provides for a gas flow stream through a microgravity environment that allows for monitoring a flow volume of a fluid sample, such as a urine sample, that is entrained within the gas flow stream.

  3. Capacitance Probe for Fluid Flow and Volume Measurements

    NASA Technical Reports Server (NTRS)

    Arndt, G. Dickey (Inventor); Nguyen, Thanh X. (Inventor); Carl, James R. (Inventor)

    1997-01-01

    Method and apparatus for making measurements on fluids are disclosed, including the use of a capacitive probe for measuring the flow volume of a material within a flow stream. The capacitance probe has at least two elongate electrodes and, in a specific embodiment of the invention, has three parallel elongate electrodes with the center electrode being an extension of the center conductor of a co-axial cable. A conductance probe is also provided to provide more accurate flow volume data in response to conductivity of the material within the flow stream. A preferred embodiment of the present invention provides for a gas flow stream through a micro-gravity environment that allows for monitoring a flow volume of a fluid sample, such as a urine sample, that is entrained within the gas flow stream.

  4. Flow measurement in mechanical ventilation: a review.

    PubMed

    Schena, Emiliano; Massaroni, Carlo; Saccomandi, Paola; Cecchini, Stefano

    2015-03-01

    Accurate monitoring of flow rate and volume exchanges is essential to minimize ventilator-induced lung injury. Mechanical ventilators employ flowmeters to estimate the amount of gases delivered to patients and use the flow signal as a feedback to adjust the desired amount of gas to be delivered. Since flowmeters play a crucial role in this field, they are required to fulfill strict criteria in terms of dynamic and static characteristics. Therefore, mechanical ventilators are equipped with only the following kinds of flowmeters: linear pneumotachographs, fixed and variable orifice meters, hot wire anemometers, and ultrasonic flowmeters. This paper provides an overview of these sensors. Their working principles are described together with their relevant advantages and disadvantages. Furthermore, the most promising emerging approaches for flowmeters design (i.e., fiber optic technology and three dimensional micro-fabrication) are briefly reviewed showing their potential for this application. PMID:25659299

  5. The Moderated Relationship of Appearance Valence on Appearance Self Consciousness: Development and Testing of New Measures of Appearance Schema Components

    PubMed Central

    Moss, Timothy P.; Rosser, Benjamin A.

    2012-01-01

    This paper describes the creation and psychometric properties of two independent measures of aspects of appearance schematicity – appearance salience and valence, assessed by the CARSAL and CARVAL, and their relation to appearance self-consciousness. Five hundred and ninety two participants provided data in a web based task. The results demonstrate the sound psychometric properties of both scales. This was demonstrated by good item total characteristics, good internal reliability of each scale, and the independence of the two scales shown through principal components analysis. Furthermore, the scales show independent and moderated relationships with valid measures of appearance related psychosocial distress. Negatively valenced appearance information was associated with increased appearance self-consciousness. More crucially, the impact of negative valence on appearance self-consciousness was exacerbated by the moderating effect increased salience of appearance. PMID:23226326

  6. Real-Time Measurement of Vehicle Exhaust Gas Flow

    SciTech Connect

    Hardy, J.E.; Hylton, J.O.; Joy, R.D.; McKnight, T.E.

    1999-06-28

    A flow measurement system was developed to measure, in real-time, the exhaust gas flow from vehicies. This new system was based on the vortex shedding principle using ultrasonic detectors for sensing the shed vortices. The flow meter was designed to measure flow over a range of 1 to 366 Ips with an inaccuracy of ~1o/0 of reading. Additionally, the meter was engineered to cause minimal pressure drop (less than 125mm of water), to function in a high temperature environment (up to 650oC) with thermal transients of 15 oC/s, and to have a response time of 0.1 seconds for a 10% to 90!40 step change. The flow meter was also configured to measure hi-directional flow. Several flow meter prototypes were fabricated, tested, and calibrated in air, simulated exhaust gas, and actual exhaust gas. Testing included gas temperatures to 600oC, step response experiments, and flow rates from O to 360 lps in air and exhaust gas. Two prototypes have been tested extensively at NIST and two additional meters have been installed in exhaust gas flow lines for over one year. This new flow meter design has shown to be accurate, durabIe, fast responding, and to have a wide rangeabi~ity.

  7. MRI Based Diagnostics for Temperature Measurements in Turbulent Flows

    NASA Astrophysics Data System (ADS)

    Burton, Lauren Sascha; Elkins, Christopher J.; Eaton, John K.

    2014-11-01

    Accurate modeling of the thermal diffusion in the complex turbulent flows related to cooling high temperature gas turbine blades is critical to optimize the performance and predict the lifetime of the blades. Magnetic Resonance Imaging (MRI) techniques for temperature measurement in simple but related flows are being developed in an effort to obtain full field thermal measurements to better understand diffusion processes and support the development of more accurate computational models in these flows. Magnetic Resonance Thermometry (MRT) utilizes the temperature dependence of the hydrogen proton resonant frequency (PRF) in water. MRT is now routinely used to measure tissue temperatures during medical procedures, and a few previous studies have made velocity and temperature measurements in turbulent pipe flows. In this study, MRT is applied to the flow of a heated single hole film cooling jet (Reynolds number 3000) inclined at 30 degrees injected into a cold developing turbulent channel flow (Reynolds number 25,000 based on bulk velocity and channel height.) The jet fluid temperature is 30 degrees Celsius above the temperature in the channel. The temperature measurements compare well to previously published results for measured passive scalar concentration in the same flow although the temperature measurements show higher uncertainties of 5--10 % of the temperature difference. Techniques for reducing this uncertainty will be presented as well as procedures for applying MRT to quantify the turbulent heat transfer coefficient in turbulent internal flows.

  8. Bulk temperature measurement in thermally striped pipe flows

    SciTech Connect

    Lemure, N.; Olvera, J.R.; Ruggles, A.E.

    1995-12-01

    The hot leg flows in some Pressurized Water Reactor (PWR) designs have a temperature distribution across the pipe cross-section. This condition is often referred to as a thermally striped flow. Here, the bulk temperature measurement of pipe flows with thermal striping is explored. An experiment is conducted to examine the feasibility of using temperature measurements on the external surface of the pipe to estimate the bulk temperature of the flow. Simple mixing models are used to characterize the development of the temperature profile in the flow. Simple averaging techniques and Backward Propagating Neural Net are used to predict bulk temperature from the external temperature measurements. Accurate bulk temperatures can be predicted. However, some temperature distributions in the flow effectively mask the bulk temperature from the wall and cause significant error in the bulk temperature predicted using this technique.

  9. Time-resolved fluorescence decay measurements for flowing particles

    DOEpatents

    Deka, C.; Steinkamp, J.A.

    1999-06-01

    Time-resolved fluorescence decay measurements are disclosed for flowing particles. An apparatus and method for the measurement and analysis of fluorescence for individual cells and particles in flow are described, wherein the rapid measurement capabilities of flow cytometry and the robust measurement and analysis procedures of time-domain fluorescence lifetime spectroscopy are combined. A pulse-modulated CW laser is employed for excitation of the particles. The characteristics and the repetition rate of the excitation pulses can be readily adjusted to accommodate for fluorescence decays having a wide range of lifetimes. 12 figs.

  10. Time-resolved fluorescence decay measurements for flowing particles

    DOEpatents

    Deka, Chiranjit; Steinkamp, John A.

    1999-01-01

    Time-resolved fluorescence decay measurements for flowing particles. An apparatus and method for the measurement and analysis of fluorescence for individual cells and particles in flow are described, wherein the rapid measurement capabilities of flow cytometry and the robust measurement and analysis procedures of time-domain fluorescence lifetime spectroscopy are combined. A pulse-modulated cw laser is employed for excitation of the particles. The characteristics and the repetition rate of the excitation pulses can be readily adjusted to accommodate for fluorescence decays having a wide range of lifetimes.

  11. Measurement of two-component flow using ultrasonic flowmeters

    NASA Astrophysics Data System (ADS)

    Whitehouse, J. C.; Eghbali, D. A.; Flitton, V. E.; Anderson, D. G.

    Calibration of transit-time and Doppler ultrasonic flowmeters under two-component flow conditions has been conducted on 400 mm (16-in.) pipe. Testing covered total flows of 0.19 to 1.89 m(exp 3)/s (3000 to 30,000 gpm) and void fractions up to 40 percent. Both flowmeter types accurately measured total volumetric flow over a portion of their ranges. Pipe average void fraction, based on a three-beam gamma densitometer, was used to determine water component flow under stratified flow conditions, with similar results.

  12. New technology directly measures mass flow of gas

    SciTech Connect

    Hahn, D.T.

    1995-12-31

    According to recent industry surveys and solicitations by organizations such as the Gas Research Institute and Small Business Innovation Research, a need exists for a gas flowmeter with {plus_minus}0.5% or better accuracy, that does not need to be calibrated for specific gas properties, and requires no periodic maintenance. Over the past 18 years, Coriolis mass flowmeters have provided these features for liquid flow applications, and have won a significant share of the liquid flow measurement market. Coriolis meters continue to be the fastest growing technology in the world market for flow measurement. Coriolis mass flowmeters have not, however, had much success in penetrating the gas flow measurement market due to some limitations involved with measuring the low density fluids associated with low pressure gas flow measurement. A new type of Coriolis mass flowmeter has been developed which utilizes a unique new method of creating and measuring the requisite Coriolis forces. This new technology; radial mode Coriolis mass flow measurement, has several inherent features that make it perfectly suited to measuring the mass flow of gas.

  13. Visualization and velocity measurement of unsteady flow in a gas generator using cold-flow technique

    NASA Astrophysics Data System (ADS)

    Kuppa, Subrahmanyam

    1990-08-01

    Modeling of internal flow fields with hot, compressible fluids and sometimes combustion using cold flow techniques is discussed. The flow in a gas generator was modeled using cold air. The experimental set up was designed and fabricated to simulate the unsteady flow with different configurations of inlet tubes. Tests were run for flow visualization and measurement of axial velocity at different frequencies ranging from 5 to 12 Hz. Flow visualization showed that the incoming flow was a complex jet flow confined to a cylindrical enclosure, while the outgoing flow resembled the venting of a pressurized vessel. The pictures show a complex flow pattern due to the angling of the jet towards the wall for the bent tube configurations and straightened flows with straight tube and other configurations with straighteners. Velocity measurements were made at an inlet Re of 8.1 x 10(exp 4) based on maximum velocity and inlet diameter. Phase averaged mean velocities were observed to be well defined during charging and diminished during venting inside the cylinder. For the straight tube inlet comparison with a steady flow measurement of sudden expansion flow showed a qualitative similarity of the mean axial velocity distribution and centerline velocity decay during the charging phases. For the bent tube inlet case the contour plots showed the flow tendency towards the wall. Two cells were seen in the contours for the 8 and 12 Hz cases. The deviation of the point of occurrence of maximum velocity in a radial profile was found to be about 6.5 degrees. Entrance velocity profiles showed symmetry for the straight tube inlet but were skewed for the bent tube inlet. Contour plots of the phase averaged axial turbulence intensity for bent tube cases showed higher values in the core and near the wall in the region of impingement. Axial turbulence intensity measured for the straight tube case showed features as observed in an axisymmetric sudden expansion flow.

  14. Ultrasound Doppler Velocimetry Measurements in Turbulent Liquid Metal Channel Flow

    NASA Astrophysics Data System (ADS)

    Rivero, Michel; Jian, Dandan; Karcher, Christian; Cuevas, Sergio

    2010-11-01

    Control of molten metal flow using magnetic fields is important in industrial applications. The Electromagnetic Flow Control Channel (EFCO) is an experimental test facility, located at Ilmenau University of Technology, for the development of such kind of control systems. The working fluid is the low-melting liquid metal alloy GaInSn in eutectic composition. In this channel, flow control is realized by combining and coupling the non-contact flow driving technology of electromagnetic pumps based on rotating permanent magnets and the non-contact flow rate measurement technology termed Lorentz Force Velocimetry (LFV). The flow rate is adjusted by controlling the rotation rate of the permanent magnet system. Physically, LFV is based on measuring the force acting on a magnet system. This force is induced by the melt flow passing through the static magnetic field generated by the system and is proportional to the flow. To calibrate such flow meters, we apply UDV technique to measure and analyse both turbulent hydrodynamic and MHD flow profiles in EFCO at various Reynolds numbers.

  15. Dual-plane ultrasound flow measurements in liquid metals

    NASA Astrophysics Data System (ADS)

    Büttner, Lars; Nauber, Richard; Burger, Markus; Räbiger, Dirk; Franke, Sven; Eckert, Sven; Czarske, Jürgen

    2013-05-01

    An ultrasound measurement system for dual-plane, two-component flow velocity measurements especially in opaque liquids is presented. Present-day techniques for measuring local flow structures in opaque liquids disclose considerable drawbacks concerning line-wise measurement of single ultrasound probes. For studying time-varying flow patterns, conventional ultrasound techniques are either limited by time-consuming mechanical traversing or by the sequential operation of single probes. The measurement system presented within this paper employs four transducer arrays with a total of 100 single elements which allows for flow mapping without mechanical traversing. A high frame rate of several 10 Hz has been achieved due to an efficient parallelization scheme using time-division multiplexing realized by a microcontroller-based electronic switching matrix. The functionality and capability of the measurement system are demonstrated on a liquid metal flow at room temperature inside a cube driven by a rotating magnetic field (RMF). For the first time, the primary and the secondary flow have been studied in detail and simultaneously using a configuration with two crossed measurement planes. The experimental data confirm predictions made by numeric simulation. After a sudden switching on of the RMF, inertial oscillations of the secondary flow were observed by means of a time-resolved measurement with a frame rate of 3.4 Hz. The experiments demonstrate that the presented measurement system is able to investigate complex and transient flow structures in opaque liquids. Due to its ability to study the temporal evolution of local flow structures, the measurement system could provide considerable progress for fluid dynamics research, in particular for applications in the food industry or liquid metal technologies.

  16. Measures of flow variability for great lakes tributaries.

    PubMed

    Richards, R P

    1989-11-01

    Design of monitoring programs for load estimation is often hampered by the lack of existing chemical data from which to determine patterns of flux variance, which determine the sampling program requirements when loads are to be calculated using flux-dependent models like the Beale Ratio Estimator. In contrast, detailed flow data are generally available for the important tributaries. For pollutants from non-point sources there is often a correlation between flow and pollutant flux. Thus, measures of flow variability might be calibrated to flux variability for well-known watersheds, after which flow variability could be used as a proxy for flux variability to estimate sampling needs for tributaries for which adequate chemical observations are lacking.Three types of measures of flow variability were explored: ratio measures, which are of the form q x/qy, where q xis the flow corresponding to the percentile x, and y=100-x; spread measures, of the form (q x-qy)/qm, where q mis the median flow; and the coefficient of variation of the logs of flows. In the latter, flows are log transformed because flow distributions are often approximately log-normal. Three ratio measures were evaluated, based on the percentiles (10,90), (20,80), and (25,75). The analogous spread measures were also evaluated; the spread measure based on percentiles (25,75) is derived from the commonly used fourth spread of non-parametric statistics. The ratio measures and the spread measures are scale independent, and thus are measures only of the shape of the distribution. The coefficient of variation is also scale independent, but in log space.Values of these measures of flow variability for 120 Great Lakes tributaries are highly intercorrelated, although the relationship is often non-linear. The coefficient of variation of the log of the flows is also well correlated with the coefficient of variation of fluxes of suspended solids, total phosphorus, and chloride, for a smaller set of rivers where the

  17. The Use of Curriculum-Based Measures in Young At-Risk Writers: Measuring Change over Time and Potential Moderators of Change

    ERIC Educational Resources Information Center

    Costa, Lara-Jeane C.; Hooper, Stephen R.; McBee, Matthew; Anderson, Kathleen L.; Yerby, Donna Carlson

    2012-01-01

    This study examined gains in written language as assessed by targeted curriculum-based measures (CBMs), and explored how these gains were affected by moderator variables of specific cognitive functions and student subgroups. The sample included 68 second grade students who were at risk for writing disabilities. Handwritten compositions were…

  18. Unseeded Scalar Velocity Measurements for Propulsion Flows

    NASA Technical Reports Server (NTRS)

    Pitz, Robert W.; Wehrmeyer, Joseph A.; Seasholtz, Richard G. (Technical Monitor)

    2000-01-01

    Unseeded molecular tagging methods based on single-photon processes that produce long tag lines (>50 mm) have been recently developed and demonstrated by the Combustion Laser Diagnostics Group (Mechanical Engineering Department) at Vanderbilt University [1,2]. In Ozone Tagging Velocimetry (OTV) a line of ozone (O3) is produced by a single photon from a pulsed narrowband argon fluoride (ArF) excimer laser operating at - 193 nm. After a known time delay, t, the position of the displaced (convected in the flow field) O3 tag line is revealed by photodissociation of O3 and subsequent fluorescence of O2, caused by a pulsed laser sheet from a krypton fluoride (KrF) excimer laser operating at - 248 nm. Intensified CCD camera images of the fluorescence are taken from the initial and final tag line locations thus providing unobtrusive means of establishing a velocity profile in the interrogated flow field. The O3 lines are "written" and subsequently "read" by the following reactions:

  19. Measuring bovine mammary gland blood flow using a transit time ultrasonic flow probe.

    PubMed

    Gorewit, R C; Aromando, M C; Bristol, D G

    1989-07-01

    Lactating cattle were used to validate a transit time ultrasonic blood flow metering system for measuring mammary gland arterial blood flow. Blood flow probes were surgically placed around the right external pudic artery. An electromagnetic flow probe was implanted in tandem with the ultrasonic probe in two cows for comparative measurements. The absolute accuracy of the implanted flow probes was assessed in vivo by mechanical means on anesthetized cows after 2 to 3 wk of implantation. The zero offset of the ultrasonic probes ranged from -12 to 8 ml/min. When the ultrasonic probe was properly implanted, the slopes of the calibration curves were linear and ranged from .92 to .95, tracking absolute flow to within 8%. The transit time instrument's performance was examined under a variety of physiological conditions. These included milking and hormone injections. The transit time ultrasonic flow meter accurately measured physiological changes in mammary arterial blood flow in chronically prepared conscious cattle. Blood flow increased 29% during milking. Epinephrine decreased mammary blood flow by 90 to 95%. Oxytocin doses increased mammary blood flow by 15 to 24%. PMID:2674232

  20. Three-dimensional flow measurements in a tesla turbine rotor

    NASA Astrophysics Data System (ADS)

    Fuchs, Thomas; Schosser, Constantin; Hain, Rainer; Kaehler, Christian

    2015-11-01

    Tesla turbines are fluid mechanical devices converting flow energy into rotation energy by two physical effects: friction and adhesion. The advantages of the tesla turbine are its simple and robust design, as well as its scalability, which makes it suitable for custom power supply solutions, and renewable energy applications. To this day, there is a lack of experimental data to validate theoretical studies, and CFD simulations of these turbines. This work presents a comprehensive analysis of the flow through a tesla turbine rotor gap, with a gap height of only 0.5 mm, by means of three-dimensional Particle Tracking Velocimetry (3D-PTV). For laminar flows, the experimental results match the theory very well, since the measured flow profiles show the predicted second order parabolic shape in radial direction and a fourth order behavior in circumferential direction. In addition to these laminar measurements, turbulent flows at higher mass flow rates were investigated.

  1. Measurement and control of pressure driven flows in microfluidic devices using an optofluidic flow sensor

    PubMed Central

    Cheri, Mohammad Sadegh; Shahraki, Hamidreza; Sadeghi, Jalal; Moghaddam, Mohammadreza Salehi; Latifi, Hamid

    2014-01-01

    Measurement and control of pressure-driven flow (PDF) has a great potential to enhance the performance of chemical and biological experiments in Lab on a Chip technology. In this paper, we present an optofluidic flow sensor for real-time measurement and control of PDF. The optofluidic flow sensor consists of an on-chip micro Venturi and two optical Fabry-Pérot (FP) interferometers. Flow rate was measured from the fringe shift of FP interferometers resulted from movement fluid in the on-chip micro Venturi. The experimental results show that the optofluidic flow sensor has a minimum detectable flow change of 5 nl/min that is suitable for real time monitoring and control of fluids in many chemical and biological experiments. A Finite Element Method is used to solve the three dimensional (3D) Navier–Stokes and continuity equations to validate the experimental results. PMID:25584118

  2. Measures of intermittency in driven supersonic flows

    NASA Astrophysics Data System (ADS)

    Porter, D.; Pouquet, A.; Woodward, P.

    2002-08-01

    Scaling exponents for structure functions of the velocity, density, and entropy are computed for driven supersonic flows for rms Mach numbers of order unity, with numerical simulations using the piecewise parabolic method algorithm on grids of up to 5123 points. The driving is made up of either one or three orthogonal shear waves. In all cases studied, the compressible component of the velocity in the statistically steady regime is weaker than its solenoidal counterpart by roughly a factor of 6. Exponents for the longitudinal component of the velocity are comparable to what is found in the incompressible case and appear insensitive to the presence of numerous shocks. Scaling exponents of the transverse components of the velocity are comparable to those for the longitudinal component. Density and entropy structure functions display strong departures from linear scaling. Finally, the scaling of structure functions of the energy transfer is also given and compared with the Kolmogorov refined similarity hypothesis.

  3. Microwave/Sonic Apparatus Measures Flow and Density in Pipe

    NASA Technical Reports Server (NTRS)

    Arndt, G. D.; Ngo, Phong; Carl, J. R.; Byerly, Kent A.

    2004-01-01

    An apparatus for measuring the rate of flow and the mass density of a liquid or slurry includes a special section of pipe instrumented with microwave and sonic sensors, and a computer that processes digitized readings taken by the sensors. The apparatus was conceived specifically for monitoring a flow of oil-well-drilling mud, but the basic principles of its design and operation are also applicable to monitoring flows of other liquids and slurries.

  4. In-situ measurements of lunar heat flow

    NASA Technical Reports Server (NTRS)

    Langseth, M. G.; Keihm, S. J.

    1974-01-01

    During the Apollo program two successful heat flow measurements were made in situ on the lunar surface. At the Apollo 15 site a value of 0.0000031 watts/sqcm was measured and at the Apollo 17 site a value of 0.0000022 watts/sqcm was determined. Both measurements have uncertainty limits of + or - 20% and have been corrected for perturbing topographic effects. The apparent difference between the observations may correlate with observed variations in the surface abundance of thorium. Comparison with earlier determinations of heat flow, using the microwave emission spectrum from the moon, gives support to the high gradients and heat flows observed in situ.

  5. In-situ measurements of lunar heat flow

    NASA Technical Reports Server (NTRS)

    Langseth, M. B.; Keihm, S. J.

    1977-01-01

    During the Apollo program two successful heat flow measurements were made in situ on the lunar surface. At the Apollo 15 site a value of .0000031 W/sq cm was measured, and at the Apollo 17 site a value of .0000022 W/sq cm was determined. Both measurements have uncertainty limits of + or - 20 percent and have been corrected for perturbing topographic effects. The apparent difference between the observations may correlate with observed variations in the surface abundance of thorium. Comparison with earlier determinations of heat flow, using the microwave emission spectrum from the moon, gives support to the high gradients and heat flows observed in situ.

  6. Volumetric liquid flow measurement through thermography to simulate blood flow in an artery

    NASA Astrophysics Data System (ADS)

    Villaseñor-Mora, Carlos; Rabell-Montiel, Adela; González-Vega, Arturo; Gutierrez-Juarez, Gerardo

    2015-09-01

    Encouraged to improve the procedure to measure the blood flow in cases with peripheral artery disease using thermography, that allows to evaluate several arteries simultaneously, it was developed an alternative to measure the volumetric flow through a conduit, it was studied the variation of the thermal energy computed from thermal images due to changes in flow at different temperatures, and it was observed that the measurement is not strongly influenced by the emissivity of the conduit, the ambient temperature and humidity, but that is necessary to establish an adequate calibration of the camera to can use it as measurement instrument.

  7. Reynolds shear stress measurements in a separated boundary layer flow

    NASA Technical Reports Server (NTRS)

    Driver, David M.

    1991-01-01

    Turbulence measurements were obtained for two cases of boundary layer flow with an adverse pressure gradient, one attached and the other separated. A three-component laser Doppler velocimeter system was used to measure three mean velocity components, all six Reynolds stress components, and all ten velocity triple product correlations. Independent measurements of skin-friction obtained with a laser oil-flow interferometer were used to examine the law of the wall in adverse pressure gradient flows where p(+) is less than 0.05. Strong similiarities were seen between the two adverse pressure gradient flows and free shear layer type flows. Eddy viscosities, dissipation rates, and pressure-strain rates were deduced from the data and compared to various turbulence modeling assumptions.

  8. AUTOMATED TECHNIQUE FOR FLOW MEASUREMENTS FROM MARIOTTE RESERVOIRS.

    USGS Publications Warehouse

    Constantz, Jim; Murphy, Fred

    1987-01-01

    The mariotte reservoir supplies water at a constant hydraulic pressure by self-regulation of its internal gas pressure. Automated outflow measurements from mariotte reservoirs are generally difficult because of the reservoir's self-regulation mechanism. This paper describes an automated flow meter specifically designed for use with mariotte reservoirs. The flow meter monitors changes in the mariotte reservoir's gas pressure during outflow to determine changes in the reservoir's water level. The flow measurement is performed by attaching a pressure transducer to the top of a mariotte reservoir and monitoring gas pressure changes during outflow with a programmable data logger. The advantages of the new automated flow measurement techniques include: (i) the ability to rapidly record a large range of fluxes without restricting outflow, and (ii) the ability to accurately average the pulsing flow, which commonly occurs during outflow from the mariotte reservoir.

  9. Flow cytometry: A powerful technology for measuring biomarkers

    SciTech Connect

    Jett, J.H.

    1994-09-01

    A broad definition of a biomarker is that it is a measurable characteristic of a biological system that changes upon exposure to a physical or chemical insult. While the definition can be further refined, it is sufficient for the purposes of demonstrating the advantages of flow cytometry for making quantitative measurements of biomarkers. Flow cytometry and cell sorting technologies have emerged during the past 25 years to take their place alongside other essential tools used in biology such as optical and electron microscopy. This paper describes the basics of flow cytometry technology, provides illustrative examples of applications of the technology in the field of biomarkers, describes recent developments in flow cytometry that have not yet been applied to biomarker measurements, and projects future developments of the technology. The examples of uses of flow cytometry for biomarker quantification cited in this paper are meant to be illustrative and not exhaustive in the sense of providing a review of the field.

  10. Aerothermodynamic Facilities And Measurement: Flow Characterization in Shock Tunnels

    NASA Technical Reports Server (NTRS)

    Cavolowsky, John A.; Edwards, Thomas A. (Technical Monitor)

    1995-01-01

    This presentation will examine the key performance aspects of shock tunnels as they relate to their use as aerothermodynamic flow simulation facilities. Assessment of shock tube reservoir conditions and flow contaminants generated in the shock tube will be presented along with their limiting impact on viable test envelopes, Facility nozzle performance as it pertains to test time assessment and nozzle exit flow quality (survey of pressure, temperature, and species) will be addressed. Also included will be a discussion of free stream flow diagnostics, both intrusive and nonintrusive, for measurement of critical flow properties not directly inferred from surface mounted transducers. The use of computational fluid dynamics for purposes of validating experimental measurements as well as predicting performance in regimes where measurements are not feasible or possible will be discussed. The use of CFD for facility research and design will also be presented.

  11. One dimensional wavefront sensor development for tomographic flow measurements

    SciTech Connect

    Neal, D.; Pierson, R.; Chen, E.

    1995-08-01

    Optical diagnostics are extremely useful in fluid mechanics because they generally have high inherent bandwidth, and are non-intrusive. However, since optical probe measurements inherently integrate all information along the optical path, it is often difficult to isolate out-of-plane components in 3-dimensional flow events. It is also hard to make independent measurements of internal flow structure. Using an arrangement of one-dimensional wavefront sensors, we have developed a system that uses tomographic reconstruction to make two-dimensional measurements in an arbitrary flow. These measurements provide complete information in a plane normal to the flow. We have applied this system to the subsonic free jet because of the wide range of flow scales available. These measurements rely on the development of a series of one-dimensional wavefront sensors that are used to measure line-integral density variations in the flow of interest. These sensors have been constructed using linear CCD cameras and binary optics lenslet arrays. In designing these arrays, we have considered the coherent coupling between adjacent lenses and have made comparisons between theory and experimental noise measurements. The paper will present examples of the wavefront sensor development, line-integral measurements as a function of various experimental parameters, and sample tomographic reconstructions.

  12. Measurements of a stator-induced circumferentially varying flow

    NASA Astrophysics Data System (ADS)

    Farnsworth, John; Amitay, Michael; Beal, David; Huyer, Stephen A.

    2011-08-01

    The flow physics associated with the generation of both axisymmetric and non-axisymmetric swirl by various deflection patterns of a stator array was investigated experimentally through surface pressure and Stereoscopic Particle Image Velocimetry measurements. A three-dimensional rendering technique was developed to reconstruct the flow field around the model and in its wake. The three-dimensional fluid volume was reconstructed from multiple two-dimensional measurement planes. A cyclic distribution of the stators' deflections resulted in non-axisymmetric distributions of the surface pressure and the flow field downstream of the stator array. The addition of a shroud had an amplifying effect: accelerating the flow through the stator array while reducing the non-uniform tangential velocity component generated by the stators. In the model near wake the flow field is associated with secondary flow patterns in the form of coherent streamwise vortical structures that can be described by potential flow mechanisms. The collective pitch distribution of the stators produces a flow field that resembles a potential Rankine vortex, whereas the cyclic pitch distribution generates a flow pattern that can be described by a potential vortex pair in a cross-flow.

  13. 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).

  14. Device accurately measures and records low gas-flow rates

    NASA Technical Reports Server (NTRS)

    Branum, L. W.

    1966-01-01

    Free-floating piston in a vertical column accurately measures and records low gas-flow rates. The system may be calibrated, using an adjustable flow-rate gas supply, a low pressure gage, and a sequence recorder. From the calibration rates, a nomograph may be made for easy reduction. Temperature correction may be added for further accuracy.

  15. Flow among Musicians: Measuring Peak Experiences of Student Performers

    ERIC Educational Resources Information Center

    Sinnamon, Sarah; Moran, Aidan; O'Connell, Michael

    2012-01-01

    "Flow" is a highly coveted yet elusive state of mind that is characterized by complete absorption in the task at hand as well as by enhanced skilled performance. Unfortunately, because most measures of this construct have been developed in physical activity and sport settings, little is known about the applicability of flow scales to the…

  16. Crustal heat flow measurements in western Anatolia from borehole equilibrium temperatures

    NASA Astrophysics Data System (ADS)

    Erkan, K.

    2014-01-01

    Results of a crustal heat flow analysis in western Anatolia based on borehole equilibrium temperatures and rock thermal conductivity data are reported. The dataset comprises 113 borehole sites that were collected in Southern Marmara and Aegean regions of Turkey in 1995-1999. The measurements are from abandoned water wells with depths of 100-150 m. Data were first classed in terms of quality, and the low quality data, including data showing effects of hydrologic disturbances on temperatures, were eliminated. For the remaining 34 sites, one meter resolution temperature-depth curves were carefully analyzed for determination of the background geothermal gradients, and any effects of terrain topography and intra-borehole fluid flow were corrected when necessary. Thermal conductivities were determined either by direct measurements on representative surface outcrop or estimated from the borehole lithologic records. The calculated heat flow values are 85-90 mW m-2 in the northern and central parts of the Menderes horst-graben system. Within the system, the highest heat flow values (> 100 mW m-2) are observed in the northeastern part of Gediz Graben, near Kula active volcanic center. The calculated heat flow values are also in agreement with the results of studies on the maximum depth of seismicity in the region. In the Menderes horst-graben system, surface heat flow is expected to show significant variations as a result of active sedimentation and thermal refraction in grabens, and active erosion on horst detachment zones. High heat flow values (90-100 mW m-2) are also observed in the peninsular (western) part of Çanakkale province. The heat flow anomaly here may be an extension of the high heat flow zone previously observed in the northern Aegean Sea. Moderate heat flow values (60-70 mW m-2) are observed in eastern part of Çanakkale and central part of Balıkesir provinces.

  17. PIV measurements of flow in a centrifugal blood pump: steady flow.

    PubMed

    Day, Steven W; McDaniel, James C

    2005-04-01

    Magnetically suspended left ventricular assist devices have only one moving part, the impeller. The impeller has absolutely no contact with any of the fixed parts, thus greatly reducing the regions of stagnant or high shear stress that surround a mechanical or fluid bearing. Measurements of the mean flow patterns as well as viscous and turbulent stresses were made in a shaft-driven prototype of a magnetically suspended centrifugal blood pump at several constant flow rates (3-9 L/min) using particle image velocimetry (PIV). The chosen range of flow rates is representative of the range over which the pump may operate while implanted. Measurements on a three-dimensional measurement grid within several regions of the pump, including the inlet, blade passage, exit volute, and diffuser are reported. The measurements are used to identify regions of potential blood damage due to high shear stress and/or stagnation of the blood, both of which have been associated with blood damage within artificial heart valves and diaphragm-type pumps. Levels of turbulence intensity and Reynolds stresses that are comparable to those in artificial heart valves are reported. At the design flow rate (6 L/min), the flow is generally well behaved (no recirculation or stagnant flow) and stress levels are below levels that would be expected to contribute to hemolysis or thrombosis. The flow at both high (9 L/min) and low (3 L/min) flow rates introduces anomalies into the flow, such as recirculation, stagnation, and high stress regions. Levels of viscous and Reynolds shear stresses everywhere within the pump are below reported threshold values for damage to red cells over the entire range of flow rates investigated; however, at both high and low flow rate conditions, the flow field may promote activation of the clotting cascade due to regions of elevated shear stress adjacent to separated or stagnant flow. PMID:15971702

  18. PIV measurements of flow in a centrifugal blood pump: time-varying flow.

    PubMed

    Day, Steven W; McDaniel, James C

    2005-04-01

    Measurements of the time-varying flow in a centrifugal blood pump operating as a left ventricular assist device (LVAD) are presented. This includes changes in both the pump flow rate as a function of the left ventricle contraction and the interaction of the rotating impeller and fixed exit volute. When operating with a pulsing ventricle, the flow rate through the LVAD varies from 0-11 L/min during each cycle of the heartbeat. Phase-averaged measurements of mean velocity and some turbulence statistics within several regions of the pump, including the inlet, blade passage, exit volute, and diffuser, are reported at 20 phases of the cardiac cycle. The transient flow fields are compared to the constant flow rate condition that was reported previously in order to investigate the transient effects within the pump. It is shown that the quasi-steady assumption is a fair treatment of the time varying flow field in all regions of this representative pump, which greatly simplifies the comprehension and modeling of this flow field. The measurements are further interpreted to identify the effects that the transient nature of the flow field will have on blood damage. Although regions of recirculation and stagnant flow exist at some phases of the cardiac cycle, there is no location where flow is stagnant during the entire heartbeat. PMID:15971703

  19. Pulsatile flow simulator for comparison of cardiac output measurements by electromagnetic flow meter and thermodilution.

    PubMed

    Jebson, P J; Karkow, W S

    1986-01-01

    This study examined a pulsatile flow simulator for the purpose of evaluating two measurement devices, an extracorporeal flow probe with an electromagnetic flow meter and several thermodilution catheters. We measured the performance of these devices in a range of low to high flows. Using either saline or blood as a perfusate, we obtained different results with these fluids (p less than 0.001). Each catheter behaved in a linear manner, although variation occurred among the catheters with both saline (minimum slope 1.090, maximum slope 1.190) and blood (minimum slope 1.107, maximum slope 1.154). An increase in rate and stroke volumes of the simulator did not demonstrate an identifiable trend in error. The thermodilution catheters were most accurate at 5.0 L/min irrespective of rate, stroke volume, or perfusate used. In contrast, the electromagnetic flow meter accurately represented flows across the wide range of outputs examined (2.4 to 10.7 L/min). (Slope with saline 1.091, slope with blood 1.080) Throughout the range of flow, the flow meter gave a calibration line 5% higher with blood than with saline. The results indicate that accurate measurement of pulsatile blood flow can be achieved in vitro with an electromagnetic flow meter using saline as a perfusate, provided a correction factor is determined and applied to convert values for saline to accurate values for blood. PMID:2940345

  20. Laboratory measurement and interpretation of nonlinear gas flow in shale

    NASA Astrophysics Data System (ADS)

    Kang, Yili; Chen, Mingjun; Li, Xiangchen; You, Lijun; Yang, Bin

    2015-11-01

    Gas flow mechanisms in shale are urgent to clarify due to the complicated pore structure and low permeability. Core flow experiments were conducted under reservoir net confining stress with samples from the Longmaxi Shale to investigate the characteristics of nonlinear gas flow. Meanwhile, microstructure analyses and gas adsorption experiments are implemented. Experimental results indicate that non-Darcy flow in shale is remarkable and it has a close relationship with pore pressure. It is found that type of gas has a significant influence on permeability measurement and methane is chosen in this work to study the shale gas flow. Gas slippage effect and minimum threshold pressure gradient weaken with the increasing backpressure. It is demonstrated that gas flow regime would be either slip flow or transition flow with certain pore pressure and permeability. Experimental data computations and microstructure analyses confirm that hydraulic radius of flow tubes in shale are mostly less than 100 nm, indicating that there is no micron scale pore or throat which mainly contributes to flow. The results are significant for the study of gas flow in shale, and are beneficial for laboratory investigation of shale permeability.

  1. Measuring two phase flow parameters using impedance cross-correlation flow meter

    NASA Astrophysics Data System (ADS)

    Muhamedsalih, Y.; Lucas, G.

    2012-03-01

    This paper describes the design and implementation of an impedance cross correlation flow meter which can be used in solids-water pipe flows to measure the local solids volume fraction distribution and the local solids velocity distribution. The system is composed of two arrays of electrodes, separated by an axial distance of 50 mm and each array contains eights electrodes mounted over the internal circumference of the pipe carrying the flow. Furthermore every electrode in each array can be selected to be either"excitation", "measurement" or "earth". Changing the electrode configuration leads to a change in the electric field, and hence in the region of the flow cross section which is interrogated. The local flow velocity in the interrogated region is obtained by cross correlation between the two electrode arrays. Additionally, the local solids volume fraction can be obtained from the mean mixture conductivity in the region under interrogation. The system is being integrated with a microcontroller to measure the velocity distribution of the solids and the volume fraction distribution of the solids in order to create a portable flow meter capable of measuring the multi-phase flow parameters without the need of a PC to control it. Integration of the product of the local solids volume fraction and the local solids velocity in the flow cross section enables the solids volumetric flow rate to be determined.

  2. Measurements of granular flow dynamics with high speed digital images

    SciTech Connect

    Lee, J.

    1994-12-31

    The flow of granular materials is common to many industrial processes. This dissertation suggests and validates image processing algorithms applied to high speed digital images to measure the dynamics (velocity, temperature and volume fraction) of dry granular solids flowing down an inclined chute under the action of gravity. Glass and acrylic particles have been used as granular solids in the experiment. One technique utilizes block matching for spatially averaged velocity measurements of the glass particles. This technique is compared with the velocity measurement using an optic probe which is a conventional granular flow velocity measurement device. The other technique for measuring the velocities of individual acrylic particles is developed with correspondence using a Hopfield network. This technique first locates the positions of particles with pattern recognition techniques, followed by a clustering technique, which produces point patterns. Also, several techniques are compared for particle recognition: synthetic discriminant function (SDF), minimum average correlation energy (MACE) filter, modified minimum average correlation energy (MMACE) filter and variance normalized correlation. The author proposes an MMACE filter which improves generalization of the MACE filter by adjusting the amount of averaged spectrum of training images in the spectrum whitening stages of the MACE filter. Variance normalized correlation is applied to measure the velocity and temperature of flowing glass particles down the inclined chute. The measurements are taken for the steady and wavy flow and qualitatively compared with a theoretical model of granular flow.

  3. Effect of voluntary hyperventilation with supplemental CO2 on pulmonary O2 uptake and leg blood flow kinetics during moderate-intensity exercise.

