Science.gov

Sample records for air velocity profiles

  1. Velocity profile development for a poultry facility acid scrubber

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Determination of the air velocity profile for 12 experimental configurations (ECs) of an acid scrubber was carried out using an equal area traverse method with a vane axial anemometer. Four velocity profile plots were created for each configuration to determine the four optimal ECs. ECs were selecte...

  2. Velocity profiles in laminar diffusion flames

    NASA Technical Reports Server (NTRS)

    Lyons, Valerie J.; Margle, Janice M.

    1986-01-01

    Velocity profiles in vertical laminar diffusion flames were measured by using laser Doppler velocimetry (LDV). Four fuels were used: n-heptane, iso-octane, cyclohexane, and ethyl alcohol. The velocity profiles were similar for all the fuels, although there were some differences in the peak velocities. The data compared favorably with the theoretical velocity predictions. The differences could be attributed to errors in experimental positioning and in the prediction of temperature profiles. Error in the predicted temperature profiles are probably due to the difficulty in predicting the radiative heat losses from the flame.

  3. Similarity of the Velocity Profile

    DTIC Science & Technology

    2014-10-01

    su x (with 0 constantb = ) is the empirically derived velocity scale developed by Zagarola and Smits [5] for turbulent boundary layer flow...Zagarola and Smits and others have shown that the velocity scaling factor given by Eq. 5 with sδ as the boundary layer thickness can collapse certain...and Smits , it is important to point out that the fact that the similarity length scale factor and the similarity velocity scale factor must follow

  4. Temperature and velocity profiles in sooting free boundary layer flames

    NASA Technical Reports Server (NTRS)

    Ang, J. A.; Pagni, P. J.; Mataga, T. G.; Margle, J. M.; Lyons, V. J.

    1986-01-01

    Temperature and velocity profiles are presented for cyclohexane, n-heptane, and iso-octane free, laminar, boundary layer, sooting, diffusion flames. Temperatures are measured with 3 mil Pt/Pt-13 percent Rh thermocouples. Corrected gas temperatures are derived by performing an energy balance of convection to and radiation from the thermocouple bead incorporating the variation of air conductivity and platinum emissivity with temperature. Velocities are measured using laser doppler velocimetry techniques. Profiles are compared with previously reported analytic temperature and velocity fields. Comparison of theoretical and experimental temperature profiles suggests improvement in the analytical treatment is needed, which accounts more accurately for the local soot radiation. The velocity profiles are in good agreement, with the departure of the theory from observation partially due to the small fluctuations inherent in these free flows.

  5. Air Velocity Mapping of Environmental Test Chambers

    DTIC Science & Technology

    1989-07-01

    variable that must be measured for the evaluations of the air diffusion performance index (ADPI), or the thermal comfort indices such as predicted mean...altered. The impact of asymmetrical airflow patterns undoubtedly affect human thermal comfort votes. The standardized 6 technique described in this...report could be easily employed prior to or along with specific studies requiring precise air velocity data, and coupled with human thermal comfort surveys

  6. Air velocity distribution in a commercial broiler house

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Increasing air velocity during tunnel ventilation in commercial broiler production facilities improves production efficiency, and many housing design specifications require a minimum air velocity. Air velocities are typically assessed with a hand-held velocity meter at random locations, rather than ...

  7. Measuring velocity and temperature profile sectional pipeline behind confuser

    NASA Astrophysics Data System (ADS)

    Siažik, Ján; Malcho, Milan; Lenhard, Richard; Novomestský, Marcel

    2016-06-01

    The article deals with the measuring of temperature and velocity profile in area behind confuser in real made scale model of bypass. For proper operation of the equipment it is necessary to know the actual flow in the pipe. Bypasses have wide application and can be also associated with devices for heat recovery, heat exchangers different designs in which may be used in certain circumstances. In the present case, the heat that would otherwise has not been used is used for heating of insulators, and heating the air in the spray-dryer. The measuring principle was verify how the above-mentioned temperature and velocity profile decomposition above confuser on real made scale model.

  8. An approximate compact analytical expression for the Blasius velocity profile

    NASA Astrophysics Data System (ADS)

    Savaş, Ö.

    2012-10-01

    A single-term, two-parameter, hyperbolic tangent function is presented to describe the flow profiles in the Blasius boundary layer, which reproduces the streamwise velocity profile within 0.003 (0.3% of free stream velocity) of its numerical exact solution throughout the flow. The function can be inverted for an implicit description of the velocity profile.

  9. 30 CFR 75.326 - Mean entry air velocity.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Mean entry air velocity. 75.326 Section 75.326... MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Ventilation § 75.326 Mean entry air velocity. In exhausting face ventilation systems, the mean entry air velocity shall be at least 60 feet per...

  10. 30 CFR 75.326 - Mean entry air velocity.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... concentrations in accordance with the applicable levels. Mean entry air velocity shall be determined at or near... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Mean entry air velocity. 75.326 Section 75.326... MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Ventilation § 75.326 Mean entry air velocity....

  11. 30 CFR 75.326 - Mean entry air velocity.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... concentrations in accordance with the applicable levels. Mean entry air velocity shall be determined at or near... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Mean entry air velocity. 75.326 Section 75.326... MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Ventilation § 75.326 Mean entry air velocity....

  12. 30 CFR 75.326 - Mean entry air velocity.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... concentrations in accordance with the applicable levels. Mean entry air velocity shall be determined at or near... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Mean entry air velocity. 75.326 Section 75.326... MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Ventilation § 75.326 Mean entry air velocity....

  13. 30 CFR 75.326 - Mean entry air velocity.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... concentrations in accordance with the applicable levels. Mean entry air velocity shall be determined at or near... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Mean entry air velocity. 75.326 Section 75.326... MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Ventilation § 75.326 Mean entry air velocity....

  14. Optical Pickup Feeding Velocity Profile Design of Optical Disk Storage

    NASA Astrophysics Data System (ADS)

    Park, Juhn Ho; Seo, Heui-Sik; Lee, Jung Joon; Min, Byunghoon; Son, Heuigi

    2001-03-01

    Residual vibrations and jerks of a pickup body caused by the flexibility of an optical pickup feeding system in optical disk storage may degrade the quality of reading and writing, and increase the track access time. In this study, a feeding velocity profile that suppresses the residual vibrations and jerks is calculated and applied to a stepping-motor-driven feeding system. The calculated feeding velocity profile shows good results compared to the conventional feeding velocity profile of trapezoidal shape.

  15. Simulation of air velocity in a vertical perforated air distributor

    NASA Astrophysics Data System (ADS)

    Ngu, T. N. W.; Chu, C. M.; Janaun, J. A.

    2016-06-01

    Perforated pipes are utilized to divide a fluid flow into several smaller streams. Uniform flow distribution requirement is of great concern in engineering applications because it has significant influence on the performance of fluidic devices. For industrial applications, it is crucial to provide a uniform velocity distribution through orifices. In this research, flow distribution patterns of a closed-end multiple outlet pipe standing vertically for air delivery in the horizontal direction was simulated. Computational Fluid Dynamics (CFD), a tool of research for enhancing and understanding design was used as the simulator and the drawing software SolidWorks was used for geometry setup. The main purpose of this work is to establish the influence of size of orifices, intervals between outlets, and the length of tube in order to attain uniformity of exit flows through a multi outlet perforated tube. However, due to the gravitational effect, the compactness of paddy increases gradually from top to bottom of dryer, uniform flow pattern was aimed for top orifices and larger flow for bottom orifices.

  16. Velocity Estimate Following Air Data System Failure

    DTIC Science & Technology

    2008-03-01

    12 Figure 2.2. Pitot Tube...that relay pitot -static information from the aircraft’s air data system and inertial measurement information from the Inertial Navigation System...Air data systems receive total and static pressure inputs from a pitot -static system. A typical pitot tube, as shown below, receives total pressure

  17. Measuring discharge with ADCPs: Inferences from synthetic velocity profiles

    USGS Publications Warehouse

    Rehmann, C.R.; Mueller, D.S.; Oberg, K.A.

    2009-01-01

    Synthetic velocity profiles are used to determine guidelines for sampling discharge with acoustic Doppler current profilers (ADCPs). The analysis allows the effects of instrument characteristics, sampling parameters, and properties of the flow to be studied systematically. For mid-section measurements, the averaging time required for a single profile measurement always exceeded the 40 s usually recommended for velocity measurements, and it increased with increasing sample interval and increasing time scale of the large eddies. Similarly, simulations of transect measurements show that discharge error decreases as the number of large eddies sampled increases. The simulations allow sampling criteria that account for the physics of the flow to be developed. ?? 2009 ASCE.

  18. VPV--The velocity profile viewer user manual

    USGS Publications Warehouse

    Donovan, John M.

    2004-01-01

    The Velocity Profile Viewer (VPV) is a tool for visualizing time series of velocity profiles developed by the U.S. Geological Survey (USGS). The USGS uses VPV to preview and present measured velocity data from acoustic Doppler current profilers and simulated velocity data from three-dimensional estuarine, river, and lake hydrodynamic models. The data can be viewed as an animated three-dimensional profile or as a stack of time-series graphs that each represents a location in the water column. The graphically displayed data are shown at each time step like frames of animation. The animation can play at several different speeds or can be suspended on one frame. The viewing angle and time can be manipulated using mouse interaction. A number of options control the appearance of the profile and the graphs. VPV cannot edit or save data, but it can create a Post-Script file showing the velocity profile in three dimensions. This user manual describes how to use each of these features. VPV is available and can be downloaded for free from the World Wide Web at http://ca.water.usgs.gov/program/sfbay/vpv.

  19. The EM-POGO: A simple, absolute velocity profiler

    NASA Astrophysics Data System (ADS)

    Terker, S. R.; Sanford, T. B.; Dunlap, J. H.; Girton, J. B.

    2013-01-01

    Electromagnetic current instrumentation has been added to the Bathy Systems, Inc. POGO transport sondes to produce a free-falling absolute velocity profiler called EM-POGO. The POGO is a free-fall profiler that measures a depth-averaged velocity using GPS fixes at the beginning and end of a round trip to the ocean floor (or a preset depth). The EM-POGO adds a velocity profile determined from measurements of motionally induced electric fields generated by the ocean current moving through the vertical component of the Earth's magnetic field. In addition to providing information about the vertical structure of the velocity, the depth-dependent measurements improve transport measurements by correcting for the non-constant fall-rate. Neglecting the variable fall rate results in errors O (1 cm s-1). The transition from POGO to EM-POGO included electrically isolating the POGO and electric-field-measuring circuits, installing a functional GPS receiver, finding a pressure case that provided an optimal balance among crush-depth, price and size, and incorporating the electrodes, electrode collar, and the circuitry required for the electric field measurement. The first EM-POGO sea-trial was in July 1999. In August 2006 a refurbished EM-POGO collected 15 absolute velocity profiles; relative and absolute velocity uncertainty was ˜1cms-1 and 0.5-5 cm s-1, respectively, at a vertical resolution of 25 m. Absolute velocity from the EM-POGO compared to shipboard ADCP measurements differed by ˜ 1-2 cm s-1, comparable to the uncertainty in absolute velocity from the ADCP. The EM-POGO is thus a low-cost, easy to deploy and recover, and accurate velocity profiler.

  20. Velocity profiles between two baffles in a horizontal circular tube

    NASA Astrophysics Data System (ADS)

    Chang, Tae-Hyun; Lee, Hae-Soo; Oh, Keon-Je; Doh, Doeg Hee; Lee, Chang-Hoan

    2014-12-01

    The shell and tube heat exchanger is an essential part of a power plant for recovering heat transfer between the feed water of a boiler and the wasted heat. The baffles are also an important element inside the heat exchanger. Internal materials influence the flow pattern in the bed. The influence of baffles in the velocity profiles was observed using a three-dimensional particle image velocimetry around baffles in a horizontal circular tube. The velocity of the particles was measured before the baffle and between them in the test tube. Results show that the flows near the front baffle flow were parallel to the vertical wall, and then concentrate on the upper opening of the front baffle. The flows circulate in the front and rear baffles. These flow profiles are related to the Reynolds number (Re) or the flow intensity. The velocity profiles at lower Re number showed a complicated mixing, concentrating on the lower opening of the rear baffle as front wall. Swirling flow was employed in this study, which was produced using tangential velocities at the inlet. At the entrance of the front baffle, the velocity vector profiles with swirl were much different from that without swirl. However, velocities between two baffles are not much different from those without swirl.

  1. A new test chamber to measure material emissions under controlled air velocity

    SciTech Connect

    Bortoli, M. de; Ghezzi, E.; Knoeppel, H.; Vissers, H.

    1999-05-15

    A new 20-L glass chamber for the determination of VOC emissions from construction materials and consumer products under controlled air velocity and turbulence is described. Profiles of air velocity and turbulence, obtained with precisely positioned hot wire anemometric probes, show that the velocity field is homogeneous and that air velocity is tightly controlled by the fan rotation speed; this overcomes the problem of selecting representative positions to measure air velocity above a test specimen. First tests on material emissions show that the influence of air velocity on the emission rate of VOCs is negligible for sources limited by internal diffusion and strong for sources limited by evaporation. In a velocity interval from 0.15 to 0.30 m s{sup {minus}1}, an emission rate increase of 50% has been observed for pure n-decane and 1,4-dichlorobenzene and of 30% for 1,2-propanediol from a water-based paint. In contrast, no measurable influence of turbulence could be observed during vaporization of 1,4-dichlorobenzene within a 3-fold turbulence interval. Investigations still underway show that the chamber has a high recovery for the heavier VOC (TXIB), even at low concentrations.

  2. Design of passively aerated compost piles: Vertical air velocities between the pipes

    SciTech Connect

    Lynch, N.J.; Cherry, R.S.

    1996-09-01

    Passively aerated compost piles are built on a base of porous materials, such as straw or wood chips, in which perforated air supply pipes are distributed. The piles are not turned during composting, nor is forced-aeration equipment used, which significantly reduces the operating and capital expenses associated with these piles. Currently, pile configurations and materials are worked out by trial and error. Fundamentally based design procedures are difficult to develop because the natural convection air flow rate is not explicitly known, but rather is closely coupled with the pile temperature. This paper develops a mathematical model to analytically determine the maximum upward air flow velocity over an air supply pipe and the drop in vertical velocity away from the pipe. This model has one dimensionless number, dependent on the pile and base properties, which fully characterizes the velocity profile between the pipes. 9 refs., 4 figs., 1 tab.

  3. Air velocity distributions inside tree canopies from a variable-rate air-assisted sprayer

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A variable-rate, air assisted, five-port sprayer had been in development to achieve variable discharge rates of both liquid and air. To verify the variable air rate capability by changing the fan inlet diameter of the sprayer, air jet velocities impeded by plant canopies were measured at various loc...

  4. VELOCITY DISPERSION PROFILE OF THE MILKY WAY HALO

    SciTech Connect

    Brown, Warren R.; Geller, Margaret J.; Kenyon, Scott J.; Diaferio, Antonaldo E-mail: mgeller@cfa.harvard.edu E-mail: diaferio@ph.unito.it

    2010-01-15

    We present a spectroscopic sample of 910 distant halo stars from the Hypervelocity Star survey from which we derive the velocity dispersion profile of the Milky Way halo. The sample is a mix of 74% evolved horizontal branch stars and 26% blue stragglers. We estimate distances to the stars using observed colors, metallicities, and stellar evolution tracks. Our sample contains twice as many objects with R > 50 kpc as previous surveys. We compute the velocity dispersion profile in two ways: with a parametric method based on a Milky Way potential model and with a non-parametric method based on the caustic technique originally developed to measure galaxy cluster mass profiles. The resulting velocity dispersion profiles are remarkably consistent with those found by two independent surveys based on other stellar populations: the Milky Way halo exhibits a mean decline in radial velocity dispersion of -0.38 {+-} 0.12 km s{sup -1} kpc{sup -1} over 15 < R < 75 kpc. This measurement is a useful basis for calculating the total mass and mass distribution of the Milky Way halo.

  5. Normalized velocity profiles of field-measured turbidity currents

    USGS Publications Warehouse

    Xu, Jingping

    2010-01-01

    Multiple turbidity currents were recorded in two submarine canyons with maximum speed as high as 280 cm/s. For each individual turbidity current measured at a fixed station, its depth-averaged velocity typically decreased over time while its thickness increased. Some turbidity currents gained in speed as they traveled downcanyon, suggesting a possible self-accelerating process. The measured velocity profiles, first in this high resolution, allowed normalizations with various schemes. Empirical functions, obtained from laboratory experiments whose spatial and time scales are two to three orders of magnitude smaller, were found to represent the field data fairly well. The best similarity collapse of the velocity profiles was achieved when the streamwise velocity and the elevation were normalized respectively by the depth-averaged velocity and the turbidity current thickness. This normalization scheme can be generalized to an empirical function Y = exp(–αXβ) for the jet region above the velocity maximum. Confirming theoretical arguments and laboratory results of other studies, the field turbidity currents are Froude-supercritical.

  6. ADL ORVIS: An air-delay-leg, line-imaging optically recording velocity interferometer system

    NASA Astrophysics Data System (ADS)

    Trott, Wayne M.; Castañeda, Jaime N.; Cooper, Marcia A.

    2014-04-01

    An interferometry system that enables acquisition of spatially resolved velocity-time profiles with very high velocity sensitivity has been designed and applied to two diverse, instructive experimental problems: (1) measurement of low-amplitude reverberations in laser-driven flyer plates and (2) measurement of ramp-wave profiles in symmetric impact studies of fused silica. The delay leg in this version of a line-imaging optically recording velocity interferometer system (ORVIS) consists of a long air path that includes relay optics to transmit the optical signal through the interferometer cavity. Target image quality from the delay path at the image recombination plane is preserved by means of a compact and flexible optical design utilizing two parabolic reflectors (serving as the relay optics) in a folded path. With an instrument tuned to a velocity per fringe constant of 22.4 m s-1 fringe-1, differences of 1-2 m s-1 across the probe line segment can be readily distinguished. Measurements that capture small spatial variations in flyer velocity are presented and briefly discussed. In the fused silica impact experiments, the ramp-wave profile observed by this air-delay instrument compares favorably to the profile recorded simultaneously by a conventional line-imaging ORVIS.

  7. On the Universality of the Bound Zone Peculiar Velocity Profile

    NASA Astrophysics Data System (ADS)

    Lee, Jounghun

    2016-12-01

    Numerical evidence for the universality of the bound-zone peculiar velocity profile in a “Λ+Cold Dark Matter” (ΛCDM) universe is presented. Analyzing the dark matter halo catalogs from the Millennium-II simulation, we determine the average peculiar velocity profiles of the objects located in the bound zones around massive group-size halos at various redshifts and compare them to an analytic formula characterized by two parameters, the amplitude and slope of the profile. The best-fit values of the two parameters are found to be robust against the changes of the mass scales and the key cosmological parameters. It is also found that the amplitude and slope parameters of the bound-zone peculiar velocity profile are constant, but only in the limited ranges of redshifts. In the dark matter dominated epoch corresponding to z > 0.6, the two parameters have constant values. In the transition period corresponding to 0.2 ≤ z ≤ 0.6, when the density of Λ begins to exceed that of dark matter, the two parameters grow almost linearly with redshifts. At later epochs with z < 0.2, when the Λ-domination prevails, the two parameters regain constancy, settling upon higher constant values. Noting that the length of the transition period depends on the amount of Λ, and speculating that the linear evolution of the profile, with redshifts in the transition period, is a unique feature of the Λ-dominated universe, we suggest that the redshift evolution of the bound-zone peculiar velocity profile should be a powerful local discriminator of dark energy candidates.

  8. Effect of velocity profile skewing on blood velocity and volume flow waveforms derived from maximum Doppler spectral velocity.

    PubMed

    Mynard, Jonathan P; Steinman, David A

    2013-05-01

    Given evidence that fully developed axisymmetric flow may be the exception rather than the rule, even in nominally straight arteries, maximum velocity (V(max)) can lie outside the Doppler sample volume (SV). The link between V(max) and derived quantities, such as volume flow (Q), may therefore be more complex than commonly thought. We performed idealized virtual Doppler ultrasound on data from image-based computational fluid dynamics (CFD) models of the normal human carotid artery and investigated how velocity profile skewing and choice of sample volume affected V(max) waveforms and derived Q variables, considering common assumptions about velocity profile shape (i.e., Poiseuille or Womersley). Severe velocity profile skewing caused substantial errors in V(max) waveforms when using a small, centered SV, although peak V(max) was reliably detected; errors with a long SV covering the vessel diameter were orientation dependent but lower overall. Cycle-averaged Q calculated from V(max) was typically within ±15%, although substantial skewing and use of a small SV caused 10%-25% underestimation. Peak Q derived from Womersley's theory was generally accurate to within ±10%. V(max) pulsatility and resistance indexes differed from Q-based values, although the Q-based resistance index could be predicted reliably. Skewing introduced significant error into V(max)-derived Q waveforms, particularly during mid-to-late systole. Our findings suggest that errors in the V(max) and Q waveforms related to velocity profile skewing and use of a small SV, or orientation-dependent errors for a long SV, could limit their use in wave analysis or for constructing characteristic or patient-specific flow boundary conditions for model studies.

  9. Noise from Supersonic Coaxial Jets. Part 3; Inverted Velocity Profile

    NASA Technical Reports Server (NTRS)

    Dahl, Milo D.; Morris, Philip J.

    1997-01-01

    The instability wave noise generation model is used to study the instability waves in the two shear layers of an inverted velocity profile, supersonic, coaxial jet and the noise radiated from the dominant wave. The inverted velocity profile jet has a high speed outer stream surrounding a low speed inner stream and the outer shear layer is always larger than the inner shear layer. The jet mean flows are calculated numerically. The operating conditions are chosen to exemplify the effect of the coaxial jet outer shear layer initial spreading rates. Calculations are made for the stability characteristics in the coaxial jet shear layers and the noise radiated from the instability waves for different operating conditions with the same total thrust, mass flow and exit area as a single reference jet. Results for inverted velocity profile jets indicate that relative maximum instability wave amplitudes and far field peak noise levels can be reduced from that of the reference jet by having higher spreading rates for the outer shear layer, low velocity ratios, and outer streams hotter than the inner stream.

  10. Noise from Supersonic Coaxial Jets. Part 2; Normal Velocity Profile

    NASA Technical Reports Server (NTRS)

    Dahl, M. D.; Morris, P. J.

    1997-01-01

    Instability waves have been established as noise generators in supersonic jets. Recent analysis of these slowly diverging jets has shown that these instability waves radiate noise to the far field when the waves have components with phase velocities that are supersonic relative to the ambient speed of sound. This instability wave noise generation model has been applied to supersonic jets with a single shear layer and is now applied to supersonic coaxial jets with two initial shear layers. In this paper the case of coaxial jets with normal velocity profiles is considered, where the inner jet stream velocity is higher than the outer jet stream velocity. To provide mean flow profiles at all axial locations, a numerical scheme is used to calculate the mean flow properties. Calculations are made for the stability characteristics in the coaxial jet shear layers and the noise radiated from the instability waves for different operating conditions with the same total thrust, mass flow and exit area as a single reference jet. The effects of changes in the velocity ratio, the density ratio and the area ratio are each considered independently.

  11. Air velocity distributions from a variable-rate air-assisted sprayer for tree applications

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A capability that implements tree structure to control liquid and air flow rates is the preferential design in the development of variable-rate orchard and nursery sprayers. Air jet velocity distributions from an air assisted, five-port sprayer which was under the development to achieve variable-rat...

  12. Velocity profiles in idealized model of human respiratory tract

    NASA Astrophysics Data System (ADS)

    Elcner, J.; Jedelsky, J.; Lizal, F.; Jicha, M.

    2013-04-01

    This article deals with numerical simulation focused on velocity profiles in idealized model of human upper airways during steady inspiration. Three r gimes of breathing were investigated: Resting condition, Deep breathing and Light activity which correspond to most common regimes used for experiments and simulations. Calculation was validated with experimental data given by Phase Doppler Anemometry performed on the model with same geometry. This comparison was made in multiple points which form one cross-section in trachea near first bifurcation of bronchial tree. Development of velocity profile in trachea during steady inspiration was discussed with respect for common phenomenon formed in trachea and for future research of transport of aerosol particles in human respiratory tract.

  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. Diffusive mixing through velocity profile variation in microchannels

    NASA Astrophysics Data System (ADS)

    Yakhshi-Tafti, Ehsan; Cho, Hyoung J.; Kumar, Ranganathan

    2011-03-01

    Rapid mixing does not readily occur at low Reynolds number flows encountered in microdevices; however, it can be enhanced by passive diffusive mixing schemes. This study of micromixing of two miscible fluids is based on the principle that (1) increased velocity at the interface of co-flowing fluids results in increased diffusive mass flux across their interface, and (2) diffusion interfaces between two liquids progress transversely as the flow proceeds downstream. A passive micromixer is proposed that takes advantage of the peak velocity variation, inducing diffusive mixing. The effect of flow variation on the enhancement of diffusive mixing is investigated analytically and experimentally. Variation of the flow profile is confirmed using micro-Particle Image Velocimetry (μPIV) and mixing is evaluated by color variations resulting from the mixing of pH indicator and basic solutions. Velocity profile variations obtained from μPIV show a shift in peak velocities. The mixing efficiency of the Σ-micromixer is expected to be higher than that for a T-junction channel and can be as high as 80%. The mixing efficiency decreases with Reynolds number and increases with downstream length, exhibiting a power law.

  15. Pressure and velocity profiles in a static mechanical hemilarynx model.

    PubMed

    Alipour, Fariborz; Scherer, Ronald C

    2002-12-01

    This study examined pressure and velocity profiles in a hemilarynx mechanical model of phonation. The glottal section had parallel walls and was fabricated from hard plastic. Twelve pressure taps were created in the vocal fold surface and connected to a differential pressure transducer through a pressure switch. The glottal gap was measured with feeler gauges and the uniform glottal duct was verified by use of a laser system. Eight pressure transducers were placed in the flat wall opposite the vocal fold. Hot-wire anemometry was used to obtain velocity profiles upstream and downstream of the glottis. The results indicate that the pressure distribution on the vocal fold surface was consistent with pressure change along a parallel duct, whereas the pressures on the opposite flat wall typically were lower (by 8%-40% of the transglottal pressure just past mid-glottis). The upstream velocity profiles were symmetric regardless of the constriction shape and size. The jet flow downstream of the glottis was turbulent even for laminar upstream conditions. The front of the jet was consistently approximately 1.5 mm from the flat wall for glottal gaps of 0.4, 0.8 and 1.2 mm. The turbulence intensity also remained approximately at the same location of about 4 mm from the flat wall for the two larger gaps.

  16. Mean velocity and temperature profiles in a sheared diabatic turbulent boundary layer

    NASA Astrophysics Data System (ADS)

    Li, Dan; Katul, Gabriel G.; Bou-Zeid, Elie

    2012-10-01

    In the atmospheric surface layer, modifications to the logarithmic mean velocity and air temperature profiles induced by thermal stratification or convection are accounted for via stability correction functions ϕm and ϕh, respectively, that vary with the stability parameter ς. These two stability correction functions are presumed to be universal in shape and independent of the surface characteristics. To date, there is no phenomenological theory that explains all the scaling laws in ϕh with ς, how ϕh relates to ϕm, and why ϕh ⩽ ϕm is consistently reported. To develop such a theory, the recently proposed links between the mean velocity profile and the Kolmogorov spectrum of turbulence, which were previously modified to account for the effects of buoyancy, are generalized here to include the mean air temperature profile. The resulting theory explains the observed scaling laws in ϕm and ϕh reported in many field and numerical experiments, predicts their behaviors across a wide range of atmospheric stability conditions, and elucidates why heat is transported more efficiently than momentum in certain stability regimes. In particular, it is shown that the enhancement in heat transport under unstable conditions is linked to a "scale-resonance" between turnover eddies and excursions in the instantaneous air temperature profiles. Excluding this scale-resonance results in the conventional Reynolds analogy with ϕm = ϕh across all stability conditions.

  17. Velocity Profiles in a Rotating Drum: The Effects of Cohesion

    NASA Astrophysics Data System (ADS)

    Brewster, Robert C.; Silbert, Leonardo E.; Grest, Gary S.; Levine, Alex J.

    2007-03-01

    The dynamics of granular media in a rotating drum is important in a wide range of applications in industry associated with mixing granular materials. The rotating drum also serves as a standard experimental geometry to observe continuous avalanching in the laboratory. We study the effect of interparticle cohesion on the velocity field of the rotating drum using large scale granular dynamics simulations. Such cohesion is easily introduced in the system by a wetting fluid that forms menisci at interparticle contacts. Previously, we have examined the effect of interparticle cohesion in gravity driven chute flows, and have shown that the cohesion has a dramatic effect on the granular rheology. For strong enough cohesion, these forces generate a coherently moving plug at the free surface. In this talk, we examine the velocity profile in the rotating drum geometry in this plug-flow regime. We compare our results for angle of the pile in the continuous flow regime to the experiments of Nowak et al. [Nature Physics, 1 (2005)] and we examine the stress and velocity profile within the pile as well.

  18. Hα LINE PROFILE ASYMMETRIES AND THE CHROMOSPHERIC FLARE VELOCITY FIELD

    SciTech Connect

    Kuridze, D.; Mathioudakis, M.; Kennedy, M.; Keenan, F. P.; Simões, P. J. A.; Voort, L. Rouppe van der; Fletcher, L.; Carlsson, M.; Jafarzadeh, S.; Allred, J. C.; Kowalski, A. F.; Graham, D.

    2015-11-10

    The asymmetries observed in the line profiles of solar flares can provide important diagnostics of the properties and dynamics of the flaring atmosphere. In this paper the evolution of the Hα and Ca ii λ8542 lines are studied using high spatial, temporal, and spectral resolution ground-based observations of an M1.1 flare obtained with the Swedish 1 m Solar Telescope. The temporal evolution of the Hα line profiles from the flare kernel shows excess emission in the red wing (red asymmetry) before flare maximum and excess in the blue wing (blue asymmetry) after maximum. However, the Ca ii λ8542 line does not follow the same pattern, showing only a weak red asymmetry during the flare. RADYN simulations are used to synthesize spectral line profiles for the flaring atmosphere, and good agreement is found with the observations. We show that the red asymmetry observed in Hα is not necessarily associated with plasma downflows, and the blue asymmetry may not be related to plasma upflows. Indeed, we conclude that the steep velocity gradients in the flaring chromosphere modify the wavelength of the central reversal in the Hα line profile. The shift in the wavelength of maximum opacity to shorter and longer wavelengths generates the red and blue asymmetries, respectively.

  19. Effects of radial and circumferential inlet velocity profile distortions on performance of a short-length double-annular ram induction combustor

    NASA Technical Reports Server (NTRS)

    Schultz, D. F.; Perkins, P. J.

    1972-01-01

    Inlet air velocity profile tests were conducted on a full-scale short-length 102-centimeter-diameter annual combustor designed for advanced gas turbine engine applications. The inlet profiles studied include radial distortions that were center peaked, and tip peaked, as well as a circumferential distortion which was center peaked for one-third of the circumference and flat for the other two-thirds. An increase in combustor pressure loss was the most significant effect of the radial air velocity distortions. With the circumferential distortion, exit temperature pattern factor doubled when compared to a flat velocity profile.

  20. Velocity and phase distribution measurements in vertical air-water annular flows

    SciTech Connect

    Vassallo, P.

    1997-07-01

    Annular flow topology for three air-water conditions in a vertical duct is investigated through the use of a traversing double-sensor hot-film anemometry probe and differential pressure measurements. Near wall measurements of mean and fluctuating velocities, as well as local void fraction, are taken in the liquid film, with the highest turbulent fluctuations occurring for the flow condition with the largest pressure drop. A modified law-of-the-wall formulation for wall shear is presented which, using near wall values of mean velocity and kinetic energy, agrees reasonably well with the average stress obtained from direct pressure drop measurements. The linear profile using wall coordinates in the logarithmic layer is preserved in annular flow; however, the slope and intercept of the profile differ from the single-phase values for the annular flow condition which has a thicker, more turbulent, liquid film.

  1. A New Wind Profiler Trajectory Tool for Air Quality Studies

    NASA Astrophysics Data System (ADS)

    White, A. B.; Senff, C. J.; Keane, A. N.; Koury, J.

    2003-12-01

    The Cooperative Institute for Research in Environmental Sciences, the NOAA Environmental Technology Laboratory (NOAA/ETL), and the Science and Technology Corporation have developed a new online tool for producing forward and backward trajectories from hourly wind profiles measured by a network of boundary-layer wind profilers. The tool is intended to aid scientists and forecasters in the planning and execution of field operations during the 2004 Northeast North Atlantic Air Quality Study. This study will involve an international consortium of agencies and will include upwards of a dozen of research aircraft and the NOAA research vessel Ronald H. Brown. The purpose of this talk is to demonstrate the tool and collect feedback from scientific investigators, which we will use to modify the tool before the 2004 field study. In addition, we will present preliminary results from the 2002 New England Air Quality Study that demonstrate the value of using continuous profiler observations instead of numerical model initialization fields to calculate trajectories for the meteorologically complex coastal zone of New England. The trajectory tool uses the horizontal wind profiles measured by the profiler network that are collected in near-real time and archived at NOAA/ETL's facility in Boulder, Colorado. The vertical velocities are not used because of large uncertainty in the profiler's vertical velocity measurement. To calculate hourly trajectory positions, the horizontal winds are interpolated in space using an inverse distance squared weighting. Users may request altitude ranges for the trajectories as well as start and end times and trajectory starting/end points. Trajectories are plotted on a two dimensional map background and are color coded by their respective altitude range.

  2. Measurements of the bulk and interfacial velocity profiles in oscillating Newtonian and Maxwellian fluids.

    PubMed

    Torralba, M; Castrejón-Pita, J R; Castrejón-Pita, A A; Huelsz, G; del Río, J A; Ortín, J

    2005-07-01

    We present the dynamic velocity profiles of a Newtonian fluid (glycerol) and a viscoelastic Maxwell fluid (CPyCl-NaSal in water) driven by an oscillating pressure gradient in a vertical cylindrical pipe. The frequency range explored has been chosen to include the first three resonance peaks of the dynamic permeability of the viscoelastic-fluid--pipe system. Three different optical measurement techniques have been employed. Laser Doppler anemometry has been used to measure the magnitude of the velocity at the center of the liquid column. Particle image velocimetry and optical deflectometry are used to determine the velocity profiles at the bulk of the liquid column and at the liquid-air interface respectively. The velocity measurements in the bulk are in good agreement with the theoretical predictions of a linear theory. The results, however, show dramatic differences in the dynamic behavior of Newtonian and viscoelastic fluids, and demonstrate the importance of resonance phenomena in viscoelastic fluid flows, biofluids in particular, in confined geometries.

  3. Measurement of velocity of air flow in the sinus maxillaris.

    PubMed

    Müsebeck, K; Rosenberg, H

    1979-03-01

    Anemometry with the hot wire and hot film technique previously described, enables the rhinologist to record slow and rapidly changing air flow in the maxillary sinus. The advantages and disadvantages of this method are considered. Anemometry together with manometry may be designated sinumetry and used as a diagnostic procedure following sinuscopy in chronic maxillary sinus disease. The value of the function from velocity of time allows the estimation of flow-volume in the sinus. Furthermore, the method is useful to evaluate the optimal therapy to restore ventilation in the case of an obstructed ostium demonstrated before and after surgical opening in the inferior meatus.

  4. Drift Velocity of Electrons in Hot and Moist Air mixtures

    NASA Astrophysics Data System (ADS)

    Abner, Douglas

    1999-10-01

    The drift velocity of electrons in hot and moist air is presented. The apparatus consisted of a pulsed Townsend-type drift tube with an oil-free vacuum system and employed a temperature controller and heating system to regulate the temperature of the gas mixture and chamber to within 0.1 deg. C. over a range of ambient to 200 deg C. The drift tube is equipped with a movable anode allowing the anode-cathode separation to be varied from 0.8 to 7.4 cm. Water vapor concentration in the air mixture ranged from 0.7510.0Temperature was varied from ambient to 150 deg C. E/N (electric field normalized to gas density) ranged from 1.0 to 16 Td (1 Td = 10-17 V-cm2). Comparisons of data collected at elevated temperature, data collected at ambient temperature, and Boltzmann transport equation calculations show the effects of enhanced rotational and vibrational populations on the drift velocity.

  5. What is the velocity profile of debris flows?

    NASA Astrophysics Data System (ADS)

    Walter, Fabian; McArdell, Brian

    2015-04-01

    cross-correlation scheme after calculating the signal envelope and low pass filtering it. In this sense, we do not target individual particle impacts. Rather, we measure debris flow velocities by tracking activity bursts across sensor triplets sharing the same height. Our method is therefore ideally applied to debris flows, whose geophone records show long-term modulations of signal amplitudes. For certain debris flow records our procedure provides vertical flow velocity profiles. We compare these with independent measurements of debris flow front speeds and flow depths. Furthermore, we discuss important limitations of the shear wall set up. Specifically, the channel bed below the instruments is erodible and thus varying with time. Moreover, debris deposits near the channel wall may locally perturb the debris flow and thus divert it from the direction parallel to the channel centerline. Nevertheless, we believe that our vertical flow profile results are the first of their kind and shed light on the interior of a debris flow, which is usually shielded from direct observations.

  6. Hot air vulcanization of rubber profiles

    SciTech Connect

    Gerlach, J.

    1995-07-01

    Elastomer profiles are deployed in quantity by the automobile industry as seals and wateproofing in coachwork. The high standards demanded by the industry; improvement in weather prediction, noise reduction, restriction of tolerances, together with powerful demand for EPDM force the rubber processing industry into development, particularly of elastomers. Complex proofing systems must also be achieved with extremely complicated profile forms. All too often such profiles have an extremely large surface together with a low cross-section density. They frequently consist of two or three rubber compounds and are steel reinforced. Sometimes they are flocked and coated with a low friction finish. Such high-tech seals require an adjustment of the vulcanization method. The consistent trend in the nineties towards lower quantities of elastomer per sealing unit and the dielectric factor, especially with EPDM, has brought an old fashioned vulcanization method once more to the fore, a method developed over the past years to an extremely high standard, namely the hot-air method. This paper describes various vulcanization and curing methods and their relative merits and disadvantages, the Gerlach hot-air concept, the hot air installation concept, and energy saving and efficiency afforded by this technique. 4 figs.

  7. Impact of AIRS Thermodynamic Profile on Regional Weather Forecast

    NASA Technical Reports Server (NTRS)

    Chou, Shih-Hung; Zavodsky, Brad; Jedlovee, Gary

    2010-01-01

    Prudent assimilation of AIRS thermodynamic profiles and quality indicators can improve initial conditions for regional weather models. AIRS-enhanced analysis has warmer and moister PBL. Forecasts with AIRS profiles are generally closer to NAM analyses than CNTL. Assimilation of AIRS leads to an overall QPF improvement in 6-h accumulated precipitation forecasts. Including AIRS profiles in assimilation process enhances the moist instability and produces stronger updrafts and a better precipitation forecast than the CNTL run.

  8. Multiple Velocity Profile Measurements in Hypersonic Flows Using Sequentially-Imaged Fluorescence Tagging

    NASA Technical Reports Server (NTRS)

    Bathel, Brett F.; Danehy, Paul M.; Inman, Jennifer A.; Jones, Stephen B.; Ivey,Christopher b.; Goyne, Christopher P.

    2010-01-01

    Nitric-oxide planar laser-induced fluorescence (NO PLIF) was used to perform velocity measurements in hypersonic flows by generating multiple tagged lines which fluoresce as they convect downstream. For each laser pulse, a single interline, progressive scan intensified CCD (charge-coupled device) camera was used to obtain two sequential images of the NO molecules that had been tagged by the laser. The CCD configuration allowed for sub-microsecond acquisition of both images, resulting in sub-microsecond temporal resolution as well as sub-mm spatial resolution (0.5-mm horizontal, 0.7-mm vertical). Determination of axial velocity was made by application of a cross-correlation analysis of the horizontal shift of individual tagged lines. A numerical study of measured velocity error due to a uniform and linearly-varying collisional rate distribution was performed. Quantification of systematic errors, the contribution of gating/exposure duration errors, and the influence of collision rate on temporal uncertainty were made. Quantification of the spatial uncertainty depended upon the signal-to-noise ratio of the acquired profiles. This velocity measurement technique has been demonstrated for two hypersonic flow experiments: (1) a reaction control system (RCS) jet on an Orion Crew Exploration Vehicle (CEV) wind tunnel model and (2) a 10-degree half-angle wedge containing a 2-mm tall, 4-mm wide cylindrical boundary layer trip. The experiments were performed at the NASA Langley Research Center's 31-Inch Mach 10 Air Tunnel.

  9. Egomotion estimation with optic flow and air velocity sensors.

    PubMed

    Rutkowski, Adam J; Miller, Mikel M; Quinn, Roger D; Willis, Mark A

    2011-06-01

    We develop a method that allows a flyer to estimate its own motion (egomotion), the wind velocity, ground slope, and flight height using only inputs from onboard optic flow and air velocity sensors. Our artificial algorithm demonstrates how it could be possible for flying insects to determine their absolute egomotion using their available sensors, namely their eyes and wind sensitive hairs and antennae. Although many behaviors can be performed by only knowing the direction of travel, behavioral experiments indicate that odor tracking insects are able to estimate the wind direction and control their absolute egomotion (i.e., groundspeed). The egomotion estimation method that we have developed, which we call the opto-aeronautic algorithm, is tested in a variety of wind and ground slope conditions using a video recorded flight of a moth tracking a pheromone plume. Over all test cases that we examined, the algorithm achieved a mean absolute error in height of 7% or less. Furthermore, our algorithm is suitable for the navigation of aerial vehicles in environments where signals from the Global Positioning System are unavailable.

  10. 42 CFR 84.140 - Air velocity and noise levels; hoods and helmets; minimum requirements.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 42 Public Health 1 2014-10-01 2014-10-01 false Air velocity and noise levels; hoods and helmets... PROTECTIVE DEVICES Supplied-Air Respirators § 84.140 Air velocity and noise levels; hoods and helmets; minimum requirements. Noise levels generated by the respirator will be measured inside the hood or...

  11. 42 CFR 84.140 - Air velocity and noise levels; hoods and helmets; minimum requirements.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 42 Public Health 1 2013-10-01 2013-10-01 false Air velocity and noise levels; hoods and helmets... PROTECTIVE DEVICES Supplied-Air Respirators § 84.140 Air velocity and noise levels; hoods and helmets; minimum requirements. Noise levels generated by the respirator will be measured inside the hood or...

  12. 42 CFR 84.140 - Air velocity and noise levels; hoods and helmets; minimum requirements.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Air velocity and noise levels; hoods and helmets... PROTECTIVE DEVICES Supplied-Air Respirators § 84.140 Air velocity and noise levels; hoods and helmets; minimum requirements. Noise levels generated by the respirator will be measured inside the hood or...

  13. 42 CFR 84.140 - Air velocity and noise levels; hoods and helmets; minimum requirements.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 42 Public Health 1 2011-10-01 2011-10-01 false Air velocity and noise levels; hoods and helmets... PROTECTIVE DEVICES Supplied-Air Respirators § 84.140 Air velocity and noise levels; hoods and helmets; minimum requirements. Noise levels generated by the respirator will be measured inside the hood or...

  14. 42 CFR 84.140 - Air velocity and noise levels; hoods and helmets; minimum requirements.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 42 Public Health 1 2012-10-01 2012-10-01 false Air velocity and noise levels; hoods and helmets... PROTECTIVE DEVICES Supplied-Air Respirators § 84.140 Air velocity and noise levels; hoods and helmets; minimum requirements. Noise levels generated by the respirator will be measured inside the hood or...

  15. Effect of wind tunnel air velocity on VOC flux rates from CAFO manure and wastewater

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Wind tunnels and flux chambers are often used to estimate volatile organic compound (VOC) emissions from animal feeding operations (AFOs) without regard to air velocity or sweep air flow rates. Laboratory experiments were conducted to evaluate the effect of wind tunnel air velocity on VOC emission ...

  16. Drop size distribution and air velocity measurements in air assist swirl atomizer sprays

    NASA Technical Reports Server (NTRS)

    Mao, C.-P.; Oechsle, V.; Chigier, N.

    1987-01-01

    Detailed measurements of mean drop size (SMD) and size distribution parameters have been made using a Fraunhofer diffraction particle sizing instrument in a series of sprays generated by an air assist swirl atomizer. Thirty-six different combinations of fuel and air mass flow rates were examined with liquid flow rates up to 14 lbm/hr and atomizing air flow rates up to 10 lbm/hr. Linear relationships were found between SMD and liquid to air mass flow rate ratios. SMD increased with distance downstream along the center line and also with radial distance from the axis. Increase in obscuration with distance downstream was due to an increase in number density of particles as the result of deceleration of drops and an increase in the exposed path length of the laser beam. Velocity components of the atomizing air flow field measured by a laser anemometer show swirling jet air flow fields with solid body rotation in the core and free vortex flow in the outer regions.

  17. Velocity Fields of Axisymmetric Hydrogen-Air Counterflow Diffusion Flames from LDV, PIV, and Numerical Computation

    NASA Technical Reports Server (NTRS)

    Pellett, Gerald L.; Wilson, Lloyd G.; Humphreys, William M., Jr.; Bartram, Scott M.; Gartrell, Luther R.; Isaac, K. M.

    1995-01-01

    Laminar fuel-air counterflow diffusion flames (CFDFs) were studied using axisymmetric convergent-nozzle and straight-tube opposed jet burners (OJBs). The subject diagnostics were used to probe a systematic set of H2/N2-air CFDFs over wide ranges of fuel input (22 to 100% Ha), and input axial strain rate (130 to 1700 Us) just upstream of the airside edge, for both plug-flow and parabolic input velocity profiles. Laser Doppler Velocimetry (LDV) was applied along the centerline of seeded air flows from a convergent nozzle OJB (7.2 mm i.d.), and Particle Imaging Velocimetry (PIV) was applied on the entire airside of both nozzle and tube OJBs (7 and 5 mm i.d.) to characterize global velocity structure. Data are compared to numerical results from a one-dimensional (1-D) CFDF code based on a stream function solution for a potential flow input boundary condition. Axial strain rate inputs at the airside edge of nozzle-OJB flows, using LDV and PIV, were consistent with 1-D impingement theory, and supported earlier diagnostic studies. The LDV results also characterized a heat-release hump. Radial strain rates in the flame substantially exceeded 1-D numerical predictions. Whereas the 1-D model closely predicted the max I min axial velocity ratio in the hot layer, it overpredicted its thickness. The results also support previously measured effects of plug-flow and parabolic input strain rates on CFDF extinction limits. Finally, the submillimeter-scale LDV and PIV diagnostics were tested under severe conditions, which reinforced their use with subcentimeter OJB tools to assess effects of aerodynamic strain, and fueVair composition, on laminar CFDF properties, including extinction.

  18. 42 CFR 84.1139 - Air velocity and noise levels; hoods and helmets; minimum requirements.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Air velocity and noise levels; hoods and helmets... Efficiency Respirators and Combination Gas Masks § 84.1139 Air velocity and noise levels; hoods and helmets; minimum requirements. Noise levels generated by the respirator will be measured inside the hood or...

  19. 42 CFR 84.202 - Air velocity and noise levels; hoods and helmets; minimum requirements.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 42 Public Health 1 2011-10-01 2011-10-01 false Air velocity and noise levels; hoods and helmets... PROTECTIVE DEVICES Chemical Cartridge Respirators § 84.202 Air velocity and noise levels; hoods and helmets; minimum requirements. Noise levels generated by the respirator will be measured inside the hood or...

  20. 42 CFR 84.1139 - Air velocity and noise levels; hoods and helmets; minimum requirements.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 42 Public Health 1 2013-10-01 2013-10-01 false Air velocity and noise levels; hoods and helmets... Efficiency Respirators and Combination Gas Masks § 84.1139 Air velocity and noise levels; hoods and helmets; minimum requirements. Noise levels generated by the respirator will be measured inside the hood or...

  1. 42 CFR 84.1139 - Air velocity and noise levels; hoods and helmets; minimum requirements.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 42 Public Health 1 2014-10-01 2014-10-01 false Air velocity and noise levels; hoods and helmets... Efficiency Respirators and Combination Gas Masks § 84.1139 Air velocity and noise levels; hoods and helmets; minimum requirements. Noise levels generated by the respirator will be measured inside the hood or...

  2. 42 CFR 84.202 - Air velocity and noise levels; hoods and helmets; minimum requirements.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 42 Public Health 1 2012-10-01 2012-10-01 false Air velocity and noise levels; hoods and helmets... PROTECTIVE DEVICES Chemical Cartridge Respirators § 84.202 Air velocity and noise levels; hoods and helmets; minimum requirements. Noise levels generated by the respirator will be measured inside the hood or...

  3. 42 CFR 84.202 - Air velocity and noise levels; hoods and helmets; minimum requirements.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 42 Public Health 1 2013-10-01 2013-10-01 false Air velocity and noise levels; hoods and helmets... PROTECTIVE DEVICES Chemical Cartridge Respirators § 84.202 Air velocity and noise levels; hoods and helmets; minimum requirements. Noise levels generated by the respirator will be measured inside the hood or...

  4. 42 CFR 84.1139 - Air velocity and noise levels; hoods and helmets; minimum requirements.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 42 Public Health 1 2011-10-01 2011-10-01 false Air velocity and noise levels; hoods and helmets... Efficiency Respirators and Combination Gas Masks § 84.1139 Air velocity and noise levels; hoods and helmets; minimum requirements. Noise levels generated by the respirator will be measured inside the hood or...

  5. 42 CFR 84.202 - Air velocity and noise levels; hoods and helmets; minimum requirements.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 42 Public Health 1 2010-10-01 2010-10-01 false Air velocity and noise levels; hoods and helmets... PROTECTIVE DEVICES Chemical Cartridge Respirators § 84.202 Air velocity and noise levels; hoods and helmets; minimum requirements. Noise levels generated by the respirator will be measured inside the hood or...

  6. 42 CFR 84.202 - Air velocity and noise levels; hoods and helmets; minimum requirements.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 42 Public Health 1 2014-10-01 2014-10-01 false Air velocity and noise levels; hoods and helmets... PROTECTIVE DEVICES Chemical Cartridge Respirators § 84.202 Air velocity and noise levels; hoods and helmets; minimum requirements. Noise levels generated by the respirator will be measured inside the hood or...

  7. 42 CFR 84.1139 - Air velocity and noise levels; hoods and helmets; minimum requirements.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 42 Public Health 1 2012-10-01 2012-10-01 false Air velocity and noise levels; hoods and helmets... Efficiency Respirators and Combination Gas Masks § 84.1139 Air velocity and noise levels; hoods and helmets; minimum requirements. Noise levels generated by the respirator will be measured inside the hood or...

  8. An Excel™-VBA programme for the analysis of current velocity profiles

    NASA Astrophysics Data System (ADS)

    Le Roux, J. P.; Brodalka, M.

    2004-10-01

    VPA is an Excel spreadsheet to facilitate the analysis of current velocity profiles and its application to sediment transport studies in steady, uniform, open-channel flows. The program requires input values such as the water temperature (from which the density and dynamic viscosity are calculated), the channel depth and slope, current velocities as measured at different heights above the bed, bedform length and height, as well as the sediment density and median size. The latter can be provided as sieve diameters, fall diameters or as phi values. The velocity profiles are plotted on two graphs, one being a traditional plot of velocity versus height or distance from the bed and the other comparing the observed profile with theoretical profiles for smooth, transitional and rough boundary conditions. VBA macros are provided to clear the spreadsheet before new profiles are analysed, update the formulas, straighten out the velocity profiles, calculate the shear velocity, and save the data on a separate sheet for further analysis. The programme is applied to a new and more accurate method to determine the shear velocity, which can be used to predict the bedload discharge over plane beds and is also incorporated into a dimensionally correct suspended load transport equation combining the parameters most important in sediment transport. A dimensionally correct bedload discharge equation based upon the mean excess flow velocity is also proposed for plane beds, ripples and dunes.

  9. Reconstruction of velocity profiles in axisymmetric and asymmetric flows using an electromagnetic flow meter

    NASA Astrophysics Data System (ADS)

    Kollár, László E.; Lucas, Gary P.; Meng, Yiqing

    2015-05-01

    An analytical method that was developed formerly for the reconstruction of velocity profiles in asymmetric flows is improved to be applicable for both axisymmetric and asymmetric flows. The method is implemented in Matlab, and predicts the velocity profile from measured electrical potential distributions obtained around the boundary of a multi-electrode electromagnetic flow meter (EMFM). Potential distributions are measured in uniform and non-uniform magnetic fields, and the velocity is assumed as a sum of axisymmetric and polynomial components. The procedure requires three steps. First, the discrete Fourier transform (DFT) is applied to the potential distribution obtained in a uniform magnetic field. Since the direction of polynomial components of order greater than two in the plane of the pipe cross section is not unique multiple solutions exist, therefore all possible polynomial velocity profiles are determined. Then, the DFT is applied to the potential distribution obtained in a specific non-uniform magnetic field, and used to calculate the exponent in a power-law representation of the axisymmetric component. Finally, the potential distribution in the non-uniform magnetic field is calculated for all of the possible velocity profile solutions using weight values, and the velocity profile with the calculated potential distribution which is closest to the measured one provides the optimum solution. The method is validated by reconstructing two quartic velocity profiles, one of which includes an axisymmetric component. The potential distributions are obtained from simulations using COMSOL Multiphysics where a model of the EMFM is constructed. The reconstructed velocity profiles show satisfactory agreement with the input velocity profiles. The main benefits of the method described in this paper are that it provides a velocity distribution in the circular cross section of a pipe as an analytical function of the spatial coordinates which is suitable for both

  10. On the Positive Bias of Peak Horizontal Velocity from an Idealized Doppler Profiler

    NASA Technical Reports Server (NTRS)

    Short, David A.; Merceret, Francis J.

    2004-01-01

    In the presence of 3-D turbulence, peak horizontal velocity estimates from an idealized Doppler profiler are found to be positively biased due to an incomplete specification of the vertical velocity field. The magnitude of the bias was estimated by assuming that the vertical and horizontal velocities can be separated into average and perturbation values and that the vertical and horizontal velocity perturbations are normally distributed. Under these assumptions, properties of the Type-I Extreme Value Distribution for maxima, known as the Gumbel distribution, can be used to obtain an analytical solution of the bias. The bias depends on geometric properties of the profiler configuration, the variance in the horizontal velocity, and the unresolved variance in the vertical velocity. When these variances are normalized by the average horizontal velocity, the bias can be mapped as a simple function of the normalized variances.

  11. Near-wall velocity profile measurement for nanofluids

    NASA Astrophysics Data System (ADS)

    Kanjirakat, Anoop; Sadr, Reza

    2016-01-01

    We perform near-wall velocity measurements of a SiO2-water nanofluid inside a microchannel. Nanoparticle image velocimetry measurements at three visible depths within 500 nm of the wall are conducted. We evaluate the optical properties of the nanofluid and their effect on the measurement technique. The results indicate that the small effect of the nanoparticles on the optical properties of the suspension have a negligible effect on the measurement technique. Our measurements show an increase in nanofluid velocity gradients near the walls, with no measurable slip, relative to the equivalent basefluid flow. We conjecture that particle migration induced by shear may have caused this increase. The effect of this increase in the measured near wall velocity gradient has implications on the viscosity measurement for these fluids.

  12. Prediction of inverted velocity profile for gas flow in nanochannel

    NASA Astrophysics Data System (ADS)

    Zhang, T. T.; Ren, Y. R.

    2014-11-01

    Velocity inversion is an interesting phenomenon of nanoscale which means that the velocity near the wall is greater than that of center. To solve this problem, fluid flow in nanochannel attracts more attention in recent years. The physical model of gas flow in two-dimensional nanochannel was established here. To describe the process with conventional control equations, Navier-Stokes equations combined with high-order accurate slip boundary conditions was used as mathematical model. With the introduction of new dimensionless variables, the problem was reduced to an ordinary differential equation. Then it was analytically solved and investigated using homotopy analysis method (HAM). The results were verified by comparing with other available experiment data. Result shows that the proposed method could predict velocity phenomenon.

  13. Major Upgrades to the AIRS Version-6 Ozone Profile Methodology

    NASA Technical Reports Server (NTRS)

    Susskind, Joel; Blaisdell, John; Iredell, Lena

    2015-01-01

    This research is a continuation of part of what was shown at the last AIRS Science Team Meeting in the talk Improved Water Vapor and Ozone Profiles in SRT AIRS Version-6.X and the AIRS February 11, 2015 NetMeeting Further improvements in water vapor and ozone profiles compared to Version-6.AIRS Version-6 was finalized in late 2012 and is now operational. Version-6 contained many significant improvements in retrieval methodology compared to Version-5. However, Version-6 retrieval methodology used for the water vapor profile q(p) and ozone profile O3(p) retrievals is basically unchanged from Version-5, or even from Version-4. Subsequent research has made significant improvements in both water vapor and O3 profiles compared to Version-6. This talk will concentrate on O3 profile retrievals. Improvements in water vapor profile retrievals are given in a separate presentation.

  14. Impact of air velocity, temperature, humidity, and air on long-term voc emissions from building products

    NASA Astrophysics Data System (ADS)

    Wolkoff, Peder

    The emissions of two volatile organic compounds (VOCs) of concern from five building products (BPs) were measured in the field and laboratory emission cell (FLEC) up to 250 d. The BPs (VOCs selected on the basis of abundance and low human odor thresholds) were: nylon carpet with latex backing (2-ethylhexanol, 4-phenylcyclohexene), PVC flooring (2-ethylhexanol, phenol), floor varnish on pretreated beechwood parquet (butyl acetate, N-methylpyrrolidone), sealant (hexane, dimethyloctanols), and waterborne wall paint on gypsum board (1,2-propandiol, Texanol). Ten different climate conditions were tested: four different air velocities from ca. 1 cm s -1 to ca. 9 cm s -1, three different temperatures (23, 35, and 60°C), two different relative humidities (0% and 50% RH), and pure nitrogen instead of clean air supply. Additionally, two sample specimen and two different batches were compared for repeatability and homogeneity. The VOCs were sampled on Tenax TA and determined by thermal desorption and gas chromatography (FID). Quantification was carried out by individual calibration of each VOC of concern. Concentration/time profiles of the selected VOCs (i.e. their concentration decay curves over time) in a standard room were used for comparison. Primary source emissions were not affected by the air velocity after a few days to any great extent. Both the temperature and relative humidity affected the emission rates, but depended strongly on the type of BP and type of VOC. Secondary (oxidative) source emissions were only observed for the PVC and for dimethyloctanols from the sealant. The time to reach a given concentration (emission rate) appears to be a good approach for future interlaboratory comparisons of BP's VOC emissions.

  15. Turbulence velocity profiling for high sensitivity and vertical-resolution atmospheric characterization with Stereo-SCIDAR

    NASA Astrophysics Data System (ADS)

    Osborn, J.; Butterley, T.; Townson, M. J.; Reeves, A. P.; Morris, T. J.; Wilson, R. W.

    2017-02-01

    As telescopes become larger, into the era of ˜40 m Extremely Large Telescopes, the high-resolution vertical profile of the optical turbulence strength is critical for the validation, optimization and operation of optical systems. The velocity of atmospheric optical turbulence is an important parameter for several applications including astronomical adaptive optics systems. Here, we compare the vertical profile of the velocity of the atmospheric wind above La Palma by means of a comparison of Stereo-SCIntillation Detection And Ranging (Stereo-SCIDAR) with the Global Forecast System models and nearby balloon-borne radiosondes. We use these data to validate the automated optical turbulence velocity identification from the Stereo-SCIDAR instrument mounted on the 2.5 m Isaac Newton Telescope, La Palma. By comparing these data we infer that the turbulence velocity and the wind velocity are consistent and that the automated turbulence velocity identification of the Stereo-SCIDAR is precise. The turbulence velocities can be used to increase the sensitivity of the turbulence strength profiles, as weaker turbulence that may be misinterpreted as noise can be detected with a velocity vector. The turbulence velocities can also be used to increase the altitude resolution of a detected layer, as the altitude of the velocity vectors can be identified to a greater precision than the native resolution of the system. We also show examples of complex velocity structure within a turbulent layer caused by wind shear at the interface of atmospheric zones.

  16. Calibration of a system for measuring low air flow velocity in a wind tunnel

    NASA Astrophysics Data System (ADS)

    Krach, Andrzej; Kruczkowski, Janusz

    2016-08-01

    This article presents the calibration of a system for measuring air flow velocity in a wind tunnel with a multiple-hole orifice. The comparative method was applied for the calibration. The method consists in equalising the air flow velocity in a test section of the tunnel with that of the hot-wire anemometer probe which should then read zero value. The hot-wire anemometer probe moves reciprocally in the tunnel test section with a constant velocity, aligned and opposite to the air velocity. Air velocity in the tunnel test section is adjusted so that the minimum values of a periodic hot-wire anemometer signal displayed on an oscilloscope screen reach the lowest position (the minimum method). A sinusoidal component can be superimposed to the probe constant velocity. Then, the air flow velocity in the tunnel test section is adjusted so that, when the probe moves in the direction of air flow, only the second harmonic of the periodically variable velocity superimposed on the constant velocity (second harmonic method) remains at the output of the low-pass filter to which the hot-wire anemometer signal, displayed on the oscilloscope screen, is supplied. The velocity of the uniform motion of the hot-wire anemometer probe is measured with a magnetic linear encoder. The calibration of the system for the measurement of low air velocities in the wind tunnel was performed in the following steps: 1. Calibration of the linear encoder for the measurement of the uniform motion velocity of the hot-wire anemometer probe in the test section of the tunnel. 2. Calibration of the system for measurement of low air velocities with a multiple-hole orifice for the velocities of 0.1 and 0.25 m s-1: - (a) measurement of the probe movement velocity setting; - (b) measurement of air velocity in the tunnel test section with comparison according to the second harmonic method; - (c) measurement of air velocity in the tunnel with comparison according to the minimum method. The calibration

  17. The Effect of Solid Admixtures on the Velocity of Motion of a Free Dusty Air Jet

    NASA Technical Reports Server (NTRS)

    Chernov, A. P.

    1957-01-01

    In dusty air flows occurring in industrial practice in transport by air pressure of friable materials, in the drying, annealing, and so forth, of a pulverized solid mass in suspension, and in other processes, the concentration of solid particles usually has a magnitude of the order of 1 kg per 1 kg of air. At such a concentration, the ratio of the volume of the particles to the volume of the air is small (less than one-thousandth part). However, regardless of this, the presence of a solid admixture manifests itself in the rules for the velocity distribution of the air in a dusty air flow. As a result, the rules of velocity change are different for clean and for dusty air flows. The estimation of the influence of the admixture on the velocity of the motion of the flow presents a definitive interest. One of the attempts to estimate that influence on the axial velocity of a free axially symmetrical jet with admixtures was made by Abramovich. Abramovich assumed beforehand that the fine particles of the admixture in the jet are subject to the motion of the air (that is, that the velocity of the admixture is approximately equal to the local velocity of the air); he then took as the basis of his considerations, in solving the problem, the condition that the amount of motion of the two-phase jet must be constant.

  18. Evaluation of 5-cm Agent Fate Wind Tunnel Velocity Profiles

    DTIC Science & Technology

    2007-09-01

    concentration at the sessile drop in the evaporation case. Such a simulation has the advantages that the heat transfer rate (analogous to evaporation rate) can...a simple two-dimensional problem of evaporation into a laminar Couette flow was investigated 6. This represents the sessile drop condition present...agreement is in establishing a quantitative criterion. For the small sessile drops being considered here, the friction velocity, u1, is the most important

  19. Velocity profiles of high-excitation molecular hydrogen lines

    NASA Technical Reports Server (NTRS)

    Moorhouse, A.; Brand, P. W. J. L.; Geballe, T. R.; Burton, M. G.

    1990-01-01

    Profiles of three lines of molecular hydrogen near 2.2 microns, originating from widely spaced energy levels, have been measured at a resolution of 32 km/s at Peak 1 in the Orion molecular outflow. The three lines, 1 - 0 S(1), 2 - 1 S(1), and 3 - 2 S(3), are found to have identical profiles. This result rules out any significant contribution to the population of the higher energy levels of molecular hydrogen at Peak 1 by fluorescence, and is generally consistent with emission from multiple J-type shocks.

  20. Scanning laser Doppler Technique for velocity profile sensing on a moving surface.

    PubMed

    Sriram, P; Hanagud, S; Craig, J; Komerath, N M

    1990-06-01

    A scanning laser Doppler technique based on Chebyshev demodulation has been developed for the rapid measurement of spatially distributed velocity profiles. Scan frequencies up to 100 Hz can be used over scan lengths up to 270 mm. The Doppler signals are processed in the conventional manner using a frequency counter. The analog velocity output from the counter is post-processed to obtain the velocity profile. The Chebyshev demodulation post-processing technique for processing the velocity signals from solid surfaces has been introduced. The data processing technique directly yields the spatial velocity distribution in approximate functional form through frequency domain analysis of the scanning LDV velocity output. Results from a rotating disk setup are presented to illustrate the concept.

  1. Brain strain uncertainty due to shape variation in and simplification of head angular velocity profiles.

    PubMed

    Zhao, Wei; Ji, Songbai

    2017-04-01

    Head angular velocity, instead of acceleration, is more predictive of brain strains. Surprisingly, no study exists that investigates how shape variation in angular velocity profiles affects brain strains, beyond characteristics such as peak magnitude and impulse duration. In this study, we evaluated brain strain uncertainty due to variation in angular velocity profiles and further compared with that resulting from simplifying the profiles into idealized shapes. To do so, we used reconstructed head impacts from American National Football League for shape extraction and simulated head uniaxial coronal rotations from onset to full stop. The velocity profiles were scaled to maintain an identical peak velocity magnitude and duration in order to isolate the shape for investigation. Element-wise peak maximum principal strains from 44 selected impacts were obtained. We found that the shape of angular velocity profile could significantly affect brain strain magnitude (e.g., percentage difference of 4.29-17.89 % in the whole brain relative to the group average, with cumulative strain damage measure (CSDM) uncertainty range of 23.9 %) but not pattern (correlation coefficient of 0.94-0.99). Strain differences resulting from simplifying angular velocity profiles into idealized shapes were largely within the range due to shape variation, in both percentage difference and CSDM (signed difference of 3.91 % on average, with a typical range of 0-6 %). These findings provide important insight into the uncertainty or confidence in the performance of kinematics-based injury metrics. More importantly, they suggest the feasibility to simplify head angular velocity profiles into idealized shapes, at least within the confinements of the profiles evaluated, to enable real-time strain estimation via pre-computation in the future.

  2. The cavitation induced by a rapid change of velocity profile

    NASA Astrophysics Data System (ADS)

    Olšiak, Róbert; Csuka, Zoltán; Fuszko, Zoltán

    2016-06-01

    The paper deals with the theory of cavitation flow near the high-speed rotary surface. For this purpose, a spatial model of two cylindrical surfaces imposed concentrically was designed. In the narrow gap between two cylindrical surfaces the temperature, density and viscosity of liquid are constant. Shear stress is induced by the high-speed rotary motion of the inner cylinder. In this case: velocity and pressure fields are changed. Due to the pressure drop between the cylinders there is a precondition to the formation of cavitation zones at the point of the lowest static pressure. This phenomenon is simulated via CFD methods.

  3. Velocity and pressure distribution behind bodies in an air current

    NASA Technical Reports Server (NTRS)

    Betz, A

    1924-01-01

    The following experiments on the air flow behind bodies were made for the purpose of assisting in the explanation of the phenomena connected with air resistance. The first two series of experiments dealt with the phenomena behind a cylinder. The third series of experiments was carried out behind a streamlined strut.

  4. Spatially and Temporally Resolved Measurements of Velocity in a H2-air Combustion-Heated Supersonic Jet

    NASA Technical Reports Server (NTRS)

    Bivolaru, Daniel; Cutler, Andrew D.; Danehy, Paul M.; Gaffney, Richard L.; Baurle, Robert a.

    2009-01-01

    This paper presents simultaneous measurements at multiple points of two orthogonal components of flow velocity using a single-shot interferometric Rayleigh scattering (IRS) technique. The measurements are performed on a large-scale Mach 1.6 (Mach 5.5 enthalpy) H2-air combustion jet during the 2007 test campaign in the Direct Connect Supersonic Combustion Test facility at NASA Langley Research Center. The measurements are performed simultaneously with CARS (Coherent Anti-stokes Raman Spectroscopy) using a combined CARS-IRS instrument with a common path 9-nanosecond pulsed, injection-seeded, 532-nm Nd:YAG laser probe pulse. The paper summarizes the measurements of velocities along the core of the vitiated air flow as well as two radial profiles. The average velocity measurement near the centerline at the closest point from the nozzle exit compares favorably with the CFD calculations using the VULCAN code. Further downstream, the measured axial velocity shows overall higher values than predicted with a trend of convergence at further distances. Larger discrepancies are shown in the radial profiles.

  5. Turbulent boundary-layer velocity profiles on a nonadiabatic at Mach number 6.5

    NASA Technical Reports Server (NTRS)

    Keener, E. R.; Hopkins, E. J.

    1972-01-01

    Velocity profiles were obtained from pitot-pressure and total-temperature measurements within a turbulent boundary layer on a large sharp-edged flat plate. Momentum-thickness Reynolds number ranged from 2590 to 8860 and wall-to-adiabatic-wall temperature ratios ranged from 0.3 to 0.5. Measurements were made both with and without boundary layer trips. Five methods are evaluated for correlating the measured velocity profiles with the incompressible law-of-the-wall and the velocity defect law. The mixing-length generalization of Van Driest gives the best correlation.

  6. Effect of Diffuser Design, Diffuser-exit Velocity Profile and Fuel Distribution on Altitude Performance of Several Afterburner Configurations

    NASA Technical Reports Server (NTRS)

    Conrad, E William; Schultz, Frederick W; Usow, Karl H

    1953-01-01

    An investigation was conducted in the NACA Lewis altitude wind tunnel to improve the altitude performance and operational characteristics of an afterburner primarily by modifying the diffuser-exit velocity profile by changes in diffuser design and by changing the fuel distribution and the flame holder. Twenty configurations, consisting of combinations of six diffuser geometries, six flame-holder types, and twelve fuel systems, were investigated. Data were obtained over a range of afterburner fuel-air ratios at diffuser-inlet total pressures from 2750 to 620 pounds per square foot. Changes in fuel distribution affected the fuel-air ratio at which peak combustion efficiency occurred as well as the efficiency level. Screeching combustion, which was most prevalent at low altitudes and medium-to-high fuel-air ratios, imposed a restriction on the operable range of a number of configurations.

  7. On Using Shaped Honeycombs for Experimental Generation of Arbitrary Velocity Profiles in Test Facilities

    NASA Astrophysics Data System (ADS)

    Safaripour, Alireza; Olson, David; Naguib, Ahmed; Koochesfahani, Manoochehr

    2016-11-01

    It is common to use a uniform approach flow in the study of most problems in aerodynamics. Motivated by situations where the approach flow is not uniform, the focus of the current work is on the experimental generation of arbitrary velocity profiles in a flow facility (water tunnel) using the shaped honeycomb technique originally proposed by Kotansky (1966). Employing further refinement of this approach, multiple honeycomb devices are designed and fabricated to produce prescribed velocity profiles. The performance of these devices is assessed in terms of their agreement with the desired velocity profiles and the level of turbulence they produce. Single-component molecular tagging velocimetry (1c-MTV) is used to characterize the resulting mean and fluctuating streamwise velocity profiles and their streamwise development. The shaped honeycomb technique is shown to be effective in producing the desired velocity profiles with high fidelity while maintaining velocity fluctuations level at or below that of the freestream prior to installation of the devices. This work was supported by AFOSR Award Number FA9550-15-1-0224.

  8. Jet Velocity Profile Effects on Spray Characteristics of Impinging Jets at High Reynolds and Weber Numbers

    NASA Astrophysics Data System (ADS)

    Rodrigues, Neil S.; Kulkarni, Varun; Sojka, Paul E.

    2014-11-01

    While like-on-like doublet impinging jet atomization has been extensively studied in the literature, there is poor agreement between experimentally observed spray characteristics and theoretical predictions (Ryan et al. 1995, Anderson et al. 2006). Recent works (Bremond and Villermaux 2006, Choo and Kang 2007) have introduced a non-uniform jet velocity profile, which lead to a deviation from the standard assumptions for the sheet velocity and the sheet thickness parameter. These works have assumed a parabolic profile to serve as another limit to the traditional uniform jet velocity profile assumption. Incorporating a non-uniform jet velocity profile results in the sheet velocity and the sheet thickness parameter depending on the sheet azimuthal angle. In this work, the 1/7th power-law turbulent velocity profile is assumed to provide a closer match to the flow behavior of jets at high Reynolds and Weber numbers, which correspond to the impact wave regime. Predictions for the maximum wavelength, sheet breakup length, ligament diameter, and drop diameter are compared with experimental observations. The results demonstrate better agreement between experimentally measured values and predictions, compared to previous models. U.S. Army Research Office under the Multi-University Research Initiative Grant Number W911NF-08-1-0171.

  9. Effect of flow distributors on uniformity of velocity profile in a baghouse.

    PubMed

    Chen, Chi-Jen; Cheng, Man-Ting

    2005-07-01

    In recent years, the utility industry has turned to baghouses as an alternative technology for particulate emission control from pulverized-coal-fired power plants. One of the more significant issues is to improve poor gas distribution that causes bag failures in baghouse operation. Bag failures during operation are almost impossible to prevent, but proper flow design can help in their prevention. This study investigated vertical velocity profiles below the bags in a baghouse (the hopper region) to determine whether flow could be improved with the installation of flow distributors in the hopper region. Three types of flow distributors were used to improve flow distribution and were compared with the original baghouse without flow distributors. Velocity profiles were measured by a hot-wire anemometer at an inlet velocity of 18 m/sec. Uniformity of flow distribution was calculated by the uniformity value U for the velocity profile of each flow distributor. Experimental results showed that the velocity profile of the empty configuration (without flow distributors) was poor because the uniformity value was 2.048. The uniformity values of type 1 (flow distributor with three vertical vanes), type 2 (flow distributor with one vertical and one inclined vane), and type 3 (flow distributor with two inclined vanes) configurations were reduced to 1.051, 0.617, and 0.526, respectively. These results indicate that the flow distributors designed in this study made significant improvements in the velocity profile of a baghouse, with the type 3 configuration having the best performance.

  10. Molecular dynamic simulation of Ar-Kr mixture across a rough walled nanochannel: Velocity & temperature profiles

    NASA Astrophysics Data System (ADS)

    Pooja, Pathania, Y.; Ahluwalia, P. K.

    2015-05-01

    This paper presents the results from a molecular dynamics simulation of mixture of argon and krypton in the Poiseuille flow across a rough walled nanochannel. The roughness effect on liquid nanoflows has recently drawn attention The computational software used for carrying out the molecular dynamics simulations is LAMMPS. The fluid flow takes place between two parallel plates and is bounded by horizontal rough walls in one direction and periodic boundary conditions are imposed in the other two directions. Each fluid atom interacts with other fluid atoms and wall atoms through Leenard-Jones (LJ) potential with a cut off distance of 5.0. To derive the flow a constant force is applied whose value is varied from 0.1 to 0.3 and velocity profiles and temperature profiles are noted for these values of forces. The velocity profile and temperature profiles are also looked at different channel widths of nanochannel and at different densities of mixture. The velocity profile and temperature profile of rough walled nanochannel are compared with that of smooth walled nanochannel and it is concluded that mean velocity increases with increase in channel width, force applied and decrease in density also with introduction of roughness in the walls of nanochannel mean velocity again increases and results also agree with the analytical solution of a Poiseuille flow.

  11. Velocity, temperature, and electrical conductivity profiles in hydrogen-oxygen MHD duct flows

    NASA Technical Reports Server (NTRS)

    Greywall, M. S.; Pian, C. C. P.

    1978-01-01

    Two-dimensional duct flow computations for radial distributions of velocity, temperature, and electrical conductivity are reported. Calculations were carried out for the flow conditions representative of a hydrogen-oxygen combustion driven MHD duct. Results are presented for: profiles of developing flow in a smooth duct, and for profiles of fully developed pipe flow with a specified streamwise shear stress distribution. The predicted temperature and electrical conductivity profiles for the developing flows compare well with available experimental data.

  12. Development of ultrasonic pulse-train Doppler method for velocity profile and flowrate measurement

    NASA Astrophysics Data System (ADS)

    Wada, Sanehiro; Furuichi, Noriyuki; Shimada, Takashi

    2016-11-01

    We present a novel technique for measuring the velocity profile and flowrate in a pipe. This method, named the ultrasonic pulse-train Doppler method (UPTD), has the advantages of expanding the velocity range and setting the smaller measurement volume with low calculation and instrument costs in comparison with the conventional ultrasonic pulse Doppler method. The conventional method has limited measurement of the velocity range due to the Nyquist sampling theorem. In addition, previous reports indicate that a smaller measurement volume increases the accuracy of the measurement. In consideration of the application of the conventional method to actual flow fields, such as industrial facilities and power plants, the issues of velocity range and measurement volume are important. The UPTD algorithm, which exploits two pulses of ultrasound with a short interval and envelope detection, is proposed. Velocity profiles calculated by this algorithm were examined through simulations and excellent agreement was found in all cases. The influence of the signal-to-noise ratio (SNR) on the algorithm was also estimated. The result indicates that UPTD can measure velocity profiles with high accuracy, even under a small SNR. Experimental measurements were conducted and the results were evaluated at the national standard calibration facility of water flowrate in Japan. Every detected signal forms a set of two pulses and the enveloped line can be observed clearly. The results show that UPTD can measure the velocity profiles over the pipe diameter, even if the velocities exceed the measurable velocity range. The measured flowrates were under 0.6% and the standard deviations for all flowrate conditions were within  ±0.38%, which is the uncertainty of the flowrate measurement estimated in the previous report. In conclusion, UPTD provides superior accuracy and expansion of the velocity range.

  13. Assessment of air velocity sensors for use in animal produciton facilities

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ventilation is an integral part of thermal environment control in animal production facilities. Accurately measuring the air velocity distribution within these facilities is cumbersome using the traverse method and a distributed velocity measurement system would reduce the time necessary to perform ...

  14. Simultaneous Measurement of Air Temperature and Humidity Based on Sound Velocity and Attenuation Using Ultrasonic Probe

    NASA Astrophysics Data System (ADS)

    Motegi, Takahiro; Mizutani, Koichi; Wakatsuki, Naoto

    2013-07-01

    In this paper, an acoustic technique for air temperature and humidity measurement in moist air is described. The previous ultrasonic probe can enable the estimation of temperature from sound velocity in dry air by making use of the relationship between sound velocity and temperature. However, temperature measurement using the previous ultrasonic probe is not suitable in moist air because sound velocity also depends on humidity, and the temperature estimated from the sound velocity measured in moist air must be adjusted. Moreover, a method of humidity measurement by using only an ultrasonic probe has not been established. Thus, we focus on sound attenuation, which depends on temperature and humidity. Our proposed technique utilizes two parameters, sound velocity and attenuation, and can measure both temperature and humidity simultaneously. The acoustic technique for temperature and humidity measurement has the advantages that instantaneous temperature and humidity can be measured, and the measurement is not affected by thermal radiation because air itself is used as a sensing element. As an experiment, temperature and humidity are measured in a chamber, and compared with the reference values. The experimental results indicate the achievement of a practical temperature measurement accuracy of within +/-0.5 K in moist air, of which the temperature is 293-308 K and relative humidity (RH) is 50-90% RH, and the simultaneous measurement of temperature and humidity.

  15. Mass, velocity anisotropy, and pseudo phase-space density profiles of Abell 2142

    NASA Astrophysics Data System (ADS)

    Munari, E.; Biviano, A.; Mamon, G. A.

    2014-06-01

    Aims: We aim to compute the mass and velocity anisotropy profiles of Abell 2142 and, from there, the pseudo phase-space density profile Q(r) and the density slope - velocity anisotropy β - γ relation, and then to compare them with theoretical expectations. Methods: The mass profiles were obtained by using three techniques based on member galaxy kinematics, namely the caustic method, the method of dispersion-kurtosis, and MAMPOSSt. Through the inversion of the Jeans equation, it was possible to compute the velocity anisotropy profiles. Results: The mass profiles, as well as the virial values of mass and radius, computed with the different techniques agree with one another and with the estimates coming from X-ray and weak lensing studies. A combined mass profile is obtained by averaging the lensing, X-ray, and kinematics determinations. The cluster mass profile is well fitted by an NFW profile with c = 4.0 ± 0.5. The population of red and blue galaxies appear to have a different velocity anisotropy configuration, since red galaxies are almost isotropic, while blue galaxies are radially anisotropic, with a weak dependence on radius. The Q(r) profile for the red galaxy population agrees with the theoretical results found in cosmological simulations, suggesting that any bias, relative to the dark matter particles, in velocity dispersion of the red component is independent of radius. The β - γ relation for red galaxies matches the theoretical relation only in the inner region. The deviations might be due to the use of galaxies as tracers of the gravitational potential, unlike the non-collisional tracer used in the theoretical relation.

  16. Variation of velocity profile according to blood viscosity in a microfluidic channel

    NASA Astrophysics Data System (ADS)

    Yeom, Eunseop; Kang, Yang Jun; Lee, Sang-Joon

    2014-11-01

    The shear-thinning effect of blood flows is known to change blood viscosity. Since blood viscosity and motion of red blood cells (RBCs) are closely related, hemorheological variations have a strong influence on hemodynamic characteristics. Therefore, understanding on the relationship between the hemorheological and hemodynamic properties is importance for getting more detailed information on blood circulation in microvessels. In this study, the blood viscosity and velocity profiles in a microfluidic channel were systematically investigated. Rat blood was delivered in the microfluidic device which can measure blood viscosity by monitoring the flow-switching phenomenon. Velocity profiles of blood flows in the microchannel were measured by using a micro-particle image velocimetry (PIV) technique. Shape of velocity profiles measured at different flow rates was quantified by using a curve-fitting equation. It was observed that the shape of velocity profiles is highly correlated with blood viscosity. The study on the relation between blood viscosity and velocity profile would be helpful to understand the roles of hemorheological and hemodynamic properties in cardiovascular diseases. This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea Government (MSIP) (No. 2008-0061991).

  17. Effects of air velocity on laying hen production

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Thermal conditions play a major role in production efficiency in commercial poultry production. Mitigation of thermal stress can improve productivity, but must be achieved economically. Weather and system design can limit effectiveness of evaporative cooling and increased air movement has been sho...

  18. Evaluation of an Extended Autocorrelation Phase Estimator for Ultrasonic Velocity Profiles Using Nondestructive Testing Systems.

    PubMed

    Ofuchi, César Yutaka; Coutinho, Fabio Rizental; Neves, Flávio; de Arruda, Lucia Valéria Ramos; Morales, Rigoberto Eleazar Melgarejo

    2016-08-09

    In this paper the extended autocorrelation velocity estimator is evaluated and compared using a nondestructive ultrasonic device. For this purpose, three velocity estimators are evaluated and compared. The autocorrelation method (ACM) is the most used and well established in current ultrasonic velocity profiler technology, however, the technique suffers with phase aliasing (also known as the Nyquist limit) at higher velocities. The cross-correlation method (CCM) is also well known and does not suffer with phase aliasing as it relies on time shift measurements between emissions. The problem of this method is the large computational burden due to several required mathematical operations. Recently, an extended autocorrelation method (EAM) which combines both ACM and CCM was developed. The technique is not well known within the fluid engineering community, but it can measure velocities beyond the Nyquist limit without the ACM phase aliasing issues and with a lower computational cost than CCM. In this work, all three velocity estimation methods are used to measure a uniform flow of the liquid inside a controlled rotating cylinder. The root-mean-square deviation variation coefficient (CVRMSD) of the velocity estimate and the reference cylinder velocity was used to evaluate the three different methods. Results show that EAM correctly measures velocities below the Nyquist limit with less than 2% CVRMSD. Velocities beyond the Nyquist limit are only measured well by EAM and CCM, with the advantage of the former of being computationally 15 times faster. Furthermore, the maximum value of measurable velocity is also investigated considering the number of times the velocity surpasses the Nyquist limit. The combination of number of pulses and number of samples, which highly affects the results, are also studied in this work. Velocities up to six times the Nyquist limit could be measurable with CCM and EAM using a set of parameters as suggested in this work. The results validate

  19. Evaluation of an Extended Autocorrelation Phase Estimator for Ultrasonic Velocity Profiles Using Nondestructive Testing Systems

    PubMed Central

    Ofuchi, César Yutaka; Coutinho, Fabio Rizental; Neves, Flávio; de Arruda, Lucia Valéria Ramos; Morales, Rigoberto Eleazar Melgarejo

    2016-01-01

    In this paper the extended autocorrelation velocity estimator is evaluated and compared using a nondestructive ultrasonic device. For this purpose, three velocity estimators are evaluated and compared. The autocorrelation method (ACM) is the most used and well established in current ultrasonic velocity profiler technology, however, the technique suffers with phase aliasing (also known as the Nyquist limit) at higher velocities. The cross-correlation method (CCM) is also well known and does not suffer with phase aliasing as it relies on time shift measurements between emissions. The problem of this method is the large computational burden due to several required mathematical operations. Recently, an extended autocorrelation method (EAM) which combines both ACM and CCM was developed. The technique is not well known within the fluid engineering community, but it can measure velocities beyond the Nyquist limit without the ACM phase aliasing issues and with a lower computational cost than CCM. In this work, all three velocity estimation methods are used to measure a uniform flow of the liquid inside a controlled rotating cylinder. The root-mean-square deviation variation coefficient (CVRMSD) of the velocity estimate and the reference cylinder velocity was used to evaluate the three different methods. Results show that EAM correctly measures velocities below the Nyquist limit with less than 2% CVRMSD. Velocities beyond the Nyquist limit are only measured well by EAM and CCM, with the advantage of the former of being computationally 15 times faster. Furthermore, the maximum value of measurable velocity is also investigated considering the number of times the velocity surpasses the Nyquist limit. The combination of number of pulses and number of samples, which highly affects the results, are also studied in this work. Velocities up to six times the Nyquist limit could be measurable with CCM and EAM using a set of parameters as suggested in this work. The results validate

  20. Skin friction and velocity profile family for compressible turbulent boundary layers

    NASA Technical Reports Server (NTRS)

    Huang, P. G.; Bradshaw, P.; Coakley, T. J.

    1993-01-01

    The paper presents a general approach to constructing mean velocity profiles for compressible turbulent boundary layers with isothermal or adiabatic walls. The theory is based on a density-weighted transformation that allows the extension of the incompressible similarity laws of the wall to the compressible regions. The velocity profile family is compared to a range of experimental data, and excellent agreement is obtained. A self-consistent skin friction law, which satisfies the proposed velocity profile family, is derived and compared with the well-known Van Driest II theory for boundary layers in zero pressure gradient. The results are found to be at least as good as those obtained by using the Van Driest II transformation.

  1. Ultrasonic velocity profiling rheometry based on a widened circular Couette flow

    NASA Astrophysics Data System (ADS)

    Shiratori, Takahisa; Tasaka, Yuji; Oishi, Yoshihiko; Murai, Yuichi

    2015-08-01

    We propose a new rheometry for characterizing the rheological properties of fluids. The technique produces flow curves, which represent the relationship between the fluid shear rate and shear stress. Flow curves are obtained by measuring the circumferential velocity distribution of tested fluids in a circular Couette system, using an ultrasonic velocity profiling technique. By adopting a widened gap of concentric cylinders, a designed range of the shear rate is obtained so that velocity profile measurement along a single line directly acquires flow curves. To reduce the effect of ultrasonic noise on resultant flow curves, several fitting functions and variable transforms are examined to best approximate the velocity profile without introducing a priori rheological models. Silicone oil, polyacrylamide solution, and yogurt were used to evaluate the applicability of this technique. These substances are purposely targeted as examples of Newtonian fluids, shear thinning fluids, and opaque fluids with unknown rheological properties, respectively. We find that fourth-order Chebyshev polynomials provide the most accurate representation of flow curves in the context of model-free rheometry enabled by ultrasonic velocity profiling.

  2. Method of LSD profile asymmetry for estimating the center of mass velocities of pulsating stars

    NASA Astrophysics Data System (ADS)

    Britavskiy, Nikolay; Pancino, Elena; Romano, Donatella; Tsymbal, Vadim

    2015-08-01

    We present radial velocity analysis for 20 solar neighborhood RR Lyrae and 3 Population II Cepheids. High-resolution spectra were observed with either TNG/SARG or VLT/UVES over varying phases. To estimate the center of mass (barycentric) velocities of the program stars, we utilized two independent methods. First, the 'classic' method was employed, which is based on RR Lyrae radial velocity curve templates. Second, we provide the new method that used absorption line profile asymmetry to determine both the pulsation and the barycentric velocities even with a low number of high-resolution spectra and in cases where the phase of the observations is uncertain. This new method is based on a Least Squares Deconvolution (LSD) of the line profiles in order to analyze line asymmetry that occurs in the spectra of pulsating stars. By applying this method to our sample stars we attain accurate measurements (± 1 km/s) of the pulsation component of the radial velocity. This results in determination of the barycentric velocity to within 5 km/s even with a low number of high-resolution spectra. A detailed investigation of LSD profile asymmetry shows the variable nature of the project factor at different pulsation phases, which should be taken into account in the detailed spectroscopic analysis of pulsating stars.

  3. Method of LSD profile asymmetry for estimating the center of mass velocities of pulsating stars

    NASA Astrophysics Data System (ADS)

    Britavskiy, N.; Pancino, E.; Tsymbal, V.; Romano, D.; Cacciari, C.; Clementini, C.

    2016-05-01

    We present radial velocity analysis for 20 solar neighborhood RR Lyrae and 3 Population II Cepheids. High-resolution spectra were observed with either TNG/SARG or VLT/UVES over varying phases. To estimate the center of mass (barycentric) velocities of the program stars, we utilized two independent methods. First, the 'classic' method was employed, which is based on RR Lyrae radial velocity curve templates. Second, we provide the new method that used absorption line profile asymmetry to determine both the pulsation and the barycentric velocities even with a low number of high-resolution spectra and in cases where the phase of the observations is uncertain. This new method is based on a least squares deconvolution (LSD) of the line profiles in order to an- alyze line asymmetry that occurs in the spectra of pulsating stars. By applying this method to our sample stars we attain accurate measurements (+- 2 kms^-1) of the pulsation component of the radial velocity. This results in determination of the barycentric velocity to within 5 kms^-1 even with a low number of high- resolution spectra. A detailed investigation of LSD profile asymmetry shows the variable nature of the project factor at different pulsation phases, which should be taken into account in the detailed spectroscopic analysis of pulsating stars.

  4. Errors in acoustic doppler profiler velocity measurements caused by flow disturbance

    USGS Publications Warehouse

    Mueller, D.S.; Abad, J.D.; Garcia, C.M.; Gartner, J.W.; Garcia, M.H.; Oberg, K.A.

    2007-01-01

    Acoustic Doppler current profilers (ADCPs) are commonly used to measure streamflow and water velocities in rivers and streams. This paper presents laboratory, field, and numerical model evidence of errors in ADCP measurements caused by flow disturbance. A state-of-the-art three-dimensional computational fluid dynamic model is validated with and used to complement field and laboratory observations of flow disturbance and its effect on measured velocities. Results show that near the instrument, flow velocities measured by the ADCP are neither the undisturbed stream velocity nor the velocity of the flow field around the ADCP. The velocities measured by the ADCP are biased low due to the downward flow near the upstream face of the ADCP and upward recovering flow in the path of downstream transducer, which violate the flow homogeneity assumption used to transform beam velocities into Cartesian velocity components. The magnitude of the bias is dependent on the deployment configuration, the diameter of the instrument, and the approach velocity, and was observed to range from more than 25% at 5cm from the transducers to less than 1% at about 50cm from the transducers for the scenarios simulated. ?? 2007 ASCE.

  5. Velocity profiles, Reynolds stresses and bed roughness from an autonomous field deployed Acoustic Doppler Velocity Profiler in a mixed sediment tidal estuary

    NASA Astrophysics Data System (ADS)

    O'Boyle, Louise; Thorne, Peter; Cooke, Richard; Cohbed Team

    2014-05-01

    Estuaries are among some of the most important global landscapes in terms of population density, ecology and economy. Understanding the dynamics of these natural mixed sediment environments is of particular interest amid growing concerns over sea level rise, climate variations and estuarine response to these changes. Many predictors exist for bed form formation and sand transport in sandy coastal zones; however less work has been published on mixed sediments. This paper details a field study which forms part of the COHBED project aiming to increase understanding of bed forms in a biotic mixed sediment estuarine environment. The study was carried out in the Dee Estuary, in the eastern Irish Sea between England and Wales from the 21st May to 4th June 2013. A state of the art instrumentation frame, known as SEDbed, was deployed at three sites of differing sediment properties and biological makeup within the intertidal zone of the estuary. The SEDbed deployment consisted of a suite of optical and acoustic instrumentation, including an Acoustic Doppler Velocity Profiler (ADVP), Acoustic Doppler Velocimeter (ADV) and a three dimensional acoustic ripple profiler, 3D-ARP. Supplementary field samples and measurements were recorded alongside the frame during each deployment. This paper focuses on the use of new technological developments for the investigation of sediment dynamics. The hydrodynamics at each of the deployment sites are presented including centimetre resolution velocity profiles in the near bed region of the water column, obtained from the ADVP, which is presently the only autonomous field deployed coherent Doppler profiler . Based on these high resolution profiles variations in frictional velocity, bed shear stress and roughness length are calculated. Comparisons are made with theoretical models and with Reynolds stress values obtained from ADV data at a single point within the ADVP profile and from ADVP data itself. Predictions of bed roughness at each

  6. Re-evaluation of the central velocity-dispersion profile in NGC 6388

    NASA Astrophysics Data System (ADS)

    Lützgendorf, Nora; Gebhardt, Karl; Baumgardt, Holger; Noyola, Eva; Neumayer, Nadine; Kissler-Patig, Markus; de Zeeuw, Tim

    2015-09-01

    Context. The globular cluster NGC 6388 is one of the most massive clusters in our Milky Way and has been the subject of many studies. Recently, two independent groups found very different results when measuring its central velocity-dispersion profile with different methods. While we found a rising profile and a high central velocity dispersion (23.3 km s-1), measurements obtained by Lanzoni et al. (2013, ApJ, 769, 107) showed a value lower by 40%. The value of the central velocity dispersion has a serious effect on the mass and possible presence of an intermediate-mass black hole at the center of NGC 6388. Aims: The goal of this paper is to quantify the biases arising from measuring velocity dispersions from individual extracted stellar velocities versus the line broadening measurements of the integrated light using new tools to simulate realistic observations made with integral field units (IFU). Methods: We used a photometric catalog of NGC 6388 to extract the positions and magnitudes from the brightest stars in the central three arcseconds of NGC 6388 and created a simulated SINFONI and ARGUS dataset. The IFU data cube was constructed with different observing conditions (i.e., Strehl ratios and seeing) reproducing the conditions reported for the original observations as closely as possible. In addition, we produced an N-body realization of a ~106 M⊙ stellar cluster with the same photometric properties as NGC 6388 to account for unresolved stars. Results: We find that the individual radial velocities, that is, the measurements from the simulated SINFONI data, are systematically biased towards lower velocity dispersions. The reason is that the velocities become biased toward the mean cluster velocity as a result of the wings in the point spread function of adaptive optics (AO) corrected data sets. This study shows that even with AO supported observations, individual radial velocities in crowded fields do not reproduce the true velocity distribution. The ARGUS

  7. Experimental analysis of the velocity field of the air flowing through the swirl diffusers

    NASA Astrophysics Data System (ADS)

    Jaszczur, M.; Branny, M.; Karch, M.; Borowski, M.

    2016-09-01

    The article presents the results of experimental studies of flow of air through diffusers. Presented laboratory model is a simplification of the real system and was made in a geometric scale 1:10. Simplifying refer both to the geometry of the object and conditions of air flow. The aim of the study is to determine the actual velocity fields of air flowing out of the swirl diffuser. The results obtained for the diffuser various settings are presented. We have tested various flow rates of air. Stereo Particle Image Velocimetry (SPIV) method was used to measure all velocity vector components. The experimental results allow to determine the actual penetration depth of the supply air into the room. This will allow for better definition of the conditions of ventilation in buildings.

  8. Velocity profiles inside volcanic clouds from three-dimensional scanning microwave dual-polarization Doppler radars

    NASA Astrophysics Data System (ADS)

    Montopoli, Mario

    2016-07-01

    In this work, velocity profiles within a volcanic tephra cloud obtained by dual-polarization Doppler radar acquisitions with three-dimensional (3-D) mechanical scanning capability are analyzed. A method for segmenting the radar volumes into three velocity regimes: vertical updraft, vertical fallout, and horizontal wind advection within a volcanic tephra cloud using dual-polarization Doppler radar moments is proposed. The horizontal and vertical velocity components within the regimes are retrieved using a novel procedure that makes assumptions concerning the characteristics of the winds inside these regimes. The vertical velocities retrieved are combined with 1-D simulations to derive additional parameters including particle fallout, mass flux, and particle sizes. The explosive event occurred on 23 November 2013 at the Mount Etna volcano (Sicily, Italy), is considered a demonstrative case in which to analyze the radar Doppler signal inside the tephra column. The X-band radar (3 cm wavelength) in the Catania, Italy, airport observed the 3-D scenes of the Etna tephra cloud ~32 km from the volcano vent every 10 min. From the radar-derived vertical velocity profiles of updraft, particle fallout, and horizontal transportation, an exit velocity of 150 m/s, mass flux rate of 1.37 • 107 kg/s, particle fallout velocity of 18 m/s, and diameters of precipitating tephra particles equal to 0.8 cm are estimated on average. These numbers are shown to be consistent with theoretical 1-D simulations of plume dynamics and local reports at the ground, respectively. A thickness of 3 ± 0.36 km for the downwind ash cloud is also inferred by differentiating the radar-derived cloud top and the height of transition between the convective and buoyancy regions, the latter being inferred by the estimated vertical updraft velocity profile. The unique nature of the case study as well as the novelty of the segmentation and retrieval methods presented potentially give new insights into the

  9. Inert gas influence on the laminar burning velocity of methane-air mixtures.

    PubMed

    Mitu, Maria; Giurcan, Venera; Razus, Domnina; Oancea, Dumitru

    2017-01-05

    Flame propagation was studied in methane-air-inert (He, Ar, N2 or CO2) mixtures with various initial pressures and compositions using pressure-time records obtained in a spherical vessel with central ignition. The laminar burning velocities of CH4-air and CH4-air-inert mixtures obtained from experimental p(t) records of the early stage of combustion were compared with literature data and with those obtained from numerical modeling of 1D flames. The overall reaction orders of methane oxidation were determined from the baric coefficients of the laminar burning velocities determined from power-law equations. For all mixtures, the adiabatic flames temperatures were computed, assuming that the chemical equilibrium is reached in the flame front. The overall activation energy for the propagation stage of the combustion process was determined from the temperature dependence of the laminar burning velocity.

  10. Influence of air velocity on the habit of ice crystal growth from the vapor

    NASA Technical Reports Server (NTRS)

    Keller, V. W.; Hallett, J.

    1982-01-01

    The effect of air velocity on the growth behavior of ice crystals growing from water vapor was investigated at temperatures between 0 and -35 C and at supersaturation levels ranging from 2 to 40 percent, using a laboratory chamber in which it was possible to make these variations. It was found that crystal growth was most sensitive to changes in the air velocity at temperatures near -4 C and -15 C where, near water saturation, the introduction of only a 5 cm/s air velocity induced skeletal transitions (columns to needles near -4 C and plates to dendrites near -15 C). The experiments provide conditions which simulate growth of ice crystals in the atmosphere, where crystal growth takes place at or somewhat below water saturation.

  11. A comparison between observed and analytical velocity dispersion profiles of 20 nearby galaxy clusters

    NASA Astrophysics Data System (ADS)

    Khan, Mohammad S.; Abdullah, Mohamed H.; Ali, Gamal B.

    2014-05-01

    We derive analytical expression for the velocity dispersion of galaxy clusters, using the statistical mechanical approach. We compare the observed velocity dispersion profiles for 20 nearby ( z≤0.1) galaxy clusters with the analytical ones. It is interesting to find that the analytical results closely match with the observed velocity dispersion profiles only if the presence of the diffuse matter in clusters is taken into consideration. This takes us to introduce a new approach to detect the ratio of diffuse mass, M diff , within a galaxy cluster. For the present sample, the ratio f= M diff / M, where M the cluster's total mass is found to has an average value of 45±12 %. This leads us to the result that nearly 45 % of the cluster mass is impeded outside the galaxies, while around 55 % of the cluster mass is settled in the galaxies.

  12. Comparing shear-wave velocity profiles inverted from multichannel surface wave with borehole measurements

    USGS Publications Warehouse

    Xia, J.; Miller, R.D.; Park, C.B.; Hunter, J.A.; Harris, J.B.; Ivanov, J.

    2002-01-01

    Recent field tests illustrate the accuracy and consistency of calculating near-surface shear (S)-wave velocities using multichannel analysis of surface waves (MASW). S-wave velocity profiles (S-wave velocity vs. depth) derived from MASW compared favorably to direct borehole measurements at sites in Kansas, British Columbia, and Wyoming. Effects of changing the total number of recording channels, sampling interval, source offset, and receiver spacing on the inverted S-wave velocity were studied at a test site in Lawrence, Kansas. On the average, the difference between MASW calculated Vs and borehole measured Vs in eight wells along the Fraser River in Vancouver, Canada was less than 15%. One of the eight wells was a blind test well with the calculated overall difference between MASW and borehole measurements less than 9%. No systematic differences were observed in derived Vs values from any of the eight test sites. Surface wave analysis performed on surface data from Wyoming provided S-wave velocities in near-surface materials. Velocity profiles from MASW were confirmed by measurements based on suspension log analysis. ?? 2002 Elsevier Science Ltd. All rights reserved.

  13. Vertical Profiling of Air Pollution at RAPCD

    NASA Technical Reports Server (NTRS)

    Newchurch, Michael J.; Fuller, Kirk A.; Bowdle, David A.; Johnson, Steven; Knupp, Kevin; Gillani, Noor; Biazar, Arastoo; Mcnider, Richard T.; Burris, John

    2004-01-01

    The interaction between local and regional pollution levels occurs at the interface of the Planetary Boundary Layer and the Free Troposphere. Measuring the vertical distribution of ozone, aerosols, and winds with high temporal and vertical resolution is essential to diagnose the nature of this interchange and ultimately for accurately forecasting ozone and aerosol pollution levels. The Regional Atmospheric Profiling Center for Discovery, RAPCD, was built and instrumented to address this critical issue. The ozone W DIAL lidar, Nd:YAG aerosol lidar, and 2.1 micron Doppler wind lidar, along with balloon- borne ECC ozonesondes form the core of the W C D instrumentation for addressing this problem. Instrumentation in the associated Mobile Integrated Profiling (MIPS) laboratory includes 91 5Mhz profiler, sodar, and ceilometer. The collocated Applied particle Optics and Radiometry (ApOR) laboratory hosts an FTIR along with MOUDI and optical particle counters. With MODELS-3 analysis by colleagues in the National Space Science and Technology Center on the UAH campus and the co- located National Weather Service Forecasting Office in Huntsville, AL we are developing a unique facility for advancing the state of the science of pollution forecasting.

  14. Effect of mean-velocity profile shapes on sound transmission through two-dimensional ducts

    NASA Technical Reports Server (NTRS)

    Hayfeh, A. H.; Kaiser, J. E.; Shaker, B. S.

    1974-01-01

    Acoustic propagation through a lined two-dimensional duct is examined in order to assess the influence of the shape of the mean-velocity profile on the attenuation rate. Five mean-velocity profiles are considered: linear, parabolic, Pohlhausen, 1/7th power law with a linear sub-layer, and linear with slip at the wall. It is shown that when the attenuation rate is tabulated as a function of the boundary-layer thickness, as is usually done, substantially different results are obtained from the several mean profiles. However, when the displacement thickness is used, a considerable collapse is achieved in the attenuation curves that are obtained from the various profiles. For downstream propagation, all profiles produce essentially the same results over a reasonable range of boundary-layer thickness. However, for many cases of upstream propagation, the results from the 'turbulent' boundary-layer profiles differ significantly from the results of the other profiles even when compared on the basis of displacement thickness.

  15. Neural-network simulation of tonal categorization based on F0 velocity profiles

    NASA Astrophysics Data System (ADS)

    Gauthier, Bruno; Shi, Rushen; Xu, Yi; Proulx, Robert

    2005-04-01

    Perception studies have shown that by the age of six months, infants show particular response patterns to tones in their native language. The present study focuses on how infants might develop lexical tones in Man- darin. F0 is generally considered the main cue in tone perception. However, F0 patterns in connected speech display extensive contextual variability. Since speech input to infants consists mainly of multi-word utterances, tone learning must involve processes that can effectively resolve variability. In this study we explore the Target Approximation model (Xu and Wang, 2001) which characterizes surface F0 as asymptotic movements toward underlying pitch targets defined as simple linear functions. The model predicts that it is possible to infer underlying pitch targets from the manners of F0 movements. Using production data of three of the speakers from Xu (1997), we trained a self-organizing neural network with both F0 profiles and F0 velocity profiles as input. In the testing phase, velocity profiles yielded far superior categorization than F0 profiles. The results confirm that velocity profiles can effectively abstract away from surface variability and directly reflect underlying articulatory goals. The finding thus points to one way through which infants can successfully derive at phonetic categories from adult speech.

  16. Measurement of temperature and velocity fields in a convective fluid flow in air using schlieren images.

    PubMed

    Martínez-González, A; Moreno-Hernández, D; Guerrero-Viramontes, J A

    2013-08-01

    A convective fluid flow in air could be regulated if the physical process were better understood. Temperature and velocity measurements are required in order to obtain a proper characterization of a convective fluid flow. In this study, we show that a classical schlieren system can be used for simultaneous measurements of temperature and velocity in a convective fluid flow in air. The schlieren technique allows measurement of the average fluid temperature and velocity integrated in the direction of the test beam. Therefore, in our experiments we considered surfaces with isothermal conditions. Temperature measurements are made by relating the intensity level of each pixel in a schlieren image to the corresponding knife-edge position measured at the exit focal plane of the schlieren system. The same schlieren images were also used to measure the velocity of the fluid flow by using optical flow techniques. The algorithm implemented analyzes motion between consecutive schlieren frames to obtain a tracked sequence and finally velocity fields. The proposed technique was applied to measure the temperature and velocity fields in natural convection of air due to unconfined and confined heated rectangular plates.

  17. Simultaneous measurements of air-sea gas transfer velocity and near surface turbulence at low to moderate winds (Invited)

    NASA Astrophysics Data System (ADS)

    Wang, B.; Liao, Q.; Fillingham, J. H.; Bootsma, H. A.

    2013-12-01

    Parameterization of air-sea gas transfer velocity was routinely made with wind speed. Near surface turbulent dissipation rate has been shown to have better correlation with the gas transfer velocity in a variety of aquatic environments (i.e., the small eddy model) while wind speed is low to moderate. Wind speed model may underestimate gas transfer velocity at low to moderate winds when the near surface turbulence is produced by other environmental forcing. We performed a series of field experiments to measure the CO2 transfer velocity, and the statistics of turbulence immediately below the air-water interface using a novel floating PIV and chamber system. The small eddy model was evaluated and the model coefficient was found to be a non-constant, and it varies with the local turbulent level (figure 1). Measure results also suggested an appropriate scaling of the vertical dissipation profile immediately below the interface under non-breaking conditions, which can be parameterized by the wind shear, wave height and wave age (figure 2). Figure 1. Relation between the coefficient of the small eddy model and dissipation rate. The data also include Chu & Jirka (2003) and Vachon et al. (2010). The solid regression line: α = 0.188log(ɛ)+1.158 Figure 2. Non-dimensional dissipation profiles. Symbols: measured data with the floating PIV. Solid line: regression of measured data with a -0.79 decaying rate. Dash line with -2 slope: Terray et al. (1996) relation. Dash line with two layer structure: Siddiqui & Loewen (2007) relation.

  18. Velocity profile, water-surface slope, and bed-material size for selected streams in Colorado

    USGS Publications Warehouse

    Marchand, J.P.; Jarrett, R.D.; Jones, L.L.

    1984-01-01

    Existing methods for determining the mean velocity in a vertical sampling section do not address the conditions present in high-gradient, shallow-depth streams common to mountainous regions such as Colorado. The report presents velocity-profile data that were collected for 11 streamflow-gaging stations in Colorado using both a standard Price type AA current meter and a prototype Price Model PAA current meter. Computational results are compiled that will enable mean velocities calculated from measurements by the two current meters to be compared with each other and with existing methods for determining mean velocity. Water-surface slope, bed-material size, and flow-characteristic data for the 11 sites studied also are presented. (USGS)

  19. Linearized stationary incompressible flow around rotating and translating bodies: Asymptotic profile of the velocity gradient and decay estimate of the second derivatives of the velocity

    NASA Astrophysics Data System (ADS)

    Deuring, Paul; Kračmar, Stanislav; Nečasová, Šárka

    We consider a system arising by linearization of a model for stationary viscous incompressible flow around a translating and rotating body. An asymptotic profile of the gradient of the velocity is derived. The leading term of the profile involves derivatives of a fundamental solution constructed by R.B. Guenther and E.A. Thomann (2006) [23], for the system in question. In addition, we establish decay estimates of the second derivatives of the velocity.

  20. Assessment of blood volume flow in slightly curved arteries from a single velocity profile.

    PubMed

    Leguy, C A D; Bosboom, E M H; Hoeks, A P G; van de Vosse, F N

    2009-08-07

    Non-invasive estimation of arterial blood volume flow (BVF) has become a central issue in assessment of cardiovascular risk. Poiseuille and Womersley approaches are commonly used to assess the BVF from centerline velocity, but both methods neglect the influence of curvature. Based on the assumption that the velocity in curved tubes as function of the circumferential position for a given radial position can be approximated by a cosine, the BVF can also be estimated by averaging velocities at opposite radial positions, referred to as the cosine theta model (CTM). This study investigates the accuracy of BVF estimation in slightly curved arteries for BVF waveforms obtained in the brachial artery of 6 volunteers. Computational fluid dynamics simulations were used to compute the influence of curvature on velocity profiles. The BVF was then estimated from the simulation results with the CTM and methods based on Poiseuille, Womersley and using the center stream velocity and the velocity waveform at the position where the maximum velocity is observed, and compared to the prescribed BVF. The simulations show that the influence of curvature is strongest when the flow decelerates. For Poiseuille and Womersley, the time average BVF was underestimated by maximally 10.4% and 7.8% for a radius of curvature of 50 and 100 mm, respectively. The estimation error is lower for the CTM and equals 4.2% and 1.2% for a radius of curvature of 50 and 100mm, respectively. From this study, we can conclude that the velocity waveform at the position of the maximum rather than the center stream velocity waveform combined with the Womersley method should be chosen. The CTM improves current estimation techniques if in-vivo velocity distributions are available.

  1. Laminar Flame Velocity and Temperature Exponent of Diluted DME-Air Mixture

    NASA Astrophysics Data System (ADS)

    Naseer Mohammed, Abdul; Anwar, Muzammil; Juhany, Khalid A.; Mohammad, Akram

    2017-03-01

    In this paper, the laminar flame velocity and temperature exponent diluted dimethyl ether (DME) air mixtures are reported. Laminar premixed mixture of DME-air with volumetric dilutions of carbon dioxides (CO2) and nitrogen (N2) are considered. Experiments were conducted using a preheated mesoscale high aspect-ratio diverging channel with inlet dimensions of 25 mm × 2 mm. In this method, flame velocities are extracted from planar flames that were stabilized near adiabatic conditions inside the channel. The flame velocities are then plotted against the ratio of mixture temperature and the initial reference temperature. A non-linear power law regression is observed suitable. This regression analysis gives the laminar flame velocity at the initial reference temperature and temperature exponent. Decrease in the laminar flame velocity and increase in temperature exponent is observed for CO2 and N2 diluted mixtures. The addition of CO2 has profound influence when compared to N2 addition on both flame velocity and temperature exponent. Numerical prediction of the similar mixture using a detailed reaction mechanism is obtained. The computational mechanism predicts higher magnitudes for laminar flame velocity and smaller magnitudes of temperature exponent compared to experimental data.

  2. Numerical Simulation of Transient Development of Flame, Temperature and Velocity under Reduced Gravity in a Methane Air Diffusion Flame

    NASA Astrophysics Data System (ADS)

    Bhowal, Arup Jyoti; Mandal, Bijan Kumar

    2017-02-01

    A methane air co flow diffusion flame has been numerically simulated with the help of an in-house developed code at normal gravity, 0.5 G, and 0.0001 G (microgravity) for the study of transient behavior of the flame in terms of flame shape, temperature profile and velocity (streamlines). The study indicates that lower is the gravity level, the higher is the time of early transience. The flame developments during transience are marked by the formation of a secondary flamelet at different heights above the primary flame at all gravity levels. The development of temperature profile at microgravity takes a much longer time to stabilize than the flame development. At normal gravity and 0.5 G gravity level, streamlines, during transience, show intermediate vortices which are finally replaced by recirculation of ambient air from the exit plane. At microgravity, neither any vortex nor any recirculation at any stage is observed. Centerline temperature plots, at all gravity levels during transience, demonstrate a secondary peak at some instants as a consequence of the secondary flamelet formation. The centerline velocity at microgravity decreases gradually during transience, unlike at other two gravity levels where the fall is very sharp and is indicative of negligible buoyancy at microgravity.

  3. Laser induced fluorescence measurements of axial velocity, velocity shear, and parallel ion temperature profiles during the route to plasma turbulence in a linear magnetized plasma device

    NASA Astrophysics Data System (ADS)

    Chakraborty Thakur, S.; Adriany, K.; Gosselin, J. J.; McKee, J.; Scime, E. E.; Sears, S. H.; Tynan, G. R.

    2016-11-01

    We report experimental measurements of the axial plasma flow and the parallel ion temperature in a magnetized linear plasma device. We used laser induced fluorescence to measure Doppler resolved ion velocity distribution functions in argon plasma to obtain spatially resolved axial velocities and parallel ion temperatures. We also show changes in the parallel velocity profiles during the transition from resistive drift wave dominated plasma to a state of weak turbulence driven by multiple plasma instabilities.

  4. Swash-zone velocity profiles and bed stress on a natural beach

    NASA Astrophysics Data System (ADS)

    Puleo, J. A.; Lanckriet, T.; Wang, P.

    2010-12-01

    The swash zone, where waves wash up and down the beach, is a difficult region of the nearshore to quantify velocity. Water depths in the swash zone can range from zero to over a meter and flows can be turbulent and bubble-laden. Swash flows are often assumed to be depth uniform partially because current meters typically cannot be placed closer than a few centimeters above the bed, although some previous field research has shown flow variability within elevations several centimeters above the bed. The swash-zone boundary layer, where flow momentum is transferred to the bed, must extend below elevations accessible to conventional current meters. Laser Doppler and video-based techniques have shown the shape of this boundary layer over smooth and rough impermeable and mobile granular beds in the laboratory, but to the author’s knowledge, the swash-zone boundary layer below 2-3 cm has never been measured on a natural beach. During August 16-19, 2010 a swash-zone study was conducted at several beaches in west-central Florida in an effort to measure the swash-zone boundary layer and bed shear stress. A new acoustic velocity profiling sensor, the Nortek Vectrino-II, has the capability to measure x, y and z velocity at 1mm increments over 30 bins at the finest setting. During the study 3 Vectrino-II’s were deployed with different profiling ranges in an effort to capture the boundary layer structure. Utilizing the velocity profile, bed stress is estimated using several different techniques including the “law of the wall” approach and nearbed velocity gradients. Preliminary results of the swash-zone boundary layer structure, friction velocity and bed stress as a function of swash phase will be discussed.

  5. 3-D Surface Depression Profiling Using High Frequency Focused Air-Coupled Ultrasonic Pulses

    NASA Technical Reports Server (NTRS)

    Roth, Don J.; Kautz, Harold E.; Abel, Phillip B.; Whalen, Mike F.; Hendricks, J. Lynne; Bodis, James R.

    1999-01-01

    Surface topography is an important variable in the performance of many industrial components and is normally measured with diamond-tip profilometry over a small area or using optical scattering methods for larger area measurement. This article shows quantitative surface topography profiles as obtained using only high-frequency focused air-coupled ultrasonic pulses. The profiles were obtained using a profiling system developed by NASA Glenn Research Center and Sonix, Inc (via a formal cooperative agreement). (The air transducers are available as off-the-shelf items from several companies.) The method is simple and reproducible because it relies mainly on knowledge and constancy of the sound velocity through the air. The air transducer is scanned across the surface and sends pulses to the sample surface where they are reflected back from the surface along the same path as the incident wave. Time-of-flight images of the sample surface are acquired and converted to depth/surface profile images using the simple relation (d = V*t/2) between distance (d), time-of-flight (t), and the velocity of sound in air (V). The system has the ability to resolve surface depression variations as small as 25 microns, is useable over a 1.4 mm vertical depth range, and can profile large areas only limited by the scan limits of the particular ultrasonic system. (Best-case depth resolution is 0.25 microns which may be achievable with improved isolation from vibration and air currents.) The method using an optimized configuration is reasonably rapid and has all quantitative analysis facilities on-line including 2-D and 3-D visualization capability, extreme value filtering (for faulty data), and leveling capability. Air-coupled surface profilometry is applicable to plate-like and curved samples. In this article, results are shown for several proof-of-concept samples, plastic samples burned in microgravity on the STS-54 space shuttle mission, and a partially-coated cylindrical ceramic

  6. Role of ionization and electron drift velocity profile to Rayleigh instability in a Hall thruster plasma

    SciTech Connect

    Singh, Sukhmander; Malik, Hitendra K.

    2012-07-01

    Role of ionization to Rayleigh instability is clarified in a Hall thruster plasma under the variety of profiles of electron drift velocity, namely, step-like profile (SLP) and two different super-Gaussian profiles (SGP1 and SGP2). For this, a relevant Rayleigh equation is derived and solved numerically using fourth-order Runge-Kutta method. Interestingly, an upper cutoff frequency of oscillations {omega}{sub max} is realized for the occurrence of the instability that shows dependence on the ionization rate {alpha}, electron drift velocity u{sub 0}, electron cyclotron frequency {Omega}, azimuthal wave number k{sub y}, plasma density n{sub 0}, density gradient {partial_derivative}n{sub 0}/{partial_derivative}x, ion (electron) thermal speed V{sub thI}(V{sub thE}), and ion (electron) plasma frequency {omega}{sub pi}({omega}{sub pe}). The frequency {omega}{sub max} follows the trend {omega}{sub max} (for SGP2) >{omega}{sub max} (for SLP) >{omega}{sub max} (for SGP1) and shows a similar behaviour with ionization for all types of the velocity profiles. The instability is found to grow faster for the higher {alpha} and the ion temperature but it acquires lower rate under the effect of the higher electron temperature; the perturbed potential also varies in accordance with the growth rate. The electron temperature influences the growth rate and cutoff frequency less significantly in comparison with the ion temperature.

  7. Variation in Velocity Profile with Change in Surface Roughness of Boundary

    NASA Technical Reports Server (NTRS)

    Jacobs, W

    1940-01-01

    The present report deals with the variation of a turbulent velocity profile in flow from rough to smooth wall and vice versa. Expressions obtained for the shear-stress distribution with respect to the distance from the point of junction of the different roughnesses and from the wall distance, are utilized to ascertain the developing velocity distributions. Under simplified assumptions, the use of these formulas renders possible the integration of the motion equations for the shear stress. This calculation is carried out and compared with the experiments.

  8. Three interfering beams in laser Doppler velocimetry for particle position and microflow velocity profile measurements.

    PubMed

    Onofri, Fabrice

    2006-05-10

    It is proposed to use three interfering and coplanar laser beams to form the probe volume of laser Doppler systems. This allows us to obtain, for each particle crossing this probe volume, a Doppler signal whose frequency amplitude spectrum exhibits two characteristic peaks. Electromagnetic calculations and experimental validations clearly demonstrate that we can estimate simultaneously, from the analysis of these two frequency peaks, the particle position along the optical axis and one velocity component. This technique is expected to have great potentialities for velocity profile measurements in microfluidic or boundary layer flows, as well as for the sizing of spherical particles.

  9. Convective cloud vertical velocity and mass-flux characteristics from radar wind profiler observations during GoAmazon2014/5: VERTICAL VELOCITY GOAMAZON2014/5

    SciTech Connect

    Giangrande, Scott E.; Toto, Tami; Jensen, Michael P.; Bartholomew, Mary Jane; Feng, Zhe; Protat, Alain; Williams, Christopher R.; Machado, Luiz

    2016-11-15

    A radar wind profiler data set collected during the 2 year Department of Energy Atmospheric Radiation Measurement Observations and Modeling of the Green Ocean Amazon (GoAmazon2014/5) campaign is used to estimate convective cloud vertical velocity, area fraction, and mass flux profiles. Vertical velocity observations are presented using cumulative frequency histograms and weighted mean profiles to provide insights in a manner suitable for global climate model scale comparisons (spatial domains from 20 km to 60 km). Convective profile sensitivity to changes in environmental conditions and seasonal regime controls is also considered. Aggregate and ensemble average vertical velocity, convective area fraction, and mass flux profiles, as well as magnitudes and relative profile behaviors, are found consistent with previous studies. Updrafts and downdrafts increase in magnitude with height to midlevels (6 to 10 km), with updraft area also increasing with height. Updraft mass flux profiles similarly increase with height, showing a peak in magnitude near 8 km. Downdrafts are observed to be most frequent below the freezing level, with downdraft area monotonically decreasing with height. Updraft and downdraft profile behaviors are further stratified according to environmental controls. These results indicate stronger vertical velocity profile behaviors under higher convective available potential energy and lower low-level moisture conditions. Sharp contrasts in convective area fraction and mass flux profiles are most pronounced when retrievals are segregated according to Amazonian wet and dry season conditions. During this deployment, wet season regimes favored higher domain mass flux profiles, attributed to more frequent convection that offsets weaker average convective cell vertical velocities.

  10. Preservation of Cognitive Performance with Age during Exertional Heat Stress under Low and High Air Velocity

    PubMed Central

    Wright Beatty, Heather E.; Keillor, Jocelyn M.; Hardcastle, Stephen G.; Boulay, Pierre; Kenny, Glen P.

    2015-01-01

    Older adults may be at greater risk for occupational injuries given their reduced capacity to dissipate heat, leading to greater thermal strain and potentially cognitive decrements. Purpose. To examine the effects of age and increased air velocity, during exercise in humid heat, on information processing and attention. Methods. Nine young (24 ± 1 years) and 9 older (59 ± 1 years) males cycled 4 × 15 min (separated by 15 min rest) at a fixed rate of heat production (400 W) in humid heat (35°C, 60% relative humidity) under 0.5 (low) and 3.0 (high) m·s−1 air velocity wearing coveralls. At rest, immediately following exercise (end exercise), and after the final recovery, participants performed an abbreviated paced auditory serial addition task (PASAT, 2 sec pace). Results. PASAT numbers of correct responses at end exercise were similar for young (low = 49 ± 3; high = 51 ± 3) and older (low = 46 ± 5; high = 47 ± 4) males and across air velocity conditions, and when scored relative to age norms. Psychological sweating, or an increased sweat rate with the administration of the PASAT, was observed in both age groups in the high condition. Conclusion. No significant decrements in attention and speeded information processing were observed, with age or altered air velocity, following intermittent exercise in humid heat. PMID:25874223

  11. Measurement of the Group Velocity Dispersion of air using a femtosecond comb

    NASA Astrophysics Data System (ADS)

    Al salamah, Reem

    In this thesis, the Group Velocity Dispersion (GVD) of air has been measured by using a femtosecond frequency comb at 1.5 microm. By comparing the spectra from a balanced and unbalanced Mach - Zehnder interferometer, the need for vacuum tube is eliminated. The method employs the Fast Fourier Transform of both auto- and cross correlation to find the spectral and their differences. The GVD of air is then calculated from these spectral phase differences. With twenty-five independent measurements, the GVD of air was found to be 0.0120 fs2/mm, with a standard deviation of 0.0075 fs2/mm.

  12. Extracting Short Rise-Time Velocity Profiles with Digital Down-Shift Analysis of Optically Up-Converted PDV Data

    SciTech Connect

    Abel Diaz, Nathan Riley, Cenobio Gallegos, Matthew Teel, Michael Berninger, Thomas W. Tunnell

    2010-09-08

    This work describes the digital down-shift (DDS) technique, a new method of extracting short rise-time velocity profiles in the analysis of optically up-converted PDV data. The DDS technique manipulates the PDV data by subtracting a constant velocity (i.e., the DDS velocity νDDS) from the velocity profile. DDS exploits the simple fact that the optically up-converted data ride on top of a base velocity (ν0, the apparent velocity at no motion) with a rapid rise to a high velocity (νf) of a few km/s or more. Consequently, the frequency content of the signal must describe a velocity profile that increases from ν0 to ν0 + νf. The DDS technique produces velocity reversals in the processed data before shock breakout when ν0 < νDDS < ν0 + νf. The DDS analysis process strategically selects specific DDS velocities (velocity at which the user down shifts the data) that produce anomalous reversals (maxima and/or minima), which are predictable and easy to identify in the mid-range of the data. Additional analysis determines when these maxima and minima occur. By successive application of the DDS technique and iterative analysis, velocity profiles are extracted as time as a function of velocity rather than as a function of time as it would be in a conventional velocity profile. Presented results include a description of DDS, velocity profiles extracted from laser-driven shock data with rise times of 200 ps or less, and a comparison with other techniques.

  13. Research on inert gas narcosis and air velocity effects on metabolic performance

    NASA Technical Reports Server (NTRS)

    1974-01-01

    The effects of air velocity on metabolic performance are studied by using high forced airflow in a closed environment as a mechanism to control the concentration of volatile animal wastes. Air velocities between 100 and 200 ft/min are without significant effects on the metabolism of rats. At velocities of 200 ft/min and above, oxygen consumption and CO2 production as well as food consumption increase. In most instances, the changes are on the order of 5-10%. At the same time, the RQ for the animals increases slightly and generally correlates well with oxygen consumption and CO2 production. Experiments on the nature of inert gas narcosis show that halothane and methoxyflurane are rather potent inhibitors of the NADH:O2 oxidoreductase system in rats. These experiments suggest that the mechanism of inert gas narcosis is not mandatorily related to a membrane surface phenomenon.

  14. A multi-channel, low velocity, hot film anemometry system for measuring air flows in buildings

    SciTech Connect

    Guire, J.L.

    1987-01-01

    A complete analytical and experimental development of a multichannel anemometry system is presented. The system consists of an array of low velocity sensors (0.0 m/s to 1.0 m/s), a constant current power supply, and the required data acquisition equipment. The velocity sensors can be scanned simultaneously yielding absolute air velocities and absolute ambient air temperatures at each of the probe positions in the array. One of the key results that this system can produce is the relationship between boundary layer flow and pressure driven flow through a large irregular aperture, such as a doorway, which up until now has been difficult to accomplish with regard to cost and experimental error incurred. 7 refs., 57 figs.

  15. Retrieval of Hydrometeor Drop Size Distributions from TRMM Field Campaign Profiler Doppler Velocity Spectra Observations

    NASA Technical Reports Server (NTRS)

    Williams, Christopher R.; Gage, Kenneth S.

    2003-01-01

    Consistent with the original proposal and work plan, this project focused on estimating the raindrop size distributions (DSDs) retrieved from vertically pointing Doppler radar profilers and analyzing the relationship of the retrieved DSDs with the dynamics of the precipitation processes. The first phase of this project focused on developing the model to retrieve the DSD from the observed Doppler velocity spectra. The second phase used this model to perform DSD retrievals from the profiler observations made during the TRMM Ground Validation Field Campaigns of TEFLUN-B, TRMM-LBA, and KWAJEX. The third phase of this project established collaborations with scientists involved with each field campaign in order to validate the profiler DSD estimates and to enable the profiler retrievals to be used in their research. Through these collaborations, the retrieved DSDs were placed into context with the dynamical processes of the observed precipitating cloud systems.

  16. THE SHAPES OF THE H I VELOCITY PROFILES OF THE THINGS GALAXIES

    SciTech Connect

    Ianjamasimanana, R.; De Blok, W. J. G.; Walter, Fabian; Heald, George H.

    2012-10-01

    We analyze the shapes of the H I velocity profiles of The H I Nearby Galaxy Survey to study the phase structure of the neutral interstellar medium and its relation to global galaxy properties. We use a method analogous to the stacking method sometimes used in high-redshift H I observations to construct high-signal-to-noise (S/N) profiles. We call these high-S/N profiles super profiles. We analyze and discuss possible systematics that may change the observed shapes of the super profiles. After quantifying these effects and selecting a subsample of unaffected galaxies, we find that the super profiles are best described by a narrow and a broad Gaussian component, which are evidence of the presence of the cold neutral medium and the warm neutral medium. The velocity dispersion of the narrow component ranges from {approx}3.4 to {approx}8.6 km s{sup -1} with an average of 6.5 {+-} 1.5 km s{sup -1}, whereas that of the broad component ranges from {approx}10.1 to {approx}24.3 km s{sup -1} with an average of 16.8 {+-} 4.3 km s{sup -1}. We find that the super profile parameters correlate with star formation indicators such as metallicity, far-UV-near-UV colors, and H{alpha} luminosities. The flux ratio between the narrow and broad components tends to be highest for high-metallicity, high-star-formation-rate galaxies. We show that the narrow component identified in the super profiles is associated with the presence of star formation, and possibly with molecular hydrogen.

  17. New sensor for measurement of low air flow velocity. Phase I final report

    SciTech Connect

    Hashemian, H.M.; Hashemian, M.; Riggsbee, E.T.

    1995-08-01

    The project described here is the Phase I feasibility study of a two-phase program to integrate existing technologies to provide a system for determining air flow velocity and direction in radiation work areas. Basically, a low air flow sensor referred to as a thermocouple flow sensor has been developed. The sensor uses a thermocouple as its sensing element. The response time of the thermocouple is measured using an existing in-situ method called the Loop Current Step Response (LCSR) test. The response time results are then converted to a flow signal using a response time-versus-flow correlation. The Phase I effort has shown that a strong correlation exists between the response time of small diameter thermocouples and the ambient flow rate. As such, it has been demonstrated that thermocouple flow sensors can be used successfully to measure low air flow rates that can not be measured with conventional flow sensors. While the thermocouple flow sensor developed in this project was very successful in determining air flow velocity, determining air flow direction was beyond the scope of the Phase I project. Nevertheless, work was performed during Phase I to determine how the new flow sensor can be used to determine the direction, as well as the velocity, of ambient air movements. Basically, it is necessary to use either multiple flow sensors or move a single sensor in the monitoring area and make flow measurements at various locations sweeping the area from top to bottom and from left to right. The results can then be used with empirical or physical models, or in terms of directional vectors to estimate air flow patterns. The measurements can be made continuously or periodically to update the flow patterns as they change when people and objects are moved in the monitoring area. The potential for using multiple thermocouple flow sensors for determining air flow patterns will be examined in Phase II.

  18. Spectral link for the mean velocity profile in the atmospheric boundary layer

    NASA Astrophysics Data System (ADS)

    Zhang, Dongrong; Gioia, Gustavo; Chakraborty, Pinaki

    2016-11-01

    Turbulent flow in the atmospheric boundary layer is sheared and stratified. For this flow, we consider the mean velocity profile (MVP), the vertical profile of the time-averaged horizontal wind velocity. We employ the theoretical framework of the spectral link, originally proposed for MVP in sheared flows (Gioia et al., 2010) and later extended to stratified flows (Katul et al., 2011). Accounting for the whole structure of the turbulent energy spectrum-the energetic range, the inertial range, and the dissipative range-we examine the scaling of the MVP in the "wall coordinates" and in the Monin-Obukhov similarity coordinates, for both stable and unstable stratification. Our results are in excellent accord with field measurements and numerical simulations. Okinawa Institute of Science and Technology.

  19. Three dimensional potential and current distributions in a Hall generator with assumed velocity profiles

    NASA Technical Reports Server (NTRS)

    Stankiewicz, N.; Palmer, R. W.

    1972-01-01

    Three-dimensional potential and current distributions in a Faraday segmented MHD generator operating in the Hall mode are computed. Constant conductivity and a Hall parameter of 1.0 is assumed. The electric fields and currents are assumed to be coperiodic with the electrode structure. The flow is assumed to be fully developed and a family of power-law velocity profiles, ranging from parabolic to turbulent, is used to show the effect of the fullness of the velocity profile. Calculation of the square of the current density shows that nonequilibrium heating is not likely to occur along the boundaries. This seems to discount the idea that the generator insulating walls are regions of high conductivity and are therefore responsible for boundary-layer shorting, unless the shorting is a surface phenomenon on the insulating material.

  20. Acoustic Doppler Current Profiler Surveys of Velocity Downstream of Albeni Falls Dam

    SciTech Connect

    Perkins, William A.; Titzler, P. Scott; Richmond, Marshall C.; Serkowski, John A.; Kallio, Sara E.; Bellgraph, Brian J.

    2010-09-30

    The U.S. Army Corps of Engineers (USACE), Seattle District, is studying the potential to locate fish bypass systems at Albeni Falls Dam. The USACE requested Pacific Northwest National Laboratory (PNNL) to survey velocity magnitude and direction in the dam tailrace. The empirical data collected will be used to support future numerical modeling, physical modeling, and evaluation of fish bypass system alternatives. In May 2010, PNNL conducted velocity surveys of the Albeni Falls Dam using a boat-mounted acoustic Doppler current profiler. The surveys were conducted over three days (May 25 through 27). During the survey period, total river discharge at the dam varied between 30.2 and 31.0 kcfs. A small amount of spill discharge, 2 kcfs, was present on two days (May 26 and 27). This report presents data plots showing measured velocity direction and magnitude averaged over the entire depth and over 5-ft depth increments from 5 to 30 ft.

  1. Profiling river surface velocities and volume flow estimation with bistatic UHF RiverSonde radar

    USGS Publications Warehouse

    Barrick, D.; Teague, C.; Lilleboe, P.; Cheng, R.; Gartner, J.; ,

    2003-01-01

    From the velocity profiles across the river, estimates of total volume flow for the four methods were calculated based on a knowledge of the bottom depth vs position across the river. It was found that the flow comparisons for the American River were much closer, within 2% of each other among all of the methods. Sources of positional biases and anomalies in the RiverSonde measurement patterns along the river were identified and discussed.

  2. Visualizing flow fields using acoustic Doppler current profilers and the Velocity Mapping Toolbox

    USGS Publications Warehouse

    Jackson, P. Ryan

    2013-01-01

    The purpose of this fact sheet is to provide examples of how the U.S. Geological Survey is using acoustic Doppler current profilers for much more than routine discharge measurements. These instruments are capable of mapping complex three-dimensional flow fields within rivers, lakes, and estuaries. Using the Velocity Mapping Toolbox to process the ADCP data allows detailed visualization of the data, providing valuable information for a range of studies and applications.

  3. Relationship between velocity profile and ultrasound echogenicity in pulsatile blood flows.

    PubMed

    Yeom, Eunseop; Lee, Sang Joon

    2015-01-01

    Pulsatile blood flows are easily found in the vessels of living organisms. Under pulsatile flow conditions, red blood cells (RBCs) are aggregated and dispersed repetitively. The phenomenon of RBC aggregation is an influential factor in hemorheological and hemodynamic properties. This study aims to investigate the relationship between velocity profile and RBC aggregation in pulsatile blood flows. A rat extracorporeal bypass model was adopted to generate a real pulsatile flow without changing the rheological properties. To check the stability of the experimental model, variations of the hemodynamic parameters were measured consecutively for 2 h. Ultrasound speckle images of the blood flow in the extracorporeal bypass loop were acquired using a 35-MHz ultrasound scanner. The velocity fields were measured by the speckle image velocimetry (SIV) method, in which the cross-correlation algorithm is applied to the speckle images. In addition, the RBC aggregation was estimated by analyzing the echogenicity distribution of the speckle images. The shape of the velocity profile was cyclically varied according to the cardiac cycle. This variation may be closely related to the variation of the echogenicity distribution in pulsatile flows. The simultaneous measurement of velocity and RBC aggregation would be useful for understanding the effects of the hemorheological features on the hemodynamic characteristics of pulsatile blood flows.

  4. Measurement of the near-wall velocity profile for a nanofluid flow inside a microchannel

    NASA Astrophysics Data System (ADS)

    Kanjirakat, Anoop; Sadr, Reza

    2015-11-01

    Hydrodynamics and anomalous heat transfer enhancements have been reported in the past for colloidal suspensions of nano-sized particles dispersed in a fluid (nanofluids). However, such augmentations may manifest itself by study of fluid flow characteristics near in the wall region. Present experimental study reports near-wall velocity profile for nanofluids (silicon dioxide nanoparticles in water) measured inside a microchannel. An objective-based nano-Particle Image Velocimetry (nPIV) technique is used to measure fluid velocity within three visible depths, O(100nm), from the wall. The near-wall fluid velocity profile is estimated after implementing the required corrections for optical properties and effects caused by hindered Brownian motion, wall-particle interactions, and non-uniform exponential illumination on the measurement technique. The fluid velocities of nanofluids at each of the three visible depths are observed to be higher than that of the base fluid resulting in a higher shear rate in this region. The relative increase in shear rates for nanofluids is believed to be the result of the near-wall shear-induced particle migration along with the Brownian motion of the nanoparticles. This research is funded by NPRP grant # 08-574-2-239 from the Qatar National Research Fund (a member of Qatar Foundation).

  5. Reconstructing the velocity dispersion profiles from the line-of-sight kinematic data in disc galaxies

    NASA Astrophysics Data System (ADS)

    Marchuk, A. A.; Sotnikova, N. Y.

    2017-03-01

    We present a modification of the method for reconstructing the stellar velocity ellipsoid (SVE) in disc galaxies. Our version does not need any parametrization of the velocity dispersion profiles and uses only one assumption that the ratio σz/σR remains constant along the profile or along several pieces of the profile. The method was tested on two galaxies from the sample of other authors and for the first time applied to three lenticular galaxies NGC 1167, NGC 3245 and NGC 4150, as well as to one Sab galaxy NGC 338. We found that for galaxies with a high inclination (i >55° - 60°) it is difficult or rather impossible to extract the information about SVE, while for galaxies at an intermediate inclination the procedure of extracting is successful. For NGC 1167 we managed to reconstruct SVE, provided that the value of σz/σR is piecewise constant. We found σz/σR = 0.7 for the inner parts of the disc and σz/σR = 0.3 for the outskirts. We also obtained a rigid constraint on the value of the radial velocity dispersion σR for highly inclined galaxies, and tested the result using the asymmetric-drift equation, provided that the gas rotation curve is available.

  6. Sensory and chemical characterization of VOC emissions from building products: impact of concentration and air velocity

    NASA Astrophysics Data System (ADS)

    Knudsen, H. N.; Kjaer, U. D.; Nielsen, P. A.; Wolkoff, P.

    The emissions from five commonly used building products were studied in small-scale test chambers over a period of 50 days. The odor intensity was assessed by a sensory panel and the concentrations of selected volatile organic compounds (VOCs) of concern for the indoor air quality were measured. The building products were three floor coverings: PVC, floor varnish on beechwood parquet and nylon carpet on a latex foam backing; an acrylic sealant, and a waterborne wall paint on gypsum board. The impacts of the VOC concentration in the air and the air velocity over the building products on the odor intensity and on the emission rate of VOCs were studied. The emission from each building product was studied under two or three different area-specific ventilation rates, i.e. different ratios of ventilation rate of the test chamber and building product area in the test chamber. The air velocity over the building product samples was adjusted to different levels between 0.1 and 0.3 m s -1. The origin of the emitted VOCs was assessed in order to distinguish between primary and secondary emissions. The results show that it is reasonable after an initial period of up to 14 days to consider the emission rate of VOCs of primary origin from most building products as being independent of the concentration and of the air velocity. However, if the building product surface is sensitive to oxidative degradation, increased air velocity may result in increased secondary emissions. The odor intensity of the emissions from the building products only decayed modestly over time. Consequently, it is recommended to use building products which have a low impact on the perceived air quality from the moment they are applied. The odor indices (i.e. concentration divided by odor threshold) of primary VOCs decayed markedly faster than the corresponding odor intensities. This indicates that the secondary emissions rather than the primary emissions, are likely to affect the perceived air quality in the

  7. Line-profile variations in radial-velocity measurements. Two alternative indicators for planetary searches

    NASA Astrophysics Data System (ADS)

    Figueira, P.; Santos, N. C.; Pepe, F.; Lovis, C.; Nardetto, N.

    2013-09-01

    Aims: We introduce two methods to identify false-positive planetary signals in the context of radial-velocity exoplanet searches. The first is the bi-Gaussian cross-correlation function fitting (and monitoring of the parameters derived from it), and the second is the measurement of asymmetry in radial-velocity spectral line information content, Vasy. We assess the usefulness of each of these methods by comparing their results with those delivered by current indicators. Methods: We make a systematic analysis of the most used common line profile diagnosis, Bisector Inverse Slope and Velocity Span, along with the two proposed ones. We evaluate all these diagnosis methods following a set of well-defined common criteria and using both simulated and real data. We apply them to simulated cross-correlation functions that are created with the program SOAP and which are affected by the presence of stellar spots. We consider different spot properties on stars with different rotation profiles and simulate observations as obtained with high-resolution spectrographs. We then apply our methodology to real cross-correlation functions, which are computed from HARPS spectra, for stars with a signal originating in activity (thus spots) and for those with a signal rooted on a planet. Results: We demonstrate that the bi-Gaussian method allows a more precise characterization of the deformation of line profiles than the standard bisector inverse slope. The calculation of the deformation indicator is simpler and its interpretation more straightforward. More importantly, its amplitude can be up to 30% larger than that of the bisector span, allowing the detection of smaller-amplitude correlations with radial-velocity variations. However, a particular parametrization of the bisector inverse slope is shown to be more efficient on high-signal-to-noise data than both the standard bisector and the bi-Gaussian. The results of the Vasy method show that this indicator is more effective than any of

  8. Crustal velocities near Coalinga, California, modeled from a combined earthquake/explosion refraction profile

    USGS Publications Warehouse

    Macgregor-Scott, N.; Walter, A.