    PubMed

    Chin, Lisa M K; Heigenhauser, George J F; Paterson, Donald H; Kowalchuk, John M

    2013-12-01

    Pulmonary O2 uptake (V(O₂p)) and leg blood flow (LBF) kinetics were examined at the onset of moderate-intensity exercise, during hyperventilation with and without associated hypocapnic alkalosis. Seven male subjects (25 ± 6 years old; mean ± SD) performed alternate-leg knee-extension exercise from baseline to moderate-intensity exercise (80% of estimated lactate threshold) and completed four to six repetitions for each of the following three conditions: (i) control [CON; end-tidal partial pressure of CO2 (P(ET, CO₂)) ~40 mmHg], i.e. normal breathing with normal inspired CO2 (0.03%); (ii) hypocapnia (HYPO; P(ET, CO₂) ~20 mmHg), i.e. sustained hyperventilation with normal inspired CO2 (0.03%); and (iii) normocapnia (NORMO; P(ET, CO₂) ~40 mmHg), i.e. sustained hyperventilation with elevated inspired CO2 (~5%). The V(O₂p) was measured breath by breath using mass spectrometry and a volume turbine. Femoral artery mean blood velocity was measured by Doppler ultrasound, and LBF was calculated from femoral artery diameter and mean blood velocity. Phase 2 V(O₂p) kinetics (τV(O₂p)) was different (P < 0.05) amongst all three conditions (CON, 19 ± 7 s; HYPO, 43 ± 17 s; and NORMO, 30 ± 8 s), while LBF kinetics (τLBF) was slower (P < 0.05) in HYPO (31 ± 9 s) compared with both CON (19 ± 3 s) and NORMO (20 ± 6 s). Similar to previous findings, HYPO was associated with slower V(O₂p) and LBF kinetics compared with CON. In the present study, preventing the fall in end-tidal P(CO₂) (NORMO) restored LBF kinetics, but not V(O₂p) kinetics, which remained 'slowed' relative to CON. These data suggest that the hyperventilation manoeuvre itself (i.e. independent of induced hypocapnic alkalosis) may contribute to the slower V(O₂p) kinetics observed during HYPO. PMID:23975901

  4. Measurement of directed blood flow by laser speckle

    NASA Astrophysics Data System (ADS)

    Hirst, Evan R.; Thompson, Oliver B.; Andrews, Michael K.

    2011-03-01

    Recent success in reconciling laser Doppler and speckle measurements of dermal perfusion by the use of multi-exposure speckle has prompted an investigation of speckle effects arising from directed blood flow which might be expected in the small blood vessels of the eye. Unlike dermal scatter, the blood in retinal vessels is surrounded by few small and stationary scatterers able to assist the return of light energy by large-angle scatter. Returning light is expected to come from multiple small angle scatter from the large red blood cells which dominate the fluid. This work compares speckle measurements on highly scattering skin, with measurements on flow in a retinal phantom consisting of a glass capillary which is itself immersed in an index matching fluid to provide a flat air-phantom interface. Brownian motion dominated measurements when small easily levitated scatters were used, and flow was undetectable. With whole-blood, Brownian motion was small and directed flows in the expected region of tens of mm/s were detectable. The nominal flow speed relates to the known pump rate; within the capillary the flow will have a profile reducing toward the walls. The pulsatile effects on laser speckle contrast in the retina are discussed with preliminary multi-exposure measurements on retinal vessels using a fundus camera. Differences between the multiple exposure curves and power spectra of perfused tissue and ordered flow are discussed.

  5. 40 CFR 86.314-79 - Fuel flow measurement specifications.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... volume flow and density, the error in the actual volume consumed must not be greater than ±1 percent of... (electronic weight, volume, density, etc.), measurements may not be used for calculations if the...

  6. Stereoscopic PIV measurements of swirling flow entering a catalyst substrate

    SciTech Connect

    Persoons, T.; Vanierschot, M.; Van den Bulck, E.

    2008-09-15

    This experimental study investigates the stagnation region of a swirling flow entering an automotive catalyst substrate. A methodology is established using stereoscopic particle image velocimetry (PIV) to determine three-component velocity distributions up to 0.2 mm from the catalyst entrance face. In adverse conditions of strong out-of-plane velocity, PIV operating parameters are adjusted for maximum spatial correlation strength. The measurement distance to the catalyst is sufficiently small to observe radial flow spreading. A scaling analysis of the stagnation flow region provides a model for the flow uniformization as a function of the catalyst pressure drop. (author)

  7. Enhanced Oil Recovery: Aqueous Flow Tracer Measurement

    SciTech Connect

    Joseph Rovani; John Schabron

    2009-02-01

    A low detection limit analytical method was developed to measure a suite of benzoic acid and fluorinated benzoic acid compounds intended for use as tracers for enhanced oil recovery operations. Although the new high performance liquid chromatography separation successfully measured the tracers in an aqueous matrix at low part per billion levels, the low detection limits could not be achieved in oil field water due to interference problems with the hydrocarbon-saturated water using the system's UV detector. Commercial instrument vendors were contacted in an effort to determine if mass spectrometry could be used as an alternate detection technique. The results of their work demonstrate that low part per billion analysis of the tracer compounds in oil field water could be achieved using ultra performance liquid chromatography mass spectrometry.

  8. Stereoscopic PIV measurements of flow in the nasal cavity with high flow therapy

    NASA Astrophysics Data System (ADS)

    Spence, C. J. T.; Buchmann, N. A.; Jermy, M. C.; Moore, S. M.

    2011-04-01

    Knowledge of the airflow characteristics within the nasal cavity with nasal high flow (NHF) therapy and during unassisted breathing is essential to understand the treatment's efficacy. The distribution and velocity of the airflow in the nasal cavity with and without NHF cannula flow has been investigated using stereoscopic particle image velocimetry at steady peak expiration and inspiration. In vivo breathing flows were measured and dimensionally scaled to reproduce physiological conditions in vitro. A scaled model of the complete nasal cavity was constructed in transparent silicone and airflow simulated with an aqueous glycerine solution. NHF modifies nasal cavity flow patterns significantly, altering the proportion of inspiration and expiration through each passageway and producing jets with in vivo velocities up to 17.0 ms-1 for 30 l/min cannula flow. Velocity magnitudes differed appreciably between the left and right sides of the nasal cavity. The importance of using a three-component measurement technique when investigating nasal flows has been highlighted.

  9. In vitro flow measurements in ion sputtered hydrocephalus shunts

    NASA Technical Reports Server (NTRS)

    Cho, Y. I.; Back, L. H.

    1989-01-01

    This paper describes an experimental procedure for accurate measurements of the pressure-drop/flow rate relationship in hydrocephalus shunts. Using a fish-hook arrangement, small flow rates in a perforated ion-sputtered Teflon microtubule were measured in vitro in a pressured system and were correlated with pressure in the system. Results indicate that appropriate drainage rates could be obtained in the physiological range for hydrocephalus shunts.

  10. Blood-flow measurement in muscle with Xe-133

    SciTech Connect

    Chung, S.Y.; Kim, I.; Ryo, U.Y.; Maskin, C.; Pinsky, S.

    1987-11-01

    An alternative method to the conventional miniature probe system for the measurement of blood flow in muscle has been developed. Xenon-133 was injected into the quadriceps muscles of ten subjects. A gamma camera and an online computer were then used to measure the half-clearance time of the Xe-133 while the subject was both at rest and exercising on an upright bicycle ergometer. The blood flow in the muscle was then calculated from the acquired data.

  11. Wear Testing of Moderate Activities of Daily Living Using In Vivo Measured Knee Joint Loading

    PubMed Central

    Reinders, Jörn; Sonntag, Robert; Vot, Leo; Gibney, Christian; Nowack, Moritz; Kretzer, Jan Philippe

    2015-01-01

    Resumption of daily living activities is a basic expectation for patients provided with total knee replacements. However, there is a lack of knowledge regarding the impact of different activities on the wear performance. In this study the wear performance under application of different daily activities has been analyzed. In vivo load data for walking, walking downstairs/upstairs, sitting down/standing up, and cycling (50 W & 120 W) has been standardized for wear testing. Wear testing of each activity was carried out on a knee wear simulator. Additionally, ISO walking was tested for reasons of comparison. Wear was assessed gravimetrically and wear particles were analyzed. In vivo walking produced the highest overall wear rates, which were determined to be three times higher than ISO walking. Moderate wear rates were determined for walking upstairs and downstairs. Low wear rates were determined for standing up/sitting down and cycling at power levels of 50 W and 120 W. The largest wear particles were observed for cycling. Walking based on in vivo data has been shown to be the most wear-relevant activity. Highly demanding activities (stair climbing) produced considerably less wear. Taking into account the expected number of loads, low-impact activities like cycling may have a greater impact on articular wear than highly demanding activities. PMID:25811996

  12. Measuring tissue blood flow using ultrasound modulated diffused light

    NASA Astrophysics Data System (ADS)

    Ron, A.; Racheli, N.; Breskin, I.; Metzger, Y.; Silman, Z.; Kamar, M.; Nini, A.; Shechter, R.; Balberg, M.

    2012-02-01

    We demonstrate the ability of a novel device employing ultrasound modulation of near infrared light (referred as "Ultrasound tagged light" or UTL) to perform non-invasive monitoring of blood flow in the microvascular level in tissue. Monitoring microcirculatory blood flow is critical in clinical situations affecting flow to different organs, such as the brain or the limbs. . However, currently there are no non-invasive devices that measure microcirculatory blood flow in deep tissue continuously. Our prototype device (Ornim Medical, Israel) was used to monitor tissue blood flow on anesthetized swine during controlled manipulations of increased and decreased blood flow. Measurements were done on the calf muscle and forehead of the animal and compared with Laser Doppler (LD). ROC analysis of the sensitivity and specificity for detecting an increase in blood flow on the calf muscle, demonstrated AUC = 0.951 for 23 systemic manipulations of cardiac output by Epinephrine injection, which is comparable to AUC = 0.943 using laser Doppler. Some examples of cerebral blood flow monitoring are presented, along with their individual ROC curves. UTL flowmetry is shown to be effective in detecting changes in cerebral and muscle blood flow in swine, and has merit in clinical applications.

  13. Flap survey test of a combined surface blowing model: Flow measurements at static flow conditions

    NASA Technical Reports Server (NTRS)

    Fukushima, T.

    1978-01-01

    The Combined Surface Blowing (CSB) V/STOL lift/propulsion system consists of a blown flap system which deflects the exhaust from a turbojet engine over a system of flaps deployed at the trailing edge of the wing. Flow measurements consisting of velocity measurements using split film probes and total measure surveys using a miniature Kiel probe were made at control stations along the flap systems at two spanwise stations, the centerline of the nozzle and 60 percent of the nozzle span outboard of the centerline. Surface pressure measurements were made in the wing cove and the upper surface of the first flap element. The test showed a significant flow separation in the wing cove. The extent of the separation is so large that the flow into the first flap takes place only at the leading edge of the flap. The velocity profile measurements indicate that large spanwise (3 dimensional) flow may exist.

  14. Flow measurements in a water tunnel using a holocinematographic velocimeter

    NASA Astrophysics Data System (ADS)

    Weinstein, Leonard M.; Beeler, George B.

    1987-06-01

    Dual-view holographic movies were used to examine complex flows with full three-space and time resolution. This approach, which tracks the movement of small tracer particles in water, is termed holocinematographic velocimetry (HCV). A small prototype of a new water tunnel was used to demonstrate proof-of-concept for the HCV. After utilizing a conventional flow visualization apparatus with a laser light sheet to illuminate tracer particles to evaluate flow quality of the prototype tunnel, a simplified version of the HCV was employed to demonstrate the capabilities of the approach. Results indicate that a full-scale version of the water tunnel and a high performance version of the HCV should be able to check theoretical and numerical modeling of complex flows and examine the mechanisms operative in turbulent and vortex flow control concepts, providing an entirely unique instrument capable, for the first time, of simultaneous three-space and time measurements in turbulent flow.

  15. Retinal blood flow measurement by using optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Makita, Shuichi; Fabritius, Tapio; Miura, Masahiro; Yatagai, Toyohiko; Yasuno, Yoshiaki

    2008-02-01

    Quantification of the three-dimensional (3D) retinal vessel structure and blood flow is demonstrated. 3D blood flow distribution is obtained by Doppler optical coherence angiography (D-OCA). Vessel parameters, i.e. diameter, orientation, and position, are determined in an en face vessel image. The Doppler angle is estimated as the angle between the retinal vessel and the incident probing beam in representative cross-sectional flow image which extracted from the 3D flow distribution according to the vessel parameters. Blood flow velocity and volume rate can be quantified with these vessel parameters. The retinal blood flow velocity and volume rate are measured in the retinal vessels around the optic nerve head.

  16. Flow measurements in a water tunnel using a holocinematographic velocimeter

    NASA Technical Reports Server (NTRS)

    Weinstein, Leonard M.; Beeler, George B.

    1987-01-01

    Dual-view holographic movies were used to examine complex flows with full three-space and time resolution. This approach, which tracks the movement of small tracer particles in water, is termed holocinematographic velocimetry (HCV). A small prototype of a new water tunnel was used to demonstrate proof-of-concept for the HCV. After utilizing a conventional flow visualization apparatus with a laser light sheet to illuminate tracer particles to evaluate flow quality of the prototype tunnel, a simplified version of the HCV was employed to demonstrate the capabilities of the approach. Results indicate that a full-scale version of the water tunnel and a high performance version of the HCV should be able to check theoretical and numerical modeling of complex flows and examine the mechanisms operative in turbulent and vortex flow control concepts, providing an entirely unique instrument capable, for the first time, of simultaneous three-space and time measurements in turbulent flow.

  17. Measuring Photospheric Rotational and Meridional Flows Using Magnetic Feature Tracking

    NASA Astrophysics Data System (ADS)

    Lamb, Derek

    2016-05-01

    Long-lived rotational and meridional flows are important ingredients of the solar cycle. Using magnetic field images to measure these flows on the solar surface has typically been performed by cross-correlating thin longitudinal strips or square patches across sufficiently long time gaps. Here, I use one month of SDO/HMI line-of-sight magnetic field observations, combined with the SWAMIS magnetic feature tracking algorithm to measure the motion of individual features in these magnetograms. By controlling for perturbations due to short-lived flows and due to false motions from feature interactions, I effectively isolate the long-lived flows traced by the magnetic features. This allows me to produce high-fidelity differential rotation measurements with well-characterized variances and covariances of the fit parameters. I also produce medium-fidelity measurements of the much weaker meridional flow that is broadly consistent with previous results, showing a peak flow of 16.7 m/s at 45 degrees latitude. This work shows that measuring the motions of individual features in photospheric magnetograms can produce high precision results in relatively short time spans, which suggests that high resolution non-longitudinally averaged photospheric velocity residual measurements could be produced to compare with coronal results, and to provide other diagnostics of the solar dynamo. This work has been partially supported by NASA Grants NNX11AP03G and NNX14AJ67G.

  18. Measurement of transitional flow in pipes using ultrasonic flowmeters

    NASA Astrophysics Data System (ADS)

    Zheng-Gang, Liu; Guang-Sheng, Du; Zhu-Feng, Shao; Qian-Ran, He; Chun-Li, Zhou

    2014-10-01

    The accuracy of an ultrasonic flowmeter depends on the ratio k of average profile velocity of pipe and average velocity of an ultrasonic propagation path. But there is no appropriate method of calculating k for transition flow. In this paper, the velocity field of the transition flow in a pipe is measured by particle image velocimetry. On this basis, the k of U-shaped and V-shaped ultrasonic flowmeter is obtained when Reynolds number is between 2000 and 20 000. It is shown that the k is constant when the Reynolds number is in the range of 2000-2400 and 5400-20 000, and the k decreases with the increasing of Re when the Reynolds number is 2400-5400. The results of study can be used to improve the measurement accuracy of ultrasonic flowmeters when flow is transition flow and can provide help for the study of pipe flow.

  19. PIV measurements of hydrodynamic interactions between biofilms and flow

    NASA Astrophysics Data System (ADS)

    Christensen, Kenneth T.; Kazemifar, Farzan; Aybar, Marcelo; Perez-Calleja, Patricia; Nerenberg, Robert; Sinha, Sumit; Hardy, Richard J.; Best, Jim L.; Sambrook Smith, Greg H.

    2015-11-01

    Biofilms constitute an important form of bacterial life in aquatic environments and are present at the interface of fluids and solid such as riverbeds or bridge columns. They are also utilized in bioreactors for bioremediation and water treatment purposes. They are permeable, heterogeneous, and deformable structures that can influence the flow and mass/momentum transport, yet their interaction with flow is not fully understood in part due to technical obstacles impeding quantitative experimental investigations. We have attempted to address these challenges using the PIV technique and fluorescence imaging to investigate the flow field around cylinders covered with biofilms at different growth stages. These measurements are meant to uncover the coupled dynamics of turbulence and the biofilm development. Preliminary results of PIV measurements of flow-biofilm interactions in channel flow will be presented.

  20. Cyclic Concentration Measurements for Characterizing Pulsating Flow

    SciTech Connect

    Bamberger, Judith A.

    2013-07-07

    Slurry mixed in vessels via pulse jet mixers has a periodic, rather than steady, concentration profile. Measurements of local concentration taken at the center of the tank at a range of elevations within the mixed region were analyzed to obtain a greater understanding of how the periodic pulse jet mixing cycle affects the local concentration. Data were obtained at the critical suspension velocity, when all solids are suspended at the end of the pulse. The data at a range of solids loadings are analyzed to observe the effect of solids concentration during the suspension and settling portions of the mixing cycle.

  1. Spatial and Numerical Predictors of Measurement Performance: The Moderating Effects of Community Income and Gender

    ERIC Educational Resources Information Center

    Casey, Beth M.; Dearing, Eric; Vasilyeva, Marina; Ganley, Colleen M.; Tine, Michele

    2011-01-01

    Spatial reasoning and numerical predictors of measurement performance were investigated in 4th graders from low-income and affluent communities. Predictors of 2 subtypes of measurement performance (spatial-conceptual and formula based) were assessed while controlling for verbal and spatial working memory. Consistent with prior findings, students…

  2. Guide to Flow Measurement for Electric Propulsion Systems

    NASA Technical Reports Server (NTRS)

    Frieman, Jason D.; Walker, Mitchell L. R.; Snyder, Steve

    2013-01-01

    In electric propulsion (EP) systems, accurate measurement of the propellant mass flow rate of gas or liquid to the thruster and external cathode is a key input in the calculation of thruster efficiency and specific impulse. Although such measurements are often achieved with commercial mass flow controllers and meters integrated into propellant feed systems, the variability in potential propellant options and flow requirements amongst the spectrum of EP power regimes and devices complicates meter selection, integration, and operation. At the direction of the Committee on Standards for Electric Propulsion Testing, a guide was jointly developed by members of the electric propulsion community to establish a unified document that contains the working principles, methods of implementation and analysis, and calibration techniques and recommendations on the use of mass flow meters in laboratory and spacecraft electric propulsion systems. The guide is applicable to EP devices of all types and power levels ranging from microthrusters to high-power ion engines and Hall effect thrusters. The establishment of a community standard on mass flow metering will help ensure the selection of the proper meter for each application. It will also improve the quality of system performance estimates by providing comprehensive information on the physical phenomena and systematic errors that must be accounted for during the analysis of flow measurement data. This paper will outline the standard methods and recommended practices described in the guide titled "Flow Measurement for Electric Propulsion Systems."

  3. A flow cytometer for the measurement of Raman spectra.

    PubMed

    Watson, Dakota A; Brown, Leif O; Gaskill, Daniel F; Naivar, Mark; Graves, Steven W; Doorn, Stephen K; Nolan, John P

    2008-02-01

    Multiparameter measurements in flow cytometry are limited by the broad emission spectra of fluorescent labels. By contrast, Raman spectra are notable for their narrow spectral features. To increase the multiparameter analysis capabilities of flow cytometry, we investigated the possibility of measuring Raman signals in a flow cytometry-based system. We constructed a Raman Spectral Flow Cytometer, substituting a spectrograph and CCD detector for the traditional mirrors, optical filters, and photomultiplier tubes. Excitation at 633 nm was provided by a HeNe laser, and forward-angle light scatter is used to trigger acquisition of complete spectra from individual particles. Microspheres were labeled with nanoparticle surface enhanced Raman scattering (SERS) tags and measured using the RSFC. Fluorescence and Raman spectra from labeled microspheres were acquired using the Raman Spectral Flow Cytometer. SERS spectral intensities were dependent on integration time, laser power, and detector pixel binning. Spectra from particles labeled with one each of four different SERS tags could be distinguished by either a virtual bandpass approach using commercial flow cytometry data analysis software or by principal component analysis. Raman flow cytometry opens up new possibilities for highly multiparameter and multiplexed measurements of cells and other particles using a simple optical design and a single detector and light source. PMID:18189283

  4. TECHNIQUES TO MEASURE VOLUMETRIC FLOW AND PARTICULATE CONCENTRATION IN STACKS WITH CYCLONIC FLOW

    EPA Science Inventory

    The study determined that an in-stack venturi can accurately measure volumetric flow in stacks with a severe cyclonic flow profile. The design requirements of the venturi are described in the report. The report also describes a low head loss, egg crate-shaped device that effectiv...

  5. Characterization of fracture permeability with high-resolution vertical flow measurements during borehole pumping.

    USGS Publications Warehouse

    Paillet, Frederick L.; Hess, A.E.; Cheng, C.H.; Hardin, E.

    1987-01-01

    The distribution of fracture permeability in granitic rocks was investigated by measuring the distribution of vertical flow in boreholes during periods of steady pumping. Pumping tests were conducted at two sites chosen to provide examples of moderately fractured rocks near Mirror Lake, New Hampshire and intensely fractured rocks near Oracle, Arizona. A sensitive heat-pulse flowmeter was used for accurate measurements of vertical flow as low as 0.2 liter per minute. Results indicate zones of fracture permeability in crystalline rocks are composed of irregular conduits that cannot be approximated by planar fractures of uniform aperture, and that the orientation of permeability zones may be unrelated to the orientation of individual fractures within those zones.-Authors

  6. In vitro validation of volumetric blood flow measurement using Doppler flow wire.

    PubMed

    Jenni, R; Kaufmann, P A; Jiang, Z; Attenhofer, C; Linka, A; Mandinov, L

    2000-10-01

    Determination of any volumetric blood flow requires assessment of mean blood flow velocity and vessel cross-sectional area. For evaluation of coronary blood flow and flow reserve, however, assessment of average peak velocity alone is widely used, but changes in velocity profile and vessel area are not taken into account. We studied the feasibility of a new method for calculation of volumetric blood flow by Doppler power using a Doppler flow wire. An in vitro model with serially connected silicone tubes of known lumen diameters (1.5, 2.0, 2.5, 3.0, 3.5 and 4.0 mm) and pulsatile blood flow ranging from 10 to 200 mL/min was used. A Doppler flow wire was connected to a commercially available Doppler system (FloMap(R), Cardiometrics) for online calculation of the zeroth (M(0)) and the first (M(1)) Doppler moment, as well as mean flow velocity (V(m)). Two different groups of sample volumes (at different gate depths) were used: 1. two proximal sample volumes lying completely within the vessel were required to evaluate the effect of scattering and attenuation on Doppler power, and 2. distal sample volumes intersecting completely the vessel lumen to assess the vessel cross-sectional area. Area (using M(0)) and V(m) (using M(1)/M(0)) obtained from the distal gates were corrected for scattering and attenuation by the data obtained from the proximal gates, allowing calculation of absolute volumetric flow. These results were compared to the respective time collected flow. Correlation between time collected and Doppler-derived flow measurements was 0.98 (p < 0.0001), with a regression line close to the line of equality indicating an excellent agreement of the two measurements in each individual tube. The mean paired flow difference between the two techniques was 1.5 +/- 9.0 mL/min (ns). Direct volumetric blood flow measurement from received Doppler power using a Doppler flow wire system is feasible. This technique may potentially be of great clinical value because it allows an

  7. Regional Skin Temperature Response to Moderate Aerobic Exercise Measured by Infrared Thermography

    PubMed Central

    Fernandes, Alex de Andrade; Amorim, Paulo Roberto dos Santos; Brito, Ciro José; Sillero-Quintana, Manuel; Bouzas Marins, João Carlos

    2016-01-01

    Background: Infrared thermography (IRT) does not require contact with the skin, and it is a convenient, reliable and non-invasive technique that can be used for monitoring the skin temperature (TSK). Objectives: The aim of this study was to monitor the variations in the regional TSK during exercise on 28 regions of interest (ROIs) (forehead, face, chest, abdomen, back, lumbar, anterior and posterior neck, and posterior and anterior views of the right and left hands, forearms, upper arms, thighs, and legs) with IRT. Patients and Methods: 12 physically active young males were monitored with IRT during the following three phases: a) 30 minutes before exercise b) while performing one hour of moderate intensity exercise on a treadmill at 60% of the VO2max, and c) 60 minutes after exercise. Results: During pre-exercise, all TSK reached a steady-state (P ≤ 0.05), which ensured adequate thermal stabilisation. At the beginning of exercise, there was a significant reduction in the TSK in most ROIs after 10 minutes of activity, except for the lower limbs (legs and thighs). After one hour of recovery, in the anterior view of the hands and thighs and in the posterior view of the legs, there were significant increases in the TSK compared to pre-exercise. Conclusions: There were significant distinctions in the skin temperature distribution during exercise according to the activity of the area under consideration during exercise, which may be important in the development of physiological models and heat flux analyses for different purposes. PMID:27217931

  8. Measurements of the tip-gap turbulent flow structure in a low-speed compressor cascade

    NASA Astrophysics Data System (ADS)

    Tang, Genglin

    This dissertation presents results from a thorough study of the tip-gap turbulent flow structure in a low-speed linear compressor cascade wind tunnel at Virginia Tech that includes a moving belt system to simulate the relative motion between the tip and the casing. The endwall pressure measurements and the surface oil flow visualizations were made on a stationary endwall to obtain the flow features and to determine the measurement profiles of interest. A custom-made miniature 3-orthogonal-velocity-component fiber-optic laser-Doppler velocimetry (LDV) system was used to measure all three components of velocity within a 50 mum spherical measurement volume within the gap between the endwall and the blade tip, mainly for the stationary wall with 1.65% and 3.30% tip gaps as well as some initial experiments for the moving wall. Since all of the vorticity in a flow originates from the surfaces under the action of strong pressure gradient, it was very important to measure the nearest-wall flow on the endwall and around the blade tip. The surface skin friction velocity was measured by using viscous sublayer velocity profiles, which verified the presence of an intense lateral shear layer that was observed from surface oil flow visualizations. All second- and third-order turbulence quantities were measured to provide detailed data for any parallel CFD efforts. The most complete data sets were acquired for 1.65% and 3.30% tip gap/chord ratios in a low-speed linear compressor cascade. This study found that tip gap flows are complex pressure-driven, unsteady three-dimensional turbulent flows. The crossflow velocity normal to the blade chord is nearly uniform in the and tip-gap and changes substantially from the pressure to suction side. The crossflow velocity relies on the local tip pressure loading that is different from the mid-span pressure loading because of tip leakage vortex influence. The tip gap flow is highly skewed three-dimensional flow throughout the full gap

  9. Thomson scattering measurements from asymmetric interpenetrating plasma flows.

    PubMed

    Ross, J S; Moody, J D; Fiuza, F; Ryutov, D; Divol, L; Huntington, C M; Park, H-S

    2014-11-01

    Imaging Thomson scattering measurements of collective ion-acoustic fluctuations have been utilized to determine ion temperature and density from laser produced counter-streaming asymmetric flows. Two foils are heated with 8 laser beams each, 500 J per beam, at the Omega Laser facility. Measurements are made 4 mm from the foil surface using a 60 J 2ω probe laser with a 200 ps pulse length. Measuring the electron density and temperature from the electron-plasma fluctuations constrains the fit of the multi-ion species, asymmetric flows theoretical form factor for the ion feature such that the ion temperatures, ion densities, and flow velocities for each plasma flow are determined. PMID:25430359

  10. Thomson scattering measurements from asymmetric interpenetrating plasma flows

    SciTech Connect

    Ross, J. S. Moody, J. D.; Fiuza, F.; Ryutov, D.; Divol, L.; Huntington, C. M.; Park, H.-S.

    2014-11-15

    Imaging Thomson scattering measurements of collective ion-acoustic fluctuations have been utilized to determine ion temperature and density from laser produced counter-streaming asymmetric flows. Two foils are heated with 8 laser beams each, 500 J per beam, at the Omega Laser facility. Measurements are made 4 mm from the foil surface using a 60 J 2ω probe laser with a 200 ps pulse length. Measuring the electron density and temperature from the electron-plasma fluctuations constrains the fit of the multi-ion species, asymmetric flows theoretical form factor for the ion feature such that the ion temperatures, ion densities, and flow velocities for each plasma flow are determined.

  11. Time-Resolved Rayleigh Scattering Measurements in Hot Gas Flows

    NASA Technical Reports Server (NTRS)

    Mielke, Amy F.; Elam, Kristie A.; Sung, Chih-Jen

    2008-01-01

    A molecular Rayleigh scattering technique is developed to measure time-resolved gas velocity, temperature, and density in unseeded gas flows at sampling rates up to 32 kHz. A high power continuous-wave laser beam is focused at a point in an air flow field and Rayleigh scattered light is collected and fiber-optically transmitted to the spectral analysis and detection equipment. The spectrum of the light, which contains information about the temperature and velocity of the flow, is analyzed using a Fabry-Perot interferometer. Photomultipler tubes operated in the photon counting mode allow high frequency sampling of the circular interference pattern to provide time-resolved flow property measurements. Mean and rms velocity and temperature fluctuation measurements in both an electrically-heated jet facility with a 10-mm diameter nozzle and also in a hydrogen-combustor heated jet facility with a 50.8-mm diameter nozzle at NASA Glenn Research Center are presented.

  12. Velocity Measurements of Turbulent Wake Flow Over a Circular Cylinder

    NASA Astrophysics Data System (ADS)

    Shih, Chang-Lung; Chen, Wei-Cheng; Chang, Keh-Chin; Wang, Muh-Rong

    2016-06-01

    There are two general concerns in the velocity measurements of turbulence. One is the temporal characteristics which governs the turbulent mixing process. Turbulence is rotational and is characterized by high levels of fluctuating vorticity. In order to obtain the information of vorticity dynamics, the spatial characteristics is the other concern. These varying needs can be satisfied by using a variety of diagnostic techniques such as invasive physical probes and non-invasive optical instruments. Probe techniques for the turbulent measurements are inherently simple and less expensive than optical methods. However, the presence of a physical probe may alter the flow field, and velocity measurements usually become questionable when probing recirculation zones. The non-invasive optical methods are mostly made of the foreign particles (or seeding) instead of the fluid flow and are, thus, of indirect method. The difference between the velocities of fluid and foreign particles is always an issue to be discussed particularly in the measurements of complicated turbulent flows. Velocity measurements of the turbulent wake flow over a circular cylinder will be made by using two invasive instruments, namely, a cross-type hot-wire anemometry (HWA) and a split-fiber hot-film anemometry (HFA), and a non-invasive optical instrument, namely, particle image velocimetry (PIV) in this study. Comparison results show that all three employed diagnostic techniques yield similar measurements in the mean velocity while somewhat deviated results in the root-mean-squared velocity, particularly for the PIV measurements. It is demonstrated that HFA possesses more capability than HWA in the flow measurements of wake flow. Wake width is determined in terms of either the flatness factor or shear-induced vorticity. It is demonstrated that flow data obtained with the three employed diagnostic techniques are capable of yielding accurate determination of wake width.

  13. Accuracy of dilution techniques for access flow measurement during hemodialysis.

    PubMed

    Krivitski, N M; MacGibbon, D; Gleed, R D; Dobson, A

    1998-03-01

    Access flow is now widely measured by creating artificial recirculation with the dialysis lines reversed and using dilution methods that sense either ultrasound velocity, electrical impedance, optical, or thermal changes. This study identifies and quantifies factors that influence the accuracy of access flow measurements and recommends ways to reduce these errors. Two major sources of access flow measurement error are identified, arising firstly from the second pass of the indicator by recirculation through the cardiopulmonary system (cardiopulmonary recirculation, CPR), and secondly from changes in venous line blood flow (Qb) and vascular access flow induced by the pressure of venous bolus injections. These errors are considered from theory, by direct measurement of access flow in a sheep model, and by analysis of clinical data. Two extremes for the venous introduction of indicator can be considered in access flow measurements, a slow infusion, which perturbs neither the venous line flow nor access flow but increases the error attributable to the second pass of the indicator by recirculation through cardiopulmonary system, or rapid injection, which eases separation of the second pass of the indicator signal but generates changes in the venous flow and access flow. If CPR is not eliminated, the area added to that of the first pass of indicator ranges up to 40%. Good time resolution could permit the separation of the areas generated by the first and second passage of the indicator. In sheep experiments, injections of 5 or 10 mL into a venous port close to the vascular access caused Qb to change by 20% to 40%. Both the animal experiments and analysis of raw data collected during routine clinical dialysis showed that moving the injection site sufficiently far from the patient, before or into the venous bubble trap, reduced the increase in Qb to only approximately 5% during the critical time when the concentration curve is changing for most tubing brands (Baxter, Belco

  14. Noninvasive measurement of cerebrospinal fluid flow using an ultrasonic transit time flow sensor: a preliminary study.

    PubMed

    Pennell, Thomas; Yi, Juneyoung L; Kaufman, Bruce A; Krishnamurthy, Satish

    2016-03-01

    OBJECT Mechanical failure-which is the primary cause of CSF shunt malfunction-is not readily diagnosed, and the specific reasons for mechanical failure are not easily discerned. Prior attempts to measure CSF flow noninvasively have lacked the ability to either quantitatively or qualitatively obtain data. To address these needs, this preliminary study evaluates an ultrasonic transit time flow sensor in pediatric and adult patients with external ventricular drains (EVDs). One goal was to confirm the stated accuracy of the sensor in a clinical setting. A second goal was to observe the sensor's capability to record real-time continuous CSF flow. The final goal was to observe recordings during instances of flow blockage or lack of flow in order to determine the sensor's ability to identify these changes. METHODS A total of 5 pediatric and 11 adult patients who had received EVDs for the treatment of hydrocephalus were studied in a hospital setting. The primary EVD was connected to a secondary study EVD that contained a fluid-filled pressure transducer and an in-line transit time flow sensor. Comparisons were made between the weight of the drainage bag and the flow measured via the sensor in order to confirm its accuracy. Data from the pressure transducer and the flow sensor were recorded continuously at 100 Hz for a period of 24 hours by a data acquisition system, while the hourly CSF flow into the drip chamber was recorded manually. Changes in the patient's neurological status and their time points were noted. RESULTS The flow sensor demonstrated a proven accuracy of ± 15% or ± 2 ml/hr. The flow sensor allowed real-time continuous flow waveform data recordings. Dynamic analysis of CSF flow waveforms allowed the calculation of the pressure-volume index. Lastly, the sensor was able to diagnose a blocked catheter and distinguish between the blockage and lack of flow. CONCLUSIONS The Transonic flow sensor accurately measures CSF output within ± 15% or ± 2 ml

  15. Model experiments on measuring flow in microvessels using tracers.

    PubMed

    Federspiel, W J; Malai, K

    1993-11-01

    Most techniques for measuring plasma or red cell flow velocity within microvessels rely on determining the transit time of a tracer to transverse the distance between two monitoring sites within a vessel. In principle, proper transit time determinations require flow-weighted sampling of the tracer at monitoring sites. In practical application of the tracer technique, however, trace sampling at monitoring sites is not flow-weighted but is area-weighted, and hence elapsed transient time can only be estimated from tracer data. We previously showed theoretically (Microvasc. Res. 40, 394-411, 1990) that the flow velocity determined under these conditions can differ appreciably from the actual mean flow velocity of the carrier fluid within the microvessel. Nevertheless, trace mean flow velocity does approach that of the fluid when tracer velocity is measured past a finite distance from the microvessel entrance. In this study, we examined the tracer measurement of flow experimentally using a physical model. We perfused single glass microvessels and simple fabricated microvessel networks with distilled water at physiological flow rates. Mean tracer velocity (Vd) was determined at several axial locations within the microvessels using injected Evans blue dye. At each location Vd was determined in a manner consistent with usual application of the tracer flow measurement technique. Actual mean flow velocity (Va) was determined from the measured effluent flow rates discharged from each microvessel. Our experimental results confirm the existence of an appreciable velocity measurement error (VME) associated with the tracer technique. The VME behavior was consistent with our original theoretical analysis. Vd was significantly smaller than Va within a finite length of vessel near the entrance, but approached and became equal to Va past this length. Furthermore, even under conditions where the VME was negligible at the end of a parent microvessel, a new and appreciable VME arose

  16. POD analysis of PIV measurements in complex near wake flows

    NASA Astrophysics Data System (ADS)

    Al-Garni, A. M.; Bernal, L. P.

    2003-11-01

    Proper Orthogonal Decomposition analysis of PIV measurements is used to study the turbulent flow structure in the near wake of bluff bodies. Several body geometries are considered including two-dimensional cylindrical shapes, rounded-nose bluff bodies and typical road vehicle geometries. The main goal of the study is to determine the more energetic POD modes and associated unsteady flow, and the underlying near wake dynamics. We briefly review the results of POD analysis of PIV measurements in two-dimensional geometries. We show that in more complicated flow fields, different POD modes capture the turbulent energy in different regions of the wake. For example, in the flow over a pickup truck, modes 1 and 2 capture the turbulent structure in the underbody shear layer, while mode 4 captures the turbulent structure of the flow over the bed. This result has significant implications for flow control applications. The POD methodology is used to identify generic unsteady flow structures in the near wake. The dominant modes are an oscillation of the length of the recirculation region behind the body (breathing mode) and a lateral oscillation of the wake (flapping mode). In some cases a vortex shedding mode reminiscent of the Karman-Roshko structure in circular cylinders is also observed. Efforts to determine the dynamics of the experimentally measured POD modes are discussed.

  17. Volumetric Flow Measurement Using an Implantable CMUT Array.

    PubMed

    Mengli Wang; Jingkuang Chen

    2011-06-01

    This paper describes volumetric-flow velocity measurement using an implantable capacitive micromachined ultrasonic transducer (CMUT) array. The array is comprised of multiple-concentric CMUT rings for ultrasound transmission and an outmost annular CMUT array for ultrasound reception. Microelectromechanical-system (MEMS) fabrication technology allows reception CMUT on this flowmeter to be implemented with a different membrane thickness and gap height than that of transmission CMUTs, optimizing the performance of these two different kinds of devices. The silicon substrate of this 2-mm-diameter CMUT ring array was bulk micromachined to approximately 80 to 100 μm thick, minimizing tissue disruption. The blood-flow velocity was detected using pulse ultrasound Doppler by comparing the demodulated echo ultrasound with the incident ultrasound. The demodulated ultrasound signal was sampled by a pulse delayed in time domain from the transmitted burst, which corresponds to detecting the signal at a specific distance. The flow tube/vessel diameter was detected through the time-flight delay difference from near and far wall reflections, which was measured from the ultrasound pulse echo. The angle between the ultrasound beam and the flow was found by using the cross-correlation from consecutive ultrasound echoes. Artificial blood flowing through three different polymer tubes was experimented with, while keeping the same volumetric flow rate. The discrepancy in flow measurement results between this CMUT meter and a calibrated laser Doppler flowmeter is less than 5%. PMID:23851472

  18. A thermal stack structure for measurement of fluid flow

    NASA Astrophysics Data System (ADS)

    Zhao, Hao; Mitchell, S. J. N.; Campbell, D. H.; Gamble, Harold S.

    2003-03-01

    A stacked thermal structure for fluid flow sensing has been designed, fabricated, and tested. A double-layer polysilicon process was employed in the fabrication. Flow measurement is based on the transfer of heat from a temperature sensor element to the moving fluid. The undoped or lightly doped polysilicon temperature sensor is located on top of a heavily doped polysilicon heater element. A dielectric layer between the heater and the sensor elements provides both thermal coupling and electrical isolation. In comparison to a hot-wire flow sensor, the heating and sensing functions are separated, allowing the electrical characteristics of each to be optimized. Undoped polysilicon has a large temperature coefficient of resistance (TCR) up to 7 %/K and is thus a preferred material for the sensor. However, heavily doped polysilicon is preferred for the heater due to its lower resistance. The stacked flow sensor structure offers a high thermal sensitivity making it especially suitable for medical applications where the working temperatures are restricted. Flow rates of various fluids can be measured over a wide range. The fabricated flow sensors were used to measure the flow rate of water in the range μl - ml/min and gas (Helium) in the range 10 - 100ml/min.