    1988-01-01

    Crustal velocity structure for the region near Coalinga, California, has been derived from both earthquake and explosion seismic phase data recorded along a NW-SE seismic-refraction profile on the western flank of the Great Valley east of the Diablo Range. Comparison of the two data sets reveals P-wave phases in common which can be correlated with changes in the velocity structure below the earthquake hypocenters. In addition, the earthquake records reveal secondary phases at station ranges of less than 20 km that could be the result of S- to P-wave conversions at velocity interfaces above the earthquake hypocenters. Two-dimensional ray-trace modeling of the P-wave travel times resulted in a P-wave velocity model for the western flank of the Great Valley comprised of: 1) a 7- to 9-km thick section of sedimentary strata with velocities similar to those found elsewhere in the Great Valley (1.6 to 5.2 km s-1); 2) a middle crust extending to about 14 km depth with velocities comparable to those reported for the Franciscan assemblage in the Diablo Range (5.6 to 5.9 km s-1); and 3) a 13- to 14-km thick lower crust with velocities similar to those reported beneath the Diablo Range and the Great Valley (6.5 to 7.30 km s-1). This lower crust may have been derived from subducted oceanic crust that was thickened by accretionary underplating or crustal shortening. -Authors

  9. Laminar burning velocities and flame instabilities of butanol isomers-air mixtures

    SciTech Connect

    Gu, Xiaolei; Huang, Zuohua; Wu, Si; Li, Qianqian

    2010-12-15

    Laminar burning velocities and flame instabilities of the butanol-air premixed flames and its isomers are investigated using the spherically expanding flame with central ignition at initial temperature of 428 K and initial pressures of 0.10 MPa, 0.25 MPa, 0.50 MPa and 0.75 MPa. Laminar burning velocities and sensitivity factor of n-butanol-air mixtures are computed using a newly developed kinetic mechanism. Unstretched laminar burning velocity, adiabatic temperature, Lewis number, Markstein length, critical flame radius and Peclet number are obtained over a wide range of equivalence ratios. Effect of molecular structure on laminar burning velocity of the isomers of butanol is analyzed from the aspect of C-H bond dissociation energy. Study indicates that although adiabatic flame temperatures of the isomers of butanol are the same, laminar burning velocities give an obvious difference among the isomers of butanol. This indicates that molecular structure has a large influence on laminar burning velocities of the isomers of butanol. Branching (-CH3) will decrease laminar burning velocity. Hydroxyl functional group (-OH) attaching to the terminal carbon atoms gives higher laminar burning velocity compared to that attaching to the inner carbon atoms. Calculated dissociation bond energies show that terminal C-H bonds have larger bond energies than that of inner C-H bonds. n-Butanol, no branching and with hydroxyl functional group (-OH) attaching to the terminal carbon atom, gives the largest laminar burning velocity. tert-Butanol, with highly branching and hydroxyl functional group (-OH) attaching to the inner carbon atom, gives the lowest laminar burning velocity. Laminar burning velocities of iso-butanol and sec-butanol are between those of n-butanol and tert-butanol. The instant of transition to cellularity is experimentally determined for the isomers of butanol and subsequently interpreted on the basis of hydrodynamic and diffusion-thermal instabilities. Little effect

  10. Live performance of male broilers subjected to constant or increasing air velocities at moderate temperatures with a high dew point.

    PubMed

    Dozier, W A; Lott, B D; Branton, S L

    2005-08-01

    This study examined the effects of varying air velocities vs. a constant air velocity with a cyclic temperature curve of 25-30-25 degrees C and a dew point of 23 degrees C on broilers from 28 to 49 d of age. Four replicate trials were conducted. In each trial, 742 male broilers were randomly allocated to 6 floor pens or 2 air velocity tunnels, with each tunnel consisting of 4 pens. Bird density, feeder, and waterer space were similar across all pens (53 birds/ pen; 0.07 m2/bird). The treatments were control (still air), constant air velocity of 120 m/min, and increasing air velocity (90 m/min from 28 to 35 d, 120 m/min from 36 to 42 d, and 180 m/min from 43 to 49 d). Birds grown in a still air environment gained less weight, consumed less feed, and converted feed less efficiently between 28 and 49 d than birds subjected to moving air (constant or increasing). Growth responses between the air velocity treatments were similar from 28 to 35 and 36 to 42 d of age. Increasing air velocity to 180 m/min improved (P < or = 0.02) the growth rate of broilers from 43 to 49 d of age over birds receiving an air velocity of 120 m/min, but the incidence of mortality was not affected. These results provide evidence that increasing air velocity from 120 to 180 m/min is beneficial to broilers weighing 2.5 kg or greater when exposed to moderate temperatures.

  11. Optimization and investigation of the effect of velocity distribution of air curtains on the performance of food refrigerated display cabinets

    NASA Astrophysics Data System (ADS)

    Wu, XueHong; Chang, ZhiJuan; Ma, QiuYang; Lu, YanLi; Yin, XueMei

    2016-08-01

    This paper focuses on improving the performance of the vertical open refrigerated display cabinets (VORDC) by optimizing the structure of deflector, which is affected by inlet velocity and velocity distribution of air curtains. The results show that the temperature of products located at the front and at the rear reduces as the increases of inlet velocity of air curtains. The increase of the inlet velocity of air curtains can strengthen the disturbance inside the VORDC, and also decrease the temperature of products inside the VORDC; the increase of the outer velocity of air curtain will exacerbate the disturbance outside the VORDC and decrease air curtain's performance. The present study can provide a theoretical foundation for the design of VORDC.

  12. Experimental Studies of Low-Pressure Turbine Flows and Flow Control. Streamwise Pressure Profiles and Velocity Profiles

    NASA Technical Reports Server (NTRS)

    Volino, Ralph

    2012-01-01

    faculties. The geometry corresponded to "Pak B" LPT airfoil. The test section simulated LPT flow in a passage. Three experimental studies were performed: (a) Boundary layer measurements for ten baseline cases under high and low freestream turbulence conditions at five Reynolds numbers of 25,000, 50,000, 100,000, 200,000, and 300,000, based on passage exit velocity and suction surface wetted length; (b) Passive flow control studies with three thicknesses of two-dimensional bars, and two heights of three-dimensional circular cylinders with different spanwise separations, at same flow conditions as the 10 baseline cases; (c) Active flow control with oscillating synthetic (zero net mass flow) vortex generator jets, for one case with low freestream turbulence and a low Reynolds number of 25,000. The Passive flow control was successful at controlling the separation problem at low Reynolds numbers, with varying degrees of success from case to case and varying levels of impact at higher Reynolds numbers. The active flow control successfully eliminated the large separation problem for the low Reynolds number case. Very detailed data was acquired using hot-wire anemometry, including single and two velocity components, integral boundary layer quantities, turbulence statistics and spectra, turbulent shear stresses and their spectra, and intermittency, documenting transition, separation and reattachment. Models were constructed to correlate the results. The report includes a summary of the work performed and reprints of the publications describing the various studies. The folders in this supplement contain processed data in ASCII format. Streamwise pressure profiles and velocity profiles are included. The velocity profiles were acquired using single sensor and cross sensor hot-wire probes which were traversed from the wall to the freestream at various streamwise locations. In some of the flow control cases (3D Trips and Jets) profiles were acquired at multiple spanwise locations.

  13. Laser-Doppler velocity profile sensor with submicrometer spatial resolution that employs fiber optics and a diffractive lens.

    PubMed

    Büttner, Lars; Czarske, Jürgen; Knuppertz, Hans

    2005-04-20

    We report a novel laser-Doppler velocity profile sensor for microfluidic and nanofluidic applications and turbulence research. The sensors design is based on wavelength-division multiplexing. The high dispersion of a diffractive lens is used to generate a measurement volume with convergent and divergent interference fringes by means of two laser wavelengths. Evaluation of the scattered light from tracers allows velocity gradients to be measured in flows with submicrometer spatial resolution inside a measurement volume of 700-microm length. Using diffraction optics and fiber optics, we achieved a miniaturized and robust velocity profile sensor for highly resolved velocity measurements.

  14. A Method for Streamlining and Assessing Sound Velocity Profiles Based on Improved D-P Algorithm

    NASA Astrophysics Data System (ADS)

    Zhao, D.; WU, Z. Y.; Zhou, J.

    2015-12-01

    A multi-beam system transmits sound waves and receives the round-trip time of their reflection or scattering, and thus it is possible to determine the depth and coordinates of the detected targets using the sound velocity profile (SVP) based on Snell's Law. The SVP is determined by a device. Because of the high sampling rate of the modern device, the operational time of ray tracing and beam footprint reduction will increase, lowering the overall efficiency. To promote the timeliness of multi-beam surveys and data processing, redundant points in the original SVP must be screened out and at the same time, errors following the streamlining of the SVP must be evaluated and controlled. We presents a new streamlining and evaluation method based on the Maximum Offset of sound Velocity (MOV) algorithm. Based on measured SVP data, this method selects sound velocity data points by calculating the maximum distance to the sound-velocity-dimension based on an improved Douglas-Peucker Algorithm to streamline the SVP (Fig. 1). To evaluate whether the streamlined SVP meets the desired accuracy requirements, this method is divided into two parts: SVP streamlining, and an accuracy analysis of the multi-beam sounding data processing using the streamlined SVP. Therefore, the method is divided into two modules: the streamlining module and the evaluation module (Fig. 2). The streamlining module is used for streamlining the SVP. Its core is the MOV algorithm.To assess the accuracy of the streamlined SVP, we uses ray tracing and the percentage error analysis method to evaluate the accuracy of the sounding data both before and after streamlining the SVP (Fig. 3). By automatically optimizing the threshold, the reduction rate of sound velocity profile data can reach over 90% and the standard deviation percentage error of sounding data can be controlled to within 0.1% (Fig. 4). The optimized sound velocity profile data improved the operational efficiency of the multi-beam survey and data post

  15. Radial and Azimuthal Velocity Profiles in Gas-Puff Z-Pinches

    NASA Astrophysics Data System (ADS)

    Rocco, Sophia; Engelbrecht, Joseph; Banasek, Jacob; de Grouchy, Philip; Qi, Niansheng; Hammer, David

    2016-10-01

    The dynamics of neon, argon, and krypton (either singly or in combination) gas puff z-pinch plasmas are studied on Cornell's 1MA, 100-200ns rise-time COBRA pulsed power generator. The triple-nozzle gas puff valve, consisting of two annular gas puffs and a central jet, allows radial tailoring of the gas puff mass-density profile and the use of 1, 2 or 3 different gases at different pressures. Interferometry supplies information on sheath thickness and electron density, variously filtered PCDs and silicon diodes measure hard and soft x-ray production, and multi frame visible and extreme UV imaging systems allow tracking of the morphology of the plasma. A 527nm, 10J Thomson scattering diagnostic system is used to determine radial and azimuthal velocities. Implosion velocities of 170km/s (Kr) and 300km/s (Ne/Ar) are observed. We are investigating the correlations between instability growth, plasma density profile, velocity partitioning as a function of radius, and radiation production. Research supported by the NNSA Stewardship Sciences Academic Programs under DOE Cooperative Agreement No. DE-NA0001836.

  16. A Hypothetical Burning-Velocity Formula for Very Lean Hydrogen-Air Mixtures

    SciTech Connect

    Williams, Forman; Williams, Forman A; Grcar, Joseph F

    2008-06-30

    Very lean hydrogen-air mixtures experience strong diffusive-thermal types of cellular instabilities that tend to increase the laminar burning velocity above the value that applies to steady, planar laminar flames that are homogeneous in transverse directions. Flame balls constitute an extreme limit of evolution of cellular flames. To account qualitatively for the ultimate effect of diffusive-thermal instability, a model is proposed in which the flame is a steadily propagating, planar, hexagonal, close-packed array of flame balls, each burning as if it were an isolated, stationary, ideal flame ball in an infinite, quiescent atmosphere. An expression for the laminar burning velocity is derived from this model, which theoretically may provide an upper limit for the experimental burning velocity.

  17. Measurements of Flat-Flame Velocities of Diethyl Ether in Air

    PubMed Central

    Gillespie, Fiona; Metcalfe, Wayne K.; Dirrenberger, Patricia; Herbinet, Olivier; Glaude, Pierre-Alexandre; Battin-Leclerc, Frédérique; Curran, Henry J.

    2013-01-01

    This study presents new adiabatic laminar burning velocities of diethyl ether in air, measured on a flat-flame burner using the heat flux method. The experimental pressure was 1 atm and temperatures of the fresh gas mixture ranged from 298 to 398 K. Flame velocities were recorded at equivalence ratios from 0.55 to 1.60, for which stabilization of the flame was possible. The maximum laminar burning velocity was found at an equivalence ratio of 1.10 or 1.15 at different temperatures. These results are compared with experimental and computational data reported in the literature. The data reported in this study deviate significantly from previous experimental results and are well-predicted by a previously reported chemical kinetic mechanism. PMID:23710107

  18. River habitat quality from river velocities measured using acoustic Doppler current profiler.

    PubMed

    Shields, F Douglas; Rigby, J R

    2005-10-01

    Prior research has demonstrated the utility of metrics based on spatial velocity gradients to characterize and describe stream habitat, with higher gradients generally indicative of higher levels of physical heterogeneity and thus habitat quality. However, detailed velocity data needed to compute these metrics are difficult to obtain. Acoustic Doppler current profilers (ADCP) may be used to rapidly collect detailed representations of river velocity fields. Herein we demonstrate use of ADCP to obtain ecologically relevant data and compute associated metrics. Data were collected from four reaches of the Little Tallahatchie River in northern Mississippi. Sampled reaches were selected to observe velocity regimes associated with three distinctly different conditions: downstream from a major flow obstruction (a low weir), downstream from the apices of each of two bends, and within an extremely long, straight reach created by channelization. Three-dimensional velocity data sets from each site were used to compute metrics of habitat quality proposed by others. A habitat metric based on the presence of rotational flow in the vertical plane proved to be the best discriminator among conditions within the sampled reaches. Two of four habitat quality metrics computed from these measured velocities were greatest for the sharpest meander bend. ADCP hold great potential for study of riverine physical aquatic habitats, particularly at the reach scale. Additional work is needed to develop generally applicable field protocols and data reduction tools. Specifically, guidelines for ADCP settings and configuration appropriate for a range of riverine site conditions must be developed. Advances in instrumentation are needed to allow collection of information in closer proximity to the free surface and solid boundaries.

  19. A comparison of vertical velocity variance measurements from wind profiling radars and sonic anemometers

    NASA Astrophysics Data System (ADS)

    McCaffrey, Katherine; Bianco, Laura; Johnston, Paul; Wilczak, James M.

    2017-03-01

    Observations of turbulence in the planetary boundary layer are critical for developing and evaluating boundary layer parameterizations in mesoscale numerical weather prediction models. These observations, however, are expensive and rarely profile the entire boundary layer. Using optimized configurations for 449 and 915 MHz wind profiling radars during the eXperimental Planetary boundary layer Instrumentation Assessment (XPIA), improvements have been made to the historical methods of measuring vertical velocity variance through the time series of vertical velocity, as well as the Doppler spectral width. Using six heights of sonic anemometers mounted on a 300 m tower, correlations of up to R2 = 0. 74 are seen in measurements of the large-scale variances from the radar time series and R2 = 0. 79 in measurements of small-scale variance from radar spectral widths. The total variance, measured as the sum of the small and large scales, agrees well with sonic anemometers, with R2 = 0. 79. Correlation is higher in daytime convective boundary layers than nighttime stable conditions when turbulence levels are smaller. With the good agreement with the in situ measurements, highly resolved profiles up to 2 km can be accurately observed from the 449 MHz radar and 1 km from the 915 MHz radar. This optimized configuration will provide unique observations for the verification and improvement to boundary layer parameterizations in mesoscale models.

  20. The influence of the tangential velocity of inner rotating wall on axial velocity profile of flow through vertical annular pipe with rotating inner surface

    NASA Astrophysics Data System (ADS)

    Sharf, Abdusalam M.; Jawan, Hosen A.; Almabsout, Fthi A.

    2014-03-01

    In the oil and gas industries, understanding the behaviour of a flow through an annulus gap in a vertical position, whose outer wall is stationary whilst the inner wall rotates, is a significantly important issue in drilling wells. The main emphasis is placed on experimental (using an available rig) and computational (employing CFD software) investigations into the effects of the rotation speed of the inner pipe on the axial velocity profiles. The measured axial velocity profiles, in the cases of low axial flow, show that the axial velocity is influenced by the rotation speed of the inner pipe in the region of almost 33% of the annulus near the inner pipe, and influenced inversely in the rest of the annulus. The position of the maximum axial velocity is shifted from the centre to be nearer the inner pipe, by increasing the rotation speed. However, in the case of higher flow, as the rotation speed increases, the axial velocity is reduced and the position of the maximum axial velocity is skewed towards the centre of the annulus. There is a reduction of the swirl velocity corresponding to the rise of the volumetric flow rate.

  1. Measurements of laminar burning velocities for natural gas-hydrogen-air mixtures

    SciTech Connect

    Huang, Zuohua; Zhang, Yong; Zeng, Ke; Liu, Bing; Wang, Qian; Jiang, Deming

    2006-07-15

    Laminar flame characteristics of natural gas-hydrogen-air flames were studied in a constant-volume bomb at normal temperature and pressure. Laminar burning velocities and Markstein lengths were obtained at various ratios of hydrogen to natural gas (volume fraction from 0 to 100%) and equivalence ratios (f from 0.6 to 1.4). The influence of stretch rate on flame was also analyzed. The results show that, for lean mixture combustion, the flame radius increases with time but the increasing rate decreases with flame expansion for natural gas and for mixtures with low hydrogen fractions, while at high hydrogen fractions, there exists a linear correlation between flame radius and time. For rich mixture combustion, the flame radius shows a slowly increasing rate at early stages of flame propagation and a quickly increasing rate at late stages of flame propagation for natural gas and for mixtures with low hydrogen fractions, and there also exists a linear correlation between flame radius and time for mixtures with high hydrogen fractions. Combustion at stoichiometric mixture demonstrates the linear relationship between flame radius and time for natural gas-air, hydrogen-air, and natural gas-hydrogen-air flames. Laminar burning velocities increase exponentially with the increase of hydrogen fraction in mixtures, while the Markstein length decreases and flame instability increases with the increase of hydrogen fractions in mixture. For a fixed hydrogen fraction, the Markstein number shows an increase and flame stability increases with the increase of equivalence ratios. Based on the experimental data, a formula for calculating the laminar burning velocities of natural gas-hydrogen-air flames is proposed. (author)

  2. Effects of inflow velocity profile on two-dimensional hemodynamic analysis by ordinary and ultrasonic-measurement-integrated simulations.

    PubMed

    Kato, Takaumi; Sone, Shusaku; Funamoto, Kenichi; Hayase, Toshiyuki; Kadowaki, Hiroko; Taniguchi, Nobuyuki

    2016-09-01

    Two-dimensional ultrasonic-measurement-integrated (2D-UMI) simulation correctly reproduces hemodynamics even with an inexact inflow velocity distribution. This study aimed to investigate which is superior, a two-dimensional ordinary (2D-O) simulation with an accurate inflow velocity distribution or a 2D-UMI simulation with an inaccurate one. 2D-O and 2D-UMI simulations were performed for blood flow in a carotid artery with four upstream velocity boundary conditions: a velocity profile with backprojected measured Doppler velocities (condition A), and velocity profiles with a measured Doppler velocity distribution, a parabolic one, and a uniform one, magnitude being obtained by inflow velocity estimation (conditions B, C, and D, respectively). The error of Doppler velocity against the measurement data was sensitive to the inflow velocity distribution in the 2D-O simulation, but not in the 2D-UMI simulation with the inflow velocity estimation. Among the results in conditions B, C, and D, the error in the worst 2D-UMI simulation with condition D was 31 % of that in the best 2D-O simulation with condition B, implying the superiority of the 2D-UMI simulation with an inaccurate inflow velocity distribution over the 2D-O simulation with an exact one. Condition A resulted in a larger error than the other conditions in both the 2D-O and 2D-UMI simulations.

  3. Quantifying energy and mass transfer in crop canopies: sensors for measurement of temperature and air velocity.

    PubMed

    Bugbee, B; Monje, O; Tanner, B

    1996-01-01

    Here we report on the in situ performance of inexpensive, miniature sensors that have increased our ability to measure mass and energy fluxes from plant canopies in controlled environments: 1. Surface temperature. Canopy temperature measurements indicate changes in stomatal aperture and thus latent and sensible heat fluxes. Infrared transducers from two manufacturers (Exergen Corporation, Newton, MA; and Everest Interscience, Tucson, AZ, USA) have recently become available. Transducer accuracy matched that of a more expensive hand-held infrared thermometer. 2. Air velocity varies above and within plant canopies and is an important component in mass and energy transfer models. We tested commercially-available needle, heat-transfer anemometers (1 x 50 mm cylinder) that consist of a fine-wire thermocouple and a heater inside a hypodermic needle. The needle is heated and wind speed determined from the temperature rise above ambient. These sensors are particularly useful in measuring the low wind speeds found within plant canopies. 3. Accurate measurements of air temperature adjacent to plant leaves facilitates transport phenomena modeling. We quantified the effect of radiation and air velocity on temperature rise in thermocouples from 10 to 500 micrometers. At high radiation loads and low wind speeds, temperature errors were as large as 7 degrees C above air temperature.

  4. Quantifying energy and mass transfer in crop canopies: sensors for measurement of temperature and air velocity

    NASA Technical Reports Server (NTRS)

    Bugbee, B.; Monje, O.; Tanner, B.

    1996-01-01

    Here we report on the in situ performance of inexpensive, miniature sensors that have increased our ability to measure mass and energy fluxes from plant canopies in controlled environments: 1. Surface temperature. Canopy temperature measurements indicate changes in stomatal aperture and thus latent and sensible heat fluxes. Infrared transducers from two manufacturers (Exergen Corporation, Newton, MA; and Everest Interscience, Tucson, AZ, USA) have recently become available. Transducer accuracy matched that of a more expensive hand-held infrared thermometer. 2. Air velocity varies above and within plant canopies and is an important component in mass and energy transfer models. We tested commercially-available needle, heat-transfer anemometers (1 x 50 mm cylinder) that consist of a fine-wire thermocouple and a heater inside a hypodermic needle. The needle is heated and wind speed determined from the temperature rise above ambient. These sensors are particularly useful in measuring the low wind speeds found within plant canopies. 3. Accurate measurements of air temperature adjacent to plant leaves facilitates transport phenomena modeling. We quantified the effect of radiation and air velocity on temperature rise in thermocouples from 10 to 500 micrometers. At high radiation loads and low wind speeds, temperature errors were as large as 7 degrees C above air temperature.

  5. Tuning a physically-based model of the air-sea gas transfer velocity

    NASA Astrophysics Data System (ADS)

    Jeffery, C. D.; Robinson, I. S.; Woolf, D. K.

    Air-sea gas transfer velocities are estimated for one year using a 1-D upper-ocean model (GOTM) and a modified version of the NOAA-COARE transfer velocity parameterization. Tuning parameters are evaluated with the aim of bringing the physically based NOAA-COARE parameterization in line with current estimates, based on simple wind-speed dependent models derived from bomb-radiocarbon inventories and deliberate tracer release experiments. We suggest that A = 1.3 and B = 1.0, for the sub-layer scaling parameter and the bubble mediated exchange, respectively, are consistent with the global average CO 2 transfer velocity k. Using these parameters and a simple 2nd order polynomial approximation, with respect to wind speed, we estimate a global annual average k for CO 2 of 16.4 ± 5.6 cm h -1 when using global mean winds of 6.89 m s -1 from the NCEP/NCAR Reanalysis 1 1954-2000. The tuned model can be used to predict the transfer velocity of any gas, with appropriate treatment of the dependence on molecular properties including the strong solubility dependence of bubble-mediated transfer. For example, an initial estimate of the global average transfer velocity of DMS (a relatively soluble gas) is only 11.9 cm h -1 whilst for less soluble methane the estimate is 18.0 cm h -1.

  6. Investigations of the air flow velocity field structure above the wavy surface under severe wind conditions by particle image velosimetry technique.

    NASA Astrophysics Data System (ADS)

    Troitskaya, Yuliya; Kandaurov, Alexander; Sergeev, Daniil; Ermakova, Olga

    2013-04-01

    Preliminary experiments devoted to measuring characteristics of the air flow above the waved water surface for the wide range of wind speeds were performed with the application of modified Particle Image Velosimetry (PIV) technique. Experiments were carried out at the Wind - wave stratified flume of IAP RAS (length 10 °, cross section of air channel 0.4×0.4 m) for four different axial wind speeds: 8.7, 13.5, 19 and 24 m/s, corresponding to the equivalent 10-m wind speeds 15, 20, 30 40 m/s correspondingly. Intensive wave breaking with forming foam crest and droplets generations was occurred for two last wind conditions. The modified PIV-method based on the use of continuous-wave (CW) laser illumination of the airflow seeded by tiny particles and with highspeed video. Spherical 20 μm polyamide particles with density 1.02 g/sm3 and inertial time 7•10-3 s were used for seeding airflow with special injecting device. Green (532 nm) CW laser with 4 Wt output power was used as a source for light sheet. High speed digital camera Videosprint was used for taking visualized air flow images with the frame rate 2000 Hz s and exposure time 10 ms Combination including iteration Canny method [1] for obtaining curvilinear surface from the images in the laser sheet view and contact measurements of surface elevation by wire wave gauge installed near the border of working area for the surface wave profile was used. Then velocity air flow field was retrieved by PIV images processing with adaptive cross-correlation method on the curvilinear grid following surface wave profile. The mean wind velocity profiles were retrieved by averaging over obtained ensembles of wind velocity field realizations and over a wave period even for the cases of intensive wave breaking and droplets generation. To verify the PIV method additional measurements of mean velocity profiles over were carried out by the contact method using the Pitot tube. In the area of overlap, wind velocity profiles measured by

  7. Three-dimensional visualization of velocity profiles in the ascending aorta in dogs, measured with a hot-film anemometer.

    PubMed

    Paulsen, P K; Hasenkam, J M

    1983-01-01

    Three-dimensional blood velocity profiles were registered in the ascending aorta of dogs approximately 2 and 5 cm above the aortic valves by means of constant temperature hot-film anemometry. The velocity was measured at 41 predetermined points of measurement evenly distributed over the cross-sectional area. Later data analyses using a three-dimensional plotting system, visualized velocity profiles at 200 time intervals during one mean heart cycle. The overall appearance of the profiles was that of a flat transitional flow with a slight skewness. The highest velocity was found nearer to the posterior and left vessel wall. The skewness started during top systole and persisted to the beginning of diastole. Furthermore, many small velocity fluctuations were seen during top systole, but they might also be caused by secondary rotational flow phenomena. This new three-dimensional and dynamic method for visualizing velocity profiles seems to offer advantages, as it demonstrates the total velocity profile all over the cross-sectional area.

  8. Effects of light intensity light quality and air velocity on temperature in plant reproductive organs

    NASA Astrophysics Data System (ADS)

    Kitaya, Y.; Hirai, H.

    Excess temperature increase in plant reproductive organs such as anthers and stigmata could cause fertility impediments and thus produce sterile seeds under artificial lighting conditions in closed plant growth facilities There is a possibility that the aberration was caused by an excess increase in temperatures of reproductive organs in Bioregenerative Life Support Systems under microgravity conditions in space The fundamental study was conducted to know the thermal situation of the plant reproductive organs as affected by light intensity light quality and air velocity on the earth and to estimate the excess temperature increase in the reproductive organs in closed plant growth facilities in space Thermal images of reproductive organs of rice and strawberry were captured using infrared thermography at an air temperature of 10 r C The temperatures in flowers at 300 mu mol m -2 s -1 PPFD under the lights from red LEDs white LEDs blue LEDs fluorescent lamps and incandescent lamps increased by 1 4 1 7 1 9 6 0 and 25 3 r C respectively for rice and by 2 8 3 4 4 1 7 8 and 43 4 r C respectively for strawberry The flower temperatures increased with increasing PPFD levels The temperatures in petals anthers and stigmas of strawberry at 300 mu mol m -2 s -1 PPFD under incandescent lamps increased by 32 7 29 0 and 26 6 r C respectively at 0 1 m s -1 air velocity and by 20 6 18 5 and 15 9 r C respectively at 0 8 m s -1 air velocity The temperatures of reproductive organs decreased with increasing

  9. Noninvasive measurement of steady and pulsating velocity profiles and shear rates in arteries using echo PIV: in vitro validation studies.

    PubMed

    Kim, Hyoung-Bum; Hertzberg, Jean; Lanning, Craig; Shandas, Robin

    2004-08-01

    Although accurate measurement of velocity profiles, multiple velocity vectors, and shear stress in arteries is important, there is still no easy method to obtain such information in vivo. We report on the utility of combining ultrasound contrast imaging with particle image velocimetry (PIV) for noninvasive measurement of velocity vectors. This method (echo PIV) takes advantage of the strong backscatter characteristics of small gas-filled microbubbles (contrast) seeded into the flow. The method was tested in vitro. The steady flow analytical solution and optical PIV measurements (for pulsatile flow) were used for comparison. When compared to the analytical solution, both echo PIV and optical PIV resolved the steady velocity profile well. Error in shear rate as measured by echo PIV (8%) was comparable to the error of optical PIV (6.5%). In pulsatile flow, echo PIV velocity profiles agreed well with optical PIV profiles. Echo PIV followed the general profile of pulsatile shear stress across the artery but underestimated wall shear at certain time points. However, error in shear from echo PIV was an order of magnitude less than error from current shear measurement methods. These studies indicate that echo PIV is a promising technique for noninvasive measurement of velocity profiles and shear stress.

  10. Trapezoidal Wing Experimental Repeatability and Velocity Profiles in the 14- by 22-Foot Subsonic Tunnel

    NASA Technical Reports Server (NTRS)

    Hannon, Judith A.; Washburn, Anthony E.; Jenkins, Luther N.; Watson, Ralph D.

    2012-01-01

    The AIAA Applied Aerodynamics Technical Committee sponsored a High Lift Prediction Workshop held in June 2010. For this first workshop, data from the Trapezoidal Wing experiments were used for comparison to CFD. This paper presents long-term and short-term force and moment repeatability analyses for the Trapezoidal Wing model tested in the NASA Langley 14- by 22-Foot Subsonic Tunnel. This configuration was chosen for its simplified high-lift geometry, publicly available set of test data, and previous CFD experience with this configuration. The Trapezoidal Wing is a three-element semi-span swept wing attached to a body pod. These analyses focus on configuration 1 tested in 1998 (Test 478), 2002 (Test 506), and 2003 (Test 513). This paper also presents model velocity profiles obtained on the main element and on the flap during the 1998 test. These velocity profiles are primarily at an angle of attack of 28 degrees and semi-span station of 83% and show confluent boundary layers and wakes.

  11. The effect of humidity on ionic wind velocity in ambient air

    NASA Astrophysics Data System (ADS)

    Chen, She; Nobelen, J. C. P. Y.; Nijdam, S.

    2016-09-01

    Due to the evolution of portable electronics and LED lightning system, advances in air cooling technologies must also keep pace. Active cooling by ionic wind, which is usually generated by corona discharge, can greatly reduce the noise and lifetime issues compared to the mechanical fans. The wind is induced when a gas discharge is formed, and neutral molecules gain their energy by the momentum transfer of ion-neutral collisions. However, there is few discussion about the effect of gas composition such as humidity on the wind generation and the physical mechanism is not clear. In the experiment, a positive 5-20 kV DC voltage is applied to the needle-cylinder electrodes with separation of 20 mm. The ionic wind velocity is measured by hot wire anemometry. As the relative humidity (RH) in the ambient air increases, the velocity is found to be severely inhibited. The current is also measured between the cylinder electrode and earth. The results show that the DC component of corona current decreases when RH increases. Since both the discharge current and the ion mobility are reduced when RH increases, their combined effects determine the ionic wind velocity. This work is supported by STW project 13651.

  12. Design of container velocity profile for the suppression of liquid sloshing

    NASA Astrophysics Data System (ADS)

    Kim, Dongjoo

    2016-11-01

    In many industrial applications, high-speed position control of a liquid container causes undesirable liquid vibrations called 'sloshing' which poses a control challenge in fast maneuvering and accurate positioning of containers. Recently, it has been shown that a control theory called 'input shaping' is successfully applied to reduce the sloshing, but its success comes at a cost of longer process time. Therefore, we aim to minimize liquid sloshing without increasing the process time when a container moves horizontally by a target distance within a limited time. In this study, sensing and feedback actuation are not permitted but the container velocity is allowed to be modified from a given triangular profile. A new design is proposed by applying input shaping to the container velocity with carefully selected acceleration time. That is, the acceleration time is chosen to be the 1st mode natural period, and the input shaper is determined based on the 3rd mode natural frequency. The proposed approach is validated by performing numerical simulations, which show that the simple modification of container velocity reduces the sloshing significantly without additional process time in a feedforward manner. Supported by the NRF programs (NRF-2015R1D1A1A01059675) of Korean government.

  13. Wave Structure and Velocity Profiles in Downwards Gas-Liquid Annular Flows

    NASA Astrophysics Data System (ADS)

    Zadrazil, Ivan; Hewitt, Geoff; Matar, Omar; Markides, Christos

    2012-11-01

    A downwards flow of gas in the core of a vertical pipe, and of liquid in the annulus between the pipe wall and the gas phase is referred to as a ``downwards annular flow'' (DAF). DAFs are conventionally described in terms of short-lived, small-amplitude ``ripples,'' and large-amplitude, high-speed ``disturbances.'' We use a combination of Laser Induced Fluorescence (LIF), Particle Image and Tracking Velocimetry (PIV, PTV) to study DAFs. We demonstrate through these techniques that the liquid films become progressively more complex with increasing liquid Reynolds number (ReL), while a similar increase of complexity is observed for increasing gas Reynolds number (ReG). Disturbance waves are observed for low and high ReL, and ripples for intermediate ReL. Additionally, a high degree of rolling breakdown of disturbance waves is observed in falling films at the highest ReL, which is a source of bubble entrainment into the film body. Our results will comprise: (i) statistical data on film thickness, and (ii) wave frequency, velocity, wavelength. In addition, a qualitative (e.g. re-circulation zones) and quantitative (e.g. mean/rms velocity profiles) velocity characterisation of the film flows will be presented.

  14. An Idea of Staged and Large Velocity Differential Secondary Air for Waterwall Erosion Protection and Oxygen Complementarity

    NASA Astrophysics Data System (ADS)

    Liu, B. Q.; Zhang, X. H.

    A successful design of circulating fluidized bed (CFB) boiler should have the highest combustion efficiency, economic operation, and optimum availability. There is a coupled phenomenon of an oxygen lean zone existing in the CFB boiler furnace which depresses combustion efficiency and particle (group) falling down faster and faster when it falls along the waterwall, abrading the tube metal effectively. A new secondary air design for the oxygen lean zone and erosion protection is conceived by using staged and large velocity differential secondary air. For example, a part of concentrate supplied secondary air has been divided into two parts: a low velocity part and a high velocity part. The low velocity part is used for rigid gas layer to reduce the particle falling velocity, and the high velocity part is used for oxygen supply. It is believed that 40˜6Om/s projecting air velocity could send new oxygen to at least half furnace depth in a short projecting lift as shown in calculation. In another view point, operational superficial gas velocity has an obvious effect on waterwall metal erosion, with a lower operation velocity having lower erosion.

  15. Burning Velocity Measurements in Aluminum-Air Suspensions using Bunsen Type Dust Flames

    NASA Technical Reports Server (NTRS)

    Lee, John; Goroshin, Samuel; Kolbe, Massimiliano

    2001-01-01

    Laminar burning velocity (sometimes also referred in literature as fundamental or normal flame propagation speed) is probably the most important combustion characteristic of the premixed combustible mixture. The majority of experimental data on burning velocities in gaseous mixtures was obtained with the help of the Bunsen conical flame. The Bunsen cone method was found to be sufficiently accurate for gaseous mixtures with burning velocities higher than 10-15 cm/s at normal pressure. Hans Cassel was the first to demonstrate that suspensions of micron-size solid fuel particles in a gaseous oxidizer can also form self-sustained Bunsen flames. He was able to stabilize Bunsen flames in a number of suspensions of different nonvolatile solid fuels (aluminum, carbon, and boron). Using the Bunsen cone method he estimated burning velocities in the premixed aluminum-air mixtures (particle size less than 10 microns) to be in the range of 30-40 cm/s. Cassel also found, that the burning velocity in dust clouds is a function of the burner diameter. In our recent work, we have used the Bunsen cone method to investigate dependence of burning velocity on dust concentration in fuel-rich aluminum dust clouds. Burning velocities in stoichiometric and fuel-rich aluminum dust suspensions with average particle sizes of about 5 microns were found to be in the range of 20-25 cm/s and largely independent on dust concentration. These results raise the question to what degree burning velocities derived from Bunsen flame specifically and other dust flame configurations in general, are indeed fundamental characteristics of the mixture and to what degree are they apparatus dependent. Dust flames in comparison to gas combustion, are thicker, may be influenced by radiation heat transfer in the flame front, respond differently to heat losses, and are fundamentally influenced by the particular flow configuration due to the particles inertia. Since characteristic spatial scales of dust flames are

  16. Velocity and temperature field characteristics of water and air during natural convection heating in cans.

    PubMed

    Erdogdu, Ferruh; Tutar, Mustafa

    2011-01-01

    Presence of headspace during canning is required since an adequate amount allows forming vacuum during the process. Sealing technology may not totally eliminate all entrapped gases, and headspace might affect heat transfer. Not much attention has been given to solve this problem in computational studies, and cans, for example, were mostly assumed to be fully filled with product. Therefore, the objective of this study was to determine velocity and temperature evolution of water and air in cans during heating to evaluate the relevance of headspace in the transport mechanism. For this purpose, canned water samples with a certain headspace were used, and required governing continuity, energy, and momentum equations were solved using a finite volume approach coupled with a volume of fluid element model. Simulation results correlated well with experimental results validating faster heating effects of headspace rather than insulation effects as reported in the literature. The organized velocity motions along the air-water interface were also shown. Practical Application: Canning is a universal and economic method for processing of food products, and presence of adequate headspace is required to form vacuum during sealing of the cans. Since sealing technology may not totally eliminate the entrapped gases, mainly air, headspace might affect heating rates in cans. This study demonstrated the increased heating rates in the presence of headspace in contrast with some studies in the literature. By applying the effect of headspace, required processing time for thermally processed foods can be reduced leading to more rapid processes and lower energy consumptions.

  17. Comparison of index velocity measurements made with a horizontal acoustic Doppler current profiler

    USGS Publications Warehouse

    Jackson, P. Ryan; Johnson, Kevin K.; Duncker, James J.

    2012-01-01

    The State of Illinois' annual withdrawal from Lake Michigan is limited by a U.S. Supreme Court decree, and the U.S. Geological Survey (USGS) is responsible for monitoring flows in the Chicago Sanitary and Ship Canal (CSSC) near Lemont, Illinois as a part of the Lake Michigan Diversion Accounting overseen by the U.S. Army Corps of Engineers, Chicago District. Every 5 years, a technical review committee consisting of practicing engineers and academics is convened to review the U.S. Geological Survey's streamgage practices in the CSSC near Lemont, Illinois. The sixth technical review committee raised a number of questions concerning the flows and streamgage practices in the CSSC near Lemont and this report provides answers to many of those questions. In addition, it is the purpose of this report to examine the index velocity meters in use at Lemont and determine whether the acoustic velocity meter (AVM), which is now the primary index velocity meter, can be replaced by the horizontal acoustic Doppler current profiler (H-ADCP), which is currently the backup meter. Application of the AVM and H-ADCP to index velocity measurements in the CSSC near Lemont, Illinois, has produced good ratings to date. The site is well suited to index velocity measurements in spite of the large range of velocities and highly unsteady flows at the site. Flow variability arises from a range of sources: operation of the waterway through control structures, lockage-generated disturbances, commercial and recreational traffic, industrial withdrawals and discharges, natural inflows, seiches, and storm events. The influences of these factors on the index velocity measurements at Lemont is examined in detail in this report. Results of detailed data comparisons and flow analyses show that use of bank-mounted instrumentation such as the AVM and H-ADCP appears to be the best option for index velocity measurement in the CSSC near Lemont. Comparison of the rating curves for the AVM and H-ADCP demonstrates

  18. Temperature, velocity and Species Profile Measurements for Reburning in a Pulverized, Entrained Flow, Coal Combustor

    SciTech Connect

    Tree, D.R.

    1997-10-01

    Measurements of effluent NO{sub x}, CO, and O{sub 2} have been obtained for various reburning locations in the controlled profile reactor. the location of the reburning zone and tertiary air zone have been varied to find an optimal location for detailed reburning profile measurements. No{sub x} reduction of greater than 70% has been seen with natural gas injection in and just below the primary combustion zone. Strategic injection of the natural gas for reburning reduces the total No{sub x} reduction capability of reburning. Modeling efforts continue in trying to match the modeling solution to the detailed baseline data taken in previous measurement. The use of more accurate measured boundary conditions did not appear to improve the model predictions greatly but the use of more detailed turbulence models was found to improve the predictions, the predictions are still far from matching the combustion measurements.

  19. Acoustic and aerodynamic performance investigation of inverted velocity profile coannular plug nozzles. [variable cycle engines

    NASA Technical Reports Server (NTRS)

    Knott, P. R.; Blozy, J. T.; Staid, P. S.

    1981-01-01

    The results of model scale parametric static and wind tunnel aerodynamic performance tests on unsuppressed coannular plug nozzle configurations with inverted velocity profile are discussed. The nozzle configurations are high-radius-ratio coannular plug nozzles applicable to dual-stream exhaust systems typical of a variable cycle engine for Advanced Supersonic Transport application. In all, seven acoustic models and eight aerodynamic performance models were tested. The nozzle geometric variables included outer stream radius ratio, inner stream to outer stream ratio, and inner stream plug shape. When compared to a conical nozzle at the same specific thrust, the results of the static acoustic tests with the coannular nozzles showed noise reductions of up to 7 PNdB. Extensive data analysis showed that the overall acoustic results can be well correlated using the mixed stream velocity and the mixed stream density. Results also showed that suppression levels are geometry and flow regulation dependent with the outer stream radius ratio, inner stream-to-outer stream velocity ratio and inner stream velocity ratio and inner stream plug shape, as the primary suppression parameters. In addition, high-radius ratio coannular plug nozzles were found to yield shock associated noise level reductions relative to a conical nozzle. The wind tunnel aerodynamic tests showed that static and simulated flight thrust coefficient at typical takeoff conditions are quite good - up to 0.98 at static conditions and 0.974 at a takeoff Mach number of 0.36. At low inner stream flow conditions significant thrust loss was observed. Using an inner stream conical plug resulted in 1% to 2% higher performance levels than nozzle geometries using a bent inner plug.

  20. A model for sound velocity in a two-phase air-water bubbly flow

    SciTech Connect

    Chung, N.M.; Lin, W.K.; Pei, B.S.; Hsu, Y.Y. )

    1992-07-01

    In this paper, wave propagation in a homogeneous, low void fraction, two-phase air-water bubbly flow is analyzed through the compressibility of a single bubble to derive a P({rho}) relation; the dispersion relation is then derived by a homogeneous model. The phase velocity and attenuation calculated from the model are compared with existing data and are in good agreement. The momentum transfer effect is considered through the virtual mass term and is significant at a higher void fraction. The interfacial heat transfer between phases is significant at low frequency, while bubble scattering effects are important at high frequency (near resonance). Bubble behavior at both low and high frequency is derived based on the isothermal and the adiabatic cases, respectively. The phase velocity occurs at the limiting condition in both cases. Furthermore, resonance is present in the model, and the resonant frequency is determined.

  1. Molecular dynamic simulation of Ar-Kr mixture across a rough walled nanochannel: Velocity and temperature profiles

    SciTech Connect

    Pooja, Ahluwalia, P. K.; Pathania, Y.

    2015-05-15

    This paper presents the results from a molecular dynamics simulation of mixture of argon and krypton in the Poiseuille flow across a rough walled nanochannel. The roughness effect on liquid nanoflows has recently drawn attention The computational software used for carrying out the molecular dynamics simulations is LAMMPS. The fluid flow takes place between two parallel plates and is bounded by horizontal rough walls in one direction and periodic boundary conditions are imposed in the other two directions. Each fluid atom interacts with other fluid atoms and wall atoms through Leenard-Jones (LJ) potential with a cut off distance of 5.0. To derive the flow a constant force is applied whose value is varied from 0.1 to 0.3 and velocity profiles and temperature profiles are noted for these values of forces. The velocity profile and temperature profiles are also looked at different channel widths of nanochannel and at different densities of mixture. The velocity profile and temperature profile of rough walled nanochannel are compared with that of smooth walled nanochannel and it is concluded that mean velocity increases with increase in channel width, force applied and decrease in density also with introduction of roughness in the walls of nanochannel mean velocity again increases and results also agree with the analytical solution of a Poiseuille flow.

  2. Temperature, velocity and species profile measurements for reburning in a pulverized, entrained flow, coal combustor

    SciTech Connect

    Tree, D.R.

    1999-03-01

    Nitrogen oxide emissions from pulverized coal combustion have been and will continue to be a regulated pollutant for electric utility boilers burning pulverized coal. Full scale combustion models can help in the design of new boilers and boiler retrofits which meet emissions standards, but these models require validation before they can be used with confidence. The objective of this work was to obtain detailed combustion measurements of pulverized coal flames which implement two NO reduction strategies, namely reburning and advanced reburning, to provide data for model validation. The data were also compared to an existing comprehensive pulverized coal combustion model with a reduced mechanism for NO reduction under reburning and advanced reburning conditions. The data were obtained in a 0.2 MW, cylindrical, down-fired, variable swirl, pulverized coal reactor. The reactor had a diameter of 0.76 m and a length of 2.4 m with access ports along the axial length. A Wyodak, sub-bituminous coal was used in all of the measurements. The burner had a centrally located primary fuel and air tube surrounded by heated and variably swirled secondary air. Species of NO, NO{sub x}, CO, CO{sub 2} and O{sub 2} were measured continuously. Aqueous sampling was used to measure HCN and NH{sub 3} at specific reactor locations. Samples were drawn from the reactor using water quenched suction probes. Velocity measurements were obtained using two component laser doppler anemometry in back-scatter mode. Temperature measurements were obtained using a shielded suction pyrometer. A series of six or more radial measurements at six or more axial locations within the reactor provided a map of species, temperature, and velocity measurements. In total, seven reactor maps were obtained. Three maps were obtained at baseline conditions of 0, 0.5 and 1.5 swirl and 10% excess air. Two maps were obtained under reburning conditions of 0.78 stoichiometric ratio and 1.5 swirl and 0.9 stoichiometric ratio and

  3. Effect of low air velocities on thermal homeostasis and comfort during exercise at space station operational temperature and humidity

    NASA Technical Reports Server (NTRS)

    Beumer, Ronald J.

    1989-01-01

    The effectiveness of different low air velocities in maintaining thermal comfort and homeostasis during exercise at space station operational temperature and humidity was investigated. Five male subjects exercised on a treadmill for successive ten minute periods at 60, 71, and 83 percent of maximum oxygen consumption at each of four air velocities, 30, 50, 80, and 120 ft/min, at 22 C and 62 percent relative humidity. No consistent trends or statistically significant differences between air velocities were found in body weight loss, sweat accumulation, or changes in rectal, skin, and body temperatures. Occurrence of the smallest body weight loss at 120 ft/min, the largest sweat accumulation at 30 ft/min, and the smallest rise in rectal temperature and the greatest drop in skin temperature at 120 ft/min all suggested more efficient evaporative cooling at the highest velocity. Heat storage at all velocities was evidenced by increased rectal and body temperatures; skin temperatures declined or increased only slightly. Body and rectal temperature increases corresponded with increased perception of warmth and slight thermal discomfort as exercise progressed. At all air velocities, mean thermal perception never exceeded warm and mean discomfort, greatest at 30 ft/min, was categorized at worst as uncomfortable; sensation of thermal neutrality and comfort returned rapidly after cessation of exercise. Suggestions for further elucidation of the effects of low air velocities on thermal comfort and homeostasis include larger numbers of subjects, more extensive skin temperature measurements and more rigorous analysis of the data from this study.

  4. Dynamics of Air Temperature, Velocity and Ammonia Emissions in Enclosed and Conventional Pig Housing Systems

    PubMed Central

    Song, J. I.; Park, K.-H.; Jeon, J. H.; Choi, H. L.; Barroga, A. J.

    2013-01-01

    This study aimed to compare the dynamics of air temperature and velocity under two different ventilation and housing systems during summer and winter in Korea. The NH3 concentration of both housing systems was also investigated in relation to the pig’s growth. The ventilation systems used were; negative pressure type for the enclosed pig house (EPH) and natural airflow for the conventional pig house (CPH). Against a highly fluctuating outdoor temperature, the EPH was able to maintain a stable temperature at 24.8 to 29.1°C during summer and 17.9 to 23.1°C during winter whilst the CPH had a wider temperature variance during summer at 24.7 to 32.3°C. However, the temperature fluctuation of the CPH during winter was almost the same with that of EPH at 14.5 to 18.2°C. The NH3 levels in the CPH ranged from 9.31 to 16.9 mg/L during summer and 5.1 to 19.7 mg/L during winter whilst that of the EPH pig house was 7.9 to 16.1 mg/L and 3.7 to 9.6 mg/L during summer and winter, respectively. These values were less than the critical ammonia level for pigs with the EPH maintaining a lower level than the CPH in both winter and summer. The air velocity at pig nose level in the EPH during summer was 0.23 m/s, enough to provide comfort because of the unique design of the inlet feature. However, no air movement was observed in almost all the lower portions of the CPH during winter because of the absence of an inlet feature. There was a significant improvement in weight gain and feed intake of pigs reared in the EPH compared to the CPH (p<0.05). These findings proved that despite the difference in the housing systems, a stable indoor temperature was necessary to minimize the impact of an avoidable and highly fluctuating outdoor temperature. The EPH consistently maintained an effective indoor airspeed irrespective of season; however the CPH had defective and stagnant air at pig nose level during winter. Characteristics of airflow direction and pattern were consistent relative to

  5. Comparison of phase velocities from array measurements of Rayleigh waves associated with microtremor and results calculated from borehole shear-wave velocity profiles

    USGS Publications Warehouse

    Liu, Hsi-Ping; Boore, David M.; Joyner, William B.; Oppenheimer, David H.; Warrick, Richard E.; Zhang, Wenbo; Hamilton, John C.; Brown, Leo T.

    2000-01-01

    Shear-wave velocities (VS) are widely used for earthquake ground-motion site characterization. VS data are now largely obtained using borehole methods. Drilling holes, however, is expensive. Nonintrusive surface methods are inexpensive for obtaining VS information, but not many comparisons with direct borehole measurements have been published. Because different assumptions are used in data interpretation of each surface method and public safety is involved in site characterization for engineering structures, it is important to validate the surface methods by additional comparisons with borehole measurements. We compare results obtained from a particular surface method (array measurement of surface waves associated with microtremor) with results obtained from borehole methods. Using a 10-element nested-triangular array of 100-m aperture, we measured surface-wave phase velocities at two California sites, Garner Valley near Hemet and Hollister Municipal Airport. The Garner Valley site is located at an ancient lake bed where water-saturated sediment overlies decomposed granite on top of granite bedrock. Our array was deployed at a location where seismic velocities had been determined to a depth of 500 m by borehole methods. At Hollister, where the near-surface sediment consists of clay, sand, and gravel, we determined phase velocities using an array located close to a 60-m deep borehole where downhole velocity logs already exist. Because we want to assess the measurements uncomplicated by uncertainties introduced by the inversion process, we compare our phase-velocity results with the borehole VS depth profile by calculating fundamental-mode Rayleigh-wave phase velocities from an earth model constructed from the borehole data. For wavelengths less than ~2 times of the array aperture at Garner Valley, phase-velocity results from array measurements agree with the calculated Rayleigh-wave velocities to better than 11%. Measurement errors become larger for wavelengths 2

  6. Numerical performance analysis of acoustic Doppler velocity profilers in the wake of an axial-flow marine hydrokinetic turbine

    SciTech Connect

    Richmond, Marshall C.; Harding, Samuel F.; Romero Gomez, Pedro DJ

    2015-09-01

    The use of acoustic Doppler current profilers (ADCPs) for the characterization of flow conditions in the vicinity of both experimental and full scale marine hydrokinetic (MHK) turbines is becoming increasingly prevalent. The computation of a three dimensional velocity measurement from divergent acoustic beams requires the assumption that the flow conditions are homogeneous between all beams at a particular axial distance from the instrument. In the near wake of MHK devices, the mean fluid motion is observed to be highly spatially dependent as a result of torque generation and energy extraction. This paper examines the performance of ADCP measurements in such scenarios through the modelling of a virtual ADCP (VADCP) instrument in the velocity field in the wake of an MHK turbine resolved using unsteady computational fluid dynamics (CFD). This is achieved by sampling the CFD velocity field at equivalent locations to the sample bins of an ADCP and performing the coordinate transformation from beam coordinates to instrument coordinates and finally to global coordinates. The error in the mean velocity calculated by the VADCP relative to the reference velocity along the instrument axis is calculated for a range of instrument locations and orientations. The stream-wise velocity deficit and tangential swirl velocity caused by the rotor rotation lead to significant misrepresentation of the true flow velocity profiles by the VADCP, with the most significant errors in the transverse (cross-flow) velocity direction.

  7. Anomalous Velocity Dependence of the Friction Coefficient of an Air Supported Pulley

    NASA Astrophysics Data System (ADS)

    Crismani, Matteo; Nauenberg, Michael

    2009-11-01

    A standard undergraduate lab exercise to verify Newton's law, F = ma, is to measure the acceleration a of a glider of mass m suspended on an air track. In our experiment the glider is accelerated by a thin tape attached to the glider at one end, and to a weight of mass M at the other end. The weight hangs vertically via a pulley over which the tape is suspended by air pressure. In the absence of friction, the force pulling the glider is F = (M m/(M + m)g, where g is the acceleration of gravity. To the accuracy provided by the fast electronic timers (accurate to 1/10000 second) used in our experiment to measure the velocity and the acceleration of the glider, we verified that the friction due to the air track can be neglected. But we found that this is not the case for the friction due to the air pulley which adds a component -v/T to the force F on the glider, where T is the friction coefficient. We have measured the dependence of this coefficient on v, and found an excellent analytic fit to our data. This fit deviates considerable from the conventional assumption that 1/T is a constant and/or depends linearly on v.

  8. Effectiveness of an Individualized Training Based on Force-Velocity Profiling during Jumping

    PubMed Central

    Jiménez-Reyes, Pedro; Samozino, Pierre; Brughelli, Matt; Morin, Jean-Benoît

    2017-01-01

    Ballistic performances are determined by both the maximal lower limb power output (Pmax) and their individual force-velocity (F-v) mechanical profile, especially the F-v imbalance (FVimb): difference between the athlete's actual and optimal profile. An optimized training should aim to increase Pmax and/or reduce FVimb. The aim of this study was to test whether an individualized training program based on the individual F-v profile would decrease subjects' individual FVimb and in turn improve vertical jump performance. FVimb was used as the reference to assign participants to different training intervention groups. Eighty four subjects were assigned to three groups: an “optimized” group divided into velocity-deficit, force-deficit, and well-balanced sub-groups based on subjects' FVimb, a “non-optimized” group for which the training program was not specifically based on FVimb and a control group. All subjects underwent a 9-week specific resistance training program. The programs were designed to reduce FVimb for the optimized groups (with specific programs for sub-groups based on individual FVimb values), while the non-optimized group followed a classical program exactly similar for all subjects. All subjects in the three optimized training sub-groups (velocity-deficit, force-deficit, and well-balanced) increased their jumping performance (12.7 ± 5.7% ES = 0.93 ± 0.09, 14.2 ± 7.3% ES = 1.00 ± 0.17, and 7.2 ± 4.5% ES = 0.70 ± 0.36, respectively) with jump height improvement for all subjects, whereas the results were much more variable and unclear in the non-optimized group. This greater change in jump height was associated with a markedly reduced FVimb for both force-deficit (57.9 ± 34.7% decrease in FVimb) and velocity-deficit (20.1 ± 4.3%) subjects, and unclear or small changes in Pmax (−0.40 ± 8.4% and +10.5 ± 5.2%, respectively). An individualized training program specifically based on FVimb (gap between the actual and optimal F-v profiles of

  9. Shear banding in a lyotropic lamellar phase. I. Time-averaged velocity profiles

    NASA Astrophysics Data System (ADS)

    Salmon, Jean-Baptiste; Manneville, Sébastien; Colin, Annie

    2003-11-01

    Using velocity profile measurements based on dynamic light scattering and coupled to structural and rheological measurements in a Couette cell, we present evidences for a shear banding scenario in the shear flow of the onion texture of a lyotropic lamellar phase. Time-averaged measurements clearly show the presence of structural shear banding in the vicinity of a shear-induced transition, associated with the nucleation and growth of a highly sheared band in the flow. Our experiments also reveal the presence of slip at the walls of the Couette cell. Using a simple mechanical approach, we demonstrate that our data confirm the classical assumption of the shear banding picture, in which the interface between bands lies at a given stress σ*. We also outline the presence of large temporal fluctuations of the flow field, which are the subject of the second part of this paper [Salmon et al., Phys. Rev. E 68, 051504 (2003)].

  10. Evolution of density and velocity profiles of matter in large voids

    NASA Astrophysics Data System (ADS)

    Tsizh, M.; Novosyadlyj, B.

    2016-09-01

    We analyse the evolution of cosmological perturbations which leads to the formation of large voids in the distribution of galaxies. We assume that perturbations are spherical and all components of the Universe - radiation, matter and dark energy - are continuous media with ideal fluid energy-momentum tensors, which interact only gravitationally. Equations of the evolution of perturbations in the comoving to cosmological background reference frame for every component are obtained from equations of conservation and Einstein's ones and are integrated by modified Euler method. Initial conditions are set at the early stage of evolution in the radiation-dominated epoch, when the scale of perturbation is mush larger than the particle horizon. Results show how the profiles of density and velocity of matter in spherical voids with different overdensity shells are formed.

  11. Velocity profiles between two baffles in a shell and tube heat exchanger

    NASA Astrophysics Data System (ADS)

    Chang, Tae-Hyun; Lee, Chang-Hoan; Lee, Hae-Soo; Lee, Kwon-Soo

    2015-06-01

    Heat exchangers are extensively utilized for waste heat recovery, oil refining, chemical processing, and steam generation. In this study, velocity profiles are measured using a 3D particle image velocimetry (PIV) system betweentwo baffles in a shell and tube heat exchanger for parallel and counter flows. The PIV and computational fluid dynamics results show the occurrence of some strong vectors near the bottom. These vectors are assumed due to the clearance between the inner tubes and the front baffle. Therefore, the major parts of the vectors are moved out through the bottom opening of the rear baffle, and other vectors produce a large circle between the two baffles. Numerical simulations are conducted to investigate the effects of the baffle on the heat exchanger using the Fluent software. The k-ɛ turbulence model is employed to calculate the flows along the heat exchanger

  12. A beam-scan type laser Doppler velocimeter for simultaneous and continuous measurement of velocity profiles

    NASA Astrophysics Data System (ADS)

    Hino, M.; Nadaoka, K.; Kobayashi, T.; Sato, Y.; Muramoto, T.

    A beam-scan-type LDV (SLV) with high spatial resolving power has been developed for the continuous measurement of nearly simultaneous velocity profiles in the cross sections of various flows. The SLV consists of a forward-scatter LDV and a beam-scan unit, using a reversed-scan method, capable of high-speed scanning of the measuring volume. An autofocusing device using an image sensor is employed to simplify the alignment of the receiving optics needed to match the transmitting optics. The SLV performance was validated by comparison of experimental results (for a wake flow of a circular cylinder, a reciprocally oscillatory flow, and a Karman vortex street flow) with flow visualization and computational results.

  13. Feasible domain of Walker's unsteady wall-layer model for the velocity profile in turbulent flows.

    PubMed

    Mikhailov, Mikhail D; Freire, Atila P Silva

    2014-12-01

    The present work studies, in detail, the unsteady wall-layer model of Walker et al. (1989, AIAA J., 27, 140 – 149) for the velocity profile in turbulent flows. Two new terms are included in the transcendental nonlinear system of equations that is used to determine the three main model parameters. The mathematical and physical feasible domains of the model are determined as a function of the non-dimensional pressure gradient parameter (p+). An explicit parameterization is presented for the average period between bursts (T+B), the origin of time (t+0 ) and the integration constant of the time dependent equation (A0) in terms of p+. In the present procedure, all working systems of differential equations are transformed, resulting in a very fast computational procedure that can be used to develop real-time flow simulators.

  14. Vertical velocity variance in the mixed layer from radar wind profilers

    USGS Publications Warehouse

    Eng, K.; Coulter, R.L.; Brutsaert, W.

    2003-01-01

    Vertical velocity variance data were derived from remotely sensed mixed layer turbulence measurements at the Atmospheric Boundary Layer Experiments (ABLE) facility in Butler County, Kansas. These measurements and associated data were provided by a collection of instruments that included two 915 MHz wind profilers, two radio acoustic sounding systems, and two eddy correlation devices. The data from these devices were available through the Atmospheric Boundary Layer Experiment (ABLE) database operated by Argonne National Laboratory. A signal processing procedure outlined by Angevine et al. was adapted and further built upon to derive vertical velocity variance, w_pm???2, from 915 MHz wind profiler measurements in the mixed layer. The proposed procedure consisted of the application of a height-dependent signal-to-noise ratio (SNR) filter, removal of outliers plus and minus two standard deviations about the mean on the spectral width squared, and removal of the effects of beam broadening and vertical shearing of horizontal winds. The scatter associated with w_pm???2 was mainly affected by the choice of SNR filter cutoff values. Several different sets of cutoff values were considered, and the optimal one was selected which reduced the overall scatter on w_pm???2 and yet retained a sufficient number of data points to average. A similarity relationship of w_pm???2 versus height was established for the mixed layer on the basis of the available data. A strong link between the SNR and growth/decay phases of turbulence was identified. Thus, the mid to late afternoon hours, when strong surface heating occurred, were observed to produce the highest quality signals.

  15. Velocity measurements within a shock and reshock induced air/SF6 turbulent mixing zone

    NASA Astrophysics Data System (ADS)

    Haas, Jean-Francois; Bouzgarrou, Ghazi; Bury, Yannick; Jamme, Stephane; Joly, Laurent; Shock-induced mixing Team

    2012-11-01

    A turbulent mixing zone (TMZ) is created in a shock tube (based in ISAE, DAEP) when a Mach 1.2 shock wave in air accelerates impulsively to 70 m/s an air/SF6 interface. The gases are initially separated by a 1 μm thick plastic microfilm maintained flat and parallel to the shock by two wire grids. The upper grid of square spacing 1.8 mm imposes the nonlinear initial perturbation for the Richtmyer-Meshkov instability (RMI). After interaction with a reshock and a rarefaction, the TMZ remains approximately stagnant but much more turbulent. High speed Schlieren visualizations enable the choice of abscissae for Laser Doppler Velocity (LDV) measurements. For a length of the SF6 section equal to 250 mm, the LDV abscissae are 43, 135 and 150 mm from the initial position of the interface. Because of numerous microfilm fragments in the flow and a limited number of olive oil droplets as seeding particles for the LDV, statistical convergence requires the superposition of a least 50 identical runs at each abscissa. The dependence of TMZ structure and velocity field on length of the SF6 section between 100 and 300 mm will be presented. This experimental investigation is carried out in support of modeling and multidimensional simulation efforts at CEA, DAM, DIF. Financial support from CEA is thanksfully appreciated by ISAE.

  16. Effect of airstream velocity on mean drop diameters of water sprays produced by pressure and air atomizing nozzles

    NASA Technical Reports Server (NTRS)

    Ingebo, R. D.

    1977-01-01

    A scanning radiometer was used to determine the effect of airstream velocity on the mean drop diameter of water sprays produced by pressure atomizing and air atomizing fuel nozzles used in previous combustion studies. Increasing airstream velocity from 23 to 53.4 meters per second reduced the Sauter mean diameter by approximately 50 percent with both types of fuel nozzles. The use of a sonic cup attached to the tip of an air assist nozzle reduced the Sauter mean diameter by approximately 40 percent. Test conditions included airstream velocities of 23 to 53.4 meters per second at 293 K and atmospheric pressure.

  17. Shear-wave velocity profiling according to three alternative approaches: A comparative case study

    NASA Astrophysics Data System (ADS)

    Dal Moro, G.; Keller, L.; Al-Arifi, N. S.; Moustafa, S. S. R.

    2016-11-01

    The paper intends to compare three different methodologies which can be used to analyze surface-wave propagation, thus eventually obtaining the vertical shear-wave velocity (VS) profile. The three presented methods (currently still quite unconventional) are characterized by different field procedures and data processing. The first methodology is a sort of evolution of the classical Multi-channel Analysis of Surface Waves (MASW) here accomplished by jointly considering Rayleigh and Love waves (analyzed according to the Full Velocity Spectrum approach) and the Horizontal-to-Vertical Spectral Ratio (HVSR). The second method is based on the joint analysis of the HVSR curve together with the Rayleigh-wave dispersion determined via Miniature Array Analysis of Microtremors (MAAM), a passive methodology that relies on a small number (4 to 6) of vertical geophones deployed along a small circle (for the common near-surface application the radius usually ranges from 0.6 to 5 m). Finally, the third considered approach is based on the active data acquired by a single 3-component geophone and relies on the joint inversion of the group-velocity spectra of the radial and vertical components of the Rayleigh waves, together with the Radial-to-Vertical Spectral Ratio (RVSR). The results of the analyses performed while considering these approaches (completely different both in terms of field procedures and data analysis) appear extremely consistent thus mutually validating their performances. Pros and cons of each approach are summarized both in terms of computational aspects as well as with respect to practical considerations regarding the specific character of the pertinent field procedures.

  18. The Surface Density Profile of the Galactic Disk from the Terminal Velocity Curve

    NASA Astrophysics Data System (ADS)

    McGaugh, Stacy S.

    2016-01-01

    The mass distribution of the Galactic disk is constructed from the terminal velocity curve and the mass discrepancy-acceleration relation. Mass models numerically quantifying the detailed surface density profiles are tabulated. For R0 = 8 kpc, the models have stellar mass 5 < M* < 6 × 1010 {M}⊙ , scale length 2.0 ≤ Rd ≤ 2.9 kpc, LSR circular velocity 222 ≤ Θ0 ≤ 233 {km} {{{s}}}-1, and solar circle stellar surface density 34 ≤ Σd(R0) ≤ 61 {M}⊙ {{pc}}-2. The present interarm location of the solar neighborhood may have a somewhat lower stellar surface density than average for the solar circle. The Milky Way appears to be a normal spiral galaxy that obeys scaling relations like the Tully-Fisher relation, the size-mass relation, and the disk maximality-surface brightness relation. The stellar disk is maximal, and the spiral arms are massive. The bumps and wiggles in the terminal velocity curve correspond to known spiral features (e.g., the Centaurus arm is a ˜50% overdensity). The rotation curve switches between positive and negative over scales of hundreds of parsecs. The rms amplitude {< {| {dV}/{dR}| }2> }1/2≈ 14 {km} {{{s}}}-1 {{kpc}}-1, implying that commonly neglected terms in the Jeans equations may be nonnegligible. The spherically averaged local dark matter density is ρ0,DM ≈ 0.009 {M}⊙ {{pc}}-3 (0.34 {GeV} {{cm}}-3). Adiabatic compression of the dark matter halo may help reconcile the Milky Way with the c-V200 relation expected in ΛCDM while also helping to mitigate the too-big-to-fail problem, but it remains difficult to reconcile the inner bulge/bar-dominated region with a cuspy halo. We note that NGC 3521 is a near twin to the Milky Way, having a similar luminosity, scale length, and rotation curve.

  19. Evolution of density and velocity profiles of dark matter and dark energy in spherical voids

    NASA Astrophysics Data System (ADS)

    Novosyadlyj, Bohdan; Tsizh, Maksym; Kulinich, Yurij

    2017-02-01

    We analyse the evolution of cosmological perturbations which leads to the formation of large isolated voids in the Universe. We assume that initial perturbations are spherical and all components of the Universe (radiation, matter and dark energy) are continuous media with ideal fluid energy-momentum tensors, which interact only gravitationally. Equations of the evolution of perturbations for every component in the comoving to cosmological background reference frame are obtained from equations of energy and momentum conservation and Einstein's ones and are integrated numerically. Initial conditions are set at the early stage of evolution in the radiation-dominated epoch, when the scale of perturbation is much larger than the particle horizon. Results show how the profiles of density and velocity of matter and dark energy are formed and how they depend on parameters of dark energy and initial conditions. In particular, it is shown that final matter density and velocity amplitudes change within range ˜4-7 per cent when the value of equation-of-state parameter of dark energy w vary in the range from -0.8 to -1.2, and change within ˜1 per cent only when the value of effective sound speed of dark energy vary over all allowable range of its values.

  20. Multiple Velocity Profile Measurements in Hypersonic Flows using Sequentially-Imaged Fluorescence Tagging

    NASA Technical Reports Server (NTRS)

    Bathel, Brett F.; Danehy, Paul M.; Inmian, Jennifer A.; Jones, Stephen B.; Ivey, Christopher B.; Goyne, Christopher P.

    2010-01-01

    Nitric-oxide planar laser-induced fluorescence (NO PLIF) was used to perform velocity measurements in hypersonic flows by generating multiple tagged lines which fluoresce as they convect downstream. For each laser pulse, a single interline, progressive scan intensified CCD camera was used to obtain separate images of the initial undelayed and delayed NO molecules that had been tagged by the laser. The CCD configuration allowed for sub-microsecond acquisition of both images, resulting in sub-microsecond temporal resolution as well as sub-mm spatial resolution (0.5-mm x 0.7-mm). Determination of axial velocity was made by application of a cross-correlation analysis of the horizontal shift of individual tagged lines. Quantification of systematic errors, the contribution of gating/exposure duration errors, and influence of collision rate on fluorescence to temporal uncertainty were made. Quantification of the spatial uncertainty depended upon the analysis technique and signal-to-noise of the acquired profiles. This investigation focused on two hypersonic flow experiments: (1) a reaction control system (RCS) jet on an Orion Crew Exploration Vehicle (CEV) wind tunnel model and (2) a 10-degree half-angle wedge containing a 2-mm tall, 4-mm wide cylindrical boundary layer trip. The experiments were performed at the NASA Langley Research Center's 31-inch Mach 10 wind tunnel.

  1. An acoustic doppler current profiler survey of flow velocities in St. Clair River, a connecting channel of the Great Lakes

    USGS Publications Warehouse

    Holtschlag, David J.; Koschik, John A.

    2003-01-01

    Acoustic Doppler current profilers (ADCP) were used to measure flow velocities in St. Clair River during a survey in May and June of 2002, as part of a study to assess the susceptibility of public water intakes to contaminants on the St. Clair-Detroit River Waterway. The survey provides 2.7 million point velocity measurements at 104 cross sections. Sections are spaced about 1,630 ft apart along the river from Port Huron to Algonac, Michigan, a distance of 28.6 miles. Two transects were obtained at each cross section, one in each direction across the river. Along each transect, velocity profiles were obtained 2-4 ft apart. At each velocity profile, average water velocity data were obtained at 1.64 ft intervals of depth. The raw position and velocity data from the ADCP field survey were adjusted for local magnetic anomalies using global positioning system (GPS) measurements at the end points of the transects. The adjusted velocity and ancillary data can be retrieved through the internet and extracted to column-oriented data files.

  2. An acoustic doppler current profiler survey of flow velocities in Detroit River, a connecting channel of the Great Lakes

    USGS Publications Warehouse

    Holtschlag, David J.; Koschik, John A.

    2003-01-01

    Acoustic Doppler current profilers (ADCP) were used to survey flow velocities in Detroit River from July 8-19, 2002, as part of a study to assess the susceptibility of public water intakes to contaminants on the St. Clair-Detroit River Waterway. More than 3.5 million point velocities were measured at 130 cross sections. Cross sections were generally spaced about 1,800 ft apart along the river from the head of Detroit River at the outlet of Lake St. Clair to the mouth of Detroit River on Lake Erie. Two transects were surveyed at each cross section, one in each direction across the river. Along each transect, velocity profiles were generally obtained 0.8-2.2 ft apart. At each velocity profile, average water velocity data were obtained at 1.64 ft intervals of depth. The raw position and velocity data from the ADCP field survey were adjusted for local magnetic anomalies using global positioning system (GPS) measurements at the end points of the transects. The adjusted velocity and ancillary data can be retrieved though the internet and extracted to column-oriented data files.

  3. Effect of Wind Tunnel Air Velocity on VOC Flux from Standard Solutions and CAFO Manure/Wastewater

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Researchers and practitioners have used wind tunnels and flux chambers to quantify the flux of volatile organic compounds (VOCs), ammonia, and hydrogen sulfide and estimate emission factors from animal feeding operations (AFOs) without accounting for effects of air velocity or sweep air flow rate. L...

  4. Validation of a CFD Model by Using 3D Sonic Anemometers to Analyse the Air Velocity Generated by an Air-Assisted Sprayer Equipped with Two Axial Fans

    PubMed Central

    García-Ramos, F. Javier; Malón, Hugo; Aguirre, A. Javier; Boné, Antonio; Puyuelo, Javier; Vidal, Mariano

    2015-01-01

    A computational fluid dynamics (CFD) model of the air flow generated by an air-assisted sprayer equipped with two axial fans was developed and validated by practical experiments in the laboratory. The CFD model was developed by considering the total air flow supplied by the sprayer fan to be the main parameter, rather than the outlet air velocity. The model was developed for three air flows corresponding to three fan blade settings and assuming that the sprayer is stationary. Actual measurements of the air velocity near the sprayer were taken using 3D sonic anemometers. The workspace sprayer was divided into three sections, and the air velocity was measured in each section on both sides of the machine at a horizontal distance of 1.5, 2.5, and 3.5 m from the machine, and at heights of 1, 2, 3, and 4 m above the ground The coefficient of determination (R2) between the simulated and measured values was 0.859, which demonstrates a good correlation between the simulated and measured data. Considering the overall data, the air velocity values produced by the CFD model were not significantly different from the measured values. PMID:25621611

  5. Changes in the Force-Velocity Mechanical Profile After Short Resistance Training Programmes Differing in Set Configurations.

    PubMed

    Iglesias-Soler, Eliseo; Fernández-Del-Olmo, Miguel; Mayo, Xián; Fariñas, Juan; Río-Rodríguez, Dan; Carballeira, Eduardo; Carnero, Elvis A; Standley, Robert A; Giráldez-García, Manuel A; Dopico-Calvo, Xurxo; Tuimil, Jose Luis

    2016-12-05

    The main aim of this study was to analyse the effect of resistance training programs differing in set configuration on mechanical force-velocity profiles. Thirteen participants performed ten unilateral knee extension training sessions over 5 weeks. Each limb was randomised to one of the following set configurations: traditional (4 sets of 8 repetitions at maximum intended velocity, 10RM load, 3-min pause between sets), and inter-repetition rest (32 maximum intended velocity repetitions, 10RM load, 17.4 s of rest between each repetition). Velocity of each repetition was recorded throughout the programme. Before, and after training, individual linear force-velocities were calculated, and the following parameters were obtained: force, and velocity axis intercept, slope, and estimated maximum power. Mean velocity was higher throughout the programme for inter-repetition rest configuration (0.54±0.01 vs. 0.48±0.01 m.s(-1) for inter-repetition rest, and traditional configuration respectively; main effect of set configuration: p<0.001). There was a significant increase in force and velocity intercepts, but a steeper negative slope after both training protocols (main effect of time: p<0.001 for every variable). Differences in resistance training velocity did not affect the adaptations. Our results suggest that in a short-term programme maximum intended rather than actual velocity is a key factor to modulate strength adaptations.

  6. Vertical profiles of the 3-D wind velocity retrieved from multiple wind lidars performing triple range-height-indicator scans

    DOE PAGES

    Debnath, Mithu; Iungo, G. Valerio; Ashton, Ryan; ...

    2017-02-06

    Vertical profiles of 3-D wind velocity are retrieved from triple range-height-indicator (RHI) scans performed with multiple simultaneous scanning Doppler wind lidars. This test is part of the eXperimental Planetary boundary layer Instrumentation Assessment (XPIA) campaign carried out at the Boulder Atmospheric Observatory. The three wind velocity components are retrieved and then compared with the data acquired through various profiling wind lidars and high-frequency wind data obtained from sonic anemometers installed on a 300 m meteorological tower. The results show that the magnitude of the horizontal wind velocity and the wind direction obtained from the triple RHI scans are generally retrieved with goodmore » accuracy. However, poor accuracy is obtained for the evaluation of the vertical velocity, which is mainly due to its typically smaller magnitude and to the error propagation connected with the data retrieval procedure and accuracy in the experimental setup.« less

  7. Vertical profiles of the 3-D wind velocity retrieved from multiple wind lidars performing triple range-height-indicator scans

    SciTech Connect

    Debnath, Mithu; Iungo, G. Valerio; Ashton, Ryan; Brewer, W. Alan; Choukulkar, Aditya; Delgado, Ruben; Lundquist, Julie K.; Shaw, William J.; Wilczak, James M.; Wolfe, Daniel

    2017-01-01

    Vertical profiles of 3-D wind velocity are retrieved from triple range-height-indicator (RHI) scans performed with multiple simultaneous scanning Doppler wind lidars. This test is part of the eXperimental Planetary boundary layer Instrumentation Assessment (XPIA) campaign carried out at the Boulder Atmospheric Observatory. The three wind velocity components are retrieved and then compared with the data acquired through various profiling wind lidars and high-frequency wind data obtained from sonic anemometers installed on a 300 m meteorological tower. The results show that the magnitude of the horizontal wind velocity and the wind direction obtained from the triple RHI scans are generally retrieved with good accuracy. However, poor accuracy is obtained for the evaluation of the vertical velocity, which is mainly due to its typically smaller magnitude and to the error propagation connected with the data retrieval procedure and accuracy in the experimental setup.

  8. Vertical profiles of the 3-D wind velocity retrieved from multiple wind lidars performing triple range-height-indicator scans

    NASA Astrophysics Data System (ADS)

    Debnath, Mithu; Valerio Iungo, G.; Ashton, Ryan; Brewer, W. Alan; Choukulkar, Aditya; Delgado, Ruben; Lundquist, Julie K.; Shaw, William J.; Wilczak, James M.; Wolfe, Daniel

    2017-02-01

    Vertical profiles of 3-D wind velocity are retrieved from triple range-height-indicator (RHI) scans performed with multiple simultaneous scanning Doppler wind lidars. This test is part of the eXperimental Planetary boundary layer Instrumentation Assessment (XPIA) campaign carried out at the Boulder Atmospheric Observatory. The three wind velocity components are retrieved and then compared with the data acquired through various profiling wind lidars and high-frequency wind data obtained from sonic anemometers installed on a 300 m meteorological tower. The results show that the magnitude of the horizontal wind velocity and the wind direction obtained from the triple RHI scans are generally retrieved with good accuracy. However, poor accuracy is obtained for the evaluation of the vertical velocity, which is mainly due to its typically smaller magnitude and to the error propagation connected with the data retrieval procedure and accuracy in the experimental setup.

  9. Simultaneous measurement of temperature and velocity fields in convective air flows

    NASA Astrophysics Data System (ADS)

    Schmeling, Daniel; Bosbach, Johannes; Wagner, Claus

    2014-03-01

    Thermal convective air flows are of great relevance in fundamental studies and technical applications such as heat exchangers or indoor ventilation. Since these kinds of flow are driven by temperature gradients, simultaneous measurements of instantaneous velocity and temperature fields are highly desirable. A possible solution is the combination of particle image velocimetry (PIV) and particle image thermography (PIT) using thermochromic liquid crystals (TLCs) as tracer particles. While combined PIV and PIT is already state of the art for measurements in liquids, this is not yet the case for gas flows. In this study we address the adaptation of the measuring technique to gaseous fluids with respect to the generation of the tracer particles, the particle illumination and the image filtering process. Results of the simultaneous PIV/PIT stemming from application to a fluid system with continuous air exchange are presented. The measurements were conducted in a cuboidal convection sample with air in- and outlet at a Rayleigh number Ra ≈ 9.0 × 107. They prove the feasibility of the method by providing absolute and relative temperature accuracies of σT = 0.19 K and σΔT = 0.06 K, respectively. Further open issues that have to be addressed in order to mature the technique are identified.

  10. Solutions of the Bogoliubov-de Gennes equation with position dependent Fermi-velocity and gap profiles

    NASA Astrophysics Data System (ADS)

    Presilla, M.; Panella, O.; Roy, P.

    2017-02-01

    It is shown that bound state solutions of the one dimensional Bogoliubov-de Gennes (BdG) equation may exist when the Fermi velocity becomes dependent on the space coordinate. The existence of bound states in continuum (BIC) like solutions has also been confirmed both in the normal phase as well as in the super-conducting phase. We also show that a combination of Fermi velocity and gap parameter step-like profiles provides scattering solutions with normal reflection and transmission.

  11. Provide a suitable range to include the thermal creeping effect on slip velocity and temperature jump of an air flow in a nanochannel by lattice Boltzmann method

    NASA Astrophysics Data System (ADS)

    Karimipour, Arash

    2017-01-01

    The thermal creeping effect on slip velocity of air forced convection through a nanochannel is studied for the first time by using a lattice Boltzmann method. The nanochannel side walls are kept hot while the cold inlet air streams along them. The computations are presented for the wide range of Reynolds number, Knudsen number and Eckert number while slip velocity and temperature jump effects are involved. Moreover appropriate validations are performed versus previous works concerned the micro-nanoflows. The achieved results are shown as the velocity and temperature profiles at different cross sections, streamlines and isotherms and also the values of slip velocity and temperature jump along the nanochannel walls. The ability of the lattice Boltzmann method to simulate the thermal creeping effects on hydrodynamic and thermal domains of flow is shown at this study; so that its effects should be involved at lower values of Eckert number and higher values of Reynolds number especially at entrance region where the most temperature gradient exists.

  12. Cross-correlation velocimetry for measurement of velocity and temperature profiles in low-speed, turbulent, nonisothermal flows

    SciTech Connect

    Motevalli, V. ); Marks, C.H. ); McCaffrey, B.J. )

    1992-05-01

    A technique utilizing thermocouple pairs as sensors to measure velocity and temperature profiles in low-speed, turbulent, nonisothermal flows is described here. In this technique, Cross-Correlation Velocimetry (CCV), the temperature-time records from a pair of thermocouples, one downstream of the other, are cross-correlated to determine the flow's preferred mean velocity while temperature is measured directly. The velocity measurements have undergone extensive verification using hotwire, pitot tube, and Laser-Doppler Velocimetry to determine the degree of confidence in this technique. This work demonstrates that the CCV technique is quite reliable and can measure the mean preferred component of the convective velocity with better than {plus minus}5 percent certainty. Application of this technique to the measurement of velocities in a ceiling jet induced by a fire plume is briefly presented here.

  13. Cause and solution for false upstream boat velocities measured with a StreamPro acoustic doppler current profiler

    USGS Publications Warehouse

    Mueller, David S.; Rehmel, Mike S.; Wagner, Chad R.

    2007-01-01

    In 2003, Teledyne RD Instruments introduced the StreamPro acoustic Doppler current profiler which does not include an internal compass. During stationary moving-bed tests the StreamPro often tends to swim or kite from the end of the tether (the instrument rotates then moves laterally in the direction of the rotation). Because the StreamPro does not have an internal compass, it cannot account for the rotation. This rotation and lateral movement of the StreamPro on the end of the tether generates a false upstream velocity, which cannot be easily distinguished from a moving-bed bias velocity. A field test was completed to demonstrate that this rotation and lateral movement causes a false upstream boat velocity. The vector dot product of the boat velocity and the unit vector of the depth-averaged water velocity is shown to be an effective method to account for the effect of the rotation and lateral movement.

  14. Stabilized three-stage oxidation of DME/air mixture in a micro flow reactor with a controlled temperature profile

    SciTech Connect

    Oshibe, Hiroshi; Nakamura, Hisashi; Tezuka, Takuya; Hasegawa, Susumu; Maruta, Kaoru

    2010-08-15

    Ignition and combustion characteristics of a stoichiometric dimethyl ether (DME)/air mixture in a micro flow reactor with a controlled temperature profile which was smoothly ramped from room temperature to ignition temperature were investigated. Special attention was paid to the multi-stage oxidation in low temperature condition. Normal stable flames in a mixture flow in the high velocity region, and non-stationary pulsating flames and/or repetitive extinction and ignition (FREI) in the medium velocity region were experimentally confirmed as expected from our previous study on a methane/air mixture. In addition, stable double weak flames were observed in the low velocity region for the present DME/air mixture case. It is the first observation of stable double flames by the present methodology. Gas sampling was conducted to obtain major species distributions in the flow reactor. The results indicated that existence of low-temperature oxidation was conjectured by the production of CH{sub 2}O occured in the upstream side of the experimental first luminous flame, while no chemiluminescence from it was seen. One-dimensional computation with detailed chemistry and transport was conducted. At low mixture velocities, three-stage oxidation was confirmed from profiles of the heat release rate and major chemical species, which was broadly in agreement with the experimental results. Since the present micro flow reactor with a controlled temperature profile successfully presented the multi-stage oxidations as spatially separated flames, it is shown that this flow reactor can be utilized as a methodology to separate sets of reactions, even for other practical fuels, at different temperature. (author)

  15. Effects of CO2/N2 dilution on laminar burning velocity of stoichiometric DME-air mixture at elevated temperatures.

    PubMed

    Mohammed, Abdul Naseer; Juhany, Khalid A; Kumar, Sudarshan; Kishore, V Ratna; Mohammad, Akram

    2017-03-21

    The laminar burning velocity of CO2/N2 diluted stoichiometric dimethyl ether (DME) air mixtures is determined experimentally at atmospheric pressure and elevated mixture temperatures using a mesoscale high aspect-ratio diverging channel with inlet dimensions of 25mm×2mm. In this method, planar flames at different initial temperatures (Tu) were stabilized inside the channel using an external electric heater. The magnitude of burning velocities was acquired by measuring the flame position and initial temperature. The mass conservation of the mixture entering the inlet and the stationary planar flame front is applied to obtain the laminar burning velocity. Laminar burning velocity at different initial mixture temperatures is plotted with temperature ratio (Tu/Tu,o), where a reference temperature (Tu,o) of 300K is used. Enhancement in the laminar burning velocity is observed with mixture temperature for DME-air mixtures with CO2 and N2 dilutions. A significant decrease in the burning velocity and slight increase in temperature exponent of the stoichiometric DME-air mixture was observed with dilution at same temperatures. The addition of CO2 has profound influence when compared to N2 addition on both burning velocity and temperature exponent.

  16. P.88 Regional Precipitation Forecast with Atmospheric Infrared Sounder (AIRS) Profiles

    NASA Technical Reports Server (NTRS)

    Chou, Shih-Hung; Zavodsky, Bradley; Jedlovec, Gary

    2010-01-01

    Prudent assimulation of AIRS thermodynamic profiles and quality indicators can improve initial conditions for regional weather models. In general, AIRS-enhanced analysis more closely resembles radiosondes than the CNTL; forecasts with AIRS profiles are generally closer to NAM analyses than CNTL for sensible weather parameters (not shown here). Assimilation of AIRS leads to an overall QPF improvement in 6-h accumulated precipitation forecases. Including AIRS profiles in assimilation process enhances the low-level instability and produces stronger updrafts and a better precipitation forecast than the CNTL run.

  17. Analysis of possible improvement of acceleration of a high-velocity air-breathing flying vehicle

    NASA Astrophysics Data System (ADS)

    Goonko, Yu. P.; Mazhul, I. I.

    2008-09-01

    Results of parametric calculations of the total aeropropulsive characteristics and characteristics of acceleration of a small-scale high-velocity flying vehicle with an air-breathing engine are presented. Integral parameters of acceleration from the flight Mach number M∞ = 4 to M∞ = 7 are determined, namely, the time required fuel stock, and range. A schematic configuration of the vehicle is considered, which allows studying the basic parameters, such as the forebody shape, the angles of surfaces of compression of the stream captured by the inlet, angles of external aerodynamic surfaces of the airframe, relative planform area of the wing panels, and relative area of the nozzle cross section. A comparative estimate of the effect of these parameters shows that it is possible to improve the characteristics of acceleration of vehicles of the type considered.

  18. Effects of light intensity and air velocity on air temperature, water vapor pressure, and CO2 concentration inside a plant canopy under an artificial lighting condition.

    PubMed

    Kitaya, Y; Shibuya, T; Kozai, T; Kubota, C

    1998-01-01

    In order to characterize environmental variables inside a plant canopy under artificial lighting in the CELSS, we investigated the effects of light intensity and air velocity on air temperature, water vapor pressure, and CO2 concentration inside a plant canopy. Under a PPF of 500 micromoles m-2 s-1, air temperature was 2-3 degrees C higher, water vapor pressure was 0.6 kPa higher, and CO2 concentration was 25-35 micromoles mol-1 lower at heights ranging from 0 to 30 mm below the canopy than at a height 60 mm above the canopy. Increasing the PPF increased air temperature and water vapor pressure and decreased CO2 concentration inside the canopy. The air temperature was lower and the CO2 concentration was higher inside the canopy at an air velocity of 0.3 m s-1 than at an air velocity of 0.1 m s-1. The environmental variables inside the canopy under a high light intensity were characterized by higher air temperature, higher vapor pressure, and lower CO2 concentration than those outside the canopy.

  19. Estimation of volume flow in curved tubes based on analytical and computational analysis of axial velocity profiles

    NASA Astrophysics Data System (ADS)

    Verkaik, A. C.; Beulen, B. W. A. M. M.; Bogaerds, A. C. B.; Rutten, M. C. M.; van de Vosse, F. N.

    2009-02-01

    To monitor biomechanical parameters related to cardiovascular disease, it is necessary to perform correct volume flow estimations of blood flow in arteries based on local blood velocity measurements. In clinical practice, estimates of flow are currently made using a straight-tube assumption, which may lead to inaccuracies since most arteries are curved. Therefore, this study will focus on the effect of curvature on the axial velocity profile for flow in a curved tube in order to find a new volume flow estimation method. The study is restricted to steady flow, enabling the use of analytical methods. First, analytical approximation methods for steady flow in curved tubes at low Dean numbers (Dn) and low curvature ratios (δ) are investigated. From the results a novel volume flow estimation method, the cos θ-method, is derived. Simulations for curved tube flow in the physiological range (1≤Dn≤1000 and 0.01≤δ≤0.16) are performed with a computational fluid dynamics (CFD) model. The asymmetric axial velocity profiles of the analytical approximation methods are compared with the velocity profiles of the CFD model. Next, the cos θ-method is validated and compared with the currently used Poiseuille method by using the CFD results as input. Comparison of the axial velocity profiles of the CFD model with the approximations derived by Topakoglu [J. Math. Mech. 16, 1321 (1967)] and Siggers and Waters [Phys. Fluids 17, 077102 (2005)] shows that the derived velocity profiles agree very well for Dn≤50 and are fair for 50100), no analytical approximation method exists. In the position of the maximum axial velocity, a shift toward the inside of the curve is observed for low Dean numbers, while for high Dean numbers, the position of the maximum velocity is located at the outer curve. When the position of

  20. Nonlocal stochastic mixing-length theory and the velocity profile in the turbulent boundary layer

    NASA Astrophysics Data System (ADS)

    Dekker, H.; de Leeuw, G.; Maassen van den Brink, A.

    1995-02-01

    Turbulence mixing by finite size eddies will be treated by means of a novel formulation of nonlocal K-theory, involving sample paths and a stochastic closure hypothesis, which implies a well defined recipe for the calculation of sampling and transition rates. The connection with the general theory of stochastic processes will be established. The relation with other nonlocal turbulence models (e.g. transilience and spectral diffusivity theory) is also discussed. Using an analytical sampling rate model (satisfying exchange) the theory is applied to the boundary layer (using a scaling hypothesis), which maps boundary layer turbulence mixing of scalar densities onto a nondiffusive (Kubo-Anderson or kangaroo) type stochastic process. The resulting transpport equation for longitudinal momentum P x ≡ ϱ U is solved for a unified description of both the inertial and the viscous sublayer including the crossover. With a scaling exponent ε ≈ 0.58 (while local turbulence would amount to ε → ∞) the velocity profile U+ = ƒ(y +) is found to be in excellent agreement with the experimental data. Inter alia (i) the significance of ε as a turbulence Cantor set dimension, (ii) the value of the integration constant in the logarithmic region (i.e. if y+ → ∞), (iii) linear timescaling, and (iv) finite Reynolds number effects will be investigated. The (analytical) predictions of the theory for near-wall behaviour (i.e. if y+ → 0) of fluctuating quantities also perfectly agree with recent direct numerical simulations.

  1. Vertical velocity and turbulence aspects during Mistral events as observed by UHF wind profilers

    NASA Astrophysics Data System (ADS)

    Caccia, J.; Guénard, V.; Benech, B.; Campistron, B.; Drobinski, P.

    2004-11-01

    The general purpose of this paper is to experimentally study mesoscale dynamical aspects of the Mistral in the coastal area located at the exit of the Rhône-valley. The Mistral is a northerly low-level flow blowing in southern France along the Rhône-valley axis, located between the French Alps and the Massif Central, towards the Mediterranean Sea. The experimental data are obtained by UHF wind profilers deployed during two major field campaigns, MAP (Mesoscale Alpine Program) in autumn 1999, and ESCOMPTE (Expérience sur Site pour COntraindre les Modèles de Pollution atmosphériques et de Transports d'Emission) in summer 2001. Thanks to the use of the time evolution of the vertical profile of the horizontal wind vector, recent works have shown that the dynamics of the Mistral is highly dependent on the season because of the occurrence of specific synoptic patterns. In addition, during summer, thermal forcing leads to a combination of sea breeze with Mistral and weaker Mistral due to the enhanced friction while, during autumn, absence of convective turbulence leads to substantial acceleration as low-level jets are generated in the stably stratified planetary boundary layer. At the exit of the Rhône valley, the gap flow dynamics dominates, whereas at the lee of the Alps, the dynamics is driven by the relative contribution of "flow around" and "flow over" mechanisms, upstream of the Alps. This paper analyses vertical velocity and turbulence, i.e. turbulent dissipation rate, with data obtained by the same UHF wind profilers during the same Mistral events. In autumn, the motions are found to be globally and significantly subsident, which is coherent for a dry, cold and stable flow approaching the sea, and the turbulence is found to be of pure dynamical origin (wind shears and mountain/lee wave breaking), which is coherent with non-convective situations. In summer, due to the ground heating and to the interactions with thermal circulation, the vertical motions are

  2. The influence of bubble plumes on air-seawater gas transfer velocities

    SciTech Connect

    Asher, W.E.; Karle, L.M.; Higgins, B.J.

    1995-07-01

    Air-sea gas exchange is an important process in the geochemical cycling of carbon dioxide (CO{sub 2}). The air-sea flux of CO{sub 2} is determined in part by the physical forcing functions, which are parameterized in terms of the air-sea transfer velocity, k{sub L}. Past studies have attempted to correlate k{sub L} with wind speed, U. Because strong winds occur in ocean regions thought to be important sources or sinks of CO{sub 2}, accurate knowledge of k{sub L} at high U is important in estimating the global air-sea flux of CO{sub 2}. Better understanding of the physical processes affecting gas transfer at large U will increase the accuracy in estimating k{sub L} in ocean regions with high CO{sub 2}, fluxes. Increased accuracy in estimating k{sub L} will increase the accuracy in calculating the net global air-sea CO{sub 2} flux and provide more accurate boundary and initial conditions for global ocean carbon cycle models. High wind speeds are associated with the presence of whitecaps, which can increase the gas flux by generating turbulence, disrupting surface films, and creating bubble plumes. Bubble plumes will create additional turbulence, prolong the surface disruption, and transfer gas to or from individual bubbles while they are beneath the surface. These turbulence and bubble processes very effectively promote gas transfer. Because of this, it is postulated that breaking waves, if present, will dominate non-whitecap related gas exchange. Under this assumption, k{sub L} Will increase linearly with increasing fractional area whitecap coverage, W{sub c}. In support of this, researchers found k{sub L} measured in a whitecap simulation tank (WSI) was linearly correlated with bubble plume coverage, B{sub c} (the laboratory analog of W{sub c}). However, it is not definitively known how the presence of breaking waves and bubble plumes affect the dependence of k{sub L} on Schmidt number, Sc, and aqueous-phase solubility, {alpha}.

  3. Measuring OutdoorAir Intake Rates Using Electronic Velocity Sensors at Louvers and Downstream of Airflow Straighteners

    SciTech Connect

    Fisk, William; Sullivan, Douglas; Cohen, Sebastian; Han, Hwataik

    2008-10-01

    Practical and accurate technologies are needed for continuously measuring and controlling outdoor air (OA) intake rates in commercial building heating, ventilating, and air conditioning (HVAC) systems. This project evaluated two new measurement approaches. Laboratory experiments determined that OA flow rates were measurable with errors generally less than 10percent using electronic air velocity probes installed between OA intake louver blades or at the outlet face of louvers. High accuracy was maintained with OA flow rates as low as 15percent of the maximum for the louvers. Thus, with this measurement approach HVAC systems do not need separate OA intakes for minimum OA supply. System calibration parameters are required for each unique combination of louver type and velocity sensor location but calibrations are not necessary for each system installation. The research also determined that the accuracy of measuring OA flow rates with velocity probes located in the duct downstream of the intake louver was not improved by installing honeycomb airflow straighteners upstream of the probes. Errors varied with type of upstream louver, were as high as 100percent, and were often greater than 25percent. In conclusion, use of electronic air velocity probes between the blades of OA intake louvers or at the outlet face of louvers is a highly promising means of accurately measuring rates of OA flow into HVAC systems. The use of electronic velocity probes downstream of airflow straighteners is less promising, at least with the relatively small OA HVAC inlet systems employed in this research.

  4. Velocity profiles and plug zones in a free surface viscoplastic flow : experimental study and comparison to shallow flow models

    NASA Astrophysics Data System (ADS)

    Freydier, Perrine; Chambon, Guillaume; Naaim, Mohamed

    2016-04-01

    Rheological studies concerning natural muddy debris flows have shown that these materials can be modelled as non-Newtonian viscoplastic fluids. These complex flows are generally represented using models based on a depth-integrated approach (Shallow Water) that take into account closure terms depending on the shape of the velocity profile. But to date, there is poor knowledge about the shape of velocity profiles and the position of the interface between sheared and unsheared regions (plug) in these flows, especially in the vicinity of the front. In this research, the internal dynamics of a free-surface viscoplastic flow down an inclined channel is investigated and compared to the predictions of a Shallow Water model based on the lubrication approximation. Experiments are conducted in an inclined channel whose bottom is constituted by an upward-moving conveyor belt with controlled velocity, which allows generating and observing gravity-driven stationary surges in the laboratory frame. Carbopol microgel has been used as a homogeneous and transparent viscoplastic fluid. High-resolution measurements of velocity field is performed through optical velocimetry techniques both in the uniform zone and within the front zone where flow thickness is variable and where recirculation takes place. Specific analyses have been developed to determine the position of the plug within the surge. Flow height is accessible through image processing and ultrasonic sensors. Sufficiently far from the front, experimental results are shown to be in good agreement with theoretical predictions regarding the velocity profiles and the flow height evolution. In the vicinity of the front, however, analysis of measured velocity profiles shows an evolution of the plug different from that predicted by lubrication approximation. Accordingly, the free surface shape also deviates from the predictions of the classical Shallow Water model. These results highlight the necessity to take into account higher

  5. An application of particle image velocimetry to the direct measurement of laminar burning velocity in homogeneous propane-air mixtures

    SciTech Connect

    Zhou, M.; Garner, C.P.

    1995-12-31

    An experiment is described for the direct measurement of laminar burning velocity within an optically accessed cylindrical combustion chamber. The laminar burning velocity was determined directly as the difference between the flame propagation speed and the unburned gas velocity immediately ahead of the flame front. Particle Image Velocimetry (PIV) has been applied to measure the unburned gas velocity field. The local flame speed and flame front position were determined from a pair of ionization probes in conjunction with the simultaneous PIV measurement. The laminar burning velocity of propane-air mixtures initially at atmospheric condition for different equivalence ratios ranging from 0.7--1.4 are presented. Close agreement with other measurements and predicted results was found.

  6. The Effect of the Pre-detonation Stellar Internal Velocity Profile on the Nucleosynthetic Yields in Type Ia Supernova

    NASA Astrophysics Data System (ADS)

    Kim, Yeunjin; Jordan, G. C., IV; Graziani, Carlo; Meyer, B. S.; Lamb, D. Q.; Truran, J. W.

    2013-07-01

    A common model of the explosion mechanism of Type Ia supernovae is based on a delayed detonation of a white dwarf. A variety of models differ primarily in the method by which the deflagration leads to a detonation. A common feature of the models, however, is that all of them involve the propagation of the detonation through a white dwarf that is either expanding or contracting, where the stellar internal velocity profile depends on both time and space. In this work, we investigate the effects of the pre-detonation stellar internal velocity profile and the post-detonation velocity of expansion on the production of α-particle nuclei, including 56Ni, which are the primary nuclei produced by the detonation wave. We perform one-dimensional hydrodynamic simulations of the explosion phase of the white dwarf for center and off-center detonations with five different stellar velocity profiles at the onset of the detonation. In order to follow the complex flows and to calculate the nucleosynthetic yields, approximately 10,000 tracer particles were added to every simulation. We observe two distinct post-detonation expansion phases: rarefaction and bulk expansion. Almost all the burning to 56Ni occurs only in the rarefaction phase, and its expansion timescale is influenced by pre-existing flow structure in the star, in particular by the pre-detonation stellar velocity profile. We find that the mass fractions of the α-particle nuclei, including 56Ni, are tight functions of the empirical physical parameter ρup/v down, where ρup is the mass density immediately upstream of the detonation wave front and v down is the velocity of the flow immediately downstream of the detonation wave front. We also find that v down depends on the pre-detonation flow velocity. We conclude that the properties of the pre-existing flow, in particular the internal stellar velocity profile, influence the final isotopic composition of burned matter produced by the detonation.

  7. Velocity Profiles of Galaxies with Claimed Black-Holes - Part Three - Observations and Models for M87

    NASA Astrophysics Data System (ADS)

    van der Marel, R. P.

    1994-09-01

    We report on high-S/N subarcsec resolution spectra of M87, obtained with the 4.2-m William Herschel Telescope in the spectral regions around the blue G-band and the IR Ca II triplet. From the spectra we determine the line strengths, the mean and dispersion of the best-fitting Gaussian velocity profiles (i.e. the line-of-sight velocity distributions) and the Gauss-Hermite moments h_3_,...h_6_ that measure deviations from a Gaussian. We find that the main results derived from the two spectral regions agree, in contradiction to recent measurements by Jarvis & Melnick. The observed line strengths have a central minimum in both spectral regions and are consistent with the central luminosity `spike' of M87 being completely non-thermal. The coefficients h_3_,...h_6_ are close to zero at all radii. The velocity dispersion rises from ~270 km s^-1^ at ~15 arcsec to ~305 km s^-1^ at ~5 arcsec, and then to ~400 km s^-1^ at 0.5 arcsec. We model the observed velocity dispersions by solving the Jeans equation for hydrostatic equilibrium. Radial anisotropy (β ~ 0.5) is required in the outer parts to fit the observed velocity dispersion gradient. Near the centre, the data can still be fitted equally well with radially anisotropic models without a central black hole as they can be with less anisotropic models with a central black hole of mass M_BH_ <~ 5 x 10^9^ M_sun_. However, the radially anisotropic Jeans models without a central black hole need not necessarily correspond to a positive and stable distribution function. We study the central velocity profile of isotropic dynamical models with a central black hole. The wings of the velocity profile are more extended than those of a Gaussian. This is due to the stars that orbit close to the hole at high velocities. The wings contribute significantly to the normalization and the dispersion of the velocity profile. A Gaussian fit to the velocity profile is insensitive to the wings, and thus underestimates both the line strength γ and

  8. Discrete velocity models for multicomponent mixtures and polyatomic molecules without nonphysical collision invariants and shock profiles

    NASA Astrophysics Data System (ADS)

    Bernhoff, Niclas

    2016-11-01

    An important aspect of constructing discrete velocity models (DVMs) for the Boltzmann equation is to obtain the right number of collision invariants. It is a well-known fact that, in difference to in the continuous case, DVMs can have extra collision invariants, so called spurious collision invariants, in plus to the physical ones. A DVM with only physical collision invariants, and so without spurious ones, is called normal. The construction of such normal DVMs has been studied a lot in the literature for single species as well as for binary mixtures. For binary mixtures also the concept of supernormal DVMs has been introduced by Bobylev and Vinerean. Supernormal DVMs are defined as normal DVMs such that both restrictions to the different species are normal as DVMs for single species. In this presentation we extend the concept of supernormal DVMs to the case of multicomponent mixtures and introduce it for polyatomic molecules. By polyatomic molecules we mean here that each molecule has one of a finite number of different internal energies, which can change, or not, during a collision. We will present some general algorithms for constructing such models, but also give some concrete examples of such constructions. The two different approaches above can be combined to obtain multicomponent mixtures with a finite number of different internal energies, and then be extended in a natural way to chemical reactions. The DVMs are constructed in such a way that we for the shock-wave problem obtain similar structures as for the classical discrete Boltzmann equation (DBE) for one species, and therefore will be able to apply previously obtained results for the DBE. In fact the DBE becomes a system of ordinary differential equations (dynamical system) and the shock profiles can be seen as heteroclinic orbits connecting two singular points (Maxwellians). The previous results for the DBE then give us the existence of shock profiles for shock speeds close to a typical speed

  9. A novel Whole Air Sample Profiler (WASP) for the quantification of volatile organic compounds in the boundary layer

    SciTech Connect

    Mak, J. E.; Su, L.; Guenther, Alex B.; Karl, Thomas G.

    2013-10-16

    The emission and fate of reactive VOCs is of inherent interest to those studying chemical biosphere-atmosphere interactions. In-canopy VOC observations are obtainable using tower-based samplers, but the lack of suitable sampling systems for the full boundary 5 layer has limited the data characterizing the vertical structure of such gases above the canopy height and still in the boundary layer. This is the important region where many reactive VOCs are oxidized or otherwise removed. Here we describe an airborne sampling system designed to collect a vertical profile of air into a 3/800 OD tube 150m in length. The inlet ram air pressure is used to flow sampled air through the 10 tube, which results in a varying flow rate based on aircraft speed and altitude. Since aircraft velocity decreases during ascent, it is necessary to account for the variable flow rate into the tube. This is accomplished using a reference gas that is pulsed into the air stream so that the precise altitude of the collected air can be reconstructed post-collection. The pulsed injections are also used to determine any significant effect 15 from diffusion/mixing within the sampling tube, either during collection or subsequent extraction for gas analysis. This system has been successfully deployed, and we show some measured vertical profiles of isoprene and its oxidation products methacrolein and methyl vinyl ketone from a mixed canopy near Columbia, Missouri.

  10. Predicting the liquefaction phenomena from shear velocity profiling: Empirical approach to 6.3 Mw, May 2006 Yogyakarta earthquake

    SciTech Connect

    Hartantyo, Eddy; Brotopuspito, Kirbani S.; Sismanto; Waluyo

    2015-04-24

    The liquefactions phenomena have been reported after a shocking 6.5Mw earthquake hit Yogyakarta province in the morning at 27 May 2006. Several researchers have reported the damage, casualties, and soil failure due to the quake, including the mapping and analyzing the liquefaction phenomena. Most of them based on SPT test. The study try to draw the liquefaction susceptibility by means the shear velocity profiling using modified Multichannel Analysis of Surface Waves (MASW). This paper is a preliminary report by using only several measured MASW points. The study built 8-channel seismic data logger with 4.5 Hz geophones for this purpose. Several different offsets used to record the high and low frequencies of surface waves. The phase-velocity diagrams were stacked in the frequency domain rather than in time domain, for a clearer and easier dispersion curve picking. All codes are implementing in Matlab. From these procedures, shear velocity profiling was collected beneath each geophone’s spread. By mapping the minimum depth of shallow water table, calculating PGA with soil classification, using empirical formula for saturated soil weight from shear velocity profile, and calculating CRR and CSR at every depth, the liquefaction characteristic can be identify in every layer. From several acquired data, a liquefiable potential at some depth below water table was obtained.

  11. Predicting the liquefaction phenomena from shear velocity profiling: Empirical approach to 6.3 Mw, May 2006 Yogyakarta earthquake

    NASA Astrophysics Data System (ADS)

    Hartantyo, Eddy; Brotopuspito, Kirbani S.; Sismanto, Waluyo

    2015-04-01

    The liquefactions phenomena have been reported after a shocking 6.5Mw earthquake hit Yogyakarta province in the morning at 27 May 2006. Several researchers have reported the damage, casualties, and soil failure due to the quake, including the mapping and analyzing the liquefaction phenomena. Most of them based on SPT test. The study try to draw the liquefaction susceptibility by means the shear velocity profiling using modified Multichannel Analysis of Surface Waves (MASW). This paper is a preliminary report by using only several measured MASW points. The study built 8-channel seismic data logger with 4.5 Hz geophones for this purpose. Several different offsets used to record the high and low frequencies of surface waves. The phase-velocity diagrams were stacked in the frequency domain rather than in time domain, for a clearer and easier dispersion curve picking. All codes are implementing in Matlab. From these procedures, shear velocity profiling was collected beneath each geophone's spread. By mapping the minimum depth of shallow water table, calculating PGA with soil classification, using empirical formula for saturated soil weight from shear velocity profile, and calculating CRR and CSR at every depth, the liquefaction characteristic can be identify in every layer. From several acquired data, a liquefiable potential at some depth below water table was obtained.

  12. Measurement of Gas and Liquid Velocities in an Air-Water Two-Phase Flow using Cross-Correlation of Signals from a Double Senor Hot-Film Probe

    SciTech Connect

    B. Gurau; P. Vassalo; K. Keller

    2002-02-19

    Local gas and liquid velocities are measured by cross-correlating signals from a double sensor hot-film anemometer probe in pure water flow and air water two-phase flow. The gas phase velocity measured in two-phase flow agrees with velocity data obtained using high-speed video to within +/-5%. A turbulent structure, present in the liquid phase, allows a correlation to be taken, which is consistent with the expected velocity profiles in pure liquid flow. This turbulent structure is also present in the liquid phase of a two-phase flow system. Therefore, a similar technique can be applied to measure the local liquid velocity in a two-phase system, when conditions permit.

  13. The Impact of Atmospheric InfraRed Sounder (AIRS) Profiles on Short-term Weather Forecasts

    NASA Technical Reports Server (NTRS)

    Chou, Shih-Hung; Zavodsky, Brad; Jedlovec, Gary J.; Lapenta, William

    2007-01-01

    The Atmospheric Infrared Sounder (AIRS), together with the Advanced Microwave Sounding Unit (AMSU), represents one of the most advanced spacebased atmospheric sounding systems. The combined AlRS/AMSU system provides radiance measurements used to retrieve temperature profiles with an accuracy of 1 K over 1 km layers under both clear and partly cloudy conditions, while the accuracy of the derived humidity profiles is 15% in 2 km layers. Critical to the successful use of AIRS profiles for weather and climate studies is the use of profile quality indicators and error estimates provided with each profile Aside form monitoring changes in Earth's climate, one of the objectives of AIRS is to provide sounding information of sufficient accuracy such that the assimilation of the new observations, especially in data sparse region, will lead to an improvement in weather forecasts. The purpose of this paper is to describe a procedure to optimally assimilate highresolution AIRS profile data in a regional analysis/forecast model. The paper will focus on the impact of AIRS profiles on a rapidly developing east coast storm and will also discuss preliminary results for a 30-day forecast period, simulating a quasi-operation environment. Temperature and moisture profiles were obtained from the prototype version 5.0 EOS science team retrieval algorithm which includes explicit error information for each profile. The error profile information was used to select the highest quality temperature and moisture data for every profile location and pressure level for assimilation into the ARPS Data Analysis System (ADAS). The AIRS-enhanced analyses were used as initial fields for the Weather Research and Forecast (WRF) system used by the SPORT project for regional weather forecast studies. The ADASWRF system will be run on CONUS domain with an emphasis on the east coast. The preliminary assessment of the impact of the AIRS profiles will focus on quality control issues associated with AIRS

  14. Raindrop size distribution and vertical velocity characteristics in the rainband of Hurricane Bolaven (2012) observed by a 1290 MHz wind profiler

    NASA Astrophysics Data System (ADS)

    Kim, Dong-Kyun; Lee, Dong-In

    2017-03-01

    Microphysics and vertical velocity characteristics between weak and strong rainband regions of Hurricane Bolaven were investigated primarily from 1290 MHz (UHF) wind profiler measurements on 27-28 August 2012. With a focus on regions with radar reflectivities greater than 30 dBZ below a melting level, raindrop size distributions (DSDs) and related rain parameters retrieved from profiler Doppler spectra were examined. Temporal variations in vertical structure and bright band from a widespread stratiform to a relatively narrow, intense rainband were examined as the rainbands move over the land in the southern coast of Korea. Based on vertical characteristics in radar reflectivity, Doppler velocity, and vertical air motion (w) profiles, the rainbands were classified into a stratiform (S) region with a strong bright band and mixed stratiform-convective (S-C) region with a weak or non-existent bright band. The retrieved w fields showed that updrafts were dominant in the mixed S-C region and downdrafts in the S region. More broad histograms in both radar reflectivity (Z) and mass-weighted mean diameter (Dm) were found in the S period. Compared to the Z distribution, rain rate (R) was more widely distributed in the mixed S-C region than in the S region. This is largely because R values were more variable in association with stronger updrafts in this region since they depend on fall velocities of raindrops. Higher R and smaller Dm mean values were analyzed within relatively strong updrafts in the mixed S-C period compared to those in the S period. Even when the w correction is applied, the mean Dm was still slightly smaller in the mixed S-C region, indicating that there is a relatively larger number of small drops than those in the S region.

  15. A robust post-processing method to determine skin friction in turbulent boundary layers from the velocity profile

    NASA Astrophysics Data System (ADS)

    Rodríguez-López, Eduardo; Bruce, Paul J. K.; Buxton, Oliver R. H.

    2015-04-01

    The present paper describes a method to extrapolate the mean wall shear stress, , and the accurate relative position of a velocity probe with respect to the wall, , from an experimentally measured mean velocity profile in a turbulent boundary layer. Validation is made between experimental and direct numerical simulation data of turbulent boundary layer flows with independent measurement of the shear stress. The set of parameters which minimize the residual error with respect to the canonical description of the boundary layer profile is taken as the solution. Several methods are compared, testing different descriptions of the canonical mean velocity profile (with and without overshoot over the logarithmic law) and different definitions of the residual function of the optimization. The von Kármán constant is used as a parameter of the fitting process in order to avoid any hypothesis regarding its value that may be affected by different initial or boundary conditions of the flow. Results show that the best method provides an accuracy of for the estimation of the friction velocity and for the position of the wall. The robustness of the method is tested including unconverged near-wall measurements, pressure gradient, and reduced number of points; the importance of the location of the first point is also tested, and it is shown that the method presents a high robustness even in highly distorted flows, keeping the aforementioned accuracies if one acquires at least one data point in . The wake component and the thickness of the boundary layer are also simultaneously extrapolated from the mean velocity profile. This results in the first study, to the knowledge of the authors, where a five-parameter fitting is carried out without any assumption on the von Kármán constant and the limits of the logarithmic layer further from its existence.

  16. INVESTIGATING THE INFLUENCE OF RELATIVE HUMIDITY, AIR VELOCITY, AND AMPLIFICATION ON THE EMISSION RATES OF FUNGAL SPORES

    EPA Science Inventory

    The paper discusses the impact of relative humidity (RH), air velocity, and surface growth on the emission rates of fungal spores from the surface of contaminated material. Although the results show a complex interaction of factors, we have determined, for this limited data set,...

  17. Calculation and measurement of a neutral air flow velocity impacting a high voltage capacitor with asymmetrical electrodes

    SciTech Connect

    Malík, M. Primas, J.; Kopecký, V.; Svoboda, M.

    2014-01-15

    This paper deals with the effects surrounding phenomenon of a mechanical force generated on a high voltage asymmetrical capacitor (the so called Biefeld-Brown effect). A method to measure this force is described and a formula to calculate its value is also given. Based on this the authors derive a formula characterising the neutral air flow velocity impacting an asymmetrical capacitor connected to high voltage. This air flow under normal circumstances lessens the generated force. In the following part this velocity is measured using Particle Image Velocimetry measuring technique and the results of the theoretically calculated velocity and the experimentally measured value are compared. The authors found a good agreement between the results of both approaches.

  18. Determination of burst initiation location and tear propagation velocity during air burst testing of latex condoms

    NASA Astrophysics Data System (ADS)

    Davidhazy, Andrew

    1991-04-01

    The stress testing of latex condoms by an air burst procedure has been slow in gaining industry acceptance because questions have been raised regarding the influence of the test apparatus on the likelihood of breakage occurring where the condom is attached to the inflation device. It was desired to locate the areas at which the condoms tend to burst and thus corroborate or disprove these claims. Several factors associated with the bursting condom demanded the use of special instrumentation to detect arid study the burst initiation process. Microsecond duration electronic flashes were used for the initial stages of the investigation. Although the absolute point of initiation of a given burst could not be photographed, these high speed studies tend to indicate that the most likely place for high quality condoms to break is not where they are attached to the inflation device but at an intermediate area between the base and the tip of the condom. In addition, tear propagation characteristics and velocities were determined with a delayed-flash technique, a double-slit strip method and a rotating drum framing camera.

  19. Species and velocity visualization of unseeded heated air and combusting hydrogen jets using laser and flashlamp sources

    NASA Technical Reports Server (NTRS)

    Diskin, Glenn S.; Lempert, Walter R.; Miles, Richard B.

    1990-01-01

    Three techniques for the visualization of species and/or velocity in unseeded H2/air flames and heated air jets are described and preliminary image data are presented. The techniques described are: (1) simultaneous ArF laser imaging of H2, O2, and Rayleigh cross-section weighted density in an H2, O2, and Rayleigh cross-section weighted density in an H2/air flame; (2) ultraviolet flashlamp imaging of O2, OH, and Rayleigh cross-section weighted density in an H2/air flame; and (3) Raman Excitation plus Laser Induced Electronic Fluorescence velocimetry in heater air flows, up to static temperatures of 700 K. Application of these techniques, individually or in combination, should provide useful insight into mixing and reacting flows containing H2, O2, N2 and reaction intermediates such as OH.

  20. Wartime Distribution Operations: Roles of Focused Logistics, Velocity Management, Strategic Distribution Policy and Air Clearance Policy

    DTIC Science & Technology

    2004-03-19

    EFFECTIVE AND EFFICIENT ..................................................1 VELOCITY MANAGEMENT – DEFINITION AND HISTORY...achieve immediate improvements. This effort resulted in the Army adopting VM. VELOCITY MANAGEMENT – DEFINITION AND HISTORY Beginning in 1995, the Army

  1. Simultaneous measurement of temperature and velocity of air flow over 1000°C using two color phosphor thermometry

    NASA Astrophysics Data System (ADS)

    Fukuta, Masatoshi; Someya, Satoshi; Munakata, Tetsuo; LCS Team

    2016-11-01

    Thermal barrier coatings were applied to the gas turbines and the internal combustion engines for the high thermal efficiency. The evaluation and the improvement of coatings require to measure transient gaseous flow near the wall with coatings. An aim of this study is to combine a two color phosphor thermometry with the PIV to measure simultaneously temperature and velocity of the gas over 1000°C. The temperature and velocity distribution of an impinging jet of high temperature air was simultaneously visualized in experiments. The temperature was estimated from an intensity ratio of luminescent in different ranges of wavelength, 500 600 nm and 400 480 nm. Uncertainty of measured temperature was less than 10°C. Temperatures measured by the developed method and by thermocouples were agreed well. The measured velocity by the PIV with phosphor particles were also agreed well with the velocity measured by a Laser Doppler Velocimeter.

  2. Step-Wise Velocity of an Air Bubble Rising in a Vertical Tube Filled with a Liquid Dispersion of Nanoparticles.

    PubMed

    Cho, Heon Ki; Nikolov, Alex D; Wasan, Darsh T

    2017-03-21

    The motion of air bubbles in tubes filled with aqueous suspensions of nanoparticles (nanofluids) is of practical interest for bubble jets, lab-on-a-chip, and transporting media. Therefore, the focus of this study is the dynamics of air bubbles rising in a tube in a nanofluid. Many authors experimentally and analytically proposed that the velocity of rising air bubbles is constant for long air bubbles suspended in a vertical tube in common liquids (e.g. an aqueous glycerol solution) when the capillary number is larger than 10(-4). For the first time, we report here a systematic study of an air bubble rising in a vertical tube in a nanofluid (e.g. an aqueous silica dioxide nanoparticle suspension, nominal particle size, 19 nm). We varied the bubble length scaled by the diameter of the tubes (L/D), the concentration of the nanofluid (10 and 12.5 v %), and the tube diameter (0.45, 0.47, and 0.50 cm). The presence of the nanoparticles creates a significant change in the bubble velocity compared with the bubble rising in the common liquid with the same bulk viscosity. We observed a novel phenomenon of a step-wise increase in the air bubble rising velocity versus bubble length for small capillary numbers less than 10(-7). This step-wise velocity increase versus the bubble length was not observed in a common fluid. The step-wise velocity increase is attributed to the nanoparticle self-layering phenomenon in the film adjacent to the tube wall. To elucidate the role of the nanoparticle film self-layering on the bubble rising velocity, the effect of the capillary number, the tube diameter (e.g. the capillary pressure), and nanofilm viscosity are investigated. We propose a model that takes into consideration the nanoparticle layering in the film confinement to explain the step-wise velocity phenomenon versus the length of the bubble. The oscillatory film interaction energy isotherm is calculated and the Frenkel approach is used to estimate the film viscosity.

  3. Field monitoring of sprinting power-force-velocity profile before, during and after hamstring injury: two case reports.

    PubMed

    Mendiguchia, J; Edouard, P; Samozino, P; Brughelli, M; Cross, M; Ross, A; Gill, N; Morin, J B

    2016-01-01

    Very little is currently known about the effects of acute hamstring injury on over-ground sprinting mechanics. The aim of this research was to describe changes in power-force-velocity properties of sprinting in two injury case studies related to hamstring strain management: Case 1: during a repeated sprint task (10 sprints of 40 m) when an injury occurred (5th sprint) in a professional rugby player; and Case 2: prior to (8 days) and after (33 days) an acute hamstring injury in a professional soccer player. A sports radar system was used to measure instantaneous velocity-time data, from which individual mechanical profiles were derived using a recently validated method based on a macroscopic biomechanical model. Variables of interest included: maximum theoretical velocity (V0) and horizontal force (F(H0)), slope of the force-velocity (F-v) relationship, maximal power, and split times over 5 and 20 m. For Case 1, during the injury sprint (sprint 5), there was a clear change in the F-v profile with a 14% greater value of F(H0) (7.6-8.7 N/kg) and a 6% decrease in V0 (10.1 to 9.5 m/s). For Case 2, at return to sport, the F-v profile clearly changed with a 20.5% lower value of F(H0) (8.3 vs. 6.6 N/kg) and no change in V0. The results suggest that the capability to produce horizontal force at low speed (F(H0)) (i.e. first metres of the acceleration phase) is altered both before and after return to sport from a hamstring injury in these two elite athletes with little or no change of maximal velocity capabilities (V0), as evidenced in on-field conditions. Practitioners should consider regularly monitoring horizontal force production during sprint running both from a performance and injury prevention perspective.

  4. Partially obstructed channel: Contraction ratio effect on the flow hydrodynamic structure and prediction of the transversal mean velocity profile

    NASA Astrophysics Data System (ADS)

    Ben Meftah, M.; Mossa, M.

    2016-11-01

    In this manuscript, we focus on the study of flow structures in a channel partially obstructed by arrays of vertical, rigid, emergent, vegetation/cylinders. Special attention is given to understand the effect of the contraction ratio, defined as the ratio of the obstructed area width to the width of the unobstructed area, on the flow hydrodynamic structures and to analyze the transversal flow velocity profile at the obstructed-unobstructed interface. A large data set of transversal mean flow velocity profiles and turbulence characteristics is reported from experiments carried out in a laboratory flume. The flow velocities and turbulence intensities have been measured with a 3D Acoustic Doppler Velocimeter (ADV)-Vectrino manufactured by Nortek. It was observed that the arrays of emergent vegetation/cylinders strongly affect the flow structures, forming a shear layer immediately next to the obstructed-unobstructed interface, followed by an adjacent free-stream region of full velocity flow. The experimental results show that the contraction ratio significantly affects the flow hydrodynamic structure. Adaptation of the Prandtl's log-law modified by Nikuradse led to the determination of a characteristic hydrodynamic roughness height to define the array resistance to the flow. Moreover, an improved modified log-law predicting the representative transversal profile of the mean flow velocity, at the obstructed-unobstructed interface, is proposed. The benefit of this modified log-law is its easier practical applicability, i.e., it avoids the measurements of some sensitive turbulence parameters, in addition, the flow hydrodynamic variables forming it are predictable, using the initial hydraulic conditions.

  5. Remote measurement utilizing NASA's scanning laser Doppler systems. Volume 2: Laser Doppler dust devil velocity profile measurement program

    NASA Technical Reports Server (NTRS)

    Howle, R. E.; Krause, M. C.; Craven, C. E.; Gorzynski, E. J.; Edwards, B. B.

    1976-01-01

    The first detailed velocity profile data on thermally induced dust vortices are presented. These dust devils will be analyzed and studied to determine their flow fields and origin in an effort to correlate this phenomena with the generation and characteristics of tornadoes. A continuing effort to increase mankind's knowledge of vortex and other meteorological phenomena will hopefully allow the prediction of tornado occurrence, their path, and perhaps eventually even lead to some technique for their destruction.

  6. Major Upgrades to the AIRS Version-6 Water Vapor Profile Methodology

    NASA Technical Reports Server (NTRS)

    Susskind, Joel; Blaisdell, John; Iredell, Lena

    2015-01-01

    This research is a continuation of part of what was shown at the last AIRS Science Team Meeting and the AIRS 2015 NetMeeting. AIRS Version 6 was finalized in late 2012 and is now operational. Version 6 contained many significant improvements in retrieval methodology compared to Version 5. Version 6 retrieval methodology used for the water vapor profile q(p) and ozone profile O3(p) retrievals is basically unchanged from Version 5, or even from Version 4. Subsequent research has made significant improvements in both water vapor and O3 profiles compared to Version 6.

  7. Reexamination of the Classical View of how Drag-Reducing Polymer Solutions Modify the Mean Velocity Profile: Baseline Results

    NASA Astrophysics Data System (ADS)

    Farsiani, Yasaman; Baade, Jacquelyne; Elbing, Brian

    2016-11-01

    Recent numerical and experimental data have shown that the classical view of how drag-reducing polymer solutions modify the mean turbulent velocity profile is incorrect. The classical view is that the log-region is unmodified from the traditional law-of-the-wall for Newtonian fluids, though shifted outward. Thus the current study reexamines the modified velocity distribution and its dependence on flow and polymer properties. Based on previous work it is expected that the behavior will depend on the Reynolds number, Weissenberg number, ratio of solvent viscosity to the zero-shear viscosity, and the ratio between the coiled and fully extended polymer chain lengths. The long-term objective for this study includes a parametric study to assess the velocity profile sensitivity to each of these parameters. This study will be performed using a custom design water tunnel, which has a test section that is 1 m long with a 15.2 cm square cross section and a nominal speed range of 1 to 10 m/s. The current presentation focuses on baseline (non-polymeric) measurements of the velocity distribution using PIV, which will be used for comparison of the polymer modified results. Preliminary polymeric results will also be presented. This work was supported by NSF Grant 1604978.

  8. Novel measurement of blood velocity profile using translating-stage optical method and theoretical modeling based on non-Newtonian viscosity model

    NASA Astrophysics Data System (ADS)

    Kim, Chang-Beom; Lim, Jaeho; Hong, Hyobong; Kresh, J. Yasha; Wootton, David M.

    2015-07-01

    Detailed knowledge of the blood velocity distribution over the cross-sectional area of a microvessel is important for several reasons: (1) Information about the flow field velocity gradients can suggest an adequate description of blood flow. (2) Transport of blood components is determined by the velocity profiles and the concentration of the cells over the cross-sectional area. (3) The velocity profile is required to investigate volume flow rate as well as wall shear rate and shear stress which are important parameters in describing the interaction between blood cells and the vessel wall. The present study shows the accurate measurement of non-Newtonian blood velocity profiles at different shear rates in a microchannel using a novel translating-stage optical method. Newtonian fluid velocity profile has been well known to be a parabola, but blood is a non-Newtonian fluid which has a plug flow region at the centerline due to yield shear stress and has different viscosities depending on shear rates. The experimental results were compared at the same flow conditions with the theoretical flow equations derived from Casson non-Newtonian viscosity model in a rectangular capillary tube. And accurate wall shear rate and shear stress were estimated for different flow rates based on these velocity profiles. Also the velocity profiles were modeled and compared with parabolic profiles, concluding that the wall shear rates were at least 1.46-3.94 times higher than parabolic distribution for the same volume flow rate.

  9. Impact of Atmospheric Infrared Sounder (AIRS) Thermodynamic Profiles on Regional Weather Forecasting

    NASA Technical Reports Server (NTRS)

    Chou, Shih-Hung; Zavodsky, Bradley T.; Jedlovee, Gary J.

    2010-01-01

    In data sparse regions, remotely-sensed observations can be used to improve analyses and lead to better forecasts. One such source comes from the Atmospheric Infrared Sounder (AIRS), which together with the Advanced Microwave Sounding Unit (AMSU), provides temperature and moisture profiles with accuracy comparable to that of radiosondes. The purpose of this paper is to describe a procedure to assimilate AIRS thermodynamic profile data into a regional configuration of the Advanced Research Weather Research and Forecasting (WRF-ARW) model using its three-dimension variational (3DVAR) analysis component (WRF-Var). Quality indicators are used to select only the highest quality temperature and moisture profiles for assimilation in both clear and partly cloudy regions. Separate error characteristics for land and water profiles are also used in the assimilation process. Assimilation results indicate that AIRS profiles produce an analysis closer to in situ observations than the background field. Forecasts from a 37-day case study period in the winter of 2007 show that AIRS profile data can lead to improvements in 6-h cumulative precipitation forecasts due to instability added in the forecast soundings by the AIRS profiles. Additionally, in a convective heavy rainfall event from February 2007, assimilation of AIRS profiles produces a more unstable boundary layer resulting in enhanced updrafts in the model. These updrafts produce a squall line and precipitation totals that more closely reflect ground-based observations than a no AIRS control forecast. The location of available high-quality AIRS profiles ahead of approaching storm systems is found to be of paramount importance to the amount of impact the observations will have on the resulting forecasts.

  10. Carbon isotope evidence for the latitudinal distribution and wind speed dependence of the air-sea gas transfer velocity

    NASA Astrophysics Data System (ADS)

    Krakauer, Nir Y.; Randerson, James T.; Primeau, François W.; Gruber, Nicolas; Menemenlis, Dimitris

    2006-11-01

    The air-sea gas transfer velocity is an important determinant of the exchange of gases, including CO2, between the atmosphere and ocean, but the magnitude of the transfer velocity and what factors control it remains poorly known. Here, we use oceanic and atmospheric observations of 14C and 13C to constrain the global mean gas transfer velocity as well as the exponent of its wind speed dependence, utilizing the distinct signatures left by the air-sea exchange of 14CO2 and 13CO2. While the atmosphere and ocean inventories of 14CO2 and 13CO2 constrain the mean gas transfer velocity, the latitudinal pattern in the atmospheric and oceanic 14C and 13C distributions contain information about the wind speed dependence. We computed the uptake of bomb 14C by the ocean for different transfer velocity patterns using pulse response functions from an ocean general circulation model, and evaluated the match between the predicted bomb 14C concentrations and observationally based estimates for the 1970s-1990s. Using a wind speed climatology based on satellite measurements, we solved either for the best-fit global relationship between gas exchange and mean wind speed or for the mean gas transfer velocity over each of 11 ocean regions. We also compared the predicted consequences of different gas exchange relationships on the rate of change and interhemisphere gradient of 14C in atmospheric CO2 with tree-ring and atmospheric measurements. Our results suggest that globally, the dependence of the air-sea gas transfer velocity on wind speed is close to linear, with an exponent of 0.5 +/- 0.4, and that the global mean gas transfer velocity at a Schmidt number of 660 is 20 +/- 3 cm/hr, similar to the results of previous analyses. We find that the air-sea flux of 13C estimated from atmosphere and ocean observations also suggests a lower than quadratic dependence of gas exchange on wind speed.

  11. Decomposition Odour Profiling in the Air and Soil Surrounding Vertebrate Carrion

    PubMed Central

    2014-01-01

    Chemical profiling of decomposition odour is conducted in the environmental sciences to detect malodourous target sources in air, water or soil. More recently decomposition odour profiling has been employed in the forensic sciences to generate a profile of the volatile organic compounds (VOCs) produced by decomposed remains. The chemical profile of decomposition odour is still being debated with variations in the VOC profile attributed to the sample collection technique, method of chemical analysis, and environment in which decomposition occurred. To date, little consideration has been given to the partitioning of odour between different matrices and the impact this has on developing an accurate VOC profile. The purpose of this research was to investigate the decomposition odour profile surrounding vertebrate carrion to determine how VOCs partition between soil and air. Four pig carcasses (Sus scrofa domesticus L.) were placed on a soil surface to decompose naturally and their odour profile monitored over a period of two months. Corresponding control sites were also monitored to determine the VOC profile of the surrounding environment. Samples were collected from the soil below and the air (headspace) above the decomposed remains using sorbent tubes and analysed using gas chromatography-mass spectrometry. A total of 249 compounds were identified but only 58 compounds were common to both air and soil samples. This study has demonstrated that soil and air samples produce distinct subsets of VOCs that contribute to the overall decomposition odour. Sample collection from only one matrix will reduce the likelihood of detecting the complete spectrum of VOCs, which further confounds the issue of determining a complete and accurate decomposition odour profile. Confirmation of this profile will enhance the performance of cadaver-detection dogs that are tasked with detecting decomposition odour in both soil and air to locate victim remains. PMID:24740412

  12. Decomposition odour profiling in the air and soil surrounding vertebrate carrion.

    PubMed

    Forbes, Shari L; Perrault, Katelynn A

    2014-01-01

    Chemical profiling of decomposition odour is conducted in the environmental sciences to detect malodourous target sources in air, water or soil. More recently decomposition odour profiling has been employed in the forensic sciences to generate a profile of the volatile organic compounds (VOCs) produced by decomposed remains. The chemical profile of decomposition odour is still being debated with variations in the VOC profile attributed to the sample collection technique, method of chemical analysis, and environment in which decomposition occurred. To date, little consideration has been given to the partitioning of odour between different matrices and the impact this has on developing an accurate VOC profile. The purpose of this research was to investigate the decomposition odour profile surrounding vertebrate carrion to determine how VOCs partition between soil and air. Four pig carcasses (Sus scrofa domesticus L.) were placed on a soil surface to decompose naturally and their odour profile monitored over a period of two months. Corresponding control sites were also monitored to determine the VOC profile of the surrounding environment. Samples were collected from the soil below and the air (headspace) above the decomposed remains using sorbent tubes and analysed using gas chromatography-mass spectrometry. A total of 249 compounds were identified but only 58 compounds were common to both air and soil samples. This study has demonstrated that soil and air samples produce distinct subsets of VOCs that contribute to the overall decomposition odour. Sample collection from only one matrix will reduce the likelihood of detecting the complete spectrum of VOCs, which further confounds the issue of determining a complete and accurate decomposition odour profile. Confirmation of this profile will enhance the performance of cadaver-detection dogs that are tasked with detecting decomposition odour in both soil and air to locate victim remains.

  13. In vitro confocal micro-PIV measurements of blood flow in a square microchannel: the effect of the haematocrit on instantaneous velocity profiles.

    PubMed

    Lima, Rui; Wada, Shigeo; Takeda, Motohiro; Tsubota, Ken-ichi; Yamaguchi, Takami

    2007-01-01

    A confocal microparticle image velocimetry (micro-PIV) system was used to obtain detailed information on the velocity profiles for the flow of pure water (PW) and in vitro blood (haematocrit up to 17%) in a 100-microm-square microchannel. All the measurements were made in the middle plane of the microchannel at a constant flow rate and low Reynolds number (Re=0.025). The averaged ensemble velocity profiles were found to be markedly parabolic for all the working fluids studied. When comparing the instantaneous velocity profiles of the three fluids, our results indicated that the profile shape depended on the haematocrit. Our confocal micro-PIV measurements demonstrate that the root mean square (RMS) values increase with the haematocrit implying that it is important to consider the information provided by the instantaneous velocity fields, even at low Re. The present study also examines the potential effect of the RBCs on the accuracy of the instantaneous velocity measurements.

  14. Building America Top Innovations 2013 Profile – High-Efficiency Window Air Conditioners

    SciTech Connect

    none,

    2013-09-01

    This Top Innovation profile explains how comprehensive performance testing by the National Renewable Energy Laboratory led to simple, affordable methods that homeowners could employ for increasing the energy efficiency of window air conditioners.

  15. Application of 50 MHz doppler radar wind profiler to launch operations at Kennedy Space Center and Cape Canaveral Air Station

    NASA Technical Reports Server (NTRS)

    Schumann, Robin S.; Taylor, Gregory E.; Smith, Steve A.; Wilfong, Timothy L.

    1994-01-01

    This paper presents a case study where a significant wind shift, not detected by jimspheres, was detected by the 50 MHz DRWP (Doppler Radar Wind Profiler) and evaluated to be acceptable prior to the launch of a Shuttle. This case study illustrates the importance of frequent upper air wind measurements for detecting significant rapidly changing features as well as for providing confidence that the features really exist and are not due to instrumentation error. Had the release of the jimsphere been timed such that it would have detected the entire wind shift, there would not have been sufficient time to release another jimsphere to confirm the existence of the feature prior to the scheduled launch. We found that using a temporal median filter on the one minute spectral estimates coupled with a constraining window about a first guess velocity effectively removes nearly all spurious signals from the velocity profile generated by NASA's 50 MHz DRWP while boosting the temporal resolution to as high as one profile every 3 minutes. The higher temporal resolution of the 50 MHz DRWP using the signal processing algorithm described in this paper ensures the detection of rapidly changing features as well as provides the confidence that the features are genuine. Further benefit is gained when the profiles generated by the DRWP are examined in relation to the profiles measured by jimspheres and/or rawinsondes. The redundancy offered by using two independent measurements can dispel or confirm any suspicion regarding instrumentation error or malfunction and wind profiles can be examined in light of their respective instruments' strengths and weaknesses.

  16. Performance of a Compression-ignition Engine with a Precombustion Chamber Having High-Velocity Air Flow

    NASA Technical Reports Server (NTRS)

    Spanogle, J A; Moore, C S

    1931-01-01

    Presented here are the results of performance tests made with a single-cylinder, four stroke cycle, compression-ignition engine. These tests were made on a precombustion chamber type of cylinder head designed to have air velocity and tangential air flow in both the chamber and cylinder. The performance was investigated for variable load and engine speed, type of fuel spray, valve opening pressure, injection period and, for the spherical chamber, position of the injection spray relative to the air flow. The pressure variations between the pear-shaped precombustion chamber and the cylinder for motoring and full load conditions were determined with a Farnboro electric indicator. The combustion chamber designs tested gave good mixing of a single compact fuel spray with the air, but did not control the ensuing combustion sufficiently. Relative to each other, the velocity of air flow was too high, the spray dispersion by injection too great, and the metering effect of the cylinder head passage insufficient. The correct relation of these factors is of the utmost importance for engine performance.

  17. Comparisons of Crosswind Velocity Profile Estimates Used in Fast-Time Wake Vortex Prediction Models

    NASA Technical Reports Server (NTRS)

    Pruis, Mathew J.; Delisi, Donald P.; Ahmad, Nashat N.

    2011-01-01

    Five methods for estimating crosswind profiles used in fast-time wake vortex prediction models are compared in this study. Previous investigations have shown that temporal and spatial variations in the crosswind vertical profile have a large impact on the transport and time evolution of the trailing vortex pair. The most important crosswind parameters are the magnitude of the crosswind and the gradient in the crosswind shear. It is known that pulsed and continuous wave lidar measurements can provide good estimates of the wind profile in the vicinity of airports. In this study comparisons are made between estimates of the crosswind profiles from a priori information on the trajectory of the vortex pair as well as crosswind profiles derived from different sensors and a regional numerical weather prediction model.

  18. Group-phase Velocity Difference and THz Oscillation of the Nonlinear Refractive Index in Air: Particle-like Solutions

    SciTech Connect

    Kovachev, L. M.

    2009-10-29

    We present an analytical approach to the theory of optical pulses with superbroad spectrum propagated in air. The corresponding modified amplitude envelope equation admits oscillated with terahertz frequency nonlinear term The fluctuation is due to the group and phase velocity difference. In the partial case of femtosecond pulses with power, little above the critical for self-focusing, exact (3+1)D particle-like solution is found.

  19. Anomalous high-velocity outbursts ejected from the surface of tungsten microdroplets in a flow of argon-air plasma

    NASA Astrophysics Data System (ADS)

    Gulyaev, I. P.; Dolmatov, A. V.; Gulyaev, P. Yu; Iordan, V. I.; Kharlamov, M. Yu; Krivtsun, I. V.

    2016-02-01

    For the first time, a phenomenon of high-velocity outbursts ejected from the surface of liquid tungsten microparticles in a flow of argon-air plasma under atmospheric pressure was observed. As tungsten particles sized 50 to 200 μm moved in a plasma flow, stratified radiating spheres up to 9 mm in diameter formed around such particles. The spheres were sources of high-velocity outbursts whose ejection direction coincided with the direction of the plasma flow. The velocity of the anomalous outbursts amounted to 3-20 km/s. In the outburst images, the distribution of glow intensity along outburst tracks exhibited a wavy decaying behavior with a wavelength of 5-15 mm. Possible physical factors that could be the cause of the phenomenon are discussed.

  20. Influence of current velocity and wind speed on air-water gas exchange in a mangrove estuary

    NASA Astrophysics Data System (ADS)

    Ho, David T.; Coffineau, Nathalie; Hickman, Benjamin; Chow, Nicholas; Koffman, Tobias; Schlosser, Peter

    2016-04-01

    Knowledge of air-water gas transfer velocities and water residence times is necessary to study the fate of mangrove derived carbon exported into surrounding estuaries and ultimately to determine carbon balances in mangrove ecosystems. For the first time, the 3He/SF6 dual tracer technique, which has been proven to be a powerful tool to determine gas transfer velocities in the ocean, is applied to Shark River, an estuary situated in the largest contiguous mangrove forest in North America. The mean gas transfer velocity was 3.3 ± 0.2 cm h-1 during the experiment, with a water residence time of 16.5 ± 2.0 days. We propose a gas exchange parameterization that takes into account the major sources of turbulence in the estuary (i.e., bottom generated shear and wind stress).

  1. Inertial waves and mean velocity profiles in a rotating pipe and a circular annulus with axial flow.

    PubMed

    Yang, Yantao; Ostilla-Mónico, Rodolfo; Wu, Jiezhi; Orlandi, Paolo

    2015-01-01

    In this paper we solve the inviscid inertial wave solutions in a circular pipe or annulus rotating constantly about its axis with moderate angular speed. The solutions are constructed by the so-called helical wave functions. We reveal that the mean velocity profiles must satisfy certain conditions to accommodate the inertial waves at the bulk region away from boundary. These conditions require the axial and azimuthal components of the mean velocity to take the shapes of the zeroth and first order Bessel functions of the first kind, respectively. The theory is then verified by data obtained from direct numerical simulations for both rotating pipe and circular annulus, and excellent agreement is found between theory and numerical results. Large scale vortex clusters are found in the bulk region where the mean velocity profiles match the theoretical predictions. The success of the theory in rotating pipe, circular annulus, and streamwise rotating channel suggests that such inertial waves are quite common in wall bounded flow with background rotation.

  2. A Universal Velocity Dispersion Profile for Pressure Supported Systems: Evidence for MONDian Gravity across Seven Orders of Magnitude in Mass

    NASA Astrophysics Data System (ADS)

    Durazo, R.; Hernandez, X.; Cervantes Sodi, B.; Sánchez, S. F.