  19. Phase-locked measurements of gas-liquid horizontal flows

    NASA Astrophysics Data System (ADS)

    Zadrazil, Ivan; Matar, Omar; Markides, Christos

    2014-11-01

    A flow of gas and liquid in a horizontal pipe can be described in terms of various flow regimes, e.g. wavy stratified, annular or slug flow. These flow regimes appear at characteristic gas and liquid Reynolds numbers and feature unique wave phenomena. Wavy stratified flow is populated by low amplitude waves whereas annular flow contains high amplitude and long lived waves, so called disturbance waves, that play a key role in a liquid entrainment into the gas phase (droplets). In a slug flow regime, liquid-continuous regions travel at high speeds through a pipe separated by regions of stratified flow. We use a refractive index matched dynamic shadowgraphy technique using a high-speed camera mounted on a moving robotic linear rail to track the formation and development of features characteristic for the aforementioned flow regimes. We show that the wave dynamics become progressively more complex with increasing liquid and gas Reynolds numbers. Based on the shadowgraphy measurements we present, over a range of conditions: (i) phenomenological observations of the formation, and (ii) statistical data on the downstream velocity distribution of different classes of waves. EPSRC Programme Grant, MEMPHIS, EP/K0039761/1.

  20. Precision electron flow measurements in a disk transmission line.

    SciTech Connect

    Clark, Waylon T.; Pelock, Michael D.; Martin, Jeremy Paul; Jackson, Daniel Peter Jr.; Savage, Mark Edward; Stoltzfus, Brian Scott; Mendel, Clifford Will, Jr.; Pointon, Timothy David

    2008-01-01

    An analytic model for electron flow in a system driving a fixed inductive load is described and evaluated with particle in cell simulations. The simple model allows determining the impedance profile for a magnetically insulated transmission line given the minimum gap desired, and the lumped inductance inside the transition to the minimum gap. The model allows specifying the relative electron flow along the power flow direction, including cases where the fractional electron flow decreases in the power flow direction. The electrons are able to return to the cathode because they gain energy from the temporally rising magnetic field. The simulations were done with small cell size to reduce numerical heating. An experiment to compare electron flow to the simulations was done. The measured electron flow is {approx}33% of the value from the simulations. The discrepancy is assumed to be due to a reversed electric field at the cathode because of the inductive load and falling electron drift velocity in the power flow direction. The simulations constrain the cathode electric field to zero, which gives the highest possible electron flow.

  1. Two parametric flow measurement in gas-liquid two-phase flow

    NASA Astrophysics Data System (ADS)

    Chen, Z.; Chen, C.; Xu, Y.; Zhao, Z.

    The importance and current development of two parametric measurement during two-phase flow are briefly reviewed in this paper. Gas-liquid two-phase two parametric metering experiments were conducted by using an oval gear meter and a sharp edged orifice mounted in series in a horizontal pipe. Compressed air and water were used as gas and liquid phases respectively. The correlations, which can be used to predict the total flow rate and volumetric quality of two-phase flow or volumetric flow rate of each phase, have also been proposed in this paper. Comparison of the calculated values of flow rate of each phase from the correlations with the test data showed that the root mean square fractional deviation for gas flow rate is 2.9 percent and for liquid flow rate 4.4 percent. The method proposed in this paper can be used to measure the gas and liquid flow rate in two-phase flow region without having to separate the phases.

  2. Effects of equipment and technique on peak flow measurements

    PubMed Central

    Bongers, Thomas; O'Driscoll, B Ronan

    2006-01-01

    Background Different lung function equipment and different respiratory manoeuvres may produce different Peak Expiratory Flow (PEF) results. Although the PEF is the most common lung function test, there have been few studies of these effects and no previous study has evaluated both factors in a single group of patients. Methods We studied 36 subjects (PEF range 80–570 l/min). All patients recorded PEF measurements using a short rapid expiration following maximal inspiration (PEF technique) or a forced maximal expiration to residual volume (FVC technique). Measurements were made using a Wright's peak flow meter, a turbine spirometer and a Fleisch pneumotachograph spirometer. Results The mean PEF was 8.7% higher when the PEF technique was used (compared with FVC technique, p < 0.0001). The mean PEF recorded with the turbine spirometer was 5.5% lower than the Wright meter reading. The Fleisch spirometer result was 19.5% lower than the Wright reading. However, adjustment of the Wrights measurements from the traditional Wright's scale to the new EU Peak Flow scale produced results that were only 7.2% higher than the Fleisch pneumotachograph measurements. Conclusion Peak flow measurements are affected by the instruction given and by the device and Peak Flow scale used. Patient management decisions should not be based on PEF measurement made on different instruments. PMID:16787543

  3. Induction and measurement of minute flow rates through nanopipes

    NASA Astrophysics Data System (ADS)

    Sinha, Shashank; Pia Rossi, Maria; Mattia, D.; Gogotsi, Yury; Bau, Haim H.

    2007-01-01

    A simple technique to simultaneously induce fluid flow through an individual nanopipe and measure the flow rate and the pressure difference across the pipe is described. Two liquid drops of different sizes are positioned at the two ends of the nanopipe. Due to the higher capillary pressure of the smaller drop, flow is driven from the smaller drop to the bigger drop. The instantaneous pressures of the two drops are estimated from the drops' shapes and sizes. The flow rate is estimated by monitoring the sizes of the drops as functions of time with a microscope and a video camera. A theory that correlates the drops' sizes and the flow rate is derived. Measurements are carried out with an ionic salt and glycerin to estimate the effective tube radius of the nanopipes with diameters ranging from 200 to 300nm. The tubes' diameters are independently measured with a scanning electron microscope. The method is also verified by tracking the motion of fluorescent particles through the nanopipe. The paper provides a simple technique for studying extremely low flow rates in nanofluidic systems. When working with low-evaporation fluids such as ionic salts, the measurements can be carried out with an electron microscope.

  4. Examining School Security Measures as Moderators of the Association between Homophobic Victimization and School Avoidance

    ERIC Educational Resources Information Center

    Fisher, Benjamin W.; Tanner-Smith, Emily E.

    2016-01-01

    Homophobic victimization is a pervasive problem in U.S. schools that leads to negative outcomes for students. Those who experience homophobic victimization are at greater risk for avoiding particular spaces in school because they feel unsafe or afraid. Visible school security measures (e.g., security guards, metal detectors, and cameras) offer…

  5. Examining School Security Measures as Moderators of the Association between Homophobic Victimization and School Avoidance

    ERIC Educational Resources Information Center

    Fisher, Benjamin W.; Tanner-Smith, Emily E.

    2015-01-01

    Homophobic victimization is a pervasive problem in U.S. schools that leads to negative outcomes for students. Those who experience homophobic victimization are at greater risk for avoiding particular spaces in school because they feel unsafe or afraid. Visible school security measures (e.g., security guards, metal detectors, and cameras) offer…

  6. Field measurement of basal forces generated by erosive debris flows

    USGS Publications Warehouse

    McCoy, S.W.; Tucker, G.E.; Kean, J.W.; Coe, J.A.

    2013-01-01

    It has been proposed that debris flows cut bedrock valleys in steeplands worldwide, but field measurements needed to constrain mechanistic models of this process remain sparse due to the difficulty of instrumenting natural flows. Here we present and analyze measurements made using an automated sensor network, erosion bolts, and a 15.24 cm by 15.24 cm force plate installed in the bedrock channel floor of a steep catchment. These measurements allow us to quantify the distribution of basal forces from natural debris‒flow events that incised bedrock. Over the 4 year monitoring period, 11 debris‒flow events scoured the bedrock channel floor. No clear water flows were observed. Measurements of erosion bolts at the beginning and end of the study indicated that the bedrock channel floor was lowered by 36 to 64 mm. The basal force during these erosive debris‒flow events had a large‒magnitude (up to 21 kN, which was approximately 50 times larger than the concurrent time‒averaged mean force), high‒frequency (greater than 1 Hz) fluctuating component. We interpret these fluctuations as flow particles impacting the bed. The resulting variability in force magnitude increased linearly with the time‒averaged mean basal force. Probability density functions of basal normal forces were consistent with a generalized Pareto distribution, rather than the exponential distribution that is commonly found in experimental and simulated monodispersed granular flows and which has a lower probability of large forces. When the bed sediment thickness covering the force plate was greater than ~ 20 times the median bed sediment grain size, no significant fluctuations about the time‒averaged mean force were measured, indicating that a thin layer of sediment (~ 5 cm in the monitored cases) can effectively shield the subjacent bed from erosive impacts. Coarse‒grained granular surges and water‒rich, intersurge flow had very similar basal force distributions despite

  7. A Structured-Grid Quality Measure for Simulated Hypersonic Flows

    NASA Technical Reports Server (NTRS)

    Alter, Stephen J.

    2004-01-01

    A structured-grid quality measure is proposed, combining three traditional measurements: intersection angles, stretching, and curvature. Quality assesses whether the grid generated provides the best possible tradeoffs in grid stretching and skewness that enable accurate flow predictions, whereas the grid density is assumed to be a constraint imposed by the available computational resources and the desired resolution of the flow field. The usefulness of this quality measure is assessed by comparing heat transfer predictions from grid convergence studies for grids of varying quality in the range of [0.6-0.8] on an 8'half-angle sphere-cone, at laminar, perfect gas, Mach 10 wind tunnel conditions.

  8. An Innovative Flow-Measuring Device: Thermocouple Boundary Layer Rake

    NASA Technical Reports Server (NTRS)

    Hwang, Danny P.; Fralick, Gustave C.; Martin, Lisa C.; Wrbanek, John D.; Blaha, Charles A.

    2001-01-01

    An innovative flow-measuring device, a thermocouple boundary layer rake, was developed. The sensor detects the flow by using a thin-film thermocouple (TC) array to measure the temperature difference across a heater strip. The heater and TC arrays are microfabricated on a constant-thickness quartz strut with low heat conductivity. The device can measure the velocity profile well into the boundary layer, about 65 gm from the surface, which is almost four times closer to the surface than has been possible with the previously used total pressure tube.

  9. Measuring fluid flow and heat output in seafloor hydrothermal environments

    NASA Astrophysics Data System (ADS)

    Germanovich, Leonid N.; Hurt, Robert S.; Smith, Joshua E.; Genc, Gence; Lowell, Robert P.

    2015-12-01

    We review techniques for measuring fluid flow and advective heat output from seafloor hydrothermal systems and describe new anemometer and turbine flowmeter devices we have designed, built, calibrated, and tested. These devices allow measuring fluid velocity at high- and low-temperature focused and diffuse discharge sites at oceanic spreading centers. The devices perform at ocean floor depths and black smoker temperatures and can be used to measure flow rates ranging over 2 orders of magnitude. Flow velocity is determined from the rotation rate of the rotor blades or paddle assembly. These devices have an open bearing design that eliminates clogging by particles or chemical precipitates as the fluid passes by the rotors. The devices are compact and lightweight enough for deployment from either an occupied or remotely operated submersible. The measured flow rates can be used in conjunction with vent temperature or geochemical measurements to obtain heat outputs or geochemical fluxes from both vent chimneys and diffuse flow regions. The devices have been tested on 30 Alvin dives on the Juan de Fuca Ridge and 3 Jason dives on the East Pacific Rise (EPR). We measured an anomalously low entrainment coefficient (0.064) and report 104 new measurements over a wide range of discharge temperatures (5°-363°C), velocities (2-199 cm/s), and depths (1517-2511 m). These include the first advective heat output measurements at the High Rise vent field and the first direct fluid flow measurement at Middle Valley. Our data suggest that black smoker heat output at the Main Endeavour vent field may have declined since 1994 and that after the 2005-2006 eruption, the high-temperature advective flow at the EPR 9°50'N field may have become more channelized, predominately discharging through the Bio 9 structure. We also report 16 measurements on 10 Alvin dives and 2 Jason dives with flow meters that predate devices described in this work and were used in the process of their development

  10. Constraints on Lava Flow Emplacement Derived From Precision Topographic Measurements

    NASA Astrophysics Data System (ADS)

    Zimbelman, J. R.; Bjonnes, E. E.

    2005-12-01

    Precision topography obtained with a Differential Global Positioning System (DGPS) was used to derive constraints on the physical properties of two lava flows on the Big Island of Hawaii. We used a Trimble 4800 DGPS to collect positional information across the lava flows with < 2 cm horizontal and < 4 cm vertical precision (but field tests show that points are usually repeatable to < 1 cm both horizontally and vertically). The DGPS data were overlaid on georeferenced aerial and satellite imaging data, allowing us to correlate the measured topographic points to field notes and photographs, as well as to the local setting evident in the vertical images. We combined field and imaging data for the eastern lobe of the 1907 basalt flow from the southwestern rift zone of Mauna Loa volcano, east of the Ocean View Estates subdivision, and for portions of a grass-covered Pleistocene benmoreite flow near Mana on the western flank of Mauna Kea volcano. Measured physical dimensions of the Hawaiian lava flows obtained from the DGPS data were then used to calculate the yield strength, average effusion rate, and effective viscosity of the lavas using published relationships derived from diverse theories of fluid flow. Yield strengths obtained from three different expressions ranged from 5800 to 56000 Pa for the Mauna Loa basalt flow and from 13000 to 28000 Pa for the Mauna Kea benmoreite flow. Total flow length could not be determined for the Mauna Kea flow, but the entire surface portion of the 1907 flow is well exposed; this allowed us to calculate an average effusion rate of 29 m/s and effective viscosities ranging from 17000 to 280000 Pa-s for this flow, broadly consistent with values published for the 1984 basalt flow from the eastern rift zone of Mauna Loa. These results improve our confidence in being able to derive similar constraints on the likely emplacement conditions of lava flows on other planets, such as the enormous lava flows commonly found on the martian, venusian

  11. 40 CFR 92.107 - Fuel flow measurement.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    .... (iii) If the mass of fuel consumed is measured electronically (load cell, load beam, etc.), the error... 40 Protection of Environment 20 2014-07-01 2013-07-01 true Fuel flow measurement. 92.107 Section...) CONTROL OF AIR POLLUTION FROM LOCOMOTIVES AND LOCOMOTIVE ENGINES Test Procedures § 92.107 Fuel...

  12. Difficult lessons learned in measuring flow on small watersheds

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Submersible pressure transducers integrated with data loggers have become relatively common measuring devices in flow or well water level measurements. However, drift, linearity, hysteresis and other problems can lead to erroneous data. Researchers at the USDA-ARS in Watkinsville, GA, carried out ov...

  13. A technique for measuring hypersonic flow velocity profiles

    NASA Technical Reports Server (NTRS)

    Gartrell, L. R.

    1973-01-01

    A technique for measuring hypersonic flow velocity profiles is described. This technique utilizes an arc-discharge-electron-beam system to produce a luminous disturbance in the flow. The time of flight of this disturbance was measured. Experimental tests were conducted in the Langley pilot model expansion tube. The measured velocities were of the order of 6000 m/sec over a free-stream density range from 0.000196 to 0.00186 kg/cu m. The fractional error in the velocity measurements was less than 5 percent. Long arc discharge columns (0.356 m) were generated under hypersonic flow conditions in the expansion-tube modified to operate as an expansion tunnel.

  14. Detailed flow measurements in a centrifugal compressor vaneless diffuser

    SciTech Connect

    Pinarbasi, A. . Dept. of Mechanical Engineering); Johnson, M.W. . Dept. of Mechanical Engineering)

    1994-07-01

    Hot-wire anemometer measurements have been made in the vaneless diffuser of a 1-m-dia low-speed backswept centrifugal compressor using a phase lock loop technique. Radial, tangential, and axial velocity measurements have been made on eight measurement planes through the diffuser. The flow field at the diffuser entry clearly shows the impeller jet-wake flow pattern and the blade wakes. The passage wake is located on the shroud side of the diffuser and mixes out slowly as the flow moves through the diffuser. The blade wakes, on the other hand, distort and mix out rapidly in the diffuser. Contours of turbulent kinetic energy are also presented on each of the measurement stations, from which the regions of turbulent mixing can be deduced.

  15. Measurement of normal portal venous blood flow by Doppler ultrasound.

    PubMed

    Brown, H S; Halliwell, M; Qamar, M; Read, A E; Evans, J M; Wells, P N

    1989-04-01

    The volume flow rate of blood in the portal vein was measured using a duplex ultrasound system. The many errors inherent in the duplex method were assessed with particular reference to the portal vein and appropriate correction factors were obtained by in vitro calibration. The effect of posture on flow was investigated by examining 45 healthy volunteers in three different positions; standing, supine and tilted head down at 20 degrees from the horizontal. The mean volume blood flow in the supine position was 864 (188)ml/min (mean 1SD). When standing, the mean volume blood flow was significantly reduced by 26% to 662 (169)ml/min. There was, however, no significant difference between flow when supine and when tilted head down at 20 degrees from the horizontal. PMID:2653973

  16. Volumetric velocity measurements on flows through heart valves

    NASA Astrophysics Data System (ADS)

    Troolin, Daniel; Amatya, Devesh; Longmire, Ellen

    2009-11-01

    Volumetric velocity fields inside two types of artificial heart valves were obtained experimentally through the use of volumetric 3-component velocimetry (V3V). Index matching was used to mitigate the effects of optical distortions due to interfaces between the fluid and curved walls. The steady flow downstream of a mechanical valve was measured and the results matched well with previously obtained 2D PIV results, such as those of Shipkowitz et al. (2002). Measurements upstream and downstream of a deformable silicone valve in a pulsatile flow were obtained and reveal significant three-dimensional features of the flow. Plots and movies will be shown, and a detailed discussion of the flow and various experimental considerations will be included. Reference: Shipkowitz, T, Ambrus J, Kurk J, Wickramasinghe K (2002) Evaluation technique for bileaflet mechanical valves. J. Heart Valve Disease. 11(2) pp. 275-282.

  17. Tailoring Inlet Flow to Enable High Accuracy Compressor Performance Measurements

    NASA Astrophysics Data System (ADS)

    Brossman, John R.; Smith, Natalie R.; Talalayev, Anton; Key, Nicole L.

    2011-12-01

    To accomplish the research goals of capturing the effects of blade row interactions on compressor performance, small changes in performance must be measurable. This also requires axi-symmetric flow so that measuring one passage accurately captures the phenomena occurring in all passages. Thus, uniform inlet flow is a necessity. The original front-driven compressor had non-uniform temperature at the inlet. Additional challenges in controlling shaft speed to within tight tolerances were associated with the use of a viscous fluid coupling. Thus, a new electric motor, with variable frequency drive speed control was implemented. To address the issues with the inlet flow, the compressor is now driven from the rear resulting in improved inlet flow uniformity. This paper presents the design choices of the new layout in addition to the preliminary performance data of the compressor and an uncertainty analysis.

  18. Direct Measurement of the Flow Field around Swimming Microorganisms

    NASA Astrophysics Data System (ADS)

    Drescher, Knut; Goldstein, Raymond E.; Michel, Nicolas; Polin, Marco; Tuval, Idan

    2010-10-01

    Swimming microorganisms create flows that influence their mutual interactions and modify the rheology of their suspensions. While extensively studied theoretically, these flows have not been measured in detail around any freely-swimming microorganism. We report such measurements for the microphytes Volvox carteri and Chlamydomonas reinhardtii. The minute (˜0.3%) density excess of V. carteri over water leads to a strongly dominant Stokeslet contribution, with the widely-assumed stresslet flow only a correction to the subleading source dipole term. This implies that suspensions of V. carteri have features similar to suspensions of sedimenting particles. The flow in the region around C. reinhardtii where significant hydrodynamic interaction is likely to occur differs qualitatively from a puller stresslet, and can be described by a simple three-Stokeslet model.

  19. Direct measurement of the flow field around swimming microorganisms

    NASA Astrophysics Data System (ADS)

    Polin, Marco; Drescher, Knut; Goldstein, Raymond E.; Michel, Nicolas; Tuval, Idan

    2010-11-01

    Swimming microorganisms create flows that influence their mutual interactions and modify the rheology of their suspensions. While extensively studied theoretically, these flows have not been measured in detail around any freely-swimming microorganism. We report such measurements for the microphytes Volvox carteri and Chlamydomonas reinhardtii. The minute (˜0.3%) density excess of V. carteri over water leads to a strongly dominant Stokeslet contribution, with the widely-assumed stresslet flow only a correction to the subleading source dipole term. This implies that suspensions of V. carteri have features similar to suspensions of sedimenting particles. The flow in the region around C. reinhardtii where significant hydrodynamic interaction is likely to occur differs qualitatively from a "puller" stresslet, and can be described by a simple three-Stokeslet model.

  20. Device for Measuring Low Flow Speed in a Duct

    NASA Technical Reports Server (NTRS)

    Quinn, Frank; Magee, Kevin

    2009-01-01

    A multiple-throat venturi system has been invented for measuring laminar flow of air or other gas at low speed (1 to 30 cm/s) in a duct while preserving the laminar nature of the flow and keeping the velocity profile across the duct as nearly flat as possible. While means for measuring flows at higher speeds are well established, heretofore, there have been no reliable means for making consistent, accurate measurements in this speed range. In the original application for which this system was invented, the duct leads into the test section of a low-speed wind tunnel wherein uniform, low-speed, laminar flow is required for scientific experiments. The system could also be used to monitor a slow flow of gas in an industrial process like chemical vapor deposition. In the original application, the multiple- throat venturi system is mounted at the inlet end of the duct having a rectangular cross section of 19 by 14 cm, just upstream of an assembly of inlet screens and flow straighteners that help to suppress undesired flow fluctuations (see Figure 1). The basic venturi measurement principle is well established: One measures the difference in pressure between (1) a point just outside the inlet, where the pressure is highest and the kinetic energy lowest; and (2) the narrowest part (the throat) of the venturi passage, where the kinetic energy is highest and the pressure is lowest. Then by use of Bernoulli s equation for the relationship between pressure and kinetic energy, the volumetric flow speed in the duct can be calculated from the pressure difference and the inlet and throat widths. The design of this system represents a compromise among length, pressure recovery, uniformity of flow, and complexity of assembly. Traditionally, venturis are used to measure faster flows in narrower cross sections, with longer upstream and downstream passages to maintain accuracy. The dimensions of the passages of the present venturi system are sized to provide a readily measurable

  1. Experimental Investigation of Effects of Moderate Sideslip on the Flow Fields near a 45 Degree Swept-wing-fuselage Combination at Low Speed

    NASA Technical Reports Server (NTRS)

    Alford, William J , Jr; King, Thomas J , Jr

    1957-01-01

    The flow fields near a 45 degree swept-wing-fuselage combination at moderate angles of sideslip (plus-or-minus 8 degrees), as determined experimentally at low speed, are presented as variations with chordwise distance for various spanwise and vertical locations and angles of attack. The results indicated that for positions close to the fuselage (on and near the plane of symmetry) changes in the angle of sideslip caused large changes in the flow-field characteristics and particularly in the local angles of sideslip, which in some cases were nearly double the static angle of sideslip. In general, the effects of changing the angle of sideslip on the flow-field characteristics for all of the outboard underwing locations were qualitatively similar, although conditions at the more inboard and outboard locations were somewhat more severe for lifting conditions than at the one-half semispan location. The chordwise gradients in the flow parameters for the underwing locations were more severe than for the fuselage locations although the effect of changing the angle of sideslip was less severe, in that the incremental changes in the local angles of sideslip were approximately equal to the static angle of sideslip. Flow conditions near the wing tip were found to be critically dependent on vertical location, with the largest sideslip-induced variations occurring at the nearest vertical locations. The results also indicated that for the outboard underwing locations the wing was the predominant factor in disturbing the field of flow for the conditions investigated.

  2. Prediction of flow profiles in arteries from local measurements.

    NASA Technical Reports Server (NTRS)

    Ling, S. C.; Atabek, H. B.

    1971-01-01

    This paper develops an approximate numerical method for calculating flow profiles in arteries. The theory takes into account the nonlinear terms of the Navier-Stokes equations as well as the large deformations of the arterial wall. The method, assuming axially symmetric flow, determines velocity distribution and wall shear at a given location from the locally measured values of the pressure, pressure gradient, and pressure-radius relation. The computed results agree well with the corresponding experimental data.

  3. Dynamic Pressure Probes Developed for Supersonic Flow-Field Measurements

    NASA Technical Reports Server (NTRS)

    Porro, A. Robert

    2001-01-01

    A series of dynamic flow-field pressure probes were developed for use in large-scale supersonic wind tunnels at the NASA Glenn Research Center. These flow-field probes include pitot and static pressure probes that can capture fast-acting flow-field pressure transients occurring on a millisecond timescale. The pitot and static probes can be used to determine local Mach number time histories during a transient event. The flow-field pressure probe contains four major components: 1) Static pressure aerodynamic tip; 2) Pressure-sensing cartridge assembly; 3) Pitot pressure aerodynamic tip; 4) Mounting stem. This modular design allows for a variety of probe tips to be used for a specific application. Here, the focus is on flow-field pressure measurements in supersonic flows, so we developed a cone-cylinder static pressure tip and a pitot pressure tip. Alternatively, probe tips optimized for subsonic and transonic flows could be used with this design. The pressure-sensing cartridge assembly allows the simultaneous measurement of steady-state and transient pressure which allows continuous calibration of the dynamic pressure transducer.

  4. Micro PIV measurement of slip flow on a hydrogel surface

    NASA Astrophysics Data System (ADS)

    Kikuchi, K.; Mochizuki, O.

    2014-06-01

    Slip flow on a hydrogel surface was investigated in order to clarify the effect of drag reduction on the aqueous surface of living things. Thin-film flow along the hydrogel surface was measured by using a micro PIV (particle image velocimetry) system for comparison with theoretical velocity distribution which satisfied the non-slip condition on a solid surface. The slip flow on the hydrogel was found to be related to the degree of swelling and molecular weight of the hydrogel materials. This shows the possibility of a reduction in wall shear stress as a result of the decrease in the velocity gradient near a wall surface.

  5. Intrusive and nonintrusive measurements of flow properties in arc jets

    NASA Technical Reports Server (NTRS)

    Scott, Carl D.

    1991-01-01

    While numerous diagnostic techniques are available for determining the flow properties of arc jets, these have to be used complementarily in order to cover all the requisite information. Although intrusive techniques disturb the flow, they yield much information. The determination of total enthalpy remains a major challenge, and accurate heat-flux measurements entail knowledge of atom recombination and chemical energy recombination coefficients. Such state-specific methods as the spectroscopic and laser techniques are useful in understanding the chemistry and nonequilibrium reaction and excitation rates of the flow.

  6. Measurement of VOC reactivities using a photochemical flow reactor

    SciTech Connect

    Hurley, M.D.; Chang, T.Y.; Japar, S.M.; Wallington, T.J.

    1998-07-01

    A commercial ambient air monitoring instrument, the Airtrak 2000, has been modified for use as a photochemical flow reactor and used to measure the absolute and incremental reactivity of 18 single test VOCs and the incremental reactivity of six multicomponent VOC mixtures. A flow technique is a useful supplement to traditional static chamber experiments. The static chamber technique involves periodic sampling of an irradiated mixture in a photochemical chamber. Under these conditions, the irradiated mixture is always in transition. Using a flow system, a steady-state condition is established within the flow reactor that is representative, in this case, of the early stages of the smog forming process in the atmosphere. The measurement technique also allows changes in the background chamber reactivity to be monitored and taken into account. The incremental reactivity of 13 of the 18 test compounds measured is compared with previously reported results from a static chamber experiment, and the two data sets are generally in good agreement. The additivity of reactivity was tested by measuring the incremental reactivity of six multicomponent mixtures, the components being compounds measured individually in this study. The measured reactivity of a mixture was compared to that calculated from the sum of the measured reactivity of the mixture`s individual components. The results show that reactivity is additive for the concentration range studied.

  7. Intravital video microscopy measurements of retinal blood flow in mice.

    PubMed

    Harris, Norman R; Watts, Megan N; Leskova, Wendy

    2013-01-01

    Alterations in retinal blood flow can contribute to, or be a consequence of, ocular disease and visual dysfunction. Therefore, quantitation of altered perfusion can aid research into the mechanisms of retinal pathologies. Intravital video microscopy of fluorescent tracers can be used to measure vascular diameters and bloodstream velocities of the retinal vasculature, specifically the arterioles branching from the central retinal artery and of the venules leading into the central retinal vein. Blood flow rates can be calculated from the diameters and velocities, with the summation of arteriolar flow, and separately venular flow, providing values of total retinal blood flow. This paper and associated video describe the methods for applying this technique to mice, which includes 1) the preparation of the eye for intravital microscopy of the anesthetized animal, 2) the intravenous infusion of fluorescent microspheres to measure bloodstream velocity, 3) the intravenous infusion of a high molecular weight fluorescent dextran, to aid the microscopic visualization of the retinal microvasculature, 4) the use of a digital microscope camera to obtain videos of the perfused retina, and 5) the use of image processing software to analyze the video. The same techniques can be used for measuring retinal blood flow rates in rats. PMID:24429840

  8. System and method measuring fluid flow in a conduit

    DOEpatents

    Ortiz, M.G.; Kidd, T.G.

    1999-05-18

    A system is described for measuring fluid mass flow in a conduit in which there exists a pressure differential in the fluid between at least two spaced-apart locations in the conduit. The system includes a first pressure transducer disposed in the side of the conduit at a first location for measuring pressure of fluid at that location, a second or more pressure transducers disposed in the side of the conduit at a second location, for making multiple measurements of pressure of fluid in the conduit at that location, and a computer for computing the average pressure of the multiple measurements at the second location and for computing flow rate of fluid in the conduit from the pressure measurement by the first pressure transducer and from the average pressure calculation of the multiple measurements. 3 figs.

  9. System and method measuring fluid flow in a conduit

    DOEpatents

    Ortiz, Marcos German; Kidd, Terrel G.

    1999-01-01

    A system for measuring fluid mass flow in a conduit in which there exists a pressure differential in the fluid between at least two spaced-apart locations in the conduit. The system includes a first pressure transducer disposed in the side of the conduit at a first location for measuring pressure of fluid at that location, a second or more pressure transducers disposed in the side of the conduit at a second location, for making multiple measurements of pressure of fluid in the conduit at that location, and a computer for computing the average pressure of the multiple measurements at the second location and for computing flow rate of fluid in the conduit from the pressure measurement by the first pressure transducer and from the average pressure calculation of the multiple measurements.

  10. Development of a hybrid k-epsilon turbulence model for swirling recirculating flows under moderate to strong swirl intensities

    NASA Astrophysics Data System (ADS)

    Chang, Keh-Chin; Chen, Ching-Shun

    1993-03-01

    A hybrid k-epsilon turbulence model, based on the concept that the modification of anisotropic effects should not be made in the flow regions inherent to small streamline curvatures, has been developed and examined with the swirling recirculating flows, with the swirl levels ranging from 0.6 to 1.23 in an abrupt pipe expansion. A fairly satisfactory agreement of model predictions with the experimental data shows that this hybrid k-epsilon model can perform better simulation of swirling recirculating flows as compared to the standard k-epsilon model and the modified k-epsilon model proposed by Abujelala and Lilley (1984).

  11. Inductive plethysmography potential as a surrogate for ventilatory measurements during rest and moderate physical exercise

    PubMed Central

    Cabiddu, Ramona; Pantoni, Camila B. F.; Mendes, Renata G.; Trimer, Renata; Catai, Aparecida M.; Borghi-Silva, Audrey

    2016-01-01

    Background: Portable respiratory inductive plethysmography (RIP) systems have been validated for ventilatory assessment during resting conditions and during incremental treadmill exercise. However, in clinical settings and during field-based exercise, intensity is usually constant and submaximal. A demonstration of the ability of RIP to detect respiratory measurements accurately during constant intensity conditions would promote and validate the routine use of portable RIP devices as an alternative to ergospirometry (ES), the current gold standard technique for ventilatory measures. Objective: To investigate the agreement between respiratory variables recorded by a portable RIP device and by ES during rest and constant intensity exercise. Method: Tidal volume (VT), respiratory rate (RR) and minute ventilation (VE) were concurrently acquired by portable RIP and ES in seven healthy male volunteers during standing rest position and constant intensity treadmill exercise. Results: Significant agreement was found between RIP and ES acquisitions during the standing rest position and constant intensity treadmill exercise for RR and during the standing rest position for VE. Conclusion: Our results suggest that portable RIP devices might represent a suitable alternative to ES during rest and during constant submaximal exercise. PMID:26982454

  12. Laboratory and field trials of Coriolis mass flow metering for three-phase flow measurement

    NASA Astrophysics Data System (ADS)

    Zhou, Feibiao; Henry, Manus; Tombs, Michael

    2014-04-01

    A new three-phase flow metering technology is discussed in this paper, which combines Coriolis mass flow and water cut readings and without applying any phase separation [1]. The system has undergone formal laboratory trials at TUV NEL (National Engineering Laboratory), UK and at VNIIR (National Flow Laboratory), Kazan, Russia; a number of field trials have taken place in Russia. Laboratory trial results from the TUV NEL will be described in detail. For the 50mm (2") metering system, the total liquid flow rate ranged from 2.4 kg/s up to 11 kg/s, the water cut ranged from 0% to 100%, and the gas volume fraction (GVF) from 0 to 50%. In a formally observed trial, 75 test points were taken at a temperature of approximately 40 °C and with a skid inlet pressure of approximately 350 kPa. Over 95% of the test results fell within the desired specification, defined as follows: the total (oil + water) liquid mass flow error should fall within ± 2.5%, and the gas mass flow error within ± 5.0%. The oil mass flow error limit is ± 6.0% for water cuts less than 70%, while for water cuts between 70% and 95% the oil mass flow error limit is ± 15.0%. These results demonstrate the potential for using Coriolis mass flow metering combined with water cut metering for three-phase (oil/water/gas) measurement.

  13. Flow field measurements in a 90 degree turning duct

    NASA Technical Reports Server (NTRS)

    Crawford, Roger A.; Peters, Carroll E.

    1985-01-01

    The objective of this investigation is the experimental evaluation of the influence of inlet turbulence intensity on secondary flow development in a turning duct. The existing 25.4 cm square turning duct (90) facility is being utilized to investigate of bulk turbulence levels on secondary flow development. The large scale duct flow facility allows detailed mean velocity and turbulence quantities to be measured at several streamwise planes in the curved duct. Non-intrusive laser velocimetry is being used to measure the mean and fluctuating components of velocity in all three orthogonal directions. To assure that the turbulence measurements are unbiased by particle lag and other effects, comparison hot wire data will be taken to validate the laser velocimetry system calibration.

  14. The GUINEVERE experiment: First PNS measurements in a lead moderated sub-critical fast core

    SciTech Connect

    Thyebault, H. E.; Billebaud, A.; Chabod, S.; Lecolley, F. R.; Lecouey, J. L.; Lehaut, G.; Marie, N.; Ban, G.

    2012-07-01

    The GUINEVERE (Generation of Uninterrupted Intense Neutrons at the lead Venus Reactor) experimental program is dedicated to the study of Accelerator Driven System reactivity monitoring. It was partly carried out within the EUROTRANS integrated project (EURATOM FP6). GUINEVERE consists in coupling the fast core of the VENUS-F reactor (SCK-CEN, Mol (Belgium)), composed of enriched uranium and solid lead, with a T(d,n) neutron source provided by the GENEPI-3C deuteron accelerator. This neutron source can be operated in several modes: pulsed mode, continuous mode and also continuous mode with short beam interruptions (the so called 'beam trips'). In the past, the key questions of the reactivity control and monitoring in a subcritical system were studied in the MUSE experiments (1998-2004). These experiments highlighted the difficulty to determine precisely the reactivity with a single technique. This led to investigate a new strategy which is based on the combination of the relative reactivity monitoring via the core power to beam current relationship with absolute reactivity cross-checks during programmed beam interruptions. Consequently, to determine the reactivity, several dynamical techniques of reactivity determination have to be compared. In addition, their accuracy for absolute reactivity determination must be evaluated using a reference reactivity determination technique (from a critical state: rod drop and MSM measurements). The first sub-critical configuration which was studied was around k{sub eff} = 0.96 (SCI). Pulsed Neutron Source experiments (PNS) were carried out. The neutron population decrease was measured using fission chambers in different locations inside the core and the reflector. Neutron population time decrease was analyzed using fitting techniques and the Area Method Results obtained for the SCI reactivity will be shown, discussed and compared to the reference value given by the MSM method. (authors)

  15. Measurements of Turbulent Flow Field in Separate Flow Nozzles with Enhanced Mixing Devices - Test Report

    NASA Technical Reports Server (NTRS)

    Bridges, James

    2002-01-01

    As part of the Advanced Subsonic Technology Program, a series of experiments was conducted at NASA Glenn Research Center on the effect of mixing enhancement devices on the aeroacoustic performance of separate flow nozzles. Initial acoustic evaluations of the devices showed that they reduced jet noise significantly, while creating very little thrust loss. The explanation for the improvement required that turbulence measurements, namely single point mean and RMS statistics and two-point spatial correlations, be made to determine the change in the turbulence caused by the mixing enhancement devices that lead to the noise reduction. These measurements were made in the summer of 2000 in a test program called Separate Nozzle Flow Test 2000 (SFNT2K) supported by the Aeropropulsion Research Program at NASA Glenn Research Center. Given the hot high-speed flows representative of a contemporary bypass ratio 5 turbofan engine, unsteady flow field measurements required the use of an optical measurement method. To achieve the spatial correlations, the Particle Image Velocimetry technique was employed, acquiring high-density velocity maps of the flows from which the required statistics could be derived. This was the first successful use of this technique for such flows, and shows the utility of this technique for future experimental programs. The extensive statistics obtained were likewise unique and give great insight into the turbulence which produces noise and how the turbulence can be modified to reduce jet noise.

  16. Flow Disturbance Measurements in the National Transonic Facility

    NASA Technical Reports Server (NTRS)

    King, Rudolph A.; Andino, Marlyn Y.; Melton, Latunia; Eppink, Jenna; Kegerise, Michael A.

    2013-01-01

    Recent flow measurements have been acquired in the National Transonic Facility to assess the test-section unsteady flow environment. The primary purpose of the test is to determine the feasibility of the facility to conduct laminar-flow-control testing and boundary-layer transition-sensitive testing at flight-relevant operating conditions throughout the transonic Mach number range. The facility can operate in two modes, warm and cryogenic test conditions for testing full and semispan-scaled models. Data were acquired for Mach and unit Reynolds numbers ranging from 0.2 less than or equal to M less than or equal to 0.95 and 3.3 × 10(exp 6) less than Re/m less than 220×10(exp 6) collectively at air and cryogenic conditions. Measurements were made in the test section using a survey rake that was populated with 19 probes. Roll polar data at selected conditions were obtained to look at the uniformity of the flow disturbance field in the test section. Data acquired included mean total temperatures, mean and fluctuating static/total pressures, and mean and fluctuating hot-wire measurements. This paper focuses primarily on the unsteady pressure and hot-wire results. Based on the current measurements and previous data, an assessment was made that the facility may be a suitable facility for ground-based demonstrations of laminar-flow technologies at flight-relevant conditions in the cryogenic mode.

  17. Mass flow rate measurement in abrasive jets using acoustic emission

    NASA Astrophysics Data System (ADS)

    Ivantsiv, V.; Spelt, J. K.; Papini, M.

    2009-09-01

    The repeatability of abrasive jet machining operations is presently limited by fluctuations in the mass flow rate due to powder compaction, stratification and humidity effects. It was found that the abrasive mass flow rate for a typical abrasive jet micromachining setup could be determined by using data from the acoustic emission of the abrasive jet impacting a flat plate. Two methods for extracting the mass flow rate from the acoustic emission were developed and compared. In the first method, the number of particle impacts per unit time was determined by a direct count of peaks in the acoustic emission signal. The second method utilizes the power spectrum density of the acoustic emission in a specific frequency range. Both measures were found to correlate strongly with the mass flow rate measured by weighing samples of blasted powder for controlled time periods. It was found that the peak count method permits measurement of the average frequency of the impacts and the mass flow rate, but can only be applied to flow rates in which the impact frequency is approximately one order of magnitude less than the frequency of the target plate ringing. The power spectrum density method of signal processing is applicable to relatively fine powders and to flow rates at which the average impact frequency is of the same order of magnitude as that of the ringing due to the impact. The acoustic emission technique can be used to monitor particle flow variations over a wide range of time periods and provides a straightforward and accurate means of process control.

  18. Sensors for Using Times of Flight to Measure Flow Velocities

    NASA Technical Reports Server (NTRS)

    Fralick, Gutave; Wrbanek, John D.; Hwang, Danny; Turso, James

    2006-01-01

    Thin-film sensors for measuring flow velocities in terms of times of flight are undergoing development. These sensors are very small and can be mounted flush with surfaces of airfoils, ducts, and other objects along which one might need to measure flows. Alternatively or in addition, these sensors can be mounted on small struts protruding from such surfaces for acquiring velocity measurements at various distances from the surfaces for the purpose of obtaining boundary-layer flow-velocity profiles. These sensors are related to, but not the same as, hot-wire anemometers. Each sensor includes a thin-film, electrically conductive loop, along which an electric current is made to flow to heat the loop to a temperature above that of the surrounding fluid. Instantaneous voltage fluctuations in segments of the loop are measured by means of electrical taps placed at intervals along the loop. These voltage fluctuations are caused by local fluctuations in electrical resistance that are, in turn, caused by local temperature fluctuations that are, in turn, caused by fluctuations in flow-induced cooling and, hence, in flow velocity. The differential voltage as a function of time, measured at each pair of taps, is subjected to cross-correlation processing with the corresponding quantities measured at other pairs of taps at different locations on the loop. The cross-correlations yield the times taken by elements of fluid to travel between the pairs of taps. Then the component of velocity along the line between any two pairs of taps is calculated simply as the distance between the pairs of taps divided by the travel time. Unlike in the case of hot-wire anemometers, there is no need to obtain calibration data on voltage fluctuations versus velocity fluctuations because, at least in principle, the correlation times are independent of the calibration data.