    2017-03-01

    For any MONDian extended theory of gravity where the rotation curves of spiral galaxies are explained through a change in physics rather than the hypothesis of dark matter, a generic dynamical behavior is expected for pressure supported systems: an outer flattening of the velocity dispersion profile occurring at a characteristic radius, where both the amplitude of this flat velocity dispersion and the radius at which it appears are predicted to show distinct scalings with the total mass of the system. By carefully analyzing the dynamics of globular clusters and elliptical galaxies, we are able to significantly extend the astronomical diversity of objects in which MONDian gravity has been tested, from spiral galaxies to the much larger mass range covered by pressure supported systems. We show that a universal projected velocity dispersion profile accurately describes various classes of pressure supported systems, and further, that the expectations of extended gravity are met across seven orders of magnitude in mass. These observed scalings are not expected under dark matter cosmology, and would require particular explanations tuned at the scales of each distinct astrophysical system.

  3. Combustion Velocity of Benzine-Benzol-Air Mixtures in High-Speed Internal-Combustion Engines

    NASA Technical Reports Server (NTRS)

    Schnauffer, Kurt

    1932-01-01

    The present paper describes a device whereby rapid flame movement within an internal-combustion engine cylinder may be recorded and determined. By the aid of a simple cylindrical contact and an oscillograph the rate of combustion within the cylinder of an airplane engine during its normal operation may be measured for gas intake velocities of from 30 to 35 m/s and for velocities within the cylinder of from 20 to 25 m/s. With it the influence of mixture ratios, of turbulence, of compression ratio and kind of fuel on combustion velocity may be determined. Besides the determination of the influence of the above factors on combustion velocity, the degree of turbulence may also be determined. As a unit of reference in estimating the degree of turbulence, the intake velocity of the charge is chosen.

  4. Building America Top Innovations 2014 Profile: HVAC Cabinet Air Leakage Test Method

    SciTech Connect

    none,

    2014-11-01

    This 2014 Top Innovation profile describes Building America-funded research by teams and national laboratories that resulted in the development of an ASHRAE standard and a standardized testing method for testing the air leakage of HVAC air handlers and furnace cabinets and has spurred equipment manufacturers to tighten the cabinets they use for residential HVAC systems.

  5. Evaluation of the Impact of AIRS Radiance and Profile Data Assimilation in Partly Cloudy Regions

    NASA Technical Reports Server (NTRS)

    Zavodsky, Bradley; Srikishen, Jayanthi; Jedlovec, Gary

    2013-01-01

    Improvements to global and regional numerical weather prediction have been demonstrated through assimilation of data from NASA s Atmospheric Infrared Sounder (AIRS). Current operational data assimilation systems use AIRS radiances, but impact on regional forecasts has been much smaller than for global forecasts. Retrieved profiles from AIRS contain much of the information that is contained in the radiances and may be able to reveal reasons for this reduced impact. Assimilating AIRS retrieved profiles in an identical analysis configuration to the radiances, tracking the quantity and quality of the assimilated data in each technique, and examining analysis increments and forecast impact from each data type can yield clues as to the reasons for the reduced impact. By doing this with regional scale models individual synoptic features (and the impact of AIRS on these features) can be more easily tracked. This project examines the assimilation of hyperspectral sounder data used in operational numerical weather prediction by comparing operational techniques used for AIRS radiances and research techniques used for AIRS retrieved profiles. Parallel versions of a configuration of the Weather Research and Forecasting (WRF) model with Gridpoint Statistical Interpolation (GSI) are run to examine the impact AIRS radiances and retrieved profiles. Statistical evaluation of a long-term series of forecast runs will be compared along with preliminary results of in-depth investigations for select case comparing the analysis increments in partly cloudy regions and short-term forecast impacts.

  6. Comparison of P- and S-wave velocity profiles obtained from surface seismic refraction/reflection and downhole data

    USGS Publications Warehouse

    Williams, R.A.; Stephenson, W.J.; Odum, J.K.

    2003-01-01

    High-resolution seismic-reflection/refraction data were acquired on the ground surface at six locations to compare with near-surface seismic-velocity downhole measurements. Measurement sites were in Seattle, WA, the San Francisco Bay Area, CA, and the San Fernando Valley, CA. We quantitatively compared the data in terms of the average shear-wave velocity to 30-m depth (Vs30), and by the ratio of the relative site amplification produced by the velocity profiles of each data type over a specified set of quarter-wavelength frequencies. In terms of Vs30, similar values were determined from the two methods. There is <15% difference at four of the six sites. The Vs30 values at the other two sites differ by 21% and 48%. The relative site amplification factors differ generally by less than 10% for both P- and S-wave velocities. We also found that S-wave reflections and first-arrival phase delays are essential for identifying velocity inversions. The results suggest that seismic reflection/refraction data are a fast, non-invasive, and less expensive alternative to downhole data for determining Vs30. In addition, we emphasize that some P- and S-wave reflection travel times can directly indicate the frequencies of potentially damaging earthquake site resonances. A strong correlation between the simple S-wave first-arrival travel time/apparent velocity on the ground surface at 100 m offset from the seismic source and the Vs30 value for that site is an additional unique feature of the reflection/refraction data that could greatly simplify Vs30 determinations. ?? 2003 Elsevier Science B.V. All rights reserved.

  7. Impact of Atmospheric Infrared Sounder (AIRS) Thermodynamic Profiles on Regional Precipitation Forecasting

    NASA Technical Reports Server (NTRS)

    Chou, S.-H.; Zavodsky, B. T.; Jedloved, G. J.

    2010-01-01

    In data sparse regions, remotely-sensed observations can be used to improve analyses and lead to better forecasts. One such source comes from the Atmospheric Infrared Sounder (AIRS), which together with the Advanced Microwave Sounding Unit (AMSU), provides temperature and moisture profiles in clear and cloudy regions with accuracy which approaches that of radiosondes. The purpose of this paper is to describe an approach to assimilate AIRS thermodynamic profile data into a regional configuration of the Advanced Research WRF (ARW) model using WRF-Var. Quality indicators are used to select only the highest quality temperature and moisture profiles for assimilation in clear and partly cloudy regions, and uncontaminated portions of retrievals above clouds in overcast regions. Separate error characteristics for land and water profiles are also used in the assimilation process. Assimilation results indicate that AIRS profiles produce an analysis closer to in situ observations than the background field. Forecasts from a 37-day case study period in the winter of 2007 show that AIRS profile data can lead to improvements in 6-h cumulative precipitation forecasts resulting from improved thermodynamic fields. Additionally, in a convective heavy rainfall event from February 2007, assimilation of AIRS profiles produces a more unstable boundary layer resulting in enhanced updrafts in the model. These updrafts produce a squall line and precipitation totals that more closely reflect ground-based observations than a no AIRS control forecast. The location of available high-quality AIRS profiles ahead of approaching storm systems is found to be of paramount importance to the amount of impact the observations will have on the resulting forecasts.

  8. Effects of velocity profile and inclination on dual-jet-induced pressures on a flat plate in a crosswind

    NASA Technical Reports Server (NTRS)

    Jakubowski, A. L.; Schetz, J. A.; Moore, C. L.; Joag, R.

    1985-01-01

    An experimental study was conducted to determine surface pressure distributions on a flat plate with dual subsonic, circular jets exhausting from the surface into a crossflow. The jets were arranged in both side-by-side and tandem configurations and were injected at 90 deg and 60 deg angles to the plate, with jet-to-crossflow velocity ratio of 2.2 and 4. The major objective of the study was to determine the effect of a nonuniform (vs uniform) jet velocity profile, simulating the exhaust of a turbo-fan engine. Nonuniform jets with a high-velocity outer annulus and a low-velocity core induced stronger negative pressure fields than uniform jets with the same mass flow rate. However, nondimensional lift losses (lift loss/jet thrust lift) due to such nonuniform jets were lower than lift losses due to uniform jets. Changing the injection angle from 90 deg to 60 deg resulted in moderate (for tandem jets) to significant (for side-by-side jets) increases in the induced negative pressures, even though the surface area influenced by the jets tended to reduce as the angle decreased. Jets arranged in the side-by-side configuration led to significant jet-induced lift losses exceeding, in some cases, lift losses reported for single jets.

  9. Cylindrical Couette flow of a rarefied gas: Effect of a boundary condition on the inverted velocity profile

    NASA Astrophysics Data System (ADS)

    Kosuge, Shingo

    2015-07-01

    The cylindrical Couette flow of a rarefied gas between a rotating inner cylinder and a stationary outer cylinder is investigated under the following two kinds of kinetic boundary conditions. One is the modified Maxwell-type boundary condition proposed by Dadzie and Méolans [J. Math. Phys. 45, 1804 (2004), 10.1063/1.1690491] and the other is the Cercignani-Lampis condition, both of which have separate accommodation coefficients associated with the molecular velocity component normal to the boundary and with the tangential component. An asymptotic analysis of the Boltzmann equation for small Knudsen numbers and a numerical analysis of the Bhatnagar-Gross-Krook model equation for a wide range of the Knudsen number are performed to clarify the effect of each accommodation coefficient as well as of the boundary condition itself on the behavior of the gas, especially on the flow-velocity profile. As a result, the velocity-slip and temperature-jump conditions corresponding to the above kinetic boundary conditions are derived, which are necessary for the fluid-dynamic description of the problem for small Knudsen numbers. The parameter range for the onset of the velocity inversion phenomenon, which is related mainly to the decrease in the tangential momentum accommodation, is also obtained.

  10. Improving the accuracy of vehicle emissions profiles for urban transportation greenhouse gas and air pollution inventories.

    PubMed

    Reyna, Janet L; Chester, Mikhail V; Ahn, Soyoung; Fraser, Andrew M

    2015-01-06

    Metropolitan greenhouse gas and air emissions inventories can better account for the variability in vehicle movement, fleet composition, and infrastructure that exists within and between regions, to develop more accurate information for environmental goals. With emerging access to high quality data, new methods are needed for informing transportation emissions assessment practitioners of the relevant vehicle and infrastructure characteristics that should be prioritized in modeling to improve the accuracy of inventories. The sensitivity of light and heavy-duty vehicle greenhouse gas (GHG) and conventional air pollutant (CAP) emissions to speed, weight, age, and roadway gradient are examined with second-by-second velocity profiles on freeway and arterial roads under free-flow and congestion scenarios. By creating upper and lower bounds for each factor, the potential variability which could exist in transportation emissions assessments is estimated. When comparing the effects of changes in these characteristics across U.S. cities against average characteristics of the U.S. fleet and infrastructure, significant variability in emissions is found to exist. GHGs from light-duty vehicles could vary by -2%-11% and CAP by -47%-228% when compared to the baseline. For heavy-duty vehicles, the variability is -21%-55% and -32%-174%, respectively. The results show that cities should more aggressively pursue the integration of emerging big data into regional transportation emissions modeling, and the integration of these data is likely to impact GHG and CAP inventories and how aggressively policies should be implemented to meet reductions. A web-tool is developed to aide cities in improving emissions uncertainty.

  11. Linear relation between H I circular velocity and stellar velocity dispersion in early-type galaxies, and slope of the density profiles

    NASA Astrophysics Data System (ADS)

    Serra, Paolo; Oosterloo, Tom; Cappellari, Michele; den Heijer, Milan; Józsa, Gyula I. G.

    2016-08-01

    We report a tight linear relation between the H I circular velocity measured at 6 Re and the stellar velocity dispersion measured within 1 Re for a sample of 16 early-type galaxies with stellar mass between 1010 and 1011 M⊙. The key difference from previous studies is that we only use spatially resolved vcirc(H I) measurements obtained at large radius for a sizeable sample of objects. We can therefore link a kinematical tracer of the gravitational potential in the dark-matter dominated outer regions of galaxies with one in the inner regions, where baryons control the distribution of mass. We find that vcirc(H I)= 1.33 σe with an observed scatter of just 12 per cent. This indicates a strong coupling between luminous and dark matter from the inner- to the outer regions of early-type galaxies, analogous to the situation in spirals and dwarf irregulars. The vcirc(H I)-σe relation is shallower than those based on vcirc measurements obtained from stellar kinematics and modelling at smaller radius, implying that vcirc declines with radius - as in bulge-dominated spirals. Indeed, the value of vcirc(H I) is typically 25 per cent lower than the maximum vcirc derived at ˜0.2 Re from dynamical models. Under the assumption of power-law total density profiles ρ ∝ r-γ, our data imply an average logarithmic slope <γ> = 2.18 ± 0.03 across the sample, with a scatter of 0.11 around this value. The average slope and scatter agree with recent results obtained from stellar kinematics alone for a different sample of early-type galaxies.

  12. Tunable diode laser absorption sensor for temperature and velocity measurements of O2 in air flows

    NASA Technical Reports Server (NTRS)

    Philippe, L. C.; Hanson, R. K.

    1991-01-01

    A fast and nonintrusive velocity and temperature diagnostic based on oxygen absorption is presented. The system uses a GaAlAs tunable diode laser, ramped and modulated in wavelength at high frequency. Detection is performed at twice the modulating frequency, leading to second harmonic absorption lineshapes. Velocity is inferred from the wavelength shift of the absorption line center due to the Doppler effect. Temperature is determined by comparing experimental and calculated lineshapes. Capabilities of the technique for studies of transient high-speed flows are demonstrated in shock tube experiments. Good agreement is obtained with predicted temperatures and velocities when pressure-induced shifts are accounted for.

  13. Increased Air Velocity Reduces Thermal and Cardiovascular Strain in Young and Older Males during Humid Exertional Heat Stress.

    PubMed

    Wright Beatty, Heather E; Hardcastle, Stephen G; Boulay, Pierre; Flouris, Andreas D; Kenny, Glen P

    2015-01-01

    Older adults have been reported to have a lower evaporative heat loss capacity than younger adults during exercise when full sweat evaporation is permitted. However, it is unclear how conditions of restricted evaporative and convective heat loss (i.e., high humidity, clothing insulation) alter heat stress. to the purpose of this study was to examine the heat stress responses of young and older males during and following exercise in a warm/humid environment under two different levels of air velocity. Ten young (YOUNG: 24±2 yr) and 10 older (OLDER: 59±3 yr) males, matched for body surface area performed 4×15-min cycling bouts (15-min rest) at a fixed rate of heat production (400 W) in warm/humid conditions (35°C, 60% relative humidity) under 0.5 (Low) and 3.0 (High) m·s(-1) air velocity while wearing work coveralls. Rectal (Tre) and mean skin (MTsk) temperatures, heart rate (HR), local sweat rate, % max skin blood flow (SkBF) (recovery only), and blood pressure (recovery only) were measured. High air velocity reduced core and skin temperatures (p < 0.05) equally in YOUNG and OLDER males (p > 0.05) but was more effective in reducing cardiovascular strain (absolute and % max HR; p < 0.05) in YOUNG males (p < 0.05). Greater increases in local dry heat loss responses (% max SkBF and cutaneous vascular conductance) were detected across time in OLDER than YOUNG males in both conditions (p < 0.05). Local dry heat loss responses and cardiovascular strain were attenuated during the High condition in YOUNG compared to OLDER (p < 0.05). High air velocity reduced the number of males surpassing the 38.0°C Tre threshold from 90% (Low) to 50% (High). Despite age-related local heat loss differences, YOUNG and OLDER males had similar levels of heat stress during intermittent exercise in warm and humid conditions while wearing work coveralls. Increased air velocity was effective in reducing heat stress equally, and cardiovascular strain to a greater extent, in YOUNG and OLDER

  14. Relation between symptoms and profiles of coronary artery blood flow velocities in patients with aortic valve stenosis: a study using transoesophageal Doppler echocardiography.

    PubMed Central

    Omran, H.; Fehske, W.; Rabahieh, R.; Hagendorff, A.; Lüderitz, B.

    1996-01-01

    OBJECTIVE: To analyse profiles of coronary artery flow velocity at rest in patients with aortic stenosis and to determine whether changes of the coronary artery flow velocities are related to symptoms in patients with aortic stenosis. DESIGN: A prospective study investigating the significance of aortic valve area, pressure gradient across the aortic valve, systolic left ventricular wall stress index, ejection fraction, and left ventricular mass index in the coronary flow velocity profile of aortic stenosis; and comparing flow velocity profiles between symptomatic and asymptomatic patients with aortic stenosis using transoesophageal Doppler echocardiography to obtain coronary artery flow velocities of the left anterior descending coronary artery. SETTING: Tertiary referral cardiac centre. PATIENTS: Fifty eight patients with aortic stenosis and 15 controls with normal coronary arteries. RESULTS: Adequate recordings of the profile of coronary artery flow velocities were obtained in 46 patients (79%). Left ventricular wall stress was the only significant haemodynamic variable for determining peak systolic velocity (r = -0.83, F = 88.5, P < 0.001). The pressure gradient across the aortic valve was the only contributor for explaining peak diastolic velocity (r = 0.56, F = 20.9, P < 0.001). Controls and asymptomatic patients with aortic stenosis (n = 12) did not differ for peak systolic velocity [32.8 (SEM 9.7) v 27.0 (8.7) cm/s, NS] and peak diastolic velocity [58.3 (18.7) v 61.9 (13.5) cm/s, NS]. In contrast, patients with angina (n = 12) or syncope (n = 8) had lower peak systolic velocities and higher peak diastolic velocities than asymptomatic patients (P < 0.01). Peak systolic and diastolic velocities were -7.7 (22.5) cm/s and 81.7 (17.6) cm/s for patients with angina, and -19.5 (22.3) cm/s and 94.0 (20.9) cm/s for patients with syncope. Asymptomatic patients and patients with dyspnoea (n = 14) did not differ. CONCLUSIONS: Increased pressure gradient across the

  15. Aerodynamic and acoustic investigation of inverted velocity profile coannular exhaust nozzle models and development of aerodynamic and acoustic prediction procedures

    NASA Technical Reports Server (NTRS)

    Larson, R. S.; Nelson, D. P.; Stevens, B. S.

    1979-01-01

    Five co-annular nozzle models, covering a systematic variation of nozzle geometry, were tested statically over a range of exhaust conditions including inverted velocity profile (IVP) (fan to primary stream velocity ratio 1) and non IVP profiles. Fan nozzle pressure ratio (FNPR) was varied from 1.3 to 4.1 at primary nozzle pressure ratios (PNPR) of 1.53 and 2.0. Fan stream temperatures of 700 K (1260 deg R) and 1089 K(1960 deg R) were tested with primary stream temperatures of 700 K (1260 deg R), 811 K (1460 deg R), and 1089 K (1960 deg R). At fan and primary stream velocities of 610 and 427 m/sec (2000 and 1400 ft/sec), respectively, increasing fan radius ratio from 0.69 to 0.83 reduced peak perceived noise level (PNL) 3 dB, and an increase in primary radius ratio from 0 to 0.81 (fan radius ratio constant at 0.83) reduced peak PNL an additional 1.0 dB. There were no noise reductions at a fan stream velocity of 853 m/sec (2800 ft/sec). Increasing fan radius ratio from 0.69 to 0.83 reduced nozzle thrust coefficient 1.2 to 1.5% at a PNPR of 1.53, and 1.7 to 2.0% at a PNPR of 2.0. The developed acoustic prediction procedure collapsed the existing data with standard deviation varying from + or - 8 dB to + or - 7 dB. The aerodynamic performance prediction procedure collapsed thrust coefficient measurements to within + or - .004 at a FNPR of 4.0 and a PNPR of 2.0.

  16. Threshold velocities for input of soil particles into the air by desert soils

    SciTech Connect

    Gillette, D.A.; Adams, J.; Endo, A.; Smith, D.; Kihl, R.

    1980-10-20

    Desert soils mostly from the Mojave Desert were tested for threshold friction velocity (the friction velocity above which soil erosion takes place) with an open-bottomed portable wind tunnel. Several geomorphological settings were chosen to be representative of much of the surface of the Mojave Desert, for example, playas, alluvial fans, and aeolian features. Variables which increase threshold velocity are decreasing proportion of sand, increasing size of dry aggregates of the soil, and increasing fraction of the soil mass larger than 1 mm. Threshold velocity increases with different types of soil surfaces in the following order: disturbed soils (except disturbed heavy clay soils), sand dunes, alluvial and aeolian sand deposits, disturbed playa soils, skirts of playas, playa centers, and desert pavement (alluvial deposits). 21 references, 5 figures, 6 tables.

  17. A pulsed wire probe for the measurement of velocity and flow direction in slowly moving air.

    PubMed

    Olson, D E; Parker, K H; Snyder, B

    1984-02-01

    This report describes the theory and operation of a pulsed-probe anemometer designed to measure steady three-dimensional velocity fields typical of pulmonary tracheo-bronchial airflows. Local velocities are determined by measuring the transport time and orientation of a thermal pulse initiated at an upstream wire and sensed at a downstream wire. The transport time is a reproducible function of velocity and the probe wire spacing, as verified by a theoretical model of convective heat transfer. When calibrated the anemometer yields measurements of velocity accurate to +/- 5 percent and resolves flow direction to within 1 deg at airspeeds greater than or equal to 10 cm/s. Spatial resolution is +/- 0.5 mm. Measured flow patterns typical of curved circular pipes are included as examples of its application.

  18. Threshold velocities for input of soil particles into the air by desert soils

    NASA Astrophysics Data System (ADS)

    Gillette, Dale A.; Adams, John; Endo, Albert; Smith, Dudley; Kihl, Rolf

    1980-10-01

    Desert soils mostly from the Mojave Desert were tested for threshold friction velocity (the friction velocity above which soil erosion takes place) with an open-bottomed portable wind tunnel. Several geomorphological settings were chosen to be representative of much of the surface of the Mojave Desert, for example, playas, alluvial fans, and aeolian features. Variables which increase threshold velocity are decreasing proportion of sand, increasing size of dry aggregates of the soil, and increasing fraction of the soil mass larger than 1 mm. Threshold velocity increases with different types of soil surfaces in the following order: distrubed soils (except disturbed heavy clay soils), sand dunes, alluvial and aeolian sand deposits, disturbed playa soils, skirts of playas, playa centers, and desert pavements (alluvial deposits).

  19. Measurements of the Air-flow Velocity in the Cylinder of an Airplane Engine

    NASA Technical Reports Server (NTRS)

    Wenger, Hermann

    1939-01-01

    The object of the present investigation is to determine the velocity in the BMW-VI cylinder of an externally driven single-cylinder test engine at high engine speeds using the hot-wire method of Ulsamer.

  20. A method for predicting the noise levels of coannular jets with inverted velocity profiles

    NASA Technical Reports Server (NTRS)

    Russell, J. W.

    1979-01-01

    A coannular jet was equated with a single stream equivalent jet with the same mass flow, energy, and thrust. The acoustic characteristics of the coannular jet were then related to the acoustic characteristics of the single jet. Forward flight effects were included by incorporating a forward exponent, a Doppler amplification factor, and a Strouhal frequency shift. Model test data, including 48 static cases and 22 wind tunnel cases, were used to evaluate the prediction method. For the static cases and the low forward velocity wind tunnel cases, the spectral mean square pressure correlation coefficients were generally greater than 90 percent, and the spectral sound pressure level standard deviation were generally less than 3 decibels. The correlation coefficient and the standard deviation were not affected by changes in equivalent jet velocity. Limitations of the prediction method are also presented.

  1. Work performed on velocity profiles in a hot jet by simplified RELIEF

    NASA Technical Reports Server (NTRS)

    Miles, Richard B.; Lempert, Walter R.

    1991-01-01

    The Raman Excitation + Laser Induced Electronic Fluorescence (RELIEF) velocity measurement method is based on vibrationally tagging oxygen molecules and observing their displacement after a short period of time. Two papers that discuss the use and implementation of the RELIEF technique are presented in this final report. Additionally, the end of the report contains a listing of the personnel involved and the reference documents used in the production of this final report.

  2. Relaxation of molecular velocities and spectral line profiles of astrophysical masers

    NASA Technical Reports Server (NTRS)

    Anderson, Nels; Watson, William D.

    1993-01-01

    The rates at which the velocities of water molecules relax to a Maxwellian distribution are calculated under conditions that are representative of those in astrophysical water masers. Populations are calculated as a function of velocity for the lowest 40 rotational energy levels of ortho-water in order to make a detailed determination of the velocity relaxation rate. Relaxation rates for the 22 GHz maser at H2 densities of 10 exp 9/cu cm are 2.0/s and 5.1/s for temperatures of 400 K and 1000 K, respectively. Under these and other conditions, as well as for other maser transitions, the relaxation rate far exceeds the loss rate - usually by more than a factor of 10. Thus maser lines can remain narrow up to intensities that are at least a factor of 10 greater than the saturation intensity, and to path lengths that are at least a factor of 10 greater than the path length at which saturation occurs. Relaxation is dominated by the effects of trapped infrared radiation, though elastic and inelastic collisions are also included in the calculations. These relaxation rates, together with the observed line breadths of the 22 GHz masers, provide limits on maser luminosities which indicate that the brightest 22 GHz masers are highly beamed, with solid angles smaller than 10 exp -5 to 10 exp -4 Sr.

  3. Retrieval of Raindrop Size Distribution, Vertical Air Velocity and Water Vapor Attenuation Using Dual-Wavelength Doppler Radar Observations

    NASA Technical Reports Server (NTRS)

    Heymsfield, Gerald M.; Tian, Lin; Li, Lihua; Srivastava, C.

    2005-01-01

    Two techniques for retrieving the slope and intercept parameters of an assumed exponential raindrop size distribution (RSD), vertical air velocity, and attenuation by precipitation and water vapor in light stratiform rain using observations by airborne, nadir looking dual-wavelength (X-band, 3.2 cm and W-band, 3.2 mm) radars are presented. In both techniques, the slope parameter of the RSD and the vertical air velocity are retrieved using only the mean Doppler velocities at the two wavelengths. In the first method, the intercept of the RSD is estimated from the observed reflectivity at the longer wavelength assuming no attenuation at that wavelength. The attenuation of the shorter wavelength radiation by precipitation and water vapor are retrieved using the observed reflectivity at the shorter wavelength. In the second technique, it is assumed that the longer wavelength suffers attenuation only in the melting band. Then, assuming a distribution of water vapor, the melting band attenuation at both wavelengths and the rain attenuation at the shorter wavelength are retrieved. Results of the retrievals are discussed and several physically meaningful results are presented.

  4. Effect of flow velocity and temperature on ignition characteristics in laser ignition of natural gas and air mixtures

    NASA Astrophysics Data System (ADS)

    Griffiths, J.; Riley, M. J. W.; Borman, A.; Dowding, C.; Kirk, A.; Bickerton, R.

    2015-03-01

    Laser induced spark ignition offers the potential for greater reliability and consistency in ignition of lean air/fuel mixtures. This increased reliability is essential for the application of gas turbines as primary or secondary reserve energy sources in smart grid systems, enabling the integration of renewable energy sources whose output is prone to fluctuation over time. This work details a study into the effect of flow velocity and temperature on minimum ignition energies in laser-induced spark ignition in an atmospheric combustion test rig, representative of a sub 15 MW industrial gas turbine (Siemens Industrial Turbomachinery Ltd., Lincoln, UK). Determination of minimum ignition energies required for a range of temperatures and flow velocities is essential for establishing an operating window in which laser-induced spark ignition can operate under realistic, engine-like start conditions. Ignition of a natural gas and air mixture at atmospheric pressure was conducted using a laser ignition system utilizing a Q-switched Nd:YAG laser source operating at 532 nm wavelength and 4 ns pulse length. Analysis of the influence of flow velocity and temperature on ignition characteristics is presented in terms of required photon flux density, a useful parameter to consider during the development laser ignition systems.

  5. Anthropometric profile, vertical jump, and throwing velocity in elite female handball players by playing positions.

    PubMed

    Vila, Helena; Manchado, Carmen; Rodriguez, Nuria; Abraldes, José Arturo; Alcaraz, Pedro Emilio; Ferragut, Carmen

    2012-08-01

    Women's handball is a sport, which has seen an accelerated development over the last decade. Although anthropometric and physical characteristics have been studied for male sports teams, in women's handball, studies are scarce. The aim of this study was twofold: first, to describe the anthropometric characteristics, throwing velocity, hand grip, and muscular power of the lower limbs in female handball players and second, to identify the possible differences in these parameters in terms of individual playing positions (center, back, wing, pivot, and goalkeeper). A total of 130 elite female Spanish handball players participated in the study (age 25.74 ± 4.84 years; playing experience 14.92 ± 4.88 years). Anthropometric assessment was performed for all the subjects following the International Society for the Advancement of Kinanthropometry protocols. Furthermore, all the subjects performed a vertical jump test (squat jump and countermovement jump). Hand grip and throwing velocity in several situations were also assessed. A 1-way analysis of variance and a Tukey post hoc test were used to study the differences among individual playing positions. Wings were less heavy, shorter, and showed a smaller arm span than did goalkeepers, backs and pivots (p ≤ 0.001). Additionally, pivots were heavier than centers. Backs and pivots exhibited higher muscular mass than did wings. Total players' somatotype was mesomorphy endomorphy (3.89-4.28-2.29). Centers showed higher throwing velocity levels than did wings in 9-m throws from just behind the line, with a goalkeeper. Backs exhibited higher hand-grip values than did wings. Statistical differences have been established between wings and other specific playing positions, especially with pivot and backs. Coaches can use this information to select players for the different specific positions.

  6. Velocity Profiles in a Long Inlet Duct Employing a Photon Correlating Laser Velocimeter Without Seeding

    DTIC Science & Technology

    1979-12-01

    probe or Pitot-tube into the flow field. F. As the speed or RPM of the engine was set at the two distinct RPM settings by the use of a tachometer , the...Catalano and the author utilized the equipment at the Flight Dynamics two foot wind tunnel. In thi3 application, the Laser Velocimeter System was used to...the same side of the wind tunnel. Although some difficulty wasI encountered in focusing and aligning the set-up, mean velocity and turbulence intensity

  7. Measuring centimeter-resolution air temperature profiles above land and water using fiber-optic Distributed Temperature Sensing

    NASA Astrophysics Data System (ADS)

    Sigmund, Armin; Pfister, Lena; Olesch, Johannes; Thomas, Christoph K.

    2016-04-01

    The precise determination of near-surface air temperature profiles is of special importance for the characterization of airflows (e.g. cold air) and the quantification of sensible heat fluxes according to the flux-gradient similarity approach. In contrast to conventional multi-sensor techniques, measuring temperature profiles using fiber-optic Distributed Temperature Sensing (DTS) provides thousands of measurements referenced to a single calibration standard at much reduced costs. The aim of this work was to enhance the vertical resolution of Raman scatter DTS measurements up to the centimeter-scale using a novel approach for atmospheric applications: the optical fiber was helically coiled around a meshed fabric. In addition to testing the new fiber geometry, we quantified the measurement uncertainty and demonstrated the benefits of the enhanced-resolution profiles. The fiber-optic cable was coiled around a hollow column consisting of white reinforcing fabric supported by plexiglass rings every meter. Data from two columns of this type were collected for 47 days to measure air temperature vertically over 3.0 and 5.1 m over a gently inclined meadow and over and in a small lake, respectively. Both profiles had a vertical resolution of 1 cm in the lower section near the surface and 5 cm in the upper section with an along-fiber instrument-specific averaging of 1.0 m and a temporal resolution of 30 s. Measurement uncertainties, especially from conduction between reinforcing fabric and fiber-optic cable, were estimated by modeling the fiber temperature via a detailed energy balance approach. Air temperature, wind velocity and radiation components were needed as input data and measured separately. The temperature profiles revealed valuable details, especially in the lowest 1 m above surface. This was best demonstrated for nighttime observations when artefacts due to solar heating did not occur. For example, the dynamics of a cold air layer was detected in a clear night

  8. Studying the impact of air/brine displacement on acoustic velocities in carbonates. El Amin Mokhtar and Sandra Vega

    NASA Astrophysics Data System (ADS)

    Mokhtar, E.; Vega, D.

    2012-12-01

    The impact of air/brine displacement on acoustic velocities of carbonate rocks is not fully comprehended yet. In order to improve our understanding of this effect, we conducted laboratory measurements of porosity and acoustic velocities (Vp and Vs) under both dry and brine saturated conditions at ambient pressure and temperature. The core plug samples in this study were collected from a hydrocarbon reservoir in the Middle East. A petrographic analysis was also performed on thin sections taken from the core plugs using a microscope and a digital camera. The aim of this analysis was to study depositional facies and the extent of diagenetic overprint that caused the observed variations in rock fabrics. Cross-plots were generated to analyze the trends of behavior between acoustic velocities and porosities taking into account the influence of different rock fabrics, in both dry and brine saturated samples. Acoustic velocities of brine saturated samples were higher than velocities of dry samples, as expected. However, their differences also respond to both, total porosity and carbonate rock fabrics. This result can be attributed to the different carbonate pore structures and rock frames formed during deposition and diagenesis. Similarly, the Vp/Vs ratio cross-plots display an increase in Vp/Vs ratios for the brine saturated samples compared to the dry ones. In conclusion, differences in acoustic velocities between dry and brine saturated carbonate rocks seem to be highly effected by porosity, rock fabric, and fluid content. This information can help to better understand the differences in acoustic response between gas and brine saturated zones in well logs and seismic.

  9. Data Assimilation and Regional Forecasts Using Atmospheric InfraRed Sounder (AIRS) Profiles

    NASA Technical Reports Server (NTRS)

    Chou, Shih-Hung; Zavodsky, Bradley; Jedlovec, Gary

    2009-01-01

    In data sparse regions, remotely-sensed observations can be used to improve analyses, which in turn should lead to better forecasts. One such source comes from the Atmospheric Infrared Sounder (AIRS), which together with the Advanced Microwave Sounding Unit (AMSU), provides temperature and moisture profiles with an accuracy comparable to that of radiosondes. The purpose of this paper is to describe a procedure to optimally assimilate AIRS thermodynamic profiles--obtained from the version 5.0 Earth Observing System (EOS) science team retrieval algorithm-into a regional configuration of the Weather Research and Forecasting (WRF) model using WRF-Var. The paper focuses on development of background error covariances for the regional domain and background field type, a methodology for ingesting AIRS profiles as separate over-land and over-water retrievals with different error characteristics, and utilization of level-by-level quality indicators to select only the highest quality data. The assessment of the impact of the AIRS profiles on WRF-Var analyses will focus on intelligent use of the quality indicators, optimized tuning of the WRF-Var, and comparison of analysis soundings to radiosondes. The analyses will be used to conduct a month-long series of regional forecasts over the continental U.S. The long-tern1 impact of AIRS profiles on forecast will be assessed against verifying radiosonde and stage IV precipitation data.

  10. Data Assimilation and Regional Forecasts using Atmospheric InfraRed Sounder (AIRS) Profiles

    NASA Technical Reports Server (NTRS)

    Zabodsky, Brad; Chou, Shih-Hung; Jedlovec, Gary J.

    2009-01-01

    In data sparse regions, remotely-sensed observations can be used to improve analyses, which in turn should lead to better forecasts. One such source comes from the Atmospheric Infrared Sounder (AIRS), which, together with the Advanced Microwave Sounding Unit (AMSU), provides temperature and moisture profiles with an accuracy comparable to that of radionsondes. The purpose of this poster is to describe a procedure to optimally assimilate AIRS thermodynamic profiles, obtained from the version 5.0 Earth Observing System (EOS) science team retrieval algorithm, into a regional configuration of the Weather Research and Forecasting (WRF) model using WRF-Var. The poster focuses on development of background error covariances for the regional domain and background field type, a methodology for ingesting AIRS profiles as separate over-land and over-water retrievals with different error characteristics, and utilization of level-by-level quality indicators to select only the highest quality data. The assessment of the impact of the AIRS profiles on WRF-Var analyses will focus on intelligent use of the quality indicators, optimized tuning of the WRF-Var, and comparison of analysis soundings to radiosondes. The analyses are used to conduct a month-long series of regional forecasts over the continental U.S. The long-term impact of AIRS profiles on forecast will be assessed against NAM analyses and stage IV precipitation data.

  11. Improving Regional Forecast by Assimilating Atmospheric InfraRed Sounder (AIRS) Profiles into WRF Model

    NASA Technical Reports Server (NTRS)

    Chou, Shih-Hung; Zavodsky, Brad; Jedlovec, Gary J.

    2009-01-01

    In data sparse regions, remotely-sensed observations can be used to improve analyses and produce improved forecasts. One such source comes from the Atmospheric InfraRed Sounder (AIRS), which together with the Advanced Microwave Sounding Unit (AMSU), represents one of the most advanced space-based atmospheric sounding systems. The purpose of this paper is to describe a procedure to optimally assimilate high resolution AIRS profile data into a regional configuration of the Advanced Research WRF (ARW) version 2.2 using WRF-Var. The paper focuses on development of background error covariances for the regional domain and background type, and an optimal methodology for ingesting AIRS temperature and moisture profiles as separate overland and overwater retrievals with different error characteristics. The AIRS thermodynamic profiles are derived from the version 5.0 Earth Observing System (EOS) science team retrieval algorithm and contain information about the quality of each temperature layer. The quality indicators were used to select the highest quality temperature and moisture data for each profile location and pressure level. The analyses were then used to conduct a month-long series of regional forecasts over the continental U.S. The long-term impacts of AIRS profiles on forecast were assessed against verifying NAM analyses and stage IV precipitation data.

  12. Performance of a combined three-hole conductivity probe for void fraction and velocity measurement in air-water flows

    NASA Astrophysics Data System (ADS)

    Borges, João Eduardo; Pereira, Nuno H. C.; Matos, Jorge; Frizell, Kathleen H.

    2010-01-01

    The development of a three-hole pressure probe with back-flushing combined with a conductivity probe, used for measuring simultaneously the magnitude and direction of the velocity vector in complex air-water flows, is described in this paper. The air-water flows envisaged in the current work are typically those occurring around the rotors of impulse hydraulic turbines (like the Pelton and Cross-Flow turbines), where the flow direction is not known prior to the data acquisition. The calibration of both the conductivity and three-hole pressure components of the combined probe in a rig built for the purpose, where the probe was placed in a position similar to that adopted for the flow measurements, will be reported. After concluding the calibration procedure, the probe was utilized in the outside region of a Cross-Flow turbine rotor. The experimental results obtained in the present study illustrate the satisfactory performance of the combined probe, and are encouraging toward its use for characterizing the velocity field of other complex air-water flows.

  13. Near-Surface Shear Wave Velocity Versus Depth Profiles, VS30, and NEHRP Classifications for 27 Sites in Puerto Rico

    USGS Publications Warehouse

    Odum, Jack K.; Williams, Robert A.; Stephenson, William J.; Worley, David M.; von Hillebrandt-Andrade, Christa; Asencio, Eugenio; Irizarry, Harold; Cameron, Antonio

    2007-01-01

    In 2004 and 2005 the Puerto Rico Seismic Network (PRSN), Puerto Rico Strong Motion Program (PRSMP) and the Geology Department at the University of Puerto Rico-Mayaguez (UPRM) collaborated with the U.S. Geological Survey to study near-surface shear-wave (Vs) and compressional-wave (Vp) velocities in and around major urban areas of Puerto Rico. Using noninvasive seismic refraction-reflection profiling techniques, we acquired velocities at 27 locations. Surveyed sites were predominantly selected on the premise that they were generally representative of near-surface materials associated with the primary geologic units located within the urbanized areas of Puerto Rico. Geologic units surveyed included Cretaceous intrusive and volcaniclastic bedrock, Tertiary sedimentary and volcanic units, and Quaternary unconsolidated eolian, fluvial, beach, and lagoon deposits. From the data we developed Vs and Vp depth versus velocity columns, calculated average Vs to 30-m depth (VS30), and derived NEHRP (National Earthquake Hazards Reduction Program) site classifications for all sites except one where results did not reach 30-m depth. The distribution of estimated NEHRP classes is as follows: three class 'E' (VS30 below 180 m/s), nine class 'D' (VS30 between 180 and 360 m/s), ten class 'C' (VS30 between 360 and 760 m/s), and four class 'B' (VS30 greater than 760 m/s). Results are being used to calibrate site response at seismograph stations and in the development of regional and local shakemap models for Puerto Rico.

  14. The effects of tapering on power-force-velocity profiling and jump performance in professional rugby league players.

    PubMed

    de Lacey, James; Brughelli, Matt; McGuigan, Michael; Hansen, Keir; Samozino, Pierre; Morin, Jean-Benoit

    2014-12-01

    The purpose of this study was to investigate the effects of a preseason taper on individual power-force-velocity profiles and jump performance in professional National Rugby League players. Seven professional rugby league players performed concentric squat jumps using ascending loads of 25, 50, 75, 100% body mass before and after a 21-day step taper leading into the in-season. Linear force-velocity relationships were derived, and the following variables were obtained: maximum theoretical velocity (V0), maximum theoretical force (F0), and maximum power (Pmax). The players showed likely-to-very likely increases in F0 (effect size [ES] = 0.45) and Pmax (ES = 0.85) from pre to posttaper. Loaded squat jump height also showed likely-to-most likely increases at each load (ES = 0.83-1.04). The 21-day taper was effective at enhancing maximal power output and jump height performance in professional rugby players, possibly as a result of a recovery from fatigue and thus increased strength capability after a prolonged preseason training period. Rugby league strength and conditioning coaches should consider reducing training volume while maintaining intensity and aerobic conditioning (e.g., step taper) leading into the in-season.

  15. Spectral line profiles of nickel and argon in supernova 1987A - Expansion velocity and electron scattering effects

    NASA Technical Reports Server (NTRS)

    Witteborn, F. C.; Bregman, J. D.; Wooden, D. H.; Pinto, P. A.; Rank, D. M.

    1989-01-01

    Spectra of SN 1987A showing the Ni II 6.634-micron and Ar II 6.983-micron fine-structure lines were obtained from the Kuiper Airborne Observatory in April 1988. The signal-to-noise ratio of 100 near the peaks and resolving power of 200 are sufficient to show the average velocity of expansion from the core of about 1400 km/s and to indicate the range of velocities. An asymmetry in the profiles of both lines and a redshift of the line centroids of about 440 km/s above the 280-km/s recessional velocity of the LMC can be explained in terms of scattering of the photons by electrons in the expanding hydrogen envelope of the supernova. A mass of 0.0030 solar masses of Ni II can be deduced from the line strength of the Ni II line and a mass of 0.0009 solar masses of Ar II from the Ar II line strength.

  16. Microwave temperature profiler for clear air turbulence prediction

    NASA Technical Reports Server (NTRS)

    Gary, Bruce L. (Inventor)

    1992-01-01

    A method is disclosed for determining Richardson Number, Ri, or its reciprocal, RRi, for clear air prediction using measured potential temperature and determining the vertical gradient of potential temperature, d(theta)/dz. Wind vector from the aircraft instrumentation versus potential temperature, dW/D(theta), is determined and multiplies by d(theta)/dz to obtain dW/dz. Richardson number or its reciprocal is then determined from the relationship Ri = K(d theta)/dz divided by (dW/dz squared) for use in detecting a trend toward a threshold value for the purpose of predicting clear air turbulence. Other equations for this basic relationship are disclosed together with the combination of other atmospheric observables using multiple regression techniques.

  17. Effects of air flow directions on composting process temperature profile

    SciTech Connect

    Kulcu, Recep; Yaldiz, Osman

    2008-07-01

    In this study, chicken manure mixed with carnation wastes was composted by using three different air flow directions: R1-sucking (downward), R2-blowing (upward) and R3-mixed. The aim was to find out the most appropriate air flow direction type for composting to provide more homogenous temperature distribution in the reactors. The efficiency of each aeration method was evaluated by monitoring the evolution of parameters such as temperature, moisture content, CO{sub 2} and O{sub 2} ratio in the material and dry material losses. Aeration of the reactors was managed by radial fans. The results showed that R3 resulted in a more homogenous temperature distribution and high dry material loss throughout the composting process. The most heterogeneous temperature distribution and the lowest dry material loss were obtained in R2.

  18. Acquisition of Ice-Tethered Profilers with Velocity (ITP-V) Instruments for Future Arctic Studies

    DTIC Science & Technology

    2015-09-30

    typically sits atop an ice floe, a weighted, wire -rope tether suspended from the surface package, and an instrumented underwater unit that travels...up and down the wire tether (Figure 1). The current design of the ITP surface expression is a conical-shaped buoy that houses a controller, inductive...jacketed wire rope tether and end weight should the ice fracture or melt, and to provide modest protection in the event of ice ridging. The profiler

  19. A Preliminary Evaluation of Near-Transducer Velocities Collected with Low-Blank Acoustic Doppler Current Profiler

    USGS Publications Warehouse

    Gartner, J.W.; Ganju, N.K.; ,

    2002-01-01

    Many streams and rivers for which the US Geological Survey must provide discharge measurements are too shallow to apply existing acoustic Doppler current profiler techniques for flow measurements of satisfactory quality. Because the same transducer is used for both transmitting and receiving acoustic signals in most Doppler current profilers, some small time delay is required for acoustic "ringing" to be damped out of transducers before meaningful measurements can be made. The result of that time delay is that velocity measurements cannot be made close to the transducer thus limiting the usefulness of these instruments in shallow regions. Manufacturers and users are constantly striving for improvements to acoustic instruments which would permit useful discharge measurements in shallow rivers and streams that are still often measured with techniques and instruments more than a century old. One promising area of advance appeared to be reduction of time delay (blank) required between transmitting and receiving signals during acoustic velocity measurements. Development of a low- or zero-blank transducer by RD Instruments3 held promise that velocity measurements could be made much closer to the transducer and thus in much shallower water. Initial experience indicates that this is not the case; limitation of measurement quality appears to be related to the physical presence of the transducer itself within the flow field. The limitation may be the result of changes to water flow pattern close to the transducer rather than transducer ringing characteristics as a function of blanking distance. Results of field experiments are discussed that support this conclusion and some minimum measurement distances from transducer are suggested based on water current speed and ADCP sample modes.

  20. Convective cloud vertical velocity and mass-flux characteristics from radar wind profiler observations during GoAmazon2014/5

    DOE PAGES

    Giangrande, Scott E.; Toto, Tami; Jensen, Michael P.; ...

    2016-10-21

    A radar wind profiler (RWP) data set collected during the 2 year Department of Energy Atmospheric Radiation Measurement Observations and Modeling of the Green Ocean Amazon (GoAmazon2014/5) campaign is used to estimate convective cloud vertical velocity, area fraction, and mass flux profiles. Vertical velocity observations are presented using cumulative frequency histograms and weighted mean profiles to provide insights in a manner suitable for global climate model scale comparisons (spatial domains from 20 km to 60 km). Convective profile sensitivity to changes in environmental conditions and seasonal regime controls is also considered. Aggregate and ensemble average vertical velocity, convective area fraction,more » and mass flux profiles, as well as magnitudes and relative profile behaviors, are found consistent with previous studies. Updrafts and downdrafts increase in magnitude with height to midlevels (6 to 10 km), with updraft area also increasing with height. Updraft mass flux profiles similarly increase with height, showing a peak in magnitude near 8 km. Downdrafts are observed to be most frequent below the freezing level, with downdraft area monotonically decreasing with height. Updraft and downdraft profile behaviors are further stratified according to environmental controls. These results indicate stronger vertical velocity profile behaviors under higher convective available potential energy and lower low-level moisture conditions. Sharp contrasts in convective area fraction and mass flux profiles are most pronounced when retrievals are segregated according to Amazonian wet and dry season conditions. Lastly, during this deployment, wet season regimes favored higher domain mass flux profiles, attributed to more frequent convection that offsets weaker average convective cell vertical velocities.« less

  1. Convective cloud vertical velocity and mass-flux characteristics from radar wind profiler observations during GoAmazon2014/5

    SciTech Connect

    Giangrande, Scott E.; Toto, Tami; Jensen, Michael P.; Bartholomew, Mary Jane; Feng, Zhe; Protat, Alain; Williams, Christopher R.; Schumacher, Courtney; Machado, Luiz

    2016-10-21

    A radar wind profiler (RWP) data set collected during the 2 year Department of Energy Atmospheric Radiation Measurement Observations and Modeling of the Green Ocean Amazon (GoAmazon2014/5) campaign is used to estimate convective cloud vertical velocity, area fraction, and mass flux profiles. Vertical velocity observations are presented using cumulative frequency histograms and weighted mean profiles to provide insights in a manner suitable for global climate model scale comparisons (spatial domains from 20 km to 60 km). Convective profile sensitivity to changes in environmental conditions and seasonal regime controls is also considered. Aggregate and ensemble average vertical velocity, convective area fraction, and mass flux profiles, as well as magnitudes and relative profile behaviors, are found consistent with previous studies. Updrafts and downdrafts increase in magnitude with height to midlevels (6 to 10 km), with updraft area also increasing with height. Updraft mass flux profiles similarly increase with height, showing a peak in magnitude near 8 km. Downdrafts are observed to be most frequent below the freezing level, with downdraft area monotonically decreasing with height. Updraft and downdraft profile behaviors are further stratified according to environmental controls. These results indicate stronger vertical velocity profile behaviors under higher convective available potential energy and lower low-level moisture conditions. Sharp contrasts in convective area fraction and mass flux profiles are most pronounced when retrievals are segregated according to Amazonian wet and dry season conditions. Lastly, during this deployment, wet season regimes favored higher domain mass flux profiles, attributed to more frequent convection that offsets weaker average convective cell vertical velocities.

  2. Convective cloud vertical velocity and mass-flux characteristics from radar wind profiler observations during GoAmazon2014/5

    NASA Astrophysics Data System (ADS)

    Giangrande, Scott E.; Toto, Tami; Jensen, Michael P.; Bartholomew, Mary Jane; Feng, Zhe; Protat, Alain; Williams, Christopher R.; Schumacher, Courtney; Machado, Luiz

    2016-11-01

    A radar wind profiler data set collected during the 2 year Department of Energy Atmospheric Radiation Measurement Observations and Modeling of the Green Ocean Amazon (GoAmazon2014/5) campaign is used to estimate convective cloud vertical velocity, area fraction, and mass flux profiles. Vertical velocity observations are presented using cumulative frequency histograms and weighted mean profiles to provide insights in a manner suitable for global climate model scale comparisons (spatial domains from 20 km to 60 km). Convective profile sensitivity to changes in environmental conditions and seasonal regime controls is also considered. Aggregate and ensemble average vertical velocity, convective area fraction, and mass flux profiles, as well as magnitudes and relative profile behaviors, are found consistent with previous studies. Updrafts and downdrafts increase in magnitude with height to midlevels (6 to 10 km), with updraft area also increasing with height. Updraft mass flux profiles similarly increase with height, showing a peak in magnitude near 8 km. Downdrafts are observed to be most frequent below the freezing level, with downdraft area monotonically decreasing with height. Updraft and downdraft profile behaviors are further stratified according to environmental controls. These results indicate stronger vertical velocity profile behaviors under higher convective available potential energy and lower low-level moisture conditions. Sharp contrasts in convective area fraction and mass flux profiles are most pronounced when retrievals are segregated according to Amazonian wet and dry season conditions. During this deployment, wet season regimes favored higher domain mass flux profiles, attributed to more frequent convection that offsets weaker average convective cell vertical velocities.

  3. The expansion velocities of laser-produced plasmas determined from extreme ultraviolet spectral line profiles

    NASA Technical Reports Server (NTRS)

    Feldman, U.; Doschek, G. A.; Behring, W. E.; Cohen, L.

    1977-01-01

    The expansion of laser-produced plasma is determined from the shapes of spectral lines of highly ionized iron emitted in the extreme ultraviolet. The plasmas were produced by focusing the pulse from a Nd:glass laser onto solid planar targets, and spectra were recorded with a high-resolution grazing-incidence spectrograph. From the Doppler broadening of lines of Fe XX and Fe XXI, expansion velocities of about 830 km/s were determined. The relative time-averaged ion abundances of Fe XVIII, Fe XIX, Fe XX, and Fe XXI are estimated for three different spectra. The abundances do not differ by more than a factor of 4 for any of the spectra.

  4. Velocity Profile Characterization for the 5-CM Agent Fate Wind Tunnels

    DTIC Science & Technology

    2008-01-01

    a drop or drops of agent are deposited on a substrate specimen. A portion of the agent forms a sessile drop on the surface while the remainder is...substrate with the resulting vapor carried away by the air stream. As time passes, the sessile drop on the surface completely volatilizes leaving only the...window is located on the side of the test section. It is flush with the test section floor to provide an unobstructed side view of the sessile drop of

  5. The effect of inflow velocity profiles on the performance of supersonic ejector nozzles

    NASA Technical Reports Server (NTRS)

    Bishop, A. R.

    1981-01-01

    The design of supersonic nozzles is becoming increasingly complex as conflicting requirements for low noise, higher efficiency, and wider operating range are driving the designer toward more variable geometry and multiple stream flows. Analysis techniques must be modified and expanded to take into account these additional complexities and still retain the rapid computational rate necessary for optimization and design studies. A nozzle analysis must handle more flow streams, more complex geometries, and more highly distorted initial profiles. This paper discusses some modifications to a method for calculating the performance characteristics of supersonic ejector nozzles and demonstrates the improvement in results the modifications provide.

  6. Assimilation of Quality Controlled AIRS Temperature Profiles using the NCEP GFS

    NASA Technical Reports Server (NTRS)

    Susskind, Joel; Reale, Oreste; Iredell, Lena; Rosenberg, Robert

    2013-01-01

    We have previously conducted a number of data assimilation experiments using AIRS Version-5 quality controlled temperature profiles as a step toward finding an optimum balance of spatial coverage and sounding accuracy with regard to improving forecast skill. The data assimilation and forecast system we used was the Goddard Earth Observing System Model , Version-5 (GEOS-5) Data Assimilation System (DAS), which represents a combination of the NASA GEOS-5 forecast model with the National Centers for Environmental Prediction (NCEP) operational Grid Point Statistical Interpolation (GSI) global analysis scheme. All analyses and forecasts were run at a 0.5deg x 0.625deg spatial resolution. Data assimilation experiments were conducted in four different seasons, each in a different year. Three different sets of data assimilation experiments were run during each time period: Control; AIRS T(p); and AIRS Radiance. In the "Control" analysis, all the data used operationally by NCEP was assimilated, but no AIRS data was assimilated. Radiances from the Aqua AMSU-A instrument were also assimilated operationally by NCEP and are included in the "Control". The AIRS Radiance assimilation adds AIRS observed radiance observations for a select set of channels to the data set being assimilated, as done operationally by NCEP. In the AIRS T(p) assimilation, all information used in the Control was assimilated as well as Quality Controlled AIRS Version-5 temperature profiles, i.e., AIRS T(p) information was substituted for AIRS radiance information. The AIRS Version-5 temperature profiles were presented to the GSI analysis as rawinsonde profiles, assimilated down to a case-by-case appropriate pressure level p(sub best) determined using the Quality Control procedure. Version-5 also determines case-by-case, level-by-level error estimates of the temperature profiles, which were used as the uncertainty of each temperature measurement. These experiments using GEOS-5 have shown that forecasts

  7. Size and Velocity Characteristics of Droplets Generated by Thin Steel Slab Continuous Casting Secondary Cooling Air-Mist Nozzles

    NASA Astrophysics Data System (ADS)

    Minchaca M, J. I.; Castillejos E, A. H.; Acosta G, F. A.

    2011-06-01

    Direct spray impingement of high temperature surfaces, 1473 K to 973 K (1200 °C to 700 °C), plays a critical role in the secondary cooling of continuously cast thin steel slabs. It is known that the spray parameters affecting the local heat flux are the water impact flux w as well as the droplet velocity and size. However, few works have been done to characterize the last two parameters in the case of dense mists ( i.e., mists with w in the range of 2 to 90 L/m2s). This makes it difficult to rationalize how the nozzle type and its operating conditions must be selected to control the cooling process. In the present study, particle/droplet image analysis was used to determine the droplet size and velocity distributions simultaneously at various locations along the major axis of the mist cross section at a distance where the steel strand would stand. The measurements were carried out at room temperature for two standard commercial air-assisted nozzles of fan-discharge type operating over a broad range of conditions of practical interest. To achieve statistically meaningful samples, at least 6000 drops were analyzed at each location. Measuring the droplet size revealed that the number and volume frequency distributions were fitted satisfactorily by the respective log-normal and Nukiyama-Tanasawa distributions. The correlation of the parameters of the distribution functions with the water- and air-nozzle pressures allowed for reasonable estimation of the mean values of the size of the droplets generated. The ensemble of measurements across the mist axis showed that the relationship between the droplet velocity and the diameter exhibited a weak positive correlation. Additionally, increasing the water flow rate at constant air pressure caused a decrease in the proportion of the water volume made of finer droplets, whereas the volume proportion of faster droplets augmented until the water flow reached a certain value, after which it decreased. Diminishing the air

  8. Measurement of velocities with an acoustic velocity meter, one side-looking and two upward-looking acoustic Doppler current profilers in the Chicago Sanitary and Ship Canal, Romeoville, Illinois

    USGS Publications Warehouse

    Oberg, Kevin A.; Duncker, James J.

    1999-01-01

    In 1998, a prototype 300 kHz, side-looking Acoustic Doppler Current Profiler (ADCP) was deployed in the Chicago Sanitary and Ship Canal (CSSC) at Romeoville, Illinois. Additionally, two upward-looking ADCP's were deployed in the same acoustic path as the side-looking ADCP and in the reach defined by the upstream and downstream acoustic velocity meter (AVM) paths. All three ADCP's were synchronized to the AVM clock at the gaging station so that data were sampled simultaneously. The three ADCP's were deployed for six weeks measuring flow velocities from 0.0 to 2.5 ft/s. Velocities measured by each ADCP were compared to AVM path velocities and to velocities measured by the other ADCP's.

  9. Air Reactions to Objects Moving at Rates Above the Velocity of Sound with Application to the Air Propeller

    NASA Technical Reports Server (NTRS)

    Reed, S Albert

    1922-01-01

    There has been a tradition general among aeronautical engineers that a critical point exists for tip speeds at or near the velocity of sound, indicating a physical limit in the use of propellers at higher tip speeds; the idea being that something would occur analogous to what is known in marine propellers as cavitation. In the examination of the physics pertaining to both propellers and projectiles moving at or above 1100 feet per second, the conclusion was reached by the author that there is no reason for the existence of such a critical point and that, if it had been noted by observers it was not inherent in the phenomena revealed, but rather due to a particular shape or proportion of the projectile and that, with properly proportioned sections, it would not exist.

  10. Demonstrating the Operational Value of Atmospheric Infrared Sounder (AIRS) Profiles in the Pre-Convective Environment

    NASA Technical Reports Server (NTRS)

    Kozlowski, Danielle; Zavodsky, Bradley; Stano, Geoffrey; Jedlovec, Gary

    2011-01-01

    The Short-term Prediction Research and Transition (SPoRT) is a project to transition those NASA observations and research capabilities to the weather forecasting community to improve the short-term regional forecasts. This poster reviews the work to demonstrate the value to these forecasts of profiles from the Atmospheric Infrared Sounder (AIRS) instrument on board the Aqua satellite with particular assistance in predicting thunderstorm forecasts by the profiles of the pre-convective environment.

  11. Transport properties of graphene across strain-induced nonuniform velocity profiles

    NASA Astrophysics Data System (ADS)

    Pellegrino, F. M. D.; Angilella, G. G. N.; Pucci, R.

    2011-11-01

    We consider the effect of uniaxial strain on ballistic transport in graphene, across single and multiple tunneling barriers. Specifically, we show that applied strain not only shifts the position of the Dirac points in reciprocal space, but also induces a deformation of the Dirac cones, and that both effects are of the same order on the applied strain intensity. We therefore study the deviations thereby induced on the angular dependence of the tunneling transmission across a single barrier, as well as on the conductivity and Fano factor across a single barrier and a superstructure of several, periodically repeated, such sharp barriers. Our model is generalized to the case of nonuniform barriers, where either the strain or the gate potential profiles may depend continuously on position. This should afford a more accurate description of realistic “origami” nanodevices based on graphene, where “foldings” are expected to involve several lattice spacings.

  12. A Holographic Interferometer System for Measuring Density Profiles in High-Velocity Flows

    NASA Technical Reports Server (NTRS)

    Burner, Alpheus W.

    1972-01-01

    This paper describes a holographic interferometric technique for obtaining density measurements across a test gas that is traveling at a velocity of over 5500 meters per second in an expansion tube facility. Interferometric data describing the flow in the test section are obtained using a long coherence length cw argon laser in a holographic system and a rotating drum camera recorder. The object beam, which passes through the test section, intersects the reference beam at a small angle (5 degrees) to form an interference pattern of about 170 lines per millimeter, and is recorded as a hologram. Before a test, this hologram is placed in its original position and rotated slightly so that an interference pattern is generated by the intersection of the reconstructed and real-time object beams. This interference pattern is adjusted to a series of bright, horizontal fringes having a spatial frequency of about 5 fringes per centimeter. During the few milliseconds it takes the test gas to pass through the test section, variations in the gas density across the 8.4-centimeter test section produce phase variations in the object beam and result in a varying interference pattern. A rotating drum camera with a 0.15-millimeter slit aligned perpendicular to the fringes is used to record the varying fringe shifts with a time resolution of about 3 microseconds. The average gas density across the test section is determined by measuring these fringe shifts.

  13. A Hybrid Windkessel Model of Blood Flow in Arterial Tree Using Velocity Profile Method

    NASA Astrophysics Data System (ADS)

    Aboelkassem, Yasser; Virag, Zdravko

    2016-11-01

    For the study of pulsatile blood flow in the arterial system, we derived a coupled Windkessel-Womersley mathematical model. Initially, a 6-elements Windkessel model is proposed to describe the hemodynamics transport in terms of constant resistance, inductance and capacitance. This model can be seen as a two compartment model, in which the compartments are connected by a rigid pipe, modeled by one inductor and resistor. The first viscoelastic compartment models proximal part of the aorta, the second elastic compartment represents the rest of the arterial tree and aorta can be seen as the connection pipe. Although the proposed 6-elements lumped model was able to accurately reconstruct the aortic pressure, it can't be used to predict the axial velocity distribution in the aorta and the wall shear stress and consequently, proper time varying pressure drop. We then modified this lumped model by replacing the connection pipe circuit elements with a vessel having a radius R and a length L. The pulsatile flow motions in the vessel are resolved instantaneously along with the Windkessel like model enable not only accurate prediction of the aortic pressure but also wall shear stress and frictional pressure drop. The proposed hybrid model has been validated using several in-vivo aortic pressure and flow rate data acquired from different species such as, humans, dogs and pigs. The method accurately predicts the time variation of wall shear stress and frictional pressure drop. Institute for Computational Medicine, Dept. Biomedical Engineering.

  14. Computational fluid dynamics investigation of human aspiration in low velocity air: orientation effects on nose-breathing simulations.

    PubMed

    Anderson, Kimberly R; Anthony, T Renée

    2014-06-01

    An understanding of how particles are inhaled into the human nose is important for developing samplers that measure biologically relevant estimates of exposure in the workplace. While previous computational mouth-breathing investigations of particle aspiration have been conducted in slow moving air, nose breathing still required exploration. Computational fluid dynamics was used to estimate nasal aspiration efficiency for an inhaling humanoid form in low velocity wind speeds (0.1-0.4 m s(-1)). Breathing was simplified as continuous inhalation through the nose. Fluid flow and particle trajectories were simulated over seven discrete orientations relative to the oncoming wind (0, 15, 30, 60, 90, 135, 180°). Sensitivities of the model simplification and methods were assessed, particularly the placement of the recessed nostril surface and the size of the nose. Simulations identified higher aspiration (13% on average) when compared to published experimental wind tunnel data. Significant differences in aspiration were identified between nose geometry, with the smaller nose aspirating an average of 8.6% more than the larger nose. Differences in fluid flow solution methods accounted for 2% average differences, on the order of methodological uncertainty. Similar trends to mouth-breathing simulations were observed including increasing aspiration efficiency with decreasing freestream velocity and decreasing aspiration with increasing rotation away from the oncoming wind. These models indicate nasal aspiration in slow moving air occurs only for particles <100 µm.

  15. Effects of air velocity and clothing combination on heating efficiency of an electrically heated vest (EHV): a pilot study.

    PubMed

    Wang, Faming; Gao, Chuansi; Holmér, Ingvar

    2010-09-01

    Cold endangers the heat balance of the human body. Protective clothing is the natural and most common equipment against cold stress. However, clothing for cold protection may be bulky and heavy, affecting human performance and increasing the work load. In such cases, a heated garment with built-in heating elements may be helpful. This pilot study presents a method based on a thermal manikin to investigate the effects of air velocity and clothing combination on the heating efficiency of an electrically heated vest (EHV). An infrared thermal camera was used to detect surface temperature distributions of the EHV on the front and back. Results show that the heating efficiency of the EHV decreases with increasing air velocity. Changes in EHV sequence in the three-layer clothing combination also significantly affect the heating efficiency: it increases with the increasing number of layers on top of the EHV. The highest mean temperature on the inner surface of the EHV was 40.2 degrees C, which indicates that it is safe for the wearers. For the EHV to heat the human body effectively, we suggest that it be worn as a middle layer. Finally, the EHV is especially suitable for occupational groups whose metabolic rate is below 1.9 Mets.

  16. Effect of airstream velocity on mean drop diameters of water sprays produced by pressure and air atomizing nozzles. [for combustion studies

    NASA Technical Reports Server (NTRS)

    Ingebo, R. D.

    1977-01-01

    A scanning radiometer was used to determine the effect of airstream velocity on the mean drop diameter of water sprays produced by pressure atomizing and air atomizing fuel nozzles used in previous combustion studies. Increasing airstream velocity from 23 to 53.4 meters per second reduced the Sauter mean diameter by approximately 50 percent with both types of fuel nozzles. The use of a sonic cup attached to the tip of an air assist nozzle reduced the Sauter mean diameter by approximately 40 percent. Test conditions included airstream velocities of 23 to 53.4 meters per second at 293 K and atmospheric pressure.

  17. Experimental determination of the velocity and strain rate field in a laminar H2/Air counter-flow diffusion flame via LDA

    NASA Technical Reports Server (NTRS)

    Yeo, S. H.; Dancey, C. L.

    1991-01-01

    Measurements of the axial and radial components of velocity on the air side of stagnation in an axisymmetric H2/Air laminar counter-flow diffusion flame are reported. Results include the two-dimensional velocity field and computed velocity gradients (strain rates) along the stagnation streamline at two 'characteristic' strain rates, below the extinction limit. The measurements generally verify the modeling assumptions appropriate to the model of Kee et al. (1988). The 'traditional' potential flow model is not consistent with the measured results.

  18. High-resolution Vertical Profiling of Ocean Velocity and Water Properties Under Hurricane Frances in September 2004

    NASA Astrophysics Data System (ADS)

    Sanford, T. B.; D'Asarp, E. A.; Girton, J. B.; Price, J. F.; Webb, D. C.

    2006-12-01

    In ONR's CBLAST Hurricane research program observations were made of the upper ocean's response to Hurricane Frances. Three EM-APEX floats (velocity sensing versions of Webb Research APEX floats) and two Lagrangian floats were deployed north of Hispaniola from a C-130 aircraft ahead of Hurricane Frances in September 2004. The EM-APEX floats measured T, S and V over the upper 500 m starting about a day before the storm's arrival. The Lagrangian floats measured temperature and salinity while following the three- dimensional boundary layer turbulence in the upper 40 m. One EM-APEX float was directly under the track of the storm's eye, another EM-APEX and two Lagrangian floats went in about 50 km to the right of the track (where the surface winds are strongest) and the third float was about 100 km to the right. The EM-APEX floats profiled for 10 hours from the surface to 200 m, then continued profiling between 35 and 200 m with excursions to 500 m every half inertial period. After 5 days, the EM-APEX floats surfaced and transmitted the accumulated processed observations, then the floats profiled to 500 m every half inertial period until recovered early in October aided by GPS and Iridium. The float array sampled in unprecedented detail the upper-ocean turbulence, momentum, and salt and heat changes in response to the hurricane. The buildup of surface gravity waves in advance of the storm was also observed in the velocity profiles, with significant wave heights of up to 11 m. Rapid acceleration of inertial currents in the surface mixing layer (SML) to over 1 m/s stimulated vertical mixing by shear instability at the SML base, as indicated by low Richardson numbers and SML deepening from about 40 m to 120 m under the strongest wind forcing. Surface cooling of about 2.5 C was primarily due to the SML deepening and entrainment of colder water, with a small contribution from surface heat flux. Intense inertial pumping was observed under the eye, with vertical excursions of

  19. Mapping refuse profile in Singapore old dumping ground through electrical resistivity, S-wave velocity and geotechnical monitoring.

    PubMed

    Yin, Ke; Tong, Huan Huan; Noh, Omar; Wang, Jing-Yuan; Giannis, Apostolos

    2015-03-01

    The purpose of this study was to track the refuse profile in Lorong Halus Dumping Ground, the largest landfill in Singapore, by electrical resistivity and surface wave velocity after 25 years of closure. Data were analyzed using an orthogonal set of plots by spreading 24 lines in two perpendicular geophone-orientation directions. Both geophysical techniques determined that refuse boundary depth was 13 ± 2 m. The refuse boundary revealed a certain degree of variance, mainly ascribed to the different principle of measurements, as well as the high heterogeneity of the subsurface. Discrepancy was higher in spots with greater heterogeneity. 3D analysis was further conducted detecting refuse pockets, leachate mounding and gas channels. Geotechnical monitoring (borehole) confirmed geophysical outcomes tracing different layers such as soil capping, decomposed refuse materials and inorganic wastes. Combining the geophysical methods with borehole monitoring, a comprehensive layout of the dumping site was presented showing the hot spots of interests.

  20. Determination of the velocity, density, maximum flux, and enthalpy profiles for a very high temperature arc jet nozzle flow

    NASA Astrophysics Data System (ADS)

    Kopp, Robert William

    1989-06-01

    Hypervelocity flows for velocities is excess of 1.4 km/sec (Mach 5) require very high stagnation temperature to avoid liquefaction. The arc heater wind tunnel was designed to provide such flows. The electric-arc driven wind tunnel can develop stagnation temperatures up to 13,000 K which will produce hypervelocity flows up to 7 km/sec (earth orbital speed). The nature of the flow, however, is such that the high temperature source flow may cause severe gradients at the nozzle exit. In order to perform aerothermodynamic tests the characterization of the flow in the test section is required. This paper experimentally determines the stream profiles for an arcjet wind tunnel conical nozzle directly from calorimetry and pitot probe surveys.

  1. Regional Precipitation Forecast with Atmospheric InfraRed Sounder (AIRS) Profile Assimilation

    NASA Technical Reports Server (NTRS)

    Chou, S.-H.; Zavodsky, B. T.; Jedloved, G. J.