  19. Doppler Global Velocimetry Measurements for Supersonic Flow Fields

    NASA Technical Reports Server (NTRS)

    Meyers, James F.

    2005-01-01

    The application of Doppler Global Velocimetry (DGV) to high-speed flows has its origins in the original development of the technology by Komine et al (1991). Komine used a small shop-air driven nozzle to generate a 200 m/s flow. This flow velocity was chosen since it produced a fairly large Doppler shift in the scattered light, resulting in a significant transmission loss as the light passed through the Iodine vapor. This proof-of-concept investigation showed that the technology was capable of measuring flow velocity within a measurement plane defined by a single-frequency laser light sheet. The effort also proved that velocity measurements could be made without resolving individual seed particles as required by other techniques such as Fringe- Type Laser Velocimetry and Particle Image Velocimetry. The promise of making planar velocity measurements with the possibility of using 0.1-micron condensation particles for seeding, Dibble et al (1989), resulted in the investigation of supersonic jet flow fields, Elliott et al (1993) and Smith and Northam (1995) - Mach 2.0 and 1.9 respectively. Meyers (1993) conducted a wind tunnel investigation above an inclined flat plate at Mach 2.5 and above a delta wing at Mach 2.8 and 4.6. Although these measurements were crude from an accuracy viewpoint, they did prove that the technology could be used to study supersonic flows using condensation as the scattering medium. Since then several research groups have studied the technology and developed solutions and methodologies to overcome most of the measurement accuracy limitations:

  20. Flow cytometric measurement of total DNA and incorporated halodeoxyuridine

    DOEpatents

    Dolbeare, Frank A.; Gray, Joe W.

    1986-01-01

    A method for the simultaneous flow cytometric measurement of the total DNA content and the level of DNA synthesis in normal and malignant cells is disclosed. The sensitivity of the method allows a study of cell cycle traverse rates for large scale cell populations as well as single cell measurements. A DNA stain such as propidium iodide is used as the probe for the measurement of total DNA content and a monoclonal antibody reactive with a DNA precursor such as bromodeoxyuridine (BrdU) is used as a probe for the measurement of BrdU uptake by the cells as a measure of DNA synthesis.

  1. A new approach to highly resolved measurements of turbulent flow

    NASA Astrophysics Data System (ADS)

    Puczylowski, J.; Hölling, A.; Peinke, J.; Bhiladvala, R.; Hölling, M.

    2015-05-01

    In this paper we present the design and principle of a new anemometer, namely the 2d-Laser Cantilever Anemometer (2d-LCA), which has been developed for highly resolved flow speed measurements of two components (2d) under laboratory conditions. We will explain the working principle and demonstrate the sensor’s performance by means of comparison measurements of wake turbulence with a commercial X-wire. In the past we have shown that the 2d-LCA is capable of being applied in liquid and particle-laden domains, but we also believe that other challenging areas of operation such as near-wall flows can become accessible.

  2. Density measurements in an expanding flow using holographic interferometry

    NASA Technical Reports Server (NTRS)

    Sharma, Surendra P.; Ruffin, Stephen M.; Meyer, Scott A.; Gillespie, Walter D.; Yates, Leslie A.

    1992-01-01

    A nonequilibrium expansion of nitrogen through a 2-dimensional nozzle of a reflected shock tunnel is investigated with laser holography, time resolved pressure measurements and emission spectroscopy to characterize the flow field for vibrational relaxation measurements. A 2D computation is used to simulate the nozzle flow field. Synthetic holograms are generated using the computed density profiles and are compared with the experimental holograms. Also, using a quasi 1-D approximation, populations for each vibrational level are computed by (1) solving the master equations and (2) using the Landau-Teller formulation. Computational accuracy of both models is assessed against the experimental data.

  3. On the measurement of lateral velocity derivatives in turbulent flows

    NASA Technical Reports Server (NTRS)

    Antonia, R. A.; Zhu, Y.; Kim, J.

    1993-01-01

    Direct numerical simulation data for the lateral velocity derivative delta(u)/delta(y) at the centerline of a fully developed turbulent channel flow provide reasonable support for Wyngaard's analysis of the error involved in measuring this quantity using parallel hot wires. Numerical data in the wall region of the channel flow also provide a useful indication of how to select the separation between the wires. Justification for this choice is obtained by comparing several measured statistics of delta(u)/delta(y) with the corresponding numerical data.

  4. Quantitative Full-Scale Wind Turbine Flow Measurements

    NASA Astrophysics Data System (ADS)

    Kinzel, Matthias; Mulligan, Quinn; Dabiri, John

    2011-11-01

    To analyze the interaction between vertical axis wind turbines (VAWT) in detail it is important to gain a deeper understanding of their flow field. Quantitative in situ measurements pose a great challenge because of the large spatial dimensions, high flow velocities and remote locations of the VAWT. The aim of this work is to perform Particle Image Velocitmetry (PIV) in a horizontal cross section of a VAWT. The major difficulty is the choice of adequate seeding particles and illumination method for the large field of view, which is necessary. The flow velocities on the other hand require a high speed camera and the whole setup has to be powered self-sufficiently. However, PIV yields a two dimensional two component velocity field together with the out of plane component of vorticity and is therefore a considerable advantage over the single point measurements which are available today. The presentation will deal with different methods for seeding the flow. The properties of these flow tracers will be discussed and their ability to follow the flow reliably evaluated. Preliminary PIV results of the wind velocities at the test site will be shown. The financial support of the Moore Foundation is gratefully acknowledged.

  5. Microprobes For Blood Flow Measurements In Tissue And Small Vessels

    NASA Astrophysics Data System (ADS)

    Oberg, P. A.; Salerud, E. G.

    1988-04-01

    Laser Doppler flowmetry is a method for the continuous and non-invasive recording of tissue blood flow. The method has already proved to be advantageous in a number of clinical as well as theoretical medical disciplines. In dermatology, plastic- and gastrointestinal surgery laser Doppler measurements have substantially contributed to increase knowledge of microvascular perfusion. In experimental medicine, the method has been used in the study of a great variety of microvascular problems. Spontaneous rhythmical variations, spatial and temporal fluctuations in human skin blood flow are mentioned as examples of problem areas in which new knowledge has been generated. The method has facilitated further investigations of the nature of spongeous bone blood flow, testis and kidney cortex blood flow. Recently we have showed that a variant of the laser Doppler method principle, using a single optical fiber, can be advantageous in deep tissue measurements. With this method laser light is transmitted bidirectionally in a single fiber. The tissue trauma which affects blood flow can be minimized by introducing small diameter fibers (0.1-0.5 mm). A special set-up utilizing the same basic principle has been used for the recording of blood flow in small vessels.

  6. Fan Noise Source Diagnostic Test: LDV Measured Flow Field Results

    NASA Technical Reports Server (NTRS)

    Podboy, Gary C.; Krupar, Martin J.; Hughes, Christopher E.; Woodward, Richard P.

    2003-01-01

    Results are presented of an experiment conducted to investigate potential sources of noise in the flow developed by two 22-in. diameter turbofan models. The R4 and M5 rotors that were tested were designed to operate at nominal take-off speeds of 12,657 and 14,064 RPMC, respectively. Both fans were tested with a common set of swept stators installed downstream of the rotors. Detailed measurements of the flows generated by the two were made using a laser Doppler velocimeter system. The wake flows generated by the two rotors are illustrated through a series of contour plots. These show that the two wake flows are quite different, especially in the tip region. These data are used to explain some of the differences in the rotor/stator interaction noise generated by the two fan stages. In addition to these wake data, measurements were also made in the R4 rotor blade passages. These results illustrate the tip flow development within the blade passages, its migration downstream, and (at high rotor speeds) its merging with the blade wake of the adjacent (following) blade. Data also depict the variation of this tip flow with tip clearance. Data obtained within the rotor blade passages at high rotational speeds illustrate the variation of the mean shock position across the different blade passages.

  7. Two-Phase Mass Flow Measurement Using Noise Analysis

    SciTech Connect

    Evans, Robert Pugmire; Keller, Joseph George; Stephens, A. G.; Blotter, J.

    1999-05-01

    The purpose of this work is to develop a low cost, non-intrusive, mass flow measurement sensor for two-phase flow conditions in geothermal applications. The emphasis of the work to date has been on a device that will monitor two-phase flow in the above-ground piping systems. The flashing brines have the potential for excessive scaling and corrosion of exposed surfaces, which can reduce the effectiveness of any measurement device. A major objective in the work has been the development of an instrument that is less susceptible to the scaling and corrosion effects. The focus of the project efforts has been on transducer noise analysis, a technology initiated at the INEEL. A transducer sensing a process condition will have, in addition to its usual signal, various noise components superimposed upon the primary signal that can be related to flow. Investigators have proposed that this technique be applied to steam and liquid water flow mixtures where the signal from an accelerometer mounted on an external pipe surface is evaluated to determine flow rate.

  8. Flow measurements in a centrifugal diffusor test device

    NASA Astrophysics Data System (ADS)

    Vitting, T.

    1985-06-01

    This work sought to verify concepts used in the design of a large scale, low speed, radial cascade wind tunnel which was to be used to investigate flow phenomena in and the performance of vaned radial diffusors. A major contributor to centrifugal compressor efficiency is the performance of the vaned diffusor which closely follows the impeller of the compressor. The purpose of this diffusor is to efficiently convert most of the kinetic energy of the transonic flow entering the vane into pressure. The need for an experimental facility which could simulate adequately, at low cost and in a controlled way, the environment of the centrifugal compressor motivated the development of the Centrifugal Diffusor Test Device (CDTD). It was expected that the generation of a three dimensional flow would provide improved empirical data on annular cascade performance. This measurement program surveyed the axial and circumferential uniformity of the flow at the inlet of a transonic wedge-type blading mounted in the device. Evaluation of the results showed the flow uniformity to be unsatisfactory. Leakage and other small perturbations in the flow field in the swirl generator are believed to be amplified by the basic flow configuration of the device.

  9. Flow field measurements in the cell culture unit

    NASA Technical Reports Server (NTRS)

    Walker, Stephen; Wilder, Mike; Dimanlig, Arsenio; Jagger, Justin; Searby, Nancy

    2002-01-01

    The cell culture unit (CCU) is being designed to support cell growth for long-duration life science experiments on the International Space Station (ISS). The CCU is a perfused loop system that provides a fluid environment for controlled cell growth experiments within cell specimen chambers (CSCs), and is intended to accommodate diverse cell specimen types. Many of the functional requirements depend on the fluid flow field within the CSC (e.g., feeding and gas management). A design goal of the CCU is to match, within experimental limits, all environmental conditions, other than the effects of gravity on the cells, whether the hardware is in microgravity ( micro g), normal Earth gravity, or up to 2g on the ISS centrifuge. In order to achieve this goal, two steps are being taken. The first step is to characterize the environmental conditions of current 1g cell biology experiments being performed in laboratories using ground-based hardware. The second step is to ensure that the design of the CCU allows the fluid flow conditions found in 1g to be replicated from microgravity up to 2g. The techniques that are being used to take these steps include flow visualization, particle image velocimetry (PIV), and computational fluid dynamics (CFD). Flow visualization using the injection of dye has been used to gain a global perspective of the characteristics of the CSC flow field. To characterize laboratory cell culture conditions, PIV is being used to determine the flow field parameters of cell suspension cultures grown in Erlenmeyer flasks on orbital shakers. These measured parameters will be compared to PIV measurements in the CSCs to ensure that the flow field that cells encounter in CSCs is within the bounds determined for typical laboratory experiments. Using CFD, a detailed simulation is being developed to predict the flow field within the CSC for a wide variety of flow conditions, including microgravity environments. Results from all these measurements and analyses of the

  10. Heat flow measurements on the southeast coast of Australia

    USGS Publications Warehouse

    Hyndman, R.D.; Jaeger, J.C.; Sass, J.H.

    1969-01-01

    Three boreholes have been drilled for the Australian National University near the southeast coast of New South Wales, Australia. The heat flows found are 1.1, 1.0, and 1.3 ??cal/cm2sec. The errors resulting from the proximity of the sea and a lake, surface temperature change, conductivity structure and water flow have been examined. The radioactive heat production in some of the intrusive rocks of the area have also been measured. The heat flows are much lower than the values of about 2.0 found elsewhere in south eastern Australia. The lower values appear to be part of a distinct heat flow province in eastern Australia. ?? 1969.

  11. Improvements on Digital Inline Holographic PIV for Turbulent Flow Measurement

    NASA Astrophysics Data System (ADS)

    Hong, Jiarong; Toloui, Mostafa; Mallery, Kevin

    2015-11-01

    Among all the 3D PIV techniques used in wall-bounded turbulent flow measurements, digital inline holographic (DIH) PIV provides the highest spatial resolution for near-wall flow diagnostics with low-cost, simple and compact optical set-ups. Despite these advantages, DIH-PIV suffers from major limitations including poor longitudinal resolution, human intervention (i.e. requirement for manually determined tuning parameters during tracer field reconstruction and extraction), limited tracer concentration, and expensive computations. These limitations prevent this technique from being widely implemented for high resolution 3D flow measurements. In this study, we present our work on improving holographic particle extraction algorithm with the goal of overcoming some of abovementioned limitations. Our new DIH-PIV processing method has been successfully implemented on multiple experimental cases ranging from 3D flow measurement within a micro-channel to imaging near-wall coherent structures in smooth and rough wall turbulent channel flows. This work is supported by the startup package of Jiarong Hong and the MnDrive Fellowship of Mostafa Toloui from University of Minnesota.

  12. Measuring Actin Flow in 3D Cell Protrusions

    PubMed Central

    Chiu, Chi-Li; Digman, Michelle A.; Gratton, Enrico

    2013-01-01

    Actin dynamics is important in determining cell shape, tension, and migration. Methods such as fluorescent speckle microscopy and spatial temporal image correlation spectroscopy have been used to capture high-resolution actin turnover dynamics within cells in two dimensions. However, these methods are not directly applicable in 3D due to lower resolution and poor contrast. Here, we propose to capture actin flow in 3D with high spatial-temporal resolution by combining nanoscale precise imaging by rapid beam oscillation and fluctuation spectroscopy techniques. To measure the actin flow along cell protrusions in cell expressing actin-eGFP cultured in a type I collagen matrix, the laser was orbited around the protrusion and its trajectory was modulated in a clover-shaped pattern perpendicularly to the protrusion. Orbits were also alternated at two positions closely spaced along the protrusion axis. The pair cross-correlation function was applied to the fluorescence fluctuation from these two positions to capture the flow of actin. Measurements done on nonmoving cellular protrusion tips showed no pair-correlation at two orbital positions indicating a lack of flow of F-actin bundles. However, in some protrusions, the pair-correlation approach revealed directional flow of F-actin bundles near the protrusion surface with flow rates in the range of ∼1 μm/min, comparable to results in two dimensions using fluorescent speckle microscopy. Furthermore, we found that the actin flow rate is related to the distance to the protrusion tip. We also observed collagen deformation by concomitantly detecting collagen fibers with reflectance detection during these actin motions. The implementation of the nanoscale precise imaging by rapid beam oscillation method with a cloverleaf-shaped trajectory in conjunction with the pair cross-correlation function method provides a quantitative way of capturing dynamic flows and organization of proteins during cell migration in 3D in conditions of

  13. Emittance Measurements for a Thin Liquid Sheet Flow

    NASA Technical Reports Server (NTRS)

    Englehart, Amy N.; McConley, Marc W.; Chubb, Donald L.

    1996-01-01

    The Liquid Sheet Radiator (LSR) is an external flow radiator that uses a triangular-shaped flowing liquid sheet as the radiating surface. It has potentially much lower mass than solid wall radiators such as pumped loop and heat pipe radiators, along with being nearly immune to micrometeoroid penetration. The LSR has an added advantage of simplicity. Surface tension causes a thin (100-300 microns) liquid sheet to coalesce to a point, causing the sheet flow to have a triangular shape. Such a triangular sheet is desirable since it allows for simple collection of the flow at a single point. A major problem for all external flow radiators is the requirement that the working fluid be of very low (approx. 10(sup -8) torr) vapor pressure to keep evaporative losses low. As a result, working fluids are limited to certain oils (such as used in diffusion pumps) for low temperatures (300-400 K) and liquid metals for higher temperatures. Previous research on the LSR has been directed at understanding the fluid mechanics of thin sheet flows and assessing the stability of such flows, especially with regard to the formation of holes in the sheet. Taylor studied extensively the stability of thin liquid sheets both theoretically and experimentally. He showed that thin sheets in a vacuum are stable. The latest research has been directed at determining the emittance of thin sheet flows. The emittance was calculated from spectral transmittance data for the Dow Corning 705 silicone oil. By experimentally setting up a sheet flow, the emittance was also determined as a function of measurable quantities, most importantly, the temperature drop between the top of the sheet and the temperature at the coalescence point of the sheet. Temperature fluctuations upstream of the liquid sheet were a potential problem in the analysis and were investigated.

  14. Low Reynolds number Couette flow facility for drag measurements.

    PubMed

    Johnson, Tyler J; Lang, Amy W; Wheelus, Jennifer N; Westcott, Matthew

    2010-09-01

    For this study a new low Reynolds number Couette facility was constructed to investigate surface drag. In this facility, mineral oil was used as the working fluid to increase the shear stress across the surface of the experimental models. A mounted conveyor inside a tank creates a flow above which an experimental model of a flat plate was suspended. The experimental plate was attached to linear bearings on a slide system that connects to a force gauge used to measure the drag. Within the gap between the model and moving belt a Couette flow with a linear velocity profile was created. Digital particle image velocimetry was used to confirm the velocity profile. The drag measurements agreed within 5% of the theoretically predicted Couette flow value. PMID:20887004

  15. Sound power flux measurements in strongly exited ducts with flow.

    PubMed

    Holland, Keith R; Davies, Peter O A L; van der Walt, Danie C

    2002-12-01

    This contribution describes new robust procedures for the measurement of sound power flux at appropriate axial positions along a duct with flow, using pairs of flush wall mounted microphones, or pressure transducers. The technology includes the application of selective averaging, order tracking, and optimized sampling rate methods to identify the small fraction of the total fluctuating wave energy that is being propagated along the flow path in a reverberent, or highly reactive duct system. Such measurements can also be used to quantify the local acoustic characteristics that govern the generation, transfer, and propagation of wave energy in the system. Illustrative examples include the determination of the acoustic characteristics of individual silencing elements installed in IC engine intakes and exhausts both on the flow bench and during controlled acceleration or run down on a test bed, where the wave component spectral levels approached 170 dB. PMID:12509008

  16. Measurements of noise produced by flow past lifting surfaces

    NASA Technical Reports Server (NTRS)

    Kendall, J. M.

    1978-01-01

    Wind tunnel studies have been conducted to determine the specific locations of aerodynamic noise production within the flow field about various lifting-surface configurations. The models tested included low aspect ratio shapes intended to represent aircraft flaps, a finite aspect ratio NACA 0012 wing, and a multi-element wing section consisting of a main section, a leading edge flap, and dual trailing edge flaps. Turbulence was induced on the models by surface roughness. Lift and drag were measured for the flap models. Hot-wire anemometry was used for study of the flap-model vortex roll-up. Apparent noise source distributions were measured by use of a directional microphone system, located outside the tunnel, which was scanned about the flow region to be analyzed under computer control. These distributions exhibited a diversity of pattern, suggesting that several flow processes are important to lifting-surface noise production. Speculation concerning these processes is offered.

  17. Direct measurements of flow and deformation of a free reed

    NASA Astrophysics Data System (ADS)

    Buchak, Peter; Bush, John

    2012-02-01

    The free reed, responsible for producing sound in a family of air-driven musical instruments, is an example of a coupled fluid-structure system engineered to vibrate efficiently at a controllable frequency. In Western free reed instruments, a flexible metal plate is clamped at one end above a slot cut into a rigid support plate. This geometry allows a constant driving pressure to produce and sustain large-amplitude vibrations. The mechanism behind this has been discussed by several investigators. However, it has yet to be verified experimentally with direct measurements of the flow speed. We present simultaneous measurements of the reed motion and the flow speed in the downstream jet, which enable characterization of the relationship between the finite-amplitude deformation of the reed and the flow.

  18. Flow cytometry measurements of human chromosome kinetochore labeling

    SciTech Connect

    Fantes, J.A.; Green, D.K.; Malloy, P.; Sumner, A.T.

    1989-03-01

    A method for the preparation and measurement of immunofluorescent human chromosome centromeres in suspension is described using CREST antibodies, which bind to the centromeric region of chromosomes. Fluorescein isothiocyanate (FITC)-conjugated antihuman antibodies provide the fluorescent label. Labeled chromosomes are examined on microscope slides and by flow cytometry. In both cases a dye which binds to DNA is added to provide identification of the chromosome groups. Sera from different CREST patients vary in their ability to bind to chromosome arms in addition to the centromeric region. Flow cytometry and microfluorimetry measurements have shown that with a given CREST serum the differences in kinetochore fluorescence between chromosomes are only minor. Flow cytometry experiments to relate the number of dicentric chromosomes, induced by in vitro radiation of peripheral blood cells to the slightly increased number of chromosomes with above-average kinetochore fluorescence did not produce decisive radiation dosimetry results.

  19. Time-dependent local density measurements in unsteady flows

    NASA Technical Reports Server (NTRS)

    Mckenzie, R. L.; Monson, D. J.; Exberger, R. J.

    1979-01-01

    A laser-induced fluorescence technique for measuring the relative time-dependent density fluctuations in unsteady or turbulent flows is demonstrated. Using a 1.5-W continuous-wave Kr(+) laser, measurements have been obtained in 0.1-mm diameter by 1-mm-long sampling volumes in a Mach 3 flow of N2 seeded with biacetyl vapor. A signal amplitude resolution of 2% was achieved for a detection frequency bandwidth of 10 kHz. The measurement uncertainty was found to be dominated by noise behaving as photon statistical noise. The practical limits of signal-to-noise ratios have been characterized for a wide range of detection frequency bandwidths that encompasses those of interest in supersonic turbulence measurements.

  20. Time-dependent local density measurements in unsteady flows

    NASA Technical Reports Server (NTRS)

    Mckenzie, R. L.; Monson, D. J.; Exberger, R. J.

    1979-01-01

    A laser-induced fluorescence technique for measuring the relative time-dependent density fluctuations in unsteady or turbulent flows is demonstrated. Using a 1.5-W continuous-wave Kr(+) laser, measurements have been obtained in 0.1-mm-diameter by 1-mm-long sampling volumes in a Mach 3 flow of N2 seeded with biacetyl vapor. A signal amplitude resolution of 2% was achieved for a detection frequency bandwidth of 10 kHz. The measurement uncertainty was found to be dominated by noise behaving as photon statistical noise. The practical limits of signal-to-noise ratios have been characterized for a wide range of detection frequency bandwidths that encompasses those of interest in supersonic turbulence measurements.

  1. U.S. Stream Flow Measurement and Data Dissemination Improve

    NASA Astrophysics Data System (ADS)

    Hirsch, Robert M.; Costa, John E.

    2004-05-01

    Stream flow information is essential for many important uses across a broad range of scales, including global water balances, engineering design, flood forecasting, reservoir operations, navigation, water supply, recreation, and environmental management. Growing populations and competing priorities for water, including preservation and restoration of aquatic habitat, are spurring demand for more accurate, timely, and accessible water data. To be most useful, stream flow information must be collected in a standardized manner, with a known accuracy, and for a long and continuous time period. The U.S. Geological Survey (USGS) operates over 7000 stream gauges nationwide, which constitute over 90% of the nation's stream gauges that provide daily stream flow records, and that are accessible to the public. Most stream flow records are not based on direct measurement of river discharge, but are derived from continuous measurements of river elevations or stage. These stage data, recorded to 3-mm accuracy, are then converted into discharge by use of a stage/discharge relation (rating) that is unique for each stream gauging location. Because stream beds and banks are not static, neither is the stage discharge rating. Much of the effort and cost associated with stream gauging lies in establishing and updating this relation. Ten years ago, USGS personnel would visit stream gauging stations 8 to 10 times a year to make direct measurements of river depth, width, and velocity using mechanical instruments: a sounding rod or cable, a tagline, and a current meter. From these data, flow rates were computed. The range of measured flow and concurrent river stages were then used to build the rating curve for each site and to track changes to the rating curve.

  2. STORM-SEWER FLOW MEASUREMENT AND RECORDING SYSTEM.

    USGS Publications Warehouse

    Kilpatrick, Frederick A.; Kaehrle, William R.

    1986-01-01

    A comprehensive study and development of instruments and techniques for measuring all components of flow in a storm-sewer drainage system were undertaken by the U. S. Geological Survey under the sponsorship of FHWA. The study involved laboratory and field calibration and testing of measuring flumes, pipe insert meters, weirs, and electromagnetic velocity meters as well as the development and calibration of pneumatic bubbler and pressure transducer head-measuring systems. Tracer dilution and acoustic-flowmeter measurements were used in field verification tests. A single micrologger was used to record data from all the instruments and also to activate on command the electromagnetic velocity meter and tracer dilution systems.

  3. Nonintrusive Temperature and Velocity Measurements in a Hypersonic Nozzle Flow

    NASA Technical Reports Server (NTRS)

    OByrne, S.; Danehy, P. M.; Houwing, A. F. P.

    2002-01-01

    Distributions of nitric oxide vibrational temperature, rotational temperature and velocity have been measured in the hypersonic freestream at the exit of a conical nozzle, using planar laser-induced fluorescence. Particular attention has been devoted to reducing the major sources of systematic error that can affect fluorescence tempera- ture measurements, including beam attenuation, transition saturation effects, laser mode fluctuations and transition choice. Visualization experiments have been performed to improve the uniformity of the nozzle flow. Comparisons of measured quantities with a simple one-dimensional computation are made, showing good agreement between measurements and theory given the uncertainty of the nozzle reservoir conditions and the vibrational relaxation rate.

  4. Temperature Measurement in Supersonic Flows by Predissociative Transient Thermal Gratings

    NASA Astrophysics Data System (ADS)

    Barker, Peter; Miles, Richard

    1998-11-01

    We present temporally resolved measurements of temperature in a range of supersonic flows by measuring the acoustic decay of laser created transient gratings. This is an extension of the LITA (Laser-Induced Thermal Acoustics) technique. A thermal density grating is created in the flow folloing absorption and thermalization of light from an interference pattern created by the crossed beams of a short-pulsed laser. Rapid thermalization occurs by collisions with energetic 0 photofragments following predissociation of O^2 in air by absorption of 193 nm light. The grating relaxes to local equilibrium by acoustic and diffusive decay. The acoustic decay launches two counter- propagating gratings traveling at the speed-of-sound. The interference of the stationary thermal grating with the two counter-propagating acoustic gratings creates a variation in grating modulation depth with time. The modulation frequency is proportional to the speed-of-sound and is used in our measurements to determine temperature. Bragg diffraction off the grating by a cw probe laser is observed as an oscillatory decay over hundreds of nanoseconds; the modulation frequency is extracted from this signal by Fourier analysis. We present single laser pulse measurements of temperature in a Mach 2.0 and 3.9 nozzle flows, and in weakly ionized flows for which this technique has been developed.

  5. Measurements of flow past a bileaflet mechanical heart valve

    NASA Astrophysics Data System (ADS)

    Haya, Laura; Tavoularis, Stavros

    2013-11-01

    A bileaflet mechanical heart valve has been inserted in an axisymmetric model of the aorta within a mock circulation apparatus with physiological pressure and flow variations. The velocity field behind the valve has been measured with laser Doppler velocimetry and particle image velocimetry. The results closely match those reported by similar studies. A triple jet emanated from the valve's orifices and regions of reverse flow formed in the sinus region. Velocity fluctuations were greatest in the shear layers of the jets. The average r.m.s. streamwise velocity fluctuation over the turbulent period was 0.22 m/s; its maximum value was 0.53 m/s and occurred at the onset of deceleration. Measurements with the valve inserted in an anatomical model of the aorta are planned for the near future. The present and future measurements will be compared to determine the effects of the aorta anatomy on the characteristics of flow through bileaflet valves. In particular, measurements of the viscous and turbulent shear stresses will be analyzed to identify possible locations of blood element damage, and regions of recirculation and stagnation will be identified as locations favourable to thrombus growth. The effects of flows in branching arteries and valve orientation will also be investigated. Supported by NSERC.

  6. DEVELOPMENT OF AN OPTICAL CONVOLUTION VELOCIMETER FOR MEASURING STACK FLOW

    EPA Science Inventory

    A new type of instrument has been developed and tested for the measurement of stack flow velocities. The instrument is optical and generates a shadowgraph pattern of the wake from a small heater. This shadowgraph is projected on a mirror grating of precise dimensions and the refl...

  7. Heat flow calorimeter. [measures output of Ni-Cd batteries

    NASA Technical Reports Server (NTRS)

    Fletcher, J. C.; Johnston, W. V. (Inventor)

    1974-01-01

    Heat flow calorimeter devices are used to measure heat liberated from or absorbed by an object. This device is capable of measuring the thermal output of sealed nickel-cadmium batteries or cells during charge-discharge cycles. An elongated metal heat conducting rod is coupled between the calorimeter vessel and a heat sink, thus providing the only heat exchange path from the calorimeter vessel itself.

  8. Method and apparatus for measuring coupled flow, transport, and reaction processes under liquid unsaturated flow conditions

    DOEpatents

    McGrail, Bernard P.; Martin, Paul F.; Lindenmeier, Clark W.

    1999-01-01

    The present invention is a method and apparatus for measuring coupled flow, transport and reaction processes under liquid unsaturated flow conditions. The method and apparatus of the present invention permit distinguishing individual precipitation events and their effect on dissolution behavior isolated to the specific event. The present invention is especially useful for dynamically measuring hydraulic parameters when a chemical reaction occurs between a particulate material and either liquid or gas (e.g. air) or both, causing precipitation that changes the pore structure of the test material.

  9. Choice of boundary condition for lattice-Boltzmann simulation of moderate-Reynolds-number flow in complex domains

    NASA Astrophysics Data System (ADS)

    Nash, Rupert W.; Carver, Hywel B.; Bernabeu, Miguel O.; Hetherington, James; Groen, Derek; Krüger, Timm; Coveney, Peter V.

    2014-02-01

    Modeling blood flow in larger vessels using lattice-Boltzmann methods comes with a challenging set of constraints: a complex geometry with walls and inlets and outlets at arbitrary orientations with respect to the lattice, intermediate Reynolds (Re) number, and unsteady flow. Simple bounce-back is one of the most commonly used, simplest, and most computationally efficient boundary conditions, but many others have been proposed. We implement three other methods applicable to complex geometries [Guo, Zheng, and Shi, Phys. Fluids 14, 2007 (2002), 10.1063/1.1471914; Bouzidi, Firdaouss, and Lallemand, Phys. Fluids 13, 3452 (2001), 10.1063/1.1399290; Junk and Yang, Phys. Rev. E 72, 066701 (2005), 10.1103/PhysRevE.72.066701] in our open-source application hemelb. We use these to simulate Poiseuille and Womersley flows in a cylindrical pipe with an arbitrary orientation at physiologically relevant Re number (1-300) and Womersley (4-12) numbers and steady flow in a curved pipe at relevant Dean number (100-200) and compare the accuracy to analytical solutions. We find that both the Bouzidi-Firdaouss-Lallemand (BFL) and Guo-Zheng-Shi (GZS) methods give second-order convergence in space while simple bounce-back degrades to first order. The BFL method appears to perform better than GZS in unsteady flows and is significantly less computationally expensive. The Junk-Yang method shows poor stability at larger Re number and so cannot be recommended here. The choice of collision operator (lattice Bhatnagar-Gross-Krook vs multiple relaxation time) and velocity set (D3Q15 vs D3Q19 vs D3Q27) does not significantly affect the accuracy in the problems studied.

  10. Choice of boundary condition for lattice-Boltzmann simulation of moderate-Reynolds-number flow in complex domains.

    PubMed

    Nash, Rupert W; Carver, Hywel B; Bernabeu, Miguel O; Hetherington, James; Groen, Derek; Krüger, Timm; Coveney, Peter V

    2014-02-01

    Modeling blood flow in larger vessels using lattice-Boltzmann methods comes with a challenging set of constraints: a complex geometry with walls and inlets and outlets at arbitrary orientations with respect to the lattice, intermediate Reynolds (Re) number, and unsteady flow. Simple bounce-back is one of the most commonly used, simplest, and most computationally efficient boundary conditions, but many others have been proposed. We implement three other methods applicable to complex geometries [Guo, Zheng, and Shi, Phys. Fluids 14, 2007 (2002); Bouzidi, Firdaouss, and Lallemand, Phys. Fluids 13, 3452 (2001); Junk and Yang, Phys. Rev. E 72, 066701 (2005)] in our open-source application hemelb. We use these to simulate Poiseuille and Womersley flows in a cylindrical pipe with an arbitrary orientation at physiologically relevant Re number (1-300) and Womersley (4-12) numbers and steady flow in a curved pipe at relevant Dean number (100-200) and compare the accuracy to analytical solutions. We find that both the Bouzidi-Firdaouss-Lallemand (BFL) and Guo-Zheng-Shi (GZS) methods give second-order convergence in space while simple bounce-back degrades to first order. The BFL method appears to perform better than GZS in unsteady flows and is significantly less computationally expensive. The Junk-Yang method shows poor stability at larger Re number and so cannot be recommended here. The choice of collision operator (lattice Bhatnagar-Gross-Krook vs multiple relaxation time) and velocity set (D3Q15 vs D3Q19 vs D3Q27) does not significantly affect the accuracy in the problems studied. PMID:25353601

  11. Measurement of flow separation in a human vocal folds model

    NASA Astrophysics Data System (ADS)

    Šidlof, Petr; Doaré, Olivier; Cadot, Olivier; Chaigne, Antoine

    2011-07-01

    The paper provides experimental data on flow separation from a model of the human vocal folds. Data were measured on a four times scaled physical model, where one vocal fold was fixed and the other oscillated due to fluid-structure interaction. The vocal folds were fabricated from silicone rubber and placed on elastic support in the wall of a transparent wind tunnel. A PIV system was used to visualize the flow fields immediately downstream of the glottis and to measure the velocity fields. From the visualizations, the position of the flow separation point was evaluated using a semiautomatic procedure and plotted for different airflow velocities. The separation point position was quantified relative to the orifice width separately for the left and right vocal folds to account for flow asymmetry. The results indicate that the flow separation point remains close to the narrowest cross-section during most of the vocal fold vibration cycle, but moves significantly further downstream shortly prior to and after glottal closure.

  12. Jet-Surface Interaction Test: Flow Measurements Results

    NASA Technical Reports Server (NTRS)

    Brown, Cliff; Wernet, Mark

    2014-01-01

    Modern aircraft design often puts the engine exhaust in close proximity to the airframe surfaces. Aircraft noise prediction tools must continue to develop in order to meet the challenges these aircraft present. The Jet-Surface Interaction Tests have been conducted to provide a comprehensive quality set of experimental data suitable for development and validation of these exhaust noise prediction methods. Flow measurements have been acquired using streamwise and cross-stream particle image velocimetry (PIV) and fluctuating surface pressure data acquired using flush mounted pressure transducers near the surface trailing edge. These data combined with previously reported far-field and phased array noise measurements represent the first step toward the experimental data base. These flow data are particularly applicable to development of noise prediction methods which rely on computational fluid dynamics to uncover the flow physics. A representative sample of the large flow data set acquired is presented here to show how a surface near a jet affects the turbulent kinetic energy in the plume, the spatial relationship between the jet plume and surface needed to generate surface trailing-edge noise, and differences between heated and unheated jet flows with respect to surfaces.

  13. Measurements of Gas Bubble Size Distributions in Flowing Liquid Mercury

    SciTech Connect

    Wendel, Mark W; Riemer, Bernie; Abdou, Ashraf A

    2012-01-01

    ABSTRACT Pressure waves created in liquid mercury pulsed spallation targets have been shown to induce cavitation damage on the target container. One way to mitigate such damage would be to absorb the pressure pulse energy into a dispersed population of small bubbles, however, measuring such a population in mercury is difficult since it is opaque and the mercury is involved in a turbulent flow. Ultrasonic measurements have been attempted on these types of flows, but the flow noise can interfere with the measurement, and the results are unverifiable and often unrealistic. Recently, a flow loop was built and operated at Oak Ridge National Labarotory to assess the capability of various bubbler designs to deliver an adequate population of bubbles to mitigate cavitation damage. The invented diagnostic technique involves flowing the mercury with entrained gas bubbles in a steady state through a horizontal piping section with a glass-window observation port located on the top. The mercury flow is then suddenly stopped and the bubbles are allowed to settle on the glass due to buoyancy. Using a bright-field illumination and a high-speed camera, the arriving bubbles are detected and counted, and then the images can be processed to determine the bubble populations. After using this technique to collect data on each bubbler, bubble size distributions were built for the purpose of quantifying bubbler performance, allowing the selection of the best bubbler options. This paper presents the novel procedure, photographic technique, sample visual results and some example bubble size distributions. The best bubbler options were subsequently used in proton beam irradiation tests performed at the Los Alamos National Laboratory. The cavitation damage results from the irradiated test plates in contact with the mercury are available for correlation with the bubble populations. The most effective mitigating population can now be designed into prototypical geometries for implementation into

  14. Measurement of Flow Phenomena in a VHTR Lower Plenum Model

    SciTech Connect

    Hugh M. McIlroy Jr.; Donald M. McEligot; Robert J. Pink

    2007-06-01

    Mean velocity and turbulence data that measure turbulent flow phenomena in an approximately 1:7 scale model of a region of the lower plenum of a typical prismatic gas-cooled reactor are presented as a follow-up to summaries presented at the 2006 Annual Meeting and the 2006 Winter Meeting. The experiments were designed to develop benchmark databases to support the first Standard Problem endorsed by the Generation IV International Forum to validate the heat transfer and fluid flow software that will be used to study the behavior of the VHTR system.

  15. Two-phase flow measurements with advanced instrumented spool pieces

    SciTech Connect

    Turnage, K.C.

    1980-09-01

    A series of two-phase, air-water and steam-water tests performed with instrumented piping spool pieces is described. The behavior of the three-beam densitometer, turbine meter, and drag flowmeter is discussed in terms of two-phase models. Results from application of some two-phase mass flow models to the recorded spool piece data are shown. Results of the study are used to make recommendations regarding spool piece design, instrument selection, and data reduction methods to obtain more accurate measurements of two-phase flow parameters. 13 refs., 23 figs., 1 tab.

  16. Torque Transient of Magnetically Drive Flow for Viscosity Measurement

    NASA Technical Reports Server (NTRS)

    Ban, Heng; Li, Chao; Su, Ching-Hua; Lin, Bochuan; Scripa, Rosalia N.; Lehoczky, Sandor L.

    2004-01-01

    Viscosity is a good indicator of structural changes for complex liquids, such as semiconductor melts with chain or ring structures. This paper discusses the theoretical and experimental results of the transient torque technique for non-intrusive viscosity measurement. Such a technique is essential for the high temperature viscosity measurement of high pressure and toxic semiconductor melts. In this paper, our previous work on oscillating cup technique was expanded to the transient process of a magnetically driven melt flow in a damped oscillation system. Based on the analytical solution for the fluid flow and cup oscillation, a semi-empirical model was established to extract the fluid viscosity. The analytical and experimental results indicated that such a technique has the advantage of short measurement time and straight forward data analysis procedures

  17. Holocene Flows of the Cima Volcanic Field, Mojave Desert, Part 2: Flow Rheology from Laboratory Measurements

    NASA Astrophysics Data System (ADS)

    Robertson, T.; Whittington, A. G.; Soldati, A.; Sehlke, A.; Beem, J. R.; Gomez, F. G.

    2014-12-01

    Lava flow morphology is often utilized as an indicator of rheological behavior during flow emplacement. Rheological behavior can be characterized by the viscosity and yield strength of lava, which in turn are dependent on physical and chemical properties including crystallinity, vesicularity, and bulk composition. We are studying the rheology of a basaltic lava flow from a monogenetic Holocene cinder cone in the Cima lava field (Mojave Desert, California). The flow is roughly 2.5 km long and up to 700m wide, with a well-developed central channel along much of its length. Samples were collected along seven different traverses across the flow, along with real-time kinematic (RTK) GPS profiles to allow levee heights and slopes to be measured. Surface textures change from pahoehoe ropes near the vent to predominantly jagged `a`a blocks over the majority of the flow, including all levees and the toe. Chemically the lava shows little variation, plotting on the trachybasalt-basanite boundary on the total alkali-silica diagram. Mineralogically the lava is dominated by plagioclase, clinopyroxene and olivine phenocrysts, with abundant flow-aligned plagioclase microcrystals. The total crystal fraction is ~50% near the vent, with higher percentages in the distal portion of the flow. Vesicularity varies between ~10 and more than ~60%. Levees are ~10-15m high with slopes typically ~25-35˚, suggesting a yield strength at final emplacement of ~150,000 Pa. The effective emplacement temperature and yield strength of lava samples will be determined using the parallel-plate technique. We will test the hypothesis that these physical and rheological properties of the lava during final emplacement correlate with spatial patterns in flow morphology, such as average slope and levee width, which have been determined using remote sensing observations (Beem et al. 2014).

  18. New heat flow measurements in Oman in the Arabian plate

    NASA Astrophysics Data System (ADS)

    Rolandone, F.; Lucazeau, F.; Jaupart, C.; Leroy, S.; Bache, F.; Amerjeed, M.; Lally, J.

    2009-04-01

    Precambrian shields are viewed as low heat flow provinces but detailed studies in Canada, South Africa and India shields demonstrate that large heat flow differences exist between them and within a single province, related to differences of crustal structures. Very few heat flow measurements are available on the Arabian shield and its thermal structure is poorly constrained. Heat flow reported for the Arabian Shield and its immediate platform (36-88 mWm-2) is broad. Thermal regime has a control on rheology and on deformation and the Arabian shield is of particular interest because it was affected by geodynamic processes such as the Red Sea and Gulf of Aden riftings starting around 30 Ma ago and the formation of the Dead Sea Transform fault starting at about 20 Ma. In December 2006, a marine heat-flow survey in the Gulf of Aden provided 169 new heat-flow measurements along multi-channel seismic profiles. One of the main results is that the high heat-flow (~120 mWm-2), characteristic of oceanic domains, extends into the deep continental margin and switches abruptly in the proximal margin to a low value (~40 mWm-2) typical of stable Precambrian domain. These low values have been confirmed by estimates derived from oil exploration data in few locations south of Oman. These data indicate a strong contrast of thermal regimes within the continental margin. Recent tomography studies on Arabia in Oman show that the lithosphere is significantly affected within Arabia in the vicinity of the Red Sea and the Gulf of Aden. This pattern is apparently different from the observed heat-flow pattern, which needs to be confirmed and extended into the Arabian platform. The survey we conducted in October 2008 was to evaluate the thermal regime in the onshore domains of Oman. We measured the temperature gradient in 9 water wells in Dhofar south of Oman and in 8 mining wells in northern Oman in the ophiolite belt. The goal is to investigate the thermal structure of the Arabian plate and

  19. Numerical modeling of separated flows at moderate Reynolds numbers appropriate for turbine blades and unmanned aero vehicles

    NASA Astrophysics Data System (ADS)

    Castiglioni, Giacomo

    Flows over airfoils and blades in rotating machinery, for unmanned and micro-aerial vehicles, wind turbines, and propellers consist of a laminar boundary layer near the leading edge that is often followed by a laminar separation bubble and transition to turbulence further downstream. Typical Reynolds averaged Navier-Stokes turbulence models are inadequate for such flows. Direct numerical simulation is the most reliable, but is also the most computationally expensive alternative. This work assesses the capability of immersed boundary methods and large eddy simulations to reduce the computational requirements for such flows and still provide high quality results. Two-dimensional and three-dimensional simulations of a laminar separation bubble on a NACA-0012 airfoil at Rec = 5x104 and at 5° of incidence have been performed with an immersed boundary code and a commercial code using body fitted grids. Several sub-grid scale models have been implemented in both codes and their performance evaluated. For the two-dimensional simulations with the immersed boundary method the results show good agreement with the direct numerical simulation benchmark data for the pressure coefficient Cp and the friction coefficient Cf, but only when using dissipative numerical schemes. There is evidence that this behavior can be attributed to the ability of dissipative schemes to damp numerical noise coming from the immersed boundary. For the three-dimensional simulations the results show a good prediction of the separation point, but an inaccurate prediction of the reattachment point unless full direct numerical simulation resolution is used. The commercial code shows good agreement with the direct numerical simulation benchmark data in both two and three-dimensional simulations, but the presence of significant, unquantified numerical dissipation prevents a conclusive assessment of the actual prediction capabilities of very coarse large eddy simulations with low order schemes in general

  20. Optical Air Flow Measurements for Flight Tests and Flight Testing Optical Air Flow Meters

    NASA Technical Reports Server (NTRS)

    Jentink, Henk W.; Bogue, Rodney K.

    2005-01-01

    Optical air flow measurements can support the testing of aircraft and can be instrumental to in-flight investigations of the atmosphere or atmospheric phenomena. Furthermore, optical air flow meters potentially contribute as avionics systems to flight safety and as air data systems. The qualification of these instruments for the flight environment is where we encounter the systems in flight testing. An overview is presented of different optical air flow measurement techniques applied in flight and what can be achieved with the techniques for flight test purposes is reviewed. All in-flight optical airflow velocity measurements use light scattering. Light is scattered on both air molecules and aerosols entrained in the air. Basic principles of making optical measurements in flight, some basic optical concepts, electronic concepts, optoelectronic interfaces, and some atmospheric processes associated with natural aerosols are reviewed. Safety aspects in applying the technique are shortly addressed. The different applications of the technique are listed and some typical examples are presented. Recently NASA acquired new data on mountain rotors, mountain induced turbulence, with the ACLAIM system. Rotor position was identified using the lidar system and the potentially hazardous air flow profile was monitored by the ACLAIM system.

  1. Finding flows in the one-way measurement model

    SciTech Connect

    Beaudrap, Niel de

    2008-02-15

    The one-way measurement model is a framework for universal quantum computation in which algorithms are partially described by a graph G of entanglement relations on a collection of qubits. A sufficient condition for an algorithm to perform a unitary embedding between two Hilbert spaces is for the graph G, together with input and output I, O vertices I,O is contained in V(G), to have a flow in the sense introduced by Danos and Kashefi [Phys. Rev. A 74, 052310 (2006)]. For the special case of |I|=|O|, using a graph-theoretic characterization, I show that such flows are unique when they exist. This leads to an efficient algorithm for finding flows by a reduction to solved problems in graph theory.

  2. Non-intrusive flow measurements on a reentry vehicle

    NASA Technical Reports Server (NTRS)

    Miles, R. B.; Satavicca, D. A.; Zimmermann, G. M.

    1983-01-01

    This study evaluates the utility of various non-intrusive techniques for the measurement of the flow field on the windward side of the Space Shuttle or a similar re-entry vehicle. Included are linear (Rayleigh, Raman, Mie, Laser Doppler Velocimetry, Resonant Doppler Velocimetry) and nonlinear (Coherent Anti-Stokes Raman, Laser Induced Fluorescence) light scattering, electron beam fluorescence, thermal emission and mass spectroscopy. Flow field properties are taken from a nonequilibrium flow model by Shinn, Moss and Simmonds at NASA Langley. Conclusions are, when possible, based on quantitative scaling of known laboratory results to the conditions projected. Detailed discussion with researchers in the field contributed further to these conclusions and provided valuable insights regarding the experimental feasibility of each of the techniques.

  3. Mass flow measurement of liquid cryogens using the triboelectric effect

    NASA Technical Reports Server (NTRS)

    Dechene, Ronald L.

    1986-01-01

    A cross correlator technique using triboelectric technology has been shown to be a feasible method to measure liquid flow rate for liquid nitrogen and JP4 jet fuel. This technology, invented and pioneered by Auburn International, Inc., is also expected to be suitable for use with all other insulating liquids and cryogens. The technology described is particularly well suited for cryogenic use, since the sensor is non-contacting and non-intrusive, and therefore, causes no additional pressure drop within the flow stream. Further development of the in-line sensor is required to produce a prototypical version for the test purposes under SSME fuel flow conditions. However, with the knowledge gained from this feasibility study, it is very likely that an acceptable sensor design for a full test bed evaluation could be produced.

  4. Interfacial area measurement and transport modeling in air-water two-phase flow

    NASA Astrophysics Data System (ADS)

    Fu, Xinyu

    In two-fluid model, the interfacial area concentration (IAC) is an important parameter that characterizes the interaction of two-phases at the interface. The accuracy of IAC modeling and local measurements largely affects the efficiency of designing and assessing two-phase flow systems. The prediction of the dynamical evolution of IAC is one of the most challenging tasks in research and application. This thesis is focused on developing advanced local measurement techniques to obtain reliable two-phase parameters and implementing efficient theoretical models for IAC source and sink terms in a two-group interfacial area transport equation based on experiments. In this study, an advanced local measurement technique using a four-sensor conductivity probe has been presented for obtaining IAC in air-water flows. It extends the existing conductivity probe method to slug and churn-turbulent flows with a unified probe design and comprehensive signal processing system. Sophisticated algorithm and software have been implemented that is robust in handling most practical conditions with high reliability. Systematic analyses on the issues of probe applications and benchmarks have been performed. The improved four-sensor method has also been applied to flow conditions with significant local recirculation, which was considered the most challenging situation for local measurement in two-phase flow. Using the well-established instrumentation, solid databases for a two-inch air-water loop have been built with sufficient information on the axial development and the radial distribution of the local parameters. Mechanistic models of major fluid particle interaction phenomena involving two bubble groups have been proposed, including the shearing-off of small bubbles from slug/cap bubbles, the wake entrainment of group-1 bubble into group-2 bubble, the wake acceleration and coalescence between group-2 bubbles, and the breakup of group-2 bubbles due to surface instability. Prediction of

  5. Measurements of biologically effective UV doses, total ozone abundances, and cloud effects with multichannel, moderate bandwidth filter instruments

    NASA Astrophysics Data System (ADS)

    Dahlback, Arne

    1996-11-01

    I describe a method to derive biologically effective UV dose rates, total ozone abundances, and cloud optical depths from irradiance measurements with moderate bandwidth filter instruments that have only a few channels in the UV region. These quantities are determined when the measured irradiances are combined with radiative transfer calculations. The method was applied to a four-channel filter instrument with center wavelengths at 305, 320, 340, and 380 nm and bandwidths of 10 nm. I compared the instrument with a high-wavelength-resolution spectroradiometer during a 1-week period in San Diego, California, with variable cloudiness. The relative difference in Commission Internationale de l clairage (CIE)-weighted UV dose rates for solar zenith angle s (SZA s) 80 was 1.4 3.2 . The relative difference for clear sky was 0.6 1.5 for SZA s 80 . The total ozone inferred from the irradiance measurements with the filter instrument is insensitive to clouds. The instrument was compared with a Dobson and a Brewer instrument in Oslo, Norway, 60 N, for more than 1 year. The relative difference in derived ozone abundance for the entire period, including cloudy days, was 0.3 2.9 . The standard deviation was reduced to 1.9 when only clear sky and SZA s 60 were included. By using the total ozone and the cloud optical depth derived from the filter instrument as input to a radiative transfer model, one can compute a complete spectrum from 290 to 400 nm with 1-nm resolution. Such calculated spectra are in good agreement with spectra measured simultaneously with a high-wavelength-resolution spectroradiometer for clear as well as cloudy sky conditions and can be used to determine dose rates for any desired action spectrum. Only one UV-B channel and one UV-A channel are required to compute the spectra.

  6. Interfacial characteristic measurements in horizontal bubbly two-phase flow

    NASA Astrophysics Data System (ADS)

    Wang, Z.; Huang, W. D.; Srinivasmurthy, S.; Kocamustafaogullari, G.

    1990-10-01

    Advances in the study of two-phase flow increasingly require detailed internal structure information upon which theoretical models can be formulated. The void fraction and interfacial area are two fundamental parameters characterizing the internal structure of two-phase flow. However, little information is currently available on these parameters, and it is mostly limited to vertical flow configurations. In view of the above, the internal phase distribution of concurrent, air-water bubbly flow in a 50.3 mm diameter transparent pipeline has been experimentally investigated by using a double-sensor resistivity probe. Liquid and gas volumetric superficial velocities ranged from 3.74 to 5.60 m/s and 0.25 to 1.59 m/s, respectively, and average void fractions ranged from 2.12 to 22.5 percent. The local values of void fractions, interfacial area concentration, mean bubble diameter, bubble interface velocity, bubble chord-length and bubble frequency distributions were measured. The experimental results indicate that the void fraction interfacial area concentration and bubble frequency have local maxima near the upper pipe wall, and the profiles tend to flatten with increasing void fraction. The observed peak void fraction can reach 0.65, the peak interfacial area can go up to 900 approximately 1000 sq m/cu m, and the bubble frequency can reach a value of 2200 per s. These ranges of values have never been reported for vertical bubbly flow. It is found that either decreasing the liquid flow rate or increasing the gas flow would increase the local void fraction, the interfacial area concentration and the bubble frequency.

  7. Capacitance Transducers for Concentration Measurements in Two Component Flow.

    NASA Astrophysics Data System (ADS)

    Matoorianpour, Nasser

    Available from UMI in association with The British Library. This thesis is concerned with the design and development of instrumentation for non-intrusive measurements of component volumetric concentrations on industrial two component flow including gas/liquid and gas/solids systems. The design and optimisation of two amplitude modulated capacitance transducers for "steady state" or slowly varying concentration measurements are described. A new type of capacitance transducer is the symmetrical capacitance bridge which consists of capacitive voltage dividers based on the voltage measuring method. The sensing electrodes of the sensor in this system are driven at two opposite voltages to produce a symmetrical capacitance sensitivity across the sensing region. Optimum transducer parameters, the use of the driven guard technique and minimised input capacitance to the electronics provide maximum sensitivity in this capacitance bridge. The base line stability of the symmetrical capacitance bridge is further improved by applying a Commutating Auto Zero technique to the transducer. The capacitance sensitivity across the sensing volumes of three pairs of concave plate electrode systems, each subtending a different angle has been investigated experimentally. One application of this transducer, considered in this research, is the void fraction determination in air/water two component flow. A second type of high stability capacitance bridge, based on the current measuring method, is the "stray immune" transformer ratio amplifier bridge. Its high pass filter configuration, using an LCR network, provides noise immunity against the charged solids in the applications involving pneumatically conveyed solid materials. A non-intrusive mass flow rate determination system, based on the stray immune transformer ratio amplifier bridge for the steady state concentration measurements and a low cost hardware cross correlation flowmeter for component velocity measurements, has been developed

  8. Accurate measurement of streamwise vortices in low speed aerodynamic flows

    NASA Astrophysics Data System (ADS)

    Waldman, Rye M.; Kudo, Jun; Breuer, Kenneth S.

    2010-11-01

    Low Reynolds number experiments with flapping animals (such as bats and small birds) are of current interest in understanding biological flight mechanics, and due to their application to Micro Air Vehicles (MAVs) which operate in a similar parameter space. Previous PIV wake measurements have described the structures left by bats and birds, and provided insight to the time history of their aerodynamic force generation; however, these studies have faced difficulty drawing quantitative conclusions due to significant experimental challenges associated with the highly three-dimensional and unsteady nature of the flows, and the low wake velocities associated with lifting bodies that only weigh a few grams. This requires the high-speed resolution of small flow features in a large field of view using limited laser energy and finite camera resolution. Cross-stream measurements are further complicated by the high out-of-plane flow which requires thick laser sheets and short interframe times. To quantify and address these challenges we present data from a model study on the wake behind a fixed wing at conditions comparable to those found in biological flight. We present a detailed analysis of the PIV wake measurements, discuss the criteria necessary for accurate measurements, and present a new dual-plane PIV configuration to resolve these issues.

  9. PIV measurements of flow around an arbitrarily moving free surface

    NASA Astrophysics Data System (ADS)

    Park, Jinsoo; Im, Sunghyuk; Sung, Hyung Jin; Park, Jun Sang

    2015-03-01

    We present an image preprocessing method for particle image velocimetry (PIV) measurements of flow around an arbitrarily moving free surface. When performing PIV measurements of free surface flows, the interrogation windows neighboring the free surface are vulnerable to a lack, or even an absence, of seeding particles, which induces less reliable measurements of the velocity field. In addition, direct measurements of the free surface velocity using PIV have been challenging due to the intermittent appearance of the arbitrarily moving free surface. To address the aforementioned limitations, the PIV images with a curvilinear free surface can be treated to be suitable for a structured interrogation window arrangement in a Cartesian grid. The proposed image preprocessing method is comprised of a free surface detection method and an image transform process. The free surface position was identified using a free surface detection method based on multiple textons. The detected free surface points were used to transform PIV images of a curvilinear free surface into images with a straightened free surface using a cubic Hermite spline interpolation scheme. After the image preprocessing, PIV algorithms can be applied to the treated PIV images. The fluid-only region velocities were measured using standard PIV method with window deformation, and the free surface velocities were resolved using PIV/interface gradiometry method. The velocity field in the original PIV images was constructed by inverse transforming that in the transformed images. The accuracy of the proposed method was quantitatively evaluated with two sets of synthetic PIV images, and its applicability was examined by applying the present method to free surface flow images, specifically sloshing flow images.

  10. Measurement of energy distribution in flowing hydrogen microwave plasmas

    NASA Technical Reports Server (NTRS)

    Chapman, R.; Morin, T.; Finzel, M.; Hawley, M. C.

    1985-01-01

    An electrothermal propulsion concept utilizing a microwave plasma system as the mechanism to convert electromagnetic energy into kinetic energy of a flowing gas is investigated. A calorimetry system enclosing a microwave plasma system has been developed to accurately measure the energy inputs and outputs of the microwave plasma system. The rate of energy transferred to the gas can be determined to within + or - 1.8 W from an energy balance around the microwave plasma system. The percentage of the power absorbed by the microwave plasma system transferred to the hydrogen gas as it flows through the system is found to increase with the increasing flow rate, to decrease with the increasing pressure, and to be independent of the absorbed power. An upper bound for the hydrogen gas temperature is estimated from the energy content, heat capacity, and flow rate of the gas stream. A lower bound for an overall heat-transfer coefficient is then calculated, characterizing the energy loss from the hydrogen gas stream to the air cooling of the plasma discharge tube wall. The heat-transfer coefficient is found to increase with the increasing flow rate and pressure and to be independent of the absorbed power. This result indicates that a convective-type mechanism is responsible for the energy transfer.

  11. Flow Measurements through natural and degraded regions of the Everglades

    NASA Astrophysics Data System (ADS)

    Variano, E. A.; Engel, V.; Schmieder, P.; Reid, M.; Ho, D. T.

    2007-12-01

    The $8 Billion Comprehensive Everglades Restoration Plan (CERP) will attempt to preserve the ecological richness of the Everglades, a unique "river of grass" and UNESCO world heritage site. However, the natural flow conditions in the Everglades are complex and poorly understood. A better understanding of flow dynamics is important not only as a target for restoration designs, but also to elucidate the mechanisms by which ridge and slough structures (low elevation land and shallow channels, respectively) are maintained by the flow. Current hypotheses include direct transport of sediment or the effects of nutrient transport on soil chemistry. We perform a set of tracer releases using Sulfur Hexafluoride (SF6) to examine these hypotheses, as well as provide information of immediate utility for any possible restoration plans in the South Florida Water Management District's WCA-3A. SF6 tracer releases offer the ability to both visualize and quantify the flow dynamics over a large area (roughly 30 ha). We measure SF6 levels to high accuracy using a uniquely rugged and portable gas extraction and chromatography unit. Using these techniques, we compare the flow in an area with relatively little degradation with areas both upstream and downstream of a typical canal/levee obstruction.

  12. Rayleigh Light Scattering for Concentration Measurements in Turbulent Flows

    NASA Technical Reports Server (NTRS)

    Pitts, William M.

    1996-01-01

    Despite intensive research over a number of years, an understanding of scalar mixing in turbulent flows remains elusive. An understanding is required because turbulent mixing has a pivotal role in a wide variety of natural and technologically important processes. As an example, the mixing and transport of pollutants in the atmosphere and in bodies of water are often dependent on turbulent mixing processes. Turbulent mixing is also central to turbulent combustion which underlies most hydrocarbon energy use in modern societies as well as in unwanted fire behavior. Development of models for combusting flows is therefore crucial, however, an understanding of scalar mixing is required before useful models of turbulent mixing and, ultimately, turbulent combustion can be developed. An important subset of turbulent flows is axisymmetric turbulent jets and plumes because they are relatively simple to generate, and because the provide an appropriate test bed for the development of general theories of turbulent mixing which can be applied to more complex geometries and flows. This paper focuses on a number of experimental techniques which have been developed at the National Institute of Standards and Development for measuring concentration in binary axisymmetric turbulent jets. In order to demonstrate the value of these diagnostics, some of the more important results from earlier and on-going investigations are summarized. Topics addressed include the similarity behavior of variable density axisymmetric jets, the behavior of absolutely unstable axisymmetric helium jets, and the role of large scale structures and scalar dissipation in these flows.

  13. Measuring material microstructure under flow using 1-2 plane flow-small angle neutron scattering.

    PubMed

    Gurnon, A Kate; Godfrin, P Douglas; Wagner, Norman J; Eberle, Aaron P R; Butler, Paul; Porcar, Lionel

    2014-01-01

    A new small-angle neutron scattering (SANS) sample environment optimized for studying the microstructure of complex fluids under simple shear flow is presented. The SANS shear cell consists of a concentric cylinder Couette geometry that is sealed and rotating about a horizontal axis so that the vorticity direction of the flow field is aligned with the neutron beam enabling scattering from the 1-2 plane of shear (velocity-velocity gradient, respectively). This approach is an advance over previous shear cell sample environments as there is a strong coupling between the bulk rheology and microstructural features in the 1-2 plane of shear. Flow-instabilities, such as shear banding, can also be studied by spatially resolved measurements. This is accomplished in this sample environment by using a narrow aperture for the neutron beam and scanning along the velocity gradient direction. Time resolved experiments, such as flow start-ups and large amplitude oscillatory shear flow are also possible by synchronization of the shear motion and time-resolved detection of scattered neutrons. Representative results using the methods outlined here demonstrate the useful nature of spatial resolution for measuring the microstructure of a wormlike micelle solution that exhibits shear banding, a phenomenon that can only be investigated by resolving the structure along the velocity gradient direction. Finally, potential improvements to the current design are discussed along with suggestions for supplementary experiments as motivation for future experiments on a broad range of complex fluids in a variety of shear motions. PMID:24561395

  14. Measuring Material Microstructure Under Flow Using 1-2 Plane Flow-Small Angle Neutron Scattering

    PubMed Central

    Gurnon, A. Kate; Godfrin, P. Douglas; Wagner, Norman J.; Eberle, Aaron P. R.; Butler, Paul; Porcar, Lionel

    2014-01-01

    A new small-angle neutron scattering (SANS) sample environment optimized for studying the microstructure of complex fluids under simple shear flow is presented. The SANS shear cell consists of a concentric cylinder Couette geometry that is sealed and rotating about a horizontal axis so that the vorticity direction of the flow field is aligned with the neutron beam enabling scattering from the 1-2 plane of shear (velocity-velocity gradient, respectively). This approach is an advance over previous shear cell sample environments as there is a strong coupling between the bulk rheology and microstructural features in the 1-2 plane of shear. Flow-instabilities, such as shear banding, can also be studied by spatially resolved measurements. This is accomplished in this sample environment by using a narrow aperture for the neutron beam and scanning along the velocity gradient direction. Time resolved experiments, such as flow start-ups and large amplitude oscillatory shear flow are also possible by synchronization of the shear motion and time-resolved detection of scattered neutrons. Representative results using the methods outlined here demonstrate the useful nature of spatial resolution for measuring the microstructure of a wormlike micelle solution that exhibits shear banding, a phenomenon that can only be investigated by resolving the structure along the velocity gradient direction. Finally, potential improvements to the current design are discussed along with suggestions for supplementary experiments as motivation for future experiments on a broad range of complex fluids in a variety of shear motions. PMID:24561395

  15. Flow velocity measurement with the nonlinear acoustic wave scattering

    SciTech Connect

    Didenkulov, Igor; Pronchatov-Rubtsov, Nikolay

    2015-10-28

    A problem of noninvasive measurement of liquid flow velocity arises in many practical applications. To this end the most often approach is the use of the linear Doppler technique. The Doppler frequency shift of signal scattered from the inhomogeneities distributed in a liquid relatively to the emitted frequency is proportional to the sound frequency and velocities of inhomogeneities. In the case of very slow flow one needs to use very high frequency sound. This approach fails in media with strong sound attenuation because acoustic wave attenuation increases with frequency and there is limit in increasing sound intensity, i.e. the cavitation threshold. Another approach which is considered in this paper is based on the method using the difference frequency Doppler Effect for flows with bubbles. This method is based on simultaneous action of two high-frequency primary acoustic waves with closed frequencies on bubbles and registration of the scattered by bubbles acoustic field at the difference frequency. The use of this method is interesting since the scattered difference frequency wave has much lower attenuation in a liquid. The theoretical consideration of the method is given in the paper. The experimental examples confirming the theoretical equations, as well as the ability of the method to be applied in medical diagnostics and in technical applications on measurement of flow velocities in liquids with strong sound attenuation is described. It is shown that the Doppler spectrum form depends on bubble concentration velocity distribution in the primary acoustic beams crossing zone that allows one to measure the flow velocity distribution.

  16. Flow velocity measurement with the nonlinear acoustic wave scattering

    NASA Astrophysics Data System (ADS)

    Didenkulov, Igor; Pronchatov-Rubtsov, Nikolay

    2015-10-01

    A problem of noninvasive measurement of liquid flow velocity arises in many practical applications. To this end the most often approach is the use of the linear Doppler technique. The Doppler frequency shift of signal scattered from the inhomogeneities distributed in a liquid relatively to the emitted frequency is proportional to the sound frequency and velocities of inhomogeneities. In the case of very slow flow one needs to use very high frequency sound. This approach fails in media with strong sound attenuation because acoustic wave attenuation increases with frequency and there is limit in increasing sound intensity, i.e. the cavitation threshold. Another approach which is considered in this paper is based on the method using the difference frequency Doppler Effect for flows with bubbles. This method is based on simultaneous action of two high-frequency primary acoustic waves with closed frequencies on bubbles and registration of the scattered by bubbles acoustic field at the difference frequency. The use of this method is interesting since the scattered difference frequency wave has much lower attenuation in a liquid. The theoretical consideration of the method is given in the paper. The experimental examples confirming the theoretical equations, as well as the ability of the method to be applied in medical diagnostics and in technical applications on measurement of flow velocities in liquids with strong sound attenuation is described. It is shown that the Doppler spectrum form depends on bubble concentration velocity distribution in the primary acoustic beams crossing zone that allows one to measure the flow velocity distribution.

  17. Internal flow-field measurements in a model can-type gas-turbine combustion chamber

    NASA Astrophysics Data System (ADS)

    Koutmos, P.; McQuirk, J. J.; Vafidis, C.

    LDA measurements of the three mean velocity components and the corresponding turbulence intensities have been made to provide qualitative and quantitative information on the flow-field in a water model of a can-type gas turbine combustion chamber. The combustor geometry comprised a swirl driven primary zone, annulus fed rows of primary and secondary jets and an exit contraction nozzle. Flow visualization revealed a stable and symmetric vortex established within the primary zone via the combined effects of the inlet swirl and primary jet impingement. High levels of turbulence kinetic energy were generated within the vortex as well as near the location where the jets impinged. Large streamline curvature, anisotropy of the turbulence structure and very rapid transfer of momentum from the radial to the axial direction were associated with this primary region. In the downstream dilution zone a shallower jet trajectory was observed and the larger turbulence kinetic energy levels could be identified in this region with the shear layers formed between the bulk flow emerging from the primary zone and the incoming secondary jets. Moderate levels of spatial non-uniformities were measured at the exit from the nozzle.

  18. Basic data for some recent Australian heat-flow measurements

    USGS Publications Warehouse

    Munroe, Robert J.; Sass, J.H.; Milburn, G.T.; Jaeger, J.C.; Tammemagi, H.Y.

    1975-01-01

    This report has been compiled to provide background information and detailed temperature and thermal conductivity data for the heat-flow values reported in Sass, Jaeger, and Munroe (in press). The data were collected as part of a joint heat-flow study by the Australian National University (ANU) and the U.S. Geological Survey (USGS) under the direction of J. C. Jaeger (ANU) and J. H. Sass (USGS). The format is similar to that used for basic data from United States heat-flow determinations (Sass and Munroe, 1974). Each section contains a state map showing the geographic distribution of heat-flow data followed by tables which list individual temperatures, thermal conductivities, and radiogenic heat production values. A companion volume (Bunker and others, 1975) gives details of the heat-production measurements together with individual radioelement concentrations. Localities are arranged in alphabetical order within each state. The methods and techniques of measurements have been described by Sass and others (1971a, b). Unusual methods or procedures which differ markedly from these techniques are noted and described in the comments sections of the tables.

  19. Nanofibril Alignment in Flow Focusing: Measurements and Calculations.

    PubMed

    Håkansson, Karl M O; Lundell, Fredrik; Prahl-Wittberg, Lisa; Söderberg, L Daniel

    2016-07-14

    Alignment of anisotropic supermolecular building blocks is crucial to control the properties of many novel materials. In this study, the alignment process of cellulose nanofibrils (CNFs) in a flow-focusing channel has been investigated using small-angle X-ray scattering (SAXS) and modeled using the Smoluchowski equation, which requires a known flow field as input. This flow field was investigated experimentally using microparticle-tracking velocimetry and by numerically applying the two-fluid level set method. A semidilute dispersion of CNFs was modeled as a continuous phase, with a higher viscosity as compared to that of water. Furthermore, implementation of the Smoluchowski equation also needed the rotational Brownian diffusion coefficient, which was experimentally determined in a shear viscosity measurement. The order of the nanofibrils was found to increase during extension in the flow-focusing channel, after which rotational diffusion acted on the orientation distribution, driving the orientation of the fibrils toward isotropy. The main features of the alignment and dealignment processes were well predicted by the numerical model, but the model overpredicted the alignment at higher rates of extension. The apparent rotational diffusion coefficient was seen to increase steeply as the degree of alignment increased. Thus, the combination of SAXS measurements and modeling provides the necessary framework for quantified studies of hydrodynamic alignment, followed by relaxation toward isotropy. PMID:27294285

  20. Nuclear magnetic resonance and transcutaneous electromagnetic blood flow measurement.

    PubMed

    Battocletti, J H; Halbach, R E; Salles-Cunha, S X; Sances, A

    1983-09-01

    Static and alternating magnetic fields are employed in blood flowmeters using nuclear magnetic resonance (NMR) principles and electromagnetic induction by a moving conductor (TEM). Both techniques require high steady magnetic fields, obtained either from permanent magnets or from electromagnets. A relatively homogeneous magnetic field is needed for NMR, but, though important for calibration, homogeneity is not critical for TEM. NMR is more complex than TEM since it requires radio-frequency and audio-frequency magnetic fields. However, the TEM method requires surface electrodes in contact with the skin, or needle electrodes placed subcutaneously, whereas NMR is contactless. The NMR flowmeter can be calibrated directly, but appropriate and approximate models must be assumed and then solved by computer to quantify blood flow by the TEM flowmeter. Flow in individual vessels is measured a priori in the TEM flowmeter by virtue of the assumed models. To measure flow in individual vessels by NMR, a scanning or ranging method is required, which logically leads to blood flow imaging. The levels of steady, radio-frequency, and audio-frequency magnetic fields used in the two types of flowmeters are low enough so as not to cause any apparent stimulus to human volunteers and patients tested. PMID:6228667

  1. Optically measured microvascular blood flow contrast of malignant breast tumors.

    PubMed

    Choe, Regine; Putt, Mary E; Carlile, Peter M; Durduran, Turgut; Giammarco, Joseph M; Busch, David R; Jung, Ki Won; Czerniecki, Brian J; Tchou, Julia; Feldman, Michael D; Mies, Carolyn; Rosen, Mark A; Schnall, Mitchell D; DeMichele, Angela; Yodh, Arjun G

    2014-01-01

    Microvascular blood flow contrast is an important hemodynamic and metabolic parameter with potential to enhance in vivo breast cancer detection and therapy monitoring. Here we report on non-invasive line-scan measurements of malignant breast tumors with a hand-held optical probe in the remission geometry. The probe employs diffuse correlation spectroscopy (DCS), a near-infrared optical method that quantifies deep tissue microvascular blood flow. Tumor-to-normal perfusion ratios are derived from thirty-two human subjects. Mean (95% confidence interval) tumor-to-normal ratio using surrounding normal tissue was 2.25 (1.92-2.63); tumor-to-normal ratio using normal tissues at the corresponding tumor location in the contralateral breast was 2.27 (1.94-2.66), and using normal tissue in the contralateral breast was 2.27 (1.90-2.70). Thus, the mean tumor-to-normal ratios were significantly different from unity irrespective of the normal tissue chosen, implying that tumors have significantly higher blood flow than normal tissues. Therefore, the study demonstrates existence of breast cancer contrast in blood flow measured by DCS. The new, optically accessible cancer contrast holds potential for cancer detection and therapy monitoring applications, and it is likely to be especially useful when combined with diffuse optical spectroscopy/tomography. PMID:24967878

  2. Parallel strip waveguide for ultrasonic flow measurement in harsh environments.

    PubMed

    Laws, Michael; Ramadas, Sivaram N; Lynnworth, Lawrence C; Dixon, Steve

    2015-04-01

    Wetted ultrasonic transit time flow meters typically consist of one or more pairs of transducers, containing piezoelectric elements, which alternate between transmitting and detecting an ultrasonic pulse. Typical piezoelectric materials and the adhesives used to attach the piezoelectric element in such devices can be damaged by hostile environments, such as extreme temperature, potentially limiting possible applications of ultrasonic flow measurement techniques. We have investigated a design for a flow meter with an integrated thermal buffer waveguide consisting of five parallel stainless steel strips. These, in addition to thermal protection, may function as a transducer array, with the possibility of steering the emitted field. Because the buffer strips used in the transducer assembly are thin, one might expect Lamb-like guided waves to propagate along it. However, the finite width of the strips has a significant effect on the propagation characteristics of the guided waves. In this work, the effect of the waveguide's small rectangular cross-section has been studied. Additionally, we have examined the effect of thermal gradients on the average sound speed and dispersion characteristics of such strip waveguides. We also suggest modifications to the plate geometry, which can alter both the frequency content and the shape of the transmitted pulse, potentially giving a better signal to use in flow measurement. PMID:25881347

  3. Stochastic Measurement Models for Quantifying Lymphocyte Responses Using Flow Cytometry

    PubMed Central

    Kan, Andrey; Pavlyshyn, Damian; Markham, John F.; Dowling, Mark R.; Heinzel, Susanne; Zhou, Jie H. S.; Marchingo, Julia M.; Hodgkin, Philip D.

    2016-01-01

    Adaptive immune responses are complex dynamic processes whereby B and T cells undergo division and differentiation triggered by pathogenic stimuli. Deregulation of the response can lead to severe consequences for the host organism ranging from immune deficiencies to autoimmunity. Tracking cell division and differentiation by flow cytometry using fluorescent probes is a major method for measuring progression of lymphocyte responses, both in vitro and in vivo. In turn, mathematical modeling of cell numbers derived from such measurements has led to significant biological discoveries, and plays an increasingly important role in lymphocyte research. Fitting an appropriate parameterized model to such data is the goal of these studies but significant challenges are presented by the variability in measurements. This variation results from the sum of experimental noise and intrinsic probabilistic differences in cells and is difficult to characterize analytically. Current model fitting methods adopt different simplifying assumptions to describe the distribution of such measurements and these assumptions have not been tested directly. To help inform the choice and application of appropriate methods of model fitting to such data we studied the errors associated with flow cytometry measurements from a wide variety of experiments. We found that the mean and variance of the noise were related by a power law with an exponent between 1.3 and 1.8 for different datasets. This violated the assumptions inherent to commonly used least squares, linear variance scaling and log-transformation based methods. As a result of these findings we propose a new measurement model that we justify both theoretically, from the maximum entropy standpoint, and empirically using collected data. Our evaluation suggests that the new model can be reliably used for model fitting across a variety of conditions. Our work provides a foundation for modeling measurements in flow cytometry experiments thus

  4. Stochastic Measurement Models for Quantifying Lymphocyte Responses Using Flow Cytometry.

    PubMed

    Kan, Andrey; Pavlyshyn, Damian; Markham, John F; Dowling, Mark R; Heinzel, Susanne; Zhou, Jie H S; Marchingo, Julia M; Hodgkin, Philip D

    2016-01-01

    Adaptive immune responses are complex dynamic processes whereby B and T cells undergo division and differentiation triggered by pathogenic stimuli. Deregulation of the response can lead to severe consequences for the host organism ranging from immune deficiencies to autoimmunity. Tracking cell division and differentiation by flow cytometry using fluorescent probes is a major method for measuring progression of lymphocyte responses, both in vitro and in vivo. In turn, mathematical modeling of cell numbers derived from such measurements has led to significant biological discoveries, and plays an increasingly important role in lymphocyte research. Fitting an appropriate parameterized model to such data is the goal of these studies but significant challenges are presented by the variability in measurements. This variation results from the sum of experimental noise and intrinsic probabilistic differences in cells and is difficult to characterize analytically. Current model fitting methods adopt different simplifying assumptions to describe the distribution of such measurements and these assumptions have not been tested directly. To help inform the choice and application of appropriate methods of model fitting to such data we studied the errors associated with flow cytometry measurements from a wide variety of experiments. We found that the mean and variance of the noise were related by a power law with an exponent between 1.3 and 1.8 for different datasets. This violated the assumptions inherent to commonly used least squares, linear variance scaling and log-transformation based methods. As a result of these findings we propose a new measurement model that we justify both theoretically, from the maximum entropy standpoint, and empirically using collected data. Our evaluation suggests that the new model can be reliably used for model fitting across a variety of conditions. Our work provides a foundation for modeling measurements in flow cytometry experiments thus

  5. Flow cytometric measurement of total DNA and incorporated halodeoxyuridine

    DOEpatents

    Dolbeare, Frank A.; Gray, Joe W.

    1988-01-01

    A method for the simultaneous flow cytometric measurement of the total DNA content and the level of DNA synthesis in normal and malignant cells is disclosed. The sensitivity of the method allows a study of cell cycle traverse rates for large scale cell populations as well as single cell measurements. A DNA stain such as propidium iodide or Hoechst 33258 is used as the probe for the measurement of total DNA content and a monoclonal antibody reactive with a DNA precursor such as halodeoxy-uridine (HdU), more specifically bromodeoxyuridine (BrdU) is used as a probe for the measurement of HdU or BrdU uptake by the cells as a measure of DNA synthesis.

  6. Flow cytometric measurement of total DNA and incorporated halodeoxyuridine

    DOEpatents

    Dolbeare, F.A.; Gray, J.W.

    1983-10-18

    A method for the simultaneous flow cylometric measurement of total cellular DNA content and of the uptake of DNA precursors as a measure of DNA synthesis during various phases of the cell cycle in normal and malignant cells in vitro and in vivo is described. The method comprises reacting cells with labelled halodeoxyuridine (HdU), partially denaturing cellular DNA, adding to the reaction medium monoclonal antibodies (mabs) reactive with HdU, reacting the bound mabs with a second labelled antibody, incubating the mixture with a DNA stain, and measuring simultaneously the intensity of the DNA stain as a measure of the total cellular DNA and the HdU incorporated as a measure of DNA synthesis. (ACR)

  7. Deformation-phase measurement by optical flow method

    NASA Astrophysics Data System (ADS)

    Zhao, Ran; Sun, Ping

    2016-07-01

    A novel algorithm which extract the out-of-plane component of deformation-phase from two continuous fringe patterns is proposed. The whole-field out-of-plane component of deformation-phase map is obtained by the estimations of the optical flow velocity field between two images and the local frequency of the original image. In this paper, the proposed algorithm is introduced and applied to simulated and experimental interferograms. Simulation and experimental results show that the new method can demodulate the out-of-plane component of deformation-phase from the visible optical flow velocity field without the operation of phase unwrapping. Further, the proposed algorithm provides a new approach for whole-field deformation-phase measurement and dynamic deformation measurement.