    2010-01-01

    Advanced technology in hyperspectral sensors such as the Atmospheric InfraRed Sounder (AIRS; Aumann et al. 2003) on NASA's polar orbiting Aqua satellite retrieve higher vertical resolution thermodynamic profiles than their predecessors due to increased spectral resolution. Although these capabilities do not replace the robust vertical resolution provided by radiosondes, they can serve as a complement to radiosondes in both space and time. These retrieved soundings can have a significant impact on weather forecasts if properly assimilated into prediction models. Several recent studies have evaluated the performance of specific operational weather forecast models when AIRS data are included in the assimilation process. LeMarshall et al. (2006) concluded that AIRS radiances significantly improved 500 hPa anomaly correlations in medium-range forecasts of the Global Forecast System (GFS) model. McCarty et al. (2009) demonstrated similar forecast improvement in 0-48 hour forecasts in an offline version of the operational North American Mesoscale (NAM) model when AIRS radiances were assimilated at the regional scale. Reale et al. (2008) showed improvements to Northern Hemisphere 500 hPa height anomaly correlations in NASA's Goddard Earth Observing System Model, Version 5 (GEOS-5) global system with the inclusion of partly cloudy AIRS temperature profiles. Singh et al. (2008) assimilated AIRS temperature and moisture profiles into a regional modeling system for a study of a heavy rainfall event during the summer monsoon season in Mumbai, India. This paper describes an approach to assimilate AIRS temperature and moisture profiles into a regional configuration of the Advanced Research Weather Research and Forecasting (WRF-ARW) model using its three-dimensional variational (3DVAR) assimilation system (WRF-Var; Barker et al. 2004). Section 2 describes the AIRS instrument and how the quality indicators are used to intelligently select the highest-quality data for assimilation

  2. Vertical profile of tritium concentration in air during a chronic atmospheric HT release.

    PubMed

    Noguchi, Hiroshi; Yokoyama, Sumi

    2003-03-01

    The vertical profiles of tritium gas and tritiated water concentrations in air, which would have an influence on the assessment of tritium doses as well as on the environmental monitoring of tritium, were measured in a chronic tritium gas release experiment performed in Canada in 1994. While both of the profiles were rather uniform during the day because of atmospheric mixing, large gradients of the profiles were observed at night. The gradient coefficients of the profiles were derived from the measurements. Correlations were analyzed between the gradient coefficients and meteorological conditions: solar radiation, wind speed, and turbulent diffusivity. It was found that the solar radiation was highly correlated with the gradient coefficients of tritium gas and tritiated water profiles and that the wind speed and turbulent diffusivity showed weaker correlations with those of tritiated water profiles. A one-dimensional tritium transport model was developed to analyze the vertical diffusion of tritiated water re-emitted from the ground into the atmosphere. The model consists of processes of tritium gas deposition to soil including oxidation into tritiated water, reemission of tritiated water, dilution of tritiated water in soil by rain, and vertical diffusion of tritiated water in the atmosphere. The model accurately represents the accumulation of tritiated water in soil water and the time variations and vertical profiles of tritiated water concentrations in air.

  3. Lamb wave dispersion and anisotropy profiling of composite plates via non-contact air-coupled and laser ultrasound

    NASA Astrophysics Data System (ADS)

    Harb, M. S.; Yuan, F. G.

    2015-03-01

    Conventional ultrasound inspection has been a standard non-destructive testing method for providing an in-service evaluation and noninvasive means of probing the interior of a structure. In particular, measurement of the propagation characteristics of Lamb waves allows inspection of plates that are typical components in aerospace industry. A rapid, complete non-contact hybrid approach for excitation and detection of Lamb waves is presented and applied for non-destructive evaluation of composites. An air-coupled transducer (ACT) excites ultrasonic waves on the surface of a composite plate, generating different propagating Lamb wave modes and a laser Doppler vibrometer (LDV) is used to measure the out-of-plane velocity of the plate. This technology, based on direct waveform imaging, focuses on measuring dispersive curves for A0 mode in a composite laminate and its anisotropy. A two-dimensional fast Fourier transform (2D-FFT) is applied to out-of-plane velocity data captured experimentally using LDV to go from the time-spatial domain to frequency-wavenumber domain. The result is a 2D array of amplitudes at discrete frequencies and wavenumbers for A0 mode in a given propagation direction along the composite. The peak values of the curve are then used to construct frequency wavenumber and phase velocity dispersion curves, which are also obtained directly using Snell's law and the incident angle of the excited ultrasonic waves. A high resolution and strong correlation between numerical and experimental results are observed for dispersive curves with Snell's law method in comparison to 2D-FFT method. Dispersion curves as well as velocity curves for the composite plate along different directions of wave propagation are measured. The visual read-out of the dispersion curves at different propagation directions as well as the phase velocity curves provide profiling and measurements of the composite anisotropy. The results proved a high sensitivity of the air-coupled and laser

  4. A phenomenological model of the muon density profile on the ground of very inclined air showers

    NASA Astrophysics Data System (ADS)

    Dembinski, H. P.; Billoir, P.; Deligny, O.; Hebbeker, T.

    2010-09-01

    Ultra-high energy cosmic rays generate extensive air showers in Earth's atmosphere. A standard approach to reconstruct the energy of an ultra-high energy cosmic rays is to sample the lateral profile of the particle density on the ground of the air shower with an array of surface detectors. For cosmic rays with large inclinations, this reconstruction is based on a model of the lateral profile of the muon density observed on the ground, which is fitted to the observed muon densities in individual surface detectors. The best models for this task are derived from detailed Monte-Carlo simulations of the air shower development. We present a phenomenological parametrization scheme which allows to derive a model of the average lateral profile of the muon density directly from a fit to a set of individual Monte-Carlo simulated air showers. The model reproduces the detailed simulations with a high precision. As an example, we generate a muon density model which is valid in the energy range 10 18 eV < E < 10 20 eV and the zenith angle range 60°<θ<90°. We will further demonstrate a way to speed up the simulation of such muon profiles by three orders of magnitude, if only the muons in the shower are of interest.

  5. Heating, Ventilation, Air-conditioning, and Refrigeration. Ohio's Competency Analysis Profile.

    ERIC Educational Resources Information Center

    Ohio State Univ., Columbus. Vocational Instructional Materials Lab.

    Developed through a modified DACUM (Developing a Curriculum) process involving business, industry, labor, and community agency representatives in Ohio, this document is a comprehensive and verified employer competency profile for heating, ventilation, air conditioning, and refrigeration occupations. The list contains units (with and without…

  6. Firn air-content of Larsen C Ice Shelf, Antarctic Peninsula, from seismic velocities, borehole surveys and firn modelling

    NASA Astrophysics Data System (ADS)

    Kulessa, Bernd; Brisbourne, Alex; Booth, Adam; Kuipers Munneke, Peter; Bevan, Suzanne; Luckman, Adrian; Hubbard, Bryn; Gourmelen, Noel; Palmer, Steve; Holland, Paul; Ashmore, David; Shepherd, Andrew

    2016-04-01

    The rising surface temperature of Antarctic Peninsula ice shelves is strongly implicated in ice shelf disintegration, by exacerbating the compaction of firn layers. Firn compaction is expected to warm the ice column and, given sufficiently wet and compacted layers, to allow meltwater to penetrate into surface crevasses and thus enhance hydrofracture potential. Integrating seismic refraction surveys with borehole neutron and firn core density logging, we reveal vertical and horizontal changes in firn properties across Larsen C Ice Shelf. Patterns of firn air-content derived from seismic surveys are broadly similar to those estimated previously from airborne radar and satellite data. Specifically, these estimates show greater firn compaction in the north and landward inlets compared to the south, although spatial gradients in seismic-derived air-contents are less pronounced than those previously inferred. Firn thickness is less than 10 m in the extreme northwest of Larsen C, in Cabinet Inlet, yet exceeds 40 m in the southeast, suggesting that the inlet is a focus of firn compaction; indeed, buried layers of massive refrozen ice were observed in 200 MHz GPR data in Cabinet and Whirlwind Inlets during a field campaign in the 2014-15 austral summer. Depth profiles of firn density provide a reasonable fit with those derived from closely-located firn cores and neutron probe data. Our model of firn structure is driven by RACMO and includes a 'bucket'-type hydrological implementation, and simulates the depth-density profiles in the inlets well. Discrepancies between measured and modelled depth-density profiles become progressively greater towards the ice-shelf front. RACMO incorrectly simulates the particular leeward (sea-ice-influenced) microclimate of the shallow boundary layer, leading to excess melt and/or lack of snowfall. The spatial sampling density of our seismic observations will be augmented following a further field campaign in the 2016-17 austral summer

  7. Assimilation of Atmospheric InfraRed Sounder (AIRS) Profiles using WRF-Var

    NASA Technical Reports Server (NTRS)

    Zavodsky, Brad; Jedlovec, Gary J.; Lapenta, William

    2008-01-01

    The Weather Research and Forecasting (WRF) model contains a three-dimensional variational (3DVAR) assimilation system (WRF-Var), which allows a user to join data from multiple sources into one coherent analysis. WRF-Var combines observations with a background field traditionally generated using a previous model forecast through minimization of a cost function. In data sparse regions, remotely-sensed observations may be able to improve analyses and produce improved forecasts. One such source comes from the Atmospheric Infrared Sounder (AIRS), which together with the Advanced Microwave Sounding Unit (AMSU), represents one of the most advanced space-based atmospheric sounding systems. The combined AIRS/AMSU system provides radiance measurements used as input to a sophisticated retrieval scheme which has been shown to produce temperature profiles with an accuracy of 1 K over 1 km layers and humidity profiles with accuracy of 15% in 2 km layers in both clear and partly cloudy conditions. The retrieval algorithm also provides estimates of the accuracy of the retrieved values at each pressure level, allowing the user to select profiles based on the required error tolerances of the application. The purpose of this paper is to describe a procedure to optimally assimilate high-resolution AIRS profile data into a regional configuration of the Advanced Research WRF (ARW) version 2.2 using WRF-Var. The paper focuses on development of background error covariances for the regional domain and background field type using gen_be and an optimal methodology for ingesting AIRS temperature and moisture profiles as separate overland and overwater retrievals with different error characteristics in the WRF-Var. The AIRS thermodynamic profiles are obtained from the version 5.0 Earth Observing System (EOS) science team retrieval algorithm and contain information about the quality of each temperature layer. The quality indicators are used to select the highest quality temperature and moisture

  8. Elliptical galaxies with rapidly decreasing velocity dispersion profiles: NMAGIC models and dark halo parameter estimates for NGC 4494

    NASA Astrophysics Data System (ADS)

    Morganti, Lucia; Gerhard, Ortwin; Coccato, Lodovico; Martinez-Valpuesta, Inma; Arnaboldi, Magda

    2013-06-01

    NGC 4494 is one of several intermediate-luminosity elliptical galaxies inferred to have an unusually diffuse dark matter halo. We use the χ2-made-to-measure particle code NMAGIC to construct axisymmetric models of NGC 4494 from photometric and various kinematic data. The extended kinematics include light spectra in multiple slitlets out to 3.5Re, and hundreds of planetary nebula velocities out to ≃7Re, thus allowing us to probe the dark matter content and orbital structure in the halo. We use Monte Carlo simulations to estimate confidence boundaries for the halo parameters, given our data and modelling set-up. We find that the true potential of the dark matter halo is recovered within ΔG (merit function) ≲ 26 (Δχ2 ≲ 59) at the 70 per cent confidence level (CL), and within ΔG ≲ 32 (Δχ2 ≲ 70) at the 90 per cent CL. These numbers are much larger than the usually assumed Δχ2 = 2.3 (4.6) for the 70 per cent (90 per cent) CL for two free parameters, perhaps case dependent, but calling into question the general validity of the standard assumptions used for halo and black hole mass determinations. The best-fitting models for NGC 4494 have a dark matter fraction of about 0.6 ± 0.1 at 5Re (70 per cent CL) and are embedded in a dark matter halo with circular velocity ˜200 km s-1. The total circular velocity curve (CVC) is approximately flat at vc = 220 km s-1 outside ˜0.5Re. The orbital anisotropy of the stars is moderately radial. These results are independent of the assumed inclination of the galaxy, and edge-on models are preferred. Comparing with the haloes of NGC 3379 and NGC 4697, whose velocity dispersion profiles also decrease rapidly from the centre outwards, the outer CVCs and dark matter haloes are quite similar. NGC 4494 shows a particularly high dark matter fraction inside ˜ 3Re, and a strong concentration of baryons in the centre.

  9. Retrieval of the Nitrous Oxide Profiles using the AIRS Data in China

    NASA Astrophysics Data System (ADS)

    Chen, L.; Ma, P.; Tao, J.; Li, X.; Zhang, Y.; Wang, Z.; Li, S.; Xiong, X.

    2014-12-01

    As an important greenhouse gas and ozone-depleting substance, the 100-year global warming potential of Nitrous Oxide (N2O) is almost 300 times higher than that of carbon dioxide. However, there are still large uncertainties about the quantitative N2O emission and its feedback to climate change due to the coarse ground-based network. This approach attempts to retrieve the N2O profiles from the Atmospheric InfraRed Sounder (AIRS) data. First, the sensitivity of atmospheric temperature and humidity profiles and surface parameters between two spectral absorption bands were simulated by using the radiative transfer model. Second, the eigenvector regression algorithm is used to construct a priori state. Third, an optimal estimate method was developed based on the band selection of N2O. Finally, we compared our retrieved AIRS profiles with HIPPO data, and analyzed the seasonal and annual N2O distribution in China from 2004 to 2013.

  10. Atmospheric profiles at the southern Pierre Auger Observatory and their relevance to air shower measurement

    SciTech Connect

    Keilhauer, B.; Bluemer, J.; Engel, R.; Gora, D.; Homola, P.; Klages, H.; Pekala, J.; Risse, M.; Unger, M.; Wilczynska, B.; Wilczynski, H.

    2005-07-01

    The dependence of atmospheric conditions on altitude and time have to be known at the site of an air shower experiment for accurate reconstruction of extensive air showers and their simulations. The height-profile of atmospheric depth is of particular interest as it enters directly into the reconstruction of longitudinal shower development and of the primary energy and mass of cosmic rays. For the southern part of the Auger Observatory, the atmosphere has been investigated in a number of campaigns with meteorological radio soundings and with continuous measurements of ground-based weather stations. Focusing on atmospheric depth and temperature profiles, temporal variations are described and monthly profiles are developed. Uncertainties of the monthly atmospheres that are currently applied in the Auger reconstruction are discussed.

  11. Monte Carlo simulation of an optical coherence Doppler tomograph signal: the effect of the concentration of particles in a flow on the reconstructed velocity profile

    SciTech Connect

    Bykov, A V; Kirillin, M Yu; Priezzhev, A V

    2005-02-28

    Model signals of an optical coherence Doppler tomograph (OCDT) are obtained by the Monte Carlo method from a flow of a light-scattering suspension of lipid vesicles (intralipid) at concentrations from 0.7% to 1.5% with an a priori specified parabolic velocity profile. The velocity profile parameters reconstructed from the OCDT signal and scattering orders of the photons contributing to the signal are studied as functions of the suspension concentration. It is shown that the maximum of the reconstructed velocity profile at high concentrations shifts with respect to the symmetry axis of the flow and its value decreases due to a greater contribution from multiply scattered photons. (papers devoted to the 250th anniversary of the moscow state university)

  12. AIR CONVECTION NOISE OF PENCIL-BEAM INTERFERMETER FOR LONG TRACE PROFILER.

    SciTech Connect

    YASHCHUK, V.V.; IRICK, S.C.; MACDOWELL, A.A.; MCKINNEY, W.R.; TAKACS, P.Z.

    2006-08-14

    In this work, we investigate the effect of air convection on laser-beam pointing noise essential for the long trace profiler (LTP). We describe this pointing error with noise power density (NPD) frequency distributions. It is shown that the NPD spectra due to air convection have a very characteristic form. In the range of frequencies from {approx}0.05 Hz to {approx}0.5 Hz, the spectra can be modeled with an inverse-power-law function. Depending on the intensity of air convection that is controlled with a resistive heater of 100 to 150 mW along a one-meter-long optical path, the power index lies between 2 and 3 at an overall rms noise of {approx}0.5 to 1 microradian. The efficiency of suppression of the convection noise by blowing air across the beam optical path is also discussed. Air-blowing leads to a white-noise-like spectrum. Air blowing was applied to the reference channel of an LTP allowing demonstration of the contribution of air convection noise to the LTP reference beam. The ability to change (with the blowing technique presented) the spectral characteristics of the beam pointing noise due to air convection allows one to investigate the contribution of the convection effect, and thus make corrections to the power spectral density spectra measured with the LTP.

  13. Air convection noise of pencil-beam interferometer for long trace profiler

    NASA Astrophysics Data System (ADS)

    Yashchuk, Valeriy V.; Irick, Steve C.; MacDowell, Alastair A.; McKinney, Wayne R.; Takacs, Peter Z.

    2006-08-01

    In this work, we investigate the effect of air convection on laser-beam pointing noise essential for the long trace profiler (LTP). We describe this pointing error with noise power density (NPD) frequency distributions. It is shown that the NPD spectra due to air convection have a very characteristic form. In the range of frequencies from ~0.05 Hz to ~0.5 Hz, the spectra can be modeled with an inverse-power-law function. Depending on the intensity of air convection that is controlled with a resistive heater of 100 to 150 mW along a one-meter-long optical path, the power index lies between 2 and 3 at an overall rms noise of ~0.5 to 1 microradian. The efficiency of suppression of the convection noise by blowing air across the beam optical path is also discussed. Air-blowing leads to a white-noise-like spectrum. Air blowing was applied to the reference channel of an LTP allowing demonstration of the contribution of air convection noise to the LTP reference beam. The ability to change (with the blowing technique presented) the spectral characteristics of the beam pointing noise due to air convection allows one to investigate the contribution of the convection effect, and thus make corrections to the power spectral density spectra measured with the LTP.

  14. Cellular automaton simulation of unidirectional pedestrians flow in a corridor to reproduce the unique velocity profile of Hagen-Poiseuille flow

    NASA Astrophysics Data System (ADS)

    Kaji, Masaru; Inohara, Takehiro

    2017-02-01

    In this study, we conduct simulations and compare results with experimental ones from previous work. It was reported that the velocity profile of pedestrians in a corridor had similar characteristics to that of an incompressible and Newtonian fluid in laminar flow, which is called Hagen-Poiseuille flow. To reproduce this pedestrian dynamics phenomenon, we hypothesized that the velocity profile is formed because of the intentions of pedestrians. We used the improved cellular automaton model integrating the multi-grid method and static floor field method to consider various rules regarding the characteristics of pedestrians, space, and algorithms. Simulation results show excellent agreement with results from previous study.

  15. A Comparison of the Red Green Blue Air Mass Imagery and Hyperspectral Infrared Retrieved Profiles

    NASA Technical Reports Server (NTRS)

    Berndt, E. B.; Folmer, Michael; Dunion, Jason

    2014-01-01

    The Red Green Blue (RGB) Air Mass imagery is derived from multiple channels or paired channel differences. Multiple channel products typically provide additional information than a single channel can provide alone. The RGB Air Mass imagery simplifies the interpretation of temperature and moisture characteristics of air masses surrounding synoptic and mesoscale features. Despite the ease of interpretation of multiple channel products, the combination of channels and channel differences means the resulting product does not represent a quantity or physical parameter such as brightness temperature in conventional single channel satellite imagery. Without a specific quantity to reference, forecasters are often confused as to what RGB products represent. Hyperspectral infrared retrieved profiles of temperature, moisture, and ozone can provide insight about the air mass represented on the RGB Air Mass product and provide confidence in the product and representation of air masses despite the lack of a quantity to reference for interpretation. This study focuses on RGB Air Mass analysis of Hurricane Sandy as it moved north along the U.S. East Coast, while transitioning to a hybrid extratropical storm. Soundings and total column ozone retrievals were analyzed using data from the Cross-track Infrared and Advanced Technology Microwave Sounder Suite (CrIMSS) on the Suomi National Polar Orbiting Partnership satellite and the Atmospheric Infrared Sounder (AIRS) on the National Aeronautics and Space Administration Aqua satellite along with dropsondes that were collected from National Oceanic and Atmospheric Administration and Air Force research aircraft. By comparing these datasets to the RGB Air Mass, it is possible to capture quantitative information that could help in analyzing the synoptic environment enough to diagnose the onset of extratropical transition. This was done by identifying any stratospheric air intrusions (SAIs) that existed in the vicinity of Sandy as the wind

  16. On the coefficients of small eddy and surface divergence models for the air-water gas transfer velocity

    NASA Astrophysics Data System (ADS)

    Wang, Binbin; Liao, Qian; Fillingham, Joseph H.; Bootsma, Harvey A.

    2015-03-01

    Recent studies suggested that under low to moderate wind conditions without bubble entraining wave breaking, the air-water gas transfer velocity k+ can be mechanistically parameterized by the near-surface turbulence, following the small eddy model (SEM). Field measurements have supported this model in a variety of environmental forcing systems. Alternatively, surface divergence model (SDM) has also been shown to predict the gas transfer velocity across the air-water interface in laboratory settings. However, the empirically determined model coefficients (α in SEM and c1 in SDM) scattered over a wide range. Here we present the first field measurement of the near-surface turbulence with a novel floating PIV system on Lake Michigan, which allows us to evaluate the SEM and SDM in situ in the natural environment. k+ was derived from the CO2 flux that was measured simultaneously with a floating gas chamber. Measured results indicate that α and c1 are not universal constants. Regression analysis showed that α˜log>(ɛ>) while the near-surface turbulence dissipation rate ɛ is approximately greater than 10-6 m2 s-3 according to data measured for this study as well as from other published results measured in similar environments or in laboratory settings. It also showed that α scales linearly with the turbulent Reynolds number. Similarly, coefficient c1 in the SDM was found to linearly scale with the Reynolds number. These findings suggest that larger eddies are also important parameters, and the dissipation rate in the SEM or the surface divergence β' in the SDM alone may not be adequate to determine k+ completely.

  17. Application of TiC reinforced Fe-based coatings by means of High Velocity Air Fuel Spraying

    NASA Astrophysics Data System (ADS)

    Bobzin, K.; Öte, M.; Knoch, M. A.; Liao, X.; Sommer, J.

    2017-03-01

    In the field of hydraulic applications, different development trends can cause problems for coatings currently used as wear and corrosion protection for piston rods. Aqueous hydraulic fluids and rising raw material prices necessitate the search for alternatives to conventional coatings like galvanic hard chrome or High Velocity Oxygen Fuel (HVOF)-sprayed WC/Co coatings. In a previous study, Fe/TiC coatings sprayed by a HVOF-process, were identified to be promising coating systems for wear and corrosion protection in hydraulic systems. In this feasibility study, the novel High Velocity Air Fuel (HVAF)-process, a modification of the HVOF-process, is investigated using the same feedstock material, which means the powder is not optimized for the HVAF-process. The asserted benefits of the HVAF-process are higher particle velocities and lower process temperatures, which can result in a lower porosity and oxidation of the coating. Further benefits of the HVAF process are claimed to be lower process costs and higher deposition rates. In this study, the focus is set on to the applicability of Fe/TiC coatings by HVAF in general. The Fe/TiC HVAF coating could be produced, successfully. The HVAF- and HVOF-coatings, produced with the same powder, were investigated using micro-hardness, porosity, wear and corrosion tests. A similar wear coefficient and micro-hardness for both processes could be achieved. Furthermore the propane/hydrogen proportion of the HVAF process and its influence on the coating thickness and the porosity was investigated.

  18. Measurement of Off-Body Velocity, Pressure, and Temperature in an Unseeded Supersonic Air Vortex by Stimulated Raman Scattering

    NASA Technical Reports Server (NTRS)

    Herring, Gregory C.

    2008-01-01

    A noninvasive optical method is used to make time-averaged (30 sec) off-body measurements in a supersonic airflow. Seeding of tracer particles is not required. One spatial component of velocity, static pressure, and static temperature are measured with stimulated Raman scattering. The three flow parameters are determined simultaneously from a common sample volume (0.3 by 0.3 by 15 mm) using concurrent measurements of the forward and backward scattered line shapes of a N2 vibrational Raman transition. The capability of this technique is illustrated with laboratory and large-scale wind tunnel testing that demonstrate 5-10% measurement uncertainties. Because the spatial resolution of the present work was improved to 1.5 cm (compared to 20 cm in previous work), it was possible to demonstrate a modest one-dimensional profiling of cross-flow velocity, pressure, and translational temperature through the low-density core of a stream-wise vortex (delta-wing model at Mach 2.8 in NASA Langley's Unitary Plan Wind Tunnel).

  19. 3D crustal seismic velocity model for the Gulf of Cadiz and adjacent areas (SW Iberia margin) based on seismic reflection and refraction profiles

    NASA Astrophysics Data System (ADS)

    Lozano, Lucía; Cantavella, Juan Vicente; Barco, Jaime; Carranza, Marta; Burforn, Elisa

    2016-04-01

    The Atlantic margin of the SW Iberian Peninsula and northern Morocco has been subject of study during the last 30 years. Many seismic reflection and refraction profiles have been carried out offshore, providing detailed information about the crustal structure of the main seafloor tectonic domains in the region, from the South Portuguese Zone and the Gulf of Cadiz to the Abyssal Plains and the Josephine Seamount. The interest to obtain a detailed and realistic velocity model for this area, integrating the available data from these studies, is clear, mainly to improve real-time earthquake hypocentral location and for tsunami and earthquake early warning. Since currently real-time seismic location tools allow the implementation of 3D velocity models, we aim to generate a full 3D crustal model. For this purpose we have reviewed more than 50 profiles obtained in different seismic surveys, from 1980 to 2008. Data from the most relevant and reliable 2D seismic velocity published profiles were retrieved. We first generated a Moho depth map of the studied area (latitude 32°N - 41°N and longitude 15°W - 5°W) by extracting Moho depths along each digitized profile with a 10 km spacing, and then interpolating this dataset using ordinary kriging method and generating the contour isodepth map. Then, a 3D crustal velocity model has been obtained. Selected vertical sections at different distances along each profile were considered to retrieve P-wave velocity values at each interface in order to reproduce the geometry and the velocity gradient within each layer. A double linear interpolation, both in distance and depth, with sampling rates of 10 km and 1 km respectively, was carried out to generate a (latitude, longitude, depth, velocity) matrix. This database of all the profiles was interpolated to obtain the P-wave velocity distribution map every kilometer of depth. The new 3D velocity model has been integrated in NonLinLoc location program to relocate several representative

  20. Correlation of turbulent burning velocities of ethanol-air, measured in a fan-stirred bomb up to 1.2 MPa

    SciTech Connect

    Bradley, D.; Lawes, M.; Mansour, M.S.

    2011-01-15

    The turbulent burning velocity is defined by the mass rate of burning and this also requires that the associated flame surface area should be defined. Previous measurements of the radial distribution of the mean reaction progress variable in turbulent explosion flames provide a basis for definitions of such surface areas for turbulent burning velocities. These inter-relationships. in general, are different from those for burner flames. Burning velocities are presented for a spherical flame surface, at which the mass of unburned gas inside it is equal to the mass of burned gas outside it. These can readily be transformed to burning velocities based on other surfaces. The measurements of the turbulent burning velocities presented are the mean from five different explosions, all under the same conditions. These cover a wide range of equivalence ratios, pressures and rms turbulent velocities for ethanol-air mixtures. Two techniques are employed, one based on measurements of high speed schlieren images, the other on pressure transducer measurements. There is good agreement between turbulent burning velocities measured by the two techniques. All the measurement are generalised in plots of burning velocity normalised by the effective unburned gas rms velocity as a function of the Karlovitz stretch factor for different strain rate Markstein numbers. For a given value of this stretch factor a decrease in Markstein number increases the normalised burning velocity. Comparisons are made with the findings of other workers. (author)

  1. Comparison of Profiling Microwave Radiometer, Aircraft, and Radiosonde Measurements From the Alliance Icing Research Study (AIRS)

    NASA Technical Reports Server (NTRS)

    Reehorst, Andrew L.

    2001-01-01

    Measurements from a profiling microwave radiometer are compared to measurements from a research aircraft and radiosondes. Data compared is temperature, water vapor, and liquid water profiles. Data was gathered at the Alliance Icing Research Study (AIRS) at Mirabel Airport outside Montreal, Canada during December 1999 and January 2000. All radiometer measurements were found to lose accuracy when the radome was wet. When the radome was not wetted, the radiometer was seen to indicate an inverted distribution of liquid water within a cloud. When the radiometer measurements were made at 15 deg. instead of the standard zenith, the measurements were less accurate.

  2. Effects of metabolic rate on thermal responses at different air velocities in -10 degrees C.

    PubMed

    Mäkinen, T T; Gavhed, D; Holmér, I; Rintamäki, H

    2001-04-01

    The effects of exercise intensity on thermoregulatory responses in cold (-10 degrees C) in a 0.2 (still air, NoWi), 1.0 (Wi1), and 5.0 (Wi5) m x s(-1) wind were studied. Eight young and healthy men, preconditioned in thermoneutral (+20 degrees C) environment for 60 min, walked for 60 min on the treadmill at 2.8 km/h with different combinations of wind and exercise intensity. Exercise level was adjusted by changing the inclination of the treadmill between 0 degrees (lower exercise intensity, metabolic rate 124 W x m(-2), LE) and 6 degrees (higher exercise intensity, metabolic rate 195 W x m(-2), HE). Due to exercise increased heat production and circulatory adjustments, the rectal temperature (T(re)), mean skin temperature (Tsk) and mean body temperature (Tb) were significantly higher at the end of HE in comparison to LE in NoWi and Wi1, and T(re) and Tb also in Wi5. Tsk and Tb were significantly decreased by 5.0 m x s(-1) wind in comparison to NoWi and Wi1. The higher exercise intensity was intense enough to diminish peripheral vasoconstriction and consequently the finger skin temperature was significantly higher at the end of HE in comparison to LE in NoWi and Wi1. Mean heat flux from the skin was unaffected by the exercise intensity. At LE oxygen consumption (VO2) was significantly higher in Wi5 than NoWi and Wi1. Heart rate was unaffected by the wind speed. The results suggest that, with studied exercise intensities, produced without changes in walking speed, the metabolic rate is not so important that it should be taken into consideration in the calculation of wind chill index.

  3. Shear Wave Velocity Profiles Determined from Surface Wave Measurements at Sites Affected by the August 15th, 2007 Earthquake in Peru

    NASA Astrophysics Data System (ADS)

    Rosenblad, B. L.; Bay, J. A.

    2008-05-01

    The shear wave velocity (Vs) profile of near-surface soils is a critical parameter for understanding recorded ground motions and predicting local site effects in an earthquake. In structural design, the Vs profile in the top 30 m is used to modify design response spectra to account for local soil effects. In addition, knowledge of the near- surface Vs profile at strong motion stations can be used to account for changes in frequency content and amplification caused by the local site conditions. Following the August 15th, 2007 earthquake in Peru, a field testing program was performed to measure Vs profiles in the top 20 to 30 m at twenty-two locations in the affected region. The measurements were performed primarily at the sites of damaged school buildings but were also performed at several strong motion station sites as well as a few locations where evidence of soil liquefaction was observed. Nineteen of the sites were located in the severely affected cities of Chincha, Ica, Pisco and Tambo de Mora, with the remaining three sites located in, Lima, Palpa and Paracus. The Vs profiles were determined from surface wave velocity measurements performed with an impact source. The objective of this paper is to present and discuss the range of Vs profile conditions encountered in the regions affected by the Pisco-Peru earthquake. In the city of Ica, the profiles generally exhibited gradually increasing velocities with depth, with velocities which rarely exceeded 400 m/s in the top 30 m. In contrast, the profiles measured in Pisco, often exhibited strong, shallow velocity contrasts with Vs increasing from less than 200 m/s at the surface to over 600 m/s at some sites. The profiles measured in Chincha generally fell in between the ranges measured in Ica and Pisco. Lastly, soil liquefaction was evident throughout Tambo de Mora on the coast of Peru. Measurements indicated very low shear wave velocities of 75 to 125 m/s in the top 4 m, which is consistent with the observed

  4. An Estimate of Solar Wind Velocity Profiles in a Coronal Hole and a Coronal Streamer Area (6-40 R(radius symbol)

    NASA Technical Reports Server (NTRS)

    Patzold, M.; Tsurutani, B. T.; Bird, M. K.

    1995-01-01

    Total electron content data obtained from the Ulysses Solar Corona Experiment (SCE) in 1991 were used to select two data sets, one associated with a coronal hole and the other with coronal streamer crossings. (This is largely equatorial data shortly after solar maximum.) The solar wind velocity profile is estimated for these areas.

  5. Improving 7-Day Forecast Skill by Assimilation of Retrieved AIRS Temperature Profiles

    NASA Technical Reports Server (NTRS)

    Susskind, Joel; Rosenberg, Bob

    2016-01-01

    We conducted a new set of Data Assimilation Experiments covering the period January 1 to February 29, 2016 using the GEOS-5 DAS. Our experiments assimilate all data used operationally by GMAO (Control) with some modifications. Significant improvement in Global and Southern Hemisphere Extra-tropical 7-day forecast skill was obtained when: We assimilated AIRS Quality Controlled temperature profiles in place of observed AIRS radiances, and also did not assimilate CrISATMS radiances, nor did we assimilate radiosonde temperature profiles or aircraft temperatures. This new methodology did not improve or degrade 7-day Northern Hemispheric Extra-tropical forecast skill. We are conducting experiments aimed at further improving of Northern Hemisphere Extra-tropical forecast skill.

  6. Flow velocity profiling using acoustic time of flight flow metering based on wide band signals and adaptive beam-forming techniques

    NASA Astrophysics Data System (ADS)

    Murgan, I.; Candel, I.; Ioana, C.; Digulescu, A.; Bunea, F.; Ciocan, G. D.; Anghel, A.; Vasile, G.

    2016-11-01

    In this paper, we present a novel approach to non-intrusive flow velocity profiling technique using multi-element sensor array and wide-band signal's processing methods. Conventional techniques for the measurements of the flow velocity profiles are usually based on intrusive instruments (current meters, acoustic Doppler profilers, Pitot tubes, etc.) that take punctual velocity readings. Although very efficient, these choices are limited in terms of practical cases of applications especially when non-intrusive measurements techniques are required and/or a spatial accuracy of the velocity profiling is required This is due to factors related to hydraulic machinery down time, the often long time duration needed to explore the entire section area, the frequent cumbersome number of devices that needs to be handled simultaneously, or the impossibility to perform intrusive tests. In the case of non-intrusive flow profiling methods based on acoustic techniques, previous methods concentrated on using a large number of acoustic transducers placed around the measured section. Although feasible, this approach presents several major drawbacks such as a complicated signal timing, transmission, acquisition and recording system, resulting in a relative high cost of operation. In addition, because of the geometrical constraints, a desired number of sensors may not be installed. Recent results in acoustic flow metering based on wide band signals and adaptive beamforming proved that it is possible to achieve flow velocity profiles using less acoustic transducers. In a normal acoustic time of flight path the transducers are both emitters and receivers, sequentially changing their roles. In the new configuration, proposed in this paper, two new receivers are added on each side. Since the beam angles of each acoustic transducer are wide enough the newly added transducers can receive the transmitted signals and additional time of flight estimation can be done. Thus, several flow

  7. Performance of greenhouse gas profiling by infrared-laser and microwave occultation in cloudy air

    NASA Astrophysics Data System (ADS)

    Proschek, V.; Kirchengast, G.; Emde, C.; Schweitzer, S.

    2012-12-01

    ACCURATE is a proposed future satellite mission enabling simultaneous measurements of greenhouse gases (GHGs), wind and thermodynamic variables from Low Earth Orbit (LEO). The measurement principle is a combination of LEO-LEO infrared-laser occultation (LIO) and microwave occultation (LMO), the LMIO method, where the LIO signals are very sensitive to clouds. The GHG retrieval will therefore be strongly influenced by clouds in parts of the troposphere. The IR-laser signals, at wavelengths within 2--2.5μ m, are chosen to measure six GHGs (H2O, CO2, CH4, N2O, O3, CO; incl.~key isotopes 13CO2, C18OO, HDO). The LMO signals enable to co-measure the thermodynamic variables. In this presentation we introduce the algorithm to retrieve GHG profiles under cloudy-air conditions by using quasi-realistic forward simulations, including also influence of Rayleigh scattering, scintillations and aerosols. Data from CALIPSO--Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations--with highest vertical resolution of about 60 m and horizontal resolution of about 330 m were used for simulation of clouds. The IR-laser signals consist for each GHG of a GHG-sensitive and a close-by reference signal. The key process, ``differencing'' of these two signals, removes the atmospheric ``broadband'' effects, resulting in a pure GHG transmission profile. Very thin ice clouds, like sub-visible cirrus, are fairly transparent to the IR-laser signals, thicker and liquid water clouds block the signals. The reference signal is used to produce a cloud layering profile from zero to blocking clouds and is smoothed in a preprocess to suppress scintillations. Sufficiently small gaps, of width <2 km in the cloud layering profile, are found to enable a decent retrieval of entire GHG profiles over the UTLS under broken cloudiness and are therefore bridged by interpolation. Otherwise in case of essentially continuous cloudiness the profiles are found to terminate at cloud top level. The accuracy of

  8. Statistical temperature profile retrievals in clear-air using passive 118-GHz O2 observations

    NASA Technical Reports Server (NTRS)

    Gasiewski, A. J.; Johnson, J. T.

    1993-01-01

    The clean-air temperature profile accuracy yielded by a localized linear statistical retrieval operator applied to passive aircraft-based 118-GHz spectra is demonstrated. A comparison of the statistically and physically derived correlation coefficients of antenna temperature and kinetic temperature furnishes a physical justification of the statistical retrieval technique. The atmospheric temperature mean and covariance significantly depend on such geophysical parameters as latitude, longitude, local season, and time, as well as the prevailing meteorological state and orographic effects.

  9. Heat Exchange with Air and Temperature Profile of a Moving Oversize Tire

    NASA Astrophysics Data System (ADS)

    Grinchuk, P. S.; Fisenko, S. P.

    2016-11-01

    A one-dimensional mathematical model of heat transfer in a tire with account for the deformation energy dissipation and heat exchange of a moving tire with air has been developed. The mean temperature profiles are calculated and transition to a stationary thermal regime is considered. The influence of the rate of energy dissipation and of effective thermal conductivity of rubber on the temperature field is investigated quantitatively.

  10. Responses of atmospheric electric field and air-earth current to variations of conductivity profiles

    NASA Astrophysics Data System (ADS)

    Makino, M.; Ogawa, T.

    1984-05-01

    A global circuit model is constructed to study responses of air-earth current and electric field to a variation of atmospheric electrical conductivity profile. The model includes the orography and the global distribution of thunderstorm generators. The conductivity varies with latitude and exponentially with altitude. The thunderstorm cloud is assumed to be a current generator with a positive source at the top and a negative one at the bottom. The UT diurnal variations of the global current and the ionospheric potential are evaluated considering the local-time dependence of thunderstorm activity. The global distribution of the electric field and the air-earth current are affected by the orography and latitudinal effects. Assuming a variation of conductivity profile, responses of atmospheric electrical parameters are investigated. The nonuniform decrement of the conductivity with altitude increases both the electric field and the air-earth current. The result suggests a possibility that the increment of the electric field and the air-earth current after a solar flare may be caused by this scheme, due to Forbush decrease.

  11. A one-dimensional numerical model for predicting pressure and velocity oscillations of a compressed air-pocket in a vertical shaft

    NASA Astrophysics Data System (ADS)

    Choi, Y.; Leon, A.; Apte, S.

    2015-12-01

    The presence of pressurized air pockets in combined sewer systems is argued to produce geyser flows, which is an oscillating jetting of a mixture of gas-liquid flows through vertical shafts. A 1D numerical model is developed for predicting pressure and velocity oscillations of a compressed air-pocket in a vertical shaft which in turn attempts to simulate geyser like flows. The vertical shaft is closed at the bottom and open to ambient pressure at the top. Initially, the lower section of the vertical shaft is filled with compressed air and the upper section with water. The interaction between the pressurized air pocket and the water column in the vertical shaft exhibits an oscillatory motion of the water column that decays over time. The model accounts for steady and unsteady friction to estimate the energy dissipation. The model also includes the falling flow of water around the external perimeter of the pressurized air pocket by assuming that any expansion in the pressurized air pocket would result in the falling volume of water. The acceleration of air-water interface is predicted through a force balance between the pressurized air pocket and the water column combined with the Method of Characteristics that resolves pressure and velocity within the water column. The expansion and compression of the pressurized air pocket is assumed to follow either isothermal process or adiabatic process. Results for both assumptions; isothermal and adiabatic processes, are presented. The performance of the developed 1D numerical model is compared with that of a commercial 3D CFD model. Overall, a good agreement between both models is obtained for pressure and velocity oscillations. The paper will also present a sensitivity analysis of the 3D CFD model.

  12. The impact of AIRS atmospheric temperature and moisture profiles on hurricane forecasts: Ike (2008) and Irene (2011)

    NASA Astrophysics Data System (ADS)

    Zheng, Jing; Li, Jun; Schmit, Timothy J.; Li, Jinlong; Liu, Zhiquan

    2015-03-01

    Atmospheric InfraRed Sounder (AIRS) measurements are a valuable supplement to current observational data, especially over the oceans where conventional data are sparse. In this study, two types of AIRS-retrieved temperature and moisture profiles, the AIRS Science Team product (SciSup) and the single field-of-view (SFOV) research product, were evaluated with European Centre for Medium-Range Weather Forecasts (ECMWF) analysis data over the Atlantic Ocean during Hurricane Ike (2008) and Hurricane Irene (2011). The evaluation results showed that both types of AIRS profiles agreed well with the ECMWF analysis, especially between 200 hPa and 700 hPa. The average standard deviation of both temperature profiles was approximately 1 K under 200 hPa, where the mean AIRS temperature profile from the AIRS SciSup retrievals was slightly colder than that from the AIRS SFOV retrievals. The mean SciSup moisture profile was slightly drier than that from the SFOV in the mid troposphere. A series of data assimilation and forecast experiments was then conducted with the Advanced Research version of the Weather Research and Forecasting (WRF) model and its three-dimensional variational (3DVAR) data assimilation system for hurricanes Ike and Irene. The results showed an improvement in the hurricane track due to the assimilation of AIRS clear-sky temperature profiles in the hurricane environment. In terms of total precipitable water and rainfall forecasts, the hurricane moisture environment was found to be affected by the AIRS sounding assimilation. Meanwhile, improving hurricane intensity forecasts through assimilating AIRS profiles remains a challenge for further study.

  13. Study on measurement of the coal powder concentration in pneumatic pipes of a boiler with relationship between air velocity and pressure drop

    SciTech Connect

    Pan, W.; Shen, F.; Lin, W.; Chen, L.; Zhang, D.; Wang, Q.; Ke, J.; Quan, W.

    1999-07-01

    According to the theoretical relationship between air velocity and pressure drop in different solid-air mass flow in vertical pipes with the condition of upward air-solid flowing, the experimental research on measuring the coal powder concentration is directed against the pneumatic pipes of a boiler's combustion system in the energy industry. Through analyzing the experimental results, a mathematical model for measuring the coal powder concentration in pneumatic pipes is obtained. Then, the error analysis is done, and the method of on-line measurement and its function are provided.

  14. Organochlorine pesticides in soils and air of southern Mexico: Chemical profiles and potential for soil emissions

    NASA Astrophysics Data System (ADS)

    Wong, Fiona; Alegria, Henry A.; Jantunen, Liisa M.; Bidleman, Terry F.; Salvador-Figueroa, Miguel; Gold-Bouchot, Gerardo; Ceja-Moreno, Victor; Waliszewski, Stefan M.; Infanzon, Raul

    The extent of organochlorine pesticides (OCs) contamination in southern Mexico was investigated in this study. Biweekly air samplings were carried out in two sites in the state of Chiapas (during 2002-2003), and one in each state of Veracruz and Tabasco (during 2003-2004). Corresponding to the air sampling locations, soil samples were also collected to gauge the soil-air exchange of OCs in the region. ∑DDTs in soils ranged from 0.057 to 360 ng g -1 whereas those in air ranged from 240 to 2400 pg m -3. DDT and metabolite DDE were expressed as fractional values, FDDTe = p, p'-DDT/( p, p'-DDT + p, p'-DDE) and FDDTo = p,p'-DDT/( p,p'-DDT + o,p'-DDT). FDDTe in soils ranged from 0.30 to 0.69 while those in air ranged from 0.45 to 0.84. FDDTe in air at a farm in Chiapas (0.84) was closer to that of technical DDT (0.95) which is suggestive of fresh DDT input. Enantiomer fractions (EF) of o,p'-DDT in air were racemic at all locations (0.500-0.504). However, nonracemic o,p'-DDT was seen in the soils (EFs = 0.456-0.647). Fugacities of OCs in soil ( fs) and air ( fa) were calculated, and the fugacity fraction, ff = fs/( fs + fa) of DDTs ranged from 0.013 to 0.97 which indicated a mix of net deposition ( ff < 0.5) and volatilization ( ff > 0.5) from soil among the sites. It is suggested that DDTs in Mexico air are due to a combination of ongoing regional usage and re-emission of old DDT residues from soils. Total toxaphene in soils ranged from 0.066 to 69 ng g -1 while levels in air ranged from 6.2 to 230 pg m -3. Chromatographic profiles of toxaphenes in both air and soil showed depletion of Parlar congeners 39 and 42. Fugacity fractions of toxaphene were within the equilibrium range or above the upper equilibrium threshold boundary. These findings suggested that soil emission of old residues is the main source of toxaphenes to the atmosphere. Results from this study provide baseline data for establishing a long-term OC monitoring program in Mexico.

  15. Development and evaluation of a profile negotiation process for integrating aircraft and air traffic control automation

    NASA Technical Reports Server (NTRS)

    Green, Steven M.; Denbraven, Wim; Williams, David H.

    1993-01-01

    The development and evaluation of the profile negotiation process (PNP), an interactive process between an aircraft and air traffic control (ATC) that integrates airborne and ground-based automation capabilities to determine conflict-free trajectories that are as close to an aircraft's preference as possible, are described. The PNP was evaluated in a real-time simulation experiment conducted jointly by NASA's Ames and Langley Research Centers. The Ames Center/TRACON Automation System (CTAS) was used to support the ATC environment, and the Langley Transport Systems Research Vehicle (TSRV) piloted cab was used to simulate a 4D Flight Management System (FMS) capable aircraft. Both systems were connected in real time by way of voice and data lines; digital datalink communications capability was developed and evaluated as a means of supporting the air/ground exchange of trajectory data. The controllers were able to consistently and effectively negotiate nominally conflict-free vertical profiles with the 4D-equipped aircraft. The actual profiles flown were substantially closer to the aircraft's preference than would have been possible without the PNP. However, there was a strong consensus among the pilots and controllers that the level of automation of the PNP should be increased to make the process more transparent. The experiment demonstrated the importance of an aircraft's ability to accurately execute a negotiated profile as well as the need for digital datalink to support advanced air/ground data communications. The concept of trajectory space is proposed as a comprehensive approach for coupling the processes of trajectory planning and tracking to allow maximum pilot discretion in meeting ATC constraints.

  16. Computational simulation of temperature and velocity distribution in human upper respiratory airway during inhalation of hot air.

    PubMed

    Goodarzi-Ardakani, V; Taeibi-Rahni, M; Salimi, M R; Ahmadi, G

    2016-03-01

    The present study provides an accurate simulation of velocity and temperature distributions of inhalation thermal injury in a human upper airway, including vestibule, nasal cavity, paranasal sinuses, nasopharynx, oropharynx, larynx, and upper part of main bronchus. To this end, a series of CT scan images, taken from an adult woman, was used to construct a three dimensional model. The airway walls temperature was adjusted according to existing in vivo temperature measurements. Also, in order to cover all breathing activities, five different breathing flow rates (10, 15, 20, 30, and 40 l/min) and different ambient air temperatures (100, 200, 300, 400, and 500 °C) were studied. Different flow regimes, including laminar, transitional, and turbulence were considered and the simulations were validated using reliable experimental data. The results show that nostrils, vestibule, and nasal cavity are damaged more than other part of airway. Finally, In order to obtain the heat flux through the walls, correlations for Nusselt number for each individual parts of airway (vestibule, main upper airway, nasopharynx etc.,) are proposed.

  17. Laminar burning velocities of lean hydrogen-air mixtures at pressures up to 1.0 MPa

    SciTech Connect

    Bradley, D.; Lawes, M.; Liu, Kexin; Woolley, R.; Verhelst, S.

    2007-04-15

    Values of laminar burning velocity, u{sub l}, and the associated strain rate Markstein number, Ma{sub sr}, of H{sub 2}-air mixtures have been obtained from measurements of flame speeds in a spherical explosion bomb with central ignition. Pressures ranged from 0.1 to 1.0 MPa, with values of equivalence ratio between 0.3 and 1.0. Many of the flames soon became unstable, with an accelerating flame speed, due to Darrieus-Landau and thermodiffusive instabilities. This effect increased with pressure. The flame wrinkling arising from the instabilities enhanced the flame speed. A method is described for allowing for this effect, based on measurements of the flame radii at which the instabilities increased the flame speed. This enabled u{sub l} and Ma{sub sr} to be obtained, devoid of the effects of instabilities. With increasing pressure, the time interval between the end of the ignition spark and the onset of flame instability, during which stable stretched flame propagation occurred, became increasingly small and very high camera speeds were necessary for accurate measurement. Eventually this time interval became so short that first Ma{sub sr} and then u{sub l} could not be measured. Such flame instabilities throw into question the utility of u{sub l} for high pressure, very unstable, flames. The measured values of u{sub l} are compared with those predicted by detailed chemical kinetic models of one-dimensional flames. (author)

  18. Impact of seasonality and air pollutants on carotid-femoral pulse wave velocity and wave reflection in hypertensive patients

    PubMed Central

    Stea, Francesco; Massetti, Luciano; Taddei, Stefano; Ghiadoni, Lorenzo; Modesti, Pietro Amedeo

    2017-01-01

    Objective The effects of seasonality on blood pressure (BP) and cardiovascular (CV) events are well established, while the influence of seasonality and other environmental factors on arterial stiffness and wave reflection has never been analyzed. This study evaluated whether seasonality (daily number of hours of light) and acute variations in outdoor temperature and air pollutants may affect carotid-femoral pulse wave velocity (PWV) and pressure augmentation. Design and method 731 hypertensive patients (30–88 years, 417 treated) were enrolled in a cross-sectional study during a 5-year period. PWV, central BP, Augmentation Index (AIx) and Augmentation Pressure (AP) were measured in a temperature-controlled (22–24°C) room. Data of the local office of the National Climatic Data Observatory were used to estimate meteorological conditions and air pollutants (PM10, O3, CO, N2O) exposure on the same day. Results PWV (mean value 8.5±1.8 m/s) was related to age (r = 0.467, p<0.001), body mass index (r = 0.132, p<0.001), central systolic (r = 0.414, p<0.001) and diastolic BP (r = 0.093, p = 0.013), daylight hours (r = -0.176, p<0.001), mean outdoor temperature (r = -0.082, p = 0.027), O3 (r = -0.135, p<0.001), CO (r = 0.096, p = 0.012), N2O (r = 0.087, p = 0.022). In multiple linear regression analysis, adjusted for confounders, PWV remained independently associated only with daylight hours (β = -0.170; 95% CI: -0.273 to -0.067, p = 0.001). No significant correlation was found between pressure augmentation and daylight hours, mean temperature or air pollutants. The relationship was stronger in untreated patients and women. Furthermore, a positive, independent association between O3 levels and PWV emerged in untreated patients (β: 0.018; p = 0.029; CI: 0.002 to 0.034) and in women (β: 0.027; p = 0.004; CI: 0.009 to 0.045). Conclusions PWV showed a marked seasonality in hypertensive patients. Environmental O3 levels may acutely reduce arterial stiffness in

  19. Nominal Height-of-Burst for a Near-Earth Asteroid: Profiles of Radiation-deposition and change-in-velocity

    NASA Astrophysics Data System (ADS)

    Ferguson, J.; Gisler, G. R.; Plesko, C. S.; Weaver, R.

    2015-12-01

    In this work we profile the radiation deposition, and the velocity change, for a hazardous near-earth asteroid using a stand-off radiation source delivered at various heights-of-burst. For the radiation deposition, we compare results from analytic calculations, a particle transport code, and an adaptive-mesh radiation-hydrodynamic code; the change in velocity is computed using an adaptive-mesh radiation-hydrodynamic code. The nominal heights-of-burst will be compared, and applied to the potential deflection of the asteroid 101955 Bennu.

  20. Megha-Tropiques/SAPHIR measurements of humidity profiles: validation with AIRS and global radiosonde network

    NASA Astrophysics Data System (ADS)

    Subrahmanyam, K. V.; Kumar, K. K.

    2013-12-01

    The vertical profiles of humidity measured by SAPHIR (Sondeur Atmospherique du Profil d' Humidité Intropicale par Radiométrie) on-board Megha-Tropiques satellite are validated using Atmosphere Infrared Sounder (AIRS) and ground based radiosonde observations during July-September 2012. SAPHIR provides humidity profiles at six pressure layers viz., 1000-850 (level 1), 850-700 (level 2), 700-550 (level 3), 550-400 (level 4) 400-250 (level 5) and 250-100(level 6) hPa. Segregated AIRS observations over land and oceanic regions are used to assess the performance of SAPHIR quantitatively. The regression analysis over oceanic region (125° W-180° W; 30° S-30° N) reveal that the SAPHIR measurements agrees very well with the AIRS measurements at levels 3, 4, 5 and 6 with correlation coefficients 0.79, 0.88, 0.87 and 0.78 respectively. However, at level 6 SAPHIR seems to be systematically underestimating the AIRS measurements. At level 2, the agreement is reasonably good with correlation coefficient of 0.52 and at level 1 the agreement is very poor with correlation coefficient 0.17. The regression analysis over land region (10° W-30° E; 8° N-30° N) revealed an excellent correlation between AIRS and SAPHIR at all the six levels with 0.80, 0.78, 0.84, 0.84, 0.86 and 0.65 respectively. However, again at levels 5 and 6, SAPHIR seems to be underestimating the AIRS measurements. After carrying out the quantitative comparison between SAPHIR and AIRS separately over land and ocean, the ground based global radiosonde network observations of humidity profiles over three distinct geographical locations (East Asia, tropical belt of South and North America and South Pacific) are then used to further validate the SAPHIR observations as AIRS has its own limitations. The SAPHIR observations within a radius of 50 km around the radiosonde stations are averaged and then the regression analysis is carried out at the first five levels of SAPHIR. The comparison is not carried out at sixth

  1. Evaluation of the Impact of Atmospheric Infrared Sounder (AIRS) Radiance and Profile Data Assimilation in Partly Cloudy Regions

    NASA Technical Reports Server (NTRS)

    Zavodsky, Bradley; Srikishen, Jayanthi; Jedlovec, Gary

    2013-01-01

    Improvements to global and regional numerical weather prediction have been demonstrated through assimilation of data from NASA s Atmospheric Infrared Sounder (AIRS). Current operational data assimilation systems use AIRS radiances, but impact on regional forecasts has been much smaller than for global forecasts. Retrieved profiles from AIRS contain much of the information that is contained in the radiances and may be able to reveal reasons for this reduced impact. Assimilating AIRS retrieved profiles in an identical analysis configuration to the radiances, tracking the quantity and quality of the assimilated data in each technique, and examining analysis increments and forecast impact from each data type can yield clues as to the reasons for the reduced impact. By doing this with regional scale models individual synoptic features (and the impact of AIRS on these features) can be more easily tracked. This project examines the assimilation of hyperspectral sounder data used in operational numerical weather prediction by comparing operational techniques used for AIRS radiances and research techniques used for AIRS retrieved profiles. Parallel versions of a configuration of the Weather Research and Forecasting (WRF) model with Gridpoint Statistical Interpolation (GSI) are run to examine the impact AIRS radiances and retrieved profiles. Statistical evaluation of 6 weeks of forecast runs will be compared along with preliminary results of in-depth investigations for select case comparing the analysis increments in partly cloudy regions and short-term forecast impacts.

  2. Development of a High Resolution X-Ray Imaging Crystal Spectrometer for Measurement of Ion-Temperature and Rotation-Velocity Profiles in Fusion Energy Research Plasmas

    SciTech Connect

    Hill, K W; Broennimann, Ch; Eikenberry, E F; Ince-Cushman, A; Lee, S G; Rice, J E; Scott, S

    2008-02-27

    A new imaging high resolution x-ray crystal spectrometer (XCS) has been developed to measure continuous profiles of ion temperature and rotation velocity in fusion plasmas. Following proof-of-principle tests on the Alcator C-Mod tokamak and the NSTX spherical tokamak, and successful testing of a new silicon, pixilated detector with 1MHz count rate capability per pixel, an imaging XCS is being designed to measure full profiles of Ti and vφ on C-Mod. The imaging XCS design has also been adopted for ITER. Ion-temperature uncertainty and minimum measurable rotation velocity are calculated for the C-Mod spectrometer. The affects of x-ray and nuclear-radiation background on the measurement uncertainties are calculated to predict performance on ITER.

  3. An Experimental Investigation Into the Temperature Profile of a Compliant Foil Air Bearing

    NASA Technical Reports Server (NTRS)

    Radil, Kevin; Zeszotek, Michelle

    2004-01-01

    A series of tests was performed to determine the internal temperature profile in a compliant bump-type foil journal air bearing operating at room temperature under various speeds and load conditions. The temperature profile was collected by instrumenting a foil bearing with nine, type K thermocouples arranged in the center and along the bearing s edges in order to measure local temperatures and estimate thermal gradients in the axial and circumferential directions. To facilitate the measurement of maximum temperatures from viscous shearing in the air film, the thermocouples were tack welded to the backside of the bumps that were in direct contact with the top foil. The mating journal was coated with a high temperature solid lubricant that, together with the bearing, underwent high temperature start-stop cycles to produce a smooth, steady-state run-in surface. Tests were conducted at speeds from 20 to 50 krpm and loads ranging from 9 to 222 N. The results indicate that, over the conditions tested, both journal rotational speed and radial load are responsible for heat generation with speed playing a more significant role in the magnitude of the temperatures. The temperature distribution was nearly symmetric about the bearing center at 20 and 30 krpm but became slightly skewed toward one side at 40 and 50 krpm. Surprisingly, the maximum temperatures did not occur at the bearing edge where the minimum film thickness is expected but rather in the middle of the bearing where analytical investigations have predicted the air film to be much thicker. Thermal gradients were common during testing and were strongest in the axial direction from the middle of the bearing to its edges, reaching 3.78 8C/mm. The temperature profile indicated the circumferential thermal gradients were negligible.

  4. Bias Correction for Assimilation of Retrieved AIRS Profiles of Temperature and Humidity

    NASA Technical Reports Server (NTRS)

    Blankenship, Clay; Zavodsky, Brad; Blackwell, William

    2014-01-01

    Atmospheric Infrared Sounder (AIRS) is a hyperspectral radiometer aboard NASA's Aqua satellite designed to measure atmospheric profiles of temperature and humidity. AIRS retrievals are assimilated into the Weather Research and Forecasting (WRF) model over the North Pacific for some cases involving "atmospheric rivers". These events bring a large flux of water vapor to the west coast of North America and often lead to extreme precipitation in the coastal mountain ranges. An advantage of assimilating retrievals rather than radiances is that information in partly cloudy fields of view can be used. Two different Level 2 AIRS retrieval products are compared: the Version 6 AIRS Science Team standard retrievals and a neural net retrieval from MIT. Before assimilation, a bias correction is applied to adjust each layer of retrieved temperature and humidity so the layer mean values agree with a short-term model climatology. WRF runs assimilating each of the products are compared against each other and against a control run with no assimilation. This paper will describe the bias correction technique and results from forecasts evaluated by validation against a Total Precipitable Water (TPW) product from CIRA and against Global Forecast System (GFS) analyses.

  5. Bias Correction for Assimilation of Retrieved AIRS Profiles of Temperature and Humidity

    NASA Technical Reports Server (NTRS)

    Blakenship, Clay; Zavodsky, Bradley; Blackwell, William

    2014-01-01

    The Atmospheric Infrared Sounder (AIRS) is a hyperspectral radiometer aboard NASA's Aqua satellite designed to measure atmospheric profiles of temperature and humidity. AIRS retrievals are assimilated into the Weather Research and Forecasting (WRF) model over the North Pacific for some cases involving "atmospheric rivers". These events bring a large flux of water vapor to the west coast of North America and often lead to extreme precipitation in the coastal mountain ranges. An advantage of assimilating retrievals rather than radiances is that information in partly cloudy fields of view can be used. Two different Level 2 AIRS retrieval products are compared: the Version 6 AIRS Science Team standard retrievals and a neural net retrieval from MIT. Before assimilation, a bias correction is applied to adjust each layer of retrieved temperature and humidity so the layer mean values agree with a short-term model climatology. WRF runs assimilating each of the products are compared against each other and against a control run with no assimilation. Forecasts are against ERA reanalyses.

  6. Power Stroke Angular Velocity Profiles of Archaeal A-ATP Synthase Versus Thermophilic and Mesophilic F-ATP Synthase Molecular Motors.

    PubMed

    Sielaff, Hendrik; Martin, James; Singh, Dhirendra; Biuković, Goran; Grüber, Gerhard; Frasch, Wayne D

    2016-12-02

    The angular velocities of ATPase-dependent power strokes as a function of the rotational position for the A-type molecular motor A3B3DF, from the Methanosarcina mazei Gö1 A-ATP synthase, and the thermophilic motor α3β3γ, from Geobacillus stearothermophilus (formerly known as Bacillus PS3) F-ATP synthase, are resolved at 5 μs resolution for the first time. Unexpectedly, the angular velocity profile of the A-type was closely similar in the angular positions of accelerations and decelerations to the profiles of the evolutionarily distant F-type motors of thermophilic and mesophilic origins, and they differ only in the magnitude of their velocities. M. mazei A3B3DF power strokes occurred in 120° steps at saturating ATP concentrations like the F-type motors. However, because ATP-binding dwells did not interrupt the 120° steps at limiting ATP, ATP binding to A3B3DF must occur during the catalytic dwell. Elevated concentrations of ADP did not increase dwells occurring 40° after the catalytic dwell. In F-type motors, elevated ADP induces dwells 40° after the catalytic dwell and slows the overall velocity. The similarities in these power stroke profiles are consistent with a common rotational mechanism for A-type and F-type rotary motors, in which the angular velocity is limited by the rotary position at which ATP binding occurs and by the drag imposed on the axle as it rotates within the ring of stator subunits.

  7. The effect of wind velocity, air temperature and humidity on NH 3 and SO 2 transfer into bean leaves ( phaseolus vulgaris L.)

    NASA Astrophysics Data System (ADS)

    van Hove, L. W. A.; Vredenberg, W. J.; Adema, E. H.

    The influence of wind velocity, air temperature and vapour pressure deficit of the air (VPD) on NH 3 and SO 2 transfer into bean leaves ( Phaseolus vulgaris L.) was examined using a leaf chamber. The measurements suggested a transition in the properties of the leaf boundary layer at a wind velocity of 0.3-0.4 ms -1 which corresponds to a Recrit value of about 2000. At higher wind velocities the leaf boundary layer resistance ( rb) was 1.5-2 times lower than can be calculated from the theory. Nevertheless, the assessed relationships between rb and wind velocity appeared to be similar to the theoretical derived relationship for rb. The NH 3 flux and in particular the SO 2 flux into the leaf strongly increased at a VPD decline. The increase of the NH 3 flux could be attributed to an increase of the stomatal conductance ( gs). However, the increase of the SO 2 flux could only partly be explained by an increase of gs. An apparent additional uptake was also observed for the NH 3 uptake at a low temperature and VPD. The SO 2 flux was also influenced by air temperature which could be explained by a temperature effect on gs. The results suggest that calculation of the NH 3 and SO 2 flux using data of gs gives a serious understimation of the real flux of these gases into leaves at a low temperature and VPD.

  8. An analytic study on the effect of alginate on the velocity profiles of blood in rectangular microchannels using microparticle image velocimetry.

    PubMed

    Pitts, Katie L; Fenech, Marianne

    2013-01-01

    It is desired to understand the effect of alginic acid sodium salt from brown algae (alginate) as a viscosity modifier on the behavior of blood in vitro using a micro-particle image velocimetry (µPIV) system. The effect of alginate on the shape of the velocity profile, the flow rate and the maximum velocity achieved in rectangular microchannels channels are measured. The channels were constructed of polydimethylsiloxane (PDMS), a biocompatible silicone. Porcine blood cells suspended in saline was used as the working fluid at twenty percent hematocrit (H = 20). While alginate was only found to have minimal effect on the maximum velocity and the flow rate achieved, it was found to significantly affect the shear rate at the wall by between eight to a hundred percent.

  9. Evolution of blast wave profiles in simulated air blasts: experiment and computational modeling

    NASA Astrophysics Data System (ADS)

    Chandra, N.; Ganpule, S.; Kleinschmit, N. N.; Feng, R.; Holmberg, A. D.; Sundaramurthy, A.; Selvan, V.; Alai, A.

    2012-09-01

    Shock tubes have been extensively used in the study of blast traumatic brain injury due to increased incidence of blast-induced neurotrauma in Iraq and Afghanistan conflicts. One of the important aspects in these studies is how to best replicate the field conditions in the laboratory which relies on reproducing blast wave profiles. Evolution of the blast wave profiles along the length of the compression-driven air shock tube is studied using experiments and numerical simulations with emphasis on the shape and magnitude of pressure time profiles. In order to measure dynamic pressures of the blast, a series of sensors are mounted on a cylindrical specimen normal to the flow direction. Our results indicate that the blast wave loading is significantly different for locations inside and outside of the shock tube. Pressure profiles inside the shock tube follow the Friedlander waveform fairly well. Upon approaching exit of the shock tube, an expansion wave released from the shock tube edges significantly degrades the pressure profiles. For tests outside the shock tube, peak pressure and total impulse reduce drastically as we move away from the exit and majority of loading is in the form of subsonic jet wind. In addition, the planarity of the blast wave degrades as blast wave evolves three dimensionally. Numerical results visually and quantitatively confirm the presence of vortices, jet wind and three-dimensional expansion of the planar blast wave near the exit. Pressure profiles at 90° orientation show flow separation. When cylinder is placed inside, this flow separation is not sustained, but when placed outside the shock tube this flow separation is sustained which causes tensile loading on the sides of the cylinder. Friedlander waves formed due to field explosives in the intermediate-to far-field ranges are replicated in a narrow test region located deep inside the shock tube.

  10. Mathematical modeling of velocity and number density profiles of particles across the flame propagation through a micro-iron dust cloud.

    PubMed

    Bidabadi, Mehdi; Haghiri, Ali; Rahbari, Alireza

    2010-04-15

    In this study, an attempt has been made to analytically investigate the concentration and velocity profiles of particles across flame propagation through a micro-iron dust cloud. In the first step, Lagrangian particle equation of motion during upward flame propagation in a vertical duct is employed and then forces acting upon the particle, such as thermophoretic force (resulted from the temperature gradient), gravitation and buoyancy are introduced; and consequently, the velocity profile as a function of the distance from the leading edge of the combustion zone is extracted. In the resumption, a control volume above the leading edge of the combustion zone is considered and the change in the particle number density in this control volume is obtained via the balance of particle mass fluxes passing through it. This study explains that the particle concentration at the leading edge of the combustion zone is more than the particle agglomeration in a distance far from the flame front. This increase in the particle aggregation above the combustion zone has a remarkable effect on the lower flammability limits of combustible particle cloud. It is worth noticing that the velocity and particle concentration profiles show a reasonable compatibility with the experimental data.

  11. Estimation of air concentrations and profiles for polychlorinated dibenzo-p-dioxins and dibenzofurans from calculated vegetation-air partition coefficients

    SciTech Connect

    Kjeller, L.O.; Rappe, C.; Jones, K.C.

    1995-12-31

    Air concentrations of vapor and particulate phase polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) are predicted by use of calculated plant-air partition coefficients. The plant-air interaction is reduced to an octanol-air distribution at equilibrium. Partition coefficients are deduced from the fugacity approach and calculated from congener group average data of solubility, vapor pressure and octanol-water partition coefficient. Calculated partition coefficients were used for prediction of the PCDD/F levels and congener profile in air from archived herbage collected pre- and post-1940. Before 1940 the air had a fly ash or combustion derived PCDD/F composition. After 1940 Hp and OCDD/F are superimposed on the combustion pattern, reflection of their release from the extensive use of polychlorinated compounds, notably penta chlorophenol, but also related compounds.

  12. Air-Sea Spray Airborne Radar Profiler Characterizes Energy Fluxes in Hurricanes

    NASA Technical Reports Server (NTRS)

    Durden, Stephen L.; Esteban-Fermandez, D.

    2010-01-01

    A report discusses ASAP (Air-sea Spray Airborne Profiler), a dual-wavelength radar profiler that provides measurement information about the droplet size distribution (DSD) of sea-spray, which can be used to estimate heat and moisture fluxes for hurricane research. Researchers have recently determined that sea spray can have a large effect on the magnitude and distribution of the air-sea energy flux at hurricane -force wind speeds. To obtain information about the DSD, two parameters of the DSD are required; for example, overall DSD amplitude and DSD mean diameter. This requires two measurements. Two frequencies are used, with a large enough separation that the differential frequency provides size information. One frequency is 94 GHz; the other is 220 GHz. These correspond to the Rayleigh and Mie regions. Above a surface wind speed of 10 m/ s, production of sea spray grows exponentially. Both the number of large droplets and the altitude they reach are a function of the surface wind speed.

  13. On Study of Air/Space-borne Dual-Wavelength Radar for Estimates of Rain Profiles

    NASA Technical Reports Server (NTRS)

    Liao, Liang; Meneghini, Robert

    2004-01-01

    In this study, a framework is discussed to apply air/space-borne dual-wavelength radar for the estimation of characteristic parameters of hydrometeors. The focus of our study is on the Global Precipitation Measurements (GPM) precipitation radar, a dual-wavelength radar that operates at Ku (13.8 GHz) and Ka (35 GHz) bands. As the droplet size distributions (DSD) of rain are expressed as the Gamma function, a procedure is described to derive the median volume diameter (D(sub 0)) and particle number concentration (N(sub T)) of rain. The correspondences of an important quantity of dual-wavelength radar, defined as deferential frequency ratio (DFR), to the D(sub 0) in the melting region are given as a function of the distance from the 0 C isotherm. A self-consistent iterative algorithm that shows a promising to account for rain attenuation of radar and infer the DSD without use of surface reference technique (SRT) is examined by applying it to the apparent radar reflectivity profiles simulated from the DSD model and then comparing the estimates with the model (true) results. For light to moderate rain the self-consistent rain profiling approach converges to unique and correct solutions only if the same shape factors of Gamma functions are used both to generate and retrieve the rain profiles, but does not converges to the true solutions if the DSD form is not chosen correctly. To further examine the dual-wavelength techniques, the self-consistent algorithm, along with forward and backward rain profiling algorithms, is then applied to the measurements taken from the 2nd generation Precipitation Radar (PR-2) built by Jet Propulsion Laboratory. It is found that rain profiles estimated from the forward and backward approaches are not sensitive to shape factor of DSD Gamma distribution, but the self-consistent method is.

  14. An estimate of solar wind velocity profiles in an coronal hole and a coronal streamer area (6-40 solar radius)

    NASA Technical Reports Server (NTRS)

    Paetzold, M.; Tsurutani, B. T.; Bird, M. K.

    1995-01-01

    Using the total electron content data obtained by the Ulysses Solar Corona Experiment during the superior solar conjunction in summer 1991, we selected two data sets, one associated with a coronal hole and the other one with coronal streamer crossings. By doing this data splitting, we find two entirely different density profiles varying as r(exp -2.7) and r(exp -2.3) for the coronal hole and coronal streamers, respectively. Assuming mass flux conservation from the inner corona to one AU, an estimate for the velocity profiles or acceleration in these two different regions can be determined. The more negative exponent of the coronal hole density profile indicates a more extended heating and acceleration region or more flaring, or both. Various possible explanations will be discussed.

  15. ARM - Midlatitude Continental Convective Clouds Experiment (MC3E): Multi-Frequency Profilers, Vertical Air Motion (williams-vertair)

    SciTech Connect

    Williams, Christopher; Jensen, Mike

    2012-11-06

    This data was collected by the NOAA 449-MHz and 2.8-GHz profilers in support of the Department of Energy (DOE) and NASA sponsored Mid-latitude Continental Convective Cloud Experiment (MC3E). The profiling radars were deployed in Northern Oklahoma at the DOE Atmospheric Radiation Mission (ARM) Southern Great Plans (SGP) Central Facility from 22 April through 6 June 2011. NOAA deployed three instruments: a Parsivel disdrometer, a 2.8-GHz profiler, and a 449-MHz profiler. The parasivel provided surface estimates of the raindrop size distribution and is the reference used to absolutely calibrate the 2.8 GHz profiler. The 2.8-GHz profiler provided unattenuated reflectivity profiles of the precipitation. The 449-MHz profiler provided estimates of the vertical air motion during precipitation from near the surface to just below the freezing level. By using the combination of 2.8-GHz and 449-MHz profiler observations, vertical profiles of raindrop size distributions can be retrieved. The profilers are often reference by their frequency band: the 2.8-GHz profiler operates in the S-band and the 449-MHz profiler operates in the UHF band. The raw observations are available as well as calibrated spectra and moments. This document describes how the instruments were deployed, how the data was collected, and the format of the archived data.