  8. The laser measurement technology of combustion flow field

    NASA Astrophysics Data System (ADS)

    Wang, Mingdong; Wang, Guangyu; Qu, Dongsheng

    2014-07-01

    The parameters of combustion flow field such as temperature, velocity, pressure and mole-fraction are of significant value in engineering application. The laser spectroscopy technology which has the non-contact and non- interference properties has become the most important method and it has more advantages than conventionally contacting measurement. Planar laser induced fluorescence (PLIF/LIF) is provided with high sensibility and resolution. Filtered Rayleigh scattering (FRS) is a good measurement method for complex flow field .Tunable diode laser absorption spectroscopy (TDLAS) is prosperity on development and application. This article introduced the theoretical foundation, technical principle, system structure, merits and shortages. It is helpful for researchers to know about the latest development tendency and do the related research.

  9. Factors affecting measurement of channel thickness in asymmetrical flow field-flow fractionation.

    PubMed

    Dou, Haiyang; Jung, Euo Chang; Lee, Seungho

    2015-05-01

    Asymmetrical flow field-flow fractionation (AF4) has been considered to be a useful tool for simultaneous separation and characterization of polydisperse macromolecules or colloidal nanoparticles. AF4 analysis requires the knowledge of the channel thickness (w), which is usually measured by injecting a standard with known diffusion coefficient (D) or hydrodynamic diameter (dh). An accurate w determination is a challenge due to its uncertainties arising from the membrane's compressibility, which may vary with experimental condition. In the present study, influence of factors including the size and type of the standard on the measurement of w was systematically investigated. The results revealed that steric effect and the particles-membrane interaction by van der Waals or electrostatic force may result in an error in w measurement. PMID:25817708

  10. Ultrasonic Doppler measurement of renal artery blood flow

    NASA Technical Reports Server (NTRS)

    Freund, W. R.; Meindl, J. D.

    1975-01-01

    An extensive evaluation of the practical and theoretical limitations encountered in the use of totally implantable CW Doppler flowmeters is provided. Theoretical analyses, computer models, in-vitro and in-vivo calibration studies describe the sources and magnitudes of potential errors in the measurement of blood flow through the renal artery, as well as larger vessels in the circulatory system. The evaluation of new flowmeter/transducer systems and their use in physiological investigations is reported.

  11. Optical Vortex Metrology: Displacement and Flow Measurements with Phase Singularities

    NASA Astrophysics Data System (ADS)

    Takeda, Mitsuo; Wang, Wei; Hanson, Steen G.; Miyamoto, Yoko

    2007-10-01

    We review the principle and the applications of a new technique which we recently proposed for displacement and flow measurements. The technique is called optical vortex metrology because it makes use of phase singularities in the complex signal as markers or tracers, which are generated by a vortex filer that performs a Riesz or Laguerre-Gauss transform operation to a speckle-like random pattern.

  12. Measuring and Optimizing flows in the Madison Dynamo Experiment

    NASA Astrophysics Data System (ADS)

    Taylor, N. Z.; Clark, M.; Forest, C. B.; Kaplan, E. J.; Nornberg, M. D.; Rasmus, A. M.; Rahbarnia, K.

    2012-10-01

    In the Madison Dynamo Experiment, two counter-rotating impellers drive a turbulent flow of liquid sodium in a one meter-diameter sphere. One of the goals of the experiment is to observe a magnetic field grow at the expense of kinetic energy in the flow. The enormous Reynolds number of the experiment and its two vortex geometry leads to a large turbulent EMF. This poster presents results from the MDE after several upgrades were made. First, an equatorial baffle was installed to stabilize the position of the shear layer between the two counterrotating hemispheres. This reduced the scale of the largest eddies in the experiment, lowering the effective resistivity due to turbulence. Next, a probe was used to measure both the fluctuating velocity and magnetic fields, enabling a direct measurement of the turbulent EMF. This EMF is anti-parallel to the mean current, consistent with an enhanced resistivity predicted by mean field theory. Finally, vanes with adjustable orientation were installed on the vessel wall, allowing the pitch of the helical flow to be altered. Computational fluid dynamics simulations and inversion of the measured induced magnetic field are used to determine the optimum angle of these vanes to minimize the critical velocity at which the dynamo onset occurs.

  13. Intraglomerular microcirculation: measurements of single glomerular loop flow in rats.

    PubMed

    Steinhausen, M; Zimmerhackl, B; Thederan, H; Dussel, R; Parekh, N; Esslinger, H U; von Hagens, G; Komitowski, D; Dallenbach, F D

    1981-08-01

    With the use of a new fluorescent microscopic technique, we were able to measure the mean intracapillary velocities and pressures of single capillary loops of renal glomeruli of living rats. The technique involved photographing and recording the flow of fluorescent latex particles through the glomerular loops with a television monitor. In 25 rats the single glomerular loop flow velocity was 781 +/- (SD) 271 micrometers . sec-1. The mean diameter of the capillary loops measured 8.4 +/- 1.4 micrometers; their lengths were 72.3 +/- 37.5 micrometers. From the decrease in velocity of flow along the capillary loop, we were able to evaluate the filtration equivalent for the capillary surface. It was possible to measure intracapillary pressures of single glomerular loops continuously under microscopic control. High intracapillary pressures correlated with high intracapillary velocities. From the data we obtained, we were unable to calculate a filtration equilibrium at the ends of the observed capillary loops. For further correlations, we injected the glomeruli we had studied in the living state and examined them with the scanning electron microscope. PMID:7289407

  14. Measurement of AC Induced Flow using Mico PIV

    NASA Astrophysics Data System (ADS)

    Wang, Dazhi; Meinhart, Carl; Sigurdson, Marin

    2002-11-01

    The fluid motion in a wedge-shaped device subject to an AC electric field is measured using Micron-Resolution Particle Image Velocimetry (micro-PIV). The fluorescent polystyrene spherical particles are used as flow tracers. In the non-uniform electric field, the particles in the suspension experience dielectrophoretic forces, which cause difference of velocities between the particles and the fluid. In order to eliminate the velocity difference, two different size particles are used for the micro-PIV measurements to determine the fluid velocity field. A two-color PIV technique is used to determine uniquely the fluid velocity field. The wedge-shaped channel is 100-micron wide at the apex, and fabricated from a 550-micron thick silicon wafer. A voltage of 15Vrms at 100 kHz is applied to the electrodes. The particle volume fraction is set below 0.1% so that the effect of the particles on the fluid can be negligible. Fifty successive images are taken to record particle images and analyzed to estimate the particle velocity fields. The velocity fields of the two different size particles are then used to uniquely determine the underlying fluid velocity. The measured fluid flow is a saddle-point flow, which could be used for precision mixing and transport in microscale devices.

  15. SEWER FLOW MEASUREMENT: A STATE-OF-THE-ART ASSESSMENT (EPA/600/2-75/027)

    EPA Science Inventory

    A brief review of the characteristics of storm and combined sewer flows is given, followed by a general discussion of the need for such flow measurement, the types of flow data required, and the time element in flow data. A discussion of desirable flow measuring equipment charact...

  16. 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

  17. Verifying a Simplified Fuel Oil Flow Field Measurement Protocol

    SciTech Connect

    Henderson, H.; Dentz, J.; Doty, C.

    2013-07-01

    The Better Buildings program is a U.S. Department of Energy program funding energy efficiency retrofits in buildings nationwide. The program is in need of an inexpensive method for measuring fuel oil consumption that can be used in evaluating the impact that retrofits have in existing properties with oil heat. This project developed and verified a fuel oil flow field measurement protocol that is cost effective and can be performed with little training for use by the Better Buildings program as well as other programs and researchers.

  18. Gas and liquid measurements in air-water bubbly flows

    SciTech Connect

    Zhou, X.; Doup, B.; Sun, X.

    2012-07-01

    Local measurements of gas- and liquid-phase flow parameters are conducted in an air-water two-phase flow loop. The test section is a vertical pipe with an inner diameter of 50 mm and a height of 3.2 m. The measurements are performed at z/D = 10. The gas-phase measurements are performed using a four-sensor conductivity probe. The data taken from this probe are processed using a signal processing program to yield radial profiles of the void fraction, bubble velocity, and interfacial area concentration. The velocity measurements of the liquid-phase are performed using a state-of-the-art Particle Image Velocimetry (PIV) system. The raw PIV images are acquired using fluorescent particles and an optical filtration device. Image processing is used to remove noise in the raw PIV images. The statistical cross correlation is introduced to determine the axial velocity field and turbulence intensity of the liquid-phase. Measurements are currently being performed at z/D = 32 to provide a more complete data set. These data can be used for computational fluid dynamic model development and validation. (authors)

  19. Nonintrusive, multipoint velocity measurements in high-pressure combustion flows

    NASA Technical Reports Server (NTRS)

    Allen, M.; Davis, S.; Kessler, W.; Legner, H.; Mcmanus, K.; Mulhall, P.; Parker, T.; Sonnenfroh, D.

    1993-01-01

    A combined experimental and analytical effort was conducted to demonstrate the applicability of OH Doppler-shifted fluorescence imaging of velocity distributions in supersonic combustion gases. The experiments were conducted in the underexpanded exhaust flow from a 6.8 atm, 2400 K, H2-O2-N2 burner exhausting into the atmosphere. In order to quantify the effects of in-plane variations of the gas thermodynamic properties on the measurement accuracy, a set of detailed measurements of the OH (1,0) band collisional broadening and shifting in H2-air gases was produced. The effect of pulse-to-pulse variations in the dye laser bandshape was also examined in detail and a modification was developed which increased in the single pulse bandwidth, thereby increasing the intraimage velocity dynamic range as well as reducing the sensitivity of the velocity measurement to the gas property variations. Single point and imaging measurements of the velocity field in the exhaust flowfield were compared with 2D, finite-rate kinetics simulations of the flowfield. Relative velocity accuracies of +/- 50 m/s out of 1600 m/s were achieved in time-averaged imaging measurements of the flow over an order of magnitude variation in pressure and a factor of two variation in temperature.

  20. Laser velocimeter measurements of multiphase flow of solids

    SciTech Connect

    Kadambi, J.R.; Chen, R.C.; Bhunia, S.

    1989-01-01

    A unique refractive index matched facility for studying solid-liquid multiphase flow has been developed. The refractive index matching of the solid and the liquid allows the use of non-intrusive Laser Doppler Velocimetry (LDV) to measure the solid and the liquid velocities. These measurements will be useful in developing a better understanding of solid-liquid flows, especially solid-liquid and solid-solid interactions. Silica gel and 50% sodium iodide solution in water (refractive index {approx}1.443) are used as the refractive index matched solid and liquid respectively. A two color back scatter mode LDV is used for making velocity measurements. Tests were conducted in solid-liquid slurries with volumetric solid concentration levels of 5% and 15% in the Reynolds number (Re) range of 400 to 9200. Silica gel particles of mean diameter 40 microns were used. Measurements included mapping of the solid and liquid velocities and obtaining the pressure drop data. Signal processing technique utilizing histogram of velocity measurements made at a point and signal amplitude discrimination was successfully used for differentiating between solid and liquid velocities. 34 refs., 61 figs., 5 tabs.

  1. Real-time precision concentration measurement for flowing liquid solutions

    NASA Astrophysics Data System (ADS)

    Krishna, V.; Fan, C. H.; Longtin, J. P.

    2000-10-01

    The precise, real-time measurement of liquid concentration is important in fundamental research, chemical analysis, mixing processes, and manufacturing, e.g., in the food and semiconductor industries. This work presents a laser-based, noninvasive technique to measure concentration changes of flowing liquids in real time. The essential components in the system include a 5 mW laser diode coupled to a single-mode optical fiber, a triangular optical cell, and a high-resolution beam position sensor. The instrument provides a large range of concentration measurement, typically 0%-100% for binary liquid mixtures, while providing a resolution on the order of 0.05% concentration or better. The experimental configuration is small, reliable, and inexpensive. Results are presented for NaCl and MgCl2 aqueous solutions with concentrations ranging from 0% to 25%, with very good agreement found between measured and true concentrations.

  2. Fluid flow measurements by means of vibration monitoring

    NASA Astrophysics Data System (ADS)

    Campagna, Mauro M.; Dinardo, Giuseppe; Fabbiano, Laura; Vacca, Gaetano

    2015-11-01

    The achievement of accurate fluid flow measurements is fundamental whenever the control and the monitoring of certain physical quantities governing an industrial process are required. In that case, non-intrusive devices are preferable, but these are often more sophisticated and expensive than those which are more common (such as nozzles, diaphrams, Coriolis flowmeters and so on). In this paper, a novel, non-intrusive, simple and inexpensive methodology is presented to measure the fluid flow rate (in a turbulent regime) whose physical principle is based on the acquisition of transversal vibrational signals induced by the fluid itself onto the pipe walls it is flowing through. Such a principle of operation would permit the use of micro-accelerometers capable of acquiring and transmitting the signals, even by means of wireless technology, to a control room for the monitoring of the process under control. A possible application (whose feasibility will be investigated by the authors in a further study) of this introduced technology is related to the employment of a net of micro-accelerometers to be installed on pipeline networks of aqueducts. This apparatus could lead to the faster and easier detection and location of possible leaks of fluid affecting the pipeline network with more affordable costs. The authors, who have previously proven the linear dependency of the acceleration harmonics amplitude on the flow rate, here discuss an experimental analysis of this functional relation with the variation in the physical properties of the pipe in terms of its diameter and constituent material, to find the eventual limits to the practical application of the measurement methodology.

  3. Acoustic measurement of the Deepwater Horizon Macondo well flow rate

    PubMed Central

    Camilli, Richard; Di Iorio, Daniela; Bowen, Andrew; Reddy, Christopher M.; Techet, Alexandra H.; Yoerger, Dana R.; Whitcomb, Louis L.; Seewald, Jeffrey S.; Sylva, Sean P.; Fenwick, Judith

    2012-01-01

    On May 31, 2010, a direct acoustic measurement method was used to quantify fluid leakage rate from the Deepwater Horizon Macondo well prior to removal of its broken riser. This method utilized an acoustic imaging sonar and acoustic Doppler sonar operating onboard a remotely operated vehicle for noncontact measurement of flow cross-section and velocity from the well’s two leak sites. Over 2,500 sonar cross-sections and over 85,000 Doppler velocity measurements were recorded during the acquisition process. These data were then applied to turbulent jet and plume flow models to account for entrained water and calculate a combined hydrocarbon flow rate from the two leak sites at seafloor conditions. Based on the chemical composition of end-member samples collected from within the well, this bulk volumetric rate was then normalized to account for contributions from gases and condensates at initial leak source conditions. Results from this investigation indicate that on May 31, 2010, the well’s oil flow rate was approximately 0.10 ± 0.017 m3 s-1 at seafloor conditions, or approximately 85 ± 15 kg s-1 (7.4 ± 1.3 Gg d-1), equivalent to approximately 57,000 ± 9,800 barrels of oil per day at surface conditions. End-member chemical composition indicates that this oil release rate was accompanied by approximately an additional 24 ± 4.2 kg s-1 (2.1 ± 0.37 Gg d-1) of natural gas (methane through pentanes), yielding a total hydrocarbon release rate of 110 ± 19 kg s-1 (9.5 ± 1.6 Gg d-1). PMID:21903931

  4. Sap flow measurements to determine the transpiration of facade greenings

    NASA Astrophysics Data System (ADS)

    Hölscher, Marie-Therese; Nehls, Thomas; Wessolek, Gerd

    2014-05-01

    Facade greening is expected to make a major contribution to the mitigation of the urban heat-island effect through transpiration cooling, thermal insulation and shading of vertical built structures. However, no studies are available on water demand and the transpiration of urban vertical green. Such knowledge is needed as the plants must be sufficiently watered, otherwise the posited positive effects of vertical green can turn into disadvantages when compared to a white wall. Within the framework of the German Research Group DFG FOR 1736 "Urban Climate and Heat Stress" this study aims to test the practicability of the sap flow technique for transpiration measurements of climbing plants and to obtain potential transpiration rates for the most commonly used species. Using sap flow measurements we determined the transpiration of Fallopia baldschuanica, Parthenocissus tricuspidata and Hedera helix in pot experiments (about 1 m high) during the hot summer period from August 17th to August 30th 2012 under indoor conditions. Sap flow measurements corresponded well to simultaneous weight measurement on a daily base (factor 1.19). Fallopia baldschuanica has the highest daily transpiration rate based on leaf area (1.6 mm d-1) and per base area (5.0 mm d-1). Parthenocissus tricuspidata and Hedera helix show transpiration rates of 3.5 and 0.4 mm d-1 (per base area). Through water shortage, transpiration strongly decreased and leaf temperature measured by infrared thermography increased by 1 K compared to a well watered plant. We transferred the technique to outdoor conditions and will present first results for facade greenings in the inner-city of Berlin for the hottest period in summer 2013.

  5. Measurement of entropy generation within bypass transitional flow

    NASA Astrophysics Data System (ADS)

    Skifton, Richard; Budwig, Ralph; McEligot, Donald; Crepeau, John

    2013-11-01

    A flat plate made from quartz was submersed in the Idaho National Laboratory's Matched Index of Refraction flow facility. Particle Image Velocimetry and Particle Tracking Velocimetry were utilized to capture spatial vector maps at near wall locations within a transitional boundary layer. Entropy generation was then calculated directly from measured velocity vector fields using an integral approach. Two flows were studied: a Zero Pressure Gradient (ZPG) and an Adverse Pressure Gradient (APG), with β ~ -0.039. Near the leading edge of the plate, the free stream turbulence intensity (FSTI) to drive bypass transition was 7.5% and 4.25% for the ZPG and APG, respectively. Towards the downstream side of the plate, the FSTI was 2.5% and 3% for ZPG and APG, respectively. The integral approach for entropy generation rate, within the transitional region of flow, will be utilized as a design parameter to systematically reduce losses. As a second observation, the entropy generation can be shown to predict the onset of transitional flow. This research was funded by the DOE EPSCoR program No. DE-SC0004751, and by funding received from the DOE Office of Nuclear Energy's Nuclear Energy University Programs

  6. Measuring gas flow rates in the Milky Way

    NASA Astrophysics Data System (ADS)

    Wakker, Bart

    2010-09-01

    Gas flows out of and into the Milky Way are a crucial element in its evolution. Supernovae heat gas in the disk and lift it into the halo. Tidal streams and instabilities in the hot Galactic corona result in an inflow of low-metallicity gas. These flows can be observed in the form of the high-velocity clouds {HVCs}. Their location, brightness, distances, ionization structure and metallicities can be used to determine the conditions in the gaseous disk and halo as well as the rate of mass flow corresponding to the different processes. So far, sufficient information to derive an associated mass flow rate is available for just 5 HVCs. We propose to observe 20 AGNs toward most of the other HVC complexes as well as toward a few small clouds, in order to derive a metallicity for almost every HVC complex, which will complement distance measurements that have been or will be obtained in our ongoing program. Combining all the data, we can derive {a} the rate of the circulation of gas between disk and halo, constraining the Galactic supernova rate and {b} the accretion rate of low-metallicity material that feeds star formation over 10 Gyr, which will constrain both models of galactic chemical evolution and models of the conditions in the hot galactic corona.

  7. Highly accurate thermal flow microsensor for continuous and quantitative measurement of cerebral blood flow.

    PubMed

    Li, Chunyan; Wu, Pei-ming; Wu, Zhizhen; Limnuson, Kanokwan; Mehan, Neal; Mozayan, Cameron; Golanov, Eugene V; Ahn, Chong H; Hartings, Jed A; Narayan, Raj K

    2015-10-01

    Cerebral blood flow (CBF) plays a critical role in the exchange of nutrients and metabolites at the capillary level and is tightly regulated to meet the metabolic demands of the brain. After major brain injuries, CBF normally decreases and supporting the injured brain with adequate CBF is a mainstay of therapy after traumatic brain injury. Quantitative and localized measurement of CBF is therefore critically important for evaluation of treatment efficacy and also for understanding of cerebral pathophysiology. We present here an improved thermal flow microsensor and its operation which provides higher accuracy compared to existing devices. The flow microsensor consists of three components, two stacked-up thin film resistive elements serving as composite heater/temperature sensor and one remote resistive element for environmental temperature compensation. It operates in constant-temperature mode (~2 °C above the medium temperature) providing 20 ms temporal resolution. Compared to previous thermal flow microsensor based on self-heating and self-sensing design, the sensor presented provides at least two-fold improvement in accuracy in the range from 0 to 200 ml/100 g/min. This is mainly achieved by using the stacked-up structure, where the heating and sensing are separated to improve the temperature measurement accuracy by minimization of errors introduced by self-heating. PMID:26256480

  8. Measurement of flow diverter hydraulic resistance to model flow modification in and around intracranial aneurysms

    PubMed Central

    Szikora, István; Paál, György

    2014-01-01

    Flow diverters (FDs) have been successfully applied in the recent decade to the treatment of intracranial aneurysms by impairing the communication between the flows in the parent artery and the aneurysm and, thus, the blood within the aneurysm sac. It would be desirable to have a simple and accurate computational method to follow the changes in the peri- and intraaneurysmal flow caused by the presence of FDs. The detailed flow simulation around the intricate wire structure of the FDs has three disadvantages: need for high amount of computational resources and highly skilled professionals to prepare the computational grid, and also the lack of validation that makes the invested effort questionable. In this paper, we propose a porous layer method to model the hydraulic resistance (HR) of one or several layers of the FDs. The basis of this proposal is twofold: first, from an application point of view, the only interesting parameter regarding the function of the FD is its HR; second, we have developed a method to measure the HR with a simple apparatus. We present the results of these measurements and demonstrate their utility in numerical simulations of patient-specific aneurysm simulations. PMID:24936307

  9. Measurement of microvesicle levels in human blood using flow cytometry.

    PubMed

    Chandler, Wayne L

    2016-07-01

    Microvesicles are fragments of cells released when the cells are activated, injured, or apoptotic. Analysis of microvesicle levels in blood has the potential to shed new light on the pathophysiology of many diseases. Flow cytometry is currently the only method that can simultaneously separate true lipid microvesicles from other microparticles in blood, determine the cell of origin and other microvesicle characteristics, and handle large numbers of clinical samples with a reasonable effort, but expanded use of flow cytometric measurement of microvesicle levels as a clinical and research tool requires improved, standardized assays. The goal of this review is to aid investigators in applying current best practices to microvesicle measurements. First pre-analytical factors are evaluated and data summarized for anticoagulant effects, sample transport and centrifugation. Next flow cytometer optimization is reviewed including interference from background in buffers and reagents, accurate microvesicle counting, swarm interference, and other types of coincidence errors, size calibration, and detection limits using light scattering, impedance and fluorescence. Finally current progress on method standardization is discussed and a summary of current best practices provided. © 2016 Clinical Cytometry Society. PMID:26606416

  10. Surface pressure measurements for CFD code validation in hypersonic flow

    SciTech Connect

    Oberkampf, W.L.; Aeschliman, D.P.; Henfling, J.F.; Larson, D.E.

    1995-07-01

    Extensive surface pressure measurements were obtained on a hypersonic vehicle configuration at Mach 8. All of the experimental results were obtained in the Sandia National Laboratories Mach 8 hypersonic wind tunnel for laminar boundary layer conditions. The basic vehicle configuration is a spherically blunted 10{degrees} half-angle cone with a slice parallel with the axis of the vehicle. The bluntness ratio of the geometry is 10% and the slice begins at 70% of the length of the vehicle. Surface pressure measurements were obtained for angles of attack from {minus}10 to + 18{degrees}, for various roll angles, at 96 locations on the body surface. A new and innovative uncertainty analysis was devised to estimate the contributors to surface pressure measurement uncertainty. Quantitative estimates were computed for the uncertainty contributions due to the complete instrumentation system, nonuniformity of flow in the test section of the wind tunnel, and variations in the wind tunnel model. This extensive set of high-quality surface pressure measurements is recommended for use in the calibration and validation of computational fluid dynamics codes for hypersonic flow conditions.

  11. Application of Lorentz force techniques for flow rate measurement

    NASA Astrophysics Data System (ADS)

    Ebert, Reschad Johann; Resagk, Christian

    2014-11-01

    We report on the progress of the Lorentz force velocimetry (LFV): a contactless non-invasive flow velocity measurement technique. This method has been developed and demonstrated for various applications in our institute and in industry. At applications for weakly conducting fluids such as electrolytes with conductivities in the range of 1 - 10 S/m the challenging bottleneck is the detection of the tiny Lorentz forces in the noisy environment of the test channel. For the force measurement a state-of-the-art electromagnetic force compensation balance is used. Due to this device the mass of the Lorentz force generating magnets is limited. For enabling larger magnet systems and for higher force signals we have developed and tested a buoyancy based weight force compensation method which will be presented here. Additionally, results of LFV measurements at non-symmetric fluid profiles will be shown. By that an evaluation of the feasibility of this measurement principle for disturbed fluid profiles that are relevant for developing the LFV for weakly conducting fluids towards industrial applications can be made. Additionally a prospective setup for using the LFV for molten salt flows will be explained.

  12. Two-phase flow cell for chemiluminescence and bioluminescence measurements

    SciTech Connect

    Mullin, J.L.; Seitz, W.R.

    1984-01-01

    A new approach to two-phase CL (chemiluminescence) measurements is reported. A magnetically stirred reagent phase is separated from the analyte phase by a dialysis membrane so that only smaller molecules can go from one phase to the other. The system is designed so that the analyte phase flows through a spiral groove on an aluminum block that is flush against the dialysis membrane. As solution flows through the spiral grove, analyte diffuses into the reagent phase where it reacts to produce light. A simple model is developed to predict how this system will behave. Experimentally, the system is evaluated by using the luminol reaction catalyzed by peroxidase, the firefly reaction, and the bacterial bioluminescence reaction. 10 references, 4 tables, 6 figures.

  13. Measurement of Flow Patterns and Dispersion in the Human Airways

    NASA Astrophysics Data System (ADS)

    Fresconi, Frank E.; Prasad, Ajay K.

    2006-03-01

    A detailed knowledge of the flow and dispersion within the human respiratory tract is desirable for numerous reasons. Both risk assessments of exposure to toxic particles in the environment and the design of medical delivery systems targeting both lung-specific conditions (asthma, cystic fibrosis, and chronic obstructive pulmonary disease (COPD)) and system-wide ailments (diabetes, cancer, hormone replacement) would profit from such an understanding. The present work features experimental efforts aimed at elucidating the fluid mechanics of the lung. Particle image velocimetry (PIV) and laser induced fluorescence (LIF) measurements of oscillatory flows were undertaken in anatomically accurate models (single and multi-generational) of the conductive region of the lung. PIV results captured primary and secondary velocity fields. LIF was used to determine the amount of convective dispersion across an individual generation of the lung.

  14. Two-phase flow measurements of a spray in a turbulent flow

    NASA Technical Reports Server (NTRS)

    Rudoff, R. C.; Houser, M. J.; Bachalo, W. D.

    1987-01-01

    The dynamics of spray drop interaction with a turbulent coflowing air stream were investigated using a Phase Doppler Particle Analyzer that determines both drop size and velocity. Detailed measurements obtained included spray drop size, axial and radial velocity, angle of trajectory, drop Reynolds number, and size-velocity correlations. The gas-phase flow field was also ascertained via the behavior of the smallest drops. Also investigated were the drag coefficients of droplets in a turbulent air cross flow for both monodispersions and polydispersions. Most notable aspects of the coflow included the effect of air streams with velocities significantly different from the spray sheet. Local changes in number density were produced as a result of lateral convection and streamwise accelerations and decelerations of various drop size classes. The complexity of the spray field interaction illustrated by this data effectively describes the development of the spray due to the influence of the airflow. The droplet drag measurements showed similar behavior for monodispersed and polydispersed flows and similar trends to previously obtained data. The measurements also pointed out further studies which would assist in creating an improved drag law for polydispersed drops in a turbulent environment.

  15. Novel Sensors For Measuring Fuel Flow And Level

    NASA Astrophysics Data System (ADS)

    Goodyer, E. N.

    1989-03-01

    This presentation will discuss a novel sensing method for measuring fuel flow which was developed for the Ford Motor Co by Sira Ltd. The fuel flow sensor uses an optical technique based on detecting light scattered from particles carried in the flowing fuel. Two off axis light sources illuminate the fuel flow region. As particles move with the fuel some light is scattered normal to the fuel flow direction. The scattered light is focused onto a course beam splitter which then directs the light onto two matched detectors. The course beam splitter has 5 linear reflecting grooves per mm each with an included angle of 1351. As a particle that is smaller than the groove width moves across the field of view the effect is to focus scattered light from the particle alternately onto each of the two detectors. Each detector therefore receives optical modulation which is in antiphase to that received by the other detector. The difference of the two detector signals is then used. Also presented will be a new design for an optically based steering wheel position. The sensor is now in full scale production and is manufactured by First Inertia Switch Ltd. An assembly consisting of a number of parallel light guides, each 0.25mm wide, views the light reflected from a black and white striped tape that is stuck to the steering column. The signals from the detectors that are mounted remotely at the end of the light guides are interpreted by a PLA device to give rotational information. The sensor offers a higher resolution than traditional similar sensors while maintaining a low manufacturing cost.

  16. Field Measurements of the 1983 Royal Gardens Lava Flows, Kilauea Volcano, and 1984 Mauna Loa Lava Flow, Hawaii

    NASA Technical Reports Server (NTRS)

    Fink, J.; Zimbelman, J.

    1985-01-01

    Theoretical models used in the remote determination of lava flow rheology and compositions rely on estimates of such geometric and flow parameters as volume flow rates, levee heights, and channel dimensions, as well as morphologic and structural patterns on the flow surfaces. Quantitative measures of these variables are difficult to obtain, even under optimum conditions. Detailed topographic profiles across several Hawaiian lava flows that were carefully monitored by the U.S. Geological Survey during their emplacement in 1983 were surveyed in order to test various flow emplacement models. Twenty two accurate channel cross sections were constructed by combining these profiles with digitized pre-flow topographic measurements. Levee heights, shear zone widths, and flow depths could then be read directly from the cross sections and input into the models. The profiles were also compared with ones constructed for some Martian lava flows.

  17. Extensional bundle waveguide techniques for measuring flow of hot fluids.

    PubMed

    Lynnworth, Lawrence C; Liu, Yi; Umina, John A

    2005-04-01

    A bundle of acoustically slender metal rods, each thin compared to wavelength, tightly packed within a sheath, and welded closed at each end, provides a dispersion-free waveguide assembly that acts as a thermal buffer between a transducer and the hot fluid medium the flow of which is to be measured. Gas and steam flow applications have ranged up to 600 degrees C. Liquid applications have ranged from cryogenic (-160 degrees C) to 500 degrees C and include intermittent two-phase flows. The individual rods comprising the bundle usually are approximately one millimeter in diameter. The sheath, made of a pipe or tube, typically has an outside diameter of 12.7 to about 33 mm and usually is about 300 mm long. Materials for the sheath and bundle are selected to satisfy requirements of compatibility with the fluid as well as for acoustic properties. Corrosion-resistant alloys such as 316SS and titanium are commonly used. The buffers are used with transducers that are metal-encapsulated and certified for use in hazardous areas. They operate at a frequency in the range of 0.1 to 1 MHz. The radiating end of the buffer is usually flat and perpendicular to the buffer's main axis. In some cases the end of the buffer is stepped or angled. Angling the radiating faces at approximately 2 degrees to overcome beam drift at Mach 0.1 recently contributed to solving a high-temperature high-velocity flow measurement problem. The temperature in this situation was 300 degrees C, and the gas molecular weight was about 95, with pressure 0.9 to 1.1 bar. PMID:16060500

  18. PIV measurement of flow around an arbitrarily moving body

    NASA Astrophysics Data System (ADS)

    Jeon, Young Jin; Sung, Hyung Jin

    2010-11-01

    PIV image processing methods for measuring flow velocities around an arbitrarily moving body are proposed. A contour-texture analysis based on user-defined textons is applied to determine the arbitrarily moving interface in the 2D PIV. After the interface tracking procedure is performed, the particle images near the interface are transformed into Cartesian coordinates that are related to the distance from the interface. This transformed image always has a straight interface, so the interrogation windows can easily be arranged at certain distances from the interface. Accurate measurements near the interface can then be achieved by applying the window deformation algorithm in concert with PIV/IG. For a tomographic 3D PIV, a volume reconstruction technique from four views is applied to obtain a three-dimensional shape of the interface. Particle motion analysis is made by the MTE MART algorithm. Quantitative evaluations of this method are performed to computer-generated images and actual PIV measurements.

  19. PIV measurement of flow around an arbitrarily moving body

    NASA Astrophysics Data System (ADS)

    Jeon, Young Jin; Sung, Hyung Jin

    2011-04-01

    This paper presents a PIV (particle image velocimetry) image processing method for measuring flow velocities around an arbitrarily moving body. This image processing technique uses a contour-texture analysis based on user-defined textons to determine the arbitrarily moving interface in the particle images. After the interface tracking procedure is performed, the particle images near the interface are transformed into Cartesian coordinates that are related to the distance from the interface. This transformed image always has a straight interface, so the interrogation windows can easily be arranged at certain distances from the interface. Accurate measurements near the interface can then be achieved by applying the window deformation algorithm in concert with PIV/IG (interface gradiometry). The displacement of each window is evaluated by using the window deformation algorithm and was found to result in acceptable errors except for the border windows. Quantitative evaluations of this method were performed by applying it to computer-generated images and actual PIV measurements.

  20. Flow cytomeric measurement of DNA and incorporated nucleoside analogs

    DOEpatents

    Dolbeare, Frank A.; Gray, Joe W.

    1989-01-01

    A method is provided for simultaneously measuring total cellular DNA and incorporated nucleoside analog. The method entails altering the cellular DNA of cells grown in the presence of a nucleoside analog so that single stranded and double stranded portions are present. Separate stains are used against the two portions. An immunochemical stain is used against the single stranded portion to provide a measure of incorporated nucleoside analog, and a double strand DNA-specific stain is used against the double stranded portion to simultaneously provide a measure of total cellular DNA. The method permits rapid flow cytometric analysis of cell populations, rapid identification of cycling and noncycling subpopulations, and determination of the efficacy of S phase cytotoxic anticancer agents.

  1. Skin friction measurements in high temperature high speed flows

    NASA Technical Reports Server (NTRS)

    Schetz, J. A.; Diller, Thomas E.; Wicks, A. L.

    1992-01-01

    An experimental investigation was conducted to measure skin friction along the chamber walls of supersonic combustors. A direct force measurement device was used to simultaneously measure an axial and transverse component of the small tangential shear force passing over a non-intrusive floating element. The floating head is mounted to a stiff cantilever beam arrangement with deflection due to the flow on the order of 0.00254 mm (0.0001 in.). This allowed the instrument to be a non-nulling type. A second gauge was designed with active cooling of the floating sensor head to eliminate non-uniform temperature effects between the sensor head and the surrounding wall. Samples of measurements made in combustor test facilities at NASA Langley Research Center and at the General Applied Science Laboratory (GASL) are presented. Skin friction coefficients between 0.001 - 0.005 were measured dependent on the facility and measurement location. Analysis of the measurement uncertainties indicate an accuracy to within +/- 10-15 percent of the streamwise component.

  2. Global vegetation phenology from Moderate Resolution Imaging Spectroradiometer (MODIS): Evaluation of global patterns and comparison with in situ measurements

    NASA Astrophysics Data System (ADS)

    Zhang, Xiaoyang; Friedl, Mark A.; Schaaf, Crystal B.

    2006-12-01

    In the last two decades the availability of global remote sensing data sets has provided a new means of studying global patterns and dynamics in vegetation. The vast majority of previous work in this domain has used data from the Advanced Very High Resolution Radiometer, which until recently was the primary source of global land remote sensing data. In recent years, however, a number of new remote sensing data sources have become available that have significantly improved the capability of remote sensing to monitor global ecosystem dynamics. In this paper, we describe recent results using data from NASA's Moderate Resolution Imaging Spectroradiometer to study global vegetation phenology. Using a novel new method based on fitting piecewise logistic models to time series data from MODIS, key transition dates in the annual cycle(s) of vegetation growth can be estimated in an ecologically realistic fashion. Using this method we have produced global maps of seven phenological metrics at 1-km spatial resolution for all ecosystems exhibiting identifiable annual phenologies. These metrics include the date of year for (1) the onset of greenness increase (greenup), (2) the onset of greenness maximum (maturity), (3) the onset of greenness decrease (senescence), and (4) the onset of greenness minimum (dormancy). The three remaining metrics are the growing season minimum, maximum, and summation of the enhanced vegetation index derived from MODIS. Comparison of vegetation phenology retrieved from MODIS with in situ measurements shows that these metrics provide realistic estimates of the four transition dates identified above. More generally, the spatial distribution of phenological metrics estimated from MODIS data is qualitatively realistic, and exhibits strong correspondence with temperature patterns in mid- and high-latitude climates, with rainfall seasonality in seasonally dry climates, and with cropping patterns in agricultural areas.

  3. Response of Sap-Flow Measurements on Environmental Forcings

    NASA Astrophysics Data System (ADS)

    Howe, J. A.; Dragoni, D.; Schmid, H.

    2005-05-01

    The exchange of water between the atmosphere and biosphere is an important determinant of climate and the productivity of vegetation. Both evaporation and transpiration involve substantial amounts of energy exchange at the interface of the biosphere and atmosphere. Knowing how transpiration changes throughout the seasonal and diurnal cycles can help increase the understanding of how a forest reacts to changes in the biosphere and atmosphere. A common way to estimate transpiration is by measuring the sap flowing through the living tissues of trees. A study was conducted at Morgan-Monroe State Forest, a mixed deciduous forest in south central Indiana (USA), to investigate how sap flow in trees responds to changes in meteorological and environmental conditions. The heat -dissipation technique was used to estimate sap velocities from two Big Tooth Aspen (Populus grandidentata) and two Tulip Poplars (Liriodendron tulipifera). Sap velocity patterns (normalized by a reference potential evapo-transpiration) were directly compared with meteorological and ecological measurements, such as vapor pressure deficits, photosynthetic active radiation (PAR), rain fall, and soil moisture content. In this study, we also investigated the uncertainties and problems that arise in using the heat dissipation technique to extrapolate the single-tree measurements to the forest scale.

  4. Biochemical oxygen demand measurement by mediator method in flow system.

    PubMed

    Liu, Ling; Bai, Lu; Yu, Dengbin; Zhai, Junfeng; Dong, Shaojun

    2015-06-01

    Using mediator as electron acceptor for biochemical oxygen demand (BOD) measurement was developed in the last decade (BODMed). However, until now, no BOD(Med) in a flow system has been reported. This work for the first time describes a flow system of BOD(Med) method (BOD(Med)-FS) by using potassium ferricyanide as mediator and carbon fiber felt as substrate material for microbial immobilization. The system can determine the BOD value within 30 min and possesses a wider analytical linear range for measuring glucose-glutamic acid (GGA) standard solution from 2 up to 200 mg L(-1) without the need of dilution. The analytical performance of the BOD(Med)-FS is comparable or better than that of the previously reported BOD(Med) method, especially its superior long-term stability up to 2 months under continuous operation. Moreover, the BOD(Med)-FS has same determination accuracy with the conventional BOD5 method by measuring real samples from a local wastewater treatment plant (WWTP). PMID:25863368

  5. Mixing evaluation using an entropic measure in Dean flow micromixers

    NASA Astrophysics Data System (ADS)

    Fodor, Petru; Vyhnalek, Brian; Kaufman, Miron

    2012-10-01

    Promoting mixing in fluid systems at low Reynolds number, remains one of the problems of interest in the development of microreactors. In the laminar flow regime characteristic to these type of systems the mixing between different species needed for chemical reactions relies on diffusion, which is relatively slow. In order to circumvent this problem various methodologies exploiting appropriately chosen geometries or relying on external forces such as magnetic, electrokinetic, ultrasonic ones are used to either increase the interface between the chemical components and/or induce chaotic advection within the fluid stream. In this work we investigate computationally the use of curved channels at Reynolds numbers from 25 to 900, in which the centrifugal forces, experienced by the fluid as it travels along a curved trajectory, induce counter-rotating flows (Dean Vortices). The presence of these transversal flows promotes the mixing of chemical species which are introduced in the system at different position across the cross section of the channel. The mixing efficiency is evaluated using the Shannon entropy. We have found this measure to be useful in understanding mixing in the staggered herringbone mixer [Petru S. Fodor and Miron Kaufman, Modern Physics Letters B 25, 1111 (2011)].

  6. Device for accurately measuring mass flow of gases

    DOEpatents

    Hylton, James O.; Remenyik, Carl J.