  16. Evaluation of the effect of media velocity on filter efficiency and most penetrating particle size of nuclear grade high-efficiency particulate air filters.

    PubMed

    Alderman, Steven L; Parsons, Michael S; Hogancamp, Kristina U; Waggoner, Charles A

    2008-11-01

    High-efficiency particulate air (HEPA) filters are widely used to control particulate matter emissions from processes that involve management or treatment of radioactive materials. Section FC of the American Society of Mechanical Engineers AG-1 Code on Nuclear Air and Gas Treatment currently restricts media velocity to a maximum of 2.5 cm/sec in any application where this standard is invoked. There is some desire to eliminate or increase this media velocity limit. A concern is that increasing media velocity will result in higher emissions of ultrafine particles; thus, it is unlikely that higher media velocities will be allowed without data to demonstrate the effect of media velocity on removal of ultrafine particles. In this study, the performance of nuclear grade HEPA filters, with respect to filter efficiency and most penetrating particle size, was evaluated as a function of media velocity. Deep-pleat nuclear grade HEPA filters (31 cm x 31 cm x 29 cm) were evaluated at media velocities ranging from 2.0 to 4.5 cm/sec using a potassium chloride aerosol challenge having a particle size distribution centered near the HEPA filter most penetrating particle size. Filters were challenged under two distinct mass loading rate regimes through the use of or exclusion of a 3 microm aerodynamic diameter cut point cyclone. Filter efficiency and most penetrating particle size measurements were made throughout the duration of filter testing. Filter efficiency measured at the onset of aerosol challenge was noted to decrease with increasing media velocity, with values ranging from 99.999 to 99.977%. The filter most penetrating particle size recorded at the onset of testing was noted to decrease slightly as media velocity was increased and was typically in the range of 110-130 nm. Although additional testing is needed, these findings indicate that filters operating at media velocities up to 4.5 cm/sec will meet or exceed current filter efficiency requirements. Additionally

  17. A Further Study of High Air Pollution Episodes in Taiwan Using the Microwave Temperature Profiler (MTP-5HE)

    NASA Astrophysics Data System (ADS)

    Chang, Che-Ming; Chang, Long-Nan; Hsiao, Hui-Chuan; Lu, Fang-Chuan; Shieh, Ping-Fei; Chen, Chi-Nan; Lu, Shish-Chong

    In the metropolitan areas of Taiwan with high population density, heavy traffic, and/or zones of heavy industries, serious air pollution episodes may occur during stable weather conditions. The information of mixing height is therefore essential to the air pollution control in this area. In this study, diurnal variation of the mixing height derived using the newly established EPA-Taiwan microwave temperature profiler (MTP-5HE) and that obtained through the CWB soundings are compared. The relationships between the air quality and the diurnal variation of the mixing height is discussed during different air pollution episodes.

  18. Temperature profile and producer gas composition of high temperature air gasification of oil palm fronds

    NASA Astrophysics Data System (ADS)

    Guangul, F. M.; Sulaiman, S. A.; Ramli, A.

    2013-06-01

    Environmental pollution and scarcity of reliable energy source are the current pressing global problems which need a sustainable solution. Conversion of biomass to a producer gas through gasification process is one option to alleviate the aforementioned problems. In the current research the temperature profile and composition of the producer gas obtained from the gasification of oil palm fronds by using high temperature air were investigated and compared with unheated air. By preheating the gasifying air at 500°C the process temperature were improved and as a result the concentration of combustible gases and performance of the process were improved. The volumetric percentage of CO, CH4 and H2 were improved from 22.49, 1.98, and 9.67% to 24.98, to 2.48% and 13.58%, respectively. In addition, HHV, carbon conversion efficiency and cold gas efficiency were improver from 4.88 MJ/Nm3, 83.8% and 56.1% to 5.90 MJ/Nm3, 87.3% and 62.4%, respectively.

  19. Piloted simulation of an air-ground profile negotiation process in a time-based Air Traffic Control environment

    NASA Technical Reports Server (NTRS)

    Williams, David H.; Green, Steven M.

    1993-01-01

    Historically, development of airborne flight management systems (FMS) and ground-based air traffic control (ATC) systems has tended to focus on different objectives with little consideration for operational integration. A joint program, between NASA's Ames Research Center (Ames) and Langley Research Center (Langley), is underway to investigate the issues of, and develop systems for, the integration of ATC and airborne automation systems. A simulation study was conducted to evaluate a profile negotiation process (PNP) between the Center/TRACON Automation System (CTAS) and an aircraft equipped with a four-dimensional flight management system (4D FMS). Prototype procedures were developed to support the functional implementation of this process. The PNP was designed to provide an arrival trajectory solution which satisfies the separation requirements of ATC while remaining as close as possible to the aircraft's preferred trajectory. Results from the experiment indicate the potential for successful incorporation of aircraft-preferred arrival trajectories in the CTAS automation environment. Fuel savings on the order of 2 percent to 8 percent, compared to fuel required for the baseline CTAS arrival speed strategy, were achieved in the test scenarios. The data link procedures and clearances developed for this experiment, while providing the necessary functionality, were found to be operationally unacceptable to the pilots. In particular, additional pilot control and understanding of the proposed aircraft-preferred trajectory, and a simplified clearance procedure were cited as necessary for operational implementation of the concept.

  20. Air

    MedlinePlus

    ... do to protect yourself from dirty air . Indoor air pollution and outdoor air pollution Air can be polluted indoors and it can ... this chart to see what things cause indoor air pollution and what things cause outdoor air pollution! Indoor ...

  1. Data Report. Volume I. Velocity and Temperature Profile Data for Zero Pressure Gradient, Fully Turbulent Boundary Layers.

    DTIC Science & Technology

    1981-01-01

    o I kru T V A L t’ CF Trvu-R1TL1;r rl;7LT 7 Z CALCLLtTCP DELTA = 6116T D!SrLACrm -T THICX!.%~c (LrLSTf!Z) = .l747f7426 ?A-,, rTU - Tl4-7 -XQ,-rS (TW-TA...2 g VELOCITY AND TEMPERATURE RATIOS ISA 0.0 U0 T~*T 30- VELOCITY AND TEMPERATURE DISTRIBUTIONS IN UNIVERSAL COORDINATES + 1O1 Figure 44. Boundary

  2. AirMOSS P-Band Radar Retrieval of Subcanopy Soil Moisture Profile

    NASA Astrophysics Data System (ADS)

    Tabatabaeenejad, A.; Burgin, M. S.; Duan, X.; Moghaddam, M.

    2013-12-01

    Knowledge of soil moisture, as a key variable of the Earth system, plays an important role in our under-standing of the global water, energy, and carbon cycles. The importance of such knowledge has led NASA to fund missions such as Soil Moisture Active and Passive (SMAP) and Airborne Microwave Observatory of Subcanopy and Subsurface (AirMOSS). The AirMOSS mission seeks to improve the estimates of the North American Net Ecosystem Exchange (NEE) by providing high-resolution observations of the root zone soil moisture (RZSM) over regions representative of the major North American biomes. AirMOSS flies a P-band SAR to penetrate vegetation and into the root zone to provide estimates of RZSM. The flights cover areas containing flux tower sites in regions from the boreal forests in Saskatchewan, Canada, to the tropical forests in La Selva, Costa Rica. The radar snapshots are used to generate estimates of RZSM via inversion of a scattering model of vegetation overlying soils with variable moisture profiles. These retrievals will be used to generate a time record of RZSM, which will be integrated with an ecosystem demography model in order to estimate the respiration and photosynthesis carbon fluxes. The aim of this work is the retrieval of the moisture profile over AirMOSS sites using the collected P-band radar data. We have integrated layered-soil scattering models into a forest scattering model; for the backscattering from ground and for the trunk-ground double-bounce mechanism, we have used a layered small perturbation method and a coherent scattering model of layered soil, respectively. To estimate the soil moisture profile, we represent it as a second-order polynomial in the form of az2 + bz + c, where z is the depth and a, b, and c are the coefficients to be retrieved from radar measurements. When retrieved, these coefficients give us the soil moisture up to a prescribed depth of validity. To estimate the unknown coefficients of the polynomial, we use simulated

  3. Water velocity at water-air interface is not zero: Comment on "Three-dimensional quantification of soil hydraulic properties using X-ray computed tomography and image-based modeling" by Saoirse R. Tracy et al.

    NASA Astrophysics Data System (ADS)

    Zhang, X. X.; Fan, X. Y.; Li, Z. Y.

    2016-07-01

    Tracy et al. (2015, doi: 10.1002/2014WR016020) assumed in their recent paper that water velocity at the water-air interface is zero in their pore-scale simulations of water flow in 3-D soil images acquired using X-ray computed tomography. We comment that such a treatment is physically wrong, and explain that it is the water-velocity gradient in the direction normal to the water-air interface, rather than the water velocity, that should be assumed to be zero at the water-air interface if one needs to decouple the water flow and the air flow. We analyze the potential errors caused by incorrectly taking water velocity at the water-air interface zero based on two simple examples, and conclude that it is not physically sound to make such a presumption because its associated errors are unpredictable.

  4. Effect of spaceflight on the maximal shortening velocity, morphology, and enzyme profile of fast- and slow-twitch skeletal muscle fibers in rhesus monkeys

    NASA Technical Reports Server (NTRS)

    Fitts, R. H.; Romatowski, J. G.; De La Cruz, L.; Widrick, J. J.; Desplanches, D.

    2000-01-01

    Weightlessness has been shown to cause limb muscle wasting and a reduced peak force and power in the antigravity soleus muscle. Despite a reduced peak power, Caiozzo et al. observed an increased maximal shortening velocity in the rat soleus muscle following a 14-day space flight. The major purpose of the present investigation was to determine if weightlessness induced an elevated velocity in the antigravity slow type I fibers of the rhesus monkey (Macaca mulatta), as well as to establish a cellular mechanism for the effect. Spaceflight or models of weightlessness have been shown to increase glucose uptake, elevate muscle glycogen content, and increase fatigability of the soleus muscle. The latter appears to be in part caused by a reduced ability of the slow oxidative fibers to oxidize fats. A second goal of this study was to establish the extent to which weightlessness altered the substrate profile and glycolytic and oxidative enzyme capacity of individual slow- and fast-twitch fibers.

  5. Water vapour mixing ratio profiles over Hornsund, Arctic. Intercomparison of lidar and AIRS results

    NASA Astrophysics Data System (ADS)

    Bloch, Magdalena; Karasiński, Grzegorz

    2014-04-01

    Since October 2009, a ground-based Raman lidar system has been deployed to perform a regular, night-time, vertical sounding of a water vapour content in the lower and middle troposphere above Polish Polar Station at Hornsund (77.00°N, 15.55°E, 10 m a.s.l.) in the Arctic. The water vapour mixing ratio profiles were obtained for the atmosphere up to 6 km altitude, based on analysis of inelastic Raman backscattering signals from nitrogen molecules (at 387 nm) and water vapour particles (at 407 nm), calibrated with the data from a local Vaisala's automatic meteorological station. The results obtained for winter seasons in the years 2009-2012 are in a good general agreement with the results obtained from the atmospheric infrared sounder (AIRS) on the Aqua satellite.

  6. In-air fluence profiles and water depth dose for uncollimated electron beams

    PubMed Central

    Toutaoui, Abedelkadar; Aichouche, Amar Nassim; Adjidir, Kenza Adjidir; Chami, Ahmed Chafik

    2008-01-01

    Advanced electron beam dose calculation models for radiation treatment planning systems require the input of a phase space beam model to configure a clinical electron beam in a computer. This beam model is a distribution in position, energy, and direction of electrons and photons in a plane in front of the patient. The phase space beam model can be determined by Monte Carlo simulation of the treatment head or from a limited set of measurements. In the latter case, parameters of the electron phase space beam model are obtained by fitting measured to calculated dosimetric data. In the present work, data for air fluence profiles and water depth doses have been presented for electron beams without an applicator for a medical linear accelerator. These data are used to parameterize the electron phase space beam model to a Monte Carlo dose calculation module available in the first commercial (MDS Nordion, now Nucletron) Monte Carlo treatment planning for electron beams. PMID:19893707

  7. Langley mobile ozone lidar: ozone and aerosol atmospheric profiling for air quality research.

    PubMed

    De Young, Russell; Carrion, William; Ganoe, Rene; Pliutau, Denis; Gronoff, Guillaume; Berkoff, Timothy; Kuang, Shi

    2017-01-20

    The Langley mobile ozone lidar (LMOL) is a mobile ground-based ozone lidar system that consists of a pulsed UV laser producing two UV wavelengths of 286 and 291 nm with energy of approximately 0.2  mJ/pulse and repetition rate of 1 kHz. The 527 nm pump laser is also transmitted for aerosol measurements. The receiver consists of a 40 cm parabolic telescope, which is used for both backscattered analog and photon counting. The lidar is very compact and highly mobile. This demonstrates the utility of very small lidar systems eventually leading to space-based ozone lidars. The lidar has been validated by numerous ozonesonde launches and has provided ozone curtain profiles from ground to approximately 4 km in support of air quality field missions.

  8. Constraints on the Profiles of Total Water PDF in AGCMs from AIRS and a High-Resolution Model

    NASA Technical Reports Server (NTRS)

    Molod, Andrea

    2012-01-01

    Atmospheric general circulation model (AGCM) cloud parameterizations generally include an assumption about the subgrid-scale probability distribution function (PDF) of total water and its vertical profile. In the present study, the Atmospheric Infrared Sounder (AIRS) monthly-mean cloud amount and relative humidity fields are used to compute a proxy for the second moment of an AGCM total water PDF called the RH01 diagnostic, which is the AIRS mean relative humidity for cloud fractions of 0.1 or less. The dependence of the second moment on horizontal grid resolution is analyzed using results from a high-resolution global model simulation.The AIRS-derived RH01 diagnostic is generally larger near the surface than aloft, indicating a narrower PDF near the surface, and varies with the type of underlying surface. High-resolution model results show that the vertical structure of profiles of the AGCM PDF second moment is unchanged as the grid resolution changes from 200 to 100 to 50 km, and that the second-moment profiles shift toward higher values with decreasing grid spacing.Several Goddard Earth Observing System, version 5 (GEOS-5), AGCM simulations were performed with several choices for the profile of the PDF second moment. The resulting cloud and relative humidity fields were shown to be quite sensitive to the prescribed profile, and the use of a profile based on the AIRS-derived proxy results in improvements relative to observational estimates. The AIRS-guided total water PDF profiles, including their dependence on underlying surface type and on horizontal resolution, have been implemented in the version of the GEOS-5 AGCM used for publicly released simulations.

  9. Airborne PCDD/F profiles in rural and urban areas of Buenos Aires Province, Argentina.

    PubMed

    Cappelletti, N; Astoviza, M; Migoya, M C; Colombo, J C

    2016-12-15

    Passive air samplers were deployed in 18 rural and urban locations in the densely populated Buenos Aires district to investigate airborne polychlorinated dibenzo-p-dioxin and polychlorinated-dibenzofuran (PCDD/Fs) profiles, sources and spatial patterns. Atmospheric concentrations reported as total toxic equivalents (TEQs), 2378-substituted (∑17PCDD/F) and 4-8 homologous groups (∑4-8PCDD/F) were highly variable and significantly correlated to urban scale. The rural average (3.0±2.7fgTEQm(-3)) was thirty times less than metropolitan values (90±51fgTEQm(-3)), with urban cluster (5.4±4.0fgTEQm(-3)) and urbanized area (33±50fgTEQm(-3)) in an intermediate position. A rural outlier exhibited the highest TEQ values (295-296fgTEQm(-3)) suggesting a local source. Principal component analyses (PCA) performed for ∑17PCDD/F and ∑4-8PCDD/F to identify source contributions showed more significant results for homologue groups compared to 17 congeners (83 and 45% of total variability explained, respectively) pointing to dominant diesel emissions enriched in TeCDF in rural areas, and open burning and industrial sources characterized by TeCDD, PeCDD contributing most in urbanized and metropolitan areas. Homologue group PCA also performed better clustering samples according to sources and TEQ concentrations. The PCDD/Fs profile of the rural outlier dominated by HxCDF and HpCDD/F showed a typical municipal incineration signature confirming the presence of local source.

  10. Influence of velocity effects on the shape of N2 (and air) broadened H2O lines revisited with classical molecular dynamics simulations

    NASA Astrophysics Data System (ADS)

    Ngo, N. H.; Tran, H.; Gamache, R. R.; Bermejo, D.; Domenech, J.-L.

    2012-08-01

    The modeling of the shape of H2O lines perturbed by N2 (and air) using the Keilson-Storer (KS) kernel for collision-induced velocity changes is revisited with classical molecular dynamics simulations (CMDS). The latter have been performed for a large number of molecules starting from intermolecular-potential surfaces. Contrary to the assumption made in a previous study [H. Tran, D. Bermejo, J.-L. Domenech, P. Joubert, R. R. Gamache, and J.-M. Hartmann, J. Quant. Spectrosc. Radiat. Transf. 108, 126 (2007)], 10.1016/j.jqsrt.2007.03.009, the results of these CMDS show that the velocity-orientation and -modulus changes statistically occur at the same time scale. This validates the use of a single memory parameter in the Keilson-Storer kernel to describe both the velocity-orientation and -modulus changes. The CMDS results also show that velocity- and rotational state-changing collisions are statistically partially correlated. A partially correlated speed-dependent Keilson-Storer model has thus been used to describe the line-shape. For this, the velocity changes KS kernel parameters have been directly determined from CMDS, while the speed-dependent broadening and shifting coefficients have been calculated with a semi-classical approach. Comparisons between calculated spectra and measurements of several lines of H2O broadened by N2 (and air) in the ν3 and 2ν1 + ν2 + ν3 bands for a wide range of pressure show very satisfactory agreement. The evolution of non-Voigt effects from Doppler to collisional regimes is also presented and discussed.

  11. Influence of velocity effects on the shape of N2 (and air) broadened H2O lines revisited with classical molecular dynamics simulations.

    PubMed

    Ngo, N H; Tran, H; Gamache, R R; Bermejo, D; Domenech, J-L

    2012-08-14

    The modeling of the shape of H(2)O lines perturbed by N(2) (and air) using the Keilson-Storer (KS) kernel for collision-induced velocity changes is revisited with classical molecular dynamics simulations (CMDS). The latter have been performed for a large number of molecules starting from intermolecular-potential surfaces. Contrary to the assumption made in a previous study [H. Tran, D. Bermejo, J.-L. Domenech, P. Joubert, R. R. Gamache, and J.-M. Hartmann, J. Quant. Spectrosc. Radiat. Transf. 108, 126 (2007)], the results of these CMDS show that the velocity-orientation and -modulus changes statistically occur at the same time scale. This validates the use of a single memory parameter in the Keilson-Storer kernel to describe both the velocity-orientation and -modulus changes. The CMDS results also show that velocity- and rotational state-changing collisions are statistically partially correlated. A partially correlated speed-dependent Keilson-Storer model has thus been used to describe the line-shape. For this, the velocity changes KS kernel parameters have been directly determined from CMDS, while the speed-dependent broadening and shifting coefficients have been calculated with a semi-classical approach. Comparisons between calculated spectra and measurements of several lines of H(2)O broadened by N(2) (and air) in the ν(3) and 2ν(1) + ν(2) + ν(3) bands for a wide range of pressure show very satisfactory agreement. The evolution of non-Voigt effects from Doppler to collisional regimes is also presented and discussed.

  12. Three-dimensional visualization of axial velocity profiles downstream of six different mechanical aortic valve prostheses, measured with a hot-film anemometer in a steady state flow model.

    PubMed

    Hasenkam, J M; Westphal, D; Reul, H; Gormsen, J; Giersiepen, M; Stodkilde-Jorgensen, H; Paulsen, P K

    1987-01-01

    Hot-film anemometry was used for in vitro steady-state measurements downstream of six mechanical aortic valve prostheses at flow rates 10, 20 and 30 l.min-1. Three-dimensional visualizations of velocity profiles at two downstream levels were made with the valves rotated 0 and 60 degrees in relation to the sinuses of valsalvae. The velocity fields downstream of the disc valves were generally skew with increasing velocity gradients and laminar shear stresses with increasing flow rates. Furthermore, increased skewness of the velocity profiles was noticed when the major orifices of the disc valves were towards the commissure than when approaching a sinus of valsalvae. The velocity profiles downstream of the ball valve were generally flat but with considerably more disturbed flow, consistent with the findings in turbulent flow.

  13. Mixture model-based atmospheric air mass classification: a probabilistic view of thermodynamic profiles

    NASA Astrophysics Data System (ADS)

    Pernin, Jérôme; Vrac, Mathieu; Crevoisier, Cyril; Chédin, Alain

    2016-10-01

    Air mass classification has become an important area in synoptic climatology, simplifying the complexity of the atmosphere by dividing the atmosphere into discrete similar thermodynamic patterns. However, the constant growth of atmospheric databases in both size and complexity implies the need to develop new adaptive classifications. Here, we propose a robust unsupervised and supervised classification methodology of a large thermodynamic dataset, on a global scale and over several years, into discrete air mass groups homogeneous in both temperature and humidity that also provides underlying probability laws. Temperature and humidity at different pressure levels are aggregated into a set of cumulative distribution function (CDF) values instead of classical ones. The method is based on a Gaussian mixture model and uses the expectation-maximization (EM) algorithm to estimate the parameters of the mixture. Spatially gridded thermodynamic profiles come from ECMWF reanalyses spanning the period 2000-2009. Different aspects are investigated, such as the sensitivity of the classification process to both temporal and spatial samplings of the training dataset. Comparisons of the classifications made either by the EM algorithm or by the widely used k-means algorithm show that the former can be viewed as a generalization of the latter. Moreover, the EM algorithm delivers, for each observation, the probabilities of belonging to each class, as well as the associated uncertainty. Finally, a decision tree is proposed as a tool for interpreting the different classes, highlighting the relative importance of temperature and humidity in the classification process.

  14. A bayesian approach for determining velocity and uncertainty estimates from seismic cone penetrometer testing or vertical seismic profiling data

    USGS Publications Warehouse

    Pidlisecky, A.; Haines, S.S.

    2011-01-01

    Conventional processing methods for seismic cone penetrometer data present several shortcomings, most notably the absence of a robust velocity model uncertainty estimate. We propose a new seismic cone penetrometer testing (SCPT) data-processing approach that employs Bayesian methods to map measured data errors into quantitative estimates of model uncertainty. We first calculate travel-time differences for all permutations of seismic trace pairs. That is, we cross-correlate each trace at each measurement location with every trace at every other measurement location to determine travel-time differences that are not biased by the choice of any particular reference trace and to thoroughly characterize data error. We calculate a forward operator that accounts for the different ray paths for each measurement location, including refraction at layer boundaries. We then use a Bayesian inversion scheme to obtain the most likely slowness (the reciprocal of velocity) and a distribution of probable slowness values for each model layer. The result is a velocity model that is based on correct ray paths, with uncertainty bounds that are based on the data error. ?? NRC Research Press 2011.

  15. Optimal Area Profiles for Ideal Single Nozzle Air-Breathing Pulse Detonation Engines

    NASA Technical Reports Server (NTRS)

    Paxson, Daniel E.

    2003-01-01

    The effects of cross-sectional area variation on idealized Pulse Detonation Engine performance are examined numerically. A quasi-one-dimensional, reacting, numerical code is used as the kernel of an algorithm that iteratively determines the correct sequencing of inlet air, inlet fuel, detonation initiation, and cycle time to achieve a limit cycle with specified fuel fraction, and volumetric purge fraction. The algorithm is exercised on a tube with a cross sectional area profile containing two degrees of freedom: overall exit-to-inlet area ratio, and the distance along the tube at which continuous transition from inlet to exit area begins. These two parameters are varied over three flight conditions (defined by inlet total temperature, inlet total pressure and ambient static pressure) and the performance is compared to a straight tube. It is shown that compared to straight tubes, increases of 20 to 35 percent in specific impulse and specific thrust are obtained with tubes of relatively modest area change. The iterative algorithm is described, and its limitations are noted and discussed. Optimized results are presented showing performance measurements, wave diagrams, and area profiles. Suggestions for future investigation are also discussed.

  16. Development of a Spatially Resolving X-Ray Crystal Spectrometer (XCS) for Measurement of Ion-Temperature (Ti) and Rotation-Velocity (v) Profiles in ITER

    SciTech Connect

    Hill, K W; Delgado-Aprico, L; Johnson, D; Feder, R; Beiersdorfer,; Dunn, J; Morris, K; Wang, E; Reinke, M; Podpaly, Y; Rice, J E; Barnsley, R; O'Mullane, M; Lee, S G

    2010-05-21

    Imaging XCS arrays are being developed as a US-ITER activity for Doppler measurement of Ti and v profiles of impurities (W, Kr, Fe) with ~7 cm (a/30) and 10-100 ms resolution in ITER. The imaging XCS, modeled after a PPPL-MIT instrument on Alcator C-Mod, uses a spherically bent crystal and 2d x-ray detectors to achieve high spectral resolving power (E/dE>6000) horizontally and spatial imaging vertically. Two arrays will measure Ti and both poloidal and toroidal rotation velocity profiles. Measurement of many spatial chords permits tomographic inversion for inference of local parameters. The instrument design, predictions of performance, and results from C-Mod will be presented.

  17. Development of a spatially resolving x-ray crystal spectrometer for measurement of ion-temperature (T[sub i]) and rotation-velocity (v) profiles in ITER

    SciTech Connect

    Hill, K. W.; Bitter, M.; Delgado-Aparicio, L.; Johnson, D.; Feder, R.; Beiersdorfer, P.; Dunn, J.; Morris, K.; Wang, E.; Reinke, M.; Podpaly, Y.; Rice, J. E.; Barnsley, R.; O’Mullane, M.; Lee, S. G.

    2010-01-01

    Imaging x-ray crystal spectrometer XCS arrays are being developed as a US-ITER activity for Doppler measurement of Ti and v profiles of impurities (W, Kr, and Fe) with ~ 7 cm (a/30) and 10-100 ms resolution in ITER. The imaging XCS, modeled after a prototype instrument on Alcator C-Mod, uses a spherically bent crystal and 2D x-ray detectors to achieve high spectral resolving power (E / dE > 6000) horizontally and spatial imaging vertically. Two arrays will measure Ti and both poloidal and toroidal rotation velocity profiles. The measurement of many spatial chords permits tomographic inversion for the inference of local parameters. The instrument design, predictions of performance, and results from C-Mod are presented.

  18. Development of a spatially resolving x-ray crystal spectrometer for measurement of ion-temperature (T{sub i}) and rotation-velocity (v) profiles in ITER

    SciTech Connect

    Hill, K. W.; Bitter, M.; Delgado-Aparicio, L.; Johnson, D.; Feder, R.; Beiersdorfer, P.; Dunn, J.; Morris, K.; Wang, E.; Reinke, M.; Podpaly, Y.; Rice, J. E.; Barnsley, R.; O'Mullane, M.; Lee, S. G.

    2010-10-15

    Imaging x-ray crystal spectrometer (XCS) arrays are being developed as a US-ITER activity for Doppler measurement of T{sub i} and v profiles of impurities (W, Kr, and Fe) with {approx}7 cm (a/30) and 10-100 ms resolution in ITER. The imaging XCS, modeled after a prototype instrument on Alcator C-Mod, uses a spherically bent crystal and 2D x-ray detectors to achieve high spectral resolving power (E/dE>6000) horizontally and spatial imaging vertically. Two arrays will measure T{sub i} and both poloidal and toroidal rotation velocity profiles. The measurement of many spatial chords permits tomographic inversion for the inference of local parameters. The instrument design, predictions of performance, and results from C-Mod are presented.

  19. PROFILE: Potential for Advanced Technology to Improve Air Quality and Human Health in Shanghai.

    PubMed

    STREETS; HEDAYAT; CARMICHAEL; ARNDT; CARTER

    1999-04-01

    / Air quality in most Asian cities is poor and getting worse. It will soon become impossible to sustain population, economic, and industrial growth without severe deterioration of the atmospheric environment. This paper addresses the city of Shanghai, the air-quality problems it faces over the next 30 years, and the potential of advanced technology to alleviate these problems. Population, energy consumption, and emission profiles are developed for the city at 0.1 degrees x 0.1 degrees resolution and extrapolated from 1990 to 2020 using sector-specific economic growth factors. Within the context of the RAINS-Asia model, eight technology scenarios are examined for their effects on ambient concentrations of sulfur dioxide and sulfate and their emission control costs. Without new control measures, it is projected that the number of people exposed to sulfur dioxide concentrations in excess of guidelines established by the World Health Organization will rise from 650,000 in 1990 to more than 14 million in 2020. It is apparent that efforts to reduce emissions are likely to have significant health benefits, measured in terms of the cost of reducing the number of people exposed to concentrations in excess of the guidelines ($10-50 annually per person protected). Focusing efforts on the control of new coal-fired power plants and industrial facilities has the greatest benefit. However, none of the scenarios examined is alone capable of arresting the increases in emissions, concentrations, and population exposure. It is concluded that combinations of stringent scenarios in several sectors will be necessary to stabilize the situation, at a potential cost of $500 million annually by the year 2020. KEY WORDS: Coal; China; Shanghai; Sulfur dioxide; Air quality; Health effects

  20. A New Ionosphere Tomography Algorithm with Two-Grids Virtual Observations Constraints and 3D Velocity Profile

    NASA Astrophysics Data System (ADS)

    Kong, Jian; Yao, Yibin; Shum, Che-Kwan

    2014-05-01

    Due to the sparsity of world's GNSS stations and limitations of projection angles, GNSS-based ionosphere tomography is a typical ill-posed problem. There are two main ways to solve this problem. Firstly the joint inversion method combining multi-source data is one of the effective ways. Secondly using a priori or reference ionosphere models, e.g., IRI or GIM models, as the constraints to improve the state of normal equation is another effective approach. The traditional way for adding constraints with virtual observations can only solve the problem of sparse stations but the virtual observations still lack horizontal grid constraints therefore unable to fundamentally improve the near-singularity characteristic of the normal equation. In this paper, we impose a priori constraints by increasing the virtual observations in n-dimensional space, which can greatly reduce the condition number of the normal equation. Then after the inversion region is gridded, we can form a stable structure among the grids with loose constraints. We then further consider that the ionosphere indeed changes within certain temporal scale, e.g., two hours. In order to establish a more sophisticated and realistic ionosphere model and obtain the real time ionosphere electron density velocity (IEDV) information, we introduce the grid electron density velocity parameters, which can be estimated with electron density parameters simultaneously. The velocity parameters not only can enhance the temporal resolution of the ionosphere model thereby reflecting more elaborate structure (short-term disturbances) under ionosphere disturbances status, but also provide a new way for the real-time detection and prediction of ionosphere 3D changes. We applied the new algorithm to the GNSS data collected in Europe for tomography inversion for ionosphere electron density and velocity at 2-hour resolutions, which are consistent throughout the whole day variation. We then validate the resulting tomography model

  1. SGP and TWP (Manus) Ice Cloud Vertical Velocities

    DOE Data Explorer

    Kalesse, Heike

    2013-06-27

    Daily netcdf-files of ice-cloud dynamics observed at the ARM sites at SGP (Jan1997-Dec2010) and Manus (Jul1999-Dec2010). The files include variables at different time resolution (10s, 20min, 1hr). Profiles of radar reflectivity factor (dbz), Doppler velocity (vel) as well as retrieved vertical air motion (V_air) and reflectivity-weighted particle terminal fall velocity (V_ter) are given at 10s, 20min and 1hr resolution. Retrieved V_air and V_ter follow radar notation, so positive values indicate downward motion. Lower level clouds are removed, however a multi-layer flag is included.

  2. First seismic shear wave velocity profile of the lunar crust as extracted from the Apollo 17 active seismic data by wavefield gradient analysis

    NASA Astrophysics Data System (ADS)

    Sollberger, David; Schmelzbach, Cedric; Robertsson, Johan O. A.; Greenhalgh, Stewart A.; Nakamura, Yosio; Khan, Amir

    2016-04-01

    We present a new seismic velocity model of the shallow lunar crust, including, for the first time, shear wave velocity information. So far, the shear wave velocity structure of the lunar near-surface was effectively unconstrained due to the complexity of lunar seismograms. Intense scattering and low attenuation in the lunar crust lead to characteristic long-duration reverberations on the seismograms. The reverberations obscure later arriving shear waves and mode conversions, rendering them impossible to identify and analyze. Additionally, only vertical component data were recorded during the Apollo active seismic experiments, which further compromises the identification of shear waves. We applied a novel processing and analysis technique to the data of the Apollo 17 lunar seismic profiling experiment (LSPE), which involved recording seismic energy generated by several explosive packages on a small areal array of four vertical component geophones. Our approach is based on the analysis of the spatial gradients of the seismic wavefield and yields key parameters such as apparent phase velocity and rotational ground motion as a function of time (depth), which cannot be obtained through conventional seismic data analysis. These new observables significantly enhance the data for interpretation of the recorded seismic wavefield and allow, for example, for the identification of S wave arrivals based on their lower apparent phase velocities and distinct higher amount of generated rotational motion relative to compressional (P-) waves. Using our methodology, we successfully identified pure-mode and mode-converted refracted shear wave arrivals in the complex LSPE data and derived a P- and S-wave velocity model of the shallow lunar crust at the Apollo 17 landing site. The extracted elastic-parameter model supports the current understanding of the lunar near-surface structure, suggesting a thin layer of low-velocity lunar regolith overlying a heavily fractured crust of basaltic

  3. Ballistic Range Measurements of Stagnation-Point Heat Transfer in Air and in Carbon Dioxide at Velocities up to 18,000 Feet Per Second

    NASA Technical Reports Server (NTRS)

    Yee, Layton; Bailey, Harry E.; Woodward, Henry T.

    1961-01-01

    A new technique for measuring heat-transfer rates on free-flight models in a ballistic range is described in this report. The accuracy of the heat-transfer rates measured in this way is shown to be comparable with the accuracy obtained in shock-tube measurements. The specific results of the present experiments consist of measurements of the stagnation-point heat-transfer rates experienced by a spherical-nosed model during flight through air and through carbon dioxide at velocities up to 18,000 feet per second. For flight through air these measured heat-transfer rates agree well with both the theoretically predicted rates and the rates measured in shock tubes. the heat-transfer rates agree well with the rates measured in a shock tube. Two methods of estimating the stagnation-point heat-transfer rates in carbon dioxide are compared with the experimental measurements. At each velocity the measured stagnation-point heat-transfer rate in carbon dioxide is about the same as the measured heat-transfer rate in air.

  4. Evaluation of Gust and Draft Velocities from Flights of P-61C Airplanes within Thunderstorms September 10, 1947 to September 15, 1947 at Clinton County Army Air Field, Ohio

    NASA Technical Reports Server (NTRS)

    Funk, Jack

    1948-01-01

    The gust and draft velocities from records of NACA instruments installed in P-61C airplanes participating in thunderstorm flights at Clinton County Army Air Field, Ohio, from September 10, 1947 to September 15, 1947, are presented.

  5. Evaluation of Gust and Draft Velocities from Flights of P-61C Airplanes within Thunderstorms August 16, 1947 to August 20, 1947 at Clinton County Army Air Field, Ohio

    NASA Technical Reports Server (NTRS)

    Funk, Jack

    1948-01-01

    The gust and draft velocities from records of NACA instruments installed in P-61C airplanes participating in thunderstorm flights at Clinton County Army Air Field, Ohio, from August 16, 1947 to August 20, 1947 are presented.

  6. Evaluation of Gust and Draft Velocities from Flights of P-61C Airplanes within Thunderstorms August 13, 1947 to August 15, 1947 at Clinton County Army Air Field, Ohio

    NASA Technical Reports Server (NTRS)

    Funk, Jack

    1948-01-01

    The gust and draft velocities from records of NACA instruments installed in P-61C airplanes participating in thunderstorm flights at Clinton County Army Air Field, Ohio, from August 13, 1947 to August 15, 1947 are presented.

  7. Demonstrating the Operational Value of Atmospheric Infrared Sounder (AIRS) Retrieved Profiles in the Pre-Convective Environment

    NASA Technical Reports Server (NTRS)

    Kozlowski, Danielle M.; Zavodsky, T.; Jedloved, Gary J.

    2011-01-01

    The Short-term Prediction Research and Transition Center (SPoRT) is a collaborative partnership between NASA and operational forecasting partners, including a number of National Weather Service offices. SPoRT provides real-time NASA products and capabilities to its partners to address specific operational forecast challenges. One operational forecast challenge is forecasting convective weather in data-void regions such as large bodies of water (e.g. Gulf of Mexico). To address this forecast challenge, SPoRT produces a twice-daily three-dimensional analysis that blends a model first-guess from the Advanced Research Weather Research and Forecasting (WRF-ARW) model with retrieved profiles from the Atmospheric Infrared Sounder (AIRS) -- a hyperspectral sounding instrument aboard NASA's Aqua satellite that provides temperature and moisture profiles of the atmosphere. AIRS profiles are unique in that they give a three dimensional view of the atmosphere that is not available through the current rawinsonde network. AIRS has two overpass swaths across North America each day, one valid in the 0700-0900 UTC timeframe and the other in the 1900-2100 UTC timeframe. This is helpful because the rawinsonde network only has data from 0000 UTC and 1200 UTC at specific land-based locations. Comparing the AIRS analysis product with control analyses that include no AIRS data demonstrates the value of the retrieved profiles to situational awareness for the pre-convective (and convective) environment. In an attempt to verify that the AIRS analysis was a good representation of the vertical structure of the atmosphere, both the AIRS and control analyses are compared to a Rapid Update Cycle (RUC) analysis used by operational forecasters. Using guidance from operational forecasters, convective available potential energy (CAPE) was determined to be a vital variable in making convective forecasts and is used herein to demonstrate the utility of the AIRS profiles in changing the vertical

  8. Analysis of Vertical Profiles of Reflectivity and Doppler Velocity from ER2-HIWRAP in Convective Clouds During MC3E

    NASA Astrophysics Data System (ADS)

    Tian, L.; Heymsfield, G. M.; Liao, L.; Meneghini, R.; Grecu, M.

    2013-12-01

    Retrieval of precipitation in mixed-phase region in convection over land is a challenging problem in GPM DPR algorithm. Dual-wavelength (Ku/Ka band) airborne radar observations from the NASA's ER2-HIWRAP radar system in deep convections during MC3E provide observations that can be used to test assumptions in the algorithm for retrievals in the mixed-phase region. In this study, we use the reflectivity and Doppler velocity from ER2-HIWRAP, and Zh and ZDR from ground-based polarimetric radar to show that the present of mixed-phased hydrometeor (e.g., water-coated hail/graupel) produces a scattering signature similar to the bright band in stratiform rain. Such signature may be used to identify the mixed phased region in deep convective storm. We will also discuss implications of using this information for the GPM radar and radiometer retrieval algorithms.

  9. Measuring air-sea gas-exchange velocities in a large-scale annular wind-wave tank

    NASA Astrophysics Data System (ADS)

    Mesarchaki, E.; Kräuter, C.; Krall, K. E.; Bopp, M.; Helleis, F.; Williams, J.; Jähne, B.

    2015-01-01

    In this study we present gas-exchange measurements conducted in a large-scale wind-wave tank. Fourteen chemical species spanning a wide range of solubility (dimensionless solubility, α = 0.4 to 5470) and diffusivity (Schmidt number in water, Scw = 594 to 1194) were examined under various turbulent (u10 = 0.73 to 13.2 m s-1) conditions. Additional experiments were performed under different surfactant modulated (two different concentration levels of Triton X-100) surface states. This paper details the complete methodology, experimental procedure and instrumentation used to derive the total transfer velocity for all examined tracers. The results presented here demonstrate the efficacy of the proposed method, and the derived gas-exchange velocities are shown to be comparable to previous investigations. The gas transfer behaviour is exemplified by contrasting two species at the two solubility extremes, namely nitrous oxide (N2O) and methanol (CH3OH). Interestingly, a strong transfer velocity reduction (up to a factor of 3) was observed for the relatively insoluble N2O under a surfactant covered water surface. In contrast, the surfactant effect for CH3OH, the high solubility tracer, was significantly weaker.

  10. Effects of air velocity on laying hen production from 24 to 27 weeks under simulated evaporatively cooled conditions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Thermal conditions play a major role in production efficiency in commercial poultry production. Mitigation of thermal stress can improve productivity, but must be achieved economically. Weather and system design can limit effectiveness of evaporative cooling and increased air movement has been sho...

  11. Error estimations of dry deposition velocities of air pollutants using bulk sea surface temperature under common assumptions

    NASA Astrophysics Data System (ADS)

    Lan, Yung-Yao; Tsuang, Ben-Jei; Keenlyside, Noel; Wang, Shu-Lun; Arthur Chen, Chen-Tung; Wang, Bin-Jye; Liu, Tsun-Hsien

    2010-07-01

    It is well known that skin sea surface temperature (SSST) is different from bulk sea surface temperature (BSST) by a few tenths of a degree Celsius. However, the extent of the error associated with dry deposition (or uptake) estimation by using BSST is not well known. This study tries to conduct such an evaluation using the on-board observation data over the South China Sea in the summers of 2004 and 2006. It was found that when a warm layer occurred, the deposition velocities using BSST were underestimated within the range of 0.8-4.3%, and the absorbed sea surface heat flux was overestimated by 21 W m -2. In contrast, under cool skin only conditions, the deposition velocities using BSST were overestimated within the range of 0.5-2.0%, varying with pollutants and the absorbed sea surface heat flux was underestimated also by 21 W m -2. Scale analysis shows that for a slightly soluble gas (e.g., NO 2, NO and CO), the error in the solubility estimation using BSST is the major source of the error in dry deposition estimation. For a highly soluble gas (e.g., SO 2), the error in the estimation of turbulent heat fluxes and, consequently, aerodynamic resistance and gas-phase film resistance using BSST is the major source of the total error. In contrast, for a medium soluble gas (e.g., O 3 and CO 2) both the errors from the estimations of the solubility and aerodynamic resistance are important. In addition, deposition estimations using various assumptions are discussed. The largest uncertainty is from the parameterizations for chemical enhancement factors. Other important areas of uncertainty include: (1) various parameterizations for gas-transfer velocity; (2) neutral-atmosphere assumption; (3) using BSST as SST, and (4) constant pH value assumption.

  12. Studies of the acoustic transmission characteristics of coaxial nozzles with inverted velocity profiles, volume 1. [jet engine noise radiation through coannular exhaust nozzles

    NASA Technical Reports Server (NTRS)

    Dean, P. D.; Salikuddin, M.; Ahuja, K. K.; Plumblee, H. E.; Mungur, P.

    1979-01-01

    The efficiency of internal noise radiation through coannular exhaust nozzle with an inverted velocity profile was studied. A preliminary investigation was first undertaken to: (1) define the test parameters which influence the internal noise radiation; (2) develop a test methodology which could realistically be used to examine the effects of the test parameters; (3) and to validate this methodology. The result was the choice of an acoustic impulse as the internal noise source in the in the jet nozzles. Noise transmission characteristics of a nozzle system were then investigated. In particular, the effects of fan nozzle convergence angle, core extention length to annulus height ratio, and flow Mach number and temperatures were studied. The results are presented as normalized directivity plots.

  13. Strain-induced extinction of hydrogen-air counterflow diffusion flames - Effects of steam, CO2, N2, and O2 additives to air

    NASA Technical Reports Server (NTRS)

    Pellett, G. L.; Northam, G. B.; Wilson, L. G.

    1992-01-01

    A fundamental study was performed using axisymmetric nozzle and tubular opposed jet burners to measure the effects of laminar plug flow and parabolic input velocity profiles on the extinction limits of H2-air counterflow diffusion flames. Extinction limits were quantified by 'flame strength', (average axial air jet velocity) at blowoff of the central flame. The effects of key air contaminants, on the extinction limits, are characterized and analyzed relative to utilization of combustion contaminated vitiated air in high enthalpy supersonic test facilities.

  14. Application of acoustic-Doppler current profiler and expendable bathythermograph measurements to the study of the velocity structure and transport of the Gulf Stream

    NASA Technical Reports Server (NTRS)

    Joyce, T. M.; Dunworth, J. A.; Schubert, D. M.; Stalcup, M. C.; Barbour, R. L.

    1988-01-01

    The degree to which Acoustic-Doppler Current Profiler (ADCP) and expendable bathythermograph (XBT) data can provide quantitative measurements of the velocity structure and transport of the Gulf Stream is addressed. An algorithm is used to generate salinity from temperature and depth using an historical Temperature/Salinity relation for the NW Atlantic. Results have been simulated using CTD data and comparing real and pseudo salinity files. Errors are typically less than 2 dynamic cm for the upper 800 m out of a total signal of 80 cm (across the Gulf Stream). When combined with ADCP data for a near-surface reference velocity, transport errors in isopycnal layers are less than about 1 Sv (10 to the 6th power cu m/s), as is the difference in total transport for the upper 800 m between real and pseudo data. The method is capable of measuring the real variability of the Gulf Stream, and when combined with altimeter data, can provide estimates of the geoid slope with oceanic errors of a few parts in 10 to the 8th power over horizontal scales of 500 km.

  15. The potential of LIRIC to validate the vertical profiles of the aerosol mass concentration estimated by an air quality model

    NASA Astrophysics Data System (ADS)

    Siomos, Nikolaos; Filoglou, Maria; Poupkou, Anastasia; Liora, Natalia; Dimopoulos, Spyros; Melas, Dimitris; Chaikovsky, Anatoli; Balis, Dimitris

    2015-04-01

    Vertical profiles of the aerosol mass concentration derived by a retrieval algorithm that uses combined sunphotometer and LIDAR data (LIRIC) were used in order to validate the mass concentration profiles estimated by the air quality model CAMx. LIDAR and CIMEL measurements of the Laboratory of Atmospheric Physics of the Aristotle University of Thessaloniki were used for this validation.The aerosol mass concentration profiles of the fine and coarse mode derived by CAMx were compared with the respective profiles derived by the retrieval algorithm. For the coarse mode particles, forecasts of the Saharan dust transportation model BSC-DREAM8bV2 were also taken into account. Each of the retrieval algorithm's profiles were matched to the models' profile with the best agreement within a time window of four hours before and after the central measurement. OPAC, a software than can provide optical properties of aerosol mixtures, was also employed in order to calculate the angstrom exponent and the lidar ratio values for 355nm and 532nm for each of the model's profiles aiming in a comparison with the angstrom exponent and the lidar ratio values derived by the retrieval algorithm for each measurement. The comparisons between the fine mode aerosol concentration profiles resulted in a good agreement between CAMx and the retrieval algorithm, with the vertical mean bias error never exceeding 7 μgr/m3. Concerning the aerosol coarse mode concentration profiles both CAMx and BSC-DREAM8bV2 values are severely underestimated, although, in cases of Saharan dust transportation events there is an agreement between the profiles of BSC-DREAM8bV2 model and the retrieval algorithm.

  16. A Computational and Experimental Study of Coflow Laminar Methane/Air Diffusion Flames: Effects of Fuel Dilution, Inlet Velocity, and Gravity

    NASA Technical Reports Server (NTRS)

    Cao, S.; Ma, B.; Bennett, B. A. V.; Giassi, D.; Stocker, D. P.; Takahashi, F.; Long, M. B.; Smooke, M. D.

    2014-01-01

    The influences of fuel dilution, inlet velocity, and gravity on the shape and structure of laminar coflow CH4-air diffusion flames were investigated computationally and experimentally. A series of nitrogen-diluted flames measured in the Structure and Liftoff in Combustion Experiment (SLICE) on board the International Space Station was assessed numerically under microgravity (mu g) and normal gravity (1g) conditions with CH4 mole fraction ranging from 0.4 to 1.0 and average inlet velocity ranging from 23 to 90 cm/s. Computationally, the MC-Smooth vorticity-velocity formulation was employed to describe the reactive gaseous mixture, and soot evolution was modeled by sectional aerosol equations. The governing equations and boundary conditions were discretized on a two-dimensional computational domain by finite differences, and the resulting set of fully coupled, strongly nonlinear equations was solved simultaneously at all points using a damped, modified Newton's method. Experimentally, flame shape and soot temperature were determined by flame emission images recorded by a digital color camera. Very good agreement between computation and measurement was obtained, and the conclusions were as follows. (1) Buoyant and nonbuoyant luminous flame lengths are proportional to the mass flow rate of the fuel mixture; computed and measured nonbuoyant flames are noticeably longer than their 1g counterparts; the effect of fuel dilution on flame shape (i.e., flame length and flame radius) is negligible when the flame shape is normalized by the methane flow rate. (2) Buoyancy-induced reduction of the flame radius through radially inward convection near the flame front is demonstrated. (3) Buoyant and nonbuoyant flame structure is mainly controlled by the fuel mass flow rate, and the effects from fuel dilution and inlet velocity are secondary.

  17. CLASH-VLT: The mass, velocity-anisotropy, and pseudo-phase-space density profiles of the z = 0.44 galaxy cluster MACS J1206.2-0847

    NASA Astrophysics Data System (ADS)

    Biviano, A.; Rosati, P.; Balestra, I.; Mercurio, A.; Girardi, M.; Nonino, M.; Grillo, C.; Scodeggio, M.; Lemze, D.; Kelson, D.; Umetsu, K.; Postman, M.; Zitrin, A.; Czoske, O.; Ettori, S.; Fritz, A.; Lombardi, M.; Maier, C.; Medezinski, E.; Mei, S.; Presotto, V.; Strazzullo, V.; Tozzi, P.; Ziegler, B.; Annunziatella, M.; Bartelmann, M.; Benitez, N.; Bradley, L.; Brescia, M.; Broadhurst, T.; Coe, D.; Demarco, R.; Donahue, M.; Ford, H.; Gobat, R.; Graves, G.; Koekemoer, A.; Kuchner, U.; Melchior, P.; Meneghetti, M.; Merten, J.; Moustakas, L.; Munari, E.; Regős, E.; Sartoris, B.; Seitz, S.; Zheng, W.

    2013-10-01

    Aims: We constrain the mass, velocity-anisotropy, and pseudo-phase-space density profiles of the z = 0.44 CLASH cluster MACS J1206.2-0847, using the projected phase-space distribution of cluster galaxies in combination with gravitational lensing. Methods: We use an unprecedented data-set of ≃600 redshifts for cluster members, obtained as part of a VLT/VIMOS large program, to constrain the cluster mass profile over the radial range ~0-5 Mpc (0-2.5 virial radii) using the MAMPOSSt and Caustic methods. We then add external constraints from our previous gravitational lensing analysis. We invert the Jeans equation to obtain the velocity-anisotropy profiles of cluster members. With the mass-density and velocity-anisotropy profiles we then obtain the first determination of a cluster pseudo-phase-space density profile. Results: The kinematics and lensing determinations of the cluster mass profile are in excellent agreement. This is very well fitted by a NFW model with mass M200 = (1.4 ± 0.2) × 1015 M⊙ and concentration c200 = 6 ± 1, only slightly higher than theoretical expectations. Other mass profile models also provide acceptable fits to our data, of (slightly) lower (Burkert, Hernquist, and Softened Isothermal Sphere) or comparable (Einasto) quality than NFW. The velocity anisotropy profiles of the passive and star-forming cluster members are similar, close to isotropic near the center and increasingly radial outside. Passive cluster members follow extremely well the theoretical expectations for the pseudo-phase-space density profile and the relation between the slope of the mass-density profile and the velocity anisotropy. Star-forming cluster members show marginal deviations from theoretical expectations. Conclusions: This is the most accurate determination of a cluster mass profile out to a radius of 5 Mpc, and the only determination of the velocity-anisotropy and pseudo-phase-space density profiles of both passive and star-forming galaxies for an individual

  18. The impact of drought and air pollution on metal profiles in peat cores.

    PubMed

    Souter, Laura; Watmough, Shaun A

    2016-01-15

    Peat cores have long been used to reconstruct atmospheric metal deposition; however, debate remains regarding how well historical depositional patterns are preserved in peat. This study examined peat cores sampled from 14 peatlands in the Sudbury region of Ontario, Canada, which has a well-documented history of acid and metal deposition. Copper (Cu) and lead (Pb) concentrations within individual peat cores were strongly correlated and were elevated in the upper 10 cm, especially in the sites closest to the main Copper Cliff smelter. In contrast, nickel (Ni) and cobalt (Co) concentrations were often elevated at depths greater than 10 cm, indicating much greater post-depositional movement of these metals compared with Cu and Pb. Post-depositional movement of metals is supported by the observation that Ni and Co concentrations in peat pore water increased by approximately 530 and 960% for Ni and Co, respectively between spring and summer due to drought-induced acidification, but there was much less change in Cu concentration. Sphagnum cover and (210)Pb activity measured at 10 cm at the 14 sites significantly increased with distance from Copper Cliff, and the surface peat von Post score decreased with distance from Copper Cliff, indicating the rate of peat formation increases with distance from Sudbury presumably as a result of improved Sphagnum survival. This study shows that the ability of peat to preserve deposition histories of some metals is strongly affected by drought-induced post-depositional movement and that loss of Sphagnum due to air pollution impairs the rate of peat formation, further affecting metal profiles in peatlands.

  19. Profile negotiation: An air/ground automation integration concept for managing arrival traffic

    NASA Technical Reports Server (NTRS)

    Williams, David H.; Arbuckle, P. Douglas; Green, Steven M.; Denbraven, Wim

    1993-01-01

    NASA Ames Research Center and NASA Langley Research Center conducted a joint simulation study to evaluate a profile negotiation process (PNP) between a time-based air traffic control ATC system and an airplane equipped with a four dimensional flight management system (4D FMS). Prototype procedures were developed to support the functional implementation of this process. The PNP was designed to provide an arrival trajectory solution that satisfies the separation requirements of ATC while remaining as close as possible to the airplane's preferred trajectory. The Transport Systems Research Vehicle cockpit simulator was linked in real-time to the Center/TRACON Automation System (CTAS) for the experiment. Approximately 30 hours of simulation testing were conducted over a three week period. Active airline pilot crews and active Center controller teams participated as test subjects. Results from the experiment indicate the potential for successful incorporation of airplane preferred arrival trajectories in the CTAS automation environment. Controllers were able to consistently and effectively negotiate nominally conflict-free trajectories with pilots flying a 4D-FMS-equipped airplane. The negotiated trajectories were substantially closer to the airplane's preference than would have otherwise been possible without the PNP. Airplane fuel savings relative to baseline CTAS were achieved in the test scenarios. The datalink procedures and clearances developed for this experiment, while providing the necessary functionality, were found to be operationally unacceptable to the pilots. Additional pilot control and understanding of the proposed airplane-preferred trajectory and a simplified clearance procedure were cited as necessary for operational implementation of the concept. From the controllers' perspective, the main concerns were the ability of the 4D airplane to accurately track the negotiated trajectory and the workload required to support the PNP as implemented in this study.

  20. Drying rate and temperature profile for superheated steam vacuum drying and moist air drying of softwood lumber

    SciTech Connect

    Pang, S.; Dakin, M.

    1999-07-01

    Two charges of green radiata pine sapwood lumber were dried, ether using superheated steam under vacuum (90 C, 0.2 bar abs.) or conventionally using hot moist air (90/60 C). Due to low density of the drying medium under vacuum, the circulation velocity used was 10 m/s for superheated steam drying and 5.0 m/s for moist air drying, and in both cases, the flow was unidirectional. In drying, stack drying rate and wood temperatures were measured to examine the differences between the superheated steam drying and drying using hot moist air. The experimental results have shown that the stack edge board in superheated steam drying dried faster than in the hot moist air drying. Once again due to the low density of the steam under vacuum, a prolonged maximum temperature drop across load (TDAL) was observed in the superheated steam drying, however, the whole stack dried slower and the final moisture content distribution was more variable than for conventional hot moist air drying.

  1. LASER APPLICATIONS IN MEDICINE: Analysis of distortions in the velocity profiles of suspension flows inside a light-scattering medium upon their reconstruction from the optical coherence Doppler tomograph signal

    NASA Astrophysics Data System (ADS)

    Bykov, A. V.; Kirillin, M. Yu; Priezzhev, A. V.

    2005-11-01

    Model signals from one and two plane flows of a particle suspension are obtained for an optical coherence Doppler tomograph (OCDT) by the Monte-Carlo method. The optical properties of particles mimic the properties of non-aggregating erythrocytes. The flows are considered in a stationary scattering medium with optical properties close to those of the skin. It is shown that, as the flow position depth increases, the flow velocity determined from the OCDT signal becomes smaller than the specified velocity and the reconstructed profile extends in the direction of the distant boundary, which is accompanied by the shift of its maximum. In the case of two flows, an increase in the velocity of the near-surface flow leads to the overestimated values of velocity of the reconstructed profile of the second flow. Numerical simulations were performed by using a multiprocessor parallel-architecture computer.

  2. Profiles.

    ERIC Educational Resources Information Center

    School Arts, 1979

    1979-01-01

    Profiles seven Black, Native American, and Chicano artists and art teachers: Hale A. Woodruff, Allan Houser, Luis Jimenez, Betrand D. Phillips, James E. Pate, I, and Fernando Navarro. This article is part of a theme issue on multicultural art. (SJL)

  3. Impact of AIRS Thermodynamic Profiles on Precipitation Forecasts for Atmospheric River Cases Affecting the Western United States

    NASA Technical Reports Server (NTRS)

    Zavodsky, Bradley T.; Jedlovec, Gary J.; Blakenship, Clay B.; Wick, Gary A.; Neiman, Paul J.

    2013-01-01

    This project is a collaborative activity between the NASA Short-term Prediction Research and Transition (SPoRT) Center and the NOAA Hydrometeorology Testbed (HMT) to evaluate a SPoRT Advanced Infrared Sounding Radiometer (AIRS: Aumann et al. 2003) enhanced moisture analysis product. We test the impact of assimilating AIRS temperature and humidity profiles above clouds and in partly cloudy regions, using the three-dimensional variational Gridpoint Statistical Interpolation (GSI) data assimilation (DA) system (Developmental Testbed Center 2012) to produce a new analysis. Forecasts of the Weather Research and Forecasting (WRF) model initialized from the new analysis are compared to control forecasts without the additional AIRS data. We focus on some cases where atmospheric rivers caused heavy precipitation on the US West Coast. We verify the forecasts by comparison with dropsondes and the Cooperative Institute for Research in the Atmosphere (CIRA) Blended Total Precipitable Water product.

  4. Assessment of hematological profiles of adult male athletes from two different air pollutant zones of West Bengal, India.

    PubMed

    Das, Paulomi; Chatterjee, Pinaki

    2015-01-01

    Health effects from air pollution are severe concern of today's world. The study was undertaken to assess the effects of air pollution on hematological profiles of trained and untrained males of West Bengal. The sample consisted of 60 sprinters, 60 footballers, and 120 untrained males, subdivided into two groups from two zones, namely, Tollygunge and Sonarpur. Suspended particulate matter (SPM), respirable particulate matter (RPM), oxides of sulfur (SOx), and oxides of nitrogen (NOx) of ambient air were monitored for both zones. Height and weight of all the subjects were measured. Venous blood sample was drawn from the cubital vein, and the red blood cell count (TC), packed cell volume (PCV), hemoglobin (Hb) concentration, mean corpuscular volume (MCV), and mean corpuscular hemoglobin concentration (MCHC) were determined by standard methods. Results revealed that SPM, RPM, SOx, and NOx concentrations were significantly higher in the Tollygunge area than Sonarpur. TC, PCV, and Hb concentration of untrained males were significantly higher than footballers in both regions but no significant difference were observed when compared with sprinters, except the Hb concentration in the Tollygunge zone. On the other hand, all hematological parameters of both trained and untrained males were significantly higher in the Sonarpur area than Tollygunge. It was concluded that environmental air pollutants might influence hematological profile adversely both in trained and sedentary males. However, further investigation in this area is needed.

  5. Experimental study on copper cathode erosion rate and rotational velocity of magnetically driven arcs in a well-type cathode non-transferred plasma torch operating in air

    NASA Astrophysics Data System (ADS)

    Chau, S. W.; Hsu, K. L.; Lin, D. L.; Tzeng, C. C.

    2007-04-01

    The cathode erosion rate, arc root velocity and output power of a well-type cathode (WTC), non-transferred plasma torch operating in air are studied experimentally in this paper. An external solenoid to generate a magnetically driven arc and a circular swirler to produce a vortex flow structure are equipped in the studied torch system, which is designed to reduce the erosion rate at the cathode. A least square technique is applied to correlate the system parameters, i.e. current, axial magnetic field and mass flow rate, with the cathode erosion rate, arc root velocity and system power output. In the studied WTC torch system, the cathode erosion has a major thermal erosion component and a minor component due to the ion-bombardment effect. The cathode erosion increases with the increase of current due to the enhancement in both Joule heating and ion bombardment. The axial magnetic field can significantly reduce the cathode erosion by reducing the thermal loading of cathode materials at the arc root and improving the heat transfer to gas near the cathode. But, the rise in the mass flow rate leads to the deterioration of erosion, since the ion-bombardment effect prevails over the convective cooling at the cathode. The most dominant system parameter to influence the arc root velocity is the axial magnetic field, which is mainly contributed to the magnetic force driving the arc. The growth in current has a negative impact on increasing the arc root velocity, because the friction force acting at the spot due to a severe molten condition becomes the dominant component counteracting the magnetic force. The mass flow rate also suppresses the arc root velocity, as a result of which the arc root moves in the direction against that of the swirled working gas. All system parameters such as current, magnetic field and gas flow rate increase with the increase in the torch output power. The experimental evidences suggest that the axial magnetic field is the most important parameter

  6. Interpretation of combined wind profiler and aircraft-measured tropospheric winds and clear air turbulence

    NASA Technical Reports Server (NTRS)

    Thomson, D. W.; Syrett, William J.; Fairall, C. W.

    1991-01-01

    In the first experiment, it was found that wind profilers are far better suited for the detailed examination of jet stream structure than are weather balloons. The combination of good vertical resolution with not previously obtained temporal resolution reveals structural details not seen before. Development of probability-derived shear values appears possible. A good correlation between pilot reports of turbulence and wind shear was found. In the second experiment, hourly measurements of wind speed and direction obtained using two wind profiling Doppler radars during two prolonged jet stream occurrences over western Pennsylvania were analyzed. In particular, the time-variant characteristics of derived shear profiles were examined. Profiler data dropouts were studied in an attempt to determine possible reasons for the apparently reduced performance of profiling radar operating beneath a jet stream. Richardson number and wind shear statistics were examined along with pilot reports of turbulence in the vicinity of the profiler.

  7. Investigation of the emissions and profiles of a wide range of VOCs during the Clean air for London project

    NASA Astrophysics Data System (ADS)

    Holmes, Rachel; Lidster, Richard; Hamilton, Jacqueline; Lee, James; Hopkins, James; Whalley, Lisa; Lewis, Alistair

    2014-05-01

    The majority of the World's population live in polluted urbanized areas. Poor air quality is shortening life expectancy of people in the UK by an average 7-8 months and costs society around £20 billion per year.[1] Despite this, our understanding of atmospheric processing in urban environments and its effect on air quality is incomplete. Air quality models are used to predict how air quality changes given different concentrations of pollution precursors, such as volatile organic compounds (VOCs). The urban environment of megacities pose a unique challenge for air quality measurements and modelling, due to high population densities, pollution levels and complex infrastructure. For over 60 years the air quality in London has been monitored, however the existing measurements are limited to a small group of compounds. In order to fully understand the chemical and physical processes that occur in London, more intensive and comprehensive measurements should be made. The Clean air for London (ClearfLo) project was conducted to investigate the air quality, in particular the boundary layer pollution, of London. A relatively new technique, comprehensive two dimensional gas chromatography (GC×GC) [2] was combined with a well-established dual channel GC (DC-GC) [3] system to provide a more comprehensive measurement of VOCs. A total of 78 individual VOCs (36 aliphatics, 19 monoaromatics, 21 oxygenated and 2 halogenated) and 10 groups of VOCs (8 aliphatic, 1 monoaromatic and 1 monoterpene) from C1-C13+ were quantified. Seasonal and diurnal profiles of these VOCs have been found which show the influence of emission source and chemical processing. Including these extra VOCs should enhance the prediction capability of air quality models thus informing policy makers on how to potentially improve air quality in megacities. References 1. House of Commons Environmental Audit Committee, Air Quality: A follow-up report, Ninth Report of session 2012-12. 2. Lidster, R.T., J.F. Hamilton

  8. Transcriptome Profiling of the Lungs Reveals Molecular Clock Genes Expression Changes after Chronic Exposure to Ambient Air Particles

    PubMed Central

    Song, Pengcheng; Li, Zhigang; Li, Xiaoqian; Yang, Lixin; Zhang, Lulu; Li, Nannan; Guo, Chen; Lu, Shuyu; Wei, Yongjie

    2017-01-01

    The symptoms of asthma, breathlessness, insomnia, etc. all have relevance to pulmonary rhythmic disturbances. Epidemiology and toxicology studies have demonstrated that exposure to ambient air particles can result in pulmonary dysfunction. However, there are no data directly supporting a link between air pollution and circadian rhythm disorder. In the present study, we found that breathing highly polluted air resulted in changes of the molecular clock genes expression in lung by transcriptome profiling analyses in a rodent model. Compared to those exposed to filtered air, in both pregnant and offspring rats in the unfiltered group, key clock genes (Per1, Per2, Per3, Rev-erbα and Dbp) expression level decreased and Bmal1 expression level increased. In both rat dams and their offspring, after continuous exposure to unfiltered air, we observed significant histologic evidence for both perivascular and peribronchial inflammation, increased tissue and systemic oxidative stress in the lungs. Our results suggest that chronic exposure to particulate matter can induce alterations of clock genes expression, which could be another important pathway for explaining the feedbacks of ambient particle exposure in addition to oxidative stress and inflammation. PMID:28106813

  9. Gas transfer velocities for quantifying methane, oxygen and other gas fluxes through the air-water interface of wetlands with emergent vegetation

    NASA Astrophysics Data System (ADS)

    Poindexter, C.; Variano, E. A.

    2012-12-01

    Empirical models for the gas transfer velocity, k, in the ocean, lakes and rivers are fairly well established, but there are few data to predict k for wetlands. We have conducted experiments in a simulated emergent marsh in the laboratory to explore the relationship between k, wind shear and thermal convection. Now we identify the implications of these results for gas transfer in actual wetlands by (1) quantifying the range of wind conditions in emergent vegetation canopies and the range of thermal convection intensities in wetland water columns, and (2) describing the non-linear interaction of these two stirring forces over their relevant ranges in wetlands. We measured mean wind speeds and wind speed variance within the shearless region of a Schoenoplectus-Typha marsh canopy in the Sacramento-San Joaquin Delta (Northern California, USA). The mean wind speed within this region, , is significantly smaller than wind above the canopy. Based on our laboratory experiments, for calm or even average wind conditions in this emergent marsh k600 is only on the order 0.1 cm hr-1 (for neutrally or stably stratified water columns). We parameterize unstable thermal stratification and the resulting thermal convection using the heat flux through the air-water interface, q. We analyzed a water temperature record for the Schoenoplectus-Typha marsh to obtain a long-term heat flux record. We used these heat flux data along with short-term heat flux data from other wetlands in the literature to identify the range of the gas transfer velocity associated with thermal convection in wetlands. The typical range of heat fluxes through water columns shaded by closed emergent canopies (-200 W m-2 to +200 W m-2) yields k600 values of 0.5 - 2.5 cm hr-1 according to the model we developed in the laboratory. Thus for calm or average wind conditions, the gas transfer velocity associated with thermal convection is significantly larger than the gas transfer velocity associated with wind

  10. Walk-through survey report: HVLV (high velocity low volume) control technology for aircraft bonded wing and radome maintenance at Air Force Logistics Command, McClellan Air Force Base, Sacramento, California

    SciTech Connect

    Hollett, B.A.

    1983-08-01

    A walk through survey was conducted at the Sacramento Air Logistics Center, McClellan Air Force Base, California, on June 13, 1983, to evaluate the use of High Velocity Low Volume (HVLV) technology in the aircraft-maintenance industry. The HVLV system consisted of 65 ceiling drops in the bonded honeycomb shop where grinding and sanding operations created glass fiber and resin dusts. Preemployment and periodic physical examinations were required. Workers were required to wear disposable coveralls, and disposable dust masks were available. Workers walked through decontamination air jet showers before leaving the area to change clothes. Environmental monitoring revealed no significant dust exposures when the HVLV system was in use. Performance of the exhaust system on the eight-inch-diameter nose cone sanding operation was good, but the three-inch-diameter tools were too large and the shrouds too cumbersome for use on many hand-finishing tasks. The author concludes that the HVLV system is partially successful but requires additional shroud design. Further development of small tool shrouds is recommended.

  11. Making Program Assessment Work: A Profile of the U.S. Air Force Academy.

    ERIC Educational Resources Information Center

    Millis, Barbara J.; Lowe, James K.; Aretz, Anthony J.

    2003-01-01

    Examines the three levels of course and program assessment present at the U.S. Air Force Academy, including assessment at the course, departmental, and institutional levels. Points out common elements useful to all assessment efforts. (EV)

  12. Applications of principal component analysis to breath air absorption spectra profiles classification

    NASA Astrophysics Data System (ADS)

    Kistenev, Yu. V.; Shapovalov, A. V.; Borisov, A. V.; Vrazhnov, D. A.; Nikolaev, V. V.; Nikiforova, O. Y.

    2015-12-01

    The results of numerical simulation of application principal component analysis to absorption spectra of breath air of patients with pulmonary diseases are presented. Various methods of experimental data preprocessing are analyzed.

  13. Velocity and drop size measurements in a confined, swirl-stabilized, combusting spray

    NASA Technical Reports Server (NTRS)

    Bulzan, Daniel L.

    1996-01-01

    Drop size and velocity measurements in a confined, swirl-stabilized, reacting spray are presented. The configuration consisted of a center-mounted research air-assist atomizer surrounded by a coflowing air stream. A quartz tube surrounded the burner and provided the confinement. Both the air-assist and coflow streams had swirl imparted to them in the same direction with 45-degree-angle swirlers. The fuel and air entered the combustor at ambient temperature. The gas-phase measurements reported were obtained from the velocity drops with a mean diameter of four microns. Heptane fuel was used for all the experiments. Measurements of drop size and velocity, gas-phase velocity and drop number flux are reported for axial distances of 23, 5, 10, 15, 25, and 50 mm downstream of the nozzle. The measurements were performed using a two-component phase/Doppler particle analyzer. Profiles across the entire flowfield are presented.

  14. Dissolved methane concentration profiles and air-sea fluxes from 41°S to 27°N

    NASA Astrophysics Data System (ADS)

    Kelley, Cheryl A.; Jeffrey, Wade H.

    2002-07-01

    Water column samples from a transect cruise from southern Chile through the Panama Canal to the Gulf of Mexico were used to determine dissolved methane depth profiles and air-sea methane fluxes. In the Gulf of Mexico, surface concentrations were approximately 40% supersaturated with respect to the atmosphere, whereas near the equator and in the Peru upwelling region, 10-20% supersaturation generally occurred. These saturation ratios translate into an average flux of methane from the sea surface to the atmosphere of 0.38 μmol m-2 d-1. In addition, water column profiles of dissolved methane indicate that subsurface maxima in dissolved methane concentrations are a consistent feature of the open ocean, except near the equator. At the equator, the subsurface peak at the base of the mixed layer may be bowed down by the Equatorial Undercurrent. The highest methane concentration (12 nM) was observed in the Peru upwelling region.

  15. Characterisation of volatile profile and sensory analysis of fresh-cut "Radicchio di Chioggia" stored in air or modified atmosphere.