    1994-01-01

    A device for measuring mass flow of gases which utilizes a substantially buoyant pressure vessel suspended within a fluid/liquid in an enclosure. The pressure vessel is connected to a weighing device for continuously determining weight change of the vessel as a function of the amount of gas within the pressure vessel. In the preferred embodiment, this pressure vessel is formed from inner and outer right circular cylindrical hulls, with a volume between the hulls being vented to the atmosphere external the enclosure. The fluid/liquid, normally in the form of water typically with an added detergent, is contained within an enclosure with the fluid/liquid being at a level such that the pressure vessel is suspended beneath this level but above a bottom of the enclosure. The buoyant pressure vessel can be interconnected with selected valves to an auxiliary pressure vessel so that initial flow can be established to or from the auxiliary pressure vessel prior to flow to or from the buoyant pressure vessel.

  7. Device for accurately measuring mass flow of gases

    DOEpatents

    Hylton, J.O.; Remenyik, C.J.

    1994-08-09

    A device for measuring mass flow of gases which utilizes a substantially buoyant pressure vessel suspended within a fluid/liquid in an enclosure is disclosed. The pressure vessel is connected to a weighing device for continuously determining weight change of the vessel as a function of the amount of gas within the pressure vessel. In the preferred embodiment, this pressure vessel is formed from inner and outer right circular cylindrical hulls, with a volume between the hulls being vented to the atmosphere external the enclosure. The fluid/liquid, normally in the form of water typically with an added detergent, is contained within an enclosure with the fluid/liquid being at a level such that the pressure vessel is suspended beneath this level but above a bottom of the enclosure. The buoyant pressure vessel can be interconnected with selected valves to an auxiliary pressure vessel so that initial flow can be established to or from the auxiliary pressure vessel prior to flow to or from the buoyant pressure vessel. 5 figs.

  8. Validity of the New Lifestyles NL-1000 Accelerometer for Measuring Time Spent in Moderate-to-Vigorous Physical Activity in School Settings

    ERIC Educational Resources Information Center

    McMinn, David; Rowe, David A.; Stark, Michelle; Nicol, Louise

    2010-01-01

    Current interest in promoting physical activity in the school environment necessitates an inexpensive, accurate method of measuring physical activity in such settings. Additionally, it is recognized that physical activity must be of at least moderate intensity in order to yield substantial health benefits. The purpose of the study, therefore, was…

  9. 21 CFR 876.1800 - Urine flow or volume measuring system.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Urine flow or volume measuring system. 876.1800... volume measuring system. (a) Identification. A urine flow or volume measuring system is a device that measures directly or indirectly the volume or flow of urine from a patient, either during the course...

  10. 21 CFR 876.1800 - Urine flow or volume measuring system.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Urine flow or volume measuring system. 876.1800... volume measuring system. (a) Identification. A urine flow or volume measuring system is a device that measures directly or indirectly the volume or flow of urine from a patient, either during the course...

  11. 21 CFR 876.1800 - Urine flow or volume measuring system.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Urine flow or volume measuring system. 876.1800... volume measuring system. (a) Identification. A urine flow or volume measuring system is a device that measures directly or indirectly the volume or flow of urine from a patient, either during the course...

  12. 21 CFR 876.1800 - Urine flow or volume measuring system.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Urine flow or volume measuring system. 876.1800... volume measuring system. (a) Identification. A urine flow or volume measuring system is a device that measures directly or indirectly the volume or flow of urine from a patient, either during the course...

  13. 21 CFR 876.1800 - Urine flow or volume measuring system.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Urine flow or volume measuring system. 876.1800... volume measuring system. (a) Identification. A urine flow or volume measuring system is a device that measures directly or indirectly the volume or flow of urine from a patient, either during the course...

  14. Device and method for measuring multi-phase fluid flow in a conduit using an elbow flow meter

    DOEpatents

    Ortiz, Marcos G.; Boucher, Timothy J.

    1997-01-01

    A system for measuring fluid flow in a conduit. The system utilizes pressure transducers disposed generally in line upstream and downstream of the flow of fluid in a bend in the conduit. Data from the pressure transducers is transmitted to a microprocessor or computer. The pressure differential measured by the pressure transducers is then used to calculate the fluid flow rate in the conduit. Control signals may then be generated by the microprocessor or computer to control flow, total fluid dispersed, (in, for example, an irrigation system), area of dispersal or other desired effect based on the fluid flow in the conduit.

  15. Device and method for measuring multi-phase fluid flow in a conduit using an elbow flow meter

    DOEpatents

    Ortiz, M.G.; Boucher, T.J.

    1997-06-24

    A system is described for measuring fluid flow in a conduit. The system utilizes pressure transducers disposed generally in line upstream and downstream of the flow of fluid in a bend in the conduit. Data from the pressure transducers is transmitted to a microprocessor or computer. The pressure differential measured by the pressure transducers is then used to calculate the fluid flow rate in the conduit. Control signals may then be generated by the microprocessor or computer to control flow, total fluid dispersed, (in, for example, an irrigation system), area of dispersal or other desired effect based on the fluid flow in the conduit. 2 figs.

  16. Correlation of clinical and angiographic findings in brain ischemia with regional cerebral blood flow measured by the xenon inhalation technique

    SciTech Connect

    Awad, I.; Little, J.R.; Furlan, A.J.; Weinstein, M.

    1982-07-01

    Eighty-eight patients with brain ischemia underwent cerebral angiography and measurement of regional cerebral blood flow (rCBF) after /sup 133/Xe inhalation. A fast compartment flow rate and an initial slope index were computed for each detector and for each hemisphere. The clinical presentation, angiographic findings, and rCBF results were then examined for significant correlations. Patients with hemispheric infarction most frequently showed bilateral diffusely decreased rCBF. In patients with transient ischemic attacks, no specific pattern emerged. Patients with unilateral internal carotid artery occlusion frequently hd bilateral diffusely decreased rCBF. Patients with severe internal carotid artery stenosis were more likely to show decreased rCBF than were patients with mild or moderate stenosis. The initial slope index seemed to be a more sensitive indicator of brain ischemia than the fast compartment flow rate. The possible pathophysiological significance and relationship to patient management of the various rCBF patterns are discussed.

  17. Measurement and modelling of sap flow in maize plants

    NASA Astrophysics Data System (ADS)

    Heinlein, Florian; Biernath, Christian; Hoffmann, Peter; Klein, Christian; Thieme, Christoph; Priesack, Eckart

    2014-05-01

    Climate change as well as the changing composition of the atmosphere will have an impact on future yield of agricultural plants. In order to better estimate these impacts new, mechanistic plant growth models are needed. These models should be able to dynamically reproduce the plants' reactions to modified climate state variables like temperature, atmospheric CO2-concentration and water availability. In particular, to better describe the crop response to more strongly changing water availability the simulation of plant-internal water and solute transport processes in xylem and phloem needs to be improved. Our existing water transport model consists of two coupled 1-D Richards equations to calculate water transport in the soil and in the plants. This model has already been successfully applied to single Fagus sylvatica L. trees. At present it is adapted to agricultural plants such as maize. To simulate the water transport within the plants a representation of the flow paths, i.e. the plant architecture, is required. Aboveground plant structures are obtained from terrestrial laser scan (TLS) measurements at different development stages. These TLSs have been executed at the lysimeter facilities of Helmholtz Zentrum München and at the TERENO (Terrestrial Environmental Observatories) research farm Scheyern. Additionally, an L-system model is used to simulate aboveground and belowground plant architectures. In a further step, the quality of the explicit water flow model has to be tested using measurements. The Heat-Ratio-Method has been employed to directly measure sap flow in larger maize plants during a two-months-period in summer 2013 with a resolution of 10 minutes and thus, the plants' transpiration can be assessed. Water losses from the soil are determined by measuring the weight of lysimeters. From this evapotranspiration can be calculated. Transpiration and evapotranspiration are also simulated by application of the modelling system Expert-N. This framework

  18. Flow cytometric measurement of pollutant stresses on algal cells

    SciTech Connect

    Berglund, D.L.; Eversman, S.

    1988-03-01

    The lichen Usnea fulvoreagens (Raes). Raes. was treated with four pH levels (5.5, 4.5, 3.5, and 2.5) of simulated acid rain (sulfuric acid, nitric acid, and a 1:1 combination of both) and automobile exhaust. The samples were dissociated and analyzed by a Becton-Dickinson FACS 440 flow cytometer. Analyses included measurement of chlorophyll autofluorescence and fluorescence due to uptake of fluorescein diacetate (FDA) and calcofluor white M2R (CFW). Cell parameters measured were esterase activity (FDA), membrane permeability (FDA, CFW), and intracellular pH (FDA). Mean fluorescence intensity from FDA staining and numbers of events were incorporated with autofluorescence information to produce a stress index of relative cell stress. Results indicated that highly stressed samples (lower pH treatments and greater exposure to exhaust) exhibited a low stress index of FDA fluorescence.Au

  19. Measurement of two-phase flow momentum with force transducers

    SciTech Connect

    Hardy, J.E.; Smith, J.E.

    1990-01-01

    Two strain-gage-based drag transducers were developed to measure two-phase flow in simulated pressurized water reactor (PWR) test facilities. One transducer, a drag body (DB), was designed to measure the bidirectional average momentum flux passing through an end box. The second drag sensor, a break through detector (BTD), was designed to sense liquid downflow from the upper plenum to the core region. After prototype sensors passed numerous acceptance tests, transducers were fabricated and installed in two experimental test facilities, one in Japan and one in West Germany. High-quality data were extracted from both the DBs and BTDs for a variety of loss-of-coolant accident (LOCA) scenarios. The information collected from these sensors has added to the understanding of the thermohydraulic phenomena that occur during the refill/reflood stage of a LOCA in a PWR. 9 refs., 15 figs.

  20. Optical Spectroscopic Measurements of the Z Machine Power Flow Region

    NASA Astrophysics Data System (ADS)

    Gomez, Matthew; Gilgenbach, Ron; Cuneo, Mike; McBride, Ryan; Rochau, Greg; Jones, Brent; Ampleford, Dave; Sinars, Dan; Bailey, Jim; Stygar, Bill; Savage, Mark; Jones, Michael; Edens, Aaron; Lopez, Mike; Stambulchik, E.; Maron, Y.; Rose, Dave; Welch, Dale

    2012-10-01

    Pulsed power machines typically utilize vacuum transmission lines to deliver energy to the load. Large-scale drivers often employ several parallel transmission lines to reduce inductance. Post-hole convolutes can be used to combine the current from the transmission lines at the load. Losses in the post-hole convolute and vacuum transmission lines on the Z-machine are as high as 20% of the peak current. Spectroscopic measurements of the plasma that forms on the power flow surfaces are underway. A second visible spectroscopy system has been added to the Z diagnostic suite, which allows symmetry measurements of the plasma formation. Investigations of the convolute plasma origin and propagation are ongoing. *Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

  1. Phased-Array Measurements of Single Flow Hot Jets

    NASA Technical Reports Server (NTRS)

    Bridges, James; Lee, Sang Soo

    2005-01-01

    A 16 microphone phased-array system has been successfully applied to measure jet noise source distributions. In this study, a round convergent nozzle was tested at various hot and cold flow conditions: acoustic Mach numbers are between 0.35 and 1.6 and static temperature ratios are varied from cold to 2.7. The classical beamforming method was applied on narrowband frequencies. From the measured source distributions locations of peak strength were tracked and found to be very consistent between adjacent narrowband frequencies. In low speed heated and unheated jets, the peak source locations vary smoothly from the nozzle exit to downstream as the frequency is decreased. When the static temperature ratio was kept constant, the peak source position moved downstream with increasing acoustic Mach number for the Strouhal numbers smaller than about 1.5. It was also noted that the peak source locations of low frequencies occur farther downstream than the end of potential core.

  2. Thermal and flow measurements of continuous cryogenic spray cooling.

    PubMed

    Hsieh, Shou-Shing; Tsai, Huang-Hsiu

    2006-07-01

    The performance of single sprays for high heat flux cooling using R-134a was studied. The heat flux and heat transfer coefficient at the surface of a sprayed jet based on measurements of steady-state temperature gradients on a thin copper plate during continuous spraying. Meanwhile, the spray droplets flow characteristics was also quantified through laser doppler velocimetry (LDV) measurements to obtain the local velocity distributions. The effects of mass flow rate and average droplet velocity, and spray exit-to-target distance on the surface heat flux including the corresponding critical heat flux (CHF) were explored through three different nozzle diameters of 0.2, 0.3, and 0.4 mm. Finally, the effective use of the fluid being delivered based on the cooling efficiency and cooling effectiveness was also examined. The relationship between CHF and nozzle performance in terms of cooling efficiency and cooling effectiveness was found. The heat transfer removal rate can reach up to 140 W/cm(2) for the present nozzle size of d (j)=0.2 and 0.3 mm, which may enhance the current cryogen spray cooling (CSC) technique that assists laser therapy of dermatoses. PMID:16598481

  3. Measurements of Reynolds stress profiles in unstratified tidal flow

    USGS Publications Warehouse

    Stacey, M.T.; Monismith, Stephen G.; Burau, J.R.

    1999-01-01

    In this paper we present a method for measuring profiles of turbulence quantities using a broadband acoustic doppler current profiler (ADCP). The method follows previous work on the continental shelf and extends the analysis to develop estimates of the errors associated with the estimation methods. ADCP data was collected in an unstratified channel and the results of the analysis are compared to theory. This comparison shows that the method provides an estimate of the Reynolds stresses, which is unbiased by Doppler noise, and an estimate of the turbulent kinetic energy (TKE) which is biased by an amount proportional to the Doppler noise. The noise in each of these quantities as well as the bias in the TKE match well with the theoretical values produced by the error analysis. The quantification of profiles of Reynolds stresses simultaneous with the measurement of mean velocity profiles allows for extensive analysis of the turbulence of the flow. In this paper, we examine the relation between the turbulence and the mean flow through the calculation of u*, the friction velocity, and Cd, the coefficient of drag. Finally, we calculate quantities of particular interest in turbulence modeling and analysis, the characteristic lengthscales, including a lengthscale which represents the stream-wise scale of the eddies which dominate the Reynolds stresses. Copyright 1999 by the American Geophysical Union.

  4. Flow mediated endothelium function: advantages of an automatic measuring technique

    NASA Astrophysics Data System (ADS)

    Maio, Yamila; Casciaro, Mariano E.; José Urcola y, Maria; Craiem, Damian

    2007-11-01

    The objective of this work is to show the advantages of a non invasive automated method for measuring flow mediated dilation (FMD) in the forearm. This dilation takes place in answer to a shear tension generated by the increase of blood flow, sensed by the endothelium, after the liberation of an occlusion sustained in the time. The method consists of three stages: the continuous acquisition of images of the brachial artery using ultrasound techniques, the pulse to pulse measurement of the vessel's diameter by means of a border detection algorithm, and the later analysis of the results. By means of this technique one cannot only obtain the maximum dilation percentage (FMD%), but a continuous diameter curve that allows to evaluate other relevant aspects such as dilation speed, dilation sustain in time and general maneuver performance. The simplicity of this method, robustness of the technique and accessibility of the required elements makes it a viable alternative of great clinical value for diagnosis in the early detection of numerous cardiovascular pathologies.

  5. Measurement and Characterization of Apoptosis by Flow Cytometry.

    PubMed

    Telford, William; Tamul, Karen; Bradford, Jolene

    2016-01-01

    Apoptosis is an important mechanism in cell biology, playing a critical regulatory role in virtually every organ system. It has been particularly well characterized in the immune system, with roles ranging from immature immune cell development and selection to down-regulation of the mature immune response. Apoptosis is also the primary mechanism of action of anti-cancer drugs. Flow cytometry has been the method of choice for analyzing apoptosis in suspension cells for more than 25 years. Numerous assays have been devised to measure both the earliest and latest steps in the apoptotic process, from the earliest signal-transduction events to the late morphological changes in cell shape and granularity, proteolysis, and chromatin condensation. These assays are particularly powerful when combined into multicolor assays determining several apoptotic characteristics simultaneously. The multiparametric nature of flow cytometry makes this technology particularly suited to measuring apoptosis. In this unit, we will describe the four main techniques for analyzing caspase activity in apoptotic cells, combined with annexin V and cell permeability analysis. These relatively simple multiparametric assays are powerful techniques for assessing cell death. © 2016 by John Wiley & Sons, Inc. PMID:27367289

  6. Measurement and Computation of Supersonic Flow in a Lobed Diffuser-Mixer for Trapped Vortex Combustors

    NASA Technical Reports Server (NTRS)

    Brankovic, Andreja; Ryder, Robert C., Jr.; Hendricks, Robert C.; Liu, Nan-Suey; Gallagher, John R.; Shouse, Dale T.; Roquemore, W. Melvyn; Cooper, Clayton S.; Burrus, David L.; Hendricks, John A.

    2002-01-01

    The trapped vortex combustor (TVC) pioneered by Air Force Research Laboratories (AFRL) is under consideration as an alternative to conventional gas turbine combustors. The TVC has demonstrated excellent operational characteristics such as high combustion efficiency, low NO(x) emissions, effective flame stabilization, excellent high-altitude relight capability, and operation in the lean-burn or rich burn-quick quench-lean burn (RQL) modes of combustion. It also has excellent potential for lowering the engine combustor weight. This performance at low to moderate combustor mach numbers has stimulated interest in its ability to operate at higher combustion mach number, and for aerospace, this implies potentially higher flight mach numbers. To this end, a lobed diffuser-mixer that enhances the fuel-air mixing in the TVC combustor core was designed and evaluated, with special attention paid to the potential shock system entering the combustor core. For the present investigation, the lobed diffuser-mixer combustor rig is in a full annular configuration featuring sixfold symmetry among the lobes, symmetry within each lobe, and plain parallel, symmetric incident flow. During hardware cold-flow testing, significant discrepancies were found between computed and measured values for the pitot-probe-averaged static pressure profiles at the lobe exit plane. Computational fluid dynamics (CFD) simulations were initiated to determine whether the static pressure probe was causing high local flow-field disturbances in the supersonic flow exiting the diffuser-mixer and whether shock wave impingement on the pitot probe tip, pressure ports, or surface was the cause of the discrepancies. Simulations were performed with and without the pitot probe present in the modeling. A comparison of static pressure profiles without the probe showed that static pressure was off by nearly a factor of 2 over much of the radial profile, even when taking into account potential axial displacement of the

  7. Debris flow cartography using differential GNSS and Theodolite measurements

    NASA Astrophysics Data System (ADS)

    Khazaradze, Giorgi; Guinau, Marta; Calvet, Jaume; Furdada, Gloria; Victoriano, Ane; Génova, Mar; Suriñach, Emma

    2016-04-01

    The presented results form part of a CHARMA project, which pursues a broad objective of reducing damage caused by uncontrolled mass movements, such as rockfalls, snow avalanches and debris flows. Ultimate goal of the project is to contribute towards the establishment of new scientific knowledge and tools that can help in the design and creation of early warning systems. Here we present the specific results that deal with the application of differential GNSS and classical geodetic (e.g. theodolite) methods for mapping debris and torrential flows. Specifically, we investigate the Portainé stream located in the Pallars Sobirà region of Catalonia (Spain), in the eastern Pyrenees. In the last decade more than ten debris-flow type phenomena have affected the region, causing considerable economic losses. Since early 2014, we have conducted several field campaigns within the study area, where we have employed a multi-disciplinary approach, consisting of geomorphological, dendro-chronological and geodetic methods, in order to map the river bed and reconstruct the history of the extreme flooding and debris flow events. Geodetic studies included several approaches, using the classical and satellite based methods. The former consisted of angle and distance measurements between the Geodolite 502 total station and the reflecting prisms placed on top of the control points located within the riverbed. These type of measurements are precise, although present several disadvantages such as the lack of absolute coordinates that makes the geo-referencing difficult, as well as a relatively time-consuming process that involves two persons. For this reason, we have also measured the same control points using the differential GNSS system, in order to evaluate the feasibility of replacing the total station measurements with the GNSS. The latter measuring method is fast and can be conducted by one person. However, the fact that the study area is within the riverbed, often below the trees

  8. A comparison of predicted and measured inlet distortion flows in a subsonic axial inlet flow compressor rotor

    NASA Technical Reports Server (NTRS)

    Owen, Albert K.

    1992-01-01

    Detailed flow measurements were taken inside an isolated axial compressor rotor operating subsonically near peak efficiency. These Laser Anemometer measurements were made with two inlet velocity profiles. One profile consisted of an unmodified baseline flow, and the second profile was distorted by placing axisymmetric screens on the hub and shroud well upstream of the rotor. A detailed comparison in the rotor relative reference frame between a Navier-Stokes solver and the measured experimental results showed good agreement between the predicted and measured flows. A primary flow is defined in the rotor and deviations and the computed predictions is made to assess the development of a passage vortex due to the distortion of the inlet flow. Computer predictions indicate that a distorted inlet profile has a minimal effect on the development of the flow in the rotor passage and the resulting passage vortex.

  9. Measuring Black Smoker Fluid Flow Rates Using Image Correlation Velocimetry

    NASA Astrophysics Data System (ADS)

    Crone, T. J.; Wilcock, W. S.; McDuff, R. E.

    2006-12-01

    Motivated by a desire to find non-invasive methods for obtaining time-series measurements of fluid flow rates through mid-ocean ridge black smokers, we are developing an image-based velocimetry technique that will provide this information through the analysis of video sequences showing the turbulent structures of black smoker effluent jets. Our ultimate goal is to develop an autonomous seafloor instrument suitable for use with a cabled seafloor observatory that can provide extended time-series measurements of black smoker discharge rates with little user intervention. The method we are developing is based on the two-dimensional cross-correlation of an array of overlapping subimages from two sequential image frames within a sequence. For each pair of images this yields a two- dimensional representation of the instantaneous velocity field in the imaged flow. For each video sequence, the set of these "image velocity fields" from all image pairs is temporally averaged to yield a smoothed representation of the time-averaged image flow field. A transformation is then applied to convert the image flow fields into a relative discharge rate. We have developed a computational algorithm to implement this technique and have successfully applied it to video sequences collected in the late 1980s and early 1990s showing the discharge of black smokers in the Main Endeavour field of the Juan de Fuca Ridge over the course of weeks and months. We are able to resolve velocity fields that are qualitatively consistent with those predicted by plume theory from 5 seconds of video (150 image pairs), but it is difficult to calibrate or assess the precision of the technique with field data alone. In order to address these issues, as well as refine the computational algorithm, we have conducted laboratory simulations of black smoker jets with known discharge rates over a range of Reynolds numbers. We have recorded these simulations to obtain video image sequences that are similar to those

  10. Use of small turbine-type flowmeters to measure flow in large pipes

    NASA Technical Reports Server (NTRS)

    Minkin, H. L.; Hobart, H. F.

    1972-01-01

    Measurement of mass flow in large pipes using small turbine-type flowmeters is discussed. Experiments for determining accuracy of flowmeter and applicability to various types of flow measurement are reported. Illustration of turbine flowmeter and calibration curve are included.

  11. A New Method for Flow Rate Measurement in Millimeter-Scale Pipes

    PubMed Central

    Ji, Haifeng; Gao, Xuemin; Wang, Baoliang; Huang, Zhiyao; Li, Haiqing

    2013-01-01

    Combining the Capacitively Coupled Contactless Conductivity Detection (C4D) technique and the principle of cross correlation flow measurement, a new method for flow rate measurement in millimeter-scale pipes was proposed. The research work included two parts. First, a new five-electrode C4D sensor was developed. Second, with two conductivity signals obtained by the developed sensor, the flow rate measurement was implemented by using the principle of cross correlation flow measurement. The experimental results showed that the proposed flow rate measurement method was effective, the developed five-electrode C4D sensor was successful, and the measurement accuracy was satisfactory. In five millimeter-scale pipes with different inner diameters of 0.5, 0.8, 1.8, 3.0 and 3.9 mm respectively, the maximum relative difference of the flow rate measurement between the reference flow rate and the measured flow rate was less than 5%. PMID:23353139

  12. Potential errors in measuring the phase difference between chest flow and mouth flow.

    PubMed

    Mishima, M; Kawakami, K; Sugiura, N; Fukunaga, T; Sakai, N; Hirai, T; Kuno, K

    1993-01-01

    We have previously reported that the phase difference between chest and mouth flows was a useful indicator of obstructive lung disease. In this paper, we calculated the effects of (i) airway reactance, (ii) extrathoracic airway shunt impedance, (iii) heating and humidification of the inspired air, (iv) abdominal gas volume, and (v) respiratory quotient on the measurement of the phase difference between chest flow (Vc) and mouth flow (Vm) using computer simulations. When the airway impedance was approximated as simple airway resistance, the phase difference (theta r) was calculated to be 0.8% less than the phase difference (theta s) calculated from the airway impedance (Za), including airway inertance and shunt compliance, in the normal lung. theta s became larger than theta r when the peripheral resistance increased, but did not exceed 5%. The extrathoracic airway shunt impedance effect did not exceed 0.1%, regardless of the respiratory frequency, airway impedance or thoracic gas volume. The influence of heating and humidification of the inspired air on the phase difference was calculated to be within 5%. The effect of abdominal gas was highly dependent on the abdominal gas volume and the respiratory pattern, but was calculated to be within 5%. The influence of the respiratory quotient was calculated to be negligible. As a result, it was concluded that none of the factors discussed above are an obstacle to the clinical application of this method for the evaluation of pathological changes in obstructive airway disorders. PMID:8280667

  13. Two Phase Flow Measurements by Nuclear Magnetic Resonance (NMR)

    SciTech Connect

    Altobelli, Stephen A; Fukushima, Eiichi

    2006-08-14

    In concentrated suspensions, there is a tendency for the solid phase to migrate from regions of high shear rate to regions of low shear (Leighton & Acrivos, 1987). In the early years that our effort was funded by the DOE Division of Basic Energy Science, quantitative measurement of this process in neutrally buoyant suspensions was a major focus (Abbott, et al., 1991; Altobelli, et al., 1991). Much of this work was used to improve multi-phase numerical models at Sandia National Laboratories. Later, our collaborators at Sandia and the University of New Mexico incorporated body forces into their numerical models of suspension flow (Rao, Mondy, Sun, et al., 2002). We developed experiments that allow us to study flows driven by buoyancy, to characterize these flows in well-known and useful engineering terms (Altobelli and Mondy, 2002) and to begin to explore the less well-understood area of flows with multiple solid phases (Beyea, Altobelli, et al., 2003). We also studied flows that combine the effects of shear and buoyancy, and flows of suspensions made from non-Newtonian liquids (Rao, Mondy, Baer, et al, 2002). We were able to demonstrate the usefulness of proton NMR imaging of liquid phase concentration and velocity and produced quantitative data not obtainable by other methods. Fluids flowing through porous solids are important in geophysics and in chemical processing. NMR techniques have been widely used to study liquid flow in porous media. We pioneered the extension of these studies to gas flows (Koptyug, et al, 2000, 2000, 2001, 2002). This extension allows us to investigate a wider range of Peclet numbers, and to gather data on problems of interest in catalysis. We devised two kinds of NMR experiments for three-phase systems. Both experiments employ two NMR visible phases and one phase that gives no NMR signal. The earlier method depends on the two visible phases differing in a NMR relaxation property. The second method (Beyea, Altobelli, et al., 2003) uses two

  14. Guarded capacitance probes for measuring particle concentration and flow

    DOEpatents

    Louge, M.Y.

    1995-10-17

    Guarded capacitance probe structures are constructed with guard electrodes surrounding one or more sensor electrodes and ground electrodes or grounded surfaces surrounding the guard electrodes. In a one sensor embodiment, the probe utilizes an apertured sensor electrode and the guard electrode both surrounds the sensor electrode and fills the aperture. This embodiment is particularly useful for measuring particle concentration in a fluid suspension contained within a vessel or pipe. The portion of the guard electrode within the aperture of the sensor electrode prevents electric field lines from emanating from the sensor electrode into the fluid suspension and toward infinity. A two sensor embodiment of the probe is useful for measuring flow velocities of fluid suspensions through cross correlation of the outputs generated by each sensor. The relative dimensions of the guard and sensor electrodes are selected to provide the most accurate measurements by confining the electric lines emanating from the sensor electrode or electrodes and terminating on the surrounding grounded surfaces to a small measurement volume of the fluid suspension near the vessel or pipe wall. 14 figs.

  15. Guarded capacitance probes for measuring particle concentration and flow

    DOEpatents

    Louge, M.Y.

    1996-08-13

    Guarded capacitance probe structures are constructed with guard electrodes surrounding one or more sensor electrodes and ground electrodes or grounded surfaces surrounding the guard electrodes. In a one sensor embodiment, the probe utilizes an apertured sensor electrode and the guard electrode both surrounds the sensor electrode and fills the aperture. This embodiment is particularly useful for measuring particle concentration in a fluid suspension contained within a vessel or pipe. The portion of the guard electrode within the aperture of the sensor electrode prevents electric field lines from emanating from the sensor electrode into the fluid suspension and toward infinity. A two sensor embodiment of the probe is useful for measuring flow velocities of fluid suspensions through cross correlation of the outputs generated by each sensor. The relative dimensions of the guard and sensor electrodes are selected to provide the most accurate measurements by confining the electric lines emanating from the sensor electrode or electrodes and terminating on the surrounding grounded surfaces to a small measurement volume of the fluid suspension near the vessel or pipe wall. 14 figs.

  16. Guarded capacitance probes for measuring particle concentration and flow

    DOEpatents

    Louge, Michel Y.

    1995-01-01

    Guarded capacitance probe structures are constructed with guard electrodes surrounding one or more sensor electrodes and ground electrodes or grounded surfaces surrounding the guard electrodes. In a one sensor embodiment, the probe utilizes an apertured sensor electrode and the guard electrode both surrounds the sensor electrode and fills the aperture. This embodiment is particularly useful for measuring particle concentration in a fluid suspension contained within a vessel or pipe. The portion of the guard electrode within the aperture of the sensor electrode prevents electric field lines from emanating from the sensor electrode into the fluid suspension and toward infinity. A two sensor embodiment of the probe is useful for measuring flow velocities of fluid suspensions through cross correlation of the outputs generated by each sensor. The relative dimensions of the guard and sensor electrodes are selected to provide the most accurate measurements by confining the electric lines emanating from the sensor electrode or electrodes and terminating on the surrounding grounded surfaces to a small measurement volume of the fluid suspension near the vessel or pipe wall.

  17. Guarded capacitance probes for measuring particle concentration and flow

    DOEpatents

    Louge, Michel Y.

    1996-01-01

    Guarded capacitance probe structures are constructed with guard electrodes surrounding one or more sensor electrodes and ground electrodes or grounded surfaces surrounding the guard electrodes. In a one sensor embodiment, the probe utilizes an apertured sensor electrode and the guard electrode both surrounds the sensor electrode and fills the aperture. This embodiment is particularly useful for measuring particle concentration in a fluid suspension contained within a vessel or pipe. The portion of the guard electrode within the aperture of the sensor electrode prevents electric field lines from emanating from the sensor electrode into the fluid suspension and toward infinity. A two sensor embodiment of the probe is useful for measuring flow velocities of fluid suspensions through cross correlation of the outputs generated by each sensor. The relative dimensions of the guard and sensor electrodes are selected to provide the most accurate measurements by confining the electric lines emanating from the sensor electrode or electrodes and terminating on the surrounding grounded surfaces to a small measurement volume of the fluid suspension near the vessel or pipe wall.

  18. Ion Flow Measurements from the JOULE Sounding Rocket Mission

    NASA Astrophysics Data System (ADS)

    Sangalli, L.; Knudsen, D.; Pfaff, R.; Burchil, J.; Larsen, M.; Clemmons, J.; Steigies, C.

    2006-12-01

    The JOULE sounding rocket mission was designed to investigate structured Joule dissipation in the auroral ionosphere. JOULE was launched March 27, 2003 from Poker Flat, Alaska, during a substorm. The mission included two instrumented rockets and two chemical release (TMA) rockets. One of the instrumented payloads carried a Suprathermal Ion Imager (SII) that measured 2-D (energy/angle) distributions of the core (0- 8 eV) ion population at a rate of 125 per second. SII measured one component of the ion drift velocitiy perpendicular to the magnetic field and the field-aligned component of the ion drift velocity. We present results showing good agreement between ion drifts measured perpendicular to the geomagnetic field and those inferred from an ěc E×ěc B measurement, with signs of ion demagnetization as the payload reached the upper E region. Also, the SII shows evidence of downward field-aligned ion flows at altitudes of 140-170 km within a region of enhanced auroral precipitation.

  19. Active Flow Control Strategies Using Surface Pressure Measurements

    NASA Technical Reports Server (NTRS)

    Kumar, Vikas; Alvi, Farrukh S.

    2010-01-01

    Evaluate the efficacy of Microjets Can we eliminate/minimize flow separation? Is the flow unsteadiness reduced? Guidelines for an active control Search for an appropriate sensor. Examine for means to develop a flow model for identifying the state of flow over the surface Guidelines toward future development of a Simple and Robust control methodology

  20. Acute Increase in Hepatic Arterial Flow During TIPS Identified by Intravascular Flow Measurements

    SciTech Connect

    Radeleff, Boris Sommer, Christof-Matthias; Heye, Tobias; Lopez-Benitez, Ruben; Sauer, Peter; Schmidt, Jan; Kauczor, Haus-Ulrich; Richter, Goetz Martin

    2009-01-15

    The purpose of this study was to investigate alterations of hepatic arterial flow during transjugular intrahepatic portosystemic stent shunt (TIPS) applying intravascular Doppler sonography. This prospective monocenter study included 25 patients with liver cirrhosis (alcohol induced [n = 19], chronic hepatitis associated [n = 3], primary biliary cirrhosis associated [n = 1], and cryptogenic [n = 2]) successfully treated with TIPS. All patients underwent intravascular hepatic arterial flow measurements during TIPS using an endoluminal flow sensor. The average arterial peak velocity (APV) and the maximum arterial peak velocity (MPV) were registered. Twenty-two patients (88%) showed increased APV, one patient (4%) showed unaffected APV, and two patients (8%) showed decreased APV after TIPS. The average portosystemic pressure gradient decreased significantly, from 22.0 {+-} 5.1 mmHg before TIPS to 11.0 {+-} 4.1 mmHg after TIPS (-50.0%; p < 0.0001). The average APV increased significantly, from 41.9 {+-} 17.8 cm/s before TIPS to 60.7 {+-} 19.0 cm/s after TIPS (+44.9%; p < 0.0001). The average MPV increased significantly, from 90.8 {+-} 31.7 cm/s before TIPS to 112.6 {+-} 34.9 cm/s after TIPS (+24.0%; p = 0.0002). These changes in perfusion set in within seconds after TIPS tract formation in all the patients with increased APV. We conclude that TIPS-induced portosystemic decompression leads to a significant increase in hepatic arterial flow. The changes occurred within seconds, suggesting a reflex-like mechanism.

  1. Monitoring Fluid Flow in Fractured Carbonate Rocks Using Seismic Measurements

    NASA Astrophysics Data System (ADS)

    Li, W.; Pyrak-Nolte, L. J.

    2008-12-01

    The physical properties of carbonate rock are strongly influenced by the rock fabric which depends on the depositional environment, diagenetic and tectonic processes. The most common form of heterogeneity is layering caused by a variation in porosity among layers and within layers. The variation in porosity among layers leads to anisotropic behavior in the hydraulic, mechanical and seismic properties of carbonate rocks. We present the results of a laboratory study to examine the effect of fabric-controlled layering on fluid flow and seismic wave propagation through intact and fractured carbonate rock. Experiments were performed on cubic samples of Austin Chalk Cordova Cream. Samples AC1, AC5 and AC6 are cubic samples that measure 100 mm on edge. The samples were sealed and contained three inlet and three outlet ports for fluid invasion experiments. Two orthogonal seismic arrays were used to record both compressional and shear wave transmission through intact and fractured samples. The arrays used piezoelectric contact transducers with a central frequency 1.0 MHz. Between the two arrays, sixteen sources and sixteen receivers were used. Seismic measurements were made on the samples as a function of stress and during fluid saturation. The location of the invading fluid front as a function of time was monitored by using the peak-to-peak amplitude of the transmitted signals. The front was assumed to be between a source-receiver pair when the signal amplitude decreased by 50% over the initial value. The hydraulic gradient was parallel and perpendicular to the layers for AC5 and AC6, respectively. Sample AC1 was fractured and flow ports were established on the edges of the fracture plane. The weakly directed fabric controlled the rate at which fluid flowed through the samples. From the seismic data on AC6, the fluid first spread vertically along a layer before flowing across the layers. For AC6, it took the fluid two and half hours to flow between the inlet and the outlet

  2. Momentum Flux Measuring Instrument for Neutral and Charged Particle Flows

    NASA Technical Reports Server (NTRS)

    Chavers, Greg; Chang-Diaz, Franklin; Schafer, Charles F. (Technical Monitor)

    2002-01-01

    An instrument to measure the momentum flux (total pressure) of plasma and neutral particle jets onto a surface has been developed. While this instrument was developed for magnetized plasmas, the concept works for non-magnetized plasmas as well. We have measured forces as small as 10(exp -4) Newtons on a surface immersed in the plasma where small forces are due to ionic and neutral particles with kinetic energies on the order of a few eV impacting the surface. This instrument, a force sensor, uses a target plate (surface) that is immersed in the plasma and connected to one end of an alumina rod while the opposite end of the alumina rod is mechanically connected to a titanium beam on which four strain gauges are mounted. The force on the target generates torque causing strain in the beam. The resulting strain measurements can be correlated to a force on the target plate. The alumina rod electrically and thermally isolates the target plate from the strain gauge beam and allows the strain gauges to be located out of the plasma flow while also serving as a moment arm of several inches to increase the strain in the beam at the strain gauge location. These force measurements correspond directly to momentum flux and may be used with known plasma conditions to place boundaries on the kinetic energies of the plasma and neutral particles. The force measurements may also be used to infer thrust produced by a plasma propulsive device. Stainless steel, titanium, molybdenum, and aluminum flat target plates have been used. Momentum flux measurements of H2, D2, He, and Ar plasmas produced in a magnetized plasma device have been performed.

  3. An α-synuclein gene (SNCA) polymorphism moderates the association of PTSD symptomatology with hazardous alcohol use, but not with aggression-related measures

    PubMed Central

    Guillot, Casey R.; Fanning, Jennifer R.; Liang, Tiebing; Leventhal, Adam M.; Berman, Mitchell E.

    2015-01-01

    Posttraumatic stress disorder (PTSD) often precedes comorbid substance use disorder and has been associated with aggression. Prior research has evidenced that alcohol use and other externalizing behaviors share genetic factors with PTSD; however, few studies have examined if specific genes are associated with externalizing behaviors in PTSD. The purpose of the current study was to investigate whether an α-synuclein gene polymorphism (SNCA rs356195) moderates the association of PTSD symptomatology with externalizing behaviors. We examined the separate and combined effects of PTSD symptomatology and SNCA rs356195 on alcohol- and aggression-related measures in nonclinical participants (N = 138 European Americans; 15 diagnosed with probable PTSD). Probable PTSD status and SNCA were both associated with externalizing measures. SNCA also moderated the association of PTSD symptomatology with hazardous alcohol use, but not with aggression-related measures. Current findings suggest that variations in SNCA may increase the likelihood that PTSD symptomatology results in excessive alcohol use. PMID:25594371

  4. Uncertainty of Five-Hole Probe Measurements. [of total flow pressure, static pressure, and flow

    NASA Technical Reports Server (NTRS)

    Reichert, Bruce A.; Wendt, Bruce J.

    1994-01-01

    A new algorithm for five-hole probe calibration and data reduction using a non-nulling technique was developed, verified, and reported earlier (Wendt and Reichert, 1993). The new algorithm's simplicity permits an analytical treatment of the propagation of uncertainty in five-hole probe measurement. The objectives of the uncertainty analysis are to quantify the uncertainty of five-hole probe results (e.g., total pressure, static pressure, and flow direction) and to determine the dependence of the result uncertainty on the uncertainty of all underlying experimental and calibration measurands. This study outlines a general procedure that other researchers may use to determine five-hole probe result uncertainty and provides guidance for improving the measurement technique.

  5. Applying velocity profiling technology to flow measurement at the Orinda water treatment plant

    SciTech Connect

    Metcalf, M.A.; Kachur, S.; Lackenbauer, S.

    1998-07-01

    A new type of flow measurement technology, velocity profiling, was tested in the South Channel of the Orinda Water Treatment Plant. This new technology allowed installation in the difficult hydraulic conditions of the South Channel, without interrupting plant operation. The advanced technology of velocity profiling enables flow measurements to be obtained in sites normally unusable by more traditional methods of flow rate measurement.

  6. Flow cytometric measurement of immunoglobulin E to natural latex proteins.

    PubMed Central

    Kwittken, P L; Pawlowski, N A; Sweinberg, S K; Douglas, S D; Campbell, D E

    1994-01-01

    Immediate hypersensitivity to natural latex (NL) occurs in sensitized individuals after repeated exposure to products or devices containing NL components. Since allergic reactions to NL proteins are quite frequent and may be quite serious, diagnostic assays are needed to identify individuals at risk. A number of latex proteins have been considered the major antigens, but they have been incompletely characterized. There is no standard material available for skin testing. In vitro diagnostic tests, such as the radioallergosorbent test (RAST), are time consuming and their sensitivity and specificity remain to be proven. We have developed a rapid microsphere-based, fluorescence-activated flow cytometry assay for the measurement of NL protein-specific human immunoglobulin E and have compared it with both the enzyme-linked immunosorbent assay and radioallergosorbent test methods. By using the total purified NL protein fraction isolated from raw ammoniated NL sap as the antigen, the flow cytometry assay was both sensitive and specific for the detection of NL protein-specific human immunoglobulin E in the sera of sensitized pediatric patients. PMID:7496945

  7. Velocity measurements on highly turbulent free surface flow using ADV

    NASA Astrophysics Data System (ADS)

    Cea, L.; Puertas, J.; Pena, L.

    2007-03-01

    The 3D instantaneous velocity recorded with an acoustic Doppler velocimeter (ADV) in a highly turbulent free surface flow is analysed using several filters in order to eliminate the corrupted data from the sample. The filters used include the minimum/maximum threshold, the acceleration threshold, and the phase-space threshold. Following some ideas of the phase-space filter, a new method based on the 3D velocity cross-correlation is proposed and tested. A way of computing the constants of the acceleration threshold method is proposed, so no parameters need to be fixed by the user, which makes the filtering process simpler, more objective and more efficient. All the samples analysed are highly turbulent. Nevertheless, the turbulence intensity and the air entrainment vary widely in the flow under study, which produces data records of different quality depending on the measurement point. The performance of the filtering methods when applied to samples of different quality, and the effects of the filtering process in the mean velocity, turbulent kinetic energy and frequency spectra are discussed.

  8. Flow Measurements over a Biomimetic Surface Roughness Microgeometry

    NASA Astrophysics Data System (ADS)

    Lang, Amy; Hidalgo, Pablo; Westcott, Matthew

    2007-11-01

    Certain species of sharks (e.g. shortfin mako) have a skin structure that results in a bristling of their denticles (scales) during increased swimming speeds. This unique surface geometry results in the formation of a 3D array of cavities* (d-type roughness geometry) within the shark skin, thus causing it to potentially act as a means of boundary layer control. Initial work is confined to scaling up the geometry from 0.2 mm on the shark skin to 2 cm, with a scaling down in characteristic velocity from 10 - 20 m/s to 10 - 20 cm/s for laminar flow boundary layer water tunnel studies over a shark skin model. The hypothesized formation of cavity vortices within the shark skin replica has been measured using DPIV. We have also shown that with the sufficient growth of a boundary layer upstream of the model (local Re = 200,000), transition is not tripped by the surface and the flow skips over the cavities. Support for this research by a NSF SGER grant (CTS-0630489), Lindbergh Foundation Grant and a University of Alabama RAC grant is gratefully acknowledged. * Patent pending.

  9. Characterization of moderate ash-and-gas explosions at Santiaguito volcano, Guatemala, from infrasound waveform inversion and thermal infrared measurements

    NASA Astrophysics Data System (ADS)

    Angelis, S. De; Lamb, O. D.; Lamur, A.; Hornby, A. J.; Aulock, F. W.; Chigna, G.; Lavallée, Y.; Rietbrock, A.

    2016-06-01

    The rapid discharge of gas and rock fragments during volcanic eruptions generates acoustic infrasound. Here we present results from the inversion of infrasound signals associated with small and moderate gas-and-ash explosions at Santiaguito volcano, Guatemala, to retrieve the time history of mass eruption rate at the vent. Acoustic waveform inversion is complemented by analyses of thermal infrared imagery to constrain the volume and rise dynamics of the eruption plume. Finally, we combine results from the two methods in order to assess the bulk density of the erupted mixture, constrain the timing of the transition from a momentum-driven jet to a buoyant plume, and to evaluate the relative volume fractions of ash and gas during the initial thrust phase. Our results demonstrate that eruptive plumes associated with small-to-moderate size explosions at Santiaguito only carry minor fractions of ash, suggesting that these events may not involve extensive magma fragmentation in the conduit.

  10. Quantitative phase-flow MR imaging in dogs by using standard sequences: comparison with in vivo flow-meter measurements.

    PubMed

    Pettigrew, R I; Dannels, W; Galloway, J R; Pearson, T; Millikan, W; Henderson, J M; Peterson, J; Bernardino, M E

    1987-02-01

    For evaluation of the feasibility and clinical potential of using the phase data from standard MR imaging sequences to measure blood flow, 11 vessels with diameters of 4 to 7 mm were imaged in seven dogs. The flow in either the superior mesenteric vein or the inferior vena cava was measured first at laparotomy (in ml/min) with electromagnetic flow meters. Immediately thereafter, these vessels were imaged by MR in 25-mm thick sections by using a standard spin echo (SE) 750/30 sequence with a Philips 0.5-T imager. Previous phase-flow calibration of the imager and sequence allowed calculation of the blood flow rates from the phase images that were used to measure the vessels' cross-sectional areas and blood phase values. Comparison of the measurements obtained with each technique showed a significant correlation (r = .977, p less than .05) between MR-imaging values and flow-meter measurements when the blood velocity was less than approximately 40 cm/sec, the known upper limit of the flow dynamic range for the MR hardware and sequence used. There was no correlation for blood velocities greater than 40 cm/sec. However, the range of blood flow velocities in dogs and man extends to more than 100 cm/sec. Thus, these results suggest that this technique might yield valuable adjunctive flow data in routine clinical imaging provided that improvements in hardware and software permit a larger dynamic range. PMID:2948376

  11. Hydrothermal vent flow and turbulence measurements with acoustic scintillation instrumentation

    NASA Astrophysics Data System (ADS)

    di Iorio, D.; Xu, G.

    2009-12-01

    Acoustically derived measurements of hydrothermal vent flow and turbulence were obtained from the active black smoker Dante in the Main Endeavour vent field, using scintillation analysis from one-way transmissions. The scintillation transmitter and receiver array formed a 93 m acoustic path through the buoyant plume 20 m above the structure. The acoustic path was parallel to the valley sidewall where the M2 tidal currents are approximately aligned along ridge due to topographic steering by the valley walls and hence most of the plume displacement is expected to occur along the acoustic path. On one deployment, data were collected for 6.5 weeks and vertical velocities range from 0.1 to 0.2 m/s showing a strong dependence on the spring/neap tidal cycle. The refractive index fluctuations which can be paramaterized in terms of the root-mean-square temperature fluctuations also shows a strong tidal modulation during spring tide.

  12. Turbulence Measurements of Separate Flow Nozzles with Mixing Enhancement Features

    NASA Technical Reports Server (NTRS)

    Bridges, James; Wernet, Mark P.

    2002-01-01

    Comparison of turbulence data taken in three separate flow nozzles, two with mixing enhancement features on their core nozzle, shows how the mixing enhancement features modify turbulence to reduce jet noise. The three nozzles measured were the baseline axisymmetric nozzle 3BB, the alternating chevron nozzle, 3A12B, with 6-fold symmetry, and the flipper tab nozzle 3T24B also with 6-fold symmetry. The data presented show the differences in turbulence characteristics produced by the geometric differences in the nozzles, with emphasis on those characteristics of interest in jet noise. Among the significant findings: the enhanced mixing devices reduce turbulence in the jet mixing region while increasing it in the fan/core shear layer, the ratios of turbulence components are significantly altered by the mixing devices, and the integral lengthscales do not conform to any turbulence model yet proposed. These findings should provide guidance for modeling the statistical properties of turbulence to improve jet noise prediction.

  13. Simultaneous drag and flow measurements of Olympic skeleton athletes

    NASA Astrophysics Data System (ADS)

    Moon, Yae Eun; Digiulio, David; Peters, Steve; Wei, Timothy

    2009-11-01

    The Olympic sport of skeleton involves an athlete riding a small sled face first down a bobsled track at speeds up to 130 km/hr. In these races, the difference between gold and missing the medal stand altogether can be hundredths of a second per run. As such, reducing aerodynamic drag through proper body positioning is of first order importance. To better study the flow behavior and to improve the performance of the athletes, we constructed a static force balance system on a mock section of a bobsled track. Athlete and the sled are placed on the force balance system which is positioned at the exit of an open loop wind tunnel. Simultaneous drag force and DPIV velocity field measurements were made along with video recordings of body position to aid the athletes in determining their optimal aerodynamic body position.

  14. Experimental Studies on the Measurement of Oil-water Two-phase Flow

    NASA Astrophysics Data System (ADS)

    Ma, Longbo; Zhang, Hongjian; Hua, Yuefang; Zhou, Hongliang

    2007-06-01

    Oil-water two-phase flow measurement was investigated with a Venturi meter and double-U Coriolis meter in this work. Based on the Venturi differential pressure and the quality of two-phase flow, a model for measuring oil-water mass flow rate was developed, in which fluid asymmetry of oil-water two-phase flow was considered. However, measuring the quality of two-phase flow on-line is rather difficult at present. Though double-U Coriolis meter can provide accurate measurement of two-phase flow, it can not provide desired respective mass flow rate. Therefore, a double-parameter measurement method with Venturi meter and double-U Coriolis meter is proposed. According to the flow rate requirement of Venturi, a new flow regime identification method based on Support Vector Machine (SVM) has been developed for the separated flow and the dispersed flow. With the Venturi model developed in this paper and mass flow rate of oil-water mixture measured with double-U Coriolis meter, mixture mass flow rate, oil mass flow rate and water mass flow rate could be obtained by the correlation. Experiments of flow rate measurement of oil-water two-phase flow were carried out in the horizontal tube with 25mm inner diameter. The water fraction range is from 5% to 95%. Experimental results showed that the flow regime could be identified well with SVM, and the relative error of the total mass flow rate and respective mass flow rate of oil-water two-phase flow was less than ±1.5% and ±10%, respectively.

  15. Noninvasive measurement of midexpiratory flow indicates bronchoconstriction in allergic rats.

    PubMed

    Glaab, Thomas; Hoymann, Heinz G; Hohlfeld, Jens M; Korolewitz, Regina; Hecht, Matthias; Alarie, Yves; Tschernig, Thomas; Braun, Armin; Krug, Norbert; Fabel, Helmut

    2002-10-01

    This study was designed to evaluate the value and applicability of tidal breathing pattern analysis to assess bronchoconstriction in conscious rats. Using noninvasive, head-out body plethysmography and the decrease in tidal midexpiratory flow (EF(50)), we measured airway responsiveness (AR) to inhaled acetylcholine and allergen in conscious Brown-Norway rats, followed by invasive determination of pulmonary conductance (GL) and EF(50) in anesthetized rats. Dose-response studies to acetylcholine showed that noninvasively recorded EF(50) closely reflected the dose-dependent decreases observed with the invasive monitoring of simultaneously measured GL and EF(50). After sensitization and intratracheal boost to ovalbumin or saline, rats were assessed for early and late AR to aerosolized ovalbumin. Ovalbumin aerosol challenge resulted in early and late AR in allergen-sensitized rats, whereas controls were unresponsive. The allergen-specific AR, as measured noninvasively by EF(50), was similar in degree compared with invasively recorded EF(50) and GL and was associated with enhanced IgE and airway inflammation. We conclude that EF(50) is a noninvasive and physiologically valid index of bronchoconstriction in a rat model of asthma. PMID:12235016

  16. Gas/liquid flow measurement using coriolis-based flow meters

    SciTech Connect

    Liu, K.T.; Nguyen, T.V.

    1991-07-09

    This patent describes a method of determining total mass flow rate and phase distribution of individual components in a flowing gas/liquid stream. It comprises flowing at least a first gas/liquid stream through a Coriolis-based flow meter, the first gas/liquid stream having a first known total mass flow rate and component phase distribution; obtaining a first apparent total mass flow rate output and a first apparent density output from the Coriolis- based mass flow meter; correlating the first known total mass flow rate and phase distribution with the first apparent mass flow rate output and the first apparent density output obtained from the Coriolis-based mass flow meter to determine a set of correlation equations; flowing a second gas/liquid stream through the Coriolis-based mass flow meter; obtaining a second apparent mass flow rate output and a second apparent density output from the Coriolis-based mass flow meter; calculating a total mass flow rate and a component phase distribution of the second gas/liquid stream based on the correlation equations and the second apparent mass flow rate output and the second apparent density output.

  17. Fabrication of rigid and flexible refractive-index-matched flow phantoms for flow visualisation and optical flow measurements

    NASA Astrophysics Data System (ADS)

    Geoghegan, P. H.; Buchmann, N. A.; Spence, C. J. T.; Moore, S.; Jermy, M.

    2012-05-01

    A method for the construction of both rigid and compliant (flexible) transparent flow phantoms of biological flow structures, suitable for PIV and other optical flow methods with refractive-index-matched working fluid is described in detail. Methods for matching the in vivo compliance and elastic wave propagation wavelength are presented. The manipulation of MRI and CT scan data through an investment casting mould is described. A method for the casting of bubble-free phantoms in silicone elastomer is given. The method is applied to fabricate flexible phantoms of the carotid artery (with and without stenosis), the carotid artery bifurcation (idealised and patient-specific) and the human upper airway (nasal cavity). The fidelity of the phantoms to the original scan data is measured, and it is shown that the cross-sectional error is less than 5% for phantoms of simple shape but up to 16% for complex cross-sectional shapes such as the nasal cavity. This error is mainly due to the application of a PVA coating to the inner mould and can be reduced by shrinking the digital model. Sixteen per cent variation in area is less than the natural patient to patient variation of the physiological geometries. The compliance of the phantom walls is controlled within physiologically realistic ranges, by choice of the wall thickness, transmural pressure and Young's modulus of the elastomer. Data for the dependence of Young's modulus on curing temperature are given for Sylgard 184. Data for the temperature dependence of density, viscosity and refractive index of the refractive-index-matched working liquid (i.e. water-glycerol mixtures) are also presented.

  18. Observations of debris flows at Chalk Cliffs, Colorado, USA: Part 1, in-situ measurements of flow dynamics, tracer particle movement and video imagery from the summer of 2009

    USGS Publications Warehouse

    McCoy, Scott W.; Coe, Jeffrey A.; Kean, Jason W.; Tucker, Greg E.; Staley, Dennis M.; Wasklewicz, Thad A.

    2011-01-01

    Debris flows initiated by surface-water runoff during short duration, moderate- to high-intensity rainfall are common in steep, rocky, and sparsely vegetated terrain. Yet large uncertainties remain about the potential for a flow to grow through entrainment of loose debris, which make formulation of accurate mechanical models of debris-flow routing difficult. Using a combination of in situ measurements of debris flow dynamics, video imagery, tracer rocks implanted with passive integrated transponders (PIT) and pre- and post-flow 2-cm resolution digital terrain models (terrain data presented in a companion paper by STALEY et alii, 2011), we investigated the entrainment and transport response of debris flows at Chalk Cliffs, CO, USA. Four monitored events during the summer of 2009 all initiated from surface-water runoff, generally less than an hour after the first measurable rain. Despite reach-scale morphology that remained relatively constant, the four flow events displayed a range of responses, from long-runout flows that entrained significant amounts of channel sediment and dammed the main-stem river, to smaller, short-runout flows that were primarily depositional in the upper basin. Tracer-rock travel-distance distributions for these events were bimodal; particles either remained immobile or they travelled the entire length of the catchment. The long-runout, large-entrainment flow differed from the other smaller flows by the following controlling factors: peak 10-minute rain intensity; duration of significant flow in the channel; and to a lesser extent, peak surge depth and velocity. Our growing database of natural debris-flow events can be used to develop linkages between observed debris-flow transport and entrainment responses and the controlling rainstorm characteristics and flow properties.

  19. A novel experimental setup for energy loss and charge state measurements in dense moderately coupled plasma using laser-heated hohlraum targets

    NASA Astrophysics Data System (ADS)

    Ortner, A.; Schumacher, D.; Cayzac, W.; Frank, A.; Basko, M. M.; Bedacht, S.; Blazevic, A.; Faik, S.; Kraus, D.; Rienecker, T.; Schaumann, G.; Tauschwitz, An.; Wagner, F.; Roth, M.

    2016-03-01

    We report on a new experimental setup for ion energy loss measurements in dense moderately coupled plasma which has recently been developed and tested at GSI Darmstadt. A partially ionized, moderately coupled carbon plasma (ne ≤ 0.8• 1022 cm-3, Te = 15 eV, z = 2.5, Γ = 0.5) is generated by volumetrical heating of two thin carbon foils with soft X-rays. This plasma is then probed by a bunched heavy ion beam. For that purpose, a special double gold hohlraum target of sub-millimeter size has been developed which efficiently converts intense laser light into thermal radiation and guarantees a gold-free interaction path for the ion beam traversing the carbon plasma. This setup allows to do precise energy loss measurements in non-ideal plasma at the level of 10 percent solid-state density.

  20. The Importance of Measurement Errors for Deriving Accurate Reference Leaf Area Index Maps for Validation of Moderate-Resolution Satellite LAI Products

    NASA Technical Reports Server (NTRS)

    Huang, Dong; Yang, Wenze; Tan, Bin; Rautiainen, Miina; Zhang, Ping; Hu, Jiannan; Shabanov, Nikolay V.; Linder, Sune; Knyazikhin, Yuri; Myneni, Ranga B.

    2006-01-01

    The validation of moderate-resolution satellite leaf area index (LAI) products such as those operationally generated from the Moderate Resolution Imaging Spectroradiometer (MODIS) sensor data requires reference LAI maps developed from field LAI measurements and fine-resolution satellite data. Errors in field measurements and satellite data determine the accuracy of the reference LAI maps. This paper describes a method by which reference maps of known accuracy can be generated with knowledge of errors in fine-resolution satellite data. The method is demonstrated with data from an international field campaign in a boreal coniferous forest in northern Sweden, and Enhanced Thematic Mapper Plus images. The reference LAI map thus generated is used to assess modifications to the MODIS LAI/fPAR algorithm recently implemented to derive the next generation of the MODIS LAI/fPAR product for this important biome type.

  1. Self-contained Tubular Compressed-flow Generation Device for Use in Making Differential Measurements

    NASA Technical Reports Server (NTRS)

    England, John D. (Inventor); Kelley, Anthony R. (Inventor); Cronise, Raymond J. (Inventor)

    2013-01-01

    A device used in making differential measurements of a flow includes an open-ended tubular flow obstruction and a support arm. The flow obstruction has an outer annular wall and an inner annular wall. The support arm has a first end coupled to an exterior wall of a conduit and a second end coupled to the flow obstruction. The support arm positions the flow obstruction in the conduit such that a first flow region is defined around the flow obstruction's outer annular wall and a second flow region is defined by the flow obstruction's inner annular wall. The support arm's first end and second end are separated from one another with respect to a length dimension of the conduit. Measurement ports provided in the flow obstruction are coupled to points at the exterior wall of the conduit by manifolds extending through the flow obstruction and support arm.

  2. MEASUREMENTS AND COMPUTATIONS OF FUEL DROPLET TRANSPORT IN TURBULENT FLOWS

    SciTech Connect

    Joseph Katz and Omar Knio

    2007-01-10

    The objective of this project is to study the dynamics of fuel droplets in turbulent water flows. The results are essential for development of models capable of predicting the dispersion of slightly light/heavy droplets in isotropic turbulence. Since we presently do not have any experimental data on turbulent diffusion of droplets, existing mixing models have no physical foundations. Such fundamental knowledge is essential for understanding/modeling the environmental problems associated with water-fuel mixing, and/or industrial processes involving mixing of immiscible fluids. The project has had experimental and numerical components: 1. The experimental part of the project has had two components. The first involves measurements of the lift and drag forces acting on a droplet being entrained by a vortex. The experiments and data analysis associated with this phase are still in progress, and the facility, constructed specifically for this project is described in Section 3. In the second and main part, measurements of fuel droplet dispersion rates have been performed in a special facility with controlled isotropic turbulence. As discussed in detail in Section 2, quantifying and modeling the of droplet dispersion rate requires measurements of their three dimensional trajectories in turbulent flows. To obtain the required data, we have introduced a new technique - high-speed, digital Holographic Particle Image Velocimetry (HPIV). The technique, experimental setup and results are presented in Section 2. Further information is available in Gopalan et al. (2005, 2006). 2. The objectives of the numerical part are: (1) to develop a computational code that combines DNS of isotropic turbulence with Lagrangian tracking of particles based on integration of a dynamical equation of motion that accounts for pressure, added mass, lift and drag forces, (2) to perform extensive computations of both buoyant (bubbles) and slightly buoyant (droplets) particles in turbulence conditions

  3. In vivo measurement of blood flow in the vitelline network

    NASA Astrophysics Data System (ADS)

    Poelma, Christian; Vennemann, Peter; Lindken, Ralph; Westerweel, Jerry

    2007-11-01

    The growth and adaptation of blood vessels is studied in vivo in the so-called vitelline network of a chick embryo. The vitelline network, a system of extra-embryonic blood vessels that transports nutrients from the yolk sac to the chick embryo, is an easily accessible model system for the study of human cardiovascular development and functioning. We present measurements obtained by means of scanning microscopic Particle Image Velocimetry. Using phase-locking, we can reconstruct the full three-dimensional flow as a function of the cardiac cycle. Typical reconstructed volumes are 0.4x0.5x0.2 mm^3 with a spatial resolution (i.e. vector spacing) of 6 μm. These hemodynamic measurements allow a study of the coupling between form and functioning of the blood vessels. Special attention is given to the local wall shear stress (WSS), an important physiological parameter that is thought to determine - to great extent - the adaptation of the vessels to changing conditions. The WSS can be estimated directly from the velocity gradient at the wall or from a fit to the blood velocity profile. The former method slightly underestimates the WSS (most likely due to lack of resolution) but is significantly easier to apply in the complex geometries under consideration.

  4. Measurement of physiological flow parameters with magnetic resonance

    NASA Astrophysics Data System (ADS)

    Dumoulin, Charles L.; Tarnawski, M.; Doorly, D. J.; Caro, C. G.; Darrow, R. D.

    1993-08-01

    Some phase-sensitive methods obtain a phase measurement for each voxel in an otherwise conventional image. In an alternative approach, data for a variety of flow-sensitive conditions are obtained and Fourier transformed to obtain a velocity 'spectrum'. Fourier velocity encoded data are highly accurate and are not degraded by velocity distributions within a voxel. One important application of Fourier velocity encoding is the non-invasive measurement of local vessel wall compliance. We have developed a new technique in which spin velocity information is acquired simultaneously for several stations along a vessel using a comb excitation rf pulse and Fourier velocity encoding. In the absence of pulse wave reflections, two stations separated by a sufficient distance are enough to calculate the velocity of the pressure wave, C. Once the wave velocity is known, it can be used to determine vessel wall distensibility, D, using the relationship D equals 1/((rho) C2), where (rho) is the density of blood. Preliminary data from a group of healthy volunteers suggest a strong correlation of local vessel compliance with physical fitness and age.

  5. Minimally destructive Doppler measurement of a quantized, superfluid flow

    NASA Astrophysics Data System (ADS)

    Anderson, Neil; Kumar, Avinash; Eckel, Stephen; Stringari, Sandro; Campbell, Gretchen

    2016-05-01

    Ring shaped Bose-Einstein condensates are of interest because they support the existence of quantized, persistent currents. These currents arise because in a ring trap, the wavefunction of the condensate must be single valued, and thus the azimuthal velocity is quantized. Previously, these persistent current states have only been measured in a destructive fashion via either interference with a phase reference or using the size of a central vortex-like structure that appears in time of flight. Here, we demonstrate a minimally destructive, in-situ measurement of the winding number of a ring shaped BEC. We excite a standing wave of phonon modes in the ring BEC using a perturbation. If the condensate is in a nonzero circulation state, then the frequency of these phonon modes are Doppler shifted, causing the standing wave to precess about the ring. From the direction and velocity of this precession, we can infer the winding number of the flow. For certain parameters, this technique can detect individual winding numbers with approximately 90% fidelity.

  6. MEASURING THE GALAXY CLUSTER BULK FLOW FROM WMAP DATA

    SciTech Connect

    Osborne, S. J.; Church, S. E.; Mak, D. S. Y.; Pierpaoli, E.

    2011-08-20

    We have looked for bulk motions of galaxy clusters in the Wilkinson Microwave Anisotropy Probe (WMAP) seven-year data. We isolate the kinetic Sunyaev-Zeldovich (SZ) signal by filtering the WMAP Q-, V-, and W-band maps with multi-frequency matched filters that utilize the spatial properties of the kinetic SZ signal to optimize detection. We try two filters: a filter that has no spectral dependence, and a filter that utilizes the spectral properties of the kinetic and thermal SZ signals to remove the thermal SZ bias. We measure the monopole and dipole spherical harmonic coefficients of the kinetic SZ signal, as well as the l = 2-5 modes, at the locations of 736 ROSAT observed galaxy clusters. We find no significant power in the kinetic SZ signal at these multipoles with either filter, consistent with the {Lambda}CDM prediction. Our limits are a factor of {approx}3 more sensitive than the claimed bulk flow detection of Kashlinsky et al. Using simulations we estimate that in maps filtered by our matched filter with no spectral dependence there is a thermal SZ dipole that would be mistakenly measured as a bulk motion of {approx}2000-4000 km s{sup -1}. For the WMAP data, the signal-to-noise ratio obtained with the unbiased filter is almost an order of magnitude lower.

  7. Doppler global velocimetry measurements of the vortical flow above an F/A-18

    NASA Astrophysics Data System (ADS)

    Lee, Joseph W.; Meyers, James F.; Cavone, Angelo A.; Suzuki, Karen E.

    1993-01-01

    A Doppler global velocimeter is employed to study the vortical flow above an F/A-18 at 25 degree angle of attack. The measurements indicate that the flow possessed the same characteristics as the vortical flow above a standard delta wing. Image to image comparisons clearly indicate that the flow striking the vertical stabilizers is not chaotic.

  8. In vivo retinal blood flow measurement by Fourier domain Doppler optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Wang, Yimin; Tan, Ou; Huang, David

    2008-02-01

    The measurement of ocular blood flow is important in studying the pathophysiology and treatment of several leading causes of blindness. We present a method for in vivo human retinal flow measurement using Fourier domain optical coherence tomography. A double circular scanning pattern was used to scan the blood vessels around the optic nerve head 8 times over 2 seconds. The venous flow totaled 36.13 μl/min in the right eye of a volunteer. The flow difference was observed before and after breath holding. The fast flow measurement method did not require any assumption on the flow profile over time or space.

  9. Optical and acoustical measuring techniques. [for Doppler measurement of flow velocities

    NASA Technical Reports Server (NTRS)

    Cliff, W. C.

    1977-01-01

    The paper reviews the techniques of laser and acoustic Doppler measurement of fluid velocities in confined and free flows. The main mathematical relations are presented, and some systems are studied. Resolution properties of coaxial, bistatic, and pulsed CO2 laser Doppler velocimeter systems are compared. Schematics for pulsed and continuous wave acoustic Doppler systems are discussed. Both of these types of systems benefit from using a bistatic configuration instead of a coaxial system. The pulsed systems avoid contamination of source noise by not sampling until after the source noise has passed the receiver. Comparison of wind velocity measured with a pulsed acoustic Doppler and with a boundary layer profile is made.

  10. Multidirectional plasma flow measurement by Gundestrup Probe in scrape-off layer of ADITYA tokamak

    SciTech Connect

    Sangwan, Deepak; Jha, Ratneshwar; Tanna, Rakesh L.

    2015-11-15

    Multidirectional plasma flow measurements by using Gundestrup Probe in the scrape-off layer of ADITYA tokamak are presented. The ADITYA Gundestrup Probe-head consists of eight plates arranged around the ceramic rod and three pins normal to side plates. Plates are used to measure both parallel and perpendicular flows simultaneously and pins are used to measure plasma density and floating potential. A comparison of direct perpendicular flow measurement and by two other plates of Gundestrup Probe is presented. Possible causes of perpendicular flows are identified and compared with the measured flows. It is observed that the mechanism of the parallel flow and the perpendicular flow is different only at high parallel Mach number. A puff of the working gas is used to study its effect on the perpendicular flows and its reversal with the gas puff is observed.

  11. Improving the reliability of venous Doppler flow measurements: relevance of combined ECG, training and repeated measures.

    PubMed

    Staelens, Anneleen S E; Tomsin, Kathleen; Oben, Jolien; Mesens, Tinne; Grieten, Lars; Gyselaers, Wilfried

    2014-07-01

    The nature of venous Doppler waves is highly variable. An additional electrocardiogram (ECG) improves the interpretation of venous Doppler wave characteristics and allows measurement of venous pulse transit time. The purpose of this study was to assess the reproducibility of ECG-guided repeated measurements of venous Doppler flow characteristics before and after sonographer training and the inter- and intra-observer variability. In four groups of 25 healthy women, venous Doppler flow measurements were performed at the level of the kidneys and liver according to a standardized protocol. Intra-observer Pearson correlation coefficients of the renal interlobar vein Doppler indices were ≥ 0.80 with the addition of the ECG, which are higher than the results of a former study. The inter-observer correlation between an experienced ultrasonographer and an inexperienced ultrasonographer improved from ≥ 0.71 to ≥ 0.91 after training. The correlation range of all parameters between two independent observers improved when values were based on repeated measures. The addition of an ECG to the Doppler image, training and repeated measurements are helpful in improving venous Doppler wave interpretation. PMID:24631376

  12. Validation of an optical flow algorithm to measure blood flow waveforms in arteries using dynamic digital x-ray images

    NASA Astrophysics Data System (ADS)

    Rhode, Kawal; Lambrou, Tryphon; Hawkes, David J.; Hamilton, George; Seifalian, Alexander M.

    2000-06-01

    We have developed a weighted optical flow algorithm for the extraction of instantaneous blood velocity from dynamic digital x-ray images of blood vessels. We have carried out in- vitro validation of this technique. A pulsatile physiological blood flow circuit was constructed using sections of silicone tubing to simulate blood vessels with whole blood as the fluid. Instantaneous recording of flow from an electromagnetic flow meter (EMF) provided the gold standard measurement. Biplanar dynamic digital x-ray images of the blood vessel with injection of contrast medium were acquired at 25 fps using a PC frame capture card. Imaging of a Perspex calibration cube allowed 3D reconstruction of the vessel and determination of true dimensions. Blood flow waveforms were calculated off-line on a Sun workstation using the new algorithm. The correlation coefficient between instantaneous blood flow values obtained from the EMF and the x-ray method was r equals 0.871, n equals 1184, p less than 0.0001. The correlation coefficient for average blood flow was r equals 0.898, n equals 16, p less than 0.001. We have successfully demonstrated that our new algorithm can measure pulsatile blood flow in a vessel phantom. We aim to use this algorithm to measure blood flow clinically in patients undergoing vascular interventional procedures.

  13. European multicentre double-blind placebo-controlled trial of Nilvadipine in mild-to-moderate Alzheimer's disease—the substudy protocols: NILVAD frailty; NILVAD blood and genetic biomarkers; NILVAD cerebrospinal fluid biomarkers; NILVAD cerebral blood flow

    PubMed Central

    Meulenbroek, Olga; O'Dwyer, Sarah; de Jong, Daan; van Spijker, Gerrita; Kennelly, Sean; Cregg, Fiona; Olde Rikkert, Marcel; Abdullah, Laila; Wallin, Anders; Walsh, Cathal; Coen, Robert; Kenny, Rose Anne; Daly, Leslie; Segurado, Ricardo; Borjesson-Hanson, Anne; Crawford, Fiona; Mullan, Michael; Lucca, Ugo; Banzi, Rita; Pasquier, Florence; Breuilh, Laetitia; Riepe, Matthias; Kalman, Janos; Tsolaki, Magda; Howard, Robert; Adams, Jessica; Gaynor, Siobhan; Lawlor, Brian

    2016-01-01

    Introduction In conjunction with the NILVAD trial, a European Multicentre Double-Blind Placebo Controlled trial of Nilvadipine in Mild-to-Moderate Alzheimer's disease (AD), there are four NILVAD substudies in which eligible NILVAD patients are also invited to participate. The main NILVAD protocol was previously published in BMJ Open (2014). The objectives of the NILVAD substudies are to determine whether frailty, cerebrospinal fluid (CSF), blood biomarker profile and Apolipoprotein E (APOE) status predict response to Nilvadipine, and to investigate the effect of Nilvadipine on cerebral blood flow and blood biomarkers. Methods and analysis All participants who fulfil criteria for the main NILVAD study are eligible for participation in the NILVAD substudies. Participation is subject to informed consent and whether the substudy is available at a particular NILVAD study site. Each substudy entails extra measurements during the course of the main NILVAD study. For example, in the blood and genetic biomarkers substudy, extra blood (30 mL) will be collected at week 0, week 13, week 52 and week 78, while in the cerebral blood flow substudy, participants will receive an MRI and transcranial Doppler measurements at week 0, week 26 and week 78. In the CSF substudy, 10 mL CSF is collected at week 0 and week 78. Ethics and dissemination All NILVAD substudies and all subsequent amendments have received ethical approval within each participating country, according to national regulations. Each participant provides written consent to participate. All participants remain anonymised throughout and the results of each substudy will be published in an international peer reviewed journal. Trial registration number EUDRACT 2012-002764-27; Pre-results. PMID:27436668

  14. In vivo label-free measurement of lymph flow velocity and volumetric flow rates using Doppler optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Blatter, Cedric; Meijer, Eelco F. J.; Nam, Ahhyun S.; Jones, Dennis; Bouma, Brett E.; Padera, Timothy P.; Vakoc, Benjamin J.

    2016-07-01

    Direct in vivo imaging of lymph flow is key to understanding lymphatic system function in normal and disease states. Optical microscopy techniques provide the resolution required for these measurements, but existing optical techniques for measuring lymph flow require complex protocols and provide limited temporal resolution. Here, we describe a Doppler optical coherence tomography platform that allows direct, label-free quantification of lymph velocity and volumetric flow rates. We overcome the challenge of very low scattering by employing a Doppler algorithm that operates on low signal-to-noise measurements. We show that this technique can measure lymph velocity at sufficiently high temporal resolution to resolve the dynamic pulsatile flow in collecting lymphatic vessels.

  15. In vivo label-free measurement of lymph flow velocity and volumetric flow rates using Doppler optical coherence tomography.

    PubMed

    Blatter, Cedric; Meijer, Eelco F J; Nam, Ahhyun S; Jones, Dennis; Bouma, Brett E; Padera, Timothy P; Vakoc, Benjamin J

    2016-01-01

    Direct in vivo imaging of lymph flow is key to understanding lymphatic system function in normal and disease states. Optical microscopy techniques provide the resolution required for these measurements, but existing optical techniques for measuring lymph flow require complex protocols and provide limited temporal resolution. Here, we describe a Doppler optical coherence tomography platform that allows direct, label-free quantification of lymph velocity and volumetric flow rates. We overcome the challenge of very low scattering by employing a Doppler algorithm that operates on low signal-to-noise measurements. We show that this technique can measure lymph velocity at sufficiently high temporal resolution to resolve the dynamic pulsatile flow in collecting lymphatic vessels. PMID:27377852

  16. Measurement of Flows in the HSX Stellarator Demonstrating the Importance of Momentum-Conservation in Neoclassical Flow Modeling

    NASA Astrophysics Data System (ADS)

    Briesemeister, A.; Lore, J.; Zhai, K.; Anderson, D. T.; Anderson, F. S. B.; Talmadge, J. N.

    2010-11-01

    The flow velocity of carbon ions is measured using a Charge Exchange Recombination Spectroscopy (CHERS) system on the Helically Symmetric Experiment (HSX), a quasi-helically symmetric stellarator. Intrinsic parallel flow speeds of up to 20km/s have been measured. The parallel velocity is compared to the predictions of the PENTA code [1-2]. Multiple ion species, including the species used for the CHERS measurements, are included in the calculations. PENTA is a neoclassical code that includes the effects of momentum-conservation, which are often neglected for nonsymmetric stellarators. Without momentum conservation the parallel flow velocity in HSX is under-predicted by approximately an order of magnitude. Agreement is seen between the measured and calculated parallel flows when momentum conservation is included.[4pt] [1] D.A. Spong, Phys. Plasmas 12 (2005) 056114.[0pt] [2] J. Lore et al, Phys. Plasmas 17 (2010) 056101.

  17. In vivo label-free measurement of lymph flow velocity and volumetric flow rates using Doppler optical coherence tomography

    PubMed Central

    Blatter, Cedric; Meijer, Eelco F. J.; Nam, Ahhyun S.; Jones, Dennis; Bouma, Brett E.; Padera, Timothy P.; Vakoc, Benjamin J.

    2016-01-01

    Direct in vivo imaging of lymph flow is key to understanding lymphatic system function in normal and disease states. Optical microscopy techniques provide the resolution required for these measurements, but existing optical techniques for measuring lymph flow require complex protocols and provide limited temporal resolution. Here, we describe a Doppler optical coherence tomography platform that allows direct, label-free quantification of lymph velocity and volumetric flow rates. We overcome the challenge of very low scattering by employing a Doppler algorithm that operates on low signal-to-noise measurements. We show that this technique can measure lymph velocity at sufficiently high temporal resolution to resolve the dynamic pulsatile flow in collecting lymphatic vessels. PMID:27377852

  18. Measurements of inlet flow distortions in an axial flow fan (6 and 9 blade rotor)

    NASA Technical Reports Server (NTRS)

    Barr, L. C.

    1978-01-01

    A large quantity of experimental data on inlet flow distortions in an axial flow fan were obtained. The purpose of the study was to determine the effects of design and operating variables and the type of distortion on the response of an axial flow turbomachinery rotor. Included are background information and overall trends observed in distortion attenuation and unsteady total pressure losses.

  19. Measurements of Complex Oceanic Flows, from Turbulence in the Coastal Ocean to Interaction of Zooplankton with its Local Environment

    NASA Astrophysics Data System (ADS)

    Katz, J.

    2004-03-01

    The presentation has two parts, both dealing with flow structure, turbulence and flow-particle interactions in the ocean. The first part examines PIV data obtained in the bottom boundary layer of the coastal ocean in periods when the mean currents are higher, of the same order and weaker than the wave induced motions. The energy spectra display substantial anisotropy at all scales, and the flow consists of periods of "gusts" dominated by large vortical structures, separated by periods of quiescent flows. The frequency of these gusts increases with Reynolds number, and they disappear when the currents are weak. Conditional sampling shows that the Reynolds shear stress, and as a result the shear production, are generated only during periods of gusts. When the mean flow is weak and during quiescent periods of moderate flow the shear stresses are essentially zero. Dissipation, on the other hand, occurs continuously, and increases only slightly during gust periods. The second part focuses on interactions of zooplankton with the local flow. Digital in-line holographic cinematography is used for measuring the three-dimensional trajectory of a free-swimming copepod, and simultaneously the instantaneous 3-D velocity field around this copepod. The velocity field and trajectory of particles entrained by the copepod have a recirculating pattern in the copepod's frame of reference. This pattern is caused by the copepod sinking at a rate that is lower than its terminal sinking speed, due to the propulsive force generated by its feeding current. Consequently, the copepod has to hop periodically to scan different fluid for food. Using Stokeslets to model the velocity field, the measured velocity distributions enable us to estimate the excess weight of the copepod and the propulsive force generated by its feeding appendages. Sponsored in part by the Office of Naval Research and by the National Science Foundation.

  20. Oscillatory motion based measurement method and sensor for measuring wall shear stress due to fluid flow

    DOEpatents

    Armstrong, William D.; Naughton, Jonathan; Lindberg, William R.

    2008-09-02

    A shear stress sensor for measuring fluid wall shear stress on a test surface is provided. The wall shear stress sensor is comprised of an active sensing surface and a sensor body. An elastic mechanism mounted between the active sensing surface and the sensor body allows movement between the active sensing surface and the sensor body. A driving mechanism forces the shear stress sensor to oscillate. A measuring mechanism measures displacement of the active sensing surface relative to the sensor body. The sensor may be operated under periodic excitation where changes in the nature of the fluid properties or the fluid flow over the sensor measurably changes the amplitude or phase of the motion of the active sensing surface, or changes the force and power required from a control system in order to maintain constant motion. The device may be operated under non-periodic excitation where changes in the nature of the fluid properties or the fluid flow over the sensor change the transient motion of the active sensor surface or change the force and power required from a control system to maintain a specified transient motion of the active sensor surface.