    PubMed

    Cozzolino, Rosaria; Martignetti, Antonella; Pellicano, Mario Paolo; Stocchero, Matteo; Cefola, Maria; Pace, Bernardo; De Giulio, Beatrice

    2016-02-01

    The volatile profile of two hybrids of "Radicchio di Chioggia", Corelli and Botticelli, stored in air or passive modified atmosphere (MAP) during 12 days of cold storage, was monitored by solid phase micro-extraction (SPME) GC-MS. Botticelli samples were also subjected to sensory analysis. Totally, 61 volatile organic compounds (VOCs) were identified in the headspace of radicchio samples. Principal component analysis (PCA) showed that fresh product possessed a metabolic content similar to that of the MAP samples after 5 and 8 days of storage. Projection to latent structures by partial least squares (PLS) regression analysis showed the volatiles content of the samples varied depending only on the packaging conditions. Specifically, 12 metabolites describing the time evolution and explaining the effects of the different storage conditions were highlighted. Finally, a PCA analysis revealed that VOCs profile significantly correlated with sensory attributes.

  16. Doppler Lidar Vertical Velocity Statistics Value-Added Product

    SciTech Connect

    Newsom, R. K.; Sivaraman, C.; Shippert, T. R.; Riihimaki, L. D.

    2015-07-01

    Accurate height-resolved measurements of higher-order statistical moments of vertical velocity fluctuations are crucial for improved understanding of turbulent mixing and diffusion, convective initiation, and cloud life cycles. The Atmospheric Radiation Measurement (ARM) Climate Research Facility operates coherent Doppler lidar systems at several sites around the globe. These instruments provide measurements of clear-air vertical velocity profiles in the lower troposphere with a nominal temporal resolution of 1 sec and height resolution of 30 m. The purpose of the Doppler lidar vertical velocity statistics (DLWSTATS) value-added product (VAP) is to produce height- and time-resolved estimates of vertical velocity variance, skewness, and kurtosis from these raw measurements. The VAP also produces estimates of cloud properties, including cloud-base height (CBH), cloud frequency, cloud-base vertical velocity, and cloud-base updraft fraction.

  17. Autonomous Observations of the Upper Ocean Stratification and Velocity Fields About the Seasonally-Retreating Marginal Ice Zone. Acquisition of Ice-Tethered Profilers with Velocity (ITP-V) Instruments as a Contribution to the Marginal Ice Zone DRI

    DTIC Science & Technology

    2012-09-30

    ice -ocean interactions in the polar oceans ( Arctic and Southern Ocean). Particular areas of focus include ice -ocean exchanges of momentum, heat and...the manuscript of Cole et al., 2012 (Ekman veering, internal waves, and turbulent fluxes observed under Arctic sea- ice , J. Phys. Oceanogr., in...Observed ocean velocity was primarily directed to the right of ice velocity and spiraled clockwise while decaying with depth through the surface mixed

  18. Improving the air coupling of bulk piezoelectric transducers with wedges of power-law profiles: a numerical study.

    PubMed

    Remillieux, Marcel C; Anderson, Brian E; Le Bas, Pierre-Yves; Ulrich, T J

    2014-07-01

    An air-coupled ultrasonic transducer is created by bonding a bulk piezoelectric element onto the surface of a thick plate with a wedge of power-law profile. The wedge is used to improve the ultrasonic radiation efficiency. The power-law profile provides a smooth, impedance-matching transition for the mechanical energy to be transferred from the thick plate to the air, through the large-amplitude flexural waves observed in the thinnest region of the wedge. The performance of the proposed transducer is examined numerically and compared to that of a design where the piezoelectric element is isolated and where it is affixed to a thin plate of uniform thickness. The numerical analysis is first focused on the free-field radiation of the transducers. Then, time-reversal experiments are simulated by placing the transducers inside a cavity of arbitrary shape with some perfectly reflecting boundaries. In addition to time-reversal mirrors, the proposed concept could be integrated in the design of phased arrays and parametric arrays.

  19. SYSTEMIC BIOMARKERS AND CARDIAC GENE EXPRESSION PROFILES OF RAT DISEASE MODELS EMPLOYED IN AIR POLLUTION STUDIES

    EPA Science Inventory

    Cardiovascular disease (CVD) models are used for identification of mechanisms of susceptibility to air pollution. We hypothesized that baseline systemic biomarkers and cardiac gene expression in CVD rat models will have influence on their ozone-induced lung inflammation. Male 12-...

  20. Regional Data Assimilation of AIRS Profiles and Radiances at the SPoRT Center

    NASA Technical Reports Server (NTRS)

    Zavodsky, Brad; Chou, Shih-hung; Jedlovec, Gary

    2009-01-01

    This slide presentation reviews the Short Term Prediction Research and Transition (SPoRT) Center's mission to improve short-term weather prediction at the regional and local scale. It includes information on the cold bias in Weather Research and Forcasting (WRF), troposphere recordings from the Atmospheric Infrared Sounder (AIRS), and vertical resolution of analysis grid.

  1. Heating, Ventilation, Air-Conditioning, and Refrigeration. Occupational Competency Analysis Profile.

    ERIC Educational Resources Information Center

    Ohio State Univ., Columbus. Vocational Instructional Materials Lab.

    This Occupational Competency Analysis Profile (OCAP) contains a competency list verified by expert workers and developed through a modified DACUM (Developing a Curriculum) involving business, industry, labor, and community agency representatives from Ohio. This OCAP identifies the occupational, academic, and employability skills (competencies)…

  2. Full-Scale Propeller Disk Wake Survey and Boundary Layer Velocity Profile Measurements on the 154-Foot Ship R/V Athena

    DTIC Science & Technology

    1980-09-01

    TABLES ............. ........................... ix NOTATION ........ ..... ............................... x ABSTRACT...Pressure r/R or x Radius or RIO. Distance (r) from the propeller axis expressed as a ratio of the propeller radius (R) R R Reynolds number n n RI, R2 RI, R2...longitudinal velocity measured by means of boundary layer pitot tubes V V Actual model or ship velocity Vb( x ,e) --- Resultant inflow velocity to

  3. A novel multi-beam correlation lidar for wind profiling and plume tracking for air quality applications

    NASA Astrophysics Data System (ADS)

    Prasad, N. S.

    2014-12-01

    Various types of in-situ and remote sensing techniques are being utilized for measuring air quality parameters. In this paper, the development and testing of a novel three beam multifunctional direct detection lidar for air quality applications will be discussed. Operating at 1030 nm wavelength, this lidar is a nanosecond class direct detection system with three transceivers and is capable of tracking the motion of aerosol structures using elastic backscatter. Designed with scalable and modular elements and advanced algorithms and graphical user display, this lidar is tripod mounted and measures three component (3D) winds by cross correlation of aerosol backscatter from three near-parallel beams. Besides extracting multi-component wind data, the system is designed provide various atmospheric elements including turbulence. Performance of this lidar in regard to crosswind profiling has been validated with ultrasonic anemometers under low and high wind conditions. From the field data, it shown that this lidar is capable of providing relatively high spatial resolution (<1.2 m) and line-of-sight error less than 0.1 m/s over a range of greater than 2 km. With a maximum operational range of over 15 km, this lidar was recently used to study effluents from a smokestack. The results of our plume tracking study will be presented and follow-on applications for studying air emissions due to hydraulic fracturing or fracking, will be discussed.

  4. Effect of gas-transfer velocity parameterization choice on air-sea CO2 fluxes in the North Atlantic Ocean and the European Arctic

    NASA Astrophysics Data System (ADS)

    Wrobel, Iwona; Piskozub, Jacek

    2016-09-01

    The oceanic sink of carbon dioxide (CO2) is an important part of the global carbon budget. Understanding uncertainties in the calculation of this net flux into the ocean is crucial for climate research. One of the sources of the uncertainty within this calculation is the parameterization chosen for the CO2 gas-transfer velocity. We used a recently developed software toolbox, called the FluxEngine (Shutler et al., 2016), to estimate the monthly air-sea CO2 fluxes for the extratropical North Atlantic Ocean, including the European Arctic, and for the global ocean using several published quadratic and cubic wind speed parameterizations of the gas-transfer velocity. The aim of the study is to constrain the uncertainty caused by the choice of parameterization in the North Atlantic Ocean. This region is a large oceanic sink of CO2, and it is also a region characterized by strong winds, especially in winter but with good in situ data coverage. We show that the uncertainty in the parameterization is smaller in the North Atlantic Ocean and the Arctic than in the global ocean. It is as little as 5 % in the North Atlantic and 4 % in the European Arctic, in comparison to 9 % for the global ocean when restricted to parameterizations with quadratic wind dependence. This uncertainty becomes 46, 44, and 65 %, respectively, when all parameterizations are considered. We suggest that this smaller uncertainty (5 and 4 %) is caused by a combination of higher than global average wind speeds in the North Atlantic (> 7 ms-1) and lack of any seasonal changes in the direction of the flux direction within most of the region. We also compare the impact of using two different in situ pCO2 data sets (Takahashi et al. (2009) and Surface Ocean CO2 Atlas (SOCAT) v1.5 and v2.0, for the flux calculation. The annual fluxes using the two data sets differ by 8 % in the North Atlantic and 19 % in the European Arctic. The seasonal fluxes in the Arctic computed from the two data sets disagree with each

  5. Physical activity profile of 2014 FIFA World Cup players, with regard to different ranges of air temperature and relative humidity

    NASA Astrophysics Data System (ADS)

    Chmura, Paweł; Konefał, Marek; Andrzejewski, Marcin; Kosowski, Jakub; Rokita, Andrzej; Chmura, Jan

    2016-09-01

    The present study attempts to assess changes in soccer players' physical activity profiles under the simultaneous influence of the different combinations of ambient temperature and relative humidity characterising matches of the 2014 FIFA World Cup hosted by Brazil. The study material consisted of observations of 340 players representing 32 national teams taking part in the tournament. The measured indices included total distances covered; distances covered with low, moderate, or high intensity; numbers of sprints performed, and peak running speeds achieved. The analysis was carried out using FIFA official match data from the Castrol Performance Index system. Ultimately, consideration was given to a combination of three air temperature ranges, i.e. below 22 °C, 22-28 °C, and above 28 °C; and two relative humidity ranges below 60 % and above 60 %. The greatest average distance recorded (10.54 ± 0.91 km) covered by players at an air temperature below 22 °C and a relative humidity below 60 %, while the shortest (9.83 ± 1.08 km) characterised the same air temperature range, but conditions of relative humidity above 60 % (p ≤ 0.001). Two-way ANOVA revealed significant differences (p ≤ 0.001) in numbers of sprints performed by players, depending on whether the air temperature range was below 22 °C (40.48 ± 11.17) or above 28 °C (30.72 ± 9.40), but only where the relative humidity was at the same time below 60 %. Results presented indicate that the conditions most comfortable for physical activity on the part of players occur at 22 °C, and with relative humidity under 60 %.

  6. Physical activity profile of 2014 FIFA World Cup players, with regard to different ranges of air temperature and relative humidity.

    PubMed

    Chmura, Paweł; Konefał, Marek; Andrzejewski, Marcin; Kosowski, Jakub; Rokita, Andrzej; Chmura, Jan

    2017-04-01

    The present study attempts to assess changes in soccer players' physical activity profiles under the simultaneous influence of the different combinations of ambient temperature and relative humidity characterising matches of the 2014 FIFA World Cup hosted by Brazil. The study material consisted of observations of 340 players representing 32 national teams taking part in the tournament. The measured indices included total distances covered; distances covered with low, moderate, or high intensity; numbers of sprints performed, and peak running speeds achieved. The analysis was carried out using FIFA official match data from the Castrol Performance Index system. Ultimately, consideration was given to a combination of three air temperature ranges, i.e. below 22 °C, 22-28 °C, and above 28 °C; and two relative humidity ranges below 60 % and above 60 %. The greatest average distance recorded (10.54 ± 0.91 km) covered by players at an air temperature below 22 °C and a relative humidity below 60 %, while the shortest (9.83 ± 1.08 km) characterised the same air temperature range, but conditions of relative humidity above 60 % (p ≤ 0.001). Two-way ANOVA revealed significant differences (p ≤ 0.001) in numbers of sprints performed by players, depending on whether the air temperature range was below 22 °C (40.48 ± 11.17) or above 28 °C (30.72 ± 9.40), but only where the relative humidity was at the same time below 60 %. Results presented indicate that the conditions most comfortable for physical activity on the part of players occur at 22 °C, and with relative humidity under 60 %.

  7. Hydrokinetic canal measurements: inflow velocity, wake flow velocity, and turbulence

    SciTech Connect

    Gunawan, Budi

    2014-06-11

    The dataset consist of acoustic Doppler current profiler (ADCP) velocity measurements in the wake of a 3-meter diameter vertical-axis hydrokinetic turbine deployed in Roza Canal, Yakima, WA, USA. A normalized hub-centerline wake velocity profile and two cross-section velocity contours, 10 meters and 20 meters downstream of the turbine, are presented. Mean velocities and turbulence data, measured using acoustic Doppler velocimeter (ADV) at 50 meters upstream of the turbine, are also presented. Canal dimensions and hydraulic properties, and turbine-related information are also included.

  8. Light propagation characteristics in photonic crystal fibers with α-power profiles of air hole diameter distributions and their application to fiber collimator

    NASA Astrophysics Data System (ADS)

    Yokota, Hirohisa; Higuchi, Keiichi; Imai, Yoh

    2016-08-01

    Light propagation characteristics in photonic crystal fibers (PCFs) with α-power profiles of air hole diameter distributions were theoretically investigated. It was clarified that the intensity peak of the beam propagating in the PCF with Gaussian beam excitation varied periodically with little power attenuation. It was found that the envelope of the periodic intensity variation depended on α. We theoretically demonstrated that the PCF with the α-power profile of the air hole diameter distribution could be applied to a collimator for a conventional PCF with uniform air holes in Gaussian beam excitation to reduce coupling loss, where a PCF of appropriate length with the α-power air hole diameter distribution was spliced to a conventional PCF. It was also found that the coupling efficiency was higher for a larger α.

  9. STEP - A temperature profiler for measuring the oceanic thermal boundary layer at the ocean-air interface

    SciTech Connect

    Mammen, T.C.; Von bosse, N. Salzgitter Elektronik GmbH, Flintbek, )

    1990-04-01

    A fast measuring system has been designed and built to determine the oceanic thermal microstructure at the ocean-air interface. The system consists of a profiler sonde, which ascends through the uppermost few meters of the ocean with a speed of typically 1 m/s and carries a fast temperature sensor with a time constant of 0.5 ms and a surface detector. The data rate is 8000 measurements per second and the achieved resolution in temperature is 0.01 K. The instrument has been designed for rough off-shore treatment and to avoid any disturbance of the boundary layer during measurements. Some measurements of the cool skin are shown from in situ experiments. 26 refs.

  10. Technical note: Update on response times, in-air measurements, and in situ drift for oxygen optodes on profiling platforms

    NASA Astrophysics Data System (ADS)

    Bittig, Henry C.; Körtzinger, Arne

    2017-01-01

    Oxygen optode measurements on floats and gliders suffer from a slow time response and various sources of drift in the calibration coefficients. Based on two dual-O2 Argo floats, we show how to post-correct for the effect of the optode's time response and give an update on optode in situ drift stability and in-air calibration. Both floats are equipped with an unpumped Aanderaa 4330 optode and a pumped Sea-Bird SBE63 optode. Response times for the pumped SBE63 were derived following Bittig et al. (2014) and the same methods were used to correct the time response bias. Using both optodes on each float, the time response regime of the unpumped Aanderaa optode was characterized more accurately than previously possible. Response times for the pumped SBE63 on profiling floats are in the range of 25-40 s, while they are between 60 and 95 s for the unpumped 4330 optode. Our parameterization can be employed to post-correct the slow optode time response on floats and gliders. After correction, both sensors agree to within 2-3 µmol kg-1 (median difference) in the strongest gradients (120 µmol kg-1 change over 8 min or 20 dbar) and better elsewhere. However, time response correction is only possible if measurement times are known, i.e., provided by the platform as well as transmitted and stored with the data. The O2 in-air measurements show a significant in situ optode drift of -0.40 and -0.27 % yr-1 over the available 2 and 3 years of deployment, respectively. Optode in-air measurements are systematically biased high during midday surfacings compared to dusk, dawn, and nighttime. While preference can be given to nighttime surfacings to avoid this in-air calibration bias, we suggest a parameterization of the daytime effect as a function of the Sun's elevation to be able to use all data and to better constrain the result. Taking all effects into account, calibration factors have an uncertainty of 0.1 %. In addition, in-air calibration factors vary by 0.1-0.2 % when using

  11. The Potential of The Synergy of Sunphotometer and Lidar Data to Validate Vertical Profiles of The Aerosol Mass Concentration Estimated by An Air Quality Model

    NASA Astrophysics Data System (ADS)

    Siomos, N.; Filioglou, M.; Poupkou, A.; Liora, N.; Dimopoulos, S.; Melas, D.; Chaikovsky, A.; Balis, D. S.

    2016-06-01

    Vertical profiles of the aerosol mass concentration derived by the Lidar/Radiometer Inversion Code (LIRIC), that uses combined sunphotometer and lidar data, were used in order to validate the aerosol mass concentration profiles estimated by the air quality model CAMx. Lidar and CIMEL measurements performed at the Laboratory of Atmospheric Physics of the Aristotle University of Thessaloniki, Greece (40.5N, 22.9E) from the period 2013-2014 were used in this study.

  12. Major Upgrades to the AIRS Version-6 Water Vapor Profile Methodology

    NASA Technical Reports Server (NTRS)

    Susskind, Joel; Blaisdell, John; Iredell, Lena; Lee, Jae N.

    2015-01-01

    Additional changes in Version-6.19 include all previous updates made to the q(p) retrieval since Version-6: Modified Neural-Net q0(p) guess above the tropopause Linearly tapers the neural net guess to match climatology at 70 mb, not at the top of the atmosphereChanged the 11 trapezoid q(p) perturbation functions used in Version-6 so as to match the 24 functions used in T(p) retrieval step. These modifications resulted in improved water vapor profiles in Version-6.19 compared to Version-6.Version-6.19 is tested for all of August 2013 and August 2014, as well for select other days. Before finalized and operational in 2016, the V-6.19 can be acquired upon request for limited time intervals.

  13. A Comparison of the Red Green Blue (RGB) Air Mass Imagery and Hyperspectral Infrared Retrieved Profiles and NOAA G-IV Dropsondes

    NASA Technical Reports Server (NTRS)

    Berndt, Emily; Folmer, Michael; Dunion, Jason

    2014-01-01

    RGB air mass imagery is derived from multiple channels or paired channel differences. The combination of channels and channel differences means the resulting imagery does not represent a quantity or physical parameter such as brightness temperature in conventional single channel imagery. Without a specific quantity to reference, forecasters are often confused as to what RGB products represent. Hyperspectral infrared retrieved profiles and NOAA G-IV dropsondes provide insight about the vertical structure of the air mass represented on the RGB air mass imagery and are a first step to validating the imagery.

  14. Temperature and Humidity Profiles in the TqJoint Data Group of AIRS Version 6 Product for the Climate Model Evaluation

    NASA Technical Reports Server (NTRS)

    Ding, Feng; Fang, Fan; Hearty, Thomas J.; Theobald, Michael; Vollmer, Bruce; Lynnes, Christopher

    2014-01-01

    The Atmospheric Infrared Sounder (AIRS) mission is entering its 13th year of global observations of the atmospheric state, including temperature and humidity profiles, outgoing long-wave radiation, cloud properties, and trace gases. Thus AIRS data have been widely used, among other things, for short-term climate research and observational component for model evaluation. One instance is the fifth phase of the Coupled Model Intercomparison Project (CMIP5) which uses AIRS version 5 data in the climate model evaluation. The NASA Goddard Earth Sciences Data and Information Services Center (GES DISC) is the home of processing, archiving, and distribution services for data from the AIRS mission. The GES DISC, in collaboration with the AIRS Project, released data from the version 6 algorithm in early 2013. The new algorithm represents a significant improvement over previous versions in terms of greater stability, yield, and quality of products. The ongoing Earth System Grid for next generation climate model research project, a collaborative effort of GES DISC and NASA JPL, will bring temperature and humidity profiles from AIRS version 6. The AIRS version 6 product adds a new "TqJoint" data group, which contains data for a common set of observations across water vapor and temperature at all atmospheric levels and is suitable for climate process studies. How different may the monthly temperature and humidity profiles in "TqJoint" group be from the "Standard" group where temperature and water vapor are not always valid at the same time? This study aims to answer the question by comprehensively comparing the temperature and humidity profiles from the "TqJoint" group and the "Standard" group. The comparison includes mean differences at different levels globally and over land and ocean. We are also working on examining the sampling differences between the "TqJoint" and "Standard" group using MERRA data.

  15. Is there any association between imidapril hydrochloride stability profile under dry air conditions and cancer initiation?

    PubMed

    Regulska, Katarzyna; Murias, Marek; Stanisz, Beata; Regulski, Miłosz

    2013-11-18

    Stability study for imidapril hydrochloride (IMD) was performed under stress conditions of increased temperature (T=373 K) and decreased relative air humidity (RH=0%) in order to obtain and identify its degradation product. The degradation sample stored for 15 days under the above environmental conditions was analyzed by LC-MS technique and it was found that the only degradation impurity formed in the course of the investigated drug degradation was IMD diketopiperazine derivative (DKP) which was produced by dehydration and intramolecular cyclization. The kinetics of its formation was analyzed by a revalidated RP-HPLC method and the kinetic model of this reaction was established. It was concluded that the DKP formation follows Prout-Tompkins kinetics with the rate constant k±Δk=2.034±0.157×10(-6) [s(-1)]. The obtained degradation impurity was further assessed with respect to its mutagenic potential using commercial Ames MPF 98/100 microplate format mutagenicity assay kit equipped with Salmonella typhimurium strains TA 98 and TA 100. Both strains were exposed to six concentrations (in a range of 0.16-5.0mg/mL) of DKP in the presence and absence of metabolic activation system. No mutagenic effect was observed confirming that the presence of DKP in IMD final dosage form has no impact on cancer initiation.

  16. An improved version of the extended velocity-azimuth display analysis of single-Doppler radar data

    NASA Astrophysics Data System (ADS)

    Matejka, Thomas; Srivastava, Ramesh C.

    1991-08-01

    Extended velocity-azimuth display (EVAD) analysis is useful for obtaining vertical profiles of horizontal divergence, vertical air velocity, vertical hydrometer velocity, and hydrometeor terminal fall speed in widespread precipitation. The technique uses a volume of velocity data collected with a single Doppler radar. Several improvements to the previously reported EVAD technique are discussed. They include the weighting of Fourier series coefficients to reflect their estimated error, a correction for heteroscedasticity (the systematic variation of residuals) in the regression analysis, and the weighting of data from different elevation angles to compensate for the finite thickness of the layers in which each analysis is performed. Vertical air velocity is obtained through a variational procedure. Procedures for dealiasing the velocity data and for rejecting outliers from the dataset are summarized. Recommendations for collecting radar data for use in EVAD analysis are made.

  17. In situ evaluation of air-sea CO2 gas transfer velocity in an inner estuary using eddy covariance - with a special focus on the importance of using reliable CO2-fluxes

    NASA Astrophysics Data System (ADS)

    Jørgensen, E. T.; Sørensen, L. L.; Jensen, B.; Sejr, M. K.

    2012-04-01

    The air-sea exchange of CO2 or CO2 flux is driven by the difference in the partial pressure of CO2 in the water and the atmosphere (ΔpCO2), the solubility of CO2 (K0) and the gas transfer velocity (k) (Wanninkhof et al., 2009;Weiss, 1974) . ΔpCO2 and K0 are determined with relatively high precision and it is estimated that the biggest uncertainty when modelling the air-sea flux is the parameterization of k. As an example; the estimated global air-sea flux increases by 70 % when using the parameterization by Wanninkhof and McGillis (1999) instead of Wanninkhof (1992) (Rutgersson et al., 2008). In coastal areas the uncertainty is even higher and only few studies have focused on determining transfer velocity for the coastal waters and even fewer on estuaries (Borges et al., 2004;Rutgersson et al., 2008). The transfer velocity (k600) of CO2 in the inner estuary of Roskilde Fjord, Denmark was investigated using eddy covariance CO2 fluxes (ECM) and directly measured ΔpCO2 during May and June 2010. The data was strictly sorted to heighten the certainty of the results and the outcome was; DS1; using only ECM, and DS2; including the inertial dissipation method (IDM). The inner part of Roskilde Fjord showed to be a very biological active CO2 sink and preliminary results showed that the average k600 was more than 10 times higher than transfer velocities from similar studies of other coastal areas. The much higher transfer velocities were estimated to be caused by the greater fetch and shallower water in Roskilde Fjord, which indicated that turbulence in both air and water influence k600. The wind speed parameterization of k600 using DS1 showed some scatter but when including IDM the r2 of DS2 reached 0.93 with an exponential parameterization, where U10 was based on the Businger-Dyer relationships using friction velocity and atmospheric stability. This indicates that some of the uncertainties coupled with CO2 fluxes calculated by the ECM are removed when including the IDM.

  18. Using High and Low Resolution Profiles of CO2 and CH4 Measured with AirCores to Evaluate Transport Models and Atmospheric Columns Retrieved from Space

    NASA Astrophysics Data System (ADS)

    Membrive, O.; Crevoisier, C. D.; Sweeney, C.; Hertzog, A.; Danis, F.; Picon, L.; Engel, A.; Boenisch, H.; Durry, G.; Amarouche, N.

    2015-12-01

    Over the past decades many methods have been developed to monitor the evolution of greenhouse gases (GHG): ground networks (NOAA, ICOS, TCCON), aircraft campaigns (HIPPO, CARIBIC, Contrail…), satellite observations (GOSAT, IASI, AIRS…). Nevertheless, precise and regular vertical profile measurements are currently still missing from the observing system. To address this need, an original and innovative atmospheric sampling system called AirCore has been developed at NOAA (Karion et al. 2010). This new system allows balloon measurements of GHG vertical profiles from the surface up to 30 km. New versions of this instrument have been developed at LMD: a high-resolution version "AirCore-HR" that differs from other AirCores by its high vertical resolution and two "light" versions (lower resolution) aiming to be flown under meteorological balloon. LMD AirCores were flown on multi-instrument gondolas along with other independent instruments measuring CO2 and CH4 in-situ during the Strato Science balloon campaigns operated by the French space agency CNES in collaboration with the Canadian Space Agency in Timmins (Ontario, Canada) in August 2014 and 2015. First, we will present comparisons of the vertical profiles retrieved with various AirCores (LMD and Frankfurt University) to illustrate repeatability and impact of the vertical resolution as well as comparisons with independent in-situ measurements from other instruments (laser diode based Pico-SDLA). Second, we will illustrate the usefulness of AirCore measurements in the upper troposphere and stratosphere for validating and interpreting vertical profiles from atmospheric transport models as well as observations of total and partial column of methane and carbon dioxide from several current and future spaceborne missions such as: ACE-FTS, IASI and GOSAT.

  19. General instability criterion of laminar velocity distributions

    NASA Technical Reports Server (NTRS)

    Tollmien, W

    1936-01-01

    The present paper describes the results of a stability investigation on symmetrical velocity profiles in a channel and of boundary-layer profiles. The effect of friction was assumed to be vanishing and did not occur in the stability consideration so far as it had been resorted to for preparatory asymptotic considerations. Proceeding on very general premises as regards the form of the velocity distribution, a proof was deduced of the elementary theorem that velocity profiles with inflection points are unstable.

  20. Characterization and source profiling of volatile organic compounds in indoor air of private residences in Selangor State, Malaysia.

    PubMed

    Sakai, Nobumitsu; Yamamoto, Shuta; Matsui, Yasuto; Khan, Md Firoz; Latif, Mohd Talib; Ali Mohd, Mustafa; Yoneda, Minoru

    2017-05-15

    Volatile Organic Compounds (VOCs) in indoor air were investigated at 39 private residences in Selangor State, Malaysia to characterize the indoor air quality and to identify pollution sources. Twenty-two VOCs including isomers (14 aldehydes, 5 aromatic hydrocarbons, acetone, trichloroethylene and tetrachloroethylene) were collected by 2 passive samplers for 24h and quantitated using high performance liquid chromatography and gas chromatography mass spectrometry. Source profiling based on benzene/toluene ratio as well as statistical analysis (cluster analysis, bivariate correlation analysis and principal component analysis) was performed to identify pollution sources of the detected VOCs. The VOCs concentrations were compared with regulatory limits of air quality guidelines in WHO/EU, the US, Canada and Japan to clarify the potential health risks to the residents. The 39 residences were classified into 2 groups and 2 ungrouped residences based on the dendrogram in the cluster analysis. Group 1 (n=30) had mainly toluene (6.87±2.19μg/m(3)), formaldehyde (16.0±10.1μg/m(3)), acetaldehyde (5.35±4.57μg/m(3)) and acetone (11.1±5.95μg/m(3)) at background levels. Group 2 (n=7) had significantly high values of formaldehyde (99.3±10.7μg/m(3)) and acetone (35.8±12.6μg/m(3)), and a tendency to have higher values of acetaldehyde (23.7±13.5μg/m(3)), butyraldehyde (3.35±0.41μg/m(3)) and isovaleraldehyde (2.30±0.39μg/m(3)). The 2 ungrouped residences showed particularly high concentrations of BTX (benzene, toluene and xylene: 235μg/m(3) in total) or acetone (133μg/m(3)). The geometric mean value of formaldehyde (19.2μg/m(3)) exceeded an 8-hour regulatory limit in Canada (9μg/m(3)), while those in other compounds did not exceed any regulatory limits, although a few residences exceeded at least one regulatory limit of benzene or acetaldehyde. Thus, the VOCs in the private residences were effectively characterized from the limited number of monitoring, and the

  1. A profile of volatile organic compounds in exhaled air as a potential non-invasive biomarker for liver cirrhosis

    PubMed Central

    Pijls, Kirsten E.; Smolinska, Agnieszka; Jonkers, Daisy M. A. E.; Dallinga, Jan W.; Masclee, Ad A. M.; Koek, Ger H.; van Schooten, Frederik-Jan

    2016-01-01

    Early diagnosis of liver cirrhosis may prevent progression and development of complications. Liver biopsy is the current standard, but is invasive and associated with morbidity. We aimed to identify exhaled volatiles within a heterogeneous group of chronic liver disease (CLD) patients that discriminates those with compensated cirrhosis (CIR) from those without cirrhosis, and compare this with serological markers. Breath samples were collected from 87 CLD and 34 CIR patients. Volatiles in exhaled air were measured by gas chromatography mass spectrometry. Discriminant Analysis was performed to identify the optimal panel of serological markers and VOCs for classifying our patients using a random training set of 27 CIR and 27 CLD patients. Two randomly selected independent internal validation sets and permutation test were used to validate the model. 5 serological markers were found to distinguish CIR and CLD patients with a sensitivity of 0.71 and specificity of 0.84. A set of 11 volatiles discriminated CIR from CLD patients with sensitivity of 0.83 and specificity of 0.87. Combining both did not further improve accuracy. A specific exhaled volatile profile can predict the presence of compensated cirrhosis among CLD patients with a higher accuracy than serological markers and can aid in reducing liver biopsies. PMID:26822454

  2. Study of azo dye decolorization and determination of cathode microorganism profile in air-cathode microbial fuel cells.

    PubMed

    Kumru, Mert; Eren, Hilal; Catal, Tunc; Bermek, Hakan; Akarsubaşi, Alper Tunga

    2012-09-01

    Five textile azo dyes, as part of an artificial mixture, were treated in single-chamber air-cathode microbial fuel cells while simultaneously utilizing acetate for electricity production. Remazol Black, Remazol Brilliant Blue, Remazol Turquoise Blue, Reactive Yellow and Reactive Red at concentrations of 40 or 80 mg L(-1) were decolorized to a similar extent, at averages of 78, 95, 53, 93 and 74%, respectively, in 24 hours. During the process of decolorization, electricity generation from acetate oxidation continued. Power densities obtained in the presence of textile dyes ranged from 347 to 521 mW m(-2) at the current density range of 0.071 - 0.086 mA cm(-2). Microbial community analyses of cathode biofilm exhibited dynamic changes in abundant species following dye decolorization. Upon the addition of the first dye, a major change (63%) in microbial diversity was observed; however, subsequent addition of other dyes did not affect the community profile significantly. Actinobacteria, Aquamicrobium, Mesorhizobium, Ochrobactrum, Thauera, Paracoccus, Achromobacter and Chelatacoccus affiliated phylotypes were the major phylotypes detected. Our results demonstrate that microbial fuel cells could be a promising alternative for treatment of textile wastewaters and an active bacterial community can rapidly be established for simultaneous azo dye decolorization and sustainable electricity generation.

  3. Velocity Dispersions Across Bulge Types

    SciTech Connect

    Fabricius, Maximilian; Bender, Ralf; Hopp, Ulrich; Saglia, Roberto; Drory, Niv; Fisher, David

    2010-06-08

    We present first results from a long-slit spectroscopic survey of bulge kinematics in local spiral galaxies. Our optical spectra were obtained at the Hobby-Eberly Telescope with the LRS spectrograph and have a velocity resolution of 45 km/s (sigma*), which allows us to resolve the velocity dispersions in the bulge regions of most objects in our sample. We find that the velocity dispersion profiles in morphological classical bulge galaxies are always centrally peaked while the velocity dispersion of morphologically disk-like bulges stays relatively flat towards the center--once strongly barred galaxies are discarded.

  4. Influence of air-staging on the concentration profiles of NH{sub 3} and HCN in the combustion chamber of a CFB boiler burning coal

    SciTech Connect

    Kassman, H.; Karlsson, M.; Aamand, L.E.

    1999-07-01

    The characterization of the concentration profiles of NH{sub 3} and HCN are of great importance for increasing the knowledge of the formation and destruction pathways of NO and N{sub 2}O in a fluidized bed boiler. Further improvements of the sampling methods for the determination of both NH{sub 3} and HCN in the combustion chamber in full-scale CFB boilers are also needed. A gas-sampling probe connected to a Fourier Transform Infrared (FTIR) instrument and a gas-quenching (GQ) probe in which the sample is quenched directly in the probe tip by a circulating trapper solution were used. The FTIR technique is based on analysis of hot combustion gases, whereas the trapper solutions from the GQ probe were analyzed by means of wet chemistry. The tests were performed during coal combustion in a 12 MW CFB boiler, which was operated at three air-staging cases with the addition of limestone for sulfur capture. The concentration profiles of NH{sub 3} and HCN in the combustion chamber showed a different pattern concerning the influence of air-staging. The highest levels of NH{sub 3} were observed during reducing condition (severe air-staging), and the lowest were found under oxidizing conditions (no air-staging). The levels of HCN were much lower than those measured for NH{sub 3}. The highest levels of HCN were observed for reversed air-staging and severe air-staging showed almost no HCN. The potential reactors involving NH{sub 3} and HCN in the combustion chamber as well as the potential measurement errors in each sampling technique are discussed for the three air-staging cases.

  5. ON THE DOPPLER VELOCITY OF EMISSION LINE PROFILES FORMED IN THE 'CORONAL CONTRAFLOW' THAT IS THE CHROMOSPHERE-CORONA MASS CYCLE

    SciTech Connect

    McIntosh, Scott W.; Tian Hui; Sechler, Marybeth; De Pontieu, Bart

    2012-04-10

    This analysis begins to explore the complex chromosphere-corona mass cycle using a blend of imaging and spectroscopic diagnostics. Single Gaussian fits (SGFs) to hot emission line profiles (formed above 1 MK) at the base of coronal loop structures indicate material blueshifts of 5-10 km s{sup -1}, while cool emission line profiles (formed below 1 MK) yield redshifts of a similar magnitude-indicating, to zeroth order, that a temperature-dependent bifurcating flow exists on coronal structures. Image sequences of the same region reveal weakly emitting upward propagating disturbances in both hot and cool emission with apparent speeds of 50-150 km s{sup -1}. Spectroscopic observations indicate that these propagating disturbances produce a weak emission component in the blue wing at commensurate speed, but that they contribute only a few percent to the (ensemble) emission line profile in a single spatio-temporal resolution element. Subsequent analysis of imaging data shows material 'draining' slowly ({approx}10 km s{sup -1}) out of the corona, but only in the cooler passbands. We interpret the draining as the return flow of coronal material at the end of the complex chromosphere-corona mass cycle. Further, we suggest that the efficient radiative cooling of the draining material produces a significant contribution to the red wing of cool emission lines that is ultimately responsible for their systematic redshift as derived from an SGF when compared to those formed in hotter (conductively dominated) domains. The presence of counterstreaming flows complicates the line profiles, their interpretation, and asymmetry diagnoses, but allows a different physical picture of the lower corona to develop.

  6. Data Assimilation of AIRS Water Vapor Profiles: Impact on Precipitation Forecasts for Atmospheric River Cases Affecting the Western of the United States

    NASA Technical Reports Server (NTRS)

    Blankenship, Clay; Zavodsky, Bradley; Jedlovec, Gary; Wick, Gary; Neiman, Paul

    2013-01-01

    Atmospheric rivers are transient, narrow regions in the atmosphere responsible for the transport of large amounts of water vapor. These phenomena can have a large impact on precipitation. In particular, they can be responsible for intense rain events on the western coast of North America during the winter season. This paper focuses on attempts to improve forecasts of heavy precipitation events in the Western US due to atmospheric rivers. Profiles of water vapor derived from from Atmospheric Infrared Sounder (AIRS) observations are combined with GFS forecasts by a three-dimensional variational data assimilation in the Gridpoint Statistical Interpolation (GSI). Weather Research and Forecasting (WRF) forecasts initialized from the combined field are compared to forecasts initialized from the GFS forecast only for 3 test cases in the winter of 2011. Results will be presented showing the impact of the AIRS profile data on water vapor and temperature fields, and on the resultant precipitation forecasts.

  7. Decomposing the profile of PM in two low polluted German cities--mapping of air mass residence time, focusing on potential long range transport impacts.

    PubMed

    Dimitriou, Konstantinos; Kassomenos, Pavlos

    2014-07-01

    This paper aims to decompose the profile of particulates in Karlsruhe and Potsdam (Germany), focusing on the localization of PM potential transboundary sources. An air mass cluster analysis was implemented, followed by a study of air mass residence time on a grid of a 0.5° × 0.5° resolution. Particulate/gaseous daily air pollution and meteorological data were used to indicate PM local sources. Four Principal Component Analysis (PCA) components were produced: traffic, photochemical, industrial/domestic and particulate. PM2.5/PM10 ratio seasonal trends, indicated production of PMCOARSE (PM10-PM2.5) from secondary sources in Potsdam during warm period (WP). The residing areas of incoming slow moving air masses are potential transboundary PM sources. For Karlsruhe those areas were mainly around the city. An air mass residence time secondary peak was observed over Stuttgart. For Potsdam, areas with increased dwelling time of the arriving air parcels were detected particularly above E/SE Germany.

  8. A shift in emission time profiles of fossil fuel combustion due to energy transitions impacts source receptor matrices for air quality.

    PubMed

    Hendriks, Carlijn; Kuenen, Jeroen; Kranenburg, Richard; Scholz, Yvonne; Schaap, Martijn

    2015-03-01

    Effective air pollution and short-lived climate forcer mitigation strategies can only be designed when the effect of emission reductions on pollutant concentrations and health and ecosystem impacts are quantified. Within integrated assessment modeling source-receptor relationships (SRRs) based on chemistry transport modeling are used to this end. Currently, these SRRs are made using invariant emission time profiles. The LOTOS-EUROS model equipped with a source attribution module was used to test this assumption for renewable energy scenarios. Renewable energy availability and thereby fossil fuel back up are strongly dependent on meteorological conditions. We have used the spatially and temporally explicit energy model REMix to derive time profiles for backup power generation. These time profiles were used in LOTOS-EUROS to investigate the effect of emission timing on air pollutant concentrations and SRRs. It is found that the effectiveness of emission reduction in the power sector is significantly lower when accounting for the shift in the way emissions are divided over the year and the correlation of emissions with synoptic situations. The source receptor relationships also changed significantly. This effect was found for both primary and secondary pollutants. Our results indicate that emission timing deserves explicit attention when assessing the impacts of system changes on air quality and climate forcing from short lived substances.

  9. Questions Students Ask: About Terminal Velocity.

    ERIC Educational Resources Information Center

    Meyer, Earl R.; Nelson, Jim

    1984-01-01

    If a ball were given an initial velocity in excess of its terminal velocity, would the upward force of air resistance (a function of velocity) be greater than the downward force of gravity and thus push the ball back upwards? An answer to this question is provided. (JN)

  10. Simulation of air and ground temperatures in PMIP3/CMIP5 last millennium simulations: implications for climate reconstructions from borehole temperature profiles

    NASA Astrophysics Data System (ADS)

    García-García, A.; Cuesta-Valero, F. J.; Beltrami, H.; Smerdon, J. E.

    2016-04-01

    For climate models to simulate the continental energy storage of the Earth’s energy budget they must capture the processes that partition energy across the land-atmosphere boundary. We evaluate herein the thermal consequences of these processes as simulated by models in the third phase of the paleoclimate modelling intercomparison project and the fifth phase of the coupled model intercomparison project (PMIP3/CMIP5). We examine air and ground temperature tracking at decadal and centennial time-scales within PMIP3 last-millennium simulations concatenated to historical simulations from the CMIP5 archive. We find a strong coupling between air and ground temperatures during the summer from 850 to 2005 CE. During the winter, the insulating effect of snow and latent heat exchanges produce a decoupling between the two temperatures in the northern high latitudes. Additionally, we use the simulated ground surface temperatures as an upper boundary condition to drive a one-dimensional conductive model in order to derive synthetic temperature-depth profiles for each PMIP3/CMIP5 simulation. Inversion of these subsurface profiles yields temperature trends that retain the low-frequency variations in surface air temperatures over the last millennium for all the PMIP3/CMIP5 simulations regardless of the presence of seasonal decoupling in the simulations. These results demonstrate the robustness of surface temperature reconstructions from terrestrial borehole data and their interpretation as indicators of past surface air temperature trends and continental energy storage.

  11. Velocity Measurements of Free Surface Liquid Metal Flows in a Magnetic Field

    NASA Astrophysics Data System (ADS)

    Pfeffer, Scott; Ji, Hantao; Nornberg, Mark; Rhoads, John

    2008-11-01

    A potential probe diagnostic was developed and calibrated to map the velocity profile of free-surface liquid metal channel flow and quantify the effect an applied magnetic field played in shaping the velocity profile. The setup for this experiment consists of a wide aspect ratio channel sealed from the air, with argon replacing the air in the channel, placed within an electromagnet capable of producing more than a 2000 Gauss field perpendicular to the flow. An alloy of GaInSn, which is liquid at room temperature, is pumped through the channel by a screw pump at a specified rate. The velocity profile is obtained by measuring the voltage across pairs of probes. Various materials were used to determine which probe material would maximize the signal from the voltage induced by the Hall effect and reduce the voltage due to thermoelectric effects. Extensive calibration was then carried out to ensure an accurate velocity measurement. After amplification and filtering this signal gives us a good measurement of the velocity of the liquid metal over the cross-section of a specific probe.

  12. Simulation of colloidal fouling by coupling a dynamically updating velocity profile and electric field interactions with Force Bias Monte Carlo methods for membrane filtration.

    PubMed

    Boyle, Paul M; Houchens, Brent C; Kim, Albert S

    2013-06-01

    Pressure-driven flow through a channel with membrane walls is modeled for high particulate volume fractions of 10%. Particle transport is influenced by Brownian diffusion, shear-induced diffusion, and convection due to the axial crossflow. The particles are also subject to electrostatic double layer repulsion and van der Waals attraction, from both particle-particle and particle-membrane interactions. Force Bias Monte Carlo (FBMC) simulations predict the deposition of the particles onto the membranes, where both hydrodynamics and the change in particle potentials determine the probability that a proposed move is accepted. The particle volume fraction is used to determine an apparent local viscosity observed by the continuum flow. As particles migrate, the crossflow velocity field evolves in quasi-steady fashion with each time instance appearing fully developed in the downstream direction. Particles subject to combined hydrodynamic and electric effects (electrostatic double layer repulsion and van der Waals attraction) reach a more stable steady-state as compared to systems with only hydrodynamic effects considered. As expected, at higher crossflow Reynolds numbers more particles remain in the crossflow free stream.

  13. Characterization of self-propagating formation reactions in Ni/Zr multilayered foils using reaction heats, velocities, and temperature-time profiles

    DOE PAGES

    Barron, S. C.; Knepper, R.; Walker, N.; ...

    2011-01-11

    We report on intermetallic formation reactions in vapor-deposited multilayered foils of Ni/Zr with 70 nm bilayers and overall atomic ratios of Ni:Zr, 2 Ni:Zr, and 7 Ni:2 Zr. The sequence of alloy phase formation and the stored energy is evaluated at slow heating rates (~1 K/s) using differential scanning calorimetry (DSC) traces to 725ºC. All three chemistries initially form a Ni-Zr amorphous phase which crystallizes first to the intermetallic NiZr. The heat of reaction to the final phase is 34-36 kJ/mol atom for all chemistries. Intermetallic formation reactions are also studied at rapid heating rates (greater than 105 K/s) inmore » high temperature, self-propagating reactions which can be ignited in these foils by an electric spark. We find that reaction velocities and maximum reaction temperatures (Tmax) are largely independent of foil chemistry at 0.6 ± 0.1 m/s and 1220 ± 50 K, respectively, and that the measured Tmax is more than 200 K lower than predicted adiabatic temperatures (Tad). The difference between Tmax and Tad is explained by the prediction that transformation to the final intermetallic phases occurs after Tmax and results in the release of 20-30 % of the total heat of reaction and a delay in rapid cooling.« less

  14. Analysis of altimeter data jointly with seafloor electric data (vertically integrated velocity) and VCTD-yoyo data (detailed profiles of VCTD)

    NASA Technical Reports Server (NTRS)

    Tarits, Pascal D.; Menvielle, M.; Provost, C.; Filloux, J. H.

    1991-01-01

    We propose simultaneous analyses of the TOPEX/POSEIDON altimetry data, in situ data--mainly permanent seafloor electric recordings--and velocity, conductivity, temperature, density (VCTD)-yoyo data at several stations in areas of scientific interest. We are planning experiments in various areas of low and high energy levels. Several complementary and redundant methods will be used to characterize the ocean circulation and its short- and long-term variability. We shall emphasize long-term measurement using permanent stations. Our major initial objectives with the TOPEX/POSEIDON mission are the Confluence area in the Argentine Basin and the Circumpolar Antarctic Current. An early experiment was carried out in the Confluence zone in 1988 and 1990 (Confluence Principal Investigators, 1990) to prepare for an intensive phase later one. This intensive phase will include new types of instrumentation. Preliminary experiments will be carried out in the Mediterranean Sea (in 1991) and in the North Atlantic Ocean (in 1992, north of the Canary Islands) to test the new instrumentation.

  15. High-resolution H-band Spectroscopy of Be Stars with SDSS-III/APOGEE. II. Line Profile and Radial Velocity Variability

    NASA Astrophysics Data System (ADS)

    Chojnowski, S. Drew; Wisniewski, John P.; Whelan, David G.; Labadie-Bartz, Jonathan; Borges Fernandes, Marcelo; Lin, Chien-Cheng; Majewski, Steven R.; Stringfellow, Guy S.; Mennickent, Ronald E.; Roman-Lopes, Alexandre; Tang, Baitian; Hearty, Fred. R.; Holtzman, Jon A.; Pepper, Joshua; Zasowski, Gail

    2017-04-01

    We report on the H-band spectral variability of classical Be stars observed over the course of the Apache Point Galactic Evolution Experiment (APOGEE), one of four subsurveys comprising SDSS-III. As described in the first paper of this series, the APOGEE B-type emission-line (ABE) star sample was culled from the large number of blue stars observed as telluric standards during APOGEE observations. In this paper, we explore the multi-epoch ABE sample, consisting of 1100 spectra for 213 stars. These “snapshots” of the circumstellar disk activity have revealed a wealth of temporal variability including, but not limited to, gradual disappearance of the line emission and vice versa over both short and long timescales. Other forms of variability include variation in emission strength, emission peak intensity ratios, and emission peak separations. We also analyze radial velocities (RVs) of the emission lines for a subsample of 162 stars with sufficiently strong features, and we discuss on a case-by-case basis whether the RV variability exhibited by some stars is caused by binary motion versus dynamical processes in the circumstellar disks. Ten systems are identified as convincing candidates for binary Be stars with as of yet undetected companions.

  16. Characterization of self-propagating formation reactions in Ni/Zr multilayered foils using reaction heats, velocities, and temperature-time profiles

    SciTech Connect

    Barron, S. C.; Knepper, R.; Walker, N.; Weihs, T. P.

    2011-01-11

    We report on intermetallic formation reactions in vapor-deposited multilayered foils of Ni/Zr with 70 nm bilayers and overall atomic ratios of Ni:Zr, 2 Ni:Zr, and 7 Ni:2 Zr. The sequence of alloy phase formation and the stored energy is evaluated at slow heating rates (~1 K/s) using differential scanning calorimetry (DSC) traces to 725ºC. All three chemistries initially form a Ni-Zr amorphous phase which crystallizes first to the intermetallic NiZr. The heat of reaction to the final phase is 34-36 kJ/mol atom for all chemistries. Intermetallic formation reactions are also studied at rapid heating rates (greater than 105 K/s) in high temperature, self-propagating reactions which can be ignited in these foils by an electric spark. We find that reaction velocities and maximum reaction temperatures (Tmax) are largely independent of foil chemistry at 0.6 ± 0.1 m/s and 1220 ± 50 K, respectively, and that the measured Tmax is more than 200 K lower than predicted adiabatic temperatures (Tad). The difference between Tmax and Tad is explained by the prediction that transformation to the final intermetallic phases occurs after Tmax and results in the release of 20-30 % of the total heat of reaction and a delay in rapid cooling.

  17. Development of Hydroxyl Tagging Velocimetry for Low Velocity Flows

    NASA Technical Reports Server (NTRS)

    Andre, Matthieu A.; Bardet, Philippe M.; Burns, Ross A.; Danehy, Paul M.

    2016-01-01

    Hydroxyl tagging velocimetry (HTV) is a molecular tagging technique that relies on the photo-dissociation of water vapor into OH radicals and their subsequent tracking using laser induced fluorescence. Velocities are then obtained from time-of-flight calculations. At ambient temperature in air, the OH species lifetime is relatively short (<50 µs), making it suited for high speed flows. Lifetime and radicals formation increases with temperature, which allows HTV to also probe low-velocity, high-temperature flows or reacting flows such as flames. The present work aims at extending the domain of applicability of HTV, particularly towards low-speed (<10 m/s) and moderate (<500 K) temperature flows. Results are compared to particle image velocimetry (PIV) measurements recorded in identical conditions. Single shot and averaged velocity profiles are obtained in an air jet at room temperature. By modestly raising the temperature (100-200 degC) the OH production increases, resulting in an improvement of the signal-to-noise ratio (SNR). Use of nitrogen - a non-reactive gas with minimal collisional quenching - extends the OH species lifetime (to over 500 µs), which allows probing of slower flows or, alternately, increases the measurement precision at the expense of spatial resolution. Instantaneous velocity profiles are resolved in a 100degC nitrogen jet (maximum jet-center velocity of 6.5 m/s) with an uncertainty down to 0.10 m/s (1.5%) at 68% confidence level. MTV measurements are compared with particle image velocimetry and show agreement within 2%.

  18. Deep Downhole Seismic Testing at the Waste Treatment Plant Site, Hanford, WA. Volume VI S-Wave Measurements in Borehole C4997 Seismic Records, Wave-Arrival Identifications and Interpreted S-Wave Velocity Profile.

    SciTech Connect

    Stokoe, Kenneth H.; Li, Song Cheng; Cox, Brady R.; Menq, Farn-Yuh

    2007-06-06

    Velocity measurements in shallow sediments from ground surface to approximately 370 to 400 feet bgs were collected by Redpath Geophysics using impulsive S- and P-wave seismic sources (Redpath 2007). Measurements below this depth within basalt and sedimentary interbeds were made by UTA between October and December 2006 using the T-Rex vibratory seismic source in each of the three boreholes. Results of these measurements including seismic records, wave-arrival identifications and interpreted velocity profiles are presented in the following six volumes: I. P-Wave Measurements in Borehole C4993 II. P-Wave Measurements in Borehole C4996 III. P-Wave Measurements in Borehole C4997 IV. S-Wave Measurements in Borehole C4993 V. S-Wave Measurements in Borehole C4996 VI. S-Wave Measurements in Borehole C4997 In this volume (VI), all S-wave measurements are presented that were performed in Borehole C4997 at the WTP with T-Rex as the seismic source and the Lawrence Berkeley National Laboratory (LBNL) 3-D wireline geophone as the at-depth borehole receiver.

  19. Deep Downhole Seismic Testing at the Waste Treatment Plant Site, Hanford, WA. Volume V S-Wave Measurements in Borehole C4996 Seismic Records, Wave-Arrival Identifications and Interpreted S-Wave Velocity Profile.

    SciTech Connect

    Stokoe, Kenneth H.; Li, Song Cheng; Cox, Brady R.; Menq, Farn-Yuh

    2007-06-06

    Velocity measurements in shallow sediments from ground surface to approximately 370 to 400 feet bgs were collected by Redpath Geophysics using impulsive S- and P-wave seismic sources (Redpath 2007). Measurements below this depth within basalt and sedimentary interbeds were made by UTA between October and December 2006 using the T-Rex vibratory seismic source in each of the three boreholes. Results of these measurements including seismic records, wave-arrival identifications and interpreted velocity profiles are presented in the following six volumes: I. P-Wave Measurements in Borehole C4993 II. P-Wave Measurements in Borehole C4996 III. P-Wave Measurements in Borehole C4997 IV. S-Wave Measurements in Borehole C4993 V. S-Wave Measurements in Borehole C4996 VI. S-Wave Measurements in Borehole C4997 In this volume (V), all S-wave measurements are presented that were performed in Borehole C4996 at the WTP with T-Rex as the seismic source and the Lawrence Berkeley National Laboratory (LBNL) 3-D wireline geophone as the at-depth borehole receiver.

  20. Simulation of Air and Ground Temperatures in PMIP3/CMIP5 Last Millennium Simulations: Implications for Climate Reconstructions from Borehole Temperature Profiles

    NASA Astrophysics Data System (ADS)

    Beltrami, Hugo; García-García, Almudena; José Cuesta-Valero, Francisco; Smerdon, Jason

    2016-04-01

    For General Circulation Models (GCMs) to simulate the continental energy storage of the Earth's energy budget it is crucial that they correctly capture the processes that partition energy across the land-atmosphere boundary. We evaluate herein the characteristics of these processes as simulated by models in the third phase of the Paleoclimate Modelling Intercomparison Project and the fifth phase of the Coupled Model Intercomparison Project (PMIP3/CMIP5). We examine the seasonal differences between air and ground temperatures within PMIP3 last-millennium simulations concatenated with historical simulations from the CMIP5 archive. We find a strong air-ground coupling during the summer from 850 to 2000 CE. During the winter, the insulating effect of snow and latent heat exchanges produce a decoupling between air and ground temperatures in the northern high latitudes. Additionally, we use the simulated temperature trends as an upper boundary condition to force a one-dimensional conductive model to derive synthetic temperature-depth profiles for each PMIP3/CMIP5 simulation. The inversions of these subsurface profiles yield temperature trends that retain the surface temperature variations of the last millennium for all the PMIP3/CMIP5 simulations. These results support the use of underground temperatures to reconstruct past changes in ground surface temperature and to estimate the continental energy storage.

  1. New Technology-Large-Area Three- Dimensional Surface Profiling Using Only Focused Air-Coupled Ultrasound-Given 1999 R&D 100 Award

    NASA Technical Reports Server (NTRS)

    Roth, Don J.; Kautz, Harold E.; Abel, Phillip B.; Whalen, Mike F.; Hendricks, J. Lynne; Bodis, James R.

    2000-01-01

    Surface topography, which significantly affects the performance of many industrial components, is normally measured with diamond-tip profilometry over small areas or with optical scattering methods over larger areas. To develop air-coupled surface profilometry, the NASA Glenn Research Center at Lewis Field initiated a Space Act Agreement with Sonix, Inc., through two Glenn programs, the Advanced High Temperature Engine Materials Program (HITEMP) and COMMTECH. The work resulted in quantitative surface topography profiles obtained using only high-frequency, focused ultrasonic pulses in air. The method is nondestructive, noninvasive, and noncontact, and it does not require light-reflective surfaces. Air surface profiling may be desirable when diamond-tip or laserbased methods are impractical, such as over large areas, when a significant depth range is required, or for curved surfaces. When the configuration is optimized, the method is reasonably rapid and all the quantitative analysis facilities are online, including two- and three-dimensional visualization, extreme value filtering (for faulty data), and leveling.

  2. Velocity Field Measurements of Human Coughing Using Time Resolved Particle Image Velocimetry

    NASA Astrophysics Data System (ADS)

    Khan, T.; Marr, D. R.; Higuchi, H.; Glauser, M. N.

    2003-11-01

    Quantitative fluid mechanics analysis of human coughing has been carried out using new Time Resolved Particle Image Velocimetry (TRPIV). The study involves measurement of velocity vector time-histories and velocity profiles. It is focused on the average normal human coughing. Some work in the past on cough mechanics has involved measurement of flow rates, tidal volumes and sub-glottis pressure. However, data of unsteady velocity vector field of the exiting highly time-dependent jets is not available. In this study, human cough waveform data are first acquired in vivo using conventional respiratory instrumentation for various volunteers of different gender/age groups. The representative waveform is then reproduced with a coughing/breathing simulator (with or without a manikin) for TRPIV measurements and analysis. The results of this study would be useful not only for designing of indoor air quality and heating, ventilation and air conditioning systems, but also for devising means of protection against infectious diseases.

  3. Decreased group velocity in compositionally graded films.

    PubMed

    Gao, Lei

    2006-03-01

    A theoretical formalism is presented that describes the group velocity of electromagnetic signals in compositionally graded films. The theory is first based on effective medium approximation or the Maxwell-Garnett approximation to obtain the equivalent dielectric function in a z slice. Then the effective dielectric tensor of the graded film is directly determined, and the group velocities for ordinary and extraordinary waves in the film are derived. It is found that the group velocity is sensitively dependent on the graded profile. For a power-law graded profile f(x)=ax(m), increasing m results in the decreased extraordinary group velocity. Such a decreased tendency becomes significant when the incident angle increases. Therefore the group velocity in compositionally graded films can be effectively decreased by our suitable adjustment of the total volume fraction, the graded profile, and the incident angle. As a result, the compositionally graded films may serve as candidate material for realizing small group velocity.

  4. Coupling Between Air and Ground Temperatures in PMIP3/CMIP5 Last Millennium Simulations and the Implications for Climate Reconstructions from Borehole Temperature Profiles

    NASA Astrophysics Data System (ADS)

    Beltrami, H.; García-García, A.; Cuesta-Valero, F. J.; Smerdon, J. E.

    2015-12-01

    The continental energy storage for the second half of the 20th20^{th} century has been estimated from geothermal data to be about 7±1×1021J7 ± 1 × 10^{21} J under the assumption that there exists a long-term coupling between the lower atmosphere and the continental subsurface. For General Circulation Models (GCMs) to simulate the continental energy storage of the Earth's energy budget, however, it is crucial that they correctly capture the processes that partition energy across the land-atmosphere boundary. We evaluate herein the characteristics of these processes as simulated by models in the third phase of the Paleoclimate Modelling Intercomparison Project and the fifth phase of the Coupled Model Intercomparison Project (PMIP33/CMIP55). We examine the seasonal differences between air and ground temperatures within PMIP3 last-millennium simulations concatenated with historical simulations from the CMIP5 archive. We find a strong air-ground coupling during the summer from 850850 to 20002000 CE. During the winter, the insulating effect of snow and latent heat exchanges produce a decoupling between air and ground temperatures in the northern high latitudes. These seasonal differences decrease with depth, supporting the central assumption of climate reconstructions from borehole temperature profiles. Additionally, we use the simulated temperature trends as an upper boundary condition to force a one-dimensional conductive model to derive synthetic temperature-depth profiles for each PMIP3/CMIP5 simulation. The inversions of these subsurface profiles yield temperature trends that retain the surface temperature variations of the last millennium for all the PMIP3/CMIP5 simulations. These results support the use of underground temperatures to reconstruct past changes in ground surface temperature and to estimate the continental energy storage. Results also provide guidance for improving the land-surface components of GCMs.

  5. Depth of maximum of air-shower profiles at the Pierre Auger Observatory. I. Measurements at energies above 1 017.8 eV

    NASA Astrophysics Data System (ADS)

    Aab, A.; Abreu, P.; Aglietta, M.; Ahn, E. J.; Al Samarai, I.; Albuquerque, I. F. M.; Allekotte, I.; Allen, J.; Allison, P.; Almela, A.; Alvarez Castillo, J.; Alvarez-Muñiz, J.; Alves Batista, R.; Ambrosio, M.; Aminaei, A.; Anchordoqui, L.; Andringa, S.; Aramo, C.; Aranda, V. M.; Arqueros, F.; Asorey, H.; Assis, P.; Aublin, J.; Ave, M.; Avenier, M.; Avila, G.; Awal, N.; Badescu, A. M.; Barber, K. B.; Bäuml, J.; Baus, C.; Beatty, J. J.; Becker, K. H.; Bellido, J. A.; Berat, C.; Bertaina, M. E.; Bertou, X.; Biermann, P. L.; Billoir, P.; Blaess, S.; Blanco, M.; Bleve, C.; Blümer, H.; Boháčová, M.; Boncioli, D.; Bonifazi, C.; Bonino, R.; Borodai, N.; Brack, J.; Brancus, I.; Bridgeman, A.; Brogueira, P.; Brown, W. C.; Buchholz, P.; Bueno, A.; Buitink, S.; Buscemi, M.; Caballero-Mora, K. S.; Caccianiga, B.; Caccianiga, L.; Candusso, M.; Caramete, L.; Caruso, R.; Castellina, A.; Cataldi, G.; Cazon, L.; Cester, R.; Chavez, A. G.; Chiavassa, A.; Chinellato, J. A.; Chudoba, J.; Cilmo, M.; Clay, R. W.; Cocciolo, G.; Colalillo, R.; Coleman, A.; Collica, L.; Coluccia, M. R.; Conceição, R.; Contreras, F.; Cooper, M. J.; Cordier, A.; Coutu, S.; Covault, C. E.; Cronin, J.; Curutiu, A.; Dallier, R.; Daniel, B.; Dasso, S.; Daumiller, K.; Dawson, B. R.; de Almeida, R. M.; De Domenico, M.; de Jong, S. J.; de Mello Neto, J. R. T.; De Mitri, I.; de Oliveira, J.; de Souza, V.; del Peral, L.; Deligny, O.; Dembinski, H.; Dhital, N.; Di Giulio, C.; Di Matteo, A.; Diaz, J. C.; Díaz Castro, M. L.; Diogo, F.; Dobrigkeit, C.; Docters, W.; D'Olivo, J. C.; Dorofeev, A.; Dorosti Hasankiadeh, Q.; Dova, M. T.; Ebr, J.; Engel, R.; Erdmann, M.; Erfani, M.; Escobar, C. O.; Espadanal, J.; Etchegoyen, A.; Facal San Luis, P.; Falcke, H.; Fang, K.; Farrar, G.; Fauth, A. C.; Fazzini, N.; Ferguson, A. P.; Fernandes, M.; Fick, B.; Figueira, J. M.; Filevich, A.; Filipčič, A.; Fox, B. D.; Fratu, O.; Fröhlich, U.; Fuchs, B.; Fujii, T.; Gaior, R.; García, B.; Garcia Roca, S. T.; Garcia-Gamez, D.; Garcia-Pinto, D.; Garilli, G.; Gascon Bravo, A.; Gate, F.; Gemmeke, H.; Ghia, P. L.; Giaccari, U.; Giammarchi, M.; Giller, M.; Glaser, C.; Glass, H.; Gómez Berisso, M.; Gómez Vitale, P. F.; Gonçalves, P.; Gonzalez, J. G.; González, N.; Gookin, B.; Gordon, J.; Gorgi, A.; Gorham, P.; Gouffon, P.; Grebe, S.; Griffith, N.; Grillo, A. F.; Grubb, T. D.; Guarino, F.; Guedes, G. P.; Hampel, M. R.; Hansen, P.; Harari, D.; Harrison, T. A.; Hartmann, S.; Harton, J. L.; Haungs, A.; Hebbeker, T.; Heck, D.; Heimann, P.; Herve, A. E.; Hill, G. C.; Hojvat, C.; Hollon, N.; Holt, E.; Homola, P.; Hörandel, J. R.; Horvath, P.; Hrabovský, M.; Huber, D.; Huege, T.; Insolia, A.; Isar, P. G.; Jandt, I.; Jansen, S.; Jarne, C.; Josebachuili, M.; Kääpä, A.; Kambeitz, O.; Kampert, K. H.; Kasper, P.; Katkov, I.; Kégl, B.; Keilhauer, B.; Keivani, A.; Kemp, E.; Kieckhafer, R. M.; Klages, H. O.; Kleifges, M.; Kleinfeller, J.; Krause, R.; Krohm, N.; Krömer, O.; Kruppke-Hansen, D.; Kuempel, D.; Kunka, N.; LaHurd, D.; Latronico, L.; Lauer, R.; Lauscher, M.; Lautridou, P.; Le Coz, S.; Leão, M. S. A. B.; Lebrun, D.; Lebrun, P.; Leigui de Oliveira, M. A.; Letessier-Selvon, A.; Lhenry-Yvon, I.; Link, K.; López, R.; Lopez Agüera, A.; Louedec, K.; Lozano Bahilo, J.; Lu, L.; Lucero, A.; Ludwig, M.; Malacari, M.; Maldera, S.; Mallamaci, M.; Maller, J.; Mandat, D.; Mantsch, P.; Mariazzi, A. G.; Marin, V.; Mariş, I. C.; Marsella, G.; Martello, D.; Martin, L.; Martinez, H.; Martínez Bravo, O.; Martraire, D.; Masías Meza, J. J.; Mathes, H. J.; Mathys, S.; Matthews, J.; Matthews, J. A. J.; Matthiae, G.; Maurel, D.; Maurizio, D.; Mayotte, E.; Mazur, P. O.; Medina, C.; Medina-Tanco, G.; Meissner, R.; Melissas, M.; Melo, D.; Menshikov, A.; Messina, S.; Meyhandan, R.; Mićanović, S.; Micheletti, M. I.; Middendorf, L.; Minaya, I. A.; Miramonti, L.; Mitrica, B.; Molina-Bueno, L.; Mollerach, S.; Monasor, M.; Monnier Ragaigne, D.; Montanet, F.; Morello, C.; Mostafá, M.; Moura, C. A.; Muller, M. A.; Müller, G.; Müller, S.; Münchmeyer, M.; Mussa, R.; Navarra, G.; Navas, S.; Necesal, P.; Nellen, L.; Nelles, A.; Neuser, J.; Nguyen, P.; Niechciol, M.; Niemietz, L.; Niggemann, T.; Nitz, D.; Nosek, D.; Novotny, V.; Nožka, L.; Ochilo, L.; Olinto, A.; Oliveira, M.; Pacheco, N.; Pakk Selmi-Dei, D.; Palatka, M.; Pallotta, J.; Palmieri, N.; Papenbreer, P.; Parente, G.; Parra, A.; Paul, T.; Pech, M.; PÈ©kala, J.; Pelayo, R.; Pepe, I. M.; Perrone, L.; Petermann, E.; Peters, C.; Petrera, S.; Petrov, Y.; Phuntsok, J.; Piegaia, R.; Pierog, T.; Pieroni, P.; Pimenta, M.; Pirronello, V.; Platino, M.; Plum, M.; Porcelli, A.; Porowski, C.; Prado, R. R.; Privitera, P.; Prouza, M.; Purrello, V.; Quel, E. J.; Querchfeld, S.; Quinn, S.; Rautenberg, J.; Ravel, O.; Ravignani, D.; Revenu, B.; Ridky, J.; Riggi, S.; Risse, M.; Ristori, P.; Rizi, V.; Rodrigues de Carvalho, W.; Rodriguez Cabo, I.; Rodriguez Fernandez, G.; Rodriguez Rojo, J.; Rodríguez-Frías, M. D.; Rogozin, D.; Ros, G.; Rosado, J.; Rossler, T.; Roth, M.; Roulet, E.; Rovero, A. C.; Saffi, S. J.; Saftoiu, A.; Salamida, F.; Salazar, H.; Saleh, A.; Salesa Greus, F.; Salina, G.; Sánchez, F.; Sanchez-Lucas, P.; Santo, C. E.; Santos, E.; Santos, E. M.; Sarazin, F.; Sarkar, B.; Sarmento, R.; Sato, R.; Scharf, N.; Scherini, V.; Schieler, H.; Schiffer, P.; Schmidt, D.; Scholten, O.; Schoorlemmer, H.; Schovánek, P.; Schulz, A.; Schulz, J.; Schumacher, J.; Sciutto, S. J.; Segreto, A.; Settimo, M.; Shadkam, A.; Shellard, R. C.; Sidelnik, I.; Sigl, G.; Sima, O.; Śmiałkowski, A.; Šmída, R.; Snow, G. R.; Sommers, P.; Sorokin, J.; Squartini, R.; Srivastava, Y. N.; Stanič, S.; Stapleton, J.; Stasielak, J.; Stephan, M.; Stutz, A.; Suarez, F.; Suomijärvi, T.; Supanitsky, A. D.; Sutherland, M. S.; Swain, J.; Szadkowski, Z.; Szuba, M.; Taborda, O. A.; Tapia, A.; Tartare, M.; Tepe, A.; Theodoro, V. M.; Timmermans, C.; Todero Peixoto, C. J.; Toma, G.; Tomankova, L.; Tomé, B.; Tonachini, A.; Torralba Elipe, G.; Torres Machado, D.; Travnicek, P.; Trovato, E.; Tueros, M.; Ulrich, R.; Unger, M.; Urban, M.; Valdés Galicia, J. F.; Valiño, I.; Valore, L.; van Aar, G.; van Bodegom, P.; van den Berg, A. M.; van Velzen, S.; van Vliet, A.; Varela, E.; Vargas Cárdenas, B.; Varner, G.; Vázquez, J. R.; Vázquez, R. A.; Veberič, D.; Verzi, V.; Vicha, J.; Videla, M.; Villaseñor, L.; Vlcek, B.; Vorobiov, S.; Wahlberg, H.; Wainberg, O.; Walz, D.; Watson, A. A.; Weber, M.; Weidenhaupt, K.; Weindl, A.; Werner, F.; Widom, A.; Wiencke, L.; Wilczyńska, B.; Wilczyński, H.; Will, M.; Williams, C.; Winchen, T.; Wittkowski, D.; Wundheiler, B.; Wykes, S.; Yamamoto, T.; Yapici, T.; Yuan, G.; Yushkov, A.; Zamorano, B.; Zas, E.; Zavrtanik, D.; Zavrtanik, M.; Zaw, I.; Zepeda, A.; Zhou, J.; Zhu, Y.; Zimbres Silva, M.; Ziolkowski, M.; Zuccarello, F.; Pierre Auger Collaboration

    2014-12-01

    We report a study of the distributions of the depth of maximum, Xmax, of extensive air-shower profiles with energies above 1 017.8 eV as observed with the fluorescence telescopes of the Pierre Auger Observatory. The analysis method for selecting a data sample with minimal sampling bias is described in detail as well as the experimental cross-checks and systematic uncertainties. Furthermore, we discuss the detector acceptance and the resolution of the Xmax measurement and provide parametrizations thereof as a function of energy. The energy dependence of the mean and standard deviation of the Xmax distributions are compared to air-shower simulations for different nuclear primaries and interpreted in terms of the mean and variance of the logarithmic mass distribution at the top of the atmosphere.